X-ray diffraction-based method for prospecting mvt lead-zinc deposits

Abstract

The present application relates to a rapid prospecting prediction method for MVT lead-zinc deposits based on X-ray diffraction, and belongs to the technical field of prospecting prediction. Dolomite samples at different sampling points in the carbonate rock region of the wall rock of the MVT lead-zinc deposit are ground into powder or thinned into flakes to obtain dolomite powder samples or dolomite flake samples at different sampling points; the dolomite powder samples or dolomite flake samples at different sampling points are respectively subjected to X-ray diffraction scanning to obtain XRD spectra of dolomite at different sampling points; the XRD spectra of dolomite at different sampling points are subjected to phase retrieval and quantitative analysis by using MDI Jade software to identify the content of dolomite, i.e. the dolomitization intensity, in the dolomite powder samples or dolomite flake samples at different sampling points; and the intensity change tracking line is drawn according to the dolomitization intensity from low to high, the closer the dolomitization intensity is to 100%, the closer the position of the dolomite sample is to the ore body, so that the rapid prospecting prediction of the MVT lead-zinc deposit can be realized.

Description

Technical Field

[0001] This invention relates to a rapid prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction, belonging to the field of prospecting and prediction technology. Background Technology

[0002] The MVT lead-zinc deposit is an epigenetic hydrothermal lead-zinc deposit where the host rocks are mainly carbonate rocks. Carbonate minerals are the main gangue minerals in carbonate-hosted lead-zinc deposits. During the mineralization process of carbonate-type lead-zinc deposits, carbonate minerals (rocks) participate in the entire formation process and record the fluid information of the corresponding mineralization stages. Carbonate minerals (rocks) play a crucial role in the entire mineralization process of carbonate-type lead-zinc deposits, manifested in the following ways: 1) Before mineralization, water / rock interaction occurs between carbonate rocks and ore-forming fluids, resulting in large-scale dolomite (lithification), which prepares the necessary conditions for mineralization in terms of lithology, materials, and space; 2) During the mineralization period, the hydrothermal carbonate mineral dissolution-recrystallization (CO2 degassing) cycle buffers the changes in the mineralization environment (such as pH) caused by the large-scale precipitation of metal minerals, promoting the formation of a large number of snowflake-shaped (calcite / dolomite spots) characteristic ores; 3) After mineralization, carbonate minerals fill and cement mineralization sites, which is conducive to ore preservation and also becomes an important indicator mineral for prospecting.

[0003] In existing literature, the steps of using carbonate minerals as key mineral prospecting markers to locate carbonate-type lead-zinc deposits include: Step 1, field screening: classifying carbonate minerals (rocks) developed on the deposit surface and in tunnels according to macroscopic characteristics, systematically collecting (quasi-)syngenetic dolomite, burial-stage dolomite, and hydrothermal dolomite according to their distribution, marking the coordinates of sampling points, and taking photos; Step 2, indoor screening: performing cathodoluminescence observation on the obtained carbonate mineral samples to identify carbons with concentric brown-red and dark red cathodoluminescence bands. Step 3: Identify rare earth element geochemical indicators: Perform solution-based or LA-ICPMS in-situ rare earth element geochemical analysis on the key mineral exploration indicator carbonate minerals to obtain rare earth element composition data, and construct a chondrite-normalized distribution diagram of rare earth elements to determine rare earth element index parameters; Step 4: Identify carbon-oxygen-strontium isotope geochemical indicators: Perform carbon-oxygen-strontium isotope composition analysis on the key mineral exploration indicator carbonate minerals to obtain δ¹⁸O₂O₃ ... 13 C、δ 18 O and 87 Sr / 86Sr value, determine carbon-oxygen-strontium isotope parameters; Step 5, draw mineral exploration anomaly maps: establish a mineral exploration geochemical index system and draw anomaly maps to guide mineral exploration. However, the literature requires rare earth element geochemical analysis of carbonate minerals from the macroscopic scale in the field to the microscopic scale in laboratory experiments, rare earth element chondrite-normalized distribution diagrams, and determination of rare earth element index parameters. It requires mineral exploration based on carbon-oxygen-strontium isotope parameters, which is cumbersome and difficult to analyze. Summary of the Invention

