Aqueous Alteration Mineralogy in CM Carbonaceous Chondrites
Aqueous Alteration Mineralogy in CM Carbonaceous Chondrites
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CM 碳质球粒陨石中的水蚀变矿物学
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
M. Miyamoto
中科院分区：
文献类型：
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作者：
J. Chokai;M. Zolensky;L. Le;Keiko Nakamura;T. Mikouchi;A. Monkawa;E. Koizumi;M. Miyamoto
铁镍硫化物存在于大部分或全部太阳系环境中，可能是目前所有地外物质中唯一发现的矿物。尽管无处不在，但他们并没有得到应有的关注。球粒陨石中最常见的铁镍硫化物是硫铁矿(FeS)、磁黄铁矿(Fe1-XS)和镍黄铁矿(Fe，Ni)9S8。硫铁矿被认为是金属(Fe-Ni)颗粒在含H_2S环境中硫化的结果。磁黄铁矿是当从金属核剥离的脆性硫铁矿颗粒继续硫化时产生的[1]。众所周知，一些小行星经历了水蚀变，形成了包括新一代硫化物(磁黄铁矿和镍黄铁矿)在内的产物。在这种蚀变过程中形成的绿辉石更是众所周知[1]。然而，Lauretta的实验工作表明，在最初的硫化过程中也可能形成了镍黄铁矿[2]，这是因为与铁相比，镍向形成的硫化物中扩散的速度更快。最后，有相当多的证据[1，3和4]证明了介于磁黄铁矿和镍黄铁矿之间的一族相，遵循高温单硫化物固溶体的趋势[5]，这在陆地岩石中是不存在的。
Iron-nickel sulfides are found in most or all solar system environments, and are probably the only minerals found in all extraterrestrial materials on hand. Despite the ubiquity, they have not received the attention they deserve. The most common Fe-Ni sulfides in chondrites are troilite (FeS), pyrrhotite (Fe1- XS) and pentlandite (Fe,Ni)9S8. Troilite is believed to have resulted from sulfidation of metal (Fe-Ni) grains in an H2Scontaining environment. Pyrrhotite is produced when friable troilite grains, which are exfoliated from the metal nucleus, are submitted to continued sulfidation [1]. Some asteroids are known to have experienced aqueous alteration, forming products including new generations of sulfides (pyrrhotite and pentlandite). Pentlandite in particular is known to form during such alteration [1]. However, experimental work by Lauretta has indicated that pentlandite may also have been formed during the initial sulfidation process [2], due to the faster diffusion rate of nickel into the forming sulfide, as compared to iron. Finally, there is considerable evidence [1,3&4] for a family of phases intermediate between pyrrhotite and pentlandite, following the trend of the high temperature monosulfide solid solution [5], something not encountered in terrestrial rocks.