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Simulated organic acid weathering of granodiorite and basalt Aceman, Sheila 1989

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SIMULATED ORGANIC ACID WEATHERING OF GRANODIORITE AND BASALT by SHEILA ACEMAN .Sc.,  The U n i v e r s i t y  o f B r i t i s h Columbia, 198  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department o f S o i l Science)  We a c c e p t t h i s t h e s i s as conforming to the required  standard  THE UNIVERSITY OF BRITISH COLUMBIA J u l y , 1989 ® S h e i l a Aceman  In  presenting  degree freely  at  the  available  copying  of  department publication  this  of  in  partial  fulfilment  University  of  British  Columbia,  for  this or  thesis  reference  thesis by  this  for  his thesis  and  study.  scholarly  or  her  for  of  *So  ic  Sc/  The University of British Columbia Vancouver, Canada  DE-6 (2/88)  C-6T  gain  the  shall  requirements  agree  that  agree  may  representatives.  financial  g>\)  I  I further  purposes  permission.  Department  of  be  It not  that  the  be  an  advanced  Library shall  permission for  granted  is  for  by  understood allowed  the  make  extensive  head  that  without  it  of  copying my  my or  written  ABSTRACT  Basalt size)  and  granodiorite  were leached by  organic acids,  (medium t o  three  low  namely c i t r i c ,  concentration.  f i n e sand p a r t i c l e  m o l e c u l a r weight a l i p h a t i c  o x a l i c and  a c e t i c a c i d of  To evaluate the e f f e c t i v e n e s s  a c i d s i n d i s s o l v i n g the rock samples, two .005M HC1  and  distilled  o f the  control  water were added t o  . 1M  organic  solutions,  the  number  of  d i s s o l u t i o n treatments. D i s s o l u t i o n of ions treatment  from g r a n o d i o r i t e ,  shown i n p a r e n t h e s i s ,  decreased  by  the  leaching  i n the  following  order: Fe(OX) > A1(0X) ~ Si(OX) > Ca(CIT) ~ Mg(OX) - K(OX) Dissolution following Fe(CIT)  of  ions  from  basalt  > Na(OX)  decreased  in  the  order:  >  Si(CIT)  > Mg(CIT)  >  Ca(CIT)  >  Al(OX,  ACETIC)  >  Na(OX) > K(HC1) Oxalic  a c i d e f f e c t i v e l y outcompeted c i t r i c  weathering of g r a n o d i o r i t e constants  for  differences  certain in  concentration competition oxidation There  pH  of  IT  the  ions  in solution  the  i n s p i t e of h a v i n g lower s t a b i l i t y  elements. of  acid in  for  This  was  solutions and  (affecting  anionic  ligand  attributed  species),  s i t e s and  to  both ionic  geometry  and  s t a t e of ions i n the parent m i n e r a l . was  no  conclusive  c h e l a t i o n of K* or Na+  took p l a c e  evidence i n any  to  indicate  of the  that  experiments.  iii However, mass balance c a l c u l a t i o n s r e v e a l e d t h a t o x a l i c a c i d extracted citric  approximately  acid extracted  40-50% o f the K from  approximately 12%.  granodiorite;  These l e v e l s were  s i g n i f i c a n t l y h i g h e r than those e x t r a c t e d by n o n - s e q u e s t e r i n g agents.  XRD  analysis  of g r a n o d i o r i t i c - o x a l a t e p r e c i p i t a t e  suggested t h e p o s s i b l e formation The  chelating  acids,  o f a K-oxalate s a l t .  citric  and  oxalic,  greatly  outcompeted a c e t i c a c i d and HC1 o f s i m i l a r pH f o r m u l t i - v a l e n t cations Fe,  i n both b a s a l t and g r a n o d i o r i t e .  A l , and  calculated  S i , i n s o l u t i o n were  concentrations  Concentrations  many  fold  higher  of than  of those ions i n e q u i l i b r i u m w i t h  the amorphous oxide i n water. Oxalic  acid  and c i t r i c  d i s s o l u t i o n curves,  from 11 weeks o f l e a c h i n g , showed i n i t i a l l y followed  by d e c l i n i n g r a t e s  which  determined  increasing rates  approached  towards t h e e l e v e n t h week of t h e experiment.  steady  state  Declining rates  f o l l o w e d by s t e a d y - s t a t e r a t e s were a t t r i b u t e d t o t h e presence of  hyperfines  increase surface  the build-up  of ions  o f secondary  i n solutions,  p r e c i p i t a t e s , the  and t o an e r o d i n g  layer.  Non-chelating  acids  namely  acetic  acid,  HC1  r e v e a l e d d i s s o l u t i o n curves t h a t were approximately (steady-state)  granodiorite  and  H0 2  constant  throughout the 11 week weathering p e r i o d .  XRD, XRF, SEM, and EDX analyses  analyses  leached  as  provided  well  as  AA  evidence  o f weathered b a s a l t and  spectrophotometric which  indicated  solution  incongruent  iv dissolution  of granodiorite  and b a s a l t  by  all5  leaching  treatments. SEM and XRF a n a l y s e s i n d i c a t e d t h a t c i t r i c a c i d was l e s s effective  than  granodiorite.  oxalic EDX  acid  i n forming  revealed  that  precipitates  t h e amorphous p r e c i p i t a t e  which d i d form i n c i t r i c a c i d c o n s i s t e d p r i m a r i l y o f Fe. analyses of inorganic coatings Fe i n 1:1  from  EDX  i n d i c a t e d predominantly S i and  ratio.  Although c i t r i c a c i d was a b l e t o e x t r a c t g r e a t e r of Fe from b a s a l t than g r a n o d i o r i t e ,  extractable  amounts  Fe, A l and  S i a n a l y s i s and SEM d e t e c t e d no organo-amorphous p r e c i p i t a t e s . Also  EDX of i n o r g a n i c  or A l .  surfaces  showed no accumulation o f Fe  I t was concluded t h a t t h e Fe e x t r a c t e d  from t h e b a s a l t  remained i n complexed o r s o l u b l e form due t o t h e h i g h e r pH (35) of t h e b a s a l t i c s o l u t i o n . An  amorphous p r e c i p i t a t e  granodiorite  with  formed  oxalic acid.  EDX  from  the l e a c h i n g  analysis  of  gave evidence  t h a t t h e p r e c i p i t a t e c o n s i s t e d p r i m a r i l y o f S i and Fe i n a 1:1 ratio.  An amorphous p r e c i p i t a t e formed a l s o from t h e l e a c h i n g  of b a s a l t with o x a l i c a c i d . the  p r e c i p i t a t e consisted  ratio.  Data  from  c a l c u l a t i o n s as w e l l  molar  EDX a n a l y s i s gave evidence t h a t primarily oxide  as XRD,  o f Mg  ratios  and Fe i n a and  XRF, e x t r a c t a b l e  mass  inorganic  balance  Fe, A l and S i  a n a l y s e s were r e l i e d upon t o determine t h e p o s s i b l e and  1:1  components o f these p r e c i p i t a t e s .  organic  V  TABLE OF CONTENTS Page i  ABSTRACT  i i  TABLE OF CONTENTS  i i  LIST OF TABLES  v i i  LIST OF FIGURES  viii  ACKNOWLEDGEMENTS  xi  INTRODUCTION  1  MATERIALS AND METHODS  6  LITERATURE REVIEW RESULTS AND A. S e c t i o n B. S e c t i o n C. S e c t i o n  '  DISCUSSION 1 II III  16 43 43 68 91  SUMMARY AND CONCLUSIONS  115  BIBLIOGRAPHY  125  APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX APPENDIX  A A B C D E F G H 1 J K K L M N  x  2  x 2  '  137 144 148 156 164 17 2 176 179 183 187 194 198 2 03 208 211 214  vi LIST OF TABLES Page T a b l e 1: T a b l e 2: T a b l e 3: T a b l e 4: T a b l e 5:  T a b l e 6:  Chemical D e s c r i p t i o n of C i t r i c , O x a l i c and A c e t i c A c i d  7  S t a b i l i t y Constants of Oxalate and C i t r a t e Metal Ligands  45  Source o f Ions From B a s a l t i c and G r a n o d i o r i t i c Parents M a t e r i a l  65  Composition o f M i n e r a l s I d e n t i f i e d i n G r a n o d i o r i t e & B a s a l t by XRD A n a l y s e s  66  Changes i n XRD Peak I n t e n s i t i e s i n Basaltic & Granodioritic Minerals F o l l o w i n g 11 Week Batch D i s s o l u t i o n Experiment  67  Chemical D e s c r i p t i o n of C i t r a t e and Oxalate S a l t s  92  vii LIST OF FIGURES Page F i g u r e 1: F i g u r e 2: F i g u r e 3:  P o s s i b l e pathways o f i r o n oxide •under near pedogenic c o n d i t i o n s The a c t i v i t y o f F e maintained F e ( I I I ) oxides and s o i l - F e 3 +  formation 30 by 30  P r e d i c t e d mole f r a c t i o n diagrams f o r c i t r a t e and o x a l a t e i n a n u t r i e n t s o l u t i o n i n e q u i l i b r i u m with Fe(OH) (amorph)  46  The a c t i v i t y o f A l and i t s h y d r o l y s i s species i n e q u i l i b r i u m with g i b b s i t e . . . .  53  3  F i g u r e 4: F i g u r e 5:  3 +  The s o l u b i l i t y o f v a r i o u s aluminum  oxides 53  F i g u r e 6:  Hyperfines  adhering  to g r a n i t i c surface.  71  F i g u r e 7:  Hyperfines  adhering  to b a s a l t i c surface.  71  F i g u r e 8:  Basaltic g r a i n leached by o x a l i c a c i d f o r 11 weeks. Note absence o f h y p e r f i n e s and prominent e t c h - p i t t i n g  F i g u r e 9:  Granodiorite crust materials  72  leached  by c i t r i c a c i d f o r 11 weeks  76  F i g u r e 10:  EDX o f sample shown i n F i g u r e 11  76  F i g u r e 11:  G r a n o d i o r i t e g r a i n weathered by o x a l i c a c i d f o r 11 weeks Mica g r a i n leached by o x a l i c a c i d - 11 weeks  F i g u r e 12: F i g u r e 13: F i g u r e 14:  Mica g r a i n leached by o x a l i c a c i d - 11 weeks.  77 81 81  Mica g r a i n leached by o x a l i c a c i d 11 weeks  82  F i g u r e 15:  EDX o f sample shown i n F i g u r e 14  82  F i g u r e 16:  G r a n o d i o r i t i c g r a i n leached by o x a l i c a c i d 11 weeks EDX o f sample shown i n F i g u r e 16  84 84  F i g u r e 17:  viii Page F i g u r e 18: F i g u r e 19: F i g u r e 20: F i g u r e 21: F i g u r e 22: F i g u r e 23: F i g u r e 24: F i g u r e 25:  Basaltic grain f o r 11 weeks  leached by o x a l i c  Basaltic grain f o r 11 weeks  leached by o x a l i c  acid 86 acid 86  Granodiorite grain a c i d f o r 11 weeks Granodioritic grain a c i d f o r 11 weeks  leached  i n oxalic 87  leached  Basaltic grain f o r 11 weeks  leached  Basaltic grain f o r 11 weeks  leached  Basaltic grain f o r 11 weeks  leached  i n oxalic 87  i n oxalic  acid 88  i n oxalic  acid 88  i n oxalic  G r a n o d i o r i t e g r a i n leached a c i d f o r 11 weeks  acid 89  i n oxalic 90  F i g u r e 26:  EDX of sample shown i n F i g u r e 27  94  F i g u r e 27:  M i n e r a l fragments i n g r a n o d i o r i t i c c r u s t found a f t e r 11 weeks o f leaching i n oxalic acid  94  F i g u r e 28:  EDX o f sample shown i n F i g u r e 29  95  F i g u r e 29:  Amorphous p r e c i p i t a t e i n g r a n o d i o r i t i c c r u s t found a f t e r 11 weeks o f l e a c h i n g in oxalic acid  95  F i g u r e 30:  EDX of sample shown i n F i g u r e 31  99  F i g u r e 31:  Amorphous p r e c i p i t a t e i n b a s a l t i c c r u s t formed a f t e r 11 weeks o f l e a c h i n g i n oxalic acid  99  F i g u r e 32:  EDX o f sample shown i n F i g u r e 33  102  F i g u r e 33:  Amorphous p r e c i p i t a t e i n g r a n o d i o r i t i c c r u s t formed a f t e r 11 weeks o f l e a c h i n g in c i t r i c acid  102  EDX o f sample shown i n F i g u r e 35  104  F i g u r e 34:  ix Page  F i g u r e 35:  G r a n o d i o r i t i c " c r u s t " leached i n citric  a c i d f o r 11 weeks  104  F i g u r e 36:  EDX o f sample shown i n F i g u r e 37  F i g u r e 37:  B a s a l t i c g r a i n s leached i n c i t r i c a c i d f o r 11 weeks B a s a l t i c g r a i n leached i n H 0 f o r 11 weeks  F i g u r e 38: F i g u r e 39:  106 106  2  G r a n o d i o r i t i c g r a i n s leached i n H 0 f o r 11 weeks o  110 110  X  ACKNOWLEDGEMENTS  During the  course of my  from many sources. Dr. L.M.  research  I have r e c e i v e d  Thanks and a p p r e c i a t i o n , f i r s t o f a l l t o  L a v k u l i c h f o r h i s support and words of encouragement.  Thanks a l s o t o Dr.  L.E.  Lowe and  found time t o answer any enquiry.  Dr.  Dr. Mary Barnes who  questions  and  stimulated  Hans S c h r e i e r a l s o served  o f f e r e d s e v e r a l suggestions  on my  technical  assistance  t h e s i s would not  be  in  committee  and  regarding t h i s p r o j e c t .  the  laboratory  without  gave  whom  completed: Yvonne Duma, M a r t i n  Mary Majors, Maureen Soon, Bernie Von  me  this  Hilmer,  S p i n d l e r , Lendle Wade,  i n p a r t i c u l a r E v e l i n e Wolterson. I  Dr. A. Dr.  always  scientific  Much a p p r e c i a t i o n i s a l s o extended t o those who  and  help  also  received  academic  help  from  Dr.  B.  Barnes,  Bomke, Dr. T. Brown, Dr. D. C l a v e t t e , Dr. J . de V r i e s ,  B. James, and  Dr. C.  Orvig.  1  I N T R O D U C T I O N Chemical weathering o f r o c k s and m i n e r a l s i s one of the most  important  processes  by  which  chemical  f r a c t i o n a t e d a t the s u r f a c e o f the e a r t h .  elements  Much o f the e a r l i e r  r e s e a r c h on the s u b j e c t o f m i n e r a l weathering was bulk  chemistry  or  mineralogy  f u n c t i o n o f geomorphic influential  of  are  vertical  based  profiles  or c l i m a t i c f a c t o r s .  as  on a  Among the most  concepts t o emerge from the e a r l y work were the  "weathering s e r i e s " of G o l d i c h (1938), the "weathering index" of Jackson and co-workers of elemental m o b i l i t y  (Jackson e t a l . 1948), and a v a r i e t y  indices.  G o l d i c h ' s weathering s e r i e s , perhaps the most w e l l known and  quoted  i n many books,  i s merely  the  observation that  c e r t a i n m i n e r a l s weather more r a p i d l y than o t h e r s .  However,  numerous attempts t o u n r a v e l the u n d e r l y i n g b a s i s o f G o l d i c h ' s weathering s e r i e s  i n terms  o f thermodynamics  o r bonding e n e r g i e s i n s i l i c a t e l a t t i c e s still  failed  to  produce  a  e x p l a n a t i o n f o r the s t a b i l i t y  single  (Curtis  1976),  ( K e l l e r 1954), have  unifying  theoretical  sequence.  Weathering sequences of secondary m i n e r a l s (e.g. Jackson e t a l . ) are a l s o based on o b s e r v a t i o n but f a i l the  underlying  sequence. sequence:  mineralogical  basis  The most extreme view  for  t o determine  the  h o l d s t h a t the  weathering weathering  2  Primary s i l i c a t e is  i n fact  leaching  a  reaction  with  ,silica.  > smectite  the  series,  subsequent  > kaolinite brought removal  > gibbsite  about of  by  prolonged  cations  The d u r a t i o n o f l e a c h i n g dominates  and  then  t h i s view,  with  g i b b s i t e seen as the most advanced product o f weathering. 1963  however,  direct  Grant  (1963,  transformation of  1964), primary  showed  that  feldspars  there  to  primary m i n e r a l s and i t s r e s i l i c a t i o n t o k a o l i n i t e . out  by  Schwertman and  Taylor  (1977),  is a  kaolinite.  Eswaran e t a l . (1977), d i s c o v e r e d formation o f g i b b s i t e  pointed  In  from  A l s o , as  reduction  or  c h e l a t i o n - s o l u t i o n and o x i d a t i o n - p r e c i p i t a t i o n r e a c t i o n s make it  difficult  stability  t o p o s i t i o n i r o n oxides i n m i n e r a l weathering-  sequences.  They p a r t i c i p a t e i n n e a r l y a l l stages  of weathering and i n d i c a t e an advanced stage o n l y i f s t r o n g l y accumulated under a e r o b i c c o n d i t i o n s . Clearly, outside  c o n f u s i o n has  of t h e i r  resulted  environmental  from  context.  viewing minerals Although  in  1957  K e l l e r r e c o g n i z e d t h a t m i n e r a l s t a b i l i t y depends on both the thermodynamic s u s c e p t i b i l i t y  of the parent m a t e r i a l and  chemistry of the reactant s o l u t i o n ,  i t i s o n l y i n the  the last  decade t h a t r e s e a r c h has focused on the importance o f aqueous s o l u t i o n c h e m i s t r y i n the d i s s o l u t i o n o f primary and secondary minerals. The  labile  transformation  of  aqueous dissolved  phase  undergoes  constituents  into  continuous different  c h e m i c a l s p e c i e s over a broad range o f r e a c t i o n time s c a l e s .  3  T h i s k i n e t i c a l l y complex p r o c e s s i s the e s s e n t i a l f o r c e t h a t drives s o i l chemical which  p r o f i l e development and  weathering  are  governs the p a t t e r n s of  ( S p o s i t o , 1981).  n o n - s t o i c h i o m e t r i c phases  For  example,  reacting  with  s o l u t i o n s cannot be d e s c r i b e d by one c h a r a c t e r i s t i c for  their  composition  composition  of  the  precipitation.  may  aqueous  change  as  phase,  during  Thermodynamic  a  clays, aqueous  formula,  function or  calculations  of  after  of  the their  equilibria  between multi-component s o l i d s o l u t i o n s and aqueous s o l u t i o n s are d i f f i c u l t  t o i s o l a t e and understand  i s not y e t a v a i l a b l e . been developed water-rock  Computer models have, however, r e c e n t l y  (e.g. F r i t z ,  1985)  which a l l o w i n t r o d u c t i o n i n  i n t e r a c t i o n m o d e l l i n g o f m i n e r a l phases which v a r y  w i t h the composition of the Much remains t o be  solution.  l e a r n e d r e g a r d i n g the v e r y  changes i n s o l u t i o n chemistry brought minerals  i n the  chemical  and  it difficult one  and a g e n e r a l theory  about by weathering  n a t u r a l environment.  biological  complex  In  soils,  factors continually  of  physical,  i n t e r a c t making  t o i s o l a t e and q u a n t i f y the c o n t r i b u t i o n of any  f a c t o r a t any g i v e n time. It  was  environment  decided by  therefore  artificially  to  simplify  and  g r a n o d i o r i t e w i t h f i v e d i f f e r e n t e x t r a c t a n t s comprising  both  to  crushed  weathering basalt  o r g a n i c and i n o r g a n i c a c i d s .  leaching  a  The focus of the experiment  was  study the changes over time i n s o l u t i o n c h e m i s t r y f o r each  l e a c h i n g treatment.  P r e c i p i t a t i o n p r o d u c t s , which formed as  4  ionic  species  were a l s o  i n s o l u t i o n sought lower f r e e energy l e v e l s ,  analyzed.  Physical  and  chemical  changes  in  the  weathered b a s a l t and g r a n o d i o r i t e were only noted i n o r d e r t o e x p l a i n c e r t a i n f e a t u r e s of s o l u t i o n - p r e c i p i t a t i o n e q u i l i b r i a . Accordingly, I, I I and  t h r e e main t o p i c s f o r d i s c u s s i o n  I I I i n Results  and Discussion)  (sections  were chosen i n order  t o u n i f y the broad scan o f i n f o r m a t i o n which r e s u l t e d from the analyses. of  the  The f i r s t t o p i c considered the chemical composition  leaching  solutions  a c i d treatment.  The  as  influenced  by  parent rock  second h i g h l i g h t e d the k i n e t i c  and  features  of d i s s o l u t i o n , i . e . the r e l a t i v e r a t e s of change o f s o l u t i o n c h e m i s t r y over time, and the  formation  of  the t h i r d  organo  and  included  amorphous  a discussion  precipitates  on  from  s o l u t i o n products. More s p e c i f i c a l l y the o b j e c t i v e s of t h i s study were: 1.  To e v a l u a t e the e f f e c t i v e n e s s of two non  chelating  acids  in  c h e l a t i n g and  dissolving  three  basalt  and  dissolution  is  granodiorite. 2.  To  determine  whether  the  extent  of  c o r r e l a t e d w i t h s t a b i l i t y constants of o r g a n i c a c i d s ,  pH  o f s o l u t i o n , or type of m i n e r a l i n the p a r e n t rock. 3.  To (11  t r a c e the weeks)  changes i n r a t e s of d i s s o l u t i o n over time and  propose  possible  explanations  for  the  k i n e t i c behaviour. 4.  To  ascertain  congruent.  whether  dissolution  was  incongruent  or  5  5.  To a n a l y z e p r e c i p i t a t i o n p r o d u c t s formed from s o l u t i o n . Finally,  light in  i t was  hoped t h a t  on f u r t h e r r e s e a r c h needed  the  aliphatic  dissolution acids.  of  t h i s experiment would  shed  t o account f o r d i f f e r e n c e s  minerals  by  low-molecular-weight  6  MATERIALS AND  1.  EXPERIMENTAL DESIGN Basaltic  the  METHODS  and  Cheakamus  g r a n o d i o r i t i c samples were c o l l e c t e d from  and  Cypress  Bowl  Formations  located  C o a s t a l Mountain Range of B r i t i s h Columbia.  The  were then crushed and s i e v e d and the 0.1 mm  - 0.5  fraction  (fine-medium sand) was  Particles  the  r o c k samples mm  r e t a i n e d f o r the  i n t h a t s i z e range were c o n s i d e r e d  in  diameter  experiment.  f i n e enough t o  r e a c t c h e m i c a l l y w i t h aqueous s o l u t i o n s but c o a r s e enough t h a t l i q u i d s c o u l d be  c l e a r l y separated  centrifugation.  A l s o p a r t i c l e s i n t h a t s i z e range  the  chances  of  plugging  from them by  gravity  i n g r a v i t y columns.  and  preclude  Samples were  mixed t h o r o u g h l y t o achieve maximum homogeneity, then weighed t o 100  gms,  and  In order  leached  w i t h 400 mis  t o compare the  of a c i d per  day.  r e l a t i v e d i s s o l u t i o n powers of  o r g a n i c a c i d s i n weathering of minerals, t h r e e a l i p h a t i c a c i d s were  chosen  associated with  one  carboxyl  hydroxyl  carboxyl  and  selected. concentration To  which  are and  and  acetic Each  characterized hydroxyl  three  acidic  groups.  carboxyl,  acid  with  by  one  solution  the  number  Thus, c i t r i c  of acid  o x a l i c a c i d with carboxyl was  group  brought  two were  to  . 1M  (see T a b l e 1).  f u r t h e r evaluate  the  e f f e c t i v e n e s s of  the  acids  in  d i s s o l v i n g b a s a l t and g r a n o d i o r i t e , two c o n t r o l s o l u t i o n s were  7  Citric  Acid  Oxalic Acid  Chemical Name  2-Hydroxy propane 1,23-tricarboxylic acid  Ethanedioic  Chemical Composition  C H 0  Category  Non-volatile aliphatic  Non-volatile aliphatic  Volatile, aliphatic  Type o f Complex  5 and 6 r i n g  5 ring  Monodentate  pKa  3.14, 4.77, 6.39  1.23, 4.19  4.76  2.3  1.6  2.9  pH o f 1 0 M solution _1  6  8  6  C  Acetic Ethanoic acid  acid  2 2°4 H  C  2 4°2 H  H  I  H— C—COOH  HO  I  Structures  C  HOOC — C — O H  TABLE 1 :  0  HO  V  O  I  H—C—H  ,c  H—C—COOH H  /  I  I . I  0  OH  I  H  CHEMICAL DESCRIPTION OF CITRIC, OXALIC AND ACETIC ACID.  8  prepared - .004M HCL and d i s t i l l e d water.  This  concentration  o f HCL produces approximately the same amount o f i o n i z e d H i n s o l u t i o n (pH = 2.4) as do .1M c i t r i c = 2.9) a c i d s .  (pH = 2.3) and a c e t i c (pH  The pH of .1M o x a l i c a c i d was somewhat  lower  a t pH = 1.6 and d i s t i l l e d water much h i g h e r a t pH = 5.7. Three r e p l i c a samples of b a s a l t  and g r a n o d i o r i t e . were  leached by t h e 5 organic and i n o r g a n i c was  undertaken by batch  treatments.  and column e x t r a c t i o n  Leaching  methods.  A  summary of the experimental d e s i g n i s as f o l l o w s : EXPERIMENT  COLUMN/BATCH  PARENT MATERIAL I TREATMENT citric 1  REPLICAS  The out  I  I  1,2,3  I BASALT  1 Oxalic I  I  1  1,2,3  GRANODIORITE  1  1  1  A c e t i c HC1 I  '  1,2,3  i  ' ' H20  i citric  1—i—i—i—i—i  1,2,3  1,2,3  1  Oxalic  |—i—i  1—i—I  1—|—|  |  1,2,3  1,2,3  1,2,3  column and batch l e a c h i n g  were leached f o r one month followed  reassembled  n H20  1—|—,  1  1  1,2,3  experiments were c a r r i e d In t h e f i r s t , by d e s t r u c t i v e  of both s o l u t i o n s and weathered m a t e r i a l . were then  i HC1  1,2,3  over two d i f f e r e n t time p e r i o d s .  solutions  Acetic  samples analysis  F r e s h samples and  and leached  f o r 11 weeks.  S o l u t i o n s were removed and analyzed a f t e r week 1, 3, 5, 7, 9, and  11.  In t h i s way f r e s h s o l u t i o n s were i n t r o d u c e d  i n t o the  column and batch experiments every two weeks which not only enhanced the r a t e s of d i s s o l u t i o n but enabled c a l c u l a t i o n s of k i n e t i c features  o f the experiment.  At t h e end o f 11 weeks,  the m i n e r a l samples were a i r - d r i e d i n p r e p a r a t i o n analysis.  f o r further  9  2 .  D E S C R I P T I O N  O F  C O L U M N  E X P E R I M E N T A L  A P P A R A T U S  A N D  P R O C E D U R E  A column e x t r a c t i o n procedure was designed which u t i l i z e d the  force of gravity  t o l e a c h the m i n e r a l parent m a t e r i a l .  From t o p t o bottom the apparatus for  c o n s i s t e d o f the f o l l o w i n g  each sample: (a)  One  litre  polyethylene b o t t l e  with  tubulation i n  which t h e e x t r a c t i n g s o l u t i o n was p l a c e d . (b)  P o l y v i n y l c h l o r i d e t u b i n g t o connect  the b o t t l e t o  the sample column. (c)  A d j u s t a b l e clamp p l a c e d on the t u b i n g t o c o n t r o l flow r a t e .  (d)  Rubber stopper i n s e r t e d i n t o the top of the column. A h o l e bored  into this  stopper t o d i r e c t  t h e PVC  t u b i n g i n t o the column. (e)  Acrylic  column  25  cm  i n l e n g t h and  2.5  cm  inner  diameter t o c o n t a i n 100 gm of sample. (f)  2 mm  i n e r t g l a s s beads packed t o a depth of 2.5 cm  into  t o p o f column and r e s t i n g  on rock sample t o  promote even d i s t r i b u t i o n o f l e a c h a t e . (g)  100 gm o f crushed rock sample p l a c e d i n t o column.  (h)  Whatman a s h l e s s No.  41 f i l t e r  paper beneath rock  sample. (i)  Rubber  stopper  inserted  i n t o bottom of column t o  support sample and f i l t e r paper.  A h o l e bored  into  10  t h i s stopper d i r e c t e d an a c r y l i c tube i n t o catchment beaker. (j)  600  ml  catchment beaker w i t h  cellophane  cover  to  on a t a b l e  i n which  i n h i b i t evaporation. The  entire  assembly was  supported  h o l e s were bored t o enable c o n n e c t i n g PVC t u b i n g (from the one l i t r e b o t t l e t o the column) t o pass through. was  pulled  around each sample column and  An e l a s t i c band  attached to  nails  i n s e r t e d on a s i d e panel b u i l t on a l l f o u r s i d e s of the t a b l e . S o l u t i o n s from each sample were separated from the parent material  f o r f u r t h e r a n a l y s i s by removing the contents  the 600 ml c a t c h beaker. was  from  R e c y c l i n g of the s o l u t i o n each day  achieved by p o u r i n g the s o l u t i o n captured  i n the 600  ml  beaker back i n t o the 1 l i t r e p o l y e t h y l e n e b o t t l e r e s t i n g  on  the t a b l e .  3.  DESCRIPTION OF BATCH EXPERIMENTAL APPARATUS AND  PROCEDURE  A batch e x t r a c t i o n procedure u t i l i z e d the p h y s i c a l f o r c e of  shaking sample and  solution  the m i n e r a l parent m a t e r i a l . was  chosen t o minimize  f o r 1 hour each day t o l e a c h An a r b i t r a r y time of one  physical  or mechanical  hour  breakdown of  particles. 100 gms 500  ml  of s i e v e d g r a n o d i o r i t e and b a s a l t were p l a c e d i n  polyethylene  bottles  with  400  s o l u t i o n and s e a l e d with p a r a f i l m and No. Each day  mis  of  9 rubber  the s e a l s were removed so t h a t the  extracting stoppers. extracting  11  s o l u t i o n c o u l d e q u i l i b r a t e with C0 i n the atmosphere 2  S o l u t i o n s from each sample were separated from the  parent  m a t e r i a l by c e n t r i f u g a t i o n a t 4200 rpm i n order t o c a r r y out further In  analyses. batch  experiments  particle  size  does n o t have t h e  p o t e n t i a l t o i n t e r f e r e with l e a c h i n g r a t e s as i s t h e case i n gravity  -  column  experimental  set-ups.  I t -was  decided  t h e r e f o r e t o a l s o study, by batch procedure, t h e l e a c h i n g o f g r a n o d i o r i t e and b a s a l t which were s i e v e d and c o l l e c t e d from <.l  mm  diameter  "Granodiorite designated  particles.  Samples  <.lmm  were  designated  B" and " B a s a l t B"; Samples . 1 mm - .5 mm were  " G r a n o d i o r i t e A" and " B a s a l t A".  Furthermore, a  c r u s t - l i k e m a t e r i a l s e t t l e d on the top o f weathered a i r - d r i e d b a t c h samples f o l l o w i n g 11 weeks of l e a c h i n g . that  this  chemical  crust-like  material  might  reveal  f e a t u r e s and was t h e r e f o r e separated  of t h e sample and analyzed.  I t was thought distinctive from t h e bulk  T h i s m a t e r i a l was r e f e r r e d t o as  "crust".  4.  ANALYSES  OF  SOLUTION  EXTRACTS  AND  WEATHERED  MINERAL  PARTICLES  (a)  Solution Extracts Determination o f d i s s o l v e d Ca, Mg, Na, K, Fe, A l , and S i  ions  was c a r r i e d out with  absorption  a Perkin-Elmer Model  spectrophotometer.  3 06  To overcome p o s s i b l e  atomic anionic  12  interference, levels  a n i t r o u s oxide flame was  of Ca,  determining  levels  s o l u t i o n s was  (b)  A l and  Si.  Fe, Mg,  determined  Mineral  An Na  used  acetylene and  K.  i n determining  flame  pH  was  of the  used  in  extracting  by an Accumet pH meter, Model  810.  Residues  Chemical  and  physical  analyses  of the unweathered  and  weathered g r a n o d i o r i t e and b a s a l t i n c l u d e d the f o l l o w i n g :  X-  ray d i f f r a c t i o n (XRD), X-ray f l o r e s c e n c e (XRF), SEM e l e c t r o n microscopy) , l i g h t microscopy, EDX X-ray)  CEC  (cation  exchange c a p a c i t y ) ,  (scanning  (energy d i s p e r s i v e  exchangeable  bases,  s u r f a c e area, pH and e x t r a c t a b l e Fe, A l and S i . C i t r i c and o x a l i c a c i d c r y s t a l s and c i t r a t e and o x a l a t e salts  of K,  Na,  Mg,  K,  Fe,  l a b o r a t o r y f o r subsequent XRD  A l and  S i were prepared  analysis.  i n the  T h i s data was  used,  i n a d d i t i o n t o p u b l i s h e d data of XRD peaks f o r o r g a n o - m e t a l l i c salts,  to  assist  in  the  identification  of  secondary  precipitates.  (i)  XRD A n a l y s i s Unoriented  powder  mounts  were  prepared  for  XRD  examination of the gross m i n e r a l d i s t r i b u t i o n s .  The  sediment samples were packed i n t o a standard P h i l i p s aluminium sample h o l d e r and compressed w i t h a p i s t o n and a mechanical p r e s s . made  with  an  The d e t e r m i n a t i o n s were a l l  automated  Philips  PW  1710  Powder  13  D i f f r a c t o m e t e r u s i n g CuK & X - r a d i a t i o n w i t h a curved graphite  crystal  (002)  monochromator,  and  an  a u t o m a t i c a l l y a d j u s t i n g d i v e r g e n c e s l i t (goniometer controlled).  The  unoriented  samples were q u i c k l y scanned to  )  powder  and  mineral  (,l°2/sec) from 4.2°0  60.2°0.  XRF  Analysis  For the major elemental d e t e r m i n a t i o n by XRF, 36 mm diameter g l a s s d i s c s were prepared by f u s i n g , u s i n g 0.4 g o f sample and 3.6 g o f u l t r a - p u r e 105  Spectroflux  (Johnson-Matthey Chemicals Ltd.) c o n s i s t i n g o f  LigB^Oy, Lag0 and L i g 0 .  Before weighing, the f l u x  was  a t 500°C f o r one  3  dried  3  i n a furnace  remove absorbed water.  hour t o  The weighed f l u x and sample  were p l a c e d i n t o a p l a t i n u m c r u c i b l e and fused i n a m u f f l e furnace a t 1100°C f o r 2 0 minutes.  After  c o o l i n g the fused samples, the weight l o s s r e s u l t i n g from the removal o f i n t e r l a y e r water, o x i d a t i o n o f o r g a n i c matter and v o l a t i l i z a t i o n o f some elements, was made up w i t h S p e c t r o f l u x 100 which c o n t a i n s only Li2B4P and thus does not a l t e r t h e sample/La 7  ratio.  La i s needed as a heavy absorber i n the g l a s s d i s c s to and  i n c r e a s e the t o t a l mass a b s o r p t i o n o f the g l a s s thereby  minimize  matrix  between d i f f e r e n t samples.  absorption  effects  A f t e r adding f l u x  100,  14  the g l a s s was  r e f u s e d on a Meker burner and  i n t o an Al-mould molten  sample  on a h o t p l a t e s e t a t 400°C. flattened  with  plunger, and the r e s u l t i n g d i s c was  later  was  then  p r e s e n t e d t o the X-ray beam. PW  1400  X-ray  peripheral  a  PDT  the  11  The brass  directly  An automated P h i l i p s  f l o r e s c e n c e i n combination  digital  calculating  poured  computer  elemental  was  with used  a  for  concentrations.  C a l i b r a t i o n of the analyses was p r o v i d e d by a l a r g e number of i n t e r n a t i o n a l rock standards.  i ) SEM  and EDX A n a l y s i s  Samples t o be microanalyzed by SEM scanning  electron  microscope  were mounted on  stubs  c o l l o i d a l g r a p h i t e i n an a l c o h o l base.  painted  with  The mounted  p a r t i c l e s were then C-coated by a vacuum evaporator and observed u s i n g a Hatachi S-570 scanning e l e c t r o n microscope.  P o l a r o i d photographs of the  images  taken  were  at  electron  various magnifications  and  a n a l y s i s of the sample was c a r r i e d out w i t h a Kevex 8000 Energy d i s p e r s i v e X-ray  spectrometer.  Those  samples which were not s u b j e c t e d t o m i c r o a n a l y s i s ( i . e . , EDX)  were t r e a t e d with a Hummer g o l d s p u t t e r  coater  as  so  photographic  to  enhance  the  quality  in  the  image.  ) Photographs of mineral  samples were taken  with  a  15  Z e i s s d i s s e c t i n g microscope a t 50 x m a g n i f i c a t i o n . (v)  S u r f a c e Area S u r f a c e area was determined by t h e e t h y l e n e g l y c o l monoethyl  ether  (EGME) t e c h n i q u e  (Heilman,  M.D;  C a r t e r , D.L and Gonzales, C.L. 1965).  (vi)  Chemical Analyses C a t i o n exchange c a p a c i t y and exchangeable were  measured  by t h e ammonium  acetate  cations (pH 7.0)  method, f o l l o w i n g t h e procedure g i v e n by L a v k u l i c h (1981).  Iron, aluminum and s i l i c o n were e x t r a c t e d  by sodium pyrophosphate  (pH 10.0) (Bascomb,  1968),  a c i d ammonium o x a l a t e (pH 3.0) (McKeague and Day, 1966)  and c i t r a t e - b i c a r b o n a t e  solution  (pH 7.3)  (Weaver e t a l , 1968; Mehra and Jackson, 1960).  The  ppm  was  o f each  element  within  each  extractant  measured u s i n g atomic a b s o r p t i o n spectrophotometry on  a Perkin-Elmer  306 spectrophotometer.  These  elements were then c a l c u l a t e d as a p e r c e n t o f t h e total  sample.  The pH was determined i n both water  (Peech, 1965) u s i n g  a 1:1 mineral:water suspension, and i n 0.01 M C a C l 1965)  using  a  1:2  mineral:0.01M  CaCl  2  2  (Peech,  suspension.  PH  measurements were taken on an Accumet pH meter, Model 810.  16  LITERATURE REVIEW A.  THE  ROLE OF ORGANIC ACIDS IN WEATHERING OF MINERALS  1.  Occurence o f N a t u r a l Organic Natural  environments microbial 1986).  organic are  rainwater (IO" M)  derived  metabolism Oxalic  acids  and  and other  Acids in  from  soils  plant  canopy  and  drip  organic  and animal  (Huang  acids  and  can  i n c o n c e n t r a t i o n s as h i g h as a few  residues, Violante,  also  occur  in  micromolar  (Stumm e t a l . , Stumm and F u r r e r , 1987) .  6  freshwater  In top s o i l s ,  the presence of water s o l u b l e o r g a n i c a c i d s , such as m a l i c , malonic, and  c i t r i c , oxalic, acetic, succinic, t a r t a r i c ,  p-hydroxybenzoic a c i d s may  vanillic  reach c o n c e n t r a t i o n s as  high  as IO" M t o 10" M, o x a l a t e being the most abundant ( G r a u s t e i n , 5  1977;  3  Stevenson,  produced,  and  1982).  