--> ABSTRACT: Variations in Coal-Bed Thicknesses in Eastern Part of Illinois Basin, by Denver Harper; #91023 (1989)

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Variations in Coal-Bed Thicknesses in Eastern Part of Illinois Basin

Denver Harper

In the east-central part of the Illinois basin, the formation of Middle Pennsylvanian coal beds was affected by the La Salle anticlinal belt, by contemporaneous deposition of linear sandstones, and by intermittent differential volumetric changes around underlying features. These underlying features include earlier Pennsylvanian linear sandstones (75-150 ft deeper), paleovalleys of the Mississippian-Pennsylvanian unconformity (300-700 ft deeper), embayments and passes of a Silurian carbonate bank (1,900 ft deeper), and individual Silurian reefs. These influences interacted to produce abnormally thick (> 4.5 ft) deposits of the Seelyville, Survant, Springfield, and Hymera Coal Members (Pennsylvanian) within three geographically restricted areas (mining districts) in west central Indiana.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.