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 ...

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 ...

All the rocks in the world are mainly classified into three types: Sedimentary, Igneous and Metamorphic. Igneous and sedimentary rocks are largely prevalent in the world. Here are few interesting ...

There are three types of rock found on Earth. These are igneous, metamorphic and sedimentary. Each rock type is formed in a different way. For example, the rock malachite is mostly made of the ...

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 ...

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. 39, No. 1 (Jan. - Feb., 1931), pp. 54-67 (14 pages) Some rock series cannot be properly classified either as alkalic or as sub-alkalic. To meet this situation a simple ...

Researchers compiled previously published thorium-uranium ratios (Th/U) of more than 29,000 igneous rocks spanning the past 3 billion years and report 2 dramatic decreases occurring at approximately 2 ...

The Journal of Geology, Vol. 70, No. 2 (Mar., 1962), pp. 168-181 (14 pages) Iron-titanium oxides in the compositional range magnetite-ulvospinel-ilmenite are likely to undergo oxidation during cooling ...