A method for judging the tungsten-tin mineralization potential of granite

Abstract

This invention discloses a method for determining the tungsten-tin mineralization potential of granite. This method performs whole-rock and mineralogy microanalysis on sampled granite to calculate three indicators: magma oxygen fugacity, magma differentiation, and magma-hydrothermal conversion intensity. These three indicators are used to efficiently evaluate the tungsten-tin mineralization potential of granite. This overcomes the difficulty in identifying tungsten-tin mineralization rock masses and establishes a new method and workflow for rapidly evaluating the tungsten-tin mineralization potential of granite in newly explored areas. This method has a greater than 70% probability of finding a tungsten-tin deposit, demonstrating its significant practical value.

Description

Technical Field

[0001] The invention belongs to the field of mineral exploration and evaluation, and particularly relates to a method for judging the tungsten-tin mineralization potential of granite. Background Art

[0002] Tungsten-tin, as irreplaceable, critical metal elements with significant applications and high supply security risks, is widely used in critical high-tech fields such as clean energy, information technology, aerospace, and national security. Tungsten-tin deposits occur in the inner and outer contact zones protruding from the top of granite. Once the mineralization rock body is identified, the relevant ore body can be quickly identified. However, China is one of the countries with the most widespread granite in the world, and only a very small number of these granites can form tungsten-tin deposits. Therefore, it is particularly important to develop a simple and effective method to identify the tungsten-tin mineralization potential of granite bodies.

[0003] Previous researchers used cassiterite, Ar-Ar dating and other methods to date the ores in tungsten-tin deposits to determine the formation age of the deposits. They then performed zircon U-Pb dating on the rock bodies in the mining area and determined whether they were mineralized rock bodies by comparing the spatiotemporal relationship between the rock bodies and the ore bodies. However, this method is only applicable to areas where deposits have been discovered and the ore minerals of the tungsten-tin deposits are cassiterite and Ar-Ar ages can be obtained. It cannot be widely used to determine the tungsten-tin mineralization potential of granite and cannot fully meet the current needs of mineral exploration.

[0004] Regarding the mineralization potential of granite and the identification of mineralized rock bodies, Li Huan et al. (2020) used characteristics such as U-Pb dating and Lu-Hf isotope ratios in granite bodies to determine the mineralization potential of granite. Many mineral deposits, such as W, Sn, Li, Be, U, Th, Fe, Cu, Pb, and Zn, may be associated with granite. Different types of granite can form different types of deposits. For example, copper deposits associated with granite are often associated with magmas with high oxygen fugacity. Therefore, simply using zircon U-Pb dating and Lu-Hf isotope ratios to identify granite mineralization can be ambiguous.

[0005] Therefore, it is necessary to find a new, efficient method suitable for all granites to determine the tungsten-tin mineralization potential, so as to reverse the shortage of tungsten-tin resources and achieve breakthroughs in mineral exploration. Summary of the Invention

[0006] In response to the problems of large uncertainty, multiple solutions, and lack of targeted mineral exploration in existing technologies, the present invention provides a method for determining the tungsten-tin mineralization potential of granite using whole-rock and mineral micro-area geochemistry. This method can quickly and accurately identify the tungsten-tin mineralization potential of granite, has a higher accuracy rate than traditional methods, and can significantly improve prospecting efficiency.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for determining the tungsten-tin mineralization potential of granite is provided, which specifically comprises the following steps:

[0009] (1) Delineation of mineralization areas: Collect geological, geophysical, and geochemical data based on the selected study area, conduct a comprehensive analysis of the mineralization prospects, and delineate favorable mineralization areas;

[0010] (2) Sample collection: Samples are collected from granites with mineralization potential in favorable mineralization areas, and at least 4-5 samples are collected from each promising granite;

[0011] (3) Sample analysis: Whole-rock major and trace element analysis of the samples was performed to obtain whole-rock major and trace element data, and zircon mineral microanalysis was performed to obtain zircon trace element data; the SiO2 content was determined, and the Fe2O3 / FeO, Rb / Sr, K / Rb, Nb / Ta, Zr / Hf, and TE1,3 differentiation coefficients were calculated using the whole-rock data of the granite; the U concentration (μg / g) was determined using the zircon trace element data, and the europium anomaly (Eu / Eu*), light rare earth (LREE), heavy rare earth (Total REE), granite formation temperature T (℃), and oxygen fugacity (lg(fO2)) parameters of the zircon were calculated;

[0012] (4) Identification of granite tungsten-tin mineralization potential:

[0013] The relationship between the SiO2 and Fe2O3 / FeO ratios in the whole granite rock and the relationship between temperature T and oxygen fugacity in the mineral zircon in the granite are used to determine the redox properties of the magma and distinguish the high and low oxygen fugacity. The Nb / Ta, Zr / Hf, TE1,3, Rb / Sr, and K / Rb parameters of the whole granite rock are then used to determine the degree of magma evolution and distinguish the degree of differentiation. Finally, the U concentration, Eu / Eu*, LREE, and Total REE of zircon are used to determine the degree of magma hydrothermal conversion and distinguish the intensity of magma-hydrothermal conversion. Based on the three indicators of granite's magma oxygen fugacity, magma differentiation degree, and magma-hydrothermal conversion intensity, it is judged whether the granite has the potential for tungsten and tin mineralization.

