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This is a work in progress. Cosmogenic dates on moraine boulders and
striated bedrock indicate that Tioga ice was present in the area, both
at approximately 18.6 and 14.1 ka. We do not know if there was an ice
retreat between these two dates. "Washington" ice has a minimum
limiting age of 48.8 ka based on a single moraine boulder cosmogenic date
and an 14C AMS date of > 47,500 ka from charcoal in a soil
on the moraine. The Washington advance could be correlative with the
Younger Tahoe elsewhere in the Sierra but this, too, is indeterminate.
(James
et al., 2002)
