Privileged Planet: p;ate tectonics and 'snowball Earth' (Introduction)

by David Turell , Tuesday, May 08, 2018, 01:08 (2392 days ago) @ David Turell

About 700-800 million years ago the Earth was a snowball of ice and snow all over. The start of plate tectonics might have caused it by creating volcanism and blotting out the sun with the eruptions:

https://www.sciencedaily.com/releases/2018/05/180507153141.htm

"Plate tectonics is a theory formulated in the late 1960s that states the Earth's crust and upper mantle -- a layer called the lithosphere -- is broken into moving pieces, or plates. These plates move very slowly -- about as fast as your fingernails and hair grow -- causing earthquakes, mountain ranges and volcanoes.

"Earth is the only body in our solar system known to currently have plate tectonics, where the lithosphere is fragmented like puzzle pieces that move independently," said Dr. Robert Stern, professor of geosciences in UT Dallas' School of Natural Sciences and Mathematics, and co-author of the study, along with Dr. Nathaniel Miller, a research scientist in UT Austin'

"'It is much more common for planets to have an outer solid shell that is not fragmented, which is known as 'single lid tectonics'," Stern said.

"Geoscientists disagree about when the Earth changed from single lid to plate tectonics, with the plate fragmenting from one plate to two plates and so on to the present global system of seven major and many smaller plates. But Stern highlights geological and theoretical evidence that plate tectonics began between 800 million and 600 million years ago, and has published several articles arguing for this timing.

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"'We went through the literature and examined all the mechanisms that have been put forward for Snowball Earth," Stern said. "The start of plate tectonics could be responsible for each of these explanations."

"The onset of plate tectonics should have disturbed the oceans and the atmosphere by redistributing continents, increasing explosive arc volcanism and stimulating mantle plumes, Stern said.

"'The fact that strong climate and oceanographic effects are observed in the Neoproterozoic time is a powerful supporting argument that this is indeed the time of the transition from single lid to plate tectonics," Stern said. "It's an argument that, to our knowledge, hasn't yet been considered."

Comment: This special planet has a moving crust. None of our neighbors have it. It is a requirement for life. Further note how tough life it. It survived the freeze.