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对中太平洋莱恩海山富钴结壳MP5D17的各壳层样品进行了系统的锇同位素组成测定.研究表明,结壳中187Os/188Os比值变化较大,变化范围在0.4262～1.0155之间.从底部到顶部,结壳剖面中锇同位素组成呈有规律的变化趋势,并与结壳的垂直剖面结构构造的变化相关联.对比研究表明,结壳MP5D17剖面的锇同位素组成曲线,具有与80Ma以来海水锇同位素演化曲线相似的演化趋势.初步推测富钴结壳MP5D17的生长起始时间为72Ma,该结壳的生长过程中存在三次生长间断,其时间分别为64,53和37Ma.
The Os isotopic compositions of various crusts from the crust-bearing cobalt crust MP5D17 in the central Rhine Seashore of the Pacific Ocean were systematically studied.The results showed that the ratios of 187Os / 188Os in crusts varied greatly from 0.4262 to 1.0155, The composition of the osmium isotopes in the top and crust profiles showed a regular trend and was correlated with the changes of the crustal structure in the vertical section.Comparative studies showed that the osmium isotope composition curve of the crust MP5D17 section was similar to that of the seawater osmium Isotopic evolution curve.The evolution of MP5D17 was presumed to be 72Ma. There were three growth discontinuities in the crust, with the time of 64, 53 and 37Ma, respectively.