NEW MARS, LUNAR METEORITES
The Meteoritical Bulletin below describes three new Mars meteorites and six new lunar meteorites. However, the number of Mars meteorites remains at 27 due to prior announcements and pairings. DaG 975 is presumed paired with the DaG 467, 489, 670, 735 and 876 set. NWA 998 and NWA 1195 were announced last May by the University of Washington: http://www.jpl.nasa.gov/snc/news48.html Ron Baalke ------------------------------------------------------------------- THE METEORITICAL BULLETIN E-mail Announcement 87-1, January 28, 2003 Sara Russell, Editor ([EMAIL PROTECTED]) Jutta Zipfel, Assoc. Ed. for Northwest Africa ([EMAIL PROTECTED]) Luigi Folco, Assoc. Ed. for Africa ([EMAIL PROTECTED]) Monica Grady, Assoc. Ed. for Oman ([EMAIL PROTECTED]) Rhian Jones, Assoc. Ed. for the Americas ([EMAIL PROTECTED]) Tim McCoy, Assoc. Ed. for Antarctica ([EMAIL PROTECTED]) Jeffrey N. Grossman, Assoc. Ed. for Web ([EMAIL PROTECTED]) This is the first electronic announcement of new meteorites to be published in Meteoritical Bulletin, No. 87, 2003 July. Here, you will find the complete text of announcements of newly described martian and lunar meteorites. Martian meteorites described below: Dar al Gani 975 Basaltic shergottite (Libya) Northwest Africa 998 Nakhlite (Algeria or Morocco) Northwest Africa 1195 Basaltic shergottite (Northwest Africa) Lunar meteorites described below: Dhofar 304 anorthositic impact melt breccia (Oman) Dhofar 305 anorthositic impact melt breccia (Oman) Dhofar 306 anorthositic impact melt breccia (Oman) Dhofar 307 anorthositic impact melt breccia (Oman) Dhofar 308 anorthositic impact melt breccia (Oman) Dhofar 490 anorthositic fragmental breccia (Oman) The preliminary text of the 2003 Meteoritical Bulletin, including the above meteorites, may by viewed at: http://www.meteoriticalsociety.org/bulletin/mb87.pdf ***PLEASE REPORT ERRORS TO THE EDITORS BY 1 APRIL 2003 All information in this e-mail and on the above-cited Meteoritical Bulletin webpage is subject to revision until final publication in the summer of 2003. ================================================================ ANNOUNCEMENTS ================================================================ Dar al Gani 975 27°19.63' N, 16°13.00' E Libya Found 1999 August 21 Martian meteorite (basaltic shergottite) A 27.55 g stone was found on 1999 August 21 in the sand desert of Dar al Gani. Classification and mineralogy (A. Greshake, MNB, and M. Kurz, Kurz): a basaltic shergottite with porphyritic texture; large chemically zoned olivine phenocrysts are set into a fine-grained groundmass consisting mostly of pyroxene and maskelynite; minor phases include chromite, Ti-rich chromite, sulfides, phosphates, and small Fe-rich olivines; olivine phenocrysts often contain melt inclusions, small chromites and exsolution lamellae; pyroxenes are mostly chemically zoned pigeonites, some contain orthopyroxene cores; olivine phenocrysts, Fa24.3-38.3; pigeonite, Fs21.1-29Wo5.9-13.8; orthopyroxene, Fs17.4-21.8Wo1.8-3.4; augite, Fs18.5Wo34; matrix olivine, Fa35.9-39.8; maskelynite, An66.5-71.4; shock stage, S4; contains melt veins and melt pockets; low degree of weathering. Possibly paired with DaG 467, 489, 670, 735 and 876. Specimens: main mass with anonymous finder; type specimen, 8.5 g, plus one polished thin section MNB. Dhofar 304 18°24.2'N, 54°09.0'E Oman Found 2001 April 13 Lunar meteorite (anorthositic impact melt breccia) A brownish grey stone weighing 10 g was found in the Dhofar region, Oman. Mineralogy and classification (M. Nazarov, Vernad, L. Taylor, UTenn): fusion crust is absent; meteorite is a clast-rich impact melt breccia; mineral fragments and lithic clasts are embedded in a very fine-grained impact-melt matrix; the lithic clast population is dominated by impact melt breccias; possible