中国石炭纪岩石地层划分和对比

LITHOSTRATIGRAPHIC SUBDIVISION AND CORRELATION OF THE CARBONIFEROUS IN CHINA

《国际年代地层表》中的石炭系包含密西西比亚系和宾夕法尼亚亚系,各分3统,共7个阶,是全球煤炭、油气等重要能源资源的富集层位。为了统一标准、提高对比精度,并服务于资源勘探开发,本文在详细归纳前人研究的基础上,结合最新的研究成果,对中国石炭纪地层区划、主要剖面的地层划分和对比进行了系统梳理;将中国的石炭系划分为4个地层大区,分别为准噶尔—兴安大区、塔里木—华北大区、羌塘—华南大区和西藏—滇西大区,又进一步将各地层大区划分为11个地层区,并列举了81条地层剖面。基于生物地层学和年代地层学的时间约束,详细厘定了中国石炭系不同地层分区之间的岩石地层划分和对比框架。准噶尔—兴安大区石炭系以浊积岩和火山岩为主,是中亚造山带的重要组成部分;华北—塔里木大区除塔里木北缘和华北台地西南部保存有深水沉积外,均为稳定的滨浅海沉积,其中华北分区缺乏密西西比亚系,宾夕法尼亚亚系为海陆交互相沉积,发育明显的海侵-海退序列;西藏—滇西大区为冈瓦纳大陆东北缘沉积区,密西西比亚系以陆棚碳酸盐岩或碎屑岩为主,宾夕法尼亚亚系则常常缺失;羌塘—华南大区石炭系序列最为完整,尤其华南地区,以碳酸盐岩台地沉积为主,化石丰富多样,是国际石炭系对比的重要标准。

The Carboniferous, which hosts significant coal and petroleum reserves around the world, consists of Mississippian and Pennsylvanian, and is further subdivided into six series and seven stages. The Carboniferous strata are well-developed in China with various types of sedimentary facies. In order to reconcile the standards, improve the correlation resolution, and better serve for reserve exploration in China, this study systematically reviewed previous studies, and re-organized the Carboniferous lithostratigraphic subdivisions, distributions, and correlations. The Carboniferous in China is subdivided into four stratigraphic provinces(i.e., the Junggar-Hingga, Tarim-North China(NC), Qiangtang-South China(SC), and Tibet-Western Yunnan) and eleven stratigraphic sub-provinces in the context of 81 stratigraphic sections. Based on age constraints of biostratigraphy and chronostratigraphy, the lithostratigraphic subdivisions and correlations of Carboniferous are clearly shown.(Ⅰ) The Junggar-Hingga stratigraphic province belongs to the continental margin of craton,where the Carboniferous mainly consists of turbidites and volcanic rocks.(Ⅱ) The Carboniferous strata in Tarim-NC stratigraphic province are predominantly composed of shallow-marine facies, in addition to some deep-water deposits in limited areas. The Mississippian is absent in the NC sub-province, whereas the Pennsylvanian there mainly consists of alternative marine-continent deposits with obvious transgression-regression sequences.(Ⅲ) The Tibet-Western Yunnan stratigraphic province, located on the northeast margin of Gondwana continent, contains well-preserved Mississippian shelf carbonates and siliciclastic rocks, but missing the Pennsylvanian.(IV) Compared to other stratigraphic provinces, the Carboniferous sequences are well-developed in Qiangtang-SC stratigraphic province, especially in South China, which are dominated by carbonate platform deposits. The rich fossils in South China are important criteria for the Carboniferous correlation in the global scale.