A method for detecting and analyzing altered minerals in a granite type uranium deposit and for prospecting indications

Abstract

The application relates to the field of geology and mineral resources, and discloses a detection analysis and ore-prospecting indication method of altered minerals in a granite-type uranium deposit, in particular to the identification of widely developed'reddening' altered material components in the Mianhuakeng uranium deposit in the north of Guangdong and the research on the ore-prospecting indication significance of the uranium deposit. Through polarization microscope, scanning electron microscope, laser Raman, electron probe and LA-ICP-MS and other technologies, it is found that the'reddening' material in the Mianhuakeng uranium deposit is mainly composed of hematite, goethite and a small amount of magnetite. The research finds that different forms of hematite are closely related to the enrichment degree of uranium, the self-morphology-hemihedral hematite is rich in uranium mineral inclusions, and the disseminated hematite contains uranium in the form of adsorption. The application provides a theoretical basis for granite-type uranium ore prospecting, and in particular, the crystallization form and element geochemical characteristics of iron oxides (hydroxides) are used to predict the uranium mineralization potential.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological exploration, and particularly relates to a detection analysis and ore prospecting indication method for altered minerals in a granite type uranium deposit. BACKGROUND

[0002] The granite type uranium deposit is one of important uranium resource sources in the world. In the formation process of the uranium deposit, a large amount of hydrothermal alteration is often accompanied, mainly including "green" alteration and "red" alteration. The "green" alteration mainly includes hydromicazation and chloritization, and the "red" alteration mainly includes hematitization. However, these are macroscopic descriptions. From the microscopic point of view, the hydromicazation may represent a variety of clay minerals, and the hematitization may include different types of iron oxides and iron hydroxides. The specific altered minerals have different indications for uranium mineralization. Therefore, the macroscopic hydrothermal alteration characteristics need to be identified by microscopic alteration mineral identification. However, the traditional mineralogical and geochemical analysis methods have limitations in accurately determining the composition of the altered minerals and the relationship between the altered minerals and the uranium mineralization. In addition, the characteristics of trace elements and rare earth elements rich in altered minerals such as hematite, goethite and magnetite and other iron oxides (hydroxides) have important significance for revealing the properties and evolution process of the uranium mineralization fluid.

[0003] To solve the above problems, the present application provides a detection analysis and ore prospecting indication method for altered minerals in a granite type uranium deposit. SUMMARY

[0004] The present application aims to provide a detection analysis and ore prospecting indication method for altered minerals in a granite type uranium deposit to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a detection analysis and ore prospecting indication method for altered minerals in a granite type uranium deposit, comprising the following steps:

[0006] a. collecting altered minerals and ore samples in the granite type uranium deposit;

[0007] b. pretreating the collected samples to prepare thin sections or probe sections;

[0008] c. observing the samples by using a microscope to preliminarily determine the types, morphologies and paragenetic relationships of the altered minerals;

[0009] d. performing detailed mineralogical and geochemical analysis on the selected altered minerals, including using scanning electron microscopy (SEM), laser Raman spectrometer, electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and other technologies;

[0010] e. According to the analysis results, the major elements, trace elements and rare earth elements in the altered minerals are identified and quantified;

[0011] f. The genesis of the altered minerals and its relationship with uranium mineralization are analyzed to further indicate the prospecting direction of uranium deposits.

[0012] Optionally, the mineralogical and geochemical analysis in step d specifically includes detailed analysis of iron oxides (hydroxides) such as hematite, goethite and magnetite to explore their trace element and rare earth element characteristics.

[0013] Optionally, when analyzing the element content in the altered minerals in step e, special attention is paid to the content of U, Mo, W and other granite-loving elements, as well as Cr, V, Co, Ni and other transition metal elements, and the distribution pattern of rare earth elements.

[0014] Optionally, in step f, by analyzing the genesis of the altered minerals and its relationship with uranium mineralization, the properties and evolution process of the uranium mineralization fluid are identified, thereby providing a theoretical basis for further prospecting of uranium deposits.

[0015] Beneficial effects: improve detection accuracy: using advanced mineralogical, morphological and geochemical analysis techniques, accurately identify and measure the types and compositions of altered minerals, and improve detection accuracy.

[0016] Reveal the genetic relationship: by analyzing the genesis of altered minerals, reveal their internal relationship with uranium mineralization, and provide a new perspective for the genetic study of uranium deposits.

