Quartzolite Explained

Quartzolite or silexite is an intrusive igneous rock, in which the mineral quartz is more than 90% of the rock's felsic mineral content, with feldspar at up to 10%.[1] [2] Typically, quartz forms more than 60% of the rock,[3] the rest being mostly feldspar although minor amounts of mica or amphibole may also be present.[2] Quartzolite occurs as dykes, sills, veins, bosses and segregation masses;[3] [4] it is also found in association with greisen and pegmatite.[5] [6] [7] Quartzolite is an extremely rare type of rock.[8] No extrusive rock equivalent of quartzolite is known.[9]

Synonyms

The use of the synonym "silexite" is discouraged because it is the French word for chert, which is a sedimentary rock.[10] Other less common synonyms are "igneous quartz" and "peracidite".[11]

Examples

Formation

Some occurrences of quartzolite are unlikely to have an entirely igneous origin;[8] for example, two types of quartzolite that are associated with deposits of topaz in and around the Mole Granite pluton in Torrington, NSW, are believed to have formed in different ways. One type forms dykes and sills in the granite and in the surrounding metamorphic rocks. The other type has remnants of an earlier granite texture and is found on the outer edges of part of the pluton.[18]

Notes and References

  1. Book: Igneous Rocks:A Classification and Glossary of Terms . Cambridge University Press . Le Maitre, R. W. (editor) . 2002 . Cambridge . 978-0-521-66215-4. 2nd .
  2. Web site: Quartzolite . . BGS Rock Classification Scheme . 20 November 2016.
  3. Web site: Definition of silexite . mindat.org . 20 November 2016.
  4. The Torrington silexite deposits . Lishmund, S.R. . Geological Survey of New South Wales: Quarterly Notes . 1974 . 17 . 3–6.
  5. Web site: Ackley Mo-Sn-F-W . Matty Mitchell Prospectors Resource Room . Newfoundland & Labrador: Explore The Opportunities . 2013 . 21 November 2016 . Fraser, Dean.
  6. Topazový Kvarcolit (Greisen) u Chrastavy v Severních Čechách Jako Metalogenetický Indikátor W-Sn Mineralizace . Zprávy o geologických výzkumech v roce . Topaz quartzolite (greisen) near Chrastava in Northern Bohemia – metallogenic indicator of the W-Sn mineralization . Josef . Klominsky . Ferry . Fediuk . Frantisek . Veselovsky . Pavel . Schovanek . Tomas . Jarchovsky . Zdenìk . Taborsky . cs . 2003 . 112–114 . 0514-8057.
  7. Britholite Group Minerals from REE-Rich Lithologies of Keivy Alkali Granite—Nepheline Syenite Complex, Kola Peninsula, NW Russia . D. . Zozulya . L. . Lyalina . R. . Macdonald . B. . Bagiński . Y. . Savchenko . P. . Jokubauskas . Minerals . 2019 . 9 . 12 . 732 . 10.3390/min9120732. 2019Mine....9..732Z . free .
  8. Web site: BGS Rock Classification Scheme, Volume 1: Classification of igneous rocks . British Geological Survey . 1999 . 19 November 2016 . Gillespie . M.R. . Styles . M.T. . 10.
  9. Book: Handbook of Rocks, Minerals, and Gemstones . Houghton-Mifflin Company . Schumann, Walter . 1993 . Boston . 198 . 978-0-395-51138-1.
  10. Book: Glossary of Geology . American Geological Institute . Neuendorf . K.K.E. . Mehl, Jr. . J.P. . Jackson . J.A. (editors) . 2005 . Alexandria, Virginia . 530 . 978-3642066214. 5th .
  11. Book: Dictionary of Gems and Gemology . Springer . Manutchehr-Danai, M. . 2009 . Berlin . 778. 10.1007/978-3-540-72816-0_19824 . 978-3-540-72795-8 . Silexite . 3rd .
  12. Norman J. . Jackson . Colin J. . Douch . Jabal Hamra REE-mineralized silexite, Hijaz region, Kingdom of Saudi Arabia . Journal of African Earth Sciences . 1986 . 4 . 269–274 . 10.1016/S0899-5362(86)80088-4. 1986JAfES...4..269J .
  13. Pegmatite, Silexite, and Aplite of Northern New York . Miller, William J. . The Journal of Geology . 1919 . 27 . 1 . 28–54 . 10.1086/622638. 1919JG.....27...28M . free .
  14. Chronology and origin of Au-Cu deposits related to paleozoic intracontinental rifting in West Tianshan Mountains, NW China . Li . Huaqin . Chen . Fuwen . Science in China Series B: Chemistry . 2002 . 45 . 108–120 . 10.1007/BF02932212.
  15. Petrology and Petrogenesis of Intrusive in North-East Saveh, Iran . A . R. . Shokouhian Rad . Hadi . Kazemi Koohbanani . S. . Kazemi Koohbanani . N. . Kazemi Koohbanani . International Journal on Technical and Physical Problems of Engineering . 2014 . 6 . 6–11 . 2077-3528.
  16. The Geology of South Georgia: VI. Larsen Harbour Formation . Mair . B.F. . British Antarctic Survey Scientific Reports . 1987 . 111 . 1–60.
  17. Web site: Topaz . NSW Department of Primary Industries . Industrial Mineral Opportunities . 23 November 2016.
  18. Web site: The Torrington Project . Top Tung . 2015 . 23 November 2016 . Skinner, Mike . 24 November 2016 . https://web.archive.org/web/20161124024726/http://www.toptung.com.au/Portals/Toptung/Torrington%20AUSIMM%20Presentation%20Mod.pdf . dead .

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