Atoka Group (Lower-Middle Pennsylvanian), Northern Fort Worth Basin, Texas: Terrigenous Depositional Systems, Diagenesis, and Reservoir Distribution and Quality

Quantifying the origin and geometry of circular sag structures in northern Fort Worth Basin, Texas: Paleocave collapse, pull-apart fault systems, or hydrothermal alteration?

“…Similar circular sags in this field affect gas production either by allowing water to cone up from the Ellenburger Group or by draining frac fluids during reservoir stimulation. The succeeding lower Pennsylvanian clastic deposits, the Bend Group, consist of siliciclastic and thin limestone strata of marine, marginalmarine, and fluvial environments ( Figure 2) (Thompson, 1982). These strata produce oil and gas over large areas of the Fort Worth Basin (Thompson, 1982).…”

Paleozoic sediment dispersal before and during the collision between Laurentia and Gondwana in the Fort Worth Basin, USA

“…2). The formation consists of predominantly limestone with thin beds of deltaic sandstone and mudstone in the southwestern part of the basin, and becomes interbedded with sandstone and conglomerate of the Bend conglomerate in the northern part of the basin (Turner, 1957;Thompson, 1982;Flippin, 1982). Lithofacies distribution of the Lower Pennsylvanian Bend Group suggests that the paleorivers flowed from the Ouachita orogen and Muenster uplift toward the northwest and southwest (Hentz et al, 2012).…”

Low-accommodation detrital apron alongside a basement uplift, Pennsylvanian of Midcontinent North America

“…Many fan and fan-delta deposits have comparatively great thicknesses (10 2 -10 4 m vs. 10 1 -10 2 m in the BPC) resulting from sizeable accommodation space produced by syndepositional movement along major faults (e.g., Dutton, 1980;Handford and Dutton, 1980;Soegaard, 1990;Stainstreet and McCarthy, 1993;Ridgway and DeCelles, 1993;Rasmussen, 2000;Hoy and Ridgway, 2002), but not all examples unequivocally fit this generalization (e.g., Dec et al, 1996;Eaton et al, 1999). "Granite washes" similar to the BPC (Dutton, 1980;Handford and Dutton, 1980;Dutton, 1982;Morton Thompson, 1982;Wharton, 1986;Brown, 1993;Dec et al, 1996;Eaton et al, 1999) have previously been interpreted as alluvial fan and fan-delta deposits.…”

“…2). The general understanding of coarse-clastic, uplift-marginal sediments in low-accommodation settings relative to much betterstudied, higher-accommodation analogs, such as the basinal areas fringing the Ancestral Rockies, the Amarillo-Wichita Uplift, and other basement highs (Gibbons, 1962;Dutton, 1980Dutton, , 1982Morton Thompson, 1982;Rascoe and Adler, 1983;Langford and Fishbaugh, 1984;Wharton, 1986;Johnson et al, 1988;Al-Shaieb et al, 1993;Brown, 1993;Rall, 1996), can be addressed by a study of the BPC.…”