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A Tiny Piece of Basalt Probably from Asteroid 4 Vesta

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Acta Geologica Sinica(English Edition) 2004年第5期78卷 1025-1033页

作者： linyangting WANGDaode WANGGuiqing InstituteofGeologyandGeophysics ChineseAcademyofSciencesBeijing100090 GuangzhouInstituteofGeochemistry ChineseAcademyofSciencesGuangzhouGuangdong510640

Grove Mountains (GRV) 99018 is a new eucrite (0.23 g), consisting mainly of pyroxene (50.5 vol%) and plagioclase (37.2 vol%) with minor silica minerals (7.0 Vol%) and opaque minerals (5.2 vol%). It was intensely shocked, leading to partial melting, formation of abundant tiny inclusions in pyroxenes and plagioclase, and heavy brecciation. Exsolution of most pyroxenes (1-3μm in width of the lamellae), recrystallization of the shpck-induced melt pockets and veins (5-20μm in size), and homogeneous compositions of pyroxenes of various occurrences suggest the intense thermal metamorphism of GRV 99018 in the asteroidal body Vesta. This new eucrite will bring additional constraints on the chemical composition and multi-stage thermal and shock history of Vesta.

关键词： meteorite basalt eucrite asteroid magmatism shock metamorphism thermal history

Ca-, Al-rich Inclusions in Three New Carbonaceous Chondrites from the Grove Mountains, Antarctica: New Evidence for a Similar Origin of the Objects in Various Groups of Chondrites

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Acta Geologica Sinica(English Edition) 2004年第5期78卷 1042-1051页

作者： DAIDeqiu linyangting MIAOBingkui SHENGWenjie WANGDaode GuangzhouInstituteofGeochemistry ChineseAcademyofSciencesGuangzhouGuangdong510640 InstituteofGeologyandGeophysics ChineseAcademyofSciencesBeijing100029

Three new carbonaceous chondrites (GRV 020025,021579 and 022459) collected from the Grove Mountains (GRV), Antarctica, have been classified as the CM2, CO3 and CV3 chondrites, respectively. A total of 27 Ca- and Al-rich inclusions have been found in the three meteorites, which are the earliest assemblages formed in the solar nebula. Most of the inclusions are intensively altered, with abundant phyllosilicates in the inclusions from GRV 020025 and FeO enrichment of spinel in those from GRV 022459. Except for one spinel-spherule in each of GRV 020025 and 021579, all the inclusions can be classified as Type A-like or spinel-pyroxene-rich inclusions, and they probably represent the continuum of solar nebular condensation. In addition, most of the inclusions in these meteorites share much similarity in both petrography and mineral chemistry, suggesting a similar origin of Ca-Al-rich inclusions in various chondrites.

关键词： Antarctica meteorite carbonaceous chondrite Ca-Al-rich inclusion CAI nebula

A New Martian Meteorite from Antarctica:Grove Mountains (GRV) 020090

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Acta Geologica Sinica(English Edition) 2004年第5期78卷 1034-1041页

作者： MIAOBingkui OUYANGZiyuan WANGDaode JUYitai WANGGuiqin linyangting InstituteofGeologyandGeophysics ChineseAcademyofSciencesBeijing100029 NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012 GuangzhouInstituteofGeochemistry ChineseAcademyofsciencesGuangzhouGuangdong510640 TheSecondBureauofChinaExploration＆EngineeringBureau FuzhouFujian350001

Reported in this paper are the petrology and mineral chemistry of GRV 020090, the second Martian meteorite collected from the Grove Mountains, Antarctica. This meteorite, with a mass of 7.54 g, is completely covered by a black and glazy fusion crust. It has two distinct textural regions. The interstitial region is composed of euhedral grains of olivine, pigeonite, and anhedral interstitial maskelynite, with minor chromite, augite, phosphates and troilite. The poikilitic region consists of three clasts of pyroxenes, each of which has a pigeonite core and an augite rim. A few grains of subhedral to rounded olivine and euhedral chromite are enclosed in the pyroxene oikocrysts. GRV 020090 is classified as a new member of lherzolitic shergottites based on the modal composition and mineral chemistry. This work will shed light on the composition of Martian crust and magmatism on the Mars.

关键词： meteorite lherzolite shergottite achondrite Mars Antarctica

Grove Mountains(GRV)99027:A new Martian meteorite

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Chinese Science Bulletin 2003年第16期48卷 1771-1774页

作者： linyangting WANGDaode MIAOBingkui OUYANGZiyuan LIUXiaohan JUYitai GuangzhouInstituteofGeochemistry ChineseAcademyofSciences(CAS)Guangzhou510640China NationalAstronomicalObservatories CASBeijing100012China InstituteofGeologyandGeophysics CASBeijing100029China

We report the petrography, mineral chemistry and oxygen isotopic composition of GRV 99027, a new Mar-tian meteorite recently collected during the 16th Chinese Antarctic Research Expedition. This meteorite consists of two textural regions. The interstitial region is characterized by the presence of plagioclase and phosphate, and higher FeO contents of olivine and orthopyroxene, in comparison with the poikilitic region. All of the observations are similar to the three known Martian lherzolites. We classify GRV 99027 as the fourth sample of Martian lherzolite.

关键词：矿石化学同位素氧 GRV 99027 火星陨石中国南极科研考察队斜长岩磷酸盐橄榄石

Classification of 24 New Ordinary Chondrites from the Grove Mountains, Antarctica

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Acta Geologica Sinica(English Edition) 2004年第5期78卷 1052-1059页

作者： LURen MIAOBingkui WANGGuiqing DAIDeqiu linyangting OUYANGZiyuan LIChunlai InstituteofGeochemistry ChineseAcademyofSciencesGuiyangGuizhou550002 InstituteofGeologyandGeophysics ChineseAcademyofSciencesBeijing100090 GuanezhouInstituteofGeochemistry.ChineseAcademyofSciences GuangzhouGuangdong510640 NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012

Petrography and mineral chemistry of 24 ordinary chondrites from the Grove Mountains, Antarctica, have been studied in order to identify their chemical-petrographic types. These samples were selected from a total of 4448 Grove Mountains (GRV) meteorites collected during the 19th Chinese Antarctic Research Expedition so as to make an estimation of the large GRV meteorite collection. The chemical-petrographic types of these meteorites are presented below: 1 H3,2 H4, 4 H5, 2 H6, 1 L4, 7 L5, 5 L6, 1 LL4 and 1 LL6. The new data weaken the previous report that unequilibrated ordinary chondrites are unusually abundant in the Grove Mountains region. However, this work confirms significant differences in distribution patterns of chemical-petrographic types between the Grove Mountains and other regions in Antarctica. Many of these meteorites show significant terrestrial weathering, probably due to a high abundance ratio of meteorites found in moraines to those on blue ice. Nine meteorites experienced severe shock metamorphism, as evidenced by undulose extinction and intense fracturing of silicates and presence of shock-induced melt veins and pockets. These heavily shocked meteorites provided us with natural samples for the study of high-pressure polymorphs of minerals.

关键词： Antarctica meteorite ordinary chondrite classification shock metamorphism thermal metamorphism