--> ABSTRACT: Sedimentary Insights of the Upper Kimmeridgian Haynesville and Tithonian Bossier Shales on the East Slope of the Gilmer Platform, East Texas, USA, by Frebourg, Gregory; Hammes, Ursula; #90142 (2012)

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Sedimentary Insights of the Upper Kimmeridgian Haynesville and Tithonian Bossier Shales on the East Slope of the Gilmer Platform, East Texas, USA

Frebourg, Gregory *1; Hammes, Ursula 1
(1) John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin, Bureau of Economic Geology, Austin, TX.

Sedimentary features of the Haynesville and Bossier Formations were studied on a set of five cores drilled along the east slope of the Gilmer Platform, East Texas. Thirteen sedimentary facies were determined, seven of which are related to sedimentary events and six of which record ambient depositional conditions. These facies were grouped into four units. The basal unit is characterized by high-energy mass-wasting deposits evolving downdip and grading vertically into more distal flows as the shoreline shifted landward, which were probably deposited as the result of ongoing halokinetic activity and/or water-column overburdening during contemporaneous sea-level rise. The lower unit shows marine pelagic sediment (marine snow) alternating with distal turbidites gradually becoming rarer and absent. The middle unit consists of marine-snow deposits, with increasing occurrences of tempestites or tempestoturbidites. Finally, the last unit, which corresponds to the Bossier Formation, is formed by prodelta-slope deposits. The high organic content of this shale system was probably generated by an upwelling cell in conjunction with periodic input of iron-rich dust windblown from the neighboring arid areas, as well as nutrient input from rivers in the north and northeast. The depositional depth of this shale system could not be precisely assessed. It probably deepened from a mass-flow-prone slope of a carbonate platform without surpassing the prodelta-front depth at the onset of the second-order regression. This sedimentologic evaluation of the Haynesville shale-gas basin not only characterizes occurrence of its potential productive facies but also provides information about similar shale-gas systems.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California