Method for determining deep extension of ore body of magmatic hydrothermal polymetallic deposit by using element geochemical anomaly

Abstract

The present invention discloses a method for determining the deep extension of ore bodies in magmatic hydrothermal polymetallic deposits by using element geochemical anomalies. Based on large-scale structural alteration-lithofacies mapping and element geochemical content analysis, combined with the geological characteristics of the shallowly developed levels, through the compilation of element geochemical anomaly maps at different elevation planes and vertically, the spatial distribution characteristics and laws are summarized, and qualitative and quantitative indexes of element geochemical anomalies indicating the deep extension of ore bodies are further extracted, mainly including: quantitative evaluation indexes of element combination anomalies and the length, width and height difference of anomalies, and then a deep extension model of element geochemical anomalies in the unknown area in the deep part of the deposit is constructed, and finally the deep extension characteristics of hidden ore bodies are quickly determined; this method solves the problem of how to quickly identify the deep extension of deep ore bodies in the joint research process of traditional planar anomalies and profile anomalies, not only provides a new method for deep prospecting prediction, but also provides an important basis for the layout of prospecting engineering in deep prediction areas.

Description

Technical Field

[0001] The present invention relates to a method for rapidly determining the deep extension of ore bodies in magmatic hydrothermal polymetallic deposits by using elemental geochemical anomalies, and belongs to the field of mineral resource exploration. Background Art

[0002] China is the largest country in the world in terms of consumption and production of mineral resources. In the resource services of many large - super large main mines in recent decades, the shallow - easy - to - mine resources have been decreasing year by year and exhausted, and it has become an irresistible trend to search for resources in the deep part of known deposits. At present, the mining and exploration depths of most mines have reached or are close to 1 km. Thus, deep - seated mineral resources are one of the important guarantees for China's resource security. Deposits related to magmatic hydrothermal processes are the main sources of many metal resources, such as lithium, rubidium, cesium, tungsten, tin, molybdenum, copper, lead, zinc, silver, etc. Such deposits have characteristics such as relatively high average grade, large reserves, many ore - type varieties, obvious metallogenic characteristics, and great potential for deep - seated prospecting. At present, there is no relatively mature and reasonable technical method for deep - seated prospecting of such deposits.

[0003] As a method for effectively reflecting deep - seated mineralization information for prospecting exploration, elemental geochemical anomalies can organically combine the two core problems of metallogenic space and element migration that plague geological prospecting. Therefore, this technology has remarkable effects and good application prospects in the deep and peripheral prospecting prediction and rapid evaluation of polymetallic deposits significantly controlled by structures. In previous shallow - level explorations, the combined application of element combinations and geochemical anomalies has been relatively common, and the identified geological anomalies at the shallow level can provide important basis for searching for hidden deposits. Existing elemental geochemical anomalies mostly focus on the qualitative description of the types, distributions, and characteristics of shallow - level geological anomalies. Based on this, potential geological anomalies are analyzed and delineated, and the deep - seated mineralization information of deposits is predicted, and the occurrence characteristics of deep - seated ore bodies are speculated. However, shallow - level anomalies are difficult to effectively indicate the occurrence laws and spatial variation characteristics of deep - seated ore bodies, and at the same time, the effective extraction of qualitative and quantitative deep - extension indication signs has not been achieved, and deep - seated mineralization information is difficult to effectively extract, resulting in general effects in guiding deep - seated prospecting exploration. In this process, there are generally adverse factors such as using single - element anomalies to evaluate blind ore bodies and relying on the subjective judgment of geological personnel, resulting in general prospecting effects.

[0004] Therefore, in the urgent task of searching for deep - seated replacement resources, how to effectively, economically, and rapidly achieve the comprehensive evaluation of deep - seated minerals has become a frontier field of current research in the geological community. Therefore, it is necessary to propose an economic and effective exploration technology to rapidly evaluate deep - seated ore bodies. Summary of the Invention

[0005] In view of the technical problem of how to quickly determine the deep extension of the ore body in magmatic hydrothermal polymetallic deposits by using element geochemical anomalies, on the basis of element geochemical research, through the construction of the overall distribution models of planar and sectional geochemical anomalies; combined with the geological characteristics of the developed levels, and then according to the characteristics of element geochemical anomalies, judge the extension laws of deep rock masses and ore bodies, extract the structural geochemical anomaly indexes indicating the deep extension of rock masses and ore bodies, including the length, width and height difference data of planar and sectional geochemical anomalies, and then quickly infer the shapes and occurrences of deep rock masses and ore bodies.

[0006] The method for quickly determining the deep extension of the ore body in magmatic hydrothermal polymetallic deposits by using element geochemical anomalies of the present invention is as follows:

[0007] I. Extract the element geochemical anomaly indexes indicating the deep extension of the ore body

[0008] 1) Select several exploration lines and prospecting cross-cuts on a certain magmatic hydrothermal polymetallic deposit for large-scale structural-altered rock facies mapping. At the same time, collect structural rock samples with well-developed fracture fissures and close ore-forming relationships at a certain interval. The samples include cataclastic rocks, breccias, cataclasites and fault gouges, etc. Conduct detailed classification, description and identification of these structural rock samples, and then process and reduce the collected samples into test samples;

[0009] 2) Detect the trace element contents of the reduced test samples, sort out all effective detection data, take the common logarithm of all effective detection data, and use statistical analysis software to obtain the skewness coefficient and kurtosis coefficient of a single element. When both coefficients are less than 1, it is considered to meet the normal distribution. After all elements are tested, select the elements that meet the normal distribution;

[0010] Use statistical analysis software to perform factor analysis and cluster analysis on the contents of the selected elements. Under the factor analysis module, set the maximum number of factors to 5 or 6 and the minimum number of factors to 0.1. On the premise of maximum orthogonal rotation, obtain the factor table and scree plot of different element combinations; when the total contribution rate of different factor variances > 70%, obtain the number of factors. When the absolute value of the load > 0.5, obtain the factor score table of the representative element combinations of different samples, and use F i to represent the factor score, where i = 1, 2, 3,... n, and then obtain different types of element combinations in different factors; through the above analysis, on the one hand, divide the effective element combinations, and on the other hand, obtain the composite factor combinations of planes and sections at different elevations;

[0011] Then, count the spatial coordinates of the samples at different sampling positions and assign different factor scores to them, that is, X, Y, F i ; Import the data of different factor scores with spatial coordinates into contour drawing software to draw the element combination anomaly contour maps of different planes and sections.

