柴北缘欧龙布鲁克地块寒武系-奥陶系的重新厘定  

Redefinition of the Cambrian-Ordovician Strata in the Olongbuluck Area, Northern Margin of the Qaidam Basin

作　　者：陈青[1] 李海平 董云鹏[1] 冯乔[3] 何登峰[1] 陈浩[1] 

机构地区：[1]西北大学大陆动力学国家重点实验室/地质学系,陕西西安710069 [2]陕西省地矿局区域地质矿产研究院,陕西咸阳712000 [3]山东科技大学地质科学与工程学院,山东青岛266510

出　　处：《地质与勘探》2013年第5期825-835,共11页Geology and Exploration

基　　金：中石化重大项目<柴达木区块构造-岩相古地理研究与编图>(编号YPH08105)资助

摘　　要：通过对柴达木盆地北缘欧龙布鲁克地区的野外地质调查和精细剖面测量,根据岩石组合、沉积构造、地层接触关系及新发现的生物化石特征,对分布于该地区的早古生代寒武纪-奥陶纪岩石地层进行了详细的划分对比和重新厘定:①欧龙布鲁克群只发育寒武系的第三统和顶部的芙蓉统,缺失底部的纽芬兰统和第二统;②多泉山组为下奥陶统,石灰沟组属于中奥陶统;③原划分的中奥陶统大头羊沟组属于构造改造的断片,不符合建组原则,应弃用;④通过柴达木盆地周缘分布的早古生界地层的区域对比,认为欧龙布鲁克地块之上出露的寒武系-奥陶系(海相碳酸盐岩沉积建造)与滩间山群、祁慢塔格群和纳赤台群(中基性火山岩建造)分别代表了不同构造背景-沉积环境的产物。本研究工作一方面为建立该地区合理和行之有效的岩石地层和年代地层系统提供依据,另一方面为柴达木盆地北缘寒武系-奥陶系地层层序-岩相古地理演化及油气资源潜力评价等研究提供详实的资料,同时也为深化塔里木东南缘陆块群的构造演化提供科学依据。We have carried out field investigations and precise profile measurements in the Olongbuluk area, northeru margin of the Qaidam basin. In combination with rock assemblages, sedimentary structure, stratigq＇aphie contact relationship and newly discovered fossils, we made a detailed division, and comparison, and redefined the Cambrian-Ordovician strata. The results show that ： （ 1 ） The Olongbuluck Group only contains the third series and Fu- rongian series of Cambrian, and lacks Terreneuvian and second series. （2） The Duoquanshan and Shihuigou Formations are of the lower and middle Ordo- vician, respectively. （3） The original division of the middle Ordovician Datouyanggou Formation should be fragments of structural reformation, which does not match the principle of establishing formation and should be abandoned. （4） Through regional stratigraphie comparison of those blocks around the Qaidam basin, we suggest that the Cambrian-Ordovician strata are exposed over the Olongbuluck block （marine carbonaterock formation）, Tanjianshan Group, Qi- mantage Group, and Naijtal Group （intermediate-acid volcanic construction）, which represent the products of different structural settings and sedimentary environments. This study provides an important basis not only for establishing rational and effective lithostratigraphic and chronostratigraphic systems, but al- so for the evolution of stratigraphic sequence-lithofacies palaeogeography and hydrocarbon resource evaluation of Cambrian-Ordovician in the northern Qaidam basin. Furthermore, it also provides evidence for better understanding tectonic evolution of blocks in the southeast margin of the Tarim basin.

关 键 词：柴北缘 寒武-奥陶纪 欧龙布鲁克群 多泉山组 石灰沟组 

分 类 号：P53[天文地球—古生物学与地层学]