1) The formation of large-scale gold belt must have rich ore sources; Extremely favorable tectonic environment; Large-scale, long-term active heat sources and physical and chemical conditions conducive to precipitation. The formation of super-large and medium-sized gold deposits in China has obvious epigenetic properties, and the ore-forming materials mainly come from source beds (rocks). Generally speaking, the larger the source bed (rock) is, the more favorable it is for the formation of super-large gold deposits. Such as the pre-Archean primitive continental crust; Archean metamorphic greenstone formation; Intermediate-basic volcanic rocks are formed in the terrigenous clastic rock series of Proterozoic and Archean Proterozoic basins or depressions; After Paleozoic, volcanic rocks, subvolcanic rocks, carbonaceous mudstone series deposits and intrusive rocks can all form large source beds (rocks). Archean and some metamorphic intermediate-basic volcanic rocks generally have high gold-bearing background values and are ideal source beds. Therefore, these old strata distribution areas are favorable areas for finding large-scale gold deposits, and the above source beds (rocks) have high gold-bearing background values, which is a necessary condition for determining the regional prospecting direction.
2) The distribution of regional minerals is controlled by large-scale fault zone, syngenetic fault zone, ductile-brittle ductile shear zone and giant fault intersection zone. These fault zones mainly include Habato-Xilamulun fault zone in Ilya, Kangxiwa-Shangnan-Rongcheng fault zone, Congras-Lancangjiang fault zone, Yarlung Zangbo river fault zone and Taitung longitudinal valley fault zone, which belong to plate combination zone. The crustal splicing zones are Erqis-Delbays main fault zone, Karamay-Erlian fault zone, Dalabute fault zone, North Qilian fault zone, Shangnan-Shangcheng fault zone, South Qilian fault zone, Kangxiwa-Shangnan-Rongcheng fault zone, Jinshajiang-Honghe fault zone, Bangongcuo-Nujiang fault zone, Yichun-Liuzhou fault zone, tengxian-Beihai fault zone and Shaoxing-Pingxiang fault zone. In addition, faults in the northern margin of North China Platform, Jining-Lingyuan fault, Altun fault, Longshoushan-Gushi fault, southern margin of North Qilian Mountain, Daofu-Kangding fault, Youjiang fault, Daxinganling-Taihang Mountain fault, Yilan-Lan Shu fault, Tanlu fault, Sihui-Wuchuan fault and Lishui-Lianhuashan fault have great influence on China gold mine. For example, Kangbao-Weichang-Chifeng-Kaiyuan fault and Zhangjiakou-Chengde-Pingquan-Ningcheng-Beipiao deep fault in the northern margin of North China block; Xiaguan-Hu Aishu fault and Shangnan-Xixia fault in western Henan; Sanjiang fault zone in western Yunnan is a favorable area for finding large gold deposits.
3) As far as super-large deposits in China are concerned, they are mainly controlled by large structures. According to the statistics of Zhai Yusheng et al. (1997) on the super-large deposits (gold-bearing deposits) in China, these structures mainly include rift and aulacogen; Deep faults in and around the ancient land; Ductile shear zone of ancient continental greenstone belt; Continental fault-fold-magmatic composite structure active continental margin tectonic magmatic belt; Continental marginal basins and continental shelf slope belts; Granite dome of continental crust; Volcanic mechanism of continental volcanic belt; Inland and continental margin sedimentary basins; Brittle deformation structural zone in shallow continental crust.
4) Large-scale ore-accumulating structures often have the following identification marks: ① Large hydrothermal alteration zones are distributed along structural lines, such as silicification, pyritization, sericitization, argillization, etc. (2) Large hydrothermal deposits are distributed along the structural zone, such as albite, siliceous rocks, iron manganese carbonate, etc. Devonian system in South Qinling; ③ Large-scale thermodynamic metamorphic belt is distributed along the tectonic line; ④ The regional distribution of hydrothermal tectonic belt, hydrothermal vein and igneous vein is linear; ⑤ Geophysical and geochemical linear anomaly zone.
5) When looking for super-large gold deposits in the old metamorphic rock area, we should pay attention to the active zone at the plate edge, the regional large fault zone (such as the Tanlu fault zone), the vicinity of late intrusive deep granite and granodiorite, and the areas where mylonite zones and basic dikes are developed.
