Paleoecology of Beringia by David M. Hopkins

By David M. Hopkins

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Extra resources for Paleoecology of Beringia

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During the Wisconsin cycle, aeolian silt was laid down in two major pulses, of which the earlier (Happy interval) was the more important. Along many of the major rivers of Beringia, the Boutellier interval saw continued slow deposition of windblown silt on vegetated landscapes, resulting in accumulations of organic 8 Ager (this volume) reports on pollen from this site. silt with intercalated peat and pond deposits. A second but lesser pulse of loess deposition took place during the Duvanny Yar interval.

Large areas seem to have been sandy desert—an alternation of active, mobile dune complexes and of sandy defla­ tion areas. Large streams draining the glaciated mountains or carrying melt water from the Laurentide ice sheet maintained flow, but smaller streams heading in foothills were defeated by encroaching dunes on the coastal plains. The diversified topography around the presentday Bering Strait, on the other hand, may have been the site of one of the most mesic areas in Beringia. The more frequent passage of northwardmoving moist air masses may have made this area the refugium from which cottonwood, aspen, and possibly alder dispersed during the rapid climatic changes that ushered in the time of the birch zone.

However, Mackay (1963, Figs. 12. 13) shows oriented lakes in a sandy terrain on the Tuktoyaktuk Peninsula in which interlake ridges are crowned by vegetated and stabilized paraboloid dunes—a terrain so similar to the northern Alaskan sand sea of Carter (1981a, 1981b) that one is tempted to suggest that this area, some 100 km east of the Mac­ kenzie River delta, may also display large linear dunes principally of Duvanny Yar age and that the paraboloid dunes may record late Holocene reactivation.

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