Concentrations of Cr, Co, Ni, Cu, Ga, Ge, As, Sb, W, Re, Ir, Pt and Au of two ungrouped iron meteorites, Grove Mountains (GRV) 98003 from Antarctica and Ujimqin, were measured using instrumental neutron activation analysis. According to the bulk chemistry, GRV 98003 is classified as a member of lAB group,and Ujimqin as a unique one of IAB iron meteorite complex. The elemental abundance pattern and correlation between elements (e. g. Ni-Au, Co-Au, As-Au, W-Au, Cu-Au, Sb-Au) of GRV 98003 are similar with those of NAW 468 (IAB), but significantly depleted in refractory siderophile elements (Re, It) and moderate volatile elements (Ga, Ge) relative to the latter. In addition, we reclassify Nantan (Ⅱ-ICD) as a member of IAB main group (MG) and Yongning (IA) as a unique iron meteorite related with IAB iron meteorite complex.
Hydrogen isotopic composition was measured using an ion microprobe for lherzolitic shergottite in Martian meteorite GRV 99027 from the Grove Mountains in Antarctica. The D/H ratios of phosphate whitlockites were analyzed and water concentrations of tested points were calculated. The result show that their δ D values vary from +1300‰ to +4700‰, and water contents from 0.04 wt% to 0.43 wt%. Comparing the results with the hydrogen isotopic compositions of whole rock, hydrous miner- als and phosphates in SNC meteorites indicates that water highly enriched in deuterium is a unique feature of Martian meteorites, especially the phosphates prominent. It is interpreted as the result of isotopic exchange between magmatic water and Martian crustal fluids. The high D/H ratios observed in GRV 99027 phosphates indicate that they have hydrogen isotopic compositions similar to those of apatite in other Martian meteorites. The results further con- firmed the association of GRV 99027 with the Martian meteorite group.
Reported in this paper are the petrology and mineral chemistry of GRV 020090,the second Martian meteorite coll...
MIAO Bingkui~(1,2),OUYANG Ziyuan~3,WANG Daode~4,JU Yitai~5, WANG Guiqin~4 and LIN Yangting~1 1 Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029
We have determined the concentrations of 10Be and 26Al in GRV 99027 recovered by the 16th Chinese Antarctic expedition team, which are 14.1 ± 0.6 dpm/kg and 67.5 ± 3.4 dpm/kg, respectively. From the concentration of 10Be, we calculate a cosmic-ray exposure age of 4.4 ± 0.6 Ma for GRV 99027. The concentration of 26Al is too high compared to the 10Be exposure age, indicating extra production from solar ray. The exposure ages, petrologic and geochemical characteristics of mantle-derived Martian meteorites GRV 99027, LEW 88516, Y-793605, NWA 1950 and ALHA77005 are very similar, suggesting that these meteorites most probably were ejected from Mars in the same impact event.
