Holocene climatic and glacial history of the central Sierra Nevada, California
Holocene climatic and glacial history of the central Sierra Nevada, California (in United States contributions to Quaternary research--Internat. Assoc. Quaternary Research, 8th Cong., Paris, 1969)
Special Paper - Geological Society of America (1969) 123: 1-47
A chronology based on geologic deposits dated by radiocarbon and lichenometry, variation in tree rings, changes in timberline position, vegetational age classes, and direct and indirect historical records shows four major periods of increased mean snowfall and cooler, cloudier summers during the last 10,000 years resulting in four periods of multiple glacial advance. These occurred between 6000 and 7000 years ago, 2000 and 2600 years ago, around 1000 years ago, and between 650 years ago and the present. The fluctuations from glacial to interglacial climate that are presently known to have occurred during the last 8000 years can be fully explained by a climatic model in which the extremes of mean precipitation of the 96 years of historical record are greater than the range of long term means for that climatic parameter.