Method for constructing metamorphic and ancient iron-copper polymetallic ore deposit mineralization alteration zoning and determining prospecting direction

Abstract

The invention discloses a method for constructing metamorphic and ancient iron-copper polymetallic ore deposit mineralization alteration zoning and determining the prospecting direction, and belongs to the technical field of mineral resource exploration. The method comprises the following steps: (1) carrying out large-scale (1: 200 or larger scale) mineralization alteration mapping on a typical middle section and a typical section of a target ore deposit; (2) on the basis of detailed chronology research results, systematically carrying out typical rock and ore comprehensive identification, and finding out the composition and characteristics of a metallogenic system; (3) summarizing mineralization alteration zoning rules of different mineralization systems based on results of the previous steps; (4) comprehensively constructing a mineralization alteration zoning mode; and (5) based on the constructed mineralization alteration zoning mode, proposing a deep prospecting direction of the target ore deposit. And an important basis is provided for prospecting exploration of the deep edge part of a mine field or an ore deposit.

Description

Technical Field

[0001] The invention relates to a method for constructing mineralization alteration zones of Proterozoic iron-copper polymetallic deposits and determining ore-prospecting directions, belonging to the technical field of mineral resource exploration. Background Art

[0002] In the Proterozoic iron-copper polymetallic deposits, mineralization and alteration are common, and the distribution of ore bodies has a certain regularity. Through the systematic study of mineralization and alteration zoning, an important theoretical basis can be provided for prospecting. However, in traditional prospecting methods, single technologies or combinations of technologies such as geological exploration, geochemical analysis, geophysical methods and remote sensing technology are mostly used as means, lacking a systematic multidimensional integrated analysis method. Compared with other types of copper-iron polymetallic deposits, Proterozoic iron-copper polymetallic deposits have the following characteristics: ① The geotectonic background is very different: most Proterozoic iron-copper polymetallic deposits are located on the edge of the Archean craton. The iron-copper polymetallic deposits in Kangdian area are all without exception hosted in 1.6Ga Paleoproterozoic metamorphic volcanic-sedimentary strata; ② The mineralization age is relatively old: the vast majority of IOCG deposits were formed in the late Paleoproterozoic to early and middle Proterozoic, and the mineralization ages of representative minerals such as zircon, apatite, chalcopyrite, and molybdenite are basically distributed in 1.6~0.8Ga; ③ The genetic type is complex: the mineral The mineralization provinces where the deposits are located all have the activity of magmatic rocks of the same period without exception, and vein-type, hydrothermal breccia-type, skarn-type, bedding-parallel replacement-type and composite deposit types are all developed; ④ The mineralization and alteration are relatively unique: sodium, calcium-iron, potassium-iron hydrothermal alteration and brecciation from regional to deposit scale are developed, and the alteration range is relatively wide; ⑤ Diverse mineral symbiosis: Due to the complex mineralization environment, the mineral symbiosis is diverse, containing a large amount of low-titanium iron oxides, the metal mineral oxides are mainly magnetite, the sulfides are mainly chalcopyrite, and there are also pyrite, hematite, chalcocite, bornite, native gold, etc. Gangue minerals include albite, diopside, actinolite, quartz, garnet, potassium feldspar, mica, feldspar, calcite, fluorite, etc. As a result, the study of the mineralization and alteration zoning law of this type of deposit is difficult. The complex geological background and changeable geological processes make the study of the causes of mineralization and alteration and their temporal and spatial distribution extremely complicated. Multiple mineralization types overlap with each other, and the wide distribution range and variety of various altered minerals make it difficult to identify the mineral symbiosis and effectively identify and distinguish them. The depth variation from shallow to deep is large, and the deep variation law is difficult to effectively extract. As a result, the deep prospecting direction is unclear, the prospecting efficiency is low, and the cost remains high. There is an urgent need for a new method that can construct a complete mineralization alteration zoning model and guide the prospecting direction. Summary of the invention

[0003] The present invention provides a method for constructing the mineralization alteration zoning and prospecting direction of the Proterozoic iron-copper polymetallic deposit. Based on the cataloging of the geology of the Proterozoic iron-copper polymetallic deposit, through detailed ore phase and mineralogy research, combined with modern rock and mineral analysis and testing technology, the metallogenic system composition of the Proterozoic iron-copper polymetallic deposit is divided, the mineralization alteration zoning laws of different metallogenic systems are summarized, the mineralization alteration zoning model of such deposits is constructed, and the deep prospecting direction is proposed; the specific steps are as follows:

[0004] S1. Carry out large-scale mineralization and alteration mapping of typical middle sections and typical sections of Proterozoic iron-copper polymetallic deposits, draw geological cataloging maps of typical sections of typical middle sections of Proterozoic iron-copper polymetallic deposits, identify alteration types, mineralization types, mineral symbiosis, identify important alteration minerals and their characteristics, and divide mineralization and alteration zones;

[0005] The large-scale profile geological cataloging map drawn in step S1 includes the following contents: ① the orientation, elevation, number and length of the profile; ② preferably select representative geological observation points, record the lithology (marble, metasodic lava or igneous rock), stratum occurrence (strike, dip, inclination), mineralization type (copper mineralization or iron mineralization), mineralization output form (layered mineralization, vein mineralization), mineralization intensity (strong mineralization, medium mineralization, weak mineralization, no mineralization), alteration type (carbonation, silicification, silicatization, etc.), alteration intensity (strong alteration, medium alteration, weak alteration, no alteration) and mineral paragenesis combination; ③ based on the detailed observation of different geological points, divide the mineralization alteration zone within the scope of the stratum exposed by the profile; ④ based on the detailed cataloging results of multiple profiles in the same plane (middle section), draw the plane (middle section) mineralization alteration zone map; ⑤ divide the mineralization period and mineralization stage. Collect representative ore and surrounding rock samples to provide detailed basic information for subsequent analysis.

[0006] S2. Systematically collect chronological data of Proterozoic iron-copper polymetallic deposits, conduct comprehensive identification of typical rocks and ores, and identify the composition and characteristics of the metallogenic system of Proterozoic iron-copper polymetallic deposits, as follows:

[0007] (1) Systematically collect existing literature and previous geochronological research results, mainly including zircon U-Pb, biotite Ar-Ar, garnet U-Pb, molybdenite Re-Os, and chalcopyrite Rb-Sr isotope geochronological data;

[0008] (2) Carry out comprehensive identification of ore and surrounding rock samples indoors, use optical microscope, electron microscope, and electron probe backscattering photography technology to analyze the microstructure and mineral association relationship of ore and surrounding rock samples, and find out the mineralogical characteristics and alteration phenomena of ore and surrounding rock samples;

[0009] (3) Based on the chronological data and the results of rock and ore identification in step (2), the composition of the metallogenic system of the Proterozoic iron-copper polymetallic deposit is determined, thereby identifying the potential mineralization environment and mineralization mechanism;

[0010] The mineralization system consists of ① jet sedimentary mineralization system; ② metamorphic hydrothermal superposition mineralization system; ③ hydrothermal superposition mineralization system;

[0011] S3. Based on the results of steps S1 and S2, summarize the laws of mineralization alteration zoning in different mineralization systems, explore the internal connection between mineralization alteration zoning, and reveal the spatial distribution of mineralization alteration characteristics in a systematic way;

[0012] (1) Based on the differences in mineralization and alteration zoning of different mineralization systems in different planes (middle sections), and based on the study of the geology and mineral assemblages of different mineralization and alteration types, the mineralization and alteration zoning shows specific change rules in different directions. For example, from the core area to the peripheral area, the grade, mineral composition and alteration characteristics of the ore show systematic changes, forming corresponding lateral zoning. The plane zoning rules are comprehensively analyzed and summarized;

[0013] (2) Based on the zoning rules of different planes, we pay attention to the changes in the characteristics and causes of mineralization and alteration in different mineralization systems with depth, and summarize the vertical changes of mineralization and alteration zoning.

[0014] S4. Based on the summarized mineralization and alteration laws, a mineralization and alteration zoning model is constructed. Using model reconstruction and geological mapping technology, the laws of extension of various types of alteration into the deep of the ore deposit are clarified. Based on geological characteristics and mineralization and alteration, a comprehensive deep prospecting direction is proposed to provide a basis for deep prospecting.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) Improve the efficiency of prospecting: By constructing the mineralization and alteration zones of Proterozoic iron-copper polymetallic deposits, the formation environment and evolution process of the deposits can be more accurately identified, thereby improving the efficiency of geological exploration and reducing the waste of resources caused by blind prospecting;

[0017] (2) Optimizing exploration strategies: This method can help geological prospectors clarify the distribution characteristics and mineralization laws of mineral deposits, thereby formulating more scientific and targeted exploration strategies and improving the success rate of prospecting;

[0018] (3) Reduce exploration costs: Through accurate mineralization and alteration zoning analysis, unnecessary exploration investment can be effectively reduced, saving manpower, material and financial costs, and bringing higher economic benefits to enterprises;

