Data processing method of line scanning U-Pb dating of accessory minerals in high-common lead hydrothermal fluids

Abstract

The present invention discloses a method for processing line scanning U-Pb dating data of high-common lead hydrothermal accessory minerals, and the method steps are as follows: using the age determination method to deduct common lead from the matrix-matched common lead hydrothermal accessory mineral dating standard material, and calculate the U-Pb isotope fractionation coefficient; completing the matching of mass spectrum files and laser log files, realizing the segmentation of continuous mass spectrum data, extracting the analysis sequence, background and integration time, and analysis point space coordinates; performing background correction, isotope content and ratio calculation on the completed matching mass spectrum data; using the extracted sequence space information and multiple line scanning mass spectrum data matching and drawing the isotope content, ratio and age space distribution map. The advantages of the present invention are: this method can effectively process LA-ICP-MS high-common lead hydrothermal accessory mineral U-Pb dating data, can improve the LA-ICP-MS dating efficiency, and obtain the high-resolution isotope content and age variation law of the sample.

Description

Technical Field

[0001] The invention relates to a LA-ICP-MS line scanning U-Pb dating test method for common lead hydrothermal accessory minerals, in particular to a line scanning U-Pb dating data processing method for high common lead hydrothermal accessory minerals. Background Art

[0002] The LA-ICP-MS method for U-Pb dating of hydrothermal accessory minerals is a commonly used economical, rapid and accurate method for mineral isotope age detection, which is applied to the study of the formation era of igneous rocks, metamorphism and hydrothermal events. In recent years, with the advancement of analytical testing technology, low-uranium hydrothermal or accessory minerals can also be accurately tested for their isotopic composition using the LA-ICP-MS method. However, since the hydrothermal or accessory mineral standard materials contain high levels of common lead, the LA-ICPMS hydrothermal accessory mineral U-Pb dating data processing faces great challenges. DM Chew, J A Petrus and BS Kamber proposed a method to correct common lead in the standard sample. This method deducts common lead from the test value and theoretical value of the U-Pb isotope value measured by the standard sample, but this method can only be applied to the case where the U-Pb isotope content of the standard material is uniform. For some hydrothermal accessory minerals (such as calcite, wolframite and cassiterite), the matrix-matched standard materials currently developed contain high levels of common lead and their U-Pb isotope composition is not uniform. In the LA-ICP-MS U-Pb dating of hydrothermal accessory minerals, the calculation of U-Pb isotope fractionation coefficients is affected by the standard samples due to the inhomogeneity of the standard samples and the existence of the denudation depth effect. In short, the inhomogeneity of the U-Pb isotope composition in the standard materials leads to inaccurate processing of mineral U-Pb dating data.

[0003] In view of the above problems, this paper proposes a data processing method for U-Pb dating of hydrothermal accessory minerals using line scanning LA-ICP-MS to solve the problem of inaccurate processing results caused by the uneven U-Pb isotopic composition of standard materials. Summary of the invention

[0004] The purpose of the present invention is to provide a data processing method for line scanning U-Pb dating of high-common lead hydrothermal accessory minerals. This method can reasonably deduct the common lead composition in the standard sample and avoid the influence of the analysis deviation of the standard substance on the sample analysis. It is practical in solving the U-Pb dating of high-common lead hydrothermal accessory minerals containing LA-ICP-MS.

[0005] The technical solution adopted by the present invention is as follows: a method for processing line scanning U-Pb dating data of high-common lead hydrothermal accessory minerals, characterized by the following steps:

[0006] Step 1: Use the age determination method to deduct the common lead from the matrix-matched hydrothermal accessory mineral dating standard material, and calculate the U-Pb isotope fractionation coefficient in the analysis test;

[0007] Step 2: Complete the matching of mass spectrum files and laser log files, realize the segmentation of continuous mass spectrum data, extract the analysis sequence, background and integration time, and analysis point spatial coordinates;

[0008] Step 3: Perform background correction, outlier removal, interpolation processing, and isotope content and ratio calculation on the completed matching mass spectrum data;

[0009] In the fourth step, the extracted sequence spatial information and multiple line-scan mass spectrometry data were matched and the spatial distribution maps of isotope content, ratio and age were drawn.