[0012] The statistical analysis software is SPSS, STATISTICA, etc.; the contour drawing software is Mapgis, Surfer, Origin, etc.;

[0013] 3) Determine the lower limit of trace element anomalies, specifically, first remove the maximum value in the effective content detection data, and after multiple removals according to the extremely high value greater than three times the standard deviation, the lower limit of anomalies is the average value of the content plus two times the standard deviation. If the lower limit of anomalies of some elements is still higher than the content of the corresponding elements in the unaltered rock through calculation, the element contents are arranged from small to large, and the value at the one-third position is taken as the lower limit of anomalies; according to the lower limit of anomalies, the high-value anomaly areas and low-value anomaly areas of different factors are circled in the element combination anomaly contour map in step 2), wherein the high-value anomaly refers to the data being higher than the lower limit of anomalies;

[0014] 4) superimposing the element combination anomaly contour maps of different planes and sections in step 2) with the geological maps of different planes and sections of the ore deposit obtained after mapping in step 1) according to the corresponding spatial coordinates, and obtaining the geochemical anomaly-geological maps of different planes and sections, and obtaining the distribution characteristics of anomalies of different factors from the maps, including the number, range, shape and size of anomalies; combining the geological facts of different planes and sections, determining the geological significance of mineralization or weak mineralization represented by the high-value anomaly area, and the geological significance of unmineralized or surrounding rock represented by the low-value anomaly area;

[0015] 5) Based on the geochemical anomaly-geological map in different planes and the different types of element combinations obtained when the absolute value of the element load in step 2) is greater than 0.5, the correlation between the elements in the rock mass, altered rock, polymetallic ore body and surrounding rock is further analyzed and verified. The element combination with obvious positive correlation is the element combination with consistent geochemical properties, and vice versa, indicating inconsistent geochemical properties. Thus, the element combination of the rock mass, altered rock, polymetallic ore body and surrounding rock in the ore deposit is determined, and the element combination type of diagenesis-metallogenesis of the ore deposit and the mineralization type it represents are clarified, and used as a qualitative indicator for evaluating the depth extension of the ore body, including the alkaline earth element combination (U, Th, Rb, Zr, Cs, Hf, REE, etc.) that can reflect the rock mass, the metallogenic element combination (Cu, Ag, Fe, Pb, Zn, Mo, W, Sn, Au, etc.) that reflects the mineralization of skarn, and the diagenetic element combination of the surrounding rock that represents the outer zone of the rock mass (Ca, Mg, Al, Si, As, Co, Ni, etc.);

[0016] Based on the geochemical anomaly-geological maps of different planes and sections in step 4), anomaly contour profiles of different factors from the rock mass to the surrounding rock are drawn, thereby obtaining a curve diagram of contour lines from the low-value anomaly area to the high-value anomaly area, and then the wavelength change is obtained through the change of the peaks and troughs of the curve diagram, thereby obtaining the change cycle of the width, length and vertical difference of the high-value anomaly area on the plane; then, the geochemical anomaly-geological maps of different planes and sections are further compared with the geological maps obtained by the existing exploration project to identify the high-value anomaly area on the geochemical anomaly-geological map The geological significance represented by the low-value anomaly area is measured on the geological map obtained by the existing exploration project, and the width, length and vertical difference of the actual rock mass, ore body and altered rock are measured. If the exposed length, width and extension distance of the shallow rock mass and ore body identified by the existing exploration project are similar to the width, length, vertical difference and change period obtained from the abnormal profiles of different factors, the width, length, vertical difference and change period of the high-value anomaly area obtained from the abnormal profiles of different factors are used as quantitative indicators for evaluating the depth extension of the ore body; finally, based on the qualitative and quantitative indicators, it is comprehensively determined whether the ore body is deep-extended;

[0017] The geological significance of determining the high-value anomaly area and the low-value anomaly area is to determine whether the high-value anomaly area represents a mineralized area or a weakly mineralized area, and whether the low-value anomaly area represents an unmineralized area or a surrounding rock area.

[0018] 2. Determine the ore body extension law based on the geochemical anomaly variation law of different elevation planes and profiles

[0019] A deep ore body extension model is constructed by comprehensively analyzing the anomaly contour maps of different elevation planes and profiles, combined with the extracted qualitative and quantitative indicators of elemental geochemical anomalies indicating the deep extension of the ore body. Based on the model and the distribution characteristics of the shallow middle section ore body, the morphology and occurrence of the deep ore body are comprehensively inferred, and the deep prospecting and positioning target area of ​​the ore deposit is delineated.

[0020] The element geochemical anomaly indicators indicating the deep extension of the ore body according to the method of the present invention include qualitative indicators of element combination anomaly, quantitative anomaly indicators of length and width of different elevations and planes, and quantitative indicators of profile height difference.

[0021] The method for judging whether the ore body extends deep in the step 5) is as follows: first, using qualitative indicators to judge whether the element combination types represented by each abnormal zone from shallow to deep have a trend of changing from low-temperature elements to high-temperature elements from shallow to deep element combinations. If so, it is considered that the deep rock mass and ore body extend to the depth; secondly, checking whether the range and number of geochemical high-value abnormal zones of the same ore body or rock body on different planes and sections have an increasing trend. If the abnormal range increases and the number increases, it is considered that the ore body continues to extend to the depth. If the abnormal range from shallow to deep decreases and the number decreases, it indicates that the ore body does not extend to the depth;

[0022] For ore bodies extending into the depths, the scope, size and change cycle of the deep concealed ore bodies are estimated based on the quantitative indicators of length, width and vertical height difference extracted from different planes. At the same time, based on the "expansion-contraction" law of shallow ore bodies and rock bodies, the pinch-out-reappearance law of ore bodies, and the lateral law of ore bodies, the possible occurrence locations of deep mineralized alteration zones and their length-width-height geometric changes are estimated.

[0023] The method of the invention can quickly identify the spatial distribution of deep ore bodies, which can not only effectively reduce the exploration cost, but also improve the prospecting efficiency of deep blind ore bodies.

[0024] Advantages and technical effects of the method of the present invention:

[0025] (1) This method can achieve qualitative or quantitative evaluation of the extension of deep concealed ore bodies;

[0026] (2) This method can effectively identify the deep occurrence rules and improve the efficiency of prospecting;

[0027] (3) This method is relatively simple and easy to apply, which can significantly shorten the deep prospecting exploration period and reduce the deep prospecting cost;

[0028] (4) This method can better guide the layout of prospecting projects and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the process of the present invention;

[0030] Figure 2 This is a diagram of the normal distribution of Co element in a copper-tin polymetallic deposit in southern Hunan;

[0031] Figure 3 This is the Varimax rotated factor loading matrix of different elements in the middle section of -136 of a copper-tin polymetallic deposit in southern Hunan;

[0032] Figure 4 This is the factor gravel map of the middle section of -136 of a copper-tin polymetallic deposit in southern Hunan;

[0033] Figure 5 This is the factor score table of different sampling points in the middle section of -136 of a copper-tin polymetallic deposit in southern Hunan;

