This week...another photo from Chile. Here we got a good ol' geologic puzzle...the kind you'd learn in an intro class. Here we can use the intuitive law of cross ...

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 ...

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

THE potential of the potassium–argon technique in the dating of young rocks can be evaluated by applying it to intrusive igneous rocks which are well dated by conventional geological methods. Because ...

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 ...

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 ...

When driving from Malvern to Hot Springs on U.S. 270, I often take a short detour through one of the most interesting and unusual places in the state: Magnet Cove. Geologist Michael J. Howard has ...

With house-size boulders tumbled across its scarred surface and slanted, twisted peaks looming over its iconic namesake trees, Joshua Tree National Park’s preternatural terrain evokes extraterrestrial ...

Scientists on NASA's Perseverance mission made a surprising discovery about the composition of rock in Jezero Crater, one that will help them get a better idea of when water existed on Mars, and ...

The Journal of Geology, Vol. 40, No. 2 (Feb. - Mar., 1932), pp. 119-139 (21 pages) A restudy, with more ample descriptions than previously published. New interpretations are that the fragmental ...

Pockets of microbes have been found living within a sealed fracture in 2-billion-year-old rock. The rock was excavated from the Bushveld Igneous Complex in South Africa, an area known for its rich ore ...