A method for determining the direction of fluid migration in a hydrothermal deposit

Abstract

The application discloses a method suitable for judging fluid migration direction of hydrothermal deposit, selects hydrothermal deposits with correlation in a study area; collects hydrothermal mineral samples from each hydrothermal deposit, determines and marks corresponding metallogenic stages of each hydrothermal deposit, divides the hydrothermal deposit into pre-mineralization stage, mineralization stage and post-mineralization stage based on the metallogenic stages; respectively tests stable isotopes of the hydrothermal mineral samples in the pre-mineralization stage, the mineralization stage and the post-mineralization stage, judges mineral stable isotope variation rules corresponding to the hydrothermal mineral samples in different mineralization stages; compares and studies the mineral stable isotope variation rules of the hydrothermal mineral samples in each mineralization stage of two or more hydrothermal deposits, regards a direction in which the mineral stable isotope variation rules of the hydrothermal deposits tend to be consistent as a fluid migration direction; selects another isotope for verification; the application regards the stable isotope variation rule as an effective means for tracing the source of the hydrothermal fluid of the deposit.

Description

Technical Field

[0001] This invention relates to the field of mineral deposit fluid transport technology, and specifically to a method for determining the direction of fluid transport in hydrothermal deposits. Background Technology

[0002] The formation of hydrothermal deposits is inseparable from the participation of ore-forming fluids, and fluid inclusions, as direct records of magmatic hydrothermal fluid activity trapped in mineral lattices, have long been recognized and utilized by geologists. Since the introduction of fluid inclusion research into my country's geosciences in the 1960s, the depth and level of research in mineral deposit geology and other fields have been continuously improved with the continuous advancement and enrichment of research methods. The study of fluid inclusions can provide accurate information on the physicochemical properties of ore-forming fluids, such as temperature, salinity, composition, pressure, density, pH, and Eh. Therefore, it is one of the most important means and methods for studying the properties, temporal-spatial evolution characteristics, diagenetic and mineralization depths, and mineralization mechanisms of ore-forming fluids in hydrothermal mineralization systems.

[0003] Currently, most methods for determining the direction of fluid migration in hydrothermal deposits rely on accurate information about the physicochemical properties of the ore-forming fluid, such as temperature, salinity, composition, pressure, density, pH, and Eh. The numerous factors involved make the determination process complex. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the direction of fluid migration in hydrothermal deposits, in order to solve the technical problem that most existing methods for determining the direction of fluid migration rely on accurate information about the physicochemical properties of the ore-forming fluid, such as temperature, salinity, composition, pressure, density, pH, and Eh, which involves a large number of factors and leads to a complex determination process.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0006] A method for determining the direction of fluid migration in hydrothermal deposits includes the following steps:

[0007] Step 100: Select an area with the same mineralization background and the same hydrothermal system as the study area, and select two or more hydrothermal deposits with a relationship within the study area;

[0008] Step 200: Collect hydrothermal mineral samples from each of the hydrothermal deposits, analyze the hydrothermal mineral samples respectively, determine and mark the mineralization period corresponding to each hydrothermal mineral sample, and determine the mineral formation sequence corresponding to the ore minerals in the hydrothermal deposit based on the mineralization period of each hydrothermal mineral sample and the spatial relative position of each hydrothermal mineral sample in the hydrothermal deposit.

[0009] Step 300: Conduct stable isotope tests on hydrothermal mineral samples before mineralization, during mineralization, and after mineralization to determine the variation patterns of stable isotopes of minerals in different mineralization stages before mineralization, during mineralization, and after mineralization.

[0010] Step 400: Compare and study the mineral stable isotope variation patterns of hydrothermal mineral samples in two or more selected hydrothermal deposits, take the direction in which the mineral stable isotope variation patterns in the hydrothermal deposit tend to be consistent as the fluid migration direction, and take the opposite direction of the fluid migration direction as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0011] Step 500: Verify the variation law of mineral stable isotopes in different mineralization stages obtained in step 300 and the fluid migration direction obtained in step 400 by the variation direction of sulfur isotope content in the hydrothermal mineral sample in the hydrothermal deposit.

