Method for quickly locating hydrothermal mineralization center of epithermal low-temperature hydrothermal Ag-Au deposit

Abstract

This invention discloses a method for rapidly delineating the hydrothermal mineralization center of shallow-water low-temperature hydrothermal Ag-Au deposits. The method includes delineating the hydrothermal mineralization center using the trace element content characteristics of epidote in collected bedrock samples. This invention offers advantages such as short testing time, low cost, and convenience, effectively shortening the mineral exploration cycle, significantly improving the accuracy of hydrothermal mineralization center delineation at the mining scale, reducing exploration risks, and increasing mineral exploration efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of mineral exploration methods, and particularly to the technical field of exploring hydrothermal mineralization centers using characteristic mineral trace elements. Background Technology

[0002] Hydrothermal deposits are accumulations of useful minerals formed by the infilling and replacement of mineralized fluids in various favorable geological structures and rocks under specific physicochemical conditions. Hydrothermal deposits are the most complex and diverse type of mineral deposit, forming under different geological backgrounds through hydrothermal activity of varying compositions and origins. Delineating the mineralization center of hydrothermal deposits is of great significance in their exploration.

[0003] Traditional methods for delineating hydrothermal mineralization centers often have the following drawbacks: they require large-scale alteration mapping and systematic comprehensive studies in the early stages of exploration and evaluation, which are time-consuming, costly, have low accuracy, and involve a large workload, failing to meet the urgent need for rapid exploration and evaluation at the mineral area scale.

[0004] On the other hand, during the formation of magmatic hydrothermal deposits, metallic elements precipitated from hydrothermal fluids are hosted inside the intrusive body or in the surrounding rocks, resulting in a large alteration halo around the center of the deposit. Within this alteration halo, both mineral and elemental composition may exhibit certain zonation. Epidote is one of the characteristic minerals in the phyllost alteration zone of porphyry systems. It is widely distributed and usually exists as replacement of calcium-bearing minerals (such as plagioclase and amphibole) or as veins. In porphyry deposits, epidote veins mainly occur on the outer side of the quartz veinlet zone. Therefore, a detailed mapping of the spatial distribution and alteration intensity of epidote veins can be used to indicate the center of the porphyry system.

[0005] Current research on the use of epidote trace elements in mineral exploration and evaluation is mostly based on porphyry copper-gold deposits, while its application in epithermal Ag-Au deposits has not yet been developed.

[0006] Porphyry deposits are medium- to high-temperature hydrothermal deposits with mineralization temperatures >300℃. They can be divided from the inside out into potassic alteration zones, sericitization, and propylitic alteration zones, with epidote distributed in the propylitic alteration zone. Hypothermal deposits are medium- to low-temperature hydrothermal deposits with mineralization temperatures <200℃. They exhibit a single alteration zonation, with epidote distributed in the altered cap. Hypothermal deposits exhibit different mineralization physicochemical conditions than porphyry deposits, and existing methods for applying epidote trace elements in porphyry deposits are not applicable to hypothermal deposits. Summary of the Invention

[0007] The purpose of this invention is to address the deficiencies in existing technologies by providing a new method for delineating hydrothermal mineralization centers in shallow low-temperature hydrothermal Ag-Au deposits. This method uses epidote trace elements as quantitative characteristic indicators to quickly and accurately delineate hydrothermal mineralization centers within the deposit, achieving an organic combination of mineral geochemistry and target area delineation.

[0008] The technical solution of the present invention is as follows:

[0009] A method for rapidly delineating the hydrothermal mineralization center of a shallow low-temperature hydrothermal Ag-Au deposit, comprising: delineating the hydrothermal mineralization center by the characteristic values ​​of trace element content in epidote in collected bedrock samples.

[0010] According to some preferred embodiments of the present invention, the content characteristics of the trace elements include one or more of the following: the content of Zn, Sr, B, and V in the epidote.

[0011] According to some preferred embodiments of the present invention, the method includes: when the content characteristic value meets one or more of the following conditions, the corresponding sampling range is considered to be close to the hydrothermal mineralization center: the content of Zn element is 8-12 ppm, the content of Sr element is 4500-5500 ppm, the content of B element is 300-500 ppm, and the content of V element is 200-300 ppm.

[0012] According to some preferred embodiments of the present invention, the method further includes: when the content characteristic value meets one or more of the following conditions, the corresponding sampling range is considered to be far away from the hydrothermal mineralization center: the content of Zn element is 40-60 ppm, the content of Sr element is about 500-1000 ppm, the content of B element is 10-50 ppm, and the content of V element is 50-150 ppm.