[0017] Guide the prospecting direction: based on the geochemical characteristics of altered minerals, further indicate the prospecting direction of uranium deposits, and improve the efficiency of prospecting. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Microscopic characteristics of iron oxides (hydroxides) in the Mianhuakeng uranium deposit (reflected light photo);

[0019] Figure 2 Raman spectrum of hematite and goethite in the Mianhuakeng uranium deposit;

[0020] Figure 3 Raman spectrum of hematite and goethite mixture in the Mianhuakeng uranium deposit;

[0021] Figure 4 Mineralogical characteristics of iron oxides (hydroxides) in the Mianhuakeng uranium deposit (backscattered electron image);

[0022] Figure 5 Variable diagram of FeO and UO2 (a), Al2O3 (b) and SiO2 (c) of iron oxides (hydroxides) in the Mianhuakeng uranium deposit;

[0023] Figure 6 Cotton ball uranium deposit iron oxide rare earth element distribution diagram. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present application are described below with reference to the accompanying drawings, so that the technical content of the present application is more clear and convenient to understand. The present application can be embodied in many different forms, and the protection scope of the present application is not limited to the embodiments mentioned in the text.

[0025] Example 1

[0026] A method for detecting and analyzing altered minerals in a granite-type uranium deposit and indicating prospecting

[0027] The present application provides a comprehensive detection and analysis method for altered minerals in a granite-type uranium deposit and indicating prospecting. The method combines various advanced mineralogical and geochemical analysis techniques, aiming to accurately determine the composition of altered minerals, reveal their relationship with uranium mineralization, and provide scientific basis for uranium deposit prospecting work.

[0028] I. Detailed technical scheme

[0029] (I) Sample collection and pretreatment

[0030] Sample collection

[0031] Select a geologically representative area in a granite-type uranium deposit for systematic sample collection. Considering the close relationship between altered minerals and uranium mineralization, attention should be paid to rock samples showing obvious alteration phenomena (such as red alteration). During sampling, detailed information such as the specific location of the sampling point, lithological characteristics, and alteration phenomena should be recorded, which will provide indispensable basic data for subsequent analysis.

[0032] Sample pretreatment

[0033] The collected samples are carefully washed to completely remove surface dirt and impurities. Then, the samples are professionally polished in the laboratory environment. The samples will be carefully made into thin sections (mainly for observation under optical microscope) and probe pieces (special for electron probe and laser ablation analysis). During polishing, the flatness of the sample must be ensured to the highest standard, so as to effectively avoid any errors in subsequent analysis. In addition, in order to fully guarantee the accuracy and reliability of the analysis results, each sample needs to be strictly numbered and properly stored to prevent confusion between samples.

[0034] (II) Preliminary mineralogical observation

[0035] Optical microscope observation

[0036] Place the carefully prepared thin sections under an optical microscope for careful observation. By adjusting the magnification and lighting conditions of the microscope, the types, shapes, and intergrowth relationships of the altered minerals can be clearly observed. During this process, detailed records of the morphological characteristics (such as color, luster, cleavage, etc.) and intergrowth relationships (such as inclusion, interstitial, etc.) of the minerals can be made, which are of great reference value for subsequent analysis.

[0037] Preliminary determination and recording

[0038] During the observation process, the morphological characteristics of each altered mineral need to be recorded in detail, and their potential relationship with uranium mineralization is preliminarily determined. For example, the enrichment of hematite may indicate the presence of uranium mineralization, as hematite is often one of the important carriers of uranium. At the same time, attention should be paid to the distribution pattern of altered minerals, especially in the bedding and fissures. These information will provide important clues and basis for subsequent analysis.

[0039] (Three) Detailed mineralogy and geochemistry analysis

[0040] Scanning Electron Microscope (SEM) analysis

[0041] High-resolution imaging analysis of selected altered minerals is carried out using advanced scanning electron microscope technology. SEM technology not only provides micro-morphological information of altered minerals (such as particle size, shape, surface texture, etc.), but also accurately measures the elemental composition of the mineral surface through energy dispersive spectroscopy (EDS). Through SEM analysis, we can observe the microstructure characteristics of iron oxides such as hematite and goethite in depth, and preliminarily determine their elemental composition, laying a foundation for further research.

[0042] Laser Raman Spectroscopy Analysis

[0043] Laser Raman spectroscopy technology is used to further verify the types of altered minerals. By measuring the Raman scattering spectrum of minerals under laser irradiation and comparing it with known standard spectrum, we can accurately identify the chemical composition and structural characteristics of the minerals. Laser Raman spectroscopy analysis has significant advantages in confirming the presence of iron oxides such as hematite and goethite, and can effectively exclude the interference of other similar minerals, ensuring the accuracy and reliability of the analysis results.

