Some Chemostratigraphic Insights on the Haynesville-Bossier System
Harry Rowe¹, Pukar Mainali¹, and Stephen Ruppel²
¹ University of Texas at Arlington, Arlington, Texas 76019
² Bureau of Economic Geology, Austin, Texas 78713–8924
The fine-grained, mixed carbonate-siliciclastic, Haynesville Formation (Kimmeridgian), and the overlying carbonate-poor, siliciclastic Bossier Formation (Tithonian) preserve an archive of organic-rich sedimentation that records paleoceanographic changes along the northern margin of the Gulf of Mexico during the late Jurassic Period. Mineralogical and geochemical analysis and interpretation of sample suites from thirteen drill cores recovered from six counties (Texas) and five parishes (Louisiana) reveal that the bulk rock characteristics can be largely characterized by their relative shifts in weigh percent (wt.%) aluminum (Al), silicon (Si), and calcium (Ca), which, respectively denote relative mineralogical shifts in the concentration of clay (largely illite), quartz, and calcite. Geochemical identification of authigenic carbonates is also noted, and may ultimately play a role in defining shifts in deposition and/or pore water evolution. Furthermore, by using bulk sulfur, iron, total organic carbon and molybdenum- TOC relationships, it is demonstrated that depositional conditions within the deep portions of the East Texas Basin (ETB) were neither normal marine nor severely restricted during deposition of the Haynesville-Bossier System (HBS). As a first approximation to understanding HBS deposition in the ETB, stratigraphic changes in % Ca are used to infer changes in the flux of calcite derived from proximal carbonate factories, and the enrichment factor of molybdenum (EF-Mo) is used to further refine the chemostratigraphic approach in order to validate the correlation of the detrital signal across the part of the basin represented by the suite of cores.
AAPG Search and Discovery Article #90158©2012 GCAGS and GC-SEPM 6nd Annual Convention, Austin, Texas, 21-24 October 2012