Relative dating of moraines using moraine morphometric and boulder weathering criteria, Kigluaik Mountains, Alaska |
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| Authors: | BRIAN J PECK DARRELL S KAUFMAN PARKER E CALKIN |
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| Institution: | Department of Geology, Uniuersiiy at Buffalo, 4240 Ridge Lea Road, Amherst, NY, 14226, USA;lnstitute of Archc and Alpine Research and Department of Geological Sciences, Campus Box 450, Uniuersity of Colorado, Boulder, CO, 80309, USA |
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| Abstract: | Six measurements of surface-boulder weathering and seven measures of moraine morphometrics were taken at 57 sites in the Kigluaik Mountains, Alaska, to test the morphostratigraphic division of five Quaternary glacial units, to test a threefold subdivision of the late Pleistocene glacial unit, and to estimate the timing of glacial advances. Group means from 70% of the relative-age measures exhibit a positive relationship with relative age of the glacial units. The measures most effective at differentiating between moraine groups were: boulder frequency, tall-boulder frequency, boulder height, distal slope, and boulder angularity. Results of dixriminant analysis indicate that moraine-morphometric measures provided slightly better classification results than those of boulder weathering. Discriminant analysis correctly classified 89% of the a priori grouped sites. Multivariate analysis supports the attempted threefold subdivision of the latest Pleistocene Mount Osborn moraines at the 0.056 level of significance. Estimated ages of 60,000 BP for the Salmon Lake and 165,000 BP for the Stewart River glacial units were interpolated by using the relative-age data and ages of 18,000 BP for the Mount Osborn and 810,000 BP for the Nome River units. |
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