Cocorp Deep Seismic Reflection Traverse Across the Southern Oklahoma Aulacogen
R. Good, L. Brown, J. Oliver, S. Kaufman, 1983. "Cocorp Deep Seismic Reflection Traverse Across the Southern Oklahoma Aulacogen", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The Consortium for Continental Reflection Profiling (COCORP) recorded deep seismic profiles across the Southern Oklahoma aulacogen. The profiles run from the Hardeman basin, across the Wichita Uplift, and into the northern part of the Anadarko basin. The location of the COCORP lines and major geologic features are shown on Figure 1. The three major findings of the survey include evidence for: (1) an extensive Proterozoic basin lying south of the Wichita Mountains; (2) thrusting of the Wichita Mountains over the Anadarko basin by several kilometers; and (3) anticlinal structures within the Anadarko basin that can be interpreted as cored by blind listric thrust faults. These features are illustrated on the two seismic lines and the generalized geologic cross section. The following summary is abstracted from more detailed description published by Brewer et al (1981, in press).
The Southern Oklahoma aulacogen is a major tectonic element of the southern midcontinent. The exact definition of the aulacogen and even the time of the initiation is unclear, with some authors using the term for the deep Paleozoic Anadarko basin (the most obvious manifestation), while others suggest it also includes the Wichita Mountains and Hardeman basin to the south. The Southern Oklahoma aulacogen was placed within a plate tectonic framework by Burke and Dewey (1973) and Hoffman et al (1974), who suggested that the aulacogen may represent a "failed" rift arm which was reactivated by Pennsylvanian deformation associated with closure of an ocean to the southeast.
Initially, subsidence was thought to have started in the Late Cambrian with transgression of the basal Reagan sandstone over Precambrian basement. However, extensive studies by Ham et al (1964) showed that thick sequences of pre-Reagan sandstone, rhyolites, basalts, and metagraywackes are also present in this area. Ham et al (1964) suggested that major downwarping of the whole area occurred in the Late Precambrian or Early Cambrian, followed in the middle Cambrian by outpouring of basalts over the graywackes and intrusion by gabbros. Faulting and differential erosion was followed in the middle Cambrian by extrusion of silicic volcanic fields and intrusion of granites, forming what is now the Wichita Mountain block. Paleozoic subsidence and sedimentation was then concentrated in the Anadarko basin with deformation culminating in the Pennsylvanian.