造山带的网结状构造样式

网结状构造样式是造山带地壳结构的一个重要特征,表现为线状强应变带与夹持其间的透镜状弱应变域规律组合格式。这种网结状型式在几何学上具有尺度不变性,并具三维特征,理论分析和实际观察指出,这种网结状构造样式,是在应变软化作用及变形分解作用控制下递进发育而成的,而造山带地壳结构的不均一性、组成造山带岩石的流变学特征以及变形物理环境,又是控制应变软化及变形分解作用的主要因素。

ANASTOMOSING TECTONIC PATTERNS IN OROGENIC BELTS

The most outstanding tectonic features of orogenic belts are their anastomosing tectonic patterns with lens-shaped domains of low strain separated by anastomosing belts of high strain. The Qinling terrane of the Xixia area, Henan province, represents an excellent example of such tectonics. The patterns may be observed at all scales of deformation in the orogenic belts. Numerous variables and factors, such as the variability in the rheological properties and contrasting flow strengths of rocks across the orogenic belts, the initial composition and fabrics anisotropy and heterogeneous of rocks and terranes, affect the behavior of these forms. It is emphasized that a progressive strain softening or deformation partitioning directly related to the tectonometamorphic and rheological evolution of the orogenic belts is probably responsible for the anastomosed tectonic patterns. Their understanding thus provides insight into the crustal texture and thermodynamic evolution of the orogenic belts.