Mineral prospecting prediction method based on compound rock mass anatomical porphyry-skarn composite mineralization system

Abstract

The invention relates to the technical field of mineral resource prospecting exploration, in particular to a prospecting prediction method based on a compound rock mass anatomy porphyry-skarn composite mineralization system. The control factors and formation mechanism of the ore deposit are clarified, and the deep earth dynamics process of porphyry mineralization development is disclosed. Through typical ore deposit fine dissection, the space-time structure characteristics of mineralization in different structural evolution stages are discussed; according to the method, mineral in-situ micro-area surface scanning and sulfide isotope in-situ tracing technologies are utilized to determine occurrence forms of metallogenic elements, restrain activation migration behaviors of microelements, find out sources of metallogenic metal substances, reveal a superposition metallogenic development mechanism and provide theoretical basis and technical support for prospecting exploration.

Description

Technical Field

[0001] The present invention relates to the technical field of prospecting and exploration of mineral resources, and in particular to a prospecting prediction method based on a composite rock mass dissection of a porphyry-skarn composite mineralization system. Background Art

[0002] Superimposed mineralization is a manifestation of complex geological processes, often resulting in complex ore deposit compositions and structures. It is also a key factor in the formation of large and rich ores. Superimposed deposits are widespread in nature, and most are formed over a long period of geological history, resulting in the superposition of multiple mineralization stages. From a geodynamic perspective, the formation of large and super-large deposits invariably bears the imprint of multiple superimposed mineralization events. Numerous studies have revealed that multi-stage crust-mantle interaction or composite orogeny, deep driving, multi-factor coupling, and critical transitions are key factors controlling the formation of large and super-large deposits, such as porphyry, magmatic, or low-temperature hydrothermal deposits.

[0003] For a long time, the superimposed mineralization of deposits associated with magmatic intrusions was neglected. Most deposits, characterized by the superposition of the same geological process in different ways or at different spatial locations, exhibit porphyry-skarn composite mineralization systems. In recent years, research on superimposed mineralization has made significant progress. Numerous researchers have conducted comprehensive and in-depth studies on the superimposed mineralization of the Fe-Cu-Au polymetallic metallogenic belt in the middle and lower Yangtze River, the porphyry Cu deposits in the Central Asian tectonic domain, multi-stage hydrothermal mineralization in the Jiaodong region, the Sanjiang Tethys metallogenic domain in southwestern China, the Gangdese porphyry Cu-Mo metallogenic belt in Tibet, and the Langshan metallogenic belt. The superimposed mineralization of the Laochang polymetallic deposit in Yunnan Province has been summarized as "co-topic superposition of two metallogenic systems," providing a paradigmatic example for understanding superimposed mineralization. Furthermore, studies of the Zhongdian porphyry Cu belt in northwestern Yunnan have preliminarily established that the Zhongxun porphyry Cu belt is superimposed on a Late Cretaceous porphyry Mo-Cu mineralization system in a north-south direction, representing a typical superimposed composite mineralization belt. Previous research has systematically investigated the composition of the early and late tectonic-magmatic-hydrothermal mineralization systems in the Zhongdian area of ​​Yunnan Province, particularly the Late Triassic porphyry Cu mineralization system. While research on Late Cretaceous Mo-Cu deposits is ongoing and in-depth, our understanding of superimposed mineralization remains limited. A clear understanding of the co-localization of mineralization at the same deposit scale under different tectonic settings and dynamic conditions remains lacking. This hinders accurate interpretation of the mineralization processes within the porphyry-skarn composite mineralization system, hindering prospecting and prediction efforts in the region. Summary of the Invention

