In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.[1] It is contrasted with mafic rocks, which are relatively richer in magnesium and iron. Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Felsic magma or lava is higher in viscosity than mafic magma/lava, and have low temperatures to keep the felsic minerals molten.
Felsic rocks are usually light in color and have specific gravities less than 3. The most common felsic rock is granite. Common felsic minerals include quartz, muscovite, orthoclase, and the sodium-rich plagioclase feldspars (albite-rich).
^Marshak, Stephen, 2009, Essentials of Geology, W. W. Norton & Company, 3rd ed. ISBN 978-0393196566
In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic...
into four chemical types based on silica content: felsic, intermediate, mafic, and ultramafic. Felsic or silicic lavas have a silica content greater than...
unconsolidated sediments. The typical location for VMS deposits is at the top of the felsic volcanic sequence, within a sequence of volcaniclastic tuffaceous epiclastics...
into four chemical types based on silica content: felsic, intermediate, mafic, and ultramafic. Felsic or silicic magmas have a silica content greater than...
viscosity similar to thick, cold molasses or even rubber when erupted. Felsic magma, such as rhyolite, is usually erupted at low temperature and is up...
pegmatite masses occur with granite. Granite forms from silica-rich (felsic) magmas. Felsic magmas are thought to form by addition of heat or water vapor to...
Archean felsic volcanic rocks are felsic volcanic rocks that were formed in the Archean Eon (4 to 2.5 billion years ago). The term "felsic" means that...
fragmental rocks and massive flows, as well as felsic tuffs, tholeiitic pillow basalts and minor porphyritic felsic flows. Siltstone, greywacke, iron formation...
spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica (as in rhyolite, dacite, or...
The Acasta Gneiss Complex, also called the Acasta Gneiss, is a body of felsic to ultramafic Archean basement rocks, gneisses, that form the northwestern...
contains a high percentage (>63%) of silica, the lava is described as felsic. Felsic lavas (dacites or rhyolites) are highly viscous and are erupted as domes...
Eruptions of rhyolite lava are relatively rare compared to eruptions of less felsic lavas. Only four eruptions of rhyolite have been recorded since the start...
minimal crystal growth. It is an igneous rock. Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium...
sial is 2.7 gm/cc. Geologists often refer to the rocks in this layer as felsic, because they contain high levels of feldspar, an aluminium silicate mineral...
especially of the felsic type such as felsites and rhyolites, may have a cryptocrystalline groundmass as distinguished from pure obsidian (felsic) or tachylyte...
felsic rocks. The term roughly corresponds to the older basic rock class. Mafic lava, before cooling, has a low viscosity, in comparison with felsic lava...
been mafic in composition. The first continental crust, which was more felsic in composition, formed by the partial melting of this mafic crust. The presence...
the last six to seven million years and is primarily mafic rock with some felsic rock. Geologists debate the exact origins of the island and some have proposed...
particularly powerful explosive eruptions, and rarer felsic lava shields formed by unusually fluid felsic magmas. Examples of pyroclastic shields include Billy...
oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks. Geologists generally agree that the following tectonic plates...
spun from melted basalt Bimodal volcanism – Eruption of both mafic and felsic lavas from a single volcanic centre Plutonism – Geological theory that Earth's...
supracrustal rocks in Eastern Ontario, as well as some of the most ancient felsic magmatic events in this section of the Superior craton. Uranium-lead dating...
siliceous igneous rocks containing greater than 66% of silica, known as felsic rocks, quartz is not abundant in igneous rocks. In basic rocks (containing...
feldspar. The alternate spelling, felspar, has fallen out of use. The term 'felsic', meaning light coloured minerals such as quartz and feldspars, is an acronymic...
a volcanic island in the Sea of Japan, the composition of which is more felsic than Jeju. The volcanic islands tend to be younger, the more westward. Because...
indicating a different, possibly a more felsic, mineral assemblage. The mechanism to generate a large amount of felsic crust usually requires the presence...
(plural lithophysae, from Greek lithos "stone" + physan "to blow") is a felsic volcanic rock with a spherulitic structure and interior cavity with concentric...
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