[0019] (4) Enriching theoretical research on mineral deposits: The proposed method is not only of guiding significance in practical applications, but also provides a new perspective for theoretical research on the formation mechanism of mineral deposits, promoting further development in the fields of geology and mineral resources;

[0020] (5) Promote the sustainable development of enterprises: Through reasonable resource exploration and mining, the sustainable utilization of mineral resources can be better achieved, the impact on the environment can be reduced, and the ecological balance can be promoted;

[0021] (6) Improve the utilization rate of mineral resources: Through in-depth research on mineralization and alteration zoning, we can have a more comprehensive understanding of the composition and characteristics of the ore deposits, thereby improving the recovery rate and utilization rate of mineral resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a catalogue of the 126-line section of the 280 middle section of a Proterozoic iron-copper polymetallic deposit in central Yunnan;

[0023] Figure 2 The results are the layered mineralization and alteration types of a Proterozoic iron-copper polymetallic deposit in central Yunnan. (a) shows the rough-surfaced magnetite, chalcopyrite, bornite and azurite in the volcanic eruption-sedimentary period, all of which are in anterior structure; (b) shows the hematite replacing rough-surfaced magnetite in the late volcanic eruption-sedimentary period, the hematite is in semi-prophogenic structure, and the magnetite is in anterior granular shape; (c) shows the rough-surfaced magnetite, chalcopyrite and pyrite in the volcanic eruption-sedimentary period, the chalcopyrite and magnetite are in anterior granular shape, and the pyrite is in semi-prophogenic-anterior granular structure; (d) shows the metamorphic bornite replacing chalcopyrite, both of which are in terior granular shape; (e) shows the magnetite being replaced by hematite in the metamorphic period, the magnetite is in terior granular shape, and the hematite is in semi-prophogenic-anterior granular shape; (f) shows the metamorphic (g) Granular garnet in the volcanic exhalation-sedimentary period and magnetite and chalcopyrite in the metamorphic period. Granular magnetite is replaced by chalcopyrite and garnet is in fragmented granular form. (h) Hematite is in the fragmented garnet in the metamorphic period and is infused with granular magnetite. (i) Granular garnet in the metamorphic period is completely chloritized (right), and chlorite begins to replace garnet (left). (j) Vein-like chlorite replaces garnet in the metamorphic period. (k) Vein-like chlorite and strip-like biotite in the metamorphic layer. (l) Granular albite and granular potassium feldspar in the exhalation-sedimentary period are encased by quartz and calcite.

[0024] Figure 3 It is a garnet type of a Proterozoic iron-copper polymetallic deposit in central Yunnan; (a, b) are microscopic photos of garnet 2-1; (c, d) are microscopic photos of garnet 2-1 and 2-2; (e, f) are microscopic photos of garnet 2-3;

[0025] Figure 4 These are the layered and veined chalcopyrite and bornite in the iron-copper ore area of ​​a Proterozoic iron-copper polymetallic deposit in central Yunnan; (a, b) are DHS-3 layered star-shaped and disseminated chalcopyrite, bornite and their samples, (c) are chalcopyrite and bornite with granular trachytic texture during the volcanic exhalation-sedimentation period, (d, e) are DM-28 hydrothermal superposition period veined chalcopyrite and bornite, DQ-8 veined chalcopyrite and bornite samples, (f) chalcopyrite and bornite coexist with quartz-calcite veins under the microscope; (g, h, i) are DHS-4 layered bornite and chalcopyrite with trachytic texture under the microscope, DG-156 veined chalcopyrite, bornite, pyrite tunnel (j)-sample (k)-under the microscope (l) granular pyrite, chalcopyrite and bornite coexist;

[0026] Figure 5 This is the mineral formation sequence of a Proterozoic iron-copper polymetallic deposit in central Yunnan;

[0027] Figure 6 This is a plan view of the layered mineralization-alteration zoning of the middle section 280 of a Proterozoic iron-copper polymetallic deposit in central Yunnan;

[0028] Figure 7 This is a plan view of the mineralization-alteration zoning of the middle section 340 of a Proterozoic iron-copper polymetallic deposit in central Yunnan during the hydrothermal superposition period;

[0029] Figure 8 This is a mineralization-alteration profile of the B128 line of a Proterozoic iron-copper polymetallic deposit in central Yunnan;

[0030] Fig. 9 This is a cross-section of the mineralization-alteration zoning of a Proterozoic iron-copper polymetallic deposit in central Yunnan;

[0031] Fig.10 This is a deep prospecting target area of ​​a Proterozoic iron-copper polymetallic deposit in central Yunnan; (a) is a plan view of the 60 prospecting target area, (b) is a cross-sectional view of the B128 line prospecting target area, and (c) is a cross-sectional view of the B84 line prospecting target area. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below through examples, but the protection scope of the present invention is not limited to the contents described above, and the methods in the examples are all conventional methods unless otherwise specified.

