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The Oldest ReefIt is found in Quebec |
By Stefan Anitei, Science Editor
26th of October 2006, 07:09 GMT
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Isle La Motte is a 3-by-7-mile island near where Lake Champlain at its northern part empties into the Richelieu River in Quebec.
The half billion years old flat rock slab found in the center of the island is believed to be the world's oldest reef. The now-preserved since 1999 Fisk Quarry exhibits on its walls a vertical stone timeline of fossilized long extinct plants and animals that once roamed in a warm equatorial sea and reached their current northern position as the continents drifted into their present locations.
The 81-acre Goodsell Ridge Fossil Preserve harbor the fossilized remains of nautiloids (the first cephalopods, which today are mostly represented by squids, cuttlefishes and octopuses); stromotoporoids,
a cabbage-like animal that was the primary builder of the reef and represents a fossil group related to current corals; and early snails.
Some fossils are as big as a playing card, others are almost microscopical. "As we walk through the Goodsell Ridge, we'll be able to actually walk across their tops, which would be very similar to what you'd see if you were snorkeling over them 480 million years ago," said Charlotte Mehrtens, chair of the geology department at the University of Vermont.
These rocks are part of a geologic formation that once ran from Newfoundland to Tennessee and Virginia and the area is known as the Chazy Reef. "There is something unique about the environment here in Vermont, where the reef diversity was very high, meaning there are lots of different kinds of organisms, lots of different kinds of species," said Mehrtens.
"On top of that, those species changed over time, so the organisms that built the oldest layers of the reef are different from the organisms that built the middle layers and are different from the organisms that built the youngest layers."
This a perfect example of biological succession, where one species is followed by another during the geological eons.
This reef is unique because "It is the first and most extensive reef that was ever built in the earth's history by the phylum briozoa," said Roger Cuffee, a professor of paleontology at Penn State University.
Briozoas are a line of animals that evolved from soft-bodied animals, and are close to mollusks, not to corals, predating the coral reefs by about 30 million years. "Think miniature coral and think the seacrust crud on shell and rocks growing in shallow water when you wade into tidal pools," Cuffee said.
"It really sort of sparks the wonder and the mystery of things, when you think of something that was alive half a billion years ago, that was alive before there was life on land" Mehrtens said.
In 2005, the Isle La Motte Trust bought the surface of Goodsell Ridge Fossil Preserve, where visitors can tour the reef on mowed trails.
Photo credit: Toby Talbot
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