论秦岭碰撞造山作用对华北石炭二叠纪海侵过程的控制

The controls of the collisional orogenesis in the Qinling Mountains on the Carboniferous-Permian transgressional processes in North China

关键词:  碰撞造山作用  海侵  残余海盆  石炭二叠纪  秦岭造山带  华北

Key words:  collisional orogenesis  transgression  residual sea basin  Carbonifreous-Permian  Qinling orogenic belt  North China

摘要:

晚古生代一三叠纪是秦岭造山带主造山作用的碰撞造山期,其中石炭二叠纪是点接触至面接触碰撞的阶段。华北石炭二叠纪发育有4次较大规模的海侵,时代分别为C₁²-C₂^1-1,C₂^1-2-C₂²,P₂¹和P₃¹。岩相古地理制图及海侵沉积单元空间展布规律的分析结果表明,海侵来自华北地块南侧的秦岭残余海盆,且海侵具有由东向西逐渐推进之势。这一海侵过程是受华北地块东低西高的古地理格局及秦岭造山带以小秦岭地区为中心呈双剪刀状反向穿时碰撞造山作用控制的结果。

Abstract:

The Late Palaeozoic-Triassic is the collisional orogenic period of the major orogenesis in the Qinling orogenic belt,where the collisional orogenesis operated in the forms of point contact and plane contact during the Carboniferous-Permian when four phases of large-scale transgressions once occurred in North China,including C₁²-C₂^1-1,C₂^1-2-C₂²,P₁¹ and P₃¹,respectively,The research of sedimentary facies and palaeogeographic mapping and spatial distribution of the transgressional depositional units indicate that the transgressions originated in the Qinling residual sea basin south of the North China block,and progressively prograded from east to west. These transgressional processes are generally governed by both the palaeogeographic framework of the North China block being higher in the west and lower in the east,and shear reverse diachronous collisional orogenesis centred by the Xiaoqinling region within the Qinling orogenic belt.