[0010] Furthermore, the high-common lead hydrothermal accessory minerals are LA-ICP-MS high-common lead hydrothermal accessory minerals, that is, LA-ICP-MS high-common lead hydrothermal accessory mineral line scan U-Pb dating data: including the time series isotope signal intensity obtained by mass spectrometry analysis ( Figure 1 ) and laser log files ( Figure 2 );

[0011] The mass spectrum data at least includes the time Time={T1,T2,T3,…,T n}; Isotope count intensity 206 Pb int ={ 206 Pb1, 206 Pb2, 206 Pb3,… 206 Pb n}, 207 Pb int ={ 207 Pb1, 207 Pb2, 207 Pb3,…, 207 Pb n}and 238 U int ={ 238 U1, 238 U2, 238 U3,…, 238 U n}.

[0012] Where: Tn represents the mass spectrometry data detection time, 206Pb int , 207 Pb int and 238 U int Respectively represent 206 Pb, 207 Pb and238 U average counting intensity;

[0013] The laser log file contains a csv file automatically generated when the laser analyzes the sample sequence, which contains the timestamp (Timestamp), sample name (Comment), laser state (Laser State), and analysis point spatial coordinates (X, Y) information.

[0014] Furthermore, the definition of ordinary lead deduction using the age determination method is specifically as follows: because of the common mixing, the Pb isotope composition of the standard material test contains radioactive lead and ordinary lead. Before the isotope fractionation calculation of the standard material is performed, a reasonable deduction calculation of the ordinary lead is required.

[0015] If the dating standard material is not mixed with common lead at the beginning of its formation, 206 Pb / 238 U and 207 Pb / 235 U age remains consistent. After reasonable common lead deduction, the dating standard material falls near the concord line on the Tera-Wasserburg diagram or Wetherill diagram ( Figure 3 ).

[0016] The specific principle and process of the first step of the age determination method to deduct the common lead in the matrix matching standard material are as follows:

[0017] According to the Stacey-Kramers crustal Pb evolution model, the relationship between common lead, radiogenic lead and measured lead isotopic compositions is as follows:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] In the above formula: and represents the common lead composition of the standard material; and Represents the radioactive lead isotopic composition of the standard material; 207 Pb m , 206 Pb mIt is a standard substance for mass spectrometer testing 207 Pb and 206 The average counting intensity of Pb; 204 Pb c Representative of ordinary lead 204 Pb theoretical value; e is a natural constant; t represents the age of the standard substance; λ235 and λ238 represent 235 U and 238 U decay constant; r represents radioactive U-Pb isotope; c represents non-radioactive U-Pb isotope; m represents the actual measured value;

[0025] By solving equations (1) to (6), the radioactive U-Pb isotope of the standard substance ordinary lead after deduction is obtained:

[0026]

[0027] In the formula represents the isotopic composition of lead of radiogenic origin; 206 Pb m and 207 Pb m , 238 U m Representative standard substances 206 Pb, 207 Pb and 238 The measured average counting intensity of the U isotope;

[0028] Using formulas (6) and (7), the U-Pb isotopic composition of the standard material after deducting common lead is calculated.

[0029] Furthermore, the U-Pb isotope fractionation coefficient in step 1 of the present invention can be expressed as:

[0030]

[0031]

[0032] In the above formula, Corr76 and Corr86 represent 207 Pb / 206 Pb and 238 U / 206 Fractionation coefficient of Pb; Representative standard material after calibration radioactivity 207 Pb / 206 Pb composition; Representative standard material after calibration radioactivity 206 Pb / 238 U composition; Represents the theoretical calculation based on the age of the standard sample 207 Pb / 206Pb value; Represents the theoretical calculation based on the age of the standard sample 206 Pb / 238 U value( Figure 3 ).