[0012] As a preferred embodiment of the present invention, the method for selecting areas with the same mineralization background and the same hydrothermal system as the study area in step 100 is as follows:

[0013] Based on regional geological survey data and geophysical and geochemical data, study areas with the same metallogenic background were selected, and geochemical exploration was carried out in the study areas to determine that the selected study areas are located in the same tectonic-hydrothermal background.

[0014] Use hydrothermal alteration characteristics or deposit type to determine whether the hydrothermal deposits in the selected study area belong to the same hydrothermal system, and select two or more hydrothermal deposits that belong to the same hydrothermal system.

[0015] As a preferred embodiment of the present invention, the method of selecting two or more hydrothermal deposits in the same hydrothermal system is as follows: selecting two or more hydrothermal deposits that are spatially related from the study area;

[0016] The selection space includes vertical space and / or horizontal space;

[0017] Two or more hydrothermal deposits that are related refer to hydrothermal deposits that have the same geochemical anomaly and are located in the same tectonic region.

[0018] In a preferred embodiment of the present invention, in step 200, a mineral deposit study is conducted on two or more selected hydrothermal deposits, hydrothermal mineral samples are collected from the hydrothermal deposits, and based on the macroscopic and microscopic characteristics of the ore minerals in the hydrothermal deposits, the hydrothermal mineral samples in the hydrothermal deposits are respectively classified into hydrothermal minerals at different mineralization stages: pre-mineralization, mineralization period, and post-mineralization. The specific implementation method is as follows:

[0019] Multiple hydrothermal mineral samples were collected from the hydrothermal deposit, and all hydrothermal mineral samples were ground into thin sections.

[0020] Thin sections of all hydrothermal mineral samples were examined under a transmitted light and reflected light microscope to identify the mineralization sequence of the hydrothermal mineral samples at different mineralization stages and to determine the current mineralization stage of the hydrothermal mineral samples.

[0021] The specific location of the collected hydrothermal mineral samples in the hydrothermal deposit, as well as the corresponding mineralization stage, are marked.

[0022] As a preferred embodiment of the present invention, in step 300, stable isotope testing is performed on hydrothermal mineral samples collected in each of the hydrothermal deposits, or stable isotope testing is performed on single minerals in each of the hydrothermal deposits, to determine the stable isotope characteristics formed in different mineralization stages in each of the hydrothermal deposits.

[0023] The stable isotope test results are marked on the sampling location of the hydrothermal deposit to determine the variation characteristics of the hydrothermal mineral samples corresponding to different mineralization stages before mineralization, during mineralization, and after mineralization.

[0024] As a preferred embodiment of the present invention, the method for performing stable isotope testing on hydrothermal mineral samples collected from each of the hydrothermal deposits is as follows:

[0025] A stable gas isotope mass spectrometer was used to detect the hydrogen and oxygen isotopes in each hydrothermal mineral sample, and the detection results of the hydrogen and oxygen isotopes were marked on the spatial relative position of the hydrothermal mineral sample in the hydrothermal deposit.

[0026] Based on the range of hydrogen and oxygen isotope content corresponding to different spatial relative positions of hydrogen and oxygen isotopes in the same hydrothermal deposit, the changes in the hydrothermal process of the same hydrothermal deposit are determined based on the variation law of the range of hydrogen and oxygen isotope content.

[0027] Based on the range of hydrogen and oxygen isotope contents corresponding to the same mineralization stage in two or more selected hydrothermal deposits, the direction of fluid migration corresponding to the same mineralization stage in different hydrothermal deposits is determined based on the variation law of the range of hydrogen and oxygen isotope contents.

