AN HYPOTHESIS FOR A WESTWARD FLOWING ANCESTRAL TENNESSEE RIVER

The modern Tennesse River makes an anomolous right angle turn from awetward to a northward flowing stream south of Pickwick, Hardin countyin southwestern Tennessee. Most Coastal Plain streams flow either south towards the Gulf of Mexico or west towards the Mississippi River. Several different courses for the Ancestral Tennessee River have been proposed, including southward,and westward courses, as well as the present course. The course or courses of the Ancestral Tennessee River remains contrversial.

Textural and compositional studies of gravel fractions from Tennessee River terraces near Pickwick and terraces from the adjacent, underfit Hatchie drainage system to the west suggest that perhaps the Ancestral Tennessee flowed westward through the modern Hatchie during at least part of its history in West Tennessee.

The Hatchie terraces and the two older Tennessee River terraces are similar and dominated by quartz and quartzites and differ from the younger Tennessee River terraces which are dominated by chert. Reesman and Stearns(1989)report that the Ft. Payne cherts (Miss.) were breacheed during the rejuvination of the Nashville Dome, possibly durin the Pliocene. The Hatchie and older Tennessee terraces may predate this event while the younger cherty terraces were deposited after the breaching.