A long time ago, from 1966 to 1980, I was on the faculty at the University of Vermont, initially involved with teaching and research on Vermont Pleistocene glacial geology. My research back then involved mapping from the Quebec border to Middlebury in the Champlain Valley and from Lake Champlain on the west into the Green Mountains on the east, generating substantial glacial history information. I published a report in 1972 about proglacial water bodies in the Champlain Basin, but I was unable to decipher the deglacial history of this region, specifically meaning the identification, mapping, and correlation of ice margins.
Whereas the Vermont Geological Survey sponsored a surficial geology research program for the entire State, by Stewart and MacClintock, which was completed in 1969 and 1970, this examined glacial history by an examination of till fabric and striations for the identification of drift sheets, and did not delineate the positions of ice margins. Also, substantial research by others subsequently has been done in recent years, but this has focused primarily on detailed mapping of local areas with inferred ice margin positions based on proglacial lake history, but not specifically ice margin positions per se. Thus, the deglacial history of Vermont, in contrast to neighboring regions, until now has not been established, representing a gap in the regional record. In time, my interests turned to applied environmental geology and hydrogeology, whereby I eventually left academia. But unrequited curiosity can be a plaguing thing and a huge motivator. So now, late in life, I am once again revisiting this history.
On a bike ride in the Missisquoi Valley in 2023 I came across glacial features that I had seen in the late 1960s, reminding me of intriguing evidence indicating that the ice sheet was present in northern Vermont in Champlain Sea time as a readvance which perhaps closed the basin once again to reestablish a higher freshwater proglacial water body in the Champlain Basin. Over the years I have kept up with the literature and realized that the Missisquoi evidence unfortunately has been forgotten. This prompted me to write an open letter to the Vermont State geologist as a reminder about the Missisquoi features and the prospect for significant information about deglacial history in this area. On a whim, I then decided to examine online information provided by the Vermont Center for Geographic Information (VCGI) for the Missisquoi and Memphremagog areas. This was intended to be brief and just for fun.
Of course, VCGI and much of its information did not exist in the 1970s. Back then, mapping was done the old-fashioned way with a USGS topo map and a shovel. In the Missisquoi area the best map then available was a 1”: 62,500” scale USGS topographic quadrangle map with 20-foot (6 m) contours, which is extremely limited. Today, advances in digital technologies have dramatically changed the process of mapping. VCGI’s digital maps are “zoomable” to a scale up to about 1:3,600, nearly 20 times better than the 1:62,500 maps, with 10-foot (3 m) contours. VCGI also makes a variety of other types of information available online, such as Stewart and MacClintock’s statewide glacial map (again these authors did not identify and map deglacial history showing changing positions of ice sheet margins, but their map and associated report contain a wealth of useful information). VCGI likewise presents other helpful information such as Vermont Highway Department soil boring aggregate maps, and the Soil Conservation Service soil type and onsite septic waste disposal favorability soil maps. VCGI also provides LiDAR imagery, which of course as is now well known for glacial geology is a dramatic technology enabling the identification of features on the landscape never before visible. From the standpoint of my studies of glacial geology in the old days, all of this is a huge improvement.
My chance bike ride encounter in the Missisquoi and my following examination of VCGI and LiDAR imagery proved to be a “slippery slope.” Fortunately, I still have my field notes, maps, and memories from those early days. The bulk of my early findings have never been published. With the benefit of my previous studies, VCGI and its LiDAR imagery and other modern technology, a review of recent Vermont and neighboring literature, plus limited new, recent field mapping, as reported here, I have revisited this subject, leading me to a better understanding of the Vermont Pleistocene.
This is the story of the deglacial history of Vermont, across the entire State, including suggested possible correlations with neighboring Quebec, New York, and New Hampshire. This has never been done before. For me, my revisit was a “voyage of discovery,” poetically speaking, finding new information, with many “epiphanies.” These epiphanies represented “a ha” moments when I suddenly understood and grasped the meaning of certain evidence. And further, these epiphanies morphed into a new paradigm understanding of Vermont deglacial history. Recognizing the need to document the basis for my findings in detail as factual evidence as my voyage progressed, I was forced to write, not knowing where this exploration was taking me. As a consequence, this report became overly long and needs to be condensed into a summary of its essence. But the details given provide documentation of the basis for my findings in this present version for the benefit of future researchers.
I refer to “paradigms,” which are powerful ways of processing information, at the very heart of human thinking. But at times our paradigms limit our ability to see and understand what is before our eyes, becoming so-called paradigm “traps.” It turns out that satisfying my curiosity required imagination to explore the evidence I was finding, hence the quotes on the frontispiece of this report. These quotes are not intended to signify that others before or after me in the 1970s lacked imagination. Rather, they serve to remind me that my personal lack of imagination was a failing. Back then, in the old days, I could have done a better job, if only… ! But, of course, it’s always easy to look back. For me, my “a ha” epiphanies thus led to a “paradigm shift, a new and different understanding of Vermont deglacial history.
