Organic Carbon Aging During Across-Shelf Transport
Organic Carbon Aging During Across-Shelf Transport
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DOI：
10.1029/2018gl078904
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发表时间：
2018-08-28
影响因子：
5.2
通讯作者：
Eglinton, Timothy I.
中科院分区：
文献类型：
--
作者：
Bao, Rui;Uchida, Masao;Eglinton, Timothy I.
对不同粒度的表层沉积物进行了化合物特有的放射性碳分析，以检测和比较有机碳的横向迁移时间(LTTS)。长链叶蜡脂肪酸沿相邻大陆边缘河流衍生物质的两条扩散路径老化的C-14表明，LTT的距离类似于30至500公里，从数百年到数千年不等。不同粒级的老化程度不同。我们的发现表明，LTT在时间和空间上都随着不同大陆架环境的特定性质而变化。观察表明，C-14的老化在大陆架的横向运输过程中普遍存在，流体动力颗粒分选导致不同粒度的有机组分之间存在年龄差异。考虑这些现象对于理解碳循环过程和解释大陆边缘沉积记录具有重要意义。
Compound-specific radiocarbon analysis was performed on different grain-size fractions of surficial sediments to examine and compare lateral transport times (LTTs) of organic carbon. C-14 aging of long-chain leaf wax fatty acids along two dispersal pathways of fluvially derived material on adjacent continental margins implies LTTs over distances of similar to 30 to 500km that range from hundreds to thousands of years. The magnitude of aging differs among grain size fractions. Our finding suggests that LTTs vary both temporally and spatially as a function of the specific properties of different continental shelf settings. Observations suggest that C-14 aging is widespread during lateral transport over continental shelves, with hydrodynamic particle sorting inducing age variations among organic components residing in different grain sizes. Consideration of these phenomena is of importance for understanding carbon cycle processes and interpretation on sedimentary records on continental margins.