The Formation of Chondrules and Chondrites and Some Observations on Chondrules from the Tieschitz Meteorite
The Formation of Chondrules and Chondrites and Some Observations on Chondrules from the Tieschitz Meteorite
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球粒和球粒陨石的形成以及对蒂希茨陨石球粒的一些观测
DOI：
10.1007/978-94-010-3411-1_17
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发表时间：
1969
期刊：
影响因子：
--
通讯作者：
G. Kurat
中科院分区：
文献类型：
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作者：
G. Kurat
对铁希茨陨石和梅佐-马达拉斯陨石中几个球粒的共存矿物和填隙基质的分析表明，这些球粒是几个复杂和重叠过程的产物。将这些陨石球粒与来自这些陨石和其他陨石的所谓“平衡”陨石球粒进行比较，可以清楚地看出所谓“非平衡”陨石球粒是在特殊环境下形成的。它们可能代表球粒形成的一般过程的边界相。通过热变质作用从“不平衡”球粒形成“平衡”球粒被认为是不可能的。铁希茨陨石没有显示出变质的迹象。尽管如此，有几个陨石球粒显示出一些变化，这些变化在它们凝聚之后显然是持续的。某些过程-可能是循环水或水蒸气-导致霞石和长石成分的选择性溶解，溶解主要发生在表面附近以及细粒辉石球粒和玻璃球粒的沿着裂缝处。未观察到该材料的再沉积。
Analyses of coexisting minerals and interstitial groundmass in a few chondrules of the Tieschitz and Mezo-Madaras chondrites show that these chondrules are the products of several complex and overlapping processes. Comparison of these chondrules with so-called ‘equilibrated’ chondrules from these and other meteorites makes clear that the chondrules of the so-called ‘unequilibrated’ chondrites have been formed under special circumstances. Probably they represent a border-facies of the ordinary process of chondrule formation. Formation of ‘equilibrated’ chondrules from ‘unequilibrated’ ones through thermal metamorphism is thought to be impossible.The Tieschitz meteorite shows no sign of metamorphism. In spite of this, several chondrules display some alterations which they clearly sustained after their agglomeration. Some process - probably circulating water or water vapour - led to selective dissolution of the nepheline and feldspar component, mainly near the surface and along cracks in finegrained pyroxene chondrules and glass-bearing chondrules. No redeposition of this material has been observed.