[0014] According to the above scheme, in step (4), the determination of granite tungsten-tin mineralization potential is specifically as follows:

[0015] ① Oxygen fugacity determination: Process the whole rock major and trace element data obtained in step 3). When SiO2 is between 66-75wt%, the Fe2O3 / FeO ratio falls within y=2.6198×10 -27 ×e 0.8503xBelow the curve (SiO2 as the abscissa and Fe2O3 / FeO as the ordinate), when 75wt% < SiO2 ≤ 80wt% and the Fe2O3 / FeO ratio is lower than 10, it indicates that these granites have the potential to form tungsten-tin deposits; for the trace element data of the zircon obtained in treatment step 3), when the temperature is between 600 - 900 °C and the oxygen fugacity (lg(fO2)) falls in the area below the curve of y = 0.0364x - 35.909 (lg(fO2) as the ordinate and temperature as the abscissa), it indicates that these granites have the potential for tungsten-tin mineralization. Meeting both of the above two indicators indicates that these granites have a low oxygen fugacity and the potential to form tungsten-tin deposits;

[0016] ② Discrimination of the degree of differentiation: For the whole-rock major and trace element data obtained in treatment step 3), if the parameters of the whole rock satisfy Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, K / Rb < 150, it indicates that these granites have a high degree of differentiation and the potential to form tungsten-tin deposits;

[0017] ③ Discrimination of the magma-hydrothermal transformation degree: For the trace element data of the zircon obtained in treatment step 3), if the zircon in these granites satisfies U > 250 μg / g, Eu / Eu* < 0.3, LREE > 20 μg / g, Total REE > 1050 μg / g, it indicates that these granites have experienced a strong magma-hydrothermal transformation process and the potential to form tungsten-tin deposits;

[0018] ④ If these granites meet the discrimination conditions of the above three aspects ①②③ at the same time, it indicates that these granites have the characteristics of low oxygen fugacity, high degree of differentiation, and high intensity of magma-hydrothermal conversion, and have good potential for tungsten-tin mineralization. It can be judged as a tungsten-tin ore-forming rock mass (the possibility of finding tungsten-tin > 70%), and then the prospecting target area is delineated within a certain radius according to the outcrop position of the granite; if the granite mass does not meet one of the above three indicators, it indicates that it is a non-ore-forming rock mass with little prospecting potential, and the target area is not delineated. Among them, the elements or compounds involved in steps (3) and (4) represent the mass percentage content of the corresponding elements or compounds. For example, SiO2 in step (4) represents its mass percentage content in the whole-rock major and trace elements. Unless otherwise marked, similar situations in the text are understood in the same way.

[0019] Preferably, when the granite mass meets the discrimination conditions of the above three aspects ①②③ at the same time and has the potential for tungsten-tin mineralization, it is judged as a tungsten-tin ore-forming rock mass, and the prospecting target area is delineated within a certain radius according to the outcrop position of the granite; if the granite mass does not meet one of the above three indicators, it indicates that it is a non-ore-forming rock mass with little prospecting potential, and the target area is not delineated.

[0020] According to the above scheme, in step 3), the TE1,3 differentiation coefficient is calculated as: TE1,3=[((2×Ce N / (La N +Pr N ))×(2×Pr N / (Ce N +Nd N ))×0.5)×((2×Tb N / Gd N +Dy N ))×(2×Dy N / (Tb N +Ho N ))×0.5](Irber,1999)}, where N represents the chondrite normalized value.

[0021] According to the above scheme, in step 3), the trace element data of zircon is used in combination with Geo-fO2 oxygen fugacity comprehensive analysis software and Geokit software to calculate the europium anomaly of zircon (Eu / Eu*=2×Eu N / (Sm N +Gd N )), light rare earth (LREE), heavy rare earth (Total REE), granite formation temperature T (℃) and oxygen fugacity (lg(fO2)) parameters.

[0022] According to the above scheme, in step 3),

[0023] Whole-rock major and trace element analysis: The granite samples were crushed to 200 mesh, and then the major elements were determined using X-ray fluorescence spectrometry (XRF) and potassium dichromate method to obtain the contents of SiO2, TiO2, Al2O3, FeO, Fe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5. The trace elements of the granite samples were then analyzed by ICP-MS to obtain the contents of Li, Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, and Ta.

[0024] Mineral micro-area analysis test: Part of the samples collected in step (2) are used to select zircons, and then the characteristics of the corresponding zircons are observed under a microscope and cathodoluminescence imaging, the types of zircons are recorded in detail, and laser ablation inductively coupled plasma mass spectrometry in situ micro-area element analysis is carried out to obtain trace element data for each test point.

[0025] According to the above solution, in step 4), the specific steps for obtaining the criteria for oxygen fugacity discrimination, differentiation degree discrimination, and magma-hydrothermal transformation degree discrimination are as follows:

[0026] Step 1. Take ore-forming rock masses and non-ore-forming rock masses, and collect more than 5 samples for each;

[0027] Step 2. Conduct whole-rock major and trace element analysis on the samples to obtain whole-rock major and trace element data, and conduct micro-area analysis of zircon minerals to obtain zircon trace element data; among them, calculate the Fe2O3 / FeO, Rb / Sr, K / Rb, Nb / Ta, Zr / Hf, TE1,3 differentiation coefficients using the whole-rock data of granite; use the zircon trace element data to calculate the europium anomaly (Eu / Eu*), light rare earth elements (LREE), heavy rare earth elements (Total REE), formation temperature T (°C) and oxygen fugacity (lg(fO2)) parameters of granite;

