After 13,000 years ago, prevailing winds relaxed from the Late-Glacial northwest and blew more equably from the west (Thorson and Schile 1995). Climate and seasonality in the Late Glacial period became responsive to altitude and proximity to the sea. Land surfaces tilted and rose with isostatic rebound that followed the ice melt and drainage of the large lakes. Continental and mountain glaciers and meltwater had scoured valleys in the north of the region, bringing river channels to very low elevations that were buried anew by late-glacial lake deposits and/or rising sea levels backing up major drainages such as the Susquehanna, Delaware, Hudson, Connecticut, and Penobscot rivers. Rivers draining toward the Mississippi, such as the Ohio, Allegheny and Monongahela systems, similarly cut deeply during glacial time, leaving high old terraces on their valley flanks, later raising the channels and bringing early Holocene alluvium over the lowest Late-Glacial terraces (e.g., Broyles 1966). The dynamism of Late-Glacial alluvial deposition may explain why rockshelter utilization is so rare among Paleoindians in North America.
[{"glaciers": "n/a", "shrinking": "n/a", "heights": "n/a"}]
[{"glaciers": "n/a", "shrinking": "n/a", "heights": "n/a"}] [{"glaciers": "mountain glaciers ", "shrinking": "n/a", "heights": "n/a"}]