--> Abstract: The Corbin Sandstone of Eastern Kentucky: Outcrop and Subsurface Analysis of a Pennsylvanian Age Big Braided River, by M. A. Barnhill; #90950 (1996).

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Abstract: The Corbin Sandstone of Eastern Kentucky: Outcrop and Subsurface Analysis of a Pennsylvanian Age Big Braided River

Mark A. Barnhill

A combined outcrop and subsurface study of the Pennsylvanian age Corbin Sandstone Member (Lee Formation) of eastern Kentucky was undertaken. The Lee Formation has been variously interpreted as barrier island, fluvial or tidal in origin.

The objectives of this study were threefold: 1) to determine the origin of the Corbin Sandstone, 2) to ascertain the influence of intrabasinal tectonics on the unit, and, 3) to develop a comprehensive depositional model.

The Corbin Sandstone consists, predominantly, of medium grained sandstone composed of planar tabular and trough crossbedding. Planar crossbeds are interpreted as transverse bars deposited in a low-sinuosity or braided river. Trough crossbedding is primarily associated with braid channel deposition. A fourfold hierarchy of braid channels was observed: 1) a first order channel consisting of an alluvial braidplain up to 60 kilometers wide, 2) second order channels the margins of which are observable at outcrop scale, 3) third order channels which scoured the flanks of transverse bars, and 4) fourth order channels which scoured transverse bar tops. A marine tidal sandstone caps the vertical succession in some outcrops.

Isopach mapping demonstrates that intrabasinal tectonic elements influenced basin evolution by controlling sediment thickness patterns, paleodispersal trends and paleocurrent directions within the Corbin Sandstone.

Outcrop and subsurface data suggest that the Corbin Sandstone represents a multilateral, multistory fluvial sheet sandstone deposited across a broad alluvial braidplain. Rising sea level halted sandstone deposition and resulted in tide-dominated estuarine and marine shale deposition which cap the Corbin Sandstone.

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas