12 New Developments in the Late Quaternary History of the Northeastern United States and Adjacent Canada (Posters)

LATE QUATERNARY DRAINAGE EVOLUTION, STAR LAKE REGION, NORTHWESTERN ADIRONDACK MOUNTAINS, NY

Paper number: 12-3
Program: THEME SESSIONS
Time: 1:00 PM – 5:00 PM

Authors

Abstract

As the Late Quaternary glaciers retreated northward along the flanks of the northwestern Adirondack Mountains, meltwater was dammed by the ice margin. Water rose until it spilled over the drainage divides, eventually flowing to the southwest in meltwater channels. As ice continued to retreat meltwater was diverted farther north in the direction of regional slope before ponding against the subsequent ice margin, again draining to the southwest in new channels across recently exposed lower elevation drainage divides. Former meltwater channels identified in the Star Lake area of NY, are characterized by broad marshy drainage divides separating oppositely-flowing underfit streams with terraces above and below present day drainage divides.

Terraces above present day divides reveal the level of meltwater flowing in channels at times when ice blocked drainage to the north. Additionally, these terraces correspond in elevation to terraces at elevations below present day drainage divides in former meltwater channels to the southeast. Therefore, even as meltwater was shifting to the north, it may have partially occupied previous meltwater channels. By identifying paleomeltwater channels, determining the elevation of drainage divides within these channels, and the elevation of terraces within these channels, a sequence of meltwater drainage shift during deglaciation of the northwestern flanks of the Adirondack Mountains can be established.