i n the  In fungal mats where o x a l a t e s  rhizosphere  where  root  exudates  are are  s e c r e t e d , as w e l l as l o c a l i z e d m i c r o c l i m a t e s such as c a p i l l a r y water a d j a c e n t t o a c i d s may  be  environment,  a s o i l p a r t i c l e , concentrations of organic  even much higher. the  average o f 7 mg/g  tcp  l a y e r of  In one a  forest  study soil  of a natural contained  o x a l a t e , with the o x a l a t e c r y s t a l s  t o f u n g a l hyphae demonstrating  an  adhering  the source o f the o r g a n i c a c i d  ( G r a u s t e i n e t a l . 1977). Ca-  and  lichen t h a l l i  Mg-oxalate  crystals  grown on b a s a l t and  have  also  serpentine  been  found  (Jones  in  et a l .  17  1980; Wilson e t a l . 1981).  The presence of o x a l i c and  a c i d s i n the weathering c r u s t o f by t h i n l a y e r chromatography Stevenson  (1967)  has  sandstone was  citric  demonstrated  (Eckhardt 1978) . reviewed  the  distribution  pedogenic a c t i v i t y of o r g a n i c a c i d s i n s o i l .  and  These a c i d s are  c h e m i c a l l y p o l y f u n c t i o n a l i n t h a t they c o n t a i n more than carboxyl  group  hydroxyl  groups  inorganic  ions.  (e.g. o x a l i c )  o r c a r b o x y l w i t h one  (e.g. c i t r i c ) A chelate  and  can  complex  form  forms  o r more  chelates  when two  one  with  o r more  c o o r d i n a t e p o s i t i o n s about the metal i o n are o c c u p i e d by donor groups o f a s i n g l e l i g a n d t o form an i n t e r n a l r i n g s t r u c t u r e . High-molecular-weight  o r g a n i c polymers,  such  as  fulvic  and  humic a c i d s , although l e s s completely c h a r a c t e r i z e d , possess carboxyl,  h y d r o x y l and  amide groups  complexes  with  (Mortenson,  Caroll  metals  and  also  1963).  form Konova  chelated (1961),  (1970), and McKeague e t a l . (1986) have d i s c u s s e d the  v a r i o u s r o l e s or o r g a n i c compounds i n pedogenesis.  2.  Organic A c i d s and S o i l The  mineral science. concept, thought and  awareness  of  an  Weathering interaction  between  organic  and  components emerged i n the v e r y e a r l y years of Long b e f o r e Dokuchaiev soil  organic acids,  soil  formulated h i s p e d o l o g i c a l  including  humic  acids,  were  t o p l a y an important r o l e i n the d i s s o l u t i o n o f rocks  minerals.  Sprengel  i n 1826  o r g a n i c a c i d s i n m i n e r a l weathering  suggested  a  (Tan, 1986),  key  role  of  f o l l o w e d by  18  Kindler  i n 1836 who  reported  the bleaching  of  (Bloomfield,  1981).  sands around decomposing r o o t s continues  ferruginous Evidence  t o accumulate t o t h i s day i n d i c a t i n g t h a t  organic  a c i d s , both aromatic and a l i p h a t i c , a c c e l e r a t e d e g r a d a t i o n o f rocks  and m i n e r a l s  chelating  due t o t h e i r i n h e r e n t  capacity  a c i d i t y as w e l l as  (e.g. Huang and K e l l e r , 1970; Huang and  Kiang 1972; Boyle e t a l . 1974; Razzaghe-Karimi 1974;  Singer  and Navrot 1976; S c h n i t z e r and Kodama, 1976; and Pohlman and M c C o l l 1988) . Debate  as t o t h e r e l a t i v e  importance  of a c i d i t y vs.  c h e l a t i o n i n promoting d i s s o l u t i o n o f minerals reviewing  i s evident i n  the l i t e r a t u r e of s o i l science j o u r n a l s .  In 1967,  S c h a l s h a e t a l . s t u d i e d the e f f e c t o f complexing agents on the solubilization "the  formation  simultaneously sole  o f Fe from g r a n o d i o r i t e and p o s t u l a t e d  or  of  metal  complexes  may  mechanism  responsible  for  theretofore  a t t r i b u t e d exclusively to H ions."  year  et  a l . (1967)  chelating a b i l i t y  observed  of a biogenic  removed from b i o t i t e .  place  Ca from C a - r i c h  that  some  effects  In t h e same  the g r e a t e r  the  a c i d t h e more Fe and A l i t  Huang and Kiang  a c i d t o be more e f f e c t i v e than other and  take  w i t h a c i d a c t i o n , o r t h a t c h e l a t i o n may be t h e  major  Boyle  that,  (1972) found  citric  acids i n extracting A l  p l a g i o c l a s e , presumably because o f i t s  g r e a t e r complexing a b i l i t y . increase  the t o t a l  weight  distilled  water by  factors  S t r o n g l y complexing o r g a n i c a c i d s of clay  minerals  o f 5 t o 75  dissolved  by  (Huang and K e l l e r ,  19  1971), and may a l t e r the r a t i o o f S i t o o t h e r metals, n o t a b l y A l and Fe, d i s s o l v e d from some s i l i c a t e m i n e r a l s (Huang and Keller,  1970) .  dependent  Indeed,  the  A l ion species  r e l a t i v e d i s t r i b u t i o n of  i n aqueous s o l u t i o n  pH-  i s markedly  a l t e r e d by A l - S a l i c y l a t e complexes w i t h i n the pH range 1.5 t o 7.5  (Huang and K e l l e r , More r e c e n t l y ,  1972).  Pohlman and M c C o l l  (1986) a n a l y z e d the  moles o f metal r e l e a s e d from a s o i l by lO'^M c i t r i c a c i d a t pH 3.25 of  and 5.65.  By c a l c u l a t i n g the r a t i o o f number of moles  c a t i o n s r e l e a s e d t o H* i o n s consumed d u r i n g t h e  process,  they  concluded  that,  "the  effect  of  leaching  H  on  +  the  d i s s o l u t i o n p r o c e s s was minimal and d i s s o l u t i o n o f metals from the s o l i d phase was mainly by s h i f t i n the a n i o n i c s p e c i e s of citric from  acid."  However, Manley  t h e i r ^weathering  and  experiments  Evans  (1986), concluded  that  the  amount  of  Al  r e l e a s e d from f e l d s p a r s by the o r g a n i c a c i d s appeared t o be r e l a t e d more t o t h e i r a c i d i c s t r e n g t h s than t o t h e i r to  form  formation would  complexes. were  They  o f paramount  pointed  out  importance  that  if  ability "complex  i n dissolution,  have been expected t h a t p r o t o c a t e c h i n i c , g a l l i c ,  it and,  p a r t i c u l a r l y , c a f f e n i c a c i d would have e x t r a c t e d more A l than the  observed amounts".  C o n c u r r e n t l y Tan,  (1986),  t h a t humic a c i d s w i t h both c a r b o x y l and p h e n o l i c  reported  functional  groups a f f e c t m i n e r a l d i s s o l u t i o n by both the a c i d i c e f f e c t and complex f o r m a t i o n . aliphatic  acids  He maintained, however, t h a t simple  including  oxalic  acid  affect  mineral  20  decomposition effect". in  "generally  more through  the  acidic  (H*  ions)  Bloom and E r i c h (1987) found t h a t the type of anion  s o l u t i o n determined  dissolution.  the  rate  and  mechanism  In s o l u t i o n s c o n t a i n i n g  i o n s not  of  gibbsite  specifically  adsorbed (e.g., NO~and SO? ), p r o t o n a t t a c k of the s u r f a c e the r a t e - d e t e r m i n i n g  step.  was  In s o l u t i o n s c o n t a i n i n g phosphate  which forms i n n e r sphere complexes, a n i o n a t t a c k predominated and  the  Finally,  rate  the  reaction  was  released  by  thereby p r o v i d i n g  hydrogen  dependent a c i d s may  ion attack  et a l . 1967).  r e a c t i o n c o n t i n u a l l y s h i f t s t o the  on  silicate  and  over t h a t  of a  congruent  extended  minerals  of s o l u b l e ions can  soluble  r i g h t of e q u i l i b r i u m  Also,  concentrations  remove  the  where p r e c i p i t a t i o n products b u i l d up. of  pH.  In t h i s way  r a t e of d i s s o l u t i o n i s i n c r e a s e d  dissolution  on  a s i n k t o keep s p a r i n g l y  metals i n s o l u t i o n (Schalscha  the  not  i t must be remembered t h a t o r g a n i c  metals a l r e a d y minerals  of  is be  the  b u i l t up  system  domain of as  before  higher a  new  phase i s formed.  b.  Geochemistry and  Weathering  Geochemists have r e c e n t l y begun t o apply  the p r i n c i p l e s  of chemical k i n e t i c s t o mineral weathering r e a c t i o n s o c c u r r i n g in  soils.  different  Most of the work done has composition  other minerals  although  have been s t u d i e d  involved  pyroxenes, (Berner,  feldspars  amphiboles,  1981;  Lasaga,  of and  1981;  21  Holdren and Speyer, 1985; Chow and W a l l a s t , case o f f e l d s p a r s , many experimental r a t e s have r e s u l t e d i n c o m p i l a t i o n s  1985) .  studies  In the  of hydrolysis  of rate c o e f f i c i e n t s f o r  d i f f e r e n t experimental c o n d i t i o n s (Helgeson e t a l . , 1984), y e t the  actual  clearly  mechanism  defined  of feldspar  d i s s o l u t i o n i s s t i l l not  (Coleman and D e t h i e r ,  1986).  Some  general  t h e o r i e s however have a r i s e n from mineral d i s s o l u t i o n s t u d i e s . In many d i s s o l u t i o n experiments t h e r e l e a s e o f s i l i c o n and  alkali  ions  are l i n e a r  functions  o f t h e square r o o t o f  time and t h i s has been c h a r a c t e r i z e d as f o l l o w i n g " p a r a b o l i c " r a t e laws. behaviour through 1967;  Some r e s e a r c h e r s  have a t t r i b u t e d t h i s  t o t h e d i f f u s i o n o f ions  an ever  thickening  from  parabolic  the fresh  secondary p r e c i p i t a t e  Helgeson, 1971), o r through a leached  mineral (Wollast,  l a y e r formed on  the parent m a t e r i a l (Luce e t a l . , 1972; Paces, 1973; Busenburg and  Clemency, 1976). From t h e work o f P e t r o v i c  (1983) i t i s l i k e l y  (1976) and Schott  t h a t t h e s t r u c t u r e o f a hydrous  oxide l a y e r , s i m i l a r t o t h a t o f aluminum hydroxides on  mineral  surfaces  In  t h e leached  layer  hydrated  surface layer.  nonstoichiometric exchangeable  ferric forming  i s not p r o t e c t i v e towards d i s s o l u t i o n . hypothesis,  mobile elements such as a l k a l i s mineral  & Berner  and leads  cations,  i s thought t o occur a t t h e  t o t h e formation  Diffusion residuum  p r e f e r e n t i a l leaching of  of  then  while  of a residual  reactants controls  the  through the release  leached  silicate  this of or  22  a l u m i n o s i l i c a t e framework d i s m a n t l e s a t a slower r a t e . l a y e r b u i l d s up, steady s t a t e from the  the  rate  rate-limiting controlled Holdren  step  the  rate  a  silica  cations  from  F i n a l l y , o t h e r s have argued t h a t the  (Lagache,  Berner,  1979;  1976;  Petrovic  Holdren,  ( G a r r e l s and  et  1983).  e n v i s i o n s weathering as a two stage p r o c e s s : of H* f o r a l k a l i s  of  i s , i n contrast to d i f f u s i o n , a  reaction  and  r a t e of removal o f  keeps pace w i t h  deeper w i t h i n the s o l i d .  the  of d i s s o l u t i o n decreases u n t i l  i s reached when the  surface  As  surface-  al.  This  1976; theory  a r a p i d exchange  Howard, 1959)  followed  by  the  r a t e determining step c o n t r o l l e d by the detachment of s i l i c a t e and  aluminate u n i t s from the  and  Helgeson,  constant,  as  1982). long  as  The  crystalline rate  parameters not  d i s s o l u t i o n should  such  as  pH,  surface  Schott and Berner (1983) s t u d i e d the mechanism of i r o n  protonated  weathering  layer  did  not  t h i c k n e s s d u r i n g t h e i r experiments. was  Helgeson,  noted  continue  to  that  surface  inner  a t the  surface.  same r a t e t h a t Accordingly,  the  the  grow  in  They concluded t h a t t h i s  most l i k e l y a r e s u l t of l o s s by d i s s o l u t i o n a t the  outer its  and  and  area,  1982).  hypothetical  (Aagaard  be  concentration  d i s s o l u t i o n during  change  (Aagaard  ligand  silicate  do  of  framework  i t grew by  layers  H* a t t a c k  non-linear  at  k i n e t i c s at  the b e g i n n i n g of most experiments are a t t r i b u t e d t o the r a p i d d i s s o l u t i o n of h y p e r f i n e  particles,  as  i t has  i n experimental systems t h a t S i i s r e l e a s e d  been observed  from f e l d s p a r i n  a l i n e a r f a s h i o n f o l l o w i n g removal of h y p e r f i n e s  by HF-H -S0 2  4  23  treatment  (Holdren and Berner, 1979).  U n t i l very  r e c e n t l y the tendency i n the  literature  has  been t o c o n s i d e r t h a t the r a t e l i m i t i n g step d u r i n g  silicate  dissolution  and  hypothesis  is  related  to  surface  of d i f f u s i o n c o n t r o l has  phenomenon,  been commonly  the  discarded  because of the f a i l u r e t o i d e n t i f y a r e s i d u a l l a y e r w i t h aid  of  modern  photoelectron microscopy  spectroscopic  spectroscopy  (SEM).  methods,  (XPS)  or  However, as p o i n t e d  such  as  scanning out by  X-ray  electron  Berner e t a l .  (1985), i f d i s s o l u t i o n occurs along deep c r a c k s , tubes, and so on, t h a t i n t e r s e c t o n l y a s m a l l p o r t i o n o f the s u r f a c e , XPS, depth, these  etch  holes  mineral  which samples a l a r g e s u r f a c e area t o a  is likely  to miss c a t i o n d e p l e t i o n s on  pits.  Hence,  the  failure  the  to  the  small  walls  detect  of  cation  d e p l e t i o n does not prove a b s o l u t e l y t h a t d i s c o n t i n u o u s a l t e r e d layers  are  presented silicate which  likely  In  fact,  Petit  e t a l . (1987) have  minerals  using  direct  providing  a resonant  hydrogen points  of  nuclear  profiling. access  reaction The  surface  f a c i l i t a t e the d i f f u s i o n of molecular  crystal work.  formed.  the f i r s t d i r e c t evidence of s u r f i c i a l h y d r a t i o n of  allows  defects,  had  not  thereby  enhancing  reactions with  (RNR),  presence energy,  the  silicate  a l r e a d y been detected d u r i n g the d i s s o l u t i o n of  Eggleton  and and  was  invoked  Boland  by  (1982) as  Veblen the  and  would  water i n t o the  I t should be added t h a t d i f f u s i o n of m o l e c u l a r  glasses  of  Busek  controlling  netwater  silicate  (198 0) step  for  and the  24  weathering of pyroxenes. I t may  be summarized t h a t indeed an a l t e r e d s u r f a c e l a y e r  develops on m i n e r a l s still  exposed t o s o l u t i o n s .  unanswered concerns the  The  only  rate-determining  question  step  or  the  k i n e t i c s of d i s s o l u t i o n . At any r a t e , i f i t i s t r u e t h a t f o r most s l i g h t l y s o l u b l e minerals at the  the  r a t e of d i s s o l u t i o n i s c o n t r o l l e d by  surface  (with or without a leached  reactions  layer), this  rate  w i l l depend on the c o o r d i n a t i v e i n t e r a c t i o n s t a k i n g p l a c e these s u r f a c e s .  F u r r e r and  Stumm  (1983) have proposed  on  that  r e a c t i o n r a t e s c o n t r o l l i n g d i s s o l u t i o n of most hydrous oxides and aluminum s i l i c a t e s simply depends on the c o n c e n t r a t i o n s p e c i e s i n t e r a c t i n g w i t h the s u r f a c e . the  d i s s o l u t i o n rate  depended d i r e c t l y and  on  the  presence  of 5-A1 0 2  on both the  concentration of  oxalate,  Furthermore i t was  3  in  T h e i r study showed t h a t  d i l u t e acids  extent  of s u r f a c e salicylate,  of s u r f a c e  (pH  protonation  citrate  and  of two  benzoate.  e f f e c t of the  became superimposed on t h a t of s u r f a c e p r o t o n a t i o n . t h e r e f o r e be  2.5-6)  complexes formed i n -the  concluded t h a t the  d i s s o l u t i o n r a t e can  of  considered  t o be  The  ligand total  composed  or more a d d i t i v e r a t e s :  RTOT  =  RH  +  R = t o t a l r a t e of d i s s o l u t i o n i n mol  m"  J  h"'  R „ = r a t e o f proton-promoted d i s s o l u t i o n R,.= r a t e of l i g a n d promoted d i s s o l u t i o n I t should  be noted t h a t the i n c r e a s e i n weathering r a t e  25  of 5-Al 0 upon i n c r e a s e i n p r o t o n c o n c e n t r a t i o n was n o t l i n e a r 2  3  but r a t h e r p r o p o r t i o n a l t o [H*] t o t h e 0.4 power.  Many other  common m i n e r a l s have a l s o been r e p o r t e d t o undergo f r a c t i o n a l order d i s s o l u t i o n i n a c i d s , (eg. K - f e l d s p a r 1967;  G r a n d s t a f f , 1977, and S c h o t t e t a l . ,  [H*] ) ; W a l l a s t , 033  1981).  Grandstaff  (1986) r e p o r t e d t h a t r e a c t i o n r a t e s f o r f o r s t e r i t i c are  first  order  approximately activity. ligands  series  respect  to  hydrogen  activity  and  p r o p o r t i o n a l t o t h e square r o o t o f f r e e - l i g a n d  He a l s o comments on t h e mechanism by which o r g a n i c may  According  with  olivine  influence  the d i s s o l u t i o n  rate  t o t r a n s i t i o n s t a t e r e a c t i o n theory,  of r e v e r s i b l e reactions occurs,  of  olivine.  a r e a c t i o n or  giving rise  a c t i v a t e d complex (Aagaard & Helgeson, 1982).  to  an  The a c t i v a t e d  complex o f undetermined s t o i c h i o m e t r y , may then decompose t o yield  reactants  (reverse r e a c t i o n ) o r products  s o l u t i o n (forward r e a c t i o n ) .  Organic  dissolved i n  l i g a n d s adsorbed on t h e  s u r f a c e o f t h e m i n e r a l may form m e t a l - o r g a n i c  complexes with  i o n s i n t h e a c t i v a t e d complex, d e s t a b i l i z i n g i t and p r o v i d i n g an a l t e r n a t i v e pathway f o r decomposing t h e a c t i v a t e d complex. The  metal-organic  complexes then  desorb t o y i e l d  dissolved  products. The concepts g i v e n f o r d i s s o l u t i o n o f hydrous oxides have been  extended  Stumm, 1987). the  t o t h e weathering  (Wieland  and  Hydrogen ions and l i g a n d s may a s s o c i a t e with  octahedral  sheets.  of k a o l i n i t e  Wieland  (Al-bearing)  or  tetrahedral  and Stumm  (1986),  found  that  (Si-bearing) o x a l a t e and  26  s a l i c y l a t e accelerated the d i s s o l u t i o n r e a c t i o n o f k a o l i n i t e through  attack  (slower) the  of the A l centers.  This  facilitated  the  detachment o f t h e A l s p e c i e s , which i s f o l l o w e d by  ( f a s t e r ) detachment o f the s i l i c a Robert  (1970),  and Boyle  units.  e t a l . (1974)  have  shown  e x p e r i m e n t a l l y the d r a s t i c e f f e c t o f o r g a n i c complexing agents on micas and micaceous c l a y s .  Not o n l y t h e i n t e r l a y e r and  t e t r a h e d r a l A l , but even a c o n s i d e r a b l e p a r t o f t h e aluminum of was  t h e o c t a h e d r a l l a y e r was complexed. completely  destroyed  as  the  The sheet s t r u c t u r e constituents  became  s o l u b i l i z e d o r amorphous. Recent work i n t h e f i e l d  o f geochemistry  has t h e r e f o r e  helped c l a r i f y t h e debate on t h e r e l a t i v e importance o f proton v s . l i g a n d weathering o f a l u m i n o s i l i c a t e s . ligand  facilitates  aluminum o r r a i s e s solution  breakdown  the concentrations  thereby,  dissolution,  through  extending  the  attack  of octahedral  o f complexed domain  i t seems c e r t a i n both proton  can occur s i m u l t a n e o u s l y  Whether o r not t h e  of  ions i n  congruent  and l i g a n d a t t a c k  and not one e x c l u s i v e o f t h e o t h e r .  B. WEATHERING AND THE FORMATION OF PRECIPITATION PRODUCTS Weathering o f rocks  and m i n e r a l s  spectrum  of p r e c i p i t a t i o n  solution  exceed  products  saturation.  i n t e r a c t with organic  These  may r e s u l t as  ions  i n a vast  brought  inorganic  ions  into also  ions and depending on such f a c t o r s as  27  charge  and  molar  ratios  of the  c o n s t i t u e n t i o n s , may  s o l i d s o f v a r y i n g degree of c r y s t a l l i n e o r d e r .  form  Much of the  r e s e a r c h s t u d y i n g these p r e c i p i t a t i o n products has focused on the f o r m a t i o n of s e s q u i o x i d e s due t o t h e i r common occurrence in soils.  I t was  a n t i c i p a t e d t h a t due  t o the h i g h  affinity  of o r g a n i c a c i d s f o r Fe and A l , s e s q u i o x i d e development might occur  i n the  undertaken  Batch  and  therefore  Column of  experiments.  the  literature  A  study  was  pertaining  to  s e s q u i o x i d e development  1 . Forms o f S e s q u i o x i d e s a) Fe o x i d e s Fe  oxides,  oxihydroxides  and  hydroxides  (collectively  r e f e r r e d t o as Fe oxides) are among the most common m i n e r a l s formed d u r i n g rock weathering. ( g o e t h i t e , hematite, and,  additionally  They v a r y i n m i n e r a l s p e c i e s  l e p i d o c r o c i t e , maghemite,  ferrihydrite)  f o r any m i n e r a l , i n c r y s t a l l i n i t y  and A l -  f o r Fe s u b s t i t u t i o n i n the s t r u c t u r e . A l l the parameters r e f l e c t the weathering The  various  Fe  may  environment. oxides  with  a  high  specific  surface  p r o f o u n d l y i n f l u e n c e both chemical and p h y s i c a l p r o p e r t i e s of soils and  (e.g. b u l k d e n s i t y , p o r o s i t y , s t r u c t u r e , s u r f a c e charge  anion  retention)  (Jou,1977).In  fact,  i t i s now  widely  b e l i e v e d t h a t oxides of Fe and A l i n s o i l s can p r o v i d e many more s i t e s  f o r a d s o r p t i o n of a c i d i c o r g a n i c substances  can c l a y s i n c l u d i n g s m e c t i t e s ( P a r f i t t e t a l . 1977).  than  28  Forms and synthetic  formation  environments  of Fe oxide m i n e r a l s  i n natural  and  have  by  and  been  reviewed  Oades  Townsend (1963), and more r e c e n t l y by Schwertmann and (1977), and  Sposito  Among the found  Fe  in soils  Taylor  (1984). compounds g o e t h i t e  as  i t i s the  (FeOOH) i s most  most thermodynamically  often stable  ( S p o s i t o , 1984). In the presence of Fe-complexing l i g a n d s t h a t inhibit  crystallization,  (Fe 0 . 2Fe00H. 2 . 6H 0) 2  3  may  2  however,  precipitate  ferrihydrite  from  soil  solution  ( S p o s i t o , 1984), and even the c r y s t a l l i z a t i o n o f f e r r i h y d r i t e may  be o b s t r u c t e d by the a d s o r p t i o n of s o i l o r g a n i c matter on  i t s surface  (Schwertmann, 1966).  Clearly  the  presence  directs  the  degree.  Schwertmann  number  of  transformations  low  goethite  (1966) ,  molecular  hydroxy-carboxylic and  of  from  hydroxy-carboxylic  organic of  Fe  freshly  oxides  investigated  weight  a c i d s on  ligands  the  to the  aliphatic  a  compounds  solution  remarkable  e f f e c t s of  carboxylic  crystallization  precipitated  (polybasic)  in  of  and  hematite  ferrihydrite. (e.g.  a  citric  The acid)  i n h i b i t e d c r y s t a l l i z a t i o n whereas the non-hydroxy c a r b o x y l i c acids  (e.g. o x a l i c acid) d i d  not.  Furthermore, F i s c h e r and Schwertmann (1975), demonstrated that  the  containing  addition  of  ferrihydrite  crystallization  oxalic  acid  (at  6  pH  to and  an  aqueous  70°C)  system  favoured  of hematite over t h a t of g o e t h i t e .  It  the was  suggested t h a t o x a l a t e a c c e l e r a t e d the n u c l e a t i o n of hematite  29  c r y s t a l s by a c t i n g as a template, w i t h Fe-Fe d i s t a n c e s i n Feo x a l a t e (0.56nm) b e i n g s i m i l a r t o those i n hematite On  the  o t h e r hand, where c i t r i c  acid  provided  (0.54  the  nm).  organic  l i g a n d , o x i d a t i o n of F e - c i t r a t e y i e l d e d pure g o e t h i t e . In  addition  to differences  i n type  of o r g a n i c  d i f f e r e n c e s i n c o n c e n t r a t i o n p l a y a key r o l e on which  iron  oxide w i l l  form. Schwertmann  ligand,  determining  (1986),  concludes,  "the h i g h e r the c o n c e n t r a t i o n of o r g a n i c compounds compared w i t h the  r a t e o f r e l e a s e of Fe  from  primary  silicates,  g r e a t e r the p r o b a b i l i t y t h a t g o e t h i t e w i l l be the  the  dominating  or o n l y f e r r i c oxide formed." I f the r a t e of Fe supply i s h i g h along  with  higher  concentrations  of  organic  matter,  f e r r i h y d r i t e w i l l form. At s t i l l h i g h e r o r g a n i c matter content a p r e c u r s o r of f e r r i h y d r i t e o f t e n occurs and can be c o n s i d e r e d a young metastable  Fe-oxide of low s t r u c t u r a l order and h i g h  s u r f a c e a r e a . I t s t r a n s f o r m a t i o n t o more s t a b l e forms may considerably  retarded  by  adsorbed  (Schwertmann, 1985). F i n a l l y , content, a l l the Fe may  silica  and  organics  even a t h i g h e r o r g a n i c  matter  be o r g a n i c a l l y complexed such as i n  "0" h o r i z o n s or i n peaty environments and no more Fe w i l l be formed  be  oxides  (Schwertmann, 1988).  As a r e s u l t o f such s t u d i e s the h e m a t i t e - g o e t h i t e r a t i o i n s o i l s has been used t o d i s c e r n the C-regime and, the c l i m a t e .  i n turn,  F i g u r e 1 summarizes the p o s s i b l e pathways of Fe  oxide f o r m a t i o n under near pedogenic c o n d i t i o n s . I t should be noted however t h a t amorphous p r e c i p i t a t e s or g e l s of Fe, i n  30 fast  hydrolysis  • l i d o t i o n of organic  ligands  d i s I 6 Iw* Jon  ^  ilow  hydrolysis,  ( pro -  otidoliow  dissolution  COj  FERRIHYDRITE  • procipif alien  hy  roorrongomsnl  dominonfly  J  of  dohydrof ion •  organic  by c o m p U i i o n )  ligowds  reduction  o i i d o f ion  • SIDERITE  d « h y d r o l i o n , lh«n o i i d o l i o n  prvcipifofien  Figure 1:  Fr 3 * r  •iidofion  j.  • { F ^ ' F e " HYDROXY SALT  (llew) J  (fasf),  I I I I \  -—SLEPIOOCHOCITE  Ihon part, dohydration lien  >  Possible pathways of i r o n oxide formation under near pedogenic c o n d i t i o n s . Source:  Schwertmann, and Taylor, 1977.  -6 r-\ Fe(OH)3 (amorp)  Fe(OH)  3  (Soil-Fe)  •y-F*203 (maghemite)  •y-FeOOH (lepidocrocite)  Source:  Figure 2:  The a c t i v i t y of F e  3 +  Lindsay, 1979.  maintained by Fe(III) oxides and s o i l - F e .  31  association detailed base  with  organic  and  inorganic  anions,  are  i n the diagram. To date t h e r e appears t o be  line  data  in  soil  science  literature  not  little  chemically  c h a r a c t e r i z i n g such g e l s .  b) A l o x i d e s Al  i n s o i l s o l u t i o n s and freshwater undergoes h y d r o l y s i s  and may  g i v e r i s e t o p r e c i p i t a t e d A l h y d r o x i d e s (Hsu, 1977).  The p r e c i p i t a t e s  may  crystallize  into  3 polymorphs,  namely  b a y e r i t e , g i b b s i t e or n o r d s t r a n d i t e depending on t h e r a t e o f p r e c i p i t a t i o n , pH of the system, c l a y s u r f a c e and n a t u r e and concentration  of  inorganic  anions  (Hsu,  1977).  Also  oxyhydroxides w i t h two polymorphs d i a s p o r e and boehmite  the may  form. The mechanisms governing t h e i r development s t i l l obscure. A l can a l s o replace  Fe *.  widespread i n s o i l s In  the  e n t e r the s t r u c t u r e o f Fe * oxides and 3  Substitution  3  of  Al  for  Fe  (Schwertmann and T a y l o r ,  presence  remain  of  silicic  acid  which  appears  to  be  1977). has  a  strong  a f f i n i t y f o r A l (Luciak and Huang, 1974), f u r t h e r h y d r o l y s i s and p o l y m e r i z a t i o n of t h e 0H-A1  polymers i s r e t a r d e d . These  counter p o l y v a l e n t anions tend t o l i n k 0H-A1 polymers t o g e t h e r but  i n d i s t o r t e d arrangements. Similarly,  many o r g a n i c a c i d s promote the f o r m a t i o n of  p r e c i p i t a t i o n p r o d u c t s o f A l which are n o n - c r y s t a l l i n e t o Xrays  (Huang and V i o l a n t e ,  1986). As i l l u s t r a t e d  i n a study  32  u s i n g c i t r i c a c i d (Kwong and Huang, 1975,1977), the o c c u p a t i o n of  the c o o r d i n a t i o n s i t e s of A l by c i t r a t e  water  molecules,  disrupts  the  hydroxyl  ions,  bridging  i n s t e a d of mechanism  i n d i s p e n s i b l e f o r the f o r m a t i o n of hydroxy-Al polymers. I t was found i n t h i s study t h a t as l i t t l e as 1 uM c i t r i c a c i d a l t e r e d the p r e c i p i t a t i o n behaviour of A l . Due  t o s t e r i c f a c t o r s , the p e r t u r b i n g l i g a n d s occupying  the c o o r d i n a t i o n s i t e s of A l d i s t o r t the arrangement of the unit  sheets normally  found  in crystalline  A l hydroxides  Al  Hydroxyl bridging mechanism of _». edge-Al is hampered by the citrate  as  shown below: H ,0v Al v  C-0  0 H  C-  II  -CH,  0  The a b i l i t y of o r g a n i c l i g a n d s t o d i s r u p t h y d r o l y s i s of Al  i s determined  l a r g e l y by the a f f i n i t y of the a c i d f o r A l  ( r e f l e c t e d i n the s t a b i l i t y constant) and the o r g a n i c l i g a n d to A l r a t i o  (determined by the c o n c e n t r a t i o n of a c i d ) .  2. E v o l u t i o n o f S e s q u i o x i d e s Much of t h e r e s e a r c h on  formation of s e s q u i o x i d e s  has  a r i s e n from the study of Podzol development. In p a r t i c u l a r , debate to  has  c e n t e r e d on whether s e s q u i o x i d e s are t r a n s p o r t e d  the Bj h o r i z o n by complexing  and Kodama, 1977;  o r g a n i c compounds ( S c h n i t z e r  Buurman and Van Reeuwick, 1984), or whether  33  as  short  range order  s i l i c a t e s upon which o r g a n i c  matter i s  s u b s e q u e n t l y p r e c i p i t a t e d (Farmer, 1981; Farmer e t a l . 1980; Anderson e t a l . 1982; Farmer e t a l . 1985). A summary o f these arguments sheds some l i g h t formation organic  a)  from  solution,  on t h e chemistry as a f f e c t e d  by  of  sesquioxide  t h e presence of  acids.  Inorganic  Fe-Al-Si Sols  During t h e 1970's, i t was apparent t h a t hydroxyaluminum s p e c i e s r e a c t w i t h o r t h o s i l i c i c a c i d a t pH< 5 t o g i v e  stable  sols  proto-  or  solutions;  imogolite,  since  the s o l u b l e  phase  i t s i n f r a r e d spectrum  was  termed  indicated  a  close  s t r u c t u r a l r e l a t i o n s h i p t o i m o g o l i t e (Farmer and F r a s e r , 1978; Farmer e t a l . 1977,1978,1979). ample S i 0  i n most s o i l  2  ensure t h a t when  a  imogolite  reactive  solutions  rather  aluminum  weathering o f minerals  I t i s proposed t h a t t h e r e i s (typically  10-40 ppm) t o  than aluminum h y d r o x i d e s species  i s liberated  be  formed i n the B h o r i z o n s , 2  deposited  only  by the  (Farmer, 1979).  In 1982, Anderson e t a l . concluded t h a t materials  form  from  charged  hydroxy-aluminum  cannot,  as argued  solutions silicate  by Farmer  imogolite-type  i n the f i r s t containing complex.  et a l .  (1980)  stage, can  a positively  These  solutions  simultaneously  t r a n s p o r t n e g a t i v e l y charged o r g a n i c matter except as a minor component sorbed on the p o s i t i v e c o l l o i d . be  present  almost e n t i r e l y  I r o n was s t a t e d t o  as a separate oxide phase,  with  34  v e r y l i t t l e of i t i n c o r p o r a t e d i n t o i m o g o l i t e type phases. The idea  that  Fe  and A l are  complex was  based  ratio  horizons  in B  extracted than  1%  2  about 20% of  Schnitzer affinity  on  the  not  the  combined  in a single  findings that  l i e s between 1.5 of the  inorganic  although  acid  o x a l a t e - e x t r a c t a b l e A l , but  less  Fe.  2.0,  A l : Fe  acetic  oxalate-extractable  and  the  Also  Kerndoff  and  (1980), showed t h a t humic a c i d s have a much g r e a t e r for hydroxy-ferric  species  s p e c i e s i n a c i d s o l u t i o n s , s o i t was  than  for  aluminum  ion  argued t h a t any mechanism  t h a t generates f e r r i c s p e c i e s , even i n low c o n c e n t r a t i o n would likely  form f e r r i c o r g a n i c r a t h e r than i n o r g a n i c  However,  Farmer  s y n t h e s i z i n g a t pH 4.5 with  Fe: A l  molar  and  Fraser  (1982)  species.  succeeded  in  and  5.0  a s t a b l e Al 0 -Fe 0 -Si0 -H 0 s o l  ratios  up  to  2  1.5  3  2  (wt/wt)  3  2  2  after  which  s t a b i l i t y decined r a p i d l y . T h e s e r e s u l t s p o i n t e d out t h a t mixed Fe-Al  hydroxide  sols,  could  transport  Al  with  or without  incorporated  Fe  i n podzols  and  and  constancy i n o x a l a t e e x t r a c t s from podzol  silica,  account B  2  for  the  of  the  horizons  A l : F e r a t i o s of 1.5-2.0. Hydroxy-Fe s p e c i e s structures  analogous  and  to  ortho-silicic  imogolite  acid  (McBride  et  do  not  form  al,  1984),  a l t h o u g h Fe * has been shown to i n t e r a c t with monomeric  silicic  3  acid  Si(0H)  relatively  4  in  stable  dilute  acid  FeSiO (OH) * 2  3  aqueous complexes  solutions (Weber  and  to  form  Stumm,  1965). T h i s complex i s monomeric a t pH<3.0 and both monomeric and  polymeric  between  between  pH  3.0  and  6.0  (Olsen  and  35  Omelia,  1973).The extent  imogolite/proto-imogolite McBride  o f Fe s u b s t i t u t i o n f o r A l w i t h i n structures  e t a l . 1984. ESR s p e c t r a  was  investigated  indicated that  by  t h e non-  c r y s t a l l i n e p r e c u r s o r o f i m o g o l i t e ( i . e . p r o t o - i m o g o l i t e ) can incorporate  Fe *; 3  Fe *  tended,  3  however,  not t o  substitute  randomly i n t h e s o l i d but segregated i n t o " c l u s t e r e d " F e * - r i c h 3  phase, even a t A l : F e  ratios  as high  as 40. Segregation  was  almost complete f o r A l : F e r a t i o s of one or l e s s . A mechanism was suggested wherby A l was e j e c t e d from an i n i t i a l l y F e - r i c h polymer, and then r e o r g a n i z e d t o form an almost F e - f r e e p r o t o imogolite allophane.  Such a process, t h e r e f o r e , c o u l d account  f o r t h e h i g h c o l l o i d a l s t a b i l i t y of the mixed AljOj-FejO^-SiOjH0 2  sols,  since  ferrihydrite  core  the d i s p e r s e d protected  phase  by  a  could  consist  proto-imogolite  of a  surface  structure. The  d e p o s i t i o n and p r e c i p i t a t i o n o f i n o r g a n i c s o l s may  occur when t h e pH r i s e s positive values, positive  charges  that  (>5 f o r p r o t o - i m o g o l i t e ) , o r when the maintain  d i s p e r s i o n a t more a c i d pH  a r e n e u t r a l i z e d by adsorbed colloids  encounter  anions,  negatively  o r when  charged  these  surfaces  (Farmer, 1979) .  b) Organic Sesquioxide The  Interaction  formation o f sesquioxides  i n the presence o f organic  substances was s t u d i e d over h a l f a century ago by Baudisch and Albrecht  (1932), who  i n v e s t i g a t e d the o x i d a t i o n  o f a mixed  36  s o l u t i o n o f f e r r o u s ions and p y r i d i n e by a i r , and by Glesmer (1938),  who  s t u d i e d the  r e a c t i o n of  NaN0  2  precipitating  a  mixed s o l u t i o n of f e r r o u s ions and hexamethylene t e t r a m i n e . In  1964  Van  Schuylenborgh r e p o r t e d t h a t one  which c o u l d account metallic  mechanism  f o r the formation of s e s q u i o x i d e s from a  organo-complex  was  that  of  hydrolysis. Giving  an  example o f a mononuclear complex, the o v e r a l l e q u a t i o n o f such a r e a c t i o n was  presented MZ""  +  m  as: nOH"  ==  M(OH)„  +  Z"  where M r e p r e s e n t s the metal  Fe or A l , n the v a l e n c y ,  organic  m  acid  equilibrium  with  basicity  constant  and  MZ"""  f o r t h i s process  the  i s then  Z the  complex.  