3 Recent Advances in Archaeological Geology

Sunday, 31 October 2010
8:00 AM - 12:00 PM
Room 302

TREE RING RECORDS OF ENVIRONMENTAL CHANGE IN GLACIER BAY NATIONAL PARK AND PRESERVE, SOUTHEAST ALASKA, AND THEIR RELATION TO 18th CENTURY TLINGIT MIGRATION

Paper number: 3-16
Program: Technical Sessions
Time: 11:45 AM – 12:00 PM

Authors

Abstract

In Glacier Bay National Park and Preserve, the Huna Tlingit people have a long oral tradition that includes glacier and climate observations. These observations are vital to the reconstruction of environmental and human history in southern Alaska. Tree ring dating of the Little Ice Age expansion in Glacier Bay documents the AD 1730s advance of ice over the ancestral home of the four matrilineal clans who comprise the Huna Tlingit. One of those clans, the Chookaneidi, recount a time of privation when food was scarce, during their multiple moves in search of a new home not exposed to the cold winds coming off the glacier. They eventually settled behind a cliff near the mouth of Port Frederick in a place they named Xuniyaa, "Shelter from the North Wind", now conflated to the village name of Hoonah. At Xuniyaa they found a place to survive encountering deer in a nearby meadow. Through the powers of a shaman a large halibut was caught in a pond and a rocky reef was raised up from the water to provide shellfish.

During the time of privation the Huna Tlingit also tell of experiencing Wooch.it taakw, or "Winter following Winter", a period without a summer. Tree ring records show an abrupt decrease in ring width and late wood density in AD 1754 continuing into 1755. The temporal and spatial signature of this 1750’s event suggests volcanic forcing in the region. The source of the 1754 volcanic event is unknown, but may have been related to a major eruption of Ksudach (Volcanic Explosivity Index of 6) on the Kamchatka Pennisula, Russia, that dates to about this time. The cooling in 1754 and 1755, along with the concurrent glacial expansion, surely would have affected salmon migration in addition to impacting other food sources for the native people of the region. Tree ring dates provide an absolute chronology for the oral legends of the eviction of the Huna Tlingit from their homeland. The suggestion that the subsequent harsh conditions they experienced may be a volcanic-related cooling following the Little Ice Age ice maximum in Glacier Bay is being investigated and awaits better dating of the large-scale eruption from Kamchatka.