[0034] Figure 6 This is an abnormal contour map of the middle section of -136 of a copper-tin polymetallic deposit in southern Hunan. The left picture is F 1 Factor anomaly contour map, the middle picture is F 2 Factor anomaly contour map, the right picture is F 3 Factor anomaly contour plot;

[0035] Figure 7It is the anomaly isogram of the -256 middle section of a copper-tin polymetallic deposit in southern Hunan. The left figure is the 1 anomaly isogram of Factor 2 ; the middle figure is the anomaly isogram of Factor 3 ; the right figure is the anomaly isogram of Factor

[0036] Figure 8 It is the anomaly isogram of the southern combined section of a copper-tin polymetallic deposit in southern Hunan. The upper figure is the anomaly isogram of Factor 1 and Factor 2 ; the lower figure is the anomaly isogram of Factor 3 and Factor 4 ;

[0037] Figure 9 It is the anomaly index diagram of Factor 1 (a), Factor 2 (b), Factor 3 (c), Factor 4 (d) of the -136 middle section of a copper-tin polymetallic deposit in southern Hunan. ABC in the figure is the high-value anomaly area;

[0038] Figure 10 It is the anomaly index diagram of factors in the -256 middle section of a copper-tin polymetallic deposit in southern Hunan. Among them, (a) is the anomaly diagram of Factor 1 ; (b) is the anomaly diagram of Factor 2 ; (c) is the anomaly diagram of Factor 3 ; (d) is the anomaly diagram of Factor 4 . ABCDEF in the figure represents the high-value anomaly area;

[0039] Figure 11 It is the anomaly index diagram of factors in the southern combined section of a copper-tin polymetallic deposit in southern Hunan. Among them, (a) is the anomaly diagram of Factor 1 ; (b) is the anomaly diagram of Factor 2 ; (c) is the anomaly diagram of Factor 3 ; (d) is the anomaly diagram of Factor 4 ; (e) is the anomaly diagram of Factor 6 . ABC in the figure is the high-value anomaly area;

[0040] Figure 12 It is the broken line diagram of the ore-forming element content in the southern middle sections of -136m and -256m of a copper-tin polymetallic deposit in southern Hunan;

[0041] Figure 13 It is the deep extension model diagram of the element geochemical anomaly of a copper-tin polymetallic deposit in southern Hunan. Specific implementation method

[0042] The present invention will be further described in detail below through examples. However, the protection scope of the present invention is not limited to the content described. Unless otherwise specified, the methods in the examples are all conventional methods.

[0043] Example 1: As Figure 1 shown, the method of the present invention was implemented in a magmatic hydrothermal copper-tin polymetallic deposit in southern Hunan, and good prospecting results were obtained. The specific content is as follows:

[0044] This deposit is a typical deposit in the Nanling area that is rare and has both a copper polymetallic ore-forming system related to quartz porphyry (λπ) and a tin polymetallic ore-forming system related to granite porphyry (γπ). The ore types are diverse, mainly developing three types of ore bodies: porphyry type (unformed ore body) - skarn type (W-Sn-Bi-Mo) - hydrothermal vein type (Pb-Zn-Ag). Among them, the hydrothermal vein type and skarn type ore bodies are commonly developed economic ore bodies. Many studies have shown that the formation of lead-zinc and tungsten-tin ores is related to quartz porphyry and granite porphyry respectively. The ore grade is high, and currently more than 500 economic ore bodies have been outlined. The common ore minerals are wolframite, cassiterite, molybdenite, sphalerite, galena, chalcopyrite, pyrite, pyrrhotite, magnetite, etc., and the gangue minerals are mainly fluorite, quartz, garnet, pyroxene, epidote, calcite, actinolite, vesuvianite, chlorite, wollastonite, hornblende, etc. The Cu-Pb-Zn polymetallic ore-forming system related to quartz porphyry and the W-Sn polymetallic ore-forming related to granite porphyry together constitute the magmatic hydrothermal ore-forming system of this deposit. Both types of ore-forming systems develop a metallogenic element zoning from iron (magnetite) - tungsten - molybdenum to lead - zinc - copper - silver.

[0045] I. Extraction of element geochemical anomaly indicators indicating the deep extension of the ore body

[0046] (1) Sampling and processing of mineralization-alteration-structure samples

[0047] Taking the crosscuts at the -136m and -256m levels that completely expose the ore-forming rock mass → mineralized altered body → surrounding rock as the research object, carrying out large-scale structural alteration petrography mapping at a scale of 1:200, finely depicting magmatic intrusion contact structures, fault-fold structures, etc., collecting structural rock samples with well-developed structures and close ore-forming relationships (mainly cataclastic rocks, breccias, cataclasts, fault gouges, etc.), and collecting mineralized altered rocks at locations with less developed structures to meet the requirements of the sample density for structural geochemical mapping. A total of 522 structural-geochemical samples were collected in this work. Each sample weighed 1 - 2 kg. After drying at room temperature, all samples were classified, described, and identified in detail; then, 2 main samples and 1 duplicate sample were processed from them. Then, 1 main sample was ground to 200 mesh using a ball mill and reduced to test samples; 386 representative samples (granite porphyry, quartz porphyry, skarn, altered limestone, structural rock) were selected;

[0048] (2) The tests of trace elements in the samples were completed at the Institute of Geochemistry, Chinese Academy of Sciences and the Testing Center of Northwest Nonferrous Geological Research Institute respectively. A total of 47 trace elements including Cu, Zn, As, Rb, REEs, W, Mo, Ag, Sn, Pb, Bi, etc. were analyzed. Cryptic samples were added to the test samples. When the error between the detection data of the cryptic samples and the detection data of the corresponding test samples was within the allowable error range, the detection data of the test samples was considered valid. The samples were determined by inductively coupled plasma mass spectrometry (ICP-MS, with instrument models Agilent 7700x and X-7 respectively). For every 10 samples measured, a set of standard samples (OU-6, AMH-1, GBPG-1) was measured. The analysis precision was better than 10%. 5% of cryptic samples were added to the test samples. After inspection, the test data error ≤ 10%, and the test results were valid;

[0049] (3) Geochemical data processing

[0050] The test data of 386 samples were uniformly sorted out using Excel software, and the unit was unified to 10 -6 ; after unifying the unit, the common logarithm of all data was obtained. Using SPSS software, the skewness coefficient and kurtosis coefficient of a single element were obtained. When both coefficients were less than 1 and the histogram of element content was normally distributed, it was considered to meet the normal distribution. After testing all elements, the elements that met the normal distribution were selected; taking Co as an example, it can be seen that the content distribution of cobalt element is a normal distribution curve ( Figure 2 ), so it meets the above conditions.