[0004] The purpose of the present invention is to provide a prospecting prediction method for porphyry-skarn composite mineralization system based on complex rock mass dissection. Through the systematic combing of crust-derived magmatic activity and porphyry Mo-Cu mineralization events formed by Late Cretaceous collisional orogeny and post-orogenic extension, the controlling factors and formation mechanism of the ore deposits are clarified, and the deep geodynamic process of the development of porphyry mineralization is revealed. Through the detailed dissection of typical ore deposits, the spatiotemporal structural characteristics of mineralization in different tectonic evolution stages are explored; the magma intrusion age is determined by combining microscopic observation and U-Pb dating, and the mineralization stages are divided; the in-situ micro-area analysis and testing of minerals and the in-situ tracing technology of Hf isotopes are used to determine the occurrence form of mineralization elements, constrain the activation and migration behavior of trace elements, identify the source of mineralization metal materials, reveal the superimposed mineralization development mechanism, and provide theoretical basis and technical support for prospecting and exploration.

[0005] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0006] A prospecting prediction method based on the composite rock mass anatomy of a porphyry-skarn composite mineralization system comprises the following steps:

[0007] S1: Data collection and collation: Systematically collect the results of mineral geological surveys in the study area, comprehensively analyze the regional tectonic evolution and metallogenic geological background, and sort out the spatial distribution characteristics, metallogenic conditions and ore-controlling factors of the Late Cretaceous ore-bearing porphyry bodies;

[0008] S2: Field investigation and sampling: Based on preliminary geological and mineral research, representative blocks are selected as dissecting windows. The kinematic characteristics of the geological bodies are analyzed using structural analysis methods. The contact relationship of the porphyry intrusion is determined in combination with borehole logging. Rock and mineral samples are systematically collected from the porphyry-skarn contact zone, alteration zones, and vein intersections.

[0009] S3: Indoor analysis test:

[0010] Petrographic and mineralogical analysis: Identify mineral intergrowth relationships and alteration sequences through scanning electron microscope backscatter images, and divide mineralization stages;

[0011] Garnet and zircon U-Pb dating: LA-ICP-MS is used to determine the diagenetic age of skarns and igneous rocks, systematically determining the period of magma intrusion in the mining area;

[0012] Analysis of major and trace elements in rocks: ICP-AES, XRF, and ICP-MS are used to analyze and test the major, trace, and rare earth elements in the original rock and altered rock. The inert components are determined based on the isocon line. The Gresens equation is then used to quantitatively analyze the element migration during the evolution process, summarizing the migration and evolution characteristics of each element in each evolution type of the deposit;

[0013] Zircon Hf isotope study: Hf isotope determination of products formed by magmatic activity was performed using MC-ICPMS to trace the magma source area;

[0014] S4: Construction of mineralization model: Integrate the spatiotemporal relationship of multiple periods of magmatic activity, combine the migration patterns of major and trace elements in the whole rock and Hf isotope tracing data, establish a porphyry-skarn composite mineralization zoning model centered on the composite rock body, and determine deep prospecting targets.

[0015] Furthermore, the structural analysis in step S2 includes: measuring the kinematic parameters of the geological boundaries, fold structures and fault traces within the dissecting window, and analyzing the ore-controlling structure in combination with the distribution characteristics of the Red Bull syncline ore body.

[0016] Furthermore, the quantitative analysis of element migration in step S3 includes: recording the altered element content as C A , the element content before alteration is recorded as C O , taking Al2O3 as an inert element, calculate the content ratio of Al2O3 before and after alteration in each alteration mineralization process, record it as k, and finally calculate C A 、C O , k are substituted into the Grant equation to calculate the element migration amount ΔC i , the formula is

[0017] Furthermore, step S3 includes: comparing the petrographic differences of porphyry zircons and tracing the characteristics of the magma source region through the εHf(t) value and the two-stage model age.

[0018] Furthermore, the mineralization zoning model in step S4 is specifically as follows: taking the composite rock mass as the center, the spatial configuration relationship between the Mo-Cu-W core mineralization zone and the Pb-Zn-Ag peripheral mineralization zone is divided to establish a mineralization model.

[0019] Furthermore, the mineralization zoning model can be determined by element concentration thresholds or ratios:

[0020] Cu-Mo core mineralized zone: Cu≥0.5%, Mo≥0.03%, Cu / (Pb+Zn)≥10, Mo / Ag≥1.

