Mississippian Barnett Shale, Fort Worth basin, north-central Texas: Gas-shale play with multi–trillion cubic foot potential: Discussion

Abstract

Listen

Translate article

Montgomery et al. (2005) have written a very useful, information-filled review article on the state of knowledge of the Barnett Shale play in north Texas, a topic of great current interest and importance. One error exists, however; the burial history that they present shows no uplift during the early and middle Mesozoic and strong uplift after the Cretaceous, whereas the geologic record indicates major pre-Cretaceous uplift. This error substantially affects the discussion of the maturation history of the Barnett and should be corrected in the literature. I will also briefly discuss the implications of pre-Cretaceous erosion and Ouachita thrusting to Barnett maturity in the deep Fort Worth basin. In Montgomery et al.'s (2005) figure 7, they show a time-depth burial history diagram for Eastland County that is contrary to what is known about the area. In that figure and in the text, they indicate that the Barnett was rapidly buried during the Pennsylvanian and Early Permian, remained at depth with no uplift or subsidence except for minor subsidence in the Early Cretaceous, then was uplifted some 1.8 km (6000 ft) between the middle Cretaceous and the Eocene (with very slight subsidence to the present). The surface geology of Eastland County and surrounding areas (Barnes, 1972) shows that flat-lying Lower Cretaceous strata (Antlers Sand and overlying Edwards Group marine carbonates) lie unconformably above units, ranging from the Strawn Group (Mingus Formation, Desmoinesian regional age) in the southeast to the lower Cisco Group (Graham Formation, Virgilian regional age) in the northwest. The west-northwest–dipping Pennsylvanian strata form part …