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grapevine

Name

*click on the Name for more information

Structure Class

 Carbonaceous chondrites

Chemical Class

CBa

Country

Year found

2021

Mass

550 g

[Museum Collection]

(1) 0.21g   (2) 0.20g   (3) 0.18g   (4) 0.13g

History: On the 6 February 2021, Todd Parker and Robert Ward were searching for gold with metal detectors on Grapevine Mesa, east of Meadview, Mohave County, Arizona. Parker detected a signal, which turned out to be three pieces weighing 252.5 g of a metal-rich meteorite. Together, they recovered 550.3 g in a 2 × 2 m area. Physical characteristics: Exterior of the stones are rusty with patches of fusion crust. Interior of a 4 × 4.5 cm slice shows rounded to angular silicate fragments (to 1 cm) hosted by rounded to anhedral metal grains to 0.7 cm. Metal constitutes 69 areal% of the slice. The metal sizes, shapes, and distribution closely resemble that of Bencubbin. Petrography: A 2 × 1.5 cm polished section shows metal grains composed of micron-sized polycrystalline kamacite containing an abundance of micron-sized troilite blebs and stringers (~1 areal%). Silicates consist of magnesian nonporpyritic silicate fragments with a cataclastic texture. White orange-stained silicate fragments separated by black opaque material hosting sub-mm-sized silicate fragments and rounded troilite and kamacite blebs. Thin terrestrial oxide veins are present around the metal grains. Geochemistry: Oxygen isotopes (K. Ziegler, UNM): Seven fragments analyzed by laser fluorination gave δ18O = 6.949, 5.840, 4.998, 4.541, 5.968, 5.283; δ17O = 3.467, 2.239, 2.456, 1.485, 2.409, 2.091; Δ17O = -0.202, -0.845, -0.183, -0.913, -0.742, -0.699 (linearized, all per mil, TFL slope = 0.528). Average of the seven analyses gives δ18O = 5.596±8.848, δ17O = 2.358±0.646, Δ17O = -0.597±0.323. EPMA (L. Garvie, ASU): Low Ca pyroxene Fs3.17±0.79Wo1.88±2.62 (n=4), Al2O3 = 0.4 to 3.2, TiO2 = 0.1 to 0.2, and Cr2O3 = 0.4 to 0.7 (all wt%); High Ca pyroxene Fs3.37Wo38.45 (n=1), Al2O3 = 7.9, TiO2 = 1.0, and Cr2O3 = 1.5 (all wt%); Olivine Fa3.67 and 4.71; Metal (wt%) Ni = 7.03±0.70, Co = 0.33±0.04, Cr = 0.20±0.09, and P = 0.33±0.04. Classification: The meteorite mineralogically matches that of the subgroup A (CBa) Bencubbin-like carbonaceous chondrites. The oxygen isotopes follow on an extension of the current bencubbinite field. Specimens: Largest mass of 61 g is with Robert RWard. 21 g and a polished mount at ASU.

gujba

*click on the Name for more information

Structure Class

 Carbonaceous chondrites

Chemical Class

CBa

Country

Year found

1984

Mass

100 kg

[Museum Collection]

(1) 41.9g   (2) 26.6g   (3) 13.7g   (4) 11.4g
(5) 11.3g   (6) 9.6g   (7) 9.3g   (8) 7.1g
(9) 6.5g   (10) 3.8g   (11) 3.7g   (12) 3.1g
(13) 3.1g   (14) 2.6g   (15) 2.2g

This is 1 of 9 approved meteorites classified as CBa. Search for specimens in the Smithsonian Institution collection (U.S.): Search for this meteorite in the Natural History Museum collection (U.K.): Published in Meteoritical Bulletin, no. 85, MAPS 36, A293-A322 (2001)

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