Pollen Dispersal and Deposition on the Ice Cap of Volćan Parinacota, Southwestern Bolivia

Abstract

Pollen, a regular component of tropical ice cores, has been shown to have great potential as a sensitive paleoenvironmental proxy in ice-core research. However, questions remain as to the modern dispersal and depositional patterns of pollen on high-alpine tropical ice caps. This information is vital to the accurate interpretation of the environmental reconstructions being derived from fossil pollen. In this study, 11 surface snow samples were collected around the caldera rim at the summit of Mt. Parinacota along the Bolivian-Chilean border. Results show that pollen concentration and assemblage are uniform in samples taken from the southwestern quadrant and the entire eastern half of the mountain. However, the pollen signatures are significantly different in the northwestern quadrant, probably due to long-distance transport of xerophytic Compositae shrub pollen from the prevailing winds. The sections of the mountain not directly impacted by the prevailing northwesterlies reflect a more locally influenced pollen assemblage dominated by grasses. These results are consistent with previous findings from the Quelccaya Ice Cap and confirm the importance of the prevailing winds in the dispersal and deposition of pollen on these high-alpine tropical ice caps.