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
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.