铜陵矿集区地壳浅表结构的地震层析研究

为了给铜陵矿集区成矿理论研究提供更多的地壳浅表结构信息 ,以及试验地震层析成像方法在金属成矿区的应用效果 ,利用高精度反射地震资料中的初至波走时数据 ,对铜陵矿集区地壳浅表结构进行了层析成像试验研究。结果显示 :矿集区浅表地壳的速度分布存在着丰富的结构变化特征 ,层析结果给出的速度变化特征与地表观察到的地质、构造、岩体和矿体分布存在着良好的对应关系。研究结果表明 ,初至波走时层析成像方法可以为深部隐伏矿床的勘探研究提供丰富的地壳浅表结构信息。笔者认为 ,今后还应考虑同时采用初至波和反射波走时 (甚至波形 )资料进行层析反演的方法 ,来进一步提高较深部 (>5 0 0m)地质目标的分辨能力。

Tomographic Study of Shallow Structures in Tongling Metallogenic Province

To acquire more information about shallow structures for the metallogenic study of the Tongling copper_iron belt, the authors used first arrival time data picked from high_resolution reflection profiles in a tomographic approach in this study. The results reveal a significant variation in seismic velocity in the shallow crust, which coincides well with the geological structures and the distribution of intrusive bodies and orebodies observed at shallow places. It is held that the travel time tomography is an effective technique in the study of near_surface structure and in the exploration of mineral resources beneath the crystalline crust. However, the first arrival time tomography presented in this paper appears not sufficient for the detection of geological objects at greater depths (>500 m) due to the lack of vertical velocity gradient in this region. To gain better results, the authors advocate the exploring of some newly emerging tomographic techniques, which make use of reflection phases and/or waveform, in the further studies.