The  g i v e n by  the  expression: K=  [ M(OH) [ MZ"""  ] [ Z- ] ro  n  ]  [ OH"]"  As soon as s o l i d M(OH) e x i s t s i n the system, [M(OH) ] becomes n  constant  and  the e q u i l i b r i u m ( h y d r o l y s i s ) c o n s t a n t  be r e p r e s e n t e d K= h  Z  can  then  by:  " [ MZ""" ] [ OH" ]" [  n  ]  and  K— [M(OH)n]  = K„  Thus an i n c r e a s e i n hydroxyl i o n a c t i v i t y ( i . e i n c r e a s e i n pH) tends  to  shift  the  equilibrium to  the  right,  eventually  c a u s i n g p r e c i p i t a t i o n of the hydroxide. Such p r e c i p i t a t i o n can be c o u n t e r a c t e d ,  a t l e a s t i n p a r t , by u s i n g an excess  of  37  organic  ligand.  In a much l a t e r study (Farmer, 1979) acid,  behaving as  a strongly  decompose p r o t o - i m o g o l i t e silicic  acid,  or  reported that f u l v i c  complexing a c i d , c o u l d  either  to give a soluble A l - f u l v a t e plus  co-precipitate  a l l Al  and  fulvate  from  s o l u t i o n , depending on the molar r a t i o of COOH: metal. S i m i l a r l y , Buurman and Van R e e u i j k (1984) , concluded t h a t metal f u l v a t e s remain s o l u b l e when undersaturated w i t h metals and  become i n s o l u b l e when the m e t a l / f u l v a t e  s a t u r a t i o n . The Fe-saturated  rises  authors a l s o noted t h a t p r e c i p i t a t e d A l  organic  biodegredation  ratio  complexes may  be  subject  to  and  subsequent  o f the o r g a n i c phase. Thus b i o l o g i c a l o x i d a t i o n  i s another mechanism whereby the i n o r g a n i c phase i s from the  to  separated  ligand.  V i o l a n t e and Huang (1984), suggested t h a t the amounts of organic  ligands present  nature and the  i n i t i a l concentration  aging  period.  In  tartrate,  citrate  and  solution  their  the  decreased d u r i n g  the  aging  tannate  or  initially  period  of  present 30  the  in solid  ligands  anions  p r e c i p i t a t e d i n the n o n - c r y s t a l l i n e A l g e l , may l i b e r a t e d upon aging,  facilitaing  They  of  also phase  such  initially be  as  in  days. V i o l a n t e  i n the. case o f  tartrate,  70-80% present  Al-oxihydroxides.  amount o f c i t r a t e  the  l i g a n d s , as w e l l  experiment more than  with  (1984) , conclude t h a t  citrate,  of the  tannate l i g a n d s  co-precipitated  observed t h a t  Huang  i n p r e c i p i t a t e s of A l depend on  and as co-  partially  the t r a n s f o r m a t i o n  of  the  38  non-crystalline  material  i n t o pseudoboehmite. However, t h e  r e l e a s e d l i g a n d s which have a s t r o n g a f f i n i t y f o r A l c o u l d be readsorbed on t h e s u r f a c e s o f t h e s o l i d phase d u r i n g The Yoldas  work o f V i o l a n t e (1973),  who  pseudoboehmite initial groups  by  and Huang a l s o  found  that  hydrolysis  4  3  7  etc.)  supports t h a t o f t h e formation  o f aluminum  noncrystalline materials (-OCH,, -OC H  during  contained  initially  the  considerable  -OR  which were r e s p o n s i b l e  noncrystalline materials  pseudoboehmite w i t h a gradual  of  alkoxides,  s t r u c t u r a l d i s o r d e r o f t h e m a t e r i a l . During t h e aging the  aging.  f o r the period,  were converted  into  l i b e r a t i o n of -OR groups.  3. E x t r a c t i o n o f Sesquioxides The s e l e c t i v e removal o f n a t u r a l l y o c c u r r i n g from s o i l s and c l a y s r e p r e s e n t s i n t h a t many c l a y minerals conditions  sesquioxides  a s e r i o u s a n a l y t i c a l problem  a r e s e n s i t i v e t o a t t a c k under the  most conducive t o d i s s o l u t i o n o f Fe, A l and S i  oxides, namely a t low pH. The methods c u r r e n t l y i n p o p u l a r use r e l y upon t h r e e e x t r a c t a n t s , namely a pyrophosphate reagent, an a c i d - o x a l a t e  reagent  and  a dithionate c i t r a t e  reagent.  Each reagent i s thought t o e x t r a c t d i f f e r e n t forms o f Fe, A l and  S i . I t must be r e c a l l e d , however, t h a t  c r y s t a l l i n e order e x i s t s , ranging  a continuum o f  from no long-range order t o  w e l l c r y s t a l l i n e , c h a r a c t e r i z e d by 3-dimensional p e r i o d i c i t y over a p p r e c i a b l e  distances  ( F o l l e t , 1965).  I t i s , therefore  d i f f i c u l t t o assess adequately t h e p o r t i o n o f t h i s continuum  39  t h a t i s b e i n g e x t r a c t e d by any p a r t i c u l a r reagent.  a) Pyrophosphate  Extraction  Pyrophosphate  reagent has been  e x t r a c t o r g a n i c compounds from s o i l  used  f o r many y e a r s t o  (Bremner and Lees, 1949) .  I t i s used a t n e u t r a l i t y (pH 7) t o l e s s e n o x i d a t i v e breakdown, or  a t an a l k a l i n e  pH  (pH 10) as o r g a n i c  matter  i s more  s o l u b l e , and c r y s t a l l i n e i n o r g a n i c Fe compounds l e s s s o l u b l e , a t t h i s h i g h e r pH (Bascomb, 1968). In r e c e n t y e a r s , e x t r a c t i o n of s o i l s w i t h 0.1M sodium pyrophosphate has been w i d e l y used t o i n d i c a t e t h e amount of Fe and A l a s s o c i a t e d w i t h o r g a n i c matter (Farmer e t a l . spodic  and p o d z o l i c  Schuppli,  1983) and as a b a s i s o f d i s t i n g u i s h i n g B horizons  1982) . Pyrophosphate  from  others  i s specific  (McKeague and f o r Fe-organic  complexes and somewhat l e s s s p e c i f i c f o r A l - o r g a n i c complexes. The S i l e v e l s e x t r a c t e d by prophosphate a r e u s u a l l y v e r y low ( P a r f i t t and C h i l d s , The  original  1988).  techniques o f e x t r a c t i n g  Fe and A l from  s o i l s by McKeague (1966) , and Bascomb (1968) d i f f e r e d by u s i n g Na- and K-pyrophosphate,  r e s p e c t i v e l y . McKeague*s method has  s i n c e been m o d i f i e d by i n t r o d u c i n g a l t e r n a t i v e t e c h n i q u e s f o r the c l a r i f i c a t i o n soil  t o be ground  Survey  Committee,  reported speeds  that  of the suspensions, and by r e q u i r i n g the t o <150um b e f o r e a n a l y s i s 1976).  In  centrifugation  progressively  1982  McKeague  (Canada and  Soil  Schuppli  f o r longer times o r a t h i g h e r  decreased c o n c e n t r a t i o n s  o f Fe and A l  40  pyrophosphate e x t r a c t s of s o i l . They concluded the Fe and A l measured i n these e x t r a c t s was form  but  present  in  the  s t r u c t u r e of  t h a t p a r t of  not i n d i s s o l v e d  suspended  minerals  thereby o v e r e s t i m a t i n g l e v e l s a t lower c e n t r i f u g a t i o n This  m a t e r i a l , amorphous  to  X-rays,  might  have  speeds.  been  fine  p a r t i c u l a t e amorphous m a t e r i a l present i n the s o i l sample, or it  might  have  formed  by  pyrophosphate e x t r a c t .  coagulation  of  solutes  in  the  Probably, because of t h i s p e p t i z a t i o n  problem, the p r e c i s i o n of r e p l i c a t e d e t e r m i n a t i o n s by u s i n g pyrophosphate reagent Digby, 1984), and  has  been found  to vary  (Loveland  comparison of r e s u l t s cannot  c o n f i d e n c e . The  continued use  of the  reagent  been q u e s t i o n e d  (Loveland and  Digby,  1984;  and  be made w i t h has  therefore  Schuppli et a l .  1983) .  b) Ammonium Oxalate Acid oxalic  o x a l a t e reagent  acid  established order.  Extraction  a t pH  (Tamm,1922), i s ammonium o x a l a t e /  3 and  this,  or  extractant for s o i l  Some  laboratories  (McKeague and Day,  use  4  similar  reagents,  materials with hour  shaking  i s an  short-range in  the  dark  1965), and some 2 hour shaking i n the dark  (Schwertmann e t a l . 1982). Borggard  (1987), has shown t h a t the r e a c t i o n i n v o l v e s the  f o r m a t i o n o f s o l u b l e complexes of Fe and A l w i t h o x a l a t e . Acid  oxalate  dissolve,  reagent  allophane,  is  known  imogolite,  to  dissolve,  ferrihydrite,  or Fe  partly and  Al  41  a s s o c i a t e d w i t h humus, l e p i d o c r o c i t e , 1982;  maghemite,  (Borggard,  Farmer e t a l . 1983) , and A l from c h l o r i t i z e d v e r m i c u l i t e  (Fordham and N o r r i s h , 1983). I n p a r t i c u l a r  this  reagent i s  recognized  for  estimating  as  being  fairly  specific  f e r r i h y d r i t e c o n c e n t r a t i o n s (Schwertmann e t a l . 1982). C h i l d s (1985), has proposed t h a t f e r r i h y d r i t e (weight  %) may be estimated  A note o f c a u t i o n : t h i s presence  of poorly  as Fh  value  crystalline  est  concentrations  = 1.7 x Fe%  (ox)  .  may be o v e r e s t i m a t e d lepidocrocite,  by t h e  magnetite o r  o r g a n i c matter complexes, a l l o f which may be a t t a c k e d by a c i d o x a l a t e (Borgarrd, 1987). A l s o the v a l u e may be underestimated where adsorbed s p e c i e s such as s i l i c a t e  inhibit  dissolution  ( P a r f i t t and C h i l d s , 1988). The  difference  between  ammonium  oxalate  e x t r a c t a b l e Fe g i v e s a measure o f c r y s t a l l i n e These  two e x t r a c t a n t s  are b e l e i v e d  and  CBD  i n o r g a n i c Fe.  t o be l e s s  d i s t i n g u i s h i n g forms o f A l and S i i n s o i l s  and  useful i n  (Borgaard,  1987),  i n f a c t Wada (1977) r e p o r t s t h a t n o n - c r y s t a l l i n e s i l i c a  i s not d i s s o l v e d by ammonium o x a l a t e .  c) C i t r a t e Bicarbonate The  o b j e c t i v e s o f t h e CBD method  determination  are p r i m a r i l y the  o f f r e e Fe oxides and t h e removal o f amorphous  c o a t i n g s and c r y s t a l s agents,  Dithionate Extraction  o f f r e e Fe oxide  f o r subsequent  physical  s o i l s , sediments and c l a y m i n e r a l s  a c t i n g as cementing  and chemical  analyses  (Mehra and Jackson,  of  1960).  42  Prerequisite  t o a good method f o r removal of  free  i r o n o x i d e s i s a reagent w i t h a h i g h o x i d a t i o n p o t e n t i a l ( i . e . a good r e d u c i n g agent). A c h e l a t i n g agent i s a l s o r e q u i r e d sequestering  Fe * and 2  Fe * i o n s . The  CBD  3  system employs sodium  c i t r a t e as a c h e l a t i n g agent, sodium b i c a r b o n a t e 7.3)  as  reduction out  a  buffer,  and  sodium  dithionate  (Mehra and Jackson, 1960). The  (NaHC0 , 3  (Na S 0 ) 2  2  for  4  pH the  reaction i s carried  f o r 15 minutes at 80°C. I t has  complete without  been claimed t h a t t h i s reagent r e s u l t s i n almost  solution  Fe  oxides,  differentiation  between  (McKeague and substituted  Day,  of  including various  c r y s t a l l i n e hematite and  1977). Magnetite and  crystal  goethite 1961;  i l m e n i t e , however are  (Walker,1983). A c o n s i d e r a b l e  interlayers  ferrihydrite, forms  1966). In a d d i t i o n t o f r e e Fe o x i d e s , A l -  by t h i s treatment ( N o r r i s h and T a y l o r ,  CBD  for  of v e r m i c u l i t e  gibbsite i s l i t t l e effected  are  Fey and not  dissolved Le Roux,  extracted  by  amount of hydroxy aluminum  chlorite i s also (Dixon and  extracted,  Jackson, 1962).  but  43  RESULTS AND  A.  Dissolution  of  Ca,  DISCUSSION;  SECTION I  Mg,  Fe,  K,  Na,  Al  and  Si  by  5  Leaching Treatments  The C  and  analysis  depicted  balance  of s o l u t i o n e x t r a c t s  graphically  calculations,  percentage solution.  of  each  each i o n o r i g i n a t e d . XRD  given  ion  T a b l e s 3 and  in  from  Appendices  B  in  Appendix  N,  estimate  the  parent  rock  brought  11  Table 5 notes the  placed  the  at  weeks of end  of  and  C.  Mass the into  4 l i s t the source m i n e r a l s from which  peak i n t e n s i t i e s i n b a s a l t i c and  following  i s g i v e n i n Appendix  weathering. Results  and  r e l a t i v e changes i n  granodiorite These T a b l e s  Discussion  minerals have been  Section  I  for  of  the  reference. For  the  sake of c l a r i t y ,  only  the  key  features  s o l u t i o n a n a l y s i s are h i g h l i g h t e d i n the f o l l o w i n g  1.  Iron and The  discussion.  Magnesium  a b i l i t y of c i t r i c a c i d and  and  Mg  to  weathering.  o x a l i c acid to chelate  depended upon the parent m a t e r i a l The  graphs  in  which was  Appendixes  B  Fe  subjected and  C  and  s t a t i s t i c a l a n a l y s i s t o the 95% c o n f i d e n c e l e v e l c l e a r l y show t h a t o x a l i c a c i d was  a more powerful e x t r a c t a n t  from g r a n o d i o r i t e than was  c i t r i c acid.  o c c u r r e d in' the d i s s o l u t i o n of b a s a l t .  o f Fe and  Mg  The complete r e v e r s a l In t h i s case  citric  44  acid  chelated  3-4  times  the  amount of  Fe  and  Mg  than  did  oxalic acid. According is  to s t a b i l i t y  constants  (See T a b l e  l e s s e f f e c t i v e than c i t r a t e as an Fe and Mg  2)  oxalate  c h e l a t o r but  i t must be remembered t h a t these v a l u e s are d e r i v e d f o r simple nutrient  solutions  for  However, the a b i l i t y be  determined  the  specific  metal  in  question.  of a l i g a n d t o c h e l a t e Fe or Mg  merely  by  its stability  cation.  Differences  between  this  constants  f o r competing ions must be  constant  constant  and  considered,  d i f f e r e n c e s i n c o n c e n t r a t i o n between F e In a d d i t i o n the pH of the s o l u t i o n w i l l  3+  cannot  for  each  stability along  with  and competing i o n s . determine the charge  of the o r g a n i c l i g a n d , and t h e r e f o r e the s t a b i l i t y of the bond between metal and  anion.  Finally,  the m i n e r a l o g i c a l makeup  of the parent m a t e r i a l as w e l l as i t s a c t i v e s u r f a c e area e f f e c t the degree of e x t r a c t i o n . be  considered  experimental First  i n more d e t a i l  factors w i l l  i n the hope of e x p l a i n i n g  of a l l , r e f e r e n c e  oxalate ligand.  i s made t o the  fact that at  pH  Mg can outcompete Fe i n s o l u t i o n f o r the  T h i s competition  F i g u r e 3 ( C l i n e e t a l . 1982).  i s graphically displayed in  In c o n t r a s t Fe can  f o r the c i t r a t e l i g a n d up t o pH  6.4  outcompete  (See F i g u r e 3 ) .  pH of the o x a l i c s o l u t i o n i n c o n t a c t with b a s a l t was, average, 4.0  the  results.  of g r e a t e r than 4.2,  Mg  Each of these  can  or h i g h e r .  Under these c o n d i t i o n s Mg,  The  on  the  which  was  r e l e a s e d from b a s a l t i n much greater' amounts than from  45  L  °9  Coi  Equilibrium Reaction  Citrate  Oxalate  Source  Ca + L = CaL Ca + H + L = CaflL Ca + 2L = CaL  4.25 8.71 7.75  2.64  (3) , (4) (2)  CaL + L = CaL  3.55 3.50 4.42 4.0 7.61 4.2 12.62 12.5 11.85  3.15 3.09 3.40  2  2  Mg + L = MgL Mg + H + L = MgHL Mg L + H = MgHL Fe + L = FeL Fe + 2L = F e L Fe + 3L = FeL Al + L = AIL AIL  + L = A1L  2 3  9.6 2  -  -  3.26 3.20 8.60 8.90 9.4 15.07 19.06 7.26 7.30 5.0  (3) , (2) (3) (2) , (3) (1) , (3) (1) , (3) (4) (4) (2) (4) (3) (3)  (4) (4) (2) (2)  Sources: (1)  Lindsay, W.L. 1979 Chemical E q u i l i b r i a i n sorts John Wiley & Sons, Inc. New York.  (2)  M a r t e l l , A.E. and Smith, R.M. 1977. C r i t i c a l s t a b i l i t y constants, Vol. 3: other organic ligands. Plenum Press, New York.  (3)  N o r v e l l W.A. 1972. In Micronutrients i n A g r i c u l t u r e , Ed Mortvedt, J . J . S o i l S c i . Soc. of Amer. Madison Wisconson, U.S.A.  (4)  S i l l a n , L.G. and M a r t e l l , A.E. 1964 S t a b i l i t y constants of metal-ion complexes. 2nd ed. Spec. Pub. no. 17. The Chemical Society, London. TABLE 2:  STABILITY CONSTANTS OF OXALATE- AND CITRATE-METAL LIGANDS  46  F i g u r e 3:  Predicted mole f r a c t i o n diagrams f o r c i t r a t e and oxalate i n a nutrient s o l u t i o n i n equilibrium with Fe(OH) (amorph). HL = sum of a l l chelated species L = f r e e ligand 3  T  Source:  Cline et a l . , 1982.  47  granodiorite, by  could  oxalate.  could  e f f e c t i v e l y suppress complexation of  Conversely, l e s s Mg  released  r e s u l t i n l e s s i o n i c competition  the o x a l a t e therefore  from  Fe  granodiorite ions  for  l i g a n d ; the complexation of Fe by o x a l i c a c i d  was  "apparently"  Ionic  more e f f e c t i v e .  competition  outcompeted o x a l a t e  between the  does  not  i n e x t r a c t i n g Mg  explain  why  citrate  from b a s a l t .  One  would  expect a l l c i t r a t e l i g a n d s i t e s t o be taken up by Fe a t pH<6.4 l e a v i n g l i t t l e or no M g - c i t r a t e by  Grandstaff  olivine, oxalate  (1986) on the  established a t pH  4.5  quantitative forsterite batch  studies,  citrate  to  analysis  forsteritic  more e f f e c t i v e than Although t h e r e  determine  the  was  percentage  i n the  determined t h a t  c o u l d c o n t r i b u t e t o the Mg  T h i s c o u l d e x p l a i n i n p a r t why of Mg  was  b a s a l t i c samples used  XRD  However, a study  d i s s o l u t i o n r a t e of  i n e x t r a c t i n g Mg.  analysis  i n the  p r e s e n t and  that  complexes.  no of  column  and  forsterite  was  released  in solution.  the c i t r i c a c i d s o l u t i o n l e v e l s  were h i g h e r than o x a l i c a c i d b a s a l t i c e x t r a c t i o n s .  On  the o t h e r hand, i t has been shown by Boyle e t a l . (1974) , t h a t o x a l i c a c i d w i l l e x t r a c t h i g h e r l e v e l s of Mg will  citric  acid.  observations by  XRD.  levels  of g r a n o d i o r i t e  This of  B i o t i t e was  Mg  extractions.  could were  explain higher  and why than  detected  from b i o t i t e than in  thin  i t s presence was the  oxalic  citric  acid  acid  section  confirmed solution  granodiorite  48  The  work  o f Manley  and Evans  (1986),  studying  acid  d i s s o l u t i o n o f f e l d s p a r s , a l s o demonstrated t h a t t h e r e l a t i v e e x t r a c t i o n powers o f c i t r i c and o x a l i c a c i d s depends upon the mineral  being  attacked.  The d i f f e r e n t  reactivity  o f the  c h e l a t i n g agents and minerals may be due a t l e a s t i n p a r t t o s t e r i c c o m p a t i b i l i t y or incompatibility.  Complexes which may  be t h e o r e t i c a l l y p o s s i b l e on the b a s i s o f s t r i c t l y c o n s i d e r a t i o n s may not form because o f geometric  chemical hindrance.  In o t h e r words the molecular a r c h i t e c t u r e may p r e v e n t groups o f a c h e l a t i n g agent from " r e a c h i n g " metal  ligand  i o n s on the  s u r f a c e o r w i t h i n the c r y s t a l l a t t i c e o f the m i n e r a l .  I t may  v e r y w e l l be t h a t d i f f e r e n c e s i n s i z e and geometry o f c i t r i c and  oxalic acid  the  mineral  i n addition to crystallographic  account  features of  f o r differences i n the d i s s o l u t i o n of  b a s a l t vs. granodiorite. As y e t t h e r e appears t o be very l i t t l e i n f o r m a t i o n i n the soil  s c i e n c e l i t e r a t u r e on c h e l a t e formation which  the  crystalline  morphological  characteristics  f e a t u r e s o f the a c i d .  of  the  connects  mineral  Analytical  with  methods o f  s e s q u i o x i d e d e t e r m i n a t i o n have r e v e a l e d t h a t o x a l a t e e x t r a c t s much o f the Fe from magnetite and i l m e n i t e but l i t t l e g o e t h i t e o r hematite,  while the converse  from  i s true of c i t r a t e  d i t h i o n i t e b i c a r b o n a t e (McKeague e t a l . 1971).  No m e c h a n i s t i c  e x p l a n a t i o n has been p r o v i d e d . Work w i t h s e s q u i o x i d e s (McKeague and S c h u p p l i , 1985) has a l s o p o i n t e d out t h a t the e x a c t a b i l i t y o f Fe from m i n e r a l s i s  49  strongly  dependent  on  particle  size.  Citrate  failed  d i s s o l v e completely c r y s t a l l i n e i r o n oxide p a r t i c l e s than 50/im. particles  I f c i t r a t e i s more e f f i c i e n t i t would  also  be  more  b a s a l t i c p a r t i c l e s than the c o a r s e r  coarser  i n attacking  effective  in  to  finer  dissolving  granodiorite c r y s t a l l i n e  particles. It  should a l s o be  m i n e r a l may and  Berner  Fe  (1983) ,  this partly  ilmenite.  Fe At  r a t i o of Fe  that  have formed  present  sequestering  parent  not  concluded  (II) r a t h e r than Fe  complexes was Perhaps  the  v a l e n c e of Fe  in  i n f l u e n c e i t s i n t e r a c t i o n with s o l u t i o n s .  complexes c o u l d only  noted t h a t  appreciable  i n t h e i r experiments  material  explains  why  on  mineral  e x t r a c t i o n powers of the two  why  in  (II) from  d e t e r m i n a t i o n of  (II) i n the b a s a l t  clarify  surfaces.  c i t r a t e i s successful  rate, a quantitative  might  since  (III) which forms strong c i t r a t e  i n s o l u t i o n and  (III) t o Fe  Schott  Fe-citrate  (III) from hematite but not the Fe  any  the  and  t h e r e was  the  granodiorite a  reversal  in  acids.  F i n a l l y , the pH of the e x t r a c t i n g s o l u t i o n must be taken into  account  weathering  (See  granodiorite  throughout the the  other  Remembering  Appendix  E) .  was  11 weeks of the  hand,  was  that  the  The  for  of  consistently experiment.  consistently pK  pH  oxalic  less  acid  than  2  C i t r i c acid,  on  greater acid  oxalic  than is  pH  1.23,  2.0. at  pH  s l i g h t l y l e s s than 2 approximately 80% of the a c i d i s i n the d i s s o c i a t e d form HL".  The  pK,  f o r c i t r i c a c i d i s 3.14  and  at  50  pH  slightly  in  t h e u n d i s s o c i a t e d form  base  higher  such  with  electrons Weathering  citric  acid  to  the action  H  available  ions  Furrer  and  acid  of the mineral,  solely  by  could  conducted acids  a  values."  investigated Thus,  In  affinity  case  a metal  +  granodiorite into solution experiment.  levels reveal  the  supports  was  a t lower pH  range  prevailed.  a high  from  higher  below  decrease  stability  has a greater  f o rthe organic  part  i n t h e batch experiment This result  over  the ligand  extracted  f o r t h e most  and t h e i r  i o n , and t h e metal  f o r OH" t h a n Fe  this  have  the  In the case of  s u r f a c e complex  f o rthe metal  of  acid  of  decreased  LIGAND  oxalate,  t o form because  a greater affinity  study  surface ligands  o r g a n i c c o m p l e x may  f o rH t h a n  Finally  R  "most l i k e l y  of  the deprotonated  constant but unlikely  have  the rate  of protonated  the  citric  (pH 2 . 5 - 6 . 0 ) ,  but not oxalate,  pH  solution,  pH.  citrate,  by t h e presence  i n the  due t o t h e g r e a t e r number o f  (1983)  The authors concluded,  acid  outcompete  a t a lower  dilute  whereas  acidolysis  support t h e e x p l a n a t i o n g i v e n above.  caused  available for  so, the o x a l i c  of acidolysis i n solution  Lewis  from t h e u n d i s s o c i a t e d c i t r i c  findings  pH=4.5.  the  Lewis  and even  Stumm  from  are then  proceed  of S-AI2O3in  dissolution  The e l e c t r o n s acid  complexation,  through +  will  99% o f t h e a c i d i s  oxalic  a metal  solution,  addition  H3L.  are available  acid.  in  2, a p p r o x i m a t e l y  of the dissociated  complexation no  than  i o n may ligand.  basalt  levels  and  brought  compared w i t h t h e column  the findings  o f S i e v e r and  51  Woodford  (1979) who  minerals  i n buffered  excluded.  In  experiment,  the  observed t h a t solutions  the  was  d i s s o l u t i o n of  more r a p i d when a i r  more o x i d i z i n g environment of  dissolution  in  the  mafic  presence  slowed by the armoring e f f e c t of a Fe  (0H)  of  the  oxygen  was  column may  be  precipitate.  3  Also  the c o n t r i b u t i o n of p h y s i c a l weathering as a r e s u l t of shaking cannot be  2 .  overlooked.  C a l c i u m Mass  balance  calculations  spectrophotometry Appendix B and other  acids  in  granodiorite. material  stability  t o the  extracting  comparable  of  the  ability Ca,  from  acids.  Ca,  depicted  of c i t r i c both  AA in  acid  over  basalt  and  Also  the  differences  in  c o n s t a n t s cannot be used i n the case o f c i t r i c as the  strength  f o r both  (See  yellow  of the  Ca-ligand  Table 2) .  answer p r e s e n t s i t s e l f the  dissolved  and  In t h i s case t h e r e f o r e the i n f l u e n c e of parent  power  oxalic acids  of  point  for  N)  i s overshadowed by other f a c t o r s which determine the  extracting  the  C,  analyses  (Appendix  i n the  p r e c i p i t a t e which  complexes  I t i s more l i k e l y  XRD  analyses  formed  i n the  and are that  (Appendix oxalic  K)  acid  l e a c h i n g treatments of b a s a l t and g r a n o d i o r i t e .  The D-spacing  peaks  and  of  confirming salt  Ca-oxalate  appear  at  3.19,  2.37  1.89  the presence of t h i s s a l t i n the p r e c i p i t a t e .  i s highly  insoluble  and  although o x a l i c a c i d may  A  0  This have  e f f e c t i v e l y competed w i t h c i t r i c a c i d i n detaching Ca from the  52  m i n e r a l much l e s s would remain i n s o l u b l e form.  The formation  o f a Ca-oxalate p r e c i p i t a t e might a l s o e x p l a i n why t h e a c e t i c a c i d s o l u t i o n showed s i g n i f i c a n t l y h i g h e r l e v e l s o f d i s s o l v e d Ca  f o r b a s a l t i c column  constant that  even  ligand  was no s i g n i f i c a n t d i f f e r e n c e  i n s o l u b i l i z e d Ca from  i n t h e batch experiment.  s o l u b i l i t y o f A l i n e q u i l i b r i u m w i t h aluminum oxide  hydroxide  minerals  i s highly  1000-fold f o r each u n i t . is  A t t h e 95% l e v e l  Aluminum The  and  t h e most s o l u b l e  soils; A1(0H)  rather  (See F i g u r e  Figure species  than  of A l  4 ) . Amorphous A1(0H)  3  i s c o n t r o l l e d by amorphous  3 +  gibbsite  the  5 shows the a c t i v i t y  i n equilibrium  activity  with  of A l  o f water  3 +  Al  3 +  is  and i t s h y d r o l y s i s  gibbsite.  forming  of  1979).  The  predominant below pH 4.7 and i s o c t a h e d r a l l y molecules  decreasing  form o f aluminum hydroxide expected i n  when the a c t i v i t y 3  pH dependent,  approximately 42 times h i g h e r (Lindsay,  six  the s t a b i l i t y  l i g a n d was l e s s than  (pK = 3 . 4 ) .  o x a l i c and a c e t i c a c i d leachates  3 .  though  (pK = 1.24) f o r the C a - a c e t i c  f o r the Ca-oxalic  there  samples  A1(H 0) 2  6  predominant between pH 4.7 and pH 6.5, A1(0H)  Al  3 +  ion i s  co-ordinated . 3  to  A1(0H) + i s 2  between pH 6.5  *  and  8, and A1(0H)  4  above pH 8.  A c t i v i t y of A l alone  however.  i n s o l u t i o n i s not p r e d i c t a b l e  3 +  For example,  t h e presence  from pH  of s i l i c a  at  a c t i v i t i e s above 10" decreases the e q u i l i b r i u m o f d i s s o l v e d 4  2  F i g u r e 4:  3  4  5  6 PH  7  8  9  The a c t i v i t y o f A l and i t s hydrolysis species i n e q u i l i b r i u m with g i b b s i t e . 3  +  F i g u r e 5:  The s o l u b i l i t y o f v a r i o u s aluminum o x i d e s and h y d r i d e s . Source: Lindsay,  Source: Lindsay,  1979  1979  54  Al  activities  of  Al  in  3 +  therefore as  a  at  of  (Drever,  with  less than that  categorized  f o r aluminum o x i d e s  Al-silicate  by g e o l o g i s t s  of  reference  bonding.  a s one  its relative  have  activity  in  and  water  has  least soluble  i t has  compared  loss  in  been  elements  weathering.  been  which the  is  hydroxides,  minerals during  against  been  The  Aluminum  of the  immobility  "fixed-element"  elements  1982).  aluminosilicates  f r o m a l u m i n o u s r o c k s and  Because  other  values  equilibrium  result  released  a l l pH  used and  as  a  gain  studies  of  of  rock  alteration. The  graphs  solution  (See  experiments basalt H0  and  show  natural  by  the  95%  fairly  of  at  pH  4  M/liter.  3  34  percentage  a  M.  Mass  A1 0 2  parent material  3  water  of  the  except of  Al  acid  and  column from  HC1  and in  dissolved Al  in  acid  HC1  in  3 +  effective  brought  3 +  and  acid,  least  in very  Al  aluminum  acetic  findings that  on  or  alkaline  into  solution  basalt  and  at  the  r a n g e d f r o m a p p r o x i m a t e l y 3.7  to  7.4  balance  or  4 - 9 6  M  and  calculations  from less  between the  io"  gibbsite at  1%  batch  release  was  of  significant difference  extracted was  both  r e s u l t of  These l e v e l s f a l l  equilibrium with 10" "  as  s h o w e d no and  for  linear  acetic 4  concentration  C)  concentration  confidence level  10  and  systems i s low  action  the  supports the  The  granodiorite  B  Distilled and  3 +  water  conditions.  at  a  granodiorite  dissolving Al  in  Appendix  extraction.  2  x  illustrating  basaltic  for these  activity amorphous showed  and 3  of  Al  3 +  Al(OH)  that  3  the  granodioritic  extractions.  55  The greatly  efficacy  of  Al  extraction  i n c r e a s e d when o r g a n i c c h e l a t i n g  weathering agents.  from column and  and  7.6%  column  and  Again the d i f f e r e n c e s  be p a r t l y a t t r i b u t e d t o d i f f e r e n c e s acids.  The  than c i t r i c  oxalic acid solution 2.2).  as  calculations,  and  Oxalic 15.8%  batch  acid  of  the  experiments  i n d i s s o l u t i o n power  may  i n s o l u t i o n pH of the (pH<2.0) was  slightly  two less was  8 0% d i s s o c i a t e d a t t h a t pH forming HL" whereas c i t r i c a c i d  was  99%  (pH  acted  As noted e a r l i e r o x a l i c a c i d  still  acid  was  of the g r a n o d i o r i t i c AlgC"3  e x t r a c t e d 13.2%  from  A I 2 O 3  respectively.  solutions  batch experiments r e s p e c t i v e l y .  even more e f f e c t i v e and  granodioritic  granodiorite  A c c o r d i n g to mass balance  c i t r i c a c i d e x t r a c t e d 4-9%  was  from  i n u n d i s s o c i a t e d form.  f a c t o r s t h e r e f o r e favored o x a l i c In  addition  the  must be c o n s i d e r e d .  Both a c i d i c and  chelating  acid.  mineralogical  make-up of  granodiorite  As noted, Boyle et a l . (1974) have shown  e x p e r i m e n t a l l y the d r a s t i c e f f e c t of o x a l i c a c i d treatment micas and micaceous c l a y s .  The sheet s t r u c t u r e was  d e s t r o y e d as the c o n s t i t u e n t s a t pH  3,  the  destruction  completely  became s o l u b l e or amorphous and  of b i o t i t e was  almost t o t a l .  The  g r e a t e r a t t a c k of b i o t i t e by o x a l i c a c i d r e l a t i v e t o t h a t citric This  a c i d was could  confirmed i n XRD  therefore  is  extraction  interesting from  batch  analyses  contribute  s o l u b i l i z e d A l i n the o x a l i c a c i d It  to  on  to  (See  higher  by  Appendix  K).  levels  of  leachate.  note  granodiorite  that  the  show a  graphs constant  for  Al  linear  56  r e l a t i o n s h i p o f i o n e x t r a c t e d v e r s u s time.  T h i s suggests t h a t  p h y s i c a l weathering from shaking not o n l y broke down a c a t i o n depleted  layer  weathering.  but  Also,  opened  up  concentrations  new  surfaces  of A l  3 +  to  further  dissolved  i n both  o x a l i c and c i t r i c a c i d s o l u t i o n s were i n approximately a  1:1  r a t i o w i t h t h a t o f S i e x t r a c t e d by the same a c i d s i n the batch experiment. A l : S i r a t i o s were <1 oxalic  A l and  i n the column experiment  S i curves showed d e c l i n i n g r a t e s .  l e v e l s of A l e x t r a c t e d were lower than t h a t  and Also  f o r batch.  both the All  three observations  suggest t h a t an a l t e r e d s u r f a c e was not as  easily  that  detached,  remained  in localized  precipitates  may  microenvironments,  have  formed  or that  and  preferred  c h a n n e l l i n g through the column c o u l d have c o n t r i b u t e d t o lower and  d e c l i n i n g rates  of d i s s o l u t i o n , as w e l l  as incongruent  weathering. The e f f i c a c y of A l e x t r a c t i o n from b a s a l t by c i t r i c o x a l i c a c i d exceeded  t h a t of the n o n - c h e l a t i n g  acids  and  i n the  f i r s t week o f the experiment but q u i c k l y dropped o f f . In f a c t the graph  (Appendix C) showing d i s s o l u t i o n o f A l from b a s a l t  i n the batch experiment r e v e a l s t h a t a c e t i c a c i d and HC1 were more s u c c e s s f u l  i n d i s s o l v i n g A l throughout  Examination o f batch s o l u t i o n pH's to  the g r e a t e r  acidity  several  weeks.  (Appendix E) q u i c k l y p o i n t  of a c e t i c a c i d and  HC1  (pH<3.5) i n  c o n t r a s t t o c i t r i c a c i d (pH=4.0) and o x a l i c a c i d (pH 4.5-5.0). Differences  i n pH however, do not d i r e c t l y  e x p l a i n why  the  57  more a l k a l i n e o x a l i c a c i d s o l u t i o n e x t r a c t e d h i g h e r l e v e l s o f A l than d i d the c i t r i c a c i d s o l u t i o n .  A t the r e s p e c t i v e pH's,  the  2  chelating  1  e f f e c t o f the o x a l i c L " anion c o u l d  have outcompeted the H L- anion o f c i t r i c  acid.  2  Finally  i t i s important  possibly  to highlight  the f a c t  that  s o l u b l e A l l e v e l s f o r a l l treatments were f a r l e s s i n b a s a l t experiments than  f o r granodiorite  s p i t e o f t h e f a c t t h a t the % A1 0 2  XRF  was  15.17%,  granodiorite. solutions  only  was  much  higher  of A l released  amount  pH o f s o l u t i o n s . mixed m i n e r a l s .  silicate  in  than  16.61%  in  weathering  basalt  than  out by Manley and Evans (198 6), t h e  a c i d s was s i g n i f i c a n t l y  up  is  as determined by  less  after  total  bound  This  Again i t i s t o be noted t h a t pH o f e x t r a c t i n g  As pointed  not  i n basalt  3  slightly  granodiorite.  organic  experiments.  from  feldspars  correlated  by d i f f e r e n t  (r=.95) w i t h t h e  Such could be the case i n the weathering o f Secondly, very high l e v e l s of S i which were  i n quartz  were  anion as explained  released  from  e a r l i e r could  basalt.  The  have p r e c i p i t a t e d  any r e l e a s e d A l c a t i o n s thereby suppressing l e v e l s o f s o l u b l e Al.  Also  a t pH < 5 hydroxyaluminum s p e c i e s  orthosilicic  a c i d to give  imogolite) .  Thirdly,  granodiorite  originated  intensities  stable much from  may r e a c t  sols or solutions  of  the  Al  biotite.  f o r b i o t i t e showed the g r e a t e s t  m i n e r a l subsequent t o weathering by c i t r i c  with  (proto-  released  from  The  peak  XRD  decrease o f any  and o x a l i c a c i d s .  B i o t i t e was t h e r e f o r e l e s s r e s i s t a n t t o a c i d a t t a c k than were  58  any of the A l - b e a r i n g m i n e r a l s comprising the b a s a l t i c parent material.  4.  Silicon The  s o l u b i l i t y of s i l i c a  expected  to  range  (quartz) and corresponds  from  10"  i s determined  2-74  minerals i n terms of H S i 0 4  M  (amorphous  for equilibrium  t o a range of 6 t o 60 ppm.  intermediate s o l u b i l i t i e s including Si0 estimated levels  to  of  have  silica  a  solubility  brought  into  with  ppm.  