igneous rocks and granulites of mostly anorthositic and gabbro-noritic compositions are rare. Mineral compositions are: feldspar, An93-99; orthopyroxene, Wo1- 5En70-90; clinopyroxene, Wo6-42En40-50; olivine, Fo60-90 (Fe/Mn ˜ 87 at). Accessory minerals are Ti-rich chromite, Cr-pleonaste, ilmenite (7-8 wt % MgO), troilite, and FeNi metal (7.8 wt% Ni; 0.6 wt% Co). The composition of the impact-melt matrix (wt%) is SiO2 = 45.0, TiO2 = 0.34, Al2O3 = 25.3, Cr2O3 = 0.17, FeO = 5.71, MnO = 0.12, MgO = 7.09, CaO = 14.8, Na2O = 0.37, K2O = 0.04, P2O5 = 0.07. The meteorite is moderately weathered; gypsum, calcite, celestite, barite, and Fe hydroxides occur in cracks and holes. Dhofar 304 is possibly paired with Dhofar 025 and Dhofar 301 because the stones were found nearby, and they are similar in texture, mineral chemistry and degree of weathering. Specimens: type specimens of 2 g, and a thin section, Vernad; main mass with anonymous finder. Dhofar 305 19°19.8'N, 54°47.0'E Oman Found 2001 June 28 Lunar meteorite (anorthositic impact melt breccia) A light-grey stone weighing 34.11 g was found in the Dhofar region of Oman. Mineralogy and classification (M. Nazarov, Vernad, L. Taylor, UTenn): fusion crust is absent; the meteorite is an impact melt breccia consisting of mineral fragments and lithic clasts set within fine-grained, well-crystallized impact-melt matrix; clasts of impact melt breccias are most common; granulites and possible igneous rocks are rare and have mainly anorthositic and troctolitic compositions; orthopyroxenite clasts are present; feldspar, An87-98; orthopyroxene, Wo1-5En40-88; clinopyroxene; Wo6-48En30-70; olivine, Fo44-90 (Fe/Mn = 94 at); accessory minerals are Ti-rich chromite, Cr-pleonaste, ilmenite (1-8 wt % MgO), armalcolite, troilite, and FeNi metal (17-32 wt% Ni; 1.3-2.3 wt% Co); composition of the impact-melt matrix is (wt%) SiO2 = 43.9, TiO2 = 0.16, Al2O3 = 28.5, Cr2O3 = 0.10, FeO = 3.69, MnO = 0.07, MgO = 6.08, CaO = 15.9, Na2O = 0.36, K2O = 0.02, P2O5 = 0.04 (wt%); the stone is moderately weathered; calcite, celestite, gypsum, and Fe hydroxides are present. Dhofar 305 is close to Dhofar 303, which was found nearby, in degree of weathering, mineral chemistry, and matrix composition. The meteorites may be paired but they are very different in texture. Pairing with Dhofar 081/280, 302, 306 and 307 is also possible. Specimens: type specimens of 7 g, and a thin section, Vernad; main mass with anonymous finder. Dhofar 306 19°19.7'N, 54°47.1'E Oman Found 2001 June 29 Lunar meteorite (anorthositic impact melt breccia) A light-grey stone weighing 12.86 g was found in the Dhofar region of Oman. Mineralogy and classification (M. Nazarov, Vernad, L. Taylor, UTenn): fusion crust is absent; the meteorite is an impact melt breccia consisting from mineral fragments and lithic clasts cemented by fine-grained impact-melt matrix; clast population is dominated by impact melt breccias; granulites and cataclastic igneous rocks of anorthositic, troctolitic and noritic compositions are present; devitrified glass fragments occur also; a characteristic feature of the lithic clast population is abundant high mg# lithologies; feldspar, An93-98; orthopyroxene, Wo1-5En50-90; clinopyroxene; Wo10- 48En30-75, olivine, Fo48-94 (Fe/Mn = 87 at); accessory minerals are Ti-rich chromite, Cr-pleonaste, ilmenite (3-8 wt% MgO), armalcolite, silica, Ca-phosphate, troilite, and FeNi metal (7-68 wt% Ni, 0.3-3.4 wt% Co); composition of the impact-melt matrix is SiO2 = 44.0, TiO2 = 0.15, Al2O3 = 27.2, Cr2O3 = 0.12, FeO = 4.00, MnO = 0.05, MgO = 7.55, CaO = 15.5, Na2O = 0.33, K2O = 0.04, P2O5 = 0.07 (wt%); the stone is moderately weathered; celestite, calcite and Fe hydroxides are present. Dhofar 306 is different in texture and mineral chemistry from Dhofar 081/280, 302, 303, 