Date of Graduation
Master of Science in Geospatial Sciences
Geography, Geology and Planning
Missouri, Weaubleau structure, meteorite impact, breccia, Mississippian
Geology | Physical and Environmental Geography
The Weaubleau structure of west-central Missouri formed during a mid-Mississippian (latest Osagean or earliest Meramecian Series) marine impact. The structure is slightly elliptical in shape and unusual because of its eccentric inner and outer rings. The inner ring is approximately 8 km in diameter and is interpreted as the "central" uplift area. The outer ring is approximately 19 km in diameter; it constitutes the tectonic rim, within which rocks are mildly to intensively deformed. The eccentricity of the rings is interpreted as a result of low-angle impact on a heterogeneous target rock succession of carbonate and shale with varying material strengths. Six types of breccia are associated with the impact: mega-block, resurge, fracture, injection, dilation, and crystalline basement facies. The Vista 1 core, used in this study, was recovered from the "central" uplift area. It contains all six breccias. Clast analyses were completed to determine the size, provenance, lithology, and volumetric characteristics (clast vs. matrix) of each clast that was intersected by a centerline. This data allow interpretations to be made about crater formation and depositional and emplacement processes after meteorite impact. With clast size graphs, a bimodal distribution and clast distribution is found. Lithology graphs show that the distribution of clasts in the breccia mimics local undisturbed geology. Two regimes of deposition were present, a debris type flow and a water-based flow. These interpretations help elucidate the possible deformation associated with possible future meteorite impacts.
© Kevin Edward Moon
Moon, Kevin Edward, "Deposition and Emplacement Characteristics of the Weaubleau Breccia: Indications From Clast Provenance and Analyses" (2012). MSU Graduate Theses. 2164.