Tree-ring-dated‘Little Ice Age’ histories of maritime glaciers from western Prince William Sound, Alaska

Abstract

Tree-ring studies at 13 glacier forefields in western Prince William Sound show‘Little Ice Age’ glacial fluctuations were strongly synchronous on decadal timescales. Cross-dated glacially overrun trees at eight sites indicate ice margins advanced in the early (late twelfth through thirteenth centuries) and middle (seventeenth to early eighteenth centuries)‘Little Ice Age’. Tree-ring dates of 22 moraines at 13 glaciers show two main periods of stabilization. The earlier of these, in the first decades of the eighteenth century, overlaps with the second period of glaciers overrunning trees and marks culmination of this middle‘Little Ice Age’ expansion. Stabilization of moraines on nine of the study forefields in the latter part of the nineteenth century delineates a third interval of‘Little Ice Age’ glacial advance. The detailed‘Little Ice Age’ record from land-terminating glaciers in western Prince William Sound is consistent on a timescale of decades with four other tree-ring-dated glacial histories from across the northern Gulf of Alaska. This coastal northeastern Pacific glacial record reveals the structure of the‘Little Ice Age’ in the region and provides a strong basis for comparison with other proxy climate records spanning the past 1000 years.