Geochemical Characteristics,Genesis of Concealed Cu-rich Ore Body in the Jinchuan Deposit,Northwestern China,and Its Prospecting

The Jinchuan deposit is hosted by the olivine-rich ultramafic rock body, which is the thirdlargest magmatic sulfide Ni-Cu deposit in the world currently being exploited. Seeking new relaying resources in the deep and the border of the deposit becomes more and more important. The ore body, ore and geochemistry characteristics of the concealed Cu-rich ore body are researched. Through spatial analysis and comparison with the neighboring II1 main ore body, the mineralization rule of the concealed Cu-rich ore body is summed up. It is also implied that Cu-rich magma may exist between Nirich magma and ore pulp during liquation differentiation in deep-stage chambers, which derives from deep-mantle Hi-MgO basalt magma. It is concluded that the type of ore body has features of both magmatic liquation and late reconstruction action. It has experienced three stages： deep liquation and pulsatory injection of the Cu- and PPGE-rich magma, concentration of tectonic activation, and the later magma hydrothermal superimposition. In addition, the Pb and S isotopes indicate the magma of I6 concealed Cu-rich ore body originates predominantly from mantle; however, it is interfused by minute crust material. Finally, it is inferred that the genesis of the Cu-Ni sulfide deposit is complex and diverse, and the prospect of seeking new deep ore bodies within similar deposits is promising, especially Cu-rich ore bodies.

Diagenesis-Mineralization and Ore Prospecting of the Yangla Copper Deposit, Yunnan Province, Southwest China

The large-scale Yangla copper deposit, located in the central part of the Sanjiang Tethys polymetallic belt, is structurally controlled by the Jinsha River Fault and Yangla Fault. This deposit consists of seven ore blocks, including the Beiwu, Nilv, Jiangbian, Linong, Lunong, Tongjige and Jiaren. The Cu metal prospective reserves of the Yangla deposit are above 1 million tons. There are widely distributed Indosinian granodiorite and also many gabbro-diabase dikes and few quartz porphyries exposed in the Yangla ore district. The ore-hosting rocks are diopsode-garnet skarn, sericitie sandy slate and metamorphic quartz sandstone of the first member of the Devonian Linong Formation. Ore bodies occur as layered, stratoid, lenticular and veined shapes, and are strictly controlled by rocks, strata and structures.

Magnetic Method Surveying and Its Application for the Concealed Ore-Bodies Prospecting of Laba Porphyry Molybdenum Ore Field in Shangri-La, Northwestern Yunnan Province, China

Recently, a number of large molybdenum (-copper) deposits have been discovered successively in the Laba area, Shangri-La county, northwestern Yunnan province. The investigation confirmed that there is a superlarge porphyry-skarn hydrothermal vein type molybdenum-polymetallic- metallogenic system with the total prediction reservoir of more than 150 mt molybdenum. The porphyry intrusions contributed to the mineralization closely, the superficial little vein molybdenum (-copper, lead, silver) ore-bodies are usually located in faults and fractures, and the deep porphyry type ore-bodies occurred in the granodiorite porphyries, the skarn type ore-bodies occurred in the contact zone intrused into Triassic limestone or Permian basalts. Laba ore block is a new exploration area with great prospecting potential. In order to reduce the target area and guide the further exploration work, the magnetic method measurement about 3.3 square kilometres was carried out in the ore field. This paper presents an application of analyzing the horizontal and vertical derivative, using Fast Fourier Transform (FFT) filter (FFT high-pass, low-pass, cosine roll-off, suscepbility), calculated spectra frequency energy to predict the depth and intensity of the apparent remanence magnetization of source (Hilbert). The calculated results and magnetic anomalous show that the remanence anomaly is caused by the intrusions into the Triassic limestone and Permian basalts with small anomalies, and the depth of located source is not great. We have identified a number of positions to the three drilled well, the drilled result specify interpretation with very high accuracy. The magnetic method is helpful to identify porphyry mineralization, and judge the shape and depth of the concealed ore-bearing intrusive bodies under the similar geological condition.