[0028] Step 3. Determine the criteria for oxygen fugacity discrimination, differentiation degree discrimination, and magma-hydrothermal transformation degree discrimination, where:

[0029] ① Oxygen fugacity discrimination: Process the data obtained in step 2, plot with the SiO2 content as the abscissa and the Fe2O3 / FeO ratio as the ordinate, and determine the following judgment criteria: When SiO2 is between 66-75 wt%, the Fe2O3 / FeO ratio falls below the position of the curve y = 2.6198×10 -27 ×e 0.8503x When 75 wt% < SiO2 ≤ 80 wt% and the Fe2O3 / FeO ratio is less than 10, it indicates that these granites may have the potential to form tungsten-tin deposits; plot with temperature T as the abscissa and oxygen fugacity (lg(fO2)) as the ordinate, and determine the following judgment criteria: When the temperature is between 600-900 °C and the oxygen fugacity (lg(fO2)) falls in the area below the curve y = 0.0364x - 35.909, it indicates that these granites may have the potential for tungsten-tin mineralization. Meeting both of the above two indicators indicates that these granites have a low oxygen fugacity and the potential to form tungsten-tin deposits;

[0030] ② Differentiation degree discrimination: Process the whole-rock major and trace element data obtained in step 2, plot with TE1,3 as the abscissa and Nb / Ta as the ordinate, plot with TE1,3 as the abscissa and Zr / Hf as the ordinate, plot with Zr / Hf as the abscissa and Nb / Ta as the ordinate, plot with K / Rb as the abscissa and Rb / Sr as the ordinate, and comprehensively obtain the following criteria: If the parameters of the whole rock meet Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, K / Rb < 150, it indicates that these granites have a high degree of differentiation and the potential to form tungsten-tin deposits;

[0031] ③ Determination of the degree of magma-hydrothermal conversion: The trace element data of the zircon obtained in step 2 were processed and mapped with Eu / Eu* as the horizontal coordinate and U as the vertical coordinate, Eu / Eu* as the horizontal coordinate and Hf as the vertical coordinate, Total REE as the horizontal coordinate and LREE as the vertical coordinate, and Total REE as the horizontal coordinate and Eu / Eu* as the vertical coordinate. The following standards were obtained: If the zircon in these granites meets U>250μg / g, Eu / Eu*<0.3, LREE>20μg / g, and TotalREE>1050μg / g, it means that these granites have experienced a strong magma-hydrothermal conversion process and have the potential to form tungsten-tin deposits.

[0032] The granitic magma that formed tungsten-tin minerals exhibits three characteristics: low oxygen fugacity, high degree of differentiation, and strong magma-to-hydrothermal conversion. Whole-rock geochemistry and trace element geochemistry of minerals (such as zircon) can well reflect these three characteristics. For example, the Fe2O3 / FeO ratio of whole rocks and the oxygen fugacity of zircon minerals in granite can determine the redox properties of the magma. The Nb / Ta, Zr / Hf, TE1,3, Rb / Sr, and K / Rb ratios of whole granite determine the degree of magma evolution. U, Eu / Eu*, LREE, and Total REE in zircon can reflect the degree of magma-hydrothermal conversion. Therefore, by distinguishing between ore-bearing and non-ore-bearing granites based on these three characteristics, it is possible to establish markers for the tungsten-tin mineralization potential of granites.

[0033] This method uses whole-rock and mineral micro-region geochemistry to determine the tungsten-tin mineralization potential of granite. First, the redox properties of the magma are determined using the whole-rock Fe2O3 / FeO ratio and the zircon (lg(fO2)) ratio within the granite. The Nb / Ta, Zr / Hf, TE1,3, Rb / Sr, and K / Rb parameters of the whole-rock granite are then used to determine the degree of magma evolution. Finally, the U, Eu / Eu*, LREE, and Total REE values of the zircon are used to determine the degree of hydrothermal conversion within the magma, ultimately determining whether the granite is a tungsten-tin mineralization body. This method closely integrates changes in whole-rock and mineral micro-region composition with the determination of the mineralization potential of tungsten-tin deposits, overcoming the inefficiency, long cycle times, and high costs associated with traditional methods for determining mineralization potential. This method has a greater than 70% probability of finding a tungsten-tin deposit, making it a highly promising method for determining the tungsten-tin mineralization potential of granite. This method proposes to use the whole-rock and mineral micro-area methods to determine the tungsten-tin mineralization potential of granite. It is an original innovative achievement that can provide a theoretical basis for further reducing the scale of prospecting targets in ore clusters and improve prospecting efficiency.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. The present invention provides a method for determining the tungsten-tin mineralization potential of granite using whole-rock and mineral micro-region geochemistry. By performing whole-rock and mineral micro-region analysis on the collected granite, three indicators, namely, magma oxygen fugacity, magma differentiation degree, and magma-hydrothermal conversion intensity, are calculated. Changes in whole-rock and mineral micro-region composition are closely linked to the determination of the mineralization potential of tungsten-tin deposits. These three indicators are used to efficiently evaluate the tungsten-tin mineralization potential of granite, overcoming the difficulty in determining tungsten-tin mineralized rock masses. This method and workflow for rapidly evaluating the tungsten-tin mineralization potential of granite in newly explored areas is established.