[0021] Pb-Zn-Ag peripheral mineralization zone: Pb+Zn≥2%, Ag≥50ppm, Cu / (Pb+Zn)≤0.5, Mo / Ag≤0.1.

[0022] Furthermore, the fold axial surface attitude measurement in the structural analysis is recorded using a three-dimensional coordinate system of strike / dip / inclination, and the fold hinge line equation is established:

[0023]

[0024] Where θ is the dip angle, Δx, Δy, and Δz are the GPS coordinate differences, and the structural surface with θ>30° is determined to be the dominant ore-controlling occurrence.

[0025] Furthermore, the main mineralization period determination criteria include:

[0026] Define the migration rate thresholds of Cu and Mo elements:

[0027]

[0028] When η Cu ≥300% and η Mo When ≥150%, it is determined to be the main mineralization period.

[0029] Furthermore, the calculation of the migration rate η must meet the following requirements: the surrounding rock sampling spacing is ≤ 20m×20m grid; the ore samples are taken within 0.5-1.5 times the rock mass radius from the contact zone;

[0030] The test was performed using a PANalytical Axios MAX XRF spectrometer with detection limits of Cu = 5 ppm and Mo = 2 ppm.

[0031] Furthermore, the zoning model is constructed using the Kriging interpolation algorithm:

[0032]

[0033] Where h is the sample point spacing, and N is the number of sample points involved in the calculation;

[0034] Set the nugget value C of the variation function o ≤0.15, base value C+C o ≥0.85;

[0035] Create element band indices:

[0036]

[0037] When the element zoning index Z>1.2, it is classified as the Mo-Cu-W core band.

[0038] Beneficial effects of the present invention:

[0039] This paper, through a detailed analysis of multi-stage magmatic activity events in the region and mining area, systematically integrates field geological surveys, structural analysis, borehole cataloging, and indoor petrography, mineralogy, isotopes, and other multi-dimensional data to comprehensively clarify the spatial and temporal complex superposition relationship of porphyry and skarn mineralization systems. Taking the multi-stage intrusive complex rock body as the main control framework, the intrusive contact relationship and ore body distribution characteristics of porphyry bodies and skarn belts in different mineralization stages such as the Late Triassic and Late Cretaceous are precisely identified. Through the coordination of multiple technologies such as garnet U-Pb dating and zircon isotope tracing, the petrogenesis and mineralization ages of skarn and porphyry mineralization systems are accurately defined, and it is clear that multi-stage magmatic intrusions and their evolutionary processes are closely related to the enrichment of mineralization metal elements, thereby verifying that large-scale mineral deposits must have the essence of multi-stage superposition, crust-mantle material circulation, and composite dynamic driving. This not only enriches the theory of mineralization dynamics, but also provides a new paradigm for the genetic model of global multi-element composite mineralization systems.

[0040] The present invention systematically collects rock and ore samples from porphyry-skarn intrusive zones, alteration zones, and typical ore bodies. It comprehensively employs scanning electron microscopy (BSE) observations, in-situ LA-ICP-MS, and other mineral micro-area testing methods to meticulously analyze the mineral assemblage, intergrowth relationships, and alteration sequences of the porphyry-skarn contact zone and alteration zones, revealing the activation, migration, and enrichment mechanisms of ore-forming metal elements (such as Cu, Mo, and Zn) at different temporal and spatial stages. The migration trends of major and trace elements and the characteristics of sulfide zoning not only directly reflect the physicochemical changes and mineralization phases of hydrothermal fluids in contact metasomatic environments, but also trace the specific sources of ore-forming metals, providing a scientific basis for determining the contribution of mineralization at each stage and the enrichment locations of ore bodies. This method breaks through the traditional static ore body description model and achieves dynamic analysis from microscopic mineral-element to macroscopic ore deposit systems, significantly enhancing the depth of refined understanding of element sources and enrichment patterns.