[0033] Furthermore, the specific operation of matching the mass spectrum data and the laser log file in step 2 of the present invention is as follows: matching is performed according to the Time in the mass spectrum data and the Timestamp in the laser log file to achieve the mass spectrum data Time, 206 Pb int , 207 Pb int and 238 U int Match with the laser state (Laser State) and the analysis point spatial coordinates (X, Y). The matching result forms an xls file, the content of which is as follows Figure 4 shown.

[0034] Furthermore, the method for performing background correction, outlier removal and interpolation calculation on the completed matching mass spectrum data in step 3 of the present invention is as follows:

[0035] The specific method of background correction is as follows: the U-Pb isotope count intensity obtained by mass spectrometry analysis of the sample 206 Pb int , 207 Pb int and 238 U int , minus the corresponding instrument backgrounds Bsl206, Bsl207 and Bsl238;

[0036] The specific method of outlier elimination is to eliminate the U and Pb data obtained by mass spectrometry analysis that are below the instrument detection limit.

[0037] The specific method of interpolation is: for data with U and Pb less than the critical set value, interpolation is performed based on the overall change trend of the previous and next data. 206 Pb, 207 Pb, 208 Pb, 232 Th and 238 The U times are Del206, Del207, Del208, Del232 and Del238 respectively. 238 U int <50 or 206 Pb int If <25 data is i rows, the following method is used for interpolation:

[0038]

[0039]

[0040]

[0041] In the formula, Bsl206, Bsl207 and Bsl238 represent 206 Pb, 207 Pb and 238 U background value; 238 U intr Represents the value after background correction, outlier removal and interpolation processing. 238 U count; 207 Pb intr Represents the value after background correction, outlier removal and interpolation processing. 207 Pb count; 206 Pb intr Represents the value after background correction, outlier removal and interpolation processing. 207 Pb count; Time i Represents the analysis time of the i-th row of data; Represents row i of data 238 Average counting intensity of U; Represents row i of data 207 Average counting intensity of Pb; Represents row i of data 206 The average counting intensity of Pb; Figure 5 As shown, T c Represents the time required for one detection cycle of the detector, T s Represents the time difference between detectors scanning isotopes of different masses. There is the following relationship between Tc and Ts:

[0042] T s =T C -(Del206+Del207+Del208+Del232+Del238)*0.25 (13)

[0043] For the data that have completed background correction, outlier removal, and interpolation processing, the isotope composition and corresponding error are calculated using the following formula:

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] In the above formula: 238 U / 206 Pb represents the radioactivity of the sample 238 U / 206 Pb isotopic composition; 207 Pb / 206 Pb represents the radioactivity of the sample 207 Pb / 206 Pb isotope composition; Sig206, Sig207 and Sig238 represent 206 Pb, 207 Pb and 238 U counts correspond to the absolute error, 86 Err and 76 Err represents 238 U / 206 Pb and 207 Pb / 206 The error of Pb value; T68 and T75 represent 206 Pb / 238 U and 207 Pb / 235 U isotope pattern age. The calculation results are as follows Figure 6 shown.

[0054] Furthermore, in step 4, the spatial distribution of isotope content, ratio and age is plotted as follows: The age of hydrothermal accessory minerals can be determined using the Tera-Wasserburg diagram ( Figure 7 )、Wetherill diagram( Figure 8 ) or Bayesian regression ( Fig. 9 ) method. According to the list file, the spatial coordinates (X, Y) of each analysis point are obtained, and the above isotope processing results and position information are matched to draw the spatial distribution map of U-Pb isotopes or ages ( Fig.10 ).

[0055] The advantages of the present invention are: this scheme proposes a new method for processing LA-ICP-MS high-common lead hydrothermal accessory mineral line scanning U-Pb dating data; by processing LA-ICP-MS calcite, apatite, cassiterite and other mineral line scanning U-Pb dating data through this method, the result is not affected by the common lead in the standard sample, the calculated mineral age result is correct, the spatial isotope variation law can be drawn, and efficient LA-ICP-MS hydrothermal accessory mineral U-Pb dating can be achieved. The results show that: this method can effectively solve the problem of high common lead and U-Pb isotope inhomogeneity in dating standard materials, and is practical in LA-ICP-MS high common lead hydrothermal accessory mineral U-Pb dating test. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram of mass spectrometry data structure of the present invention.