[0033] Example 1

[0034] The outcropping strata of a Proterozoic iron-copper polymetallic deposit in central Yunnan are, from old to new, the Archean Badu Formation (Ard) highly metamorphic mixed rocks and schists. The early Proterozoic Dahongshan Group are, from old to new, the Laochanghe Formation (Pt1dl), Manganghe Formation (Pt1dm), Hongshan Formation (Pt1dh), Feiweihe Formation (Pt1df) and Potou Formation (Pt1dp). The sandstones of the Ganhaizi Formation (T3g) and Shezi Formation (T3s) of the Upper Triassic are located above the Dahongshan Group and are in angular unconformity contact with the underlying strata.

[0035] The Manganghe Formation is mainly composed of deep-sea submarine volcanic eruption sediments, which are divided into (Pt1dm 1～4 ): hornblende sodium schist, garnet hornblende sodium schist, garnet hornblende / biotite schist intercalated with metasomatic tuff and scapolite dolomite marble; Hongshan Formation (Pt1dh) is located above the Manganghe Formation, which includes: It is a magnetite metamorphic lava (Pt1dh 1 ), felsic dolomite marble and garnet chlorite hornblende schist (P1dh 2 ), dark green almond-shaped flashing sodium lava (Pt1dh 3 ). In addition, there are the Feiweihe Formation (Pt1df) and the Upper Triassic (T3). The Feiweihe Formation is located in the southeast of the mining area, with a thickness of 375m, including dolomite marble and carbonaceous slate. The Upper Triassic includes the Ganhaizi Formation (T3g) and the Zi Formation (T3s). The Ganhaizi Formation is about 120m thick, including sandstone and carbonaceous mudstone, while the Shezi Formation is more than 150m thick and is mainly composed of feldspar quartz sandstone.

[0036] A Proterozoic iron-copper polymetallic deposit in central Yunnan contains 45.3 Mt of iron, with an average grade of 41.0%; 1.35 Mt of copper, with an average grade of 0.78%; 16 t of gold; and 141 t of silver. The deposit has significant multi-stage mineralization and is rich in metal elements such as lead, zinc, nickel, and lithium. The deposit consists of 7 mineral belts (Ⅰ~Ⅶ), each with different mineral characteristics. First, the Ⅰ mineral belt is located in the middle and upper part of the Manganghe Formation (Pt1dm 3 The second iron ore belt is located in the metasodic lava section of the lower part of the Hongshan Formation (Pt1dh 1 ), which is composed of multiple ore bodies. The third ore iron-copper ore belt is produced in the pomegranate hornblende chlorite schist section in the middle of the Hongshan Formation (Pt1dh 2 ), consisting of two ore bodies. The IV and V iron ore belts are both produced in the hornblende sodium lava section of the Hongshan Formation (Pt1dh 3 ) The VI poor iron ore zone is located in the hornblende sodium tuff section of the Manganghe Formation (Pt1dm 2 ) is composed of two ore bodies. Finally, the VIIth iron-poor copper ore belt is produced in the epidote-bearing hornblende-type sodium lava section of the Manganghe Formation (Pt1dm 1) bottom. In addition, this study also summarized the ore body characteristics of the vein condition, which is strictly controlled by the structure and mainly occurs in the tensile faults of the northwest-trending quartz / carbonate veins in the western mining section and the torsional-tensile faults in the north-south direction, with a dip angle greater than 60°. Spatially, it is represented by the development of a large number of ore-bearing faults in the core of the Dibadu anticline, and a large number of ore-bearing faults in the deep interlayer folds of the anticline wing.

[0037] S1: Carry out large-scale (1:200 or larger) mineralization and alteration mapping of typical middle sections and typical sections of the target deposit