305 and 307, which were found nearby. However the meteorites may be paired. Specimens: type specimen, 2.6 g and a thin section, Vernad; main mass with anonymous finder. Dhofar 307 19°19.7'N, 54°46.9'E Oman Found 2001 April 14 Lunar meteorite (anorthositic impact melt breccia) A light-grey stone weighing 50 g was found in the Dhofar region of Oman. Mineralogy and classification (M. Nazarov, Vernad, L. Taylor, UTenn): fusion crust is absent; the meteorite is an impact melt breccia; fine-grained impact melt is most abundant; mineral fragments and rare lithic clasts of anorthositic, troctolitic, and gabbro- noritic compositions occur in the impact-melt matrix; the presence of rare dunite fragments is a characteristic feature of the meteorite; glass veins are common; feldspar, An89-98; orthopyroxene, Wo1-5En50- 90; clinopyroxene; Wo6-48En40-75;, olivine, Fo38-94 (Fe/Mn = 92 at); accessory minerals are Ti-rich chromite, Cr-pleonaste, ilmenite (2-6 wt % MgO), troilite, and FeNi metal (8-49 wt% Ni, 0.3-2.0 wt% Co); composition of the glass veins is SiO2 = 43.8, TiO2 = 0.09, Al2O3 = 30.8, Cr2O3 = 0.09, FeO = 2.58, MnO = 0.05, MgO = 4.06, CaO = 17.3, Na2O = 0.36, K2O = 0.01, P2O5 = 0.02 (wt%); the stone is moderately weathered; calcite, gypsum, celestite, barite, and Fe hydroxides are present. Dhofar 307 is most similar in texture and mineral chemistry to Dhofar 305, found nearby. The meteorites are likely to be paired. Pairing with Dhofar 081/280, 302, 303, and 306 is also possible. Specimens: type specimen, 10 g and a thin section, Vernad; main mass with anonymous finder. Dhofar 308 is a 2 g stone paired with Dhofar 025, 301 and 304. Dhofar 490 18°43.00'N 54°27.00'E Oman Found 2001 March 17 Lunar meteorite (anorthositic fragmental breccia) A dark grey, crusted stone weighing 34.05 g was found in the Dhofar region of Oman. Classification and mineralogy (A. Greshake, MNB and M. Kurz, Kurz): meteorite is an anorthositic fragmental breccia consisting of clasts of various lithologies embedded into a glassy, partly devitrified fine-grained matrix; the clast size is generally below 3 mm; vesicles are abundant; feldspar: An96.0-99.3; pyroxene: Fs11.5-35.7Wo8.2-44.9 and olivine: Fa30.6-50.0; augites dominate over Ca-poor pyroxenes and often contain pigeonite exsolution lamellae; accessory phases are Fe-Ni metal and ilmenite; crystalline fragments include microporphyritic impact melt breccias, intersertal impact melt clasts, gabbroic anorthosites, and large feldspar; no mare basalt clasts and no glass spherules have been identified; feldspar generally shows pronounced undulatory extinction and sometimes mosaicism indicating strong shock metamorphism; the meteorite is moderately weathered; gypsum, celestite and calcite occur in cracks and holes; Dhofar 490 may be paired with Dhofar 280 since they were found nearby and have similar mineralogical characteristics; specimens: 7 g and one thin section, MNB; main mass with anonymous finder. Northwest Africa 998 Algeria or Morocco Purchased 2001 September Martian meteorite (nakhlite) A. and G. Hupé (Hupé) purchased from dealers at the Tucson Gem and Mineral Show in 2002 February the main mass from a 456 g stone that had been acquired at an unspecified site in western Algeria or eastern Morocco in 2001 September. Dimensions before cutting: 72 mm by 65 mm by 48 mm. Classification and mineralogy (A. Irving and S. Kuehner, UWS): a friable, dark green rock with minor orange-brown alteration products that probably are of pre-terrestrial origin. It is composed mainly of subhedral, olive-green, complexly zoned subcalcic augite (Fs22Wo39) with subordinate yellow olivine (Fa64), orthopyroxene (Fs49Wo4), interstitial plagioclase (Ab61Or4 containing 0.1 wt% SrO, and exhibiting normal birefringence), titanomagnetite, chlorapatite and pyrrhotite. The