Geologic Story of the Lower Wabash Valley with Emphasis on the New Harmony Area

Abstract

The lower Wabash Valley-215 miles as the river flows from Terre Haute, Ind., to its meeting with the Ohio Valley; 3 to 12 miles across from bedrock wall to bedrock wall; as much as 150 feet from modem alluvial plain to ancient bedrock floor; conduit for 6 1/3 cubic miles of water each year by both gentle current and angry torrent; drainer of 33,000 square miles of basin; reservoir for 750 billion gallons of ground water within the alluvial fill at any given moment; storehouse of 18 cubic miles of sediment, some in active transit but much more waiting thousands of years between legs of its fitful journey to the sea Both host to and product of a restless wandering river that forever renews its flood plain, cutting into its alluvial bed on one side and backfilling on the other; host to a river that adds a new layer of silt annually to part of the 900 square miles of lower valley flood plain; a river that erosively impinges here and there against the bedrock-valley walls, thus moving them farther apart as though demanding even more room to accomplish its ultimate task; a river that leaves telltale marks of its patient sorting through the flood-plain sediments: cutoff meanders, silted-up channel scars and sloughs, crescentic ridge-and-swale topography, valley marginal terraces, whose rising edges denote the farthest advances of the latest looping-river bends to migrate gradually by those parts of the valley. A 500,000-acre breadbasket to a nation; direct provider of such basic resources as sand, gravel, and water; secreter and protector, it would seem, of the rich coal and oil fields that extend far below the bedrock floor. The lower Wabash Valley-complex physiographic wonder; capricious (or misunderstood?) phenomenon; tireless geologic agent; artery, resource, playground, and home for prehistoric and modem man alike-what are its origins, how does it gain its boundless energy, and of what legacy does its physiography speak?