A comprehensive method for judging fluid mineralization with participation of organic matter

Abstract

The application provides a comprehensive discrimination method for fluid mineralization of organic matter, and the method is characterized in that, for the samples collected from the same deposit, six types of analysis methods are integrated in a unified research framework, including microscopic observation and cathodoluminescence imaging, in-situ micro-area trace element and rare earth element analysis by laser ablation inductively coupled plasma mass spectrometry, in-situ sulfur isotope analysis by laser ablation multi-receiver inductively coupled plasma mass spectrometry, calcite fluid inclusion temperature measurement, microscopic laser Raman spectrum test and X-ray photoelectron spectroscopy (XPS) test, so that the mineral generation sequence is systematically determined, the ore-forming fluid evolution is revealed, and the organic matter participation in fluid mineralization is distinguished from three dimensions of ore minerals, gangue minerals and altered organic matter. The application realizes systematic and multi-dimensional evaluation of the organic matter mineralization contribution, overcomes the technical limitations of high uncertainty of single method discrimination, and comprehensively reveals the action mechanism of the organic matter in the fluid mineralization process.

Description

Technical Field

[0001] This invention relates to the field of mineralization technology, specifically to a comprehensive method for identifying the participation of organic matter in fluid mineralization. Background Technology

[0002] The spatial coexistence of organic matter and metallic mineral deposits is widely observed in various types of metallic mineral deposits worldwide, especially in lead-zinc deposits where the association with organic matter is most prominent. The Jinding lead-zinc deposit in the Lanping Basin of western Yunnan is a representative example of a super-large lead-zinc deposit, whose mineralization process is closely related to organic matter, making it a typical natural laboratory for studying the role of organic matter in fluid mineralization.

[0003] However, the current research on the participation of organic matter in fluid mineralization faces the following major technical problems: (1) The division of mineral formation stages is unclear: existing studies still have disputes on the order of formation of different forms (disseminated, colloidal, coarse-grained) sulfides and calcite minerals, and lack a systematic multi-method joint identification method; (2) The structural characteristics and sources of organic matter are not sufficiently analyzed: existing studies mostly focus on macroscopic organic geochemical parameters, and the microscopic chemical structure of functional groups of elements such as carbon, nitrogen, sulfur, and oxygen in organic matter is insufficient, which restricts the understanding of the mechanism of organic matter participation in mineralization; (3) The properties and evolution process of mineralizing fluids are unclear: the composition, temperature, redox properties and sources of fluids in different mineralization stages lack systematic in-situ analytical data support; (4) The criteria for distinguishing the modes of organic matter participation in fluid mineralization (bacterial sulfate reduction BSR, thermochemical sulfate reduction TSR and organic matter thermal desulfurization TDS) are insufficient, and the results obtained by existing analytical methods have great uncertainty, making it difficult to fully reveal the mechanism of organic matter in the fluid mineralization process. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a comprehensive method for identifying the participation of organic matter in fluid mineralization. This invention provides a method that can comprehensively reveal the role and mechanism of organic matter in the fluid mineralization process.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a comprehensive method for identifying the participation of organic matter in fluid mineralization, comprising the following steps: (1) Conduct field geological surveys at the target deposit, and collect core samples and outcrop samples as comparative samples for mineralized sections and the periphery of the ore body. The types of comparative samples include lead-zinc metal sulfide ores, calcite gangue and organic matter-containing sections; divide the mineralization stages into pre-mineralization, early-mineralization and late-mineralization stages; prepare rock thin sections, probe sections and fluid inclusion sections from the comparative samples; (2) Polarization microscopy was used to observe the ore minerals, gangue minerals and organic matter on the thin rock section. The luminescence characteristics of calcite were obtained by cathodic emission imaging on the thin rock section. The mineral formation sequence was determined based on the results of the polarization microscopy and the luminescence characteristics of calcite, and the different phases of pyrite, sphalerite, calcite and galena in the mining area were divided. The correspondence between the mineralization stages and mineral periods is as follows: Early mineralization stage: disseminated pyrite, denoted as Py1; cemented calcite, denoted as Cal1; Early mineralization stage: colloidal pyrite, designated Py2; disseminated sphalerite, designated Sp1; colloidal sphalerite, designated Sp2; coarse-grained calcite, designated Cal2; disseminated galena, designated Gn1; Late mineralization stage: coarse-grained euhedral pyrite, designated Py3; coarse-grained euhedral sphalerite, designated Sp3; coarse-grained calcite veins, designated Cal3; coarse-grained euhedral galena, designated Gn3; (3) On the probe sheet, laser ablation inductively coupled plasma mass spectrometry is used to perform in-situ micro-area trace element and rare earth element content analysis on pyrite, sphalerite and calcite of different periods divided in step (2). The mineral genesis is determined by the S / Se content ratio of pyrite and sphalerite, the mineralization temperature evolution is determined by the Zn / Cd content ratio of sphalerite, the fluid redox properties are determined by the Fe-Mn-Mg triangular component projection of calcite, and the fluid source is traced by the rare earth element distribution pattern and Y / Ho content value of calcite. (4) On the probe sheet, in-situ sulfur isotope δ¹⁴ spectroscopy was performed on the pyrite and sphalerite from different phases divided in step (2) using laser ablation multi-receiver inductively coupled plasma mass spectrometry. 34 S-analysis, through δ 34 The variation trend of S in different mineralization stages is used to identify the sulfur source reaction mechanism, which includes one or more of bacterial sulfate reduction, thermochemical sulfate reduction and organic matter thermal desulfurization. (5) On the fluid inclusion sheet, the homogenization temperature of the fluid inclusions in Cal2 and Cal3 divided in step (2) is measured to obtain the homogenization temperature range of the ore-forming fluids of Cal2 and Cal3 respectively. (6) Microscopic laser Raman spectroscopy is performed on the thin rock section to obtain the highest paleotemperature experienced by the asphalt; the highest paleotemperature is compared with the homogenization temperature range of the ore-forming fluid in step (5). If the highest paleotemperature is within the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid is contemporaneous with the early ore-forming fluid. If the highest paleotemperature is higher than the upper limit of the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid experienced an earlier high-temperature thermal event. The homogenization temperature range of the ore-forming fluid in Cal3 is used to judge the cooling evolution trend of the ore-forming fluid. When the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal3, it is determined that the ore-forming fluid has evolved from early high temperature to late low temperature cooling. Organic powder was extracted from the comparative sample; X-ray photoelectron spectroscopy was performed on the organic powder to obtain the aromatic carbon ratio, S / C atomic ratio and pyrrole nitrogen / pyridine nitrogen ratio of the organic matter, and to determine whether the organic matter alteration mechanism was caused by thermochemical sulfate reduction or thermal alteration. (7) Based on the results obtained in steps (1) to (6), establish a systematic analysis of the mineral formation sequence, ore-forming fluid evolution and organic matter participation mode, and obtain the organic matter participation fluid mineralization mode; There is no temporal order between steps (3) and (5); the micro-laser Raman spectroscopy test, X-ray photoelectron spectroscopy test in step (6), and steps (3) and (5) are not in temporal order.

[0006] Preferably, in step (2), the polarization microscope observation includes observation with transmitted single-polarized light, orthogonal polarized light, and reflected light; The results observed by the polarization microscope include mineral morphology, organic matter occurrence characteristics, and the interpenetration relationship between various minerals; the mineral morphology includes one or more of the following: disseminated, colloidal, and coarse-grained; the organic matter occurrence characteristics include optical structure, which includes one or more of the following: mosaic and homogeneous.

[0007] Preferably, in step (2), the accelerating voltage of the cathode luminescence imaging is 5~10kV and the beam current is 0.5mA; The luminescent characteristics of the calcite include luminescence color and zoning features. Cal1 cathodoluminescence is bright yellow with uniform internal zoning and is replaced by Py1. Cal2 cathodoluminescence is dark orange to dark yellow with visible weak oscillating zoning. Py2, Sp2 and Cal2 coexist, indicating that Cal2, Py2 and Sp2 were formed at the same time. Cal3 cathodoluminescence is dark red with significant oscillating zoning. Cal3 coexists with Sp3, Gn3 and Py3.

[0008] Preferably, in step (3), the test conditions for laser ablation inductively coupled plasma mass spectrometry include: the laser ablation carrier gas is He, the compensation gas is Ar; the laser frequency is 8~10Hz, and the energy is 6~10J / cm. 2 The beam spot diameter is 44μm, and the signal is acquired for 100s at each point; The method for determining the mineral origin by the S / Se content ratio of pyrite and sphalerite includes: if the S / Se content ratio is <15000, the mineral is formed by magmatic sulfides; if the S / Se content ratio is 10000~28000, the mineral is formed by hydrothermal sulfides. The method for determining the evolution of mineralization temperature by the Zn / Cd content ratio of sphalerite includes: a higher Zn / Cd content ratio indicates a higher mineralization temperature; the Zn / Cd content ratio of Sp1 is 186, and the Zn / Cd content ratio of colloidal sphalerite Sp2 is 158, indicating a medium-high temperature environment; the Zn / Cd content ratio of Sp3 is 97, reflecting a systematic decrease in mineralization temperature; The method for determining the redox properties of a fluid by projecting the Fe-Mn-Mg triangular composition of calcite is as follows: the movement of data points toward the Fe-Mn endmembers indicates an increase in the oxidizing power of the fluid. The method for tracing the fluid source through the Y / Ho content ratio of calcite includes: a Y / Ho content ratio of 44 to 74 indicates that the fluid source is marine sediments; a Y / Ho content ratio of 26 to 28 indicates that the fluid source is terrigenous clastic material or volcanic ash; and when the Y / Ho content ratio is greater than 28 and less than 44, it indicates that the fluid source is a mixture of marine sediments and terrigenous clastic material or volcanic ash. The method of tracing the source of fluids also includes: determining the source of fluids by comparing the in-situ trace element content of Py1 and Py2. When the content of Mo, Mn, Zn and As in Py2 is higher than that in Py1, it is determined that the deep heat source fluids participated in the mineralization.

[0009] Preferably, in step (4), the test conditions for the laser ablation multi-receiver inductively coupled plasma mass spectrometry include: using He as the carrier gas, Ar as the compensation gas, a laser frequency of 5 Hz, and an energy of 4 J / cm². 2 The beam spot diameter is 50 μm; The via δ 34 The specific steps for determining the sulfur source reaction mechanism by analyzing the changing trends of S at different mineralization stages include: when the δ of Py1 and Sp1 changes... 34 When the S values ​​are all < -10‰, the main sulfur source reaction mechanism is determined to be bacterial sulfate reduction; when the δ values ​​of Py3 and Sp3 are both < -10‰, the sulfur source reaction mechanism is determined to be bacterial sulfate reduction. 34 When the S value is 0 to +20‰ and the fluid inclusion temperature is >100℃, the sulfur source reaction mechanism is determined to be mainly thermochemical sulfate reduction; when δ34 When an independent peak appears in the frequency histogram distribution of the S value within the range of -5 to 0‰, and the corresponding sulfide is spatially associated with an organic-rich layer, the sulfur source reaction mechanism is determined to be thermal desulfurization of organic matter.

[0010] Preferably, in step (5), the conditions for measuring the homogeneity temperature of the fluid inclusion include: a temperature range of -160 to 350°C, an ambient temperature of 20 to 25°C, and a relative humidity of 30 to 50%. The homogenization temperature range of the ore-forming fluid of Cal2 is 146.3~283.2℃, and the homogenization temperature range of the ore-forming fluid of Cal3 is 66.0~185.7℃. When the peak temperature of the homogenized temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenized temperature range of the ore-forming fluid in Cal3, the ore-forming fluid evolves from early high temperature to late low temperature cooling.

