Ignimbrite is a deposit of a pyroclastic flow.

Vesicular olivine basalt from La Palma (green phenocrysts are olivine).

Volcanic rock is an igneous rock of volcanic origin. Image File history File links Ignimbrite. ... Image File history File links Ignimbrite. ... Ignimbrite is a volcanic pyroclastic rock, often of dacitic or rhyolitic composition. ... Pyroclastic flows sweep down the flanks of Mayon Volcano, Philippines, in 1984 Pyroclastic flows are a common and devastating result of some volcanic eruptions. ... Image File history File links Olivine_basalt2. ... Image File history File links Olivine_basalt2. ... Satellite image of La Palma, with the Caldera de Taburiente visible (north is to the lower right). ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... For other uses, see Volcano (disambiguation). ...

Texture

Volcanic rocks are usually fine-grained or aphanitic to glassy in texture. They often contain clasts of other rocks and phenocrysts. Phenocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye. Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix. An aphanite is an igneous rock with a fine-grained structure. ... A xenolith A xenolith (Greek: foreign rock) is a rock fragment which becomes enveloped in a larger rock during the latters development and hardening. ... The rocky side of a mountain creek near Orosí, Costa Rica. ... Example of phenocrysts in rhomb porphyry from the Oslo rift area in Norway A phenocryst is a relatively large and usually conspicuous crystal formed in the mass of a porphyritic igneous rock. ... Quartz crystal Synthetic bismuth crystal Insulin crystals Gallium, a metal that easily forms large single crystals A huge monocrystal of potassium dihydrogen phosphate grown from solution by Saint-Gobain for the megajoule laser of CEA. In chemistry and mineralogy, a crystal is a solid in which the constituent atoms, molecules... The matrix or groundmass of an igneous rock consists of fine grained often microscopic crystals in which larger crystals (phenocrysts) are embedded. ... A human eye. ... Rhomb porphyry from the Oslo rift area in Norway Rhomb porphyry is a volcanic rock with gray-white large porphyritic rhomb shaped phenocrysts enbedded in a very fine grained red-brown matrix. ... For other uses of the word rhombus, see Rhombus (disambiguation) This shape is a rhombus In geometry, a rhombus (or rhomb; plural rhombi) is a quadrilateral in which all of the sides are of equal length, i. ... A phenocryst is a relatively large and usually conspicuous crystal formed in the mass of a porphyritic igneous rock. ...

Volcanic rocks often have a vesicular texture, which is the result voids left by volatiles escaping from the molten lava. Pumice is a rock, which is an example of explosive volcanic eruption. It is so vesicular that it floats in water. Vesicular texture is a volcanic rock texture characterised by, or containing, many vesicles. ... Look up volatile in Wiktionary, the free dictionary. ... Look up lava, Aa, pahoehoe in Wiktionary, the free dictionary. ... Specimen of highly porous pumice from Teide volcano on Tenerife, Canary Islands. ... An explosive eruption is a volcanic term to describe a violent, explosive type of eruption. ... This article is about volcanoes in geology. ... Impact of a drop of water creating circular capillary waves. ...

Naming

Volcanic rocks are named according to both their chemical composition and texture. Basalt is a very common volcanic rock with low silica content. Rhyolite is a volcanic rock with high silica content. Rhyolite has silica content similar to that of granite granite while basalt is compositionally equal to gabbro. Intermediate volcanic rocks include andesite, dacite, trachyte and latite. The chemical composition of a substance refers to the elements of which the substance is composed. ... Basalt Basalt (IPA: ) is a common gray to black volcanic rock. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Rhyolite This page is about a volcanic rock. ... Quarrying granite for the Mormon Temple, Utah Territory. ... Gabbro specimen. ... A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. ... Gray, red, black, altered white/tan, flow-banded pumice dacite poop Dacite (IPA: ) is a high-silica igneous, volcanic rock. ... A sample of trachyte Trachyte is an igneous, volcanic rock with an aphanitic to porphyritic texture. ... Latite is an igneous, volcanic (extrusive) rock, with aphanitic to porphyritic texture. ...

Pyroclastic rocks are the product of explosive volcanism. They are often felsic (high in silica). Pyroclastic rocks are often the result of volcanic debris, such as ash, bombs and tephra, and other volcanic ejecta. Examples of pyroclastic rocks are tuff and ignimbrite. Pyroclastic rocks or pyroclastics (derived from the Greek πῦρ, meaning fire, and κλαστός, meaning broken) are debris thrown from volcanoes during an eruption. ... Felsic is a term used in geology to refer to silicate minerals, magmas, and rocks which are enriched in the lighter elements such as silica, oxygen, aluminium, sodium, and potassium. ... Tephra refers to air-fall material produced by a volcanic eruption regardless of composition or fragment size. ... This article is about volcanoes in geology. ... In volcanology, ejecta consists of particles that came out of a volcanic vent, traveled though the air or under water, and fell back on the ground surface or on the ocean floor. ... Welded tuff at Golden Gate in Yellowstone National Park Tuff (from the Italian tufo) is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. ... Ignimbrite is a volcanic pyroclastic rock, often of dacitic or rhyolitic composition. ...

Shallow intrusions, which possess structure similar to volcanic rather than plutonic rocks are also considered to be volcanic. Devils Tower, an igneous intrusion exposed when the surrounding softer rock eroded away. ...

See also

• Intrusion

I rock!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Devils Tower, an igneous intrusion exposed when the surrounding softer rock eroded away. ...