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 Pleistocene glacial geology, specifically including Vermont. Unfortunately, that research, which extended from the Quebec border to Middlebury in the Champlain Valley and from Lake Champlain on the west into the Green Mountains on the east, failed to definitively establish the deglacial history of this region. 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.
Thanks to LiDAR and other new technologies, much more information is now available. I think of this information as like pieces in a gigantic, three dimensional spatial puzzle, in which time, representing the deglacial history element, is also a puzzling part. This is complex, especially given that many of the puzzle pieces are missing, and some require study as to how they were formed by the ice sheet or meltwater. The study of deglacial history is a process of fact finding and interpretation, the basic scientific process of hypothesis formulation and testing. When this works, which is not always the case, this can be great fun. And in fact my return to my academic roots has been quite enjoyable.
In this report, I refer to “paradigms,” which are powerful ways of processing information, at the very heart of human thinking. But at times they limit our ability to see and understand what is before our eyes. It turns out that satisfying my curiosity required imagination to explore new paradigms, 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, for me, relevant 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.
It turns out that the puzzle-picture coming from this study is new and different. Many puzzle pieces have fallen into place, painting a very different deglacial history than previously understood. This required serious effort on my part, and some fresh thinking.
As discussed in this report, this study examined deglacial history by the exploration of three elements, which have been inspired by Quebec research specifically:
- A “Bath Tub Model,” in which elevation serves as a guide to correlate ice margins across the State.
- “Styles,” a term referring to the environmental conditions along these ice margins;
- “Glacial Dynamics,” the interaction between the ice sheet and its environmental setting, especially physiography and ponded water.
This report examines and tests the Bath Tub Model hypothesis, exploring the thesis that ice margin features which occurred late in deglacial history when the ice sheet had become thinned were influenced or controlled by physiography, and thus can be correlated so as to enable the determination of deglacial history of Vermont on a statewide basis by usage of ice margin feature elevations.
Together these three elements have helped me paint a new picture of deglacial history for the entire State of Vermont, with suggested correlations in neighboring regions. The deglacial history being reported here is late in deglacial history, not the full deglacial history dating back to the time when the ice sheet first began to recede from its maximum. As deglaciation proceeded, the earliest evidence in Vermont was associated with the emergence of mountain tops in what is referred to herein as the “Nunatak Phase.” Evidence for this Phase is recorded by mappable ice margin features, but these are not correlated because at this early time the ice thicknesses were too substantial, with ice margins only grossly related to physiography. In the following “Lobate Phase,” however, the ice thickness had sufficiently diminished relative to physiographic relief, such that ice margins can be identified and correlated across the entire State. This correlation indicates that the moraines in Quebec near the Vermont border represent most of the entire history being reported here, meaning that this report is actually documenting only a portion of a late phase of the entire deglacial history, ending when the last ice margin marked the final exit.
The Styles concept leads to the recognition that the environmental conditions along the ice margin were an important part of the deglacial history story. For example, I repeatedly refer to ice sheet step-down recession being likened to “multiple rings on a slowly draining bath tub.” In fact these rings are comprised not just by ice margin features but as well by associated drainage and standing water features. And further these environmental conditions were not just bystanders but in fact largely influenced the ice sheet, both controlling the ice margin as a Glacial Dynamic (thereby strengthening the case for the Bath Tub Model) and as well destabilizing the margins, including by calving. This makes my findings much more important, being not just about deglacial history but as well pertaining to the issue of modern day global warming. In fact, the story revealed here indicates that the deglacial history of Vermont has very significant implications for modern day concerns about global warming and its impact on present ice sheets and glaciers, which is briefly examined.
Now, finally, for me personally, the many puzzle pieces seem to have come together remarkably well, telling an intriguing story. As just stated, I looked at this just for the fun of it, the development of new hypotheses, and the joy when sometimes these are confirmed. At this point, I have satisfied my curiosity. I finally have reached a better understanding of this history.
