AN OUTRAGEOUS HYPOTHESIS FOR THE ORIGIN OF PLEISTOCENE “DUNES” IN THE OHIO VALLEY AT SANDY SPRINGS, OHIO, AND VANCEBURG, KENTUCKY

William Morris Davis wrote in 1926 of “the value of outrageous geological hypotheses” in ensuring that geological inquiry does not stagnate. Perhaps not coincidentally, this came at a time when one of the most paradigm-shifting hypotheses of 20^th century geology – J Harlen Bretz’s Spokane Flood hypothesis, which would contribute to the breakdown of an absolutist view of gradualism, allowing for the recognition of periodic catastrophic events in Earth history – was being hotly debated. Two decades earlier, William Tight, a protégé of Davis, had analyzed drainage modifications in the OH-WV-KY tri-state, concluding that the Teays River had been dammed by a Pleistocene glacial advance, impounding a proglacial lake (dubbed Lake Tight), which subsequently breached a series of divides to create the modern Ohio River. Tight’s conclusion, outrageous in its own right given the prevailing paradigm of the day, nonetheless was widely accepted by his contemporaries and has stood the test of time – though subsequent research has been sporadic, at times lacking regional or temporal context, and often not reflective of shifting geological paradigms. The result is that many details of the Teays River-Lake Tight-Ohio River transition remain poorly understood. Such is the case with Quaternary deposits at Sandy Springs OH and Vanceburg KY. Mapped in 1967 as eolian deposits on terraces above the modern floodplain of the Ohio River, their rolling, waveform surface has led to the interpretation that they are Pleistocene dunes. However, this neglects the geometry of the valley as well as the role of Lake Tight. Sandy Springs and Vanceburg are located in adjacent entrenched meanders, created when the ancient Portsmouth River was incised during the Deep Stage. Failure of the ice dam near Ripley OH led to the catastrophic outflow of Lake Tight, which captured and reversed this segment of the Portsmouth River. Due to their locations on the lee sides of their respective meanders, Sandy Springs and Vanceburg would have experienced a lower flow regime. In this context, the Sandy Springs and Vanceburg deposits represent fluvial bars, with the waveform surfaces being giant current ripples created during the waning stages of flow. A nearly identical deposit, not previously mapped as eolian, with similar valley geometry occurs 37 km upriver, near South Shore KY.