Work understanding and achievement

1. Guided by the viewpoint of plate tectonics, this paper comprehensively discusses and reproduces the history of regional plate tectonics, and puts forward some new understandings.

(1) reconstructed the evolution history of multicycle plate tectonics. It is pointed out that the study area has experienced the evolution stage of the ancient Asian Ocean represented by Bainaimiao-Xilamulun suture zone (Precambrian to Early Paleozoic), the evolution stage of the southern Mongolian Ocean represented by Hegenshan suture zone (middle and late Paleozoic), the evolution stage of the Mongolian-Okhotsk Ocean represented by Mongolia-Okhotsk suture zone (early Mesozoic, mainly Indosinian) and the intraplate structure represented by the formation of Daxinganling orogenic belt and a series of intracontinental extension basins. The characteristics of tectonic evolution and related tectonic environment in each stage are expounded respectively.

(2) The dynamic mechanism of Mesozoic metallogenic explosion is discussed. It is proposed for the first time that the Mesozoic (Cenozoic) geological tectonic evolution in this area is controlled by the composite action of regional multiple tectonic dynamic systems, showing complex tectonic-magmatic activities. ① Continuity, that is, since the late Paleozoic North China Plate merged with ancient Mongolia and entered the collision stage, this area has been in a state of collision with post orogenesis for a long time; (2) superposition, that is, the middle and late Mesozoic was influenced by the long-range superposition effect of the North Mongolia-Okhotsk suture zone and the East Pacific subduction; ③ Transformation, that is, since the late Jurassic, Inner Mongolia has gradually transformed from the nearly east-west to the paleo-Asian ocean tectonic system to be mainly controlled by the north (N) east coastal Pacific tectonic system, which reflects the complexity of the Mesozoic-Cenozoic regional stress field conditions (superposition and transformation coexist); (4) Neogenesis, reflecting that this area was also controlled by the large-scale thinning of the regional lithosphere during this period. This complex multi-dynamic tectonic system sometimes strengthens and sometimes cancels the comprehensive action of regional stress. The related intraplate tectonic-magmatic activities have the characteristics of intermittent, strong and weak, complex causes and various types, but they are not very typical. The complex tectonic dynamic background of Mesozoic (Cenozoic) is the fundamental reason for the Mesozoic polymetallic mineralization explosion and the formation of unique polymetallic deposits in this area.

(3) Explain the fundamental reason why porphyry deposits and VMS deposits appear in the same orogenic belt at the same time. It is pointed out that the volcanic sedimentary basin has the characteristics of intermittent evolution from the inter-arc (upper) basin to the intracontinental extension basin from west to east in space and from late Paleozoic to Mesozoic in time, which reflects the diachronic nature of plate suture and the complete process from ancient ocean suture to collision proliferation and extension, and is restricted by complex geodynamic background. The volcanic deposits in the same basin have both inheritance and regeneration. This basin volcanism-sedimentation with long evolution time and complex structural background provides a good geological environment and material basis for the formation of copper, lead, zinc, silver and other polymetallic deposits in this area. Multi-basin evolution is accompanied by multi-cycle plate subduction, island arc volcanism and basin volcanism-sedimentation simultaneously. This regional tectonic framework is one of the typical characteristics of the wide and slow accretion orogenic belt in this area, and it is also the fundamental reason for the coexistence of porphyry and VMS polymetallic deposits.

Secondly, the present situation and characteristics of polymetallic deposits are comprehensively summarized, and the types of regional polymetallic deposits are divided.

