| Metal minerals,especially the key metals,have become the strategic and key mineral resources that the world's major economies contend for.The middle and lower reaches of the Yangtze River is an important Fe-Cu-Au polymetallic metallogenic belt in China.From south to north,there are seven ore-concentrated areas in southeastern Hubei province,including Jiurui,Anqing,Luzong,Tongling,Ningwu and Ningzhen.DayeYangxin iron-copper polymetallic metallogenic belt is the main ore concentration area in southeast Hubei province,which concentrates several important iron-rich copper deposits.Gravity and magnetic data and other geophysical methods used in metallogenic prediction and prospecting prediction,have been widely applied in five ore concentration areas of the metallogenic belt including Jiurui,Anqing,Luzong,Tongling,and Ning Wu,and achieved good application results.The successful application in Luzong and Tongling mineralization zone,has proved that give integrated geophysical methods(mainly with gravity and magnetic)provide a good demonstration in the application of this study,which is important technical way for exploring breakthrough of deep prospecting in the ore concentration area.Based on the previous researches on regional geology and ore deposit of the ore concentration area,adopting advanced technology for data processing and interpretation,satellite magnetic and gravity and magnetic data were analyzed.Moreover,the spatial distribution information of faults and contact zones affecting the formation and placement of lithospheric structures,deep and large faults,ore-controlling rock bodies and orebodies(beds)in the whole ore-concentrated area of southeast Hubei are extracted.The regional structure,magma source and other attributes of the study were reorganized.These works are of great significance to the study of deep metallogenic background,basic geological investigation and deep ore prospecting in the whole southeastern Hubei ore concentrated area.In this paper,the geological situation and regional geophysical background of the ore-concentrated area in southeastern Hubei are analyzed on the basis of systematic collection and arrangement of previous scientific research and exploration results in this area.By using satellite gravity and magnetic data,the surrounding tectonic and lithosphere lithologic characteristics of metallogenic belt were to interpreted,that the lithospheric magnetic anomalies of ore concentration area in the middle and lower reaches of the Yangtze river related to regional magmatic activity.The large and medium-sized metal deposits and volcanic-intrusive rocks in the ore concentration area in southeast Hubei province are distributed in the mantle uplift belt of “Echeng-Huangshi-Jiujiang”,and the deep magmatic activities are controlled by the lithospheric structures such as the Qinling-Dabie orogenic belt,the Tanlu fault and the Xiangfan-Guangji fault zone.The main structures in the area occurred in the Indosinian and Yanshanian periods,and the Yanshanian movement is the dominant tectonic movement leading to fault-magmatic activity and mineralization in this area.Based on the analysis of regional gravity and magnetic anomalies,it is considered that the main rock mass regions related to mineralization in the southeastern Hubei ore concentration area have different gravity and magnetic anomaly backgrounds,which indicates that they have different deep geological and structural backgrounds.One of the emphases of this paper is to study the relationship between magmatic rocks and deep structures.By using satellite gravity and magnetic anomalies inversion,3D structure of density and magnetic susceptibility of lithosphere in the ore concentration area and the surrounding area were obtained.According to the results of density distribution,in the presence of slippage between layers of the lithosphere and broken and background,squeezed situation of the earth's crust in the ore concentration area is relatively common,which is formed by indosinian movement approximately parallel double fold and development thrust faults since yanshan period;so that the main fault structures(e.g.,Xiangfan-Guangji fault)failed to become the late mantle-derived magma massive assault on the main channel,and the ore concentration area southeast of Hubei yanshanian magmatic activity in the process of uneven deep source material.These are confirmed by the magnetic susceptibility distribution of the Earth's crust.Based on the results of magnetic inversion,it is considered that the magmatic materials forming the Echeng,Tieshan and Jinshandian intrusions mainly come from the deep magma chamber in the north of the mining area.The magma materials of Lingxiang,Yinzu,Yangxin and Jinniu volcanic basin are mainly derived from the magma chamber under the Jinniu volcanic basin in the north of the mining area,which is blocked by a block with high density,high resistivity and low magnetism in the middle crust.Different magma sources may be one of the important reasons for the different metallogenic types around these rocks.Another focus of this paper is to study regional structures and magmatic rock activities and metallogenic relationships.Through the use of continuation,reducing to the pole,derivation,wavelet multi-scale decomposition,linear signal extraction technique,etc.,the characteristics of mineral zones and gravity abnormalities are analyzed,and the weight magnetic relationship between abnormalities and magmatic rocks and structures are further explored.The main fault structure of the mineral area is repeated,and it pointe out that there may be other utracrustal fault in the zone,and the deep fault in the surface manifestation is a multi-set parallel structure.The deployment range of the deep space of the area was set by a comprehensive analysis.On this basis,three-dimensional magnetization and density inversion is performed by using the measuring area 1: 50,000 aeromagnetic data and 1:100,000 gravity data.It is the first time to use the magnetic modulus inversion technique to carry out three-dimensional magnetic anomaly inversion.According to the inversion results,the spatial distribution characteristics of deep magma and possible magma passages were inflated.According to density and magnetization distribution,it was speculated that the rock mass and the fault constituents explained in this paper were closely related.In addition,the relationship between depth structure and rock mass in mineral area is confirmed by comparing the existing electromagnetic detection profile.Combined with deep research results in the mineral area,comprehensive geophysical research and prospecting predictions were carried out in the two typical regions of Echeng-Tieshan area and Jinniu volcanic rock basins.Through the comprehensive research of Echeng-Tieshan area,the rock mass and peripheral geology in the Tieshan area have characteristics of medium-low density and high magnetic.The model of prospecting prediction is established.Based on this,three favorable prospecting target areas are inferred: deep area in the southern margin of Chengchao iron mine(1.5km-2 km),deep area in the Chensheng-Mayangnao forestry centre(less than 2 km),and deep area in the southern margin of Tieshan rock mass to Huandiqiao(less than 2 km).Based on the analysis and calculation of geological,geophysical data of Jinniu volcano basins,the base interface of the volcanic basin is obtained.Several buried craters were delineated,and the junction of NE and NWW structures and the craters was determined as the favorable prospecting target.This paper adopts the research idea of “lithospheric structure ? magmatic activity? mineral area ? rock mass”.On the basis of the obtained lithosphere structure,the relationship between the fault structure and the magmatic rocks and the deep structure in the ore-concentrated area is systematically sorted out.A new viewpoint on the source of magmatic material in different mineral rock is proposed,and the favorable target areas for prospecting in the deep of Echeng-Tieshan area and Jinniu volcanic basin are put forward by combination with the prospecting practice. |
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