Method for identifying indication element of metallogenic fluid of magma hydrothermal deposit

Abstract

The invention relates to the technical field of magma hydrothermal deposit geological exploration, in particular to a method for identifying indication elements of metallogenic fluid of a magma hydrothermal deposit, which comprises the following steps: firstly, systematically collecting unaltered protolith and all alteration zone rock samples, and carrying out total rock geochemical analysis; secondly, determining an inert component based on an Isocon graphical method, and quantitatively calculating the relative mass mobility of each element so as to judge the immigration or emigration behavior of each element; then, adopting Spearman rank correlation analysis and setting a statistical threshold value, and objectively extracting a strong positive correlation element combination from the data; and finally, carrying out cross validation on the immigration element and the strong positive correlation combination, and comprehensively determining an indication element combination closely related to the metallogenic fluid activity. According to the method, the conversion from experience judgment to quantitative and statistical analysis is realized, the accuracy and reliability of indication element identification are remarkably improved, and an effective technical means is provided for deposit cause research and mineral exploration.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology for magmatic hydrothermal deposits, and specifically to a method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits. Background Technology

[0002] Magmatic hydrothermal deposits are a crucial source of key metals globally, including copper, molybdenum, gold, silver, tin, and tungsten. The formation of these deposits essentially stems from the complex exchange of matter and energy between hydrothermal fluids from deep magma chambers and the surrounding rocks during their migration, resulting in the precipitation and enrichment of ore-forming materials in favorable tectonic locations. Therefore, accurately identifying the geochemical characteristics of ore-forming fluids, especially their unique elemental assemblages (i.e., indicator elements), is of paramount importance for understanding the mineralization process and guiding mineral exploration. For a long time, the mainstream methods for identifying indicator elements of ore-forming fluids in mineral deposit research and exploration geochemistry practice have mainly included: identifying single-element anomalies, using empirical elemental assemblages, and traditional elemental correlation analysis. A method that can accurately identify indicator element assemblages closely related to specific ore-forming fluid activities is lacking.

[0003] The present invention aims to overcome the shortcomings of the prior art and provide a more accurate, reliable and geologically significant method for identifying indicator elements. Summary of the Invention

[0004] The purpose of this invention is to provide a method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits. By quantitatively analyzing the mass migration rate of elements during the alteration process and combining it with statistically relevant element co-occurrence combinations for comprehensive judgment, the method achieves accurate and objective identification of specific indicator elements of ore-forming fluids.

[0005] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0006] A method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits includes the following steps:

[0007] S1: Sample collection and data acquisition: Collect unaltered protolith samples and rock samples from different alteration zones within the exploration area, and conduct whole-rock geochemical analysis on all samples to obtain the content data of major elements, trace elements and rare earth elements.

[0008] S2: Quantitative analysis of element migration behavior: Based on the unaltered protolith, the relative mass migration of each element in each alteration zone is calculated using a mass balance method based on inert component calibration, thereby determining the migration state of each element during the alteration process.

[0009] S3: Element combination correlation analysis: Perform nonparametric correlation analysis on the content data obtained in step S1, calculate the correlation coefficient between element pairs, and screen out element combinations with strong positive correlation based on the preset correlation coefficient and significance threshold.

[0010] S4: Comprehensive determination of indicator elements: Select elements that were identified as immigrants in step S2 and belong to the same strongly positively correlated element combination in step S3, and determine this group of elements as the indicator elements of the ore-forming fluid.

[0011] Furthermore, the mass balance method based on inert component calibration in step S2 is the Isocon graphical method, which specifically includes: drawing a scatter plot of element content in the original rock and altered rock and fitting a straight line passing through the origin to determine the element components that behave inertly during the alteration process as internal standards.