[0041] The invention fully integrates the spatiotemporal configuration of different phases of magmatic activity and ore-controlling structures, establishing a spatial zoning model with a complex rock mass at the core, a skarn-porphyry mineralized alteration zone as the ring, and a polymetallic mineralized outer zone at the periphery. This zoning model, based on systematic and continuous geochemical element migration data, mineralogical and petrographic characteristics, and isotope tracing results, reveals the spatial sequence of ore-forming elements from the center to the periphery and the distribution patterns of metal elements at different mineralization stages. This achieves a comprehensive expansion of target area prediction from the surface to the deep, from exposed to concealed, and even to unexplored areas in the periphery, significantly breaking through the previous technical bottlenecks in prospecting for deep and concealed ore bodies and greatly improving the scientific nature and accuracy of prospecting.

[0042] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 This is a typical ore body profile of Hongniu-Hongshan;

[0045] Figure 2 Quartz diorite porphyry zircon 206 Pb / 238 U- 207 Pb / 235 U Age Concord Chart;

[0046] Figure 3 Quartz monzonite porphyry zircon 206 Pb / 238 U- 207 Pb / 235 U Age Concord Chart;

[0047] Figure 4 granite porphyry zircon 206 Pb / 238 U- 207 Pb / 235 U Age Concord Chart;

[0048] Figure 5 This is the LA-SF-ICP-MS dating result of skarn garnet;

[0049] Figure 6 This is the histogram of the lithogenesis and mineralization ages of the Hongniu-Hongshan copper-molybdenum deposit;

[0050] Figure 7 This is a typical drill hole histogram of the Red Bull mining area;

[0051] Figure 8 It is the migration trend diagram of major elements in each alteration (mineralization) contact process;

[0052] Figure 9 It is the migration trend diagram of trace elements in each alteration (mineralization) contact process;

[0053] Figure 10 It is the migration trend diagram of rare earth elements in each alteration (mineralization) contact process;

[0054] Figure 11 Zircon ε from the Hongniu-Hongshan copper-molybdenum deposit Hf (t)-T relationship diagram and two-stage Hf pattern age histogram

[0055] Figure 12This is the mineralization model diagram of the Hongniu-Hongshan copper-molybdenum deposit. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0057] Example 1

[0058] The present invention relates to a prospecting prediction method for a composite rock mass dissection porphyry-skarn composite mineralization system, which is implemented in the Hongniu-Hongshan Cu-Mo deposit in northwest Yunnan. The present invention is described in detail below with reference to the accompanying drawings:

[0059] The Hongniu-Hongshan copper deposit in northwestern Yunnan is located in Geza Township, Shangri-La City, with geographical coordinates of 99°51'57″~99°54'57″ east longitude and 28°06'00″~28°09'00″ north latitude. The mining area is located in the Geza Arc, the southern section of the Yidun Island Arc, on the western margin of the Yangtze Platform. The northern section of the Yidun Island Arc is the Zhangxingchangtai Arc, and the southern section of the Geza Arc is a compressional arc. It has experienced tectonic actions such as subduction orogenesis, collision orogenesis, post-orogenic extension and intracontinental convergent orogenesis, forming four important granite magma events. Among them, the arc granite magma event caused by the Indosinian subduction orogenesis and the A-type granite intrusion event caused by the post-orogenic extension of the late Yanshanian period are the two most important magmatic eruption periods, and are also the two major mineralization periods. Porphyry-skarn copper polymetallic deposits were formed in the Geza Island Arc.

