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...

fragmental rocks and massive flows, as well as felsic tuffs, tholeiitic pillow basalts and minor porphyritic felsic flows. Siltstone, greywacke, iron formation...

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...

material had formed. The series is divided into two branches, the continuous (felsic minerals: feldspars) and the discontinuous (mafic minerals). The minerals...

into four chemical types based on silica content: felsic, intermediate, mafic, and ultramafic. Felsic or silicic magmas have a silica content greater than...

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...

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...

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...

The Acasta Gneiss Complex, also called the Acasta Gneiss, is a body of felsic to ultramafic Archean basement rocks, gneisses, that form the northwestern...

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...

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...

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...

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...

magma deep in Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such as granite, quartz monzonite, or diorite...

ISBN 978-85-85047-04-7. and Moulton, B. J. A.; et al. (2008). Volcanology of the Felsic Volcanic Rocks of the Kidd-Munro assemblage in Prosser and Muro Townships...

Maffic tuff Andesite Felsic tuff Maffic tuff Felsic tuff and rhyolite Felsic tuff and mudflow breccias Ore zone Felsic tuff Dacite Felsic tuff Laminated siltstone...

especially of the felsic type such as felsites and rhyolites, may have a cryptocrystalline groundmass as distinguished from pure obsidian (felsic) or tachylyte...

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...

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...

particularly powerful explosive eruptions, and rarer felsic lava shields formed by unusually fluid felsic magmas. Examples of pyroclastic shields include Billy...

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...

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...

simultaneously, with two definite episodes of magma activity, mafic and felsic, the former of which being chiefly composed of gabbro-heavy magma and the...

spun from melted basalt Bimodal volcanism – Eruption of both mafic and felsic lavas from a single volcanic centre Plutonism – Geological theory that Earth's...

orthoclase. Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite. Typically...

trondhjemitic suite of silicified felsic intrusive and flow banded rocks, and sedimentary chert beds. Veins of felsic, chert and ultramafic material intrude...

indicating a different, possibly a more felsic, mineral assemblage. The mechanism to generate a large amount of felsic crust usually requires the presence...

oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks. Geologists generally agree that the following tectonic plates...