ARCHAEOLOGICAL GEOLOGY AT THE SCOTT MILLER, MAGNA, AND MR. PEAT SITES, SAN LUIS VALLEY, COLORADO

Geoarcheological investigations were conducted in the summer of 2012 to assess the potential for buried archaeological artifacts and to reconstruct the paleo-environment at three sites in the San Luis Valley of Colorado. All three sites contain peaty wetland deposits and have yielded both mammoth remains and cultural artifacts. Subsurface stratigraphic analysis and radiocarbon dating at Scott Miller suggest that the site was first a fluvial system depositing stratified sandy silts and evaporate sands. Thick peat deposits overlying these layers represent a localized rising of the water table sometime before ~11,530 rcybp. Woody peats representing boggy, saturated conditions alternate with organic silts representing marshy environments until sometime after ~9,120 rcybp. Mammoth bones were recorded as surface finds and embedded in the fluvial sediments underlying the peat. At the Mr. Peat site fluvial sands underlie peat deposits dating from ~13,400 to 11,300 rcybp. A similar landscape is recorded at the Magna site where mammoth bones were found in sediments underlying stratified peat deposits. Consideration of temporal and spatial patterns of landscape evolution at these sites is crucial for accurately interpreting the archaeological record and searching for buried archaeological deposits dating to specific cultural periods.