Thursday, August 11, 2016

St Paul Mammoths Went Extinct 5,600 Years ago

While the Minoan culture on Crete was just beginning, woolly mammoths were disappearing from St. Paul Island, Alaska, according to an international team of scientists who have dated this extinction to 5,600 years ago.

"It's amazing that everything turned out so precisely with dating of extinction at 5,600 plus or minus 100 years," said Russell Graham, professor of geosciences, Penn State."

St. Paul Island lies about 400 miles north of the Aleutian Islands and was part of the Bering Land Bridge before sea level rose when the last glacial period ended. Previous researchers radiocarbon-dated remains of five mammoths to about 6,480 years ago, but there was no way to know if these were the last five animals.

The researchers used a variety of proxies to date the demise of the mammoths on the island. Proxies are things in the environment that can be used to independently document the presence of an organism, even though they are not parts of it. In this study, three different spores from fungi that grow on large animal dung were extracted from lake cores and used to determine when the mammoths were no longer on the island. Proxies in sediments from cores from a lake near the cave were used to determine the time of the demise of the mammoth population.

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