A Genetic Differentiation Method for Sedimentary Bauxite Based on Gallium / Lithium Element Allocation
By constructing a gallium-lithium elemental distribution model and combining it with multi-dimensional geochemical indicators, the problem of accuracy in identifying the genesis of sedimentary bauxite was solved, and efficient identification of genetic types and study of mineralization regularities were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GEOLOGICAL SURVEY INST OF GUANGXI ZHUANG AUTONOMOUS REGION
- Filing Date
- 2026-05-27
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies are insufficient to accurately determine the genetic type of sedimentary bauxite. Traditional methods are prone to misjudgment, single-element tracing is difficult to simultaneously respond to information on transport processes and subsequent fluid alteration, and there is a lack of systematic quantitative models for gallium and lithium elemental distribution.
By collecting samples and performing X-ray fluorescence spectroscopy, inductively coupled plasma mass spectrometry, and multi-collector plasma mass spectrometry, the gallium-titanium ratio and chemical alteration index were calculated. Combined with the lithium content and lithium isotope ratio, a gallium-lithium partition coupling model was constructed, and the genetic type was determined using cluster analysis and discriminant analysis algorithms.
It has achieved high accuracy in identifying the genesis of sedimentary bauxite, refined the tracing of provenance and sedimentary environment, and improved the scientific nature of mineralization research and the efficiency of mineral exploration.
Smart Images
Figure CN122306857A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of genetic identification technology, specifically to a method for identifying the genesis of sedimentary bauxite based on gallium / lithium elemental distribution. Background Technology
[0002] Accurate identification of bauxite genetic types plays a crucial supporting role in the study of mineralization regularity and the deployment of exploration projects. The mineralization process of sedimentary bauxite involves a multi-stage evolution of weathering and erosion in the source area, clastic transport and deposition, and subsequent diagenetic leaching and alteration. Different genetic subtypes differ significantly in spatial distribution and ore quality. However, current identification techniques still have obvious limitations. Traditional methods mainly rely on three approaches: First, macro-geological identification, which is based on the contact relationship between the deposit and the basement and the sequence stratigraphy. However, after strong surface leaching, the original structure is often destroyed, which can easily lead to misjudgment of in-situ sedimentary and modified deposits. Second, single-element geochemical tracing, which usually selects inert elements such as chromium and zirconium to constrain the source area attributes. However, a single indicator is difficult to respond simultaneously to the transport process and the information of subsequent fluid modification, and often presents multiple interpretations. Third, mineral typological identification, which uses heavy mineral assemblage or the degree of order of clay minerals to assist in the determination. However, the mineral composition of sedimentary bauxite tends to be homogeneous, and there is a significant convergence phenomenon between different genetic types. Existing technologies place the inert source tracing of gallium and the active fluid response of lithium in a separate framework, and a systematic quantitative model of the bi-element partition coupling has not yet been established. Therefore, it is urgent to develop a discrimination method that integrates the complementary properties of gallium and lithium in order to overcome the current technical bottleneck. Summary of the Invention
[0003] The purpose of this invention is to provide a method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution, so as to solve the problems mentioned in the background art.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution, comprising the following steps: S1. For the three types of deposits—alien weathering type, in-situ sedimentary type, and sedimentary-leaching alteration type—samples are collected systematically along the complete vertical profile of the aluminum-bearing rock system. The original samples are coarsely crushed and finely ground to 200 mesh, then homogenized and divided into two portions, A and B, for chemical testing of major and trace elements and analysis of mineral phases and isotopes, respectively. S2. Using X-ray fluorescence spectroscopy, inductively coupled plasma mass spectrometry and multi-collector plasma mass spectrometry, the major elements, gallium-lithium trace elements and lithium isotope ratios of the samples were determined, the chemical alteration index was quantitatively calculated, the element occurrence state was identified, and a geochemical original database was established. S3. The source properties and weathering degree are determined by combining the gallium-titanium ratio and chemical alteration index. The sedimentary facies and transportation process are inverted by lithium content and lithium isotope ratio. Based on this, a three-stage gallium-lithium partition coupling model of source preparation, transportation and sedimentation, and diagenetic modification is constructed to restore the element migration path of the entire mineralization process. S4. Based on clustering and discriminant analysis of known genetic samples, solidify the quantitative threshold system of multiple indicators such as gallium content, gallium-titanium ratio, lithium content and lithium isotopes for the three types of mineral deposits. After verification and iterative optimization until the accuracy meets the standard, output the discriminant chart and quantitative standard table.
