SMALL, DISJUNCT LOESS SHEETS NEAR THE GLACIAL MARGIN IN THE GREAT LAKES REGION PROVIDE INSIGHT INTO PALEO-WIND DYNAMICS AT THE LGM

In this paper, I argue that the spatial study of loess deposits has great potential for advancing our understanding of paleoenvironments at the time of its deposition. My research in Wisconsin and Michigan on small, disjunct, loess sheets has been conducted with a distinctly spatial approach - to date, over 800 loess samples have been recovered from various loess sheets, in a rough grid-like pattern, so as to ascertain the spatial properties of the loess across the landscape. This geographic approach has proven to be quite insightful as to loess source region(s), which in turn can be used to infer paleo-wind directions, and even wind strength. Results to date suggest that winds were highly variable at the Late Glacial Maximum (LGM) and shortly thereafter. Although there may have been a “dominant” wind direction for this and other time periods, it is probably better to think of this paleoenvironment as one where winds from all directions were adequate to deflate source areas and deposit loess (and cover sands) on stable sites downwind. That is, loess was equally capable of being blown to the east or west of the various source areas that exist in the region. Rather than focusing on dominant wind direction at the LGM, my research results argue that competent winds existed from all major directions; loess tends, therefore, to be found mainly were landscapes were stable enough to accept and retain it.