摘要
新元古代在全球范围内出现了几期冰期事件,称之为“雪球地球”事件。这种剧烈的环境变化带来此后地球上生命演化的一次飞跃。“雪球地球”事件的核心是全球冰期的同时性,需要同位素地质年代学的证据。新元古代末期两次主要的冰期事件是Marinoan冰期和Sturtian冰期,其中Marinoan冰期结束于635Ma;Sturtian冰期可能发生在710～720Ma,已发表的年龄数据限定它在670Ma之前结束。Marinoan冰期后的Gaskiers冰期发生在580～590Ma。对华南的古城、铁丝坳、长安组、江口组等进行进一步精确定年,将对限定Sturtian冰期持续时间和Cryogenian、南华系的下限年龄具有重要意义。
There were several glacial events around the world which are called “Snowball Earth” during the late Neoproterozoic time. These glaciations profoundly influenced early faunal evolution. “Snowball Earth” is at the core of the glaciations events, therefore we need precise geochronological data in order to prove the global synchroneity of the Neoproterozoic glaciations. Two major Neoproterozoic glaciations are Marinoan and Sturtian. A number of studies suggested that the Marinoan glaciation terminated about 63...
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2007年第2期249-256,共8页
Earth Science Frontiers
基金
国家自然科学基金项目(40532012
40373011)
中国科学院知识创新工程项目(KZCX3-SW-141)