[0005] Preferably, step S1 specifically includes the following steps: S101. Based on the existing geological exploration data of bauxite deposits in the study area, sampling points were set up for three types of deposits: allochthonous weathering type, in-situ sedimentary type, and sedimentary-leaching alteration type. The sampling followed the principle of complete vertical profile control of the bauxite strata. The sampling sequence started from the top surface of the paleoweathering crust of the underlying carbonate basement and continued upward to collect iron-bearing claystone section, dense massive industrial bauxite layer, bauxite mudstone interlayer, and up to the bottom boundary of the overlying carbonaceous mudstone. The mass of each sample was greater than or equal to 500 grams. The structural type, stratigraphic elevation, and lithological interface transition characteristics of the samples were measured and recorded simultaneously. S102. The collected sample is fed into a jaw crusher for coarse crushing. The output particle size is controlled to be 1 cm to 2 cm. After the coarse crushed product is divided and homogenized once by a divider, it is transferred to an agate ball mill for fine grinding. During the fine grinding process, the speed and running time of the mill are controlled until all the obtained powder material passes the 200 target accuracy, that is, the particle size is less than 74 micrometers. S103. After the finely ground material is dried in an oven at 105℃ for 2 hours, it undergoes three tumbling mixing and two reduction operations to finally obtain a homogenized powder sample, which is then divided into two portions, A and B. Sample A is designated for X-ray fluorescence spectrometry major element determination and inductively coupled plasma mass spectrometry trace element analysis, while sample B is designated for X-ray diffraction mineral phase identification, scanning electron microscopy-energy dispersive spectroscopy micro-area composition analysis, and multi-receiver inductively coupled plasma mass spectrometry lithium isotope ratio determination.
[0006] Preferably, step S2 specifically includes the following steps: S201, Take The sample powder was analyzed using X-ray fluorescence spectrometry to determine its major components, including the contents of aluminum oxide, titanium dioxide, silicon dioxide, calcium oxide, sodium oxide, and potassium oxide. The results were expressed as a percentage by mass of oxides. Simultaneous sampling was also performed. After the sample powder was digested by acid dissolution, the contents of gallium and lithium were accurately determined by inductively coupled plasma mass spectrometry (ICP-MS). During the instrumental analysis, the detection limit for gallium was required to be no greater than 0.1 × 10⁻⁻⁻⁶. 6The detection limit for lithium is no greater than 1.0 × 10⁻ 6 This is to capture subtle geochemical fluctuation signals in the sample during the mineralization process; S202. Based on the major component data measured by X-ray fluorescence spectrometer, each major component is converted to generate a mole fraction. This mole fraction is then substituted into the chemical alteration index formula to perform the calculation, thereby determining the chemical alteration index value that characterizes the weathering intensity. S203, Take High-precision determination of lithium isotope ratios was performed on sample powder using a multi-receiver inductively coupled plasma mass spectrometer. During the testing process, the mass fractionation effect of the instrument was monitored throughout using a standard-sample-standard cross-validation method to ensure accurate measurements. The value analysis error was controlled within an extremely low range, thus providing high-resolution isotopic evidence for subsequent determination of sedimentary facies zone assignment and redox conditions.
[0007] Preferably, step S2 further includes the following steps: S204, combined application of X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy system to... The samples were subjected to phase identification and micro-area composition analysis. The X-ray diffractometer was used to determine the main phase composition of the samples, and the scanning electron microscope-energy dispersive spectroscopy system was used to observe the microstructure of the target minerals and label the elemental distribution. The focus was on identifying and confirming the occurrence state of gallium in the diaspore lattice in which it replaces aluminum atoms in a isomorphous manner, and the specific form of lithium in the interlayer structure of illite and kaolinite clay minerals through ion adsorption. S205. After all test data is archived in a unified manner, it is stored in the database.
[0008] Preferably, step S3 specifically includes the following steps: S301. Extract the measured gallium content data, combine it with the titanium dioxide content measurement results, calculate the gallium-titanium ratio parameter using the gallium content and titanium dioxide content, simultaneously extract the chemical alteration index value, and calculate the ratio parameter of the gallium content to the chemical alteration index value, using it as the gallium weathering ratio index. S302. When the gallium-to-titanium ratio of a sample is greater than 0.5 and the chemical alteration index is less than 80, its source is determined to be island arc acidic volcanic ash. When the gallium-to-titanium ratio of a sample is less than 0.2 and the coefficient of variation of gallium content in the vertical profile of the sample is greater than 30%, its source is determined to be magmatic mixed source.
