南黄海柱状沉积物中烃类化合物的地球化学特征及其对沉积环境的指示
摘要: 重点探讨了南黄海柱状沉积物中烃类化合物的分子组成特征及其对沉积环境的指示意义，结果显示，沉积柱中总有机碳（TOC）和总氮（TN）具有较好的正相关性，无机氮的影响较弱，这可能跟本区受径流输入的陆源物质的影响较弱有关。上层样品（0～10 cm）中长链正构烷烃占优势，奇偶优势显著，反映了陆源高等植物贡献；藿烷、甾烷的组成则显示该段样品中有机质具有较高的热成熟度；且姥鲛烷（Pr）/植烷（Ph）比值大于1.0，指示沉积环境以氧化为主，这相对不利于海洋源有机质的保存，从而凸显了陆源有机质的贡献。在10～20 cm之间，沉积环境由相对偏氧化向偏还原过渡；20 cm以下表现为强还原性的沉积环境，有机质成熟度较低。中、下层样品中正构烷烃多呈现双峰分布，短链烷烃具有一定的偶奇优势，这可能主要跟海洋浮游生物、藻类及微生物的贡献有关。与渤海烃类化合物的沉积记录进行对比，发现渤海沉积柱中烃类化合物主要跟历史时期不同来源物质的输入及人类活动的影响有关，而南黄海沉积柱中烃类化合物的特征则主要反映了沉积环境和微生物作用对有机质的埋藏保存有重要影响。
Geochemical Characteristics of Hydrocarbons in the Core Sediments from the South Yellow Sea and Its Implication for the Sedimentary Environment
Abstract: The vertical variation, composition and sources of sedimentary organic matter and aliphatic hydrocarbons of the core sediments from the south Yellow Sea were exactly evaluated and characterized in terms of the molecular composition of the hydrocarbon compounds and its implication for the sedimentary environment. The results show that there exited a good positive correlation between the total organic carbon and total nitrogen, while the occurrence inorganic nitrogen and its potential influence on the SOM identification is poor, which could be related with the low riverine input of the terrigenous materials in the study area. The long chain nalkanes show a high abundance in the 0～10 cm section with eventoodd predominance of the C2535 nalkanes and a higher Pr/Ph ratio (>1.0), indicating a relatively oxidative sedimentary environment. This condition is unfavorable for the preservation of marine organic matter, and in turn, exhibiting a more contribution from the terrigenous organic matter at this interval, while the compositional patterns of hopanes and steranes suggested the presence of a more mature constituents in the upper sections. The sedimentary setting exchanged from the oxidative condition to the anoxic ones with the increasing depth at the 10～20 cm section. Below the 20 cm layer, the sedimentary environment is more characterized of anoxic condition with a low maturation of the buried organic matter. The alkanes in those downsections showed a bimodal with the even carbon preference of the C1222 nalkanes, which could be derived from marine bacteria, fungi and yeast species. By comparing with the sedimentary records in Bohai Sea which were more related to the variation of the historical fluvial input and human actions, while for the Yellow Sea, the molecular compositional patterns of the typical hydrocarbon compounds indicate the important role of the sedimentary condition and microbial biodegradation for the burial and preservation of organic matter in the core sediments.
南黄海柱状沉积物中烃类化合物的地球化学特征及其对沉积环境的指示[J]. 沉积学报, 2013, 31(1): 108-119.
| 引用本文: |
南黄海柱状沉积物中烃类化合物的地球化学特征及其对沉积环境的指示[J]. 沉积学报, 2013, 31(1): 108-119.
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Geochemical Characteristics of Hydrocarbons in the Core Sediments from the South Yellow Sea and Its Implication for the Sedimentary Environment[J]. Acta Sedimentologica Sinica, 2013, 31(1): 108-119.
| Citation: |
Geochemical Characteristics of Hydrocarbons in the Core Sediments from the South Yellow Sea and Its Implication for the Sedimentary Environment[J]. Acta Sedimentologica Sinica, 2013, 31(1): 108-119.
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