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Geochemistry of the Haynesville Formation Using the Carthage Core in Panola County, Texas


The Haynesville Formation has been described as a fine grained, organic, homogeneous shale that was deposited during the warm upper Jurassic (Kimmeridgian) in the tectonically formed East Texas Basin (Mainali, 2011). The Late Jurassic is characterized by a world-wide transgression that flooded most of the Atlantic shelves, followed by a regression (Hammes and Frebourg, 2011). The Haynesville Formation was influenced by basement structures, local carbonate platforms (Sabine Island Complex), and salt movement that was associated with the opening of the Gulf of Mexico (Hammes, 2012). The focus of this proposed study is to provide more insight into the chemostratigraphy, lithology, depositional environments and eustatic cycles of the Haynesville Formation. This new insight is important for the true interpretation of the Haynesville Formation and its economic viability as an unconventional reservoir. In this study the Carthage core, provided by Anadarko and housed at the Bureau of Economic Geology in Austin, will be studied. The core was scanned with a Bruker Tracer III/IV electron dispersive X-ray fluorescence (ED-XRF). The core was scanned at two inch intervals to aquire a high definition study of the element percentages of the Carthage core. For the major elements for major elements (e.g. Si, Ti, Ca, Al, Fe, Mg, and K), the instrument was run for thirty seconds per sample. While for the trace elements (Ni, Cu, Zn, Th, Rb, U, Sr, Y, Zr, Nb, and Mo), the instrument was run for ninety seconds per sample. Using previously drilled powder samples by Pukar Manali, x-ray defraction (XRD) was performed. Also, a core description for the entirety of the Carthage core was performed. For this core description each box (34 in total) was broken down into three rows; each containing three feet of core. A detailed description was created using fabric/structure, inclusion, color and fossil accumulation as guidelines. Currently the preliminary results have indicated that the clay fraction is being diluted by the carbonate fraction. Additionally a majority of the bulk elements mainly Si, Ti and K are associated with the clay fraction and show a linear correlation with the clay indicator, Al. Furthermore geochemical proxies, such as the association of Ca to Al, will help in the determination of eustatic cycles. The eustatic cycles can be broken down into 4th and 5th order cycles such as Milankovitch cycles.