The  respect to  s i l i c a brought  to  4  i n water.  i n water of  This  solution  by  10' ' M.  The  dissolution  of  3  and H 0 2  10  were w e l l  s o l u t i o n s were t h e r e f o r e u n d e r s a t u r a t e d  amorphous s i l i c a .  However, the  levels  i n t o s o l u t i o n as a r e s u l t of o x a l i c and  a c i d r e l e a s e d approximately  2 00 x the amount s i l i c a  e q u i l i b r i u m w i t h amorphous s i l i c a .  a l i t t l e more than 100 x w i t h amorphous s i l i c a analyses  by  of  citric  (See Appendix  For example, b a s a l t leached i n the batch experiment  No  10" M  ( s o i l ) which has been  2  a c i d d i s s o l u t i o n were e x c e e d i n g l y h i g h .  in  is  Other m i n e r a l s have  b a s a l t and g r a n o d i o r i t e by a c e t i c a c i d , HC1 below 60  silica)  4  N).  citric  i n water  Oxalic acid released  the amount of s i l i c a  i n equilibrium  i n water.  were  carried  out  to  d i s c r i m i n a t e what  percentage of t h i s s i l i c a was i n e i t h e r complexed or c o l l o i d a l form. to  I t i s quite l i k e l y that c o l l o i d a l p a r t i c l e s contributed  the  proposed  very  high  readings.  extracting  soils  with  Elgawhary 0.02  M  and Ca  Lindsay  (1972)  i n order t o  keep  59  colloidal  silica  filtration  flocculated  corresponded  expected  from  and  more  solubility  nearly  have been  carried  in  fact  much  of  out,  the  levels  In the  filtration  s e g r e g a t i n g d i f f e r e n t forms of s i l i c a If  the  predictions.  column experiments,  should  to  as  a  in soil of  case  o f the  as  When t h i s  used, they found t h a t measured s i l i c a  solution  sample  as w e l l  o f samples i n which s i l i c a i s measured.  procedure was  batch  during extraction,  H Si0 4  of  4  the  extraction  first  step i n  in solution.  silica  detected  by  AA  spectrophotometry was c o l l o i d a l i t may be surmised t h a t these particles  to  the  e x t r a c t i o n of more e a s i l y d i s s o l v e d ions such as Fe, Mg,  Na,  Ca  or  were  K.  brought  This  into  unstable  solution  cation  subsequent  depleted  altered  zone,  a c c o r d i n g t o Berner and Schott (1982), c o u l d then break down as  dissolution  proceeds  releasing  T h i s phenomenon would e x p l a i n why was al.  the h i g h e s t . (1982) ,  forsterite groups to  the and  the  silicate  framework.  s i l i c a r e l e a s e d form b a s a l t  In the weathering experiments o f Smith e t ferromagnesium  olivine,  having  m i n e r a l s such  as  Mg  the  and  Fe  separating Si-O-tetrahedra, offered  as  least  fayalite, metaloxy  resistance  a c i d a t t a c k and r e l e a s e d s u b s t a n t i a l amounts o f monomeric  silica. samples  In c o n t r a s t , much of the s i l i c a was  bound  i n the quartz  i n the g r a n o d i o r i t e  fraction,  a  tectosilicate  h i g h l y r e s i s t a n t t o weathering. Again,  the p o s s i b i l i t y  of p r o t o - i m o q o l i t e e x i s t i n g  in  s o l u t i o n a l s o cannot be overlooked as t h i s s p e c i e s i s s o l u b l e  60  a t pH  <5. As d i s c u s s e d  earlier,  i n v e s t i g a t i o n s t o determine i o n i c  s p e c i a t i o n i n c h e l a t i n g s o l u t i o n s are s t i l l i n t h e i r So  far,  thermodynamic  stability scarce  composition  and  of o r g a n i c complexes i n aqueous s o l u t i o n are  very  in  the  differentiated  data  describing  literature. 3  different  Henderson forms  of  and  silica  m i n e r a l s by the a c t i o n of an o x a l i c - p r o d u c i n g as  follows:  corresponding silica  infancy.  and  Duff released  from  s t r a i n of  fungi  ammonium-molybidate-reactive to  total  silica,  amorphous s i l i c a .  colloidal  Huang and  (1963)  (AMR)  silica  polymerized  Keller  (CP)  (1971) noted  t h a t d i s s o l v e d S i i n .01 M complexing a c i d s o l u t i o n s exceeded 2-35  times i t s c o n c e n t r a t i o n  however determine the  i n d i s t i l l e d water.  various  forms of  They d i d not  silica  brought  into  solution. Some f i n a l p o i n t s are worth (1)  Although the  citric  and  curves  oxalic acid  noting:  for basaltic s i l i c a  intersected  extraction  a t week 5 i n the  experiment, the t o t a l amounts of s i l i c a e x t r a c t e d were  equal.  indicate that the  Mass  balance  calculations  t o t a l dissolved  b a s a l t i c parent m a t e r i a l  silica in b o t h  (See  column  i n 11 weeks Appendix  accounted f o r 8.52% citric  by  and  N) of  oxalic acid  treatments. (2)  In the batch experiment c i t r i c a c i d e x t r a c t e d  oxalic  acid  granodiorite  7.52%  silica  from  showed a reversed  basalt.  trend.  11.62% and  Dissolution  Oxalic acid  of  extracted  61  2.24 and 2.86% o f the parent m a t e r i a l s i l i c a from column and batch r e s p e c t i v e l y . 0.88%  C i t r i c a c i d on t h e o t h e r hand e x t r a c t e d  and 1.52% o f t h e parent m a t e r i a l s i l i c a from column and  batch  respectively.  differences  This  reverse  i n pH o f t h e s o l u t i o n s ,  trend  may  although  be  due t o  generally, S i  d i s s o l u t i o n i s thought t o be f a r l e s s s e n s i t i v e t o pH changes than t h a t f o r o t h e r i o n s .  In f a c t t h e l o g a c t i v i t y  i n e q u i l i b r i u m w i t h v a r i o u s forms o f S i 0  2  of H Si0 4  4  i s constant i n the  range pH 2 t o pH 9, and only a t pH v a l u e s above 9 does the s o l u b i l i t y o f s i l i c a i n c r e a s e s h a r p l y because o f t h e formation of  silicate  several soils  ions  (Elgawhary  and Lindsay  1972).  However,  s t u d i e s have r e p o r t e d t h a t t h e r e l e a s e o f H S i 0 4  and many  silicate  minerals  greatly  increased  4  by  as pH  changed from 7.0 t o 4.0 (McKeague and C l i n e , 1963; Beckworth and Reeve, 1964; Huang and Jackson,  1968 and Weaver e t a l . ,  1968).  5.  Sodium and Potassium Hydrated metal c a t i o n s such as Na+ and K+ a r e extremely  weak a c i d s their  (pKa=15) which f a i l  enveloping  sheath  to dissociate  o f water molecules  h i g h pH v a l u e s a r e reached.  a proton  until  from  extremely  Because t h e water molecules o f  the h y d r a t i o n sheath a r e doubly p r o t o n a t e d a t normal s o i l pH v a l u e , t h e r e i s l i t t l e tendency f o r these a l k a l i metal c a t i o n s t o c o - o r d i n a t e with e l e c t r o p h i l i c c e n t e r s on m i n e r a l s u r f a c e s . T h e r e f o r e they a c t as i n d i f f e r e n t ions and over t h e pH range  62  commonly met  i n s o i l s , the predominant h y d r a t i o n s t a t e of the  i o n s i s constant. as the Na+  a)  Thus sodium and potassium are p r e s e n t  and K+  ions i n s o l u t i o n .  Sodium It  i s apparent  from the  mass balance c a l c u l a t i o n s  the graphs of sodium i n s o l u t i o n v s . time C)  t h a t the  two  than  were  confidence  acetic  acid,  of  weathering  agreement with reported  HC1  l e v e l there was  concentrations  solutions  (Appendices B  c h e l a t i n g a c i d s were a t b e s t  more e f f e c t i v e i n e x t r a c t i n g Na  the  only  the  from b a s a l t and  or  H 0.  In  2  solubilized basaltic  f i n d i n g of  Na  in  parent  slightly  granodiorite  fact  at  the  5  rock.  Huang and  and m i c r o c l i n e i n organic a c i d s was deionized  and  the  95%  no s i g n i f i c a n t d i f f e r e n c e between  t h a t the d i s s o l u t i o n of a l k a l i  of magnitude as  only  and  extracting This  Keller  is  (1970)  in who  i o n s from muscovite  found t o be the same order  water or  C0 -charged water.  The  2  authors concluded t h a t " i t i s u n l i k e l y t h a t monovalent c a t i o n chelates  are  formed  during  organic  acid  dissolution  of  minerals". The  s o l u t i o n curves a l s o p o i n t t o a r a p i d e a r l y r e l e a s e  o f sodium f o l l o w e d by d e c l i n i n g r a t e s approaching steady s t a t e towards Week 11  of the  experiment.  This  i s a t t r i b u t e d to  e i t h e r d i s s o l u t i o n of h y p e r f i n e s or t o the r a p i d exchange of H  +  ions  extracted  for  the  were  Na+ the  ion  (hydrolysis).  highest  for  citric  The and  levels oxalic  of  Na  acid  -  63  granodiorite and  dissolution.  A t the 95% c o n f i d e n c e l e v e l  citric  oxalic acid dissolved  s i g n i f i c a n t l y h i g h e r l e v e l s o f Na  than d i d t h e o t h e r a c i d s .  T h i s may be due t o t h e f a c t t h a t  citric  and o x a l i c a c i d were the most e f f e c t i v e i n a t t a c k i n g  hornblende, pyroxene and p l a g i o c l a s e , which s e r v e d as sources o f the Na i o n .  b)  Potassium Mass  extracted Na.  balance  calculations  and  of a l l , n o n - c h e l a t i n g a c i d s  e x t r a c t i n g K as the c h e l a t i n g a c i d s . release  declining  rates  of K i n t h e f i r s t of r e l e a s e  Rates then g e n t l y until  graphs  of  K  from basalt show s i m i l a r t r e n d s t o those noted f o r  First  a rapid  solution  until  increased  approached  0  Secondly, t h e r e o c c u r r e d week f o l l o w e d  by  sharply  Week 3 of the experiment.  f o r 1 t o 2 weeks, then decreased  t h e end of week 11.  treatments  a r e as e f f e c t i v e i n  The curves at  the  end  for a l l extraction of  s u g g e s t i n g t h a t the number o f a c t i v e s u r f a c e or muscovite were d e c l i n i n g .  the  experiment  s i t e s of b i o t i t e  Mass balance c a l c u l a t i o n s show  t h a t only a v e r y small percentage (<2%) of t h e K was removed from the b a s a l t i c parent m a t e r i a l through l e a c h i n g .  Evidently  what remained, l i k e l y i n the muscovite, was not a c c e s s i b l e t o f u r t h e r i o n i c exchange with H . +  Mass extracted successful  balance from  calculations  granodiorite  i n extracting  and  show  solution that  as much as 40%  graphs  oxalic (column)  acid  of  K  was  and 50%  64  (batch) of the  K contained  i n the  parent m a t e r i a l .  In  the  batch experiment t h i s amounted t o approximately 5 times t h a t of a c e t i c a c i d , 12 H 0.  Citric  2  acid extracted  the K contained other  three  chelating  times t h a t of HCl, 13%  and  29  (column) and  times t h a t 22%  (batch)  of of  i n the parent m a t e r i a l , a l s o w e l l ahead of the  extracting  acids  were  acids.  indeed  Does  able  to  a n a l y s i s of weathered c r u s t m a t e r i a l  this  mean  complex  that  the  The  XRD  K?  (Appendix K )  suggests  2  the p o s s i b i l i t y of a K-oxalate per hydrate s a l t h a v i n g formed; however, a more l i k e l y c l u e i s g i v e n i n the X-Ray d i f f r a c t i o n analyses  (Appendix  I)  which  shows  a  dramatic  drop  i n t e n s i t y f o r the b i o t i t e peak weathered by o x a l i c and acid. in  As  noted e a r l i e r ,  dissolving biotite  octahedral  layer.  associated  with  interlayer  K,  and  in  citric  o x a l i c a c i d i s extremely e f f e c t i v e  through  attack  of  Subsequent o x i d a t i o n ejection  of  octahedral  a contraction  b i o t i t e sheet ( G i l k e s , R.J.  of  the  Mg  and  Fe  in  of o c t a h e d r a l  the  Fe i s  cations,  loss  of  b-dimension  of  the  1979).  The  and Suddhiprakarn, A.  K detected i n AA s o l u t i o n analyses c o u l d have been s o l u b i l i z e d indirectly  f o l l o w i n g the  chelating acid.  i n i t i a l a t t a c k of Mg  and  Fe by  the  65  Mineral  Ion Calcium  -  Hornblende, Pyroxene, Plagioclase  Magnesium  -  O l i v i n e , B i o t i t e , Hornblende, Pyroxene  Sodium  -  Hornblende, Plagioclase { a l b i t e ) , Pyroxene  Potassium  -  B i o t i t e , Muscovite, K-Feldspar  Iron  -  Pyroxene (Pigeonite, Augite, Hypersthene) - Fe(II) Hornblende - Fe(III):Fe(II) r a t i o often high B i o t i t e - Fe(III):Fe(II) r a t i o approximately equal O l i v i n e - Fe(II) Magnetite - F e ( I I I ) , F e ( I I ) ; Ilmenite - F e ( I I ) , Hematite - Fe(II)  Aluminium  - Feldspars, Pyroxene, Hornblende, Micas  Silicon  - Feldspars, Pyroxene, Hornblende, Quartz, Micas, Olivine  TABLE 3:  SOURCE OF IONS FROM BASALTIC AND GRANODIORITIC PARENT MATERIAL  66  Group  Name  Composition  K-Feldspar Tectosilicate (orthoclase, Microcline)  K Al S i 0  Plagioclase Tectosilicate (oligoclase, Labradorite,r anorthite)  (Na, Ca) A l S i 3,80  Plagioclase (Albite)  Tectosilicate  Na A l S i 0  Pyroxene (Pigeonite) (Hypersthene) (Enstatite) (Augite)  Inosilicate Single chain  3  8  U  3  8  (Ca, Mg, F e ) S i 0 Mg S i 0 (Ca,Na)(Mg,Fe,Al,Ti) (SiAl) 0 3  2  2  6  2  Hornbelende (amphibole)  Inosilicate  6  ( M' g , F2e? *", F e3+, A l ) (Al, S i ) 0 (0H) ( C a  N a  3  2  3+  5  8  Double chain Olivine (Fayalite) (Forsterite)  Nesosilicate  Biotite  Phyllosilicate  2 2  2  (Mg,Fe) S i 0 4 (Fe Si 0 ) 4[(Mg,Fe) S i 0 ] 2  4  2  4  2  4  K(Mg,Fe ) (Al,Fe )Si 0 (OH,F) 2+  3  3 +  3  1 0  2  Muscovite  Phyllosilicate  K,A1 (A1 S i ) 0  Quartz  Tectosilicate  X-Si0  Ilmenite  Iron Titanate  FeOTiO,  Hematite  Iron Oxide  Magnetite  Iron Oxide  Fe 0  Anatase  Titanium Oxide  B-TiO-  Periclase  Magnesium Oxide  MgO  TABLE 4 :  2  F e  3  1 Q  (OH)2  2  2°3 2  4  COMPOSITION OF MINERALS IDENTIFIED IN GRANODIORITE fi BASALT BY XRD ANALYSES.  67  A.  Granodiorite C i t r i c Acid 0 (+) (-)  K-Feldspar Plagioclase Hornblende Pyroxene Micas Periclase Ilmenite Magnetite Hematite Quartz B.  ** ** ** ** **  Oxalic Acid 0 (+) (-)  A c e t i c & HC1 HOH 0 ( + ) (-) 0  ** ** *** *** *** ** ** *** **  ('+)  (-)  *  * *  **  ** *  *  Basalt  Plagioclase Hornblende Pyroxene Fayalite Forsterite Micas Magnetite Hematite Quartz  *** *** *** *** *  ** *** **  **  * * **  Note: (0) = No c h a n g e (+) = i n c r e a s e (-) ** = l a r g e c h a n g e *** = v e r y l a r g e c h a n g e .  TABLE 5 :  decrease  * = small  change  CHANGES IN XRD PEAK INTENSITIES IN BASALTIC & GRANODIORITIC MINERALS FOLLOWING 1 1 WEEX BATCH DISSOLUTION EXPERIMENT.  68  R E S U L T S  B .  D i s s o l u t i o n  & D I S C U S S I O N ;  o f  S E C T I O N  I I  B a s a l ta n d G r a n o d i o r i t e  b y  5  L e a c h i n  T r e a t m e n t s  1.  T h e I n f l u e n c e o f B a s a l t The  in  a n d  t h e D i s s o l u t i o n o f  G r a n o d i o r i t e  d i s t r i b u t i o n f o r the concentration  s o l u t i o n v s . time  several  K i n e t i c F a c t o r so n  interesting  shown  i n Appendices  features  regarding  of i o n i c  species  B and C the  reveal  kinetics  d i s s o l u t i o n i n both batch and column experiments.  of  The s l o p e s  of each curve i n d i c a t e immediately whether o r not t h e r a t e o f dissolution  is  increasing,  approaching steady s t a t e . apparent.  Firstly,  declining  or  linear,  ie.  On t h e whole, two t e n d e n c i e s are  t h e curves  for citric  and o x a l i c a c i d  e x t r a c t i o n s f o r Fe, Mg and K, a r e c h a r a c t e r i z e d by an i n i t i a l i n c r e a s e i n r a t e , f o l l o w e d by d e c l i n i n g r a t e s which approached l i n e a r i t y towards the 11th week.  In a l l other i n s t a n c e s , the  curves f o r c i t r i c and o x a l i c a c i d d e c l i n e d from t h e s t a r t and subsequently l e v e l l e d out. the  two  complexing  T h i s i s t o say t h a t the curves f o r  agents  suggest  p a r a b o l i c d i s s o l u t i o n followed  rapid,  perhaps  by s t e a d y - s t a t e  even  dissolution.  Secondly, the curves f o r a c e t i c , HC1 and H 0 e x t r a c t i o n s are 2  l i n e a r and approximately constant, and  K+ curves,  explanation  w i t h the e x c e p t i o n  i n both b a s a l t and g r a n o d i o r i t e .  f o r the constant  o f Na+  A possible  l i n e a r r a t e s over the p e r i o d o f  69  11 weeks may  be found i n c o n s i d e r i n g the r e l a t i v e e x t r a c t i o n  powers of the d i f f e r e n t a c i d s . absorption  data  as  well  as  I t i s obvious from the atomic  mass b a l a n c e  s t a t i s t i c a l a n a l y s i s t h a t a c e t i c a c i d , HC1  calculations and  H0  and  weathered  2  both b a s a l t and g r a n o d i o r i t e t o a much l e s s e r e x t e n t than d i d the c h e l a t i n g a c i d s . ions  brought  Consequently, maximal c o n c e n t r a t i o n s  i n t o s o l u t i o n were  where p r e c i p i t a t e s might form. e q u i l i b r i u m and  f a r from The  as such r e p r e s e n t  reaching  reactions  are  a  of  level  f a r from  an open system where r a t e s  of d i s s o l u t i o n of elements from m i n e r a l s have been determined t o be l i n e a r  (Kodama e t a l . 1983).  In c o n t r a s t , the r a t e of  r e l e a s e of c o n s t i t u e n t elements i n a c l o s e d system decreases e x p o n e n t i a l l y with time (Kodama e t a l . 1983). S e v e r a l f a c t o r s c o u l d c o n t r i b u t e t o the d e c l i n i n g r a t e s of ions brought i n t o s o l u t i o n by c i t r i c and First  of a l l ,  a cation depleted  developed a c c o r d i n g and von Engelhardt built  up,  the  oxalic acid.  surface  l a y e r may  to the theory mentioned e a r l i e r 1938).  rate  of  (Correns  A c c o r d i n g l y , as t h i s a l t e r e d l a y e r  d i s s o l u t i o n decreased.  Eventually,  however, the d e p l e t e d s u r f a c e l a y e r broke down, b e i n g chemically, destroyed was  unstable  u n t i l i t reached an e q u i l i b r i u m t h i c k n e s s ,  being  a t the l a y e r - s o l u t i o n i n t e r f a c e a t the same r a t e i t  formed  weathered  have  at  the  surfaces  layer-mineral revealed  surface.  depletion  earth cations r e l a t i v e to S i .  See  of  Figures  EDX  analysis  alkali 16 and  and 17.  of  alkali Also  a n a l y s i s of the s o l u t i o n s , i n d i c a t i n g h i g h l e v e l s o f c a t i o n i c  70  extraction,  suggest  developed.  The  that  such  a  leached  layer  possibly  h i g h l e v e l s of S i and A l both c o l l o i d a l  and  s o l u b l e , d e t e c t e d through AA spectrophotometry a n a l y s i s o f the s o l u t i o n s , are c o n s i s t e n t w i t h the concept t h a t detachment of s i l i c a t e and  aluminate u n i t s from the c r y s t a l l i n e  f o l l o w s the exchange of H 1982). for  +  for alkalis  framework  (AAgaard and Helgeson,  I n t e r e s t i n g l y , a comparison of the d i s s o l u t i o n graphs  S i and A l i n batch and column experiments r e v e a l s a f a i r l y  l i n e a r r a t e i n the batch  experiment but d e c l i n i n g r a t e s f o r  the column experiment.  T h i s suggests t h a t indeed a p r o t e c t i v e  as  layer  well  as  altered  experiment. physical  In the  grinding,  had  built  case of the batch through  up  in  the  experiment,  shaking  of  column however,  samples  could  c o n t i n u a l l y a s s i s t i n the breakdown of the c h e m i c a l l y u n s t a b l e surfaces, altered  leading surface  to is  steady-state not  broken  dissolution. down,  as  in  Where the  the  column  experiment, d e c r e a s i n g r a t e s of d i s s o l u t i o n o c c u r r e d . There  i s on  observations  the  other  that i n i t i a l  hand, d i r e c t  evidence  from  weathering of s u p e r f i n e s  SEM  adhering  to the s u r f a c e o f unweathered m i n e r a l g r a i n s c o u l d account f o r both the r a p i d r i s e then f a l l weeks o f weathering. hyperfine  particulate  i n r a t e s d u r i n g the  F i g u r e s 6 and matter, to  first  7 show the e x i s t e n c e  an  artifact  the  outer  of  few of  grinding,  adhering  electrostatically  mineral.  A f t e r 11 weeks of weathering the s u r f a c e s o f m i n e r a l  g r a i n s were c l e a n as shown i n F i g u r e 8.  The  surface  of  the  d i s s o l u t i o n of  Figure  6:  Hyperfines adhering to g r a n i t i c surface. 600 x m a g n i f i c a t i o n  Figure  7:  Hyperfines adhering to b a s a l t i c surface. 600 x m a g n i f i c a t i o n  72  Figure 8:  B a s a l t i c g r a i n leached by o x a l i c a c i d f o r 11 weeks. Note absence of hyperfines and prominent etch-pitting. 600 x m a g n i f i c a t i o n  73  these p a r t i c l e s occurred mineral  due  to greater  more r a p i d l y than t h a t of the surface  area,  exposed edges and  l a r g e abundance of s t r a i n e d or broken bonds. the p a r t i c l e s were destroyed, tapered  o f f to  the  linear  bulk the  With time,  the d i s s o l u t i o n r a t e may  rate  of  destruction  of  as  have  the  bulk  clearly  that  mineral. Holdren  and  Berner  (1979)  demonstrated  adhered f i n e p a r t i c l e s c o u l d , i n f a c t , be r e s p o n s i b l e f o r the p s e u d o - p a r a b o l i c stage of l a b o r a t o r y d i s s o l u t i o n experiments. Freshly  ground  unwashed  albite  exhibited  high  initial  d i s s o l u t i o n r a t e s which d i d not appear i f the f i n e p a r t i c l e s were f i r s t  removed by HF-H S0 . 2  Similarly,  non-linear  4  rates  of  dissolution  a t t r i b u t e d t o the presence of edges, corners, etc.  may  cracks,  be holes  and a t a s m a l l e r s c a l e , p o i n t d e f e c t s , i n boundaries  d i s l o c a t i o n s (Schott & P e t i t , 1987). noted,  " I f heterogeneities  F u r r e r and Stumm (1983),  of s u r f a c e  properties (different  phases, d i f f e r e n t p a r t i c l e s i z e , d i f f e r e n t s u r f a c e exist,  parabolic  Linear  rate  laws  d i s s o l u t i o n rates are  usually  and  are  obtained  typically i f the  energies) observed.  pretreatment  renders the s u r f a c e p r o p e r t i e s s u f f i c i e n t l y homogenous."  2.  Incongruent v s . Congruent D i s s o l u t i o n Congruent d i s s o l u t i o n , or  been  demonstrated  undersaturation  in  a c l o s e approach t o  determinations  of  of simple s i l i c a t e m i n e r a l s  i t , has  solubilities  from  i n d i l u t e aqueous  74  s o l u t i o n s a t low t o moderate temperatures when enough time has passed  for equilibrium  studies are: chrysotile  to  be  reached.  Examples  of  such  k a o l i n i t e 25°C, 2 y e a r s ( P o l z e r and Keirt, 1965) ; 90°C,  2  months  (Hostetler  and  Christ,  1968)  magnesium s i l i c a t e s , 100 h r s . (Luce e t a l . 1971) ; and o l i v i n e , 2 months (Grahdstaff,  1986).  Yet many f i e l d s t u d i e s have shown t h a t s i l i c a t e s weather incongruently  i n nature  (Loughman,  1969).  The  laboratory  d i s s o l u t i o n of f e l d s p a r s by i n o r g a n i c and o r g a n i c a c i d s generally  been  observed  Huang and K e l l e r , 1970 and  alkaline  t o be  incongruent  and Gardner,  e a r t h s are  released  1983).  (Correns, Usually,  i n excess  of  has  1963;  alkalis  silica  and  d i s s o l v e d alumina i s l e a s t abundant. C l e a r l y i n a system whereby the parent m a t e r i a l such as basalt  and  granodiorite  assemblages  of  weathering was trace  the  compared.  comprised  undetermined  of  I t was  of  ions  ions  brought  from  of  mixed  stoichiometry,  expected t o take p l a c e .  origin  stoichiometries  was  I t was  into  mineral to  mineral  incongruent impossible to  solution, solution  so  that  could  be  however p o s s i b l e t o draw some c o n c l u s i o n s  i n d i r e c t l y from the experimental data r e g a r d i n g p r e f e r e n t i a l d i s s o l u t i o n of c e r t a i n elements.  T h i s data supported the f a c t  t h a t incongruent weathering had indeed taken p l a c e , a)  F i r s t of a l l , congruent d i s s o l u t i o n may  be i n d i c a t e d by  constant rates of ion released i n t o s o l u t i o n . part  o f the experiment,  rates of d i s s o l u t i o n  For the most f o r the  seven  75  i o n s measured by spectrophotometry were v a r i a b l e , g e n e r a l l y s l o w i n g down w i t h time.  T h i s behaviour i n p a r t r e f l e c t s the  b u i l d - u p o f r e a c t i o n products product  which changes t h e i o n a c t i v i t y  o f t h e s o l u t i o n w i t h r e s p e c t t o the parent m a t e r i a l .  The f o r m a t i o n o f secondary p r e c i p i t a t e s o f any k i n d w i t h i n the system c o n c e a l s reaction  the actual stoichiometry of the d i s s o l u t i o n  and p r e c l u d e s ,  taking place.  by d e f i n i t i o n ,  congruent weathering  The presence o f both amorphous and c r y s t a l l i n e  secondary p r e c i p i t a t e s was r e v e a l e d by Fe, A l , and S i oxide extraction For  a n a l y s i s , scanning  example,  granodiorite  e l e c t r o n microscopy  Figure  9  grains  weathered  shows  an  electron  by  and EDX.  micrograph  citric  acid.  of The  accompanying EDX graph shows a major peak f o r S i and a very minor peak f o r A l s u g g e s t i n g the development o f an amorphous silica  or  a l u m i n o - s i l i c a surface.  Figure  11  features  a  g r a n o d i o r i t e g r a i n weathered by o x a l i c a c i d showing a rounding and c o a l e s c e n c e b)  of the surface t y p i f y i n g a g e l .  X-ray f l u o r e s c e n c e a n a l y s i s measuring the percentages o f  oxides  i n unweathered and weathered samples may be used t o  determine  chemical  comparison  of  losses  changes  and  i n molar  gains. ratios  subsequent t o l e a c h i n g over time, provides  In of  particular, the  oxides,  a strong t o o l to  assess whether weathering has i n f a c t proceeded i n c o n g r u e n t l y . The  following  i s a summary  h i g h l i g h t i n g key  features  which became apparent i n comparing molar r a t i o s o f unweathered to weathered m i n e r a l f o l l o w i n g eleven weeks o f l e a c h i n g .  See  76  Figure 9:  Granodiorite c r u s t materials leached by c i t r i c a c i d f o r 11 weeks. 800 x m a g n i f i c a t i o n  Citric 5000  acid  countl  I'ltp. 1  200 a t e * ZOO a t e *  Elapsed*  cm. Rang? »  10.230 keV Integral  0  •  Figure 10: EDX of sample shown i n Figure 9 . S i peak.  1 8 . ? 3 0 -» 129315  Note prominent  77  Figure 1 1 : G r a n o d i o r i t e g r a i n weathered by o x a l i c a c i d f o r 1 1 weeks Note coalescing surfaces 250 x magnification  78  tables  in  Appendix  c a l c u l a t e d molar  A.  1.  2.  J  give  numerical  values  for  ratios.  G r a n o d i o r i t e 11 weeks - Column and Batch  Experiments  SiOa/Al^s  ratios  treatments  ( O x a l i c a c i d - g r e a t e s t change)  increased  slightly  for a l l  Si02/R2°3 tios i n c r e a s e d f o r a l l treatments ( O x a l i c ra  acid - greatest  3.  which  change).  AlgOs/FegOs r a t i o s  remained  the  same  except  for  o x a l i c a c i d which showed a v e r y h i g h i n c r e a s e .  4.  Bases/Al20 treatments which  5.  3  r a t i o s decreased v e r y s l i g h t l y except  HC1  and  HgO  column  for a l l  experiment  showed a s l i g h t i n c r e a s e .  Bases/Si0  2  ratios  remained  the  same  except  for  o x a l i c and c i t r i c a c i d which showed s l i g h t decrease.  It Al for  were removed p r e f e r e n t i a l l y t o s i l i c a .  o f a l l t h a t Fe and Secondly,  except  t h e o x a l i c a c i d treatment Fe and A l were removed i n a 1:1  ratio. Al.  may t h e r e f o r e be concluded f i r s t  O x a l i c a c i d e x t r a c t e d Fe t o a much g r e a t e r extent than  The removal  o f t h e sum o f Ca, Mg, K and Na was roughly  79  equal t o that  o f A l o r S i , except f o r o x a l i c and c i t r i c  acid  where removal o f the bases s l i g h t l y exceed A l and S i .  8.  Basalt  1.  - 11 weeks - Column and Batch  Si0 /Al 0 2  2  Experiments  r a t i o s decreased f o r c i t r i c and o x a l i c a c i d  3  and i n c r e a s e d f o r a c e t i c a c i d , HC1, and H 0. 2  2.  Si0 /R 0 2  2  r a t i o s i n c r e a s e d f o r a l l treatments  3  acid - greatest  3.  Al 0 /Fe 0 2  3  2  change).  r a t i o s i n c r e a s e d f o r a l l treatments w i t h  3  a v e r y g r e a t change shown f o r c i t r i c  4.  Bases/Al 0 2  3  ratios  ( C i t r i c acid - greatest  5.,  (Citric  Bases/Si0  ratios  2  treatments except H 0  decreased  acid.  f o r a l l treatments  change).  decreased  slightly  ( C i t r i c acid - greatest  2  for a l l change).  The most apparent f e a t u r e i s t h a t of the e x t r a c t i o n power of c i t r i c in  acid  weathering  granodiorite  i n leaching ratios  S i , Fe, and Mg.  for  weathered  were g r e a t e s t f o r the s t r o n g l y  namely o x a l i c and c i t r i c a c i d . of  both  Huang and K e l l e r  In f a c t , basalt  complexing  shifts and acids  These r e s u l t s support the work  (1970), who  concluded t h a t  incongruent  80  weathering  of s i l i c a t e  minerals  d i s s o l u t i o n by c h e l a t i n g a c i d s . and  bases/Si0  2  i s brought  about  through  The decrease i n b a s e s / A l 0 2  r a t i o s may be explained  3  e i t h e r by t h e g r e a t e r  r e l a t i v e e x t r a c t i o n o f t h e bases o r by the scavenging o f A l and  S i by an Fe-oxide c o a t i n g .  Si0 /R 0 2  2  ratios  3  increased,  However, the Al O /'R 0 2  thus  refuting  z  the  2  3  and  latter  explanation.  c)  Incongruent weathering may a l s o a r i s e due t o the presence  of d i s l o c a t i o n s commonly manifested by etch mineral grains.  p i t s on  S t r a i n energy a s s o c i a t e d ' w i t h  reacted  dislocations  may c a t a l y z e the b r e a k i n g o f bonds by e i t h e r a hydronium i o n or  organic  activated  ligand complex  and a c c e l e r a t e (Aagaard  detachment o f t h e a c t i v a t e d  and  formation o f t h e c r i t i c a l Helgeson  complex may  1982).  Also,  occur a t d i f f e r e n t  rates i n d i f f e r e n t crystallograhic directions. Site-selective reaction layer  attack  and c o n t r a d i c t s  as a m i n e r a l being  implies  the n o t i o n dissolved  a  of a p r o t e c t i v e  etch-pitting  and s i t e  surfaces.  selective  dissolution  were observed i n weathered b a s a l t i c and g r a n o d i o r i t i c under t h e scanning e l e c t r o n microscope. increasing  magnification  are a n i s o t r o p i c with r e s p e c t  grains  F i g u r e s 12 t o 14 show  o f a mica g r a i n  a c i d f o r 11 weeks and d r a m a t i c a l l y  surface  by d i f f u s i o n - c o n t r o l l e d  r e a c t i o n should possess smooth, rounded Extensive  surface-controlled  leached by o x a l i c  i l l u s t r a t e that the grains  t o d i s s o l u t i o n and t h a t  Figure 12: Mica g r a i n leached by o x a l i c a c i d - 11 weeks. 200 x magnification  Figure 13: Mica g r a i n leached by o x a l i c a c i d - 11 weeks Note e x f o l i a t i o n . 1100 x m a g n i f i c a t i o n  Figure  14: M i c a g r a i n l e a c h e d b y o x a l i c 2200 x m a g n i f i c a t i o n  acid  11 weeks  "3T-TfcT^rWT77T9~7ul 396  Vert-  counts  Dlsp-  1  Comp.  3  Preset-  200  sees  Elapsed.  200  sees  Sl  Fe fll  »9 Ti  —~Xt3U\  i-  0.000  Rang-.  10.230  keV  10.110 Integral  Figure  0  •  1 5 : EDX o f s a m p l e s h o w n i n F i g u r e 1 4 . Note K and Fe p e a k s .  -f  25201  83  d i s s o l u t i o n occurs a t much g r e a t e r r a t e s on some s u r f a c e s than others.  The  EDX  magnification  analysis  suggests  i n t e r l a m e l l a e regions release of s i l i c a . pitting for  11  15)  removal  of  K  and  likely  of the p a r t i c l e ,  taken  weeks.  at  and  2200X  Fe a  from  delayed  F i g u r e 16 e x e m p l i f i e s more advance e t c h -  of a g r a n o d i o r i t e g r a i n a l s o leached  incongruent It  the  (Figure  The  accompanying  EDX  by o x a l i c a c i d  a n a l y s i s confirms  removal of bases l e a v i n g a s t r o n g  silica  the peak.  i s p o s s i b l e t h a t f u r t h e r d i s s o l u t i o n c o u l d break down the  remaining a l u m i n o - s i l i c a t e l a t t i c e r e l e a s i n g a l l c o n s t i t u e n t s to  solution.  (1979)  that  congruent  I t has this  been suggested by  stage  of  the  reaction  f o r a p a r t i c u l a r mineral,  precipitates  on  the  surface  Holdren  a c t as  is  providing  and  Berner  most  likely  no  secondary  a scavenging armour f o r  ions i n s o l u t i o n . I t should be f u r t h e r noted t h a t the e t c h - p i t t i n g observed i n the micrographs may of  two  distinct  microperthitic 1983) .  a l s o be due to d i f f e r e n t i a l d i s s o l u t i o n  phases as  commonly  found,  exsolution  features  of  f o r example,  feldspars  in  (Gardner  Gardner (1983) p o s t u l a t e d t h a t congruent d i s s o l u t i o n  of two d i s t i n c t but i n t i m a t e l y intergrown phases a t d i f f e r e n t r a t e s may  appear t o be  incongruent  d i s s o l u t i o n of the  bulk  phase. The of  presence of e t c h p i t s  authigenic  phases  on  grain  i n addition to p r e c i p i t a t i o n surfaces  accounted  for  i n c r e a s e i n s p e c i f i c s u r f a c e of the weathered m i n e r a l s .  the (See  84  Figure 16: G r a n o d i o r i t i c grain leached by o x a l i c a c i d 11 weeks. Note p r e f e r e n t i a l d i s s o l u t i o n f o l l o w i n g c r y s t a l l o g r a p h i c features (honeycomb etching) 1200 x m a g n i f i c a t i o n  l l . - i u r .'JUS  /ert« PfiC  Presvt• Else »cl.  ['t*p>  1'  c  Ml  : n* o.ooe  C» ; Par.g't™  i 0.  23(Tk c V  Integral  0  Figure 17: EDX o f sample shown i n Figure 16.  2tt0 sees I ?1 s e e s  85  Appendix L) . A f t e r 11 weeks, the s u r f a c e area o f g r a n o d i o r i t e i n c r e a s e d 4-5 f o l d and t h a t o f b a s a l t 4-7 f o l d . Speyer  (1986) found i n t h e i r  alkali  feldspars d i s s o l u t i o n that  smaller, could  study o f the s t o i c h i o m e t r y as t h e g r a i n s i z e  t h e r e a c t i o n became more n e a r l y  partly  explain  why  Holdren and  congruent.  d i s s o l u t i o n approached  of  became This  linearity  towards t h e end o f the 11 week experiment. Figures pitting.  18 t o 25 show other  types and stages  of etch-  VO CO  Figure  18: B a s a l t i c g r a i n l e a c h e d by o x a l i c a c i d f o r 11 weeks Note smooth v s a c t i v e l y e r o d i n g s u r f a c e 1200 x m a g n i f i c a t i o n  Figure  19: B a s a l t i c g r a i n l e a c h e d weeks 600 x m a g n i f i c a t i o n  by o x a l i c a c i d f o r 11  Figure  20: G r a n o d i o r i t e g r a i n l e a c h e d i n o x a l i c a c i d f o r 11 weeks Note c o n t r a s t i n r o u g h s u r f a c e f e a t u r e s t o t h a t o f u n d e r l y i n g smooth f e a t u r e s 800 x m a g n i f i c a t i o n  Figure  21: G r a n o d i o r i t i c g r a i n l e a c h e d i n o x a l i c a c i d f o r 11 weeks Note a c t i v e l y e r o d i n g s u r f a c e i n f o r e g r o u n d 1500 x m a g n i f i c a t i o n  Figure 2 2 : B a s a l t i c g r a i n leached i n o x a l i c a c i d f o r H 800 x magnification  K  i  g  u  r  e  2  3  :  B a s a l t i c g r a i n leached i n o x a l i c a c i d f o r 11 m  a  g  n  i  f  i  c  a  t  i  o  n  89  Figure 24: B a s a l t i c g r a i n leached i n o x a l i c a c i d f o r 11 weeks.  