overall texture is that of a hypabyssal, adcumulate igneous rock, and the apparent crystallization sequence is olivine, orthopyroxene, titanomagnetite, augite, apatite, plagioclase. There is a weak preferred orientation of prismatic pyroxene crystals, many of which have very distinctive zoning, with cores of augite surrounded by irregular, inverted pigeonite rims (now consisting of orthopyroxene with fine augite lamellae). Trains of tiny melt inclusions are present along healed fractures within pyroxene; microprobe study confirms that most of these are K-Na-Al- bearing silicate glass, but some are intergrowths of glass and Fe- bearing carbonate, which may represent quenched immiscible silicate- carbonate liquids. Symplectitic intergrowths of titanomagnetite and low-Ca pyroxene are present at grain boundaries between large, discrete olivine and titanomagnetite grains, but are not present around chromian titanomagnetite inclusions within olivine. These observations suggest that a pre-terrestrial oxidation process produced the symplectites, and involved high temperature, deuteric fluid infiltration along grain boundaries; such fluids also may have produced the irregular pigeonitic rims on augite crystals. Secondary (probably pre-terrestrial) ankeritic carbonate, K-feldspar (some Fe- bearing), serpentine (?), calcite and a Ca sulfate are present on grain boundaries and within cracks in augite. Oxygen isotopes (D. Rumble, CIW): replicate analyses of acid-washed augite by laser fluorination gave d18O = +3.9 +/- 0.2, d17O = +2.4 +/- 0.1, D17O = +0.30 +/- 0.02 permil. Specimens: type specimens, 20 g, UWS, 20 g, FMNH, and two polished thin sections, UWS; main mass, Hupé. Northwest Africa 1195 Morocco Purchased 2002 March/April Martian meteorite (basaltic shergottite) A. and G. Hupé (Hupé) purchased a 50 g fragment of a broken stone with a distinctive, thin weathering rind collected by nomads near Safsaf, Morocco in 2002 March, and subsequently purchased the remainder of the same elongated stone (total weight 315 g). Dimensions of the reassembled stone are 133 mm x 43 mm x 37 mm. Classification and mineralogy (A. Irving and S. Kuehner, UWS): olivine megacrysts (up to 4 mm) are set in a groundmass of low-Ca pyroxene and maskelynite (Ab37Or0.5 to Ab41Or0.7) with minor Ti- chromite, pyrrhotite, ilmenite and Mg-bearing merrillite. The euhedral to subhedral shapes of most of the olivine grains suggest that they are phenocrysts rather than xenocrysts. Olivine exhibits strong compositional zoning (cores Fa19, FeO/MnO = 54; rims Fa40, FeO/MnO = 62), and contains abundant inclusions of chromite, clinopyroxene, orthopyroxene and pyrrhotite. The groundmass low-Ca pyroxenes are zoned from cores of pigeonite (Wo7Fs26, FeO/MnO = 37.1) or, less commonly, orthopyroxene (Wo4Fs23, FeO/MnO = 37.0) to rims of more Fe-rich pigeonite (Wo12Fs33, FeO/MnO = 36.6). Occurring very rarely on groundmass pyroxene grains are patchy overgrowths of an Fe- rich mineral (possibly related to chamosite or chlorite, with 35 wt% FeO, 5 wt% Al2O3, 1.5 wt% MgO and a low oxide sum of 85 wt%, suggesting the presence of water or hydroxyl). Calcite occurs sparsely along grain boundaries and as thin veinlets. Texture and mineral compositions are similar to those in olivine-phyric basaltic shergottite DaG 476/670, but olivine is much more magnesian than in other olivine-phyric basaltic shergottites Sau al Uhaymir 005/008 and Northwest Africa 1068/1110. Specimens: type specimen, 20 g, and two polished thin sections, UWS; main mass, Hupé. ================================================================ ADDRESSES OF METEORITE COLLECTIONS AND RESEARCH FACILITIES ABBREVIATED ABOVE MAY BE FOUND ON-LINE AT http://www.meteoriticalsociety.org/bulletin/mb87.pdf. ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
