2009 Portland GSA Annual Meeting (18-21 October 2009)

Paper No. 10
Presentation Time: 9:00 AM-6:00 PM

CHONDRICHTHYANS FROM THE LOWER FERRON SANDSTONE MEMBER OF THE MANCOS SHALE (UPPER CRETACEOUS: MIDDLE TURONIAN) OF EMERY AND CARBON COUNTIES, UTAH, USA


BECKER, Martin A.1, WELLNER, Robert W.2, MALLERY Jr, Christopher S.1 and CHAMBERLAIN Jr, John A.3, (1)Department of Environmental Science, William Paterson University, Wayne, NJ 07470, (2)ExxonMobil Development Company, 12450 Greenspoint Drive, Houston, TX 77066, (3)Department of Earth and Environmental Sciences, Brooklyn College, and Doctoral Programs in Earth and Environmental Sciences and Biology, CUNY Graduate Center, New York, NY 10016, beckerm2@wpunj.edu

The Lower Ferron Sandstone Member of the Mancos Shale in southeastern Utah preserves a chondrichthyan assemblage of at least 13 taxa that include: Hybodus sp., Ptychodus cf. P. mammillaris Agassiz, 1843, Ptychodus whipplei Marcou, 1858, cf. Chiloscyllium sp., Scapanorhynchus raphiodon (Agassiz, 1843), Cretodus crassidens (Dixon, 1850), cf. Leptostyrax sp., cf. Cretalamna appendiculata (Agassiz, 1835), Squalicorax sp., Pseudohypolophus mcnultyi (Thurmond, 1971), Protoplatyrhina hopii Williamson, Kirkland and Lucas, 1993, Ischyrhiza schneideri (Slaughter and Steiner, 1968), and Ptychotrygon triangularis (Reuss, 1844). Although this assemblage is typical of other Turonian chondrichthyan faunas in North America, fossil teeth are preserved in two unique facies associations that consist of arenitic sandstones with mud interclasts and rounded chert, feldspar and quartz pebbles. The coarser beds within these facies associations are previously interpreted to represent storm events and turbidity flows associated with a sea level lowstand. Chondrichthyan teeth occurring within these coarser beds are indicative of extensive transport and reworking and attest to the durable nature of chondrichtyan teeth for biostratigraphic and paleoecological interpretations. Similar studies of chondrichthyan teeth in shelf marine settings may also provide new insights for facies interpretations related to sequence stratigraphy and regional stratigraphic correlations.