[0028] As a preferred embodiment of the present invention, the hydrogen and oxygen isotope variation patterns of hydrothermal mineral samples corresponding to the same mineralization stage in two or more hydrothermal deposits are compared, and the direction in which the hydrogen and oxygen isotope variation patterns tend to be consistent is taken as the fluid migration direction, and the opposite direction of the fluid migration direction is taken as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0029] As a preferred embodiment of the present invention, in step 500, the method for verifying the variation law of mineral stable isotopes in different mineralization stages obtained in step 300 by the variation direction of sulfur isotope content in the hydrothermal mineral sample in the hydrothermal deposit is as follows:

[0030] When collecting hydrothermal mineral samples from the hydrothermal deposit, the collection work is calibrated on a regional scale profile, and the spatial relative position corresponding to each sampling work is determined.

[0031] Identify the mineralization stage corresponding to the collected hydrothermal mineral samples;

[0032] The collected hydrothermal mineral samples were subjected to laser etching and sulfur isotope testing.

[0033] Determine the sulfur isotope variation patterns of hydrothermal mineral samples from different mineralization stages.

[0034] As a preferred embodiment of the present invention, in step 500, the method for verifying the fluid migration direction obtained in step 400 by the change direction of sulfur isotope content in the hydrothermal mineral sample within the hydrothermal deposit is as follows:

[0035] Hydrothermal mineral samples were collected from two or more of the aforementioned hydrothermal deposits, and the mineralization stage corresponding to each hydrothermal mineral sample was determined.

[0036] The collected hydrothermal mineral samples were subjected to laser etching and sulfur isotope testing.

[0037] Determine the sulfur isotope variation patterns of two or more hydrothermal deposits at each mineralization stage, take the direction in which the sulfur isotope variation patterns tend to be consistent as the fluid migration direction, and take the opposite direction of the fluid migration direction as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] This invention uses the variation patterns of stable isotopes as an effective means of tracing the origin of hydrothermal fluids in mineral deposits, and by using two or more stable isotopes to cross-reference each other, it may be able to effectively indicate the migration path or direction of fluids in regional mineral deposits. Attached Figure Description

[0040] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0041] Figure 1 This is a flowchart of the method for determining the migration direction of ore-forming hydrothermal fluids provided in Embodiment 1 of the present invention;

[0042] Figure 2 This is a flowchart illustrating the specific process for determining the migration direction of ore-forming hydrothermal fluids, as provided in Embodiment 1 of the present invention.

[0043] Figure 3 A typical mineral deposit was selected from the area: the mineral circumferential structure of the Xiaohe gold mine and the mineral formation sequence of its formation.

[0044] Figure 4 The study examines the variation range and spatial distribution characteristics of H isotopes in typical mineral deposits within the region: Xiaohe Gold Mine, Wangzhuang Gold Mine, Gongguan Mercury-Antimony Mine, and Laojunmiao Gold Mine, and also determines the spatial migration direction of fluids based on these patterns.

[0045] Figure 5 The stable sulfur isotope variation of metal sulfides formed in the Xiaohe gold mine from early to late period;

[0046] Figure 6 This study investigates the spatial variation patterns of stable isotopes formed from gold and mercury-antimony deposits within the region. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] like Figure 1 and Figure 2 As shown, the present invention provides a method for determining the direction of fluid migration in hydrothermal deposits, comprising the following steps:

[0049] Step 100: Select an area with the same mineralization background and the same hydrothermal system as the study area, and select two or more hydrothermal deposits with a relationship within the study area;

[0050] Step 200: Collect hydrothermal mineral samples from each hydrothermal deposit and analyze them separately. Determine and mark the mineralization period corresponding to each hydrothermal mineral sample. Based on the mineralization period of each hydrothermal mineral sample and the spatial relative position of each hydrothermal mineral sample in the hydrothermal deposit, determine the mineral formation sequence corresponding to the ore minerals in the hydrothermal deposit.

[0051] Step 300: Conduct stable isotope tests on hydrothermal mineral samples before mineralization, during mineralization, and after mineralization to determine the variation patterns of stable isotopes of minerals in different mineralization stages before mineralization, during mineralization, and after mineralization.

