T303 The Timing and Causes of Jurassic–Cretaceous Biological, Climatic, and Tectonic Transitions in North America

Wednesday, 25 October 2017
8:00 AM - 12:00 PM
Room 611

DIAGENESIS OF VERTEBRATE SKELETAL REMAINS OF THE CRETACEOUS KAIPAROWITS FORMATION AND THEIR USE AS PALEOHYDROLOGIC PROXIES: A COMPLEX HYDROLOGIC SETTING

Paper number: T303-3
Program: Technical Sessions
Time: 8:30 AM – 8:45 AM

Authors

Abstract

The Kaiparowits Formation is a rapidly deposited fluvial-coastal plain deposit and preserves one of the most complete fossil records of the Campanian (late Cretaceous) North America. Such a unique deposit provides an opportunity to investigate the interaction between physical environment and paleoecology. As a part of paleoclimatic investigation, stable isotope compositions of vertebrate skeletal remains were analyzed. The oxygen isotope compositions of structural (δ18Oc) and phosphate (δ18Op) do not exhibit the equilibrium relationship observed in modern mammal bone, suggesting potential diagenetic alteration to one or both oxygen components. However, average δ18Oc from each taxon show the same trend as the δ18Op stratigraphic change, suggesting potential use of δ18Oc as a paleoclimatic proxy. Previous study indicates influence of the Western Interior Seaway at 300m from the base and δ18Op of turtle and crocodile are supportive of this trend. Compared to other Campanian formations, fossil δ18Op are depleted for their paleolatitude, suggesting the Kaiparowits Plateau had higher input from high-elevation runoff, consistent with other paleoclimatic studies. Estimated δ18Ow ranged between vadose influenced dry season values of -8.88‰ to high elevation runoff values of -13.76‰ suggesting dynamic hydrologic interactions.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-295096

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