THE TIMING AND CAUSE OF GULLY FORMATION IN THE NORTH CAROLINA PIEDMONT

Gullies are common erosional features in the Piedmont of North Carolina although little work has been done to examine how and why they form. In order to determine the timing and cause of gully formation in the area, we mapped 68 gullies in the landscape and found that the majority of them were either back-filled with alluvium or had alluvial fans at their base. We dug soil pits at a subset of the sites and examined soil development, organic content, and particle size. To test the hypothesize that the formation of gullies in the area is related to early Euromerican settlement and agriculture on the land, we also dated six charcoal fragments found buried in soil pits. Not surprisingly, we found that soils in alluvium are less developed than typical Piedmont soils formed direclty in bedrock. More importantly, radiocarbon ages cluster in the late 1700s which suggests that early agriculture and deforestation had an immediate impact on the landscape. The immediate response of the landscape to deforestation indicates that the argillic soils of the Piedmont are pre-disposed to erosion. Our results highlight the importance of erosion prevention as reforested farmland is re-logged during residential expansion.