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Hassi el Madani 002
Basic information Name: Hassi el Madani 002
     This is an OFFICIAL meteorite name.
Abbreviation: HeM 002
Observed fall: No
Year found: 2022
Country: Algeria
Mass:help 465 g
Recommended:  Achondrite-ung    [explanation]

This is 1 of 157 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 14 Jan 2024
Writeup from MB 113:

Hassi el Madani 002 (HeM 002)        28.509197, -2.262236

Adrar, Algeria

Purchased: 2022

Classification: Ungrouped achondrite

History: Purchased by Habib-naji Naji on August 4, 2022 in Tindouf, Algeria, subsequently purchased by Jay Piatek in 2023. Reportedly found 2 km south-southwest of the hamlet of Hassi M’dakane and approximately 130 km southwest of highway N6 in Algeria.

Physical characteristics: Single stone with two visually distinct lithologies and apparent sharp boundaries which are designated 1) "dark" lithology (host), and 2) "light" lithology (clasts). The light clasts makes up approximately 15% of the total surface area and is light green in color with patches of smooth black fusion crust. A fresh chipped surface of the light lithology reveals a granular texture with light-yellow color lacking significant metallic/sulfide grains. The dark host lithology makes up ~85% of the surface area and is dark brown in color with some patches of remnant fusion crust but a mostly smooth sandblasted appearance. A sawcut of the dark lithology shows a medium to fine matrix texture of gray grains with scattered reflective sulfides.

Petrography: (C. Agee, M. Spilde, A. Ross, UNM) Microprobe examination and reflected light microscopy were performed on three polished mounts. 1) Dark host lithology: one polished mount of the dark lithology was analyzed showing a mineralogy consistent with a harzburgite (i.e.: ultramafic achondrite with no chondrules observed) with approximately 50% olivine, 35% orthopyroxene, with minor pyrrhotite, plagioclase (oligoclase), merrillite, Cl-rich apatite, chromite, kamacite and taenite. Numerous very fine Fe-oxide veinlets are ubiquitous in the dark lithology. 2) Light lithology clast: two polished mounts of the light lithology were analyzed showing a mineralogy consistent with a plagioclase bearing dunite with approximately 85-90% olivine, 5-10% oligoclase (maskelynite), 2-5% augite, with minor chromite and Cl-rich apatite, and with trace amounts of ilmenite, kamacite and taenite. Mean olivine grain size is approximately 200 μm with a range of approximately 50-500 μm. Maskelynite is primarily interstitial between olivine grains.

Geochemistry: (M. Spilde, A. Ross, C. Agee, UNM) Light lithology: olivine Fa25.2±0.3, Fe/Mn=49±2, n=13; maskelynite Ab74.9±5.1An19.2±4.0Or5.9±1.5, n=10; augite Fs7.9±0.5Wo45.2±0.7, Fe/Mn=22±3, n=12; chromite Cr2O3=51.6±1.6 (wt%), n=4; apatite Cl=4.3±0.8, F=0.32±0.11 (wt%) n=11. Dark lithology: olivine Fa25.4±0.5, Fe/Mn=51±2, n=10; low-Ca pyroxene Fs22.0±01.4Wo1.6±0.2, Fe/Mn=31±3, n=9; plagioclase Ab83.2±1.0An10.2±0.5Or6.6±0.6, n=12; chromite Cr2O3=54.9±0.3 (wt%), n=6; apatite Cl=4.5±0.5, F=0.23±0.11 (wt%) n=9; pyrrhotite Fe=44.4±3.0, S=55.2±2.8 (atom%). Oxygen isotopes (K. Ziegler, UNM) Light clast: 5 acid-washed fragments analyzed by laser fluorination gave δ18O=4.519, 4.622, 4.416, 4.311, 4.267; δ17O=2.714, 2.784, 2.658, 2.639, 2.607; Δ17O=0.328, 0.344, 0.327, 0.363, 0.354 (linearized, all per mil, TFL slope=0.528); Host lithology (dark): 2 acid-washed fragments analyzed by laser fluorination gave δ18O=5.298, 5.438; δ17O= 3.807, 3.867; Δ17O=1.010, 0.996 (linearized, all per mil, TFL slope=0.528)

Classification: This meteorite is an achondritic breccia with two distinctly different lithologies with significantly different oxygen isotope values. The host lithology has oxygen isotopes that plot within the LL chondrite field. The light clast has oxygen isotopes that plot within the martian meteorite (SNC) array whereas The mineralogy, geochemistry, and oxygen isotopes of the light clasts resemble martian chassignites. The mineralogy, geochemistry, and oxygen isotopes of the dark host lithology are consistent with an ungrouped achondrite having LL-affinities.

Specimens: 21 g on deposit at UNM, Jay Piatek holds the main mass.

Data from:
  Table 0
  Line 0:
Place of purchase:Algeria
Date:P 2022
Mass (g):465.2
Shock stage:high
Weathering grade:low
Fayalite (mol%):25.2±0.3, 25.4±0.5
Ferrosilite (mol%):7.9±0.5, 22.0±01.4
Wollastonite (mol%):45.2±0.7, 1.6±0.2
Classifier:C. Agee, UNM
Type spec mass (g):21
Type spec location:UNM
Main mass:Jay Piatek
Comments:Fieldname HN-2042; submitted by C. Agee
Plots: O isotopes:  
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
References: Published in Meteoritical Bulletin, no. 113, in preparation (2024)
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     Recommended::   (28° 30' 33"N, 2° 15' 44"W)

     This is 1 of 204 approved meteorites from Adrar, Algeria (plus 1 unapproved name)
     This is 1 of 1376 approved meteorites from Algeria (plus 31 unapproved names) (plus 4 impact craters)
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