Central Vermont was covered by 2+ miles of glacial ice just 20,000 years ago, and students in this course work to unravel the record of ice advance and retreat, and to understand changes in regional and global climate. In the Dog River valley, home of Norwich University, and in nearby valleys, glacial meltwater was temporarily impounded and large lakes filled the valleys. The water depth at the NU campus was on the order of 150-200 ft!
Below is a brief overview of research I have conducted, with colleagues, on the glacial geology of the Mad River valley, west of the Dog River. Students spent a great deal of time helping me tease out details of glacial retreat during numerous labs conducted in the Mad valley.
The image below is from a small sand and gravel pit in which the inside of a glacial-era lake delta is preserved. This particular delta built into a relatively small and high lake that we call Glacial Lake Granville that drained to the south, through the 1430′ (above sea level) Granville Notch.
The map to the right (click to enlarge) reveals the extent of ice-contact lakes that formed in the Mad River valley during glacial retreat. The glacial geology of the Mad River valley was mapped and reported on in:
Dunn, R.K., Springston, G.E. and Wright, S., 2011, Quaternary geology of the central Winooski River Watershed with focus on glacial lake history of tributary valleys (Thatcher Brook and Mad River): in, West, D., ed., New England Intercollegiate Geological Conference Guidebook, chapter C3, p. 1-32.
and for maps see (you can download free copies at the Vermont Geological Survey):
Dunn, R. K., Springston, G. E. and Donahue, N., 2007a, Surficial geologic map of the Mad River watershed, Vermont (northern sheet): Vermont Geological Survey Open File Report VG07-1A, 1 plate.
Dunn, R. K., Springston, G. E. and Donahue, N., 2007b, Surficial geologic map of the Mad River watershed, Vermont (southern sheet): Vermont Geological Survey Open File Report VG07-1B, 1 plate.
Some unusual conditions apparently existed in the Mad River valley during deglaciation. For example, very little deposition took place during Granville and Winooski times, especially of materials coarser than silt-clay. Varves, annual layers deposited in glacial lakes that undergo seasonal freezing-over, are characterized by clay with only silt partings at the most. Apparently, meltwater carried only limited, and fine, sediment into the valley. The image below shows some isolated coarse material deposited below glacial ice during retreat.