Friday, August 29, 2008

The Permian Extinction

If you're like me you have to find the long, painful history of the earth absolutely fascinating. I live in New Mexico and something that is great is an area called Ghost Ranch. Located near a tiny town called Abiquiu (ab-eh-Q), its situated among one of the most bizarre landscapes in the world. Consisting of small mountains, the area has suffered complete erosion to the delight of geologists. The layers of rock from every geological era are completely exposed, giving the landscape a painted layered look, with bands of pink, gold, tan, and dark grayish colored. The banded colors of the rocks and high levels of erosion make the area seem infused with mystery.

The gold rock represents a time when New Mexico was like the Sahara desert. The gray rock, on the other hand, which is on top of the mountains is from an era when New Mexico was actually under water. The state was covered by a large sea. Look at the gray rock up close and its full of fossils of sea creatures. A little museum in Ghost Ranch has a chunk of it you can examine up close.

Once filled with roving bands of dinosaurs, Native Americans called the region home for centuries before the Europeans came. A museum at the ranch tells a little bit of their story with such fascinating objects as a knife that was found embedded in a skeleton, believed to be from someone who lived in the 12th century. Archeologists figured out that the person was killed in a raid over food. The area is high desert and food was often scarce. Drive through there now and you can see why. It must have been kind of magical though, living in an area like that prior to modern civilization and the arrival of the Europeans.

Anyway I digress. The differing geologic eras etched in the rock include the Permian, the era that preceded the arrival of the dinosaurs, which figure so highly at Ghost Ranch. A great extinction occurred that allowed the dinosaurs to come into existence and flourish, its called the Permian extinction.

Unlike the meteor that killed off the dinosaurs, the reason for the Permian extinction is unclear. One theory that had a lot of supporters was that oxygen levels somehow dropped suddenly (volcanoes maybe?) killing off large swaths of life. That sounds kind of hokey to me, but its not like I have any better ideas. But so much for the hypothesis anyway. Recent research seems to discount the idea. So its back to the drawing board. The Permian extinction was so long ago maybe its going to be a lot harder to resolve than the dinosaur extinction. Or maybe they will never figure it out.

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