CORRELATING GRANITE PLATFORMS IN THE WICHITA MOUNTAINS OKLAHOMA TO THE SOUTHERN HIGH PLAINS USING SRTM DATA

Sub-horizontal topographic surfaces are present at relatively high elevations in the granite bedrock of the Wichita Mountains, Oklahoma. The elevations at which these surfaces occur were investigated using Shuttle Radar Topography Mission (SRTM) data using a combination of contouring with a five meter contour interval and topographic profiles. In the eastern Wichitas prominent surfaces are present at 670 m (e.g., Elk Mt.) and at 655 m (e.g., Baker Peak). A less well developed surface also occurs at 635m. In the western Wichitas prominent surfaces are present at 635 m (e.g., King Mt.) and at 655 m (e.g., Flat Top Mt.). Vestiges of a topographic surface at 670 m are locally present (e.g., Tepee Mt.). Similar to other researchers (Harrell, 1994; Crews & Hogan, 2004) we interpret these surfaces to be remnants of older peneplains now dissected by an increase in erosion due to subsequent uplift, change in base level, or both to create the modern topography. The multi-tiered nature of these surfaces indicates their development was separated by periods of episodic uplift. The close correspondence of the elevation of these topographic surfaces in the eastern and western Wichita Mountains indicates these older surfaces are correlative and that the Wichita basement block has behaved as a coherent terrane since the formation of these surfaces. Previous attempts to correlate these topographic surfaces in the eastern and western Wichita Mountains with the Tertiary Ogallala Formation of the Southern High Plains have met with variable success. As noted by Harrell (1994) a linear fit to the surface of the Southern High Plains when projected to the east approximates the elevation of some surfaces in the western Wichitas but grossly underestimates elevations of surfaces present in the eastern Wichitas. Crews & Hogan (2004) found that an exponential fit from the surface of the Southern High Plains to the 670 m surface in the eastern Wichitas better reproduced the elevations of some of the surfaces present in both the eastern and western Wichita Mountains. If the surfaces in the Wichita Mountains are correlative with the Southern High Plains pediment then this surface has been regionally deformed (e.g., kinked) perhaps due to uplift associated with high heat flow and development of the Rio Grande Rift.