A PALEOECOLOGIC ASSESSMENT OF THE FREDERICKSBURG GROUP EXPOSURE IN OGLESBY, TEXAS

The Comanche Peak Limestone is an Early Cretaceous formation, part of the Albian-aged Fredericksburg Group. The Fredericksburg rocks record the advancement of the Western Interior Seaway and stand as a classic example of a transgressive sequence (Ewing, 2016). The Comanche Peak Limestone is highly fossiliferous and predominantly consists of shallow marine deposits, characterized by heavy bioturbation, marls, and chalky limestones (Hill, 1937). While the Fredericksburg Group has been extensively studied since the late 1800’s, modern research has neglected the Comanche Peak in favor of the overlying Edwards Limestone. The Edwards is a rudistid framestone, significant for its petroleum and aquifer properties. An exposure in Oglesby, Texas, comprises approximately 6.5 feet of Walnut Formation, 45 feet of Comanche Peak Limestone, and approximately 15 feet of Edwards Limestone. The association of three formations in one locality, combined with the abundance of fossil material, makes it a valuable candidate for studying paleoecological succession over time in one location. This study seeks to contribute, to a small degree, a more complete understanding of the Comanche Peak Limestone and the Fredericksburg Group as whole.