14th Symposium on Mesozoic Terrestrial Ecosystems and Biota

Terrestrial deposits, including paleosols, contain an abundance of paleoclimate and paleoenvironmental data. Chemical, mineralogical, and stable isotopic proxies that have been developed to study paleosols can be applied to the geologic record to answer questions regarding the interaction between climatic, biotic, and atmospheric processes. For example, the δ, C of C, plant organic matter is thought to be driven by isotopic composition of atmospheric CO, and climatic conditions, in particular mean annual precipitation. The magnitude in which these factors influence the δ, C of plant organic matter is still debated and few studies have analyzed these relationships in deep geologic time. In this study multiple stable isotope proxies including analyses of pedogenic carbonate and pedogenic phyllosilicates are used to reconstruct paleoclimatic and paleoatmospheric conditions during the Mid-Cretaceous (Aptian-Cenomanian) using terrestrial deposits in north-central Texas and southern Oklahoma. These results in conjunction with analyses of the δ, C of plant organic material at each locality were then compared. Samples were collected from 5 localities: the Proctor Lake (PL) and Jones Ranch (JR) localities from the Twin Mountains Formation (Aptian/Albian); the Cross locality (CR) from the Antlers Formation (Albian); and the Arlington Archosaur Site (AAS) and Acme Brick Pit locality (ABP) from the Woodbine Group (Cenomanian).