黄鑫,李隆威,王汶卓,等. 冲绳海槽唐印和第四与那国热液区热液产物中烷烃组成和来源[J]. 海洋地质与第四纪地质,2023,43(5): 181-189. DOI: 10.16562/j.cnki.0256-1492.2023091401
引用本文: 黄鑫,李隆威,王汶卓,等. 冲绳海槽唐印和第四与那国热液区热液产物中烷烃组成和来源[J]. 海洋地质与第四纪地质,2023,43(5): 181-189. DOI: 10.16562/j.cnki.0256-1492.2023091401
HUANG Xin,LI Longwei,WANG Wenzhuo,et al. The composition and source of hydrocarbons in the hydrothermal products of Tangyin and Yonaguni Knoll IV hydrothermal fields from the Okinawa Trough[J]. Marine Geology & Quaternary Geology,2023,43(5):181-189. DOI: 10.16562/j.cnki.0256-1492.2023091401
Citation: HUANG Xin,LI Longwei,WANG Wenzhuo,et al. The composition and source of hydrocarbons in the hydrothermal products of Tangyin and Yonaguni Knoll IV hydrothermal fields from the Okinawa Trough[J]. Marine Geology & Quaternary Geology,2023,43(5):181-189. DOI: 10.16562/j.cnki.0256-1492.2023091401

冲绳海槽唐印和第四与那国热液区热液产物中烷烃组成和来源

The composition and source of hydrocarbons in the hydrothermal products of Tangyin and Yonaguni Knoll IV hydrothermal fields from the Okinawa Trough

  • 摘要: 通过气相色谱-质谱联用仪(GC-MS)和气相色谱-同位素质谱仪(GC-IRMS),分别分析了冲绳海槽南部唐印和第四与那国热液区热液硫化物与热液沉积物中烷烃含量和正烷烃单体碳同位素组成特征。热液产物样品中正烷烃显示出明显的双峰分布,高分子正烷烃显示出明显的奇数碳优势,其丰度最大值位于C31处;低分子正烷烃显示出偶数碳优势,其丰度最大值位于C18处。正烷烃的分布特征以及正烷烃碳同位素组成表明,样品中正烷烃主要来源于热液微生物代谢活动和陆源高等植物的输入,其中,低分子的正烷烃主要来源于热液微生物代谢活动,而高分子的正烷烃主要来源于陆源高等植物。热液硫化物样品中低分子正烷烃含量和比重都高于热液沉积物,表明热液硫化物中热液微生物活动可能更加繁盛。热液硫化物中正烷烃单体的δ13C表现出随碳原子个数增加,同位素值减小的趋势,暗示该区非生物合成有机质的贡献可能不能忽略。

     

    Abstract: The hydrothermal sulfide and sediment of the Tangyin and Yonaguni Knoll Ⅳ hydrothermal fields in the southern Okinawa Trough were analyzed in gas chromatography-mass spectrometry (GC-MS) and gas chromatography-isotope ratio mass spectrometry (GC-IRMS), by which the abundances of hydrocarbons and the individual C isotope compositions of n-alkane were determined. The n-alkanes in the hydrothermal products conformed to a bimodal distribution, and exhibited an odd-to-even predominance of high molecular weight n-alkanes with maxima at C31 and an even-to-odd predominance of low molecular weight n-alkanes with maxima at C18. The distribution and individual carbon isotopic compositions of n-alkanes suggest that the low molecular weight n-alkanes in hydrothermal products may be mainly the result of the metabolic activity of submarine hydrothermal microorganisms, and the high-molecular weight n-alkanes in hydrothermal products may be derived from mainly the terrigenous inputs. The content and proportion of low-molecular n-alkanes in hydrothermal sulfides are higher than those of hydrothermal sediment, indicating that hydrothermal microbial activity might be more flourishing in hydrothermal sulfide. The δ13C values of the n-alkanes in the hydrothermal sulfide samples tend to decrease as the number of carbon atoms increased, which suggest that the abiogenic contribution to the source of hydrocarbons in hydrothermal sulfides shall not be ignored.

     

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