(1) summarizes and divides the main types of regional metal deposits. ① Sedimentary metamorphic iron deposits in Proterozoic continental margin depression trough or ancient rift environment. ② Porphyry Cu-Au, Cu-Mo (Au) deposits (Bainaimiao, Occidental Tolgoi, Chagan Subul, etc. ) and volcanic Cu-Au polymetallic deposit (Oyoute et al. ) occurs in the island arc environment. (3) submarine volcanic eruption (flow)-sedimentary iron, lead and zinc polymetallic deposits (Chaobuleng, Chagan Aobao), sub-(volcano)-sedimentary copper, lead, zinc, silver and gold polymetallic deposits (Jilin Baolige, Wulan Tolgoi, Suizhong Chagan, etc. ) and lead-zinc deposits (lead-zinc deposits) of structurally fractured altered rocks ④ Basic-ultrabasic rock-type or ophiolite-type iron-copper-gold deposits (Xiaobaliang) and chromite deposits (Hegaola) occurring in collision suture zones (Early Paleozoic and Middle Paleozoic). ⑤ Porphyry Cu-W-Bi polymetallic deposits, ductile shear zone (altered rock) gold deposits, chronological vein gold deposits and continental volcanic or volcanic-sedimentary Pb-Zn-Cu-Ag polymetallic deposits. ⑥ Porphyry Cu-Ag, Cu-Mo-Bi, Cu-Au deposit, skarn Pb-Zn-Cu or Cu-Pb-Zn deposit, isochronous Sn-Cu, Ag-Pb-Zn deposit, tungsten deposit, porphyry-isochronous Pb-Bi deposit, volcanic Cu-Sn-Ag-Pb-Zn deposit, and volcanic Cu-Au polymetallic deposit.

(2) Study on main typical mineral deposits. The geological characteristics, occurrence environment, ore-controlling factors and genesis of main types of polymetallic deposits are emphatically discussed. As a contrast, the super-large porphyry copper, molybdenum and gold deposits recently discovered in neighboring areas, especially Mongolia, are introduced.

Thirdly, according to the latest achievements of modern regional metallogeny, it is pointed out that the research idea of regional metallogeny will shift from post-summary and comparison to transcendental judgment and analysis, so as to improve the predictability and further strengthen the guiding role of metallogenic theory research in prospecting practice. On this basis, the regional metallogenic problems are discussed in depth.

(1) put forward the theory of ore-forming specificity in geological environment. That is to say, in a specific geological environment, specific metal deposits (types) or their combinations, ore-forming elements (or their combinations) and some symbolic geological features will be formed, which is considered as one of the basic theories for studying and discussing regional metallogenic laws. Geological environment includes geological tectonic environment and geochemical environment. The former provides a spatial basis for mineralization, while the latter provides a material basis for mineralization. They are organically linked or coupled through geological processes, then mineralize, and finally form a deposit in a suitable place. Each aspect can be divided into different levels.

(2) Analysis of regional metallogenic geological tectonic environment. Guided by the exclusive theory of geological environment mineralization, according to the history of regional tectonic evolution, the regional metallogenic geological tectonic environment can be divided into: ① Precambrian paleocontinent and passive continental margin (rift) environment; ② Early Paleozoic trench-arc basin tectonic environment; ③ Middle-late Paleozoic trench-arc basin and collision orogenic environment; ④ Early Mesozoic (post-orogenic) intracontinental extensional tectonic environment; ⑤ The complex environment of late Mesozoic-Cenozoic multi-tectonic dynamic system. On this basis, the working area is divided into five metallogenic sub-zones (belts) from north to south, and some metallogenic belts are divided into several metallogenic concentration areas. Namely, the Honggeer-Dalaimiao copper, molybdenum and gold metallogenic area (Ⅰ) (including two metallogenic concentration areas), the Erenhot-Tarrigen Aobao polymetallic metallogenic belt (Ⅱ) (including five metallogenic concentration areas), and the Suzuoqi gold, copper, tungsten, bismuth and iron metallogenic area (Ⅲ).

