Tonalite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less alkali feldspar. Quartz is present as more than 20% of the rock. Amphiboles and pyroxenes are common accessory minerals. Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when rock (magma) cools and solidifies, with or without crystallisation, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Pluton redirects here. ... Pluton redirects here. ... The rocky side of a mountain creek near Orosí, Costa Rica. ... 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. ... Granite is typical phaneritic igneous rock. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Oligoclase is a rock-forming mineral belonging to the plagioclase feldspars. ... Andesine is a feldspar mineral, a part of the plagioclase series. ... Quartz is one of the most common minerals in the Earths continental crust. ... For the logical fallacy, see Amphibology. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ...

In older references tonalite is sometimes used as a synonym for quartz diorite, however the current IUGS classification defines tonalite as having greater than 20% quartz and quartz diorite with from 5 to 20% quartz. Quartz diorite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. ... The International Union of Geological Sciences (IUGS) was founded in 1961 and is a Scientific Union member of the International Council for Science (ICSU), which it recognizes as the coordinating body for the international organization of science. ... A QAPF diagram is a double triangle diagram which is used to classify igneous rocks based on mineralogic composition. ...

Trondhjemite is an orthoclase deficient variety of tonalite with minor biotite as the only mafic mineral, named after Norway's third largest city, Trondheim. Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. ... Orthoclase (KAlSi3O8) is an important tectosilicate mineral, which forms igneous rock. ... A Biotite slice Biotite is a common phyllosilicate mineral that contains potassium, magnesium, iron and aluminium. ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ... County Sør-Trøndelag District Municipality NO-1601 Administrative centre Trondheim Mayor (2005) Rita Ottervik (AP) Official language form Neutral Area  - Total  - Land  - Percentage Ranked 258 342 km² 322 km² 0. ...