6) When looking for super-large gold deposits in the strata after Mesozoic, we should pay attention to the active characteristics and distribution range of intermediate-basic volcanic rocks and subvolcanic rocks in various depressions and basins, which mostly belong to the platform margin and intra-platform active zone in geotectonics.
7) The boundary areas and long-term uplift areas of different structural units are favorable areas for finding large-scale gold deposits. For example, the northern margin of North China Platform, the periphery of Junggar Platform and Tarim Platform, the northwest and southwest margins of Yangtze Platform, the margin of Jiamusi Block and Jiaodong Uplift, Tieling-Jingyu Uplift and Xuefeng Uplift are all favorable areas for finding large-scale gold deposits. (Wei Yongfu et al., 1994).
8) The distribution area of large-scale gold deposits is generally the exposed area of large mylonite zone or large-scale fault zone, with large fracture variation intensity, and fault gouge is often seen in the fault zone, and the width of the fault zone is relatively stable along the strike and dip. The strike and dip of gold mineralization are also relatively stable.
9) Mineralization is the result of crust-mantle interaction, that is, the transfer of material field and energy field. It must be supported by a permanent dynamic thermal environment, and mineralization is often the result of multiple preconcentrations. Therefore, multi-stage tectonic and magmatic thermal events in the area, accompanied by orderly metamorphism, sedimentation and magmatic activity, are necessary conditions for the formation of large-scale deposits. Therefore, tectonic analysis and thermodynamic field research are important methods for metallogenic identification, and we should pay close attention to the superposition and recombination of mineralization.
10) mantle information is an important topic in metallogenic research. The thinning of the crust, the transition zone between mantle uplift and mantle depression, the mantle slope zone, the exposed area of mantle plume, the secondary fault zone and its vicinity of the mantle material influx zone, the development zone of intermediate-basic dikes and the concentration zone of lamprophyre dikes are all areas worthy of attention. Mantle emanation measurement, study on fluid inclusion characteristics, geophysical fields (gravity, magnetism and electricity)
1 1) Large gold deposits are formed by large-scale solution flow and a large number of minerals are precipitated in a small range, so there should be a more suitable physical and chemical environment for precipitation. In addition to the structural conditions, the physical and chemical characteristics of surrounding rock are also very important, such as the nature of surrounding rock, the abundant existence of iron and sulfur, the appearance and characteristics of groundwater, and the plugging of impermeable layer, which will all play an important role (Wei Yongfu et al., 1994).
2. Gold metallogenic prospect area
Many units and individuals have done a lot of work on the division of gold prospect areas. 1994 Pan divided China gold deposit into 45 metallogenic prospect areas, 1993 Institute of Gold Geology of Chinese People's Armed Police Force divided into 43 rock gold deposit prospect areas, 1995 Chen Yuchuan and Wang divided into 465438+.
Main features and work points of important scenic spots (see Section IV for general geological features):
(1) Jiaodong gold metallogenic area
Jiaodong gold deposit concentration area is located in the uplift belt on the edge of ancient block. At present, the accumulated proven rock gold reserves in this area are 9 13.84t and the predicted reserves are 1500t. Mesozoic and Cenozoic basins such as Zhaoye ore belt, northern part of Zhaoping fault in Zhaoye ore belt, Penglai-Qixia ductile shear belt, Mu Ping-Rushan structural belt, Deng Rong-Wendeng structural belt and Laiyang basin.
(2) Liaoyan metallogenic belt
This belt, including inner mongolian axis and Liao Yan Rift Zone, is one of the main gold mineralization areas and an important gold production base in China. There are more than 65,438,000 known rock gold deposits in this area, with accumulated proven reserves of more than 200 tons. The main rock gold deposits in this area are greenstone belt type gold deposits, contact belt type gold deposits occurring inside and outside the intrusive body and gold deposits related to Mesozoic volcanic rocks and subvolcanic rocks, while Dongping and Hougou gold deposits are famous for occurring in alkaline intrusive complexes. The east-west faults such as Kangbao-Chifeng fault, Fengning-Longhua fault, Chongli-Pingquan fault, Miyun-Qinglong fault and the Yanshanian northeast fault structure control the distribution of gold deposits in the area.
