POST-GLACIAL DRAINAGE BASIN EVOLUTION IN CENTRAL INDIANA: IMPLICATIONS FOR PREHISTORIC HUMAN SETTLEMENT PATTERNS

The long-term variation in archaeological site distribution in alluvial settings results from how changing environmental conditions and drainage basin evolution interplay with cultural needs and choices to configure site distribution. These relationships are often believed synchronous with large-scale climate and environmental changes. Research results within the White River valley, central Indiana, USA, aimed to understand the fluvial and alluvial processes and chronology responsible for landform development and associated human settlement. Two long-term processes characterized the White River since local deglaciation. The first occurred between ~18 ka (local deglaciation) and 6 ka when channel incision and erosion/lateral migration processes dominated along the trunk. The second occurred after 6 ka when cyclical intervals of overbanking, levee formation, and vertical accretion, separated by intervals of flood plain stability, characterized the White River floodplain. Because channel migration and lateral accretion processes predominated before 6 ka, Paleoindian and Early-Middle Archaic sites are unlikely to be preserved in the valley bottom. Conversely, episodic terrace accretion process after 5-6 ka means that Late Archaic and Woodland sites, which occur in surface contexts on all terraces, may also be common in buried or stratified floodplain contexts. Our data indicate that the modern distribution of archaeological sites in the valley is incomplete due to geomorphic processes. Are conclusions are relevant to other drainage networks because similar processes and chronologies occur elsewhere in the world.