[0051] The contents of the selected elements were subjected to factor analysis and cluster analysis using SPSS software. Under the factor analysis module, the maximum number of factors was set to 6 and the minimum number of factors was set to 0.1. On the premise of maximum orthogonal rotation, the variance-maximum rotation factor loading matrix ( Figure 3 ) and scree plot ( Figure 4 ) of different element combinations were obtained;

[0052] When the total contribution rate of variances of different factors > 70%, the number of factors was obtained. When the absolute value of the loading > 0.5, the factor score table of the representative element combinations of different samples was obtained. Using F i to represent the factor score, where i = 1, 2, 3,... n, and then the different element combinations in different factors were obtained; in this embodiment, when the cumulative variance contribution rate of the -136m middle section reached 75.99%, 6 composite factors were obtained. F 1 was Co, Ga, Ge, Rb, Zr, Cs, Hf, Th, U, LREE, HREE; F 2 was Cu, Zn, As, Ag, Cd, Sb, Pb; F 3 was -V, -Cr, -Ni; F 4are - Sr, W, Mo, Sn, Bi; F 5 are Cu, (Co); F 6 are As, (Sb). Among them, F 1 represents the petrogenetic element combination of the ore - forming rock mass, mainly enriched in feldspar and mica phenocrysts; F 2 represents the medium - low - temperature hydrothermal vein - type lead - zinc ore - forming element combination, mainly composed of sphalerite, galena, pyrite and pyrrhotite, associated with useful components such as granular arsenopyrite, droplet - shaped stibnite and silver; F 3 represents the element combination related to pyrite - pyrrhotite - magnetite mineralization; F 4 represents the high - temperature element combination during skarn mineralization; F 5 represents the element combination mainly composed of chalcopyrite mineralization; F 6 represents the element combination mainly composed of arsenopyrite, and at the same time obtains the factor score values at different sampling positions ( Figure 5 );

[0053] When the cumulative variance contribution rate of the - 256 middle section reaches 72.46%, a total of 5 composite factors are obtained. F 1 are Co, Ga, Rb, Zr, Cs, Cs, Hf, W, Th, U, LREE, HREE; F 2 are - Cu, - Zn, - As, - Sb, - Pb, - Ag, - Cd; F 3 are Ga, Ge, W, Mo, Sn, Bi; F 4 are - V, - Cr. F 5 The factor is meaningless. Among them, factor 1 represents the alkaline earth element combination, representing the petrogenetic elements related to the ore - forming rock mass; factor 2 represents the medium - low - temperature hydrothermal vein - type lead - zinc ore - forming element combination, and associated useful components such as granular arsenopyrite, droplet - shaped stibnite, chalcopyrite can be seen under the microscope; factor 3 represents the high - temperature element combination during skarn mineralization; factor 4 represents pyrite - pyrrhotite mineralization. When the cumulative variance contribution rate obtained from the combined section of the middle section in the southern part of the mining area reaches 77.72, a total of 5 composite factors are obtained. F 1 are Sc, Rb, Zr, Nb, Cs, Hf, Th, U, LREE, HREE; F 2 are - Cu, - Zn, - As, - Ag, - Cd, - Sb, - Pb; F 3 are Be, Ge, Mo, Sn, W, Bi, - Sr; F 4 are V, Cr, Ni; F 5 is Co, F 6Meaningless. Among them, factor 1 represents the diagenetic element combination related to the ore-forming rock body; factor 2 represents the lead-zinc ore-forming element combination of medium-low temperature hydrothermal vein type; factor 3 represents the high-temperature element combination in the mineralization process of skarn; factors 4 and 5 may represent pyrite-pyrrhotite-magnetite mineralization alteration.

[0054] The coordinates and factor scores of each sample in the -136m, -256m middle and southern joint sections were organized in Excel, and the data of different factor scores with spatial coordinates were imported into the contour drawing software Mapgis to draw the element combination anomaly contour maps of different planes and sections. The anomaly contour map of the -136m middle section is shown in Figure 6 , -256 mid-section abnormal contour map will Figure 7 ; The anomaly contour map of the southern joint profile is shown in Figure 8 shown.

[0055] (4) Drawing of plane and section anomaly contour maps

[0056] In determining the abnormal lower limit, we first remove some high values ​​in the test data, and then calculate the abnormal lower limit based on the element grade (e.g. W: 800×10 -6 , Sn: 1000×10 -6 , Mo:300×10 -6 ,Bi:2000×10 -6 , Cu: 2000×10 -6 , Pb: 3000×10 -6 , Zn: 5000×10 -6 Then, after multiple eliminations according to the extremely high value greater than three times the standard deviation, the lower limit value of each element was obtained (e.g. W: 95.95×10 -6 , Sn:95.52×10 -6 , Mo:34.07×10 -6 ,Bi:43.05×10 -6 , Cu: 114.52×10 -6 , Pb:477.59×10 -6 , Zn: 541.81×10 -6 );

[0057] According to the obtained lower limit values ​​of each element, the high-value anomaly area and low-value anomaly area in the -136m, -256m middle section and southern joint section are circled in the element combination anomaly contour map of different planes and sections in step (3). The -136m middle section is analyzed by F 1 The factor score value can be used to identify two high-value abnormal areas and one low-value abnormal area ( Figure 9 a); F 2The factor score values can delineate 3 high-value anomaly areas and 2 low-value anomaly areas ( Figure 9 b); F 3 The factor score values can delineate 3 high-value anomaly areas and 2 low-value anomaly areas ( Figure 9 c); F 4 The factor score values delineate a total of 3 anomaly areas and 2 low-value anomaly areas ( Figure 9 d). F 5 and F 6 The factors are Cu and As respectively, and their geological significance is not clear, so they are not studied in this embodiment. -256m middle section F 1 The factor score of the alkaline earth element combination delineates 4 high-value anomaly areas and 2 low-value anomaly areas ( Figure 10 a); F 2 The factor represents the anomaly of the middle-low temperature metallogenic element combination, and a total of 6 high-value anomaly areas and 3 low-value anomaly areas are delineated; F 3 The high-temperature metallogenic elements represented by the factor can delineate 3 high-value anomaly areas and 3 low-value anomaly areas ( Figure 10 c), F 4 The factor delineates a total of 4 high-value anomaly areas and 3 low-value anomaly areas ( Figure 10 d). Vertically, Figure 11 It shows the F with obvious geological significance 1 and F 2 and F 3 and F 4 and F 6 Factor score isoline anomaly - geological map, using the combined elements of the F 1 factor can delineate 2 high-value anomaly areas and 3 low-value anomaly areas ( Figure 11 a); F 2 The factor representing the middle-low temperature metallogenic element combination can delineate 3 high-value anomaly areas ( Figure 11 b), F 3 The factor element combination delineates a total of 3 high-value anomaly areas and 2 low-value anomaly areas ( Figure 11 c), using the F 4 factor combination elements V, Cr, Ni anomalies to delineate a total of 3 high-value anomaly areas and 2 low-value anomaly areas ( Figure 11 d), the F6 factor combination elements delineate a total of 3 obvious high-value anomaly areas ( Figure 11 e).

