摩天岭地块及邻区深部电性结构与矿产分布

发布时间：2018-03-11 01:30

本文选题：摩天岭地块　切入点：大地电磁测深　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：摩天岭地块位于陕甘川三省邻接区,构造上处于扬子地块西北缘,松潘-甘孜构造带东北,北面为西秦岭造山带。摩天岭地区多金属矿产资源丰富,但是矿产开采主要集中在地表及浅部,隐伏矿产勘探程度较低,已有矿产资源储备不能满足经济社会发展的要求,主要原因是对其深部构造及成矿来源研究不足。大地电磁测深以天然大地电磁场为场源,通过宽频大地电磁测深与长周期大地电磁测深相结合,能有效探测地壳及上地幔的深部电性结构特征,可对研究区深部的物质来源与运移提供地球物理依据。论文依托龙门山构造带深部地质调查项目,利用横跨摩天岭地块南北向的榆中-剑阁及东西向的松潘-汉中两条大地电磁测深剖面,通过远参考等去噪处理方法以及Rhoplus理论对数据拼接的研究,保证了数据质量的可靠性,并通过选择合适的反演方法得到了研究区深部的电性结构分布。论文介绍了研究区的地层、岩浆岩分布、主要断层、构造演化及矿产分布,分析了典型矿产成矿年龄及其与岩浆岩的对应关系并总结其分布规律。对横跨摩天岭地块的大地电磁二维反演剖面进行了解释。以深部电性结构为依据,结合相关地质资料,根据深部电性结构与岩浆、矿产分布的时空关系,推测岩浆深部来源与运移通道,探讨多金属矿产的深部物质来源与运移情况,为寻找隐伏矿体及远景找矿提供依据。榆中-剑阁大地电磁测深剖面揭示了摩天岭地块南北向的深部电性结构,摩天岭构造带为壳高-幔低阻结构,在地壳以下存在一明显的低阻椭圆囊状结构,与下部连通至岩石圈底界面的低阻柱状体形成低阻地幔柱结构,构成岩石圈以下软流圈中岩浆向上运移的通道,在低阻椭圆囊状体中形成部分熔融的岩浆囊。岩浆囊南北两端上拱,与上部连接至地表的低阻带连接形成逆冲-走滑花状构造,分别在龙门山断裂带与勉略缝合带形成岩浆上涌的通道,且沿北端上涌作用比南端强。松潘-汉中大地电磁测深剖面揭示了摩天岭地块东西向的深部电性结构,电性结构显示深部存在与南北向榆中-剑阁剖面类似的壳高-幔低阻结构,对应摩天岭地块下岩浆囊东西向的分布特征,岩浆向西运移分别在刘家坪及雪宝顶附近形成向上运移的通道。在这些岩浆上涌的通道上部,地表分布的小型岩浆岩脉与金等多金属矿产分布关系密切。论文在研究中对研究区电性结构有其它一些认识与探讨:通过对龙门山北段电性结构与南段的对比,认为龙门山构造带横向结构上存在不均匀性;西秦岭中部存在一连通壳幔的低阻带,与其他相关研究成果对比,推测西秦岭造山带中部存在一大型壳幔低阻岩浆通道,地表广泛分布的大型花岗岩与这一岩浆通道具有一致性,可能为这一岩浆通道的产物。根据地表地质构造背景及金等多金属矿床的地质特征综合分析,在摩天岭地区岩浆上涌通道上部,地壳中低阻带内沿着大型脆性、脆韧性滑脱剪切带(断层)中发育的印支-燕山期小型浅成、超浅成中酸性岩株、岩枝特别是中酸性小型岩脉与金等多金属成矿关系密切,是形成金等多金属矿床最有希望的地段和最主要的找矿标志,并进一步提出摩天岭地块及邻区的有利成矿带,为隐伏矿体勘探及远景找矿提供依据。
[Abstract]:Motenlin is located in Gansu and Sichuan provinces adjacent areas, the structure is located in the northwestern margin of the Yangtze craton, northeast Ganzi tectonic belt of Songpan, north of the West Qinling Mountains orogenic belt. Polymetallic mineral resources in Motianling region rich in mineral mining, but mainly concentrated in the surface and shallow buried mineral exploration degree is low, the existing reserves of mineral resources can not to meet the requirements of economic and social development, the main reason is the lack of the deep tectonic and metallogenic source research. Magnetotelluric sounding to earth natural electromagnetic field source, through broadband magnetotelluric and long period earth electric magnetic deep combination, can effectively detect the crust and the upper mantle of the deep electrical structure characteristics, to provide the earth the physical basis material source and migration of deep research area. Based on the deep geological survey project in Longmen mountain tectonic belt, use across the North-South Yuzhong Motianling massif in Jiange And things to the Songpan - Hanzhoung two magnetotelluric sounding profiles, by far reference denoising method and Rhoplus theory to study on data registration, to ensure the reliability of data quality, and by selecting the appropriate retrieval method of electrical structure distribution of deep research area is obtained. This paper introduces the study area formation, magmatite distribution, main faults, tectonic evolution and distribution of mineral resources, analyzes the corresponding relation between the typical mineral metallogenic age and magmatite and summarize its distribution. In the section of two-dimensional magnetotelluric inversion across motenlin plots were explained. The deep electric structure as the basis, combined with the related geological data, according to the deep