The following is a summation of each T level and time, aimed at an overview of deglacial history. In writing the preceding Section 2 of this report about ice margin features, especially in regard to Ice Tongue Grooves and Calving Ice Margins, I found it necessary to provide advance information about deglacial history, simply for me to understand the nature of these ice margins and associated features and as well to then present them in a meaningful way. In the writing of this Section III on Regional Deglacial History it became apparent that this led to redundancy and repetition. Thus, I considered moving the earlier Section 2 historical information to this Section 3. However, Section 2’s historical perspective is more local, whereas the focus here is more regional, including adjacent portions of New York, Quebec, and New Hampshire. Thus, whereas these sections entail some redundancy I decided to retain historical information in both Sections.
The following discussion includes maps depicting the ice margin on a Statewide basis, extending into neighboring areas. As noted previously, owing to VCGI limitations it was necessary to trace ice margins from VCGI to the base used here for presentation of the maps below by usage of a crude, imprecise manual method. Thus, it is again stated that the ice margins on these maps are imprecisely drawn. More accurate positions of ice margins are given on VCGI maps. The intention here with the maps below is only to give a schematic sense of these margins.
Also as indicated previously, this study was inspired by the identification of moraines by previous research in Quebec which suggested the concept of a “Bath Tub Model,” and raised the question about possible correlation of these moraines with features in Vermont. Thus, the maps below and associated discussion examine the correlation of Vermont ice margins with Quebec, which as well is discussed in detail in Appendix 2 for Locales in the Missisquoi Basin. Also, correlation with moraines in New York and New Hampshire is of interest. The New York correlation was done largely based on information provided by David Franzi; the opinions given here are my own and not David’s. However, as explained below this was done crudely and very approximately to give only a very general sense of the possible configuration of the western margin of the Champlain lobe. The same applies to correlations with New Hampshire. Obviously, the regional deglacial history requires further study by others, including southward in New England. The suggestion that en masse stagnation occurred in the Connecticut Basin raises questions about the regional ice sheet history, similar to the identification of a separation of ice masses in northern Maine from the parent ice sheet in Quebec, which obviously raises the question as to if and how these Disconnections may relate to the deglacial history to the south in Massachusetts and beyond. It is believed that en mass stagnation occurred late in the deglacial history of the Laurentide ice sheet and therefore was primarily limited to the Connecticut Basin in Vermont and of course neighboring New Hampshire.
The regional deglacial history is of interest as an academic matter, but as well in regard to Glacial Dynamics related to global warming. For me personally, while I am intrigued about deglacial history as a matter of curiosity, the issue of global warming for present day ice sheets and glaciers is a more pressing concern for the environment and the global communities, especially those likely to suffer from sea level rise, agricultural disruptions, water supply problems, and so on. A recent NY Times article about the “crying” sounds of a “dying” glacier is haunting and compelling. 1 https://www.nytimes.com/video/opinion/100000010222666/crying-glacier.html The maps below for me cry out for further study, both for the sake of academic curiosity and as well in regard to present day global warming concerns.