A 6,500-year pollen record from a wet meadow site in central Nevada.

摘要

Paleoenvironmental reconstructions done throughout the Great Basin have helped identify several climate periods in the Late Holocene. Pollen analysis was done on sediment from a wet meadow in the Toiyabe Range of central Nevada in an attempt to provide a continuous record of climate change and corroborate other lines of evidence from the region. The meadow deposition was not continuous, however the analysis revealed several wet/dry oscillations in climate over the last 6,500 years. A strong wet signal was interpreted from high sedge pollen percentages after 3,800 cal yr B.P., placing the event within the time frame of the Neoglacial. A sharp decline in sedge pollen and increase in grass pollen marked the occurrence of drier conditions around 2,020 cal yr B.P. This increase in aridity corresponds with both pack rat midden and geomorphic evidence from the area. In addition, the occurrence of thick (1–2 cm) charcoal layers suggest the presence of at least two large scale fire events during the Holocene.