extrusive rock

Extrusive rocks which fall in this category are called basalts.

One type smoothly grades into the next; intrusive and extrusive rock.

The crystals are usually larger than in extrusive rocks.

Please click on the rock type you are interested in to learn more about the important extrusive rocks listed below.

It is an extrusive rock that is very resistant to erosion.

Because extrusive rocks make contact with the atmosphere they cool quickly, so the minerals do not have time to form large crystals.

If the magma erupts on the surface, it produces extrusive rocks.

Extrusive rock is an igneous rock that has erupted onto the Earth's surface.

The extrusive rock is composed of breccia and conglomerate.

Magma type refers to colour of extrusive rocks (light to dark) with increasing SiO2 %.

Extrusive rock is produced in the following proportions:

Extrusive rock of same general composition as andesite, but a less calcic feldspar.

This suggests that these intrusive and extrusive rocks are coeval and share a common source.

Extrusive rocks are fine-grained in texture and crystallise quickly from lava on or near the earth's surface.

Extrusive rocks also have some distinguishing textures.

Both intrusive and extrusive rocks are classed as igneous rocks.

He was distinguished for his researches on extrusive rocks and their microscopic structure and origins.

Over large areas extrusive rocks lie in flat undisturbed piles on a Tertiary surface of moderate relief.

The volume of extrusive rock erupted annually by volcanoes varies with plate tectonic setting.

Both diamond-bearing intrusive and extrusive rocks host significant proportions of fragments generally derived from the local country rock.

Extrusive rocks are fine-grained, as they cool quickly when they are suddenly erupted at the surface.

In general, extrusive rocks have a finer grained texture than intrusive rocks.

The sulfur contents of 299 ocean floor basalts and 68 sub-aerial or shallow water extrusive rocks are also reported.

For a more detailed description of important textures to look for in these extrusive rocks, refer to the attached handout.

In contrast, an extrusion consists of extrusive rock; rock formed above the surface of the crust.