【作者】 张同钢； 储雪蕾； 冯连君； 张启锐； 郭建平；

【Author】 Zhang Tonggang ChuXuelei Feng Lianjun Zhang Qirui(Institute of Geology and Geophysics, Key Lab of Mineral resources Exploration and Research, Chinese Academy of Sciences, Beijing 100029,China;China University of Geosciences(Beijing), Beijing, 100083)

【机构】 中国科学院地质与地球物理所； 中国地质大学(北京)；

【摘要】 在新元古代晚期地球上曾发生过全球性的冰川作用,一些学者称之为“雪球”事件。在新元古代雪球事件前后,古海水的碳和硫同位素组成都出现了非常大的变化,在雪球之前海水中的碳酸盐非常富集¹³C,在雪球期间和紧随雪球之后贫¹³C,然后δ¹³C值出现了高达10‰的正漂移;在雪球开始之前古海水硫酸盐的δ³⁴S值呈逐渐降低的变化特征,紧随雪球之后古海水硫酸盐的δ¹³S值出现了超过20‰的正漂移,达到地质史上的最高值,同期形成的硫化物具有异常高的δ³⁴S值。“雪球”事件前后古海水碳和硫同位素组成的大幅度变化,是由雪球前后全球环境的剧烈变化引起的。雪球前后海水碳和硫同位素的大幅度变化是与雪球有关的特殊环境条件作用的结果,也是雪球事件存在的有力证据。更多还原

【Abstract】 There were global glaciations that took place on the Earth in Neoproterozoic called as the "Snowball Earth" event by some scholars. Seawater carbon and sulfur isotopic compositions occurred large-amplititude variations near the Snowball Earth event. The carbonate in seawater very enriched in 13C before the snowball Earth and depleted 13C during and after the snowball Earth event. Then, δ34S values of carbonates occurred a large positive drift reached +10‰. The δ34S value of seawater sulfate became lower gradually before the Snowball Earth event. There was large positive drift of δ34S value which exceeded +20‰ and reached the climax as soon as the snowball Earth was over. The synchronous sulfides had ultra-high δ34S values. These large-amplititude variations of seawater’s carbon and sulfur isotopic compositions were caused by sharp change of the environment near the snowball Earth. These variations of seawater carbon and sulfur isotope were the result of the effect of the snowball Earth, at the same time they can be regarded as proofs of the existing of the snowball Earth event.更多还原