I think of my entire research experience as very much like solving a gigantic three-dimensional puzzle in which some of the puzzle pieces are missing and many need to be carefully studied to be understood, with time as an additional part of the puzzle.
The complexity of Vermont’s deglacial history made it more difficult to both think through and to write this report. I have struggled first to understand three dimensional and time transgressive issues, the puzzle story as just alluded to, and then how to express or convey these as accurately, clearly, and correctly as possible, and, believe it or not, given the length of my story-telling, which at times for me seems to drone on and on, I have tried to make it as simply, succinctly, and concisely as possible. Owing to the complexity of the deglacial history, again involving three dimensional and time-transgressive ice margin recession and as well relationships with multiple proglacial water bodies, the thinking through, writing, and then editing of this report has been challenging. Even now, after many read-throughs, I am realizing that this report is imperfect. Editing, it seems, particularly taking a new look with a “fresh face,” is never ending, which is my way of acknowledging that this report both remains imperfect and needs to be condensed. I fundamentally like to write, which for me is a way of thinking. And this history has taken a lot of both thought and writing.
I am aware that this report could be substantially improved by both further research and more careful editing. I have made it the best I can, but this is a big job. “This ain’t purfect,” as my grandmother used to say about the large, complex quilts she used to patch together. For me, this study is like a large, very complex quilt. I am now an old dude who likes to bike ride and hike, paint, read, travel, and generally explore a myriad of interests. This report ain’t purfect and keeps getting in my way of doing other things. My apologies to the reader for mechanical errors, typos, misspellings, redundancies, etc. This document is so large that it is difficult for me to keep track of what I said in various sections, which is again an argument for a collaborative effort. Too many redundancies make for less enjoyable reading reading reading reading reading.! As already stated, my primary goal now is to encourage further research by others, to share my ideas, and in that respect to make the information I learned available as best I can, as soon as possible, in a limited amount of time, in reasonably good form, so that I can get back to hiking, biking, painting, and other life pleasures with family and friends.
This report was “completed” in January 2026, after three years of study and writing, when I thought I had concluded this project. However, discussions with David Franzi, newly retired professor at the State University of New York, and Etienne Brouard, then of the Canadian Geological Survey, raised questions about the Champlain lobe late glacial history, specifically my finding that the lobe extended far to the south with a readvance at a late glacial time. This prompted me to take a fresh look for a more complete, better understanding of this history using VCGI LiDAR imagery. This identified new features related to the calving and ice streaming of the Champlain lobe associated with its late glacial recession, and possibly its “collapse(?),” which are of interest not just as an academic matter about deglacial history but as well in regard to modern day global warming concerns. Follow-up field examination of these features confirmed my LiDAR findings. Rather than revise my earlier report I decided to add the new findings as an Addendum which, again thanks to my colleagues, now suggests a different deglacial history interpretation for the end of the Champlain lobe. The Addendum finds that the late glacial readvance was restricted to the northern Champlain Basin such that pre-Addendum finding of a long convex lobe readvance at a late glacial time was incorrect.
Thanks to these new findings I realized that while this report is about Deglacial History, the “When” part of the story, it also is as much about the environmental conditions around the margins of the ice sheet or “Styles” and the physical interaction between the ice sheet and these conditions, or “Glacial Dynamics” – which is to say the “Why” and “How” parts of the Deglacial History story. It turns out that understanding the “How” and the “Why” is as important as the “When,” particularly in the context of present-day global warming concerns. Thus, this report presents deglacial history, as a matter of academic interest, but as well provides significant information pertaining to modern day ice sheet global warming concerns.
Now, finally, for me personally, the many puzzle pieces seem to have come together remarkably well, telling an intriguing story which is very different than I had expected, again both in terms of the deglacial history itself, the “When” part of the story, and as well the evidence regarding the progressive Glacial Dynamics of recession, the “How” and some of the “Why” parts. For example, I have been surprised by:
- How late in time the deglaciation of Vermont occurred, and how rapidly the ice sheet receded. For more on this the reader is directed to the section of my initial report on Vermont deglacial history, and especially the similar discussion of this topic in the Addendum.
