Molybdenum Isotope Signatures from Yangtze Craton Continental Margin and Its Indication to Organic Burial Rate
Molybdenum Isotope Signatures from Yangtze Craton Continental Margin and Its Indication to Organic Burial Rate
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发表时间：
2007
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通讯作者：
W. Feng
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作者：
W. Feng
本文利用钼同位素资料，结合微量元素含量，探讨了扬子克拉通大陆边缘沉积物中自生钼在长期埋藏过程中的地球化学行为及其对原始有机碳埋藏的指示作用。原始有机碳的埋藏速率是根据沉积硫含量（TS含量）估算的，而好氧降解的碳损失是根据计算的Mn含量估算的。在这些点上计算了原始有机碳通量，显示出较大的变化范围（0.17-0.67 mmol/m2/day）。本文还利用前人在现代海洋沉积物调查基础上提出的沉积Mo同位素值与有机碳埋藏速率之间的强相关性来估算有机碳埋藏速率。通过该模型获得的数据表明，有机碳埋藏速率变化较大，范围为0.43 ~ 2.87 mmol/m2/day。虽然扬子克拉通不同地球化学记录的两组数据存在一个数量级的偏差，但它们确实显示出很强的相关性。因此，可以推测沉积物的Mo同位素特征可以作为大陆边缘沉积物中原始有机碳积累速率的示踪剂。
The paper presents the molybdenum isotope data, along with the trace element content, to investigate the geochemical behavior of authigenic Mo during long-term burial in sediments in continental margin settings of Yangtze craton, as well as their indication to the burial of original organic carbon. The burial rate of original organic carbon was estimated on the basis of the amount of sedimentary sulphur (TS content), whilst the carbon loss by aerobic degradation was estimated according to calculated Mn contents. On these points, the original organic carbon flux was calculated, exhibiting a large range of variation (0.17-0.67 mmol/m2/day). The strong correlation between sedimentary Mo isotope values and organic carbon burial rates previously proposed on the basis of the investigations on modern ocean sediments, was also used here to estimate the organic carbon burial rate. The data gained through this model showed that organic carbon burial rates have large variations, ranging from 0.43-2.87 mmol/m2/day. Although the two sets of data gained through different geochemical records in the Yangtze craton show a deviation of one order of magnitude, they do display a strong correlation. It is thus tempting to speculate that the Mo isotope signature of sediments may serve as a tracer for the accumulation rate of original organic carbon in the continental margin sediments.