felsic
adjective
- describes rocks with high silica content
Wiktionary
adj
Etymology: Blend of feldspar + silica, + -ic.
- Enriched in minerals predominantly composed of the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.
“Much of the southern half of the southeastern body is a mafic syenite, slightly more felsic than the shonkinite.”
“Within comagmatic suites, successively younger granitoids are commonly, but not invariably, more felsic, representing progressively lower temperature mineral assemblages.”
noun
Etymology: Blend of feldspar + silica, + -ic.
- A rock with such properties.
“The central part of this nepheline syenite is very white felsics with black mafics in it. The entire area contains many nepheline-bearing dike rocks, but almost all are gray or pink or even red due to the color in the felsics.”
“There are also calcalkaline felsics that have highly enriched LREE^([light rare-earth element]) patterns with lower overall abundances.”