Reconstructions of Three Cretaceous Marine Paleocommunities, Central Texas.
Mentor 1
Rex Hanger
Location
Union Wisconsin Room
Start Date
24-4-2015 2:30 PM
End Date
24-4-2015 3:45 PM
Description
The Early Cretaceous (Albian) Walnut Formation crops out in the low, wide valleys of the Lampasas Cut Plain of central Texas. The fauna is extremely fossiliferous, with faunas dominated by Bivalves, Gastropods, Cephalopods and Echinoids. New sampling localities are regularly revealed by home/business construction, due to the fact that the Killeen-Temple-Fort Hood Metropolitan Statistical Area (MSA) is one of the fastest growing MSA’s in the entire United States. Previous large collections of fossils from the Walnut Fm. were recently supplemented by newly discovered localities within the K-T-FH MSA, and three distinct paleocommunities were reconstructed from these data. Shallowest marine faunas at the base of the formation are low evenness, low richness, and dominated by the large gastropod, Peruviella dolium. These are replaced upwards in composite section by highest evenness, lowest richness biostromes of the bivalve oyster, Texigryphaea mucronata. The biostromes are highly resistant to weathering and form prominent exposed benches throughout the Walnut valleys. These biostromes are then replaced by the high evenness, highest richness fauna dominated by the oyster bivalves Exogyra texana and T. mucronata; many species of gastropods; the echinoid Enallaster texanum; and the ammonites Engonoceras pierdenale.and Oxytropidoceras salasi. Diversity characteristics of the three faunas are then used to create graphic reconstructions of the once-living organisms.
Reconstructions of Three Cretaceous Marine Paleocommunities, Central Texas.
Union Wisconsin Room
The Early Cretaceous (Albian) Walnut Formation crops out in the low, wide valleys of the Lampasas Cut Plain of central Texas. The fauna is extremely fossiliferous, with faunas dominated by Bivalves, Gastropods, Cephalopods and Echinoids. New sampling localities are regularly revealed by home/business construction, due to the fact that the Killeen-Temple-Fort Hood Metropolitan Statistical Area (MSA) is one of the fastest growing MSA’s in the entire United States. Previous large collections of fossils from the Walnut Fm. were recently supplemented by newly discovered localities within the K-T-FH MSA, and three distinct paleocommunities were reconstructed from these data. Shallowest marine faunas at the base of the formation are low evenness, low richness, and dominated by the large gastropod, Peruviella dolium. These are replaced upwards in composite section by highest evenness, lowest richness biostromes of the bivalve oyster, Texigryphaea mucronata. The biostromes are highly resistant to weathering and form prominent exposed benches throughout the Walnut valleys. These biostromes are then replaced by the high evenness, highest richness fauna dominated by the oyster bivalves Exogyra texana and T. mucronata; many species of gastropods; the echinoid Enallaster texanum; and the ammonites Engonoceras pierdenale.and Oxytropidoceras salasi. Diversity characteristics of the three faunas are then used to create graphic reconstructions of the once-living organisms.
