摘要
新元古代末期,地球至少经历了两次全球性的冰川作用,研究者提出了“雪球”假说来解释新元古代时期一系列特殊的地质现象,该假说已成为研究新元古代全球冰川作用和其后生物大爆发事件的窗口。但一些学者并不赞成地球曾经是被冰雪完全覆盖的“雪球”,并分别提出了“半融雪球/无冰水体”和“薄冰”假说。尽管每一种假说都不能解释所有的地质、地球化学现象,但越来越越多的证据,特别是分子有机地球化学和古生物学的证据表明,“雪球”时期的海洋并没有完全被冰封盖,在赤道地区的冰盖可能很薄或存在无冰的水体。无冰水体的存在可以使一些光合生物继续生存和演化,这对其后的“寒武纪生物大爆发”事件和生命演化具有重要的意义。
During the Neoproterozoic, earth suffered through at least two globe-engulfing ice age. Researchers proposed ＂Snowball earth＂ hypothesis to explain a series of puzzling Neoproterozoic sedimentary recordings. This hypothesis has become an ancient widow for the study of global glaciation and bio-radiation aftermath. Other researchers, however, do not agree that the earth has been completely ice-covered. They proposed alternative hypotheses, such as ＂Slushball/Semifrozen Earth＂, and ＂Thin-ice＂ models. Although, each hypothesis cannot explain all the geological and geochemical recordings, more and more evidence, especially, molecular organic geochemical and biological evi- dences show that the ocean was not entirely ice-covered during ＂Snowball Earth＂ age. Thin ice sheets or open water zones remained in tropical areas. The open water zone is essential for the survival and evolution of photosynthetic organisms, which would make a significant impact on the ＂Cambrian Bio-radiation＂ and the evolution of life on the earth.
出处
《沉积学报》
CAS
CSCD
北大核心
2006年第1期107-112,共6页
Acta Sedimentologica Sinica
基金
国家自然科学基金项目"扬子区寒武纪生物大爆发事件分子有机地球化学研究"(批准号:40172049)资助
关键词
新元古代
雪球
寒武纪生物大爆发
光合生物
无冰水体
Neoproterozoic, ＂Snowball Earth＂, Cambrian Bio-radiation, photosynthetics organism, open water