[0057] Figure 2 This is a schematic diagram of the laser log file structure of the present invention.

[0058] Figure 3 This is a schematic diagram of the common lead correction principle of the age determination model of the present invention.

[0059] Figure 4 This is a schematic diagram of the data structure of the mass spectrum and laser log file matching result list file of the present invention.

[0060] Figure 5 Schematic diagram of the relationship between the scanning time and signal intensity of the quadrupole mass spectrometer detector of the present invention.

[0061] Figure 6 This is a schematic diagram of the data structure of the processing result of the present invention.

[0062] Figure 7 This is a schematic diagram of age calculation using the Tera-Wasserburg diagram as a result of the processing of the present invention.

[0063] Figure 8 This is a schematic diagram of age calculation using the Wetherill diagram as a result of the processing of the present invention.

[0064] Fig. 9 This is a schematic diagram of age calculation using the Bayesian regression method for the processing results of the present invention.

[0065] Fig.10 This is a schematic diagram of the spatial distribution of U-Pb isotopes as a result of the processing of the present invention. DETAILED DESCRIPTION

[0066] The present invention works and is implemented in this way. The hydrothermal accessory mineral dating standard materials and samples generally contain a higher common lead composition. Therefore, when using LA-ICP-MS hydrothermal accessory mineral U-Pb dating, the unevenness of the U-Pb isotope of the standard material used to correct the signal data not only affects the fractionation coefficient, but also brings the deviation of the standard sample into the sample. Therefore, it is key to accurately deduct the common lead in the standard material to obtain the correct U-Pb fractionation coefficient in the analysis process. In addition, due to the deep fractionation effect in the point ablation dating process, the present invention proposes to use a line scanning method for laser ablation dating, which can not only avoid the influence caused by deep fractionation, but also obtain the maximum U / Pb change, so that the intersection age of the hydrothermal accessory mineral containing common lead can be obtained by regression method. The present invention uses a standard substance containing common lead as an external U-Pb isotope correction, proposes an age determination model method to deduct the common lead in the standard substance, and then calculates the instrument fractionation factor. According to the calculated fractionation factor, each scanning cycle data is subjected to separate background deduction, outlier elimination and interpolation processing, and finally the isotope composition and error are calculated to obtain the U-Pb isotope age of the mineral. The present invention uses LA-ICPMS calcite and apatite U-Pb dating data for detection and obtains good results, and obtains the correct age of the monitoring standard sample.

[0067] The present invention first introduces in detail the principle of common lead deduction of standard samples by age determination method. The age determination method only needs to provide the formation age of the standard material, without inputting the U-Pb isotope composition, and uses the age to calculate the theoretical mineral U-Pb isotope composition, and combines the U-Pb isotope composition measured by the mineral standard material to calculate the U-Pb isotope composition of the standard material before mixing into the common lead, and then calculates the U-Pb isotope fractionation coefficient in the analysis and testing process. The obtained fractionation coefficient performs isotope fractionation correction and calculation on the sample and the standard material, obtains a large amount of data results, and uses the result data to perform Tera-Wasserburg diagram, Wetherill diagram and Bayesian regression method to calculate the age, and obtain the mineral isotope intersection age and common lead composition. Finally, by matching the laser log file and the mass spectrometry file, efficient and high-resolution mineral U-Pb isotope composition and age are achieved.

[0068] 1. The age determination method deducts the common lead content in the standard substance.

[0069] LA-ICP-MS line scan U-Pb dating data includes time Time={T1,T2,T3,…,T n}; 206 Pb, 207 Pb, 238 The U counting intensities are: 206 Pb int ={ 206Pb1, 206 Pb2, 206 Pb3,… 206 Pb n}, 207 Pb int ={ 207 Pb1, 207 Pb2, 207 Pb3,…, 207 Pb n}and 238 U int ={ 238 U1, 238 U2, 238 U3,…, 238 U n}( Figure 1 ).

[0070] Where: Tn represents the mass spectrometry data detection time, 206Pb int , 207 Pb int and 238 U int Respectively represent 206 Pb, 207 Pb and 238 U is the average count intensity.