[0004] To address the challenges in prospecting and prediction of existing MVT lead-zinc deposits, this invention provides a rapid prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction. Dolomite is the main host rock in MVT lead-zinc deposits. This invention links the degree of dolomitization of the host rock with the mineralization of MVT lead-zinc deposits. Based on the changes in dolomite content (i.e., dolomitization intensity) in dolomite at different sampling points, the relationship between the degree of dolomitization of dolomite and the ore body of the MVT lead-zinc deposit is established, and prospecting prediction is performed through changes in the degree of dolomitization.

[0005] The specific steps of the rapid prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction are as follows:

[0006] (1) Fresh dolomite samples from different sampling points in the carbonate rock area surrounding the MVT lead-zinc deposit were selected, ground into powder or made into thin slices to obtain dolomite powder samples or dolomite thin slice samples from different sampling points; Selecting fresh dolomite samples can avoid the influence of weathering and pollution on the experimental results.

[0007] (2) X-ray diffraction scanning was performed on dolomite powder samples or dolomite thin section samples from different sampling points to obtain XRD spectra of dolomite from different sampling points.

[0008] (3) Using MDI Jade software, phase retrieval and quantitative analysis were performed on the XRD spectra of dolomite from different sampling points to identify the dolomite content, i.e., the dolomitization intensity, in the dolomite from different sampling points. Based on the dolomitization intensity from low to high, intensity change tracking lines were drawn. The closer the dolomitization intensity is to 100%, the closer it is to the ore body, thus realizing rapid prospecting and prediction of MVT lead-zinc deposits.

[0009] The particle size of the dolomite powder sample in step (1) is less than 200 mesh.

[0010] In step (1), the dolomite powder sample is selected from 3-5g dolomite blocks on carbonate rock samples, avoiding areas where other minerals are developed.

[0011] In step (1), the dolomite thin section sample is selected from a block sample of dolomite area, avoiding areas where other minerals are developed;

[0012] The X-ray diffraction scanning conditions for the dolomite powder sample in step (2) are as follows: Cu target The step size is 0.026°, and the test range (2θ) is 5–90°.

[0013] The X-ray diffraction scanning conditions for the dolomite thin section sample in step (2) are as follows: Cu target The step size is 0.026°, the test range (2θ) is 5–90°, and the grazing angle is 0.8°.

[0014] The step (3) involves using the MDI Jade software, which is MDI Jade 2022, paired with the PDF card PDF-4+2022.

[0015] The beneficial effects of this invention are:

[0016] (1) This invention links the dolomitization degree of the host rock with the mineralization of the MVT lead-zinc deposit. Based on the changes in dolomite content, i.e. dolomitization intensity, in dolomite at different sampling points, the relationship between the dolomitization degree of dolomite and the ore body of the MVT lead-zinc deposit is established.

[0017] (2) This invention utilizes X-ray diffraction to rapidly and accurately identify the dolomitization intensity of dolomite in mineral deposits, clarify the changes in the intensity of dolomitization of dolomite, reflect the mineralization process, and make mineral exploration predictions through changes in the degree of dolomitization. Attached Figure Description

[0018] Figure 1 XRD pattern and dolomite content analysis of the powder sample from the far end of the ore in Example 2;

[0019] Figure 2 The XRD pattern and dolomite content analysis of the powder sample in the middle region of Example 2;

[0020] Figure 3 XRD pattern and dolomite content analysis of the powder sample near the ore end in Example 2;

[0021] Figure 4 The XRD pattern and dolomite content analysis of the sample from the far end of Example 3 are shown.

