Thesis
Constraining the origin and evolution of the basement rocks in the Raft River, Albion, Grouse Creek core complex, Northwestern Utah and southern Idaho
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/100742
Abstract
Metamorphic core complexes are found in mountain belts around the world and provide an opportunity to examine exposures of lower crustal rocks within areas that have undergone large-scale contraction and ensuing extension. Examinations of these basement rocks provide a glimpse into some of the earliest stages of continental growth. The Raft River-Albion-Grouse Creek core complex represents some of the westernmost documented exposures of Archean basement rock in North America. The chronology of the basement geology is complex and currently not well constrained. Here new LA-ICP-MS (Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry) U/Pb zircon age data is presented for the metasedimentary (schist) and plutonic rocks (monzogranite and trondhjemite) that are thought to represent the oldest portions of the Raft River-Albion-Grouse Creek core complex. The LA-ICP-MS yielded maximum depositional 207Pb/206Pb ages of ca. 2649 Ma and 2692 Ma for the schists. Zircons analyzed from monzogranite samples confirm a Late Archean component with 207Pb/206Pb ages between ca. 2571 Ma and 2585 Ma, but also show evidence for a Late Cretaceous metamorphic event and magmatic intrusion ca. 95 Ma. The trondhjemite samples yielded a variety of dominant age groups of ca. 2683 Ma, 1863 Ma, 95 Ma and 82 Ma. The schist is interpreted to be the oldest portion of the complex that likely represents a passive margin of paleo-North America from ca. 2649 Ma to ca. 2592 Ma. The upper monzogranite ages provide a minimum depositional age for the schist. Combined evidence indicates the possibility of multiple, previously undiscovered, igneous intrusions into the eastern Raft River Range during the Late Cretaceous.
Metrics
13 File views/ downloads
15 Record Views
Details
- Title
- Constraining the origin and evolution of the basement rocks in the Raft River, Albion, Grouse Creek core complex, Northwestern Utah and southern Idaho
- Creators
- Vincent H. Isakson
- Contributors
- Jeffrey D. Vervoort (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525196701842
- Language
- English
- Resource Type
- Thesis