Note prominent etch p i t 600 x m a g n i f i c a t i o n  90  Figure 25: Granodiorite g r a i n leached i n o x a l i c a c i d f o r 11 weeks. Note contrast i n a c t i v e l y eroding surface i n centre t o smoother s t r i a t e d surfaces i n foreground 400 x magnification  91  RESULTS AND  DISCUSSION: SECTION I I I  C. Formation o f Organo and Amorphous P r e c i p i t a t i o n Products  The Fe,  r e s u l t s of the a n a l y s e s t o determine the extent of  A l , and  basaltic  Si  oxide  formation  s u r f a c e s i s summarized  on  the  granodioritic A2.  i n Appendix  and  Graphic  d e p i c t i o n of t h i s data i s shown i n Appendix A-|. It both  i s immediately  basalt  remarkably 2.0-2.4%  and  for  a p p r e c i a t i o n of those  found  FepyRO  granodiorite  h i g h . The and  apparent  leached  between  relative  in soils,  extracted  the FepyRO l e v e l s f o r by  oxalic  from  4.7-6.5%.  magnitude  i t i s noted an  Ortho  of  that Humic  As  noted  To  are  between gain  an  levels  to  percentage  of  these  the  Ferric  Vancouver I s l a n d reached a maximum of .50% (G. S i n g l e t o n ,  acid  l e v e l s f o r g r a n o d i o r i t e ranged basalt  the  that  Podzol  on  i n the B h o r i z o n  1978). earlier,  r e s e a r c h (e.g. S c h u p p l i e t  al.1983;  Loveland and Digby,1984) has g i v e n evidence t h a t c o n v e n t i o n a l centrifugation  i s inadequate t o sediment  suspended  material  completely i n pyrophosphate e x t r a c t s a t a pH of 10. Jenroy and Guillet  (1981), found f e r r u g i n o u s p a r t i c l e s >100  nm  diameter  s t i l l p r e s e n t i n Na-pyrophosphate s o l u t i o n s c e n t r i f u g e d a t RCF 40,000, stepwise  whilst  McKeague  centrifugation  and up  Shuppli to  RCF  (1982),  120,000  decreased amounts of Fe and A l i n s o l u t i o n s .  found  that  progressively  C r y s t a l l i n e Form  S o l u b i l i t y ' gms/100 g Cold Water Hot Water  pale yellow, rhomb  0.022  0.026  Fe (C 0 ) .5H 0  Yellow micro c r y s t a l l i n e powder  V.S.  V.S.  Mg oxalate  MgC 0 .2H 0  White powder  .07  0.08  Ca Oxalate  CaC 0  Colorless, cubic  0.00067  0.0014  Ca Oxalate hydrate  CaC 0 H 0  Colorless, cubic  i  1  Al Oxalate  A1 (C 0 ) .4H 0  White powder  i  i  Fe (II) c i t r a t e  FeC H 0 .H 0  White micro phomb  sl. s  —  FeC H 0 .5H 0  Red-brown scales  sl. s  soluble  Mg.citrate, mono-H  MgHC H 0 .5H 0  White granular powder  20  soluble  Ca-citrate  Ca (C H 0 ) 4H 0  White needles  0. 085  0.096  —  —  --  Name  Formulae  Fe (II) Oxalate  FeC 0 .2H 0  Fe (III) Oxalate  2  4  2  2  2  2  4  2  6  4  6  5  3  ?  2  2  7  6  2  5  6  7  5  2  Al-citrate  2  2  2  6  3  4  2  3  4  4  2  (Ill)citrate  2  not given  2  7  2  2 5  Source: Handbook of Chemistry & Physics , 1984.  TABLE  6:  C H E M I C A L D E S C R I P T I O N OF C I T R A T E A N D O X A L A T E S A L T S  93  The  l a b o r a t o r i e s i n the s o i l s c i e n c e department at  are not equipped with a high-speed c e n t r i f u g e  UBC  (6000-8000  RCF  Max.). The Fe measured i n the pyrophosphate e x t r a c t s t h e r e f o r e was ,  not  entirely  strucure  in dissolved  form but  of suspended m a t e r i a l s ,  values.  Mass  balance  present  also  in  the  thereby o v e r e s t i m a t i n g  calculations  the  (Appendix  N) ,  d i f f e r e n t i a t i n g % Fe i n the unweathered sample v . s . Fe i n the dissolved  and  t h a t o f the was  p r e c i p i t a t e d form g i v e  which  exceeded  starting material. Evidently c o l l o i d a l  material  measured i n the AA  thereby i n t r o d u c i n g  values  spectrophotometric s o l u t i o n  analyses  inaccuracy.  I t i s p o s s i b l e t h a t the source of some of t h i s material  originated  from  a  observed  forming  in  both  material  leached,  by  oxalic  yellow  precipitate  granodiorite acid.  and  These  colloidal which  basalt  was  parent  p r e c i p i t a t e s were  examined i n more d e t a i l with the help of a scanning e l e c t r o n microscope  and  chemically  analyzed  by  EDX,  XRD  and  XRF.  A  chemical d e s c r i p t i o n of c i t r a t e and oxalate s a l t s i s g i v e n i n Table 6 t o a s s i s t i n the i d e n t i f i c a t i o n of the p r e c i p i t a t e s . A d i s c u s s i o n of those f i n d i n g s f o l l o w s .  1. G r a n o d i o r i t e O x a l i c P r e c i p i t a t e Magnification distinct  under the  components  of  the  g r a n o d i o r i t e . F i r s t l y , very  e l e c t r o n microscope r e v e a l e d p r e c i p i t a t e which  small  g r a i n s were c l e a r l y v i s i b l e . See  (<5  um)  formed  fragmented  Figure 27. EDX  2  from  mineral  of these  31-Oct-lSiiJB ICslt'J: l b  Vert-  £14 counts  Pisp- 1  PresetE lops?d=  20U iec< 28B t e c s  HI  M" 9  •}-  O.uUU  R.M.ye,  10.338 keV lnt rcir a I  F i g u r e 26: EDX o f sample F i g u r e 27.  shown i n  0  F i g u r e 27: M i n e r a l f r a g m e n t s i n g r a n o d i o r i t i c c r u s t found a f t e r 11 weeks o f l e a c h i n g oxalic acid.  in  F i g u r e 28: EDX of sample shown i n Figure 29.  Figure 29: Amorphous p r e c i p i t a t e i n g r a n o d i o r i t i c crust found a f t e r 11 weeks of leaching i n oxalic acid. 1200 x m a g n i f i c a t i o n  96  grains and  (Figure 26) determined t h e presence o f S i , A l , Ca, Fe  K, i n d i c a t i n g  confirmed  a mafic  m a t e r i a l . XRD o f t h e p r e c i p i t a t e  t h e presence o f hornblende as w e l l as p l a g i o c l a s e .  The second component appeared t o be a s h o r t range ordered " f l u f f y " p r e c i p i t a t e which e x h i b i t e d v e r y h i g h s u r f a c e (Figure 29). The EDX analyses  area.  , ( F i g u r e 28), determined t h e  presence of S i and Fe, i n approximately  50% r a t i o , w i t h l e s s e r  peaks o f A l and Ca. XRD analyses confirmed  t h e presence of Fe-  o x a l a t e hydrate, calcium o x a l a t e and o x a l i c a c i d . I n f a c t , the yellow  colour  i s indicative  of  the  (Handbook of Chemistry and P h y s i c s ,  Fe-oxalate  hydrate  1986).  To date t h e r e i s n e i t h e r any r e p o r t e d evidence  of a S i -  o x a l a t e complex (Drs. Barnes,W. and C l a v e t t e , D . p e r s . comm.), nor  any r e p o r t e d  XRD  peak  data  stability  constants  f o r such. a compound  t o match. I n a d d i t i o n , was  not found  i n the  literature. It  i s l i k e l y t h a t i n an o x a l i c a c i d s o l u t i o n o f pH <2,  protonation  of the g r a n i t i c  surface  (and cleavage  o f the  s i l o x a n o l bond),took p l a c e with subsequent r e l e a s e o f S i ( 0 H ) into  s o l u t i o n . With a S a t u r a t i o n  precipitates  will  form,  Index o f g r e a t e r  and i n f a c t  the f l u f f y  4  than 0,  appearance  shown i n t h e photograqph (Figure 29), i s t y p i c a l o f the metal hydroxide  Si(0H)  4  (Dr. O r v i g , C.E. pers. comm.).  Although no s t a b i l i t y constants a r e t o date g i v e n i n the l i t e r a u r e f o r a S i - o x a l a t e complex i t can be p r e d i c t e d t h a t Fe w i l l e f f e c t i v e l y compete with t h e S i f o r t h e o x a l a t e anion.  97  T h i s c o m p e t i t i o n may p r e c l u d e the chances of S i combining w i t h oxalate. On the o t h e r hand the p o s s i b i l i t y of a S i - o x a l a t e complex cannot  be  ruled  out  of  silicic  interaction  (Dr.  Clavette,D.  acid  and  pers.  silicates  comm.). with  The  organic  components of b i o l o g i c a l systems i s thought t o i n v o l v e s e v e r a l types of chemical bonding such as Si-O-C, Si-N-C, S i - C , a s w e l l as  hydrogen-bonded  only  4-but  also  complexes  5-  and  6-  (Iler,  1979).Furthermore,  co-ordinated  silicon  have  not been  i s o l a t e d and c h a r a c t e r i z e d (Weiss and Herzog, 1978) . Weiss and Herzog  (1978),  [ Si (thpl) or  3  quartz),  tropolone  were a b l e t o p r e c i p i t a t e an o r g a n i c  ] P F b y t r e a t i n g f i n e l y ground s i l i c a  ( s i l i c a gel  6  in  an  aqueous  derivative.  suspension  Tripolones  are  at  pH=  Si-salt,  3.5  abundant  with  in  a  higher  p l a n t s and are s i m i l a r t o o x a l i c a c i d i n  exhibiting bidentate  c h a r a c t e r w i t h a d e l o c a l i z e d Pi-system  i n the a n i o n i c form.  Subsequent  et.  work  in  Sweden  (Sjoberg  al.  1985),  has  i n v e s t i g a t e d complex formation of s i l i c i c a c i d and  silicates  with p o l y o l s (mannitol), s a c c a r i d e s ( g l u c o s e ) , 1,2-  diphenols 29  ( p y r o c a t e c h o l ) , and t r o p o l o n e s . The authors r e p o r t chemical  s h i f t v a l u e s which showed t h a t , a t pH  coordinated s i l i c o n tropolone However,  no  such  complex  aqueous s o l u t i o n s . But  i n neutral  and  promoted. alkaline  i t remains p o s s i b l e t h a t g i v e n  low pH c o n d i t i o n s of the batch and column experiment, a c i d may  NMR  < 3, a hexa-  (SiLjyr-) complex was  occured  Si-  the  oxalic  have formed a complex with s i l i c o n s i m i l a r i n nature  98  t o the s i l i c o n - t r i p o l o n e bond. Finally, pH's  an  Fe-silicate  complex,  known t o  (Dr. C l a v e t t e , D . p e r s . comm.), may  the observed  p r e c i p i t a t e . Although  form  at  low  have c o n t r i b u t e d t o  the EDX  a n a l y s i s g i v e s no  s t r u c t u r a l i n f o r m a t i o n , the h e i g h t of the peaks i n the graph d i d i n d i c a t e t h a t Fe and S i were i n approximately thereby  pointing  existing.  XRD  to  the  peaks  d i a g n o s t i c 2.49  for  or 1.78  possibility Fe2Si0  of  did  4  such  not  A but the presence  1:1 a  appear  ratio,  compound at  of these peaks  the may  have been overshadowed by peaks from o t h e r m i n e r a l s or s a l t s occuring i n higher concentration. The clearly  accumulation shown from  of Fe  the  XRF  i n the data,  "fluffy"  precipitate  (Appendix I ) , whereby  l e v e l s of Fe20 rose as h i g h as 16.22% i n c o n t r a s t t o 5.21% 3  is the in  the unweathered g r a n o d i o r i t e . A l s o the S i O ^ R g O a ^ n d A l ^ ^ / F e ^ s ratios in  (Appendix J) dropped from  the  unweathered  material  5.52  to  and  3.26  5.33 and  respectively 0.90  in  the  p r e c i p i t a t e . I t i s i n t e r e s t i n g t o note t h a t the S i O ^ R ^ s and A  l2°3/ 2°3 r a t i o s Fe  show  just  the  opposite  trend  for  the  weathered g r a n o d i o r i t e g r a i n s which were analyzed s e p a r a t e l y from the  the p r e c i p i t a t e . These r a t i o s were the h i g h e s t f o r a l l recorded  batch and  values  f o r the  column experiments.  5  l e a c h i n g treatments  both  in  T h i s shows a s t r o n g d e p l e t i o n  of Fe from the parent m a t e r i a l . I t may be concluded t h e r e f o r e , t h a t Fe leached from  the g r a n o d i o r i t e i n t o s o l u t i o n i s t o a  l a r g e extent r e a p p e a r i n g i n the p r e c i p i t a t e . For t h i s reason,  •2a-0ct-i9o& a s : a n y * Basalt  Oxalic  2317  Vert.  cn 0>  ' si  ;  counts  :;  Crust blip*  1  -  rtf  ,0.000  200  sees  (.lapsed-  200  sees  10. 110  ->  :  * :'::':::':::i-:::::::::.r« >:::::' I-:::-:::-. ™ ! : ; : . ; . . . . . . . . . i.:....w :  Na  Preset•  °  Range*  Ti  10.230  Fe  Mn  keV Integral  F i g u r e 30: EDX of sample shown i n Figure 31.  0  •  215599  Figure 31: Amorphous p r e c i p i t a t e i n b a s a l t i c c r u s t formed a f t e r 11 weeks of l e a c h i n g i n oxalic acid. 1800 x m a g n i f i c a t i o n  100  mass b a l a n c e c a l c u l a t i o n s  (Appendix N)  itemizing  i n t o s o l u t i o n and subsequently p r e c i p i t a t e d , may than 100% i n two  as the  Fe  extracted  Fe  brought  total  greater  i s e f f e c t i v e l y measured twice  d i f f e r e n t forms.  2. B a s a l t Oxalate P r e c i p i t a t e Magnification  under the  scanning e l e c t r o n  microscope  of the p r e c i p i t a t e formed from o x a l i c a c i d l e a c h i n g o f b a s a l t i s shown i n F i g u r e Mg  and  Fe.  XRF  i n d i c a t e d the weathered  31.  highest  product  show the  (Appendix  I) 2  under  all  highest  organic  complexes with  precipitate  (14.63%), of  experimental  level  r e f l e c t s the oxalic  of e x t r a c t a b l e  f a c t t h a t the Fe acid.  any  conditions.  (5.5%) are g r e a t e r than the F e  Fe  QX  p y R 0  (25%)  i s bound i n  Surprisingly,  the  Fe  CB0  l e v e l s (2.0%) p o i n t i n g  t o the presence of some c r y s t a l l i n e Fe. XRD 2  3  the  (summarized i n the bar graph i n Appendix  sample and  K)  of  accumulation of Fe 0  f o r any  levels  a n a l y s e s produced major peaks f o r  analysis  Sesquioxide a n a l y s i s A.,) , a l s o  EDX  analysis  (Appendix  i d e n t i f i e d major peaks f o r F e - o x a l a t e hydrate, Mg-oxalate  hydrate, c a l c i u m o x a l a t e ,  o x a l i c a c i d as w e l l as pyroxene  and  f a y a l i t e . Once again, the y e l l o w c o l o u r of the p r e c i p i t a t e i s a l s o i n d i c a t i v e of the F e - o x a l a t e hydrate (Handbook of P h y s i c s and  Chemistry, 1986).  101  3a. G r a n o d i o r i t e  Citrate Precipitate  The c r u s t - l i k e m a t e r i a l which s e t t l e d out upon d r y i n g i n the g r a n o d i o r i t e batch sample a f t e r 11 weeks o f weathering examined under the scanning e l e c t r o n microscope ( F i g u r e At 700 and HOOx m a g n i f i c a t i o n an amorphous m a t e r i a l ,  was 33).  "fluffy"  i n appearance, i s seen t o adhere t o m i n e r a l p a r t i c l e s . EDX 8000x m a g n i f i c a t i o n , consisted  of  Fe  (Figure 32)  and  material an  than  other  t h a t the  material  a minor amount of S i . T h i s  l i k e l y accounts f o r the higher  revealed  fact that Fe  forms  of  p Y R 0  at  formation  l e v e l s were s l i g h t l y  extractable  Fe  in  the  crust  (Appendix A. ) . XRF a n a l y s i s of t h i s m a t e r i a l showed 2  accumulation  of  Fe 0 2  (6.5%)  3  compared  with  that  of  unweathered g r a n o d i o r i t e (5.21%). In c o n t r a s t the p r e c i p i t a t e from  oxalic acid  leaching  contained  16.22%  Fe 0 . 2  c i t r a t e p r e c i p i t a t e , although predominantly Fe, a much l e s s e r extent  for  the  a n a l y s i s d i d not produce any  l i m i t s . There was  hematite  peak  Granodiorite Coatings  on  (Appendix  surface  increase  K ) , but 2  peaks f o r  the  in intensity hematite  is  not a secondary p r o d u c t .  C i t r a t e Inorganic the  crust.  have e x i s t e d but were below  a slight  l i k e l y of l i t h o g e n i c o r i g i n and  3b.  developed to  formed o n l y a small p a r t of the  c a t i o n - c i t r a t e complexes which may detectable  the  or at a slower r a t e than t h a t developed  under o x a l i c a c i d and In a d d i t i o n , the XRD  Thus  3  of  Surface  Coatings  granodiorite  particles  weathered by c i t r i c a c i d , d i f f e r i n g i n appearance from  the  7-hov-19Se  11:41.lb  Citric  acid  500  Vert-  "Crust"  counts  Disp-  1  Preset •  200  sees  E1apsed•  200  sees  Tt-  (N O  i  /Sl :  0.000  Range•  "  10.230 keV  Integral  Figure  32: EDX o f s a m p l e s h o w n i n F i g u r e 33.  9.750 0  ->  15825  Figure  33: A m o r p h o u s p r e c i p i t a t e i n g r a n o d i o r i t i c c r u s t formed a f t e r 11 weeks o f l e a c h i n g i n c i t r i c acid. 1100 x m a g n i f i c a t i o n  I  103  sample noted above, were a l s o observed i n the m a t e r i a l which s e t t l e d coating  was  upon d r y i n g . T h i s  photographed  microscope and Both  out  under  i s shown i n F i g u r e  500  and  800x  the  finer "crust" second type  scanning  electron  revealed  amorphous  35.  magnification  s u r f a c e m a t e r i a l c o a l e s c i n g between p a r t i c l e s . at  800x m a g n i f i c a t i o n  and  penetrating  showed major peaks f o r S i , A l and g i v e n by the r e l a t i v e h e i g h t s 1.4.  2um  EDX  analysis  i n t o the  Fe. The  surface  r a t i o of Fe: A l as  of the peaks i s  In view of the f a c t t h a t Farmer and  approximately  Fraser  (1982), were  succesful i n synthesizing a stable Al 0 -Fe 0 -Si0 -H 0 s o l 2  4.5-5.0) w i t h  Fe:Al  molar r a t i o s up  t h a t the amorphous m a t e r i a l  of  3  2  3  t o 1.5,  2  2  (pH  i t i s possible  (See area A i n the photo) c o u l d  be s i m i l a r i n make-up. As r e p o r t e d however , by McBride e t a l . (1984), F e gel  3+  tends not t o s u b s t i t u t e randomly i n an  Al-Silica  but r a t h e r aggregates i n t o c l u s t e r e d F e - r i c h phase i n the 3 +  form of f e r r i c o x i h y d r o x i d e w i t h i n the g e l . The F e - r i c h phase forms a p r e c u r s o r t o f e r r i h y d r i t e and the A l - S i r i c h phase a precusor  to proto-imogolite.  The  formation  the removal of the sample. A  small  of t h i s g e l l i k e l y occurred .1M  c i t r i c a c i d s o l u t i o n (pH 2.5)  u n i t of r e s i d u a l c i t r i c  m i n e r a l p a r t i c l e s and may At  first,  acid  subsequent t o from the  a c i d d r i e d on  be observed i n Area B o f the photo.  the presence o f a s t r o n g c h e l a t o r , such as  citric  i n such h i g h c o n c e n t r a t i o n , would seem t o p r e c l u d e  chances  of  sesquioxides  the  forming  at  a l l . Note  that  Al  the in  Figure  34: EDX o f sample shown i n F i g u r e 35.  F i g u r e 35: G r a n o d i o r i t i c " c r u s t " l e a c h e d i n c i t r i c a c i d f o r 11 weeks. 500 x m a g n i f i c a t i o n  105  organic  complexes,  orthosilicate  for  example,  (Buurman and Vav  is  more  stable  Reeuwijk, 1984).  i n mind t h a t most o f the s o l u t i o n was  removed and  than  in  But  bearing  the  samples  were l e f t t o a i r - d r y over the course of s e v e r a l weeks, i t i s ,  possible  to  trace  noted by  Farmer  undersaturated metal:fulvate through  formation  (1979), metal with  metals  by  of  these  fulvates  but  become  r a t i o r i s e s to saturation.  centrifugation  effectively ligand  the  separated reducing  followed much  the  of  precipitates.  remain s o l u b l e insoluble  the  Removal o f s o l u t i o n  organic  ligand:metal  when  when  by . a i r - d r y i n g  the  As  may  phase  ratio.  have  from  the  Secondly,  the  amount of c i t r a t e , at f i r s t c o - p r e c i p i t a t e d w i t h a metal, w i l l decrease upon aging ( V i o l a n t e and Huang, 1984). The l i b e r a t i o n of the o r g a n i c anions w i t h time i n the l a b o r a t o r y  experiments  of V i o l a n t e and Huang (1984), r e s u l t e d i n the f o r m a t i o n o f inorganic  precipitate.  Thirdly,  b i o l o g i c a l oxidation w i l l phase not  4.  (Buurman and  Basalt  microscope  conditions,  Reeuwijk, 1984). T h i s ,  inorganic  of course  column l a b o r a t o r y  was  experiments.  Citrate Precipitate  "fluffy"  basalt  field  separate the o r g a n i c from  a f a c t o r i n the batch and  No of  Van  under  an  with  p r e c i p i t a t e was citric  acid  d e t e c t e d from the weathering  under  the  scanning  (Figure 37). Rather, the r e l a t i v e EDX  crust material  showed an  electron  analysis  accumulation of s i l i c a w i t h only  of a  Basalt  grain  Vcr t=  under  citric  3t,U"5 c o u n t s  Sl  ;  acid  ['isp.  crust  Preset*  1  Elapsed  i:^:::::;.:i::::.::i:i:-!'i::i:!.-i::.!:t;:i:i  Wg . •  MjNa .  211. L!  il . L - l l i :  -r  Fei  »—r~——  l a . a r i u kt-v integral  Figure  36: EDX o f sample F i g u r e 37.  shown i n  0  Figure  37: B a s a l t i c g r a i n s l e a c h e d i n c i t r i c a c i d f o r 11 weeks. 150 x m a g n i f i c a t i o n  107  minor Fe peak (Figure 36) .The r e l a t i v e accumulation o f S i over t h a t of Fe i s r e f l e c t e d i n the SiOjj/RgOs r a t i o which from 3.61  i n the unweathered b a s a l t t o 4.05  increased  i n the weathered  c r u s t . S i m i l a r l y , Percentage of Fe^G^in weathered c r u s t dropped ., t o 7.04%  f o r B a s a l t A and  compared w i t h 12.4 6% added  that  the  even lower t o 3.69%  for Basalt  f o r the unweathered b a s a l t . I t might be  l e v e l s of  a l l forms  p r e c i p i t a t e d Fe  as  pyrophosphate e x t r a c t i o n s ,  as  oxalate,  w e l l as t o t a l Fe  i n the p r e c i p i t a t e as measured by  XRF  were  lowest of a l l 5 l e a c h i n g treatments f o r both column  batch t r i a l s . the  and  of  measured i n CBD,  the  B,  (Conversely,  and  S i O ^ R ^ s a n d AljOg/FegO^ratios were  highest.) The  all  amount of d i s s o l v e d Fe,  leaching  solution, ability  treatments.  f o r the  Clearly,  most p a r t ,  of c i t r a t e  on the  remained  t o m a i n t a i n Fe  other  the  hand exceeded  Fe  leached  in soluble  form.  i n s o l u t i o n leached  b a s a l t i s f a r g r e a t e r than the a b i l i t y of o x a l a t e molar  into The from  of s i m i l a r  concentration. Therefore,  although c i t r i c a c i d was  able to extract  g r e a t e r amounts of Fe from b a s a l t than from g r a n o d i o r i t e development of p r e c i p i t a t e s occured o n l y i n the samples.  granodiorite  As c i t r i c a c i d weathered the g r a n o d i o r i t e ,  of the  s o l u t i o n rose  only  citric  a c i d remains u n d i s s o c i a t e d  the  pH  this  pH  d i s s o l u t i o n of Fe  is  t o approximately and  2.3.  brought about more through a c i d o l y s i s ( i . e . H through c h e l a t i o n .  the  +  At  attack)  than  In c o n t r a s t , as c i t r i c a c i d weathered the  108  b a s a l t , the pH o f t h e s o l u t i o n rose t o approximately  3-5. A t  these h i g h e r pH's t h e Fe may be complexed t o e i t h e r HjjL'or t o 2HL  .  .  as each l i g a n d comprises  .  .  roughly 50% o f t h e c i t r i c  . acid.  The complexed Fe t h e r e f o r e remained i n s o l u b l e form. 5. G r a n o d i o r i t e - A c e t i c a c i d , HCl and HgO Leaching Treatments  G r a n o d i o r i t e leached i n a c e t i c and h y d r o c h l o r i c a c i d as  well  as d i s t i l l e d  development. weathered  XRF  water  data  were  showed  examined  a  g r a i n s but t o a much  drop  f o r sesquioxide  i n Fe20  lesser  3  extent  levels  than  in  either  c i t r i c o r o x a l i c a c i d treatments. EDX a n a l y s e s o f the c r u s t s resulting  from  acetic  acid  and d i s t i l l e d  water  treatments  showed o n l y a minor Fe peak o f l e s s e r i n t e n s i t y than those f o r S i , A l , Ca o r K. XRD a n a l y s e s o f c r u s t s from a l l 3 treatments i n d i c a t e d new peaks appearing a t 2.50, 2.21 and 1.96A . These 0  c o i n c i d e w i t h t h e peaks o f f e r r i h y d r i t e .  I t i s tempting t o  conclude t h a t , i n t h e absence o f s t r o n g e r o r g a n i c a c i d s such as  .1M  oxalic  and  citric  acids  which  may  inhibit  the  c r y s t a l l i z a t i o n o f Fe and A l oxides, f e r r i h y d r i t e c o u l d indeed form.  However,  Schwertmann  e t a l . (1982),  because o f i t s poor c r y s t a l l i n i t y  reported  ferrihydrite  that  can only be  r e c o g n i z e d e a s i l y by r o u t i n e XRD i f i t i s r e a s o n a b l y pure. To identify  i t i n lower c o n c e n t r a t i o n s as found  mixtures w i t h o t h e r m i n e r a l s special  procedures  such  i n s o i l s or i n  (e.g. q u a r t z , micas,  as DXRD and Mossbauer  goethite),  spectroscopy  109  must be  a p p l i e d . The  authors  found  t h a t the  lower  limit  of  Fe  and  f e r r i h y d r i t e d e t e c t i o n l i e s somewhere between 13.3% 2.9%  Fe .  Fe  ox  levels  ox  including  crust  inorganic  treatments.  The  photograph  microscope, as  were  recorded  f o r the  appriximately  in  Figure  39,  c l e a r l y shows some form  weathered  1%  or  taken  less  ox  residues  for a l l 3  under  the  light  of Fe oxide development  i n d i c a t e d by the darker orange areas  i n tha g r a i n s of a  g r a n o d i o r i t i c sample leached i n water. These c o a t i n g s were not , however, analyzed i n f u r t h e r  6. B a s a l t - A c e t i c a c i d , HC1  detail.  and H 0 2  Leaching Treatments  XRF data f o r b a s a l t leached by the 3 n o n - c h e l a t i n g a c i d s gave o n l y a s l i g h t Levels  f o r Si02  leaching.  In  drop  and  A1 0 2  addition,  i n Fe 0 2  3  3  i n the weathered r e s i d u e s .  remained about the same f o l l o w i n g XRD  analyses  did  not  detect  the  development of any new peaks.This i s c o n s i s t e n t w i t h the very low s o l u b i l i t y of Fe, S i and A l oxides  , even a t low pH,  an a q u a t i c environment d e p l e t e of s t r o n g l y complexing acids.  XRF  analyses  i n c r e a s e i n % A1 0 2  3  of  the  crust  material  and a s l i g h t decrease  gave  i n % Fe 0 2  in  organic a  3  slight  compared  w i t h both the unweathered and weathered r e s i d u e s . Data Al  o x C 8 D  f o r e x t r a c t a b l e Fe  and  A l showed Fe  ox C B D  and  l e v e l s h i g h e r than those f o r the c i t r i c and o x a l i c a c i d  treatments. T h i s i s s u r p r i s i n g i n l i g h t of the f a c t t h a t  110  Figure 39: G r a n o d i o r i t i c grains leached i n H 0 f o r 11 weeks. Note Fe o x i d a t i o n i n centre of photograph 200 x m a g n i f i c a t i o n 2  Ill  c i t r i c and o x a l i c a c i d have a much h i g h e r e x t r a c t i o n c a p a c i t y for  Fe and A l than do a c e t i c a c i d , HCl and HgO. These  higher  than expected v a l u e s may be due t o an e r r o r i n measurement due t o t h e presence o f c o l l o i d a l p a r t i c l e s as d i s c u s s e d  earlier.  A l s o , much o f t h e Fe and A l e x t r a c t e d by t h e c h e l a t i n g a c i d s may be t i e d up i n o r g a n i c  a s s o c i a t i o n e i t h e r i n s o l u t i o n as  w i t h c i t r i c a c i d o r i n p r e c i p i t a t e as w i t h o x a l i c a c i d . On t h e other hand, any Fe o r A l , however l i t t l e , e x t r a c t e d from nonc h e l a t i n g agents may have adsorbed and o x i d i z e d v e r y onto t h e m i n e r a l  surface.  quickly  The photograph i n F i g u r e 38 shows  areas o f dark orange where Fe has o x i d i z e d onto t h e s u r f a c e of a b a s a l t i c g r a i n leached  7. Fe x" F e 0  The  C B D  i n water.  Ratios  graphic  display  o f data  showing  t h e percentage  e x t r a c t a b l e Fe r e v e a l s immediately a s u r p r i s i n g r e l a t i o n s h i p between F e g x  a n d  F e  CBD  l e v e l s  ' f ° both b a s a l t and g r a n o d i o r i t e r  samples i n a l l 5 l e a c h i n g treatments: Feox l e v e l s were higher than  FecBD l e v e l s  i n the majority  o f samples.  removes both p o o r l y and w e l l c r y s t a l l i z e d Fe oxides, r a t i o s n o r m a l l y should and  Day  Since Feox  CBD :Fe  CBD  not exceed u n i t y , Data from Mckeague  (1966), and S i n g l e t o n  (1978) , have r e v a l e d  typical  ranges f o r t h e main types o f s o i l h o r i z o n s between 0 and 1. S e v e r a l f a c t o r s c o u l d account f o r t h e r a t i o o f F e o x exceeding  unity  experiments. F i r s t  in  the  batch  of a l l , Feox  :Fe  and CBD  r a  column  tios  :Fe  CBD  weathering  may be g r e a t e r  112  than u n i t y due t o the presence of c r y s t a l l i n e magnetite. B a r i l and  Bitton  that  (1969), and McKeague  ammonium  e t a l , (1971a), have shown  oxalate solution  releases  Fe  from  magnetite  which i s Known t o be o n l y s p a r i n g l y s o l u b l e i n CBD (Gamble and D a n i e l s , 1972). R e s u l t s o f more r e c e n t work by Chao and Zhou (1983),  confirmed  the  observations  investigators that oxalic acid  made  by  i s particularly effective in  b r i n g i n g magnetites i n t o s o l u t i o n . The i n c l u s i o n , of  detrital  magnetites  with  earlier  amorphous  iron  therefore,  oxides  could  confound  t h e use and i n t e r p r e t a t i o n of d a t a on a c t i v e  ratios.  The  presence  of  magnetite  in  both  basalt  iron and  g r a n o d i o r i t e was confirmed by XRD a n a l y s e s . Secondly, CBD d i s s o l v e s Fe from f i n e p a r t i c l e s o f l a b i l e s i l i c a t e s but f a i l s iron  oxides  t o d i s s o l v e completely some c r y s t a l l i n e  particles  coarser  than  approximately  50  um  (Pawluk, 1972; McKeague and S c h u p p l i , 1985). F o r t h i s reason Schwertmann  and  Taylor  suggest  that  coarse  samples  may  r e q u i r e s e v e r a l treatments o f CBD e x t r a c t a n t . C o n s i d e r i n g t h a t samples  were  leached from  crushed  basalt  and  granodiorite  whose p a r t i c l e s i z e l a y between 100 and 500um i t i s p o s s i b l e t h a t FecBD l e v e l s were underestimated. T h i r d l y , a c i d ammonium o x a l a t e can d i s s o l v e  significant  amounts o f Fe from o r g a n i c complexes (McKeague, 1967; McKeague et  a l . 1971;  Schwertmann,  1973).  There  i s , therefore,  a  tendency f o r t h e Feox* C B D r a t i o t o i n c r e a s e w i t h i n c r e a s i n g Fe  C c o n t e n t (Campbell and Schwertmann, 1984). Research has shown  113  that  o x a l a t e - e x t r a c t a b l e Fe  and  Al  commonly  exceed  e x t r a c t a b l e Fe and A l i n B h o r i z o n s of O r t h i c Humic (McKeague and  the  presence o f metal o r g a n i c complexes c o u l d have weighted  the  in  1966;  Podzols  S i n g l e t o n , 1978). A c c o r d i n g l y ,  results,  Day,  CBD-  the  batch  and  column  experiments,  for  those  samples leached by o r g a n i c a c i d s i n c o n t r a s t t o those samples l e a c h e d by HC1  and  H 0. 2  A f o u r t h f a c t o r t o c o n s i d e r i s t h a t of time. Aging as an important  parameter  compounds has a  i n the  been e s t a b l i s h e d by Hsu  c h r o n o l o g i c a l sequence,  more  long-range  experiment,  crystallization  order,  of  sesquioxide  and Ragone  (1972). In  amorphous forms precede those  and  could  have  accounted,  in  f o r a l a r g e component of the s e s q u i o x i d e s  of  this which  formed. In  differential  dissolution  methods used i n s o i l s work, both o x a l a t e and CBD  methods are  largely  addition,  emperical.  separate  sharply  as  In Fe  with  other  fact, in  they  iron  cannot  oxides  be  from  expected Fe  in  to  other  combinations and p a r t i c u l a r l y amorphous from c r y s t a l l i n e forms because  they  therefore,  may  are  a l l part  not  of  have given  a a  continuum. "true  The  " indication  results, of  the  r e l a t i v e ,amounts of each Fe form. Finally,  as  mentioned p r e v i o u s l y , the  c o l l o i d a l m a t e r i a l i n t o s o l u t i o n may atomic a b s o r p t i o n spectrophotometric  i n t r o d u c t i o n of  have overestimated readings. I t i s  the  114  recommended t h e r e f o r e t h a t e x t r a c t a n t s be passed through a 20 um f i l t e r paper p r i o r t o AA a n a l y s e s .  8. A d d i t i o n a l Notes  a) S e s q u i o x i d e formation a f t e r 4 weeks o f l e a c h i n g was as high or  h i g h e r than a f t e r 11 weeks o f l e a c h i n g f o r most samples,  basalt  and  granodiorite,  experiments.  for  both  column  According t o Schwertmann (1973),  and  batch  Fe on f r e s h l y  ground and exposed s u r f a c e s i s more e a s i l y d i s s o l v e d than from weathered s u r f a c e s commonly p r e s e n t i n s o i l s . I t appears t h a t the  r a t e o f formation  decreased  with  time  as the s u r f a c e  became coated w i t h the o x i d e s .  b)  It  is  generally  sesquioxide surface  the  coatings t o a mineral  charge  developed  acknowledged  of that  particle.  that  the  particle The pH  addition  will  of  a l t e r the  dependent  charge  l a r g e l y by amorphous c o a t i n g s may reduce the CEC of  underlying  (Hendershot  and  permanent Lavkulich,  negatively 1983).  This  charged  surface  phenomena  was not  apparent i n CEC data f o r b a s a l t and g r a n o d i o r i t e which showed a steady i n c r e a s e up t o 11 weeks.  c) In the batch and column d i s s o l u t i o n s t u d i e s , g r a n o d i o r i t e and in  basalt  o f heterogenous m i n e r a l composition  solutions  whose  chemical  make-up  varied  were leached as  weathering  115  proceeded.  The  environment pointed  formation  c o u l d not  out  precipitates  by  be  Holden  formed  of amorphous p r e c i p i t a t e s modelled (1983),  in  in a  the  simple  bulk  simulated  in this  f a s h i o n . As  compositions  mineral  of  dissolution  experiments are v e r y complex and c o n t i n u a l l y e v o l v e d u r i n g the course o f a r e a c t i o n as pH and redox c o n d i t i o n s s h i f t .  The  presence o r absence of s a l t and o t h e r n u c l e a t i o n s i t e s on the m i n e r a l s u r f a c e may and  the  number  be important i n i n i t i a t i n g  of  such  sites  is  not  precipitation  fixed  over  time.  Competition between ions f o r r e a c t i v e s i t e s or i n o t h e r words the c o m p e t i t i o n between Lewis a c i d s f o r Lewis bases and versa,  f u r t h e r complicates any  attempt  vice  t o model p r e c i p i t a t e  f o r m a t i o n from a very mixed i o n i c s o l u t i o n .  In f a c t , p r e v i o u s  s t u d i e s of a l u m i n o - s i l i c a t e p r e c i p i t a t i o n which have been used to  suggest  compositions,  that  (Kittrick,  compositions  which  surrounding  medium  question  precipitates  in light  should  form  1970;Bussenburg,  are determined (Paces,  1978)  of Holdren's  solely have  with  1978), by  the  been  fixed  or pH  of  thrown  more r e c e n t work.  with  In  the into this  c u r r e n t study, f u r t h e r a n a l y t i c a l work i s needed t o f i r s t a l l determine  q u a n t i t a t i v e l y the p r e c i s e chemical make-up of  the p r e c i p i t a t e s and  of  i n c l u d i n g the molar r a t i o s of each element  o r g a n i c l i g a n d . Only then can f u r t h e r s t e p s be taken t o  the s o l u b i l i t y product constant which, i n a d d i t i o n t o the i o n a c t i v i t y product Index  (IAP) can be used t o formulate the S a t u r a t i o n  f o r each compound. T h i s i s not  such  an  easy  task  as  116  r e l i a b l e aqueous a c t i v i t i e s o f ions must f i r s t be c a l c u l a t e d . This  i n v o l v e s c o r r e c t i o n s f o r i o n p a i r i n g and complexing as  w e l l as a c t i v i t y - c o e f f i c i e n t can be v e r y d i f f i c u l t , system.  c a l c u l a t i o n s . These c o r r e c t i o n s  r e q u i r i n g the use of a l a r g e computor  117  S U M M A R Y Two  simulated  (shaking)  A N D  C O N C L U S I O N S  weathering  and column  experiments,  (gravity)  namely  were designed  batch  t o study the  ., d i s s o l u t i o n o f crushed b a s a l t and g r a n o d i o r i t e i n t h e presence of  3  organic  and  2  inorganic  acids.  