The Cordilleran lithosphere beneath south-central British Columbia : insights from two xenolith suites
department or school: Science, Faculty of
department or school: Earth, Ocean and Atmospheric Sciences, Department of
data provider: DSpace
degree campus: UBCV
creator: Kroner, Ryan Keith
issued: 2019-07-04T19:45:25Z
issued: 2019
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Mantle-derived peridotite xenoliths represent a valuable source of information about the structure, chemistry, origin, and evolution of the mantle lithosphere underlying various tectonic environments. Xenolith-bearing volcanic suites at Mt. Timothy and Summit Lake in south-central British Columbia are two particularly intriguing sites for evaluating the nature of the lithosphere beneath the southern Canadian Cordillera. The peridotite xenoliths at Mt. Timothy are texturally and mineralogically homogenous, while the xenoliths from Summit Lake contain a greater variety of textures and rock types, both mantle-derived and crustal. These peridotites are similar geochemically to other peridotite datasets from the Canadian Cordillera, indicating a geochemically homogenous mantle lithosphere and evolution from a fertile peridotite source. Enrichments of MREEs and LREEs in certain samples may indicate that these rocks were subject to a small degree of metasomatism. The geochemical signatures of the pyroxenes in these xenoliths are indicative of an orogenic lithospheric mantle. Temperatures and depths of equilibration for these peridotites have been determined by combining a two-pyroxene geothermometer with a geotherm constructed from several regional geophysical parameters. The Mt. Timothy peridotites sample an extensive window of mantle lithosphere ranging from the Moho (813 °C; 33 km) to relatively deep within the mantle lithosphere (1091 °C; 50.9 km), while the Summit Lake peridotites sample a very deep and narrow window of mantle lithosphere (1061 °C to 1119 °C; 49.0 km to 52.7 km). The window sampled by Mt. Timothy is most similar to a number of other xenolith suites scattered across the southern Cordillera, while the comparatively unique sampling range of the Summit Lake suite shares certain mineralogical characteristics with other xenolith suites straddling the boundary between the Cordillera and the North American craton.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/70916
note: THE CORDILLERAN LITHOSPHERE IN SOUTH-CENTRAL BRITISH COLUMBIA: INSIGHTS FROM TWO XENOLITH SUITES by Ryan Keith Kroner B.A., Colorado College, 2016 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Geological Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) June 2019 © Ryan Keith Kroner, 2019 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis/dissertation entitled: The Cordilleran lithosphere beneath south-central British Columbia: insights from two xenolith suites submitted by Ryan Kroner in partial fulfillment of the requirements for the degree of Master of Science in Geological Sciences Examining Committee: James Kelly Russell, Geological Sciences Supervisor Maya Kopylova, Geological Sciences Supervisory Committee Member Lori Kennedy, Geological Sciences Supervisory Committee Member Lee Groat, Geological Sciences Additional Examiner iii ABSTRACT Mantle-derived peridotite xenoliths represent a valuable source of information about the structure, chemistry, origin, and evolution of the mantle lithosphere underlying various tectonic environments. Xenolith-bearing volcanic suites at Mt. Timothy and Summit Lake in south-central British Columbia are two particularly intriguing sites for evaluating the nature of the lithosphere beneath the southern Canadian Cordillera. The peridotite xenoliths at Mt. Timothy are texturally and mineralogically homogenous, while the xenoliths from Summit Lake contain a greater variety of textures and rock types, both mantle-derived and crustal. These peridotites are similar geochemically to other peridotite datasets from the Canadian Cordillera, indicating a geochemically homogenous mantle lithosphere and evolution from a fertile peridotite source. Enrichments of MREEs and LREEs in certain samples may indicate that these rocks were subje…
has type: Thesis/Dissertation
date issued: 2019-09
is shown at: 10.14288/1.0379760
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/2429/70916