摘要
地壳浅表走滑构造系统发育于多种类型的地球动力学背景,不仅具有较强地震危害性、也富集油气矿产等资源。自20世纪初以来,基于地质构造过程自相似性和“无理有效性”的砂箱物理模型为走滑构造系统演化特征与机制等研究提供了独立有效的手段。自然界走滑构造系统动力学上可分为板缘构造转换断层和板内走滑断层体制,空间几何学上可分为走滑断层弯曲类和走滑断层叠置类。基于吕德尔剪切和弥散性剪切砂箱物理模型实验共同揭示出,走滑剪切系统主走滑变形位移带发育五类断裂/破裂体系,即R型破裂、R′型破裂、P型剪切、张破裂和Y型破裂,尤其是在弥散性剪切变形过程中发育大量的RL和RL′型斜切剪破裂。浅表走滑剪切构造系统分段性及其走滑转换带差异变形特征受控于基底走滑断层应力‒应变条件沿走向差异变化的特性,基底断层几何学(弯曲/叠置性、间隔性等)、砂箱动力学特性(纯走滑剪切、拉分走滑和挤压走滑剪切)、非均质性砂箱物质特征(黏土和膏岩等)、基底非均一性(塑性基底物质几何学等)等对走滑构造变形过程具有明显的控制作用。砂箱物理模拟实验能为走滑构造系统运动学、变形特征与机制等提供较好的解释模型,能有效再现走滑构造形成演化的四维过程与机制,在地震灾害机理、油气勘探等方面将发挥越来越重要的作用。
Strike-slip deformation in the shallow crust occurs in diverse geodynamics and exhibits complex geological features,such as earthquakes,hydrocarbon accumulation,etc.Since the 1900s,analogue modelling has become a powerful and indispensable tool which can provide an integrated picture of strike-slip deformation based on self-organization and unreasonable effectiveness of tectonics.In nature,the strike-slip system can be divided into the boundary transform and intraplate strike-slip shears in geodynamics,and divided into bend-type and stepover-type strike-slip shears in geometry.Based on the analogue modelling of Riedel and distributed strike-slip deformation,five type shears or strike-slip faults across the principal displacement zone(PDZ)can further be recognized which include R-shears,R′-shears,P-shears,tensile shear and Y-shear.RL-and RL′-shears are common in distributed strike-slip deformation.Previous analogue modeling researches have explored the role of main parameters governing strike-slip deformation,including the properties of basement fault(bend and stepover),kinematics(pure strike-slip,transpression and transtension),surface processes(erosion and sedimentation),the properties of material(wet-clay,silicone),and inhomogeneous basement etc.Nowadays,analogue modelling has become a critical gateway in researches of mechanical and structural evolution of strike-slip system in the shallow crust,as well as in the earthquake and hydrocarbon exploration.
作者
谢玉洪
XIE Yuhong(China National Offshore Oil Corp.,Beijing 100010,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2021年第6期1127-1145,共19页
Geotectonica et Metallogenia
基金
国家科技重大专项(2016ZX05024)资助。
关键词
砂箱物理模型
走滑变形
吕德尔剪切
弥散性剪切
Analogue modelling
strike-slip deformation
Riedel strike-slip shear
distributed strike-slip shear