[0009] Preferably, step S3 further includes the following steps: S303. After comprehensively reviewing the measured absolute lithium content data, the lithium occurrence state confirmed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) system, and the lithium isotope ratio data measured using a multi-receiver inductively coupled plasma mass spectrometer (ICP-MS), a determination is made: when the lithium content is greater than 500 × 10⁻⁻⁶… 6 And δ 7 When the Li value is positive, the depositional environment is determined to be a terrestrial freshwater sedimentary system. When the lithium content and δ... 7 When the Li value falls between the characteristic values of terrestrial and marine facies, the sedimentary environment is determined to be a transitional marine-terrestrial sedimentary system; when the lithium content is relatively depleted and δ... 7 When the Li value is negative, the depositional environment is determined to be a marine sedimentary system; S304. Based on the source identification and sedimentary environment inversion results, a three-stage gallium-lithium partition coupling evolution model of mineralization was established. This three-stage partition coupling model restored the element migration path of bauxite from the weathering of the parent rock, transportation and deposition to the later transformation. S305. Test data from three types of bauxite deposits within the study area—exothermic, in-situ sedimentary, and sedimentary-leaching altered—with high levels of geological exploration and clearly defined genetic types based on geological evidence, were selected as training samples. The measured gallium and lithium contents, the calculated gallium-to-titanium ratio, and the measured δ0... 7 Using Li value as the input variable, cluster analysis algorithm was employed to identify the natural aggregation characteristics of the three types of mineral deposit samples in the multidimensional geochemical parameter space. Discriminant analysis algorithm was then used to solve the optimal classification interface equation between each category, determining the optimal classification interface equation for the three types of mineral deposits based on gallium content, lithium content, gallium-titanium ratio, and δ. 7 Quantitative distribution boundary in a multidimensional parameter space formed by Li values.
[0010] Preferably, step S4 specifically includes the following steps: S401. For weathered bauxite deposits from other locations, the discrimination threshold condition is set as gallium content greater than 30 × 10⁻⁻⁶. 6 The gallium-to-titanium ratio is greater than 0.6, and the lithium content is less than 200 × 10⁻ 6 ; S402. For in-situ sedimentary bauxite, the discrimination threshold condition is set as gallium content between 15 × 10⁻⁻⁶. 6 Up to 30×10⁻ 6 The gallium-to-titanium ratio is between 0.2 and 0.5, and the lithium content is between 500 × 10⁻⁻⁻⁶. 6 Up to 2000×10⁻ 6 Between, and δ 7 The Li value is between 0‰ and 1‰; S403. For sediment-leaching modified bauxite, the discrimination threshold condition is set as gallium content between 10 × 10⁻⁻⁶. 6 Up to 25×10⁻ 6 Between these values, the gallium-to-titanium ratio is less than 0.3, and the lithium content is less than 300 × 10⁻ 6 And the chemical alteration index value is greater than 95; S404. Collect several bauxite samples of unknown origin from the study area as a verification sample set, perform all testing and analysis procedures on the verification samples, and obtain the geochemical parameters of each verification sample.
[0011] Preferably, step S4 further includes the following steps: S405. Substitute the geochemical parameters of the verification sample into the solidified threshold standard system to determine the genetic type, and compare the determination results with the actual genesis confirmed by detailed geological exploration to calculate the discrimination accuracy. S406. Set the model solidification qualification standard as a discrimination accuracy of not less than 90%. When the discrimination accuracy of the first verification meets the qualification standard, the discrimination model is directly solidified. When the discrimination accuracy is less than 90%, the batch of verification samples is added to the training sample database, and cluster analysis and discriminant analysis are re-executed to correct the distribution boundaries between each category. Iterative optimization is carried out until the discrimination accuracy meets the qualification standard. S407. Based on the classification interface equation and threshold parameters in the solidified model, compile a gallium-lithium dual-element collaborative discrimination chart. This chart uses the gallium-titanium ratio as the x-axis and the lithium content as the y-axis, and labels δ. 7 Contour lines for Li values are used to divide the region into zones. A quantitative standard table of regional genetic types is compiled simultaneously. This table lists the numerical ranges and judgment priorities of the three types of deposits on each discrimination index. The map and standard table are output as standardized results.