[0011] Preferably, in step (6), the conditions for the microscopic laser Raman spectroscopy test include: a laser wavelength of 632.8 nm, an exposure time of 5–20 s, and a spectral range of 100–3000 cm⁻¹. -1 The spectral resolution is 0.6 cm⁻¹. -1 The spatial resolution was 400 nm, the ambient temperature was 22.3℃, and the humidity was 35%. The formula for calculating the highest paleotemperature is shown in Equation 1: T=737.3+320.9×R1-1067×R2-80.638×R1 2 Equation 1; Where R1 is the peak intensity ratio of peak D to peak G, and R2 is the peak area ratio of peak D to peak G; The asphalt includes intergranular asphalt filled with primary minerals, asphalt veinlets containing sulfides, and intergranular asphalt filled with hydrothermal vein minerals.

[0012] Preferably, in step (6), the conditions for the X-ray photoelectron spectroscopy test include: the excitation source is an Al Kα target, the excitation energy is 1486.6 eV, and the vacuum degree is < 5 × 10⁻⁶. -8 mbar; full spectrum scanning pass energy 100 eV, step size 1 eV; fine spectrum scanning pass energy 30 eV, step size 0.05 eV; spectral acquisition range 0~1350 eV, X-ray beam spot diameter 400 μm; C1s binding energy 284.8 eV as internal standard correction; The method for determining whether the organic matter alteration mechanism is caused by thermochemical sulfate reduction or thermal alteration includes: if the aromatic carbon atom ratio of asphalt is ≥75%, the S / C atomic ratio is 0.035~0.17, and the pyrrole nitrogen / pyridine nitrogen ratio is ≥3, then the organic matter alteration mechanism is caused by thermochemical sulfate reduction; if the aromatic carbon atom ratio of asphalt is <75%, the S / C atomic ratio is <0.035, and the pyrrole nitrogen / pyridine nitrogen ratio is <3, then the organic matter alteration mechanism is caused by thermal alteration.

[0013] Preferably, in step (7), the organic matter's participation in the fluid mineralization process includes three stages: Early mineralization stage: The ore-forming fluids are injected to form ancient oil reservoirs, and after bacterial sulfate reduction, they form H2S-rich fluids, which precipitate to form Py1 and Cal1; the ore-forming fluids are low-temperature reducing hydrocarbon-rich fluids; Early mineralization stage: The mineralization fluid extracts metallic substances, and the warming of the ancient oil reservoir changes the mineralization mode of organic matter to thermochemical sulfate reduction and thermal desulfurization of organic matter, accompanied by Cal2 precipitation and the formation of Py2, Sp1, Sp2 and Gn1; the mineralization fluid is a high-temperature reducing basin brine fluid. Late mineralization stage: The mineralization fluid is formed by the infiltration and leaching of low-temperature oxidizing atmospheric precipitation. Oxidizing atmospheric precipitation infiltration and leaching, destruction of ancient oil reservoirs, and the consumption of residual thermochemical sulfate reduction or thermal desulfurization of organic matter to form H2S.

[0014] Preferably, in the pre-mineralization stage, the temperature of the low-temperature reducing hydrocarbon-rich fluid is 77.56~148.22℃; In the early stage of mineralization, the temperature of the high-temperature reducing basin brine fluid is 146.3~283.2℃; The late-stage mineralization phase: the temperature of the mineralizing fluid formed by the infiltration and leaching of low-temperature oxidizing atmospheric precipitation is 66.0~185.7℃.

[0015] This invention provides a comprehensive method for identifying the participation of organic matter in fluid mineralization. For samples collected from the same deposit, it comprehensively utilizes six analytical techniques: microscopic observation and cathodoluminescence imaging, in-situ micro-area trace and rare earth element analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), in-situ sulfur isotope analysis using laser ablation multi-receiver inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), calcite fluid inclusion thermometry, micro-laser Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). From the three dimensions of ore minerals, gangue minerals, and altered organic matter, this method systematically clarifies the mineral formation sequence, reveals the evolution of ore-forming fluids, and identifies the modes of organic matter participation in fluid mineralization. This invention employs the above six analytical methods to study the participation of organic matter in fluid mineralization, achieving a systematic and multi-dimensional evaluation of the mechanism of organic matter's role in fluid mineralization. It overcomes the technical limitations of high uncertainty in single-method identification and comprehensively reveals the role mechanism of organic matter in the fluid mineralization process. Attached Figure Description

[0016] Figure 1 This is a technical roadmap of the present invention; Figure 2 The diagram shows the microscopic characteristics of metal sulfides under reflected light. In the diagram, a represents disseminated pyrite (Py1), b represents disseminated sphalerite (Sp1) and disseminated galena (Gn1), c represents colloidal pyrite (Py2) and colloidal sphalerite (Sp2), which are often distributed in concentric ring structures, d represents colloidal pyrite (Py2) growing around pyrite (Pre-Py), and e represents disseminated pyrite and sphalerite in the early stage of the Gn3+Cal3 vein cross section. Figure 3 The images show the cathodoluminescence characteristics of calcite, where a is the cathodoluminescence characteristic of Cal1, b is the cathodoluminescence characteristic of Cal3, c and d are comparison images of the cathodoluminescence characteristics of Cal2 and Cal1, and e and f are the cathodoluminescence characteristic images of Sp3 with a high degree of euhedrality. Figure 4 A graph showing the Zn / Cd ratio variation trend of sphalerite in different periods; Figure 5 A triangular diagram showing the atomic numbers of Mn, Mg, and Fe in calcite from the mining period; Figure 6 Box plots of trace elements (Pb, Ag, Mo, Tl) for disseminated pyrite (Py1) and colloidal pyrite (Py2); Figure 7 Box plots of trace elements (Mn, Ti, Zn, Ag) for disseminated pyrite (Py1) and colloidal pyrite (Py2); Figure 8 A graph showing the Ga / In and Ge / In content ratios of sphalerite in the Beichang mining area of ​​the Jinding deposit; Figure 9 Histogram of sulfur isotopic composition of metal sulfides in the Jinding deposit; Figure 10 This is a uniform temperature histogram of calcite inclusions from early mineralization (Cal2) to late mineralization (Cal3); Figure 11 This is a paleotemperature distribution map of bitumen ore in the Jinding mining area based on Raman spectroscopy. Figure 12 XPS fitting spectra of organic carbon (C1s) in the mining area are shown below. Among them, (a) is the XPS fitting spectra of organic carbon (1s) in sample 20JD95, (b) is the XPS fitting spectra of organic carbon (1s) in sample 20JD133, (c) is the XPS fitting spectra of organic carbon (1s) in sample 20JD129(1), and (d) is the XPS fitting spectra of organic carbon (1s) in sample 20JD129(2). Figure 13 The following are XPS fitting spectra of organic nitrogen (N1s) in the mining area: (a) is the XPS fitting spectra of organic nitrogen (1s) in sample 20JD95, (b) is the XPS fitting spectra of organic nitrogen (1s) in sample 20JD133, (c) is the XPS fitting spectra of organic nitrogen (1s) in sample 20JD129(1), and (d) is the XPS fitting spectra of organic nitrogen (1s) in sample 20JD129(2). Figure 14 XPS fitting spectra of organic sulfur (S2p) in the mining area are shown below. Among them, (a) is the XPS fitting spectra of organic sulfur (2p) in sample 20JD95, (b) is the XPS fitting spectra of organic sulfur (2p) in sample 20JD133, (c) is the XPS fitting spectra of organic sulfur (2p) in sample 20JD129(1), and (d) is the XPS fitting spectra of organic sulfur (2p) in sample 20JD129(2). Figure 15 XPS fitting spectrum of organic matter oxygen (O1s) in the mining area; Figure 16 The figures are scatter plots of the proportion of aromatic carbon atoms and nitrogen elements in the organic matter of the mining area. (a) is a graph showing the relationship between the proportion of aromatic carbon atoms and the number of nitrogen atoms, and (b) is a graph showing the relationship between the proportion of aromatic carbon atoms and pyrrole nitrogen / pyridine nitrogen. Detailed Implementation

[0017] This invention provides a comprehensive method for identifying the participation of organic matter in fluid mineralization, comprising the following steps: (1) Conduct field geological surveys at the target deposit, and collect core samples and outcrop samples as comparative samples for mineralized sections and the periphery of the ore body. The types of comparative samples include lead-zinc metal sulfide ores, calcite gangue and organic matter-containing sections; divide the mineralization stages into pre-mineralization, early-mineralization and late-mineralization stages; prepare rock thin sections, probe sections and fluid inclusion sections from the typical samples; (2) Polarization microscopy was used to observe the ore minerals, gangue minerals and organic matter on the thin rock section. The luminescence characteristics of calcite were obtained by cathodic emission imaging on the thin rock section. The mineral formation sequence was determined based on the results of the polarization microscopy and the luminescence characteristics of calcite, and the different phases of pyrite, sphalerite, calcite and galena in the mining area were divided. The correspondence between the mineralization stages and mineral periods is as follows: Early mineralization stage: disseminated pyrite, denoted as Py1; cemented calcite, denoted as Cal1; Early mineralization stage: colloidal pyrite, designated Py2; disseminated sphalerite, designated Sp1; colloidal sphalerite, designated Sp2; coarse-grained calcite, designated Cal2; disseminated galena, designated Gn1; Late mineralization stage: coarse-grained euhedral pyrite, designated Py3; coarse-grained euhedral sphalerite, designated Sp3; coarse-grained calcite veins, designated Cal3; coarse-grained euhedral galena, designated Gn3; (3) On the probe sheet, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used to perform in-situ micro-area trace element and rare earth element content analysis on pyrite, sphalerite and calcite of different periods divided in step (2). The mineral genesis is determined by the S / Se content ratio of pyrite and sphalerite, the mineralization temperature evolution is determined by the Zn / Cd content ratio of sphalerite, the fluid redox properties are determined by the Fe-Mn-Mg triangular component projection of calcite, and the fluid source is traced by the rare earth element distribution pattern and Y / Ho content value of calcite. (4) On the probe sheet, laser ablation multi-receiver inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) was used to perform in-situ sulfur isotope δ¹⁻¹ analysis on the pyrite and sphalerite from different phases divided in step (2). 34 S-analysis, through δ 34 The variation trend of S in different mineralization stages is used to identify the sulfur source reaction mechanism, which includes one or more of bacterial sulfate reduction (BSR), thermochemical sulfate reduction (TSR), and thermal desulfurization of organic matter (TDS). (5) On the fluid inclusion sheet, the homogenization temperature of the fluid inclusions in Cal2 and Cal3 divided in step (2) is measured to obtain the homogenization temperature range of the ore-forming fluids of Cal2 and Cal3 respectively. (6) Microscopic laser Raman spectroscopy is performed on the rock thin sections and fluid inclusion sections to obtain the highest paleotemperature experienced by the asphalt; the highest paleotemperature is compared with the homogenization temperature range of the ore-forming fluid in step (5). If the highest paleotemperature is within the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid is contemporaneous with the early ore-forming fluid. If the highest paleotemperature is higher than the upper limit of the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid experienced an earlier high-temperature thermal event. The homogenization temperature range of the ore-forming fluid in Cal3 is used to judge the cooling evolution trend of the ore-forming fluid. When the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal3, it is determined that the ore-forming fluid has evolved from early high temperature to late low temperature cooling. Organic powder was extracted from the comparative sample; X-ray photoelectron spectroscopy was performed on the organic powder to obtain the aromatic carbon ratio, S / C atomic ratio and pyrrole nitrogen / pyridine nitrogen ratio of the organic matter, and to determine whether the organic matter alteration mechanism was caused by thermochemical sulfate reduction (TSR) or thermal alteration (TCA). (7) Based on the results obtained in steps (1) to (6), establish a systematic analysis of the mineral formation sequence, ore-forming fluid evolution and organic matter participation mode, and obtain the organic matter participation fluid mineralization mode; There is no temporal order between steps (3) and (5); the micro-laser Raman spectroscopy test, X-ray photoelectron spectroscopy test in step (6), and steps (3) and (5) are not in temporal order.