[0012] Furthermore, the Isocon graphical method further includes a standardization step: Except for the original rock sample, a standardization factor K for a certain alteration zone is set to 1, and the standardization factors K for the remaining alteration zones are calculated using Formula 1:

[0013]

[0014] Where K is the standardization factor. The content of inactive component i in the alteration zone corresponding to the selected normalization factor of 1. The content of the inactive component i in the calculated alteration zone.

[0015] Furthermore, the mass migration rate of element m in alteration zone A relative to the original rock O is calculated using the following formula:

[0016]

[0017] A positive quality mobility rate indicates immigration, while a negative rate indicates immigration. This refers to the element mass transfer rate; This refers to the change in mass of element m as it moves from the original rock to alteration zone A. The mass of element m in the original rock; The concentration of element m in sample A of the alteration zone; The concentration of element m in the original rock; The concentration of inactive component i in the original rock; The concentration of inactive component i in the alteration zone A sample.

[0018] Furthermore, the nonparametric correlation analysis in step S3 is Spearman's rank correlation analysis, and the correlation coefficient and significance threshold are: the absolute value of the Spearman correlation coefficient. ≥0.7, and the significance p-value <0.05.

[0019] Furthermore, the whole-rock geochemical analysis described in step S1 includes at least the quantitative analysis of the following components: major elements SiO2, Al2O3, TFe2O3, MgO, CaO, Na2O, K2O, TiO2, P2O5, MnO and loss on ignition (LOI); trace elements Cu, Zn, Pb, Sn, Rb, Sr, Zr, Nb, Mo, Ba, Hf, Ta, W, Th, U; and rare earth elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y.

[0020] Furthermore, the criteria for determining immigration in step S4 are as follows: in the standardized Isocon diagram, data points located above the Isocon line indicate that the corresponding element is immigration, and data points located below the line indicate that the corresponding element is immigration.

[0021] On the other hand, the present invention proposes a combination of ore-forming fluid indicator elements identified by the above method, the combination comprising multiple elements that migrate synergistically during the alteration process and have a strong positive correlation, for comprehensively indicating the activity of ore-forming fluids.

[0022] On the other hand, this invention proposes the application of the above-mentioned combination of ore-forming fluid indicator elements in the exploration of magmatic hydrothermal deposits for delineating prospecting target areas or evaluating mineralization alteration zones.

[0023] The beneficial effects of this invention are:

[0024] This invention achieves precise quantification of element migration behavior in open systems through mass balance calculations based on inert components. Traditional methods, which directly compare concentrations, are prone to misjudgment due to changes in the total rock mass during alteration. This invention uses the Isocon graphical method to determine the inert component as an internal standard and normalizes the apparent concentration using a migration rate formula, eliminating interference from mass changes. The resulting mass migration rate objectively reflects the net gain or loss of elements on a fixed mass benchmark, providing a reliable quantitative basis for subsequent analysis.

[0025] This invention combines Spearman's rank correlation analysis with dual thresholds for correlation coefficient and significance. ≥0.7, p<0.05, systematic mining of the entire element dataset. Overcoming the subjectivity of empirical selection, it automatically screens element combinations with significant synergistic changes in spatial distribution through statistical tests. This reflects elemental symbiotic relationships controlled by the same fluid or geochemical processes, making its indicative significance more reliable.

[0026] This invention does not rely solely on migration information or correlations, but requires candidate elements to simultaneously meet two conditions: migration and belonging to a statistically significant combination of strong positive correlations. This ensures that the elements ultimately selected are both direct products of ore-forming fluids and exhibit synergistic enrichment behavior, thereby effectively eliminating interference from single anomalies or the influence of irrelevant symbiosis, and significantly improving the directionality and interpretive depth of indicator element combinations.

