| 南方海相上奥陶统—下志留统优质烃源岩 发育的控制因素 |
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| 引用本文： | 李双建,肖开华,沃玉进,龙胜祥,蔡立国.南方海相上奥陶统—下志留统优质烃源岩 发育的控制因素[J].沉积学报,2008,26(5):872-880. |
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| 作者姓名： | 李双建 肖开华 沃玉进 龙胜祥 蔡立国 |
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| 作者单位： | 中国石油化工股份有限公司石油勘探开发研究院 北京 100083 |
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| 基金项目： | 国家重点基础研究发展计划(973计划) |
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| 摘 要： | 从全球古气候和古海洋特征出发，结合中国南方晚古生代古地理演化特征，并利用中上扬子地区典型剖面系统的地球化学数据，探讨了南方海相上奥陶统—下志留统优质烃源岩发育的控制因素。研究表明V/（V+Ni）、Ni/Co、Ceanom、δEu和δ13Corg等地球化学指标与有机碳含量均有较好的相关性，这些指标的异常匀表明上奥陶统—下志留统优质烃源岩发育于缺氧环境。但是，从古气候和古海洋洋流的研究结果看，上奥陶统五峰组烃源岩与下志留统龙马溪组烃源岩的发育因素有明显的不同，五峰组沉积处于全球冰期的高峰阶段，在扬子地区发育强劲的上升洋流，提高了该地区的有机质的生产率，现今广泛分布在扬子地区的高有机质丰度的薄层硅质岩，是上升洋流的最好标志。龙马溪组沉积处于全球冰期过后的暖期，不利于上升洋流的大规模形成，上升洋流的影响范围仅局限于当时扬子克拉通盆地周缘深水斜坡部位。龙马溪组优质烃源岩主要发育在海侵的初期，主要是因为海侵初期海平面的快速上升，限制了陆源碎屑的大规模注入，海底的缺氧环境得以保存。而海侵的后期由于深层海水和表层海水有充足的时间混合，致使底部缺氧环境遭受破坏，有机质保存条件变差。
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| 关 键 词： | 南方 海相 烃源岩 上奥陶统—下志留统 地球化学 上升洋流 |
| 收稿时间： | 1900-01-01 |
Developmental Controlling Factors of Upper Ordovician-Lower Silurian High Quality Source Rocks in Marine Sequence, South China |
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| LI Shuang-jian,XIAO Kai-hua,WO Yu-jin,LONG Sheng-xiang,CAI Li-guo.Developmental Controlling Factors of Upper Ordovician-Lower Silurian High Quality Source Rocks in Marine Sequence, South China[J].Acta Sedimentologica Sinica,2008,26(5):872-880. |
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| Authors: | LI Shuang-jian XIAO Kai-hua WO Yu-jin LONG Sheng-xiang CAI Li-guo |
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| Institution: | Exploration & Development Research Institute, SINOPEC, Beijing 100083 |
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| Abstract: | From the angel of paleo climate and paleo oceangraphy, combined with Paleozoic paleo geography characters, the developmental controlling factors of Upper Ordovician Lower Silurian high quality source rocks in marine sequence, South China were discussed in this paper, with analysis of geochemical data in typical section from upper Yangtze. The researches indicate geochemical indicators such as V/（V+Ni）, Ni/Co, Ceanom, δEu and δ13Corg have good relationship with the content of organic carbon, and the abnormal of these indicators illustrate that the high quality source rocks of Upper Ordovician Lower Silurian were developed in anoxic environment. However, from the researches of paleo climate and paleo oceangraphy, the developmental controlling factors of Wufeng Formation in Upper Ordovician are different with those of Longmaxi Formation in Lower Silurian. As the ice age reached its crest in Wufeng period, the intense upper welling formed in Yangtze area, which improved the organic production. The thin argillite with high abundance of organic matter covered in Yangtze area are the best indicators of upper welling. The global paleo climate came into a warm period as Longmaxi Formation deposit, which were disadvantage for lager scale upper welling. In this period, the effects of upper welling were limited in deep slope around Yangtze craton. High quality source rocks of Longmaxi Formation were developed in early period of transgression. Because during initial transgression, coarser grained siliciclastics are constrained to fill, and the anoxic environment were preserved. During latter transgression, as the deep water and surface water have abundance time to mix, the anoxic environment were destroyed in deep sea, as a result of which, the preservation condition of organic matter become bad. |
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| Keywords: | South China marine source rock Upper Ordovician-Lower Silurian geochemistry upper welling |
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