[0036] 2. The present invention is an economical, green and efficient new method for prospecting. Through the collection of a large amount of data, it is found that the possibility of finding tungsten-tin deposits through this method is greater than 70%, which has important practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 (a) The diagram of the main and trace Fe2O3 / FeO-SiO2 in the whole granite rock in Example 1; (b) The lg(fO2)-temperature diagram of zircon in the granite (data from tungsten-tin-bearing granites and non-tungsten-tin granites in South China and the Gangdese metallogenic belt).

[0038] Figure 2 These are the main and trace elements of the whole-rock granite in Example 1 (a) Nb / Ta-TE1,3 diagram, (b) Zr / Hf-TE1,3 diagram, (c) Nb / Ta-Zr / Hf diagram, and (d) Rb / Sr-K / Rb diagram (data from tin-bearing granites in South China and the Gangdise metallogenic belt).

[0039] Figure 3 (a) U-Eu / Eu* diagram, (b) Hf-Eu / Eu* diagram, (c) LREE-Total REE-Eu / Eu* diagram, and (d) Eu / Eu*-Total REE diagram of zircon in the granite in Example 1 (data collected from tungsten-tin-bearing and non-tungsten-tin granites in South China and the Gangdese metallogenic belt). DETAILED DESCRIPTION

[0040] The present invention is described in detail below with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are merely exemplary descriptions of the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable variations and combinations within the scope of the inventive concept of the present invention fall within the scope of protection of the present invention.

[0041] Example 1

[0042] A criterion for judging the tungsten-tin mineralization potential of granite is provided, comprising the following steps:

[0043] (1) Collect geological, geophysical, and geochemical data based on the selected study area, conduct a comprehensive analysis of the mineralization prospects, and identify favorable areas for mineralization in the South China and Gangdise metallogenic belts;

[0044] (2) Sample collection: Samples of mineralized and non-mineralized granites were collected in the favorable areas of South China and Gangdise metallogenic belts. A series of representative samples were collected for each promising granite.

[0045] (3) Whole-rock major and trace element analysis: The granite samples were crushed to 200 mesh, and then the major elements (SiO2, TiO2, Al2O3, FeO, Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5) were determined using X-ray fluorescence spectrometer (XRF) and potassium dichromate method. The sample processing process for XRF analysis is as follows: ① Place the 200 mesh sample in a 105℃ oven and dry it for 12 hours; ② Weigh ~1.0 g dried sample was placed in a constant weight ceramic crucible, burned in a muffle furnace at 1000℃ for 2 hours, taken out and cooled to room temperature before weighing to calculate the loss on ignition; ③ 6.0g flux (Li2B4O7:LiBO2:LiF=9:2:1), 0.6g sample, and 0.3g oxidant (NH4NO3) were weighed separately and placed in a platinum crucible, melted in a sample melting furnace at 1150℃ for 14 minutes, the crucible was taken out and transferred to refractory bricks for cooling, and then the glass piece was taken out for XRF testing. Then, inductively coupled plasma mass spectrometry (ICP-MS) was used to complete the trace element analysis of the granite samples (Li, Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta). The sample preparation for ICP-MS analysis was as follows: ① Place the 200-mesh sample in a 105°C oven to dry for 12 hours; ② Accurately weigh 50 mg of the powder sample and place it in a Teflon dissolving bomb; ③ Slowly add 1 ml of high-purity HNO3 and 1 ml of high-purity HF in sequence; ④ Place the Teflon dissolving bomb in a steel sleeve, tighten it, and place it in a 190°C oven to heat for more than 24 hours; ⑤ After the dissolving bomb cools down, open the lid and place it on a 140°C hot plate to evaporate to dryness, and then add 1 ml ⑥ Add 1 ml of high-purity HNO3, 1 ml of MQ water, and 1 ml of internal standard In (concentration of 1 ppm), place the Teflon bomb in the steel sleeve again, tighten it, and heat it in a 190°C oven for more than 12 hours; ⑦ Transfer the solution to a polyethylene bottle and dilute it to 100 g with 2% HNO3 for ICP-MS analysis.

[0046] (4) Mineral microanalysis test: Part of the samples collected in step (2) were used to select zircons, and then the characteristics of the corresponding zircons were observed under a microscope and cathode luminescence images, and the types of zircons were recorded in detail. In addition, in-situ micro-area element analysis was carried out by laser ablation inductively coupled plasma mass spectrometry. The GeolasPro laser ablation system was composed of a COMPexPro 102ArF193nm excimer laser and a MicroLas optical system, and the ICP-MS model was Agilent 7700e. During the laser ablation process, helium was used as the carrier gas and argon as the compensation gas to adjust the sensitivity. The two were mixed through a T-type connector before entering the ICP. The laser ablation system was equipped with a signal smoothing device (Hu et al., 2015). The laser beam spot and frequency were 32 or 44μm and 5Hz, respectively. The trace element data of each test point was then completed using the software ICPMSDataCal.

[0047] (5) Calculation of various parameters of granite formation: Using the whole rock data of granite, calculate the Rb / Sr, K / Rb, Nb / Ta, Zr / Hf, TE1,3 differentiation coefficient {where TE1,3=[((2×Ce N / (La N +Pr N ))×(2×Pr N / (Ce N +Nd N ))×0.5)×((2×Tb N / Gd N +Dy N ))×(2×Dy N / (Tb N +Ho N ))×0.5] (Irber, 1999), where N represents the chondrite-normalized value. Zircon trace element data, combined with Geo-fO2 oxygen fugacity analysis software and Geokit software, were used to calculate parameters such as the europium anomaly (Eu / Eu*), light rare earth elements (LREEs), heavy rare earth elements (Total REEs), granite formation temperature (T (°C), and oxygen fugacity (lg(fO2)).

