Does andesite cool slowly or fast?

Does andesite cool slowly or fast?

Porphyritic texture — andesite: This is an extrusive igneous rock. The magma from which it formed cooled slowly for a while deep below the surface (forming the large crystals), then finished cooling very quickly when it was ejected at the surface, forming the fine-grained groundmass.

What is the cooling history of andesite?

Andesite is a volcanic rock. It is fine-grained because it forms by the rapid cooling of magmas usually when it erupts onto the Earth’s surface and forms lava flows. Andesite forms from magma that contains less quartz (silica) than rhyolite but more than basalt.

What is the temperature of andesite?

between 900 and 1100 ° C.
Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100 ° C.

What rock that has cooled fast may look like glass?

obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass.

How fast does andesite magma flow?

Andesitic lava is viscous, compared to basaltic lava. Andesitic lava flows at a rate of a few kilometers per hour, whereas basaltic lava can flow up to 10 km/h. Because of their viscosity, andesitic lavas “rarely extend beyound 8 km from their vents”.

Which rock crystallizes at the highest temperature?

A study of the whole series of rocks between rhyolite and basalt leads to the inevitable conclusion that rhyolite or granite crystallize at the lowest temperature of the group and that quartz latite or granodiorite, andesite or diorite, and basalt or gabbro crystallize at successively higher temperatures.

What kind of igneous rock cools slowly?

Intrusive rocks
Intrusive rocks, also called plutonic rocks, cool slowly without ever reaching the surface. They have large crystals that are usually visible without a microscope.

Is andesite intrusive or extrusive?

Andesite is an extrusive rock intermediate in composition between rhyolite and basalt.

How fast does obsidian cool?

Obsidian: Those rocks are intrusive. They cool slowly underground, so they have thousands of years to form crystals. With so many crystals, they can’t be shiny glass like me.

Is andesite extrusive or intrusive?

What is the temperature of andesitic magma?

about 800oC to 1000oC
Andesitic magma has moderate amounts of these minerals, with a temperature range from about 800oC to 1000oC (1472oF to 1832oF).

How does andesitic lava flow?

lava. Lavas of andesitic or intermediate composition commonly form a somewhat different type of flow, known as a block lava flow. These resemble aa in having tops consisting largely of loose rubble, but the fragments are more regular in shape, most of them polygons with fairly smooth sides.…

Which mineral has the lowest temperature of crystallization?

minerals that crystallize at the lowest temperatures (quartz, muscovite, alkali feldspar) are rich in Si and Al; rocks that contain these minerals are felsic in composition (granite, rhyolite). rocks with intermediate minerals (amphibole, biotite) are intermediate in composition (andesite, dacite, diorite).

What type of rock is cool?

Extrusive Igneous Rocks: The magma, called lava when molten rock erupts on the surface, cools and solidifies almost instantly when it is exposed to the relatively cool temperature of the atmosphere.

What is the characteristics of andesite?

Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava. The mineral composition of andesite includes biotite, pyroxene, or amphibole.

What is the hardness of andesite?

7
The hardness of andesite rocks on the Moh scale is 7.