[0018] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0019] This invention involves conducting field geological surveys of the target deposit, collecting borehole core samples and outcrop samples as comparative samples for mineralized sections and the periphery of the ore body, respectively. The types of comparative samples include lead-zinc metal sulfide ores, calcite gangue, and organic matter-containing sections; the mineralization stages are divided into pre-mineralization, early-mineralization, and late-mineralization stages; and rock thin sections, probe sections, and fluid inclusion sections are prepared from the typical samples.

[0020] In this invention, the field geological survey of the target deposit can be conducted by observing the geological profile of the target deposit to obtain the mineral morphology, occurrence, and interpenetration relationships, and to record the type of organic matter occurrence and its spatial relationship with the mineralized strata. In this invention, the mineral morphology can include one or more of disseminated, colloidal, and coarse-grained forms. In this invention, the organic matter can include one or more of solid bitumen, heavy oil, and kerogen. The purpose of the field geological profile observation of the target deposit in this invention is to determine the sampling location and sample type. In this invention, the organic matter is mainly found in the Upper Triassic source rocks (T3s, T3m) and the Lower Cretaceous-Paleocene ore deposits (K1j, E1y), exhibiting various occurrences such as disseminated, massive, fracture-filled, veinlet, and vug-filled forms, and is spatially closely associated with lead-zinc sulfide ore bodies. In this invention, the purpose of the field geological profile observation is to provide macro-geological basis for dividing mineralization stages and screening typical samples, and to lay the foundation for subsequent determination of mineral formation sequence and construction of organic matter participation in mineralization model.

[0021] This invention enables detailed classification, description, and recording of interrelationships of the collected drill core samples. It also allows for lithological description of the drill samples and outcrop samples. In this invention, the lithological description may include breccia and / or sandstone, where the sandstone is the core host rock of the lead-zinc sulfide ore body; the breccia consists of sandstone and limestone fragments, with calcite and lead-zinc sulfides filling the gaps between the breccia.

[0022] This invention does not impose any particular limitation on the preparation method of the rock thin section, probe sheet, and fluid inclusion sheet; any preparation method well known to those skilled in the art can be used. In this invention, the thickness of the rock thin section can specifically be 0.03 mm. In this invention, the thickness of the probe sheet can be 0.035~0.05 mm. In this invention, the thickness of the fluid inclusion sheet can specifically be 0.1 mm.

[0023] After obtaining the rock thin section, the present invention observes the ore minerals, gangue minerals and organic matter on the rock thin section using a polarization microscope, and uses cathodoluminescence imaging to obtain the luminescence characteristics of calcite on the rock thin section. Based on the results of the polarization microscope observation and the luminescence characteristics of calcite, the mineral formation sequence is determined, and different phases of pyrite, sphalerite, calcite and galena in the mining area are divided. The correspondence between the mineralization stages and mineral periods is as follows: Early mineralization stage: disseminated pyrite, denoted as Py1; cemented calcite, denoted as Cal1; Early mineralization stage: colloidal pyrite, designated Py2; disseminated sphalerite, designated Sp1; colloidal sphalerite, designated Sp2; coarse-grained calcite, designated Cal2; disseminated galena, designated Gn1; Late mineralization stage: coarse-grained euhedral pyrite, designated Py3; coarse-grained euhedral sphalerite, designated Sp3; coarse-grained calcite veins, designated Cal3; coarse-grained euhedral galena, designated Gn3; In this invention, the polarization microscopy observation can include observation with transmitted single-polarized light, orthogonally polarized light, and reflected light. For samples with a large field of view (i.e., a field of view larger than the single imaging range of the microscope), a full-scanning microscope of the rock thin sections can be used with an SD-3000A and the images stitched together using Power Mosaic software. In this invention, the polarization microscope can be a Leica DMLP polarization microscope.

[0024] In this invention, the ore minerals may include pyrite, sphalerite, and galena. In this invention, the organic matter may include solid bitumen.

[0025] In this invention, the results observed by the polarization microscope may include mineral morphology, optical structure of organic matter, and the interpenetration relationship between various minerals; the mineral morphology includes one or more of the following: disseminated, colloidal, and coarse-grained; the organic matter occurrence characteristics include optical structure, which includes one or more of the following: mosaic and homogeneous.

[0026] In this invention, the conditions for cathodoluminescence imaging may include: an accelerating voltage of 5-10 kV, specifically 5 kV, 6 kV, 7 kV, 8 kV, 9 kV, or 10 kV; a beam current of 0.5 mA; and a vacuum level of 80-120 mTorr, specifically 80 mTorr, 90 mTorr, 100 mTorr, 110 mTorr, or 120 mTorr. In this invention, the instrument used for cathodoluminescence imaging may be a CL8200 MK5-2 cathodoluminescence analyzer.

[0027] In this invention, the luminescent characteristics of the calcite include luminescent color and zoning characteristics. Cal1 cathodoluminescence is bright yellow with uniform internal zoning and is replaced by Py1. Cal2 cathodoluminescence is dark orange to dark yellow with visible weak oscillating zoning. Py2, Sp2 and Cal2 coexist, indicating that Cal2, Py2 and Sp2 were formed simultaneously. Cal3 cathodoluminescence is dark red with significant oscillating zoning. Cal3 coexists with Sp3, Gn3 and Py3.

[0028] This invention, through observation of mineral morphology using polarization microscopy and cathodoluminescence imaging, redefines the mineral formation sequence at different mineralization stages (pre-mineralization, early-mineralization, and late-mineralization), providing a basis for the division of subsequent steps. In this invention, the mineral formation sequence can include: Pre-mineralization: based on the formation of Py1 and Cal1; if microscopic observation shows Py1 replacing Cal1, it indicates that Py1 was formed later than Cal; Early-mineralization: based on the formation of Gn1 (disseminated galena), Sp1, Py2, and Sp2, accompanied by Cal2; colloidal mineralization occurs in concentric rings, exhibiting a sequence from the fracture wall to the center: pyrite-sphalerite-coarse-grained calcite; Late-mineralization: based on the formation of Cal3 and its associated Sp3 and Gn3. It can be seen that the early-stage minerals of the Gn3+Cal3 vein are cross-sectioned, and the calcite in the three stages are significantly different in cathodoluminescence images (Cal1 is bright yellow and homogeneous, Cal2 is darker and occasionally shows rings, and Cal3 is dark red and has significant oscillating rings).

[0029] This invention employs laser ablation inductively coupled plasma mass spectrometry (ICP-MS) to perform in-situ micro-area trace element and rare earth element analysis on pyrite, sphalerite, and calcite from different mineral phases. The S / Se value is used to determine the mineral genesis, the Zn / Cd ratio of sphalerite is used to determine the mineralization temperature evolution, the Fe and Mo contents of calcite and the Fe-Mn-Mg triangular component projection are used to determine the redox properties of the fluid, and the rare earth element distribution pattern and Y / Ho value of calcite are used to trace the fluid origin.

[0030] After obtaining the probe sheet, the present invention uses laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to perform in-situ micro-area trace element and rare earth element content analysis on the probe sheet for different phases of pyrite, sphalerite and calcite divided in step (2). The mineral genesis is determined by the S / Se content ratio of pyrite and sphalerite, the mineralization temperature evolution is determined by the Zn / Cd content ratio of sphalerite, the fluid redox properties are determined by the Fe-Mn-Mg triangular component projection of calcite, and the fluid source is traced by the rare earth element distribution pattern and Y / Ho content value of calcite.

[0031] In this invention, the LA-ICP-MS test conditions may include: the laser ablation carrier gas is He; the compensation gas is Ar; the laser frequency is 8~10Hz, or 9Hz; and the energy is 6~10J / cm. 2 Specifically, it can be expressed as 7J / cm 2 8J / cm 2 or 9J / cm 2 The beam spot diameter was 44 μm; each point was sampled for 100 seconds, with the background sample collected for the first 20 seconds and the sample signal collected for 50 seconds; the elemental content was calculated using the multi-external standard and total normalization method.

[0032] In this invention, the method for determining the mineral origin by the S / Se content ratio of pyrite and sphalerite may include: if the S / Se content ratio is <15000, the mineral is of magmatic sulfide origin; if the S / Se content ratio is 10000~28000, the mineral is of hydrothermal sulfide origin.

[0033] In this invention, the method for determining the evolution of mineralization temperature by the Zn / Cd content ratio of sphalerite may include: a higher Zn / Cd content ratio indicates a higher mineralization temperature; the Zn / Cd content ratio of Sp1 is 186, and the Zn / Cd content ratio of Sp2 is 158, indicating a medium-high temperature environment; the Zn / Cd content ratio of Sp3 is 97, reflecting a systematic decrease in mineralization temperature.

[0034] In this invention, the method for determining the redox properties of a fluid by projecting the Fe-Mn-Mg triangular composition of calcite may include: moving the data point toward the Fe-Mn endmember to indicate an increase in the fluid's oxidizing power.

[0035] In this invention, the method of tracing the fluid source by the Y / Ho content ratio of calcite may include: if the Y / Ho content ratio is 44 to 74, the fluid source is marine sediments; if the Y / Ho content ratio is 26 to 28, the fluid source is terrigenous clastic material or volcanic ash; and if the Y / Ho content ratio is greater than 28 and less than 44, it indicates that the fluid source is a mixture of marine sediments and terrigenous clastic material or volcanic ash. In this invention, the method of tracing the source of the fluid may further include: determining the source of the fluid by comparing the in-situ trace element content of Py1 and Py2; when the content of Mo, Mn, Zn and As in Py2 is higher than that in Py1, it is determined that the deep heat source fluid participated in the mineralization.

[0036] After obtaining the probe sheet, the present invention uses laser ablation multi-receiver inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to perform in-situ sulfur isotope δ¹⁻¹ analysis on the probe sheet for different phases of pyrite and sphalerite divided in step (2). 34 S-analysis, through δ 34 The variation trend of S in different mineralization stages is used to identify the sulfur source reaction mechanism, which includes one or more of bacterial sulfate reduction (BSR), thermochemical sulfate reduction (TSR), and thermal desulfurization of organic matter (TDS).

[0037] In this invention, the test conditions for LA-MC-ICP-MS may include: using He as the carrier gas, Ar as the compensation gas, a laser frequency of 5 Hz, and an energy of 4 J / cm². 2 The beam diameter was 50 μm; sulfur isotope mass fractionation was corrected using the SSB method and quantified using the external standard method.

[0038] In this invention, the method via δ 34 The specific steps for determining the sulfur source reaction mechanism by analyzing the changing trends of S at different mineralization stages include: when the δ of Py1 and Sp1 changes... 34 When the S values ​​are all < -10‰, the main sulfur source reaction mechanism is determined to be bacterial sulfate reduction; when the δ values ​​of Py3 and Sp3 are both < -10‰, the sulfur source reaction mechanism is determined to be bacterial sulfate reduction. 34 When the S value is 0 to +20‰ and the fluid inclusion temperature is >100℃, the sulfur source reaction mechanism is determined to be mainly thermochemical sulfate reduction; when δ 34 When an independent peak appears in the frequency histogram distribution of the S value within the range of -5 to 0‰, and the corresponding sulfide is spatially associated with an organic-rich layer, the sulfur source reaction mechanism is determined to be thermal desulfurization of organic matter.