[0048] (6) Determine the criteria for determining oxygen fugacity, differentiation degree, and magma-hydrothermal conversion degree, including:

[0049] ① Oxygen fugacity determination: Process the data obtained in step 5 and project it with SiO2 content as the horizontal axis and Fe2O3 / FeO ratio as the vertical axis, as shown in the following figure: Figure 1 a. Determine the following criteria: When SiO2 is between 66-75wt%, the Fe2O3 / FeO ratio falls within y=2.6198×10 -27 ×e0.8503x Below the curve, when 75 wt% < SiO2 ≤ 80 wt% and the Fe2O3 / FeO ratio is less than 10, it indicates that these granites may have the potential to form tungsten-tin deposits; plotting with temperature T as the abscissa and oxygen fugacity (lg(fO2)) as the ordinate, as Figure 1 Figure b, the following judgment criteria are determined: when the temperature is between 600 - 900 °C and the oxygen fugacity (lg(fO2)) falls in the area below the curve of y = 0.0364x - 35.909 (lg(fO2) as the ordinate and temperature as the abscissa), it indicates that these granites may have the potential for tungsten-tin mineralization. Meeting both of the above two indicators indicates that these granites have a low oxygen fugacity and the potential to form tungsten-tin deposits;

[0050] ② Discrimination of differentiation degree: Processing the whole-rock major and trace element data obtained in step 5, plotting with TE1,3 as the abscissa and Nb / Ta as the ordinate (as Figure 2 Figure a), plotting with TE1,3 as the abscissa and Zr / Hf as the ordinate (as Figure 2 Figure b), plotting with Zr / Hf as the abscissa and Nb / Ta as the ordinate (as Figure 2 Figure c), plotting with K / Rb as the abscissa and Rb / Sr as the ordinate (as Figure 2 Figure d), and comprehensively obtaining the following criteria: If the parameters of the whole rock satisfy Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, and K / Rb < 150, it indicates that these granites have a high degree of differentiation and the potential to form tungsten-tin deposits;

[0051] ③ Discrimination of magma-hydrothermal transformation degree: Processing the trace element data of zircon obtained in step 5, plotting with Eu / Eu* as the abscissa and U as the ordinate (as Figure 3 Figure a), plotting with Eu / Eu* as the abscissa and Hf as the ordinate (as Figure 3 Figure b), plotting with Total REE as the abscissa and LREE as the ordinate (as Figure 3 Figure c), plotting with Total REE as the abscissa and Eu / Eu* as the ordinate (as Figure 3 Figure d), and comprehensively obtaining the following criteria: If the zircon in these granites satisfies U > 250 μg / g, Eu / Eu* < 0.3, LREE > 20 μg / g, and Total REE > 1050 μg / g, it indicates that these granites have experienced a strong magma-hydrothermal transformation process and have the potential to form tungsten-tin deposits.

[0052] If these granites simultaneously meet the above-mentioned discriminant conditions ①, ②, and ③, it indicates that these granites have the characteristics of low oxygen fugacity, high degree of differentiation, and high intensity of magma-hydrothermal conversion, and have good tungsten and tin metallogenic potential. They can be judged as tungsten and tin metallogenic rock bodies, and then prospecting target areas are delineated within a certain radius according to the outcrop position of the granites; if the granite body does not meet one of the above three indicators, it indicates that it is a non-metallogenic rock body with little prospecting potential, and no target area delineation is carried out.

[0053] Example 2 Discrimination of the Metallogenic Potential of W-Sn Granites in the South China Metallogenic Belt

[0054] (1) Based on the selected study area, collect geological, geophysical, geochemical and other data, and comprehensively analyze the metallogenic prospect, and delineate the favorable areas for mineralization in the South China Metallogenic Belt;

[0055] (2) Sample collection: Collect samples of granites with metallogenic potential in the favorable areas for mineralization in the South China Metallogenic Belt, and collect a series of representative samples from each prospective granite;

[0056] (3) Refer to steps (3)-(5) in Example 1 for data analysis and calculation;

[0057] (4) According to step (6) in Example 1, the oxygen fugacity, degree of differentiation, and magma-hydrothermal conversion degree of the Xihuashan samples collected in South China were discriminated to查明 whether they have metallogenic potential. Among them:

[0058] ① Oxygen fugacity discrimination: The SiO2 of the South China granites is between 71-79 wt%, and the Fe2O3 / FeO ratio is between 0.03-11. Most of the samples fall within the shaded area (when SiO2 is between 66-75 wt%, the Fe2O3 / FeO ratio falls below the position of the curve y = 2.6198×10 -27 ×e 0.8503x ; when 75 wt% < SiO2 ≤ 80 wt%, the Fe2O3 / FeO ratio is lower than 10), as Figure 1 a, and when the data of temperature (550°-900°) and oxygen fugacity (lg(fO2)) (-24--3) are input into Figure 1 b, and fall in the area below the curve y = 0.0364x - 35.909, it indicates that these granites may have tungsten and tin metallogenic potential, indicating that the oxygen fugacity in the South China region meets the metallogenic conditions.

