【摘要】 简要介绍了由美国一些科学家最近提出的 ,引起国际地球科学、环境科学、生命科学及宇宙科学界广泛关注的新元古代雪球假说 (theSnowballEarthHypothesis) ,及其近期研究情况。根据我国扬子地层分区和江南地层分区震旦系的沉积特征 ,对新元古代古气候骤变 ,大冰期的发生与消亡及其诱发因素作了初步探讨。更多还原

【Abstract】 Joseph L. Kirsch vink(1992) applied the hypothesis of a s nowball Earth to explain the low-paleola titude glacial deposits as well as the o ccurrence of banded iron formations, sug gesting that an ocean sealed by sea ice would quickly become anoxic and rich in dissolved ferrous iron. Paul F. Hoffman, et al.(1998) presented new data on the amplitude, timing, and duration of inorg anic δ 13 C variations in Neoproterozoi c rocks of northern Namibia and the rela tion between these variations and glacia tions. They show that the snowball Earth hypothesis could explains the geologica l and geochemical observations, includin g the δ 13 C excursion and the existenc e of cap carbonates immediately deposite d overlying the glaciations. In China, late Neoproterozoice(Sinian) s equence is widely developed in the Yangt ze Plateform. It includes(in asending or der) Liantuo, Nantuo, Doushantuo and Den gying formations. The data of lithologic al and geochemistry from the Sinian sequ ence also smoothly support that hypothes is. The triggers of late Neoproterozoic glaciations might possibly involve exten sive consumption of carbon dioxide in at mosphere, continents gathered around the Equator and reduction of warmth receive d from the Sun etc.更多还原