MAPPING AND ANALYSIS OF THE CRATERVILLE FACIES OF THE QUANAH GRANITE, WICHITA MOUNTAINS, SOUTHERN OKLAHOMA

The Wichita Mountains in southern Oklahoma expose the products of intracontinental bimodal magmatism produced during late Ediacaran-early Cambrian rifting. The Wichita Granite Group (WGG) includes roughly a dozen lithodemes, each thought to arise as separate intrusions of shallowly-emplaced magma. Decimeter-scale mapping revealed that these individual plutons exhibit modest differentiation events that constrain attributes of emplacement processes.

The Craterville granite is a newly-recognized variant within the mapped Quanah pluton. The Quanah is the second-largest body of the exposed WGG and is demonstrably the youngest of those exposed in the eastern Wichitas. As with the Quanah Granite, the Craterville is coarse grained (atypical of the WGG), forms tor topography, and exhibits elevated SiO₂ and low Ba and Sr. In contrast, the Craterville lacks the distinctive arfvedsonite of typical Quanah Granite; and instead hosts few mafic silicates. Like much of the WGG, the Craterville exhibits granophyre, which is notably absent in the typical Quanah. Although typical Quanah contains miaroles, the Craterville apparently presents a relatively elevated concentration. Exposures of the Craterville are seemingly confined to the eastern portion of the Quanah pluton. Its exact distribution and relationship to adjacent granites of the WGG is part of current mapping that incorporates extensive geochemical and petrographical sampling. Its relationship to typical Quanah is also under exploration, but we are evaluating the hypothesis that it represents a syn-plutonic portion of the Quanah intrusion subjected to a relatively intense cooling regime.