[0027] From field sampling standards and laboratory analysis projects to standardized Isocon diagram construction, statistical screening with unified thresholds, and comprehensive judgment based on clear rules, the process of this invention reduces reliance on human experience and ensures the consistency and comparability of analysis results. It is not only applicable to the identification of indicator elements in different types of magmatic hydrothermal deposits, but its quantitative migration combined with statistical correlation approach also provides a referable analytical paradigm for the study of other hydrothermal mineralization systems.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A standardized Isocon diagram illustrating the migration patterns of major elements in various alteration zones of the Bainiuchang magmatic hydrothermal deposit;

[0031] Figure 2 A standardized Isocon diagram illustrating the migration patterns of trace elements in various alteration zones of the Bainiuchang magmatic hydrothermal deposit;

[0032] Figure 3 A standardized Isocon schematic diagram of the migration patterns of rare earth elements in various alteration zones of the Bainiuchang magmatic hydrothermal deposit.

[0033] Figure 4 Comparison of major element mass migration in altered monzogranite of the Bainiuchang magmatic hydrothermal deposit;

[0034] Figure 5 Comparison of trace and rare earth element mass migration in altered monzogranite of the Bainiuchang magmatic hydrothermal deposit;

[0035] Figure 6 A thermal curve showing the elemental correlation of the Bainiuchang magmatic hydrothermal deposit;

[0036] Figure 7This is an overall schematic diagram of a method for identifying ore-forming fluid indicator elements in magmatic hydrothermal deposits according to the present invention. Detailed Implementation

[0037] 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.

[0038] Example 1

[0039] This embodiment describes a method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits, comprising: field investigation, delineation of alteration zones, collection of samples from each alteration zone and sending them to the laboratory for analysis, determination of element migration patterns in each alteration zone, identification of element combinations by calculating the correlation between elements and drawing a correlation heatmap, and determination of indicator elements based on the migration comparison and correlation relationships of each element. The steps are as follows:

[0040] The process of collecting samples from each alteration zone and sending them to the laboratory for analysis includes:

[0041] The collected samples from each alteration zone refer to rocks located in different alteration zones as well as unaltered rocks. Unaltered rocks refer to protoliths within the area that have not been weathered or eroded, nor altered by magmatic hydrothermal processes. Rocks located in different alteration zones refer to typical rocks sampled from each alteration zone based on the alteration zones defined in step one. Laboratory analysis should involve whole-rock major element (LOI, SiO2, Al2O3, TFe2O3, MgO, CaO, Na2O, K2O, P2O5, TiO2, MnO), trace element (Cu, Zn, Pb, Sn, Rb, Sr, Zr, Nb, Mo, Ba, Hf, Ta, W, Th, U) tests to analyze the content of each element.

[0042] The determination of the element migration patterns in each alteration zone includes:

[0043] (1) After obtaining the results of whole-rock principal and trace analysis in the laboratory, the element / oxide detection values ​​of the samples in each alteration zone were averaged. Since hydrothermal alteration is an open geological system, the content change of a certain element depends not only on the degree of migration during the alteration process, but also on the change in the total mass of the geological system. Therefore, it is necessary to determine the inactive components during the alteration process and to perform mass balancing of the geological samples before and after the system is opened in order to eliminate the influence of the change in the total mass of the samples.

[0044] (2) Inactive components were determined using the Isocon plot method, i.e., the content of the corresponding element / oxide in the original rock sample was plotted as the x-axis and the content of the corresponding element / oxide in the alteration zone sample was plotted as the y-axis. If certain elements / oxides could be fitted into a straight line passing through the origin, then these elements / oxides could be identified as inactive components in the alteration process. The mass balance method adopted the standardized Isocon plot method.

[0045] (3) The content of each element / oxide in different alteration zones is standardized by determining the inactive components, with the aim of adjusting the Isocon lines corresponding to different alteration zones to the same slope and drawing a standardized Isocon diagram.

[0046] a. The standardization process is as follows: Except for the original rock sample, a standardization factor K for a certain alteration zone is set to 1. The standardization factors K for the remaining alteration zones are calculated using Formula 1:

[0047] Formula 1:

[0048]

[0049] Where K is the standardization factor. The content of inactive component i in the alteration zone corresponding to the selected normalization factor of 1. The content of the inactive component i in the calculated alteration zone.

