【作者】 Iraj Vosoughi Niri；

【导师】 何继善；

【作者基本信息】 中南大学 ， 地球探测与信息技术， 2003， 博士

【摘要】 研究区域-沃溪金锑钨矿位于湘西沅陵县沃溪镇内。矿区位于东经110°54′北纬28°32′，面积12平方公里，距常德市西南114公里，距沅陵县东79公里。矿区构造可分为弧形、WE向和NE向隆起构造。矿区位于仙鹅抱蛋背斜的东北翼。出露地层主要为元古界的冷家溪群、板溪群震旦系以及上白垩统地层。在早五岭运动也既众所周知的东安运动的作用下，冷家溪群和板溪群以非完全倾斜角相接触。 为了研究矿区矿床地质、圈出地质构造以及寻找新的远景矿区，已经开展了包括CSAMT、MT和IP在内的地球物理方法。在沃溪矿区在不同的两个阶段(A和B)分别进行了标量可控源音频大地电磁法(CSAMT)，同时在第三阶段(C阶段)进行了国内首次张量可控源音频大地电磁法。可控源音频大地电磁法为矿区提供了矿化层和构造的重要信息。后来详细的地质成图以钻探结果证实这些地球物理方法结果的正确性。对CSAMT测量进行RRI反演，可以有效的生成二维电阻率图像。 在高密度钻探和地质研究结果验证下，沿三条测线近上的矿IP剖面结果证实了CSAMT法的有效性和可靠性。 伪随机多频激电测深与二维CSAMT模拟具有高度一致性。根据已知结果部署的钻孔更加证明了这两种方法结合应用的有效性。 为了研究区域的深部构造，以2公里的点距在20公里长的测线上采集到了11个点的MT数据。结果表明在沃溪矿区下面有一个相对深的延伸隐伏断层。 基于已开展的综合地电方法结果、野外地质和钻探数据,在矿区追索并圈定了一些新的断层,勘探出了三个大规模的矿床。地球物理工作的结果、野外工作以及钻探数据使我们对于矿床地质有了一些新的认识。在提供的模型中,此区域隐伏的主断层(武赫断层)与其它一些主断层如沃溪断层以及新圈定的断层如FZ、F3、F4和甘子坪断层都可以归纳为外延盆地的正常断层。 基于假设的模型,应该在甘子坪断层北部和新田湾断层西北部进行勘探工作。与此同时,东部和西部的探矿也应给予密切的重视。更多还原

【Abstract】 The study area, Woxi gold-antimony, tungsten deposit, is located in Woxi town of Yuanling County of West Hunan, at 110° 54’ E and 28° 32’ N and with an area of 12 square kilometers, 114 km to the southwest of Changde City and 79 km to the east of Yuanling. Structures in the area can be divided into arc, WE-trending and NE-trending structures. The mining area is situated at the northeast wing of Xian’ebaodan Anticline. The outcropped strata are mainly the Proterozoic Lengjiaxi Group, Banxi Group and Sinian system as well as the Cambrian system. Under the role of early Wuling Movement, commonly known as the Dong’an Movement, the Lengjiaxi and Banxi Groups contacted in an incomplete angle.To study geology of the ore deposit, mapping geological structures and looking for new prosperous mineralized zones, geoelectrical methods including CSAMT, MT, and IP were employed. Scalar controlled-source audio magnetotellurics (CSAMT) survey was carried out over the Woxi deposit in two individual stages (A and B). For the first time in China, Tensor CSAMT was employed in the third stage (stage C). The CSAMT data provided important information about the mineralized layers and structures in the study area. Follow-up detailed geological mapping and drilling works verified most of the achieved results. In addition, RRI inversion was used as an effective method for producing 2-D resistivity images from CSAMT measurements made along surface traverses.Near-ore IP profiling results along three survey lines subjected to intensive drilling and geological studies show efficiency and reliability of the implemented CSAMT method.Pseudo-random multi-frequency IP sounding shows high conformity with the produced 2-D CSAMT models. The drilled boreholes based on the achieved results demonstrate the effectiveness of the combined use of both methodsMT data was collected in 11 stations on 20 km line with 2 km spacing to study deep structures of the region. The result shows a relatively deep concealed extension fault under the Woxi deposit.As indicated by employed integrated geoelectrical methods outcome, field geology and borehole data, some new faults were traced and mapped and two important large-scale reserves were explored in the area. The results of geophysical work along with fieldwork and borehole data directed us to new idea about geology of the deposit. In the offered model the concealed main fault in the area, named Wuhe (武赫) along with other main faults in the area such as Woxi Fault and other newly mapped, F2, F3, F4, and Ganziping faults are all were classified as normal faults in an extensional basin.Based on the proposed model, exploration should be carried out towards north of Ganziping and northwest of Xintianwan Faults. Meanwhile, prospecting in the east and west should also be paid close attention.更多还原