Department of electrical structure and magma, relationship between time and space distribution of mineral, that deep source magma and migration channels, explore Polymetallic Mine deep source and migration, to search for concealed ore bodies And provide the basis for ore prospecting. Yuzhong - Jiange magnetotelluric profile reveals Ferris Ling plots to the north and South deep electric structure, Motianling tectonic belt is the shell high mantle low resistivity structure, has low resistance elliptic cystic structure obviously in the crust, and the lower part connected to a low resistance column of lithosphere the bottom interface form a low resistivity mantle plume structure formed under lithosphere asthenosphere magma migration channels formed by partial melting of the magma in the low resistivity cystidium. Elliptical magma on the north and south ends of the arch, connected to form into a thrusting strike slip flower structure and connected to the upper surface of low resistivity belt, belt formed respectively upwelling of magma channels and MIANLUE suture zone in the Longmen mountain fault, and along the northern tip of strong upwelling than. Songpan - Hanzhoung magnetotelluric profile reveals the Ferris Ling plots things to the deep electrical structure, electrical structure display The presence of North and south to the Yuzhong Jiange profile similar shell high mantle low resistivity structure, distribution of magma East-West corresponding Motianling massif, magmatic westward migration respectively in liujiaping and xubaoding formed near the migration channel. The upper channel in the upwelling of magma, small magmatite surface veins the distribution of gold and polymetallic mineral distribution closely. The discussion and some other knowledge of electrical structure in the study area in the study: through the comparison of the northern part of the Longmen mountains and the southern section of the electrical structure, that the Longmen mountain tectonic belt transverse structure is uneven; low resistance connected with a crust mantle west central Qinling Mountains, compared with other relevant research results, that the western Qinling Mountains orogenic belt of the existence of a large low resistivity crust mantle magma channel, large granite surface is widely distributed and the magma channel is consistent, it may be A product of magma channel. According to the comprehensive analysis of geological background and geological characteristics of surface gold polymetallic deposit, the magma of Motianling region upwelling upper channel, crustal low resistivity zone along the large brittle, brittle ductile decollement shear zone (fault) in the development of the Indosinian Yanshan small hypabyssal ultrahypabyssal. In acidic rock strains, especially in acidic rock branches of small dikes and gold polymetallic metallogenic prospecting is closely, formation of gold polymetallic deposits in the most promising area and the main symbol, and further puts forward the favorable metallogenic Motianling massif and its vicinities zone, provide the basis for exploration and Prospect of orebody concealed ore prospecting.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.3

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