[0060] The following evidence is used to establish a composite mineralization system, reveal the superimposed mineralization mechanism, and use the method of the present invention to reveal the superimposed mineralization of the complex porphyry body. Then, a mineralization model map is established to provide a theoretical basis and technical support for prospecting and exploration, specifically including:

[0061] The fold that is currently most closely related to mineralization in the mining area is the Hongniu syncline. Small ore bodies have been found locally in the Hongshan anticline, but the level of work is very low. Only surface geological measurements have been carried out on other fold structures, and no obvious ore bodies have been found. The Hongniu-Hongshan copper deposits are both produced in the Hongniu syncline. The east wing of the syncline is the output location of the EKT3 ore body group and the KT21 ore body group of the Hongshan mining section and the eastern mining belt of the Hongniu mining section, forming porphyry copper-molybdenum deposits and skarn-type iron-copper deposits. The core of the syncline is near the output location of the KTI and KT2 ore body groups of the Hongniu mining section, forming long-range skarn-type copper deposits. The west wing of the syncline is the output location of the KT3, KT4, and KT5 ore body groups of the Hongniu mining section, forming long-range skarn-type copper deposits, with sporadic lead-zinc ore bodies. The mineralization on both wings of the syncline is more favorable than that in the core, and the shallow part is more favorable than the deep part. The ore body extends farther along the dip than the strike and is larger in scale. The mineralization on the east wing is more favorable than that on the west wing. The ore body is larger in scale, more stable in shape, and thicker in thickness. It is the output location of the main ore body (such as Figure 1 ).

[0062] (1) In order to systematically determine the magmatic intrusion events in the Hongniu-Hongshan mining area, this study selected quartz diorite porphyry, quartz monzonite porphyry, granite porphyry and skarn for zircon and garnet U-Pb dating tests, and obtained the formation age of quartz diorite porphyry to be 247.4±1.9Ma, 42.99±0.35Ma, 40.67±0.40Ma (e.g. Figure 2 ), among which the 247.4±1.9Ma magmatic intrusion event is the product of the late Triassic tectonic-magmatic activity; but at the same time, two groups of ages of 42.99±0.35Ma and 40.67±0.40Ma are obtained, which belong to the late Oligocene, which provides new evidence for the existence of Himalayan tectonic-magmatic-mineralization in this area; the crystallization ages of the Hongniu quartz monzonite porphyry are 77.27±0.70Ma and 76.99±0.75Ma (such as Figure 3 ), the crystallization ages of the buried granite porphyry in the deep part of the Hongniu-Hongshan Cu-Mo deposit are 80.11±0.63Ma, 76.59±0.53Ma and 76.49±0.63Ma (e.g. Figure 4 ), are products of Late Cretaceous tectonic-magmatic activity; the U-Pb ages of skarn garnets are 84.2±3.0Ma and 81.7±3.5Ma (e.g. Figure 5 ), further limiting the mineralization age of the deposit to Late Cretaceous.

[0063] The analysis of the currently available isotope chronology data in the comprehensive area shows that the time limits of the magmatic activity and mineralization events of the Hongniu-Hongshan copper-molybdenum deposit are mainly concentrated in 199.0-247.4Ma, 73.4-84.2Ma, 40.7-43.0Ma (such as Figure 6These age evidences indicate that Hongniu and Hongshan belong to the same mineralization system, and that three phases of magmatic activity occurred in the mining area, namely the Late Triassic, Late Cretaceous and Late Oligocene, and that multiple phases of mineralization were superimposed and composited in the same deposit.

[0064] (2) During the core comprehensive cataloging, it was found that the Hongniu-Hongshan mining area has obvious vertical zoning characteristics. Generally speaking, the vertical zoning is characterized by alternating marble and skarn, with a small amount of hornfels in between. The three are closely related. The original rock of skarn mainly comes from marble (such as Figure 7 ). This study mainly focused on drilling holes along the typical exploration lines of the Red Bull Copper Mine, and collected a total of 30 rocks, including slate, marble, skarnized marble, skarnized hornfels, skarn, granite porphyry, and quartz monzonite porphyry. Rock geochemical testing and analysis were carried out, and the element migration characteristics were summarized through calculation results. It was found that the mining area can be divided into three alteration (mineralization) contact processes: ① marble → skarnized marble → skarn; ② slate → hornfels → skarnized hornfels → skarn; ③ porphyry → skarn → skarn ore. Since three types of alteration mineralization are involved, the rocks (ores) in each process are different, and each step of each alteration mineralization type is defined as the first process, the second process, and the third process. One type of sample in each process is regarded as a sample and the average value of each element is calculated, which is recorded as the element content C of the alteration. A and the element content C before alteration O , also taking Al2O3 as an inert element, calculate the content ratio of Al2O3 before and after alteration in each alteration mineralization process, record it as k, and finally C A 、C O , k are substituted into the Grant equation to calculate the element migration amount ΔC i , the formula is