[0039] This invention employs LA-MC-ICP-MS in-situ micro-region δ¹⁸O 34 The S analysis method obtains sulfur isotope composition point by point according to the phase (Py1 / Py2 / Py3, Sp1 / Sp2 / Sp3), which avoids phase contamination caused by the traditional whole rock powder method from the mechanism.

[0040] After obtaining the fluid inclusion sheet, the present invention performs fluid inclusion homogenization temperature measurement on Cal2 and Cal3 divided in step (2) on the fluid inclusion sheet to obtain the ore-forming fluid homogenization temperature range of Cal2 and Cal3 respectively.

[0041] In this invention, the conditions for determining the homogenization temperature of the fluid inclusions include: a temperature range of -160 to 350°C, an ambient temperature of 20 to 25°C, and a relative humidity of 30 to 50%, using a hot and cold stage for testing; the temperature measurement procedure includes: first, cooling to -160°C in stages, then heating to the point where the inclusions are completely homogenized, cooling down until bubbles reappear, and then heating up again to homogenization; if the difference between the two homogenization temperatures is >1°C, the temperature is measured again; if the difference is <1°C, the average value is taken. Because the volume of fluid inclusions in the experimental samples is generally small (<10 μm), the freezing point temperature error is relatively large and is not used as the primary data.

[0042] In this invention, the homogenization temperature range of the ore-forming fluid of Cal2 is 146.3~283.2℃, and the homogenization temperature range of the ore-forming fluid of Cal3 is 66.0~185.7℃.

[0043] In this invention, the rare earth element (REE) distribution patterns of Cal2 and Cal3 differ. Cal2 exhibits a higher rightward slant, while Cal3, although generally showing LREE enrichment, shows a relatively lower enrichment level, even exhibiting MREE enrichment and relative depletion of LREE and HREE. Since the above studies show that Cal2 was formed at a higher temperature than Cal3, these REE distribution patterns indicate that Cal2 and Cal3 were formed by ore-forming fluids of different properties.

[0044] In this invention, when the peak temperature of the homogenized temperature range of the ore-forming fluid of Cal2 is higher than the peak temperature of the homogenized temperature range of the ore-forming fluid of Cal3, the ore-forming fluid evolves from early high temperature to late low temperature cooling.

[0045] After obtaining the rock thin section, the present invention performs microscopic laser Raman spectroscopy on the rock thin section to obtain the highest paleotemperature experienced by the asphalt; the highest paleotemperature is compared with the homogenization temperature range of the ore-forming fluid in step (5). If the highest paleotemperature is within the homogenization temperature range of the ore-forming fluid, it is determined that the organic matter is contemporaneous with the early ore-forming fluid. If the highest paleotemperature is higher than the upper limit of the homogenization temperature range of the ore-forming fluid, it is determined that the organic matter experienced an earlier high-temperature thermal event. The homogenization temperature range of the ore-forming fluid in Cal3 is used to judge the cooling evolution trend of the ore-forming fluid. When the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal3, it is determined that the ore-forming fluid has evolved from early high temperature to late low temperature cooling.

[0046] In this invention, the conditions for the microscopic laser Raman spectroscopy test may include: a laser wavelength of 632.8 nm, an exposure time of 5–20 s, and a spectral range of 100–3000 cm⁻¹. -1 The spectral resolution is 0.6 cm⁻¹. -1 The spatial resolution was 400 nm, the ambient temperature was 22.3 °C, and the humidity was 35%.

[0047] In this invention, the asphalt may include intergranular asphalt filled with primary minerals, asphalt veinlets containing sulfides, and intergranular asphalt filled with hydrothermal vein minerals.

[0048] In this invention, the formula for calculating the highest paleotemperature (T, °C) is shown in Equation 1: T=737.3+320.9×R1-1067×R2-80.638×R1 2 Equation 1; Wherein, R1 is the peak intensity ratio of peak D (disorder peak) to peak G (graphite peak), and R2 is the peak area ratio of peak D to peak G; the Raman shift of peak D can be 1350 cm⁻¹. -1 The Raman shift of the G peak can be 1585 cm⁻¹.-1 .

[0049] After obtaining the comparison sample, the present invention extracts organic powder from the comparison sample; X-ray photoelectron spectroscopy is performed on the organic powder to obtain the aromatic carbon ratio, S / C atomic ratio and pyrrole nitrogen / pyridine nitrogen ratio of the organic matter, and to determine whether the organic matter alteration mechanism is caused by thermochemical sulfate reduction (TSR) or thermal alteration (TCA).

[0050] In this invention, the method for extracting organic powder from the comparative sample can be carried out in accordance with the national standard GB / T 19144-2010.

[0051] In this invention, the conditions for X-ray photoelectron spectroscopy (XPS) testing may include: an excitation source of Al Kα target, an excitation energy of 1486.6 eV, and a vacuum level of <5 × 10⁻⁶ eV in the XPS analysis chamber. -8 mbar; full spectrum scanning pass energy 100eV, step size 1eV; fine spectrum scanning pass energy 30eV, step size 0.05eV; spectral acquisition range 0~1350eV, X-ray beam spot diameter 400μm; C1s binding energy 284.8eV as internal standard correction.

[0052] In this invention, the method for determining whether the organic matter alteration mechanism is TSR or TCA includes: if the aromatic carbon atom ratio of the asphalt is ≥75%, the S / C atomic ratio is 0.035~0.17, and the pyrrole nitrogen / pyridine nitrogen ratio is ≥3, then the organic matter alteration mechanism is thermochemical sulfate reduction (TSR); if the aromatic carbon atom ratio of the asphalt is <75%, the S / C atomic ratio is <0.035, and the pyrrole nitrogen / pyridine nitrogen ratio is <3, then the organic matter alteration mechanism is thermal alteration (TCA).

[0053] Based on the results obtained in steps (1) to (6), this invention establishes a systematic analysis of the mineral formation sequence, ore-forming fluid evolution, and organic matter participation mode, and obtains the organic matter participation fluid ore-forming mode.

[0054] In this invention, the organic matter's participation in fluid mineralization can include three stages: Early mineralization stage: Low-temperature reducing hydrocarbon-rich fluids are injected to form ancient oil reservoirs, which are then reduced by bacterial sulfates to form H2S-rich fluids, which precipitate to form Py1 and Cal1; the temperature of the low-temperature reducing hydrocarbon-rich fluids can be 77.56~148.22℃, and Cal1 exhibits bright yellow cathodic luminescence; Early mineralization stage: High-temperature reducing basin brine fluids extract metallic substances, and the warming of ancient oil reservoirs transforms the participation of organic matter in mineralization into thermochemical sulfate reduction and thermal desulfurization of organic matter, accompanied by Cal2 precipitation and the formation of Py2, Sp1, Sp2 and Gn1; the temperature of the high-temperature reducing basin brine fluids can be 146.3~283.2℃. Late mineralization stage: High-temperature reducing basin brine fluid transforms into low-temperature mineralizing fluid, oxidizing atmospheric precipitation infiltrates and leaches, ancient oil reservoirs are destroyed, and mineralization consumes residual thermochemical sulfate reduction or organic matter thermal desulfurization of H2S; the temperature of the mineralizing fluid formed by the infiltration and leaching of the low-temperature oxidizing atmospheric precipitation can be 66.0~185.7℃.

[0055] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1 according to Figure 1 The technology roadmap shown is being studied.

[0057] (1) Field geological survey and sample collection Field geological profile observations were conducted at the target deposit to observe mineral morphology, occurrence, and interpenetration relationships, and to record the occurrence types of organic matter (solid bitumen, heavy oil, kerogen) and their spatial relationship with mineralized strata. Specifically, the spatial relationship refers to the fact that organic matter is mainly found in the Upper Triassic source rocks (T3s, T3m) and the Lower Cretaceous-Paleocene ore deposits (K1j, E1y), exhibiting various occurrences such as disseminated, massive, fissure-filled, veinlet, and vug-filled, and is closely associated with lead-zinc sulfide ore bodies in space.

[0058] Sample collection plan: Prioritize collecting drill core samples, supplemented by outcrop samples; collect comparative samples for mineralized zones and the periphery of ore bodies; samples should include lead-zinc sulfide ores, calcite gangue, and organic-containing ores. After core sample collection, perform detailed classification, description, and record of interrelationships. Perform lithological descriptions on hand specimens of drill and outcrop samples. Specifically, the lithological descriptions include: sandstone and breccia. Fifty thin sections will be examined under a microscope.

[0059] Early mineralization stage: characterized by the formation of disseminated pyrite (Py1) and cemented calcite (Cal1). Microscopic examination reveals Py1 replacing Cal1, indicating that Py1 occurred later than Cal1.

[0060] Early mineralization: characterized by the formation of disseminated galena (Gn1), disseminated sphalerite (Sp1), colloidal pyrite (Sp2), and colloidal sphalerite (Sp2), accompanied by coarse-grained calcite (Cal2). Colloidal mineralization often occurs in concentric rings, exhibiting a sequence of pyrite-sphalerite-coarse-grained calcite from the fracture wall towards the center.

[0061] Late mineralization: characterized by the formation of coarse-grained calcite veins (Cal3) and associated coarse-grained euhedral sphalerite (Sp3) and coarse-grained euhedral galena (Gn3). Cross-sections of the Gn3+Cal3 veins reveal early-stage minerals, and cathodoluminescence images show significant differences in calcite formation across the three phases (Cal1 is bright yellow and homogeneous, Cal2 is darker with occasional zoning, and Cal3 is dark red with significant oscillating zoning).

[0062] Preparation of rock thin sections (0.03 mm thick): sampling, grinding the surface, gluing the sections, grinding the sections to 0.03 mm, and polishing.

[0063] Preparation of probe sheets (thickness 0.035~0.05mm): sampling, gluing, surface grinding, sheet bonding, grinding to 0.035~0.05mm, polishing. Preparation of fluid inclusion sheets (thickness 0.1mm): sampling, surface grinding, sheet bonding, grinding to 0.1mm, polishing.

[0064] (2) Microscopic observation and cathodoluminescence imaging Polarization microscopy observation. A Leica DMLP polarization microscope was used to systematically observe the main minerals (pyrite, sphalerite, galena) and organic matter (solid bitumen) under transmitted single-polarized light, crossed polarized light, and reflected light. Mineral morphology (disseminated, colloidal, coarse-grained), bitumen optical structure (mosaic, homogeneous), and the interpenetration relationships between various minerals were identified. For samples with a large field of view (greater than the single imaging range of the microscope), a full-scanning SD-3000A rock thin section microscope was used for scanning, and the sections were stitched together using Power Mosaic software.

[0065] In the petrographic identification of the Jinding deposit, the interpenetration relationship specifically refers to the spatial cutting, dislocation, encapsulation, and replacement phenomena of mineral aggregates, organic veins, and hydrothermal veins of different generations. For example, coarse-grained galena-calcite veins cross-cut early disseminated or colloidal sulfides, sulfide-bearing bitumen veins are truncated by later calcite veins, and colloidal sphalerite grows around the core of early pyrite. These interpenetration and encapsulation structures directly indicate the relative time sequence of mineral formation and provide key petrographic criteria for determining the three-stage evolution sequence of pre-mineralization, early-mineralization, and late-mineralization.

[0066] Figure 2The diagram shows the microscopic characteristics of metallic sulfides under reflected light. In this diagram, a represents disseminated pyrite, b represents disseminated sphalerite and galena, c represents colloidal pyrite (Py2) and colloidal sphalerite (Sp2), often distributed in concentric ring structures, d represents colloidal pyrite (Py2) growing around pyrite (Pre-Py), and e represents disseminated pyrite and sphalerite in the early stage of a Gn3+Cal3 vein cross-section. This indicates that the Jinding lead-zinc mineralization can be divided into three stages: pre-mineralization, early-mineralization, and late-mineralization.