[0013] According to some preferred embodiments of the present invention, the content characteristic value is obtained by in-situ micro-area elemental analysis by laser ablation inductively coupled plasma mass spectrometry.

[0014] According to some preferred embodiments of the present invention, the method specifically includes:

[0015] The system collects existing geological, geophysical, geochemical, and remote sensing data within the mining area, comprehensively analyzes its mineralization potential, delineates the alteration range, and divides the alteration area of ​​the deposit into several sampling units, each with an area of ​​1.5–2.5 km². 2 ;

[0016] Within the delineated alteration area, bedrock samples containing epidote were collected according to sampling units, with a sampling density of 1–2 samples / km². 2The sampling coordinate data, as well as the lithology, alteration and mineralization characteristics of each sample, were recorded.

[0017] The bedrock sample was subjected to microscopic feature observation, and the alteration type and chemical composition analysis data of epidote were recorded. Furthermore, the epidote development sites were selected as detection micro-areas for in-situ micro-area elemental analysis by laser ablation inductively coupled plasma mass spectrometry.

[0018] The obtained analytical data were processed, and bubble charts of the characteristic values ​​of trace elements Zn, Sr, B, and V were drawn according to lithology, alteration type, and mineral-bearing or non-mineral-bearing category. Based on their spatial distribution, the location of hydrothermal mineralization centers was delineated.

[0019] According to some preferred embodiments of the present invention, the chemical composition analysis is achieved by electron probe microanalysis.

[0020] According to some preferred embodiments of the present invention, the data processing includes:

[0021] Based on the micro-area elemental analysis data of chlorite in the bedrock samples obtained from each collection point, the corresponding micro-area elemental integral curves were obtained.

[0022] Based on the abnormal peaks in the obtained elemental integral curves, invalid data in the micro-area elemental analysis data are removed to obtain the processed data.

[0023] According to some preferred embodiments of the present invention, the abnormal peaks include abnormal peaks of Ti, Pb, Zr, Zn, and Fe elements formed by the laser ablation inductively coupled plasma mass spectrometry (LC-MS) when the inclusions are struck, and / or abnormal peaks of Mg and Na elements formed by the laser ablation LC-MS when the epidote mineral is penetrated.

[0024] According to some preferred embodiments of the present invention, the method further includes:

[0025] In the bubble diagram of Zn element, the coordinates of the chlorite sample with the lowest Zn element content are used as the first delineation center, and a radius of 400-600m is used as the delineation radius to delineate the first predicted mineralization center.

[0026] In the bubble diagram of the obtained Sr element, the coordinates of the chlorite sample with the highest Sr element content are used as the second delineation center, and a radius of 400-600m is used as the delineation radius to delineate the second predicted mineralization center.

[0027] In the bubble diagram of element B obtained, the coordinates of the chlorite sample with the highest element B content are used as the third delineation center, and a radius of 400-600m is used as the delineation radius to delineate the third predicted mineralization center.

[0028] In the bubble diagram of V element obtained, the coordinates of the chlorite sample with the highest V element content are used as the fourth delineation center, and a radius of 400-600m is used as the delineation radius to delineate the fourth predicted mineralization center.

[0029] The first to fourth predicted mineralization centers are marked in the same coordinate system, and the mineralization centers of the shallow low-temperature hydrothermal Ag-Au deposit are delineated by the boundary formed by them.

[0030] The present invention features short testing time, low cost, and convenience, which can effectively shorten the mineral exploration cycle, greatly improve the accuracy of delineation of hydrothermal mineralization centers at the mining area scale, reduce exploration risks, and improve mineral exploration efficiency. It has important value for promotion and widespread application.

[0031] In some specific embodiments, the present invention can utilize advanced LA-ICP-MS in-situ analysis technology to elevate the description of epidote, an altered mineral in magma-hydrothermal mineralization systems, from macroscopic qualitative analysis to microscopic quantitative explanation of the changes in trace elements. Furthermore, it links the changes in trace elements with the response of hydrothermal mineralization centers at the mining area scale, overcoming the difficulties of low efficiency, long cycle, and high cost of traditional methods for delineating hydrothermal mineralization centers. Attached Figure Description

[0032] Figure 1 This is a graph showing the relationship between the content of different trace elements in epidote and the distance from the mineralization center.

[0033] Figure 2 This is a schematic diagram of in-situ laser target analysis and testing of epidote.

