Coesite

Source: Wikipedia, the free encyclopedia.
Coesite
2V angle
60–70
References[2]

Coesite (

Norton Company, in 1953.[4][5]

Occurrences

In 1960, a natural occurrence of coesite was reported by

atomic bomb explosion. It was not expected that coesite would survive in high pressure metamorphic rocks
.

In metamorphic rocks, coesite was initially described in

ultrahigh-pressure metamorphism).[8] Such UHP metamorphic rocks record subduction or continental collisions in which crustal rocks are carried to depths of 70 km (43 mi) or more. Coesite is formed at pressures above about 2.5 GPa (25 kbar) and temperature above about 700 °C. This corresponds to a depth of about 70 km in the Earth. It can be preserved as mineral inclusions in other phases because as it partially reverts to quartz
, the quartz rim exerts pressure on the core of the grain, preserving the metastable grain as tectonic forces uplift and expose these rock at the surface. As a result, the grains have a characteristic texture of a polycrystalline quartz rim (see infobox figure).

Coesite has been identified in UHP metamorphic rocks around the world, including the western

Himalayas of Eastern Pakistan,[15] and in the Appalachian Mountains of Vermont.[16][17]

Crystal structure

Atomic structure of coesite

Coesite is a

metastable within the stability field of quartz: coesite will eventually decay back into quartz with a consequent volume increase, although the metamorphic reaction is very slow at the low temperatures of the Earth's surface. The crystal symmetry is monoclinic C2/c, No.15, Pearson symbol mS48.[18]

See also

References

  1. S2CID 235729616
    .
  2. ISBN 0962209716
    . Retrieved December 5, 2011.
  3. ^ "coesite". Dictionary.com Unabridged (Online). n.d.
  4. PMID 17835139
    . The word coesite is pronounced as "Coze-ite", after chemist Loring Coes, Jr.
  5. ISBN 978-0-521-65474-6
    . Retrieved 2012-06-06.
  6. S2CID 45197811
    .
  7. doi:10.1016/0012-821X(77)90012-7
    .
  8. ^
    S2CID 128818052
    .
  9. doi:10.1127/0935-1221/2001/0013-0565
    .
  10. doi:10.1127/0935-1221/2002/0014-0355
    .
  11. ^ Korsakov, A.V.; Shatskiy, V. S. & Sobolev N.V. (1998). "Первая находка коэсита в эклогитах Кокчетавского массива (First occurrence of coesite in eclogites from the Kokchetav Massif)". Doklady Earth Sciences. 359: 77–81.
  12. S2CID 4330257
    .
  13. doi:10.1127/ejm/6/6/0995
    .
  14. ISSN 0091-7613
    .
  15. doi:10.1130/0091-7613(2001)029<0435:CIHEAI>2.0.CO;2
    .
  16. Bibcode:2019AGUFM.V51B..03G
    .
  17. S2CID 224854495
    .
  18. ^ Levien L.; Prewitt C.T. (1981). "High-pressure crystal structure and compressibility of coesite" (PDF). American Mineralogist. 66: 324–333. Archived from the original (PDF) on 2016-06-04. Retrieved 2009-12-15.

External links

Lists
  • Worldwide
  • Africa
  • Antarctica
  • Asia
  • Australia
  • Europe
  • North America
  • South America
  • By country
  • Possible

Confirmed
≥20 km diameterTopicsResearch
Retrieved from "https://en.wikipedia.org/w/index.php?title=Coesite&oldid=1218473238"