Comparing Wild 2 particles to chondrites and IDPs
Comparing Wild 2 particles to chondrites and IDPs
复制标题
DOI：
10.1111/j.1945-5100.2008.tb00621.x
复制
发表时间：
2008-01-01
影响因子：
2.2
通讯作者：
Bridges, John
中科院分区：
文献类型：
--
作者：
Zolensky, Michael;Nakamura-Messenger, Keiko;Bridges, John
我们比较了观察到的橄榄石，辉石，铁镍硫化物在野生2颗粒与那些从南极行星际尘埃颗粒（IDPs）和球粒陨石类的组成范围，以探讨这些数据是否表明亲和力，特别是已知的含水材料。Wild 2橄榄石的组成范围非常宽，从Fa（0-96），在Fa（1）处有一个明显的频率峰。低钙辉石的成分范围也很广，从Fs（48）到Fs（0），在Fs（5）处有一个显著的频率峰。这些范围与所报道的任何其他地外物质的范围一样宽或更宽。Wild 2 Fe-Ni硫化物主要具有接近FeS的成分，Ni小于2原子%;迄今为止，在Wild颗粒中仅发现了两个镍黄铁矿颗粒，表明这种矿物并不丰富。FeS和镍黄铁矿之间完全没有组成（具有中间固溶体组成）表明（但不要求）FeS和镍黄铁矿作为结晶物质凝聚，即，没有形成后来退火的非晶相。虽然我们尚未观察到任何含水矿物的直接证据，但含镍硫化物和镁为主的橄榄石和低钙辉石的存在并不排除它们以低丰度存在。我们的结论是，新的调查的主要和次要元素组成的球粒陨石矩阵和国内流离失所者是必要的。
We compare the observed composition ranges of olivine, pyroxene, and Fe-Ni sulfides in Wild 2 grains with those from chondritic interplanetary dust particles (IDPs) and chondrite classes to explore whether these data suggest affinities to known hydrous materials in particular. Wild 2 olivine has an extremely wide composition range, from Fa(0-96), with a pronounced frequency peak at Fa(1). The composition range displayed by the low-calcium pyroxene is also very extensive, from Fs(48) to Fs(0), with a significant frequency peak centered at Fs(5). These ranges are as broad or broader than those reported for any other extraterrestrial material. Wild 2 Fe-Ni sulfides mainly have compositions close to that of FeS, with less than 2 atom% Ni; to date, only two pentlandite grains have been found among the Wild grains, suggesting that this mineral is not abundant. The complete lack of compositions between FeS and pentlandite (with intermediate solid solution compositions) suggests (but does not require) that FeS and pentlandite condensed as crystalline species, i.e., did not form as amorphous phases, which later became annealed. While we have not yet observed any direct evidence of water-bearing minerals, the presence of Ni-bearing sulfides, and magnesium-dominated olivine and low-Ca pyroxene does not rule out their presence at low abundance. We do conclude that new investigations of major- and minor-element compositions of chondrite matrix and IDPs are required.