摘要:
通过区域地质调查和研究,认为前人所建立的的祁漫塔格群或滩间山群包括了不同时代的浅变质碎屑岩、中酸性火山岩及基性-超基性岩。根据在东昆仑原划奥陶系祁漫塔格群第一亚群(下部碎屑浊积岩)中采集到早志留世笔石化石组合(这是首次证实东昆仑地区存在志留系地层)及同位素测年资料(鸭子大板火山岩年龄),其时代包含了奥陶纪、志留纪和三叠纪等,根据中国地层指南及中国地层指南说明书和地层清理,对祁漫塔格群进行了解体,将其重新厘定为奥陶纪滩间山群(OT)、志留纪白干湖岩组(Sb)弧后盆地复理石沉积和鸭子泉组(Sy)岛弧火山岩、石炭纪鸭子大坂硅质岩(Si)、三叠纪鄂拉山组(T3e)、蓟县纪狼牙山岩组(Jxl)和南华—奥陶纪阿牙克库木湖蛇绿混杂岩[(Nh—O)aΣ]。该成果对于祁漫塔格地区早古生代地层划分对比、构造演化提供了重要新证据。
Abstract:
Through regional geological survey and research,the authors consider that the Qimantage Group or Tanjianshan Group,established by predecessors,include epimetamorphic clastic rock,intermediate acidity volcanic rock and basic-ultrabasic rock in different epoch.Based on the graptolite fossil assemblage of Silurian collected in the first subgroup of formerly named Ordovician Qimantage Group at east Kunlun (it is the first time to prove that there exists Silurian strata) and isotope dating information (Yazidaban volcanics age),it is suggested that its age includes Ordovician,Silurian and Triassic etc.According to stratum guidelines and stratum cleaning,authors dismember the Qimantage Group and redefined it as Tanjianshan Group of Ordovician system (OT),Baiganhu formation of Silurian system (Sb) back-arc basin flysch deposit and Yaziquan formation (Sy) island arc volcanics,Yazidaban silica rocks (Si) of carboniferous system,Elashan formation of triassic system (T3e),Langyashan formation of the Jixianian system (Jxi>l) and Ayakekumu lake ophiolitic melange of Nanhua-Ordovician system [(Nh—OaΣ].The result provides some new important evidences for the stratigraphic division and correlation,structural evolution of early-palaeozoic at Qimantage area.
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