[0067] Cathodoluminescence imaging. Using a CL8200 MK5-2 cathodoluminescence analyzer (accelerating voltage 5~10kV, beam current 0.5mA, vacuum 80~120mTorr), cathodoluminescence imaging of gangue mineral calcite was performed using a DM2500P microscope. Different calcite phases (Cal1, Cal2, Cal3) were distinguished based on their luminescence color and zoning characteristics. In the early mineralization stage, Cal1 exhibited bright yellow cathodoluminescence with uniform internal banding, indicating replacement by Py1. Early mineralization stage Cal2 showed dimmer luminescence with occasional weak zoning, filling the ends of colloidal sulfide sequences. Late mineralization stage Cal3 emitted dark red luminescence with significant oscillating zoning, its veins intersecting early mineral assemblages. Polarization microscopy was used to observe the interpenetration relationships and occurrence of each mineral to determine the mineralization phase. The intensity and color of cathodoluminescence in carbonate minerals are related to those of Mn. 2+ and Fe 2+ Content, and Mn 2+ / Fe 2+ The quantitative relationship of the values ​​is as follows: excluding Mn 2+ Fe 2+ It is also usually rare, Mn 2+ / Fe 2+ Zero, no light emitted; 0.05 <Mn 2+ / Fe 2+ <0.2, dim luminescence intensity, orange-red luminescence color; 0.2 <Mn 2+ / Fe 2+ <2, moderate luminescence intensity, orange-yellow emission color; Mn 2+ / Fe 2+ >2. Bright luminescence intensity, bright yellow luminescence color. Mn 2+ and Fe 2+ Content, and Mn 2+ / Fe 2+ These three factors—luminescence intensity and color—jointly control the brightness and color of cathodoluminescence. Only when the three reach a suitable ratio will the luminescence be brightest and the color most vivid. However, overall, Mn... 2+ / Fe 2+The control effect is stronger. Bright yellow → dark → dark red represent Cal1, Cal2, and Cal3 respectively. Cal1, Cal2, and Cal3 represent the early mineralization stage of Cal1; the early mineralization stage of Cal2; and the late mineralization stage of Cal3.

[0068] Figure 3 The image shows the cathodoluminescence characteristics of calcite. It can be seen that in the early stages of mineralization, Cal1 exhibits the brightest cathodoluminescence color (bright yellow) and a uniform internal structure, lacking zonal structures (see...). Figure 3 (a) In the late mineralization stage, Cal3 exhibits the darkest cathodoluminescence color (dark red) and clearly distinguishable oscillating zoning characteristics (see [reference]). Figure 3 (b) Figure 3 In the middle c and d, Cal2, which is associated with colloidal mineralization in the early stage of mineralization, has a darker cathodic emission color compared with Cal1, and occasionally an indistinct oscillating ring can be seen; Figure 3 In the middle, e and f are Sp3 minerals with a high degree of euhedrality, exhibiting a translucent crystalline structure. This indicates the order of formation of the main ore minerals and gangue minerals in the Jinding deposit.

[0069] The purpose of this step is to redefine the mineral formation sequence in different mineralization stages (pre-mineralization, early mineralization, and late mineralization) through mineral morphology observation and cathodoluminescence imaging, providing a basis for the division of stages in subsequent steps.

[0070] Based on the mineralization stages of the Jinding deposit, the stages of each major mineral are determined as follows: Pyrite in the early mineralization stage (Py1) is fine-grained disseminated, often replacing early calcite cement; in the early mineralization stage (Py2), it is characterized by a colloidal concentric ring structure, growing around the core of Py1; in the late mineralization stage (Py3), it is a coarse-grained euhedral veinlet, cutting through the early sulfide aggregate. Sphalerite in the early mineralization stage occurs as disseminated (Sp1) and colloidal rings (Sp2), forming a growth sequence of "pyrite → sphalerite → calcite" with coarse-grained calcite (Cal2); in the late mineralization stage (Sp3), it evolves into coarse-grained subhedral crystals containing abundant fluid inclusions. Galena in the early stage (Gn1) is disseminated or granular, distributed within the colloidal sphalerite ring; in the late stage (Gn3), it forms veins that cut through the early structure with coarse-grained calcite. The generational division of calcite is the most intuitive: the early mineralization cement (Cal1) emits a bright yellow cathodic luminescence and is uniform without internal banding, and is replaced by Py1; the early mineralization coarse-grained calcite (Cal2) emits a darker luminescence and occasionally shows weak banding, filling the end of the colloidal sulfide sequence; the late mineralization vein calcite (Cal3) emits a dark red luminescence and develops significant oscillating banding, and its veins cut through the early mineral assemblages.

[0071] (3) In-situ micro-area trace element and rare earth element analysis by LA-ICP-MS (a) Test objects and equipment: LA-ICP-MS in-situ micro-area analysis was performed on pyrite (Py1, Py2, Py3), sphalerite (Sp1, Sp2, Sp3), and calcite (Cal2, Cal3) from different phases divided in step (2) to obtain the content test results of trace elements and rare earth elements. The LA (laser ablation system) in LA-ICP-MS was a Geolas 193nm excimer fixed laser manufactured by Coherent, and the ICP-MS (inductively coupled plasma mass spectrometry system) was an Element XR high-resolution inductively coupled plasma mass spectrometer manufactured by Thermal Fisher.

[0072] (b) Test parameters: The carrier gas for laser ablation is He, and the compensating gas is Ar; the laser frequency is 8~10Hz, and the energy is 6~10J / cm. 2 The beam spot diameter was 44 μm; each point was sampled for 100 s (background for the first 20 s, sample signal for 50 s); elemental content was calculated using multiple external standards and total normalization; pyrite and sphalerite standard samples were NIST SRM 610, NIST SRM 612, BHVO-2G, BIR-1G, and USGS MASS-1; calcite standard samples were NIST SRM 610, NIST SRM 612, BHVO-2G, CRM, and JCT; the relative error of the test results was <10%.

[0073] (c) Experimental results are shown in Figures 4-8 In the study of the Jinding lead-zinc deposit, by processing multiple geochemical indicators of pyrite, sphalerite, and calcite, and combining the environmental indicative significance of each indicator, the temperature evolution, redox state, and material source of the ore-forming fluid were systematically reconstructed.

[0074] Regarding temperature, based on the principle that the Zn / Cd value of sphalerite is positively correlated with the formation temperature, the average Zn / Cd value of sphalerite for three generations was calculated ( Figure 4 The early disseminated Sp1 was 186 and the colloidal Sp2 was 158, indicating a medium-high temperature environment; the late coarse-grained Sp3 dropped to 97, reflecting a systematic decrease in mineralization temperature.

[0075] The redox state was determined using the redox sensitivity of calcite Fe content. The study observed a sharp increase in Fe content from the early to late stages of mineralization, along with changes in the Fe-Mn-Mg triangulation of calcite. Figure 5 In the data, the movement of data points toward the Fe-Mn endmember (reduction zone) indicates an increase in the oxidizing properties of the fluid. Together with the increase in Mo and Fe content, this marks the node where the ore-forming fluid transitions from early reduction to late oxidation.

[0076] The tracer of fluid origin is based on the rare earth element distribution pattern and the Y / Ho ratio. The Y / Ho value for marine sediments is typically 44–74, while that for sediments associated with terrigenous clastic or volcanic ash is 26–28. A Y / Ho ratio greater than 28 and less than 44 indicates a mixed source of marine sediments and terrigenous clastic or volcanic ash. The total rare earth element content (ΣREE) in calcite ranges from 4.43 to 685 μg / g, generally exhibiting a right-sloping LREE enrichment pattern. Cal2 shows a stronger right-sloping pattern, while Cal3 not only shows a weakened enrichment but also exhibits relative MREE enrichment; in terms of Y / Ho... - In the La / Ho diagram, Cal2 exhibits characteristics of both marine carbonate rocks and terrigenous clastic rocks, while Cal3 is clearly shifted to the terrigenous clastic endmember, revealing that late-stage ore-forming fluids superimposed atmospheric precipitation leaching of the red-bed clastic rocks in the Lanping Basin. The enrichment of Fe and Sn in late-stage calcite and sphalerite further corroborates this transformation. The determination of the ore-forming source integrates the genetic determination of pyrite's S / Se ratio and trace element evolution, as well as the magmatic differentiation indicators of sphalerite's Ga / In and Ge / In ratios. Magmatic sulfides typically have S / Se values ​​<15000, while hydrothermal sulfides range from 10000 to 28000. In this study, the S / Se values ​​of Py1 and Py2 both fall within the hydrothermal range. The trace element composition of pyrite (Py1) changes from Pb-Ag-Ti-V enrichment in the early stage to Mo-Tl-Mn-Zn-As enrichment in the middle stage of colloidal pyrite (Py2), and then to Mn-Zn-As-Pb enrichment in the late stage; in particular, the significant enrichment of high-temperature elements such as Mo, Mn, Zn, and As (Mo: 0.41~118 μg / g in Py1, 205~3813 μg / g in Py2; Mn: 6.19~557 μg / g in Py1, 3019~20389 μg / g in Py2; Zn: 4.74~69.8 μg / g in Py1, 38.3~187 μg / g in Py2; As: 178~4721 μg / g in Py1, 1230~14847 μg / g in Py2) indicates the involvement of deep heat source fluids. Figures 6-7 ).

[0077] Figure 8 The diagram shows the Ga / In and Ge / In content ratios of sphalerite in rock samples from wells Zk502 and Zk1403 in the Beichang mining area of ​​the Jinding deposit. It reveals that the Ga / In ratio of sphalerite during the same period ranges from 4.79 to 7816, and the Ge / In ratio ranges from 4.88 to 8400. In was not detected in some samples, which is contrary to the characteristics of magmatic fluid injection (Ga / In < 1, Ge / In < 0.1), thus ruling out direct magmatic fluid injection. Based on this evidence, it is proposed that the ore-forming mechanism involves magmatic activity acting merely as a "thermal engine," driving basin fluid infiltration and heating, extracting ore-forming metallic elements from deep surrounding rocks, and ultimately forming a hydrothermal mineralization system.

[0078] (4) LA-MC-ICP-MS in-situ sulfur isotope (δ¹²) micro-regions of sulfides 34 S) Analysis Test Equipment and Parameters: LA-MC-ICP-MS sulfide sulfur isotope testing was performed at Nanjing Hongchuang Geological Exploration Technology Service Co., Ltd. The LA system used a 193nm ArF excimer laser emitter (Resolution SE model) manufactured by Applied Spectra, USA. The MC-ICP-MS system used a Neptune Plus multi-receiver inductively coupled plasma mass spectrometer manufactured by Thermo Fisher Scientific. He was used as the carrier gas and Ar as the compensating gas during laser ablation. The laser frequency was set to 5Hz, and the energy was set to 4J / cm². 2 The beam spot diameter was 50 μm. During the test, 20 seconds of background signal were collected first, followed by 30 seconds of sample signal. Sulfur isotope mass fractionation was corrected using the SSB method, with Wenshan pyrite (δ¹⁸O₂) as the reference. 34 S = +1.5‰ V-CDT) was used as the external standard. During the testing process, the NIST SRM 123 standard sample (δ) was used. 34 S = +17.1‰) is used to ensure the reliability of the data.

[0079] Test subjects: Based on the phases defined in step (2), pyrite (disseminated Py1, colloidal Py2, coarse-grained vein Py3) and sphalerite (disseminated Sp1, colloidal Sp2, coarse-grained vein Sp3) with different occurrences were selected from the thin sections for in-situ sulfur isotope determination. Based on the phases defined in step (2), pyrite (Py1, Py2, Py3) and sphalerite (Sp1, Sp2, Sp3) with different occurrences were selected from the thin sections for in-situ sulfur isotope determination using LA-ICP-MS in-situ micro-area analysis.

