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 ...

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 ...

At some point around 1 billion years ago, a titanic rift in the Earth’s crust threatened to create a new ocean. It thrust magma upwards across various parallel fractures, some of which would ...

Following a short break for the July 4th holiday, Perseverance drove westward to a site called "Westport," where the clay-bearing "Krokodillen" unit meets an olivine-bearing rock formation. It is ...