摘要:
新疆—甘肃—内蒙古相邻的天山—北山衔接区由于分属不同行政区域,在地层单位划分上出现差别.通过地层特征对比,认为从天山东段至北山,地层具有连续性.统一的地层系统可为正确划分构造单元提供重要依据:太古宇—古元古界北山杂岩(Ar2Pt1Bc)、中元古界长城系星星峡群(ChX)、古硐井群(ChG)和蓟县系卡瓦不拉克群(JxK)、平头山组(Jxp)构成星星峡-旱山微板块中心的地块;太古宇-古元古界敦煌杂岩(Ar2Pt1Dc)及少量中元古界长城系铅炉子群(ChQ)构成敦煌微板块中心的地块;红柳河-牛圈子-洗肠井蛇绿岩带被厘定为早古生代缝合带的辅助依据,是其南侧保存有指示南北两个板块开裂前伸展拉张浅海-次深海环境沉积的寒武系含磷钒铀锰矿地层,证明该带代表南北两个板块间分裂和聚合的位置.
关键词:
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地层对比
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构造单元
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北山
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天山
Abstract:
The stratigraphic division of Beishan mountains and east Tianshan mountains,in the Conjunction Area of Xinjiang Uygur Autonomous Region,Gansu Province and Inner Mongolia Autonomous Region,is different,because they belong to different administrative regions.But the stratigraphic correlation indicates that the stratum of east Tianshan mountains and Beishan mountains is continuous,and this can provide an important basis for tectonic division.Theses tectonic units,such as Archean-Paleoproterozoic Beishan complex (Ar2Pt1Bc),mesoproterowic Changcheng system Xingxingxia group (ChX) and Gudongjing group (ChG),Jixian syst}n Kawabulake group (JxK) and Pingtoushan formation constitute the center of Xingxingxia-an sham micro-pant,and Dunhuang micro-lant ism ainly made up of Archean-PaleoproterowicDunhuang complex (Ar2Pt1Bc) and a little mesoproterozoic Changcheng system Qianluzi group (ChQ).The accessory basiswhat the Hongliuhe-Niuquanzi-Xichangjing ophiolite beltwas confirmed Eopaleowic suture wne is that there is Precambrian stratum of containing phosphorus-vanadium-uranium-manganese in the south side of this belt,which indicate the extension and shallow-subdeep water sedimentary environment before cracking of the south plate and the north plate This evidenceproves that Hongliuhe-Niuquanzi-Xichangjing ophiolite belt lies in the location where the south plate and the north plate was splined and aggregated.
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