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Stratigraphy and depositional environments of the upper Fox Hills and lower Hell Creek Formations at the Concordia Hadrosaur Site in northwestern South Dakota

2004; University of Wyoming; Volume: 39; Issue: 2 Linguagem: Inglês

10.2113/39.2.93

0010-7980

Mary Colson, R. O. Colson, Ron Nellermoe,

Paleontology and Stratigraphy of Fossils

Research Article| January 01, 2004 Stratigraphy and depositional environments of the upper Fox Hills and lower Hell Creek Formations at the Concordia Hadrosaur Site in northwestern South Dakota Mary C. Colson; Mary C. Colson 1Moorhead Junior High, Moorhead, MN 56560, U.S.A. Search for other works by this author on: GSW Google Scholar Russell O. Colson; Russell O. Colson * 2Department of Anthropology and Earth Science, Minnesota State University Moorhead, Moorhead, MN 56563, U.S.A. *Author to whom correspondence should be addressed. colson@mnstate.edu Search for other works by this author on: GSW Google Scholar Ron Nellermoe Ron Nellermoe 3Department of Biology, Concordia College, Moorhead, MN 56560, U.S.A. Search for other works by this author on: GSW Google Scholar Author and Article Information Mary C. Colson 1Moorhead Junior High, Moorhead, MN 56560, U.S.A. Russell O. Colson * 2Department of Anthropology and Earth Science, Minnesota State University Moorhead, Moorhead, MN 56563, U.S.A. Ron Nellermoe 3Department of Biology, Concordia College, Moorhead, MN 56560, U.S.A. *Author to whom correspondence should be addressed. colson@mnstate.edu Publisher: University of Wyoming Received: 30 May 2003 Revision Received: 18 Mar 2004 Revision Received: 27 May 2004 Accepted: 29 Oct 2004 First Online: 03 Mar 2017 Online Issn: 1555-7340 Print Issn: 1555-7332 UW Department of Geology and Geophysics Rocky Mountain Geology (2004) 39 (2): 93–111. https://doi.org/10.2113/39.2.93 Article history Received: 30 May 2003 Revision Received: 18 Mar 2004 Revision Received: 27 May 2004 Accepted: 29 Oct 2004 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Mary C. Colson, Russell O. Colson, Ron Nellermoe; Stratigraphy and depositional environments of the upper Fox Hills and lower Hell Creek Formations at the Concordia Hadrosaur Site in northwestern South Dakota. Rocky Mountain Geology 2004;; 39 (2): 93–111. doi: https://doi.org/10.2113/39.2.93 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 SocietyRocky Mountain Geology Search Advanced Search Abstract Many of the dinosaur-bearing bone beds in the Hell Creek Formation of the Dakotas and Montana involve multiple species preserved in the upper Hell Creek Formation. In contrast, the Concordia Hadrosaur Site is monospecific with respect to dinosaurian taxa and is situated in the lower Hell Creek Formation in a lithostratigraphic unit we associate with the Little Beaver Creek Member. This member consists of organic-rich sandstones, siltstones, and claystones that are distinctive within the Hell Creek Formation based on their uniformly fine grain size, purplish color, and presence of highly lignitic shale rather than coal. Similar lignitic deposits occur at other marine-terrestrial boundaries of the Fox Hills-Hell Creek Formations in the Little Missouri and Missouri River valleys.The bone bed at the Concordia Hadrosaur Site (CHS) is associated with an extensive coastal swamp rather than a localized fluvial subenvironment such as river channel, floodplain, or abandoned channel. The bone bed itself lies at the transition from an extensive swamp (represented by highly organic mudstones) to a more fluvially dominated, distributary environment characterized by variegated mudstones, siltstones, and channel sandstones.The thirty meters of exposed section at the Concordia site include the top of the Fox Hills Formation and lower parts of the Hell Creek Formation. We identify marine silts, muds, and sands, coastal dune sands, coastal swamp muds and silts, and fluvial sands and silts. The sediments are indicative of the marine-terrestrial transition from upper shoreface and foreshore environments to a complex system of coastal dunes, swamps, and distributary channels that formed during the progradation of the Hell Creek sediments into the Cretaceous Fox Hills seaway. Locally, grain size and organic fraction varied due to differences in the proximity to distributary channels, supply of organic material, and water depth.Despite the concentration of bones dominated by a single species in the CHS bone bed, the high clay fraction of the bone bed matrix, combined with the fact that the lowest part of the bone bed has the greatest clay fraction, indicates that the bones were not introduced by way of a high-energy, catastrophic event, such as a flood. Rather, the bones accumulated in an area of quiet standing water. Although preliminary examination of the bones is consistent with this depositional interpretation, it does not necessarily provide direct support for it. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.