T21 Terrestrial Impact Breccias

Sunday, 22 October 2006
8:00 AM - 12:00 PM

GEOLOGIC MAPPING OF THE WEAUBLEAU STRUCTURE, WEST-CENTRAL MISSOURI

Paper number: T21-5
Program: Technical Sessions
Time: 9:15 AM – 9:30 AM

Authors

Abstract

The Weaubleau structure is an area of intensely deformed strata located 100 kilometers north of Springfield, MO. The Weaubleau structure lies along the 38th parallel with two other widely accepted impact structures, Decaturville and Crooked Creek [1, 2]. Mississippian and Ordovician carbonates in this area have been fractured, folded, faulted, and locally brecciated. An 11-kilometer-diameter circular drainage feature coincides with the main outcrop belt of this breccia. Pennsylvanian shale and sandstone that partially overlie the structure are undeformed. Various lines of evidence suggest the Weaubleau structure is a probable impact, including stratigraphic uplift and microtextures that resemble shock features in isolated quartz grains from the breccia, but these have not been thoroughly characterized [3].

Detailed geologic mapping of the structure is essential for characterizing and understanding the processes by which the structure formed. Mapping methods include examination of large-scale aerial photographs and remotely sensed data verified by field observations, integrated with the use of geographic information systems (GIS) software. A provisional geologic map provides a base and context for examining possible impact features. This project will produce a detailed geologic map and an assemblage of GIS products for the Vista quadrangle that highlight the structural deformation and distribution of rock types associated with this feature. Funding for this project is provided in part by the USGS Educational Mapping Program (EDMAP), the Barringer Crater Company, and Missouri State University Graduate College.