What is the slowest moving tectonic plate

The possible cause of sudden tectonic plate movements

Research led by Yale University may have solved one of the greatest mysteries in geology. Why do underground tectonic plates sometimes move abruptly, even though they typically shift over tens of millions to hundreds of millions of years?

According to a new study published January 19, 2015 in the Journal Proceedings of the National Academy of Sciences published, the answer lies in two things: thick crust plugs and weakened mineral granules. When these effects work together, they could explain a number of relatively rapid movements in tectonic plates around the world, from Hawaii to East Timor. Of course, the term “fast” in this case still means periods of a million years or more.

"What probably makes our planet so special is the fact that it has plate tectonics," said Yale University geophysicist David Bercovici, lead author of the study. “Our work here looks at the evolution of plate tectonics. How and why do the plates change their directions over time? "

In the traditional view, scientists assumed that all tectonic plates are drawn from subducted fragments. This results from the fact that the cooler, upper layer of the earth's rock surface becomes heavy and slowly sinks into the deeper mantle. Even so, this process is out of the question for sudden plate shifts. Such abrupt movements require the sections to detach from their plates, but rapid detachment is difficult because the sections should be too cold and too stiff for this.

According to the Yale study, there are additional factors at work. Thick crust from continents or oceanic plateaus is brought into the subduction zone, clogs it and causes the section to break off. The detachment process is accelerated when mineral granules begin to shrink in the section, which results in a rapid weakening of the section.

The result is that tectonic plateaus abruptly shift horizontally or continents suddenly rise. "Understanding this helps us understand how the tectonic plates have changed over the course of Earth's history," said Bercovici. "It complements our knowledge of the development of our planet, including its climate and biosphere."

The co-authors of the study are Gerald Schubert from the University of California at Los Angeles and Yanick Ricard from the Université de Lyon in France.

Source: http://news.yale.edu/2015/01/19/geophysicists-find-crusty-culprits-behind-sudden-tectonic-plate-movements

(THK)