[0080] The experimental results are shown in Figure 9 In sulfur isotope tracing studies, existing testing methods include whole-rock powder analysis and in-situ micro-area analysis (such as in-situ SIMS and in-situ LA-(MC)ICP-MS). The sulfur isotope data for the Jinding deposit cited partially employ whole-rock powder analysis; however, this method, due to the mixing of mineral grains from multiple mineralization generations, is prone to contamination from different sulfur sources. To accurately define the sulfur source and its relative contribution for each mineralization stage, this invention employs LA-MC-ICP-MS in-situ micro-area δ¹⁴ spectral density analysis. 34 The S-analysis method obtains the sulfur isotope composition of metal sulfides point by point according to the phase (Py1 / Py2 / Py3, Sp1 / Sp2 / Sp3), which avoids phase contamination caused by the traditional whole rock powder method from a mechanism perspective.

[0081] Figure 9The sulfur isotope data of the Jinding deposit cited in this paper are from the following sources: The sulfur isotope data of the Jinding sphalerite cited in this paper are from the following literature: [1] Qin Gongjiong, Zhu Shangqing. Genetic model and prospecting prediction of Jinding lead-zinc deposit [J]. Yunnan Geology, 1991, 10(2): 145-189. [2] Yin Jing. Isotope geochemical characteristics and ore-forming fluid evolution of Lanping Jinding lead-zinc deposit [D]. Kunming: Kunming University of Science and Technology, 2013. [3] Zhou Weiquan, Zhou Quanli. Study on lead and sulfur isotope composition of Lanping lead-zinc deposit [J]. Geochemistry, 1992, 6(2): 141-148. [4]Yalikun Y, Xue C, Dai Z, et al. Microbial structures and possible bacterial sulfide fossils in the giantJinding Zn-Pb deposit, Yunnan, SW-China: Insights into the genesis of Zn-Pbsulfide mineralization[J]. Ore Geology Reviews, 2018, 92: 61-72. [5]Li M, LiuS, Xue C, et al. Zinc, cadmium and sulfur isotope fractionation in asupergiant MVT deposit with bacteria[J]. Geochimica et Cosmochimica Acta, 2019, 265: 1-18. [6] Tang Y, Bi X, Fayek M, et al. Microscale sulfur isotopic compositions of sulfide minerals from the Jinding Zn–Pb deposit, Yunnan Province, Southwest China[J]. Gondwana Research, 2014, 26(2): 594-607. [7] Li Xiangcai, Wang Jingbin, Zhu Xinyou, et al. Fine characterization of mineralization process in the Jinding lead-zinc deposit in Lanping, western Yunnan: evidence from in-situ trace elements and S-Pb isotopes of sulfides[J]. Acta Petrologica Sinica, 2023, 39(8): 2511-2532. [8] Wang Zhe. Study on ore-forming fluids and mineralization mechanism of the Jinding lead-zinc deposit in Yunnan[D]. Beijing: China University of Geosciences (Beijing), 2013.[9] Dai Zhijie. Sulfide microbial structures and bacterial fossils and their metallogenic significance in the Jinding super-large lead-zinc deposit [D]. Beijing: China University of Geosciences (Beijing), 2020.

[10] Ye Qingtong, Hu Yunzhong, Yang Yueqing. Regional geochemical background and mineralization of gold, silver, lead and zinc in the Sanjiang area [M]. Beijing: Geological Publishing House, 1992: 21-264.

[11] Luo Junlie, Yang Jingzhou. Evolution of the Tethys in western Yunnan and mineralization of major metal deposits [M]. Beijing: Geological Publishing House, 1994.

[12] Chen Yinghui. Sulfur isotope geochemical characteristics and their metallogenic significance in the Jinding lead-zinc deposit in Yunnan [D]. Beijing: China University of Geosciences (Beijing), 2016. The sulfur isotope data of the Jinding galena cited are from the following literature:

[13] Qin Gongjiong, Zhu Shangqing. Genetic model and prospecting prediction of Jinding lead-zinc deposit [J]. Yunnan Geology, 1991, 10(2): 145-189.

[14] Yin Jing. Isotope geochemical characteristics and ore-forming fluid evolution of Lanping Jinding lead-zinc deposit [D]. Kunming: Kunming University of Science and Technology, 2013.

[15] Zhou Weiquan, Zhou Quanli. Study on lead and sulfur isotope composition of Lanping lead-zinc deposit [J]. Geochemistry, 1992, 6(2): 141-148.

[16] Yalikun Y, Xue C, Dai Z, et al. Microbial structures and possiblebacterial sulfide fossils in the giant Jinding Zn-Pb deposit, Yunnan, SW-China: Insights into the genesis of Zn-Pb sulfide mineralization[J]. OreGeology Reviews, 2018, 92: 61-72.

[17] Tang Y, Bi

[18] Li Xiangcai, Wang Jingbin, Zhu Xinyou, et al. Fine characterization of mineralization process in Lanping Jinding lead-zinc deposit in western Yunnan: evidence from in-situ trace elements and S-Pb isotopes of sulfides [J]. Acta Petrologica Sinica, 2023, 39(8): 2511-2532.

[19] Wang Zhe. Study on ore-forming fluids and mineralization mechanism of Jinding lead-zinc deposit in Yunnan Province [D]. Beijing: China University of Geosciences (Beijing), 2013.

[20] Ye Qingtong, Hu Yunzhong, Yang Yueqing. Regional geochemical background and mineralization of gold, silver, lead and zinc in the Sanjiang area [M]. Beijing: Geological Publishing House, 1992: 21-264.

[21] Luo Junlie, Yang Jingzhou. Evolution of Tethys in western Yunnan and mineralization of major metal deposits [M]. Beijing: Geological Publishing House, 1994.

[22] Chen Yinghui. Sulfur isotope geochemical characteristics and mineralization significance of Jinding lead-zinc deposit in Yunnan Province [D]. Beijing: China University of Geosciences (Beijing), 2016. The sulfur isotope data of Jinding pyrite cited are from the following literature:

[23] Qin Gongjiong, Zhu Shangqing. Genetic model and prospecting prediction of Jinding lead-zinc deposit [J]. Yunnan Geology, 1991, 10(2): 145-189.

[24] Zhou Weiquan, Zhou Quanli. Study on lead and sulfur isotope composition of Lanping lead-zinc deposit [J]. Geochemistry, 1992, 6(2): 141-148.

[25] Yalikun Y, XueC, Dai Z, et al. Microbial structures and possible bacterial sulfide fossils in the giant Jinding Zn-Pb deposit, Yunnan, SW-China: Insights into the genesis of Zn-Pb sulfide mineralization [J]. Ore Geology Reviews, 2018, 92:61-72.

[26] Tang Y, Bi X, Fayek M, et al. Microscale sulfur isotopic compositions of sulfide minerals from the Jinding Zn–Pb deposit, Yunnan Province, Southwest China[J]. Gondwana Research, 2014, 26(2): 594-607.

[27] Li Xiangcai, Wang Jingbin, Zhu Xinyou, et al. Fine characterization of mineralization process in the Jinding lead-zinc deposit in western Yunnan: evidence from in-situ trace elements and S-Pb isotopes of sulfides[J]. Acta Petrologica Sinica, 2023, 39(8): 2511-2532.

[28] Wang Zhe. Study on ore-forming fluids and mineralization mechanism of the Jinding lead-zinc deposit in Yunnan[D]. Beijing: China University of Geosciences (Beijing), 2013.

[29] Huang Shiqiang. Interaction between organic fluids and surrounding rocks / evaporites in the Jinding super-large lead-zinc deposit and its significance for mineralization [D]. Beijing: China University of Geosciences (Beijing), 2020.

[30] Ye Qingtong, Hu Yunzhong, Yang Yueqing. Regional geochemical background and mineralization of gold, silver, lead and zinc in the Sanjiang area [M]. Beijing: Geological Publishing House, 1992: 21-264.

[31] Luo Junlie, Yang Jingzhou. Evolution of the Tethys in western Yunnan and mineralization of major metal deposits [M]. Beijing: Geological Publishing House, 1994.

[32] Chen Yinghui. Sulfur isotope geochemical characteristics and mineralization significance of the Jinding lead-zinc deposit in Yunnan [D]. Beijing: China University of Geosciences (Beijing), 2016. Figure 9 The other data are sulfur isotope data test data of the present invention.

[0082] In terms of data interpretation, based on the fractionation principle of different sulfur source reaction mechanisms, a three-stage discrimination criterion is established: (i) BSR discrimination—bacterial sulfate reduction is controlled by kinetic fractionation, and the fractionation amplitude is extremely large, resulting in the generation of H2S and precipitated sulfides δ 34 S is significantly negative and dispersed, and the fractionation of coexisting sulfates is usually 2-42‰. (ii) TSR discrimination—Thermochemical sulfate reduction occurs under high temperature (>100℃) conditions, and isotopic fractionation is significantly reduced (usually 0-20‰), producing sulfides δ 34 S tends to be positive. Therefore, when the late-stage sulfides (Py3, Sp3) δ... 34 When the S value is enriched towards heavy sulfur and accompanied by evidence of high temperature in fluid inclusions, TSR is comprehensively determined to be the dominant mechanism. (iii) TDS discrimination and scale assessment—δ of H2S generated by thermal desulfurization of organic matter 34 S values ​​typically fall within the characteristic range of -5 to 0‰. If the δ of the sulfide... 34 The presence of independent peaks within this range in the S-histogram, combined with field observations confirming the close spatial association of corresponding sulfides with organic-rich strata, indicates a TDS contribution. Based on this, the mineralization amount corresponding to the TDS peak is compared with the total mineralization of the entire area to quantitatively assess its mineralization scale. Given the total lead-zinc metal reserves of approximately 15 million tons in the Jinding deposit, and assuming lead ore (PbS) accounts for 20% (approximately 3 million tons) and zinc ore (ZnS) accounts for 80% (approximately 12 million tons), if we consider that one-third of the sulfur in all lead-zinc ores comes from organic matter pyrolysis, then the cumulative sulfur supply from TDS is approximately 1.453 million tons (equivalent to approximately 1.544 million tons of H2S). This quantitatively constrains the contribution of organic matter pyrolysis to mineralization from a material balance perspective.

[0083] (5) Calcite fluid inclusion thermometry experiment Test equipment and conditions: The LinkAm THMSG600 hot and cold stage (measurement range -160~350℃) was used. The ambient temperature was 20~25℃ and the relative humidity was 30~50%.

[0084] Temperature measurement procedure: First, the temperature was lowered to -160℃ in stages, then raised to the temperature in stages until the inclusions were completely homogenized. The temperature was then lowered until bubbles reappeared, and then raised to homogenization again. If the difference between the two homogenization temperatures was >1℃, the temperature was measured again; if the difference was <1℃, the average value was taken. Because the fluid inclusion volume in the samples in this experiment was generally small (<10μm), the freezing point temperature error was relatively large and was not used as the main data.

