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Northwest Africa 13580
Basic information Name: Northwest Africa 13580
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13580
Observed fall: No
Year found: 2020
Country: Algeria
Mass:help 700 g
Classification
  history:
Recommended:  Diogenite    [explanation]

This is 1 of 449 approved meteorites classified as Diogenite.   [show all]
Search for other: Achondrites, Diogenites, and HED achondrites
Comments: Approved 17 Dec 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13580 (NWA 13580)

Algeria

Purchased: 2020

Classification: HED achondrite (Diogenite)

History: A single 700 g sample was found near Tindouf, Algeria, in 2019. Didi Baidari purchased the sample from a meteorite dealer in Tindouf.

Physical characteristics: The exterior of the ellipsoidal sample is wind-ablated and is an orangish-cream-colored and has brownish grains protruding through the surface. The interior shows a crystalline brecciated texture composed of cream colored and dark green crystals.

Petrography: Description and Classification (A. Love, App) Sample is a breccia composed of cumulate-textured clasts composed of (vol%): 2-5 mm grains of low-Ca pyroxene (66) and plagioclase (34) set within a recrystallized host of finer-grained (avg. grain-size 55µm) plagioclase and low-Ca pyroxene. Some pyroxenes show lamellar and blebby exsolution. Mineral phases within the recrystallized portion share 120º grain boundaries between adjacent minerals. Additional minerals are high-Ca pyroxene, chromite and troilite.

Geochemistry: Low-Ca Pyroxene (Fs31.5±0.7Wo3.7±0.4, Fe/Mn=27.4±0.9, Mg#=67.2±0.7, n=16); high-Ca pyroxene (Fs16.0±0.1Wo39.5±0.6, Fe/Mn=21.6±1.3, Mg#73.5±0.2, n=3); plagioclase (An96.8±0.2Or0.0, n=10); chromite (Cr#=75.7±3.7, TiO2=1.5±0.1wt%, Mg#21.7±1.24, n=9).

Classification: Achondrite (diogenite, noritic). Based on mineralogy, texture and Fe/Mn ratios within pyroxenes, sample is an HED achondrite. Composition of plagioclase, Fe/Mn ratios and Mg# of pyroxenes are intermediate between diogenites and cumulate eucrites. Ti Vs. Al of low Ca-pyroxenes plot within the field of diogenites. Ti, Al, Cr-content and Mg# of chromite fall in the range observed for diogenites. Abundance of plagioclase (34 vol%) within sample is anomalous for diogenites.

Specimens: Didi Baidari holds the main mass. 10 fragments weighing 23.89 g and a polished thin section and mount are on deposit at App.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Tindouf
Date:P 2020
Mass (g):700
Pieces:1
Class:Diogenite
Shock stage:low
Weathering grade:low
Ferrosilite (mol%):31.5±0.7; 16.0±0.1
Wollastonite (mol%):3.7±0.4; 39.5±0.6
Magnetic suscept.:2.76
Classifier:Anthony Love
Type spec mass (g):23.89
Type spec location:App
Main mass:Didi Baidari
Comments:Submitted by Anthony Love
Institutions
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Anthony Love   
Geography:

Algeria
Coordinates:Unknown.

Statistics:
     This is 1 of 1073 approved meteorites from Algeria (plus 26 unapproved names) (plus 4 impact craters)

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