Itqiy meteorite

The Itqiy meteorite is an enstatite-rich stony-iron meteorite. It is classified as an enstatite chondrite of the EH group that was nearly melted and is therefore very unusual for that group.[2][4] Other classifications have been proposed and are an ongoing scientific debate.

Itqiy meteorite
TypeChondrite (ongoing scientific debate)
ClassEnstatite chondrite (ongoing scientific debate)
GroupEH7-an (ongoing scientific debate)
Parent bodyNWA2526-Itqiy[1]
CompositionEnstatite (78 %), meteoric iron (22 %), sulfides.[2]
CountryWestern Sahara[3]
Coordinates26°35′27″N 12°57′8″W[3]
Observed fallYes[3]
Fall date1990[3]
Found date1990 + 2000-07[3]
TKW0.410 kilograms (0.90 lb)[3] + 4.310 kilograms (9.50 lb)[3]

History

Itqiy was initially attributed to a 1990 fireball in Western Sahara. One stone was recovered by a nomad, and a second stone was recovered in July 2000 by Marc, Luc, and Jim Labenne who were searching for meteorites in the same location.[3] The meteorite was analyzed in 2001.[5] Later work showed that the meteorite had fallen nearly 6,000 years ago and was not associated with any recent fireball. [6]

Mineralogy and petrology

Itqiy is a stony meteorite consisting of 78% enstatite and 22% meteoric iron. The meteoric iron is kamacite with 5.77% nickel. Small amounts of other minerals include troilite, Mg-Mn-Fe sulfides and Fe-Cr sulfides.[2][7]

Classification

The meteorite was described as an "ungrouped stony meteorite" in 2000, and reclassified as an "ungrouped enstatite meteorite" in 2001.[2][7] In 2006, Itqiy was classified as a member of the EH enstatite chondrites, with a petrologic type of 7, emphasizing that it was a strongly metamorphosed EH chondrite.[2]

Itqiy represents a rock that formed through partial melting of an EH chondrite. This process removed the more volatile minerals like plagioclase.[8] In 2010-1 it was proposed that Itqiy, QUE 94204, QUE 97289, QUE 97348, NWA 2526 and possibly Yamato 793225 form a new group from the same parent body that should be called "primitive enstatite achondrites".[8] [9]

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See also

References
  1. Keil, Klaus (31 December 2009). "Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies". Chemie der Erde - Geochemistry. 70 (4): 295–317. Bibcode:2010ChEG...70..295K. doi:10.1016/j.chemer.2010.02.002.
  2. "Itqiy". Meteoritical Society.
  3. "Itqiy". Meteoritical Society. Retrieved 21 December 2012.
  4. "EH7-an". Meteoritical Society.
  5. Grossman, Jeffrey N.; Jutta Zipfel (2001). "The Meteoritical Bulletin, No. 85, 2001 September" (PDF). Meteoritics & Planetary Science. 36: A293–A322. Bibcode:2001M&PS...36..293G. doi:10.1111/j.1945-5100.2001.tb01542.x. Retrieved 21 December 2012.
  6. {{cite journal|last=Patzer|first=Andrea|author2=Dolores Hill|author3=William Boynton|author4=Luitgard Franke|author5=Ludolf Schultz|author6=Timothy Jull|author7=Lanny McHargue|author8=Ian Franchi|title=Itqiy: A study of noble gases and oxygen isotopes including its terrestrial age and a comparison with Zakłodzie|journal=Meteoritics & Planetary Science|date=2010|volume=37|pages=823–833|doi=10.1111/j.1945-5100.2002.tb00858.x |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1945-5100.2002.tb00858.x%7Caccessdate=14 July 2020}
  7. Patzer, Andrea; Hill, Dolores H.; Boynton, William V. (1 November 2001). "Itqiy: A metal-rich enstatite meteorite with achondritic texture". Meteoritics & Planetary Science. 36 (11): 1495–1505. Bibcode:2001M&PS...36.1495P. doi:10.1111/j.1945-5100.2001.tb01841.x.
  8. Keil, Klaus (2010). "Enstatite achondrite meteorites (aubrites) and the histories of their asteroidal parent bodies". Chemie der Erde - Geochemistry. 70 (4): 295–317. Bibcode:2010ChEG...70..295K. doi:10.1016/j.chemer.2010.02.002.
  9. IZAWA, Matthew R. M.; FLEMMING, Roberta L.; BANERJEE, Neil R.; MATVEEV, Sergei (1 November 2011). "QUE 94204: A primitive enstatite achondrite produced by the partial melting of an E chondrite-like protolith". Meteoritics & Planetary Science. 46 (11): 1742–1753. Bibcode:2011M&PS...46.1742I. doi:10.1111/j.1945-5100.2011.01263.x.
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