[0034] Figure 3 This is a schematic diagram of the alteration zone of the ore deposit.

[0035] Figure 4 This is a schematic diagram for delineating and predicting hydrothermal mineralization centers based on the variation of Zn content in epidote.

[0036] Figure 5 This is a schematic diagram for delineating and predicting hydrothermal mineralization centers based on the variation of Sr element content in epidote.

[0037] Figure 6 This is a schematic diagram for delineating and predicting hydrothermal mineralization centers based on the variation of B element content in epidote.

[0038] Figure 7 A schematic diagram for delineating and predicting hydrothermal mineralization centers based on the variation of V element content in epidote.

[0039] Figure 8 This is a schematic diagram of delineating shallow low-temperature hydrothermal Ag-Au mineralization centers based on predicted mineralization centers. Detailed Implementation

[0040] The present invention will now be described in detail with reference to embodiments and accompanying drawings. However, it should be understood that the embodiments and drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0041] According to the technical solution of the present invention, some specific methods for rapidly delineating the hydrothermal mineralization center of shallow low-temperature hydrothermal Ag-Au deposits include:

[0042] (1) Data collection and comprehensive analysis of mining area

[0043] The system collects existing geological, geophysical, geochemical, and remote sensing data within the mining area, comprehensively analyzes its mineralization potential, delineates the alteration range, and divides the alteration area of ​​the deposit into several sampling units.

[0044] refer to Figure 3 In this step, the mineralized alteration region is divided into several sampling units, as shown in the small squares in the figure, with each small square representing a sampling unit; the area of ​​each sampling unit is 1.5–2.5 km². 2 This method can improve the uniformity of sampling, laying the foundation for the accurate delineation of the mineralization center of shallow low-temperature hydrothermal Ag-Au deposits.

[0045] For example, in this embodiment, the sampling unit is a small square of 1.5km × 1.5km, that is, the area of ​​each sampling unit is 2.25km². 2 .

[0046] Understandably, the area of ​​a specific sampling unit can be adjusted according to the user's needs.

[0047] (2) Collection of epidote samples

[0048] Within the selected alteration range, bedrock samples containing epidote were collected according to the divided sampling cells. Each sampling point was located using a positioning system, and coordinate data was collected. Field photos were taken, and detailed field records were made for each observation point, describing the lithology, alteration, and mineralization characteristics of each sample. This provides a basis for subsequent mapping and analysis of the obtained data according to lithology, alteration type, and mineralization content.

[0049] In this step, the sampling density within the sampling unit is 1 to 2 samples / km. 2 The coordinates of the epidote sample were marked using GPS positioning.

[0050] (3) Trace element analysis of samples

[0051] The collected bedrock samples were ground into probe slides and laser in-situ targets. The corresponding epidote alteration characteristics were observed under a microscope, and the epidote alteration types (including vein-like or disseminated types) were recorded in detail. Considering that different types of alteration come from different stages of hydrothermal activity, the purpose of recording the vein-like or disseminated alteration types here is to provide a basis for making bubble diagrams of alteration types in the subsequent data, and to ensure the reliability of data comparison.

[0052] Subsequently, electron probe microanalysis was conducted to further determine the chemical composition and type of epidote, and the mineral was labeled. Electron probe microanalysis was selected to identify epidote as a mineral, and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) in-situ micro-area elemental analysis was performed. The analyzed data included Zn, Sr, B, and V elements.

[0053] (4) Data processing and interpretation

[0054] The initial recorded data obtained in step (3) was processed using LADRlib software, including: ① Data import: the recorded data in CSV format obtained from the in-situ micro-area test points of each epidote sample were imported into LADRlib software in batches; ② Data interpretation: the micro-area elemental integral curve of the sample at each observation point was obtained, and the start and end times of the integral curve of each observation point were adjusted one by one according to the principle of ensuring the flattest and widest signal range of the selected elemental integral curve; ③ Data filtering: invalid data, such as data that hit inclusions (abnormal peaks of Ti, Pb, Zr, Zn, Fe elements) or data that penetrated epidote minerals (abnormal peaks of Mg, Na elements), were removed based on the abnormal peaks of the elemental integral curves; ④ Data export: the interpreted and filtered micro-area data of each single point were summarized and exported in batches as a CSV file.

[0055] (5) Delineation of hydrothermal mineralization centers

[0056] Based on the processed data, bubble charts for Zn, Sr, B, and V elements were drawn according to lithology, alteration type, and mineral-bearing or non-mineral-bearing category.

