Abstract:

Twenty-three meteorites collected from Blue Ice Area, Grove Mountains, Antarctica have been studied systematically. Observations by laser confocal microscope and determinations by electron probe revealed that neither carbonaceous chondrite nor enstatite chondrite were found among these meteorites. All 23 meteorites studied belong to ordinary chondrites. With the help of energy dispersive X-ray spectrometer installed in SEM large area chemical analytical data of the 23 chondrites were obtained from sections of these samples. According to SiO2 , ∑FeO, MgO and CaO content distribution in the histograms, chemical groups of the 23 chondrites were tentatively divided. On the basis of distribution of olivines and pyroxenes determined by electron probe in the Fa - Fs plot chemical groups of the 23 chondrites were divided, too. The two results for the 23 chondrites are almost identical. Petrologic types for the 23 chondrites are ascertained mainly based on the property of chon-drules and matrix structures of the chondrites, as well as the composition of olivines, structures of pyroxenes and characteristics of feldspars, and so on. But, for the Type 3 of unequilibrated meteorites, its difficult to determine their chemical groups exactly as the mineral composition varies in a large range and probably there is water in the meteorites.