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Re-Os同位素定年在石油生成及富有机质沉积岩的绝对定年方面取得了良好的应用效果,并且石油的Os同位素初始值还可以作为油源示踪的指标。分析了Re-Os同位素定年方法在富有机质体系中应用的原理,探讨了影响同位素体系封闭性的各种因素,指出熟化作用、生物降解及水洗作用、脱沥青作用不会影响Re-Os同位素体系的封闭性,而硫酸盐热化学还原作用、成矿流体作用及幔源岩浆混染会扰动Re-Os同位素体系。目前石油系统中Re-Os同位素研究存在的主要问题可归结为2个方面:1石油系统有机质中Re-Os同位素的地球化学行为;2Re-Os同位素年龄的精度及其指示意义。对于这2个方面,开展有机相及现代海藻与Re-Os同位素相关性的研究将有助于了解Re和Os在有机质中的具体富集形式;对控制Re-Os同位素分馏的因素(如沉积环境及有机质类型)的研究将会有助于鉴别哪些地层以及什么样的样品能用来进行Re-Os定年。
The Re-Os isotopic dating has achieved good results in the absolute dating of petroleum-producing and organic-rich sedimentary rocks, and the initial Os isotope values of petroleum can also be used as an indicator of oil source tracing. The principle of Re-Os dating in organic-rich systems was analyzed. Various factors influencing the sealing of isotopic systems were discussed. The effects of aging, biodegradation and water washing were pointed out. The deasphalting did not affect the Re-Os isotope system Of the seal, and sulfate thermochemical reduction, the role of ore-forming fluids and mantle magma contamination will disturb the Re-Os isotope system. At present, the main problems in Re-Os isotope study of petroleum system can be attributed to two aspects: (1) the geochemical behavior of Re-Os isotope in the organic matter of petroleum system; (2) the accuracy of Re-Os isotope age and its significance. For these two aspects, the study of the correlation between Re and Os isotopes of organic and modern seaweeds will help to understand the specific enrichment patterns of Re and Os in organic matter. For the factors that control Re-Os isotopic fractionation, such as sedimentation Environmental and organic types) will help identify which formations and what samples can be used for Re-Os dating.