Structural controls on Late Cambrian and Early Ordovician carbonate sedimentation in eastern Kentucky

Abstract

Correlation of wireline logs for 102 wells. Subsurface distribution and lithofacies variation of the Knox Supergroup and the Ottawa Supergroup (excluding Trenton Group). The Knox Supergroup (dolomite) is subdivided into the Upper Cambrian Copper Ridge Group and the Lower Ordovician Beekmantown Group. The Middle Ordovician lower Ottawa Supergroup is subdivided into the Lower Chazy Group (shales, sandstones, and carbonates) and Black River Group (limestone). Comparison of the isopachs of the supergroup units. Localized depocenters in the isopach maps are interpreted as temporary reactivation of faults within segments of the Rome Trough. An arch-feature oriented normal to the trough structure is common to all mapped units. The location of the arch feature within each group isopach is different and appears to be related to shifts in depocenter activity in the trough. The rejuvenation of depocenters which actively influenced lithofacies variation and distribution can better explain the lithostratigraphic trends and relationships of the Beekmantown Group, the St. Peter Sandstone Formation, and the remainder of the Lower Chazy Group.--Modified journal abstract.