River-derived slackwater sediments in caves along Cheat River, West Virginia

The November 1985 Cheat River flood produced overbank, slackwater deposits in caves of the Cheat River canyon. The deposits include loamy silt, loamy sand to very fine sand, and flotsam. Sediments deposited by the November 1985 flood lie within 1 m of the established high water mark and are good indicators of peak stage. Prehistoric overbank, slackwater deposits are present in one cave. These sediments are inferred to be ≥400,000 years old and are, therefore, unrelated to the modern Cheat River. Overbank slackwater deposits are poorly preserved in the examined caves, because cave streams actively remove sediments and the warm, moist environment of the caves fosters decay of woody flotsam. Deposits of the 1985 flood are projected to survive at most a few centuries. In contrast, slackwater sediments inferred to be ≥400,000 years old are preserved within a cave shielded from significant runoff and biogenic activity.