L构造岩成因及其岩石流变学意义OA北大核心CSTPCD

L⁃tectonites are characterized by well⁃developed lineations but weak foliations in deformed rocks,commonly associated with constrictional deformation.Constrictional strain is defined by the shortening of two of the principal strain axes.Ideally,L⁃tectonites form when these two shortening strains are nearly equal in magnitude.In contrast,if there is a significant disparity in the magnitudes of these principal shortening strains,foliations may develop even in the presence of two principal shortening strains.Consequently,employing"constrictional strain"as a generalized explanation for L⁃tectonite deformation may risk oversimplification.Furthermore,analyses from the finite strain perspective have suggested that the influence of shear strain on the formation of foliation and lineation is relatively limited.However,the impact of shear strain on mineral orientation and its subsequent inhibition of foliation development remains inadequately understood.This study aims to explore alternative models for the development of L⁃tectonites by reviewing their distribution patterns,analyzing the strain characteristics of various L⁃tectonite types,and investigating potential dynamic boundary conditions.The findings are intended to offer insights into the practical observation and analysis of the kinematic and dynamic implications of L⁃tectonites in regional tectonic contexts by examining their genesis and dynamic boundary conditions.