from The Meteoritical Bulletin, No. 112
Northwest Africa 15807 (NWA 15807)
Lunar (regolith breccia)
History: The stone was found in Algeria in Februay 2021. It was first purchased by Adam Aaronson from a dealer in Mauritania in November 2021, then sold to Moritz Karl in December 2021 in Tucson, USA.
Physical Characteristics: The stone has a rugged surface with dark patina, with visible white to beige clasts. A cut surface exposes a dark grey interior comprising impact melt, visible metal, numerous angular or more rounded white to light grey lithic clasts and some vugs and weathering products.
Petrography: (R. Zhao, A. Bouvier, UBayr) The type specimen polished section consists of lithic clasts and mineral fragments within a clastic to glassy matrix. Melt rock clasts are generally rounded in shape and dominated by felspathic (anorthitic), and basalt lithologies. Glassy spherules are dominated by anothitic glass. Mineral clasts are angular to more rounded in shape dominated by anorthite, olivine, low-Ca pyroxen, Ca-rich pyroxene, and minor ilmenite, chromite, Fe81Ni13Co6 metal.
Geochemistry: In host matrix, olivines are heterogeneous with Fa32.8±4.4 (Fe/Mn=92±5; n=5) or Fa48.3±1.1 (Fe/Mn=90±6; n=6). Pyroxenes are pigeonite with Fs30.7±1.3Wo12.4±3.8 (Fe/Mn = 55±2, n=5), and augite with Fs23.8±2.0Wo27.3±1.0 (Fe/Mn = 49±2, n=3). An anorthositic clast contains anorthite An95.7±0.7Or0.3±0.2 (n=10). In one melt-rock clast, pyroxene is pigeonite with Fs35.7±1.8Wo12.0±3.7 (Fe/Mn = 57±3, n=10), and feldspathic mesostasis. Oxygen isotopic analyses (R. Greenwood, J. Malley, OU) δ17O=3.316±0.077, δ18O=6.364±0.148, Δ17O=0.006±0.000 (n=2), analyses after leaching ~100 mg sample powders in ethanolamine thioglycolate (EATG).
Classification: Lunar (regolith breccia)
Specimens: 27.8 g including a polished mount at UBayr. Main mass with Achim and Moritz Karl.
I have not studied Northwest Africa 15807.
Meteoritical Bulletin Database