Chicheng-Chongli, Nuruhushan, Yuerya-Maojiadian, Xinglong-Qinglong, Fengning-Pingquan, Chaoyang Bay-Honghuagou, Hot Water-Rotor and Jinxi-Jinzhou have further work value.
(3) Xiaoqinling gold metallogenic area
In China, this area is second only to Jiaodong, including Xiaoqinling, Xiong 'er Mountain and Xiaoshan. The accumulated proven reserves in this area exceed 400 tons. More than 60 gold deposits have been discovered in/kloc-0. Famous mineral deposits include Wenyu, Yangzhaiyu, Tongguan, Tongyu, Zhuyu, Jindongcha, Dongchuang, Sifangou, Hu Da, Shanggong, Kangshan-Xingxingyin, Yaogou, Tantou, Qiangmayu and Laoyacha. The gold deposits in this area are mainly regenerated gold deposits in the greenstone belt, and their distribution is controlled by the construction of Archean greenstone belt. Yanshanian magmatic thermal events play a vital role in mineral enrichment. Regional EW-trending fold faults and NE-trending faults are basic ore-controlling structures, and Xiaoshan gold field is mainly controlled by EW-trending and NW-trending structures. The ore-bearing strata are mainly the lower subgroup of Archaean Taihua Group and the volcanic rock series of Yuanguyu Xiongershan Group.
Table 8-5 List of National Gold Exploration Areas
sequential
sequential
sequential
There are more than 65,438+0,000 timely veins in this area. At present, the axis of Laoyacha anticline in Central Asia has been evaluated, and nearly half of other time pulses have not been evaluated. This is the main prospecting direction in this area. The exploration depth in this area is generally 400 ~ 500 meters. According to the comparison of the exposed elevation of existing ore bodies, there is still great prospecting potential in the deep part of this area. Attention should be paid to new types of prospecting work. In Xiong 'ershan area, we should not only pay attention to Taihua Group, but also pay attention to the prospecting work of Xiong 'ershan Group, and also strengthen the geological work on the south slope of Xiong 'ershan Mountain.
(4) The triangle of Hubei, Anhui and Jiangxi (the middle and lower reaches of the Yangtze River)
The gold deposits in this area are mainly associated gold deposits, which is the main concentration area of associated gold deposits in China, accounting for 64% of the national associated gold deposits. Associated gold deposits are mainly distributed in Cu, S, Fe-Cu, Cu, Cu-Mo, Pb-Zn deposits, mainly Cu-S (Au) deposits. In addition, there are rock gold deposits or symbiotic gold deposits in this area, such as Yangjishan, Jilongshan, Jiguanzui, Jinshan, Mashan and Huangshi Laoshan.
Gold deposits are mainly distributed in Qixia, Tongling, Daye, Jiujiang-Ruichang and Wuyuan-Dexing. Maanshan, Maoshan-Tongshan, Zongyang-Huaining, Tongshan-Matou and other places.
The gold deposits in this area are mainly distributed in eastern Hubei, northeastern Jiangxi and Tongling area, which is the focus of further prospecting.
(5) Yunnan-Guizhou-Guangxi Triangle
This area is located in the southwest of Caledonian Mountains in South China and belongs to Youjiang orogenic belt. The main strata exposed in this area are Devonian, Carboniferous, Permian and Triassic, but the magmatic activity in this area is relatively weak. Gold deposits mainly occur in upper Paleozoic-Triassic siltstone, argillaceous rocks and carbonate rocks, which can be divided into: ① fine disseminated gold deposits, such as Zimudang, Gotang, Lannitang and Jinya; ② Yingshi-calcite vein type gold deposit, the typical deposit is Jiaoman, Tian Yang, Guangxi.
Sedimentary rock-type gold deposits are widely distributed in southwest Guizhou and Youjiang areas, especially in southwest Guizhou, and are potential prospecting targets in China. Attention should be paid to the prospecting work in southwest Guizhou, Nanpanjiang-Youjiang, leye county-Bama and Tiandong-Debao areas.
