鲁西伸展构造──一个中－上地壳板块的提示

LUXI EXTENSIONAL STRUCTURE──IMPLICATION FOR A MIDDLE-UPPER CRUST PLATE

摘要:

鲁西伸展构造的主要特征是发育掀斜断块，断块由凸起和凹陷组成，凹陷部分的半地堑盆地，走向由ＮＷ转为ＥＷ，北深南浅，地层关系北断南超，沉积中生界和老第三系，盆地基底是前寒武纪结晶岩石和古生界。由侏罗纪至老第三纪，伸展构造的活动持续了约１５０Ｍａ。在如此长的时间里要保持掀斜断块运动特征的一致性，除了区域性的伸展运动特征保持不变外，掀斜断块本身的均衡性不被破坏是必须的。断块的密度在掀斜过程中不会有多大改变，保持均衡的关键在于断块的大小、形状和空间方位不发生过大变化；而掀斜断块发育剥蚀端和沉积楔，以及相应的在地下部分发育增生楔和削蚀端，可以满足这样的条件。河南和安徽区段发育同类型构造，它们与鲁西伸展构造联合显示出一个规模宏大的伸展构造系统，从而证明鲁西－淮河平原中－上地壳板块的存在。这个板块的前缘消减现象明显，发育压剪带，“大别山块体”可能是“挤出体”。

Abstract:

The basic feature of Luxi extensional structure is the development of lifted-dipping blocks which are made up of swell and sag. The semi-gvaben basin in sag area has a strike changingfrom NW to EW,deep in north and shallow in south depth and stratigraphic relationships offaulting in north and overlapping in south. Its sedimenfary rocks Consist of mesozoic erathem andtertiary System. The basin basement Comprise precambrian crystalline rocks and palaeogoicerathem. From Jurassic to Palaogene the extensional ...