Post-hydration thermal metamorphism of carbonaceous chondrites
Post-hydration thermal metamorphism of carbonaceous chondrites
复制标题
碳质球粒陨石的水化后热变质作用
DOI：
10.2465/jmps.100.260
复制
发表时间：
2005
影响因子：
0.7
通讯作者：
Tomoki Nakamura
中科院分区：
文献类型：
--
作者：
Tomoki Nakamura
许多碳质球粒陨石中存在丰富的层状硅酸盐，这表明原始小行星中普遍存在低温水蚀变活动。然而，在已知的含水碳质球粒陨石中，超过 20 个样品显示出在高温下加热并导致相应页硅酸盐脱水的证据。脱水的矿物学特征表明，加热发生在陨石的原位，这表明存在一些水合小行星在水蚀变后的一定时期内被加热。最近的研究揭示了含水碳质球粒陨石加热和脱水过程的细节：矿物学、微量元素化学、碳质材料和反射光谱的逐步变化已得到澄清。根据基体的同步加速器X射线衍射分析数据，加热的含水碳质球粒陨石被分为I-IV阶段，加热温度从I增加到IV。尽管最近取得了进展，但热源的定义仍不明确，主要是由于缺乏有关加热时间的年代信息，因此需要更多数据来充分阐明含水碳质球粒陨石的热变质作用。
The presence of abundant phyllosilicates in many carbonaceous chondrites indicates a prevailing activity of low-temperature aqueous alteration in primitive asteroids. However, among the hydrous carbonaceous chondrites known, more than 20 samples show evidence of having been heated at elevated temperatures with corresponding phyllosilicate dehydration. The mineralogical features of dehydration suggest that the heating occurred in situ in meteorites, which demonstrates that there are some hydrated asteroids that have been heated at a certain period after aqueous alteration. Recent studies have uncovered details of heating and dehydration processes in hydrous carbonaceous chondrites: step-by-step changes in mineralogy, trace element chemistry, carbonaceous materials, and reflectance spectra have been clarified. Based on data from synchrotron X-ray diffraction analysis of the matrix, heated hydrous carbonaceous chondrites have been classified as Stages I-IV, with the temperature of heating increasing from I to IV. In spite of recent progress, heat sources are poorly defined, mainly due to a lack of chronological information on the timing of the heating, and therefore more data are needed to fully clarify the thermal metamorphism of hydrous carbonaceous chondrites.