[0065] Calculations of element migration revealed the migration characteristics of major elements during skarn mineralization in the Hongniu copper mine. TiO2 and P2O5 migrated weakly (<1.6%), while CaO and TFeO migrated significantly during the skarnization stage (slate / porphyry → skarn → ore). In particular, large influxes of CaO and SiO2 (>1000) occurred during the skarn-to-ore stage, suggesting that silicification and carbonatization were the dominant mineralization mechanisms. Silicification increases the brittleness of carbonate rocks, forming fissures that promote metasomatism with ore-bearing hydrothermal fluids. Simultaneously, the continuous influx of TFeO is associated with the formation of minerals such as garnet, reflecting an Fe-rich mineralization environment. The marble-to-skarn process exhibits CaO outflow and weak TFeO inflow, indicating differential dual metasomatism in the contact zone between hornfels and limestones. In the open system, LOI continuously migrates to form hydrous minerals and pore structures. The combined effect of temperature and pressure reduction promotes the precipitation of metal elements. SiO2, CaO, TFeO and ore-forming elements Cu and Mo reach their peak migration simultaneously in the skarn to ore stage, marking the main mineralization period. In summary, the element mobility (Ca, Fe, Si) of the skarnization process and the structural-physicochemical conditions synergistically control the location of ore bodies (such as Figure 8 ).

[0066] The ore-forming elements (Cu, Mo, W, Ag, Zn) in the Hongniu copper mine area all showed net migration during the alteration and mineralization process, among which Cu and Zn continuously migrated throughout the whole process, while Mo, W, and Ag occasionally migrated out in small amounts; the migration intensity was ranked by alteration type as porphyry → skarn → ore > slate → hornfels → skarn > marble → skarn, which was consistent with the migration trend of major elements. Cu and As, Ag, and Zn have the characteristics of coordinated migration (As can be used as an indicator element for prospecting), while Mo is closely related to the skarnization process and migrates strongly. The skarn → ore stage is the peak period of Cu, Mo, and Zn migration, and the Ag peak is seen in the porphyry → skarn stage (such as Figure 9 ); rare earth elements (La, Ce, etc.) are significantly enriched in the porphyry → skarn → ore stage, reflecting that the hydrothermal alteration intensity is the greatest in this stage (e.g. Figure 10 ).

[0067] (3) Zircon has strong stability. After formation, the Hf isotope composition is generally less affected by later geological events. Higher Hf content and lower 170 Lu / 177 The Hf ratio (usually less than 0.002) can obtain accurate information on the Hf isotope composition of zircon. Therefore, the study of Hf isotope composition is an important means to trace the source of host rocks and explore the interaction between magma formation, crustal evolution and crust-mantle interaction. 170 Lu / 177 The ratios of Hf are all less than 0.002, indicating that 176 The amount of radioactive Hf formed by Lu decay is very small, so it can be used 170 Lu-177 The value of Hf represents the time when zircon was formed. 179 Lu- 177 The value of Hf.