[0052] Step 400: Compare and study the mineral stable isotope variation patterns of hydrothermal mineral samples from two or more selected hydrothermal deposits. The direction in which the mineral stable isotope variation patterns in the hydrothermal deposit tend to be consistent is taken as the fluid migration direction, and the opposite direction of the fluid migration direction is taken as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0053] Step 500: Verify the variation patterns of stable isotopes of minerals in different mineralization stages obtained in Step 300 and the fluid migration direction obtained in Step 400 by analyzing the variation direction of sulfur isotope content in hydrothermal mineral samples within the hydrothermal deposit.

[0054] In step 100, the method for selecting hydrothermal deposits is as follows:

[0055] Based on regional geological survey data and geophysical and geochemical data, study areas with the same metallogenic background were selected, and geochemical exploration was carried out in the study areas to determine that the selected study areas are located in the same tectonic-hydrothermal background.

[0056] By using hydrothermal alteration characteristics or deposit types, it can be determined whether the hydrothermal deposits in the selected study area belong to the same system, and then two or more hydrothermal deposits belonging to the same hydrothermal system can be selected.

[0057] Furthermore, the method for selecting two or more hydrothermal deposits of the same system is as follows: from within the study area, select two or more hydrothermal deposits that are related in vertical and / or horizontal space, wherein the two or more hydrothermal deposits that are related indicate that the hydrothermal deposits have the same geochemical anomaly and are located in the same regional structure.

[0058] By studying regional geological data, especially by integrating relevant literature on typical mineral deposits, such as geochemical background, ore-controlling structures, and geophysical data, and combining these data, it was determined that mineral deposits with the same geochemical anomalies and located in the same regional structure were identified.

[0059] In step 200, ore deposit studies are conducted on two or more selected hydrothermal deposits. Hydrothermal mineral samples are collected from the hydrothermal deposits, and based on the macroscopic and microscopic characteristics of the ore minerals, the hydrothermal mineral samples at different mineralization stages are classified as pre-mineralization, mineralization period, and post-mineralization hydrothermal minerals. The specific implementation method is as follows:

[0060] Multiple hydrothermal mineral samples were collected from the hydrothermal deposit, and all hydrothermal mineral samples were ground into smooth thin sections.

[0061] Thin sections of all hydrothermal mineral samples were examined under a transmitted light and reflected light microscope to identify the mineralization sequence and current mineralization stage of the samples. The specific location of the collected hydrothermal mineral samples within the hydrothermal deposit was also marked, along with the corresponding mineralization stage, which was categorized as pre-mineralization, mineralization period, and post-mineralization.

[0062] When collecting multiple hydrothermal mineral samples from a hydrothermal deposit, the collected samples have a certain spatial distribution relationship. By selecting typical deposits for study, we first determine the cross-cutting relationship of veins at the macroscopic level, and then determine the order of formation of each vein to divide the mineralization period at the macroscopic level. Based on the mineralization period, the hydrothermal deposit can be divided into minerals and ores in different periods before mineralization, during mineralization, and after mineralization.

[0063] Hydrothermal mineral samples were collected from different periods before, during, and after mineralization. These samples were then subjected to laboratory identification. Based on microscopic mineral cross-cutting relationships, the chronological order of mineral formation during the mineralization period was determined, and a mineral formation sequence table was compiled. Figure 3 As shown.

[0064] In step 300, stable isotope tests are performed on hydrothermal mineral samples collected from each hydrothermal deposit, or stable isotope tests are performed on single minerals selected from each hydrothermal deposit to determine the stable isotope characteristics formed in different mineralization stages within each hydrothermal deposit.

[0065] The stable isotope test results are marked on the sampling location of the hydrothermal deposit to determine the variation characteristics of hydrothermal mineral samples corresponding to different mineralization stages before mineralization, during mineralization, and after mineralization.

[0066] Furthermore, when collecting hydrothermal mineral samples from hydrothermal deposits, the collection work is calibrated on a regional-scale profile, and the spatial relative position corresponding to each sampling work is determined.