[0022] Figure 5 The XRD pattern and dolomite content analysis of the powder sample in the middle region of Example 3;

[0023] Figure 6 The XRD pattern and dolomite content analysis of the powder sample near the ore end in Example 3 are shown. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0025] Example 1: A prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction, the specific steps of which are as follows:

[0026] (1) Fresh dolomite samples were selected from different sampling points in the carbonate rock area of ​​the MVT lead-zinc deposit. The samples were ground into powder with a particle size of less than 200 mesh or ground into thin slices to obtain dolomite powder samples or dolomite thin slice samples from different sampling points. Selecting fresh dolomite samples can avoid the influence of weathering and pollution on the experimental results. Among them, the dolomite powder samples were selected from 3-5g dolomite blocks on the carbonate rock samples, avoiding areas where other minerals are developed. The dolomite thin slice samples were selected from blocks in the dolomite area, avoiding areas where other minerals are developed.

[0027] (2) X-ray diffraction scans were performed on dolomite powder samples or dolomite thin section samples from different sampling points to obtain XRD patterns of dolomite from different sampling points; the X-ray diffraction scan conditions for the dolomite powder samples were: Cu target The step size was 0.026°, and the test range (2θ) was 5–90°. The X-ray diffraction scanning conditions for the dolomite thin section samples were: Cu target. The step size is 0.026°, the test range (2θ) is 5–90°, and the grazing angle is 0.8°.

[0028] (3) Using MDI Jade software, phase retrieval and quantitative analysis were performed on the XRD spectra of dolomite from different sampling points to identify the dolomite content, i.e., the dolomitization intensity, in the dolomite from different sampling points. Based on the dolomitization intensity from low to high, intensity change tracking lines were drawn. The closer the dolomitization intensity is to 100%, the closer it is to the ore body, thus realizing the prospecting prediction of MVT lead-zinc deposits. The MDI Jade software is MDI Jade2022 with PDF card PDF-4+2022.

[0029] Example 2: This example uses the Middle Carboniferous Weining Formation (760-section) of a lead-zinc deposit in northeastern Yunnan as an example. This deposit is located in the north-central part of the eastern Yunnan depression zone on the southwestern margin of the Yangtze Platform. The bedrock of the Middle Carboniferous Weining Formation is limestone, and large-scale dolomitization has occurred, with most of the lead-zinc ore bodies hosted in the dolomite. For this deposit, no prospecting prediction has yet been conducted from the perspective of the dolomite, the host rock. This example uses the method from Example 1 to perform X-ray diffraction analysis on carbonate rock samples of the deposit. The dolomitization intensity is compared using the obtained XRD patterns, and an intensity change trajectory is drawn from low to high. The closer the dolomitization intensity is to 100%, the closer it is to the ore body, thus achieving MVT lead-zinc deposit prospecting prediction.

[0030] The specific steps of the MVT lead-zinc deposit prospecting prediction method based on X-ray diffraction are as follows:

[0031] (1) Fresh dolomite samples were selected from different sampling points in the carbonate rock area of ​​the MVT lead-zinc deposit. In this embodiment, three fresh dolomite samples were selected from the far end to the near end of the mining area. The samples were ground into powder with an agate mortar until the particle size was less than 200 mesh to obtain dolomite powder samples from three different sampling points (far end, middle area and near end of the mining area). Selecting fresh dolomite samples can avoid the influence of weathering and pollution on the experimental results. The dolomite powder samples were selected from 5g dolomite blocks on carbonate rock samples, avoiding areas where other minerals are developed.

[0032] (2) X-ray diffraction scans were performed on dolomite powder samples from three different sampling points (far ore end, middle region, and near ore end) to obtain XRD patterns of dolomite from different sampling points; the X-ray diffraction scan conditions for the dolomite powder samples were: Cu target The step size is 0.026°, and the test range (2θ) is 5–90°.

