Search results
Results from the WOW.Com Content Network
Its high silica content makes rhyolitic magma extremely viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations.
Rhyolitic magma is felsic and the most abundant in silica, potassium, and sodium but the lowest in iron, magnesium, and calcium. [1] [3] The silica composition of rhyolitic magma ranges from 65-75 wt.%. [1] It forms in the lowest temperature range, from about 1200 °F to 1470 °F. [1], [3] Rhyolitic magma has the highest viscosity and gas ...
After the caldera was formed, there were rhyolitic lava flows between 160,000 and 70,000 years ago. [8] The Yellowstone Caldera is a resurgent caldera and has experienced resurgent doming. [8] The Yellowstone Caldera has two resurgent domes formed by magma upwelling called Sour Creek and Mallard Lakes. [8]
The erupted magma was very uniform in composition and this composition has not been seen since, but had been seen before the eruption. [1]: 8 Detailed compositional analysis has revealed the early phases of the eruption had a small amount of magma from outside the Taupō Volcano and are most consistent with a tectonic trigger.
Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from magma (molten rock). [ 1 ] Flow banding is caused by friction of the viscous magma that is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or, if the magma is erupted, the surface of the Earth ...
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in ...
The composition is related to heat and volatiles transferred between the parent basalts and such rhyolites over the time the sub pocket has been maturing. Basaltic-rhyolitic magma interaction definitely happens from local and world wide studies, and will also be a factor in the many different eruption styles that have occurred. [2]
The Bishop Tuff is a high-silicate rhyolitic welded tuff, made up of ash and pumice clasts. The main minerals found in the pumice clasts are biotite, plagioclase, quartz, and sanidine. The main composition is SiO 2 (73.4-77.9%), [3] followed by Al 2 O 3 (12.7%). [7] The Bishop Tuff is compositionally zoned.