[0085] The experimental results are shown in Figure 10 Based on the phases divided in step (2), inclusion thermometry was performed on coarse-grained calcite (Cal2) in the early mineralization stage and vein-like calcite (Cal3) in the late mineralization stage. Combined with the rare earth element data of calcite, the fluid temperature ranges of different mineralization stages were comprehensively determined (Cal2: 146.3~283.2℃; Cal3: 66.0~185.7℃). The data processing and judgment methods are as follows: (i) Data screening and quality control: points with an error of >1℃ between two homogenization temperature measurements were removed; for the same thin section of calcite in the same phase, the number of effective measurement points should be ≥15, otherwise additional tests should be conducted; if there is a significant double homogenization temperature (the difference between the homogenization temperatures of the two heating phases is >5℃), it should be discarded. (ii) Histogram statistics and temperature range determination: frequency histograms were plotted with the effective homogenization temperature values ​​of Cal2 and Cal3 at a group interval of 5℃. Figure 10 The peak temperature represents the main temperature of the fluid in this period, and the range of one standard deviation to the left and right of the peak is used as the temperature range of the ore-forming fluid. The peak temperature of Cal2 is higher than that of Cal3, which is used to demonstrate the cooling evolution trend of the ore-forming fluid from early high temperature to late low temperature. (iii) Paleotemperature determination: The highest paleotemperature of the asphalt obtained by Raman spectroscopy in the subsequent step (6) (calculated by Equation 1) is compared with the homogeneous temperature range of Cal2 ore-forming fluid (146.3~283.2℃). If the Raman temperature falls within the homogeneous temperature range of Cal2 ore-forming fluid, it is determined that the organic matter and the early ore-forming fluid experienced the same thermal event at the same time. If the Raman temperature is higher than the upper limit of Cal2 temperature, the organic matter experienced an earlier high-temperature thermal event, which is different from the source of the ore-forming fluid. (iv) Fluid pressure estimation (auxiliary): If the freezing point temperature determination is valid (inclusions > 10 μm), the fluid salinity (mass fraction) can be calculated from the freezing point temperature using the NaCl-H2O phase diagram. Then, the capture pressure can be calculated by combining the homogenization temperature with the phase diagram to further estimate the mineralization depth. If the freezing point determination error is too large, this item is only for qualitative reference. The calculation results show that the highest paleotemperature (T2 value) experienced by this type of bitumen is 77.56~148.22℃, which coincides with the low-temperature peak in the homogenization temperature histogram of calcite fluid inclusions, representing the fluid temperature in the early stage of mineralization.

[0086] (6) Organic matter testing and analysis (microscopic laser Raman spectroscopy + X-ray photoelectron spectroscopy) (a) Microscopic laser Raman spectroscopy (LR): Performed on a LabRAM HR microscopic confocal laser Raman spectrometer (laser wavelength 632.8 nm, exposure time 5–20 s, spectral range 100–3000 cm⁻¹). -1 Spectral resolution 0.6 cm -1 Spatial resolution 400 nm, ambient temperature 22.3℃, humidity 35%. Three types of bitumen with different occurrences (intergranular bitumen infilled with primary minerals, sulfide-containing bitumen veinlets, and intergranular bitumen infilled with hydrothermal veins) were tested in thin sections and inclusion sections containing organic rocks, with the D peak (1350 cm⁻¹) as the dividing line. -1 ) and G peak (1585cm) -1 The peak intensity ratio (R1) and peak area ratio (R2) characterize the highest paleotemperature (°C) experienced by organic matter, as shown in Equation 1. Figure 11 .

[0087] T=737.3+320.9×R1-1067×R2-80.638×R1 2 Equation 1.

[0088] (b) Extraction of organic matter from ore: carried out in accordance with national standard GB / T 19144-2010.

[0089] (c) X-ray photoelectron spectroscopy (XPS): A Thermo Scientific K-Alpha X-ray photoelectron spectrometer (monochromatic Al Kα target, excitation energy 1486.6 eV) was used. Approximately 2 mg of organic powder was adhered to double-sided adhesive and pressed into a pellet; before analysis, the XPS analysis chamber was evacuated to an ultra-high vacuum (<5 × 10⁻⁶). -8 mbar); full spectrum scanning pass energy 100 eV, step size 1 eV; narrow spectrum (fine spectrum) scanning pass energy 30 eV, step size 0.05 eV; spectral acquisition range 0~1350 eV, X-ray beam spot diameter 400 μm.

[0090] XPS data processing: Advantage software was used, with C1s binding energy (284.8 eV) as the internal standard for correction. After background subtraction, mixed Gaussian-Lorentz line-type peak fitting was performed. The following information was obtained by integrating the area of ​​each sub-peak: XPS fitted spectrum of organic carbon (1s) (C1s spectrum, see...) Figure 12 From this, we can see that 284.8 eV (CC, CH bonded carbon), 286.0 ± 1 eV (CO, C=O bonded carbon), and 290.0 ± 0.5 eV (π-π bonded carbon). Vibration peaks, reflecting the proportion of aromatic carbons); XPS fitting spectrum of organic matter nitrogen (1s) (N1s spectrum, Figure 13 ): 398.6±0.5eV (pyridine nitrogen), 400.2±0.5eV (pyrrole nitrogen), 401.4±0.5eV (tetravalent nitrogen / graphite nitrogen); Organic sulfur (2p) XPS fitted spectrum (S2p spectrum, Figure 14 ): 161.5 eV (sparkling zinc / chalcopyrite), 162.5 ± 0.5 eV (pyrite), 163.5 eV (aliphatic organosulfur compounds), 164.1 ± 0.1 eV (thiophene sulfur compounds), 165.3 ± 0.3 eV (sulfoxide), 169 eV (sulfate); Organic matter oxygen (1s) XPS fitted spectrum (O1s spectrum, Figure 15 ): 530 eV (metal oxide), 531.5 eV (C=O), 533.4 eV (CO).

[0091] By comparing the organic sulfur content (S / C atomic ratio), aromatic carbon atom ratio, and pyrrole nitrogen / pyridine nitrogen ratio with data from known TSR-origin asphalt (Brazeau River region, Canada; LaBarge gas field, USA) and TCA-origin asphalt (Brooks Mountains, USA), the asphalt alteration mechanism (TSR or TCA) was determined. The Raman spectral data processing method is as follows: (i) Spectrum preprocessing: Baseline subtraction was performed on the Raman spectra of each asphalt sample using LabSpec or Origin software (using polynomial fitting method), and then the D peak (~1350 cm⁻¹) was preprocessed. -1 ) and G peak (~1585 cm) -1(ii) Paleoreservoir temperature calculation: Substitute R1 and R2 into Equation 1. (iii) Correlation of mineralization periods: Compare the paleotemperature calculation results of the three types of bitumen (primary intergranular bitumen, sulfide-containing bitumen veinlets, and hydrothermal vein bitumen) with the homogenization temperature of fluid inclusions in step 5. If the occurrence correspondence is consistent (e.g., the paleotemperature of hydrothermal vein bitumen is within the homogenization temperature range of the mineralization fluid in Cal2), it further corroborates that the bitumen of this occurrence is contemporaneous with the mineralization hydrothermal fluid. The XPS data processing and organic matter alteration mechanism determination method is as follows: (i) Element ratio calculation: The experimental data analysis and fitting were performed using Advantage software. The binding energy of each element was corrected using the binding energy of C1s (284.8 eV) as an internal standard. After background subtraction, the obtained raw data was fitted with mixed Gaussian-Lorentz line type. The content of functional groups of each element in the organic matter was obtained by the integral area of ​​each sub-peak, and the elemental composition information of the organic matter could also be obtained. (ii) Comparison and discrimination: Thermochemical sulfate reduction (TSR) asphalt and thermochemical alteration (TCA) asphalt showed significant differences in several key indicators. In this invention, the asphalt sample from Jinding Mine showed TCA characteristics, while the TSR characteristics were not significantly preserved. Figure 16 ). Existing data on TSR-origin and TCA-origin bitumen can be found in the following references:

[33] Kelemen SR, Walters CC, Kwiatek PJ, et al. Distinguishing solid bitumens formed by thermochemical sulfate reduction and thermal chemical alteration[J]. Organic Geochemistry, 2008, 39(8): 1137-1143.

[34] Kelemen SR, Walters CC, Kwiatek PJ, et al. Characterization of solid bitumens originating from thermal chemical alteration and thermochemical sulfate reduction[J]. Geochimica et Cosmochimica Acta, 2010, 74(18): 5305-5332.

[0092] (7) Construction of the model of organic matter participating in fluid mineralization Phase 1: Pre-mineralization stage Fluid properties and sources: The ore-forming fluid is a low-temperature (77.56~148.22℃), reducing hydrocarbon-rich fluid, which originates from the mature hydrocarbon expulsion of Upper Triassic source rocks (mainly marine algae mixed with terrestrial higher plants) in the basin.

[0093] Organic matter reaction mechanism: Hydrocarbon-rich fluids were injected into the Golden Dome structure to form ancient oil reservoirs. Under low-temperature and oxygen-deficient conditions, sulfates in the reservoir underwent BSR (bacterial sulfate reduction) by sulfate-reducing bacteria, forming H2S-rich fluids. Precipitation formed disseminated pyrite (Py1) and cemented calcite (Cal1). Py1 is relatively enriched in elements from the reservoir host rocks, such as Pb, Ag, Ti, and V. Sulfides at this stage have extremely negative δ... 34 The S value indicates that calcite (Cal1) exhibits a bright yellow cathodic emission.

[0094] Second stage: Early mineralization stage Fluid properties and sources: Regional alkaline magmatic activity led to an increase in geothermal gradient. The ore-forming fluid transformed into high-temperature (146.3~283.2℃), reducing basin brine. Through extraction of metallic substances from deep marine strata and concealed rock bodies in the basin, elements such as Mo, Tl, Mn, Zn, and As were relatively enriched. The increase in paleooil reservoir temperature (>80℃) led to the cessation of BSR. The way organic matter participated in mineralization transformed into: (1) TSR (thermochemical sulfate reduction): occurring in local high-temperature areas, with limited scale. (2) TDS (organic pyrolysis): TDS is formed by the δ-H2S. 34 The estimated sulfur (S) values ​​(-5‰ to 0‰) coincide with the peaks of the disulfide isotopes. Accompanying the precipitation of coarse-grained calcite (Cal2), colloidal pyrite (Py2), disseminated and colloidal sphalerite (Sp1, Sp2), and galena (Gn1) are formed. The high Zn / Cd ratio (158–186) in sphalerite indicates high temperature. Sulfides δ 34 The S value gradually increases, reflecting the contribution of TSR and / or TDS. Calcite (Cal2) cathodoluminescence is dim, and the Y / Ho value indicates marine origin, suggesting the fluid is reducing.

[0095] Third stage: Late mineralization stage Fluid properties and source: With the overall uplift of the basin and the decrease in the geothermal gradient, the ore-forming fluids transformed into low-temperature (66.0~185.7℃), oxidizing atmospheric precipitation. The fluids infiltrated and leached the shallow terrestrial red clastic strata of the basin, resulting in relative enrichment of Fe, Sc, Th, V, and REE. Sulfides δ... 34 The S value is higher than that of the previous two stages.

[0096] Organic matter formation mechanism: The uplift and destruction of the ancient oil reservoir has ceased BSR, TSR, and TDS processes. Mineralization primarily consumes residual TSR / TDS-derived H2S from the ancient oil reservoir.

