关于建立“板溪系”的建议及其基础的讨论--以黔东地区为例  

A Proposal to Establish the Banxi System and Discussion on Its Foundations——Based Mainly on Studies in Eastern Guizhou Area

作　　者：汪正江[1] 

机构地区：[1]国土资源部成都地质矿产研究所,成都610082

出　　处：《地质论评》2008年第3期296-306,共11页Geological Review

基　　金：国家油气专项“中上扬子海相含油气盆地分析与油气成藏条件综合调查评价”项目;国家自然科学基金项目(编号40472070)的成果

摘　　要：作者在分析黔东新元古代早期沉积时限的基础上,结合前人关于Sturtian冰期、南华系底界、青白口系年代学的最新研究成果,指出华南新元古代裂谷盆地早期沉积(板溪群或与之相当的高涧群、芙蓉溪群、丹洲群、下江群、登山群、历口群等)时限为740～820Ma,是南华纪冰期前的非冰成沉积,是Rodinia裂解机制下的填平补齐沉积;而青白口系沉积可能是与Rodinia形成相关的板块碰撞机制下坳陷盆地沉积,南华系是与国际成冰系相对应的冰期沉积,是华南新元古代裂谷盆地的第一个盖层,因此,将板溪群、下江群等归入南华系或青白口系均不合理。由此提出了"板溪系"概念,它包括板溪群或与之相当的一套楔状地层。结合目前华南裂谷盆地开启年龄和南华纪冰期的起始年龄,板溪纪的时限暂定为850～740Ma。板溪系的提出不仅将有利于解决长期存在的南华系划分对比问题,同时也必将有利于新元古代裂谷盆地早期演化及其与Rodinia超大陆裂解、冰期形成等关系的研究和相关重大气候、环境巨变问题的探讨。On the basis of analyzing the depositional ages for rift basin in the eastern Guizhou area in early Neoproterozoic, and the new data about the Sturtian glaciation, the bottom of Nanhuan System, and the geochronology of Qingbaikouan System, writer point out that Neoproterozoic rift basin deposition was not glacial deposition, which was the filling deposition under the condition of Rodinia fragmentation before Nanhuan glaciation, its depositional age was 740 - 820Ma, that Qingbaikouan System should be the deposition of depression basin under the mechanism of plate collision related to Rodinia formation, and that Nanhuan System was the glacial deposition corresponding to Cryogenian, and was the first sedimentary overlay of Neoproterozoic rift basin in South China. Therefore, they are both not reasonable whether Banxi Group, Xiajiang Group and corresponding deposition was labeled as Nanhuan System or Qingbaikouan System. Under this conditions, writer propose a concept of the Banxi System, which is representative for a set of wedge-shaped strata, such as the Banxi Group, Xiajiang Group, Danzhou Group, Gaojian Group, Dengshan Group, Likou Group and so on in South China. The proposal of the Banxi System will not only benefit to strata correlation of the Nanhuan System, which debated for a long time, but also benefit to the research about the relationship between Neoproterozoic rift basin evolution and Rodinia fragmentation, glaciation formatiom, and the probe into corresponding important problems about climate and environment tremendous changes.

关 键 词：黔东新元古代裂谷盆地 板溪群 下江群 青白口系 板溪系 南华系 

分 类 号：P548[天文地球—构造地质学]