Position of the Triassic–Jurassic boundary and timing of the end-Triassic extinctions on land: Data from the Moenave Formation on the southern Colorado Plateau, USA

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew B. Heckert Ph.D., Professor (Creator)
Institution
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/

Abstract: Strata of the Moenave Formation on and adjacent to the southern Colorado Plateau in Utah–Arizona, U.S.A., represent one of the best known and most stratigraphically continuous, complete and fossiliferous terrestrial sections across the Triassic–Jurassic boundary. We present a synthesis of new biostratigraphic and magnetostratigraphic data collected from across the Moenave Formation outcrop belt, which extends from the St. George area in southwestern Utah to the Tuba City area in northern Arizona. These data include palynomorphs, conchostracans and vertebrate fossils (including footprints) and a composite polarity record based on four overlapping magnetostratigraphic sections. Placement of the Triassic–Jurassic boundary in strata of the Moenave Formation has long been imprecise and debatable, but these new data (especially the conchostracans) allow us to place the Triassic–Jurassic boundary relatively precisely in the middle part of the Whitmore Point Member of the Moenave Formation, stratigraphically well above the highest occurrence of crurotarsan body fossils or footprints. Correlation to marine sections based on this placement indicates that major terrestrial vertebrate extinctions preceded marine extinctions across the Triassic–Jurassic boundary and therefore were likely unrelated to the Central Atlantic Magmatic Province (CAMP) volcanism.

Additional Information

Publication
A.B. Heckert, S.G. Lucas, L.H. Tanner, L.L. Donohoo-Hurley, J.W. Geissman, H.W. Kozur, R.E. Weems (2011) "Position of the Triassic–Jurassic boundary and timing of the end-Triassic extinctions on land: Data from the Moenave Formation on the southern Colorado Plateau, USA" Palaeogeography, Palaeoclimatology, Palaeoecology volume 201 pp. 194-205 [doi:10.1016/j.palaeo.2011.01.009] Version of Record Available From (www.sciencedirect.com)
Language: English
Date: 2011
Keywords
Triassic, Jurassic, Mass extinction, Moenave Formation, Nonmarine Triassic–Jurassic boundary

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