[0038] The 120 and 122 veins in the middle section of 380 of a Proterozoic iron-copper polymetallic deposit in central Yunnan were selected as typical sections, and a systematic petrographic cataloging was carried out ( Figure 1 ). Common silicification, carbonation, biotitization, chloritization, sodiumization, and potashization are common. Among them, silicification can be divided into silicification alteration and quartz veins formed locally by the siliceous components precipitated by metamorphism. The specific outputs of sodiumization and potashization are albite and potash feldspar. Both early layered ores and late vein ores are related to them. Sodiumization enriches iron ore in the early stage, and the late stage is manifested as the intrusion of gabbro diabase. Potashization converts part of magnetite into hematite and biotite into chlorite in the early stage. The late alteration is characterized by a combination of sericite-hematite-chlorite-quartz veins. The volcanic eruption-sedimentation period and metamorphic period are mainly sodiumization, potashization, garnetization, chloritization, carbonatization and silicification. The main mineralizations are magnetite, chalcopyrite, bornite, molybdenite, pyrite, etc. The hydrothermal alteration is mainly quartz and dolomite veins. Mineralization is strictly controlled by fault structures. Mineralization is related to hydrothermal activity and is produced in different strata. The ore-bearing quartz veins vary in size, occurrence, and mineralization types. Layered ore bodies: Chalcopyrite (Cp1)-(Cp2)-Bornite (Bn1)-(Bn2) are the main ore body types. Cp1 and Bn1 are anterior granular with rough surface structure ( Figure 2 a, 2b, 2c), are products of volcanic eruption-sedimentation period. Cp2 and Bn2 are products of metamorphic period, and they are similar to rough surface structure ( Figure 2i). The two phases of minerals are both laminar and impregnated, and are produced in the metasomatic tuff and biotite schist of the Manganghe Formation and Hongshan Formation, forming a layered ore body. Vein ore body: A very promising ore body type in the mining area. Chalcopyrite (Cp3) and bornite (Bn3) are often in the form of clusters and veins and are produced in the interlayer tension (torsion) fault zone ( Figure 3 d, j), associated with quartz-dolomite-calcite, is the product of hydrothermal superposition, mainly filling and replacement; it is usually seen that the surrounding rock breccia is cemented by carbonate alteration, and the dissolution structure is developed in the cemented area. Chalcopyrite and bornite are commonly seen under the microscope with hydrothermal filling ( Figure 3 f, l). Silicification is one of the most developed alteration types in the mining area, which is closely related to copper-iron mineralization and has various forms. Carbonation is commonly found in this deposit, mainly in off-white-white-beige-brown hydrothermal calcite-ferrocalcite, dolomitization-ferrodolomite, etc. The spherical, stockwork, vein, and lens-shaped forms are distributed in the interlayer and bedding tension (torsion) fault zones and the intersection of the faults. There are also vein-like carbonate alteration that cuts through the surrounding rocks and ores. This type of alteration is often found in the garnet-bearing biotite schist and metasodic tuff in the third section of the Manganghe Formation. Biotite is seen to recrystallize in the fracture to form hexagonal columnar biotite clusters, accompanied by disseminated copper mineralization. Chlorite is present in both metamorphic and hydrothermal superposition periods. Chlorite is often developed beside layered minerals in the form of disseminated minerals. It is the product of rock mass auto-alteration and biotite alteration. Chlorite in veinlet minerals is commonly found in hydrothermal vein dissolution caves of metasodic tuff and in the contact area between the two. Garnet can be divided into three categories: (1) Fine-grained garnet (2-1), mostly found in mica schist belts, mostly broken and partially completely replaced by chlorite. (2) Medium-grained garnet (2-2), reddish brown, produced in granular or granular aggregates, with a grain size of less than 1 cm, containing cracks, and often interspersed or replaced by magnetite, quartz or carbonate. (3) Coarse-grained garnet (2-3), with a grain size of more than 2 cm. This type of garnet has coarse grains and is rarely interspersed with carbonate veins under a microscope. A small amount of chalcopyrite and magnetite can be seen in the cracks. It is not as broken as the former and has a more complete shape ( Figure 4). The iron-copper polymetallic deposit was studied through systematic geological surveys and petrological methods. The mineralization characteristics of each period were determined by comparative analysis of rock assemblages, mineral assemblages and geochemical characteristics of different periods. The mineralization periods are: (1) Volcanic eruption sedimentation period. In this period, the lithology is mainly volcanic clastic rocks and volcanic rocks. The mineral assemblages are mainly magnetite, hematite, pyrrhotite, chalcopyrite, bornite, gold, silver, etc., and the gangue minerals are mica, quartz, albite, potassium feldspar, dolomite, etc. The geochemical characteristics show that metal elements such as iron and copper are enriched. (2) Metamorphic period. In this period, the mineral assemblages are mainly chalcopyrite, pyrite, hematite, and pyrrhotite. The gangue minerals are garnet, potassium feldspar, biotite, dolomite, quartz, calcite, chlorite, epidote, diopside, etc. (3) Hydrothermal superposition period, in which the mineral assemblage is mainly composed of chalcopyrite, pyrite, bornite, chalcocite, native copper, molybdenite, and siderite, and the gangue minerals are quartz, calcite, dolomite, chlorite, etc. ( Figure 5 ). From the center of the layered copper ore body to the surrounding rocks, the order is: chloritized biotite metasodic tuff zone (Ⅰa) → carbonated garnet biotite schist zone (Ⅱb) → weakly carbonated metasodic tuff zone (Ⅲc) → carbonated marble zone (Ⅳd), among which Ⅰa is the ore-bearing center zone. Through the recording of multiple middle-section veins such as 280, 140, and 60, it is believed that the mineralization-alteration zoning of hydrothermal vein-type ore bodies from the center to the surrounding rock is: chalcocite mineralization quartz stockwork zone (Ⅰ) → bornite mineralization dolomitization coarse vein zone (Ⅱ) → chalcopyrite mineralization calcite fine vein zone (Ⅲ), and the vein-type ore bodies (alteration) are horizontally zoned from the northwest end of the core of the Dibadu anticline to the southwest wing of the anticline: chalcocite + bornite + (native copper) → bornite + chalcopyrite → chalcopyrite + pyrite. The alteration related to mineralization is carbonation, silicification, and chloritization.

