Search results
Results from the WOW.Com Content Network
Quartz diorite from Dúbrava, Nízke Tatry Mountains, Slovakia. Quartz diorite is an igneous, plutonic rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz is present at between 5 and 20% of the rock.
Diorite itself is more narrowly defined, as a dioritoid in which quartz makes up less than 5% of the QAPF content, feldspathoids are not present, and plagioclase makes up more than 90% of the feldspar content. [11] [5] [6] Diorite may contain small amounts of quartz, microcline, and olivine.
Quartz diorite – Igneous, plutonic rock – A diorite with >5% modal quartz; Quartz monzonite – Type of igneous rock – An intermediate plutonic rock, essentially a monzonite with 5–10% modal quartz; Quartzolite – Extremely rare igneous rock made mostly of quartz – An intrusive rock composed mostly of quartz
Because of its coloring, it is often confused with granite, but whereas granite contains more than 20% quartz, quartz monzonite is only 5–20% quartz. Rock with less than five percent quartz is classified as monzonite. A rock with more alkali feldspar is a syenite whereas one with more plagioclase is a quartz diorite. [1]
Quartz (SiO 2) is present as more than 20% of the total quartz-alkali feldspar-plagioclase-feldspathoid content of the rock. [1] [2] Amphiboles and biotite are common in lesser quantities, while accessory minerals include apatite, magnetite and zircon. [3] [4] In older references tonalite is sometimes used as a synonym for quartz diorite.
It contains a large amount of sodium (Na) and calcium (Ca) rich plagioclase, potassium feldspar, quartz, and minor amounts of muscovite mica as the lighter colored mineral components. Biotite and amphiboles often in the form of hornblende are more abundant in granodiorite than in granite, giving it a more distinct two-toned or overall darker ...
The relative proportions of feldspars and quartz in dacite, and in many other volcanic rocks, are illustrated in the QAPF diagram. This defines dacite as having a content of 20% to 60% quartz, with plagioclase making up 65% or more of its feldspar content.
Tight folds at the contact between Icart Gneiss (light) and mylonitised quartz diorite (dark), western end of Lihou Island. Many of the rocks present in the south of Guernsey may also be observed on Lihou Island. At the western coast of the island, a shear zone is exposed at the contact between the Perelle Foliated Quartz Diorite and the Icart ...