[0044] Electron Probe Micro-Analysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis

[0045] The application of electron probe analysis technology can accurately determine the content of major elements in altered minerals. By bombarding the surface of the mineral with a high-energy electron beam, characteristic X-ray spectra are generated, and their wavelengths and intensities are measured to determine the types and contents of elements. Meanwhile, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used to accurately determine the contents of trace and rare earth elements in altered minerals. The determination of major elements, trace elements, and rare earth elements is of great significance in revealing the genesis and evolution of altered minerals and providing valuable clues for subsequent prospecting work.

[0046] During EPMA analysis, special attention should be paid to the content changes of elements such as U, Mo, and W, which are closely related to uranium mineralization. By comparing and analyzing the content characteristics of these elements, we can further infer the possible sources of ore-forming materials and provide important evidence for revealing the genetic mechanism of uranium mineralization.

[0047] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is an advanced micro-in situ analysis technology with wide applications in geology, mineralogy, and geochemistry. This technology combines the high spatial resolution of laser ablation systems with the high sensitivity of inductively coupled plasma mass spectrometry (ICP-MS), enabling rapid and accurate analysis of trace elements in solid samples.

[0048] In the study of uranium deposits, LA-ICP-MS technology has shown its unique advantages. Through micro-in situ analysis of minerals in uranium deposits, the properties, sources, and evolution of ore-forming fluids can be revealed, providing important information for the study of ore genesis and metallogenic mechanisms.

[0049] Taking the Mianhuakeng uranium deposit in northern Guangdong as an example, researchers used LA-ICP-MS technology to analyze the trace elements and rare earth elements in iron oxides (hydroxides). During this process, the laser beam was precisely focused on a small area of the mineral sample, and the sample material was converted into aerosol through ablation, which was then introduced into the ICP-MS system for element analysis. This method not only enables quantitative detection of trace elements in minerals but also preserves the spatial distribution information of the sample, allowing researchers to accurately determine the occurrence state and distribution of elements.

[0050] In the study of the cotton pit uranium deposit, the application of LA-ICP-MS technology reveals the enrichment characteristics of trace elements such as U, Mo, W, Cu, Zn, and the distribution pattern of rare earth elements in iron oxides (hydroxides). These element information is of great significance to understanding the properties of ore-forming fluids, material sources and hydrothermal processes. For example, through LA-ICP-MS analysis, it is found that the hematite and goethite in the cotton pit uranium deposit are enriched in U, Mo, W and other elements, suggesting that the ore-forming material may mainly come from the surrounding granite. At the same time, the distribution pattern of rare earth elements also indicates the characteristics of CO32-rich ore-forming fluids.

[0051] In addition, LA-ICP-MS technology can also help researchers identify different forms of iron oxides (hydroxides) and explore their genesis and their indicative significance for uranium mineralization. For example, in the cotton pit uranium deposit, LA-ICP-MS analysis reveals the differences in element composition between disseminated hematite and euhedral-hedral hematite, indicating that they may have different origins and uranium enrichment mechanisms.

[0052] In summary, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) technology plays an important role in the study of uranium deposits. It not only provides accurate trace element and rare earth element data, but also preserves the spatial distribution information of the sample, providing strong support for the study of ore genesis and ore-forming mechanism. With the continuous development and improvement of technology, LA-ICP-MS technology will play an increasingly important role in future geological research.

[0053] In addition, we also need to pay attention to the distribution form of rare earth elements in altered minerals. Rare earth elements have unique geochemical properties, and their distribution form can reflect the properties and evolution of ore-forming fluids. By analyzing the distribution form of rare earth elements in altered minerals, we can further understand the temperature, oxygen fugacity, salinity and other parameters of ore-forming fluids, and provide key information for revealing the fluid source and evolution process of uranium mineralization.

[0054] (Four) Genetic analysis and prospecting indication

[0055] Genetic analysis of altered minerals

[0056] Based on the results of detailed mineralogical and geochemical analysis, combined with regional geological background and deposit geological characteristics, the genesis of altered minerals is analyzed in depth. Through analyzing the formation conditions, evolution process and paragenetic relationship with other minerals of altered minerals

[0057] Genetic analysis of altered minerals is a key step to understand the formation mechanism of uranium deposits and guide prospecting work. Based on the results of detailed mineralogical and geochemical analysis, we can further explore the genesis of altered minerals, which is specifically illustrated as follows.

[0058] Hematite genetic analysis:

[0059] Formation environment: Hematite formation is usually closely related to hydrothermal fluid activity. In granite-type uranium deposits, hematite may form during the oxidation of Fe2+ to Fe3+ in hydrothermal fluids, which often accompanies the reduction of U(VI) and the precipitation of uranium minerals.

[0060] Relationship between morphology and uranium mineralization: Euhedral-hedral hematite often contains uranium mineral inclusions, indicating its key role in the process of uranium mineralization. Disseminated hematite contains uranium in adsorption form, which may be related to the adsorption of uranium elements on the surface of hematite in the fluid.

