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Collapse of southwestern North America and the evolution of early Miocene detachment faults, metamorphic core complexes, the Sierra Nevada orocline, and the San Andreas fault system

1995; Geological Society of America; Volume: 23; Issue: 12 Linguagem: Inglês

10.1130/0091-7613(1995)023 2.3.co;2

1943-2682

Roy K. Dokka, Timothy M. Ross,

Geology and Paleoclimatology Research

Research Article| December 01, 1995 Collapse of southwestern North America and the evolution of early Miocene detachment faults, metamorphic core complexes, the Sierra Nevada orocline, and the San Andreas fault system Roy K. Dokka; Roy K. Dokka 1Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar Timothy M. Ross Timothy M. Ross 1Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 708032Department of Geological Sciences, California State University, San Bernardino, California 92407 Search for other works by this author on: GSW Google Scholar Author and Article Information Roy K. Dokka 1Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803 Timothy M. Ross 1Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 708032Department of Geological Sciences, California State University, San Bernardino, California 92407 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (12): 1075–1078. https://doi.org/10.1130/0091-7613(1995)023 2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Roy K. Dokka, Timothy M. Ross; Collapse of southwestern North America and the evolution of early Miocene detachment faults, metamorphic core complexes, the Sierra Nevada orocline, and the San Andreas fault system. Geology 1995;; 23 (12): 1075–1078. doi: https://doi.org/10.1130/0091-7613(1995)023 2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Plate reconstructions indicate that early Miocene Pacific–North American relative motion was not parallel to the transform, but was instead oblique and transtensional. We propose that the western edge of the North American plate east of the transform gravitationally collapsed to the southwest in response to this divergence. The northern and eastern edges of the collapsed region underwent extension between 24 and 20 Ma. Whereas extension in southeastern California and southern Arizona during this interval was coaxial with the overall S50°–60°W collapse direction, the extension direction along the northern oundary (Mojave extensional belt) was north-south and the result of the combined effects of the southwestward collapse and the independent northwestward translation of the region to the north. Collapse continued between 20 and 16 Ma, and extension persisted in southeastern California and southern Arizona; extension along the northern boundary waned owing to the apparent cessation of motion of the region to the north. Thus, the kinematics of the northern boundary changed to dextral shear and extension along what is here named the "Trans–Mojave-Sierran shear zone." This east-west zone of mainly right shear oroclinally folded the southern tail of the Sierra Nevada and the central Mojave Desert; rocks within this 83–110-km-wide zone were rotated (Approx.)40°–60° (clockwise) about vertical axes. Finally, as collapse moved the North American plate progressively west across the locus of transform shear, its western edge became increasingly subject to the motion of the Pacific plate. Over time, the edge of North America was truncated by faults of the San Andreas system and transferred to the Pacific plate. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.