Lunar Meteorite: Aridal 019 & 020
possible paired stones
| from The Meteoritical Bulletin, No. 111 Aridal 019Rio de Oro, Western Sahara Lunar meteorite (feldspathic breccia) History: Five similar-appearing stones were found together. Physical Characteristics: One large stone (1207 g) plus four smaller stones (total 161 g). All stones exhibit a brown, knobby exterior with light desert patina; cut interior surfaces reveal small white to beige clasts within a fine grained tan matrix. Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Fine grained breccia composed of mineral clasts of anorthite, altered olivine, low-Ca pyroxene, pigeonite and augite in a very fine grained matrix containing low-Ti, high-Al chromite, ilmenite and minor secondary barite. Most olivine has been completely altered to an iddingsite-like hydrous phase with low oxide sums and elevated FeO/MnO ratios; this is very similar to the altered olivine documented in paired lunar meteorites Tisserlitine 001 and NWA 13621. Geochemistry: Anorthite (An95.9-97.7Or0.1, N = 3), low-Ca pyroxene (Fs28.5-35.0Wo2.0-4.5, FeO/MnO = 60-71, N = 4), pigeonite (Fs31.0-31.9Wo8.1-8.9, FeO/MnO = 57-60), augite (Fs20.1-21.9Wo39.6-35.1, FeO/MnO = 51-53, N = 2), unaltered olivine (Fa39.3, FeO/MnO = 92, N = 1). Classification: Lunar (feldspathic breccia). Although this material has some mineralogical similarities to Tisserlitine 001 and NWA 13621 found in eastern Mali, these stones have a different external appearance and the find site is reliably at a location much farther to the west. Specimens: 22.4 g including one polished endcut at UWB; remainder with Mr. T. Boudreaux. |
| from The Meteoritical Bulletin, No. 112 Aridal 020Rio de Oro, Western Sahara Lunar meteorite (feldspathic breccia) History: Found in southern Morocco and purchased by Ziyao Wang in November 2022 from a dealer in Ouarzazate, Morocco. Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Breccia composed of fairly closely-packed mineral clasts of anorthite, olivine, low-Ca pyroxene, pigeonite, subcalcic augite and augite in a sparse fine-grained matrix containing medium-Ti chromite, ilmenite, kamacite, minor schreibersite (as composite grains with kamacite) and rare silica polymorph. Secondary terrestrial phases are barite and a fibrous chlorite-like phyllosilicate phase with low oxide sums and elevated FeO/MnO ratios replacing some primary olivine. Geochemistry: Olivine (Fa37.2-43.3, FeO/MnO = 91-96, N = 3), low-Ca pyroxene (Fs18.9Wo3.0, FeO/MnO = 51), pigeonite (Fs22.9-29.7Wo6.2-8.4, FeO/MnO = 50-54, N = 2), subcalcic augite (Fs17.8Wo25.6, FeO/MnO = 39), augite (Fs8.8Wo44.1, FeO/MnO = 34), anorthite (An93.6-97.2Or0.2-0.0, N = 3). Classification: Lunar (feldspathic breccia). Specimens: 21.1 g including a polished slice at UWB; remainder with WangZ. |
| Randy Says… These two meteorites may be paired. The strongest evidence is the descriptions of the olivines and the fact that they were found 6.3 km apart,. |