felsic

[fel-sik]

adjective

Geology.

1. (of rocks) consisting chiefly of feldspars, feldspathoids, quartz, and other light-colored minerals.

felsic

1. Relating to an igneous rock that contains a group of light-colored silicate minerals, including feldspar, feldspathoid, quartz, and muscovite.

2. Compare mafic

Word History and Origins

Origin of felsic¹

First recorded in 1910–15; fel(dspar) + s(ilica) + -ic

Example Sentences

Titanium isotopic evidence for felsic crust and plate tectonics 3.5 billion years ago.

Read more on Nature

One type of magma, called felsic or rhyolitic, is about 65 percent to 75 percent silicon dioxide; its temperature is roughly 1,112 to 1,472 degrees Fahrenheit.

Read more on New York Times

Molten rock that glows red is probably in the felsic temperature range.

Read more on New York Times

Should a volcano erupt, for example, the newly released lava will push down on mafic rocks until they become so deeply buried that they melt under the high subterranean pressures and temperatures, transforming into felsic rocks.

Read more on Scientific American

Given that light-colored felsic rocks were abundant billions of years ago, plate tectonics had likely already kicked into action.

Read more on Scientific American