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A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards. [1] If the magma finds a path to the surface, then the result will be a volcanic eruption ...
Its collapse, due to the eruption of magma emptying the underlying magma chamber, formed a caldera that holds Crater Lake (Giiwas in the Native American language Klamath). [6] Mount Mazama originally had an elevation of 12,000 feet (3,700 m), but following its climactic eruption this was reduced to 8,157 feet (2,486 m).
An analysis of crystals from Yellowstone's lava showed that prior to the last supereruption, the magma chamber underwent a rapid increase in temperature and change in composition. The analysis indicated that Yellowstone's magma reservoir can reach eruptive capacity and trigger a super-eruption within just decades, not centuries as ...
For instance, water causes magma to cool and solidify much more quickly than in a terrestrial eruption, often turning it into volcanic glass. The shapes and textures of lava formed by submarine volcanoes are different from lava erupted on land. Upon contact with water, a solid crust forms around the lava.
The latter estimate published in 2012 is based on argon dating of the first pre-caldera lava flows. [15] The formation of Tambora drained a large magma chamber pre-existing under the mountain. The Mojo islet was formed as part of this geological process in which Saleh Bay first appeared as a sea basin about 25,000 years BP. [7]
It formed out of basaltic magma by fractional crystallization [50] and had a temperature of about 1,000 °C (1,830 °F). [12] Its eruption may have been triggered either by the entry of new magma into the magma chamber or the effects of gas bubble buoyancy. [51]
A crater 0.6 mi (1 km) across and 330 yd (300 m) deep formed out of the rubble. The event involved the movement of 100 million cubic meters of volcanic material . A region of 3.9 to 5.0 sq mi (10 to 13 km 2 ) of the summit was altered and populated by bus-sized pillow lava blocks , precariously perched along the outer rim of the newly formed ...
The Sierra batholith was formed when the Farallon Plate subducted below the North American Plate.The resultant molten rock rose through the Earth's crust over the span of 100 Ma, forming several plutons, or a chain of volcanoes if the magma reached the surface.