(6) Shanxi-Gansu-Sichuan Golden Triangle Region
It is located at the junction of Shaanxi, Gansu and Sichuan provinces, at the intersection of Longmen-Dabatai fold belt of Yangtze platform, Maogeosyncline orogenic belt of South Qinling and Bayankala Maogeosyncline orogenic belt of Songpan-Ganzi orogenic system.
This area is one of the important gold producing areas in China, and Mesoproterozoic Bikou Group, Silurian Bailongjiang Group (including Maoxian Group), Middle-Upper Triassic carbonaceous and argillaceous clastic rocks, argillaceous rocks and carbonate rocks are important ore-bearing strata. Gold deposits mainly belong to metamorphic clastic rock type, fine disseminated type and placer gold mine. Fengxian-Zhen 'an, Mianninglue, Minjiang River, Longmen Mountain, Bailong River, Wenxian County-Lotus Leaf, Snow Mountain, Shiquan and Ankang have great prospecting prospects. Regional attention should be paid to deep faults such as Lintan-Fengxian, Maqin-Lueyang and Longmenshan, as well as areas with strong magmatic activity in Bailong River and Yuehe fault and Indosinian-Yanshan period.
(7) Guangdong, Guangxi and Qionglai.
Gold mineralization is mainly concentrated in western Guangdong-Hainan and Dayaoshan area in Guangxi. It can be divided into five tectonic metallogenic areas, namely: Dayaoshan metallogenic area, located in Dayaoshan uplift zone; Luoding metallogenic area, located in Luoding depression; Yunkai metallogenic area is located in Yunkai uplift zone; Taishan metallogenic area is located in Zhanxian dome in the southwest of Hainan Island, between Taishan uplift and Huaxian depression.
The gold deposits in this area are mainly distributed in Yunkai Uplift and Dayaoshan Uplift, which are related to Mesoproterozoic Yunkai Group, Yingyangguan Group, Lechangxia Group and Cambrian. They are controlled by the middle sections of Wuchuan-Sihui fault zone and Guangning-Luoding fault zone, located at the junction of Guangzhou upper mantle uplift and Xinyi mantle depression, and there are Huaiji-Fogang and Gaoyao-Huilai east-west faults in the north and south. The gold deposits in the north of Dayaoshan are mainly CAMBRIAN metamorphic clastic rock type gold deposits and granite contact zone type gold deposits. There are mainly the following types of gold deposits in this area: ① Metaclastic rock types, such as Hetai, Pangxidong-Jinshan, Taohua and Gao Feng; (2) metamorphic hydrothermal sedimentary rocks, such as Dagougu, in which gold occurs in albite; ③ hydrothermal sedimentary rock type, represented by Changkeng gold deposit, in which gold occurs in gold-bearing siliceous rocks (Wang et al.,1994); (4) Granite intrusions and internal and external contact zone type gold deposits, such as Zhanggongling-Longshui gold deposit.
Each ore belt in this area has the following characteristics: ① Agao polymetallic ore belt in Lianshan area has a silver-gold-lead-zinc metallogenic combination, and the typical deposits are Jinshan and Mei Dong; (2) The Qingyuan gold belt in Deqing has mineralization combinations such as AuAs and AuCu, and the representative deposits are Xinzhou, Jingcun and Hetai; ③ Luoding Yunfu Ag (Au) polymetallic ore belt, which represents the deposits of Chadong (Ag-Au-As-Pb-Zn combination), Jinziwo (Sn-Ag-Pb-Zn-Cu combination) and Zhanggao (Ag-Pb-Zn-Sn combination); ④ The typical deposits in the Xinyi gold belt (gold-arsenic-silver combination) in Gaozhou are Bajia and Dunling; ⑤ The silver-gold polymetallic ore belt in Lianjiang area is represented by Pangxidong (silver-gold-lead-zinc combination); ⑥ Gezhen gold belt in southwest Qionghai, starting from Shilu mining area in Changjiang County in the north and reaching Bumo in Dongfang County in the southwest, is more than 60 kilometers long and 6 ~ 12 kilometers wide. This belt has a series of gold mines such as Shuiwei, Tuwai Mountain, Baoban, Niu Ling, Dimei, Datian, Bumo (not grinding) and Gongai. The above six zones are prospecting targets worthy of further attention.
