万福变质核杂岩韧性剪切拆离带的韧性减薄量

Ductile Thinning of Wanfu Metamorphic Core Complex Ductile Shear Detachment Zone

万福变质核杂岩韧性剪切拆离带与辽南变质核杂岩相毗邻,位于辽东半岛北部。韧性剪切拆离带从浅部到深层依次发育糜棱岩、糜棱化岩石及条带状片麻岩。以长石碎斑为标志体的糜棱岩三维有限应变测量显示,X轴一直伸长,Y轴保持不变,Z轴一直缩短。极莫尔圆估算的韧性剪切拆离带内糜棱岩及糜棱岩化岩石的运动学表明,糜棱岩面理和线理形成时的运动学涡度为0.74~0.96,平均为0.86,表明万福韧性剪切拆离带形成以简单剪切为主,结合三维有限应变测量结果,可知万福韧性剪切拆离带为一条加长-减薄型剪切带。以有限应变测量与运动学涡度估算为基础,初步估算了该韧性剪切拆离带的韧性减薄量,沿剪切拆离方向,韧性减薄量从8%增加到29%,且韧性减薄量与运动学涡度负相关。

The Wanfu metamorphic core complex ductile shear detachment zone is located at the northern of the Liaodong peninsula and adjacent to Liaonan metamorphic core posed of mylonites, mylonites rocks and banded gneisses from ment using the feldspar porphyroclasts show that the principal that the X-axis lengthening, the Y-axis remaining unchanging complex. The ductile shear detachment zone corn- the shallow crust to deep crust. The strain measureaxis X 〉 Y （ ≈ 1 ） 〉 Z of the strain ellipsoids and and the Z-axis shortening. The kinematic vorticity （ Wk ） values, estimated by the Polar Mohr diagram, changed from 0.74 to 0.96 with an average of 0.86, which suggest that the Wanfu ductile shear detachment zone experienced simple-dominated general shearing forming the mylonite foliation and lineation. Based on the finite strain measurement and kinematics vorticity estimation, the ductile thinning ranged from 8% to 29% alone the sense of detachment, and has negative correlation with the kinematic vorticity.