[0039] S2: Based on detailed chronological research results, systematically carry out comprehensive identification of typical rocks and minerals to identify the composition and characteristics of the mineralization system

[0040] The composite mineralization system of this iron-copper polymetallic deposit is formed by volcanic exhalative sedimentation-diagenesis mineralization, regional metamorphism and hydrothermal superposition mineralization. Based on isotope dating of zircon U-Pb, chalcopyrite Rs-Os, molybdenite Rs-Os, amphibole and biotite Ar-Ar, the mineralization age data of the ore body of this deposit are mainly divided into three periods: 1681±13Ma~1659±16Ma, 1115±28Ma~1026±22Ma and 830±10Ma.

[0041] The ore bodies and their main ore-bearing rocks in the tunnels of the mining area were studied in detail. The volcanic eruption-sedimentation period and metamorphic period were the mineralization of the mineralization system. The main mineralization types were magnetite, chalcopyrite, bornite, pyrite and hematite.

[0042] The mineralization system of the deposit consists of ① jet sedimentary mineralization system; ② metamorphic hydrothermal superposition mineralization system; ③ hydrothermal superposition mineralization system;

[0043] S3: Based on the results of the previous steps, summarize the mineralization alteration zoning rules of different mineralization systems

[0044] Plane zoning rules: (1) Exhalative sedimentary mineralization system, taking the middle section of 280 as an example, a large-scale mineralization-alteration mapping of the middle section of 280 was carried out, and the mapping of each tunnel was summarized, the plane rules were summarized, and the plane map of mineralization and alteration zoning of the middle section of 280 was drawn. The ore body of the middle section of 280 changes from NW to NW near the B126 line. The mineralized body is also the most enriched near the B126 line, which is also the core of the Dibadu anticline. From the perspective of lithology, the metasodic tuff of the third section of the Manganghe Formation is the main ore-bearing rock. From the perspective of alteration zone, the chlorite carbonated metasodic tuff containing mica is the main ore-bearing rock in the middle section of 280. The ore body to the surrounding rock is chloritized carbonated metasodic tuff → carbonated garnet biotite schist → weakly carbonated metasodic tuff. Among them, garnet is mainly developed in the schist belt. Under metamorphism, a large amount of garnet is formed. However, garnet is developed in both schist and tuff, but the garnet in schist is denser ( Figure 6 (2) Metamorphic hydrothermal superposition mineralization system, controlled by the EW tectonic belt, is mainly manifested by regional metamorphism of volcanic exhalative sedimentary rock system, which enriches the copper-iron mineralization of the exhalative sedimentary mineralization system. Representative minerals are hornblende, garnet, scapolite, and mica. Metamorphic minerals are mostly directional. On the plane, the copper-iron ore bodies are mainly distributed in metasodic tuff intercalated with schist. The plane zoning law is: dark gray garnet-biotite schist intercalated with metasodic tuff → dark gray magnetite garnet-biotite schist → dark gray garnet-biotite metasodic tuff → gray striped brass metasodic tuff and garnet-biotite schist → dark gray garnet-biotite metasodic tuff → gray blocky magnetite metasodic tuff → dolomite marble. (3) Hydrothermal superposition mineralization system. Taking the middle section of 340 as an example, the vein mineralization is mainly bornite and chalcopyrite. The mineralization of the B126 and B148-B152 side lines is the main enrichment site. The mineralization is often produced together with quartz veins / quartz carbonate veins in the northwest / near north-south fault zone. In the whole ore deposit, the vein mineralization in the middle section of 340 is relatively strong ( Figure 7 ).

