Masters Theses

Date of Award

12-1982

Degree Type

Thesis

Degree Name

Master of Science

Major

Geology

Major Professor

Otto C. Kopp

Committee Members

Paul A. Delcourt, Kula C. Misra

Abstract

It has been shown that the elemental concentrations in some coals increase adjacent to the upper and lower contacts with the clastic sedimentary rocks. This increase is possibly influenced by the character of the overlying sediments. The purpose of this study was to determine whether the chemical character of a coal remained relatively unchanged or whether the coal underwent significant changes in petrologic and/or chemical character as a result of the lithologic character of the adjacent sediments.

The Pewee coal, which outcrops in the Wartburg Basin in northeast Tennessee, was chosen for this study. The Pewee coal is early Pennsylvanian in age and is the uppermost member of the Redoak Mountain group.

The X-ray fluorescence data show that most elemental concentrations decrease upwards within the coal, from the base to the top. At the very top of the coal, most elemental concentrations show a significant increase. Correlation coefficients for elements within the sediments and within the coal reflect the typical compositions of clay minerals. The major mineral phases identified by X-ray diffraction were kaolinite, illite, chlorite, siderite and quartz.

Several conclusions have been reached concerning the Pewee coal and the sediments associated with the coal:

1. Although minor variations in chemical composition occur laterally, the Pewee coal is relatively homogeneous within the study area.

2. Elements which tend to be soluble in low pH solutions, (specifically Ca and Mn), may react with fluids coming from the peat and be transported away from the coal-sediment contact. Chlorite is absent from the coal due to its high solubility in such an acid environment. With these few exceptions, there is little direct evidence that diagenetic processes influenced the movement of elements from the coal into the sediment, or vice versa.

3. The decrease in elemental concentrations upwards in the coal is thought to result from a gradual decrease in the amount of detritus being brought into the Pewee swamp. The sudden increase in abundance of most elements at the top of the seam provides evidence for a sudden change in environmental conditions, perhaps as the result of the establishment of a new distributing system.

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