[0097] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A comprehensive method for identifying the participation of organic matter in fluid mineralization, comprising the following steps: (1) Conduct field geological surveys at the target deposit, and collect core samples and outcrop samples as comparative samples for mineralized sections and the periphery of the ore body. The types of comparative samples include lead-zinc metal sulfide ores, calcite gangue and organic matter-containing sections; divide the mineralization stages into pre-mineralization, early-mineralization and late-mineralization stages; prepare rock thin sections, probe sections and fluid inclusion sections from the comparative samples; (2) Polarization microscopy was used to observe the ore minerals, gangue minerals and organic matter on the thin rock section. The luminescence characteristics of calcite were obtained by cathodic emission imaging on the thin rock section. The mineral formation sequence was determined based on the results of the polarization microscopy and the luminescence characteristics of calcite, and the different phases of pyrite, sphalerite, calcite and galena in the mining area were divided. The correspondence between the mineralization stages and mineral periods is as follows: Early mineralization stage: disseminated pyrite, denoted as Py1; cemented calcite, denoted as Cal1; Early mineralization stage: colloidal pyrite, designated Py2; disseminated sphalerite, designated Sp1; colloidal sphalerite, designated Sp2; coarse-grained calcite, designated Cal2; disseminated galena, designated Gn1; Late mineralization stage: coarse-grained euhedral pyrite, designated Py3; coarse-grained euhedral sphalerite, designated Sp3; coarse-grained calcite veins, designated Cal3; coarse-grained euhedral galena, designated Gn3; (3) On the probe sheet, laser ablation inductively coupled plasma mass spectrometry is used to perform in-situ micro-area trace element and rare earth element content analysis on pyrite, sphalerite and calcite of different periods divided in step (2). The mineral genesis is determined by the S / Se content ratio of pyrite and sphalerite, the mineralization temperature evolution is determined by the Zn / Cd content ratio of sphalerite, the fluid redox properties are determined by the Fe-Mn-Mg triangular component projection of calcite, and the fluid source is traced by the rare earth element distribution pattern and Y / Ho content value of calcite. (4) On the probe sheet, in-situ sulfur isotope δ¹⁴ spectroscopy was performed on the pyrite and sphalerite from different phases divided in step (2) using laser ablation multi-receiver inductively coupled plasma mass spectrometry. 34 S-analysis, through δ 34 The variation trend of S in different mineralization stages is used to identify the sulfur source reaction mechanism, which includes one or more of bacterial sulfate reduction, thermochemical sulfate reduction and organic matter thermal desulfurization. (5) On the fluid inclusion sheet, the homogenization temperature of the fluid inclusions in Cal2 and Cal3 divided in step (2) is measured to obtain the homogenization temperature range of the ore-forming fluids of Cal2 and Cal3 respectively. (6) Microscopic laser Raman spectroscopy is performed on the thin rock section to obtain the highest paleotemperature experienced by the asphalt; the highest paleotemperature is compared with the homogenization temperature range of the ore-forming fluid in step (5). If the highest paleotemperature is within the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid is contemporaneous with the early ore-forming fluid. If the highest paleotemperature is higher than the upper limit of the homogenization temperature range of the ore-forming fluid, it is determined that the organic fluid experienced an earlier high-temperature thermal event. The homogenization temperature range of the ore-forming fluid in Cal3 is used to judge the cooling evolution trend of the ore-forming fluid. When the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenization temperature range of the ore-forming fluid in Cal3, it is determined that the ore-forming fluid has evolved from early high temperature to late low temperature cooling. Organic powder was extracted from the comparative sample; X-ray photoelectron spectroscopy was performed on the organic powder to obtain the aromatic carbon ratio, S / C atomic ratio and pyrrole nitrogen / pyridine nitrogen ratio of the organic matter, and to determine whether the organic matter alteration mechanism was caused by thermochemical sulfate reduction or thermal alteration. (7) Based on the results obtained in steps (1) to (6), establish a systematic analysis of the mineral formation sequence, ore-forming fluid evolution and organic matter participation mode, and obtain the organic matter participation fluid mineralization mode; There is no temporal order between steps (3) and (5); the micro-laser Raman spectroscopy test, X-ray photoelectron spectroscopy test in step (6), and steps (3) and (5) are not in temporal order.

2. The comprehensive discrimination method according to claim 1, characterized in that, In step (2), the polarization microscope observation includes observation of transmitted single-polarized light, cross-polarized light and reflected light; The results observed by the polarization microscope include mineral morphology, organic matter occurrence characteristics, and the interpenetration relationship between various minerals; the mineral morphology includes one or more of the following: disseminated, colloidal, and coarse-grained; the organic matter occurrence characteristics include optical structure, which includes one or more of the following: mosaic and homogeneous.

3. The comprehensive discrimination method according to claim 1, characterized in that, In step (2), the accelerating voltage of the cathode luminescence imaging is 5~10kV and the beam current is 0.5mA; The luminescent characteristics of the calcite include luminescence color and zoning features. Cal1 cathodoluminescence is bright yellow with uniform internal zoning and is replaced by Py1. Cal2 cathodoluminescence is dark orange to dark yellow with visible weak oscillating zoning. Py2, Sp2 and Cal2 coexist, indicating that Cal2, Py2 and Sp2 were formed at the same time. Cal3 cathodoluminescence is dark red with significant oscillating zoning. Cal3 coexists with Sp3, Gn3 and Py3.

4. The discrimination method according to claim 1, characterized in that, In step (3), the test conditions for laser ablation inductively coupled plasma mass spectrometry include: the laser ablation carrier gas is He, the compensation gas is Ar; the laser frequency is 8~10Hz, and the energy is 6~10J / cm. 2 The beam spot diameter is 44μm, and the signal is acquired for 100s at each point; The method for determining the mineral origin by the S / Se content ratio of pyrite and sphalerite includes: if the S / Se content ratio is <15000, the mineral is formed by magmatic sulfides; if the S / Se content ratio is 10000~28000, the mineral is formed by hydrothermal sulfides. The method for determining the evolution of mineralization temperature by the Zn / Cd content ratio of sphalerite includes: a higher Zn / Cd content ratio indicates a higher mineralization temperature; the Zn / Cd content ratio of Sp1 is 186, and the Zn / Cd content ratio of colloidal sphalerite Sp2 is 158, indicating a medium-high temperature environment; the Zn / Cd content ratio of Sp3 is 97, reflecting a systematic decrease in mineralization temperature; The method for determining the redox properties of a fluid by projecting the Fe-Mn-Mg triangular composition of calcite is as follows: the movement of data points toward the Fe-Mn endmembers indicates an increase in the oxidizing power of the fluid. The method for tracing the fluid source through the Y / Ho content ratio of calcite includes: a Y / Ho content ratio of 44 to 74 indicates that the fluid source is marine sediments; a Y / Ho content ratio of 26 to 28 indicates that the fluid source is terrigenous clastic material or volcanic ash; and when the Y / Ho content ratio is greater than 28 and less than 44, it indicates that the fluid source is a mixture of marine sediments and terrigenous clastic material or volcanic ash. The method of tracing the source of fluids also includes: determining the source of fluids by comparing the in-situ trace element content of Py1 and Py2. When the content of Mo, Mn, Zn and As in Py2 is higher than that in Py1, it is determined that the deep heat source fluids participated in the mineralization.

5. The comprehensive discrimination method according to claim 1, characterized in that, In step (4), the test conditions for the laser ablation multi-receiver inductively coupled plasma mass spectrometry include: using He as the carrier gas, Ar as the compensation gas, a laser frequency of 5 Hz, and an energy of 4 J / cm². 2 The beam spot diameter is 50 μm; The via δ 34 The specific steps for determining the sulfur source reaction mechanism by analyzing the changing trends of S at different mineralization stages include: when the δ of Py1 and Sp1 changes... 34 When the S values ​​are all < -10‰, the main sulfur source reaction mechanism is determined to be bacterial sulfate reduction; when the δ values ​​of Py3 and Sp3 are both < -10‰, the sulfur source reaction mechanism is determined to be bacterial sulfate reduction. 34 When the S value is 0 to +20‰ and the fluid inclusion temperature is >100℃, the sulfur source reaction mechanism is determined to be mainly thermochemical sulfate reduction; when δ 34 When an independent peak appears in the frequency histogram distribution of the S value within the range of -5 to 0‰, and the corresponding sulfide is spatially associated with an organic-rich layer, the sulfur source reaction mechanism is determined to be thermal desulfurization of organic matter.

6. The comprehensive discrimination method according to claim 1, characterized in that, In step (5), the conditions for measuring the homogenization temperature of the fluid inclusion include: a temperature range of -160 to 350°C, an ambient temperature of 20 to 25°C, and a relative humidity of 30 to 50%. The homogenization temperature range of the ore-forming fluid of Cal2 is 146.3~283.2℃, and the homogenization temperature range of the ore-forming fluid of Cal3 is 66.0~185.7℃. When the peak temperature of the homogenized temperature range of the ore-forming fluid in Cal2 is higher than the peak temperature of the homogenized temperature range of the ore-forming fluid in Cal3, the ore-forming fluid evolves from early high temperature to late low temperature cooling.

7. The comprehensive discrimination method according to claim 1, characterized in that, In step (6), the conditions for the microscopic laser Raman spectroscopy test include: a laser wavelength of 632.8 nm, an exposure time of 5–20 s, and a spectral range of 100–3000 cm⁻¹. -1 The spectral resolution is 0.6 cm⁻¹. -1 The spatial resolution was 400 nm, the ambient temperature was 22.3℃, and the humidity was 35%. The formula for calculating the highest paleotemperature is shown in Equation 1: T=737.3+320.9×R1-1067×R2-80.638×R1 2 Equation 1; Where R1 is the peak intensity ratio of peak D to peak G, and R2 is the peak area ratio of peak D to peak G; The asphalt includes intergranular asphalt filled with primary minerals, asphalt veinlets containing sulfides, and intergranular asphalt filled with hydrothermal vein minerals.

8. The comprehensive discrimination method according to claim 1, characterized in that, In step (6), the conditions for the X-ray photoelectron spectroscopy test include: the excitation source is an Al Kα target, the excitation energy is 1486.6 eV, and the vacuum degree is <5 × 10⁻⁶. -8 mbar; full spectrum scanning pass energy 100 eV, step size 1 eV; fine spectrum scanning pass energy 30 eV, step size 0.05 eV; spectral acquisition range 0~1350 eV, X-ray beam spot diameter 400 μm; C1s binding energy 284.8 eV as internal standard correction; The method for determining whether the organic matter alteration mechanism is caused by thermochemical sulfate reduction or thermal alteration includes: if the aromatic carbon atom ratio of asphalt is ≥75%, the S / C atomic ratio is 0.035~0.17, and the pyrrole nitrogen / pyridine nitrogen ratio is ≥3, then the organic matter alteration mechanism is caused by thermochemical sulfate reduction; if the aromatic carbon atom ratio of asphalt is <75%, the S / C atomic ratio is <0.035, and the pyrrole nitrogen / pyridine nitrogen ratio is <3, then the organic matter alteration mechanism is caused by thermal alteration.

9. The comprehensive discrimination method according to claim 1, characterized in that, In step (7), the organic matter's participation in the fluid mineralization process includes three stages: Early mineralization stage: The ore-forming fluids are injected to form ancient oil reservoirs, and after bacterial sulfate reduction, they form H2S-rich fluids, which precipitate to form Py1 and Cal1; the ore-forming fluids are low-temperature reducing hydrocarbon-rich fluids; Early mineralization stage: The mineralization fluid extracts metallic substances, and the warming of the ancient oil reservoir changes the mineralization mode of organic matter to thermochemical sulfate reduction and thermal desulfurization of organic matter, accompanied by Cal2 precipitation and the formation of Py2, Sp1, Sp2 and Gn1; the mineralization fluid is a high-temperature reducing basin brine fluid. Late mineralization stage: The mineralization fluid is formed by the infiltration and leaching of low-temperature oxidizing atmospheric precipitation. Oxidizing atmospheric precipitation infiltration and leaching, destruction of ancient oil reservoirs, and the consumption of residual thermochemical sulfate reduction or thermal desulfurization of organic matter to form H2S.

10. The discrimination method according to claim 9, characterized in that, The pre-mineralization stage: the temperature of the low-temperature reducing hydrocarbon-rich fluid is 77.56~148.22℃; In the early stage of mineralization, the temperature of the high-temperature reducing basin brine fluid is 146.3~283.2℃; The late-stage mineralization phase: the temperature of the mineralizing fluid formed by the infiltration and leaching of low-temperature oxidizing atmospheric precipitation is 66.0~185.7℃.

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