SOIL DEVELOPMENT ON FLUVIAL TERRACES NEAR CONFUSION HILL ALONG THE SOUTH FORK EEL RIVER, A CHRONOSEQUENCE WITH CORRELATIVE AGE ESTIMATES AND REGIONAL TECTONIC IMPLICATIONS

A series of tectonically uplifted strath and fill terraces exist along the South Fork Eel River near Piercy, CA. Preserved terrace surfaces, at three separate elevations, have been recognized in the vicinity of the Confusion Hill bridge construction project, located on Highway 101. At roughly 4 m, 86 m, and 113 m above the active river channel, the terrace elevations suggest continued uplift and incision of the preserved surfaces. Utilizing soil development data from each of the terrace surfaces, a soil chronosequence was developed for the Confusion Hill terraces. In comparison with the large amount of incision, the presence of young, weakly developed terrace soils indicates a relatively large local uplift rate.