[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention establishes a multi-dimensional geochemical index system, including gallium-titanium ratio, gallium weathering ratio, and lithium content, which solidifies the exclusive quantitative threshold standards for three types of mineral deposits: allochthonous weathering type, in-situ sedimentary type, and sedimentary-leaching type. The system has a high accuracy rate and effectively solves the technical problems of unclear genetic types, multiple solutions, and high misjudgment rate caused by traditional methods that rely on field macroscopic observation and subjective experience judgment. 2. This invention fully utilizes the strong aluminum affinity and inert tracer properties of gallium and the active tracer properties of lithium, which are easy to migrate and adsorb, to construct a three-stage gallium-lithium partition coupling evolution model, which includes the source preparation period, transportation and deposition period, and diagenetic modification period. This model can not only trace the source of island arc acidic volcanic ash and magmatic rock mixtures in detail with gallium-titanium ratio and chemical alteration index, and quantitatively characterize the weathering intensity, but also accurately invert the terrestrial, marine-terrestrial transitional and marine sedimentary environments with lithium isotopes and occurrence states, thus realizing the dynamic reconstruction of the entire chain of bauxite mineralization process from parent rock weathering and erosion, clastic transportation and deposition to later surface leaching modification. 3. Based on cluster analysis and discriminant analysis algorithms, this invention solves the optimal classification interface in a multi-dimensional parameter space, and compiles a gallium-lithium dual-element collaborative discriminant chart and a regional-specific genetic type quantitative standard table, which significantly improves the scientific nature of bauxite mineralization regularity research and the efficiency of mineral exploration. Attached Figure Description
[0013] Figure 1 An overall method flowchart is provided for embodiments of the present invention. Detailed Implementation
[0014] 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.
[0015] Example 1: Please see Figure 1 This invention provides a technical solution: a method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution, comprising the following steps: S1. For the three types of deposits—alien weathering type, in-situ sedimentary type, and sedimentary-leaching alteration type—samples are collected systematically along the complete vertical profile of the aluminum-bearing rock system. The original samples are coarsely crushed and finely ground to 200 mesh, then homogenized and divided into two portions, A and B, for chemical testing of major and trace elements and analysis of mineral phases and isotopes, respectively. S2. Using X-ray fluorescence spectroscopy, inductively coupled plasma mass spectrometry and multi-collector plasma mass spectrometry, the major elements, gallium-lithium trace elements and lithium isotope ratios of the samples were determined, the chemical alteration index was quantitatively calculated, the element occurrence state was identified, and a geochemical original database was established. S3. The source properties and weathering degree are determined by combining the gallium-titanium ratio and chemical alteration index. The sedimentary facies and transportation process are inverted by lithium content and lithium isotope ratio. Based on this, a three-stage gallium-lithium partition coupling model of source preparation, transportation and sedimentation, and diagenetic modification is constructed to restore the element migration path of the entire mineralization process. S4. Based on clustering and discriminant analysis of known genetic samples, solidify the quantitative threshold system of multiple indicators such as gallium content, gallium-titanium ratio, lithium content and lithium isotopes for the three types of mineral deposits. After verification and iterative optimization until the accuracy meets the standard, output the discriminant chart and quantitative standard table.
[0016] S1 specifically includes the following steps: S101. Based on the existing geological exploration data of bauxite deposits in the study area, sampling points were set up for three types of deposits: allochthonous weathering type, in-situ sedimentary type, and sedimentary-leaching alteration type. The sampling followed the principle of complete vertical profile control of the bauxite strata. The sampling sequence started from the top surface of the paleoweathering crust of the underlying carbonate basement and continued upward to collect iron-bearing claystone section, dense massive industrial bauxite layer, bauxite mudstone interlayer, and up to the bottom boundary of the overlying carbonaceous mudstone. The mass of each sample was greater than or equal to 500 grams. The structural type, stratigraphic elevation, and lithological interface transition characteristics of the samples were measured and recorded simultaneously. S102. The collected sample is fed into a jaw crusher for coarse crushing. The output particle size is controlled to be 1 cm to 2 cm. After the coarse crushed product is divided and homogenized once by a divider, it is transferred to an agate ball mill for fine grinding. During the fine grinding process, the speed and running time of the mill are controlled until all the obtained powder material passes the 200 target accuracy, that is, the particle size is less than 74 micrometers. S103. After the finely ground material is dried in an oven at 105℃ for 2 hours, it is subjected to three tumbling and mixing operations and two reduction operations to finally obtain a homogenized powder sample, which is then divided into two portions, A and B. Sample A is designated for X-ray fluorescence spectrometry major element determination and inductively coupled plasma mass spectrometry trace element analysis, while sample B is designated for X-ray diffraction mineral phase