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Depositional history of an Upper Triassic drowned carbonate platform sequence: Wallowa terrane, Oregon and Idaho

1988; Geological Society of America; Volume: 100; Issue: 7 Linguagem: Inglês

10.1130/0016-7606(1988)100 2.3.co;2

1943-2674

Michael T. Whalen,

Water Quality and Resources Studies

Research Article| July 01, 1988 Depositional history of an Upper Triassic drowned carbonate platform sequence: Wallowa terrane, Oregon and Idaho MICHAEL T. WHALEN MICHAEL T. WHALEN 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244-1070 Search for other works by this author on: GSW Google Scholar Author and Article Information MICHAEL T. WHALEN 1Department of Geology, Heroy Geology Laboratory, Syracuse University, Syracuse, New York 13244-1070 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1988) 100 (7): 1097–1110. https://doi.org/10.1130/0016-7606(1988)100 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 MICHAEL T. WHALEN; Depositional history of an Upper Triassic drowned carbonate platform sequence: Wallowa terrane, Oregon and Idaho. GSA Bulletin 1988;; 100 (7): 1097–1110. doi: https://doi.org/10.1130/0016-7606(1988)100 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 The Upper Triassic Martin Bridge Limestone exposed in Hells Canyon, along the Idaho-Oregon border, is a thick sequence of limestone and dolostone. The allochthonous nature and low-latitude origin of the Martin Bridge and underlying Seven Devils Group, which along with coeval rocks exposed in the Wallowa Mountains, make up the Wallowa terrane, are well established. The Martin Bridge Limestone in Hells Canyon was deposited initially under supratidal and intertidal conditions and then in a shallow subtidal environment. Absence of terrigenous or volcanic sediments indicates that these carbonates were isolated from a source of such sediment. Although potential reef-building organisms are present in the Martin Bridge Limestone, no reef structures are exposed in Hells Canyon. The shelf-edge environment apparently was dominated by relatively coarse grainstone and packstone shoals and banks. Stratigraphic evidence from the Wallowa Mountains and near Riggins, Idaho, indicates that the Martin Bridge carbonate platform was eventually drowned and overlain by fine-grained argillaceous and siliceous clastic sediments. Decreased benthic carbonate production, due to climatic deterioration initiated by northward drift, and increased clastic and volcaniclastic input, from adjacent terranes and the Wallowa terrane itself, facilitated drowning of the carbonate platform. 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.