Posts Tagged ‘limestone’
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Earth experienced its biggest mass extinction 250 million years ago. New evidence from Stanford, which looks at calcium isotopes, suggests massive volcanic eruptions were to blame for ocean acidification that wiped out 90 percent of of marine species and about three-quarters of land species. The result may parallel today’s climate change and ocean acidification. Above, geologists examining the Permian-Triassic boundary in the field on the Great Bank of Guizhou in southeast China. (Credit: Jonathan Payne)
STANFORD (US)—New evidence uncovered by analyzing calcium embedded in Chinese limestone suggests that volcanoes, which spewed massive amounts of carbon dioxide into the atmosphere for a million years, caused the biggest mass extinction on Earth. Continue…
Wednesday, April 28, 2010 12:00 - 1 Comment
Science & Technology - Dec 14, 2009 12:26 - 2 Comments
How ho-hum crystals turn into shells
CORNELL (US)—Single crystals of the mineral calcite—the chief material in limestone—are predictable, homogeneous, and, well, a little boring. (more…)
Earth & Environment - Aug 10, 2009 4:00 - 0 Comments
In African rocks, traces of evolutionary blast
UNC marine geologist Justin Ries in the Zebra River Valley, southern Namibia. The Nama Group carbonates, which contain sulfur isotopic signatures suggesting that low marine sulfate and low atmospheric oxygen conditions persisted up until the Cambrian Explosion, loom in the background. (Credit: Gordon Love)