[0057] refer to Figures 4 to 7 In this step, using Origin software, bubble diagrams are plotted for Zn, Sr, B, and V elements, with the coordinates of the chlorite sample as the horizontal and vertical coordinates, and the bubble size as the content of trace elements in the epidote sample. The size of the bubble represents the level of trace element content in the sample, and the horizontal and vertical coordinate values ​​corresponding to the bubble center are the coordinates of the chlorite sample.

[0058] Based on the variation pattern of the trace element content, refer to the appendix. Figure 1 The predicted mineralization centers are delineated in the bubble chart, and the elemental indices of the mineralization centers are as follows:

[0059] Near the hydrothermal mineralization center: the Zn content is 8-12 ppm, the Sr content is 4500-5500 ppm, the B content is 300-500 ppm, and the V content is 200-300 ppm. That is, near the hydrothermal mineralization center, the Sr, B, and V content in epidote gradually increases, while the Zn content gradually decreases.

[0060] Far from hydrothermal mineralization centers: Zn content is 40-60 ppm, Sr content is around 500-1000 ppm, B content is 10-50 ppm, and V content is 50-150 ppm. In other words, far from hydrothermal mineralization centers, the Sr, B, and V content in epidote gradually decreases, while the Zn content gradually increases.

[0061] Furthermore, the predicted mineralization centers are delineated in the bubble diagram as follows:

[0062] In the bubble diagram of Zn element, the coordinates of the epidote sample with the lowest Zn element content are used as the delineation center, and a radius of 500m is used as the delineation radius to delineate the predicted mineralization center.

[0063] In the bubble diagram of Sr element, the coordinates of the epidote sample with the highest Sr element content are used as the delineation center, and a radius of 500m is used as the delineation radius to delineate the predicted mineralization center.

[0064] In the bubble diagram of element B, the coordinates of the epidote sample with the highest element B content are used as the delineation center, and a radius of 500m is used as the delineation radius to delineate the predicted mineralization center.

[0065] In the bubble diagram of V element, the coordinates of the epidote sample with the highest V element content are used as the delineation center, and the predicted mineralization center is delineated with a radius of 500m.

[0066] The defined radius can also be adjusted according to the user's needs.

[0067] Finally, the predicted mineralization centers identified based on the variation patterns of Zn, Sr, B, and V elemental contents are marked in the same coordinate system. The mineralization centers of the epithermal Ag-Au deposit are then delineated using the boundaries of each of the predicted mineralization centers. Figure 8 The area corresponding to the rectangular frame in the middle; thus, the delineation of the mineralization center of the shallow low-temperature hydrothermal Ag-Au deposit is completed.

[0068] Example 1

[0069] Taking an Ag-Au deposit in a certain area as an example, the process of implementing this invention includes:

[0070] a. The system collects existing geological, geophysical, geochemical, and remote sensing data within the mining area, comprehensively analyzes its mineralization potential, and delineates its alteration range to approximately 20 km. 2 The alteration area was divided into several sampling cells with a grid spacing of 1.5km × 1.5km.

[0071] b. Field sample collection:

[0072] Within the designated sampling cells defined by the alteration zone, surface epidote samples were collected. During sampling, the sample number, lithology, alteration, and mineralization information were accurately and thoroughly recorded. GPS coordinates (X and Y) were also recorded, as shown in Table 1.

[0073] Table 1

[0074] Sample number X Y Lithology Hand specimen alteration mineralization c09083 528782 3266177 Granodiorite Quartz-epidote vein Pyrite C05124 526158 3265683 Granodiorite Green Epidote Vein Pyrite 1809 523778 3267120 Granodiorite Massive Epidote none … … … … … …

[0075] c. Sample testing:

[0076] The collected samples were ground into probe sheets and laser in-situ targets. The corresponding epidote alteration characteristics were observed under a microscope, and the epidote alteration types were recorded in detail. Electron probe microanalysis was performed to further determine the chemical composition and type of epidote. The samples were then marked with a marker. Selected minerals containing epidote were subjected to in-situ micro-area elemental analysis using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). An example is attached. Figure 2 The in-situ analysis data are shown in Table 2.

[0077] d. Data processing: Data processing is performed using LADRlib software, including three steps: data import, data interpretation, and data filtering.