[0033] (3) Using MDI Jade software, phase retrieval and quantitative analysis were performed on the XRD spectra of dolomite from different sampling points to identify the dolomite content, i.e., the dolomitization intensity, in the dolomite from different sampling points. Based on the dolomitization intensity from low to high, intensity change tracking lines were drawn. The closer the dolomitization intensity is to 100%, the closer it is to the ore body, thus realizing the prospecting prediction of MVT lead-zinc deposits. The MDI Jade software is MDI Jade2022 with PDF card PDF-4+2022.

[0034] The XRD pattern and dolomite content analysis of the distant ore sample in this embodiment are shown below. Figure 1 The dolomite content in the dolomite sample was 79%; the XRD pattern and dolomite content analysis of the sample from the middle region are shown below. Figure 2 The dolomite content in the dolomite sample was 90%; the XRD pattern and dolomite content analysis of the near-ore end sample are shown below. Figure 3 The dolomite content in the dolomite sample was 94.8%, and the calcite content was almost 0, indicating that the surrounding rock near the ore end was fully dolomitized. From the far ore end to the near ore end, the degree of dolomitization of the surrounding rock gradually increased. Based on the dolomitization intensity from low to high, an intensity change tracking line was drawn. The closer the dolomitization intensity is to 100%, the closer it is to the ore body (near ore end), thus realizing the prospecting prediction of the MVT lead-zinc deposit.

[0035] In this embodiment, X-ray diffraction analysis was performed on dolomite powder samples, and XRD patterns of the Carboniferous Weining Formation from the far end to the near end of the ore body in a lead-zinc deposit in northeastern Yunnan were obtained. The dolomite content was analyzed based on the XRD patterns. By comparing the dolomitization intensity, it was found that the dolomitization intensity gradually increases from the far end to the near end, and the degree of dolomitization of the surrounding rock in the area close to the ore body will increase, thus realizing the prospecting prediction of MVT lead-zinc deposits.

[0036] Example 3: This example uses the Middle Carboniferous Weining Formation (610 section) of a lead-zinc deposit in northeastern Yunnan as an example. This deposit is located in the north-central part of the eastern Yunnan depression zone on the southwestern margin of the Yangtze Platform. The bedrock of the Middle Carboniferous Weining Formation is limestone, which has undergone large-scale dolomitization. Most of the lead-zinc ore bodies are hosted in the dolomite. For this deposit, no prospecting prediction has yet been conducted from the perspective of the dolomite, the host rock. This example uses the method from Example 1 to perform X-ray diffraction analysis on carbonate rock samples of the deposit. By comparing the dolomitization intensity using the obtained XRD patterns, an intensity change trajectory is drawn from low to high. The closer the dolomitization intensity is to 100%, the closer it is to the ore body, thus achieving MVT lead-zinc deposit prospecting prediction.

[0037] The specific steps of the MVT lead-zinc deposit prospecting prediction method based on X-ray diffraction are as follows:

[0038] (1) Fresh dolomite samples were selected from different sampling points in the carbonate rock area surrounding the MVT lead-zinc deposit. In this embodiment, three fresh dolomite samples were selected from the far end to the near end of the mining area. Three dolomite probe specimens were obtained from three different sampling points (far end, middle area and near end of the mining area) by grinding thin sections. Selecting fresh dolomite samples can avoid the influence of weathering and pollution on the experimental results. The samples of dolomite probe specimens were selected from dolomite blocks on carbonate rock samples, avoiding areas where other minerals are developed.

[0039] (2) X-ray diffraction scans were performed on dolomite probe samples from three different sampling points (far ore end, middle region, and near ore end) to obtain XRD patterns of dolomite from different sampling points; the X-ray diffraction scan conditions for the dolomite powder samples were: Cu target The step size is 0.026°, the test range (2θ) is 5–90°, and the grazing angle is 0.8°.