(3) Analysis of regional metallogenic geochemical environment. According to the results of regional basic geological work, the metallogenic geochemical environment in this area is discussed from two aspects: regional geochemical blocks and geochemical structure of crust and mantle. The study area is divided into four geochemical blocks, namely Su Nite Zuoqi gold-bismuth-iron-chromium-copper-tungsten-molybdenum block, Erenhot-alatan Heli copper-lead-zinc-gold-silver-tungsten-molybdenum-bismuth block and Dongwuqi copper-lead-zinc-silver-tin-gold-antimony-bismuth block. It is pointed out that the upper crust is dominated by Zn-Pb-Ag, the lower crust is dominated by Bi-Pb-Zn-Ag-Cu-W-Sn-U-Mo and rare elements, and the mantle is dominated by Cu-Fe-Au-Cr-Co-Ni-Sn-Bi. On this basis, combined with the spatial transformation of geological tectonic environment and the characteristics of tectonic-magmatic activity in different regions, the characteristics of metallogenic geochemical element combination in different regions are expounded.

(4) The ore-forming specificity and evolution of different regional ore-forming environments are comprehensively discussed. Mineralization in this area occurred early and in many stages, mainly in two stages: Paleozoic (mainly middle and late Paleozoic, 65,438+07%) and Mesozoic (mainly Yanshanian, 58.3%). Mineralization is characterized by superimposed abnormal development.

(5) The regional polymetallic metallogenic series has been established. Include 2 main series and 5 sub-series. One is a metallogenic series related to the trench-arc basin tectonic environment formed by the closure of the South Mongolia Ocean in the middle and late Paleozoic, including three sub-series; The second is the metallogenic series related to Mesozoic, especially Yanshanian, and the combination of various tectonic dynamic systems, including two sub-series. The book points out for the first time that there are polymetallic mineralization of gold, copper, bismuth, tungsten and gold related to early Mesozoic (Triassic) alkaline granite in Zuo Qi area of Su Nite, which has a good prospecting prospect.

Fourthly, the potential of regional gold and copper resources is preliminarily evaluated.

According to the calculation of abundance method, it is considered that the total amount of gold resources with an area of nearly 40,000 km2 and a depth of 1000m can reach 960t, and the amount of copper resources can reach160,000 t. Abstract: The metallogenic characteristics of the South Mongolia metallogenic belt and the Erenhot-Dongwuqi metallogenic belt are compared and analyzed from the aspects of regional geological background, strata, structure and magmatic rocks, and it is pointed out that the porphyry copper polymetallic deposits in this area.

5. Regional metallogenic prediction based on DPIS system under 5.GIS platform.

On the basis of geographic information system, using the DPIS software developed by ourselves and the method of prospecting information, the regional mineralization of gold and copper deposits in the whole region is predicted. The information color block and isoline map of regional gold and copper mines are drawn, and on this basis, the prospecting areas of gold and copper mines are delineated respectively Among them, there are 10 gold prospecting areas, of which 2 are Grade A, located in Zuo Qi area of Su Nite and east of Dongwuzhumuqin Banner, and 3 are Grade B, namely Honggeer, Baiyinwula-Hada Temple, Xiaobaliang-and Genshan area. C 5 level; There are 7 copper (lead-zinc) prospecting areas 17, and 5 Class A areas, namely Suzuoqi, Dongwuqi-Chagan Aobao, Monogeqin-Azahada, Chagan Chulu-Oyute and Little Baratgin-Hagen Mountain. Class B includes three places, namely Hada Temple-Baiyinwula, Yihe Wuhua-Jirigalangtu and the southwest area of Dongwuzhumuqin Banner; The geological characteristics and prospecting problems of main metallogenic prospect areas are briefly reviewed.

6. From the perspective of metallogenic-prospecting system, the regional prospecting problem is studied and discussed in detail.

(1) systematically studied the change and preservation of ore deposits in this area for the first time. It is pointed out that the main controlling factors affecting the change and preservation of ore deposits after mineralization in this area are intracontinental orogeny, overall uplift and local depression of plateau, tectonic-magmatic activity after mineralization, climate, topography and weathering and erosion. The results of their influence on the deposit, especially the influence of aeolian sand on regional geochemical anomalies, are discussed respectively.

