Relict grains in chondrules
Relict grains in chondrules
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球粒中的残余颗粒
作者：
E. Rambaldi
没有被广泛认识到的是，普通陨石的球粒中有很大一部分含有硅酸盐颗粒，这些颗粒在球粒形成过程中没有熔化。在最典型的情况下，这些颗粒包括粗橄榄石，很少斜方辉石，晶体位于球粒的核心，并显示分区是不一致的结晶从硅酸盐熔体。周围的基质含有丰富的玻璃和细粒自形橄榄石，似乎是火成的起源。残留的颗粒仍然保留着太阳星云中发生的过程的印记，在某些情况下，可能包括星际颗粒的同位素记录。这些球粒的原始性质在最不平衡的普通球粒中保存得最好1 -3。我在这里提出的重要信息，球粒前体材料和球粒形成的过程中获得的组成和纹理研究的三个最不平衡的3型普通的球粒陨石。
It is not widely recognized that a significant fraction of the chondrules from ordinary chondrites contain silicate grains that survived the chondrule formation process without melting. In the most typical case these grains consist of coarse olivine, rarely orthopyroxene, crystals located in the core of chondrules and displaying a zoning that is inconsistent with crystallization from a silicate melt. The surrounding groundmass contains abundant glass and fine grained euhedral olivines that appear to be of igneous origin. The relict grains still preserve the imprint of processes that occurred in the solar nebula and, in some cases, may include the isotopic record of interstellar grains. The original properties of these chondrules are best preserved in the most unequilibrated ordinary chondrites1–3. I present here important information with regard to the chondrule precursor materials and the process of chondrule formation which was acquired by a compositional and textural study of three of the most unequilibrated type 3 ordinary chondrites.