Meteoritical Bulletin: Entry for Northwest Africa 11907

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Northwest Africa 11907

Basic information

Name: Northwest Africa 11907
This is an OFFICIAL meteorite name.
Abbreviation: NWA 11907
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass: 1327 g

Classification
history:

Meteoritical Bulletin:	MB 107	(2018)	LL3
Recommended:			LL3 [explanation]

This is 1 of 409 approved meteorites classified as LL3. [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)

Comments:

Approved 24 Jul 2018

Writeup

help

Writeup from MB 107:

Northwest Africa 11907 (NWA 11907)

(Northwest Africa)

Purchased: 2018

Classification: Ordinary chondrite (LL3)

History: Darryl Pitt purchased from Said Haddany at the Tucson Gem and Mineral Show in January 2018

Physical characteristics: Single stone with fusion crust. Saw cut reveals two distinct lithologies, one lighter and one darker in color. Numerous well formed, closely packed chondrules, some up to 2 mm in diameter. Average apparent chondrule diameter is 750±450 μm (n=16). Scattered metal/sulfide grains observed.

Petrography: (C. Agee, UNM) Microprobe examination shows many porphyritic chondrules in both lithologies, most with mesostasis and glass.

Geochemistry: (C. Agee,UNM) All olivine Fa_27.2±10.5, n=42; all low-Ca pyroxene Fs_23.6±8.3Wo_0.9±0.5, n=12. Dark lithology: olivine Fa_22.1±11.4, Cr₂O₃=0.11±0.16, Fe/Mn=51±17, n=21; low-Ca pyroxene Fs_18.2±0.2Wo_1.1±0.8, Fe/Mn=21±1, n=6. Light lithology: olivine Fa_32.4±6.3, Cr₂O₃=0.05±0.08, Fe/Mn=66±13, n=21; low-Ca pyroxene Fs_29.2±3.2Wo_1.1±0.5, Fe/Mn=46±11, n=6.

Classification: Ordinary chondrite (LL3), estimated sub-type LL3.2-3.3 based on mean Fa content of olivine and the 1-sigma Fa content of olivine, and on mean Cr₂O₃ content of ferroan olivine and the 1-sigma Cr₂O₃ content of ferroan olivine (Grossman and Brearley, 2005). Similar to St. Marys County (LL3.3), GRO 95502 (L3.2) and GRO 95544 (L3.2).

Specimens: 22.7 g on deposit at UNM, MMGM holds the main mass.

Bibliography:

Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)

Data from:
  MB107
  Table 0
  Line 0:

Place of purchase:	Tucson
Date:	P 2018
Mass (g):	1326.7
Pieces:	1
Class:	LL3
Shock stage:	S2
Weathering grade:	W1
Fayalite (mol%):	27.2±10.5
Ferrosilite (mol%):	23.6±8.3
Wollastonite (mol%):	0.9±0.5
Classifier:	C. Agee, UNM
Type spec mass (g):	22.7
Type spec location:	UNM
Main mass:	MMGM
Comments:	MVCH-332; submitted by C. Agee, UNM

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)
MMGM: Maine Mineral and Gem Museum, PO Box 500, 99 Main St., Bethel, ME 04217, United States; Website (institutional address; updated 9 Jan 2020)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462

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Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 8402 approved meteorites from (Northwest Africa) (plus 1899 unapproved names)

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