(8) Altai-Jimunai Gold Ore Prospecting Area
This area is located in Altai Mountain area in northern Xinjiang, southwest of Irtysh River basin to Jimunai area, and crosses Altai Caledonian geosyncline orogenic belt and Irtysh Hercynian orogenic belt. It includes Hongshanzui metallogenic belt, Erqisi metallogenic belt and Sawuer metallogenic belt. The Erqis deep fault between the north and south belts is of great significance to diagenesis and mineralization. Most of the volcanic eruption and intrusion activities in Hercynian period were distributed along this fault. The Tulgen-Hongshanzui fault, Abagong-Kurti fault, Erqis fault, Prichinsk-Wulungu fault and Clatot Gela-Barik fault in this area control the distribution pattern of gold mineralization in this area. The marginal areas of these fault zones are important prospecting targets, and the southern margin of Altai is an important gold enrichment area in this area.
(9) Western Junggar Gold Ore Prospecting Area
Located in the northwest of Junggar basin, this belt is composed of Caledonian and Hercynian complex structural systems. Nearly 200 rock gold deposits (spots) have been discovered in this area. Mainly distributed in the Hatu mountain area in the west Zhun. Gold mineralization is closely related to volcanic activity and intrusion in Hercynian period. The representative deposits are Chromengou, Qiu Qi I, Qiu Qi II, Baogutu, Huilushan and salto Sea in Toli County.
This area has a certain prospecting prospect in the contact zone with Hercynian volcanic rocks and intrusions. The resources predicted by XiZhun are 341t.
(10) west Tianshan gold exploration area
This area is an area with superior geological conditions for gold mineralization in the west of China, and has a great prospect for gold mineralization. This belt extends westward to Kazakhstan, and is connected with the Su Keke-Tekere Pb-Zn (Au) ore belt, which is an important target area for finding volcanic-type gold deposits and micro-disseminated gold deposits. Volcanic gold deposits mainly occur in the north and south sides of Yining Basin. The Lower Carboniferous volcanic rocks widely distributed in this area include volcanic hydrothermal type, volcanic sedimentary type and volcanic sedimentary-hydrothermal transformation type gold deposits. Special attention should be paid to the triangle of Awulale in the southeast of Axi Gold Mine, Nu Mountain and Huck Mountain in Poroch and the north of Jing. Gold deposits are controlled by regional large faults and volcanic mechanisms. This kind of gold deposit is represented by Axi Gold Mine.
Micro-disseminated gold deposits are mainly distributed in the southern part of the western Tianshan Mountains, which are related to Paleozoic (including pre-Paleozoic) carbonaceous rock series. Shen et al. (1994) further divided the area into six sub-areas: ① Tex-Jingbulake area; ② The middle reaches of Sukoko; ③ Upper reaches of Su Keke River; ④ Kule River-TEDA Banyuan Scenic Area; ⑤ Keqike remote scenic spot; ⑥ Monkdesai scenic spot.
The potential resources in this area are about 10 10.53t (Chen Yuchuan et al., 1999).
(1 1) East Tianshan-Beishan Gold Ore Prospecting Area
This area is located in the Paleozoic continental margin accretion zone and Beishan rift zone in Jueluotag, where marine volcanic rocks of Lower Carboniferous and Hercynian granitoids are developed. The main gold mineralization in this area belongs to volcanic rocks and occurs in intrusive bodies and internal and external contact zones. Mineralization occurred in Devonian-Carboniferous island arc volcanic rocks and pyroclastic rocks, and was controlled by large ductile shear zones. The famous deposits are Yingshitan, Kanggur, 2 10, Mazhuang Mountain and Shuangjian Mountain in Hongshi area of Gansu Province. Located in the north of Dunhuang-Jiuquan, Beishan area in Gansu Province is a promising gold, silver and precious metal metallogenic area, and more than 20 gold mines have been discovered. Gold deposits are mainly distributed in late Paleozoic (mainly Carboniferous) marine volcanic rocks, and the host rocks are mainly intermediate-acid volcanic rocks, and the mineralization is controlled by structural zones and ductile shear zones.
