Abstract:

The Lianyunshan complex, cropping in the JiulingMufushan range in the northeastern Hunan Province, belongs to the paleo-Proterozoic crystalline basement rocks. By means of field structure analysis, petrofabrics and fractal dimension analysis of quartz, the authors have carefully studied the deformation feature and mechanism of the Lianyunshan complex in the northeastern Hunan Province. The results are : （1）the Lianyunshan complex has undergone two stages of the earlier ductile shear and the later ductile reconstruction. Plastic flow deformations of quartz grains are mainly rhombohedral slip; （2）strain rate gradually reduces from the earlier structural schist (gneiss) of middle strain rate（10^-8.8s^-1）to the later ductile reconstruction striped migmatite of low strain rate（10^-12s^-1）;（3）plastic flow deformation mechanism of the rocks not only reflects amphibolite facies formed in the midupper crust environment, but also suggests that the deeper crustal material in the Xuefeng land have not yet been uplifted.

Key words: rheology, strain rate, Lianyunshan complex, northeastern Hunan Province