| 桂中晚二叠世碳酸盐岩碳同位素的地层学意义 |
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| 引用本文： | 邵龙义,Jones T P.桂中晚二叠世碳酸盐岩碳同位素的地层学意义[J].沉积学报,1999,17(1):84-120. |
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| 作者姓名： | 邵龙义 Jones T P |
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| 作者单位： | 1.中国矿业大学北京校区,北京 100083; |
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| 摘 要： | 广西合山马滩等地的上二叠统剖面碳酸盐岩碳同位素在吴家坪阶和长兴阶界线处表现出明显的降低现象，吴家坪阶石灰岩样品δ１３Ｃ值一般都高于３．２‰，而长兴阶的样品其δ１３Ｃ值多低于３．２‰，因此，碳同位素组成的差异有可能作为吴家坪阶和长兴阶的同位素地层界线。这种同位素降低现象可能与澳洲、南非、印度等地大规模聚煤作用的中止有关。聚煤作用的中止以及以前埋藏的泥炭和煤层在遭受构造抬升和氧化后会向大气中释放出大量富含轻同位素１２Ｃ的ＣＯ２，从而使得与大气平衡的海水及在其中沉淀出的碳酸盐岩的δ１３Ｃ值降低。
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| 关 键 词： | 碳同位素 晚二叠世 聚煤间断 |
| 收稿时间： | 1997-11-18 |
Carbon Isotopes and the Stratigraphical Implication of the Late Permian Carbonates in Central Guangxi |
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| Shao Longyi,Jones T P.Carbon Isotopes and the Stratigraphical Implication of the Late Permian Carbonates in Central Guangxi[J].Acta Sedimentologica Sinica,1999,17(1):84-120. |
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| Authors: | Shao Longyi Jones T P |
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| Institution: | 1.China University of Mining and Technology,Beijing 100083;Department of Earth Sciences,Cardiff University, Cardiff,CFI 3YE,UK |
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| Abstract: | The carbon isotope compositions of the Late Permian carbonate rocks in central Guangxi show a sharp decrease at the boundary between Wujiapingian and Changxingian(W/C) stages.The limestone samples of the Wujiapingian stage have the δ13C values higher than 3.2‰,whereas the Changingian samples have the δ13C values lower than 3.2‰.This negative shift is suggested to be used to distingush the Wujiapingian and Changxingian stages.The carbon isotope depletion at the W/C boundary is believed to be related to the termination of the coal accumulation in large areas such as the India,eastern Australia,and South Africa but not southern China.The cessation of the coal accumulation and the oxidation of the previously buried coals as a result of the tectonic uplift may release12C rich CO2 into the atmosphere which further leads to the decrease of the δ13C values in ocean water and the marine carbonate rocks. |
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