Dacite (/ ˈdeɪsaɪt /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.

Dacite is a fine-grained igneous rock that is normally light in color. It is often porphyritic. Dacite is found in lava flows, lava domes, dikes, sills, and pyroclastic debris. It is a rock type usually found on continental crust above subduction zones, where a …

Sep 14, 2023 · Dacite is a fine-grained, light-colored volcanic or extrusive igneous rock. Its composition is felsic and mainly has plagioclase feldspar, quartz, lesser alkali feldspar, minor hornblende, biotite, and other mafic minerals. Plagioclase is more alkali feldspar in this rock. Guido Stache, an Austrian geologist, proposed the term dacite in 1863.

Dacite forms when viscous, felsic lava rapidly cools at or near the Earth’s surface, negating the opportunity for the formation of large crystals in the groundmass. This most commonly occurs in volcanic arcs associated with subduction zones but also occurs in hot spots and other settings.

May 10, 2024 · Considering mineral and chemical composition, dacite is the extrusive equivalent of granodiorite, a plutonic or intrusive igneous rock. How does dacite form? Dacite forms when silicic magma erupts, quickly cools, and solidifies on the Earth’s surface or in shallow sills, dikes, and other intrusions.

Dacite, volcanic rock that may be considered a quartz-bearing variety of andesite. Dacite is primarily associated with andesite and trachyte and forms lava flows, dikes, and sometimes massive intrusions in the centres of old volcanoes.

Dacitic rocks with felsics comprising >20% quartz and alkali feldspar/plagioclase <0.5. A fine-grained extrusive rock with a similar general composition to andesite, but having a more sodic plagioclase and more K-feldspar and quartz; it is the extrusive equivalent of granodiorite. Synonym: quartz andesite.

Dacite, from Dacia, a Roman province, Transylvania, Romania, is a volcanic rock that may be considered a quartz-bearing variety of andesite. Dacite is primarily associated with andesite and trachyte and forms lava flows, dikes, and sometimes massive intrusions in …

Dacite lavas are viscous and tend to form thick blocky lava flows or steep-sided piles of lava called lava domes. Dacitic magmas tend to erupt explosively, thus also ejecting abundant ash and pumice.

Dacite (/ ˈdeɪsaɪt /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.