[0050] b. If the corresponding element / oxide spot is above Isocon, it means that the element / oxide migrated in during the alteration process.

[0051] c. If the corresponding element / oxide is below the Isocon, it means that the element / oxide migrated out during the etching process.

[0052] (4) Calculate the element migration rate using Formula 2, and then draw a comparison chart of element mass migration:

[0053] Formula 2:

[0054]

[0055] in This refers to the element mass transfer rate; This refers to the change in mass of element m as it moves from the original rock to alteration zone A. The mass of element m in the original rock; The concentration of element m in sample A of the alteration zone; The concentration of element m in the original rock; The concentration of inactive component i in the original rock; The concentration of inactive component i in alteration zone A sample is given. The mass migration of each element in each alteration zone is obtained according to Formula 2, and a comparison chart of elemental mass migration is plotted using Origin software.

[0056] The step of identifying element combinations by calculating the correlation between elements and drawing a correlation heatmap includes:

[0057] (1) Prepare the principal and trace data of the original rock and each alteration zone sample, with rows representing samples and columns representing elements / oxides. Import the data into Origin software, use the Spearman method to calculate the correlation coefficient and generate a correlation heatmap for visualization analysis. In the correlation heatmap, red tones represent positive correlations, blue tones represent negative correlations, and the darker the color, the stronger the correlation.

[0058] (2) By setting the correlation coefficient And a threshold for the p-value, selecting feasible combinations of strongly correlated elements. This includes: setting only the correlation coefficient... Only when the p-value is greater than 0.7 and the p-value is less than 0.05 is this group of elements considered a reliable combination of strongly positively correlated elements.

[0059] The determination of the indicator element based on the migration comparison and correlation relationship of each element includes:

[0060] The above steps identified a series of strongly positively correlated elements that had migrated into the region. These elements can be categorized as: main ore-forming indicator elements, source region indicator elements, and alteration indicator elements. This allows for the determination of ore-forming fluid indicator elements.

[0061] Example 2

[0062] The method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits, as described in this invention, was implemented in the Bainiuchang magmatic hydrothermal deposit in southeastern Yunnan. The invention will be described in detail below with reference to the accompanying drawings:

[0063] According to the attached figure, a method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits specifically includes the following steps:

[0064] Step 1: Field investigation and delineation of alteration zones;

[0065] Step 2: Collect samples from each alteration zone and send them to the laboratory for analysis;

[0066] Step 3: Determine the element migration patterns in each alteration zone;

[0067] Step 4: By calculating the correlation between elements, draw a correlation heatmap to identify element combinations;

[0068] Step 5: Determine the indicator element based on the migration comparison and correlation of each element.

[0069] In a preferred embodiment, collecting samples from each alteration zone and sending them to the laboratory for analysis includes collecting samples from rocks in different alteration zones as well as unaltered rocks; the unaltered rocks refer to the original rocks in the area that have not been weathered or eroded, nor altered by magmatic hydrothermal fluids; the rocks in different alteration zones refer to typical rocks sampled from each alteration zone based on the alteration zones defined in step one. Laboratory analysis should involve testing and analyzing the content of each element in the collected samples for whole-rock major elements (LOI, SiO2, Al2O3, TFe2O3, MgO, CaO, Na2O, K2O, P2O5, TiO2, MnO), trace elements, and rare earth elements (S, Cu, Zn, Pb, As, Rb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, etc.).

[0070] In this embodiment, step three mainly includes:

[0071] (1) After obtaining the results of whole-rock principal and trace analysis in the laboratory, the element / oxide detection values ​​of the samples in each alteration zone were averaged. Since hydrothermal alteration is an open geological system, the content change of a certain element depends not only on the degree of migration during the alteration process, but also on the change in the total mass of the geological system. Therefore, it is necessary to determine the inactive components during the alteration process and to perform mass balancing of the geological samples before and after the system is opened in order to eliminate the influence of the change in the total mass of the samples.

