Holocene glacial and tree-line variations in the White River valley and Skolai Pass, Alaska and Yukon Territory
Denton GH and Karlen W. 1977. Holocene glacial and tree-line variations in the White River valley and Skolai Pass, Alaska and Yukon Territory. Quaternary Research. 7:63-111
Data on dendrochronology, lichenometry, C-14 ages, and stratigraphy for drift to the eastern and northern lobes of the White River ash were analysed; and they describe two major intervals of glacier-treeline interactions. One of these is concurrent with the well-known Little Ice Age; the other is dated from 2900 to 2100 yr BP. Moraines suggest fluctuating glacier expansion between AD 1500 and the early 20th century. Though much of this century has been characterized by glacial retreat, it probably is premature to declare the Little Ice Age over. The complex moraine systems of the older expansion lie immediately downvalley from Little Ice Age moraines. This suggests that the two expansion intervals were similar events in the Holocene and, thus, that the Little Ice Age is not unique. Dendrochronological data show that spruce immigrated into the valley to an altitude of at least 3500 ft by 8020 yr BP; this is about 600 ft below the present treeline. Subsequent intervals of treeline are in accord with glacier recession. These data corrolate well with a detailed Holocene tree-ring curve from California, suggesting a degree of synchrony between the areas. This synchronism is strengthened by comparison of glacier records from British Columbia and Mt. Rainer.
- Type
- Journal Article
- Authors
- Denton, George; Karlen, Wibjorn
- Units
- WRST
- Keywords
- carbon dating, Dendrochronology, Geologic History, Geology, Glaciers, Holocene, Physical Sciences, Public Record, Skolai Pass, Stratigraphy, White River Ash, White River Valley