The Evolution of Lake Champlain Basin A billion years ago, Lake Champlain and all of North America was covered by huge glaciers. The air was rich in oxygen because of photosynthesis done by plants. The Adirondacks Mountains Mountain-building events made the then 20, 000 feet Adirondack Mountains. Minerals such as garnet, anorthosite, and diopside came from metamorphic rocks. The Iapetus Ocean What is now the Champlain Valley started to rift 600 million years ago.
It turned into the Iapetus Ocean with rapidly evolving life including trilobites, cephalopods, bryozoans, gastropods, and primitive corals. The Green Mountains The Iapetus Ocean closes completely and the land masses on both sides collide, forming the Green Mountains. One theory that explains why theyre called that is because of a mineral called chlorite on the rocks. The Champlain Thrust The Champlain Thrust is a huge slice of a rock that broke free and was forced upward above younger rocks during the formation of the Green Mountains.
The Great Hiatus The Great Hiatus was the period between the formation of the Green Mountains 400 million years ago and the recent glaciation. We know little about the time, but we do know that a lot of erosion was going on and low rounded hills formed over the surface in the Champlain Valley. The Brandon Lignite The Brandon Lignite is a large deposit of iron-rich clay and lignite. Scientists think the area was much warmer 25 million years ago because they found the remains of plant seeds and fruit. Plate Tectonics.
Plate tectonics is the study of the folding and faulting of the earth's crust. When the earths plates move, they can create earthquakes or leave depressions in the earth that fill with sea water. The Pleistocene - The Age of Glaciers The Pleistocene Period lasted from 2. 5 million year ago to about 10, 000 years ago.
The Champlain Basin was heavily affected by glaciers, especially in the valley between the Adirondacks and the Green Mountains. Lake Vermont Lake Vermont was formed by meltwater that flooded the land at the bases of the glaciers that were melting 20, 000 years ago. The meltwater was blocked by the north and south and Lake Vermont. The Champlain Sea About 13, 000 years ago, a lot of ice melted and land in New York and Vermont was exposed again. Most of Lake Vermont drained because the ice around it melted too.
The weight of the glaciers had made the land under the sea lower and this was quickly flooded by the rising sea. Now Lake Vermont was more like a large inland bay instead of a freshwater lake. Around this time the first humans appeared. Lake Champlain About 9, 000 years ago, the surface of the Champlain Sea rose until it was higher than sea level.
This caused some of the water to flow to the valley of the St. Lawrence and back. Then the rivers around Champlain Sea flushed it with freshwater, the Champlain Sea turned into Lake Champlain. The Fossil History of the Lake Champlain Basin Fossils are created when a bone, tooth, or plant fiber gets replaced by rock material. This usually happens when the original material is protected in soft sand or sand. The Earliest Fossils Fossils of trilobites, cephalopods, gastropods, bryozoans, and graptolite's have been found in the Iapetus Ocean that existed 450 million years ago.
Pleistocene Fossils Numerous mammoth, caribou, fox, and deer fossils have been found in New York and Vermont. This would mean that these animals once lived in that area. The Charlotte Whale In 1849, a Beluga whale was found by a railroad near Charlotte. The interesting thing about this was that it was found hundreds of miles away from the nearest ocean.
We now know that whales swam in the Champlain Sea and were buried in sediment when they died. The Champlain Sea now exists as Lake Champlain.