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利用从碳酸盐岩中提取微量硫酸盐的方法,实现了扬子地区陡山沱组海相碳酸盐岩地层连续的硫和碳同位素组成测定.未受成岩作用改造的同一样品的硫和碳同位素分析结果能够同时给出扬子地区陡山沱期古海水的硫和碳同位素组成.获得的高分辨率陡山沱期硫酸盐的硫同位素年代曲线可能反映了“雪球地球”事件之后全球古海洋的硫同位素变化趋势,它与同时期的碳同位素年代曲线变化相似.陡山沱期早期古海水的δ34S值出现超过20‰的正漂移,同期δ13C值也出现高达10‰的正漂移,使古海水的δ34S值和δ13C值分别达到+46.4‰和+6.9‰的高值.在陡山沱期中期古海水的δ34S值的变化幅度相对较小,对应于较高的δ13C值.随后,古海水的δ34S值呈现较强烈的振荡,δ13C值也有类似表现.在陡山沱期末期海水的硫和碳同位素都出现了大幅度的负漂移,δ值分别降到-10.1‰和-5.7‰.扬子地区陡山沱期古海水的硫和碳同位素组成与变化意味着南沱冰期之后的海洋环境发生了急剧变化,环境十分有利于生物繁衍与活动,那时的生物产率和有机碳埋藏速率曾达到很高的水平.不过,“雪球地球”之后的环境并不稳定,全球的气候与环境可能都曾发生过波动与反复.发生在陡山沱末期海水的硫和碳同位素的负漂移是一次全球性事件,可能与深部海水氧化有关.
Using the method of extracting trace sulphate from carbonate rocks, the continuous determination of sulfur and carbon isotopic compositions of the Doushantuo marine carbonate rocks in the Yangtze area has been achieved.The sulfur and carbon of the same samples not altered by diagenesis The results of isotope analysis can simultaneously give the sulfur and carbon isotopic composition of the ancient Doushantuo water in the Yangtze area.The sulfur isotopic dating of the high-resolution Doushantuo-karst sulphate may reflect the global paleo- Which is similar to that of the contemporaneous carbon isotope dating.The δ34S values of the early paleo-seawaters in the Doushantuo period show a positive drift of more than 20 ‰ while the δ13C values also show positive drift of up to 10 ‰ in the same period The δ34S values and δ13C values of paleo-sea water reach the high values of +46.4 ‰ and + 6.9 ‰, respectively.The variation of δ34S values of paleo-seawater in the middle Doushantuo period is relatively small, corresponding to the higher δ13C value, The δ34S value of seawater shows a strong oscillation, and the δ13C value is also similar. At the end of the Doushantuo period, the sulfur and carbon isotopes of seawater show a large negative drift, and their δ values drop to -10.1 ‰ and -5.7 ‰, respectively. Yang The sulfur and carbon isotopic compositions and changes of ancient seawater in the Doushantuo period in the sub-region mean that the marine environment after the Nantau glaciation has undergone dramatic changes and the environment is very conducive to the reproduction and activity of the organisms. At that time, the bio-productivity and the burial rate of organic carbon Has reached a very high level.However, “Snowball Earth” after the environment is not stable, the global climate and environment may have experienced fluctuations and iterations.Stage occurred at the end of the Doushantuo sulfur and carbon isotopes of the negative drift It is a global event that may be related to the oxidation of deep seawater.