[0058] (5) Significance of element geochemical anomalies

[0059] Overlay the element combination anomaly isoline maps of the -136m, -256m middle sections and the southern combined section with the geological map to obtain the geological - element combination anomaly diagram; taking -136m as an example to illustrate the distribution characteristics and geological significance of the anomalies, -136m middle section F 1 factor (Figure 9 a) reflects the trace element combinations representative of rock masses such as granite porphyry and quartz porphyry. Using the factor score values, two anomalous areas can be delineated. The center of anomaly A is located on the west side of this midsection, and the connection of the high-value areas as a whole shows a nearly SN or NE-SW trending distribution; anomaly B is located on the SE side. The overall shapes of anomalies A and B are basically the same as those of quartz porphyry and granite porphyry, and are consistent with the strike of the main faults f 1 and f 3 in the NNE direction. The low-value areas spread out to both the EW sides and the SW side and are not closed, suggesting the characteristics of emplacement of the rock mass along the main fault.

[0060] F 2 factor is a combination of medium- and low-temperature ore-forming elements, and three anomalous areas can be outlined ( Figure 9 b)). The anomalies are all distributed in the concave parts on the side of the rock mass or rock branch, and have an annular structure with the factor score values gradually decreasing from the center of the ore body to the surrounding rocks on both sides, decreasing gradually towards the side of the ore-forming rock mass. The high-factor score parts are all massive galena-sphalerite-pyrite-pyrrhotite ore bodies.

[0061] F 3 factor is a combination of -V, -Cr, -Ni elements, and three anomalous areas can be outlined ( Figure 9 c)). The overall strike of the high-value anomalous area is SN. Overlaying with the geological plan view, it can be seen that the center of the anomaly is generally located within the alteration zone of the ore-forming rock mass and its adjacent side. The anomaly gradually weakens towards the E and W sides. Based on the actual geological characteristics, the low-value areas are all grayish-black weakly altered fine-grained limestone without lead-zinc mineralization, and the high-value areas generally correspond to strongly altered mineralized limestone and skarn. Pyrite, pyrrhotite, and magnetite are relatively developed in these rocks. This element combination generally appears in ultrabasic and basic rocks, and such rocks are basically not developed in this deposit. Therefore, it is speculated that the anomaly may be caused by minerals such as pyrite, pyrrhotite, and magnetite.

[0062] F 4 factor represents a combination of high-temperature ore-forming elements related to W-Sn-Mo, and a total of three anomalous areas are outlined ( Figure 9 d)). Anomaly A is located in the concave part of quartz porphyry and basically overlaps with anomaly area F1. Anomaly B is located on the SE side, with the strongest anomaly intensity and range. Anomaly area C is located on the NE side. Combining with the actual geological characteristics, it can be seen that these anomalies are all located in the strongly developed parts of skarn. The skarn alteration on the SE side is extremely strong and the outcropping area is relatively wide. Therefore, the anomaly in area B is the strongest, and the skarnization alteration intensity and range in areas A and C are both weak, so the anomalies are also relatively weak.

[0063] Compared with the -136m midsection, the number of anomalies in the -256m midsection has increased significantly. Using the anomaly distribution diagrams obtained from different element factor combinations ([[]] Figure 10 ). Based on F 1Five anomaly areas delineated by the combined factor scores of alkaline earth elements ( Figure 10 a) are all located within the ore-forming rock mass, showing good coincidence with the rock mass range. The anomaly is the strongest on the SE side, suggesting that the rock mass may be more developed on the SE side. The connection line of the high-value anomaly areas is consistent with the strike of the main fault, trending nearly SN. F 2 The factor represents the anomaly of medium- and low-temperature ore-forming element combinations. This anomaly is relatively scattered, and the six anomaly areas are distributed on the north side, middle and south side of this interruption ( Figure 10 b), and the anomaly connection line trends SN. Geological characteristics indicate that F 2 The factor anomalies are all distributed in the strongly altered limestone beside the rock mass. Controlled by the morphology of the rock mass, massive galena-sphalerite-pyrite-pyrrhotite ore bodies are relatively developed. The anomaly has an annular structure with the factor score values gradually decreasing from the center of the ore body to the surrounding rocks on both sides; the situation in the middle anomaly area is relatively consistent with that in the north, and outside the rock mass at the center position of the south anomaly area, it extends from SSW to NNE and the element combination is more enriched on the NNE side, suggesting that the migration direction of the ore-forming fluid may be from SSW to NNE. F 3 The high-temperature ore-forming elements represented by the factor can delineate three high-value areas ( Figure 10 c), which are mainly distributed in the fracture structures and skarn contact zones beside quartz porphyry, granitic porphyry rock masses or dikes, especially at the concave and convex parts of the rock mass. At the same time, F 3 The factor has a negative correlation with F 2 factor. F 4 The element combination of the factor is completely consistent with -136m, and a total of 4 anomaly areas are delineated ( Figure 10 d) The distribution range is also located in the altered zone adjacent to the rock mass, and pyrite, pyrrhotite, etc. are relatively developed in this zone. F 1 The factor anomaly area has a negative correlation with F 3 factor, indicating that the mineralization is closely related to the magmatic rock mass.

[0064] Vertically, for the vertical change law of the southern tectono-geochemical anomaly, the combined elements of the F 1 factor

[0065] Sc-Zr-Nb-Rb-Cs-Ba-Hf-Ta-Th-U-LREE-HREE, which is a combined alkaline earth element, representing the trace element combined factor of rock masses such as granitic porphyry and quartz porphyry. 2 anomaly areas ( Figure 11a) All are located beside and within the rock mass. The west side and the east side represent the quartz porphyry and granite porphyry rock masses respectively. The anomaly boundary basically corresponds to the spatial form of the rock mass. In the deep middle section (-296m middle section), the anomaly range on the quartz porphyry side increases significantly in both size and width. The plunge direction of the connecting line between the rock mass at -136m middle section is SE. The high-value area of the positive anomaly area on the east side is the eastern area of -176m middle section. The anomaly opens towards the E side, suggesting that there may be a corresponding high-value area on the SE side in the deep part. The position where the zero anomaly isopleth protrudes towards the negative anomaly is the Shidengzi limestone. Corresponding to the weakly deformed and weakly altered lithofacies belt, the mineralization effect is generally average.