identification, scanning electron microscopy-energy dispersive spectroscopy micro-area composition analysis, and multi-collector inductively coupled plasma mass spectrometry lithium isotope ratio determination. S2 specifically includes the following steps: S201, Take The sample powder was analyzed using X-ray fluorescence spectrometry to determine its major components, including the contents of aluminum oxide, titanium dioxide, silicon dioxide, calcium oxide, sodium oxide, and potassium oxide. The results were expressed as a percentage by mass of oxides. Simultaneous sampling was also performed. After the sample powder was digested by acid dissolution, the contents of gallium and lithium were accurately determined by inductively coupled plasma mass spectrometry (ICP-MS). During the instrumental analysis, the detection limit for gallium was required to be no greater than 0.1 × 10⁻⁻⁻⁶. 6 The detection limit for lithium is no greater than 1.0 × 10⁻ 6 This is to capture subtle geochemical fluctuation signals in the sample during the mineralization process; S202. Based on the major component data measured by X-ray fluorescence spectrometer, each major component is converted to generate a mole fraction. This mole fraction is then substituted into the chemical alteration index formula to perform the calculation, thereby determining the chemical alteration index value that characterizes the weathering intensity. The specific formula for the chemical alteration index is as follows: in, This indicates the total amount of aluminum oxide in the sample. This indicates the calcium oxide content present in silicate mineral phases. This indicates the total amount of sodium oxides in the sample. This indicates the total amount of potassium oxides in the sample. Indicates the chemical alteration index value; S203, Take High-precision determination of lithium isotope ratios was performed on sample powder using a multi-receiver inductively coupled plasma mass spectrometer. During the testing process, the mass fractionation effect of the instrument was monitored throughout using a standard-sample-standard cross-validation method to ensure accurate measurements. The value analysis error was controlled within an extremely low range, thus providing high-resolution isotopic evidence for subsequent determination of sedimentary facies zone assignment and redox conditions; S2 also includes the following steps: S204, combined application of X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy system to... The samples were subjected to phase identification and micro-area composition analysis. X-ray diffraction was used to determine the main phase composition of the samples, and scanning electron microscopy-energy dispersive spectroscopy system was used to observe the microstructure of the target minerals and label the elemental distribution. The focus was on identifying and confirming the occurrence state of gallium in the diaspore lattice in which it replaces aluminum atoms in a isomorphous manner, and the specific form of lithium in the interlayer structure of illite and kaolinite clay minerals through ion adsorption. S205. After all test data is archived in a unified manner, it is stored in the database; S3 specifically includes the following steps: S301. Extract the measured gallium content data, combine it with the titanium dioxide content measurement results, calculate the gallium-titanium ratio parameter using the gallium content and titanium dioxide content, simultaneously extract the chemical alteration index value, and calculate the ratio parameter of the gallium content to the chemical alteration index value, using it as the gallium weathering ratio index. S302. When the gallium-to-titanium ratio of a sample is greater than 0.5 and the chemical alteration index is less than 80, its source is determined to be island arc acidic volcanic ash. When the gallium-to-titanium ratio of a sample is less than 0.2 and the coefficient of variation of gallium content in the vertical profile of the sample is greater than 30%, its source is determined to be magmatic mixed source. S3 also includes the following steps: S303. After comprehensively reviewing the measured absolute lithium content data, the lithium occurrence state confirmed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) system, and the lithium isotope ratio data measured using a multi-receiver inductively coupled plasma mass spectrometer (ICP-MS), a determination is made: when the lithium content is greater than 500 × 10⁻⁻⁶… 6 And δ 7 When the Li value is positive, the depositional environment is determined to be a terrestrial freshwater sedimentary system. When the lithium content and δ... 7 When the Li value falls between the characteristic values of terrestrial and marine facies, the sedimentary environment is determined to be a transitional marine-terrestrial sedimentary system; when the lithium content is relatively depleted and δ... 7 When the Li value is negative, the depositional environment is determined to be a marine sedimentary system; S304. Based on the source identification and sedimentary environment inversion results, a three-stage gallium-lithium partition coupling evolution model of mineralization was established. This three-stage partition coupling model restored the element migration path of bauxite from the weathering of the parent rock, transportation and deposition to the later transformation. The three stages are as follows: S3041. During the source preparation phase of Stage 1, the gallium content in the model exhibits an abnormal enrichment characteristic, with an absolute content greater than 30 × 10⁻⁻⁴. 6 The gallium-to-titanium ratio is high, and the chemical activity of lithium is low at this stage. Its content and isotopic characteristics mainly reflect the inheritance information of the parent rock. S3042. During the second stage of transport and deposition, the lithium content in the model shows a sharp increasing trend, with an absolute content greater than 500 × 10⁻⁻⁶. 6 δ 7 The positive shift in Li value indicates that lithium carried by terrigenous clastic material undergoes large-scale adsorption and enrichment with clay minerals within the basin. S3043. During the stage 3 lithological alteration period, the gallium weathering ratio in the model tends to stabilize, reflecting the weathering resistance and retention characteristics of inert gallium, while the lithium content decreases significantly due to surface leaching. δ 7 The Li value shifts systematically with the change in alteration intensity; S305. Test data from three types of bauxite deposits within the study area—exothermic, in-situ sedimentary, and sedimentary-leaching altered—with high levels of geological exploration and clearly defined genetic types based on geological evidence, were selected as training samples. The measured gallium and lithium contents, the calculated gallium-to-titanium ratio, and the measured δ0... 