[0067] By analyzing the regional scale variations of stable isotopes in different hydrothermal mineral samples, this study aims to obtain the variation patterns of stable isotopes at the regional profile scale and to demonstrate the isotopic variation patterns during fluid migration in hydrothermal deposits.

[0068] The method for performing stable isotope testing on hydrothermal mineral samples collected from each hydrothermal deposit is as follows:

[0069] A stable gas isotope mass spectrometer was used to detect the hydrogen and oxygen isotopes in each hydrothermal mineral sample, and the detection results of the hydrogen and oxygen isotopes were marked on the spatial relative position of the hydrothermal mineral sample within the hydrothermal deposit.

[0070] Based on the range of hydrogen and oxygen isotope content corresponding to different spatial relative positions of hydrogen and oxygen isotopes in the same hydrothermal deposit, the variation in the hydrothermal process of the same hydrothermal deposit is determined based on the variation law of the range of hydrogen and oxygen isotope content.

[0071] Based on the range of hydrogen and oxygen isotope content corresponding to the same mineralization stage in two or more selected hydrothermal deposits, the fluid migration direction corresponding to the same mineralization stage in different hydrothermal deposits is determined based on the variation law of hydrogen and oxygen isotope content range. That is, by comparing the variation law of hydrogen and oxygen isotopes of hydrothermal mineral samples corresponding to the same mineralization stage in two or more hydrothermal deposits, the direction in which the hydrogen and oxygen isotope variation law tends to be consistent is taken as the fluid migration direction, and the opposite direction of the fluid migration direction is taken as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0072] It should be further noted that the stable isotopes involved in this invention mainly refer to hydrogen and oxygen isotopes. Hydrogen and oxygen isotope analysis was performed using a stable gas isotope mass spectrometer / 253plus, following the standards DZ / T 0184.19-1997 "Determination of Hydrogen Isotope in Water by Zinc Reduction Method" and DZ / T 0184.20-1997 "Determination of Oxygen Isotope Composition in Water and Oxygen-Free Mineral Inclusions by Bromine Pentafluoride Method". The accuracy of oxygen isotope testing was ±0.2‰, and the accuracy of hydrogen isotope testing was ±2‰.

[0073] The principle of determining the migration direction of hydrothermal fluids by changes in hydrogen and oxygen isotopes is as follows: the stable isotopes of hydrothermal fluids at different end members are different. Simply put, mineral-bearing hydrothermal fluids have independent stable isotopic compositions. During the migration process, they undergo water-rock reactions with the strata along the fluid migration path. Since the formation water often contains components of atmospheric precipitation, this will result in the mixing of the mineral-bearing hydrothermal fluid with the atmospheric precipitation end, forming a changing hydrogen and oxygen isotopic composition, which can reflect the migration path of the fluid.

[0074] In this invention, by utilizing the variation patterns of hydrogen and oxygen isotopes, it is possible to determine the variation patterns of these isotopes in different mineralization stages, as well as the variation patterns of these isotopes in different directions of hydrothermal deposits, thereby determining the fluid migration direction between different hydrothermal deposits.

[0075] Specifically, the method for determining the variation patterns of hydrogen and oxygen isotopes in different mineralization stages is as follows: determine the hydrogen and oxygen isotope content of hydrothermal mineral samples corresponding to different mineralization stages within the same hydrothermal deposit, determine the isotope evolution trend, compare the isotope variation patterns based on the relative positions of the spatial scale within the hydrothermal deposit, and then use the equilibrium fractionation and kinetic fractionation characteristics of stable isotopes to reveal the changes of stable isotopes in the hydrothermal processes of the same hydrothermal deposit.