[0066] F 2 The factor represents a medium-low temperature ore-forming element combination - Cu - Zn - Ag - Cd - Sd - Pb. Vertically, there are three negative anomaly areas ( Figure 11 b). All are located within the altered limestone areas on both sides of the rock mass. The high-value area of the west-side anomaly diverges towards the SW side. The middle anomaly area plunges towards the SE side in a ring shape. The central position of the south-side anomaly area is in close contact with the magmatic rock mass and diverges towards the SW side in the same way as the west-side anomaly area. The anomaly ranges in the middle and south are significantly smaller than those on the west side. The overall anomaly range of the high-value area increases towards the deep part, indicating that the lead-zinc-copper mineralization in the Shidengzi Formation limestone in the deep part is stronger. This is consistent with the vertical alteration zoning law. The anomaly distribution trend indicates that the ore-forming fluid migrates with the rock mass as the center and migrates towards the surrounding rocks on both sides, and the mineralization gradually weakens away from the rock mass. The negative value area F 1 The range of the negative value area fits well, further indicating that the mineralization effect is generally average. Based on the above characteristics, it is indicated that the Cu-Zn-Ag-Pb mineralization is closely related to the ore-forming rock mass.

[0067] F representing the high-temperature skarn-type Be-Ge-Mo-W-Sn-Bi ore-forming element combination 3 has two anomaly areas (western anomaly and eastern anomaly) in the area adjacent to the ore-forming rock mass ( Figure 11 c). The middle anomaly area has one anomaly center, and the anomaly shape is basically the same as the contact shape between the granite porphyry and the surrounding Shidengzi Formation limestone. The south-side anomaly area consists of two anomaly centers, both of which are located within the skarn zone. The overall strike is NNW-SSE and diverges towards the SE direction, reflecting that the occurrence of the ore body should be trending SE, generally consistent with the contact metamorphic zone between the granite rock mass and the surrounding Shidengzi Formation limestone, which is a favorable area for the formation of skarn-type ore bodies, suggesting good ore-forming potential in the deep part.

[0068] Using the F 4 factor combination elements V, Cr, Ni anomalies, a total of three anomaly areas are outlined ( Figure 11d), Most of the centers of the abnormally high value areas are located in the limestone of the Shidengzi Formation and some ore-forming rock masses. Pyritization and pyrrhotitization alterations are usually relatively common in these abnormal distribution areas. Therefore, it is speculated that this element combination comes from pyrite alteration. The plunge directions are all to the east side, and the anomalies in the deep and shallow parts are not closed, indicating that the anomalies from the shallow part to the deep part are consistent with the dip directions of the rock mass and the structure. F 5 The factor represents pyritization, etc. in the mining area, and its relationship with mineralization is not obvious. Therefore, it is not the object of this study.

[0069] F located at the sunken part where the quartz porphyry contacts the limestone 6 The factor combination element Cu anomaly outlines three anomaly areas in total ( Figure 11 e), The anomaly distribution is consistent with the actual geological characteristics and is the main output location of the Cu-Pb-Zn ore bodies. The overall dip is to the east, and the anomaly on the side of the granite porphyry is not obvious or very weak. Therefore, the Cu mineralization is directly controlled by the quartz porphyry, and the output locations of the ore bodies are mostly located in the sunken parts of the rock mass.

[0070] (6) Extraction of quantitative indexes for the deep extension of element geochemical anomalies

[0071] From the geological-trace element profile from the rock mass to the ore-hosting wall rock ( Figure 12 ), it can be seen that the contents of W, Sn, Bi, and Mo are significantly higher than those of Cu and Ag. W, Sn, Bi, and Mo are the indicator elements of skarn-type magnetite tungsten molybdenum ore bodies. The contents of W and Mo are relatively high in the rock mass (the W content is as high as 3.01×10 -3 , and the Mo content is as high as 1.32×10 -3 ), reaching the peak values in the magnetite (tungsten tin) ore-bearing garnet skarn zone (Ⅱ-1) and the tungsten molybdenum-pyrrhotite-bearing garnet skarn zone (Ⅱ-2), and decreasing in zone Ⅲ; the contents of Sn and Bi elements are relatively high in the skarn (the Sn content is as high as 7.12×10 -3 , and the Bi content is as high as 4.12×10 -3 ), and gradually decreasing to the recrystallized limestone zone; the Cu element content is relatively high in the skarn on the side close to the wall rock; the Pb and Zn contents are relatively high in the skarn on the side close to the wall rock (Ⅱ-2) and in the crystalline limestone (Ⅲ) (the Pb content is as high as 5.62×10 -2 , and the Zn content is as high as 1.39×10 -1 ); the Ag content is relatively low (the content change ranges from 0.1×10 -6 to 1.22×10 -4 ), and the overall change trend is not significant.

[0072] Therefore, from the rock mass → skarn → wall rock, the contents of W, Sn, Bi, and Mo first gradually increase to Zone III and then gradually decrease. The Cu content is high in the lead-zinc mineralized skarn, the Pb and Zn contents reach their peaks in Zone III, and the Ag content shows basically no change. The combination of ore-forming elements has a changing pattern from high-temperature W, Sn, Bi, Mo → medium-high-temperature Cu, Pb, Zn → medium-low-temperature Pb-Zn-Ag, reflecting that the element combination shows a changing process from high temperature to low temperature on the plane, and this changing pattern is consistent with the alteration-mineralization zone phenomenon.

[0073] Secondly, combining the above characteristics and geological reality, the anomaly indicators are constructed as follows:

[0074] Extraction of qualitative indicators for element combination anomalies: Element clustering analysis can effectively divide ore-forming elements into two types, which have a good correspondence with the ore-forming stages, showing: (1) The skarn-type high-temperature element class, mainly composed of W, Sn, Mo, and Bi. However, no obvious high-temperature element minerals crystallize in the shallow-middle section. In the middle-deep section, magnetite, molybdenite, scheelite, cassiterite and other metal minerals often develop in the skarn, corresponding to the above high-temperature elements, and sphalerite, galena, pyrrhotite and other metal minerals are superimposed spatially; (2) The hydrothermal vein-type medium-high-temperature element class, mainly with element anomalies of Cu, Pb, Zn, Co, Ni, Cd, Sb, As, Ag. Macroscopically, hydrothermal minerals such as sphalerite, galena, pyrite, chalcopyrite, pyrrhotite, arsenopyrite, bismuthinite correspond to them. They have a good correspondence with the polymetallic ore-forming system. In addition, element clustering analysis also indicates that from the shallow part to the deep-middle section, the element anomalies are obvious in the shallow part with a medium-high-temperature element combination, mainly dominated by hydrothermal vein-type mineralization; in the middle part, high-temperature elements and medium-high-temperature elements have superimposed ore formation, indicating that high-temperature ore formation and medium-high-temperature ore formation are relatively developed; while the combined double-grouping effect of symbiotic elements in the deep part is more obvious (taking the -256m middle section as an example). Thus, it can be seen that from the shallow part to the deep part, the ore-forming system has a relatively developed shallow hydrothermal vein-type ore-forming subsystem, and the coexistence phenomenon of the hydrothermal vein-type and skarn-type subsystems is more developed with increasing depth. Thus, it can be seen that from the shallow part to the deep part, the ore body extends deepward and gradually evolves into an ore body mainly composed of high-temperature elements.