[0045] Vertical zoning rules: (1) Exhalative sedimentary mineralization system, by summarizing the mineralization-alteration zoning rules on different planes of the B128 line in the core of the Dibadu anticline, a profile mineralization-alteration zoning map is drawn. From top to bottom, the stratum dip angle changes from gentle to steep to gentle, and the most mineralized chlorite-carbonated mica-sodic tuff zone changes from thin to thick to thin ( Figure 8). (2) Metamorphic hydrothermal superposition mineralization system. The lithology changes greatly along the strike direction. From south to north, it changes from garnet-biotite schist, metasodic tuff and biotite dolomite marble to metasodic tuff and garnet-biotite schist. To the north of line B112, two-volume dolomite marble begins to appear, and metasodic tuff gradually decreases. To the north of line B152, all phases change to biotite dolomite marble and garnet-biotite schist. The iron ore bodies in the No. 1 ore belt also change from magnetite to magnetite, and from siderite to siderite from south to north. (3) Hydrothermal superposition mineralization system. The surface elevation of the deposit is 690m. This study was carried out from the middle section of 380 to the deep. The distribution law of vein minerals on different planes was summarized to summarize the law of the profile. In the middle sections of 340 and 280, the vein mineralization of line B126 is relatively strong, extending to the northeastern side of the drill hole along line B128 in the middle section of 140, where agglomerated bornite and native copper can still be seen. Based on this, it is speculated that the vein mineralization body is not at the same dip angle as the stratum, and the dip angle is greater than the dip angle of the stratum. Combined with the presence of multiple stockwork belts and large-scale quartz veins in the middle section of 60, it is judged that it does not dip in a single direction.

[0046] S4: Constructing a mineralization alteration zoning model

[0047] The lithological characteristics of the layered ore bodies of the deposit are obvious. For example, the No. 1 ore body is closely related to the third lithological section of the Manganghe Formation. Once entering the fourth lithological section - marble, the copper mineralization is significantly weakened or even disappears. The zoning of the deposit is mainly centered on the chloritized carbonate-transmuted sodium tuff, which tilts to the southwest on the southern wing of the Dibadu anticline and is distributed in a monoclinal manner. In addition, there are multiple interlayer small folds in the Dibadu anticline from the northwest to the southeast, so the schists on both sides of the mineralization center may be partially interlayered or thinned until they disappear. There is a certain correlation between each alteration zone and each type of mineralization: the chlorite-carbonated mica-sodic tuff zone (Ia) has the strongest mineralization, mainly chalcopyrite, bornite, magnetite, chlorite, dolomite, calcite, biotite, quartz, albite, garnet, metal minerals are mostly produced in laminar form, and gangue minerals are mostly produced in discontinuous veins, pods, and patches; the copper mineralization of the carbonated garnet-mica schist zone (IIb) is weaker than that of the Ia zone, but the iron mineralization is enhanced, and the mineral combination is: magnetite, hematite, bornite, chalcopyrite, garnet, calcite, quartz, potassium feldspar ; Weakly carbonated sodium tuff zone (Ⅲc), this zone is weakly mineralized, with occasional star-shaped copper mineralization, and magnetite is only thin-layered and banded. The mineral combination is: dolomite, calcite, quartz, garnet, biotite, chalcopyrite, pyrite, and magnetite; Carbonated marble zone (Ⅳd) This zone is the mineralized roof, with occasional star-shaped chalcopyrite and bornite mineralization only in the contact area with the tuff generation. The quartz and dolomite veins between the layers are denser than those of tuff, and the folds between the layers are more developed than those of tuff. The common strata are "U or V" shaped, and the axis is often consistent with the occurrence of tuff strata. In the process from the volcanic eruption-sedimentation period to the metamorphic period, the reaction changes from reduction to oxidation, which can be seen from the replacement of magnetite by pyrrhotite and the replacement of the first-stage magnetite by a large amount of hematite. During the hydrothermal superposition period, vein-like ore was strictly controlled by structure, and mineralization was present in the northwest / near north-south extensional tectonic belt. Due to the influence of the Dibadu anticline, the scale and density of the faults in the core of the anticline were significantly greater than those in the wing, and the mineralization in the core was also significantly stronger than that in the wing. From the south side of the core from west to east, there was a clear zoning of native copper → chalcocite + bornite + (native copper) → bornite + chalcopyrite → chalcopyrite + pyrite. It is divided into three zones according to its symbiotic combination relationship. In space, the core of the Dibadu anticline is a coarse vein zone, and the stockwork and fine vein zones are symmetrically distributed on both sides, showing a "mountain" shape on the section. The coarse veins in the core extend the highest in the vertical direction, and multiple groups of stockwork-fine vein-type veins appear in the deep on both sides ( Fig. 9 ).

