Pollen and Archaeology at Wetherill Mesa

Abstract Nine profiles of prehistoric cultural deposits at Wetherill Mesa, Mesa Verde National Park, Colorado, were analyzed for fossil pollen content. Relatively large numbers of corn (Zea) pollen occur in certain deposits of Mug House. In the alluvium retained behind low walls of two check-dams, the frequency of Zea is relatively low (.07%) but approximates the frequency of Zea pollen in soil of a garden on Chapin Mesa planted in Indian corn since 1919. Evidently, soil behind the prehistoric checkdams served as corn plots. The abundance of pollen resembling bee-weed (Cleome serrulata) suggests a more important role for the caper family in prehistoric time than would be inferred from its macrofossil record alone. The Cieome-type is common in prehistoric refuse and in human coprolite in the Four Corners area. Pollen content of matrix within a single archaeological site may vary, depending on the nature of the deposit. Although parts of their deposits overlap in time, the pollen content of (1) a trash slope, (2) a kiva, and (3) a work area within Mug House pueblo varies greatly, especially in economic pollen. Variation between profiles is reduced considerably when they are taken from the same type of deposit, that is, adjacent kivas or trash profiles. The hope that the fossil record would shed new light on the cause of abandonment of Mesa Verde was largely unrealized. The main stratigraphic event in the pollen sequence of the last 1000 years is a relative increase in juniper and pine pollen following abandonment 700 years ago. Ecologically, this rise can be explained as the result of secondary plant succession with first juniper and then pinyon invading fields when human disturbance ended. It may or may not reflect climatic change.