CONTINUED HIGH RESOLUTION DIGITAL GEOLOGICAL MAPPING IN THE EASTERN WICHITA MOUNTAINS, SOUTHERN OKLAHOMA: POTENTIAL BENEFITS TO FEDERAL LANDS

The Wichita Mountains Wildlife Refuge (NFWS) and Fort Sill (U.S. Army) are federally managed lands that cover most of the eastern Wichita Mountains of southwestern Oklahoma. The bedrock is dominated by the exposed magmatic products of Cambrian rifting, and scientifically serves as a natural laboratory for resolving rhyolite eruptions, and the emplacement and crystallization of gabbro and shallow granite bodies. These igneous rocks were further buried under early Paleozoic carbonate-dominated sediments. The mountains are in part a product of late-Paleozoic uplift and further reflect deformation of the Laurentian interior during Pangean assembly. These uplifted landforms were subsequently covered with Permian sediments. All are presently undergoing exhumation with limited deposition of alluvial cover. Current work strives to produce a GIS product at 1:24 000 (7.5' quadrangle) scale.

Although mapping is focused on resolving igneous relationships, deformation, and stratigraphy, the product can be modified for other uses. Digital mapping facilitates versatile reporting; a standard geologic map can be quickly converted to convey characteristics useful to those tasked with immediate oversight of these lands (i.e. wildlife and land-use managers). Such information may be helpful in assessing the range of flora and fauna, in planning for fires, and in guiding public and specialized use.

Furthermore, the bedrock and cover geology in the Wichita Mountains easily translates to land-use characteristics, as they have a profound influence on weathering, erosion, geomorphology, sedimentation, and pedogenesis; the high-resolution geologic map also reveals the spatial limits of topography, soil, and vegetation. Granite exposures yield rough but elevated terrain with weak regolith which varies with the composition and microstructure of the rock. The rhyolite produces consistent thin soils on rounded, grass-covered hills. Gabbroic exposures underlie lower topography and develop thicker soils, resulting in generally increased tree cover. Each of the igneous expressions host incised stream channels, whereas Permian conglomerates resist channel formation while promoting a thick-soil grassland. And alluvial deposits foster thick soils atop loose sediments with increased vegetation.