[0068] This study conducted a Hf isotope study on the products of the three phases of magmatic activity. The quartz diorite porphyry of the Indosinian period (247-198 Ma) is a product of island arc magmatic activity in the Late Triassic. 176 Yb / 177 The Hf ratio distribution range is 0.088006 to 0.037599, with an average value of 0.282711; 176 Lu / 177 The Hf ratio distribution range is 0.002396~0.001147, with an average value of 0.001676. Hf The (t) value ranges from -4.2 to 9.3, with an average value of 2.99, and the corresponding second-order mode age T DM2 The zircon ε of the Yanshanian samples (84-73 Ma) is 626-1379 Ma, with an average of 977.44 Ma. Hf (t) = -10.3 to -4.6, corresponding to the second-order mode age T DM2 The zircon in the rock samples of Himalayan period (43-40 Ma) is 1277-1582 Ma, with an average of 1376 Ma. 176 Yb / 177 The Hf ratio is 0.000676-0.001911, ε Hf (t) values ​​range from -1.4 to 0.7, with an average value of -0.5. The first-order mode age T DM1 The second-order model age T DM2 945~1056Ma, with an average of 1011Ma; Lu / Hf The values ​​range from -0.98 to -0.94, with an average of -0.96.

[0069] Further analysis of provenance evolution characteristics shows that the early (216-198 Ma) magmatic rocks are characterized by ε Hf (t)>0, and the middle period (81~76Ma) is dominated by ε Hf (t) < 0, and the late period (40-42 Ma) showed a range between the two (ε Hf (t)≈0) features (such as Figure 11 The evolution of Lu-Hf isotope composition shows that the ε Hf The (t) value shows a trend of changing from slightly higher in the Indosinian period to slightly lower in the late Yanshan period and then to slightly higher in the Himalayan period. DMC(Hf)) is mainly composed of mantle-derived components, with more juvenile crust and some Paleoproterozoic crust-derived materials. In the middle period, it is mainly derived from Mesoproterozoic crust, with a small amount of Paleoproterozoic crust-derived materials. In the late period, it is mainly derived from Mesoproterozoic crust, but there is contamination from enriched mantle.

[0070] Comprehensive studies have shown that the Hongniu-Hongshan copper-molybdenum deposit experienced three phases of magmatic activity: the Late Triassic (199.0-247.4 Ma), the Late Cretaceous (73.4-84.2 Ma), and the Late Oligocene (40.7-43 Ma). These multiple phases of mineralization are superimposed and complex within the same deposit. During the Late Triassic, a skarn-type Cu polymetallic mineralization system developed, associated with quartz diorite porphyry and monzobium porphyry. Late Cretaceous magmatic and hydrothermal activity, however, contributed significant amounts of Cu, Mo, and W, with the enrichment of these elements being more closely associated with the intrusion of the porphyry, forming a composite Cu-Mo-W-Pb-Zn-Ag polymetallic mineralization system. The Late Triassic magmatic intrusion likely originated from magma resulting from partial melting of Mesoproterozoic and Neoproterozoic continental crust and mixing with mantle-derived material. The Late Cretaceous ore-forming porphyry originated from anatexis of the Mesoproterozoic crustal basement, and the formation of the complex porphyry body is closely related to partial melting of the thickened crust of the Geza Island Arc during the Late Triassic. Northwest-trending longitudinal and northeast-trending faults provided pathways for the migration of ore-bearing hydrothermal fluids prior to mineralization. Joint and fracture systems, interstratified fracture zones, and lithologic structural surfaces formed during the mineralization period provided favorable ore-bearing reservoirs. The high-temperature, high-salinity NaCl-H₂O hydrothermal fluids of the Hongniu-Hongshan copper-molybdenum deposit were primarily derived from Late Triassic island-arc quartz diorite porphyry magmatism. The late ore-forming fluids are intermediate-temperature, high-salinity NaCl-CO₂-H₂O hydrothermal fluids, primarily derived from concealed Late Cretaceous orogenic extensional granitic magmatic intrusions. These two different sources of ore-forming fluids co-occurred in the same space. The deposit contains a variety of mineralizing elements, including Cu, Mo, W, Pb, Zn, Au, and Ag. The deposit exhibits distinct zoning centered on the rock mass. Mo (W) mineralization dominates the center (inside the rock mass), Cu, Mo, and W mineralization dominates the middle (skarn and hornfels), and Pb, Zn, Au, and Ag mineralization dominates the periphery.