Chemical  m o r p h o l o g i c a l changes i n the m i n e r a l r e s i d u e s and  11 weeks of weathering were examined.  leachate  chemistry and r a t e s  a f t e r 4 weeks  Changes i n both  of d i s s o l u t i o n , as r e v e a l e d  s o l u t i o n a n a l y s e s were a l s o noted, as w e l l  and  by  as t h e formation  of p r e c i p i t a t i o n products.  1.  Chelation  and S t a b i l i t y Constants  F i r s t of a l l , s o l u t i o n analyses show t h a t t h e d i s s o l u t i o n of ions from g r a n o d i o r i t e , by the l e a c h i n g treatment shown i n parentheses, decreased i n the f o l l o w i n g  order:  Fe(OX) > A1(0X) ~ Si(OX) > Ca(CIT) - Mg(OX) ~ K(OX) > Na(OX) Dissolution following Fe(CIT)  of  ions  from  basalt  decreased  i n the  order:  > Si(CIT)  > Mg(CIT)  > Ca(CIT)  > A1(0X, ACETIC) >  Na(OX) > K(HC1) In analysis  the weathered revealed  granodioritic  significant  solutions,  difference,  statistical at  the  95%  c o n f i d e n c e l e v e l between c i t r i c and o x a l i c a c i d s o l u t i o n s as well  as between the c h e l a t i n g  multi-valent  s o l u b i l i z e d ions.  and n o n - c h e l a t i n g Also  acids f o r  levels of s o l u b i l i z e d  118  ions  i n water were s i g n i f i c a n t l y lower than  treatments.  There  was  no  for  a l l other  significant difference  a c e t i c a c i d HCl treatments f o r d i s s o l v e d Ca, Mg,  Na,  K and  Fe.  a t the  95%  s i g n i f i c a n t d i f f e r e n c e between c i t r i c  and  In the weathered b a s a l t i c s o l u t i o n s , t h e r e was confidence l e v e l ,  between  o x a l i c a c i d s o l u t i o n s f o r Ca, Mg,  Fe, A l and  Si.  In  addition  s i g n i f i c a n t d i f f e r e n c e s occurred between a l l 5 l e a c h a t e s f o r d i s s o l v e d Fe and Mg. between o x a l i c and between  oxalic,  A l s o there were s i g n i f i c a n t d i f f e r e n c e s acetic acid  acetic  acid  solutions  and  HCl  for dissolved  for  dissolved  between a c e t i c a c i d and HCl f o r d i s s o l v e d S i . with granodiorite  l e v e l s of  As was  s o l u b i l i z e d ions  Al  Ca, and  the case  i n water were  s i g n i f i c a n t l y lower than f o r a l l other treatments.  There were  however i n s i g n i f i c a n t d i f f e r e n c e s f o r d i s s o l v e d Na amongst a l l l e a c h a t e s except water. the  case  of  granodiorite  leachates revealed Oxalic  The  where  citric  for K and  +  except i n  oxalic  acid  h i g h l e v e l s of s o l u b i l i z e d K.  a c i d e f f e c t i v e l y outcompeted c i t r i c  weathering of g r a n o d i o r i t e c o n s t a n t s f o r most i o n s . as  same held t r u e  many weathering  acid  in  the  i n s p i t e of having lower s t a b i l i t y T h i s r e s u l t was  experiments reported  somewhat s u r p r i s i n g i n the  literature,  p o i n t t o a c o r r e l a t i o n between the e f f i c a c y of an o r g a n i c a c i d in  extracting  with that ion. both  batch  chelating  ions  from a mineral to i t s s t a b i l i t y  constant  A c l o s e r i n s p e c t i o n of a l l a v a i l a b l e data from  and acids,  column experiments showed t h a t the  ability  of the  f o r the  acid to extract  an  two ion  119  ultimately acids.  depend  on  solution  pH  and  on  the  pKa's  Formation curves were used i n e s t i m a t i n g  the  of  the  degree  of d i s s o c i a t i o n (and percentage of each l i g a n d formed) f o r the pH  of  the  leaching  approximately 2.2,  solution.  c i t r i c a c i d (pK  In o t h e r words the from  the  mineral  I t was  H  ion could  +  surfaces  shown t h a t  = 3.14)  1  was  Lewis  base  metal  citrate  O x a l i c a c i d (pK, = 1.23), on the other hand, was 80%  d i s s o c i a t e d a t pH < 2 and  to  form  chelates.  It  d i s s o c i a t i o n constants may  of  cation ligand.  approximately  the c i t r a t e anion was  i s concluded,  pH  undissociated.  outcompete any  for  at  available  therefore,  that  be more important than  acid  stability  c o n s t a n t s per se i n determining the r e l a t i v e d i s s o l u t i o n power of an o r g a n i c a c i d at a p a r t i c u l a r  pH.  Evidence from s o l u t i o n AA analyses and XRD the  effectiveness  might a l s o solution ions  be  explained  parent  a c t i v e surface It  of o x a l i c a c i d i n weathering  for ligand  i n the  is  on  sites,  the  basis  as  for  environment both the p h y s i c a l and  scrutinized of o r g a n i c  well  area of the parent that  the  as  granodiorite  ion competition  in  oxidation  of  state  particle size  and  material. any  particular  weathering  chemical components of  chemical make-up of the  i n order t o e x p l a i n acids.  of  geometry and  material  concluded  m i n e r a l ( s ) and  indicated that  s o l u t i o n must  d i s s o l u t i o n i n the  the be  presence  120  2.  C h e l a t i o n and A l k a l i Metals There  was  c h e l a t i o n of K In  fact,  into  +  no  conclusive  or N a  +  took p l a c e i n any  of  citric  and  other  AA  s o l u t i o n analyses,  indicate  o f the  leaching  oxalic acid to  l e v e l s of K from g r a n o d i o r i t e was, and  to  i n the weathering of b a s a l t , HCl  s o l u t i o n than d i d any  ability  evidence  experiments.  e x t r a c t e d more K treatment.  extract  the  3.  on the b a s i s o f SEM,  attributed to  the  breakdown  of  and  Fe,  mass balance c a l c u l a t i o n s , XRF  and  Chelation vs. Acid D i s s o l u t i o n ratios,  of unweathered and weathered rock as w e l l as AA s o l u t i o n  analyses and  EDX  subsequent r e l e a s e of K from the i n t e r l a y e r s .  Molar oxide EDX  The  highest  b i o t i t e i n i t i a t e d by c h e l a t i o n of o r g a n i c a c i d t o Mg with  that  showed t h a t s t r o n g l y c h e l a t i n g a c i d s such as  o x a l i c a c i d g r e a t l y outcompeted a c e t i c a c i d and  s i m i l a r pH evident were  for multi-valent cations.  f o r A l , Fe  many-fold  and  T h i s was  S i whose c o n c e n t r a t i o n s  higher  than  concentrations  e q u i l i b r i u m with the amorphous oxides.  citric HCl  of  particularly in solution in  water  in  This i s a t t r i b u t e d to  the a b i l i t y of c i t r i c and o x a l i c a c i d s t o complex metals  and  therefore  the  extent  of  increase  the  domain of weathering.  complexation  determined by pH. s o l u t i o n and pKa  for  any  given  However,  chelate  is  also  As noted above, depending on the pH of the of the c h e l a t i n g a c i d both a c i d a t t a c k of a  m i n e r a l s u r f a c e through i o n exchange and complexation between  121  mineral  and  simplistic  anion to  may  rely  on  occur the  concurrently. use  of  It  is  complexation  rather  index  as  i n t r o d u c e d by Razzaghi-Karimi and Robert (1979) whereby v a l u e s g r e a t e r than 1 f o r R _  R  indicate  Amount of element r e l e a s e d by o r g a n i c a c i d Amount of element r e l e a s e d by HC1  chelation.  quantitatively  the  There extent  is  a  need  to  determine  of d i s s o c i a t i o n of  the  more  chelating  a c i d and t h e r e f o r e the extent to which c h e l a t i o n competes w i t h or i s superimposed on a c i d o l y s i s .  4.  K i n e t i c s of D i s s o l u t i o n A  study  granodiorite curves  of  showed t h a t o x a l i c and  were  followed  by  towards  the  microscopic  k i n e t i c s of weathering  characterized  by  d e c l i n i n g rates eleventh (SEM)  week  citric  initially  which of  of  both  and  acid dissolution increasing  approached  the  basalt  rates  steady  experiment.  state  Electron  evidence of h y p e r f i n e p a r t i c l e s adhering t o  m i n e r a l s u r f a c e s supported the theory t h a t r a p i d i n i t i a l r a t e s of weathering were due a r t i f a c t s of g r i n d i n g . from EDX  analyses  to the breakdown of these v e r y Evidence of a leached  of b a s a l t and  surface  g r a n o d i o r i t e , might  small layer,  explain  the approach towards steady s t a t e k i n e t i c s a f t e r 11 weeks of dissolution. of  charge  solution  and  T h i s c a t i o n depleted structural strain  exposing  a  fresh  l a y e r w i t h i t s imbalance  may  surface  have broken down i n t o to  repeat  the  cycle  of  122  events.  The v e r y h i g h l e v e l s of S i brought i n t o s o l u t i o n  by  the d i s s o l u t i o n of b a s a l t by o x a l i c and c i t r i c a c i d p r o v i d e , indirectly, Finally  the  additional  evidence  build-up  of  ions  to  support  this  in  solution  as  theory. well  p r e c i p i t a t e s , i s c h a r a c t e r i s t i c of a c l o s e d weathering approaching e q u i l i b r i u m dissolution  as  system  with the s o l i d s t a t e whereby r a t e s of  decline.  Non-chelating  acids  such  as  acetic  acid,  HCl  and  H0 2  r e v e a l e d d i s s o l u t i o n curves t h a t were approximately constant (steady s t a t e ) throughout the 11 week weathering  experiments.  T h i s i s c h a r a c t e r i s t i c of an open system i n which the s o l u t i o n i s g r e a t l y undersaturated with r e s p e c t t o the s o l i d phase.  5.  Incongruent  Dissolution  Incongruent d i s s o l u t i o n was observed f o r g r a n o d i o r i t e basalt  weathered  by a l l 5 l e a c h i n g  treatments.  and  Incongruent  d i s s o l u t i o n was noted i n p a r t i c u l a r f o r c i t r i c a c i d treatments as evidenced by the a)  variable  following: but  dissolution b)  (AA s o l u t i o n  declining  rates  of  analysis)  changes i n molar r a t i o s of elements from unweathered to weathered  c)  predominantly  mass  balance  leaching  of  sample (from XRF  data)  calculations  showing  certain  elements  by  preferential  chelating  acids  (from AA s o l u t i o n analyses) d)  build  up  of p r e c i p i t a t e d  reaction  products  (XRD,  123  SEM, EDX, XRF and e x t r a c t a b l e Fe, A l , S i analyses) e)  leached Si  f)  residue  etch  pits  surfaces  6.  mineral  surface  layers with  predominantly  (EDX) and  other  d i s c o n t i n u i t i e s on  mineral  (SEM)  The Formation of P r e c i p i t a t i o n Products Citric  acid  was  less  e f f e c t i v e than  forming p r e c i p i t a t e s from g r a n o d i o r i t e .  oxalic  acid i n  However, EDX a n a l y s i s  of an amorphous ( p o s s i b l y organo) p r e c i p i t a t e which d i d form showed t h a t i t c o n s i s t e d o f p r i m a r i l y Fe. second  morphological  distinct  type  EDX a n a l y s i s o f a  of  amorphous  (likely  i n o r g a n i c ) c o a t i n g i n d i c a t e d predominantly S i and Fe i n a 1:1 ratio.  Although  citric  a c i d was  able  to extract  greater  amounts of Fe from b a s a l t than g r a n o d i o r i t e and even exceed all  e x t r a c t i o n treatments no i n o r g a n i c  p r e c i p i t a t e s were d e t e c t e d . i(CIT)(PYRO)(OX)  s  It  w  e  r  e  In f a c t e x t r a c t a b l e Fe, A l and  t h e lowest of a l l 5 l e a c h i n g  i s concluded t h a t the Fe e x t r a c t e d  or s o l u b l e solution.  o r organic-amorphous  form due t o t h e h i g h e r  pH  treatments.  remained i n complexed (3-5) o f t h e b a s a l t i c  A t t h e lower pH (2-3) o f the g r a n o d i o r i t e s o l u t i o n  the u n d i s s o c i a t e d  citric  a c i d was unable t o form F e - c i t r a t e  chelates. What appeared under t h e scanning e l e c t r o n microscope t o be  an  amorphous  precipitate  granodiorite with o x a l i c a c i d .  formed  from  the  leaching  of  EDX a n a l y s i s i n d i c a t e d t h a t  124  i t c o n s i s t e d p r i m a r i l y of S i and inorganic  and  discussed  in  formed  organic  consisted  components  some d e t a i l .  from the  leaching  p r i m a r i l y of Mg  experimental  Fe i n a 1:1  conditions  An of  precipitate  were  amorphous  precipitate  also  Fe  given  Possible  this  basalt  and  procedures, o x a l i c a c i d was  of  ratio.  with  oxalic  i n a 1:1  ratio.  with  both  batch  acid  which  Under and  the  column  more e f f e c t i v e than c i t r i c  acid  i n promoting the e a r l y stages of s e s q u i o x i d e development. The  dissolution  of  Fe,  Al  and  Si  from  basalt  g r a n o d i o r i t e by h o n - c h e l a t i n g agents such as a c e t i c a c i d , and  H0 2  was  limits).  s i g n i f i c a n t l y lower XRD  analysis  pointed  f e r r i h y d r i t e having formed on leached with a c e t i c a c i d , HCl F i n a l l y i t was in  both  Factors include: b)  batch  the and  to  C8D  possibility of  to  for the  crystalline procedures  d) and f)  limited  c)  contribution  measurements o f d i s s o l v e d  the  aging  amorphous  granodiorite,  of  detected colloidal  elements.  Fe  parent  presence  period  forms  most  high  a) the presence of magnetite i n the  precipitates  of  r a t i o s exceeded u n i t y  experiments  sample  confidence  2  have c o n t r i b u t e d  p a r t i c l e - s i z e of  HCl  H 0. 0X  column  95%  the  surfaces  noted t h a t F e / F e  and  which may  (within  and  e) by  of  samples. ox  levels rocks organic  overlap  of  analytical  matter  to  the  125  BIBLIOGRAPHY. Aagaard, P. and Helgeson, H.C. 1982. Thermodynamic and k i n e t i c c o n s t r a i n t s on r e a c t i o n r a t e s among m i n e r a l s and aqueous s o l u t i o n s . I . T h e o r e t i c a l c o n s i d e r a t i o n s . Amer. J . o f S c i . 282: 237-285. Anderson, H.A., Berrow, M.L., Farmer, V.C., Hepburn, A., R u s s e l l , J.D., and Walker, A.D. 1982. A reassessment o f podsol f o r m a t i o n p r o c e s s e s . J . of S o i l S c i . 33: 125-136. Baker, W.E. 1973. Role o f humic a c i d s from Tazmanium p o d z o l i c s o i l s i n m i n e r a l d e g r a d a t i o n and metal m o b i l i z a t i o n . Geochim. Cosmochim. A c t a 37: 269-281. B a r i l , R. and B i t t o n , G. , 1969. Teneurs e l e v e e s de f e r l i b r e e t i d e n t i f i c a t i o n taxonomique de c e r t a i n s s o l s du Quebeccontenant de l a magnetite. Can. J . S o i l S c i . , 49: 1-9. Bascomb, C.L. 1968. D i s t r i b u t i o n o f pyrophosphate e x t r a c t a b l e i r o n and o r g a n i c carbon from s o i l s o f v a r i o u s groups. J . o f S o i l S c i . 19: 251-268. Baudisch, 0. and A l b r e c h t , W.H. 943 .  1932. J . Amer. Chem. Soc.  54:  Beckwith, A.S. and Reeve, R.1964. S t u d i e s on s o l u b l e s i l i c a i n s o i l s . I I . The r e l e a s e o f m o n o s i l i c i c a c i d from s o i l s . Aust. J . of S o i l Res. 2: 33-45. Berner, R.A. 1981. K i n e t i c s of weathering and d i a g e n e s i s . P.111134. In Eds. Kasaga, A.C. and K i r k p a t r i c k , R.J. K i n e t i c s of Geochemical Processes. Reviews i n M i n e r a l o g y . Vol.8 M i n e r a l o g i c a l S o c i e t y o f America. Berner, R.A. and Schott, J . 1982. Mechanism o f pyroxene and amphibole weathering. I I . O b s e r v a t i o n o f s o i l g r a i n s . Amer. J . o f S c i . 282: 1214-1231. Bloom, P.R. and E r i c h , M.S. 1987. E f f e c t o f s o l u t i o n composition on the r a t e and mechanism o f g i b b s i t e d i s s o l u t i o n i n a c i d s o l u t i o n s . S o i l S c i . Soc. Amer. Proc. 51: 1131-1136. B l o o m f i e l d , C. 1981. The t r a n s l o c a t i o n of metal i o n s i n s o i l s . P.463-504. In Eds. Greenland, D.J. and Hayes, M.B.H. The Chemistry o f S o i l P r o c e s s e s . John Wiley and Sons, New York. Boyle, J.R., V o i g t , G.K. and Sawhney, B.L. 1967. B i o t i t e f l a k e s : a l t e r a t i o n by chemical and b i o l o g i c a l treatment. S c i e n c e 155: 193-195.  126  Blume, H.P., and Schwertmann, U. 1969. G e n e t i c e v a l u a t i o n o f profile distribution of aluminum, i r o n , and manganese o x i d e s . S o i l S c i . Soc. Amer. Proc. 33: 438-444. Borggaard, O.K. 1982. The i n f l u e n c e of i r o n oxides on t h e surface area o f s o i l s . J . of S o i l S c i . 33: 443-449. Borggaard,  O.K.  1987. C i t e d i n P a r f i t t and C h i l d s ,  1988.  Bremner, J.M. and Lees, H. 1949. S t u d i e s on s o i l o r g a n i c matter. P a r t I I . The e x t r a c t i o n o f o r g a n i c matter from s o i l by n e u t r a l reagents. J . A g r i c . S c i . 39: 274-297. Busenburg, E. 1978. The products of the i n t e r a c t i o n of f e l d s p a r s w i t h aqueous s o l u t i o n s a t 25 C. Geochim. e t Cosmochim. A c t a . 41-49. Busenburg, E. and Clemency, C. 1976. The d i s s o l u t i o n k i n e t i c s of f e l d s p a r s a t 25 C and 1 atmosphere C02 p a r t i a l p r e s s u r e . Geochim. Cosmochim. A c t a 40: 41-49. Buurman, P. and Van Reeuwijk, L.P. 1984. P r o t o - i m o g o l i t e and the p r o c e s s o f p o d z o l formation: a c r i t i c a l note. J . o f S o i l S c i . 35: 447-452. Campbell, A.S. and Schwertmann, U. 1984. I r o n oxide mineralogy of p l a c i c h o r i z o n s . J . o f S o i l S c i . 35: 569-582. Carroll,  D. 1970. Rock Weathering. Plenum, New York,  N.Y.  Chao, T.T. and L i y i Zhou. 1983. E x t r a c t i o n techniques f o r s e l e c t i v e d i s s o l u t i o n o f amorphous i r o n oxides from s o i l s and sediments. S o i l S c i . Soc. Amer. Proc. 47: 225-232. Chapman, H.D. 1965. In Methods of S o i l Analyses P a r t 2. Ed. Black, C A . Madison, Wisconson, U.S.A. C h i l d s , C.W. 1985. Towards understanding s o i l mineralogy. I I . Notes on f e r r i h y d r i t e . N.Z. S o i l Bureau L a b o r a t o r y Report 7, DSIR, New Zealand. C i t e d i n P a r f i t t and C h i l d s , 1987.  CM  Chou,L. and W a l l a s t , R. 1985. Steady - s t a t e k i n e t i c s and d i s s o l u t i o n mechanisms o f a l b i t e . Am. J . o f S c i . 285: 963-993. Colman, S.M. and P i e r c e , K.L. 1980. Weathering r i n d s on a n d e s i t i c and b a s a l t i c stones as a Quaternary age i n d i c a t o r , Western U n i t e d S t a t e s . U.S. Geol. Surv. P r o f . Paper 210. Colman, S.M. and D e t h i e r , D.P. 1986. Rates o f Chemical Weathering o f Rocks and M i n e r a l s . Academic Press Inc.  127  C o r n e l l , R.M. and Schwertmann, U. 1979. I n f l u e n c e o f o r g a n i c anions on c r y s t a l l i z a t i o n o f f e r r i h y d r i t e . C l a y s and Clay M i n e r a l s . 27: 402-410. Correns, C.W. and von Engelhardt, W. 1938. c i t e d i n W o l l a s t , R. and Chou, L. 1985. p.76. In the Chemistry o f Weathering. Ed. Drever, J . I . D. R e i d e l Pub. Co. Dordrecht, H o l l a n d . Correns, C.W. 1963. Experiments on t h e decomposition o f s i l i c a t e s and d i s c u s s i o n of chemical weathering. C l a y s and C l a y M i n e r a l s 12: 443-459. Curtis, CD. 1976. S t a b i l i t y o f m i n e r a l s i n s u r f a c e weathering reactions. E a r t h Surface Processes 1: 63-70. De Endredy, A.S. 1963. E s t i m a t i o n of f r e e i r o n oxides i n s o i l s and c l a y s by a p h o t o l y t i c method. C l a y Min. B u l l . 5: 209-217. D i b b l e , W.E. J r . and T i l l e r , W.A. 1981. N o n - e q u i l i b r i u m water/rock i n t e r a c t i o n s - 1. Model f o r i n t e r f a c e - c o n t r o l l e d r e a c t i o n s . Geochim. Cosmochim. Acta 45: 79-92. Dixon, J.B. and Jackson, M.L. 1962. P r o p e r t i e s o f i n t e r g r a d i e n t c h l o r i t e - e x p a n s i b l e l a y e r s i l i c a t e s i n s o i l s . S o i l S c i . Soc. Amer. Proc. 26: 358-362. Drever, J . I . 1982. The Geochemistry od N a t u r a l Waters. P r e n t i c e H a l l , Inc., N.J. Eckhardt, F.E.W. 1978. In Ed. Krumbein, W.G. Environmental Biogeochemistry and Geomicrobiology. Ann Arbor S c i . Pub. Ann Arbor, Michigan. Eggleton, R.A. and Boland, J.N. 1982. Weathering o f e n s t a t i t e t o t a l c through a sequence of t r a n s i t i o n a l phases. C l a y s and Clay M i n e r a l s 30: 11-20. Elgawhary, S.M. and Lindsay, W.L. 1972. S o l u b i l i t y s o i l s . S o i l S c i . S o c . Amer. Proc. 36: 439-442.  of s i l i c a i n  Eswaran, H., Stoops, G. and Sys, C. 1977. The micromorphology of g i b b s i t e forms i n s o i l s . J . S o i l S c i . 28:136-143. Farmer, V.C. 1979. P o s s i b l e r o l e s o f a mobile hydroxyaluminium orthosilicate complex (proto-imogolite) and other hydroxyaluminium and h y d r o x y - i r o n s p e c i e s i n p o d s o l i z a t i o n . Collogues i n t e r n a t i o n a u x du C.N.R.S. No.303275-279. Farmer, V.C. 1984. D i s t r i b u t i o n of a l l o p h a n e and o r g a n i c matteri n podzol B h o r i z o n s : r e p l y t o Buurman & Van Reeuwijk. J . of S o i l S c i . 35: 453-458.  128  Farmer, V.C. and F r a s e r , A.R. 1982. Chemical and c o l l o i d a l s t a b i l i t y o f s o l s i n the AlgO^-FegC^-SiG^-HgOsystem: t h e i r r o l e i n p o d z o l i z a t i o n . J . o f S o i l S c i . 33: 737-742. Farmer, V . C , R u s s e l l , J . D . and Smith, F.L. 1983. E x t r a c t i o n of i n o r g a n i c forms of t r a n s l o c a t e d A l , Fe, and S i from a podzol Bs h o r i z o n . J . o f S o i l S c i . 34: 571-576. .t  Farmer, V . C , McHardy, W.J. , Robertson, L., Walker, A. and Wilson, M.J. 1985. Micromorphology and sub-microscopy of a l l o p h a n e and i m o g o l i t e i n a podzol Bs h o r i z o n : evidence f o r t r a n s l o c a t i o n and o r i g i n . J . o f S o i l S c i . 36: 87-95. Fey, M.V. and Le Roux, J . 1961. The isomorphous relacement o f i r o n by aluminum i n s o i l g o e t h i t e s . J . S o i l S c i . 12: 294-306. F i s c h e r , W.R. and Schwertmann, U. 1975. The f o r m a t i o n o f hematite from amorphous i r o n ( I I I ) hydroxide. C l a y s Miner. 23: 33-37.  Clay  F o l l e t , E.A.C. 1965. The r e t e n t i o n of amorphous c o l l o i d a l " f e r r i c hydroxide" by k a o l i n i t e s . J . S o i l S c i . 16: 334-331. Fordham, A.W. and N o r i s h , K. 1983. The nature o f s o i l p a r t i c l e s p a r t i c u l a r l y those r e a c t i n g with arsenate i n a s e r i e s o f c h e m i c a l l y t r e a t e d samples. Aust. J . S o i l Res. 21: 455-477. F u r r e r , G. and Stumm, W. 1983. The r o l e o f s u r f a c e c o o r d i n a t i o n i n t h e d i s s o l u t i o n o f 5 - A I 2 O 3 i n d i l u t e a c i d s . Chimia 37: 338341. F r i t z , B. 1985. Multicomponent s o l i d s o l u t i o n s f o r c l a y m i n e r a l s and computor m o d e l l i n g of weathering p r o c e s s e s , p. 19-34. I n The Chemistry o f Weathering. Ed. Drever, J . I . D. R e i d e l Pub. Co. Dordrecht, H o l l a n d . Gardner, L.R. 1983. Mechanics and k i n e t i c s o f incongruent f e l d s p a r d i s s o l u t i o n . Geology 11: 418-421. G a r r e l s , R.M. and Howard, P. 1959. Reactions of f e l d s p a r s and mica w i t h water a t low temperature and p r e s s u r e . C l a y s and C l a y M i n e r a l s 6:68-88. G i l k e s , R.J. and Suddhiprakarn, A. 1979. B i o t i t e a l t e r a t i o n i n deeply weathered g r a n i t e . I . M o r p h o l o g i c a l , m i n e r a l o g i c a l and c h e m i c a l p r o p e r t i e s . C l a y s and Clay Min. 27: 349-360. Glemser, 0. 1938. Ber. Dtsch. Schulemborgh, J . 1964.  Chem. Ges. 71:158.  Cited  i n Van  129  Handbook o f Chemistry and P h y s i c s , 58th E d i t i o n , 1977-1978. Ed. Weast, R.C. CRC Press, Inc. C l e a v e l a n d , Ohio. G r a n d s t a f f , D. 1977. Some k i n e t i c s o f b r o n z i t e orthopyroxene d i s s o l u t i o n . Geochim. Cosmochim. A c t a 41: 1097. G r a n d s t a f f , D. 1977. Changes i n s u r f a c e area and morphology and the mechanism o f f o r e s t e r i t e d i s s o l u t i o n . Geochemi. e t Cosmochin. A c t a 42: 1899-1901. G r a n d s t a f f , D. 1986. The d i s s o l u t i o n r a t e o f f o r s t e r i t i c o l i v i n e from Hawaiian beach sand. In Rates o f Chemical Weathering o f Rocks and M i n e r a l s . Eds. Colman, S.M. and D e t h i e r , D.P. Academic Press, I n c . Grant, W.H. 1963. Weathering o f Stone Mountain g r a n i t e . C l a y M i n e r a l s 11: 65-73.  C l a y s and  G r a u s t e i n , W.C., Cromack, K. J r . and S o l i i n s , P. 1977. Calcium o x a l a t e : occurence i n s o i l s and e f f e c t on n u t r i e n t and geochemical c y c l e s . S c i e n c e 198: 1252-1254. Hegelson, H.C, Murphy, W.M. and Aagaard, P. 1984. Thermodynamic and k i n e t i c c o n s t r a i n t s on r e a c t i o n r a t e s among m i n e r a l s and aqueous s o l u t i o n . Geochim. Cosmochim. Acta 48: 2405-2432. Heilman, M.D., C a r t e r , D.L. and Gonzales, C.L. 1965. The ethylene glycol monoethyl ether (EGME) technique determining s o i l s u r f a c e a r e a . S o i l S c i . 100: 409-413.  for  Henderson, M.E.K. and Duff, R.B. 1963. The r e l e a s e o f m e t a l l i c and s i l i c a t e i o n s from m i n e r a l s , rocks and s o i l s by fungal a c t i v i t y . J . o f S o i l S c i . 33: 115-124. Helgeson, H.C. 1971. K i n e t i c s o f mass t r a n s f e r among s i l i c a t e s and aqueous s o l u t i o n s . Geochim. e t Cosmochim. Acta 35: 421469. Holdren, G.R. and Berner, R.A. 1979. Mechanism o f f e l d s p a r weathering - I . Experimental S t u d i e s . Geochim. e t Cosmochim. A c t a 43: 1161-1171. Holdren, G.R. 1983. The composition o f e a r l y formed a l u m i n o s i l i c a t e p r e c i p i t a t e s : r e s u l t s from simulated f e l d s p a r d i s s o l u t i o n s t u d i e s . S c i . Geol. Mem..71: 75-84. Holdren, G.R. and Speyer, P.M. 1985. pH dependent changes i n the r a t e s and s t o i c h i o m e t r y o f d i s s o l u t i o n of an a l k a l i f e l d s p a r a t room temperature. Am. J . o f S c i . 285: 994-1026.  130  Holdren, G.R. and Speyer, P.M. 1986. S t o i c h i o m e t r y o f a l k a l i f e l d s p a r d i s s o l u t i o n . In Rates o f Chemical Weathering o f Rocks and M i n e r a l s . Ed colman, S.M. Academic P r e s s , I n c . p.61-81. H o s t e t t e r , P.B. and C h r i s t , C.L. 1968. S t u d i e s i n t h e system MgO-Si02-C02-H20. I . The a c t i v i t y - p r o d u c t c o n s t a n t c h r y s o l i t e . Geochim. Cosmochim. A c t a 32: 485-497. Hsu,  of  P.H. 1977. Aluminum hydroxides and oxyhydroxides. P. 99143. In Eds. Dixon, J.B. and Weed, S.B. M i n e r a l s i n S o i l Environments. S o i l S c i . Soc. o f Amer. Madison, W.I.  Huang, P.M. and V i o l a n t e , A. 1986. I n f l u e n c e o f o r g a n i c a c i d s on crystallization and s u r f a c e p r o p e r t i e s . o f p r e c i p i t a t i o n p r o d u c t s o f aluminum, p.159-221. In I n t e r a c t i o n s o f S o i l M i n e r a l s w i t h N a t u r a l Organics and Microbes. SSSA Spec. Pub. No. 17. Madison, W.I. Huang, W.H. and K e l l e r , W.D. 1971. D i s s o l u t i o n o f c l a y m i n e r a l s i n d i l u t e o r g a n i c a c i d s a t room temperature. Amer. M i n e r a l . 56: 1082-1085. Huang, W.H. and Kiang, W.C. 1972. L a b o r a t o r y d i s s o l u t i o n of p l a g i o c l a s e f e l d s p a r s i n water and o r g a n i c a c i d s a t room temperature. Amer. M i n e r a l . 57: 1849-1859. I l e r , R.K. 1979. The Chemistry o f S i l i c a , pp. 730-784. Wiley, York.  New  Jackson, M.L., Lim, C H . and Zeazny, L.W. 1986. Oxides, h y d r o x i d e s , and a l u m i n o s i l i c a t e s . Methods o f S o i l A n a l y s i s , P a r t 1. P h y s i c a l and M i n e r a l o g i c a l Methods-Agronomy Monograph no.9 (2nd E d i t i o n ) . Jeanroy, E. and G u i l l e t , B. 1981. The occurence o f suspended f e r r u g i n o u s p a r t i c l e s i n pyrophosphate e x t r a c t s o f some s o i l h o r i z o n s . Geoderma 26: 95-105. Jones, D., Wilson, M.G. and T a i t , J.M. 1980. Weathering o f b a s a l t by P e r t u s a r i a c o r a l l i n a . L i c h e n o l o g i s t 12: 277-289. K e l l e r , W.D. 1954. The bonding energy of some s i l i c a t e m i n e r a l s . Amer. Min. 39: 783-793. K e l l e r , W.D. 1957. P r i n c i p l e s o f Chemical Weathering. Lucas Bros. Pub. Columbia, M i s s o u r i .  I l l pp.,  K e r n d o r f f , H. and S c h n i t z e r , M. 1980. S o r p t i o n o f metals on humic a c i d . Geochimica e t Cosmochimica A c t a 44: 1701-1708. K i t t r i c k , J.A. 1970. P r e c i p i t a t i o n o f k a o l i n i t e a t 25 C and 1 atm. C l a y s and Clay M i n e r a l s . 18: 261-267.  131  Kodama,H. , S c h n i t z e r , M. and Jaakkimainen, M. 1983. C h l o r i t e and b i o t i t e weathering by f u l v i c a c i d s o l u t i o n s i n c l o s e d and open systems. Can J . o f S o i l S c i . 63: 619-629. Kononova, M.M. 1961. S o i l Organic Matter. Pergamon, New York, N.Y. Kwong, Ng Kee K.F. and Huang, P.M. 1975. I n f l u e n c e o f c i t r i c on t h e c r y s t a l l i z a t i o n o f aluminum h y d r o x i d e s . C l a y s Miner. 23: 164-165.  acid Clay  Kwong, Ng Kee K.F. and Huang, P.M. 1977. I n f l u e n c e o f c i t r i c a c i d on t h e h y d r o l y t i c r e a c t i o n s o f aluminum. S o i l S c i . Soc. of Amer.Proc. 41: 692-697. Kwong, Ng Kee K.F. and Huang, P.M. 1979. Nature o f h y d r o l y t i c p r e c i p i t a t i o n p r o d u c t s o f aluminum as i n f l u e n c e d by lowm o l e c u l a r weight complexing o r g a n i c a c i d s , p.527-53 6. In Eds. Mortland. M.M. and Farmer, V.C. I n t e r n a t i o n a l C l a y Conference. E l s e v i e r S c i . Pub. Co. N.Y. Lindsay, W.L. 1979. Chemical E q u i l i b r i a Sons, Inc., New York. Loughnan, F.C. 1969. Chemical Elsevier.  i n Soils.  Weathering  John Wiley and  of S i l i c a t e  Minerals.  Lasaga, A.C. 1981. Rate laws o f chemical r e a c t i o n s , p. 1-68. In Eds. Lasaga, A.C. and K i r k p a t r i c k , R.J. K i n e t i c s o f Geochemical Processes. Reviews i n Mineralogy. V o l . 8. M i n e r a l o g i c a l S o c i e t y o f America, Washington, D.C. Loveland, P.J. and Digby, P. 1984. The e x t r a c t i o n o f Fe and A l by 0.1 M pyrophosphate s o l u t i o n s : a comparison o f some t e c h n i q u e s . J . o f S o i l S c i . 35: 243-250. Luce,  R.W., B a r t l e t t , R.W. and Parks, G.A. 1972. D i s s o l u t i o n k i n e t i c s o f magnesium s i l i c a t e s . Geochim. Cosmochim. A c t a 36: 35-50.  Luciuk, G.M. and Huang, P.M. 1974. E f f e c t o f m o n o s i l i c i c a c i d on h y d r o l y t i c r e a c t i o n s o f aluminum. S o i l S c i . Soc. Amer. Proc. 38: 235-244. McBride, M.B., Farmer, V . C , R u s s e l l , J.D., T a i t , J.M. and Goodman, B.A. 1984. Iron s u b s t i t u t i o n i n a l u m i n o s i l i c a t e s o l s s y n t h e s i z e d a t low pH. C l a y M i n e r a l s 19: 1-8.  132  McKeague, J.A. 1966. An e v a l u a t i o n o f 0.1 M pyrophosphate and pyrophosphate-dithionite i n comparison with oxalate as e x t r a c t a n t s o f the accumulation products i n podzols and some o t h e r s o i l s . Can. J . o f S o i l S c i . 47: 95-99. McKeague, J.A. and Day, J.H. 1965. D i t h i o n i t e - and o x a l a t e e x t r a c t a b l e Fe and A l as a i d s i n d i f f e r e n t i a t i n g v a r i o u s c l a s s e s o f s o i l s . Can. J . of S o i l S c i . 46: 13-22. McKeague, J.A., Brydon, J . E . and M i l e s , N.M. 1971. D i f f e r e n t i a t i o n of forms of e x t r a c t a b l e Fe and A l i n s o i l s . S o i l S c i . Soc. Proc. 35: 33-38. McKeague, J.A. and S c h u p p l i , P.A. 1985. An assessment of EDTA as an e x t r a c t a n t of organic-complexed and amorphous forms of Fe arid A l i n s o i l s . Geoderma 35: 109-118. . Manley, E.P. and Evans, L . J . D i s s o l u t i o n of f e l d s p a r s by low molecular - weight a l i p h a t i c and aromatic a c i d s . S o i l S c i . 141: 106-112. M a r t e l l , A.E. and Smith, R.M. 1982. C r i t i c a l S t a b i l i t y Constants. V o l . 3. Plenum Press, New York. Mehra, O.P. and Jackson, M.L. 1960. I r o n oxide removal from s o i l s and c l a y s by a d i t h i o n i t e - c i t r a t e system b u f f e r e d sodium b i c a r b o n a t e . C l a y s Clay Min. 7: 317-327.  with  Mortenson, J . L . 1963. Complexing of metals by s o i l o r g a n i c matter. S o i l S c i . Soc. Amer. Proc. 27: 179-186. N o r r i s h , K. and T a y l o r , R.M. 1961. The isomorphous replacement of i r o n by aluminum i n s o i l g o e t h i t e s . J . o f S o i l S c i . 52: 119123. N o r v e l l , W.A. 1972. E q u i l i b r i a of metal c h e l a t e s i n s o i l s o l u t i o n . In M i c r o n u t r i e n t s i n A g r i c u l t u r e . Ed. Mordtvedt. SSSA Inc. Madison, Wisconson, U.S.A. Olson, L.L. 1973. The i n t e r a c t i o n s o f F e ( I I I ) w i t h J . Inorg. N u c l . Chem. 35: 1977-1985.  Si(0H) . 4  Paces, T. 1973. Steady s t a t e k i n e t i c s and e q u i l i b r i u m between ground water and g r a n i t i c rock. Geochim. e t Cosmochim. Acta 37: 2641-2663. Paces, T. 1978. R e v e r s i b l e c o n t r o l o f aqueous aluminum and s i l i c a during i r r e v e r s i b l e e v o l u t i o n o f n a t u r a l waters. Geochim. e t Cosmochim. Acta.42: 1487-1493.  133  P a r f i t t , R.L., Farmer, V.C. and R u s s e l l , J.D. 1977a. A d s o r p t i o n on hydrous o x i d e s . I . Oxalate and benzoate on g o e t h i t e . J . S o i l S c i . 2 8 : 29-39. P a r f i t t , R.L. and C h i l d s , C.W. 1988. E s t i m a t i o n o f forms o f Fe and A l : A review, and a n a l y s i s o f c o n t r a s t i n g s o i l s by d i s s o l u t i o n and Moessbauer methods. Aust. J . S o i l Res.26: 121144. .r  P e t r o v i c , R. 1976. Rate c o n t r o l i n d i s s o l u t i o n o f a l k a l i f e l d s p a r s . I . Study o f r e s i d u a l f e l d s p a r g r a i n s by X - ray p h o t o e l e c t r o n spectroscopy. Geochim. Cosmochim. A c t a 40: 537548. I I . The p r o t e c t i v e e f f e c t o f p r e c i p i t a t e s . Geochim. Cosmochim. A c t a 40: 1509-1521. P o l z e r , W.L. and Hem, J.D. 1965. The d i s s o l u t i o n o f k a o l i n i t e . J . Geophys. Res. 70: 6233-6244. Oades, J.M. and Townsend, W.N. 1963. The detection of f e r r o m a g n e t i t e m i n e r a l s i n s o i l s and c l a y s . J . o f S o i l S c i . 14: 179-187. P a r f i t t , R.L. and C h i l d s , C.W. 1988. E s t i m a t i o n o f forms o f Fe and A l : A review and a n a l y s i s of contrasting soils by d i s s o l u t i o n and Moessbauer methods. Aust. J . S o i l Res. 26: 121-144. Pawluk, S. 1970. Measurement o f c r y s t a l l i n e and amorphous removal i n s o i l s . Can. J . S o i l S c i . 52: 119-123. Peech, M. 1965. Exchange a c i d i t y . In Methods o f S o i l P a r t 2. Ed. Black, C.A. Madison, Wisconson.  iron  Analyses.  P e t i t , J.C., D e l i a Mea, G., Dran, J.C., Schott, J . and Berner, R.A. 1987. D i o p s i d e d i s s o l u t i o n : new evidence from H-depth p r o f i l i n g w i t h a resonant n u c l e a r r e a c t i o n . Nature (London) 325: 705-707. Pohlman, A. and M c C o l l , J.G. 1988. S o l u b l e o r g a n i c s from f o r e s t l i t t e r and t h e i r r o l e i n metal d i s s o l u t i o n . S o i l S c i . Soc. Amer. Proc. 52: 265-271. P o r t e r , R.A. and Weber, W.A. 1971. The i n t e r a c t i o n o f s i l i c i c a c i d with i r o n ( I I I ) and u r a n y l i o n s i n d i l u t e aqueous s o l u t i o n . J . Inorg. Nucl. Chem. 33: 2443-2449. Rhoton, F.E., Bigham, J.M., Norton, L.D. and Smeck, N.E. 1981. C o n t r i b u t i o n o f magnetite t o o x a l a t e - e x t r a c t a b l e i r o n i n s o i l s and sediments from the Maumee R i v e r B a s i n o f Ohio. S o i l S c i . Soc. Amer. Proc. 45: 645-649.  