Analysis on Prospecting Potential of Tungsten Polymetallic Ore in Haergeng of Gonghe County, Qinghai Province

The discovery of Gonghe County Haergeng tungsten polymetallic deposit is one of the most important tungsten deposits discovered in Qinghai Province in recent years.It has important theoretical and practicalsignificance.1 Regional geological background The research area lies in the northwest edge of

Geological Characteristics and Prospecting Criteria of Senji Molybdenum Ore Body in Urad Houqi, Inner Mongolia, China

Geological Characteristics and Prospecting Indicators of Senji Molybdenum Ore Body in Urad Houqi, Inner Mongolia Based on geological mapping, soil geochemical survey, surface trough exploration and deep drilling verification and control, the Senji Molybdenum deposit was discovered. Geological characteristics of the molybdenum ore body are described. The host lithology of molybdenum ore body is mainly in the cataclastic carbonated black plagioclase gneiss of the second rock member of the Paleoproterozoic Baoyintu Group, followed by Early Carboniferous monzogranite. The genetic type of the deposit is preliminarily deduced to be a hydrothermal filling vein-type molybdenum deposit. The significance of this paper is to summarize the prospecting marks of the molybdenum ore body in this area, so as to further guide the exploration work in this area, and at the same time provide a useful reference for the exploration work of similar deposits in other areas.

Geological Characteristics and Regional Prospecting Model of Wulanchongji Gold Orebody, Alxa Youqi, Inner Mongolia, China

Five gold deposits (mineralization) were found in the study area by means of geological mapping, soil geochemical survey and trough exploration engineering. The ore-bearing lithology is mainly metamorphic feldspar sandstone of the Upper Carboniferous Benbatu Formation, and the gold (mineralization) body is controlled by both structural factors and stratigraphic factors of the Upper Carboniferous Benbatu Formation. The genetic type is preliminary concluded to be volcanic hydrothermal type, and the metallogenic age is late Variscan. In this paper, by studying the geological characteristics and metallogenic geological conditions of the gold orebody in the area, a regional prospecting model has been established, which is of great significance to better guide the prospecting work of similar gold deposits in the area and the region.

Approaches to location prognosis of concealed ore deposits (bodies) of productive mines

This paper demonstrates the channels and methods for location prognosis of concealed ore deposits (bodies) in the deep seated and surrounding districts of productive mines in accordance with their special features. The system frame map is built, from quick exploration in the field to the rapid building of a model indoors. The main research points of location prognosis are also discussed in the paper, which include: 1) integrating the location with the surrounding geological areas, microscopic with macroscopic; 2) analyzing and synthesizing all geological information of different levels, depths and aspects; 3) laying stress on mineralization series; 4) paying attention to the study of the distribution law of ore bodies; 5) introducing the theory of nonlinear dynamics of ore forming processes to ordinary static prognosis; 6) the necessity of the geophysical me thod in recovering information of concealed ore bodies; 7) the combination of all kinds of geology, geophysics, geochemistry and remote sensing methods.

Discovery of ferromanganese crust boundary and its genetic and ore prospecting significance

Evidences for the existence of ferromanganese crust boundary were found for the first time during the survey of the “DA YANG YI HAO” Vessel 2003. Some typical characteristics of the boundary are summarized and the significances of the finding of the boundary are included in the genesis discussion. Ore prospecting and assessment of the crust resources are described in this paper. The morphologic and extending characteristics of the crust boundary led to the recognition of two types of crust boundary： interpenetration crust boundary and closed crust boundary. According to the distribution and types of the crust, however, the boundaries are classified into three types： the boundary between ferromanganese crust and detrital sediment, the boundary between tabular crust and seamount nodules, and the boundary between tabular crust and rudaceous crust. This study revealed that the boundary between tabular crust and nodules was not formed under different regional environments but formed under different nucleation potential barriers between different initial growth （nucleation and germination） processes and between solid rocks and loose sediments. The rudaceous crusts are controlled spatially by fracture zones and the crusts＇ boundaries are controlled by the seamount structure and landform. The discovery of the crust boundaries reveals the crust＇s ‘negative growth’ phenomena （especially for some seamount nodules）. The boundary investigation can be helpful in identifying the existence of tabular crust covered by detrital sediments and in calculating the area covered by the crust. The resource calculation error and the resource quality as well as resource exploration degree can be assessed through the survey of crust boundary.

