Terry Hamrick

Date of Award

1997

Degree Name

Physical Science

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Ronald L. Martino

Second Advisor

Richard B. Bonnett

Third Advisor

Dewey D. Sanderson

Fourth Advisor

Protip K. Ghosh

Fifth Advisor

Leonard J. Deutsch

Abstract

Twelve facies are described from 40 measured sections the Breathitt Group from Greenup, Kentucky and Ironton, Ohio. The project area is approximately 260 square mi 1 c-s covering strata from the Mississippian age Borden formation to Middle Pennsylvanian age Allegheny formation. Facies include: 1) conglomeratic channel lags, 2) small scale, cross stratified channel sandstones, 3) large scale, cross stratified, channel sandstones, 4) small scale, tabular sandstones, 5) small epsilon cross bedded sandstones, 6) large scale, dark gray, channel form shale deposits, 7) fossiliferous silty shales, 8) bioturbated shales, 9) heterolithic channel fills, 10) biomicrites, 11) black platy shales, and 12) coals and root traced mudrocks. The Breathitt Group consists of estuarine and tidal flat facies that vertically grade into more fluvial and deltaic facies. The study area clearly shows lateral differences of facies within the Breathitt Group, with the western portions being dominated by estuarine and tidal flat facies while the eastern portions are more characteristic of alluvial and deltaic deposits.

Five marine zones were found in the study area and consist of silty to clayey shales with a low-diversity stenohaline or brackish water assemblage. Common genera include Neospirifer, Juresania, Desmoinesia, Lingula and Orbiculoidea. Localized deposits of black fissile shale contain nektonic crustaceans and other planktonic invertebrates. Several marine zones that reportedly contain abundant body fossils further south of the study area contain only marginal marine trace fossil assemblages in the Greenup-Ironton area. These are typically Cruziana ichnofacies assemblages containing abundant Conostichus, Phycodes, Cruziana, Teichichnus, and Astersoma.

The sparse marine fossil distribution is probably due to deposition within restricted coastal estuaries upon topographic highs. Due to elevation and basin dynamics, only major transgressive episodes were able to deposit open marine sediment in the Greenup-Ironton area. Restricted circulation occurred within sediment starved estuaries during transgressive episodes.

Palynologic and field analyses of the Princess No. 3 coal yield a revised structure map for the Greenup-Ironton area. This updates work done by Dobrovolny et al (1966). Strata tend to rise gradually to the west with a slight "plateau" around Lloyd, Kentucky.

Sequence stratigraphic analysis of the Breathitt Group in the study area is somewhat tenuous. The lack of extensive erosional surfaces and limited aerial extent left no reliable sequence boundaries, are made. However, a few suggestions There appears to be a pattern of third order cycles in older strata below the Princess No. 3 coal. Fourth order cycles are suggested for strata above the Princess No. 3 coal. It was possible to illustrate a transgressive, lowstand, and highstand systems tract for the Arnett Member.

A depositional history has been developed and consists of essentially three phases:1) early Middle Pennsylvanian fluvial incisement and drainage of the edge of the interior craton into small, steep valleys, 2a) the formation of estuaries and valley filling during transgressions, 2b) exposure and development of well drained soils along valley walls during lowstands, 3) encroachment of larger deltas draining orogenic source areas to the southeast during the late Middle Pennsylvanian.

Subject(s)

Formations (Geology) – Kentucky – Greenup.

Formations (Geology) – Ohio – Ironton.

Geology – Ohio – Ironton.

Geology – Kentucky – Greenup.

Breathitt Formation (Ky. and Tenn.).

Geology, Stratigraphic – Pennsylvania.

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