东秦岭铁炉子断裂的新活动特征  

CHARACTERISTICS OF RECENT ACTIVITY OF THE TIELUZI FAULT IN EAST QINLING MOUNTAINS

作　　者：周厚云[1] 韩慕康[2] 侯建军[3] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640 [2]北京大学城市与环境学系,北京100871 [3]北京大学地质学系,北京100871

出　　处：《地震地质》2001年第3期390-398,共9页Seismology and Geology

摘　　要：描述了东秦岭山地铁炉子断裂新活动的方式、表现以及断裂所在地区的新构造应力场。从河流阶地所反映的断裂在水平方向和垂直方向上的错距和错动速率看 ,铁炉子断裂的新活动主要表现为左旋走滑活动 ,其水平活动规模比垂直活动大一个数量级 ;该断裂垂直活动比较明显的地方是沿盆地发育的地段 ;断裂活动有加速的趋势。铁炉子断裂的新活动方式很可能是由于印度板块向北碰撞挤入欧亚板块及由此造成青藏高原隆起 ,使中国东部地块向东或东南方向差异性滑移的结果。This paper describes the pattern and appearance of the recent activity of the Tieluzi Fault and recent stress field in East Qinling Mountains. The recent movement of the Tieluzi Fault has resulted in the 'S'-shaped turning of streams, displacement of terraces and Neogene sediments along the fault. The recent stress field over the East Qinling Mountains was dominated by SEE-trending compressive stress. The amplitude and rate of faulting were determined on the basis of the differences of elevation, lateral displacements and ages of terraces. From our investigations and measurements, the following conclusions can be drawn: 1) The recent movement of the Tieluzi Fault was dominated by left-lateral strike-slipping. Since the formation of the third terrace, the left-lateral offset along the Tieluzi Fault amounted to several hundreds meters, while its total vertical displacements were within 30 meters. It means that the lateral movement was at least a factor of magnitude larger than the vertical movement; 2) The Tieluzi Fault displayed apparent vertical movements at the places where basins were developed, while at the places where no basin was developed, its vertical movement was relatively weak; 3) The recent movement of the Tieluzi Fault seems to have accelerated since the formation of the third terrace. For example, the rate of lateral displacement of the Tieluzi Fault was in the range of 5～7mm/a since the formation of the third terrace, while since the formation of the first terrace, it was in the range of 8～12mm/a. It is suggested that the recent movement of the Tieluzi Fault was the result of northward squeezing of the Indian Plate beneath the Eurasian Plate, as suggested by Tapponnier et al (1990), and that the recent movement of the Tieluzi Fault reflects the eastward or southeastward differential movement of East China blocks.

关 键 词：东秦岭 铁炉子断裂 新构造应力场 断裂活动方式 河流阶地 

分 类 号：P542.3[天文地球—构造地质学]