Although the history story I developed, as reported here, is one of relative differences in age, as opposed to absolute differences giving actual numbers, the evidence from the works of others suggest that generally speaking this deglacial history is very young, taking place only about 10,000 – 15,000 years ago. A few years ago I worked on my family history, taking me back about a thousand years, about 20 generations. This gives me a sense and puts into better perspective the time when the ice sheet was here, which is geological, but actually not that long ago. Geologically speaking, these events happened “yesterday.” Vermont mountain peaks had begun to emerge from beneath the ice sheet as nunataks, and the ice sheet was becoming thinner, developing lobes in the major physiographic basin, with ice margins receding generally northward, fronted by large bodies of water. This is the history explored in this report.
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 the job is not yet finished, the general sense of Vermont deglacial history in a regional context is emerging. My fundamental interest in this endeavor was to satisfy my curiosity, for myself. My curiosity is now satisfied, and I am happy to leave it to others to continue with the exploration and refining of this history. Hopefully my findings may provide insights for future research, because more work certainly needs to be done. I see this report as a guide, helping to give a direction to future research.
The deglacial history of Vermont has turned out to be quite complex, and this complexity has made this a more difficult report both to think through and to write. 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 – 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 remains imperfect. In general, thinking through and writing this report was, has been, and continues to be a challenge which again is as yet imperfect. I fundamentally like to write, which for me is a way of thinking. And this history has taken a lot of thought.
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. However, traditional academic publishing is not my interest or goal. I have decided to present my findings as a web site, given here as VermontDeglacialHistory.org. My purpose here 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 the story.
My preference at an early time in this work was to somehow find a way for this to be a collaborative venture with others who have been toiling over these issues, in some cases since the time I left academia in 1980. With this in mind, I shared early drafts with present day researchers. I intentionally avoided inclusion of many previously published works, so as to be respectful and not tread on the toes of others. Unfortunately, this backfired, perhaps giving the impression that I was not aware, mindful, or respectful of their work. I very much regret this outcome, as I believe the end result would have been much better with collaborative thinking and input. This report has grown so large, that it has become difficult for me to see it with fresh eyes, which could have come from others.
Again I want to emphasize that I do not see this exploration of Vermont deglacial history as merely an academic matter, but rather as bearing on present day concerns about global warming, which for me makes this enterprise more serious. The issue of global warming is identified in many places in this report. I have added brief comment about what I believe the story about the recession of the Pleistocene Laurentide ice sheet in Vermont, as given here, may tell us about critical issues for global warming and its impact on modern ice sheets, in particular the Greenland ice sheet which I see as especially vulnerable. I don’t claim to be an expert on global warming, but that doesn’t stop me from thinking about my grandkids’ well-being. In my opinion, the Vermont deglacial history presented here has as much to say about modern day global warming, ice sheet instability, and sea level rise, as it does about past history itself.
I am aware that this report could be substantially improved by both further research and more careful editing. I know that this report continues to include awkward and even incorrect phrasing and grammar. I have tried to make it better, but this is a big job. “This ain’t purfect,” as my grandmother used to say about the quilts she used to patch together. I am an old dude who likes to bike ride and hike, and this report keeps getting in my way. My apologies to the reader for mechanical errors, typos, mis-spellings, redundancies, etc. Further, I am aware that the present draft contains numerous redundant discussions. 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! Also, I suspect that this report likely contains technical or scientific errors, hopefully minor, but I acknowledge room for improvement. In fact, my primary goal is to encourage further research by others, using my ideas, likely with modification, to reach a better understanding. Again, this is complex stuff. My goal is to make the information I learned available as best I can, as soon as possible, in a limited amount of time, in a reasonably good form, so that I can get back to hiking, biking, painting, and other life pleasures with family and friends. I appreciate your patience and indulgence.
Finally, an expression of gratitude. To my son –a health economist at Stanford and the VA- 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 have become consumed by my Projects, such as this one… To all of you thanks!