[0075] Draw the anomaly isoline profile of different factors from the rock mass to the wall rock ( Figure 9 , Figure 10 , Figure 11 the curve graph on the left or right side of the anomaly map) Extraction of plane anomaly quantitative indicators: On the plane, based on F 1 , F 2 and F 3From the factor isopleth profile, it can be obtained that the length of the half-wavelength from the high-value anomaly area to the low-value anomaly area ranges from 350 to 400 m, and the width ranges from 120 to 400 m, indicating that the width and length ranges of the mineralized alteration zone are 350 - 400 m and 120 - 400 m respectively. The variation law of the high-temperature skarn ore-forming elements and the medium- and low-temperature ore-forming elements is consistent with the wavelength change of the rock mass, confirming that the geometric change part of the rock mass is the main enrichment part of the ore-forming elements.

[0076] Extraction of quantitative indexes of profile anomalies: Figure 11 The shown element geochemical anomaly - geological map shows that vertically, the half-wavelength of the high-value anomaly area ranges from 50 to 70 m, and the high-temperature W-Sn ore bodies are mainly hosted in the part where the rock mass changes from convex to concave. Therefore, the vertical difference of the ore bodies is about 140 m, and it has a periodic variation law. At the same time, based on the measurement of the vertical difference of the main ore bodies in the shallow geological profile, the extension distance is about between 100 and 145 m, which is nearly consistent with the vertical difference obtained from the deep anomaly. Therefore, the element anomaly combination distribution in the plane and vertical directions obtained by factor analysis has an equally spaced distribution characteristic. Without considering the geostatic-geothermal gradient, vertically, the wavelength of the "swelling - shrinking" of the rock mass is about 100 - 140 m. The swelling part of the rock mass is the enrichment area of high-temperature W-Sn-Mo-Bi elements, and low-temperature Cu-Pb-Zn-Sb anomalies are developed in the adjacent limestone strata ( Figure 11 ). According to the vertical variation of the element combination, it is speculated that there are multiple peak positions in the deep part, such as: -346 m to -406 m, -436 to -526 m, where the rock mass gradually swells ( Figure 13 ), thus confirming that the ore body continues to extend deepward and has a law of swelling and shrinking.

[0077] The geological significance of different middle sections and profiles has been elaborated in detail above and will not be repeated here. Based on the existing middle section and profile data, the outcrop lengths and widths of the ore bodies and rock masses at the -136m and -256m middle sections, as well as the extension distances of the rock masses and ore bodies on the 109 exploration line profile, etc., are further measured. Among them, at the -136 middle section, the outcrop width of the quartz porphyry is between 312 - 420m, the length is 400 - 600m, and the thickness of the Cu-Pb-Zn polymetallic ore body it controls ranges from 1 - 25m. The outcrop length of the granitic porphyry is about 500m, and the width is between 80 - 160m. At the -256 middle section, the outcrop width of the quartz porphyry is between 202 - 300m, the length is 400 - 600m, the outcrop length of the granitic porphyry is about 700m, and the width is 130m. The polymetallic ore body in the skarn with iron-tungsten-molybdenum mineralization at the contact zone of the granitic porphyry has a strike length of 800 - 1000m, a width of 60 - 400m, and a dip extension >1000m. The occurrence elevation of the ore body is 100 - -760m, the thickness of the ore body is 12 - 336.05m, with an average of 86m. Vertically, from the shallow part to the deep part of the exploration line profile, the expansion and contraction period of the rock mass is 120 - 140m, and the vertical difference of the ore body at the depression is about 70 - 90m. These actual distances are basically consistent with the lengths and widths obtained from the aforementioned anomalies. This further confirms that the deep mineralized alteration bodies may have characteristics similar to those in the plane and profile.

[0078] II. Determining the Deep Extension of the Ore Body Based on the Variation Laws of Geochemical Anomalies of Plane and Profile Elements at Different Elevations

[0079] Based on the study of the typical characteristics of the ore deposit, integrating information indicating the deep extension of the ore body, such as the metallogenic type of the polymetallic metallogenic system, mineralization alteration zoning, and metallogenic physicochemical conditions, the variation trends of the shapes, attitudes, and scales of the metallogenic rock masses and structure controlling the rock and ore towards the deep part are inferred; integrating the comprehensive indicators of structural geochemical anomalies indicating deep polymetallic mineralization, so as to comprehensively distinguish the extension of the ore body ( Figure 13 ).

[0080] Integrating the geological characteristics of the ore deposit, the deep extension characteristics of the ore-controlling structure, the vertical zoning of the metallogenic rock mass and mineralization alteration, the information of structural geochemical anomalies, and the vertical variation laws of trace elements of characteristic minerals, and combining with the exploration results of the shallow middle sections in the mining area, it is considered that the deep magmatic intrusion contact structure and the vertical extension of the polymetallic ore body have an equidistant distribution characteristic.

[0081] 1) Vertically, the height difference change period of the metallogenic rock body's shape and occurrence is 100 - 140 m (λ ≈ 100 - 140 m, 1 / 2λ ≈ 50 - 70 m), showing a "swelling - shrinking" change, and its mineralized alteration bodies also show corresponding periodic change rules. Therefore, based on this change rule, the shape and occurrence of the metallogenic rock body and mineralized alteration bodies below -400 m can be inferred, and the possible occurrence positions and geometric (length - width - height) changes of the mineralized alteration zone can be speculated successively towards the deep part;

[0082] 2) The concave - convex parts of the contact zone structure are favorable spaces for mineralization. Based on the co - variation rule between the abnormal combination of profile elements and the concave - convex changes of the rock body, the main ore bodies are distributed in the conversion part of the metallogenic rock body from concave (wave peak) to convex (wave valley). The vertical difference of the main ore bodies is 25 - 35 m (1 / 4λ ≈ 25 - 35 m); combined with the plane distribution characteristics of the ore bodies, the length of the main ore bodies is 130 - 150 m (1 / 2λ ≈ 130 - 150 m);

[0083] 3) Based on the outcrop width of the ore bodies on the plane, the widths of the hydrothermal vein - type ore bodies and skarn ore bodies can be inferred to be 60 m - 70 m.

