A method for determining a carbonatite-type rare earth ore enrichment area

Abstract

The present application provides a kind of carbonatite type rare earth ore enrichment area determination method, in target exploration area, grid sampling point is laid, and three-dimensional space coordinate data of each sampling point is collected, etc.The average value is obtained by in-situ testing of multiple groups of mineral particles, and the deviation of LA-ICP-MS test data caused by uneven distribution of mineral micro-area elements is directly eliminated;The rare earth differentiation discriminant index is constructed to simultaneously couple the differentiation of light and heavy rare earths, the total amount of rare earths, the volatile fraction of fluorine and phosphorus mineralization, and the background fluctuation of regional lanthanum and ytterbium ratio;The rare earth enrichment coupling coefficient is combined with the logistic function to correct the regional rare earth background value, realize the quantitative coupling of the differentiation degree of rare earth and the total amount of rare earth, the four-level gradient unit is matched with 50m buffer zone smooth boundary, and the potential enrichment area with regular boundary and clear potential classification is directly output;Superimposed fracture, alkali rock contact zone vector layer is marked as first and second level target area, and high and low potential enrichment blocks are directly distinguished by relying on ore-controlling geological elements.

Description

Technical Field

[0001] This invention relates to the field of mineral geological exploration technology, and in particular to a method for determining the enrichment area of ​​carbonate rock-type rare earth minerals. Background Technology

[0002] Existing methods for identifying rare earth enrichment areas in carbonate rocks mostly rely on total rare earth content or the ratio of light to heavy rare earth elements for anomaly delineation. These methods can only characterize the enrichment degree of rare earth elements and cannot simultaneously couple key mineralizing volatile elements such as fluorine and phosphorus. At the same time, they ignore the interference of overall differentiation and fluctuation of the regional lanthanum-ytterbium ratio, which can easily lead to misclassification of mineralized anomaly areas as weakly altered carbonate rocks without mineralization or low-differentiation surrounding rocks. Traditional evaluation models lack standardized threshold calibration procedures, and the manual delineation of anomaly boundaries is highly subjective. The spatial grid generated by interpolation contains a large number of isolated noise points, and the quantitative coupling evaluation coefficient is not constructed in conjunction with the background value of total rare earth content, making it impossible to achieve gradient classification of enrichment degree. In addition, the conventional uniform grid sampling mode results in insufficient sampling density in the core area of ​​the rock mass and redundant sampling in the useless peripheral areas. The subsequent delineation of enrichment areas does not combine the classification of ore-controlling elements such as faults and alkaline rock contact zones. The final output target area lacks quantitative priority ranking basis, resulting in low accuracy of exploration target areas, high drilling engineering deployment costs, and large deviations in resource potential assessment. Summary of the Invention

[0003] In view of this, in order to solve the problems existing in the technical background, the present invention proposes a method for determining the enrichment area of ​​carbonate rock-type rare earth deposits. Specifically, it includes the following: A method for identifying rare earth enrichment areas in carbonate rock-type minerals involves setting up a grid of sampling points in the target exploration area, collecting carbonate rock cores or outcrop rock samples, conducting in-situ elemental analysis (LA-ICP-MS) on each sample to obtain the measured contents of total rare earth elements (R), light rare earth elements (L), heavy rare earth elements (H), fluorine (F), and phosphorus (P) for each sample, collecting the three-dimensional spatial coordinate data of each sampling point, importing all parameters into a spatial analysis module to construct a multi-parameter dataset, and calculating the rare earth differentiation discrimination index based on the dataset. Calculation formula: ; In the formula , , where are the lanthanum and ytterbium content of the i-th sample, respectively, and n is the total number of samples included in the statistics. The mean lanthanum-ytterbium ratio for the region was determined by selecting a dataset of mineral-free carbonate rock samples from the same region. benchmark threshold Extract the target area that meets the requirements > The sampling points form an initial set of outlier points. Distance-weighted interpolation is then used to perform spatial interpolation on these initial outlier points to obtain continuous two-dimensional surface data. Finally, a rare-earth enrichment coupling coefficient is constructed. Calculation formula: ; In the formula, k is the gradient adjustment coefficient. The background rare earth content of regional carbonate rocks, based on The numerical interval is divided into gradient units, and the closed regions connected by the same gradient unit in continuous space are defined as potential enrichment areas of carbonate rock-type rare earth minerals.

