Tuesday, May 08, 2007

Cryogenian Theory on Ice?

The "Snowball Earth" theory has been challenged by new evidence from Oman.

The research team measured the amount of water-induced weathering in sedimentary rocks from Oman.

The results, described in the April issue of Geology magazine, indicate that the Cryogenian climate swung several times between warm-wet and dry-cold, which the authors say is inconsistent with a deep freeze.

"Although [Snowball Earth] is a great idea, I am convinced it didn't happen," [Phillip] Allen said.

Previous work has discovered other problems with the theory, Allen continued.

For example, wave ripples in sandstone from the same period could only have formed in the presence of open water.

There is also no evidence for the big chill causing any mass extinctions.

Ocean-bound microorganisms, which were the dominant life forms back then, "carried on more or less business as usual," Allen said.

I still think the idea is neat, even if it can be demonstrated to be not well supported.

No comments:

Post a Comment