掀斜块体滑脱深度的几何学研究

GEOMETRICAL STUDY ON DETACHMENT DEPTH OF TILTED BLOCK

本文从几何学的角度,根据掀斜块体长度、掀斜角、脊的隆起量和边界断层倾角等几何要素,推导出了计算掀斜块体滑脱深度的表达式。结果表明,旋转平面状正断层围限块体的滑脱深度与脆韧性转换带上顶面深度一致,为10—15公里;铲形正断层围限块体的滑脱深度达到或超过脆韧性转换带深度,为20—30公里。

The formula for calculating the detachment depth of a tilted block is established in geometrical aspect from the length of tilted block, tilt angle, uplift displacement amount of the crest and dip angle of the border fault. The calculated result shows that the detachment depth of the tilted block controlled by rotational planar normal fault is about 10-15km, which is the same as the depth of the top surface of brittle-ductile transition zone; the detachment depth of the tilted block controlled by listric normal fault is about 20-30km, which reaches and exceeds the depth of brittle-ductile transition zone.