[0004] In some embodiments of the present invention, the grid sampling points are laid out using a variable spacing grid pattern. A 50m×50m dense grid is laid out within 300m of the boundary of the carbonate rock mass, a 150m×150m conventional grid is laid out in the 300m to 1000m range outside the rock mass, and a 300m×300m sparse grid is laid out in the area outside the rock mass beyond 1000m. During sampling, fresh, unweathered carbonate rock blocks are collected for each sample, and samples with an alteration degree higher than 45% are removed. Three groups of different mineral particles are selected for in-situ elemental testing of each sample, and the arithmetic mean is taken as the final elemental content data of the sample.

[0005] In some embodiments of the present invention, calculation benchmark threshold At that time, no fewer than 35 carbonate rock samples were selected from areas far from known mineralized zones, with alteration intensity below 15%, and without hydrothermal vein penetrations. All samples in this group were statistically analyzed. For numerical values, after removing discrete outliers using a box plot, the upper quartile is taken as the baseline threshold. .

[0006] In some embodiments of the present invention, the interpolation exponent of the weighted interpolation method is set to 2.2, the interpolation neighborhood search adopts an eight-neighborhood mode, the interpolation grid resolution is consistent with the minimum grid spacing of the field sampling, and after the interpolation is completed, a 3×3 mean filter is used to eliminate isolated noise grids generated by the interpolation.

[0007] In some embodiments of the present invention, the gradient adjustment coefficient k is set to a value range of 0.0002 to 0.0008. Using the median total rare earth element content of unmineralized carbonate rock samples, according to The values ​​are divided into four levels of gradient units from low to high, and the gradient unit boundaries are smoothed using a 50m buffer.

[0008] In some embodiments of the present invention, after delineating the potential enrichment zone, a spatial vector layer of regional fault structures and alkaline rock contact zones is superimposed. Closed areas located at the fault intersection and within 200m on both sides of the carbonate rock-alkaline rock contact zone are marked as primary enrichment target areas, and the remaining closed areas are marked as secondary enrichment target areas.

[0009] In some embodiments of the present invention, the raster unit within the primary enrichment target region is extracted. The mean, area, and average rock mass burial depth parameters are sorted according to the target area priority, and the resulting vector data file of the graded enrichment area is output.

[0010] The above technical solution has the following beneficial effects: This method uses variable-spacing grid sampling to match the mineralization development degree of different areas of the carbonate rock mass. In the mineralization core area, dense sampling is used to avoid missing small mineralization strips, while sparse sampling in the periphery directly reduces the number of field samples and testing costs. By averaging multiple sets of in-situ mineral particle tests, the bias in LA-ICP-MS test data caused by uneven element distribution in mineral micro-regions is directly eliminated. A rare earth differentiation discrimination index is constructed, synchronously coupling four key parameters: light and heavy rare earth differentiation, total rare earth content, fluorine and phosphorus mineralization volatiles, and regional lanthanum-ytterbium ratio background fluctuations, directly avoiding false anomalies caused by single-element index evaluation. The rare earth enrichment coupling coefficient, combined with a logistic function, corrects the regional rare earth background value, directly achieving quantitative coupling between the degree of rare earth differentiation and total rare earth content. A four-level gradient unit, paired with a 50m buffer zone, smooths the boundary, directly outputting potential enrichment areas with regular boundaries and clear potential classifications. Overlaying fault and alkaline rock contact zone vector layer mapping marks the first and second-level target areas, directly distinguishing high and low potential enrichment blocks based on ore-controlling geological elements. Extraction... The mean, area, and rock mass burial depth parameters complete the first-level target area quantitative sorting, and directly output graded vector results that can be used directly for drilling engineering deployment, without the need for manual secondary processing and evaluation of data. Attached Figure Description

[0011] Figure 1 This is a flowchart illustrating a method for determining the enrichment area of ​​carbonate rock-type rare earth minerals according to the present invention. Detailed Implementation

[0012] 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.

