Chronology of Neoglacial Moraines in the Dome Peak Area, North Cascade Range, Washington

Miller, C

Dendrochronology, tephrochronology, and lichenometry, together with geological evidence establish a chronology of glacier fluctuations during Neoglaciation in the Dome Peak area. Tree-ring counts proved to be the most satisfactory method for dating moraines. Dated W and Y ash layers in the Dome Peak area made it possible to assign limiting ages to some glacial deposits. Lichenometry could not be used reliably for absolute dating, but proved useful in relative dating of Neoglacial deposits. The earliest recognized Neoglacial advance in the area was that of South Cascade Glacier about 4,900 years ago. South Cascade, Dana, and Le Conte glaciers reached their Neoglacial maxima in the 16th century and subsequently built moraines in the 19th and 20th centuries. Chickamin Glacier, however, reached its Neoglacial maximum in the 13th century and later built several moraines between the 16th century and the early part of the 20th century. The apparently anomalous behavior of Chickamin Glacier may reflect a steeper profile and higher accumulation area than for the other three glaciers. Glacier fluctuations in the Dome Peak area during the later part of Neoglaciation appear to be broadly synchronous with those elsewhere in the Pacific Northwest and are in agreement with a generalized curve constructed by Porter and Denton (1967). The Neoglacial record, however, is incomplete, for no evidence was found of an early period of glacier expansion about 2,800 to 2,600 years ago, which is well documented in other parts of western North America.

Chronology of Neoglacial Moraines in the Dome Peak Area, North Cascade Range, Washington

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