[0059] ② Degree of differentiation discrimination: The ratios obtained from the whole-rock data of the South China granites are Rb / Sr (3.1-420), K / Rb (45-140), Nb / Ta (0.5-7.5), Zr / Hf (5.1-34.5), TE1,3 differentiation coefficient (0.95-1.26) ( Figure 2) For most samples, the parameters satisfy Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, and K / Rb < 150, indicating that these granites have a high degree of differentiation and the potential to form tungsten-tin deposits.

[0060] ③ Discrimination of magma-hydrothermal transformation degree: The U of granites in South China ranges from 200 to 40000 μg / g, Eu / Eu* ranges from 0 to 0.37, LREE ranges from 9.00 to 10000 μg / g, and Total REE ranges from 500 to 26000 μg / g ( Figure 3 ) There is a characteristic of magma zircon turning into hydrothermal zircon, and it satisfies U > 250 μg / g, Eu / Eu* < 0.3, LREE > 20 μg / g, and Total REE > 1,050 μg / g, indicating that these granites have experienced a strong magma-hydrothermal transformation process and have the potential to form tungsten-tin deposits. In summary, these granites meet the conditions for tungsten-tin mineralization in terms of oxygen fugacity, differentiation degree, and magma-hydrothermal transformation degree. After later verification, the Xihuashan tungsten-tin deposit was also discovered in this area.

[0061] Example 3 Discrimination of the metallogenic potential of W-Sn granites in Hahai'gang and Jagang in the Gangdese metallogenic belt

[0062] (1) Collect geological, geophysical, geochemical and other data based on the selected study area, and comprehensively analyze the metallogenic prospect to delineate the favorable ore-forming areas in the Gangdese metallogenic belt;

[0063] (2) Sample collection: Collect samples of prospective Hahai'gang and Jagang W-Sn granites in the favorable ore-forming areas of the Gangdese metallogenic belt, and collect a series of representative samples from each prospective granite;

[0064] (3) Refer to steps (3)-(5) in Example 1 for data analysis and calculation;

[0065] (4) According to step (6) in Example 1, the oxygen fugacity, differentiation degree, and magma-hydrothermal transformation degree of the samples collected from Hahai'gang and Jagang in the Gangdese metallogenic belt were discriminated to查明其是否具有成矿潜力。其中:

[0066] ① Oxygen fugacity discrimination: The SiO2 of the granites in this area ranges from 70.5 to 78 wt%, and the Fe2O3 / FeO ratio ranges from 0.05 to 2.00. Most samples fall within the shaded area (when SiO2 ranges from 66 to 75 wt%, the Fe2O3 / FeO ratio falls below the position of the curve y = 2.6198×10 -27 ×e 0.8503x When 75 wt% < SiO2 ≤ 80 wt%, the Fe2O3 / FeO ratio is below 10 ( Figure 1 a), and the data of temperature (550°-800°) and oxygen fugacity (lg(fO2))(-25--12) are put into Figure 1 In b, when these data fall below the curve y = 0.0364x-35.909, it indicates that these granites may have tungsten-tin mineralization potential.

[0067] ② Differentiation degree: The ratios calculated from the whole rock data of these granites are Rb / Sr (0.9-90), K / Rb (30-225), Nb / Ta (0.2-5.1), Zr / Hf (5-30), TE1,3 differentiation coefficient (0.97-1.48) ( Figure 2 ), most of the samples satisfy the parameters of Nb / Ta<7, Zr / Hf<35, TE1,3>1.05, Rb / Sr>2, K / Rb<150, indicating that these granites have a high degree of differentiation and have the potential to form tungsten-tin deposits.

[0068] ③ Identification of the degree of magma-hydrothermal conversion: The U of these granites is between 800-15000μg / g, Eu / Eu* is between 0-0.31, LREE is between 15-300μg / g, and Total REE is between 800-8200μg / g ( Figure 3 ), there are characteristics of magmatic zircon converted into hydrothermal zircon, and meet U>250μg / g, Eu / Eu*<0.3, LREE>20μg / g, Total REE>1050μg / g, indicating that these granites have undergone a strong magma-hydrothermal conversion process and have the potential to form tungsten-tin deposits; in summary, these granites meet the conditions for tungsten-tin mineralization in terms of oxygen fugacity, degree of differentiation and degree of magma-hydrothermal conversion. After subsequent verification, the Hahaigang and Jiagang tungsten deposits were also found in this area.

[0069] Example 4: Determination of W-Sn Mineralization Potential of Bangbule and Chagele Granites in the Gangdise Metallogenic Belt

[0070] (1) Collect geological, geophysical, and geochemical data based on the selected study area, conduct a comprehensive analysis of the mineralization prospects, and identify favorable areas for mineralization in the Gangdise metallogenic belt;

[0071] (2) Sample collection: W-Sn samples were collected from the Bangbule and Chagele granites with mineralization potential in the favorable areas of the Gangdise metallogenic belt. A series of representative samples were collected from each promising granite.

