Late-quaternary stratigraphy, pedology and paleoclimatic reconstruction of the Cremer Site (24SW264), south-central Montana : a geographical case study

Graduation date: 1999This study utilizes a multidisciplinary research approach integrating the sciences of archaeology, geology, pedology and paleoclimatology. Deeply stratified and radiocarbon dated sedimentary sequences spanning the last 10,000 yr B.P. are reported for the Cremer site (24SW264), south-central Montana. Previous investigations at the site revealed an archaeological assemblage with Early Plains Archaic through Late Prehistoric period affiliations. Expanded testing of the site integrates the existing cultural record with new data pertaining to Holocene environmental changes at this northwestern Great Plains locality.\ud Detailed pedological descriptions were made along three trenches excavated at the site. The combined soil-stratigraphic record indicates that distinct intervals of relative landscape stability and soil development occurred at the site at ca. 10,000 yr B.P., 7,500 yr B.P. and intermittently throughout the last ca. 6,000 yr B.P. Periods of significant landscape instability (upland erosion and valley deposition) occurred immediately following each of the early Holocene soil forming intervals identified above, and\ud episodically throughout the middle to late Holocene. The impetus for early Holocene\ud environmental instability is attributed to generally increased aridity on the northwestern\ud Great Plains. Comparative analyses of site data with both regional environmental proxy records and numerical models of past climates (General Circulation and Archaeoclimatic models) are made to test the findings from the Cremer site.\ud The collective paleoenvironmental evidence indicates that the period of maximum post-glacial warming and aridity occurred at the Cremer site during the early Holocene period (prior to ca. 6,000 yr B.P.). These data also indicate that the existing archaeological assemblage from the site is younger than ca. 6,000 yr B.P., although future excavations may reveal cultural sequences associated with the earliest dated soils at the site. This geoarchaeological study of the Cremer site should contribute to a much needed research base in this sparsely studied region