[0076] The method for determining the direction of fluid migration between different hydrothermal deposits is as follows: compare the stable isotope variation patterns of hydrothermal mineral samples corresponding to each mineralization stage within two or more hydrothermal deposits, and take the direction in which the stable isotope variation patterns tend to be consistent as the direction of fluid migration. That is, use the same type of stable isotopes from two or more hydrothermal deposits to compare and determine the direction of fluid migration, select multiple stable isotopes for verification, determine the stable isotope variation patterns of minerals at each mineralization stage of two or more hydrothermal deposits, take the direction in which the stable isotope variation patterns tend to be consistent as the direction of fluid migration, and take the opposite direction of fluid migration as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0077] If the range of hydrogen isotope composition during the mineralization period of different deposits is inconsistent, an overall evolution trend is determined based on their relative variation trends. This case involves the range of hydrogen isotope variation during the mineralization period of multiple deposits. The evolution trend is determined based on the relative magnitude. By comparing the stable isotope variation patterns of different deposits with the above trends, the stable isotope evolution trend between two or more deposits is finally determined.

[0078] Determining the evolution trend of isotopes, such as Figure 4 As shown, point A represents the Xiaohe Gold Mine, point B represents the Wangzhuang Gold Mine, point C represents the Gongguan Mercury-Antimony Mine, and point D represents the Laojunmiao Gold Mine. Points A and B are located in the western spatial position within the study area, while points C and D are located in the eastern spatial position within the study area. By comparing the isotope variation patterns, it was determined that the fluid migration direction within the selected hydrothermal deposits in the study area is from west to east.

[0079] In step 500, the method for verifying the variation pattern of stable isotopes of minerals in different mineralization stages obtained in step 300 by the variation direction of sulfur isotope content in hydrothermal mineral samples within the hydrothermal deposit is as follows:

[0080] When collecting hydrothermal mineral samples from hydrothermal deposits, the collection work is calibrated on a regional-scale profile, and the spatial relative position corresponding to each sampling work is determined.

[0081] Identify the mineralization stage corresponding to the collected hydrothermal mineral samples;

[0082] Laser etching was performed on the collected hydrothermal mineral samples, followed by sulfur isotope testing.

[0083] Determine the sulfur isotope variation patterns of hydrothermal mineral samples from different mineralization stages.

[0084] The specific method for sulfur isotope testing is as follows: Sulfur isotopes are analyzed using the LA-MC-ICP-MS method. The laser ablation system is a 193nm excimer laser ablation system (RESOlution M-50, ASI), employing multiple receiver inductively coupled plasma mass spectrometry (NuPlasma 1700MC-ICP-MS). The resolution for S isotope testing is greater than 12000, the laser energy density is 3.6 J / cm², the ablation frequency is 3Hz, and the ablation spot beam is 30-37 μm. The standard sample used for value determination is IAEA-S-1, with an accuracy better than 0.1‰. While different laboratories may use slightly different methods, the general principles are the same.

[0085] This study selected the Xiaohe gold deposit within the study area as a typical deposit and conducted stable sulfur isotope testing, such as... Figure 5 As shown, the sulfur isotope composition of each mineralization stage (namely, the early mineralization quartz vein stage, pyrite, arsenopyrite, quartz vein stage, and quartz vein-sulfide stage) shows an evolution trend from high to low.

[0086] In step 500, the method for verifying the fluid migration direction obtained in step 400 by the change direction of sulfur isotope content in hydrothermal mineral samples within the hydrothermal deposit is as follows:

[0087] Collect hydrothermal mineral samples from two or more hydrothermal deposits and determine the mineralization stage corresponding to each hydrothermal mineral sample;

[0088] Laser etching was performed on the collected hydrothermal mineral samples, followed by sulfur isotope testing.

[0089] Determine the sulfur isotope variation patterns of two or more hydrothermal deposits at each mineralization stage, take the direction in which the sulfur isotope variation patterns tend to be consistent as the fluid migration direction, and take the opposite direction of the fluid migration direction as the source region direction of the ore-forming fluid of the hydrothermal deposit.

