EUSTATIC AND TEC'I'ONIC CONTROL OF SEDIMENTATION IN THE PENNSYLVANIAN STRATA OF THE CENTRAL APPALACHIAN BASIN CHESNUT, Donald R., Jr., Kentucky Geological Survey, 228 Mining and Mineral Resources Building, University of Kentucky, Lexington, KY 40506-0107 Analysis of Pennsylvanian rocks in the Central Appalachian Basin reveals eustatic and tectonic controls on sedimentation. Large-scale basinal features were controlled by tectonics. An Early Pennsylvanian unconformity represents erosion of mid-Carboniferous foreland basin deposits and marks uplift of the foreland basin. The tectonic cause of the uplift may have been relaxation or collisional braking. Distribution of post-unconformity Early Pennsylvanian strata shows that the Early Pennsylvanian foreland basin was underfilled, i.e., the . forebulge had not been crested. Alluvial deposits derived from the Appalachian highlands were transported to the northwest toward the forebulge. The only outlet available to further sediment transport was toward the southwest, between the alluvial wedge and the forebulge. Crossbed measurements of the Lee sandstones support a southwestern trunk transport system. Sediments may ultimately have ended up in the Ouachita Trough via the Ouachita-Southern Appalachian foreland basin. This southwestern transport was periodically interrupted by northeastward transgression, represented by marine strata in the major marine transgression cycle. The extensive nature of Middle Pennsylvanian Breathitt coal beds and marine strata may mark a period of overfilling of the foreland basin and cresting of the forebulge. Chronologic analysis of the Breathitt Formation supports a eustatic control for the coal-clastic (CC) cycle (=Appalachian cyclothem), modulated by the 0.43 ma orbital periodicity. Peats deposited at lowstand were preserved as coals. The major marine transgression (MMT) cycle (2.5 ma)(=5 to 7 CC cycles) was controlled by an unknown eustatic cycle or periodic tectonic mechanisms. The Breathitt coarsening-upward trend (12-20 ma?)(5 to 8 MMT cycles) represents increasing intensity of the Alleghenian Orogeny.