STREAM PIRACY IN THE TEAYS RIVER SYSTEM PRIOR TO THE IMPOUNDMENT OF PLEISTOCENE LAKE TIGHT: THE EVOLUTION OF THE TYGARTS CREEK AND LITTLE SANDY RIVER DRAINAGE BASINS OF NORTHEAST KENTUCKY

Since the 1903 publication of Tight’s Drainage Modifications in Southeastern Ohio and Adjacent Parts of West Virginia and Kentucky (USGS Prof. Paper 13), the timing and causes of the reorganization of the Teays River System into the modern Upper Ohio River System remain elusive. Tight established that the impoundment of a massive proglacial lake, and its subsequent draining, was the ultimate event in the creation of the modern Ohio River and the abandonment of portions of the Teays River. However, drainage modification prior to the impoundment of Pleistocene Lake Tight during the so-called “Deep Stage” has not been examined in detail. The Deep Stage is commonly defined as the continuous interval of deepest stream incision prior to the impoundment of Lake Tight, but observations in southern Ohio and northeastern Kentucky indicate a more complex, punctuated history. For example, the Carter County KY karst system, which evolved due to the incision of Tygarts Creek, has multiple distinct levels; and the Little Scioto River meanders through deeply incised bedrock channels both upstream and downstream of its passage across the deep, lacustrine sediment-filled abandoned Teays Valley of eastern Scioto County OH.

The question of drainage reorganization during the Deep Stage, as well as the number of discrete Deep Stage incision events, are difficult to resolve due to the infilling of many valleys with thick lacustrine sediments, as well as the capture and reversal of many stream segments, especially north of the Ohio River. To avoid these issues, we have analyzed a pair of small, adjacent drainage basins in northeast Kentucky, both of which drain to the Ohio River opposite the southern end of the abandoned Teays Valley. Within these basins, abandoned channels and saddles at higher elevations in the south and lower elevations in the north indicate a periodic capture of tributaries of the Little Sandy River by Tygarts Creek, punctuated by changes in base level due to the progressive incision of the Teays River prior to the impoundment of Lake Tight. The preservation of this time- and space-progressive example of stream capture reinforces the model of a discontinuous Deep Stage. Additionally, the south-to-north pattern suggests a possible link between Miocene-initiated uplift in the southern Appalachians and Deep Stage incision.