摘要:长江中下游成矿带是我国重要的铁铜多金属矿产资源基地，燕山期中酸性岩浆岩对铜、铁、金等各种内生金属矿床的形成起着举足轻重的作用，识别和厘定岩浆岩体特别是隐伏岩体的三维分布形态对成矿动力学研究和深部找矿预测工作都有着重要意义。我们采用重磁三维物性反演技术，获得长江中下游成矿带磁化率和密度差三维模型，根据物性与岩性对应关系，识别和分析了区内岩浆岩体三维空间结构。推测了区内存在5个主要的岩浆活动中心，探讨了岩浆流动形式与轨迹。根据重磁三维反演反映的长江中下游岩浆岩三维分布特征，结合区域莫霍面、均衡重力异常和重磁多尺度边缘检测结果，以及区域成矿背景，预测了5个找矿远景区。结果表明，重磁三维反演技术是一种行之有效的岩浆岩体识别手段，通过对反演所得磁化率、密度分布情况的分析，可识别、圈定隐伏或半隐伏岩体，并可定量获取岩体三维形态特征，从而为寻找与火山岩、侵入岩体有关的金属矿产提供指示信息。
关键词: 长江中下游成矿带/
重磁三维反演/
岩浆岩体
Abstract:The Middle and Lower Reaches of Yangtze River metallogenic belt is one of the major copper resource bases in China. Yanshanian intermediate-acid magmatic rocks play an important role in the formation of various endogenous metal deposits such as copper, iron and gold. It is of great significance for the study of metallogenic dynamics and deep prospecting to identify and determine the three-dimensional distribution of magmatic rocks, especially concealed rock body. Based on gravity and magnetic three-dimensional physical inversion technique, a three-dimensional model of magnetic susceptibility and density difference in the Middle and Lower Reaches of the Yangtze River is obtained. Then according to the correspondence between physical properties and lithology, the three-dimensional structure of igneous rock body in the area is identified and analyzed. It is speculated that there are five main magmatic activity centers in the area, and the form and trajectory of magma flow are discussed. Finally, according to the three-dimensional distribution characteristics of the magmatic rocks in the Middle and Lower Reaches of the Yangtze River, combined with the regional Moho discontinuity, the isostatic gravity anomaly and the multi-scale edge detection results of the gravity and magnetic, and the regional metallogenic background, five prospecting prospects are predicted. The above results show that the gravity and magnetic three-dimensional inversion technique is an effective means for identifying magmatic rock mass. By analyzing the magnetic susceptibility and density distribution of the inversion, the concealed or semi-concealed rock mass can be identified and delineated. The three-dimensional morphological characteristics of the rock mass can be quantitatively obtained, thus providing indication information for finding metal minerals related to volcanic rocks and intrusive rocks body.
Key words:The Middle and Lower Reaches of Yangtze River metallogenic belt/
3D inversion of gravity and magnetic/
Plutons
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