[0072] (3) Perform data analysis and calculations according to steps (3) to (5) in Example 1;

[0073] (4) According to step (6) in Example 1, the oxygen fugacity, degree of differentiation, and magma-hydrothermal transformation degree of Bangbule and Chagele in the Gangdese metallogenic belt were discriminated to查明其是否具有成矿潜力。其中:

[0074] ① Oxygen fugacity discrimination: The SiO2 of the granite in this area is between 72.5 - 78 wt%, and the Fe2O3 / FeO ratio is between 0.02 - 7.00. Most of the samples fall within the shaded area (when SiO2 is between 66 - 75 wt% and the Fe2O3 / FeO ratio falls below the curve of y = 2.6198×10 -27 ×e 0.8503x ; when 75 wt% < SiO2 ≤ 80 wt% and the Fe2O3 / FeO ratio is less than 1)( Figure 1 a), and the data of temperature (570° - 850°) and oxygen fugacity (lg(fO2)) (-22 - -2.5) are input into Figure 1 b. These data fall within the area below the curve of y = 0.0364x - 35.909, indicating that these granites may have the potential for tungsten-tin mineralization.

[0075] ② Degree of differentiation discrimination: The ratios calculated from the whole-rock data of the granite in Bangbule and Chagele are Rb / Sr (0.18 - 4.0), K / Rb (110 - 250), Nb / Ta (6.0 - 19), Zr / Hf (20 - 44), and TE1,3 differentiation coefficient (0.97 - 1.05)( Figure 2 ). These samples basically do not meet the conditions of Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, and K / Rb < 150, indicating that these granites have a low degree of differentiation and no potential to form tungsten-tin deposits.

[0076] ③ Magma-hydrothermal transformation degree discrimination: The U of these granites is between 60 - 360 μg / g, the Eu / Eu* is between 0.25 - 0.51, the LREE is between 30 - 90 μg / g, and the Total REE is between 600 - 1050 μg / g( Figure 3 ). There is no obvious characteristic of the transformation from magmatic zircon to hydrothermal zircon, and it does not meet the conditions of U > 250 μg / g, Eu / Eu* < 0.3, LREE > 20 μg / g, and Total REE > 1050 μg / g, indicating that these granites have not experienced the magma-hydrothermal transformation process and have no potential to form tungsten-tin deposits; In summary, although the oxygen fugacity of these Bangbule and Chagele granites is relatively low, they do not meet the conditions for tungsten-tin mineralization in terms of the degree of differentiation and magma-hydrothermal transformation degree, and do not have the potential to form tungsten-tin deposits. After later verification, no tungsten-tin deposits have been found in these areas.

[0077] It should be noted that the part "查明其是否具有成矿潜力" in the original text seems to be an incomplete expression in Chinese. The translation here tries to make the whole text fluent while waiting for a more accurate expression in the original text for a more precise translation.In summary, the oxygen fugacity, degree of differentiation and degree of magma-hydrothermal conversion of granites in Gangdise and South China's Xihuashan, Hahaigang, Jiagang, Bangbule and Chagel areas were judged, and it was concluded that Xihuashan, Hahaigang and Jiagang areas have the potential to form tungsten-tin deposits, while Bangbule and Chagel areas do not have the potential for tungsten-tin deposits due to insufficient degree of differentiation and magma-hydrothermal conversion. Through the drilling verification work of the geological team in the later period, tungsten-tin deposits were found in Xihuashan, Hahaigang and Jiagang areas, while the drilling verification work in Bangbule and Chagel areas only found lead-zinc ore bodies, and no tungsten-tin ore bodies were found, thereby verifying the judgment of the method of the present invention, indicating that the method is a method for judging the tungsten-tin mineralization potential of granite that is very worthy of promotion.

Claims

1. A method for determining the tungsten-tin mineralization potential of granite, characterized in that: The specific steps include: (1) Delineation of mineralization areas; (2) Collect samples; (3) Sample analysis: Whole-rock major and trace element analysis of the samples was performed to obtain whole-rock major and trace element data, and zircon mineral microanalysis was performed to obtain zircon trace element data; the SiO2 content was determined, and the Fe2O3 / FeO, Rb / Sr, K / Rb, Nb / Ta, Zr / Hf, and TE1,3 differentiation coefficients were calculated using the whole-rock data of granite; Using zircon trace element data, we determined the U concentration and calculated the zircon europium anomaly, light rare earth elements, heavy rare earth elements, granite formation temperature T, and oxygen fugacity parameters. (4) Identification of granite tungsten-tin mineralization potential: The relationship between SiO2 and Fe2O3 / FeO ratios in granite and the relationship between temperature T and oxygen fugacity in the mineral zircon in granite are used to determine the redox properties of magma and to discriminate between high and low oxygen fugacity. Then, the Nb / Ta, Zr / Hf, TE1,3, Rb / Sr, and K / Rb parameters of the granite whole rock are used to determine the degree of magma evolution and the degree of differentiation. Finally, the U concentration, europium anomaly, light rare earth, and heavy rare earth of zircon are used to determine the degree of magma-hydrothermal conversion and the intensity of magma-hydrothermal conversion. Based on the three indicators of granite magma oxygen fugacity, magma differentiation degree, and magma-hydrothermal conversion intensity, it is determined whether the granite has tungsten-tin mineralization potential. The specific judgment method is as follows: ① Oxygen fugacity discrimination: For the whole-rock major and trace element data obtained in treatment step (3), when SiO2 is between 66-75 wt%, and the Fe2O3 / FeO ratio falls below the position of the curve y = 2.6198×10 -27 ×e 0.8503x ; when 75 wt% < SiO2 ≤ 80 wt% and the Fe2O3 / FeO ratio is less than 10; for the trace element data of zircon obtained in treatment step (3), when the temperature T is between 600-900 °C and the oxygen fugacity falls below the region of the curve y = 0.0364x - 35.