[0072] (2) Inactive components were determined using the Isocon plot method, i.e., the content of the corresponding element / oxide in the original rock sample was plotted as the x-axis and the content of the corresponding element / oxide in the alteration zone sample was plotted as the y-axis. If certain elements / oxides could be fitted into a straight line passing through the origin, then these elements / oxides could be identified as inactive components in the alteration process. The mass balance method adopted the standardized Isocon plot method.

[0073] (3) The content of each element / oxide in different alteration zones is standardized by determining the inactive components, with the aim of adjusting the Isocon lines corresponding to different alteration zones to the same slope and drawing a standardized Isocon diagram.

[0074] a. The standardization process is as follows: Except for the original rock sample, a standardization factor K for a certain alteration zone is set to 1. The standardization factors K for the remaining alteration zones are calculated using Formula 1:

[0075] Formula 1:

[0076]

[0077] Where K is the standardization factor. The content of inactive component i in the alteration zone corresponding to the selected normalization factor of 1. The content of the inactive component i in the calculated alteration zone.

[0078] b. If the corresponding element's projection point is above the Isocon, it means that the element migrated in during the alteration process. (Refer to...) Figure 1-3 Elements / oxides such as MnO, TFe2O3, Zn, Pb, Cu, and Zr migrate in as a whole.

[0079] c. If the corresponding element's projection point is below the Isocon, it means that the element migrated out during the alteration process. (Refer to...) Figure 1-3 Elements such as Na₂O, K₂O, Mo, Ta, W, U, and Th migrate out.

[0080] (4) Calculate the element migration rate using Formula 2, and then draw a comparison chart of element mass migration:

[0081] Formula 2:

[0082]

[0083] in This refers to the element mass transfer rate; This refers to the change in mass of element m as it moves from the original rock to alteration zone A. The mass of element m in the original rock; The concentration of element m in sample A of the alteration zone; The concentration of element m in the original rock; The concentration of inactive component i in the original rock; The concentration of inactive component i in alteration zone A sample is given. The mass migration of each element in each alteration zone is obtained according to Formula 2, and a comparison chart of elemental mass migration is plotted using Origin software.

[0084] In this embodiment, step four includes:

[0085] (1) Prepare the principal and trace data of the original rock and each alteration zone sample, with rows representing samples and columns representing elements / oxides. Import the data into Origin software, use the Spearman method to calculate the correlation coefficient and generate a correlation heatmap for visualization analysis. In the correlation heatmap, red tones represent positive correlations, blue tones represent negative correlations, and the darker the color, the stronger the correlation.

[0086] (2) By setting the correlation coefficient And a threshold for the p-value, selecting feasible combinations of strongly correlated elements. This includes: setting only the correlation coefficient... Only when the p-value is greater than 0.7 and the p-value is less than 0.05 is this group of elements considered a reliable combination of strongly positively correlated elements.

[0087] In this embodiment, step five includes:

[0088] Through the above steps, a series of strongly positively correlated elements from the migration process are identified. These elements can be categorized into: main ore-forming indicator elements, source region indicator elements, and alteration indicator elements, to determine the ore-forming fluid indicator elements.

[0089] Reference Figure 4-6 A combination of elements was identified: Cu, Ba, Zn, Pb, SiO2, and Hf. Among them, Cu, Zn, and Pb are the main mineralization indicators, Ba and SiO2 are alteration indicators, and Hf is the source region indicator.

[0090] In summary, this invention proposes a method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits. First, a systematic collection of unaltered protoliths and rock samples from various alteration zones is performed for whole-rock geochemical analysis. Second, inert components are determined using the Isocon diagram method, and the relative mass migration rates of each element are quantitatively calculated to identify their migration-in or migration-out behavior. Subsequently, Spearman rank correlation analysis is employed, and statistical thresholds are set to objectively extract strongly positively correlated element combinations from the data. Finally, the migrating elements are cross-validated with the strongly positively correlated combinations to comprehensively determine the indicator element combinations closely related to ore-forming fluid activity. This invention achieves a shift from empirical judgment to quantitative and statistical analysis, significantly improving the accuracy and reliability of indicator element identification and providing an effective technical means for ore deposit genetic research and mineral exploration.