[0048] S5: Based on the model constructed in S4, the deep prospecting direction of the target deposit is proposed

[0049] The ore bodies of this deposit are controlled by multiple factors such as rock mass and structure. Layered ore and vein ore are dominated by different mineralization processes. The distribution of different types of ore bodies has different regularities under different mineralization processes. For this deposit, the middle section of 280 is the most mineralized middle section. The mineralization is relatively weakened upward and downward, but there is no disappearance of mineralization. The strata are also relatively steep upward and downward. Therefore, it is speculated that large-scale mineralized bodies may reappear in the middle section where the next strata turn to be gentle. On the plane, B126 is the strongest mineralized part of the middle section of 280, the middle section of 140 is the B136 line, and the middle section of 60 turns eastward < B126, so an "S" shape appears on the deep profile. Therefore, there are two key areas on the deep plane. One is the B136-B126 line, which is below the elevation 0. There are four reasons for this: (1) The ore bodies that continue to extend to the southeast deep under the control of lithology are mainly located in the third section of the Manganghe Formation (Ptdm 3 ), (2) From shallow to deep, the number of copper-bearing quartz veins increases, the vein width widens, and the copper mineralization strengthens. (3) Laminated-hydrothermal vein-like mineralization alteration gradually strengthens, and the density of hydrothermal vein bodies increases. (4) According to the structural control ore characteristics, it is both the turning point of Dibadu and the development of interlayer tension-torsion faults. The second is that in the deep part of the SW side of the B84 line, below the ore-bearing elevation of 0m, there are hydrothermal vein-like ore bodies and layered ore bodies. (1) It is located in the part of the complex fold structure. (2) Mineral paragenesis and the reappearance of bornite. (3) The ore body is continuous and uninterrupted to the depth. (4) Mineralization alteration zoning: There may be large vein-like or stockwork-like mineralization alteration zoning in the depth ( Fig.10 ).

Claims

1. A method for constructing mineralization alteration zones of Proterozoic iron-copper polymetallic deposits and determining the direction of prospecting, characterized in that: Here are the steps: (1) Carry out large-scale mineralization and alteration mapping of typical middle sections and typical sections of Proterozoic iron-copper polymetallic deposits, draw geological catalog maps of typical sections of typical middle sections of Proterozoic iron-copper polymetallic deposits, identify alteration types, mineralization types, mineral paragenesis, important altered minerals and their characteristics, and divide mineralization and alteration zones; (2) Systematically collect chronological data of Proterozoic iron-copper polymetallic deposits, conduct comprehensive identification of typical rocks and ores, and identify the composition of the metallogenic system of Proterozoic iron-copper polymetallic deposits; (3) Based on the results of steps (1) and (2), summarize the laws of mineralization alteration zoning in different mineralization systems, explore the intrinsic connection between mineralization alteration zoning, reveal the spatial distribution of mineralization alteration characteristics, construct a mineralization alteration zoning model, use model reconstruction and geological mapping technology to clarify the spatial distribution characteristics of various types of alteration deep in the ore deposit, and propose deep prospecting directions for Proterozoic iron-copper polymetallic deposits based on geological characteristics and mineralization alteration.

2. The method for constructing the mineralization alteration zoning of the Proterozoic iron-copper polymetallic deposit and determining the prospecting direction according to claim 1, characterized in that: The geochronological data include isotope geochronological data of zircon U-Pb, biotite Ar-Ar, garnet U-Pb, molybdenite Re-Os, and chalcopyrite Rb-Sr.

3. The method for constructing the mineralization alteration zoning of the Proterozoic iron-copper polymetallic deposit and determining the prospecting direction according to claim 1, characterized in that: The specific operations to summarize the rules of mineralization alteration zoning in different mineralization systems are as follows: (1) Based on the differences in mineralization alteration zoning in different middle sections of different mineralization systems, and based on the study of the geology and mineral assemblages of different mineralization alteration types, the mineralization alteration zoning shows specific change rules in different directions, forming corresponding lateral zoning, and comprehensively analyzing and summarizing the plane zoning rules; (2) Based on the zoning rules of different planes, we pay attention to the changes in the characteristics and causes of mineralization and alteration in different mineralization systems with depth, and summarize the vertical changes of mineralization and alteration zoning.

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