Integrated Examination of Petrology, Diagenesis, and Depositional Environment of the Catahoula Formation in Jasper County, Texas
Gregory J. Anderson
Austin State University
The Catahoula Formation in Jasper County, Texas consists of channel, floodplain, crevasse splay and lacustrine sandstones and mudstones deposited onto the Texas Gulf Coast Plain from the mid-Oligocene through early-Miocene. Through field investigation, optical microscopy of thin sections, XRPD of the clay sized fraction, and SEM, this study examines the petrology, diagenetic history, and depositional environment of the Catahoula Formation in Jasper County, Texas.
Sandstones are dominantly mature medium-fine grained sub-litharenites. Petrographic examination indicates that sediments originated from multiple sources. High amounts of volcanic rock fragments, in the form of vitric air-fall tephra, are present throughout the study area. Devitrification of volcanic tephra, as well as the dissolution of feldspars, represents the primary sources of authigenic montmorillonite, kaolinite and opal-CT cements present. The lack of illite, absence of quartz overgrowths or solution contacts between grains, and the presence of opal-CT as cement indicates that sediments were never buried to significant depth during diagenesis. Meteoric groundwater is the primary agent of change within beds. Interbedded floodplain deposits have restricted the circulation of meteoric waters resulting in lateral and vertical variability in diagenetic alterations.
AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013