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“But nature itself is wild, indifferent, and accidental; it is a ceaseless pullulation and unfolding, a dense evolutionary plasma of perpetual differentiation and innovation.” – Sanford Kwinter, Architectures of Time
remnant of the Champlain Sea, July 2010
In 1999, thirty miles northeast of Burlington, Vermont, in a small town called Jeffersonville, contemporary life collided with the sediments of an ancient Pleistocene Sea. Solid ground liquified, unleashing a landslide that displaced over 27,000 cubic meters of Pleistocene materiality. In such moments, time seems to undergo a break or experience a ripple in its linear flow. Geologic forces of the “past” surge forward into “now.” Resurfacing as material, they become vividly “present.” Suddenly, we humans of today find ourselves living contemporaneously with geologic worlds that preceded us.
site of the Jeffersonville slide, FOP 2010
People living in proximity to the Jeffersonville slide, for example, are living contemporaneously with the Champlain Sea – an extensive body of water that was once an inlet of the Atlantic Ocean. The Champlain Sea covered parts of Quebec, Ontario, Vermont and New York State 10,000 years ago.
map by Northern Cartographic, from the Lake Champlain Basin Atlas
A Pleistocene history of the Champlain Sea reads:
“Approximately 10,000 years ago, the glacier’s retreat allowed marine waters from the St. Lawrence estuary to flood the Basin, forming the Champlain Sea, an arm of the Atlantic Ocean. The extent of this salty sea is shown on the Champlain Sea Map [182 KB]. Many marine animals, including Beluga whales, Atlantic cod, seals, and blue mussels lived in the Champlain Sea. In 1849, railroad workers found a Beluga whale skeleton in Charlotte, VT, which is now on display at the University of Vermont. Many other fossils of the Champlain Sea time period have been found in Canada.
Removal of the glacial ice, which was extremely heavy, allowed the earth’s surface to rebound. This rebound cut off the supply of salt water. The Champlain Sea gradually changed back into freshwater from rainfall, creating present day freshwater Lake Champlain, which has existed for about 9,000 years. The Basin is rimmed with sand and gravel deposits which record the shorelines and deltas of both Lake Vermont and the Champlain Sea”. -Lake Champlain Basin Atlas
shores of Lake Champlain, the contemporary remnant of the Champlain Sea, 2010
Earlier this month, while chasing the Pleistocene around Lake Champlain, FOP visited the site of the Jeffersonville, VT landslide. We wanted to take a closer look at the materiality that ancient Champlain Sea presents to us today. The Sea’s sediments have peculiar properties that can trigger time’s slippage within itself. Sometimes, one slip brings 10,000 years forward into the present in an instant.
unstable, sandy sediments of the Champlain Sea, found at the site of the Jeffersonville landslide
Landslides are far from uncommon in the Champlain Sea Basin north of Jeffersonville. There, the Sea left an even more volatile material in its wake. Leda clay, or “quick clay,” is known for its geologically unstable properties and an unnerving ability to liquify instantaneously.
“Leda clay slopes in the Ottawa valley are vulnerable to catastrophic landslides. More than 250 landslides, historical and ancient, large and small, have been identified within 60 km of Ottawa. Some of these landslides caused deaths, injuries, and property damage, and their impact extended far beyond the site of the original failure. In spectacular flowslides, the sediment underlying large areas of flat land adjacent to unstable slopes liquefies. The debris may flow up to several kilometres, damming rivers and causing flooding, siltation, and water-quality problems or damaging infrastructure. Geologists and geotechnical engineers can identify potential landslide areas, and appropriate land-use zoning and protective engineering works can reduce the risk to property and people.”
Yet, the Canadian Encyclopedia adds to its entry on the Champlain Sea, “When properly drained, its marine clays constitute the best agricultural land in Québec.”
Landslide map of Leda clay in Canada, from Natural Resources Canada
In May of this year, a family of four perished in St. Jude, Quebec (about 50 miles northeast of Montreal) when the Leda clay beneath their house gave way. The resulting landslide created a hole 100 feet deep, 300 yards wide and a third of a mile long.
In the United States, the ancient Champlain Sea continues to destabilize the present. More than 10 years after the Jeffersonville landslide, its site is still closely monitored by geologists because of its threat to the surrounding village, especially its elementary school. The “Progress Report for Geotechnical Study of the Jeffersonville Landslide, Northwestern Vermont” (published in 2009) can be read here.
view from the top of Deer Run Heights, site of the 1999 Jeffersonville landslide
view from below the slide
traces of the slide from above, ten+ years later
“Despite the fact that we experience it as immutable, the land we inhabit is inherently unstable. It is the very ability of the land to change both instantly and cataclysmically through earthquakes, volcanoes, floods or storms, and its gradual transformations through sedimentation and erosion, that creates the differential- the change in elevation, material and direction- producing the riches we mine to create what we think of as changeable culture.” – Aaron Betsky, “Instability” from Landscape + 100 words to inhabit it
We parked and walked through the brush to the still raw edge of the Jeffersonville slide. At the boundary of the ridge we were struck with a realization that what appeared to be solid ground was actually quite unstable- and was a relatively recent deposit of the ancient waters of the Champlain Sea. We completed our work at a rapid pace and left with an embodied sense that though time and geologic materiality are products of one another, they are not bound to stable, or mutual, rates of unfolding. The sediments of the Champlain Sea remind us of our ongoing challenge to find ways for human designs and infrastructures to respond dynamically to the unpredictable moments of slippage when geologic forces will inevitably cascade into our present.
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