The claryville clay and early glacial drainage in the Cincinnati, Ohio, region

Abstract

The Claryville Clay is lacustrine sediment that has been preserved in an entrenched meandering valley beyond the maximum extent of glaciation southeast of Cincinnati, Ohio. Deposition of this and related preglacial material occurred when the north-flowing rivers of the region were dammed by an early episode of glaciation. Although the Claryville Clay is pre-Illinoian in age, its “normal” remmant magnetism suggests that deposition occurred within the past 690,000 years. On the basis of variations in clay mineralogy, grain size, and sedimentary structures, three lithologic units of the Claryville Clay are defined. The upward progression of sedimentary characteristics in the sandy to silty clay is interpreted as reflecting the increasing influence of the southward-advancing glacial dam and fluctuations in this ice margin. Retreat of the ice allowed this proglacial lake to drain. Because of drainage changes initiated by overflow from this and other ponded valleys of the region, the Claryville River valley was abandoned, and new drainage routes were established that discharged west into the Old Ohio River watershed near Madison, Indiana, rather than north into the Teays River valley of central Ohio and Indiana. Present-day rivers lie more than 50 m below the floor of the abandoned Claryville River valley.