Glacial Erratics

Vermont ANR Atlas: https://anrmaps.vermont.gov/websites/anra5/

While the atlas has many layers covering a wide range of topics, two of the “Geology” layers might be good to reference. The first is the “Bedrock Geology” Layer and the second is the “Glacial Lakes” layer.

Vermont Geological Survey websitehttps://dec.vermont.gov/vermont-geological-survey

A huge variety of geological information is available here.

“Friends of the Pleistocene” Guidebook https://www2.newpaltz.edu/fop/pdf/FOP2024Guide.pdf 

This guidebook is specific to northern Vermont’s glacial geology and was writtenby(and the field trips hosted by) Steve Wright and colleagues in June 2024. It contains wonderful information on our area.

Vermont Geological Society recommended book list

https://www.uvm.edu/~vtgeosoc/booklist.html

Vermont Agency of Natural Resources, Department of Environmental Conservation website:

https://dec.vermont.gov/geological-survey/publication-gis/general-interest

GLACIAL GEOLOGY:
Champlain Sea and the Champlain Valley
Friends of the Pleistocene Field Trip Guidebooks  

General Geology

The Geology of Vermont, 1996, B. Doolan, Rocks and Minerals Magazine, v 71

Lithotectonicslices,  geologic history, 2011

Generalized Geologic Map of Vermont, 2012

A Field Guide to the Geology of Northern New England by M. Dorais, 2019 (253 pages includes VT, NH & ME)

Geology of Vermont, B. Baldwin, 1982, Earth Science, v 35, no 3, 5 p

Report on the Geology of Vermont, Volumes I and II, Hitchcock et al, 1861

Educational Leaflet 1: Earthquakes in Vermont, G Springston and M Gale, 1993, 10 p

Educational Leaflet 2: Geology of Vermont Lands, M Gale and G Anderson, 1998 3 p

Poster about bedrock maps and their uses, VGS 2012

Glaciers in Vermont. Crow’s Path.

https://crowspath.org/natural-history/glaciers/

  • Glacial Geology of the Burlington/Colchester Quadrangles by Stephen Wright (PDF)
  • Glaciers & Glaciation by Benn & Evans
  • The Surficial Geology and Pleistocene History of Vermont by Stewart & MacClintock (PDF)
  • The Great Ice Age in Vermont by Elbridge Jacobs (PDF)
  • Written in Stone by Chet Raymo
  • Longstreet Highroad Guide to the Vermont Mountains by Nancy Bazilchuk
  • Lake Champlain: A natural history, Mike Winslow
  • After the Ice Age by Evelyn Chrystalla Pielou

Glacial Erratics. Wikipedia. https://en.wikipedia.org/wiki/Glacial_erratic

Lake Vermont, also called Glacial Lake Vermont, was a temporary lake created by the retreating glaciers during the close of the last ice age. The lake once included land in the Canadian province of Quebec and the American states Vermont and New York.[1] It was a geographical predecessor of Lake Champlain. Once the glacier retreated far enough north, it drained into Glacial Lake Candona, the geologic predecessor of the St. Lawrence River.

At one time, Lake Vermont may have reached nearly as far south as to what is now Albany, New York. The surface of the lake was about 500 feet (150 m) above present day Lake Champlain, and was up to 900 feet (270 m) deep. The lake contained muddy water, and the sediment of Lake Vermont contains silt/clay varves, with silt being deposited during summer and clay during the less-energetic flow of winter.

The Laurentide Ice Sheet retreated north of what is now Burlington, Vermont, about 13,500 years ago, marking the beginning of Lake Vermont. The ice damming the water at the north end, at what is now Warwick, Quebec, failed catastrophically about 12,000 years ago. The lake dropped 300 feet (91 m) within hours or days. Eventually, when the glacier retreated far enough north, salt water swept in, replacing the larger, freshwater Lake Vermont with the smaller, saltwater Champlain Sea.[2]

The lake was cold and desolate. And as much of Vermont was bare of vegetation, whose roots might have anchored all of that till in place, erosion washed significant amounts of sediments into the lake. Heavy sediment loads in the water would’ve reduced the available light to aquatic plants for photosynthesis. No plants, no animals. And indeed Lake Vermont sediments are pretty void of fossils. The lake ended catastrophically when the dam blocking water from draining into the Richelieu gave way. For more on that, check the Champlain Sea page.