[0078] e. Delineate hydrothermal mineralization centers

[0079] Using Origin to process the final data, bubble charts for Zn, Sr, B, and V elements were plotted. The predicted hydrothermal mineralization centers for each element were delineated with a radius of 500m, centered on the lowest Zn value, highest Sr value, highest B value, and highest V value. These predicted mineralization centers were then marked on the same coordinate system, and their boundaries were used to delineate the locations of the mineralization centers in the epithermal Ag-Au deposit. Figure 8 As shown, it is located 2 km in the middle of the alteration zone. 2 This significantly narrowed the scope of the exploration.

[0080] Drilling has verified that the above process has achieved excellent mineral exploration results.

[0081] Table 2

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for rapidly delineating the hydrothermal mineralization center of a shallow, low-temperature hydrothermal Ag-Au deposit, characterized in that, It includes: The hydrothermal mineralization center was delineated based on the characteristic values ​​of trace element content in epidote in the collected bedrock samples. The trace element content characteristics include the contents of Zn, Sr, B, and V in the epidote. When the content characteristics meet the following conditions, the corresponding sampling range is considered to be close to the hydrothermal mineralization center: Zn content is 8-12 ppm, Sr content is 4500-5500 ppm, B content is 300-500 ppm, and V content is 200-300 ppm. When the content characteristics meet the following conditions, the corresponding sampling range is considered to be far from the hydrothermal mineralization center: Zn content is 40-60 ppm, Sr content is 500-1000 ppm, B content is 10-50 ppm, and V content is 50-150 ppm.

2. The method according to claim 1, characterized in that, The content characteristic values ​​were obtained by in-situ micro-area elemental analysis using laser ablation inductively coupled plasma mass spectrometry.

3. The method according to claim 1, characterized in that, Specifically, it includes: The system collects existing geological, geophysical, geochemical, and remote sensing data within the mining area, comprehensively analyzes its mineralization potential, delineates the alteration range (i.e., the ore deposit alteration area), and divides the ore deposit alteration area into several sampling units, each with an area of ​​1.5–2.5 km². 2 ; Within the delineated alteration area, bedrock samples containing epidote were collected according to sampling units, with a sampling density of 1-2 samples / km². 2 The sampling coordinate data, as well as the lithology, alteration and mineralization characteristics of each sample, were recorded. The bedrock sample was subjected to microscopic feature observation, and the alteration type and chemical composition analysis data of epidote were recorded. Furthermore, the epidote development sites were selected as detection micro-areas for in-situ micro-area elemental analysis by laser ablation inductively coupled plasma mass spectrometry. The obtained analytical data were processed, and bubble charts of the characteristic values ​​of trace elements Zn, Sr, B, and V were drawn according to lithology, alteration type, and mineral-bearing or non-mineral-bearing category. Based on their spatial distribution, the location of hydrothermal mineralization centers was delineated.

4. The method according to claim 3, characterized in that, The chemical composition analysis was performed using electron probe microanalysis.

5. The method according to claim 3, characterized in that, The data processing includes: Based on the micro-area elemental analysis data of epidote in the bedrock samples obtained from each collection point, the corresponding micro-area elemental integral curves were obtained. Based on the abnormal peaks in the obtained elemental integral curves, invalid data in the micro-area elemental analysis data are removed to obtain the processed data.

6. The method according to claim 5, characterized in that, The anomalous peaks include anomalous peaks of Ti, Pb, Zr, Zn, and Fe elements formed by the laser ablation inductively coupled plasma mass spectrometry (LC-MS) when the inclusions are struck, and / or anomalous peaks of Mg and Na elements formed by the laser ablation LC-MS when the epidote mineral is penetrated.

7. The method according to any one of claims 3-5, characterized in that, It also includes: In the bubble diagram of Zn element, the coordinates of the epidote sample with the lowest Zn element content are used as the first delineation center, and a radius of 400-600m is used as the delineation radius to delineate the first predicted mineralization center. In the bubble diagram of the obtained Sr element, the coordinates of the epidote sample with the highest Sr element content are used as the second delineation center, and a radius of 400-600m is used as the delineation radius to delineate the second predicted mineralization center. In the bubble diagram of element B obtained, the coordinates of the epidote sample with the highest element B content are used as the third delineation center, and a radius of 400-600m is used as the delineation radius to delineate the third predicted mineralization center. In the bubble diagram of V element obtained, the coordinates of the epidote sample with the highest V element content are used as the fourth delineation center, and a radius of 400-600m is used as the delineation radius to delineate the fourth predicted mineralization center. The first to fourth predicted mineralization centers are marked in the same coordinate system, and the mineralization centers of the shallow low-temperature hydrothermal Ag-Au deposit are delineated by the boundary formed by them.

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