[0091] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for identifying indicator elements of ore-forming fluids in magmatic hydrothermal deposits, characterized in that, Includes the following steps: S1: Sample collection and data acquisition: Collect unaltered protolith samples and rock samples from different alteration zones within the exploration area, and conduct whole-rock geochemical analysis on all samples to obtain the content data of major elements, trace elements and rare earth elements. S2: Quantitative analysis of element migration behavior: Based on the unaltered protolith, the relative mass migration of each element in each alteration zone is calculated using a mass balance method based on inert component calibration, thereby determining the migration state of each element during the alteration process. S3: Element combination correlation analysis: Perform nonparametric correlation analysis on the content data obtained in step S1, calculate the correlation coefficient between element pairs, and screen out element combinations with strong positive correlation based on the preset correlation coefficient and significance threshold. S4: Comprehensive determination of indicator elements: Select elements that were identified as immigrants in step S2 and belong to the same strongly positively correlated element combination in step S3, and determine this group of elements as the indicator elements of the ore-forming fluid.

2. The method as described in claim 1, characterized in that, The mass balance method based on inert component calibration mentioned in step S2 is the Isocon graphical method, which specifically includes: drawing a scatter plot of element content in the original rock and altered rock and fitting a straight line passing through the origin to determine the element components that behave inertly during the alteration process as internal standards.

3. The method as described in claim 2, characterized in that, The Isocon graphical method further includes a standardization step: Except for the original rock sample, a standardization factor K for a certain alteration zone is set to 1, and the standardization factors K for the remaining alteration zones are calculated using the following formula: Where K is the standardization factor. The content of inactive component i in the alteration zone corresponding to the selected normalization factor of 1. The content of the inactive component i in the calculated alteration zone.

4. The method as described in claim 3, characterized in that, The mass migration rate of element m in alteration zone A relative to the protolith O is calculated using the following formula: in This refers to the element mass transfer rate; This refers to the change in mass of element m as it moves from the original rock to alteration zone A. The mass of element m in the original rock; The concentration of element m in sample A of the alteration zone; The concentration of element m in the original rock; The concentration of inactive component i in the original rock; The concentration of inactive component i in the alteration zone A sample.

5. The method as described in claim 1, characterized in that, The nonparametric correlation analysis in step S3 is Spearman's rank correlation analysis, and the correlation coefficient and significance threshold are: the absolute value of the Spearman correlation coefficient. ≥0.7, and the significance p-value <0.

05.

6. The method as described in claim 1, characterized in that, The whole-rock geochemical analysis described in step S1 includes at least the quantitative analysis of the following components: major elements SiO2, Al2O3, TFe2O3, MgO, CaO, Na2O, K2O, TiO2, P2O5, MnO and loss on ignition (LOI); trace elements Cu, Zn, Pb, Sn, Rb, Sr, Zr, Nb, Mo, Ba, Hf, Ta, W, Th, U; and rare earth elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y.

7. The method as described in claim 1, characterized in that, The criteria for determining immigration in step S4 are as follows: In the standardized Isocon diagram, data points located above the Isocon line indicate that the corresponding element is immigration, and data points located below the line indicate that the corresponding element is immigration.

8. The combination of ore-forming fluid indicator elements identified by the method of any one of claims 1-7, characterized in that, The combination includes multiple elements that migrate synergistically during the alteration process and have a strong positive correlation, used to comprehensively indicate the activity of ore-forming fluids.

9. The application of the ore-forming fluid indicator element combination as described in claim 8 in the exploration of magmatic hydrothermal deposits for delineating prospecting target areas or evaluating mineralization alteration zones.

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