Lunar Meteorite: Tisserlitine 001 & Northwest Africa 13621

Presumed paired stones

End cut of Tisserlitine 001 . Photo credit: ?
Some photos of slices of Tisserlitine 001 that I found on the internet. Photo credit: ?
More photos of Tisserlitine 001 that I found on the internet. Photo credit: ?
A 3.4-g stone of Northwest Africa 13621. Photo credit: John Higgins
A 9.4-g endcut of of Northwest Africa 13621. Photo credit: John Higgins

from The Meteoritical Bulletin, No. 109

Tisserlitine 001

Gao, Mali
Find: 2019 December
Mass: 57.41 kg (many pieces)

Classification: Lunar meteorite (feldspathic breccia)

History: Beginning in December 2019 many similar dark stones were found together in the Kidal region of Mali, close to the border with Algeria. One very large stone (40026 g), another stone (4037 g) and 44 smaller stones (combined weight 3642 g) (total weight 47705 g) were purchased by Aziz Habibi in January 2020 from an Algerian dealer and subsequently acquired by Darryl Pitt. Independently, ten other stones of the same distinctive material (combined weight 8536 g) plus many smaller fragments (combined weight 1169 g) were purchased by Mbark Arjdal in February and March 2020 from a relative of the same Algerian dealer.

Physical characteristics: All specimens (many of which have a flattened slab-like form) lack fusion crust and exhibit medium-brown, “knobby” exterior surfaces. Interiors of stones have an overall tan to pinkish hue with obvious light gray, dark gray and whitish clasts plus some visible small grains of metal.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Two separate endcut specimens were studied. Both are samples of the same breccia material, composed of mineral clasts of anorthite, olivine, pigeonite, subcalcic augite, augite and orthopyroxene, plus sparse lithic clasts of spinel troctolite, set in a fine grained microvesicular matrix containing accessory altered kamacite, troilite, taenite and pentlandite. Secondary calcite is present pervasively in one of the two specimens studied and in places may be replacing original glass. Olivine grains in both studied specimens have been partially replaced by inhomogeneous phyllosilicate-rich assemblages, which apparently are hydroxylated (as evidenced by systematically low oxide analytical sums of 88-90 wt.% and absence of measurable F and Cl), and which are very Mn-deficient (yielding very elevated FeO/MnO ratios in the range 150-250). Troctolitic clasts are composed predominantly of anorthite and olivine with accessory Cr-pleonaste, low-Ca pyroxene and/or higher-Ca pyroxene.

Geochemistry: Olivine (Fa17.3-32.1, FeO/MnO = 76-100, N = 15), anorthite (An95.4-99.0Or0.2-0.0, N = 7), pigeonite (Fs18.2-26.8Wo12.4-4.7, FeO/MnO = 47-54, N = 6), orthopyroxene (Fs16.0-21.6Wo2.2-3.7, FeO/MnO = 51-66, N = 4), subcalcic augite (Fs15.9Wo31.0, FeO/MnO = 41), augite (Fs7.6-7.9Wo42.9-45.6; Fs13.8Wo38.9; FeO/MnO = 36-48, N = 3). Troctolite clast: olivine (Fa18.2-21.2, FeO/MnO = 84-92, N = 4), anorthite (An97.7Or0.0), pleonaste (mg = 0.721, cr = 0.093).

Classification:  Lunar (feldspathic regolithic breccia, partially hydrothermally-altered).

Specimens: 37.6 g in the form of two polished endcuts at UWB; remainder with DPitt and Mr. M. Arjdal.

from The Meteoritical Bulletin, No. 109

Northwest Africa 13621 (NWA 13621)

Mali
Purchase: 2020 January-September
Mass: 1608 g (50 pieces)

Classification: Lunar meteorite (feldspathic breccia)

History:  Additional stones (total 49 pieces) very similar to the unusual and distinctive specimens classified as Tisserlitine 001, and which were recovered at the same location in Mali, were acquired from several dealers by John Higgins (500 g), Fabien Kuntz (311 g), Dirk Ross (407 g), and an Algerian team represented by David Lehman (390 g). Comparative assessment and analyses of samples from each of these batches of stones were conducted to confirm their pairing with the previous material.

Physical characteristics: Most of the specimens have a flattened slab-like form and all have distinctive medium-brown, “knobby” exterior surfaces coated by desert patina. Interiors of stones are multi-colored (pink, tan, gray) with some darker gray and white clasts and small grains of metal.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL)  Breccia composed of mineral clasts of anorthite, olivine, augite and pigeonite, plus sparse lithic clasts of microcrystalline anorthosite with fine grained mafic phases, are set in a fine grained microvesicular matrix containing accessory altered kamacite, troilite and rare pentlandite together with secondary calcite and barite. Olivine grains have been partially replaced by inhomogeneous phyllosilicate-rich assemblages characterized by systematically low oxide analytical sums (89-94 wt.% ) and deficiency in manganese (yielding elevated FeO/MnO ratios of 119-122).

Geochemistry: Olivine (Fa24.5-40.6, FeO/MnO = 77-98, N = 7), pigeonite (Fs20.6-24.0Wo5.8-6.8, FeO/MnO = 46-50, N = 3), augite (Fs14.1-14.4Wo37.3-41.4, FeO/MnO = 50-54, N = 3), anorthite (An94.6-97.5Or0.0-0.1, N = 3).

Classification: Lunar (feldspathic regolithic breccia, partially hydrothermally-altered). The colors, textures, mineral compositions and distinctive secondary alteration in these specimens establish beyond doubt that they are paired stones to Tisserlitine 001.

Specimens: 22.2 g including a polished endcut and one polished mount at UWB; 25 g plus one polished thin section at PSF; remaining material with Mr. J. Higgins, Kuntz, Mr. D. Ross and Mr. D. Lehman.

Randy Says…

I have not studied Tisserlitine 001. I assume the stones are paired on the basis of the descriptions. I assume that it is a new meteorite because of the unique description and find location.

More Information

Meteoritical Bulletin Database

Tisserlitine 001 | NWA 13621