FROM PITTSBURGH TO CAIRO: PLEISTOCENE EVOLUTION OF THE OHIO RIVER DRAINAGE

Abandoned meanders, found between Marietta and Wheelersburg, are of a Teays age river, and are located at an elevation of 52 to 58 meters above the bedrock channel excavated during the Deep Stage. The gradient of this ancient river merges with the abandoned Teays level found between Huntington and Wheelersburg. The Minford Clay found at this elevation in many areas of Ohio and West Virginia is magnetically reversed, and likely predates the Brunhes Chron. An average incision of 55m between OIS 20 and the end of the Deep Stage around 150 ka (OIS 6) yields a rate of about 0.085 meters per 1,000 years (m/ka). Using this rate to calculate ages of terraces found at East Liverpool and Beaver at the Ohio River, and at Muncy, Harrisburg and Marietta along the Susquehanna River permits the proposal of a chronology that shows the earliest drainage changes to be Pleistocene in the Teays drainage, and that the formation of the integrated Ohio River is coincident with OIS 20.

The buried Teays-Mahomet River that flowed from western Ohio through Indiana and Illinois towards the Mississippi drainage has a youthful appearance in the area of eastern Indiana. The easternmost portion in Indiana is filled with Wilshire glacial till (Marion Valley Plug), and is approximately 65 meters deep. Using the 0.085 m/ka rate of incision, a duration of 760 ka is proposed, which puts the initiation of this channel at about 1.5 Ma, possibly coincident with OIS 52, a significant glacial seen in Ocean Core data.

A chronology starting around OIS 78 (2.0 Ma) is proposed, that shows that much of North America that now drains to the Mississippi was initially draining to the north, then was gradually reversed, first in the Missouri drainage, then in the central and eastern parts. The drainage changes in Ohio and Pennsylvania may be related in timing to the Mid Pleistocene Transition that permitted the development of the larger ice sheets in the eastern Laurentide region, with events seen at OIS 20, 6 and 2 in southern Ohio and Indiana, while additional stages appear to be present in northeastern Ohio and Pennsylvania. Advances during OIS 3 are projected to have occurred simultaneous with Greenland Interstades, specifically the (Ontario) Sunnybrook till during GIS 12, and the Seminary till during GIS 8.