Pumice is an example of extrusive igneous rock. The word extrusive means that the magma was forced onto the earth's surface and cooled in a matter of hours. Granite is an example of intrusive igneous ...

Sedimentary rocks are made up of pieces of older rocks (igneous, metamorphic, and sedimentary) and organic remains (shells, bone, etc.). When rocks break apart from erosion they are transported by ...

Introduction -- Physical properties of magma -- Intrusion of magma -- Forms of igneous bodies -- Cooling of igneous bodies and other diffusion processes -- Classification of igneous rocks -- ...

Igneous rock Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as ...

Geology often gets a bad rap as the boring study of rocks and minerals. I’m hear to show you otherwise. Geology is a high-octane window into Earth’s vibrant, often violent history. Every rock tells a ...

During the nearly 14 months that it has spent on the red planet, Curiosity, the Mars Science Laboratory (MSL) rover, has scooped soil, drilled rocks, and analyzed samples by exposing them to laser ...

In my last column, I wrote about the locations where you can find igneous rocks that were formed from lava. The metarhyolite and metabasalt described in the column are known as extrusive rocks, those ...

Igneous rocks are rebels. Sedimentary rocks follow straight-forward rules—they are deposited in horizontal layers, with the oldest sediments on the bottom. Igneous rocks can do what they want. Molten ...

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American The Permian-Triassic boundary (251 million ...

PROF. DALY is a man of ideas. A few facts observed in the field suggest to him a hypothesis which he then proceeds to test by searching for other facts which must exist if the hypothesis be of any ...