Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Lynch, F. Leo

Committee Member

Schmitz, Darrel

Committee Member

Kirkland, Brenda

Date of Degree

5-7-2005

Document Type

Graduate Thesis - Open Access

Major

Geology

Degree Name

Master of Science

College

College of Arts and Sciences

Department

Department of Geosciences

Abstract

The Yazoo Clay is a calcareous fossiliferous mudrock that outcrops in a northwest-southeast belt across much of Mississippi and in adjacent states. Based on over 240 X-ray diffraction analyses, the average composition of the Yazoo Clay is 28% smectite, 24% kaolinite, 22% quartz, 15% calcite, 8% illite, 2% feldspar, and 1% gypsum. Exposed Yazoo clay is weathered to a depth of 30-40 ft. and has a distinctive yellow/brown color; unweathered Yazoo is blue/gray. In most wells, smectite is more abundant in weathered clay than in unweathered clay. Mineralogic changes correlate well with engineering properties of the samples, which in general show a decrease in plasticity indices with depth. Weathered Yazoo clay exhibits greater mineralogic variability than unweathered clay. Mineralogical content also varies laterally. Lateral variation, along with correlative smectite content and engineering properties, is the reason for ?roller coaster? roadways and structural damage caused by the swelling Yazoo Clay.

URI

https://hdl.handle.net/11668/19315

Comments

mudstone||mudrock||shale||clay mineralogy||Yazoo Formation||engineering geology||swelling clay

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