Abstract:

Lishui Nanling Basin is a Mesozoic pull apart basin which possesses two sedimentary depression.The boundary faults of the basin's two sides are left step sinistral en echelon strike slip faults with NNE strike.The basin has similar origin to that of Ningwu pull apart basin. They constitute a pull apart basin set.The basin has following features:(1)The stratigraphic thickness is up to 6 000 m,and the sedimentation rate is more than 690 m/Ma.(2)The sedimentary facies show evident asymmetry in basin's plane and cross sections.(3)The palaeocurrent directions of the basin margins point to intra basin,those in the axial region of the basin are accord with the basin axis.Along the palaeocurrent directions,the content and the size of the gravel decreases.(4)Strike slip movement of the boundary faults led to the fan/source displacement and the continuous change of the palaeocurrent directions.(5)Volcanic rocks changed from calc alkaline into alkaline into alkaline in the basin,indicating the change of it's tectonic background from compression to extension.