[0013] See Figure 1 The method for identifying rare earth enrichment areas in carbonate rock-type rare earth deposits is characterized by: setting up grid sampling points in the target exploration area, collecting carbonate rock cores or outcrop rock samples, conducting LA-ICP-MS in-situ elemental analysis on each sample to obtain the measured contents of total rare earth elements (R), light rare earth elements (L), heavy rare earth elements (H), fluorine (F), and phosphorus (P) in each sample, collecting three-dimensional spatial coordinate data of each sampling point, importing all parameters into a spatial analysis module to construct a multi-parameter dataset, and calculating the rare earth differentiation discrimination index based on the dataset. Calculation formula: ; In the formula , , where are the lanthanum and ytterbium content of the i-th sample, respectively, and n is the total number of samples included in the statistics. The mean lanthanum-ytterbium ratio for the region was determined by selecting a dataset of mineral-free carbonate rock samples from the same region. benchmark threshold Extract the target area that meets the requirements > The sampling points form an initial set of outlier points. Distance-weighted interpolation is then used to perform spatial interpolation on these initial outlier points to obtain continuous two-dimensional surface data. Finally, a rare-earth enrichment coupling coefficient is constructed. Calculation formula: ; In the formula, k is the gradient adjustment coefficient. The background rare earth content of regional carbonate rocks, based on The numerical interval is divided into gradient units, and the closed regions connected by the same gradient unit in continuous space are defined as potential enrichment areas of carbonate rock-type rare earth minerals.

[0014] Example 2, based on Example 1, uses a variable-spacing grid pattern for the grid sampling points. A 50m×50m dense grid is laid out within 300m of the carbonate rock mass boundary; a 150m×150m conventional grid is laid out between 300m and 1000m outside the rock mass; and a 300m×300m sparse grid is laid out beyond 1000m outside the rock mass. Fresh, unweathered carbonate rock blocks are collected for each sample, and samples with an alteration degree higher than 45% are discarded. Three groups of different mineral grains are selected for in-situ elemental analysis of each sample, and the arithmetic mean is taken as the final elemental content data for that sample. When calculating the baseline threshold, areas far from known mineralization and with high alteration intensity are selected within the region. At least 35 carbonate rock samples with a rare earth element content below 15% and no hydrothermal veins were collected. All values ​​of this group of samples were statistically analyzed. After removing discrete outliers using a box plot, the upper quartile was taken as the baseline threshold. The interpolation exponent of the weighted interpolation method was set to 2.2. The interpolation neighborhood search adopted an eight-neighborhood mode. The interpolation grid resolution was consistent with the minimum grid spacing of the field sampling. After interpolation, a 3×3 mean filter was used to eliminate isolated noise grids generated by interpolation. The gradient adjustment coefficient k was set to a value range of 0.0002 to 0.0008. The median of the total rare earth element content of the unmineralized carbonate rock samples was used to divide the samples into four levels of gradient units according to the values ​​from low to high. The gradient unit boundaries were smoothed using a 50m buffer.

[0015] Example 3, based on Example 1, in this example, after delineating the potential enrichment area, a spatial vector layer of regional fault structures and alkaline rock contact zone is superimposed. Closed areas located at the fault intersection and within 200m on both sides of the carbonate rock-alkaline rock contact zone are marked as primary enrichment target areas, and the remaining closed areas are marked as secondary enrichment target areas. The mean, area, and average rock mass burial depth parameters within the raster cells of the primary enrichment target areas are extracted. The target areas are prioritized according to the parameter sorting, and the graded enrichment area vector result file is output.