Joint Application of Geostatistics and Multifractals for Decision-Making System of Ore Prospection in a Mineral Deposit

The strategy of ore prospection is made on the basis of raw exploratory data which are the products of coupled geological processes and random natural reformation. This decision-making system is extraordinary risky and needs to be supported by various statistical sciences. In this paper, geostatistics and multifractals are jointly employed to delineate the complexity of mineralization and to provide important guidelines for future ore prospecting. The geostatistical analysis indicates the mineralization in granite domain is more homogenous than that in wallrocks, and the exploratory spacing in these two lithological units should be different when taking into consideration the range of variogram. The multifractal analysis shows the spatial variation of mineralization homogeneity. The mineralization in the southwest of this region is much more heterogeneous than that in the granite. The schemes of borehole design are specified based on the combination of abovementioned analytical results. The joint application of geostatistics and multifractal proposed in this study can excavate the exploratory data and output mathematic models in an intuitive and quantitative way, assisting in decision-making and risk avoidance of mining industry.

Geochronology,Petrology and Geochemistry of Xingdi No.3 Mafic-Ultramafic Intrusions in the Northeastern Tarim Craton,NW China

The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low 143Nd/144Nd ratios（from 0.511183 to 0.511793） and high initial 87Sr/86Sr ratios（from 0.7051 to 0.7113）. The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area.

Research achievements of the Qinghai-Tibet Plateau based on 60 years of aeromagnetic surveys

The Qinghai-Tibet Plateau(also referred to as the Plateau)has long received much attention from the community of geoscience due to its unique geographical location and rich mineral resources.This paper reviews the aeromagnetic surveys in the Plateau in the past 60 years and summarizes relevant research achievements,which mainly include the followings.(1)The boundaries between the Plateau and its surrounding regions have been clarified.In detail,its western boundary is restricted by West Kunlun-Altyn Tagh arc-shaped magnetic anomaly zone forming due to the arc-shaped connection of the Altyn Tagh and Kangxiwa faults and its eastern boundary consists of the boundaries among different magnetic fields along the Longnan(Wudu)-Kangding Fault.Meanwhile,the fault on the northern margin of the Northern Qilian Mountains serves as its northern boundary.(2)The Plateau is mainly composed of four orogens that were stitched together,namely East Kunlun-Qilian,Hoh-Xil-Songpan,Chamdo-Southwestern Sanjiang(Nujiang,Lancang,and Jinsha rivers in southeastern China),and Gangdese-Himalaya orogens.(3)The basement of the Plateau is dominated by weakly magnetic Proterozoic metamorphic rocks and lacks strongly magnetic Archean crystalline basement of stable continents such as the Tarim and Sichuan blocks.Therefore,it exhibits the characteristics of unstable orogenic basement.(4)The Yarlung-Zangbo suture zone forming due to continent-continent collisions since the Cenozoic shows double aeromagnetic anomaly zones.Therefore,it can be inferred that the Yarlung-Zangbo suture zone formed from the Indian Plate subducting towards and colliding with the Eurasian Plate twice.(5)A huge negative aeromagnetic anomaly in nearly SN trending has been discovered in the middle part of the Plateau,indicating a giant deep thermal-tectonic zone.(6)A dual-layer magnetic structure has been revealed in the Plateau.It consists of shallow magnetic anomaly zones in nearly EW and NW trending and deep magnetic anomaly zones in nearly SN trending.They overlap vertically and cross horizontally,showing the flyover-type geological structure of the Plateau.(7)A group of NW-trending faults occur in eastern Tibet,which is intersected rather than connected by the nearly EW trending that develop in middle-west Tibet.(8)As for the central uplift zone that occurs through the Qiangtang Basin,its metamorphic basement tends to gradually descend from west to east,showing the form of steps.The Qiangtang Basin is divided into the northern and southern part by the central uplift zone in it.The basement in the Qiangtang Basin is deep in the north and west and shallow in the south and west.The basement in the northern Qiangtang Basin is deep and relatively stable and thus is more favorable for the generation and preservation of oil and gas.Up to now,19 favorable tectonic regions of oil and gas have been determined in the Qiangtang Basin.(9)A total of 21 prospecting areas of mineral resources have been delineated and thousands of ore-bearing(or mineralization)anomalies have been discovered.Additionally,the formation and uplift mechanism of the Plateau are briefly discussed in this paper.

Classification,Minerogenic Models and Prospecting of Realgar/Orpiment Deposits in China

China's realgar/orpiment deposits may be classified into three types, the stratabound, hot-water sedimentary and hydrothermal, according to their mineralizing processes, geological occurrences, tectonic and geochemical features. The three types may be further distinguished into seven subtypes, namely, the Xiaguan, Shuiluo, Jiepaiyu, Songpan, Shixia, Wangzhuang and Ninghshan ones. On this basis three minerogenic models are established, and based on studies of their geochemistry and minerogenic mechanisms the prerequisites for prospecting for these types of deposits are given in the paper.

