A Complex Interplay Between Pluton Emplacement, Tectonic Deformation, and Plate Kinematics in the Cretaceous Sierra Nevada Magmatic Arc, California

0584023 - GLÚ 2025 RIV US eng J - Článek v odborném periodiku
Tomek, Filip - Žák, J. - Verner, K. - Ježek, J. - Paterson, S. R.
A Complex Interplay Between Pluton Emplacement, Tectonic Deformation, and Plate Kinematics in the Cretaceous Sierra Nevada Magmatic Arc, California.
Tectonics. Roč. 43, č. 3 (2024), č. článku e2023TC007822. ISSN 0278-7407. E-ISSN 1944-9194
Grant ostatní: AV ČR(CZ) MSM100131601
Program: Program na podporu mezinárodní spolupráce začínajících výzkumných pracovníků
Institucionální podpora: RVO:67985831
Klíčová slova: anisotropy of magnetic susceptibility (AMS) * magmatic arc * transpression * plate convergence * pluton emplacement * strain partitioning * Tuolumne intrusive complex
Obor OECD: Geology
Impakt faktor: 4.2, rok: 2022
Způsob publikování: Open access
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023TC007822

The relation of plate kinematics to the structural record of arc plutons and their host rocks is complex and still not fully understood. We address this issue through a combination of field mapping, structural analysis, anisotropy of magnetic susceptibility analysis, and fabric modeling in the Late Cretaceous Tuolumne Intrusive Complex, Sierra Nevada, California. A pattern of anti-clockwise rotation from ∼NNW–SSE to WNW–ESE steep foliations and change in fabric ellipsoid shape from oblate to prolate was revealed in successively emplaced Kuna Crest (∼95–92 Ma), Half Dome (∼92–89 Ma), and Cathedral Peak (∼89–84 Ma) granodiorites. The numerical model indicates that the Kuna Crest was emplaced in a transpressional setting with an angle of convergence α = 60–40°, whereas the Half Dome and Cathedral Peak required simultaneous vertical constriction overprinted by transpression with α = 35–15°. This transition, which occurred at ∼92 Ma, is accompanied by a shallowing of the lineation plunge observed also in other ∼88–84 Ma central Sierra Nevada plutons. Provided that the Cretaceous Sierra Nevada arc was constructed during overall dextral transpression, these transitions reflect significant changes in kinematics, where ∼107–92 Ma plutons were emplaced during pure shear-dominated transpression, which was followed by a transition to wrench-dominated transpression recorded in ∼92–84 Ma plutons. Such a transition in kinematics is explained as a result of progressively increasing obliquity of the relative convergence of the Farallon plate subducting beneath the North American continental margin, in agreement with most paleogeographic reconstructions.
Trvalý link: https://hdl.handle.net/11104/0352017