Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Geology and Geography

Committee Chair

Kathleen C Benison

Committee Co-Chair

Katherine R Bruner

Committee Member

Jaime Toro

Abstract

Permo-Triassic red beds and evaporites can be found in a variety of locations around the world. Largely deposited once the supercontinent Pangea formed, many of these units have historically been interpreted as marine to marginal marine deposits due to their association with evaporites. Evaporites, however, can also form in continental settings. Recent studies of red beds and evaporites within the Leonardian-Guadalupian Nippewalla Group of Kansas suggest some red beds and evaporites were deposited in acid saline lakes and associated environments. The middle to late Permian Quartermaster Group, which overlies the Nippewalla Group, has not been as extensively studied. The main goal of this thesis was to determine the depositional and diagenetic history of the Quartermaster Group of Kansas.;This research focused on the Whitehorse Sandstone, Day Creek Dolomite, and Big Basin Formation of the Quartermaster Group as observed in the Amoco Rebecca K. Bounds core no. 1 from Greeley County, west-central Kansas. Petrography and mineralogical identification were used to characterize the depositional and diagenetic features of these rocks. Field observations from south-central Kansas (Clark and Barber Counties) provided supplementary data.;Sedimentary features observed in the Quartermaster Group suggest the Whitehorse Sandstone, Day Creek Dolomite, and Big Basin Formation were deposited in continental settings. The Whitehorse Sandstone consists of red sandstone, siltstone, and mudstone with observable ped structures, root features, ripple cross-stratification, mud drapes, mudcracks, and soil slickensides. These features suggest deposition in mudflats and fluctuating water tables in adjacent soils. The Day Creek Dolomite consists of bedded gypsum/anhydrite and finely laminated red siltstones. Ripple cross-stratification, mudcracks, and planar laminae observed in bedded gypsum/anhydrite indicate deposition in ephemeral saline lake environments while ripple cross-stratification, mud drapes, soil slickensides, and root features in red siltstones indicate mudflats and soils. The Big Basin Formation consists of dark red sandstone, siltstone, and mudstone characterized by soft sediment deformation, ripple cross-stratification, mudcracks, and soil slickensides. These features suggest deposition in mudflats and the development of paleosols. In general, early and late diagenetic features observed within the Quartermaster Group suggest substantial influence from wetting and drying processes at or near the surface.;Evidence for acidity in the Quartermaster Group is based on suspect to problematic criteria. Acid saline lake deposition is postulated from indirect criteria such as unusual yellow hues observed in halite and other evaporites within bedded gypsum/anhydrite layers of the Day Creek Dolomite. Additionally, the absence of carbonates, abundance of red beds, and similarities to the underlying Nippewalla Group, a known acid system, suggest that units within the Quartermaster Group were likely influenced by acid lake waters and groundwater.;The Quartermaster Group signifies deposition in an arid to semiarid continental setting. Comparisons between these units and the underlying Nippewalla Group suggest conditions became more humid and less saline towards the end of the Permian. Additional use of highly recoverable core in future studies will help to refine understanding of the stratigraphy, nomenclature, paleogeography, depositional environments, and diagenetic history of other red bed and evaporite sequences in Kansas and throughout the western midcontinental United States.

Download

Share

COinS