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Project Details

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Project Information Sheet 1999-12

Conodont studies related to the coal-bearing rocks of Indiana

Funding Source:	Indiana Geological Survey and Lake Superior State University
Status:	ongoing — Definition of status type
Project Director:	Carl B. Rexroad

Issue

Correlation of coal-bearing strata

Objective

The Indiana Geological Survey is using conodonts (phosphatic microfossils) to more fully understand the coal-bearing strata of Indiana. One purpose is to use conodont paleoecology in conjunction with petrographic studies to assist in understanding the complex, shifting depositional patterns, especially those related to varying sulfur content in coals, variations in the roof rock above coals, and in the continuity of the rocks. Time-stratigraphic data as well as paleoecologic data are needed for paleoclimatic studies related to U.S. Geological Survey studies. These data also will aid in sequence-stratigraphic studies now in progress, which will clarify stratigraphic relationships throughout the Eastern Interior Coal Basin and will help unify terminology among the three states involved. More accurate correlations will also produce a better framework for lithologic studies in this interval and may lead to a time zonation suitable for use on a continental scale. Collections for conodonts are being made in the marine units (mostly limestone and black shale) associated with the coal beds of Indiana.

Approach

One component of the study is collecting conodonts from individual marine units over broad areas; the other component is sampling long cores to provide vertical continuity, which can be problematic in working with limestones that are only presumed to be more or less contemporaneous and more or less continuous in lateral extent. The collections are processed for the fossils and then interpretations of the resulting data are made.

Products

Eleven abstracts have been published to present preliminary information, and five papers have been published giving more detailed results. Collecting continues as does the detailed interpretation upon which more papers will be published. The depth of water during deposition of some rock units has previously been misinterpreted as have been the age relationships between two units thought to represent the same interval of geologic time. One paper has been accepted for IGS publication and another manuscript is nearly completed.

Benefits

This study will benefit coal producers and coal users in Indiana.

Locations Affected:

Clay Daviess Dubois Fountain

Gibson Greene Knox Outside Indiana

Owen Parke Pike Posey

Spencer Sullivan Vanderburgh Vermillion

Vigo Warren Warrick

Information Updated February 2, 2007

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