新世纪构造地质学两大支柱理论: 最大有效力矩准则与变位形分解

传统构造地质学用摩尔-库伦准则和贝克尔的应变椭球体理念分别解释地壳中的脆性断层和塑性变形，将变形局部化的韧性剪切带形成解释为平行应变椭球体的圆切面，却无法解释变形局部化的共轭剪切带稳定夹角~110°面对应缩短方向。变形局部化是独立于脆性和塑性变形外的变形领域，受最大有效力矩准则控制。20世纪末提出的变位形分解理念，摆脱连续介质力学的束缚，合理地说明广泛存在的走滑断层平行俯冲带或逆冲断层带。非均匀变形和非连续介质力学理念的建立，为地质学与力学的结合开辟了新的前景。文章试用上述两理念概略分析中国和邻区中新生代构造格局，以期引发讨论。 

Two pillar theories of structural geology in the new century: the MEM criterion and the deformation partitioning

Geologists used the Mohr-Coulomb criterion and Becker''s strain ellipsoid to explain brittle fractures and plastic deformation, respectively, in traditional structural geology, and considered that formation of ductile shear zones was parallel to the circular sections of a strain ellipsoid. However, they failed to explain the stable angle ~110° facing contraction direction between conjugate ductile shear zones due to deformation localization. In fact, deformation localization is an independent deformation category controlled by MEM-criterion besides brittle fracturing and plastic deformation. The concept of deformation partitioning put forward at the end of twentieth century got rid of the bondage of continuum mechanics, and successfully explained the widespread phenomenon, strike-slip faults parallel to subduction zones or fold-and-thrust belts. The establishment of inhomogeneous and discontinuous medium mechanics opens up a new prospect for the combination of geology and mechanics.