| 词条 | Alkali feldspar granite |
| 释义 |
|name=Alkali feldspar granite |alternative_name= |type=Igneous |image=File:Rocks - Alkali feldspar granite.JPG |image_size=320 |alt= |caption=Alkali feldspar granite. Holocrystalline texture, coarse-grained. Great amounts of potassium feldspar (orthoclase, pink-reddish in colour) |coordinates= |composition=Potassium feldspar, quartz |composition_secondary=Plagioclase; dark minerals }}Alkali feldspar granite, some varieties of which are called 'red granite',[1] is a felsic igneous rock and a type of granite rich in the mineral potassium feldspar (K-spar). It is a dense rock with a phaneritic texture. The abundance of K-spar gives the rock a predominant pink to reddish hue; peppered with minor amounts of black minerals.[2][3] Chemical compositionAs shown in the QAPF diagram, alkali feldspar granite contains between 20% - 60% quartz. Less quartz content would lead to "quartz alkali feldspar syenite". More than 90% of the total feldspar content is in the form of alkali feldspar. Less than that amount would designate the rock as a granite.[4] Other incorporated silicate minerals may include, very minor amounts of plagioclase feldspar, mica in the form of muscovite and/or biotite, and amphibole (often hornblende). Oxide minerals such as magnetite, ilmenite, or ulvospinel. Some sulfides and phosphates (mainly apatite) may also be present. OccurrenceAlkali feldspar granites generally occur with other alkali-rich granitoids, such as monzogranite and syenogranite, forming part of the A-type granites. They are found in a wide range of tectonic settings and their origins remain uncertain.[5] UsesGranitic rocks in general are of interest to geologists, geochemists, etc., because they provide 'crystallized' telltale clues of their environment of formation.[6] Alkali feldspar granite is used as construction material in the form of dimension stones, and polished slabs or tiles for building facades, pavements, and kitchen countertops.[3] References1. ^{{cite web|title=The Chief Commercial Granites of MA, NH and RI (see, for example, pp. 179-180)|url=http://pubs.usgs.gov/bul/0354/report.pdf|publisher=US Geological Survey}} 2. ^{{cite web|title=FAQ - What is Granite?|url=http://www.usgs.gov/faq/categories/9783/2758%20|publisher=US Geological Survey}} 3. ^1 {{cite web|title=Granite: Characteristics, Uses and Problems|url=http://www.gsa.gov/portal/content/111938|publisher=US General Services Administration}} 4. ^{{cite web|title=Field Classification and Description of Soils and Rock|url=http://yosemite.epa.gov/r9/sfund/r9sfdocw.nsf/3dc283e6c5d6056f88257426007417a2/120f26eb0d420d8b882575e1006899ae/$FILE/SOP-12r0%20Soil%20and%20Rock%20Descriptions.pdf|publisher=US Environmental Protection Agency}} 5. ^{{cite journal|url=http://www.gsinet.ir/photos/pics/granite-latine-article-19.pdf |title=A-type granites and related rocks: Evolution of a concept, problems and prospects |author=Bonin B. |journal=Lithos |year=2007 |volume=97 |issue=1-2 |pages=1–29 |doi=10.1016/j.lithos.2006.12.007 |deadurl=yes |archiveurl=https://web.archive.org/web/20140211080357/http://www.gsinet.ir/photos/pics/granite-latine-article-19.pdf |archivedate=2014-02-11 }} 6. ^{{cite web|title=Granite and Granodiorite|url=http://www.nps.gov/goga/learn/education/granite-and-granodiorite-faq.htm|publisher=US National Park Service}} 1 : Granite |
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