7 Using Li value as the input variable, cluster analysis algorithm was employed to identify the natural aggregation characteristics of the three types of mineral deposit samples in the multidimensional geochemical parameter space. Discriminant analysis algorithm was then used to solve the optimal classification interface equation between each category, determining the optimal classification interface equation for the three types of mineral deposits based on gallium content, lithium content, gallium-titanium ratio, and δ.7 Quantitative distribution boundary in a multidimensional parameter space composed of Li values; S4 specifically includes the following steps: S401. For weathered bauxite deposits from other locations, the discrimination threshold condition is set as gallium content greater than 30 × 10⁻⁻⁶. 6 The gallium-to-titanium ratio is greater than 0.6, and the lithium content is less than 200 × 10⁻ 6 ; S402. For in-situ sedimentary bauxite, the discrimination threshold condition is set as gallium content between 15 × 10⁻⁻⁶. 6 Up to 30×10⁻ 6 The gallium-to-titanium ratio is between 0.2 and 0.5, and the lithium content is between 500 × 10⁻⁻⁻⁶. 6 Up to 2000×10⁻ 6 Between, and δ 7 The Li value is between 0‰ and 1‰; S403. For sediment-leaching modified bauxite, the discrimination threshold condition is set as gallium content between 10 × 10⁻⁻⁶. 6 Up to 25×10⁻ 6 Between these values, the gallium-to-titanium ratio is less than 0.3, and the lithium content is less than 300 × 10⁻ 6 And the chemical alteration index value is greater than 95; S404. Collect several bauxite samples of unknown origin from the study area as a verification sample set, perform all testing and analysis procedures on the verification samples, and obtain the geochemical parameters of each verification sample. S4 also includes the following steps: S405. Substitute the geochemical parameters of the verification sample into the solidified threshold standard system to determine the genetic type, and compare the determination results with the actual genesis confirmed by detailed geological exploration to calculate the discrimination accuracy. S406. Set the model solidification qualification standard as a discrimination accuracy of not less than 90%. When the discrimination accuracy of the first verification meets the qualification standard, the discrimination model is directly solidified. When the discrimination accuracy is less than 90%, the batch of verification samples is added to the training sample database, and cluster analysis and discriminant analysis are re-executed to correct the distribution boundaries between each category. Iterative optimization is carried out until the discrimination accuracy meets the qualification standard. S407. Based on the classification interface equation and threshold parameters in the solidified model, compile a gallium-lithium dual-element collaborative discrimination chart. This chart uses the gallium-titanium ratio as the x-axis and the lithium content as the y-axis, and labels δ. 7 Contour lines for Li values are used to divide the region into zones. A quantitative standard table of regional genetic types is compiled simultaneously. This table lists the numerical ranges and judgment priorities of the three types of deposits on each discrimination index. The map and standard table are output as standardized results.
[0017] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0018] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution, characterized in that, The method includes the following steps: S1. For the three types of deposits, namely, allochthonous weathering type, in-situ sedimentary type and sedimentary-leaching type, samples are collected from the complete vertical profile system exposed along the aluminum-bearing rock system. The original samples are coarsely crushed and finely ground to 200 mesh and then homogenized and divided into two parts, A and B, for chemical testing of major and trace elements and analysis of mineral phases and isotopes, respectively. S2. Using X-ray fluorescence spectroscopy, inductively coupled plasma mass spectrometry and multi-collector plasma mass spectrometry, the major elements, gallium-lithium trace elements and lithium isotope ratios of the samples were determined, the chemical alteration index was quantitatively calculated, the element occurrence state was identified, and a geochemical original database was established. S3. The source properties and weathering degree are determined by combining the gallium-titanium ratio and chemical alteration index. The sedimentary facies and transportation process are inverted by lithium content and lithium isotope ratio. Based on this, a three-stage gallium-lithium partition coupling model of source preparation, transportation and sedimentation, and diagenetic modification is constructed to restore the element migration path of the entire mineralization process. S4. Based on clustering and discriminant analysis of known genetic samples, solidify the quantitative threshold system of multiple indicators such as gallium content, gallium-titanium ratio, lithium content and lithium isotopes for the three types of mineral deposits. After verification and iterative optimization until the accuracy meets the standard, output the discriminant chart and quantitative standard table.
2. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 1, characterized in that, S1 specifically includes the following steps: S101. Based on the existing geological exploration data of bauxite deposits in the study area, sampling points were set up for three types of deposits: allochthonous weathering type, in-situ sedimentary type, and sedimentary-leaching alteration type. The sampling followed the principle of complete vertical profile control of the bauxite strata. The sampling sequence started from the top surface of the paleoweathering crust of the underlying carbonate basement and continued upward to collect iron-bearing claystone section, dense massive industrial bauxite layer, bauxite mudstone interlayer, and up to the bottom boundary of the overlying carbonaceous mudstone. The mass of each sample was greater than or equal to 500 grams. The structural type, stratigraphic elevation, and lithological interface transition characteristics of the samples were measured and recorded simultaneously. S102. The collected sample is fed into a jaw crusher for coarse crushing. The output particle size is controlled to be 1 cm to 2 cm. After the coarse crushed product is divided and homogenized once by a divider, it is transferred to an agate ball mill for fine grinding. During the fine grinding process, the speed and running time of the mill are controlled until all the obtained powder material passes the 200 target accuracy, that is, the particle size is less than 74 micrometers. S103. After the finely ground material is dried in an oven at 105℃ for 2 hours, it undergoes three tumbling mixing and two reduction operations to finally obtain a homogenized powder sample, which is then divided into two portions, A and B. Sample A is designated for X-ray fluorescence spectrometry major element determination and inductively coupled plasma mass spectrometry trace element analysis, while sample B is designated for X-ray diffraction mineral phase identification, scanning electron microscopy-energy dispersive spectroscopy micro-area composition analysis, and multi-receiver inductively coupled plasma mass spectrometry lithium isotope ratio determination.
3. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 1, characterized in that, S2 specifically includes the following steps: S201, Take The sample powder was analyzed using X-ray fluorescence spectrometry to determine its major components, including the contents of aluminum oxide, titanium dioxide, silicon dioxide, calcium oxide, sodium oxide, and potassium oxide. The results were expressed as a percentage by mass of oxides. Simultaneous sampling was also performed. After the sample powder was digested by acid dissolution, the contents of gallium and lithium were accurately determined by inductively coupled plasma mass spectrometry (ICP-MS). During the instrumental analysis, the detection limit for gallium was required to be no greater than 0.1 × 10⁻⁻⁻⁶. 6 The detection limit for lithium is no greater than 1.0 × 10⁻ 6 This is to capture subtle geochemical fluctuation signals in the sample during the mineralization process; S202. Based on the major component data measured by X-ray fluorescence spectrometer, each major component is converted to generate a mole fraction. This mole fraction is then substituted into the chemical alteration index formula to perform the calculation, thereby determining the chemical alteration index value that characterizes the weathering intensity. S203, Take High-precision determination of lithium isotope ratios was performed on sample powder using a multi-receiver inductively coupled plasma mass spectrometer. During the testing process, the mass fractionation effect of the instrument was monitored throughout using a standard-sample-standard cross-validation method to ensure accurate measurements. The value analysis error was controlled within an extremely low range, thus providing high-resolution isotopic evidence for subsequent determination of sedimentary facies zone assignment and redox conditions.
4. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 3, characterized in that, S2 further includes the following steps: S204, combined application of X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy system to... The samples were subjected to phase identification and micro-area composition analysis. The X-ray diffractometer was used to determine the main phase composition of the samples, and the scanning electron microscope-energy dispersive spectroscopy system was used to observe the microstructure of the target minerals and label the elemental distribution. The focus was on identifying and confirming the occurrence state of gallium in the diaspore lattice in which it replaces aluminum atoms in a isomorphous manner, and the specific form of lithium in the interlayer structure of illite and kaolinite clay minerals through ion adsorption. S205. After all test data is archived in a unified manner, it is stored in the database.
5. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 1, characterized in that, S3 specifically includes the following steps: S301. Extract the measured gallium content data, combine it with the titanium dioxide content measurement results, calculate the gallium-titanium ratio parameter using the gallium content and titanium dioxide content, simultaneously extract the chemical alteration index value, and calculate the ratio parameter of the gallium content to the chemical alteration index value, using it as the gallium weathering ratio index. S302. When the gallium-to-titanium ratio of a sample is greater than 0.5 and the chemical alteration index is less than 80, its source is determined to be island arc acidic volcanic ash. When the gallium-to-titanium ratio of a sample is less than 0.2 and the coefficient of variation of gallium content in the vertical profile of the sample is greater than 30%, its source is determined to be magmatic mixed source.
6. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 5, characterized in that, S3 specifically includes the following steps: S303. After comprehensively reviewing the measured absolute lithium content data, the lithium occurrence state confirmed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) system, and the lithium isotope ratio data measured using a multi-receiver inductively coupled plasma mass spectrometer (ICP-MS), a determination is made: when the lithium content is greater than 500 × 10⁻⁻⁶… 6 And δ 7 When the Li value is positive, the depositional environment is determined to be a terrestrial freshwater sedimentary system. When the lithium content and δ... 7 When the Li value falls between the characteristic values of terrestrial and marine facies, the sedimentary environment is determined to be a transitional marine-terrestrial sedimentary system; when the lithium content is relatively depleted and δ... 7 When the Li value is negative, the depositional environment is determined to be a marine sedimentary system; S304. Based on the source identification and sedimentary environment inversion results, a three-stage gallium-lithium partition coupling evolution model of mineralization was established. This three-stage partition coupling model restored the element migration path of bauxite from the weathering of the parent rock, transportation and deposition to the later transformation. S305. Test data from three types of bauxite deposits within the study area—exothermic, in-situ sedimentary, and sedimentary-leaching altered—with high levels of geological exploration and clearly defined genetic types based on geological evidence, were selected as training samples. The measured gallium and lithium contents, the calculated gallium-to-titanium ratio, and the measured δ0... 7 Using Li value as the input variable, cluster analysis algorithm was employed to identify the natural aggregation characteristics of the three types of mineral deposit samples in the multidimensional geochemical parameter space. Discriminant analysis algorithm was then used to solve the optimal classification interface equation between each category, determining the optimal classification interface equation for the three types of mineral deposits based on gallium content, lithium content, gallium-titanium ratio, and δ. 7 Quantitative distribution boundary in a multidimensional parameter space formed by Li values.
7. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 1, characterized in that, S4 specifically includes the following steps: S401. For weathered bauxite deposits from other locations, the discrimination threshold condition is set as gallium content greater than 30 × 10⁻⁻⁶. 6 The gallium-to-titanium ratio is greater than 0.6, and the lithium content is less than 200 × 10⁻ 6 ; S402. For in-situ sedimentary bauxite, the discrimination threshold condition is set as gallium content between 15 × 10⁻⁻⁶. 6 Up to 30×10⁻ 6 The gallium-to-titanium ratio is between 0.2 and 0.5, and the lithium content is between 500 × 10⁻⁻⁻⁶. 6 Up to 2000×10⁻ 6 Between, and δ 7 The Li value is between 0‰ and 1‰; S403. For sediment-leaching modified bauxite, the discrimination threshold condition is set as gallium content between 10 × 10⁻⁻⁶. 6 Up to 25×10⁻ 6 Between these values, the gallium-to-titanium ratio is less than 0.3, and the lithium content is less than 300 × 10⁻ 6 And the chemical alteration index value is greater than 95; S404. Collect several bauxite samples of unknown origin from the study area as a verification sample set, perform all testing and analysis procedures on the verification samples, and obtain the geochemical parameters of each verification sample.
8. The method for determining the genesis of sedimentary bauxite based on gallium / lithium elemental distribution according to claim 7, characterized in that, S4 specifically includes the following steps: S405. Substitute the geochemical parameters of the verification sample into the solidified threshold standard system to determine the genetic type, and compare the determination results with the actual genesis confirmed by detailed geological exploration to calculate the discrimination accuracy. S406. Set the model solidification qualification standard as a discrimination accuracy of not less than 90%. When the discrimination accuracy of the first verification meets the qualification standard, the discrimination model is directly solidified. When the discrimination accuracy is less than 90%, the batch of verification samples is added to the training sample database, and cluster analysis and discriminant analysis are re-executed to correct the distribution boundaries between each category. Iterative optimization is carried out until the discrimination accuracy meets the qualification standard. S407. Based on the classification interface equation and threshold parameters in the solidified model, compile a gallium-lithium dual-element collaborative discrimination chart. This chart uses the gallium-titanium ratio as the x-axis and the lithium content as the y-axis, and labels δ. 7 Contour lines for Li values are used to divide the region into zones. A quantitative standard table of regional genetic types is compiled simultaneously. This table lists the numerical ranges and judgment priorities of the three types of deposits on each discrimination index. The map and standard table are output as standardized results.