How is pumice made

Trapped gases occupy much larger volume than they did when dissolved in magma. Hence, it is perhaps needless to say that it forms as a result of explosive volcanic eruptions. Explosive volcanoes that produce this rock type are predominantly located at the continental margins above subduction zones The Pacific Ring of Fire, for example.

This environment is favorable for this type of volcanism because lava above subduction zones is rich in volatiles gases expand when magma ascends and it is also enriched in material incorporated from the continental crust siliceous mahma is more viscous. This piece of rock from Santorini was thrown out of a volcano approximately years ago during the Minoan eruption. The eruption was one of the most powerful in historic times, 30 cubic kilometers of rocks were ejected from the volcano 1.

The width of the specimen is 40 mm. Phonolitic pumice from Tenerife. Width of sample is 6 cm. A layer of pumice between darker layers of scoria in Tenerife.

Pumice layer is a product of violent Plinian eruption farther away. Because pumice is igneous, it is at times glass-like, and the bubbles are trapped between the thin translucent bubble walls of rock. Depending on the amount of volcanic gases coming from the lava before it cools rapidly, either pumice or scoria can be created. Pumice is a lighter color, has a porosity near 90 percent and is less dense; scoria is denser with larger bubbles and thicker bubble walls and sinks rapidly unlike pumice, which initially floats.

If there are large amounts of gas present, pumice is created; when there is less gas, associated with less viscous magma, scoria is formed. Pumice can be formed rapidly and, in the past, large pumice rafts have been created from underwater volcanic eruptions like during the volcanic activity near Tonga in Collin Fitzsimmons has been writing professionally since , specializing in finance and the stock market.

Fitzsimmons earned a bachelor's degree in economics from the University of Virginia. Pumice, Volcanoes and Density Pumice is a unique rock, noted for its light weight and low density dry pumice can float in water. A List of Extrusive Igneous Rocks. Please be polite, and avoid your passions turning into contempt for others. We may delete posts that are rude or aggressive, or edit posts containing contact details or links to other websites.

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