Radiocarbon dating of glacial moraines using the aeolian biome: Test results at Bishop Creek, Sierra Nevada, California

Radiocarbon measurements on fossilized remnants of the aeolian biome, incorporated in glacial moraines in the Sierra Nevada of California, are consistent with the relative order of moraines at Bishop Creek, on the eastern slopes of the Sierra Nevada. Holocene C-14 ages correspond with periods of more effective moisture according to paleoecological and treeline data in the range, whereas Pleistocene ages are penecontemporaneous with Heinrich Events in the North Atlantic. These findings must be interpreted with caution, however, owing to a number of uncertainties, including: evidence that younger contaminants are added to till matrix; the possibility of older contaminants; the effects of pretreatment on aeolian biome remains; and processes by which organics undergo diagenesis within till matrices in different biogeochemical settings.