[0071] The present invention establishes the mineralization model of the Hongniu-Hongshan copper-molybdenum deposit in northwest Yunnan based on the research results of regional geological background, regional tectonic evolution, geological characteristics of ore deposits, and rock-forming and mineralization material systems (such as Figure 12 ), which can effectively guide deep exploration and peripheral mineral exploration and has important geological significance.

[0072] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A prospecting prediction method based on the composite rock mass anatomy of porphyry-skarn composite mineralization system, characterized in that: The following steps are involved: S1: Data collection and collation: Systematically collect the results of mineral geological surveys in the study area, comprehensively analyze the regional tectonic evolution and metallogenic geological background, and sort out the spatial distribution characteristics, metallogenic conditions and ore-controlling factors of the Late Cretaceous ore-bearing porphyry bodies; S2: Field investigation and sampling: Based on preliminary geological and mineral research, representative blocks are selected as dissecting windows. The kinematic characteristics of the geological bodies are analyzed using structural analysis methods. The contact relationship of the porphyry intrusion is determined in combination with borehole logging. Rock and mineral samples are systematically collected from the porphyry-skarn contact zone, alteration zones, and vein intersections. S3: Indoor analysis test: Petrographic and mineralogical analysis: Identify mineral intergrowth relationships and alteration sequences through scanning electron microscope backscatter images, and divide mineralization stages; Garnet and zircon U-Pb dating: LA-ICP-MS is used to determine the diagenetic age of skarns and igneous rocks, systematically determining the period of magma intrusion in the mining area; Analysis of major and trace elements in rocks: ICP-AES, XRF, and ICP-MS are used to analyze and test the major, trace, and rare earth elements in the original rock and altered rock. The inert components are determined based on the isocon line. The Gresens equation is then used to quantitatively analyze the element migration during the evolution process, summarizing the migration and evolution characteristics of each element in each evolution type of the deposit; Zircon Hf isotope study: Hf isotope determination of products formed by magmatic activity was performed using MC-ICPMS to trace the magma source area; S4: Construction of mineralization model: Integrate the spatiotemporal relationship of multiple periods of magmatic activity, combine the migration patterns of major and trace elements in the whole rock and Hf isotope tracing data, establish a porphyry-skarn composite mineralization zoning model centered on the composite rock body, and determine deep prospecting targets.

2. The mineral prospecting prediction method according to claim 1, wherein: The structural analysis in step S2 includes: measuring the kinematic parameters of the geological boundaries, fold structures and fault traces within the dissecting window, and analyzing the ore-controlling structure in combination with the distribution characteristics of the Red Bull syncline ore body.

3. The mineral prospecting prediction method according to claim 1, wherein: The quantitative analysis of element migration in step S3 includes: recording the altered element content as C A , the element content before alteration is recorded as C O , taking Al2O3 as an inert element, calculate the content ratio of Al2O3 before and after alteration in each alteration mineralization process, record it as k, and finally calculate C A 、C O , k are substituted into the Grant equation to calculate the element migration amount ΔC i , the formula is 4. The prospecting prediction method according to claim 1, wherein: Step S3 includes: comparing the petrographic differences of porphyry zircons and tracing the characteristics of the magma source area through the εHf(t) value and the two-stage model age.

5. The mineral prospecting prediction method according to claim 1, wherein: The mineralization zoning model in step S4 is specifically as follows: taking the composite rock mass as the center, the spatial configuration relationship between the Mo-Cu-W core mineralization zone and the Pb-Zn-Ag peripheral mineralization zone is divided to establish a mineralization model.

6. The mineral prospecting prediction method according to claim 5, wherein: The mineralization zoning model can be determined by element concentration thresholds or ratios: Cu-Mo core mineralized zone: Cu≥0.5%, Mo≥0.03%, Cu / (Pb+Zn)≥10, Mo / Ag≥1. Pb-Zn-Ag peripheral mineralization zone: Pb+Zn≥2%, Ag≥50ppm, Cu / (Pb+Zn)≤0.5, Mo / Ag≤0.1.

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