909. When both of the above two indicators are satisfied, it indicates that these granites have low oxygen fugacity; ② Determination of differentiation degree: Process the whole-rock major and trace element data obtained in step (3). If the whole-rock parameters meet Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, and K / Rb < 150, it indicates that these granites have a high degree of differentiation. ③ Determination of the degree of magma-hydrothermal conversion: Process the trace element data of zircons obtained in step (3). If the zircons in these granites meet the conditions of U>250μg / g, Eu / Eu*<0.3, LREE>20μg / g, and Total REE>1050μg / g, it indicates that these granites have experienced a strong magma-hydrothermal conversion process. ④ If these granites meet the above three criteria ①②③ at the same time, it means that these granites have the characteristics of low oxygen fugacity, high degree of differentiation, and strong magma-hydrothermal conversion intensity, and have granite tungsten-tin mineralization potential.

2. The method according to claim 1, characterized in that When a granite body meets the three criteria of ①②③ at the same time, it has the potential to form tungsten-tin mineralization and is judged to be a tungsten-tin mineralization rock body. The prospecting target area is delineated within a certain radius according to the outcrop position of the granite. If the granite body does not meet any of the three criteria above, it is a non-mineralization rock body with low prospecting potential, and no target area is delineated.

3. The method according to claim 1, characterized in that In step (3), the trace element data of zircon is used in combination with Geo-fO2 oxygen fugacity comprehensive analysis software and Geokit software to calculate the europium anomaly, light rare earth, heavy rare earth, granite formation temperature T and oxygen fugacity parameters of zircon.

4. The method according to claim 1, wherein In the step (3), Whole-rock major and trace element analysis: The granite samples were crushed to 200 mesh, and then the major elements were determined using X-ray fluorescence spectrometry and potassium dichromate method to obtain the contents of SiO2, TiO2, Al2O3, FeO, Fe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5. The trace elements of the granite samples were then analyzed using ICP-MS to obtain the contents of Li, Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Sn, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, and Ta. Mineral micro-area analysis test: Part of the samples collected in step (2) are used to select zircons, and then the characteristics of the corresponding zircons are observed under a microscope and cathodoluminescence imaging, the types of zircons are recorded in detail, and laser ablation inductively coupled plasma mass spectrometry in situ micro-area element analysis is carried out to obtain trace element data for each test point.

5. The method according to claim 1, wherein In step (4), the specific steps for obtaining the standards for oxygen fugacity discrimination, differentiation degree discrimination, and magma-hydrothermal conversion degree discrimination are as follows: Step 1. Take ore-forming rock mass and non-ore-forming rock mass, and collect more than 5 samples from each; Step 2. Perform a whole-rock major and trace element analysis on the sample to obtain whole-rock major and trace element data, and perform a micro-area analysis of zircon minerals to obtain zircon trace element data; the whole-rock data of the granite are used to calculate the Fe2O3 / FeO, Rb / Sr, K / Rb, Nb / Ta, Zr / Hf, and TE1,3 differentiation coefficients; Using zircon trace element data, calculate zircon europium anomaly, light rare earth, heavy rare earth, granite formation temperature T and oxygen fugacity parameters; Step 3. Determine the criteria for determining oxygen fugacity, differentiation degree, and magma-hydrothermal conversion degree, where: ① Oxygen fugacity discrimination: Process the data obtained in Step 2. Plot with the SiO2 content as the abscissa and the Fe2O3 / FeO ratio as the ordinate to determine the following judgment criteria: When SiO2 is between 66 - 75 wt%, and the Fe2O3 / FeO ratio falls below the position of the curve y = 2.6198×10 -27 ×e 0.8503x When the temperature is between 600 - 900 °C and the oxygen fugacity falls below the area of the curve y = 0.0364x - 35.909; When both of the above two indicators are met, it indicates that these granites have a low oxygen fugacity and the potential to form tungsten-tin deposits; ② Determination of differentiation degree: Process the whole-rock major and trace element data obtained in step 2 and map them with TE1,3 as the horizontal coordinate and Nb / Ta as the vertical coordinate, TE1,3 as the horizontal coordinate and Zr / Hf as the vertical coordinate, Zr / Hf as the horizontal coordinate and Nb / Ta as the vertical coordinate, and K / Rb as the horizontal coordinate and Rb / Sr as the vertical coordinate. The following criteria are obtained by comprehensive analysis: If the whole-rock parameters meet Nb / Ta < 7, Zr / Hf < 35, TE1,3 > 1.05, Rb / Sr > 2, and K / Rb < 150, it indicates that these granites have a high degree of differentiation and have the potential to form tungsten-tin deposits; ③ Determination of the degree of magma-hydrothermal conversion: The trace element data of the zircon obtained in step 2 were processed and mapped with Eu / Eu* as the horizontal coordinate and U as the vertical coordinate, Eu / Eu* as the horizontal coordinate and Hf as the vertical coordinate, Total REE as the horizontal coordinate and LREE as the vertical coordinate, and Total REE as the horizontal coordinate and Eu / Eu* as the vertical coordinate. The following standards were obtained: If the zircon in these granites meets U>250μg / g, Eu / Eu*<0.3, LREE>20μg / g, and Total REE>1050μg / g, it means that these granites have experienced a strong magma-hydrothermal conversion process and have the potential to form tungsten-tin deposits.

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