Geospatial Mapping of Singhbhum Shear Zone (SSZ) with Respect to Mineral Prospecting

Singhbhum Shear Zone is a highly mineralized zone having variety of minerals, predominantly those of uranium, copper and some sulphide minerals. From Remote Sensing data it is possible to decipher the regional lithology, tectonic fabric and also the geomorphic details of a terrain which aid precisely in targeting of metals and minerals. Mapping of mineralized zones can be done using Geospatial Technology in a GIS platform. The present study includes creation of various maps like lithological map, geomorphological map, contours and slope map using satellite data like IRS LISSIV and ASTER DEM which can be used to interprete and correlate the various mineral prospective zones in the study area. Even the alterations of the prevalent mineral zones can be mapped for further utilization strategies. The present work is based on the investigations being carried under ISROSAC Respond Project (Dept. of Space, Govt. of India SAC Code: OGP62, ISRO Code: 10/4/556).

Age and Genesis of the Laodaizhanggou Pb-Zn-Ag Deposit in the Fudian Ore Field,Southern North China Craton:Implications for Regional Mineral Prospecting

The Fudian ore field in the southern North China Craton hosts the giant Donggou porphyry Mo deposit and several Pb-Zn-Ag vein deposits. Ore genesis of the Pb-Zn-Ag deposits and their relationships with the Donggou porphyry-related system are still controversial, which further restricts the regional prospecting and exploration. The Laodaizhanggou Pb-Zn-Ag deposit in the northwest of the ore field was focused in this study, to investigate its ore-forming age and genesis, and further to explore the implications for regional prospecting of Pb-Zn-Ag and Mo. The Pb-Zn-Ag veins at Laodaizhanggou are structurally controlled by the east-striking fault zones transecting the host volcanic rocks of Proterozoic Xiong’er Group. Field observations and textural relationships indicate that there are four paragenetic stages during ore-forming process, including the quartz-pyrite veins(stage I), siderite-polymetallic sulfide veins(stage II), ankerite-polymetallic sulfide veins(stage III), and quartz-calcite veins(stage IV). Ore-related sericite 40 Ar/39 Ar dating shows that the Pb-Zn-Ag mineralization at Laodaizhanggou was formed at 124.7±1.2 Ma. Carbonate minerals(siderite, ankerite, and calcite) have δ13 CPDB values of-9.1‰ to-3.9‰ and δ18 OSMOW of 12.1‰ to 15.6‰, corresponding to calculated values for the ore fluids of-8.0‰ to-2.8‰ and 4.9‰ to 10.1‰, respectively. These isotope values are in accordance with those of magmatic fluids. Sulfide minerals at Laodaizhanggou have δ34 S values of 5.3‰ to 10.1‰, and galena separates have 206 Pb/204 Pb ratios of 17.380 to 17.458, 207 Pb/204 Pb ratios of 15.459 to 15.485, and 208 Pb/204 Pb ratios of 38.274 to 38.370. Both S and Pb isotope data of Laodaizhanggou are consistent with those of the Donggou porphyry Mo deposit and distal Sanyuangou and Wangpingxigou Pb-Zn-Ag deposits, suggesting they share a similar magmatic origin. However, the Laodaizhanggou deposit was not the distal product of the giant Donggou porphyry-related magmatic-hydrothermal system, as the former is about 7 Ma older than the latter. The ore-forming age of Laodaizhanggou is consistent with that of the phase 1 magmatism of Taishanmiao batholith, indicating the Laodaizhanggou deposit is genetically related to ca. 125 Ma magmatism in the area. Combined the geochronological and geochemical data on Laodaizhanggou and the regional geological setting, we propose that the fracture systems in the northeast of the Taishanmiao batholith are potential sites for prospecting Pb-Zn-Ag deposit and the deep part among Laodaizhanggou, Xizaogou, and Liezishan is a target for prospecting porphyry Mo deposit.

A Discussion on the Geochemical Characteristics of Stream Sediments and Ore - Prospecting Orientation in Weixing - Anquan Area of Heilongjiang Province

The Luming molybdenum deposit is located in Weixing-Anquan area of Heilongjiang Province, where stream sediments are well - developed. This paper introduces the popular statistical method which investigates the relationship between geochemical character - istics of stream sediments and mineralization. Some conclusions have been reached : 1) Mo is most likely to form large deposits;Au may form ore deposits, but the size will not be large;2) Mo and Sb, Cu, Pb, Zn. W belong to the same factor. and Mo has experienced multi-period mineralization;Au. Ag and As belong to the same factor;and 3) the authors chose 4 mineralization prospective areas to study stream sediment anomaly and found a new Mo orebody, which suggests that this area has good oresearch prospects of Mo deposits.