[0016] In this embodiment, a rare earth exploration area in a carbonate rock mass is selected as the target exploration area to carry out the complete enrichment zone determination operation and carry out the work of setting up sampling points with variable spacing grid. This step adopts the differentiated grid spacing to replace the traditional uniform grid layout mode. The working principle is that the rare earth mineralizing fluids in carbonate rock mainly migrate and enrich along the rock mass boundary and internal fractures. The 300m range of the rock mass boundary is the most concentrated area of ​​rare earth mineralization. Reducing the grid to 50m×50m for dense sampling can completely capture small-scale mineralization anomalies and avoid missing small enrichment bands by the sampling interval. The mineralization intensity of the transition zone from 300m to 1000m in the rock mass gradually decreases. Using a conventional 150m×150m grid reduces the amount of sampling work while controlling data accuracy. There is virtually no industrial mineralization potential beyond 1000m of the rock mass. The 300m×300m sparse grid is used only to construct the regional elemental background field, significantly reducing the manpower and material input for field sampling. Fresh, unweathered carbonate rock blocks are strictly selected during the sampling process, and samples with an alteration degree higher than 45% are removed. Weathering and strong alteration will cause leaching loss of rare earth, fluorine, and phosphorus elements, which will significantly interfere with the accuracy of subsequent elemental content measurements. Three independent mineral particles are selected for each sample to conduct in-situ elemental tests using LA-ICP-MS and the arithmetic mean is taken. Single mineral particle tests are easily affected by local mineral inclusions and micro-fracture fluids. The multi-particle mean can eliminate the test error caused by the uneven distribution of elements in the mineral micro-area. The five core indicators of total rare earth (R), light rare earth (L), heavy rare earth (H), fluorine (F), and phosphorus (P) are accurately obtained. The three-dimensional spatial coordinates of each sampling point are recorded simultaneously. The coordinates and elemental content data are uniformly entered into the spatial analysis module to construct a standardized multi-parameter dataset, completing the basic data collection and preprocessing.

[0017] Rare Earth Differentiation Discriminant Index Based on Multi-parameter Dataset Quantitative calculation, in the formula Quantifying the intensity of light and heavy rare earth element (LREE) differentiation, light LREE preferentially enriches during the mineralization process of carbonate rock-type rare earth deposits; higher values ​​for this logarithmic term indicate stronger mineralization differentiation. (Cube root term) The total rare earth element (REE) content is synchronously coupled with fluorine and phosphorus elements. Fluorine and phosphorus are key transport carriers for REE mineralization in carbonate rocks. Only when all three are in high synergy can mineralization potential be achieved. This avoids false anomalies caused by high total REE content without volatile distribution. The denominator introduces the absolute value of the regional lanthanum-ytterbium ratio dispersion deviation and adds a constant term of 0.01. Lanthanum represents light rare earth elements and ytterbium represents heavy rare earth elements. Fluctuations in the lanthanum-ytterbium ratio of regional samples can cause distortion in the differentiation evaluation. The absolute value of the deviation can offset the interference from the overall geological background of the region. The constant term of 0.01 is used to prevent the denominator value from being 0, which would cause calculation failure and ensure that the exponential solution can be completed for all samples. benchmark threshold The calibration process is objective and standardized, selecting no fewer than 35 non-mineralized carbonate rock samples that are far from mineralization, weak alteration, and without hydrothermal veins. These samples fully represent the non-mineralized geological background of the region. Box plots are used to eliminate discrete extreme values, thus removing abnormal values ​​caused by accidental alteration and small veins. The upper quartile is taken as the critical threshold for distinguishing between mineralization and non-mineralization, completely eliminating human interference. All sampling points are included. Numerical and Comparison, only retain > The points form an initial set of abnormal points, directly eliminating points with no mineral background, which greatly reduces the amount of data computation required for subsequent spatial interpolation.

