ABSTRACT: Milestones and recent advances in the study of loess, dust, and other aeolian sediment archives .

CGRG Bibliography of Canadian Geomorphology
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Abstract

Loess is the most widely distributed surficial material in the extensive non-glaciated regions of the northern Cordillera of North America, or as it is more generally known, Eastern Beringia. The region preserves a record of loess accumulation extending through much of the last 3 Ma. These records include numerous distal tephras providing independent chronology and an opportunity to assess regional accumulation through correlation of tephras. Early models favoured glacial processes and katabatic winds as a source for much of the silt in Alaska and Yukon. However, local sediment production can be shown to be regionally important in areas like the Klondike of central Yukon where rapid accumulation occurred in valley bottoms while upland sites typically lack equivalent records of sedimentation. A disconnect between upland loess and valley-bottom ice-rich loess is also seen in the Fairbanks region where upland loess is more prevalent during interstadials and interglacials relative to the full glacial, while valley-bottom sites show significant accumulations during stadials. These differences likely reflect differences in accommodation space where valley-bottoms likely behaved as loess-traps for rapid accumulation with sediment bypassing upland surfaces. At least over Middle Pleistocene timescales these records have accumulated with syngenetic permafrost providing a means to rapidly store carbon in sedimentary reservoirs during aggradation, and a potential carbon source sensitive to climate through interglacial thaw instability. These deposits are increasingly recognized as a North American version of the carbon-rich Yedoma deposits of northeastern Siberia, yet the acceptance of these eolian processes in Siberia is still controversial.

Bibliography of Canadian Geomorphology