Exploration and research progress on ion-adsorption type REE deposit in South China

Since 2011,certain advances have been made through the resource investigation,metallogenesis research,mining supervision and environmental protection of ion-adsorption type rare earth element (REE) deposit in South China.Firstly,some progress has been made in REE prospecting in Jiangxi,Guangdong,Guangxi and Yunnan.REE deposits are not only found within the weathering crusts of granites and felsic volcanic rocks,but also within the weathering crusts of epimetamorphic rocks and basic magmatic rocks.Secondly,the methods of exploration,delineating ore bodies and calculation of reserves have been improved,which intuitively reflect the thickness,REE composition and value of weathering crust.Thirdly,the relationship between REEs and weathering degree and the rule of distribution,migration and enrichment of REEs in the weathering profile was summarized through the analysis of big data,which can predict the metallogenetic horizon of REEs.Fourthly,a method for quick,accurate and dynamic investigation of the REE deposit has been established by using high resolution remote sensing technology.Finally,the relation between the production status of REE mines and water pollution has been revealed based on long-term hydrochemical monitoring data of rivers and wells in mines and surrounding areas.

Analysis of prospecting polymetallic metallogenic belts by comprehensive geophysical method

This paper is based on the analysis and research on the silver-lead-zinc polymetallic ore in New Ballyhoo Banner in southern Manzhouli of Inner Mongolia.Because metal mineralization brings rock formations,the geophysical features such as low resistivity,high polarization rate and uneven distribution of magnetization,the comprehensive geophysical methods are adopted including high-precision magnetic measurement,high-power induced polarization,IP field middle gradient and controlled source audio-frequency magnetotellurics.In the survey work of multi-metal ore deposits,from surface sweeping to single point measurement,and from single point to section going deeper layer by layer,the resolution of measurement is continuously improved,and various geophysical methods support and complement each other,so explorers can successfully predict the direction,scale and volume of the metallogenic belts in conjunction with geochemical exploration,geological survey and drilling.It has provided a strong basis for completing the exploration task of predicting the reserve volume of ore bodies.The research conclusions of this exploration case have thus a high reference value in the same type of exploration work.

PROSPECTING FOR LARGE TRIHYDROXY BAUXITE DEPOSITS IN CHINA: THINKING AND PERSPECTIVE

Large trihydroxy bauxite deposit was once considered unavailable in China.With the prospecting think-ing of diwa theory,the author has drawn a contrary conclusion.From the view of the law of progression with transformation between mobile and stable regions and the metallogenic specialization of tectonic elements,he reveals the principal reason why the known bauxite deposits in China are mostly of monohydroxide type,and acquires the way of searching for trihydroxide bauxite deposits.He considers that the residual-mobility period of the diwa stage in the crustal development in South China pocesses-tectonic conditions favourable to the formation of bauxite deposits of this type.He believes that the Cenozoic structural sublayer of the residual-mobility period of the diwa stage developed on the carbonate rock of the Paleozoic platformal structural layer is the preferrential target of prospecting.With this thinking and many years of efforts,we have gained prelimi-nary achievements and have discovered Guigang-type latee-ritic trihydroxied bauxite deposits in Guangxi.In future,by extension and analogy of the thinking,we are likely to find large,high-grade bauxite deposits in its vicinity and to discover weathering-type bauxite deposits with other parent rocks.

PORPHYRY COPPER (-MOLYBDENUM-GOLD) DEPOSIT PROSPECTIVITY IN ZHASHUI-SHANYANG MINERALIZATION BELT,QINLING MT., NW CHINA

The paper focuses on the geological setting, forrning environment, petrochemistry, isotope, etc. of the Yangshanian intermediate-acid porphyry intrusion in ZhashuiShanyang mineralization belt. The alteration type and zone of the intrusion and its host rocks have been studied, and the characteristics of the known copper (-molybdenum-gold) mineralization occurrence have been investigated. Hence the metallogenetic factors and ore prospectivity have been evaluated by comprehensive study of the metallogenic geology and correlation with the rnega-porphyry copper(-molybdenum) deposits in the world.