[0018] Distance-weighted spatial interpolation and raster denoising are performed on the initial set of outlier points. The working principle of this step is that discrete sampling points cannot intuitively reflect the continuous spatial distribution of mineralization. Distance-weighted interpolation is based on the spatial element correlation theory. The interpolation power exponent of 2.2 is set to adapt to the gradual distribution characteristics of rare earth mineralization in carbonate rocks. The eight-neighbor search mode can capture the changing trend of elements in the surrounding points in all aspects compared with the four-neighbor search mode. The interpolation grid resolution matches the minimum 50m sampling grid in the field to ensure that spatial details are not lost. After the interpolation is completed, the generated two-dimensional raster will have isolated high-value noise points. These noise points are generated by local mineral micro-region anomalies and random test errors and have no actual mineralization significance. A 3×3 mean filter is used to smooth the raster and directly eliminate isolated noise raster, generating continuous rare earth differentiation index spatial surface data without abrupt distortion, providing a continuous spatial basis for subsequent enrichment gradient classification.

[0019] Calculation of rare earth enrichment coupling coefficient based on continuous two-dimensional surface data And divide into gradient units, As a quantitative classification index for enrichment potential, it relies on the S-shaped exponential function to correct rare earth background values. The denominator in the formula... For logistic functions, The median total rare earth element (REE) content in unmineralized carbonate rocks was selected to accurately represent the regional natural REE background. The gradient adjustment coefficient k was limited to the range of 0.0002–0.0008 to accommodate the REE content variation gradients in most carbonate rock REE deposits. When the total REE content R in the sample is significantly higher than the background value... When the denominator approaches 1, The numerical value is approximately equal to The evaluation weight of high rare earth enrichment areas is highlighted; when the total rare earth content is close to the background value, the denominator value is increased, reducing the coupling coefficient of low mineralization potential areas, realizing the two-way coupling evaluation of differentiation index and total rare earth content, and avoiding overestimation of the potential of low rare earth content areas by relying solely on differentiation index. according to The numerical values ​​are divided into four levels of gradient units from low to high. The four levels of gradients can intuitively distinguish four types of spatial regions: weak mineralization, medium mineralization, strong mineralization, and extremely rich mineralization. The boundaries of the gradient units are smoothed using a 50m buffer zone to eliminate the jagged boundaries caused by the interpolation grid. Closed grid areas that are interconnected within the same gradient unit are designated as potential enrichment areas of carbonate rock-type rare earth minerals, thus achieving quantitative spatial zoning of enrichment potential. For the delineated potential enrichment areas, target grading and marking are carried out, and two types of core ore-controlling vector maps are overlaid: regional fault structures and carbonate-alkaline rock contact zones. The working principle is that carbonate-type rare earth mineralizing fluids migrate along fault channels, and the degree of fluid convergence is the highest at the fault intersection. The contact zone between alkaline and carbonate rocks is an advantageous space for magma fluid exchange and rare earth element precipitation and enrichment. The 200m range on both sides of the contact zone is a favorable mineralization zone. Closed enrichment areas that fall within the fault intersection and the 200m range of the contact zone are designated as first-level enrichment target areas, representing the areas with the highest exploration potential. Other closed enrichment areas without structural support are marked as second-level enrichment target areas, realizing the structural constraint grading of the mineralization potential of enrichment areas and distinguishing high- and low-value exploration blocks.

[0020] Quantitative priority ranking is performed on the primary enriched target regions, and the results are output, extracting the content within each primary target region grid cell. Three quantitative parameters: mean, target area, and average burial depth of the rock mass. The mean value represents the overall rare earth enrichment intensity of the block, the area represents the scale of resource potential, and the depth of the rock mass directly determines the drilling construction cost. The order of target area exploration is formed by comprehensively ranking the three parameters, which directly guides the drilling project to prioritize the placement of high-enrichment, large-area, shallow-depth high-quality target areas, and finally outputs a vector result file of enrichment areas with graded and ranked attributes.

