Lateral lithology heterogeneity due to autogenic processes in mixed carbonate and siliciclastic deposits of Cisco Group, the Eastern Shelf of the Permian Basin, King County, north-central Texas

Abstract

The stratigraphic architecture of mixed carbonatesiliciclastic systems varies along both depositional strike and dip directions. The allogenic and autogenic responses of the depositional systems to the sedimentary processes, change the degree of carbonate and siliciclastic mixing. The established model of the Eastern Shelf of the Midland Basin’s Upper Pennsylvanian and Lower Permian (Cisco Group) stratigraphy is using Wilson (1967) reciprocal sedimentation concept, where carbonates dominate the transgressive system tracts while siliciclastics dominate the highstand to falling stage and lowstand system tracts (Brown et al., 1987, 1990; Hentz et al., 2017). Numerous studies undertaken on the Eastern Shelf stratigraphy, focused mostly on dip directional changes in lithology, emphasizing allogenic (eustatic) drive in siliciclastic and carbonate sediment partitioning (Van Siclen, 1958; Galloway, 1970; Brown et al., 1973, 1987, 1990; Cleaves, 1993; Hentz et al., 2017). However, the autogenic responses of sedimentary systems are not incorporated in existent reciprocal stratigraphy models. The purpose of this research is to elaborate on the interplay of the allogenic and autogenic processes and better define the lithology distribution in the icehouse mixed carbonate siliciclastic systems by using 3D seismic interpretations and seismic inversion analysis. Our observations include a consistent siliciclastic sediment routing system favoring the same position over a carbonate platform, flowing through valleys in between carbonate buildups and depositing meandering fluvial channels, shelf edge deltas and a submarine fan.