A Neoglacial Pollen Record from Osgood Swamp, California
|A Neoglacial Pollen Record from Osgood Swamp, California
|Year of Publication
|University of Arizona
A core from Osgood Swamp, California, which is located south of Lake Tahoe, in the Sierra Nevada, was analyzed every odd centimeter to depth of 61 cm. The Hypsithermal to Neoglacial transition occurs in the 51 to 49 cm interval. Pinus shows four distinct peaks and troughs, varying more than the other pollen types in the core. The Ericaceae show two distinct peaks accompanying the Pinus lows. Pollen analytical and ecological considerations indicate that bog heaths are the source of the Ericaceous record. The Ericaceae peaks are believed to represent periods of moist coldness corresponding to Neoglacial events in the Sierra Nevada. Correlation of an ash layer at 180 cm, immediately above a radio carbon date of 699 ± 300 B.P. with an ash layer at 170 cm in my core, and other considerations, give an inferred sedimentation rate of about 47 yr/cm in my core. This places the Ericaceae peaks at about 100 A.D. and 1630 A.D., and the Hypsithermal to Neoglacial transition in Osgood Swamp at about 2400 B.P.