(2) Elaborated the regional prospecting strategy. It is pointed out that the main deposit types in this area include porphyry Cu-Mo-Au deposit, exhalative (gas) sedimentary (metamorphic) Pb-Zn-Ag polymetallic deposit, post-magmatic hydrothermal (isochronous) vein copper deposit, tungsten deposit, bismuth-tungsten deposit, tungsten-tin deposit, basic-ultrabasic rock-type Fe-Cu-Au deposit and tungsten deposit. Volcanic-subvolcanic (hydrothermal) gold and silver deposits and metamorphic iron deposits. The main attack areas are Su Nite Zuo Qi area, the northeast of Dongwuzhumuqin Banner, Jirgalangtu (north of Abaga Banner)-Aoyute in Dongwuzhumuqin Banner, Hegenshan-Xiaobaliang, Baiyinwula-Hada Temple in the north of Zuo Qi, Su Nite, etc. And it is necessary to find minerals in all areas.

(3) The prospecting criteria of gold and copper deposits are summarized. Focusing on gold and copper, this paper systematically summarizes the prospecting criteria of the main deposit types in the study area, and comprehensively discusses the applicability of different prospecting methods based on geochemical exploration, geophysical exploration and remote sensing and the problems that should be paid attention to in their use. Taking typical deposits as examples, this paper probes into the prospecting and exploration models of main types of polymetallic deposits from the aspects of geological output model, geochemical model and geophysical model. On this basis, the combination of prospecting techniques and methods suitable for different levels and types of metal deposits is systematically formulated.

Seven, the study of key mining areas has made new understanding, and the geological exploration in the exploration area has made important achievements, and submitted two gold producing areas.

Geological control and mineralization types of Bayan Windur mining area (1). It is considered that the gold mineralization zone in this area is a regional ductile shear zone developed by the contact zone between Permian sandstone and Mesozoic granite and its secondary structures. The intersection of the NE-trending fault and the nearly EW-trending ductile shear zone on the basin edge controls the production of gold deposits (points), and the distribution of the deposits (points) is nearly equidistant. From south to north, the regional mineralization types have the evolutionary transition characteristics of mylonite type, mylonite+chronological pulse type to chronological pulse type. On this basis, the main mineralization areas and prospecting direction of the mining area are determined.

(2) Study on the genesis of the deposit. The geological characteristics and genesis of gold veins in Bayan Windur mining area are roughly found out. Mineralization is characterized by the superposition of low-grade mylonite mineralization controlled by early NE-trending or NEE-trending ductile shear zone and high-grade time-dependent pulse mineralization controlled by late EW-trending brittle fracture. The time-dependent pulse controlled by the late brittle tectonic belt has a nearly equidistant distribution law. The former was formed in the regional continuous compression environment after Indosinian collision, and the mineralization was mainly related to metamorphic fluids during ductile shear deformation, while the latter was formed in the Yanshanian regional extension environment. Mineralization is mainly related to intermediate-acid magmatism. Minerals mainly come from deep magma and have obvious mantle source color. It is possible to find a large-scale mylonite deposit with low grade in the deep part of the mining area.

(3) Through further work, two new gold producing areas have been submitted. The resources submitted by BW mining area are (333+3341) 5821kg; The resources submitted by the mercury mining area are (333+334 1)2292kg. At the same time, it is pointed out that vein 9 in the south of the mining area has the potential for further work. Thus, a major breakthrough in gold prospecting in this area has been achieved.

Eighth, a number of new achievements have been made in the prospecting work in the periphery of the mining area, and five gold polymetallic prospecting targets for further work have been submitted.

They are (1) returning to lent and calling for Dugejin; ② Wulanhada copper and bismuth; (3) Tungsten and bismuth were recorded in Wu and Er places; ④ Senjige gold and tungsten; ⑤ Chagan Chulutukin, etc. Among them, Huizhaiyinhuduge, Wulanhada, Ukherchulu-Senjige and the existing Bilugan 'an tungsten deposits around them have formed large-scale polymetallic metallogenic belts in the NEE direction. Systematic geochemical profile measurement shows that the mineralized elements are enriched in stages, and the bismuth, gold and tungsten in the enriched section are abnormal, and some of them have reached industrial level, which has a good prospecting prospect.