摘要
On September 13, 1977, the Qingzhen enstatite chondrite fell near Qingzhen county,Kweichow Province (26°32'E, 106°28'N). The total recovered mass was 2.6kg in weight. Phenomena of the meteorite fall were recorded as well. In the present paper some of the significant observations are described. X-ray diffraction analyses and petrologic studies have revealed that it is mainly composed of enstatite/clinoenstatite,plagioclase, troilite, kamocite, taenite, quartz and oldhamite. X-ray electron micro.probe analyses have been performed on orthoenstatite and elinoenstatite. Chemical analyses have given the following results: SlO2--36.48; Al2O3--1.64; TiO2--0.08;Cr2O3--0.28 ; FeO--0.30; MnO--0.25 ; MgO--18.19 ; CaO--1.14; No2O--1.06; K2O-0.11;H2O^+--0.47; H2O^-0.10; P2O5--0.39; FeS--13.35; Fe°--22.94; Ni-1.81; Co--0.093;C-0.37; Cu-0.022; Zn-0.027; CaS--0.60 ; total--99.70. This meteorite has been extremely reduced ; all iron is present as FeS and metallic Fe-Ni. The Qingzhen enstatite chondrite is characterized by higher rotio of Si to Mg as compared with ordinary chondrites, scarcity of olivine, and enrichment in surfur and iron. In the thin section, it is observed that rounded chondrules approximately account for 10--15 per cent; being porphyrific, radiating, excentroradial, of excentric fan in shape. Devitrified ehondrules composed of pyroxenes have been also identified. It is postulated from its mineralogy,chemistry and textural characteristics that the Qingzhen meteorite should be assigned to EA-grenp ehondrites.
On September 13, 1977, the Qingzhen enstatite chondrite fell near Qingzhen county, Kweichow Province (26°32' E, 106°28'N). The total recovered mass was 2.6kg in weight. Phenomena of the meteorite fall were recorded as well. In the present paper some of the significant observations are described. X-ray diffraction analyses and petrologic studies have revealed that it is mainly composed of enstatite/clinoenstatite, plagioclase, troilite, kamocite, taenite, quartz and oldhamite. X-ray electron micro-probe analyses have been performed on orthoenstatite and clinoenstatite. . Chemical analyses have given the following results: SiO2-36.48; A12O3-1.64; TiO2-0.08; Cr2O3-0.28; FeO-0.30; MnO-0.25; MgO-18.19; CaO-1.14; Na2O-1.06; K2O-0.11; H2O+-0.47; H2CT- 0.10; P2O5-0.39; FeS-13.35; Fe°-22.94; Ni-1.81; Co-0.093; C-0.37; Cu-0.022; Zn--0.027; CaS-0.60; total-99.70. This meteorite has been extremely reduced; all iron is present as FeS and metallic Fe-Ni. The Qingzhen enstatite chondrite is characterized by higher rotio of Si to Mg as compared with ordinary chondrites, scarcity of olivine, and enrichment, in surfur and iron. In the thin section, it is observed that rounded chondrules approximately account for 10-15 per cent; being porphyrific, radiating, excentroradial, of excentric fan in shape. Devitrified chondrules composed of pyroxenes have been also identified. It is postulated from its mineralogy, chemistry and textural characteristics that the Qingzhen meteorite should be assigned to EA-group chondrites.
出处
《地球化学》
CAS
1977年第4期277-287,315-316,共13页
Geochimica
