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Subsurface Structural and Stratigraphic Interpretation of Morrowan Strata in the Cass Fault System of Northwest Arkansas

Leiaka Welcome
University of Arkansas, Fayetteville, Arkansas
[email protected]

During the late Pennsylvanian period major tectonic events resulted in the production of multiple structurally complex provinces throughout the state of Arkansas. The Ouachita orogeny is an example of one of the more prominent tectonic events. During the Pennsylvanian Period the northern migration of the Ouachita thrust belt contributed to the formation of four main structural and physiographic areas. These areas are not only structurally diverse, but they are also host to numerous valuable resources.

One such resource is the Mississippian age Fayetteville shale, an unconventional natural gas reservoir, located on the Arkansas side of the Arkoma Basin. The Arkoma Basin is one of the main provinces which originated during the late Mississippian and early Pennsylvanian periods. The Arkoma Basin which spans a considerable portion of Northwest Arkansas denotes a typical peripheral foreland basin characterized by an asymmetrical sediment-fill which is very thin in northern Arkansas, but thickens considerably adjacent to the frontal thrust of the Ouachita fold belt.

The Arkoma Basin serves as the southern boundary of the Cass Fault system located in north-central Arkansas. Past tectonic activity within the Cass system at the northern margin of the Arkoma basin has produced well-mapped surface structural elements. However, there is still considerable conjecture surrounding the region’s subsurface.

In this study I utilize subsurface mapping techniques to reconstruct and interpret past geologic events in order to document the regional tectonics and their impact on the depositional history within the Cass Fault systems, and it relation to Arkoma Basin development.

AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013