[0040] (3) Using MDI Jade software, phase retrieval and quantitative analysis were performed on the XRD spectra of dolomite from different sampling points to identify the dolomite content, i.e., the dolomitization intensity, in the dolomite from different sampling points. Based on the dolomitization intensity from low to high, intensity change tracking lines were drawn. The closer the dolomitization intensity is to 100%, the closer the dolomite sample is to the ore body. This can realize rapid prospecting and prediction of MVT lead-zinc deposits. The MDI Jade software is MDI Jade2022 with PDF card PDF-4+2022.

[0041] The XRD pattern and dolomite content analysis of the distant ore sample in this embodiment are shown below. Figure 4 The dolomite content in the dolomite sample was 51.4%; the XRD pattern and dolomite content analysis of the sample from the middle region are shown below. Figure 5 The dolomite content in the dolomite sample was 63.7%; the XRD pattern and dolomite content analysis of the near-ore end sample are shown below. Figure 6 The dolomite content in the dolomite sample was 96%, and the surrounding rock near the ore end was fully dolomitized. From the far ore end to the near ore end, the degree of dolomitization of the surrounding rock gradually increased. According to the dolomitization intensity from low to high, the intensity change line was drawn. The closer the dolomitization intensity is to 100%, the closer the dolomite sample is to the ore body (near ore end), thus realizing the prospecting prediction of MVT lead-zinc deposits.

[0042] In this embodiment, X-ray diffraction analysis was performed on dolomite powder samples, and XRD patterns of the Carboniferous Weining Formation from the far end to the near end of the ore body in a lead-zinc deposit in northeastern Yunnan were obtained. The dolomite content was analyzed based on the XRD patterns. By comparing the dolomitization intensity, it was found that the dolomitization intensity gradually increases from the far end to the near end, and the degree of dolomitization of the surrounding rock in the area close to the ore body will increase, thus realizing the prospecting prediction of MVT lead-zinc deposits.

[0043] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A rapid prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction, characterized in that: The specific steps are as follows: (1) Select dolomite samples from different sampling points in the carbonate rock area surrounding the MVT lead-zinc deposit, grind them into powder or make them into thin slices to obtain dolomite powder samples or dolomite thin slice samples from different sampling points; the MVT lead-zinc deposit is a host rock, mainly a post-hydrothermal lead-zinc deposit of carbonate rock, and carbonate minerals are the main gangue minerals of carbonate rock host type lead-zinc deposits; dolomite is the main host rock of the MVT lead-zinc deposit; (2) X-ray diffraction scanning was performed on dolomite powder samples or dolomite thin section samples from different sampling points to obtain XRD patterns of dolomite from different sampling points. (3) Using MDI Jade software, phase retrieval and quantitative analysis were performed on the XRD spectra of dolomite from different sampling points to identify the dolomite content, i.e., the dolomitization intensity, in the dolomite from different sampling points. Based on the dolomitization intensity from low to high, intensity change tracking lines were drawn. The closer the dolomitization intensity is to 100%, the closer the dolomite sample is to the ore body. This can realize rapid prospecting and prediction of MVT lead-zinc deposits.

2. The X-ray diffraction-based MVT lead-zinc deposit prospecting and prediction method according to claim 1, characterized in that: Step (1) The particle size of the dolomite powder sample is less than 200 mesh.

3. The X-ray diffraction-based MVT lead-zinc deposit prospecting and prediction method according to claim 1, characterized in that: Step (2) The X-ray diffraction scanning conditions for the dolomite powder sample are: Cu target Kα = 1.54056 The step size is 0.026°, and the test range (2θ) is 5~90°.

4. The X-ray diffraction-based MVT lead-zinc deposit prospecting and prediction method according to claim 1, characterized in that: Step (2) The X-ray diffraction scanning conditions for the dolomite thin section sample are: Cu target Kα = 1.54056 The step size is 0.026°, the test range (2θ) is 5~90°, and the grazing angle is 0.8°.

5. The rapid prospecting and prediction method for MVT lead-zinc deposits based on X-ray diffraction according to claim 1, characterized in that: Step (3) MDI Jade software is paired with MDI Jade2022 and PDF card PDF-4+2022.

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