July 28, 2009
oldest known fossils found in lake
The oldest known fossils — microscopic embryos with no adult specimens — have been found in lake, rather than marine, sediment.
“It is most unexpected that these first fossils do not come from marine sediments,” said researcher Martin Kennedy, a geologist at the University of California at Riverside.
“Lakes are typically short-lived features on the Earth’s surface, and they are not nearly as consistent environments as oceans are,” he explained. “So it’s surprising that the first evidence of animals we find is associated with lakes, which are far more variable environments than the ocean. You’d expect the first appearance of animals to be in the most conservative, stable environments we could imagine.”
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