[0090] By selecting a gold deposit located in the western part of the study area and a mercury-antimony deposit located in the eastern part, and comparing the sulfur isotope ranges of the gold deposit in the west and the mercury-antimony deposit in the east during their mineralization period, it was determined that the sulfur isotope content evolved from low to high from east to west. Specifically, as shown below... Figure 6 As shown, this specifically refers to the sulfur isotope range during the mineralization period of the three deposits in the area: the Carlin-type gold deposit, the Qingtonggou mercury-antimony deposit, and the Gongguan mercury-antimony deposit.

[0091] Combination Figure 5 The sulfur isotope composition of the formed sulfur isotopes shows an evolution trend from high to low across the three mineralization stages: pre-mineralization, mineralization, and post-mineralization. This indicates that the migration direction of the ore-forming hydrothermal fluids in the study area was from west to east. Figure 4 The evolutionary trends formed are consistent.

[0092] Step 400 determined the variation of stable hydrogen and oxygen isotopes from west to east, showing a trend towards greater negativity. Based on regional data, the strata in this area exhibit a relatively negative isotopic composition. This indicates that the original fluid gradually mixed with more negatively isotopic fluids, and the fluid migration direction was from west to east, or vice versa. For verification, using sulfur isotopes, the regional strata have a relatively uniform isotopic composition, which is easily measured. Therefore, the exchange of sulfur with the strata during fluid migration will create a trend. Measuring this trend allows us to determine the direction of fluid migration, which can then be corrected against the aforementioned hydrogen and oxygen isotope variations.

[0093] This implementation method uses the variation law of stable isotopes as an effective means of tracing the source of hydrothermal fluids in mineral deposit formation, and uses two or more stable isotopes to cross-verify each other, which may effectively indicate the migration path or direction of fluids in regional mineral deposits.

[0094] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A method for determining the direction of fluid migration in hydrothermal deposits, characterized in that, Includes the following steps: Step 100: Select an area with the same mineralization background and the same hydrothermal system as the study area, and select two or more hydrothermal deposits with a relationship within the study area; Step 200: Collect hydrothermal mineral samples from each of the hydrothermal deposits, analyze the hydrothermal mineral samples respectively, determine and mark the mineralization period corresponding to each hydrothermal mineral sample, and determine the mineralization sequence corresponding to the ore minerals in the hydrothermal deposit based on the mineralization period of each hydrothermal mineral sample and the spatial relative position of each hydrothermal mineral sample in the hydrothermal deposit, and determine the current mineralization stage of the hydrothermal mineral sample. Step 300: Conduct stable isotope tests on hydrothermal mineral samples before mineralization, during mineralization, and after mineralization to determine the variation patterns of stable isotopes of minerals among hydrothermal mineral samples at different mineralization stages before mineralization, during mineralization, and after mineralization. Specifically, stable isotope tests are performed on hydrothermal mineral samples collected from each hydrothermal deposit, or stable isotope tests are performed on single minerals selected from each hydrothermal deposit to determine the stable isotope characteristics formed in different mineralization stages within each hydrothermal deposit. Step 400: Compare and study the mineral stable isotope variation patterns of hydrothermal mineral samples in two or more selected hydrothermal deposits. The direction that tends to be consistent with the mineral stable isotope variation patterns in the hydrothermal deposits in Step 300 is taken as the fluid migration direction, and the opposite direction of the fluid migration direction is taken as the source region direction of the ore-forming fluid of the hydrothermal deposit. Specifically, determine the range of hydrogen and oxygen isotope content corresponding to the same mineralization stage in two or more selected hydrothermal deposits, and determine the fluid migration direction corresponding to the same mineralization stage in different hydrothermal deposits based on the variation law of hydrogen and oxygen isotope content range. That is, compare the hydrogen and oxygen isotope variation law of hydrothermal mineral samples corresponding to the same mineralization stage in two or more hydrothermal deposits. Step 500: Verify the variation patterns of stable isotopes of minerals at different mineralization stages obtained in step 300 and the fluid migration direction obtained in step 400 by measuring the variation direction of sulfur isotope content in hydrothermal mineral samples within the hydrothermal deposit.

