Lake Tight's origins date to nearly 2 million years before the modern era. As the Ice Age began to cool the Earth, and large glaciers began to creep south from modern-day Canada, many landforms and features were changed or destroyed, including the Teays River.
The Teays had been a river for several million years, flowing north out of the Appalachian Mountains in what is now North Carolina. The river's path traveled through modern-day West Virginia, Kentucky, Ohio, Indiana, and Illinois, finally emptying into the Gulf of Mexico, which at the time extended to southern Illinois. The glaciers of the Ice Age soon began to block the Teays, effectively damming the river and forming Lake Tight, near what is now Chillicothe, Ohio.
The lake has been the repeated topic of research over the past 100 plus years. In geologic terms, the lake's life span was short; the lake appears to have formed in the Lower or Middle Pleistocene. The reverse polarity of the clays points to an age greater than 700 ka, thus Pre-Illinoian. At its greatest size, the lake was approximately 900 feet (270 m) deep, and 7,000 square miles (18,000 km2) in size (nearly two-thirds the size of Lake Erie). When the lake finally overflowed, it created new drainage channels and rivers flowing south, in the opposite direction of the Teays River.
A GREAT LOST RIVER GETS ITS DUE
By WALTER SULLIVAN
Published: November 29, 1983 New York Times
GEOLOGISTS now believe that one of the great master rivers of world history once flowed west from the eastern portion of the United States and was responsible for much of the land and stream formation as far west as the Mississippi valley.
NEW ESTIMATES OF THE AREAL EXTENT OF PLEISTOCENE LAKE TIGHT BASED ON GIS MAPPING AND ANALYSIS
Lake Tight - West Virginia Encyclopedia - http://www.wvencyclopedia.org/articles/2279