On Offer: 21.53 gram slice of Al Bir Lahlou 001 Achondrite-ung

Dimensions: 70mm x 60mm x 1.5mm

Official Name: Al Bir Lahlou 001

Abbreviation: ABL 001

Year found: 2021

Country: Western Sahara

Description: 21.53 gram slice of an amazing ungrouped achondritic meteorite with official name Al Bir Lahlou 001.

Classification: Achondrite Ungrouped (norite) - one of the newer members of a small but growing number of differentiated meteorites, igneous achondrites that don’t fit into any existing classifications from a large unknown differentiated parent body. Composed of ~60% An98 plagioclase (norite)."

Stable oxygen isotopes plot near the HED array and pyroxenes are diogenitic. However, overall modal composition is unlike the diogenites being composed of ~60% plagioclase. Furthermore the plagioclase is more Ca-rich and closer to lunar and angrite plagioclase at An98.

This is an interesting and unique representative of an important batch of ancient but fully differentiated ungrouped achondrites emerging from the Northwest African deserts recently. These types of achondrites are helping us understand the dynamics of early accretion and solar system formation and at times forcing us to adjust well establish chronologies and models.

The ungrouped classification is given because it doesn't fall into any existing taxonomical meteorite group. So, while it is indeed a "classified" meteorite, we know it is a differentiated achondrite, we know it's oxygen isotope ratio plots closely to the trachyteitic ureilite, we know it shares some characteristics with diogenites, and we know it's a "norite". We also know that none of the existing names we have to choose from to pin on this meteorite really fit. We really like to name things though, and so we just throw a generic "ungrouped" achondrite tag on it, and call it a day.

These particular specimen show a beautiful intermingling of cream-colored plagioclase grains and vivid-green pyroxene grains. This slice is polished on one side.

What you get: 21.53 gram

Al Bir Lahlou 001 slice as shown, and signed Certificate of Authenticity.

We offer a 100% no questions asked 30 day return policy.

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Al Bir Lahlou 001

Basic information

Name: Al Bir Lahlou 001
This is an OFFICIAL meteorite name.
Abbreviation: ABL 001
Observed fall: No
Year found: 2021
Country: Western Sahara
Mass: 12.4 kg

Classification
history:

Recommended:

Achondrite-ung [explanation]

This is 1 of 131 approved meteorites classified as Achondrite-ung. [show all]
Search for other: Achondrites, Ungrouped achondrites

Comments:

Approved 15 Dec 2021

Writeup

Writeup from MB 110:

Al Bir Lahlou 001 (ABL 001) 26.03884, -9.27921

Western Sahara

Purchased: 2021

Classification: Ungrouped achondrite

History: The stone was found by meteorite hunters in Western Sahara.

Physical characteristics: Smooth sand blasted exterior and saw-cut, exposed interior show a cumulate intermingling of cream-colored plagioclase grains and vivid-green pyroxene grains.

Petrography: (C. Agee and A. Ross, UNM) This meteorite contains approximately 60% plagioclase, 35% low-Ca pyroxene, minor phases include olivine, low-Ni iron metal, and Cr-spinel. Grain boundaries between plagioclase and pyroxene are gradational and occupied by blebby intergrowths of both phases. Olivine was observed as small (~100 μm) inclusions in pyroxene. Metal is nearly pure iron with trace amounts of cobalt -- nickel was barely detectable with the microprobe.

Geochemistry: (A. Ross, UNM) Olivine Fa_36.0±3.9, Fe/Mn=35±2, n=6; low-Ca pyroxene Fs_28.6±2.7Wo_3.6±0.9, Fe/Mn=22±1, Cr₂O₃=0.77±.14 (wt%), n=6; plagioclase An_97.9±0.1Ab_2.0±0.1Or_0.1±0.0, n=4; iron metal Co=0.24±0.10 (wt%), n=5. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ¹⁸O= 3.821, 3.829, 3.939; δ¹⁷O= 1.723, 1.731, 1.792; Δ¹⁷O= -0.295, -0.291, -0.288 (linearized, per mil, TFL slope=0.528).

Classification: Ungrouped achondrite. This meteorite is a norite. It has oxygen isotopes values that are about 0.05 per mil below the HED array. The pyroxene compositions are similar to that found in diogenites, however the plagioclase abundance (60%) of this norite is much higher than in any diogenite (orthopyroxenite). The anorthite (An₉₈) content of the plagioclase is significantly higher than typical HED values.

Specimens: 22 g including a probe mount on deposit at UNM, Said Bachir holds the main mass.

Data from:
MB110
Table 0
Line 0:

Place of purchase:	Western Sahara
Date:	P 2021
Latitude:	26.03884
Longitude:	-9.27921
Mass (g):	12400
Pieces:	1
Class:	Achondrite-ung
Shock stage:	low
Weathering grade:	moderate
Fayalite (mol%):	36.0±3.9
Ferrosilite (mol%):	28.6±2.7
Wollastonite (mol%):	3.6±0.9
Classifier:	C. Agee, UNM
Type spec mass (g):	22
Type spec location:	UNM
Main mass:	Said Bachir
Comments:	Field name SBM-1; submitted by C. Agee

Plots:

O isotopes:

Institutions
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)

Catalogs:

References:

Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4

Find references in NASA ADS:
Find references in Google Scholar:

Geography:

Western Sahara

Coordinates:
Recommended::	(26° 2' 20"N, 9° 16' 45"W)

Statistics:
This is 1 of 265 approved meteorites from Western Sahara (plus 20 unapproved names)