West-trending ductile shear zone in Lujia Hebei

The west-trending ductile shear zone in Lujia Hebei Province is located under the old bridge of Lujiahe Township House, Guifeng Mountain Park. Its area is about 19 km long and its width is about 1 km. The wall rocks are granitic gneiss of the Middle-Neoproterozoic Hongan Group, trending northwest and tending south-west with obvious zonation. They are tectonic gneiss belt, mylonite belt, shear fold belt, breccia migmatite belt and eyeball gneiss belt from Dengjiashan to Lujiahe. In the zone, primary mylonite and straight gneiss are dominant, and a large number of rootless folds and various S-C fabrics are developed. Generally, amphibolite facies is a ductile nappe shear zone from south to north.

(Note: Ductile shear zone is a high strain zone with strong plastic rheology and rotational strain characteristics, which is widespread in the deep crust (more than 10-15 km). It is also called ductile fault.