134  S c h o t t , J . , Berner, R. and Sjoberg, E. 1981. Mechanism o f pyroxene and amphibole weathering - I. Experimental s t u d i e s of i r o n - f r e e m i n e r a l s . Geochim. Cosmochim. A c t a 45: 2123. S c o t t J . and Berner, R.A. 1983. X-ray p h o t o e l e c t r o n s t u d i e s o f the mechanism o f i r o n s i l i c a t e d i s s o l u t i o n d u r i n g weathering. Geochim. Cosmochim. A c t a 47:2333-2340. S c h a l s c h a , E.B., A p p e l t , H. and Schatz. A.1967. C h e l a t i o n as weathering mechanism. I . E f f e c t o f complexing agents on the solubilization of i r o n from m i n e r a l s and g r a n o d i o r i t e . Geochim. Cosmochim. A c t a 31:587-596. S c h n i t z e r , M. and Kodama, H. 1976. The d i s s o l u t i o n f u l v i c a c i d . Geoderma 15: 381-391.  o f micas  by  S c h o t t , J . and P e t i t , J . 1987. New evidence f o r the mechanisms of dissolution of s i l i c a t e minerals. In A q u a t i c Surface Chemistry. Ed. Stumm, W. John Wiley and Sons, New York. S c h u l t z , D.G. 1981. I d e n t i f i c a t i o n of s o i l i r o n oxide m i n e r a l s by d i f f e r e n t i a l X-ray d i f f r a c t i o n . S o i l S c i . Soc Amer. Proc. 45: 437-440. S c h u p p l i , P.A., Ross, G.A. and McKeague, J.A. 1983. The e f f e c t i v e removal o f suspended m a t e r i a l s from pyrophosphate e x t r a c t s o f s o i l s from t r o p i c a l and temperate r e g i o n s . S o i l S c i . Soc. Amer. Proc. 47: 1026-1032. Schwertmann, U. 1966. I n h i b i t o r y e f f e c t of s o i l o r g a n i c matter on the c r y s t a l l i z a t i o n of amorphous f e r r i c hydroxide. Nature (London). 212: 645-646. Schwertmann, U. 1971. T r a n s f o r m a t i o n of hematite s o i l s . Nature 232: 624-625.  to goethite i n  Schwertmann, U. 1973. Use o f o x a l a t e f o r Fe e x t r a c t i o n s o i l s . Can. J . S o i l S c i . 53: 244-246.  from  Schwertmann, U. 1985. Formation of secondary i r o n oxides i n v a r i o u s environments. In Ed. Drever, J . I . Nato ASI S e r i e s C. Vol.149. R e i d e l Pub. Co. H o l l a n d . Schwertmann, U. 1988. G o e t h i t e and hematite formation i n the presence o f c l a y m i n e r a l s and g i b b s i t e a t 25 C. S o i l S c i . Soc. Amer. Proc. 52: 288-291. Schwertmann, U. and T a y l o r , R.M. 1977. Iron oxides. M i n e r a l s i n S o i l Environments, pp. 145-176. S o i l S c i . Soc. of'America. Inc. Madison, U.S.  135  Schwertmann, U., Schulze, D.G. and Murad, E. 1982. Identification of f e r r i h y d r i t e in soils by dissolution kinetics, differential X-ray d i f f r a c t i o n , and Mossbauer s p e c t r o s c o p y . S o i l S c i . Soc. Amer. Proc. 46: 869-875. S i e v e r , R. and Woodford, N. 1979. D i s s o l u t i o n k i n e t i c s and the weathering o f mafic m a t e r i a l s . Geochim. e t Cosmochim Acta 43: 717-724. S i l l e n , L.G. and M a r t e l l , A.E. 1964. S t a b i l i i t y c o n s t a n t s of metal - i o n complexes. 2nd Ed. Spec. Pub. No. 17. The Chemical S o c i e t y , London. S i n g e r , A. and Navrot, J . 1976. E x t r a c t i o n o f metals from b a s a l t by humic a c i d s . Nature (London) 2 62: 479-481. S i n g l e t o n . G. 1978. Weathering i n a s o i l chronosequence. T h e s i s . Dept. of S o i l S c i e n c e . U.B.C.  PhD  S j o b e r g , S., I n g i i , N., Nenner, A. and Ohman,L. 1985. E q u i l i b r i u m and s t r u c t u r a l s t u d i e s o f s i l i c o n (IV) and aluminium (III) i n aqueous s o l u t i o n s . J . of Inorg. Biochem. 24: 267-277. Smith, B.F.L., Paterson, E. and Mitchell, B.D. 1982. T r i m e t h y l s i l y l a t i o n of commonly o c c u r i n g primary and secondary m i n e r a l s i n s o i l s . J . of S o i l S c i . 33: 115-124. S p o s i t o , G. Press.  1984.  Chemistry  of S o i l  S o l u t i o n s . Oxford  Stevenson, F . J . 1967. In Eds. McLaren, A.D. S o i l B i o c h e m i s t r y I . p. 119-146.  Clarendon  and Peterson,  Stevenson, F . J . Humus Chemistry. John Wiley and Sons. New Tamm, 0. 1922.  C i t e d i n Schwertmann and T a y l o r ,  G.H. York.  1977.  Van Schuylenborgh, J . 1964. From Experimental Pedology, pp.11312 5. Eds. Hallsworth, E.G. and Crawford, D.W. Butterworths,London. Veblen, D.R. and Buseck, P.R. Microstructures and reaction mechanisms i n b i o p y r i b o l e s . Amer. M i n e r a l . 65: 599-623. V i o l a n t e , A. and Huang, P.M. 1984. Nature and P r o p e r t i e s of pseudoboehmites formed i n the presence o f o r g a n i c and i n o r g a n i c l i g a n d s . S o i l S c i . Soc. Proc. 48: 1193-1201.  136  Wada, K. 1977. Allophane and i m o g o l i t e . p.603-638. In Eds.Dixon, J.B. and Weed, D.B. M i n e r a l s i n S o i l Environments. S o i l S c i . Soc. o f Amer. Madison, W.I. Walker, A.L. 1983. The e f f e c t s of magnetite on o x a l a t e - and d i t h i o n i t e - e x t r a c t a b l e i r o n . S o i l S c i . Soc. Amer. Proc. 47: 1022-1026. Wang, C., McKeague, J.A. and Kodama, H. 1986. Pedogenic i m o g o l i t e and s o i l environments: case study o f Spodosols i n Quebec, Canada. S o i l S c i . Soc. Amer. Proc. 50: 711-718. Weaver, R.M., Syers, J.K. and Jackson, M.L. 1968. Determination of s i l i c a i n c i t r a t e - b i c a r b o n a t e - d i t h i o n a t e e x t r a c t s o f s o i l s . S o i l S c i . Soc. Amer. Proc. 32: 497-501. Weber, W.J. and Summ, W. 1965. Formation of a s i l i c a t o i r o n ( I I I ) complex i n d i l u t e aqueous s o l u t i o n . J . I n o r g . Nucl. Chem. 27: 237-239. Weiss, A. and Herzog, A. 1978. P. 109-125. In Eds. Bendz, G. and L i n d q u i s t , I. B i o c h e m i s t r y of S i l i c o n and R e l a t e d Problems. Plenum, New York. Wilson, M.J., Jones, D. and McHardy, W.J. 1981. The weathering of s e r p e n t i n i t e by Lecanora a t r a . L i c h e n o l o g i s t 3: 167-176. W o l l a s t , R. 1967. K i n e t i c s of a l t e r a t i o n of K f e l d s p a r i n b u f f e r e d s o l u t i o n s a t low temperature. Geochim. Cosmochim. A c t a 31: 365. Yoldas, B.E. 1973. H y d r o l y s i s of aluminum a l k o x i d e s and b a y e r i t e c o n v e r s i o n . J . A p p l . Chem. Biotechnol.23: 803-809.  137  Appendix A ^  E x t r a c t a b l e Fe and A l from Weathered B a s a l t and Granodiorite  Extractable  Fe a n d Al  Basalt — Column — 4 Weeks  N  p X  X  U><Citric  Oxalic  Acetic  \//\ Pyro Fe  l\  R\W1  IXX1  Pyro Al  XI  HC1  HOH  Ox Fe  ^  Ox Al  g>553 CBD Al  CBD Fe  139 E x t r a c t a b l e " F e a n d Al Granodiorite — Column — 11 weeks  2.6 2.4 2.2 2 1.8 1.6 s x u  1.4 1.2 1 0.8 0.6 -  \ \  0.4 -  \  0.2 \2  0 Citric  Oxalic  Acetic  HCl  HOH  HCl  HOH  Treatment  E x t r a c t a b l e F e a n d Al Basalt — Column — 11 week  3  Citric  Oxalic  Acetic  Pyro Fe  rxXI  Ox Fe  CBD Fe  KS>s^l Pyro Al  [XX]  Ox Al  CBD Al  Extractable  Fe a n d Al  Basalt — Batch — 4 weeks  2.2 2 1.8 1.6  -  1.4  -  \ \ \ \ \ \  1.2 1 0.8 0.6 0.4  -  0.2  -  V;  0 Citric  r  Oxalic  HCl  Acetic  \ / XI  Pyro Fe  IXXl  Ox Fe  l^\>3  Pyro Al  CXX3  Ox Al  Y77Z\  HOH  CBD Fe CBD Al  141  E x t r a c t a b l e Fe a n d Al Granodiorite — Batch — 11 weeks  o a>  3a  o a u  X  w  0.2 0.1 Citric  Oxalic  Acetic  HC1  HOH  Treatment  E x t r a c t a b l e Fe a n d Al Basalt — Batch — 11 weeks  PI  4.5 -  / / / / / / / / / / / / / / / / / / /•  4 3.5 H 3  3  2.5 21.5 10.5  \ \ \ \  \ \ \ \ \ \  \ \  \2I  2 es_ HOH  0  Citric  Oxalic  KW\1  Acetic  HC1  Pyro Fe  l\M  Ox Fe  CBD Fe  Pyro Al  [XXI  Ox Al  C B D AI  Extractable 7  <.lmm  Fe a n d  B a s a l t B a t c h —11  Al  weeks  :  - r -  P y r o Al  IXXl  Ox A l  CBD Al  143 Extractable  Fe a n d  Al  Granodiorite Crusts— 11 weeks  V  3  Citric  HOH  Basalt Crusts-11 Weeks  2. s x  IX XI  Pyro Fe  KS^Xl  Pyro Al  CBD Al  144  Appendix A : 2  T a b l e s o f Data from E x t r a c t a b l e Fe and A l and S i from Weathered B a s a l t and G r a n o d i o r i t e  Extractable Iron. Aluminum and Silicon 1% by wt. I PARENT MATERIAL  PYROPHOSPHATE Fe  Granodiorite A Granodiorite B Basalt A Basalt B Hawaiin Basalt *A .lmm-.5mm *B:<. 1mm  Si  Al 0.00 0.00 0.00 0.00 0.00  OXALATE  0.00 0.00 0.00 0.00 0.00  Fe 0.00 0.00 0.00 0.00 0.00  DITHIONATE Al  Si 0.08 0.05 0.07 0.H 0.24  0.32 1.32 . 1.31 1.92 0.77  Fe 0.00 0.00 0.52 0.84 0.36  Al 0.28 1.38 0.18 0.61 0.25  Si 0.01 0.01 0.01 0.01 0.00  0.00 0.00 0.00 0.00 0.00  :  EXPERIMENT 1: COLUMN STUOY-4 WEEKS PYROPHOSPHATE Fe  Al  OXALATE Fe  PARENT MATERIAL  TREATMENT  GrDio. A GrDio. A GrDio. A GrDio. A GiDio. A  Citric Oxalic Acetic HCl HOH  0.13 0.03 0.04 .0.10 0.02  0.03 0.01 0.01 0.02 0.01  0.11 0.19 0.05 0.07 0.06  0.97 0.74 0.74 0.79 0.94  0.18 0.24 0.17 0.16 0.24  0.00 0.24 0.12 0.12 0.20  0.65 0.83 0.30 0.30 0.48  0.15 0.09 0.10 0.09 0.10  0.20 0.18 0.18 0.10 0.18  Basalt Basalt Basalt Basalt Basalt  Citric Oxalic Acetic HCl HOH  0.15 1.50 0.03 0.02 0.02  0.00 0.01 0.00 0.01 0.01  0.30 0.32 0.25 0.15 0.10  1.28 1.64 1.84 1.72 1.80  0.22 0.17 0.24 0.17 0.22  0.52 0.92 1.32 1.00 1.08  0.70 0.90 0.45 0.38 0.55  0.04 0.06 0.06 0.05 0.05  0.28 0.25 0.25 0.25 0.20  A A A A A  Si  OITHIONATE Al  Si  Fe  Al  Si  EXPERIMENT 2 BATCH STUDY-4 WEEKS  PARENT MATERIAL  TREATMENT  PYROPHOSPHATE Fe  Al  OXALATE Fe  Si  DITHIONATE Al  Si  Fe  Si  Al  GrDio. A GrDio A GrDio A GrDio A GrDio. A  Cilric Oxalic Acetic HCl HOH  0.06 0.52 0.09 0.01 0.01  0.01 0.01 0.01 0.01 0.00  0.26 0.24 0.06 0.00 0.00  0.72 0.90 0.72 1.05 1.00  0.13 0.12 0.09 0.12 0.19  0.00 0.00 0.00 0.00 0.24  0.18 0.45 0.30 0.40 0.48  0.04 0.06 0.06 0.06 0.09  0.10 0.13 0.10 0.13 0.10  Basalt Basalt Basalt Basalt Basalt  Citric Oxalic Acetic HCl HOH  0.15 0.88 0.05 0.01 0.01  0.01 0.01 0.01 0.01 0.01  0.54 0.25 0.07 0.16 0.26  1.60 1.60 0.91 2.20 1.80  0.12 0.08 0.14 0.17 0.10  0.72 0.60 0.00 0.92 0.76-  0.38 0.68 0.35 0.45 0.40  0.03 0.04 0.07 0.05 0.04  0.25 0.18 0.10 0.20 0.15  A A A A A  EXPERIMENT 3= COLUMN STUDY-11 WEEKS PARENT MATERIAL  TREATMENT  PYROPHOSPHATE Fe  Al  OXALATE Fe  DfTHIONATE Al  Si  Fe  Al  Si  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCI HOH  0.07 2.42 0.02 0.01 0.01  0.03 0.02 0.01 0.01 0.00  0.53 0.78 0.82 0.64 0.48  0.07 0.04 0.12 0.12 0.10  0.00 0.00 0.00 0.00 0.00  1.28 0.35 0.35 0.30 0.30  0.06 0.08 0.08 0.07 0.07  0.18 0.10 0.10 0.08 0.08  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCI HOH  0.12 6.50 0.45 0.01 ' 0.00  0.00 0.01 0.01 0.00 0.00  0.58 1.05 1.39 1.35 1.56  0.08 0.00 0.08 0.08 0.10  0.00 0.00 0.52 0.52 0.60  0.15 2.43 0.40 0.38 0.35  0.02 0.01 0.04 0.05 0.04  0.18 0.20 0.13 0.13 0.13  EXPERIMENT 4= BATCH STUDY-11 WEEKS PARENT MATERIAL  TREATMENT  PYROPHOSPHATE Fe  Al  OXALATE Fe  DfTHIONATE Al  Si  Fe  Al  Si  GrDio.A GrDio.A GrDio.A GrDio.A GrDio.A  Citric Oxalic Acetic HCI HOH  0.13 2.00 0.04 0.02 0.01  0.05 0.02 0.02 0.02 0.00  0.51 0.87 0.72 0.64 0.70  0.09 0.06 0.14 0.14 0.14  0.00 0.00 0.00 0.00 0.00  0.25 1.00 0.33 0.33 0.25  0.07 0.06 0.08 0.08 0.08  0.15 0.23 0.08 0.08 0.05  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCI HOH  0.20 4.70 0.02 0.01 0.00  0.00 0.00 0.01 0.01 0.00  0.66 0.68 1.60 1.10 1.60  0.09 0.00 0.09 0.06 0.10  0.12 0.00 0.68 0.44 0.68  0.19 0.25 0.35 0.35 0.38  0.02 0.05 0.03 0.04 0.04  0.20 0.20 0.13 0.10 0.13  Hawaiin Hawaiin  Citric Oxalic  0.32 3.00  0.01 0.01  1.09 0.88  0.23 0.06  0.16 0.00  0.60 1.43  0.06 0.03  0.25 0.20  EXPERIMENT 5= BATCH STUDY-11 WEEKS PARENT MATERIAL GfDio.B GrDio.B GfDio.B Basalt B Basalt B Basalt B  TREATMENT PYROPHOSPHATE Fe AL Citric Oxaic Acetic Citric Oxaic Acetic  0.95 5.10 0.11 0.19 ' 6.50 0.12  OXALATE Al Fe  Si  0.00 0.04 0.03 0.06 0.02 0.03  EXPERIMENT 6= BATCHII - WEEKS Analyses of Crust Formations PARENT MATERIAL TREATMENT PYROPHOSPHATE Fe GrDio.A GrDio.A GrDio.A GrDio.A GrDio.A Basalt A Basalt A Basalt A Basalt A Basalt A Hawaiin Ha wain GrDio.B GrDio.B GrDio.B Basalt B Basalt B Basalt B  Crtric Oxaic Acetic Ha HOH Citric Oxaic Acetic HCt HOH Citric Oxaic Citric Oxaic Acetic Citric Oxaic Acetic  2.60 19.00 0.16 0.26 0.28 0.90 25.00 0.25  Si 0.09 0.04 0.06 0.09 0.03 0.03  0.28 0.00 0.00 0.00 0.20 0.28  OXALATE Si  Al  1.30 1.64 1.40 1.09 1.40 1.60  0.89 0.43 0.07 0.24 0.62 0.08  DITHIONATE Fe Al  1.00 0.14 0.11 0.10 0.06 0.01 0.01 0.05  1.64 2.88 0.54 0.88 1.14 0.53 2.04 0.42  0.70 0.50 0.08 0.07 0.08 0.61 0.54 0.07  X  X  X  X  X  X  X  X  X  X  2.70 25.20 5.60 31.00 0.61  0.04 0.03  0.86 0.70  0.03 0.03 0.11  1.38 21.00 0.38  0.70 0.02 0.03  1.52 0.53 0.08 0.71 1.40 0.20  1.16 2.04 1.48 2.52 8.20 0.92 3.20 2.08  0.03 0.05 0.05 0.09 0.02 0.02  0.58 2.63 2.63  0.25 0.23 0.08 0.18 0.23 0.20  DITHIONATE Al  Fe  0.58 3.38 1.15  Si  Si 0.62 0.33 0.20 0.31 0.46 0.06 0.00 0.25 0.10 0.00 0.05 0.07 0.42 0.44 0.00 0.24  Fe 0.00 0.12 0.00 0.20 0.32 0.16 0.24 0.80  Si  Al 0.70 0.42 0.14 1.80 1.38 0.02 0.01 0.04  1.23 8.30 0.83 0.99 0.72 0.53 5.53 0.43  X  X  X  X  X  X  X  X  0.24 0.24  1.03 4.10  0.28 0.00 0.60 0.16 0.12 1.12  0.28 0.25 0.15 0.19 0.21 0.25 0.33 0.13  2.08 11.55 0.88  0.08 0.05 0.04 0.09 0.05  0.30 0.43 0.45 0.25 0.08  0.90 2.53 0.85  0.48 0.02 0.07  0.23 0.28 0.13  148  Appendix B:  S o l u t i o n A n a l y s e s o f 5 L e a c h i n g Treatments G r a n o d i o r i t e and B a s a l t Column Study *Data i s average o f 3 r e p l i c a t e  samples  149 GRANODIORITE CALCIUM  2  0. a.  u z o o z o  p  3 o  WEEK  9  H20  CITRIC  BASALT CALCIUM 120  - i  W  •  CITRIC  WEEK  E  —  E  K  1  WEEK 3  +  OXALIC  WEEK 5  O  WEEK 7  ACETIC  WEEK  *  HCL  9  11  1 5 1 BASALT SODIUM  11 -,  BASALT SODIUM  WEEK 1 •  CITRIC  WEEK 3 +  OXALIC  WEEK 5 o  WEEK 7 ACETIC  WEEK 9 A  HCL  •  CITRIC  +  OXALIC  o  ACETIC  A  HCL  x  H20  154 GRANODIORITE  ALUMINIUM  400 350 H 300 H s  a. a.  xj  z o  C_>  Z  o •3 c 7}  250 200 -\ 150 H 100 50 H WEEK 1  * WEEK 3 OXALIC  • CITRIC  * * W E EK 7 WEEK 5 o ACETIC  WEEK 9 A HCL  WEEK 1 1 x 1120  BASALT  ALUMINIUM  60 50 c c  40 H  <J  z o u  30 H  O C/3  20 H  z o  10  - i  WEEK 1 D CITRIC  WEEK 1 1 H20  155 GRANODIORITE 450  SILICON - i  WEEK 1 O  CITRIC  '  WEEK 3 +  OXALIC  WEEK 5 o  WEEK 7 ACETIC  WEEK 9 A  HCL  WEEK x  H20  11  156  Appendix C:  S o l u t i o n A n a l y s e s o f 5 L e a c h i n g Treatments G r a n o d i o r i t e and B a s a l t Batch Study *Data i s average o f 3 r e p l i c a t e  samples  157 GRANODIORITE CALCIUM  s a. a. o Z O  u z o  3o  in  WEEK 1 •  CITRIC  WEEK 3 OXALIC  WEEK 5 ©  WEEK 7 ACETIC  WEEK 9 A  HCL  WEEK 1 1 H20  BASALT CALCIUM  a. a. o z o o z o  •3 o to  WEEK 11 CITRIC  H20  158 GRANODIORITE MAGNESIUM  50  -  40  -  30  -  20  -  WEEK O  CITRIC  1  WEEK 3 +  OXALIC  WEEK 5 o  WEEK 7 ACETIC  WEEK 9 A  HCL  WEEK >:  11 H30  159 GRANODIORITE SODIUM  3 OL  0. U  z o .o z o D ' O  WEEK  CITRIC  1  WEEK  3  OXALIC  WEEK 5  O  WEEK  ACETIC  BASALT SODIUM  7  WEEK HCL  9  WEEK  11  H20  160 GRANODIORITE 280  -|  :  POTASSIUM ~~  BASALT POTASSIUM  BASALT IRON 2.B  - j -  162 GRANODIORITE ALUMINIUM  350 300 s a.  250  c o z o  200 H  o  150  v z  p  D _l  o 1/5  100 -\  WEEK  • CITRIC  +  OXALIC  o  ACETIC  BASALT ALUMINIUM  a. c u z o z o  p  -OJ t/3  n  CITRIC  A  HCL  WEEK  9 >:  11  1120  163 GRANODIORITE SILICON  WEEK 11 H20  BASALT SILICON 1.4 1.3  U  z © o Z  o  1.1  -*  0.9 (fi  T3,  c a »• o  H 3  -  1 -  2 0. ^  1.2  -  O.B 0.7 0.6 0.5  -  0.4 ~ 0.3  -  0.2  -  0.1  -  0 -1 WEEK 1 CITRIC  WEEK 3 OXALIC  WEEK 5 o  WEEK 9  WEEK 7 ACETIC  &  HCL  WEEK 11 H20  164  Appendix D:  S o l u t i o n A n a l y s e s o f 5 L e a c h i n g Treatments G r a n o d i o r i t e "B" and B a s a l t "B" Batch Study *Data i s average o f 2 r e p l i c a t e  samples  •  C IT R IC  +  OXALIC  o  ACETIC  1 6 6 <,1mrn  GRANODIORITE MAGNESIUM  2.4  a 0- ^ CO CJ T>  w  z c o « w 3 2  2  3 J O 7)  WEEK  1  WEEK3  WEEK  CITRIC  5  WEEK  7  WEEK  OXAUC  <, 1 m m  9  WEEK  11  WEEK  11  ACETIC  BASALT  MAGNESIUM 160  - i  WEEK  1  WEEK3  •  CITRIC  WEEK 5  +  OXALIC  WEEK 7  WEEK 9  o  ACETIC  167 <.1 m m  GRANODIORITE SODIUM  80  WEEK  1  WEEK 3  •  CITRIC  WEEK 5  +  WEEK 7  OXALIC  <.1mm  WEEK 9  o  WEEK  11  ACETIC  BASALT  SODIUM 55  -|  o  H  WEEK  1 1  WEEK 3  •  CITRIC  1 WEEK 5 .  OXALIC  1  1  WEEK 7  WEEK 9  o  ACETIC  1 WEEK  11  168 <.1 m m  GRANODIORITE POTASSIUM  WEEK  1  WEEK 3  WEEK 5  WEEK 7  WEEK 9  •  CITRIC  +  OXALIC  o  ACETIC  •  CITRIC  +  OXALIC  o  ACETIC  WEEK  11  CITRIC  +  OXALIC  ACETIC  170 <.1 m m 400  GRANODIORITE ALUMINIUM  -i  —  WEEK 1  WEEK 3  WEEK 5  WEEK 7  WEEK 9  n  CITRIC  +  OXALIC  o  ACETIC  •  CITRIC  +  OXALIC  o  ACETIC  WEEK 11  1 7 1 <.1mm  GRANODIORITE SILICON  WEEK  1  WEEK 3  •  CITRIC  WEEK 5  +  WEEK 7  OXALIC  <. 1 m m  WEEK 9  o  WEEK  11  WEEK  11  ACETIC  BASALT  SILICON 900  S  Pu OH  O  z o t_> z o  3 O'  t/1  WEEK  1  WEEK  CITRIC  3  WEEK  5  OXALIC  WEEK  7  WEEK  ACETIC  9  172  A n a l y s e s o f S o l u t i o n pH from 5 L e a c h i n g Treatments G r a n o d i o r i t e and Basalt-Column and Batch S t u d i e s *Data i s average o f 3 r e p l i c a t e  samples  1 7 3 Solution  pH — 4  Batch  6  Weeks  — Granodiorite  7  6  5  <>  —  •  —  -  -  "  "  ~~  ——• " "  3 c  '  ~  ~  2  —  WEEK 1  +  —  j  Oxalic  pH— 4  Batch -i  ,  Acetic  o  Solution 7.5  Q  1  -  A  .  £]  —  HCI  x  HOH  Weeks  Basalt —  WEEK 1  Citric  +  Oxalic  ©  Acetic  A  HCI  x  HOH  174 Solution Colomn  g  pH  — Granodiorite  Citric  Solution Column  1  Citric  ~l  3  pH  — Basalt  Acetic  Oxalic  Citric  Solution Batch  WEEK  Citric  1  WEEK 3  +  Oxalic  pH  — Basalt  WEEK 5  o  HOH  HCl  WEEK 7  Acetic  WEEK 9  A  HCl  WEEK  x  11  HOH  176  Appendix F:  T a b l e o f Data from S o l u t i o n A n a l y s e s o f 5 L e a c h i n g Treatments G r a n o d i o r i t e and B a s a l t - Column and Batch 1 Month Study  COLUMN STUDY- 4 WEEK WEATHERING EXPERIMENT ANALYSES OF SOLUTION EXTRACTS Ippm I PARENT MATERIAL TREATMENT  Ca  Mg  Na  K  Fe  Al  GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE  CITRIC CITRIC CITRIC OXALIC OXALIC OXALIC ACETIC ACETIC ACETIC HCI HCI HCI HOH HOH HOH  195.0 206.0 143.0 49.5 40 0 410 68.5 65.5 67.0 89 0 100.0 114 0 10.8 5,0 8.2  106 0 1250 84.0 159 0 149 0 163.0 4 7 4.4 5.4 68.0 44 0 54 0 09 04 0.8  17.2 17.0 16.9 9.7 18 9 19 3 93 8.6 8.8 18.4 14.9 12.8 4.7 6.5 4.1  74.0 85.0 61.0 192 0 162 0 195 0 23.0 27.2 25.5 62 0 52.0 54 5 6.5  860.0 480.0 430.0 310 0 230.0 3100 250.0 130.0 280 0 360.0 370.0 220.0 00  51 5.6  0.0  BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT  CITRIC CITRIC CITRIC OXALIC OXALIC OXALIC ACETIC ACETIC ACETIC HCI HCI HCI HOH HOH HOH  109.0 75.0 102 0 26.5 26.5 35 3 34 0 56.0 46 0 65 0 48 0 57 0 0.8 0 9 16  1180 0 11200 1550 0 200 0 207.0 ?06 0 10 0 12 6 19.4 375 0 3350 204.0 00 00 00  8.3 11.0 10 9 10.3 10 4 10 3 5.8 9.9 10.1 12.9 16.6 14:7  1.8 2.4 28 1.0 1.2 1.4 2 3 3.2 3 6 2 9 5.1 5.0 12 0 8 0 8  2310 0 2100 0 34000 370.0 3200 350 0 . 620 85 0 97 0 520 0 630 0 430.0 00 00 .0 0  4.2 29 3.3  0.0  Si 209.0 234.0 216.0 312.0 375 0 370.0 16.0 13.0 12.0 147.0 115.0 112 0 0.0 0.0 0.0 20.0 20.0 30 0 44 0 41 0 44 0 12 0 11.0 13 0 31.0 34.0 35.0 0 0 00 0.0  170.0 190.0 190 0 340:0 340 0 350.0 40.0 300 30.0 140.0 130.0 110 0 0.0 00 0.0 100.0 80.0 950 59 0 61.0 59 0 40 0 30 0 50.0 54.0 58.0 62 0 0.0 00 00  BATCH STUDY- 4 WEEK WEATHERING EXPERIMENT ANALYSES OF SOLUTION EXTRACTS Ippm I PARENT MATERIAL TREATMENT  Ca  Mg  GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE  CITRIC CITRIC CITRIC OXALIC OXALIC OXALIC ACETIC ACETIC ACETIC HCl HCl HCl HOH HOH HOH  214.0 192.0 201.0 42.0 34.0 39.5 62 0 510 62.9 120.0 143.0 134.0 7 4 7.8 2.0  142.0 145.0 129.0 193 0 . 187.0 184 0 17.0 12.0 1 7.0 70.0 75.0 85 0 6.8 6 2 6.9  BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT BASALT  CITRIC CITRIC CITRIC OXALIC OXALIC OXALIC ACETIC ACETIC ACETIC HCl HCl HCl HOH HOH  110 0 130.0 120.0 30 0 28 0 29.0 55 0 86.0 75.0 16 4 15.0 18 3  BASALT  HOH  999.0 1090.0 1020.0 110.0 120.0 158.0 16.0 21.0 23.0 300.0 320.0 326.0 20 2.5 2.1  5.5  5.2 6.2  Na  K 33.5 27.7 34.0 33.2 28 5 33.0 17 5 14 6 19.5 19 0 21.0 24.0 10.3 10.3 10.7 25.6 24 0 28.0 22.3 23.0 22.5 . 17.5 19.0 21.0 11.6 1 1.8 11.2 13.2 10 5 11.6  Fe 90.0 92.0 940 155.0 145.0 123.0 50.0 45.0 52.0 64.0 52.0 56.0' 14.2 . 14.2 15.0 70 8.0 7.8 2.0 1.8 2.5 47.0 .61.0 58.0 3.7 2.9 2 2 1.0 1.3 1.7  Al 930.0 990.0 780.0 147.0 142.0 181.0 . 310.0 290.0 278.0 310.0 325.0 340.0 0.0 0.0 0.0  2710.0 2432.0 2980 0 420.0 452.0 480.0 220.0 210 0 198.0 410.0 390.0 345.0 0.0 0.0 0.0  Si 345.0 278.0 359.0 368.0 315.0 379:0 45.0 32.0 38.0 125.0 132.0 128.0 0.0 0.0 0.0  270.0 240.0 290.0 325.0 350.0 362.0 70.0 40.0 50.0 125.0 134.0 137 0 0.0 0.0 00  65.0 49.0 58.0 54.0 52.0 57.0 16.0 28.0 24.0 35.0 36.0 34.0 0.0 0.0 2.0  89 0 110.0 98.0 70.0 50.0 54.0 45.0 42.0 42.0 48.0 56.0 57.0 0.0 0.0 0.0  179  Appendix G:  T a b l e s o f Data from S o l u t i o n A n a l y s e s o f 5 L e a c h i n g Treatments G r a n o d i o r i t e and B a s a l t - Column and Batch 11 Week Study *Data i s average o f 3 r e p l i c a t e  samples  COLUMN STUDY SOLUTION EXTRACTS CALCIUM  Ippm)  WEEK 1  WEEK 3  WEEKS  WEEK 7  WEEK 9  WEEK 11  MAGNESIUM WEEK 1  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK II  GRANITE  CITRIC OXALIC ACETIC HCL H20  188.33 43.83 45.17 74.00 4.23  103.00 50.30 37.33 48.83 5.53  29.00 32.70 33.73 34.60 2.80  16.17 21.50 •33.47 31.00 1.70  12.03 15.33 22.50 26.83 1.17  9.33 9.67 23.33 25.33 0.00  41.73 94.67 32.33 56.00 0.40  70.33 159.00 3.07 6.27 0.40  53.33 158.67 3.60 6.57 0.00  54.00 113.33 4.47 6.53 0.00  48.00 104.33 4.30 8.13 0.00  30.67 47.67 4.70 9.17 ' 0.00  BASALT  CITRIC OXALIC ACETIC HCL H20  113.67 36.00 35.83 42.01 0.00  94.33 25.33 23.00 33.00 0.00  43.67 13.50 17.23 14.50 0.90  32.67 11.00 11.63 4.43 0.40  29.77 3.53 13.17 23.00 0.43  14.00 5.00 9.67 15.00 0.00  637.67 204.33 7.53 9.67 0.00  1443.33 296.67 13.40 16.37 0.00  1223.33 536.67 17.00 14.07 0.00  573.33 336.67 17.67 9.47 0.00  430.00 131.33 21.50 20.47 0.00  176.33 100.67 17.37 18.60 0.00  WEEK 1  WEEK 3  WEEK 5 , WEEK 7  WEEK 9  WEEK 1  WEEK 3  WEEK 5  WEEK 7  WEEK 9  SODIUM  WEEK 11  POTASSIUM  WEEK II  GRANITE  CITRIC OXALIC ACETIC HCL H20  12.63 16.17 5.67 6.23 2.70  4.87 8.97 2.83 3.03 1.37  2.70 6.47 1.60 2.07 0.80  2.57 5.17 1.20 1.03 0.60  2.07 4.37 0.47 0.77 0.20  1.93 3.53 0.57 0.67 0.07  40.17 124.67 14.70 18.83 3.33  62.87 228.67 15.20 19.93 3.63  48.80 222.67 11.00 13.57 3.07  49.57 146.00 8.37 9.33 2.30  56.00 132.00 5.47 8.43 1.23  48.37 81.50 5.27 7.50 0.33  BASALT  CITRIC OXALIC ACETIC HCL H20  10.10 10.60 6.07 6.30 1.83  3.67 5.97 2.60 3.40 0.67  3.27 5.80 2.00 2.30 0.60  2.67 3.60 1.30 1.10 0.13  1.53 4.43 1.23 2.67 0.00  0.83 4.67 1.07 2.67 0.00  3.17 1.00 2.73 1.90 0.00  1.07 0.67 1.27 1.30 0.00  1.67 0.70 1.33 1.07 0.00  1.57 1.77 0.83 0.50 0.00  0.50 0.87 0.20 0.40 0.00  0.43 0.20 0.27 0.00 0.00  o  IRON  WEEK 1  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK II  ALUMINIUM  WEEK 1  WEEK 3  WEEKS  WEEK 7  WEEK 9  WEEK II  GRANITE  CITRIC OXALIC ACETIC HCL H20  346.67 596.67 41.00 39.67 4.00  206.67 713.33 23.33 35.67 0.00  117.67 653.33 12.33 21.00 0.00  143.33 406.67 14.00 19.00 0.00  100.00 260.00 11.33 20.00 0.00  109.67 141.33 9.33 19.33 0.00  130.33 258.67 14.33 9.00 3.67  111.33 363.00 11.33 14.67 0.00  73.33 280.00 12.00 17.67 0.00  79.00 222.67 10.00 11.67 0.00  81.00 193.33 13.33 13.00 0.00  65.33 131.00 5.67 12.67 0.00  BASALT  CITRIC OXALIC ACETIC HCL H20  1813.33 426.67 26.33 33.00 3.67  2533.33 656.67 44.00 69.33 0.00  1533.33 613.33 56.67 54.00 0.00  1533.33 613.33 56.67 54.00 0.00  653.33 113.00 55.33 54.33 0.00  243.33 64.00 44.33 44.33 0.00  43.33 55.00 11.00 7.33 5.00  14.67 35.33 8.33 5.00 0.00  6.33 28.67 9.67 5.67 000  7.00 23.00 8.00 5.33 0.00  7.67 22.33 7.67 0.73 0.00  3.33 24.33 3.67 11.33 0.00  WEEK I  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK 11  CITRIC OXALIC ACETIC HCL H20  120.00 263.33 21.67 13.33 0.00  126.67 410.00 0.00 0.00 0.00  80.00 340.00 0.00 0.00 0.00  93.33 250.00 0.00 0.00 0.00  133.33 243.33 0.00 0.00 0.00  106.67 160.00 0.00 0.00 0.00  CITRIC OXALIC ACETIC HCL H20  1253.33 510.00 10.00 20.00 0.00  1366.67 853.33 20.00 30.00 0.00  1016.67 1 106.00 20.00 6.67 0.00  673.33 803.33 10.00 0.00 0.00  486.67 1020.00 43.33 20.00 0.00  176.67 683.33 23.33 26.70 0,00  SILICON GRANITE  BASALT  H 03 H  BATCH STUDY SOLUTION EXTRACTS (ppm) CALCIUM  WEEK 1  WEEK 3  WEEK 5  GRANITE  CITRIC OXALIC ACETIC HCL HOH  26.03 45.83 48.17 25.67 4.23  183.33 44.67 29.67 30.00 4.17  BASALT  CITRIC OXALIC ACETIC HCL HOH  80.50 10.53 29.67 42.20 1.43  • 58.33 9.83 13.33 28.17 1.90  CITRIC OXALIC ACETIC HCL' H20  WEEK 1 13.33 17.90 6.50 3.87 3.07  WEEK 3 9.50 10.50 4.90 4.03 2.67  WEEK 5 6.80 7.57 2.60 2.70 1.47  CITRIC OXALIC ACETIC HCL H20  10.57 11.00 8.20 8.80 2.43  5.60 7.07 4.10 5.63 2.90  4.00 5.20 3.73 4.43 1.63  SODIUM GRANITE  BASALT  215.00 56.00 18.17 17.17 3.73 49.03 1 1.83 11.83 18.83 1.33  WEEK 7  WEEK 9  WEEK 11  MAGNESIUM WEEK I  WEEK 3  WEEK 5  64.67 43.90 16.47 14.00 2.03  39.33 38.17 12.17 • 6.43 3.73  19.26 33.83 12.17 5.47 4.17  58.33 157.67 6.33 •4.83 2.27  96.67 133.33 6.57 11.60 3.47  47.93 28.50 12.07. 17.17 1.57  38.33 11.40 10.07 7.73 1.53  34.50 23.83 12.50 10.33 1.13  936.67 191.00 7.17 10.00 0.37  746.67 38.87 3.60 9.23 0.00  WEEK 7 5.70 8.50 2.67 1.83 1.97  WEEK 9 5.07 7.67 1.60 1.07 0.67  WEEK 11 4.40 7.30 1.30 1.17 0.83  POTASSIUM WEEK I 46.33 146.00 24.17 12.90 7.07  WEEK 3 81.00 178.33 24.00 21.50 8.83  WEEK 5 133.67 268.00 20.97 19.97 7.20  4.27 4.73' .4.40 4.70 1,60  3.10 3.53 3.50 2.37 1.07  2.77 4.10 3.40 3.17 0.90  3.33 1.77 4.00 3.03 0.53  1.17 0.83 1.17 1.67 0.00  1.47 1.13 1.43 2.00 0.77  145.33 189.00 7.97 9.00 2.83 1190.00 140.67 4.40 9.23 0.00  WEEK 7  WEEK 9  WEEK 11  116.00 175.33 12.67 10.83 2.37  97.33 155.33 9.43 8.03 2.77  93.67 1 14.33 9.13 9.37 4.60  1300.00 143.00 7.37 1 1.23 0.00  836.67 111.67 7.27 5.30 0.40  756.67 139.33 9.77 8.60 0.00  WEEK 7 86.33 239.33 26.03 •21.20 6.07  WEEK 9 95.67 196.33 19.93 12.97 5.50  WEEK 11 83.67 174.67 15.53 14.37 6.87  1.53 1.10 1.60 1.87 1.13  1.13 0.77 1.00 0.83 0.63  0.40 0.20 0.00 0.00 0.40  IRON GRANITE  BASALT  SILICON GRANITE  BASALT  CITRIC OXALIC ACETIC HCL H20  WEEK 1 616.67 683.33 203.00 31.33 14.33  CITRIC OXALIC ACETIC HCL H20  2346.67 296.67 • 36.67 65.33 14.67  CITRIC OXALIC ACETIC HCL H20  WEEK 1 140.00 323.33 33.33 0.00 16.67  CITRIC OXALIC ACETIC HCL H20  1113.33 693.33 26.67 33.33 23.33  WEEK 3 336.67 600.00 88.67 84.33 28.00  WEEK 5 373.33 860.00 58.67 71.00 13.33  WEEK 7 256.67 740.00 63.33 54.33 0.00  WEEK 9 270.00 680.00 48.00 34.33 • 9.33  2666.67 306.67 17.67 36.00 2.67  1666.67 263.33 20.00 19.00 0.00  1200.00 193.33 21.67 13.33 4.67  1 113.33 246.67 19.67 1 1.67 1.00  WEEK 3 196.70 373.30 50.00 23.30 23.30  WEEK 5 203.30 350.00 13.30 0.00 0.00  WEEK 7 206.00 380.00 30.00 20.00 0.00  WEEK 9 190.00 370.00 26.70 6.70 0.00  WEEK 1 1 196.67 336.67 30.00 13.33 0.00  1080.00 643.00 30.00 36.70 20.00  1323.30 763.30 46.67 43.30 3.33  1346.00 820.00 40.00 33.00 0.00  1016.00 753.00 30.00 0.00 0.00  1996.67 . 173.33 14.00 50.67 8.67  WEEK 11 233.53 525.33 37.00 36.67 28.67  903.33 760.00 40.00 26.00 0.00  WEEK 1 149.33 325.00 12.00 0.00 5.00  WEEK 3 169.00 335.33 21.67 2.67 9.67  42.33 53.67 12.33 4.67 6.67  20.00 30.67 18.35 22.00 9.33  WEEK 5 162.35 290.00 18.00 9.55 5.67 15.00 20.55 . 19.55 ' 25.00 5.55  WEEK 7 WEEK 9 140.67 154.67 558.67 . 326.67 26.00 25.00 10.67 10.35 0.00 6.35 15.00 18.67 19.55 17.33 0 00  15.00 21.00 21.53 15.00 7.35  WEEK II 142.55 518.55 18.55 12.55 1 1.00 12.00 19.67 18.00 17.35 0.00  00 U)  BATCH SOLUTION EXTRACTS I p p m ) Particles <» 1 mm  CALCIUM  GRANITE BASALT  WEEK I  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK I I  CITRIC OXALIC ACETIC  330.00 8.00 50.00  75.00 24.75 46.25  60.20 33.50 53.00  37.13 28.25 30.50  48.50 23.20 22.25  39.00 19.00 21.00  CITRIC OXALIC ACETIC  275.00 8.10 31.20  96.00 6.00 18.00  141.00 9.75 17.00  135.00 10.00 16.25  115.00 6.70 14.50  1 14.00 7.75 17.00  MAGNESIUM WEEK I  GRANITE BASALT  WEEK 3  WEEK 5  WEEK 7  WEEK 9  CITRIC OXALIC ACETIC  2260.00 9.80 10.90  1315.00 64.00 8.70  1260.00 136.00 8.20  735.00 97.50 6.10  975.00 69.50 3.55  CITRIC OXALIC ACETIC  69.00 18.00 15.20  92.00 21.95 4.30  70.00 154.00 16.50  63.50 130.00 2.75  61.00 1 13.00 2.40  WEEK 11 635.00 51.50 "4.15 85.00 82.50 2.85 H  CO SODIUM  WEEK I  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK 11  POTASSIUM  WEEK I  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK 11  GRANITE  CITRIC OXALIC ACETIC  77.50 ' 23.50 18.50  15.35 16.55 15.25  8.65 17.70 11.80  4.55 10.80 5.45  3.90 8.50 3.65  2.75 7.25 3.50  GRANITE  CITRIC OXALIC ACETIC  13.90 29.75 43.75  3.85 89.50 58.50  2.65 240.00 50.00  0.45 145.00 18.45  0.80 110.00 13.00  0.80 72.50 12.50  BASALT  CITRIC OXALIC ACETIC  50.50 33.25 12.75  14.45 23.50 10.00  9.60 24.80 14.50  6.20 13.10 7.85  3.75 5.25 5.55  5.10 3.20 5.70  BASALT  CITRIC OXALIC ACETIC  169.00 3.75 3.00  52.45 2.75 2.50  54.50 3.10 3.85  59.75 2.10 2.35  50.70 1.20 1.55  73.50 0.55 0.35  IRON GRANITE  BASALT  BASALT  WEEK 3  WEEK 5  WEEK 7  WEEK 9  ALUMINIUM  WEEK 11  WEEK I  WEEK 3  9150.00  1030.00  2250.00  1250 0 0  1300.00  1325.00  CITRIC  230.00  50.00  OXALIC  7.50  57.00  280.00  250.00  200.00  170.00  OXALIC  380.00  248.00  ACETIC  1650.00  660.00  615.00  190.00  105.00  120.00  ACETIC  CITRIC  CITRIC •  GRANITE  0.00  8.50  WEEK 5 '  28.00 355.00 31.00  WEEK 7 15.50  WEEK 9 4.50  WEEK II 6.50  264.00  199.50  215.00  30.00  24.00  21.00  13400.00  9300 0 0  390 00  200.00  110.00  200 00  CITRIC  198.00  197.00  151.00  136.00  96.50  "111.50  OXALIC  12.50  39.00  260.00  175.00  175.00  150.00  OXALIC  88.00  97.00  110.00  64.00  27.00  14.00  ACETIC  790.00 ;  155.00  205.00  76.00  34 0 0  20.00  ACETIC  24.00  39.00  27.00  27.50  25.50  SILICON . GRANITE  WEEK I  CITRIC  WEEK I  WEEK 3  WEEK 5  WEEK 7  WEEK 9  WEEK 11  1485.00  720.00  525.00  535.00  610.00  590.00  OXALIC  115.00  230.00  375.00  230.00  160.00  155.00  • ACETIC  0.00  20.00  65.00  20.00  20.00  20.00  CITRIC  230.00  135.00  120.00  135.00  95.00  120.00  OXALIC  475.00  815.00  880.00  815.00  570.00  550.00  ACETIC  2500  30.00  25.00  25.00  0.00.  0.00  BASALT  0.00  186  T a b l e s o f Data from pH A n a l y s e s o f Weathered G r a n o d i o r i t e and B a s a l t i c Residues and S o l u t i o n Extracts *Data i s average o f 3 r e p l i c a t e samples  pH OF UNWEATHERED AND WEATHERED RESIDUES  PARENT MATERIALS Granodiorite A Granodiorite B Basalt A Basalt B  HOH  CaCI (.OIM)  7.10 7.30 6.60 7.00  6.55 5.70 5.00 5.83  *A:.1 m m - . 5 m m *8:<.1mm  EXPERIMENT 1: COLUMN STUDY-4 WEEKS  EXPERIMENT 3= COLUMN STUDY-11 WEEKS CaCI 1.0 IMI  PARENT MATERIAL  TREATMENT  HOH  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  3.08 5.20 4.83 2.93 5.49  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  5.84 6.30 4.60 3.07 4.92  PARENT MATERIAL  TREATMENT  HOH  CaCI 1.0 IM)  2.99 4.20 4.82 3.16 5.80  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  2.94 4.50 4.53 4.00 5.40  2.73 3.56 4.06 3.60 5.82  5.70 4.40 4.18 3.34 5.47  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  4.25 4.81 4.83 4.23 5.26  3.48 4.17 4.61 3.96 5.08  EXPERIMENT 4= BATCH-11 WEEKS  EXPERIMENT 2= BATCH STUDY-4 WEEKS  PARENT MATERIAL  TREATMENT  3.18 4.40 4.40 6.09 6.40  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  2.82 4.32 4.49 3.80 5.35  2.88 3.84 4.36 4.26 6.10  5.80 5.35 4.30 5.02 5.72  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  5.57 5.13 4.51 3.50 5.50  5.50.  CaCII.OlM)  PARENT MATERIAL  TREATMENT  HOH  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  3.35 5.00 4.45 6.1 1 6.65  Basolt Bosalt Basolt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  5.84 6.20 4.51 5.40 5.53  HOH  CaCI (.OIM)  4.42  4.15 3.95 5.80  00 -0  188 BATCH and COLUMN STUDY- 4 WEEK WEATHERING EXPERIMENT PH ANALYSES OF SOLUTION EXTRACTS (Average of 3 replicates I COLUMN  TREATMENT TIME 0  GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE  CITRIC OXALIC ACETIC HCl HOH  2.2 1.6 2.9 2.3 5.8  BASALT BASALT BASALT BASALT BASALT  CITRIC OXALIC ACETIC HCl HOH  2.2  BATCH  TREATMENT TIME 0  GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE GRANODIORITE  CITRIC OXALIC ACETIC HCl HOH  BASALT BASALT BASALT BASALT BASALT  CITRIC OXALIC ACETIC HCl HOH  1.6  2.9 2.3 5.8  2.2 1.6  2.9 2.3 5.8 2.2 1.6  2.9 2.3 5.8  WEEK 1 2.3 1.9  3.1 2.3 6.0 4.1 4.5 3.5 2.3 6.7  WEEK 1  WEEK 3  WEEK 4  2.3 2.8 3.8 2.4 7.1  2.3 4.4 3.8 2.4 7.2  5:2 5.5 3.5  6.4 •6.7 3.5 3.2 6.8  3.0-  6.7  WEEK 3  WEEK 4  2.5 2.7 3.8 2.4 6.8  2.5 3.4 4.0 2.5 7.0  2.6 4.4 4.1 2.5 7.2  4.0 5.0 3.5 2.3 6.6  4.1 5.3 3.9 2.4 6.7  4.1 6.6 4.0 2.6 7.0  189  pH OF SOLUTON EXTRAC TS COLUMN EXPERIMENT - 11 WEEKS PARENT MATERIAL  TREATMENT TIME 0  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  Citric Oxolic Acetic HCL HOH  2.2 1.6 2.9 2.3 5.8  Citric Oxalic Acetic HCL HOH  2.2 1.6 2.9 2.3 5.8  A A A A A  Basalt A Basalt A Basalt A Basalt A 8asalt A  WEEK 1  WEEK 3  WEEK 5  2.2  2.4 1.5 3.2 3.0 6.9  2.3 1.5 3.0 3.0 6.3'  1.4  1.4  3.4 3.7 6.7  2.3 1.6 3.2 3.2 •7.3  2.9 2.9 6.6  2.9 2.8 6.3  •3.9 5.0 3.3 3.4 4.5  5.1 5.2 3.4 3.7 6.5  3.8 4.9 3.2 3.4 6.8  3.3 3.7 3.3 3.6 5.7  2.8 3.0 3.3 3.1 5.8  2.6 1.7 3.2 3.1 5.5  WEEK I  WEEK 3  WEEK 5  WEEK 7  1.8  WEEK 7  WEEK 9 2.2  WEEK 11 2.2  BATCH - 11 WEEKS PARENT MATERIAL  TREATMENT TIME 0  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  Cilric Oxalic Acetic HCL HOH  2.2 1.6 2.9 2.3 5.8  2.3 1.8 3.6 4.1 6.3  2.4 1.8 3.4 4.2 7.5  2.4 1.8 3.6 3.9 7.2  2.4 1.8 3.5 3.9 7:1  3.3 3.9 6.9  Citric Oxalic Acetic HCL HOH  2.2 1.6 2.9 2.3 5.8  3.8 4.5 3.3 3.8 6.6  4.1 4.6 3.2 3.3 6.8  4.4 5.2 3.2 3.3 6.7  4.2 5.0 3.3 3.4 ' 5.9  3.9 5.1 3.2 3.4 6.7  Basalt A Basolt A Basalt A Basolt A Bosolt A  A A A A A  WEEK 9  1 7  WEEK 11 2.3 1.7 3.4 3.9  6.8 3.8 5.1 3.2 3.4 6.5  190  Appendix I :  T a b l e s o f Data from XRF A n a l y s e s o f Unweathered and Weathered G r a n o d i o r i t e and B a s a l t  X R F DATA FOR MAJOR ELEMENTAL ANALYSIS (expressed as % weight oxide I Si02  PARENT. MATERIALS  Fe203  AI203  CoO  Granodiorite  A  63.80  16.61  Granodiorite  8  63.55  16.43  49.96  15.17  12.46  51.02  15.41  50.76  12.75  Basolt  A  Bosalt  B  Howoiin  Basalt  •  A:.1-.5mm  *  B.<.1mm  MgO  K20  Na20  Mn02  5.21  4.93  2.15  2.31  3.77  5.53  4.99  2.27  2.14  3.68  8.41  9.04  0.54-  12.40  8.39  9.13  0.59 "  12.92  10.90  10.04  0.45  .  . •  .  Ti02  P205  .  S02  Total  0.11  0.50  0.11  0.02  99.52  0.13  0.54  0.10  0.02  99.38  3.38  0.16  1.51  0.25  0.02  100.90  3.41  0.18  1.50  0.25  0.02  102.30  2.33  0.16  2.38  0.23  0.02  102.94  "  EXPERIMENT I: COLUMN STUDY-4 WEEKS  PARENT  MATERIAL  Fe203 .  TREATMENT  MgO  GrDiO-A  Citric  62.13  15.28  4.95.  