Evaluating local and extraregional sources for the Late Cretaceous Nanaimo Group, British Columbia, via coupled detrital K-feldspar 40Ar/39Ar thermochronology and Pb isotopes
Abstract/Contents
- Abstract
- The Nanaimo Group of southwestern British Columbia has been the source of significant scientific interest due to its relationship with the Baja British Columbia (Baja BC) hypothesis -- the idea that the Nanaimo Group, along with much of western British Columbia, was originally located 2000--4000 km south of its present location on the western North American margin. My Ph.D. research uses 40Ar/39Ar thermochronology and Pb isotope analysis of detrital K-feldspar to examine the provenance of the Nanaimo Group's sandstones. I test connections to its local detritus source -- the Coast Mountains batholith of British Columbia -- and the two most likely extraregional sources -- the Idaho batholith and Mojave batholith. In Chapter 1, I analyze the 40Ar/39Ar cooling history of detrital K-feldspar from various sedimentary formations of the Nanaimo Group and compare it to a database of over 2,400 biotite 40Ar/39Ar and K/Ar cooling ages compiled from predominantly Cretaceous batholiths along the western North American margin. In Chapter 2, I examine basement K-feldspar Pb isotope values from samples collected throughout the Pacific Northwest and integrate them into a compiled database of 700 basement K-feldspar and 1415 age-corrected whole rock samples in western North America. In Chapter 3, I compare the Pb isotopic composition of detrital K-feldspar from the Nanaimo Group to western North America's basement rocks in order to identify (or rule out) extraregional sediment sources for the Nanaimo basin. While the western Idaho batholith yields the closest match of 40Ar/39Ar and Pb results to those of the Nanaimo Group, neither it nor the Mojave batholith fully accounts for all geochemical signatures found in the Nanaimo basin's extraregionally-sourced sedimentary formations.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Isava, Virginia |
|---|---|
| Degree supervisor | Grove, Marty, 1958- |
| Thesis advisor | Grove, Marty, 1958- |
| Thesis advisor | Caers, Jef |
| Thesis advisor | Mahoney, Brian J |
| Degree committee member | Caers, Jef |
| Degree committee member | Mahoney, Brian J |
| Associated with | Stanford University, Department of Geological Sciences |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Virginia Isava. |
|---|---|
| Note | Submitted to the Department of Geological Sciences. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/gg875tt3417 |
Access conditions
- Copyright
- © 2021 by Virginia Isava
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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