Blue Mountain transverse structures: Latimer County, Oklahoma
This research investigates a previously suggested transverse structure in the Blue Mountain area of west-central Latimer County, Oklahoma. The study is located in a 100 sq mi area between the Choctaw and Ti Valley thrust faults of the Ouachita Mountains frontal belt of southeastern Oklahoma.^ The investigative approach includes the construction of a series of dip and strike cross sections in order to determine the structural geometry, chronology, and other features of the study area. The cross sections are based on surface geology, available oil and gas wireline geophysical surveys (commonly known as electric logs), which measure a variety of physical properties, and published seismic data. The cross sections are used to determine (1) the fault geometry and chronology, (2) thrust distances, and (3) shortenings at a specific horizon.^ The following features associated with the Choctaw thrust system of the Ouachita frontal belt are specifically addressed: (1) The geometry and chronology of the principal thrust fault and the multiple splay imbricates of the Choctaw thrust system. (2) The horizontal distance, thrust distance, and shortening distance of the Choctaw thrust system. (3) Two northwest-southeast trending transverse structures (tear faults) that partition the thrust belt into segments. (4) The triangle zone, which is a structural feature found at the transition of the Ouachita frontal belt and the Arkoma basin.^ The Ouachita orogen is the belt of deformed Paleozoic rocks flanking the southern margin of the North American craton. It is the result of a Late Paleozoic tectonic event that involved the closing of an ocean by the collision of Gondwanaland with the North American craton (Laurasia). This action caused subduction of the North American plate beneath a growing accretionary prism and created companion provinces, the Ouachita Mountains and the Arkoma basin of western Arkansas and southeastern Oklahoma.^ The Ouachita Mountains proper lie south of the Arkoma basin and are characterized by imbricate strike ridges and valleys. In Oklahoma, the Ouachita Mountains are separated into three belts based on stratigraphy and structural style which are, from north to south, the frontal belt, the central belt, and Broken Bow uplift. There are three definite zones of faulting in the Ouachitas. They are: zone 1, from the Choctaw fault to the Ti Valley fault; zone 2, between the Ti Valley fault and the Windingstair fault; and zone 3, south of the Windingstair fault.^ Analyses of the cross sections lead to the following conclusions: (1) Extensional-faulted pre-Mississippian rocks underlie the study area. (2) The Springer Shale and Johns Valley Shale, both of Morrowan age, are the principal decollements and glide horizons for the Spiro-Wapanucka unit of the Choctaw thrust system. (3) The dip cross sections depict the structural configuration of the Choctaw thrust system. They provide the principal elements necessary to quantify thrust and shortening distances that define transverse structures. (4) The striking differences of shortening distances of the three dip cross sections require that two tear faults, "W" and "E" be established. They show right lateral and left lateral movement, respectively. (5) Timing of the Choctaw thrust system and the tear faults is concurrent and is at least Late Atokan, and possibly Desmoinesian, or later. (6) The triangle structure is defined by inference in two of the dip cross sections. (Abstract shortened by UMI.) ^
John, Charles Bedford, "Blue Mountain transverse structures: Latimer County, Oklahoma" (1995). ETD Collection for University of Texas, El Paso. AAI9618638.