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Tuesday, 05 June 2018 12:30

''Snowball Earth'' triggered by the advent of plate tectonics?

'Snowball Earth'' resulted from plate tectonics 'Snowball Earth'' resulted from plate tectonics.

During the Neoproterozoic, a geological era which occurred about 542 million to one billion years ago, Earth experienced unusual episodes of global cooling that geologists refer to as ''Snowball Earth''.

Scientists usually place the start of plate tectonics at about 3 billion years ago but a team of geologists at the University of Texas at Dallas and Austin has put forward an intriguing new hypothesis that links the dawn of plate tectonics with ''Snowball Earth''. The research was published in the journal Terra Nova (document attached).

Plate tectonics is a fundamental theory formulated in the late 1960 stating that the Earth's crust and upper mantle are made up of distinct pieces that move slowly and independently, creating and destroying landforms and producing volcanoes and large earthquakes. Earth is the only planet with plate tectonics in our solar system. Dr. Robert Stern, professor of geosciences in UT Dallas' School of Natural Sciences and Mathematics, and co-author of the study states: "It is much more common for planets to have an outer solid shell that is not fragmented, which is known as 'single lid tectonics' ". Geoscientists disagree about the time Earth changed from single lid to plate tectonics, with the procedure including the consecutive plate fragmenting to the present global system of seven major and many smaller plates. Dr. Stern highlights geological and theoretical evidence that plate tectonics began between 800 million and 600 million years ago. 

In the study, Professor Stern and his colleague, Dr. Nathaniel Miller of the University of Texas at Austin, suggest that the onset of plate tectonics likely initiated the changes on Earth's surface that led to 'Snowball Earth.' They claim that plate tectonics is the event that can explain 22 theories that other scientists have advanced as triggers of the Neoproterozoic Snowball Earth. "We went through the literature and examined all the mechanisms that have been put forward for Snowball Earth. 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. He also stated: "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. It's an argument that, to our knowledge, hasn't yet been considered. In the present day, climate is in the news because we're changing it by putting more carbon dioxide into the atmosphere. But imagine a time when Earth didn't have plate tectonics, and it then evolved to have plate tectonics-that would have been a major shift in the Earth's operating system, and it would have had a huge effect on climate, too."

Sources: Sci-news.com Sciencedaily.com

Read 305 times Last modified on Tuesday, 05 June 2018 15:25

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