Sedimentologic and Stratigraphic Effects of Episodic Structural Activity During the Phanerozoic in the Hugoton Embayment, Kansas USA
Watney, Willard L.; Youle, John; Hedke, Dennis E.; Gerlach, Paul; Sorenson, Raymond P.; Dubois, Martin K.; Nicholson, Larry; Hansen, Thomas; Koger, David; Baker, Ralph
The 10,000 km2 Hugoton Embayment (HE) is a relatively shallow, <3 km deep, northerly extension of the Anadarko Basin, where sediment thickness is up to 12 km. The Anadarko Basin is bordered on its south by the NW-trending Amarillo-Wichita frontal fault zone with up to 10 km of total structural relief. The HE is defined by a set of regional fault zones including high angle reverse with offsets in excess of 200 m confirmed by regional 3-D seismic. The timing of these northern faults, located some 120 km north of the main frontal fault system, coincides with major tectonic activity (late Mississippian through middle Pennsylvanian). Abrupt shifts in the fault systems between NW-trending and N-NE trends are sites of large (5+ by 3 km long), parallelogram-shaped horst blocks on NE sides and adjoining grabens on SW side bounded by reverse faulting down to the west and south suggesting a system of synthetic NW-trending right lateral and antithetic N-NE trending left lateral strike-slip faults.
Faulting is closely associated with a 100 km long southward draining Chester-age incised valley. While main faulting post-dates the valley incision, possible deep karst and faulting have created linear valley segments proximal to horst blocks while valleys meander in segments between. Later faulting linked to karst formed an updip trap for the Chester reservoir in Shuck Field. A NW-trending flexure north of Shuck Field separates a narrow valley system to the north from a broad, tidal dominated, siliciclastic complex to the south.
Subdued structural movement, particularly along older structural features, continued during the upper Pennsylvanian and into the upper Permian expressed as persistent flexural folding. A series of N-S trending horst blocks and satellite anticlines became the locus for stacked ooid/grainstone shoals.
Laramide and post-Laramide deformation led to additional flexure above deep structures leading to widespread dissolution of shallow (<450 m) halite beds in the Lower Permian strata. Dissolution fronts are closely related to the underlying structure and are expressed in surface geomorphology. This evaporite karst contributed to accommodation space for the Pliocene High Plains Aquifer.
The structural geometries in the HE suggest strike-slip faulting that extended from the Anadarko Basin during peak tectonism. Regional faults and flexure closely corresponds to a template of Precambrian basement structures that are revealed by multiple data types.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013