2. The method for determining the direction of fluid migration in hydrothermal deposits according to claim 1, characterized in that, In step 100, the method for selecting areas with the same mineralization background and the same hydrothermal system as the study area is as follows: Based on regional geological survey data and geophysical and geochemical data, study areas with the same metallogenic background were selected, and geochemical exploration was carried out in the study areas to determine that the selected study areas are located in the same tectonic-hydrothermal background. Use hydrothermal alteration characteristics or deposit type to determine whether the hydrothermal deposits in the selected study area belong to the same hydrothermal system, and select two or more hydrothermal deposits that belong to the same hydrothermal system.

3. The method for determining the direction of fluid migration in hydrothermal deposits according to claim 2, characterized in that, The method for selecting two or more hydrothermal deposits in the same hydrothermal system is as follows: select two or more hydrothermal deposits that are spatially related from within the study area; The space includes vertical space and / or horizontal space; Two or more hydrothermal deposits that are related refer to hydrothermal deposits that have the same geochemical anomaly and are located in the same tectonic region.

4. The method for determining the direction of fluid migration in hydrothermal deposits according to claim 1, characterized in that, In step 200, mineral deposit studies are conducted on two or more selected hydrothermal deposits. Hydrothermal mineral samples are collected from the hydrothermal deposits, and based on the macroscopic and microscopic characteristics of the ore minerals in the hydrothermal deposits, the hydrothermal mineral samples are classified into different mineralization stages: pre-mineralization, mineralization period, and post-mineralization. The specific implementation method is as follows: Multiple hydrothermal mineral samples were collected from the hydrothermal deposit, and all hydrothermal mineral samples were ground into thin sections. Thin sections of all hydrothermal mineral samples were examined under a transmitted light and reflected light microscope to identify the mineralization sequence of hydrothermal minerals at different mineralization stages and to determine the current mineralization stage of the hydrothermal mineral samples. The specific location of the collected hydrothermal mineral samples in the hydrothermal deposit, as well as the corresponding mineralization stage, are marked.

5. A method for determining the direction of fluid migration in hydrothermal deposits according to claim 4, characterized in that, The stable isotope test results are marked on the sampling location of the hydrothermal deposit to determine the variation characteristics of the hydrothermal mineral samples corresponding to different mineralization stages before mineralization, during mineralization, and after mineralization.

6. The method for determining the direction of fluid migration in hydrothermal deposits according to claim 1, characterized in that, In step 500, the method for verifying the variation pattern of stable isotopes of minerals in different mineralization stages obtained in step 300 by the variation direction of sulfur isotope content in hydrothermal mineral samples within the hydrothermal deposit is as follows: When collecting hydrothermal mineral samples from the hydrothermal deposit, the collection work is calibrated on a regional scale profile, and the spatial relative position corresponding to each sampling work is determined. Identify the mineralization stage corresponding to the collected hydrothermal mineral samples; The collected hydrothermal mineral samples were subjected to laser etching and sulfur isotope testing. The study aims to determine the sulfur isotope variation patterns of hydrothermal mineral samples from different mineralization stages, specifically the sulfur isotope variation patterns before, during, and after mineralization.

7. A method for determining the direction of fluid migration in hydrothermal deposits according to claim 5, characterized in that, In step 500, the method for verifying the fluid migration direction obtained in step 400 by the change direction of sulfur isotope content in the hydrothermal mineral sample within the hydrothermal deposit is as follows: Hydrothermal mineral samples were collected from two or more of the aforementioned hydrothermal deposits, and the mineralization stage corresponding to each hydrothermal mineral sample was determined. The collected hydrothermal mineral samples were subjected to laser etching and sulfur isotope testing. The sulfur isotope variation patterns of two or more hydrothermal deposits in the same mineralization stage are determined. The direction in which the sulfur isotope variation patterns before, during, and after mineralization tend to be consistent is taken as the fluid migration direction, and the opposite direction of the fluid migration direction is taken as the source region direction of the ore-forming fluid of the hydrothermal deposit.

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