| 摘要: |
| 本研究采用色谱质谱(GC-MS)和色谱-同位素质谱(GC-IRMS)方法, 对珠江口盆地Site4B沉积物中脂肪醇分子化合物分布以及单体碳同位素组成进行了研究。结果表明: 长链脂肪醇碳优势指数(CPIC26-34: 9.41 - 24.56)、平均碳链长度(ACLC26-34: 28.85 - 29.99)以及nC26 - nC30脂肪醇平均碳同位素组成(?29.13‰±0.87‰、?32.98‰±1.28‰和?32.73‰±1.61‰)均揭示了nC26 - nC34脂肪醇属于陆源高等植物来源, nC16 - nC20和nC24脂肪醇较正的碳同位素组成反映了化合物的海洋细菌来源, 而nC22脂肪醇偏负的碳同位素特征(平均?33.26‰±1.51‰)反映了化学自养细菌来源。Site4B沉积物中的陆源输入主要来自南海周边河流, 从12.7ka BP至今的沉积时期(0 - 80cm, 文中深度均为埋深)和末次冰盛期(102 - 120cm), 其陆源输入主要来自台湾岛河流, 而在19.3 - 12.7ka BP沉积时期(80 - 102cm)和更新世沉积时期(120 - 300cm), 台湾岛、吕宋岛和珠江口河流的陆源贡献普遍较低。Site4B沉积物中的海洋生产力主要来自海洋微生物输入的贡献, 并主要受到海水温差影响; 其中在35 - 150cm层位, 海洋输入和南海暖流的强弱带来的海水温度的高低有关, 而在150 - 300cm层位, 则主要和冰期-间冰期的冷暖气候带来的海水温差有关。 |
| 关键词: 珠江口盆地 脂肪醇 碳同位素 陆源输入 海洋生产力 |
| DOI：10.11693/hyhz20131200219 |
| 分类号: |
| 基金项目:国家自然科学基金, 41303067 号, 41103043 号; 中国科学院广州能源研究所所长基金, y107r71001 号; 有机地球化学国家重点实验室开放基金, OGL-201209 号 |
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| MOLECULE DISTRIBUTION OF ALCOHOL COMPOUNDS IN SITE4B CORE SEDIMENTS FROM THE ZHUJIANG (PEARL) RIVER MOUTH BASIN AND ITS IMPLICATION |
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zhuxiaowei,maoshengyi,sunyongge,guanhongxiang and wunengyou
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Guangzhou Institute of Geochemistry,Guangzhou Institute of Energy Conversion,Zhejiang University,Guangzhou Institute of Energy Conversion,Guangzhou Institute of Energy Conversion
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| Abstract: |
| Distribution and carbon isotope composition of alcohol compounds in Site4B sediment in the Zhujiang (Pearl) River Mouth Basin are analyzed by GC-MS (gas chromatography-mass spectrometry) and GC-IRMS (gas chromatography-isotope ratio monitoring mass spectrometry). The results show that the values of carbon preference index (9.41 - 24.56), average chain length (28.85 - 29.99), and the average carbon isotope of nC26, nC28, and nC30 aliphatic alcohol (?29.13‰±0.87‰, ?32.98‰±1.28‰, and ?32.73‰±1.61‰, respectively) indicate a source of terrestrial higher plants for nC26 - nC34 aliphatic alcohols. The carbon isotope compositions of nC16 - nC20 and nC24 aliphatic alcohols were substantially enriched in 13C relative to nC26 - nC34 aliphatic alcohols, suggesting potential source of marine microbe other than terrestrial higher plants; the negative isotope composition of nC22 aliphatic alcohol (?33.26‰±1.51‰) might indicate a potential source of the chemical autotrophic bacteria. The terrigenous inputs in the sediments are dominated by adjacent rivers. Contribution of the Taiwan Island rivers was significant since 12.7ka BP (0 - 80cm) and in the Last Glacial Maximum (102 - 120cm), whereas those of the Taiwan Island, Luzon Arc, and Zhujiang River estuary rivers were generally not significant from 19.3 - 12.7ka BP (80 - 102cm) and in the Pleistocene (120 - 300cm). The marine productivity was contributed by marine microbe that effected heavily by fluctuation in seawater temperature, of which at depths of 35 - 150cm marine-sourced alcohols was related to the seawater temperature fluctuation caused by the change in the strength of the South China Sea warm current, whereas at depths of 150 - 300cm, it was directly related to the seawater temperature variation resulted from cold-warm climate alternation between glacial and interglacial periods. |
| Key words: Zhujiang (Pearl) River Mouth Basin alcohol compound carbon isotope terrigenous input marine productivity |