- The many and varied new types of ice margin features identifiable in Vermont. This speaks to the power of LiDAR, identifying such features, as for example Ice marginal Channels, Scabby Terrain, Ice Tongue Grooves, Ribbed Lacustrine Deposits, Headless Shoaling Kame deltas, Streaks, Scarps, Mega-Scale Lineations, Transverse Morainic Ridges, Hybrid Margins, Onset Zones, and so on. Again, these are identified and discussed in detail in both the pre-and post-Addendum portions of this report. Some of these required a lot of study, often with my understanding coming into focus as “ah ha” epiphanies. For example, my findings that Ice Marginal Channels formed along inverted polythermal Warm over Cold over Warm ice margins under unique meltwater drainage and physiographic terrain conditions was for me a breakthrough, helping me to better understand the early times of deglacial history ice sheet recession. Similarly, the evidence shows the progressive warming of the ice sheet, becoming fully Warm, which, along with meltwater and the terrain, especially given the reverse gradient setting, led to the accelerated recession of the ice sheet, as discussed in the Addendum report.
- The detailed evidence for ice streaming and calving during the final times of the ice sheet’s presence in Vermont, and most astoundingly for me the suggested “collapse(?)” of the ice sheet, all of which again reflect the reverse gradient conditions, is the most surprising and as well perhaps the important finding from this study, as it bears on modern day issues of global warming and ice sheet instability. This part of the story is told in the Addendum.
Whereas this study began with a focus on deglacial history, it turns out that Glacial Dynamics became an important part of this story. Many of the newer LiDAR based ice margin features required considerable study to understand their formation, which became an exploration of Glacial Dynamics. Similarly, putting all the pieces of this evidence together likewise resulted in a different understanding of Glacial Dynamics as an important part of deglacial history.
As just stated, I looked at this research as being just for the fun of it, the development of new hypotheses and the joy when sometimes these are confirmed – the “a ha!” moments. At this point I have satisfied my curiosity, with a better understanding of this history. For me, all of this has ended in a new paradigm-ic understanding of Vermont deglacial history.
From my perspective, this report and the story it tells represent a beginning, not the final word on the matter, with many more details remaining to be fleshed out. While I believe that the deglacial history being presented here is reasonable and plausible, and makes geological sense, with many pieces fitting together, I see this as deserving further study. The job is not yet finished, but the general sense of Vermont deglacial history in a regional context is emerging. Again, my fundamental interest in this endeavor was to satisfy my curiosity, personally, for myself. My curiosity is now satisfied, and I am happy to leave it to others to continue with the exploration and refining (or revising) this history. Hopefully my findings may provide insights for future research, because in my opinion more work certainly needs to be done. I see this report as a “provocative exploration,” as stated on the front title page, suggesting directions for future research.
This report has the makings for some sort of publication, whether a book, memoir, or whatever. In my opinion, its thoughts, findings, ideas, etc. are intriguing and have merit. This report has not been peer reviewed, but again the factual basis for my findings is given in great detail. I understand the significance and importance of peer review, providing a mechanism by which the scientific validity of reported findings can be attested. But, because a) my findings substantially depart from the current mainstream thinking, and b) I have been away from research on this subject for a long time, peer review would take more time and effort than I have available or am willing to devote at this point in life. Fortunately, web site publication provides a way to make my findings broadly available, even if not part of the formal or “official” record. Thus, my goal is to simply present my findings here, to provoke further, new thought. I am OK with letting time and history be the judge of the merits of my findings. I have reached out and shared my findings with researchers, both in Vermont and neighboring regions, and have benefitted from the exchange of thoughts.
I have decided to present my findings as a web site, given here as www.vermontdeglacialhistory.org. Again, my purpose with this report is to present my findings and to encourage open thinking and continued research whereby the ideas can be tested, refined, revised, or perhaps discarded. At this point in my life, I don’t need another publication. I am more interested in having my findings be available to suggest possible directions for future research. And again, more research clearly is needed. I am content to leave it to others to carry on with the hard job of fleshing out and perhaps revising the story. I am especially interested in encouraging students to take up where I left off, all the more so in that it is future generations who have a vested interested in what happens to modern ice sheets. In fact, I actually wrote this report, thinking of students as my audience (once a teacher, always a teacher). I am available to help!
Whereas it is not my goal for this report to be the launch of a new career in an ongoing study, as I have other pressing interests as just stated, I would welcome any feedback, questions, or dialogue. I have the capability of making changes to this report or adding comments from others. My email address for such communication is: vermonticeman@gmail.com. A hardcopy of this full report can be provided in pdf format.
Finally, an expression of gratitude. To my son –a health economist at Stanford University and the Veterans Administration, who has been remarkably helpful and supportive with all sorts of suggestions about how to make this a better report. To my daughter – the CEO of one of the major philanthropic organizations in the country – whose managerial capability and spirit of giving stands as a role model for me. And most especially to my wife – my companion and supporter, even when I sometimes become consumed by my “Projects,” such as this one. To all of you, Thanks!
W. Philip Wagner – Shelburne, Vermont September 2026