(12) western Sichuan and Yunnan
The western Sichuan-Yunnan region includes Ganzi, Litang, Yidun and Xiangcheng in the western Sichuan in the north, and Ailao Mountain in the western Yunnan in the south, which mainly belongs to the western Sichuan-Yunnan region in the Nujiang River, Lancang River, Jinsha River and Red River basins. The earth spans the margin of the Yangtze platform, the margin of the Indian plate and the tectonic transition zone between them.
The gold deposits in this area mainly belong to: ① alkaline porphyry contact zone (Beiya) and volcanic hot spring type gold deposits (Tengchong two rivers); (2) Granite contact zone type gold deposits (Gongdingshan in western Yunnan, Daping in Yuanyang, Mianning Machine Room in western Sichuan); ③ Sedimentary rock type (micro-disseminated type) gold deposits (Zhacun in Weishan, western Yunnan, Shangmanggang in Luxi, Qiuluo in Ganzi, western Sichuan); ④ Metaclastic rock type gold deposit (Zhenyuan); ⑤ greenstone belt type gold deposits (Huangjinping, Sandiao, Dengzhanwo, Jintaizi and Mianning Tea Shop in Kangding, western Sichuan).
This area can be divided into: ① Tengchong metallogenic belt; ② Baoshan-Zhenkang metallogenic belt; ③ Changning-Menglian metallogenic belt; ④ Ailaoshan metallogenic belt; ⑤ Yunling metallogenic belt; ⑥ Lanping-Simao metallogenic belt; ⑦ Ganzi-Yidun-Zhongdian metallogenic belt; ⑧ Ninglang-Dali metallogenic belt. In recent years, a number of gold deposits or abnormal mineralization areas have been discovered in western Yunnan and western Sichuan. They are: ① Changjie-Weilong gold mineralization area; ② Dong Bang (Yunxian)-Banpo (Jinggu) mineralization area; ③ Menghai Xiding-Brown Mountain mineralization area; ④ Yulong-Xinlong mineralization area in western Sichuan; ⑤ Weishan Zijinshan-Waigucun mineralized area; ⑥ Weishan-Dafoshan mineralized area. Many ore occurrences have been found in these mineralized areas, such as Jueba Mountain, Seka, Nyadak, Xionglongxi and Xiaolongtan Village, so it is necessary to do further geological work. We should pay close attention to the prospecting work in the northern section of Ailao Mountain.
Eastern Tanggula Mountain (13) gold metallogenic prospect area.
This area is located in Bomi-Chayu area in eastern Tibet, and the Gangdise-Tengchong active belt of Tibet-Yunnan plate turns from east to west to north and south. There are few Paleozoic outcrops in this area, mainly clastic rocks mixed with carbonate rocks, and sporadic outcrops in Upper Jurassic-Lower Cretaceous. Mesozoic volcanic complexes, Hercynian and Indosinian granodiorites, Yanshanian and Himalayan granites are widely developed. The level of geological work in this area is very low. Although no gold deposit has been found yet, there are large-scale geochemical anomalies in this area, and the resources are estimated to be large, which has certain prospecting prospects.
(14) Xigaze-Lhasa gold exploration area
This belt is located at the junction of Yunnan-Tibet plate and India plate, that is, the Yarlung Zangbo River junction zone and its continental margin active zone. From north to south, it consists of Gangdise continental margin volcanic arc, Xigaze forearc basin flysch wedge, Yarlung Zangbo ophiolite belt, blueschist belt and migmatite belt. Himalayan granite and Mesozoic clastic rocks with carbonate rocks are widely developed in Gangdise-Tengchong volcanic belt in Lhasa area, with favorable metallogenic geological conditions and good geochemical anomalies. Gold deposits related to Himalayan granite have been found in Lhasa area, where placer gold deposits are widely distributed and have great potential for resource estimation. Attention should be paid to finding island arc type, volcanic type, fractured zone altered rock type and skarn type gold deposits related to granite.
3. Geological prospecting should be changed from general geological prospecting to geological prospecting centered on targets (ore deposits, mining areas and ore fields).
