Some volcanic points have a shallow heat source

The major part of volcanic activities of the Earth come from the tectonic plates of the earth’s crust. To do this, different materials from the depths come into fusion. They then rise to the surface. This is particularly the case for the hottest spots. However, all volcanic points do not come from deep mantles. In fact, some geological mechanisms are close to the Earth’s surface.

The hot spots the coldest are fed by a fusion of materials far from the earth’s crusts. This is the result of a study conducted by Xiyuan Bao, a geophysicist at UCLA. It was published in the American journal Science.

This volcanic activity unusual is found in various regions of the globe. One can quote as examples the volcanoes of the islands of Hawaii, that of the Ascension in the South Atlantic or those of the Pitcairn Islands of the South Pacific.

Where do volcanoes come from?

A classic theory dominates the scientific world regarding volcanoes. It was the only known theory until this recent study. According to her, there is only one type of volcano. The latter comes from the plume of materials in the tectonic plates. The process begins with the convergence of the different materials. The mantle of the planet then allows them a wide circulation.

This is the dominant type. Their degrees of heat are quite high, as they are fed by the deep layers of the mantle.

The second type of volcano comes in the form of hot spots. This is the hypothesis of the UCLA scientists. Unlike the first, their intraplates are isolated. This is why their heats vary according to their depths. The study therefore concluded that some volcanic points have a lower temperature than others.

Heat buildup in the crust could then lead to local melting of carbonate-rich rocks that could fuel volcanism. »

Fitton, one of the team’s scientists

A game-changing study

In order to conduct their studies, they traveled to ocean areas. First, they delimited their objects of study. In total, 26 volcanic points have been counted. Besides, scientists started with the hypothesis of their new theories. Indeed, they considered from the start that some of these volcanic points were fed by shallow material. As a result, their heat levels did not match normal.

To do this, seismic data were used to compare the different temperature levels. In order to obtain this data, they conducted the study on different depth scales. The distance examined underground varied from 260km to 600km. Thus, the results turned out to be positive.

First, 12 hotspots exhibited a temperature of 1388° Celsius or 2530° Fahrenheit. Next, 10 more hotspots had a lower temperature than the first ones. However, the study showed that they were 50° C and 135° hotter than certain volcanic points. In final, 4 volcanic points present 36° C less than the previous category.

“This study helps to determine which volcanic plumes are deep and which are not. »

Keith Putirka, petrologist at California State University

SOURCE: SCIENCE NEWS

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