The uplift of the Sierra Nevada and implications for late Cenozoic epeirogeny in the western Cordillera

Abstract

Research Article| November 01, 1991 The uplift of the Sierra Nevada and implications for late Cenozoic epeirogeny in the western Cordillera J. R. UNRUH J. R. UNRUH 1Department of Geology, University of California, Davis, California 95616 Search for other works by this author on: GSW Google Scholar Author and Article Information J. R. UNRUH 1Department of Geology, University of California, Davis, California 95616 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1991) 103 (11): 1395–1404. https://doi.org/10.1130/0016-7606(1991)103<1395:TUOTSN>2.3.CO;2 Article history First Online: 01 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 J. R. UNRUH; The uplift of the Sierra Nevada and implications for late Cenozoic epeirogeny in the western Cordillera. GSA Bulletin 1991;; 103 (11): 1395–1404. doi: https://doi.org/10.1130/0016-7606(1991)103<1395:TUOTSN>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 SocietyGSA Bulletin Search Advanced Search Abstract Tilted Cenozoic strata in the eastern Great Valley, California, record progressive late Cenozoic uplift of the Sierra Nevada. The magnitude of tilting is combined with other geologic data, using a technique pioneered by Grant and others, to infer the rate and timing of post-late Miocene uplift between the Kings River and the Feather River.Angular unconformities of late Neogene age have been reported throughout the east-central Great Valley. Typically, stratigraphic units of late Oligocene through Miocene-Pliocene age beneath the unconformities dip approximately 1.2°-1.6° southwest. Middle to late Pliocene units above the unconformities dip approximately 0.6°-0.9° southwest and progressively overlap younger units from east to west. These angular unconformities are interpreted to represent the onset of late Cenozoic uplift of the Sierra Nevada due to westward tilting. Dated volcaniclastic units in the east-central Sacramento Valley bracket the onset of tilting there between 3.4 and 8.4 Ma. Stratigraphic and geologic relations from the Stanislaus River area, eastern San Joa-quin Valley, suggest that the late Cenozoic tilting probably began approximately 5 Ma.Previously published tilt data from the San Joaquin Valley combined with new work in the eastern Sacramento Valley indicate that the rate of post-late Miocene tilting has been approximately uniform in the east-central Great Valley. Early to middle Pleistocene units typically dip 0.5°-0.7° southwest; middle Pleistocene units dip 0.2°-0.4°; middle to late Pleistocene units dip 0.1°-0.15°; late Pleistocene units dip 0.05°-0.1°. If it is assumed that major westward tilting began 5 Ma, these data indicate an approximately uniform tilting rate of 0.28° per million years.These data have important implications for models of the uplift. Simultaneous inception of tilting in the east-central Great Valley at approximately 5 Ma does not support models that link uplift of the Sierra Nevada to the migration of the Mendocino triple junction. Late Cenozoic tilting of the Sierra Nevada block does not appear to coincide temporally with the onset of major Basin and Range extension. The uplift may be due to thinning of the mantle lithosphere beneath the Sierra Nevada, but the tilt data do not afford a direct test of this hypothesis.Post-late Miocene tilting of the Sierra Nevada is temporally associated with late Cenozoic uplift of the northern Basin and Range, uplift of the Cascades, uplift of the Colorado Plateau, and uplift of the southern Rocky Mountains, supporting the contention that tilting of the Sierra Nevada may have occurred as part of a Cordillera-wide uplift event. 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.