With the development of modern science, the combination of marginal disciplines and geosciences has spawned many new prospecting ideas and developed more prediction methods. Among them, computer technology has played an inestimable role in the progress of modern earth science. Some problems that could only be discussed in theory in the past, such as a series of methods of mathematical analysis, can now be operated on microcomputers. Therefore, many forecasting methods and a large number of forecasting results have been produced in recent years. However, these achievements are similar, and only the metallogenic belt (prospect) is delineated. Before computers were used for information processing, China geologists had shown extraordinary wisdom in this respect and won the great development of geological prospecting in China in 1950s and 1960s, thus laying the foundation for the development pattern of gold deposits today. What we are facing now is not the problem of how many metallogenic prediction areas there are, but the determination of specific deposits, mining areas and ore fields. Therefore, the prospecting and prediction work should focus on finding specific deposits and increasing recoverable reserves. At present, although the prediction methods of ore quantity are different, they mainly take the known area with good mineralization as the model area, then determine the score of the unknown area by comparing the similarity between the unknown area and the model area, and finally get the predicted ore quantity through various statistical analysis methods. There are many imperfect assumptions: ① Mineralization is an extremely complicated geological process, which is not only restricted by the metallogenic geological environment, but also by the source of ore-forming materials, mineral quantity, heat source, water source and metallogenic fluid dynamic system. In addition, the sedimentary conditions of minerals also control the spatial location of mineralization to a great extent. It can be said that no deposit in the world is completely similar to another deposit. Even different ore sections in the same ore body are different, and the metallogenic environment in the same ore body is basically similar (at least in small-scale metallogenic prediction). So whoever has seen the example of infinite extension of ore bodies shows that there are certain differences between deposits, and how reliable the application of traditional ore deposit similarity is, which deserves further discussion, so the metallogenic prediction based on this background is not credible in theory; (2) In the same area, deposits with large mineralization intensity, large ore body scale and obvious metallogenic characteristics are always found first. If there is the same deposit in the unknown area, why can't geologists find it after repeated prospecting? This is enough to prove that the deposit in the unknown area is different from that in the model area, or it is buried deeply and there is less information exposed on the surface. (3) Because of the complexity and incomplete similarity of the metallogenic process, the result of analogy based solely on geological indicators is uncertain; ④ The degree of geological research between the prediction area and the model area is different, and the reliability of geological data is not equal, thus reducing the reliability of metallogenic prediction results. To sum up, the ore quantity prediction methods currently used are not only incomplete in theory, but also have many difficulties in practical application. The general impression is that the predicted ore quantity is often higher than the actual ore quantity, and even misleads the geological prospecting. Therefore, geological prospecting should be changed from general regional mineral aggregate prediction to targeted work to increase China's gold reserves. Among them, it is of great significance to study the metallogenic theory, metallogenic indicators and prediction methods under the guidance of the new theory. The author thinks that it is effective to develop a prediction method centered on fluid mineralization (Lin Wenwei et al., 1998,1999; Lu Guxian et al., 1999).
4. Exploration should focus on detailed geological survey.
Throughout the 50-year history of China's geological work, I deeply feel the importance of basic geological work, and we should also attach importance to basic geological work under the same conditions. Systematic geological survey and corresponding general survey and prospecting work have been widely carried out in the eastern part of China, but this work has not been completed in the central and western regions, thus making the regional prospecting work a tree without roots and passive water. In recent years, various units have done a lot of work on the geological prospecting model of gold deposits. He has accumulated some experience in remote sensing, aerial geophysical exploration, geological interpretation of ground geophysical and geochemical exploration, determination of field metal content and related elements, and delineation of ore-controlling structures. If the systematic geological survey of the new area can be combined with these achievements, we will certainly get more prospecting information, especially the application of ground satellite positioning system provides a very convenient tool for geological work in areas with poor geographical conditions. The regional survey in eastern China was mainly completed in 1950s, and the geological data of some key areas need to be refreshed.
5. Accelerate the research on the metallurgical scheme of micro-disseminated gold deposits and promote the construction of Shaanxi-Gansu-Ningchuan gold mine base.
In recent years, China's geological circles have done a lot of work on the occurrence state and metallurgical methods of fine disseminated gold deposits, and made gratifying progress. However, due to the unique complexity of this kind of gold deposits, there is no effective and low-cost scheme for industrial utilization. In view of this, experts in geology, metallurgy, chemistry and other related disciplines should be concentrated to tackle key problems and strive for an early breakthrough, which is of great significance to the economic construction of the central and western regions of China.