Chemical evolution in the solar nebula based on the chondrite matrix

对EH3球粒陨石（Sahara 97096, 97121, 97158）进行了光学/电子显微镜和拉曼光谱分析。辉石球粒被由低钙辉石、斜长石（玻璃）、富sio相、Fe-Ni金属和troilte组成的细粒边缘所包围。细粒边缘的化学成分与ci球粒陨石相似，但在某些元素上有所不同。这表明太阳星云中的化学分馏是在高度还原的条件下发生的。细粒的边缘含有石墨样物质，显示出可变的拉曼光谱，就像在源自彗星的IDPs中发现的那样。这表明EH3球粒陨石的细粒边缘是由原始和不平衡物质组成的。

Optical/electron microscopy and Raman spectroscopy have been carried out about EH3 chondrites (Sahara 97096, 97121, 97158). There are a pyroxene chondrule surrounded by a fine-grained rim consisting of low-Ca pyroxene, plagioclase (glass), SiO-rich phases, Fe-Ni metal, and troilte. The chemical composition of the fine-grained rim is similar to CI-chondrite but different in some elements. This suggests that chemical fractionation in the solar nebula has occurred under the highly reduced condition. The fine-grained rim contains graphite-like matter showing variable Raman spectra, as found in IDPs that originate from comets. This indicates that the fine-grained rim in EH3 chondrites is composed of primitive and unequilibrated materials.