[0061] Goethite genetic analysis:

[0062] Formation mechanism: The formation of goethite may be related to the leaching action of oxidizing groundwater. During groundwater flow, the oxygen in the fluid may react with the iron elements in the rock to form goethite.

[0063] Geochemical characteristics: The geochemical characteristics of goethite, especially its trace element and rare earth element content, can provide important information about the nature and evolution process of ore-forming fluids.

[0064] Genetic analysis of other altered minerals:

[0065] In addition to hematite and goethite, there may be other altered minerals in granite-type uranium deposits, such as purple-black fluorite, pyrite, microcrystalline quartz, chlorite, and calcite. The genesis and geochemical characteristics of these minerals are also important for understanding the formation mechanism of uranium deposits.

[0066] Comprehensive genetic analysis:

[0067] By comparing and analyzing the genetic characteristics of different altered minerals, we can further reveal the fluid source, evolution process, and ore-forming material source of uranium mineralization. These information is crucial for guiding prospecting work.

[0068] Prospecting indication and direction determination

[0069] Based on the results of genetic analysis and geochemical characteristics of altered minerals, we can further indicate the prospecting direction of uranium deposits.

[0070] Altered mineral enrichment area:

[0071] The enrichment area of altered minerals such as hematite and goethite is often a potential target area of uranium mineralization. These areas should be the focus of further exploration and verification.

[0072] Geochemical anomaly area:

[0073] By analyzing the elemental geochemical characteristics in altered minerals (such as the content changes of U, Mo, W, and other granite-related elements) and the distribution patterns of rare earth elements, we can identify geochemical anomaly areas. These areas may hide undiscovered uranium ore bodies.

[0074] Comprehensive prospecting strategy:

[0075] Combining regional geological structure, magmatic activity characteristics, and the genesis and geochemical characteristics of altered minerals, we can develop a comprehensive prospecting strategy. Through drilling verification, tunneling, and other means, we can further determine the specific location and size of the uranium ore body. The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be realized in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be considered as limiting the claims involved.

[0076] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for detecting and analyzing alteration minerals in granite-type uranium deposits, characterized in that, Includes the following steps: a. Collect altered rock or ore samples from granite-type uranium deposits; b. Pre-process the collected samples to prepare thin films and probe sheets; c. Use a polarizing microscope to conduct preliminary mineralogical observations on the prepared thin sections to determine the types, assemblages, and symbiotic relationships of altered minerals; d. Morphological analysis of altered minerals using scanning electron microscopy; e. Identification of the composition of altered minerals using laser Raman spectroscopy; f. Apply electron probe microanalysis to analyze the major element content of altered minerals; g. Use laser ablation inductively coupled plasma mass spectrometry to analyze the trace element and rare earth element content of altered minerals; h. Analyze the genesis of alteration minerals and their relationship with uranium mineralization to indicate the direction of uranium deposit exploration; The morphological characteristics of altered minerals were observed using scanning electron microscopy. Based on the results of laser Raman spectroscopy analysis, the main alteration minerals were identified, including hematite, goethite and magnetite. Analyze the geochemical characteristics of altered minerals of different forms, including major elements, trace elements and rare earth elements; Determine the properties of ore-forming fluids based on the rare earth element distribution patterns; By combining mineral assemblages and fluid conditions, the formation mechanism of altered minerals can be inferred; Different forms of hematite are used as prospecting indicators. Uranium in disseminated hematite exists in the form of adsorption, while uranium in euhedral to subhedral hematite exists in the form of uranium mineral micro-inclusions, thus indicating the potential and distribution characteristics of uranium mineralization.

2. The method for detecting and analyzing alteration minerals in granite-type uranium deposits according to claim 1, characterized in that, It also includes identifying U, Mo, and W granitic elements enriched in altered minerals based on the results of electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry, thereby inferring the origin of ore-forming materials.

3. The method for detecting and analyzing alteration minerals in granite-type uranium deposits according to claim 1, characterized in that, It also includes further distinguishing the morphology of hematite, identifying disseminated and euhedral-subhedral hematite.

4. A prospecting indicator method for granite-type uranium deposits, characterized in that, Different forms of hematite are used as prospecting indicators. Uranium in disseminated hematite exists in the form of adsorption, while uranium in euhedral to subhedral hematite exists in the form of uranium mineral micro-inclusions, thus indicating the potential and distribution characteristics of uranium mineralization.

5. The prospecting indication method for a granite-type uranium deposit according to claim 4, characterized in that, It also includes using the occurrence state and enrichment characteristics of uranium in altered minerals, combined with the regional geological background, to predict the size of uranium ore bodies.

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