对南极类C1陨石成因和星云水化作用范围的几点看法

南极陨石的研究发现，有几个碳质球粒陨石富含与Ｃ１陨石类似的含水层状硅酸盐集合体及其角砾．其氧同位素比值也与Ｃ１接近，因而称之为类Ｃ１陨石。类Ｃ１陨石与Ｃ１陨石的区别是：类Ｃ１陨石中的含水层状硅酸盐既以基质的形式产出，也出现在球粒中；类Ｃ１陨石中含有球粒及有关组分，如球粒碎块、矿物集合体等。每个陨石中所含这些组分的数量不同，其矿物的成分也差别很大，从而说明它们形成的星云环境不同。因此笔者认为类Ｃ１陨石可能是小行星区星云盘外层的星云凝聚物受到不同程度水化作用后吸积形成的陨石。

A DISCUSSION ON SOME ANTARCTIC QUASI C1 CHONDRITES ORIGIN AND RANGE OF NEBULAR HYDROUS EFFECT

Because of containing many phyllosilicate aggregates and similar oxygen isotopic com-position to C1 carbonaceous chondrite,the Antarctic carbonaceous chondrite,Y 82162,Y 86720,Belgica 7904,PCA 91082,Y 793495,and Y 8449 are called as quasi-C1chondrite. In these carbonaceous chondrites the phyllosilicate aggregates exist as fourforms:(1)matrix,(2)clast with same composition of matrix,(3)chondrule,(4)dark Inclu-sion. This four forms are independence relatively in meteorite,so the hydrous effect musttake place after nebular condensation and before meteorite parent body formation,Besidesphyllosilicate aggregates ,some higher temperature condensates or their remainder,for ex-ample ,non -completely hydrous chondrite,anhydrous silicate mineral and their aggregate,appear in these meteorites.In different meteorite the composations of higher temperaturecondensate remainder are various,from enstatite,silica mineral,to moderate Fe-rich o-livine,Fe-rich olivine. According to above evidences and this fact that water has been ob-served on Mar,Earth and Mercury,we consider that range of nebular hydrous effect couldbe wide,including terrestrial planet region and asteroids region of solar nebular.