An incorporation of seismic data from the Maverick Basin with other studies reveals influence from the Paleozoic Ouachita thrust on the Triassic-Jurassic Chittim Rift’s formation and the influence of this rift on the later Cretaceous-Eocene Laramide compressional event. These features are the geologic remnant of a complete cycle of continental tectonics; from collision to rifting and eventual flooding. Signatures of all of these events are preserved in the subsurface of southwest Texas. I suggest that tectonic inheritance at a range of scales is recognized in the successive imprints of the continental margins preserved within the crust of the present Maverick Basin.
The lithology and structure of a portion of the Maverick Basin in Maverick and Kinney Counties, Texas, have been reanalyzed using a new 3D seismic volume and two existing 2D seismic profiles. Amplitude reflectors in the volume were traced, mapped and correlated with reflectors in the 2D lines. These data were compared with published well data and used to develop a stratigraphic-structural model of the basin identifying the probably lithologies of the subsurface layers and key structural features. The geographic and geologic relationships established are used to illustrate a sequence of tectonic inheritance and the role of preexisting structural styles in subsequent tectonic events.
The model reveals northeast directed thrusting of Paleozoic marine sediments along a west-northwest to east-southeast striking thrust fault related to the Ouachita Orogeny. This thrusting abated against the pre-existing Devil’s River Uplift north of the study area. Subsequent to thrusting, Triassic-Jurassic rifting formed the Chittim Rift, one of many half-graben sub-basins to form in the Maverick Basin during this time. The orientation of the rift axis parallel to the Ouachita thrust fault and not to the ultimate spreading center in the Gulf of Mexico, suggests utilization of pre-existing structural weaknesses. A left lateral transform fault active during rifting potentially formed along an existing tear fault in the Ouachita thrust. Movement along this fault constrained the northern wall of the Chittim Rift as well as lead to a stratigraphically distinct mini-basin within the Chittim Rift from pull-apart motion along the fault. Compression during the Laramide Orogeny produced the Chittim Anticline in Cretaceous marine layers above the Chittim Rift. The Chittim anticlinal axis is parallel and geographically collocated with the Chittim Rift axis, providing further evidence of tectonic inheritance and utilization of pre-exiting features.
The data presented here helps to demonstrate the role of inherited structural features from specific tectonic events at the local scale on subsequent sedimentation and deformation, and how the presence of these local-scale subsurface features are significant to the overall development of the current south Texas continental margin. The resultant stratigraphic-structural model of this portion of the Maverick Basin helps to further unravel the history of the Gulf of Mexico passive margin specifically, and the development of passive margins in general, where features may not always appear to be oriented optimally to the far-field stress state. The study also presents a clear interpretation of the little-studied Central Maverick Basin area and adds to the limited studies on the region
