论文部分内容阅读
深海天然气水合物分解与全球变暖密切相关.南海北部是重要的天然气水合物蕴藏区,ZHS-176、ZHS-174、17940和MD2905孔CaCO3含量记录均表明,11.3~8.0ka B.P.神狐海域存在一次典型的“低钙事件”(CM),该事件具有“快速降低、缓慢升高”不对称的变化结构,CaCO3含量降幅高达9%.“低钙事件”期间,底栖有孔虫Cibicidoides wuellerstorfi和Cibicidoides kullenbergi壳体δ13 C分别负偏了1.4‰和0.7‰,海底有机碳的堆积速率(MAR)也突然升高了1倍.综合分析表明,新仙女木末期南海北部天然气水合物很可能发生了一次较大规模的快速分解,大量甲烷气体从天然气水合物中逸散,氧化后使底层海水快速酸化,从而导致了神狐海域碳酸盐的溶解.底层水团温度上升很可能是神狐海域天然气水合物分解的主要触发因素.
The decomposition of deep-sea natural gas hydrate is closely related to global warming.The northern part of the South China Sea is an important natural gas hydrate reservoir area. The records of CaCO3 content in ZHS-176, ZHS-174, 17940 and MD2905 wells show that 11.3-8.0ka BP A typical “low calcium event” (CM) event with a “rapidly decreasing, slowly rising” asymmetric structure with a CaCO3 content decrease of up to 9%. “During the” low calcium event, "the bottom The δ13C of Cibicidoides wuellerstorfi and Cibicidoides kullenbergi shells negatively deviated by 1.4 ‰ and 0.7 ‰, respectively, and the MAR of seafloor organic carbon suddenly increased by one time.Comprehensive analysis showed that the new fairy woody end in the northern South China Sea Natural gas hydrate is likely to have a large-scale rapid decomposition, a large amount of methane gas escaping from natural gas hydrate, oxidation of the underlying seawater quickly acidification, resulting in Shen Fox waters carbonate dissolution. Rise is likely to be the main trigger for the decomposition of gas hydrates in the Shenhu area.