长江中下游金属矿集区近地表速度结构层析成像实验及应用

利用矿集区获得的小道距、长排列接收的地震反射初至波走时数据,运用层析成像方法,首次得到长江中下游典型金属矿集区——庐枞火山岩盆地近地表1000m以上的交叉速度结构。各剖面精细的速度结构揭露出庐枞矿集区隐伏的正长岩体顶界面深度与起伏形态,发现岩体顶面凸起及陡变化部位与矿体分布存在着明显的对应关系,罗河铁矿、小岭铁矿、龙桥铁矿、马鞭山铁矿处对应着高速层顶界面的凸起位置。罗河断裂在lz06-1线与lz06-3线表现为明显的横向速度变化界面。这些结果表明,长排列的深地震反射初至波走时层析成像方法能够为金属矿集区深部隐伏矿床的勘探研究提供丰富的地壳浅表结构(0～1000m)信息。

Tomography imaging experiment of Iron-polymetallic deposits near-surface velocity structure and its application in the lower and middle Yangtze Reaches

The CAGS has finished four corss-deep seismic reflection profiles before the Chinese New Year of 2007 in the Luzhong Iron-polymetallic deposits in the lower and middle Yangtze Reaches. This paper utilized the first break-arrivals of these long-offset shot records by means of tomography method to build the near-surface (~1000m) velocity model. The imaging results showed us the depth and undulated shape of the tip interface for the lie concealed syenite. We found the heave of rock bodies and steep changing part has well obvious corresponding relationships with ore body distribution. The heave of the high velocity corresponds to the Luohe, Xiaoling, Longqiao and Mabianshan Iron-polymetallic deposits. The Luohe fault is an obvious horizontal velocity transformation interface from the line lz06-1 and lz06-3. This research results indicate that the long-offset first arrival travel-time tomography method can provide abundant crustal shallow structure information (0~1000m) for the study of prospect for the deep lie concealed deposits and point out the potential prospecting for Iron-polymetallic deposits in Luzhong area, Anhui province.