[0021] This invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the invention as claimed. The scope of protection of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for determining enrichment areas of carbonate rock-type rare earth deposits, characterized in that, The system deploys grid sampling points in the target exploration area, collects carbonate rock cores or outcrop rock samples, and conducts in-situ elemental analysis using LA-ICP-MS on each sample to obtain the measured contents of total rare earth elements (R), light rare earth elements (L), heavy rare earth elements (H), fluorine (F), and phosphorus (P). It also collects the three-dimensional spatial coordinate data of each sampling point, imports all parameters into the spatial analysis module to construct a multi-parameter dataset, and calculates the rare earth differentiation discriminant index based on the dataset. Calculation formula: ; In the formula , , where are the lanthanum and ytterbium content of the i-th sample, respectively, and n is the total number of samples included in the statistics. The mean lanthanum-ytterbium ratio for the region was determined by selecting a dataset of mineral-free carbonate rock samples from the same region. benchmark threshold Extract the target area that meets the requirements > The sampling points form an initial set of outlier points. Distance-weighted interpolation is then used to perform spatial interpolation on these initial outlier points to obtain continuous two-dimensional surface data. Finally, a rare-earth enrichment coupling coefficient is constructed. Calculation formula: ; In the formula, k is the gradient adjustment coefficient. The background rare earth content of regional carbonate rocks, based on The numerical interval is divided into gradient units, and the closed regions connected by the same gradient unit in continuous space are defined as potential enrichment areas of carbonate rock-type rare earth minerals.

2. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 1, characterized in that, The grid sampling points were laid out using a variable-spacing grid pattern. A 50m×50m dense grid was laid out within 300m of the boundary of the carbonate rock mass, a 150m×150m conventional grid was laid out in the 300m to 1000m range outside the rock mass, and a 300m×300m sparse grid was laid out in the area beyond 1000m outside the rock mass. During sampling, fresh, unweathered carbonate rock blocks were collected for each sample, and samples with an alteration degree higher than 45% were removed. Three groups of different mineral particles were selected for in-situ elemental analysis of each sample, and the arithmetic mean was taken as the final elemental content data of the sample.

3. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 1, characterized in that, calculate benchmark threshold At that time, no fewer than 35 carbonate rock samples were selected from areas far from known mineralized zones, with alteration intensity below 15%, and without hydrothermal vein penetrations. All samples in this group were statistically analyzed. For numerical values, after removing discrete outliers using a box plot, the upper quartile is taken as the baseline threshold. .

4. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 1, characterized in that, The interpolation exponent of the weighted interpolation method is set to 2.2, the interpolation neighborhood search adopts the eight-neighborhood mode, the interpolation grid resolution is consistent with the minimum grid spacing of the field sampling, and after the interpolation is completed, a 3×3 mean filter is used to eliminate isolated noise grids generated by the interpolation.

5. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 1, characterized in that, The gradient adjustment coefficient k is set to a value range of 0.0002 to 0.0008. Using the median total rare earth element content of unmineralized carbonate rock samples, according to The values ​​are divided into four levels of gradient units from low to high, and the gradient unit boundaries are smoothed using a 50m buffer.

6. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 1, characterized in that, After delineating the potential enrichment areas, a spatial vector layer of regional fault structures and alkaline rock contact zones is overlaid. Closed areas located at the fault intersections and within 200m on both sides of the carbonate rock-alkaline rock contact zone are marked as primary enrichment target areas, and the remaining closed areas are marked as secondary enrichment target areas.

7. The method for determining the enrichment area of ​​carbonate rock-type rare earth deposits according to claim 6, characterized in that, Extracting grid cells within the primary enrichment target region The mean, area, and average rock mass burial depth parameters are sorted according to the target area priority, and the resulting vector data file of the graded enrichment area is output.

Images