Geochemical sampling strategies for discovering buried copper porphyries, Atacama Desert, Chile
department or school: Science, Faculty of
department or school: Earth, Ocean and Atmospheric Sciences, Department of
data provider: DSpace
degree campus: UBCV
creator: Brown, Alexandra E.
issued: 2019-11-30T08:00:00+0000
issued: 2018
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Several of the world’s largest porphyry copper deposits are found in the hyper-arid Atacama Desert of Chile, yet discovery of new deposits has become increasingly challenging due to the thick gravel cover. The Atlántida porphyry copper deposit, Atacama Region, Chile, is buried under 25-80m of Neogene-Quaternary gravel and 200m of barren to low-grade bedrock. Geochemical sampling occurred over two phases to develop sampling techniques to detect buried mineralization through the gravels. Over the two phases, physicochemical measurements were recorded at each site, and AGI GoresorberTM hydrocarbon collectors were installed. Sample lines extended into background and over mineralization, staying within consistent background chemistry. Phase I samples were collected with 50m spacing. Soil samples were analyzed by Aqua Regia (Phase I) and deionized water extraction with ICP-MS (Phase I and II). Phase I deionized water extraction results indicated elevated concentrations of Mo, Re, Se, As with increasing salinity. Anomalous responses occur spatially correlated with structures on the surface, and in close proximity to highly saline pockets of material (median 2.2% salt) identified through remote sensing used in Phase II regolith mapping. Saline pocket material was formed by seismically induced surface flooding of groundwater along faults extending to surface. Phase II sampled only saline pockets oriented along structural extent at 250m spacing. Samples (n=9) were analyzed for copper isotope composition over buried mineralization by partial digestion. Isotopic results indicate copper concentrations by partial extraction are dominantly a reflection of endogenic material. Both hydrocarbon and soil extraction results show strong structural control on anomaly formation at the surface. Strong correlations of increasing salinity and metals/metalloids (Mo, Re, Se, and Te) concentrations are observed. Elevated responses of these metals normalized to groundwater volume proxy occur dir…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/67824
note: GEOCHEMICAL SAMPLING STRATEGIES FOR DISCOVERING BURIED COPPER PORPHYRIES, ATACAMA DESERT, CHILEby Alexandra E. Brown B.Sc.H, Queen’s University, 2013 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE inTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Geological Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) November, 2018 © Alexandra E. Brown, 2018iiCommittee pageThe following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis/dissertation entitled:Geochemical Sampling Strategies for Discovering Buried Copper Porphyries, Atacama Desert, Chilesubmitted by Alexandra Brown in partial fulfillment of the requirements forthe degree of Master of Science in Geological Sciences Examining Committee:Dr. Peter Winterburn Supervisor Dr. Thomas Bissig Supervisory Committee Member Dr. Gregory Dipple Supervisory Committee MemberDr. Craig Hart Additional Examiner Additional Supervisory Committee Members:Dr. Roger Beckie Supervisory Committee MemberiiiAbstract Several of the world’s largest porphyry copper deposits are found in the hyper-arid Atacama Desert of Chile, yet discovery of new deposits has become increasingly challenging due to the thick gravel cover. The Atlántida porphyry copper deposit, Atacama Region, Chile, is buried under 25-80m of Neogene-Quaternary gravel and 200m of barren to low-grade bedrock. Geochemical sampling occurred over two phases to develop sampling techniques to detect buried mineralization through the gravels. Over the two phases, physicochemical measurements were recorded at each site, and AGI GoresorberTM hydrocarbon collectors were installed. Sample lines extended into background and over mineralization, staying within consistent background chemistry. Phase I samples were collected with 50m spacing. Soil samples were analyzed by Aqua Regia (Phase I) and deionized water extrac-tion with ICP-MS (Phase I and II). P…
has type: Thesis/Dissertation
date issued: 2019-02
is shown at: 10.14288/1.0374148
language: eng
degree discipline: Geological Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/67824