Claims

1. A method for determining the deep extension of ore bodies in magmatic hydrothermal polymetallic deposits using elemental geochemical anomalies. It is characterized in that Proceed as follows:

1. Extracting element geochemical anomaly indicators that indicate the depth of the ore body 1) Select several exploration lines and prospecting veins on a certain magmatic hydrothermal polymetallic deposit to carry out large-scale structural-alteration petrographic mapping, and collect structural rock samples with well-developed fractures and fissures and close relationship with mineralization at a certain interval. The samples include cataclase, breccia, granular rock, and fault gouge. These structural rock samples are classified, described and identified in detail, and then the collected samples are processed and reduced into test samples; 2) Detect the trace element content of the reduced test sample, and sort out all valid test data, take the common logarithm of all valid test data, and use statistical analysis software to obtain the skewness coefficient and kurtosis coefficient of a single element. When both coefficients are less than 1, it is considered to satisfy the normal distribution. After all elements are tested, select the elements that satisfy the normal distribution; The content of the selected elements was subjected to factor analysis and cluster analysis using statistical analysis software. In the factor analysis module, the maximum number of factors was set to 5 or 6, and the minimum number of factors was set to 0.

1. Under the premise of maximum orthogonal rotation, the factor table and scree plot of different element combinations were obtained; The number of factors is obtained when the total contribution rate of variances of different factors > 70%. When the absolute value of the loading > 0.5, a factor score table of the representative element combinations of different samples is obtained, with F i representing the factor score, where i = 1, 2, 3, … n, and then different types of element combinations in different factors are obtained; Then, the spatial coordinates of the samples at different sampling positions are counted and different factor scores, namely X, Y, and F, are assigned to them. i The data with different factor scores and spatial coordinates are imported into contour drawing software to draw contour maps of element combination anomalies for different planes and profiles. 3) Determine the lower limit of trace element anomalies, specifically, first remove the maximum value in the effective content detection data, and after multiple removals according to the extremely high value greater than three times the standard deviation, the lower limit of anomalies is the average value of the content plus two times the standard deviation. If the lower limit of anomalies of some elements is still higher than the content of the corresponding elements in the unaltered rock through calculation, the element contents are arranged from small to large, and the value at the one-third position is taken as the lower limit of anomalies; according to the lower limit of anomalies, the high-value anomaly areas and low-value anomaly areas of different factors are circled in the element combination anomaly contour map in step 2), wherein the high-value anomaly refers to the data being higher than the lower limit of anomalies; 4) superimposing the element combination anomaly contour maps of different planes and sections in step 2) with the geological maps of different planes and sections of the ore deposit obtained after mapping in step 1) according to the corresponding spatial coordinates, and obtaining the geochemical anomaly-geological maps of different planes and sections, and obtaining the distribution characteristics of anomalies of different factors from the maps, including the number, range, shape and size of anomalies; combining the geological facts of different planes and sections, determining the geological significance of mineralization or weak mineralization represented by the high-value anomaly area, and the geological significance of unmineralized or surrounding rock represented by the low-value anomaly area; 5) Based on the geochemical anomaly-geological map in different planes and the different types of element combinations obtained when the absolute value of the element load in step 2) is greater than 0.5, the correlation between the elements in the rock mass, altered rock, polymetallic ore body and surrounding rock is further analyzed and verified. The element combination with obvious positive correlation is consistent with the geochemical properties, and vice versa indicates inconsistent geochemical properties. Thus, the element combination of the rock mass, altered rock, polymetallic ore body and surrounding rock in the ore deposit is determined, and the element combination type of the diagenesis-mineralization of the ore deposit and the mineralization type it represents are clarified, and used as a qualitative indicator for evaluating the depth extension of the ore body, specifically including the alkaline earth element combination that can reflect the rock mass, the mineralization element combination of skarn mineralization and the diagenetic element combination of the surrounding rock outside the rock body; Based on the geochemical anomaly-geological maps of different planes and sections in step 4), anomaly contour profiles of different factors from the rock mass to the surrounding rock are drawn, thereby obtaining a curve diagram of contour lines from the low-value anomaly area to the high-value anomaly area, and then the wavelength change is obtained through the change of the peaks and troughs of the curve diagram, thereby obtaining the change cycle of the width, length and vertical difference of the high-value anomaly area on the plane; then, the geochemical anomaly-geological maps of different planes and sections are further compared with the geological maps obtained by the existing exploration project to identify the high-value anomaly area on the geochemical anomaly-geological map The geological significance represented by the low-value anomaly area is measured on the geological map obtained by the existing exploration project, and the width, length and vertical difference of the actual rock mass, ore body and altered rock are measured. If the exposed length, width and extension distance of the shallow rock mass and ore body identified by the existing exploration project are similar to the width, length, vertical difference and change period obtained from the abnormal profiles of different factors, the width, length, vertical difference and change period of the high-value anomaly area obtained from the abnormal profiles of different factors are used as quantitative indicators for evaluating the depth extension of the ore body; finally, based on the qualitative and quantitative indicators, it is comprehensively determined whether the ore body is deep-extended; 2. Determine the ore body extension law based on the geochemical anomaly variation law of different elevation planes and profiles A deep ore body extension model is constructed by comprehensively analyzing the anomaly contour maps of different elevation planes and profiles, combined with the extracted qualitative and quantitative indicators of elemental geochemical anomalies indicating the deep extension of the ore body. Based on the model and the distribution characteristics of the shallow middle section ore body, the morphology and occurrence of the deep ore body are comprehensively inferred, and the deep prospecting and positioning target area of ​​the ore deposit is delineated.

2. The method for determining the deep extension of the ore body of a magmatic hydrothermal polymetallic deposit by using element geochemical anomalies according to claim 1, Features: The geological significance of determining the high-value anomaly area and the low-value anomaly area is to determine whether the high-value anomaly area represents a mineralized area or a weakly mineralized area, and whether the low-value anomaly area represents an unmineralized area or a surrounding rock area.

3. The method for determining the deep extension of the ore body of a magmatic hydrothermal polymetallic deposit by using element geochemical anomalies according to claim 1, Features: The discriminant method for whether the ore body extends deeply in step 5) is as follows. First, use qualitative indicators to determine whether there is a change trend of element combination types represented by each abnormal area from shallow to deep, from low-temperature elements to high-temperature elements. If so, it is considered that the deep rock mass and ore body extend deepward. Second, check whether the range and quantity of geochemical high-value abnormal areas of the same ore body or rock mass increase on different planes and sections. If the abnormal range increases and the quantity becomes larger, it is considered that the ore body continues to extend deepward. If the abnormal range shrinks and the quantity decreases from shallow to deep, it indicates that the ore body does not extend deepward. For the ore body extending deepward, based on the extracted quantitative indicators of length, width, and vertical elevation difference on different planes, speculate on the range, size, and change period of the deep buried ore body. At the same time, according to the "swelling-shrinking" law of shallow ore bodies and rock masses, the law of pinching out-reappearance of ore bodies, and the law of plunge of ore bodies, speculate on the possible occurrence positions of deep mineralized alteration zones and their geometric changes in length-width-height.

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