4.66  GrOio.A  K20  Na20  Mn02  Ti02  P205  S02  Total  1.98  2.09  3.76  0.11  0.48  0.06  0.02  95.52  OKOlic  64.90  16.81  4.42  4.95  1.95  2.21  4.04  0.10  0.51  0.05  0.02  99.96  M  GrDio.A  Acetic  63.81  16.83  4.88  4.92  2.12  2.33  4.08  0.11  0.52  0.12  0.02  99.74  VO  GrOioA  HCI  62.18  17.11  4.97  4.82  2.19  2.40  3.93  0.11  0.58  0.08  0.02  98.39  H  Gr0io.A  HOH  62.30  17.22  4.77  4.95  2.09  2.33  3.99  0.10  0.51  0.11  0.02  98.39  9.86  Basalt  A  Citric  52.24  16.48  9.23  6.17  0.65  3.72  0.13  1.68  0.22  0.02  100.40  Basalt  A  Oxalic  51.06  15.90  11.08  8.82  7.07  0.59  3.60  0.15  1.53  0.20  0.02  100.02  Bosalt  A  Acetic  50.36  15.36  11.39  8.63  7.20  0.59  3.59  0.15  1.56  0.26  0.02  99.11  Bosalt  A  HCI  50.00  15.55  11.30  8.75  7.28  • 0.58  3.47  0.15  1.58  0.26  0.02  98.94  Basalt  A  HOH  50.36  15.43  11.71  8.78  7.61  0.60  3.63  0.15  1.56  0.26  0.02  100.11  EXPERIMENT 2 BATCH STUDY - 4 WEEKS  PARENT  MATERIAL  TREATMENT  AI203  MgO  K20  Na20  Mn02  Ti02  P205  GrDioA  Citric  62.78  17.05  4.28  4.88  1.89  2.28. .  3.94  0.09  0.48  GrOio.A  Oxolic  62.49  16.51  4.71  4.89  2.13  2.34  3.94  0.09  0.52  GrDio.A  Acetic  65.84  16.84  5.16  4.95  2.20  2.27  4.23  GrDio.A  HCI  64.68  16.31  5.37  4.84  2.13  2.24  4.08  HOH  63.42  16.73  4.96  4.85  2.11  2.28  3.91  GrDio.A  •  S02  • 0.09 0.11  Total  0.02  57.78  . 0 . 0 2  97.75  0.1 1  0.52  0.12  0.02  102.26  0.11  0.50  0.12  0.02  100.40  0.11  0.51  0.11  0.02  99.01  Basalt  A  Citric  52.08  16.22  10.49  8.94  7.39  0.59  4.0S  0.13  1.54  0.25  0.02  101.73  Basalt  A  Oxalic  48.65  15.06  11.41  8.35  7.89  0.56  3.52  0.14  1.48  0.26  0.02  97.34  Basalt  A  Acetic  50.32  16.05  11.32  8.63  7.46  0.59  3.46  0.14  1.51  0.26  0.02  99.76  Bosalt  A  HCI  49.00  14.93  11.22  8.44  7.63  0.56  3.31  0 14  1.51  0.26  0.02  97.02  Basalt  A  HOH  50.93  15.73  11.62  8.74  7.49  0.62  3.66  0.15  1.56  0.27  0.02  100.81  . '  •  .  EXPERIMENT 3: COLUMN STUDY-II WEEKS PARENT  MATERIAL  TREATMENT  MqO  K20  Na20  Mn02"  G r D i o .A  Citric  64.73  16.75  4.35  4.81  1.73  .2.09  3.71  0.09  GrOio.A  Oxalic  65.11  16.24.  3.32  4.94  1.36  1.78  4.06  0.08  GrDio.A  Acetic  63.81  16.73  4.69  4.83  1.98  2.16  4 04  GrDio.A  HCl  63.70  16.71  4.76  4.79  1.91  2.18  4.26  GrOio.A  HOH  63.28  16.90  4.78  4.97  2.05  2.29  4.65  .  Ti02  P205  S02  Total  0.44  0.00  0.02  98.72  0.32  0.04  0.02  97.27  6.09  0.48  0 07  0.02  98.90  0.11  0.48  0.05  0.02  98.97  0.11  0.49  0 ) 1  0.02  99.65  99.53  '  Basalt  A  Citric  54.35  18.11  6.82  9.92  3.11  0.69  Basalt  A  Oxalic  45.19  14.69  9.28  8.31  5.34  0.57  Basalt  A  Acetic  49.89  15.50  11.26  8.67  7.26  0.56  3.60  Basalt  A  HCl  50.99  15.63  11.50  8.68  7.63  0.59  3.88  0.15  1.58  0.24  0.02  Basalt  A  HOH  49.73  14.97  11.82  8.44  7.95  0.58  3.55 .  0.14  1.52  0.26  0.02  4.62 .  3.51  0.10 .0.13  •  0.14  1.62  0.17  0.02  1.15  0.10  0.02  88.29,  1.57  0.26  0.02  98.73 ..  .  100.89 98.98  EXPERIMENT + BATCH-11 WEEKS PARENT  MATERIAL  TREATMENT  AI203  LO to  MgO  GrDio.A  Citric  63.94  16.80  4.15  4.83  1.73  GrDio.A  Oxalic  61.78  15.64  3.65  4.79  •1.28  I B ?  GrDio.A  Acetic  63.72  16.77  4.93  4.88  2.08  GrDio.A  HCl  64.61  17.02  4.65  4.92  1.87  GrDio.A  HOH  64.05  16.80  4.94  4.87  2.02  4.17  0.08  0.44  4.02  0.08  0.32  2.20  4.07  0.10  2.23  4.02  0.09  2.28  3.95  0.11  0:64  4.20  0.11  0.51  3.42  0.15  3.57  -2.0B .  0.02  0.02  0.0?  0.02  0.50  0.11  0.02.  0.45  0.12  0.02  0.50  0.12  0.02  99.66  1.64  0 24  0.02  100.64  1.31  0 16  0.02  0.15  1.56  0 ? 6  0.02  .  •  .  98.26 93.42 99.38  •  100.00  Basolt  A  Citric  54.49  17.98  7.50  9.73  4.09  Basalt  A  Oxotic  45.18  14.38  10.54  8.06  7.29  Basalt  A  Acetic  50.93  15'  1 1.76  8.65 '  7.87  0.58  Basalt  A  48.39  14.63  11.25  8.28  7.29  0.56  3.35  0.14  1.46  0.25  0 02  95.62  Bosalt  A  50.50  15.63  I i:98  8.13  8.13  0.58  3.68  0.15  1.56  0.26  0.02  100.62  . HCl HOH  70  ' •  '  .  •  91.02 '  101.05  EXPERIMENT 5; BATCH STUDY -I I WEEKS  PARENT MATERIAL  MqO  TREATMENT  K20  Ti02  P205  502  Total  Gr.Dio. 8 Gr.Dio. B Gr.Dio. B  Citric Oxolic Acetic  62.77 60.12 63.90  14.15 13.01 14.91  5.11 7.52 6.69  4.64 4.64 4.96  1.87 1.90 2.24  Bosolt 8 Bosolt B Bosolt B  Citric Oxalic Acetic  51.03 45.84 45.06  15.94 14.60 14.25  8.08 11.17 11.19  9.14 B.39 8.29  5.69 7.57 7.35  0.53 0.47 0.48  3.59 3.39 3.13  0.10 0.15 0.14  1.43 1.20 1.19  0.19 0.10 0.1!  0.02 0.02 0.02  95.74 92.90 91.21  Hawoiin Howaiin  Citric Oxolic  52.48 46.25  14.08 11.57  12.32 11.47  11.78 10.10  8.83 9.81  0.40 0.43  2.15 2.06  0.17 0.16  2.10 1.90  0.23 0.17  0.02 0.02  104.56 93.94  1.87 1.63 2.01  6.49 3.20 3.72  0.10 0.13 0.12  0.39 0.34 0.45  0.02 0.01 0.21  0.02 0.02 0.02  97.43 92.52 99.23  EXPERIMENT 6 CRUST ANALYSES BATCH EXPERIMENT -11 WEEKS  MqO  PARENT MATERIAL  K20  Na20  Mn02  Ti02  P205  S02  Total H  A A A A A  Citric Oxalic Acetic HCl HOH  39.97 37.09 63.33 62.70 63.83  11.45 9.13 16.88 16.83 16.81  6.57 16.22 4.79 5.52 4.37  2.58 3.66 4.61 4.61 4.72  3.99 2.79 2.36 2.35 2.05  3.07 1.97 2.44 2.38 2.39  1.87 1.60 3.88 3.70 3.86  0.16 0.23 0.10 0.10 0.10  1.31 0.97 0.63 0.68 0.51  Basalt A Basalt A Basalt A Basolt A Basolt A  Citric Oxalic Acetic HCl HOH  51.33  17.05  7.04  9 31  4.24  0.65  4.29  0.08  50.43 50.65  16.08 16.36  11.51 10.51  8.65 8.98  6.46 6.01  0.69 0.61  3.78 3.95  Gr.Dio. B Gr.Dio. B Gr.Dio. B  Citric Oxalic Acetic  41.63 35.06 46.69  12.23 8.11 11.96  6.20 20.21 23.17  5.43 3 79 3.49  5.18 1.52 1.98  0.45 1.27 1.90  Basalt B Basalt B Basolt B  Citric Oxolic Acetic  52.47 24.26 51.51  13.68 6.00 17.86  3.69 14.63 9.21  3 93 4.30 9.05  2.42 7.43 4.79  2.39 0.26 0 54  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  0.02 0.02 0.11 0.14 0.10.  0.02 0.02 0.02 0.02 0.02  71.01 73.70 99.15 99.03 98.76  1.60  0.23  0.02  95.84  0.15 0.13  1.58 1.56  0.27 0.27  0.02 0.02  99.62 99.05  2.82 1.68 2.47  0.09 0.17 0.08  0.97 0.41 0.54  0.08 0.00 0.41  0.02 0.02 0.02  75.10 72.24 92.71  2.95 2.47 4.03  0.12 0.19 Oil  0.66 1.15 1.31  0.15 0.28 0.25  0.02 0.02 0.02  82.48 60.99 98.68  _  '  VO W  194  T a b l e s o f C a l c u l a t i o n s o f Molar Oxide R a t i o s o f Unweathered and Weathered G r a n o d i o r i t e and B a s a l t • C a l c u l a t i o n s determined from XRF  data  EXPERIMENT I: COLUMN STUDY-4 WEEKS  PARENT MATERIAL  TREATMENT  GrDioA GrOio.A GrDio.A GrDio.A GrDioA  Cilric Oxalic Acetic HCI HOH  Basalt A Bosolt A Basolt A Bosolt A Basalt A  Citric Oxalic Acetic "HCI HOH  Si02/AI2O3  ~  Si02/R203  AI203/Fe203  BaserAlumina  Ba»e*Silica  6.87 6.75 6.56 6.06 6.12  5.72 5.68 5.53 5.15 5.20  5.00 5.33 5.33 5.67 5.67  1.40 1.44 1.44 1.35 1.29  0.20 0.21 0.22 0.22 0.21  5.44 5.31 5.60 5.53 5.60  3.95 3.70 3.82 3.82 3.82  2.67 2.67 2.14 2.14 2.14  2.31 2.50 2.60 2.67 2.73  0.42 0.47 0.46 0.48 0.49  EXPERIMENT 2 BATCH STUDY- 4 WEEKS  PARENT MATERIAL  TREATMENT  SJ02/AI203  Si02/R203  GrDio.A GrDioA GrDio.A GrDioA GrDioA  Citric Oxalic Acetic HCI HOH  6.18 6.50 6.47 6.69 6.63  5.25 5.47 5.50 5.63 5.58  5.67 5.33 5.67 5.33 5.33  1.29 1.44 1.35 1.44 1.38  0.210.21 0.21 0.21 0.21  Basolt A Bosalt A Bosolt A Bosolt A Bosolt A  Citric Oxalic Acetic HCI HOH  5.44 5.40 5.25 5.47 5.67  3.7B 3.68 3.65 3.73 3.86  2.29 2.14 2.29 2.14 2.14  2.56 2.73 2.50 2 60 2.83  0.47 0.51 0.48 0.48 0.48  AI203/Fe203  Ba»erAtumirta  Ba»ea:Silica  EXPERIMENT 3: COLUMN STUOY-1 I WEEKS  PARENT MATERIAL  TREATMENT  GrDio.A GrDio.A GrDio.A GrDio.A GrDio.A  Citric Oxolic Acetic HCl HOH  6.75 6.75 6.63 6.63 6.56  5.68 6.00 5.58 5.58 5.53  5 33 8.00 5 33 5.33 5.33  1.31 1.25 1.37 1.44 1.50  0.19 0.18 0.21 0.22 0.23  Bosolt Basalt Basalt Bosalt Bosolt  Citric Oxolic Acetic HCl HOH  5.00 5.36 5.53 5.67 5.53  4.09 3.75 3.77 3.86 3.77  4.50 2.33 2.14 2.14 2.14  1.89 2.50 2.67 2.73 2.80  0.38 0.47 0.48 0.48 0.51  A A A A A  Si02/AI203  Si02/R203  AI203/Fe203  Ba*e*Alumina  BaaeeSilka  EXPERIMENT 4: BATCH- I I WEEKS PARENT MATERIAL  GrDio.A GrDio.A GrDio.A GrDio.A GrOio.A Bosalt Basalt Basalt Basalt Basalt  A A A A A  _  TREATMENT  Si02/AI203  Si02/R203  AI203 -Fe203  Ba»ct Akjmrva  BaaerSilica  Citric O.ulic Acetic ' HCl HOH  6.63 6.87 6.63 6.29 6.69  5.58 6.06 5.58 5.35 5.63  5.33 7.50 533 5.67 5.33  1.37 1.33 1.37 1.29 1.37  0.21 0.19 0.21 0.21 0.21  Citric Oxalic Acetic HCl HOH  5.06 5.36 5.67 5.79 5.60  3.96 3.57 3.86 3.86 3.65  3.60 2.00 2.14 2.00 1.88 .  3.50 2.79 2.73 2.79 2.80  0.38 0.52 0.48 0.48 0.50  EXPERIMENT S BATCH STUDY-11 WEEKS PARENT MATERIAL  TREATMENT  Gr.Dio. B Gr.Dio. B Gr.Oio. B  Citric Oxalic Acetic  Basalt B Basalt B Basolt B Hawaiin Hawaiin  Si02/AI203  AI203/Fe203  Bases^Alumina  BaserSiltca  7.43 7.69 7.07  4.67 2.60 3.75  1.79 1.54 1.53  0.24 0.20 0.22  Citric Oxalic Acetic  5.31 5.43 5.54  3.20 2.00 2.00  2.31 2.44 2.71  0.43 0.51 0.51  Citric Oxalic  6.21 7.06  1.75 1.75  3.29 4.09  0.53 0.58  .  '  EXPERIMENT 6= CRUST ANALYSES B A T C H EXPERIMENT-11 W E E K S  Si02/AI203  AI203/Fe203  Bases: Alumina  Bases^Silica  PARENT MATERIAL  TREATMENT  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  A A A A A  Citric Oxalic Acetic HCI HOH  6.09 6.89 6.18 6.12 6.63  2.75 0.90 5.66 5.66 5.33  1.90 2.11 1.35 1.35 1.37  0.31 0.31 0.22 0.22 0.21  Basalt Basolt Basolt Basalt Bosolt  A A A A A  Citric Oxalic Acetic HCI HOH  5.00 * 5.25 5.25 x  4.25 x' 2.29 2.29 x  2.00  0.40  2.31 2.31  0.44 0.44  Gr.Oio. B Gr.Dio. B Gr.Dio. B  Citric Oxalic Acetic  5.75 7.25 6.50  3.00 0.62 0.80  Basolt B Basolt B Bosalt B  Citric Oxalic Acetic  6.69 6.67 4.78  6.50 0.67 3.00  2.25 1.87 1.42 1.62 5.00 1.89 3.55  0.39 0.26 0.22 0.24 0.70 0.40 0.53  Hawaiin  Citric  6.64  1.83  X  198  Appendix  :  T a b l e s o f Data from XRD A n a l y s e s o f Unweathered and Weathered G r a n o d i o r i t e and B a s a l t .  X-RAY DIFFRACTION A N A L Y S E S GRANODIORITE- COLUMN EXPERIMENT MINERAL  Micas Hornblende K-Spar Plagioclase K-Spar Ilmenite Plagioclase Q u a r t z / Micas Plagioclase Hornblende Pyroxene/Magnetite Pyroxene F e - silicate Biotite Magnetite/Hematite Quartz T i t a n i t e / Hematite Periclase Micas Quartz F e - silicate Magnetite/Hematite  ANGLE 20  8.885 10.557 20.973 22.071 22.943 23.798 24.445 26.711 28.061 28.365 29.788 30.537 31.605 33.951 35.692 36.702 39.586 42.513 45.084 50.283 51.525 54.944  D-SPACE  •  9.5220 8.3794 4.2356 4.0272 3.8761 3.7388 3.6413 3.3373 3.1758 3.1463 2.9992 2.9273 2.8308 2.6404 2.5155 2.4485 2.2766 2,1263 2.0109 1.8145 1.7736 1.6711  INTENSITY UNWEATHERED 598 121 220 92 108 59 94 1340 1194 118 57 112 55 72 126 91 62 128 93 248 128 73  CITRIC ACID WKS- 4 62 57 167 155 55 125 117 1222 407 137 67 129 136 67 115 104 98 104 47 140 90 58  O X A L I C ACID  WKS- 1 115 N.D. 155 . 180 65 106 111 1222 598 206 92 133 77 59 116 137 126 68 N.0. 176 73 66  VKS- 4  WKS- 11  64 73 170 156 77 106 138 1026 760 N.D. 101 160 86 61 115 100 125 97 • 54 82 55 60  143 104 194 155 . N.0. 111 139 1186 1027 N.D. 80 137 106 61 108 ' 110 142 . 123 55 203 68 . 73  A C E T I C ACID WKS- 4 116 60 176 • 136 79 119 107 1254 1130 151 103 130 120 N.D. 103 114 100 . 78 68 169 66 62  WKS- 11 109 69 140 157 NO. 136 112 768 591 141 116 134 103. N.D. 204 130 111 99 N.D. 83 81 62  HCl WKS- 4 107 N.D. 175 149 66 131 119 1240 748 N.D. 84 140 97 65 108 76 71 73 57 168 69 N.D.  HOH WKS- 11 129 N.D. 199 168 66 96 105 1158 818 175 137 143 ' 87 N.D. 122 108 106 88 N.D. 124 74 67  •WKS- 4 105. 61 129 178 73 104 154 776 540 120 93 132 90 58 104 100 92 71 N.D. 89 81 63  WKS  -1  159 68 148 149 N.D. 143 120 1272 467 132 61 148 108 N.D. 100 65 96 114 N.D. 118 66 N.D.  GRANODIORITE- B A T C H EXPERIMENT MINERAL  Micas Hornblende K-Spar Plagioclase K-Spar Ilmenite Plagioclase Q u a r t z / Micas Plagioclase Hornblende P r o x e n e / Magnetite Pyroxene F e - silicate Biotile Magnetite/Hematite Quartz T i l a n i t e / Hematite Perictase Micas Quartz F e - silicate Magnetile/Hematile  ANGLE 20  8.885 10.557 20.973 22.071 22.943 23.798 24.445 26.711 28.061 28.365 29.788 30.537 31.605 33.951 35.692 36.702 39.586 42.513 45.084 50.283 51.525 54.944  D-SPACE  9.5220 8.3794 4.2356 4?0272 3.8761 3.7388 3.6413 3.3373 3.1758 3.1463 2.9992 2.9273 2.8308 2.6404 2.5155 2.4485 2.2766 2.1263 2.0109 1.8145 1.7736 1.6711  INTENSITY UNWEATHERED 598 121 220 92 108 59 94 1340 1194 118 57 112 55 72 126 91 62 128 93 248 128 73  CITRIC ACID WKS- 4 105  105 55 220 150 92 145 154 1189 563 96 78 144 97 77 114 8789 67 N.D. 92 75 39  WKS - 11 147 65 167 157 66 117 160 999 813 166 88 124 117 58 125 127 113 113 NO. 117 83 62  O X A L I C ACIO WKS- 11  WKS- 4 N.D. N.D. 114 81 N.D. 65 57 611 488 81 68 107 60 66 79 89 96 69 N.D. 110 72 50  N.0. N.D. 121 99 N.D. 64 62 616 496 79 72 60 N.D N.D. 61 63 61 87 NO. 76 NO. 52  A C E T I C ACID WKS- 4 162 79 159 158 83 98 118 1061 587 161 94 153 90 NO. 97 98 89 69 54 145 51 66  WKS- 11 126 61 226 133 55 198 124 1295 688 203 78 135 92 N.D. 99 220 104 118 N.0. 237 83 56  HCl WKS- 4' 161 81 182 158 81 94 123 1524 710 107 92 170 67 N.D. 101 175 69 83 80 166 79 68  HOH WKS- 11 150 60 174 133 55 57 110 1295 687 101 78 135 92 N.D. 99 150 98 67 56 116 98 • 70  WKS- 4  WKS - 1  85 76 167 145 62 108 120 869 521 84 72 133 77 N.D. 131 109 95 107 N.D. 167 60 N.D  166 48 167 127 N.D. 148 119 887 1013 154 100 187 80 N.D. 92 95 105 52 N.D. 119 92 N.D.  B A S A L T - COLUMN EXPERIMENT MINERAL  Ox-Precipitate Plagioclase Forsterite Plagioclase a 1 Plagioclase b 1 Fayalite M i c a s / Ouartz a) Plagioclase b l Hypersthene Hornblende Pyroxene Pyroxene Hypersthene Fayalile Hornblende a 1 llmentte b 1 Fayalite a 1 Magnetile b l Fayalite c 1 Hematite Ouarlz Periclase Ox- Precipitate Hematite Fayalite llmenile  ANGLE 20  0-SPACE  INTENSITY UNWEATHERED  CITRIC ACID WKS- 4 WKS- 11  18.290 22.120 22.952 23.770 24.562 " 26.554 27.908 " 28.508 29.858 30.440 30.827 31.602 32.199 35.008 "  4.8503 4.0184 3.8746 3.7431 3.6242 " 3.3567 3.1968 " 3.1309 2.9923 2.9364 2.9004 2.8310 2.7799 2.5630 "  N.D. t51 69 227 1 1 6 . " 72 425 " 164 161 161 73 94 N.D. 61 "  N.D. 190 65 376 139 " 92 '645 "  35.659  2.5177  175 .  165  2.4650 2.1329 2.0213 1.8300 1.7710 1.7496  " N.D. 87 N.D. N.D. 150 60  36.448 42.376 44.840 49.828 51.608 52.286  126 197 , 165 64 91 N.D. 71  57 125 N.D. 75 86 53  N.D. 157 62 310 ' 115 *'  76 298 " 69 . 139 158 62 88 N.D. 66 " 144 " 34 76 N.D. 66 61 47  OXALIC A C D WKS- 4 WKS- 11 N.D. 143 72 220 123 " 82 433 " 150 168 150 70 90 ' 82 90 " 170 " " 79 81 N.D. 73 N.D. 54  132 129 96 189 113 " N.D. 507 " 168 162 142 N.D. 70 N.D. 81 " 133 " " 96 102 N.D. 62 58 89  A C E T I C ACS) WKS- 11 WKS- 4 N.D. 152 . 94 166 116 " 66 425 " 157 194 140 54 79 80 73 " 167 " " 160 99 N.D. 69 57 59  N.D. 133 74 172 101 " N.D. 342 " 140 133 152 79 74 59 61 " 158  HCI WKS- 4 N.D. 161 60 178 H2 " 67 421 " 121 191 156 77 74 59 61 " 170  " " 89 77 N.D. 68 73 74  " 84 78 N.D. " 63 61 73  WKS- 11  WKS- 4  HOH WKS -  N.D. 138 121 189 133 " N.D. 337 " 116 163 167 107 98 N.D. 69 " 173 "  N.D. 155 56 173 118 " 60 254 " N.D. 150 119 68 69 121 63 " 233  N.D. 163 63 220 96 " 72 470 " N.D. 176 150 64 100 110 75 " 156  62 80 N.D. 68 66 64  87 77 N.D. 67 N.D. 81  " 112 71 N.D 68 84 76  B A S A L T - B A T C H EXPERIMENT MINERAL  Ox-Precipitate Plagioclase Forsterite Plagioclase a l Plagioclase b l Fayalite M i c a s / Quartz a 1 Plagioclase b l Hypersthene Hornblende Pyroxene Pyroxene Hypersthene Fayalite Hornblende a i llmenite' b l Fayalite a) Magnetite b l Fayalite c 1 Hematite Quartz' Periclase Ox-Precipitate Hematite Fayalite llmenite .  ANGLE 20  D-SPACE  INTENSITY UNWEATHERED  CITRIC ACID WKS- 4 WKS-,11  O X A L I C ACID WKS- 4 WKS- 1 1  18.290 22.120 22.952 23.770 24.562 " 26.554 27.908 "  4.8503 4.0184 3.8746 3.7431 3.6242  N.D. 151 69 227 116 "  N.D. 185 70 238 158 "  . N.D. 152 71 186 116 "  N.D. 116 73 230 112 "  3.3567 3.1968  72 425 "  75 406 "  65 295 "  75 380  28.508 29.858 30.440 30.827 31.602 32.199 35.008 "  3.1309 2.9923 2.9364 2.9004 2.8310 2.7799 2.5630 "  160 217 140 64 84 61 68 "  59 124 146 N.D. 56 N.D. 56 "  98 196 136 70 90 N.D. 71 "  35.659 "  2.5177  2.4650 2.1329 2.0213 1.8300 1.7710 1.7496  161 " " N.D. 82 N.D. 72 N.D. N.D.  223 "  36.448 42.376 44.840 49.828 51.608 52.286  188 " " 95 87 N.D. 76 64 56  164 161 161 73 94 " N.D. 61 " 175 " "  ,  N.D. 87 N.D. N.D. 150 60 .,  87 85 N.D. N.D. 60 94  117 199 55 144 154 " 77 300 " N.D. 172 143 57 63 N.D. 76 " • 123  64 81 83 79 N.D. 67  HCI WKS- 4  ACETIC A C D WKS- 4 WKS- 11  78 308  N.D. 168 52 212 130 " 75 465  181  116 161 161 N.D. 79 93 65 " 222  129 207 126 N.D. 85 87 83 " 179  66 99 N.D. 100 • 86 59  " " 77 78 N.D. 57 64 64 '  " " 69 97 N.D. 64 89 50  N.D. 160 68 225 150 " 76 411 " • 123 159 164 N.D. 97 N.D. 72 "  N.D. 141 62 223 146 " 86 354 " 86 150 173 N.D. 104 N.D. 78  181  70 89 N.D. 81 103 60  N.D. 157 69 179 107  WKS- 11 '  -  WKS- 4.  HOH WKS -  N.D. 127 70 172 107  N.D. 129 52 153 96  60 • 345  " 71. 435  " 90 126 168 N.D. 88 83 88  " 55 150 139 66 81 60 53  157 " 97 79 N.D. 59 N.D. 62  .  " 219  92 149 N.D. 58 83 107  Appendix K : 2  T a b l e s o f Data from XRD A n a l y s e s o f G r a n o d i o r i t e and B a s a l t i c " c r u s t " .  204  Angle 20  D-Spacing  Intensity  Mineral  18.616 21.037 22.127  4.7661 4.2229 4.0173  195 55 60  23.055 23.907  3.8575 3.7220  83 62  24.563 26.734  3.6241 3.3345  82 367  28.051 28.385  3.1808 3.1442  229 71  29.677  3.0102  83  30.498  2.9310  63  31.594  2.8317  85  34.502 35.618 36.803  2.5994 2.5205 2 .4421  82 53 54  39.610  2.2752  58  50.308  1.8136  86  Fe ( I I ) O x a l a t e D i h y d r a t e Quartz a) P l a g i o c l a s e b) Fe ( I I ) O x a l a t e Oxalic Acid a) K - F e l d s p a r b) P l a g i o c l a s e Plagioclase a) Micas b) Quartz Plagioclase a) P l a g i o c l a s e b) Hornblende a) P l a g i o c l a s e b) Pyroxene a) Pyroxene b) K - o x a l a t e a) C a - o x a l a t e h y d r a t e b) Na-oxalate Mica K-oxalate per hydrate a) o x a l i c A c i d b) K - o x a l a t e a) Hematite b) K - o x a l a t e Quartz  Table:  I d e n t i f i c a t i o n o f XRD peaks f o r G r a n o d i o r i t e / O x a l i c Acid Crust.  Source:  Batch experiment  - 11 week weathering  study.  205 Angle 2 0  D-Spacing  Intensity  Mineral  22.120 22 .945 23.824  4.0184 3.8758 3.7347  196 77 257  24-577 25.744  3.6221 3.4604  140 66  26.577  3.3538  95  27.912 29.832  3.1964 2.9949  586 135  30.801 31.671 32.749  2.9028 2.8250 2.7345  81 100 60  Plagioclase Forsterite a) P l a g i o c l a s e b) I l m e n i t e Fayalite a) T i t a n i u m Oxide b) K, A l , S i l i c a t e h y d r a t e a) Quartz b) Mica Plagioclase a) Pyroxene (Augite) a) P l a g i o c l a s e b) Pyroxene b) P l a g i o c l a s e Pyroxene (Pigeonite) Fayalite a) I l m e n i t e b) C a S i 0 c) K Mg S i 0 Hematite a) M a g n e t i t e b) I l m e n i t e Hematite a) P e r i c l a s e b) Quartz T i t a n i u m Oxide a) Quartz b) Hematite Fayalite/Forsterite Ilmenite 2  33.912 35.112  2.6433 2.5557  65 64  35.735 42.312  2.5125 2.1360  190 105  48.570 49.873  1.8744 1.8284  80 66  51.628 52.300  1.7703 1.7491  83 55  Table: Source:  ?  4  4  I d e n t i f i c a t i o n o f XRD peaks f o r B a s a l t / C i t r i c A c i d Batch experiment - 11 week weathering s t u d y .  Crust.  206 Angle 20  D-Spacing  Intensity  Mineral  8.719 20.856  10.1411 4.2592  117 91  21.954 23.724  4.0486 3.7503  112 74  24.299 26.563 27.869 29.697  3.6628 3.3555 3.2013 3.0082  76 422 195 64  30.346  2.9454  108  33.997 35.432 36.003  2.6369 2.5333 2.4945  131 73 58  36.640 39.403 41.305 45.003 49.825 51.391  2.4526 2.2867 2.1857 2.0143 1.8301 1.7779  103 72 74 61 54 82  54.622  1.6801  54  Mica a) K - F e l d s p a r b ) Quartz Plagioclase a) F e l d s p a r b ) Ilmenite Plagioclase Quartz and Mica Plagioclase a) K - F e l d s p a r b ) Plagioclase a) P l a g i o c l a s e b ) K-Feldspar c) Pyroxene Hematite Magnetite a) F e - s i l i c a t e b ) Hematite Quartz a) N u t i l e / A n a t a s e Hematite Mica Quartz a) I l m e n i t e b ) Fe-silicate a) Hematite b ) Magnetite  Table:  I d e n t i f i c a t i o n o f XRD peaks f o r G r a n o d i o r i t e / C i t r i c A c i d Crust.  Source: Batch experiment - 11 week weathering study.  207  Angle 20  D-Spacing  Intensity  Mineral  18.336  4.8382  822  a) Mg - o x a l a t e h y d r a t e b) Fe - o x a l a t e h y d r a t e c) Na-Fe ( I I ) O x a l a t e Nona Hydrate  23.226  3.89295  130  a) O x a l i c  acid  b) F a y a l i t e 23.849  3.7310  76  28.404  3.1421  356  34.946  2.5674  153  37.969  2.3697  93  43.178  2.0951  124  44.724  2.0262  179  Albite a)  Ca-Oxalate  b) Pyroxene Fayalite a) C a - o x a l a t e  48.794  Table Source:  b) Mg - o x a l a t e h y d r a t e Unidentified  a) Mg-oxalate h y d r a t e b) F e - o x a l a t e h y d r a t e a) C a - o x a l a t e b) Fe-Oxalate h y d r a t e I d e n t i f i c a t i o n o f XRD peaks f o r B a s a l t / O x a l i c A c i d C r u s t 1.8663  109  Batch Experiment  - 11 week weathering  study.  208  Appendix L:  T a b l e s o f Data from CEC and S u r f a c e Area A n a l y s e s o f Unweathered and Weathered and Unweathered G r a n o d i o r i t e and B a s a l t .  2 0 9  GRANODIORITE AND BASALT UNWEATHERED AND WEATHERED RESIDUES: CEC. SPECIFIC SURFACE AND SURFACE CHARGE DENSITY PARENT MATERIALS  CEC  UNWEATHERED  (me/lOOg)  Granodiorite A Granodiorite ite B Basalt A Basalt B Hawaiin Basalt  CHARGE DENSITY (Tl  SPECIFIC SURFACE (m /g)  ( m e / m ) ) x 10"'  l  0.6 1.1 0.7 1.1 0.3  1  2.0 2.8 1.5 1.9 2.0  3.2 3.9 4.9 5.5 1.7  *A:. 1 mm-.5mm «B:<.lmm EXPERIMENT 1 = COLUMN STUDY-4 WEEKS PARENT MATERIAL  TREATMENT  SPECIFIC SURFACE  CEC (me/IOOg)  (m /9) l  CHARGE DE (me/m ] 2  GrDio. A GrDio. A GrDio. A GrDio. A GrDio. A  Citric Oxalic Acetic HCL HOH  1.0 1.5 1.0 1.0 1.9  3.1 4.5 3.1 5.2 14.1  3.2 3.2 3.2 1.8 1.3  Basalt A Basalt A Basalt A Basalt A Basalt A  Citric Oxalic Acetic HCL HOH  1.8 3.9 2.2 1.2 1.1  3.9 5.2 3.5 4.2 2.1  4.7 7.4 6.3 3.0 5.2  EXPERIMENT 2' BATCH STUDY-4 WEEKS PARENT MATERIAL  TREATMENT  SPECIFIC SURFACE  CEC (me/100g)  (m*/9)  CHARGE DE (me/m2;  GrDio. A GrDio. A GrDio. A GrDio. A GrDio. A  Citric Oxalic Acetic HCL HOH  2.2 2.7 1.8 0.8 0.9  5.2 4.6 4.3 4.9 12.9  5.9 4.3 1.7 1.0  Basalt A Basalt A Basalt A Basalt A Basalt A  Citric Oxalic Acetic HCL HOH  3.5 2.3 1.4 1.0 1.9  9.8 8.1 3.5 4.5 7.3  3.6 2 S 4.0 2.3. 2.6  4.3  210  EXPERIMENT 3: COLUMN STUDY-1 1 WEEKS PARENT MATERIAL  TREATMENT  CEC  SPECIFIC SURFACE  (me/lOOg)  GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  2.6 2.8 1.0 'l.O 1.8  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  3.9 2.9 5.0 7.9 2.7  .  (m»/g)  CHARGE DENSITY (T I (me/m ^ ) x 10" 3  8.0 .  S.5 2.8 3.5 5.9  3.5 3.0 3.0  6.5 4.6 9.0 1 1.5 . 6.0  6.0 6.3 5.5 6.5 4.5  EXPERIMENT 4:BATCH-lt WEEKS PARENT MATERIAL  TREATMENT  \ GrDio. GrDio. GrDio. GrDio. GrDio.  A A A A A  Citric Oxalic Acetic HCL HOH  Basalt Basalt Basalt Basalt Basalt  A A A A A  Citric Oxalic Acetic HCL HOH  CEC  SPECIFIC SURFACE  (me/lOOg)  •  CHARGE DENSITY (Tl (me/m  (mVg)  1  1.1 • 4.1 2.7 1.9 2.0  4.2 9.8 8.0 7.8 6.9  2.6 4.2 3.4 2.4 2.9  3.9 3.1 • 4.0 3.5 3.2  6.2 6.0 9.1 4.2 7.6  6.3 5.2 4.5 8.4 4.2  ) » 10"  J  EXPERIMENT 5: BATCH-1 I WEEKS PARENT MATERIAL  TREATMENT  CEC (me/lOOg)  SPECIFIC SURFACE (mVg)  CHARGE DENSITY (Tl 10•3 (me/m 2 )  GrDio. B GrDio. B GrDio. B  Citric Oxalic Acetic  2.3 2.4 1.7 .  11.2 1.2.1 10.3  2.1 2.0  Basalt B Basalt B Basalt B Hawaiin B Hawaiin B  Citric Oxalic Acetic Citric Oxalic  3.9 3.6 2.1 1.0 2.5  7.8 13.1 3.1 4.0 10.9  4.9 2.8 6.7 2.5 2.3  ' ••  211  Appendix M:  T a b l e s o f Data from Exchangeable Bases A n a l y s e s o f Unweathered and Weathered Analyses.  212  E X C H A N G E A B L E B A S E S OF UNWEATHERED AND WEATHERED RESIDUES Imeq/lOOg PARENT MATERIALS Calcium Granodiorite A Granodiorite B Basalt A Basalt B Hawaiin Basalt  0.53 0.70 0.24 0.39 0.14  EXCHANGEABLE BASES Magnesium Sodium 0.03 0.09 0.11 0.27 0.06  (meq/IOOgl  0.11 0.18 0.12 0.20 0.04  Potassium 0.25 0.20 0.10 0.09 0.03  *A:. l-.Smm *B:< 1 mm E X P E R I M E N T 1: COLUMN STUDY-4 W E E K S PARENT MATERIAL  TREATMENT Calcium  (meq/10Og I Sodium  Potassium  A A A A A  Citric Oxalic Acetic HCL HOH  0.06 0.24 0.36 0.37 0.54  0.44 0.25 0.02 0.03 0.28  0.04 0.08 0.04 0.06 0.05  0.14 0.22 0.12 0.1 1 0.1 1 .  A A A A A'  Citric Oxalic Acetic HCL HOH  0.05 0.49 0.10 0.22 0.36  1.14 1.16 0.04 0.51 0.12  0.63 0.03 0.03 0.06 0.04  0.16 0.05 0.04 0.05 0.04  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Basalt Basalt Basalt Basalt Basalt  EXCHANGEABLE B A S E S Magnesium  EXPERIMENT 2- BATCH STUDY-4 W E E K S EXCHANGEABLE B A S E S PARENT MATERIAL  (meq/1 OOg I  TREATMENT Calcium  Magnesium  Sodium  Potassium  Gr.Dio. A Gr.Dio. A Gr.Dio. A Gr.Oio. A Gr.Dio. A  Citric Oxalic Acetic HCL HOH  0.10 0.22 0.23 0.56 0.61  0.40 0.59 0.07 0.12 0.08  0.04 0.05 0.07 0.07 0.09  0.13 0.23 0.15 0.17 0.13  Basalt Basalt Bosalt Bosalt Basolt  Citric Oxalic Acetic HCL HOH  0.06 0.44 0.14 0.34 0.29  0.07 1.18 0.07 0.17 0.18  0.02 0.04 0.06 0.08 0.08  0.03 ' 0.06 0.06 0.09 0.06  A A A A A  213  EXPERIMENT 3: COLUMN STUDY-11 W E E K S PARENT MATERIAL  TREATMENT Calcium  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  A A A A A  Basalt A Basalt A Basalt A Basalt A Basalt A  EXCHANGEABLE B A S E S Magnesium  Sodium  (meq/ 1 OOg 1 Potassium  Citric Oxolic Acetic HCL HOH  0.03 0.07 0.17 0.13 0.58  0.62 1.02 0.13 0.14 0.05  0.06 0.07 0.05 0.04 0.06  0.25 0.59 0.06 0.07 0.26  Citric Oxalic Acetic HCL HOH  0.02 0.29 0.09 0.08 0.32  1.16 1.41 0.27 0.19 0.14  0.10 0.15 0.09 0.10 0.06  0.20 0.10 0.08 0.0S 0.08  EXPERIMENT 4> BATCH STUDY-11 W E E K S PARENT MATERIAL  Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio. Gr.Dio.  A A A A A  Basalt A Bosolt A Basalt A Basalt A Basalt A  TREATMENT  Citric Oxalic Acetic HCL HOH  Calcium 0.03 0.14 0.23 0.19 0.42  Citric Oxolic Acetic HCL HOH  0.00 0.27 0.09 0.10 0.35  EXCHANGEABLE BASES Magnesium 0.87 0.98 0.12 , 0.09 0.14 6.46 10.13 0.12 0.07 0.16  (meq/10Og I Sodium 0.06 0.06 0.04 0.04 0.05  Potassium 0.39 0.58 0.10 0.33 0.12  0.05 0.05 0.05 0.05 0.05  0.05 0.15 0.67 0.29 0.93  EXPERIMENT S< B A T C H STUDY-11 W E E K S PARENT MATERIAL  TREATMENT  EXCHANGEABLE B A S E S Magnesium 1.18 0.95 0.13  'meq/1 OOg 1 Sodium  Potassium 0.35 0.51 0.11  Gr.Dio. B Gr.Dio. B Gr.Dio. B  Citric Oxalic Acetic  Calcium 0.19 0.11 0.43  Bosalt B Basolt B Basalt B  Citric Oxalic Acetic  0.02 0.45 0.06  1.10 1.36 0.19  0.09 0.15 0.09  0.50 0.07 0.77  Hawaiin Hawaiin  Citric Oxolic  0.06 0.20  1.22 0.88  0.07 0.16  0.08 0.23  0.14 0.14  0.05  214  A p p e n d i x Note:  N :  M a s s  B a l a n c e  C a l c u l a t i o n s  The v a l u e s may be used o n l y f o r the b a s i s o f approimate comparisons f o r the f o l l o w i n g reasons: 1. 2. 3. 4.  C o l l o i d a l m a t e r i a l may o v e r e s t i m a t e values from s o l u t i o n and e x t r a c t a b l e Fe, A l , and S i analyses. V a l u e s f o r e x t r a c t a b l e Fe, A l , and S i are not a d d i t i v e but i n f a c t o v e r l a p . C o n c e n t r a t i o n s o f i o n s i n s o l u t i o n s may l a t e r form p r e c i p i t a t e s and c o n t r i b u t e t o both s o i i d and s o l u t i o n a n a l y s e s . V a l u e s f o r e x t r a c t a b l e A l and S i are l e s s a c c u r a t e than f o r e x t r a c t a b l e Fe.  215 M A S S  B A L A N C E  C A L C U L A T I O N S Ca  I .  2 +  B A T C H  , M g  2  +  A N D  C O L U M N  , Na , K +  E X P E R I M E N T  +  G R A N O D I O R I T E - % C a O  TREATMENT Citric Oxalic Acetic HCL HOH  A 4.93 4.93 4.93 4.93 4.93  BCH 0.77 0.37 0.19 0.14 0.03  BCH 20.20 7.45 3.89 2.80 0.63  COL 0.51 0.24 0.27 0.34 0.02  COL 10.30 4.92 5.55 6.83 0.44  0.43 0.13 0.12 0.17 0.01  5.15 1.60 1.49 2.07 0.15  0.46 0.13 0.15 0.18 0.00  5.46 1.57 1.84 2.20 0.00  0.40 0.61 0.03 0.04 0.01  18.76 28.57 1.61 1.66 0.57  0.20 0.45 0.03 0.06 0.00  9.20 20.93 1.62 2.86 0. 00  3.83 0.51 0.03 0.04 0.00  42.36 5.62 0.29 0.39 0.00  2.98 1.07 0.06 0.06 0.00  32.93 11.80 0. 69 0.69 0.00  B  C  D  E  I I . B A S A L %T C -a O 8.41 8.41 8.41 8.41 .8.41  Citric Oxalic Acetic HCL HOH I .  G R A N O D I O R I T E - % M g O 2.15 2.15 2.15 2.15 2.15  Citric Oxalic Acetic HCL HOH  I I . B A S A L T - % M g O Citric Oxalic Acetic HCL HOH  9.04 9.04 9.04 9.04 9.04  A = % Oxide i n unweathered m a t e r i a l BCH l % o x i d e i n 11 wks b a t c h l e a c h a t e BCH = % B o f A COL l * o x i d e i n 11 wks b a t c h l e a c h a t e B  =  T  o  t  a  =  T  o  t  a  C D  Eorvr = % D O f A  216 M A S S I .  B A L A N C E  C A L C U L A T I O N S  G R A N O D I O R I T E - %  T R E A T M E N T  A  B  3.77 3.77 3.77 3.77 3.77  Citric Oxalic Acetic HCL HOH  B A T C H  & C O L U M N  E X P E R I M E N T  N a 0  BCH  2  C  BCH  D  COL  E  CO]  0.05 0.06 0.02 0.02 0.01  1.33 1.70 0.56 0.42 0.31  0.03 0.05 0.01 0.01 0.01  0.77 1.28 0.35 0.39 0.16  0.03 0.04 0.03 0.03 0.01  0.97 1.14 0.87 0.93 0.34  0.03 0.04 0.01 0.02 0.00  0.70 1.40 0.17 0.59 0.00  0.51 1.16 0.13 0.10 0.04  21.98 50.19 5.45 4.30 1.74  0.29 0.90 0.06 0.07 0.01  12.76 39.04 2.50 3.10 0.58  0.01 0.01 0.01 0.01 0.00  1.61 1.03 1.64 1.68 0.00  0.01 <0.01 0.00 0.00 0.00  1.50 1.00 0.00 0.00 0.00  I I . B A S A L TN a- 0% 2  3.38 3.38 3.38 3.38 3.38  Citric Oxalic Acetic HCL HOH I .  G R A N O D I O R I TK E0 - % 2  Citric Oxalic Acetic HCL HOH  2.31 2.31 2.31 2.31 2.31  I I . B A S A L T K -0 % 2  0.54 0.54 0.54 0.54 0.54  Citric Oxalic Acetic HCL HOH  A = % Oxide i n unweathered m a t e r i a l BCH % oxide i n 11 wks Batch l e a c h a t e BCH = % °f COL o x i d e i n 11 wks Batch l e a c h a t e E L = % D of A B  =  T  o  t  =  T  o  t  C  a  l  B  D  C 0  a  A  l  %  M A S S I .  C A L C U L A T I O N S  C O L U M N  E X P E R I M E N T  G R A N O D I O R I T E % F e ~ 0 A  TREATMENT Citric Oxalic Acetic HCL HOH I I  = = = = = = =  C  D  E  F  G  H  1.17 3.17 . 0.13 0.19 0.00  0.20 6.92 0.06 0.03 0.03  1. 52 2. 23 2. 34 1. 83 1. 37  3. 66 1. 00 1. 00 0.86 0.86  22.48 60.85 2.49 3.61 0.00  70.26 19.21 19.21 16.47 16.50  92.74 80.06 21.70 20.08 16.50  9.51 2.85 0.32 0.35 0.00  0.34 18.59 1.29 0.03 0.00  1. 66 3. 00 3. 98 3. 86 4.46  0.43 6.95 1. 14 1. 09 1. 00  76.30 22.83 2.60 2.80 0.00  3.44 55.78 9.18 8.72 8.03  79.74 78.61 11.78 il.52 8.03  B  5.21 5.21 5.21 5.21 5.21  B A S A L • T %- F e 0 2  Citric Oxalic Acetic HCL HOH A B C D E F G  B A L A N C E  3  12.46 12 .46 12.46 12.46 12.46  % Oxide i n unweathered m a t e r i a l T o t a l % o x i d e i n 11 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e % oxide Ammonium O x a l a t e e x t r a c t a b l e % oxide CBD e x t r a c t a b l e % oxide % B of A % E of A  ^4  M A S S I .  C O L U M N  E X P E R I M E N T  2  Citric Oxalic Acetic HCL HOH  B 0.82 2.19 0.10 0.12 0.00  16.61 16.61 16.61 16.61 16.61  I I . B A S A L T % A1 0 2  Citric Oxalic Acetic HCL HOH = = = = = = = =  C A L C U L A T I O N S  G R A N O D I O R I T E % A1 03 A  A B C D E F G H  B A L A N C E  15.,17 15.,17 15.,17 15.,17 15..17  D  C 0.11 0.08 0.04 0.04 0.00  0.26 0.15 0.45 0.45 0.38  E 0.23 0.30 0.30 0.26 0.26  F 4.91 13.19 0.60 0.71 0.00  G 1.37 1.82 1.82 1.59 1.59  H 6.28 15.01 2.42 2.30 1.59  to  3  0..12 0.,29 0.,07 0..05 0..00  0..00 0..04 0..04 0..00 0..00  0..30 0.,00 0..30 0..30 0..38  % Oxide i n unweathered m a t e r i a l T o t a l % o x i d e i n 11 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e % o x i d e Ammonium O x a l a t e e x t r a c t a b l e % oxide CBD e x t r a c t a b l e % oxide % B of A % E of A % t o t a l oxide removed (F + G)  0..08 0.,04 0.,15 0.,19 0.,15  0..82 1.,88 0..48 0..35 0..00  0.,53 0,,25 1.,00 1,,25 1.,00  1..35 2.,13 1..48 1..60 1..00  M CO  M A S S 1.  G R A N O D I O R I T E % 8i0 B  A Citric Oxalic Acetic HCL HOH  63 63 63 63 63  .80 .80 .80 .80 .80  I I . B A S A L T %- s i o Citric Oxalic Acetic HCL HOH A B C D E F G H  = = = = = = = =  49 49 49 49 49  .96 .96 .96 .96 .96  B A L A N C E  C A L C U L A T I O N S  C O L U M N  E X P E R I M E N T  2  D  C  E  F  G  H  0..56 1..42 0..02 0..01 0..00  0..38 0..79 0..09 0., 00 0..00  0.,00 0..00 0..00 0.,00 0.,00  0. 38 0. 21 0. 21 0. 17 0. 17  0.,88 2..24 0..03 0..02 0..00  0.,60 0.,34 0..34 0.,27 0..27  1..40 2..58 0..37 0..29 0..27  4..26 4..26 0..10 0..09 0.,00  1..01 0..96 0..13 0..09 0.,00  0..00 0..00 1.,11 1..11 1.,28  0. 38 0. 43 0. 28 0. 28 0. 28  8..52 8..52 0.,20 0..18 0..00  0..60 0..86 0..56 0..56 0.,56  9..12 9..38 0..76 0..74 0..56  2  % Oxide i n unweathered m a t e r i a l T o t a l % oxide i n 11 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e % oxide Ammonium Oxalate e x t r a c t a b l e % o x i d e CBD e x t r a c t a b l e % oxide % B of A % E of A % t o t a l oxide removed (F + G)  M A S S I .  G R A N O D I O R I T E - %  TREATMENT Citric Oxalic Acetic HCL HOH I I .  B A S A L T %  Citric Oxalic Acetic HCL HOH A B C D E F G H  = = = = = = = =  B A L A N C E F e 0 2  B  5.21 5.21 5.21 5.21 5.21  2.37 4.68 0.57 0.34 0.11  0.37 5.72 0.11 0.14 0.31  4.,40 1..69 0..15 0..30 0..04  0.57 13 .44 0.06 0.13 0.03  2  B A T C H  E X P E R I M E N T  3  A  F e 0  C A L C U L A T I O N S  C  E  F  G  1. 43 2. 43 2. 06 1. 83 2. 00  0.72 2. 86 0.94 0.94 o. 72  45.49 89.83 10.94 6.52 2.11  13.81 54.89 18.04 18.04 13.82  59.70 144.70 28.98 24.56 15.93  1. 89 1. 89 4.58 3. 15 4.58  0.54 0.72 1. 00 1. 00 1. 07  35.31 13.56 1.21 2.40 0.32  4.33 5.78 8.02 8.02 8.59  39.64 19.34 9.22 10.42 8.91  D  H  3  12..46 12..46 12..46 12..46 12..46  % Oxide i n unweathered m a t e r i a l T o t a l % oxide i n 1 1 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e (% oxide) Ammonium Oxalate e x t r a c t a b l e (% oxide) CBD e x t r a c t a b l e (% oxide) % B of A % E Of A % t o t a l removed (F + G)  MASS B A L A N C E C A L C U L A T I O N S  I.  GRANODIORITE % A 1 0 2  TREATMENT Citric Oxalic Acetic HCL HOH II.  BASALT %  TREATMENT Citric Oxalic Acetic HCL HOH A B C D E F G H  = = — = = = = =  A  A1 0 2  EXPERIMENT  3  B  16.61 16.61 16.61 16.61 16.61  BATCH  1. 26 2. 63 0. 17 0.06 0.05  C 0.18 0.05 0.06 0.06 0.00  D 0.30 0.20 0.48 0.48 0.48  E  F  G  H  0.24 0.20 0.27 0.27 0.27  7.58 15.83 1.02 0.36 0.30  1.44 1.20 1.62 1.62 1.62  8.02 16.03 2.64 1.98 1.92  E  F  G  H  0.02 0.03 0.03 0.04  1.47 0.99 0.92 0.26  0.13 0.20 0.20 0.26  1.18 1.60 1.19 1.12 0.52  3  A 15.17 15.17 15.17 15.17 15.17  B 0.16 0.22 0.15 0.14 0.04  D  C 0.00 0.00 0.00 0.00 0.00  0.00 0.09 0.09 0.06 0.10  % Oxide i n unweathered m a t e r i a l T o t a l % o x i d e i n 11 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e % oxide Ammonium O x a l a t e e x t r a c t a b l e % oxide CBD e x t r a c t a b l e % oxide % B of A % E of A % t o t a l oxide removed (F + G)  M A S S I .  G R A N O D I O R I T E - % 8 i 0  TREATMENT  A % Si0  Citric Oxalic Acetic HCL HOH  63.80 63.80 63.80 63.80 63.80  I I . B A S A L T % -S i 0 Citric Oxalic Acetic HCL HOH A B C D E F G H  = = = = = = = =  B A L A N C E  49.96 49.96 49.96 49.96 49.96  C A L C U L A T I O N S  B A T C H  E X P E R I M E N T  2  B  C  0.97 1.83 0.16 0.05 0.03  0.38 0.62 0.00 0.00 0.00  5.80 3.79 0.18 0.15 0.04  0.75 0.75 0 0 0  E  F  G  0.00 0.00 0.00 0.00 0.00  0.32 0.48 0.16 0.16 0.11  1.52 2.86 1.56 0.08 0.05  0.50 0.75 0.25 0.25 0.17  2.02 3.61 1.81 0.33 0.22  0.26 0.43 1.63 0.94 1.63  0.43 0.60 0.54 0.21 0.54  11.62 7.59 0.37 0.30 0.08  0.86 1.20 1.08 0.43 1.08  12.48 8.79 1.45 0.73 1.16  D  H  2  2  % Oxide i n unweathered m a t e r i a l T o t a l % o x i d e i n 11 wks l e a c h a t e Pyrophoshate e x t r a c t a b l e (% oxide) Ammonium Oxalate e x t r a c t a b l e (% oxide) CBD e x t r a c t a b l e (% oxide) % B of A % E of A % t o t a l removed (F + G)  

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