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Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Harshvardhan Sharma posted an Question
January 21, 2021 • 23:35 pm
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30 points
30 points
- IIT JAM
- Geology (GG)
14.explosive eruptions often involve rhyolitic magmas. this is because of their :
3 Answer(s)
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Sajan sarthak Best Answer
HIGH SILLICA CONTENT AND HIGH GAS CONTENT. Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air. These solid particles become pyroclasts or volcanic ash.
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But isn't Rhyolite associated with High Water content?
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DIRECTLY WE CAN'T SAY THAT...RHYOLITE IS SILLICA RICH FELSIC MAGMA ...AND WATER CONTENT REDUCES THE VISCOSITY ...SO FOR EXPLOSIVE ERUPTION VISCOSITY MUST BE HIGHER THAT'S WHY DID NOT CHOOSE WATER CONTENT
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Sajan sarthak
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HIGH SILLICA CONTENT AND HIGH GAS CONTENT. Explosive eruptions are favored by high gas content & high viscosity magmas (andesitic to rhyolitic magmas). The explosive bursting of bubbles fragments the magma into clots of liquid that cool as they fall through the air. These solid particles become pyroclasts or volcanic ash.
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Saurabh 1![best-answer]()
Correct option would be (A). Explosive eruptions are mostly attributed to felsic magmatism. High silica content leads to silica polymerisation, which in turn increases viscosity of the magma and hence leading to explosive eruption with high gas or volatile content. High pressure in gas bubbles causes the bubbles to burst when reaching the low pressure at the Earth's surface.