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Tidewater glaciers have coalesced to advance through Icy Bay, Alaska, three times during the past 3800 yr. Radiocarbon ages show that the first of these expansions was underway by 3750 cal yr B.P. and culminated at the outer coast between 3505 and 3245 cal yr B.P. Subsequent recession and readvance brought the ice margin back to the outer coast by 1525 cal yr B.P. (cal A.D. 425) where it remained for about 650 yr before retreating. Tree-ring cross-dates of glacially killed trees show that the most recent ice advance was underway through the inner bay by the A.D. 1640s and reached into the outer bay in the 1810s. Historical data support ice expansion through the outer bay in the early 19th century and show a late 19th century maximum prior to 20th century retreat. These results are a significant revision and extension of previous studies of the Holocene glacial history of Icy Bay. Average advance rates for the most recent expansion were typical of modern tidewater glaciers in the inner bay but much faster in the outer bay; shallow water here may have been important to this latter phase of unusually rapid advance. [ABSTRACT FROM AUTHOR]

Presents a study which applied the lichenometry process to glacial moraines in Alaska, U.S. and Kamchatka in Russia. Topography and climate of Alaska; Dating of glacial moraines; Calibration of radiocarbon ages.