[0071] Assuming that the common lead in the standard material is only mixed in at the beginning of the mineral formation, and its isotope system remains closed thereafter, after deducting the common lead, the U-Pb isotope composition of the standard material can be calculated using the following formula:

[0072]

[0073]

[0074] In the above formula, Representative standard material after calibration radioactivity 207 Pb / 206 Pb composition; Representative standard material after calibration radioactivity 206 Pb / 238 U composition; t is the formation age of the standard material, which can be dated by ID-TIMS or SIMS U-Pb. 40 Ar- 39 The age was determined by Ar method and Re-Os isotope dating. 206 Pb m , 207 Pb m and 238 U m Represents the standard substances 206 Pb,207 Pb and 238 The average counting intensity of U isotope measurement, in CPS (average counts per second); e is a natural constant; λ 238 and λ 235 Respectively represent 238 U and 235 The decay constant of U. The final obtained and The value is the standard substance after calibration of common lead 206 Pb / 238 U and 207 Pb / 206 Pb composition.

[0075] 2. Calculation of U-Pb isotope fractionation coefficient:

[0076] like Figure 3 As shown, ( 207 Pb / 206 Pb) r and( 206 Pb / 238 U) r represents the U-Pb isotope composition after calibration of the standard material, ( 207 Pb / 206 Pb) True and( 206 Pb / 238 U) True represents the theoretical U-Pb isotopic composition of the standard sample. 207 Pb / 206 Pb and 206 Pb / 238 U fractionation coefficients Corr76 and Corr86 can be calculated using the following formula:

[0077] Corr76=( 207 Pb / 206 Pb) r / ( 207 Pb / 206 Pb) True (8)

[0078] Corr86=( 206 Pb / 238 U) r / ( 206 Pb / 238 U) True (9)

[0079] 3. Laser log file and mass spectrometry data matching

[0080] Laser log file refers to the csv file automatically generated when the laser analyzes the sample sequence, which contains information such as timestamp (Timestamp), sample name (Comment), laser state (Laser State), and analysis point spatial coordinates (X, Y). Figure 2 ).

[0081] According to the matching of the Time in the mass spectrometry data and the Timestamp in the laser log file, the mass spectrometry data Time, 206 Pb int , 207 Pb int and 238 U int Match with the laser state (Laser State) and the analysis point spatial coordinates (X, Y). The matching result forms an xls file, the content of which is as follows Figure 4 shown.

[0082] 4. Completed matching mass spectrometry data for background correction, outlier removal and interpolation calculation

[0083] The background correction, outlier removal and interpolation calculation methods for the completed matching mass spectrum data are as follows:

[0084] Interpolation is performed for U and Pb values ​​less than the critical set value. Assuming that the U-Pb isotope count intensity obtained by mass spectrometry for sample analysis is 206 Pb int , 207 Pb int and 238 U int The backgrounds of the analysis were Bsl206, Bsl207 and Bsl238. The mass spectrometer detector accepts 206 Pb, 207 Pb, 208 Pb, 232 Th and 238 U times are Del206, Del207, Del208, Del232 and Del238 respectively. 238 U int <50 or 206 Pb int <25 data is row i (corresponding to the average count intensity and ), the following methods are used for background correction, outlier removal and interpolation:

[0085]

[0086]

[0087]

[0088] In the formula, Bsl206, Bsl207 and Bsl238 represent 206 Pb, 207 Pb and 238 U background value; 238 U intr Represents the value after background correction, outlier removal and interpolation processing. 238 U count; 207 Pb intr Represents the value after background correction, outlier removal and interpolation processing. 207 Pb count; 206 Pb intr Represents the value after background correction, outlier removal and interpolation processing. 207 Pb count; Time i Represents the analysis time of the i-th row of data; Represents row i of data 238 Average counting intensity of U; Represents row i of data 207 Average counting intensity of Pb; Represents row i of data 206 The average counting intensity of Pb; Figure 5 As shown, T c Represents the time required for one detection cycle of the detector, T s Represents the time difference between detectors scanning isotopes of different masses. There is the following relationship between Tc and Ts:

[0089] T s =T C -(Del206+Del207+Del208+Del232+Del238)*0.25 (13)

[0090] For the data that have completed background correction, outlier removal, and interpolation processing, the isotope composition and corresponding error are calculated using the following formula:

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] In the above formula: 238 U / 206 Pb represents the radioactivity of the sample 238 U / 206 Pb isotopic composition; 207 Pb / 206 Pb represents the radioactivity of the sample 207 Pb / 206 Pb isotope composition; Sig206, Sig207 and Sig238 represent 206 Pb, 207 Pb and 238 U counts correspond to the absolute error, 86 Err and 76 Err represents 238 U / 206 Pb and 207 Pb / 206 The error of Pb value; T68 and T75 represent 206 Pb / 238 U and 207 Pb / 235 U isotope pattern age. The calculation results are as follows Figure 6 shown.

[0101] 5. Calculation of mineral isotope age and drawing of isotope spatial distribution map

[0102] The ages of hydrothermal accessory minerals can be calculated using the Tera-Wasserburg diagram ( Figure 7 )、Wetherill diagram( Figure 8 ) or Bayesian regression ( Fig. 9 ) method. According to the list file, the spatial coordinates (X, Y) of each analysis point are obtained, and the above isotope processing results and position information are matched to draw the spatial distribution map of U-Pb isotopes or ages ( Fig.10 ).

[0103] 6. LA-ICP-MS Apatite Line Scanning U-Pb Dating Data Processing

[0104] Agilent 7900ICP-MS and Reso 193nm ArF laser are connected to form a LA-ICP-MS analysis system with a beam spot diameter of 60μm, a speed of 15μm / s, and an energy of 4J / cm 2, frequency 10Hz. NIST614 and MAD1 are used for instrument drift correction and isotope mass fractionation correction. MAD1 Bayesian regression method obtains an age of 486.4+6.3 / -14.0Ma (N=115, MSWD=2.42, Fig. 9 a), Tera-Wasserburg diagram regression obtained 487.2±5.6Ma ( Fig. 9 b). The age of BRZ-1 obtained by Bayesian regression is 2066.4±20Ma (N=114, MSWD=2.8, Fig. 9 c) Tera-Wasserburg diagram regression obtained 2073±17Ma (MSWD=2.1;n=114, Fig. 9 d). The age of MAD1 obtained by Thomson et al. (2012) using ID-TIMS is 486.6±0.9Ma. The age of BRZ-1 obtained by Apen et al. (2022) using ID-TIMS is 2078±12Ma. Therefore, the experimental results obtained in this invention are consistent with the recommended age error range of the standard material.

[0105] 7. Research results.

[0106] The present invention studies in detail the use of the age determination method to deduct common lead from accessory mineral standard materials, and correctly calculates the fractionation coefficient, and proposes a new method for high-resolution isotope calculation processing of LA-ICP-MS line scanning dating data. The LA-ICP-MS apatite line scanning U-Pb dating data was processed by this method, the verification of the monitoring standard sample was achieved, and the correct age result was obtained. The results show that this method can effectively process the LA-ICP-MS high-common lead hydrothermal accessory mineral U-Pb dating data, and is practical in the U-Pb isotope dating of hydrothermal accessory minerals.

Claims

1. A data processing method for line scanning U-Pb dating of high-common lead hydrothermal accessory minerals, characterized by: The processing steps are as follows: Step 1: Use the age determination method to deduct the common lead from the matrix-matched hydrothermal accessory mineral dating standard material, and calculate the U-Pb isotope fractionation coefficient in the analysis test; Step 2: Complete the matching of mass spectrum files and laser log files, realize the segmentation of continuous mass spectrum data, extract the analysis sequence, background and integration time, and analysis point spatial coordinates; Step 3: Perform background correction, outlier removal, interpolation processing, and isotope content and ratio calculation on the completed matching mass spectrum data; Step 4: Use the extracted sequence spatial information and multiple line scan mass spectrometry data to match and plot the isotope content, ratio, and age spatial distribution map; The definition of line scan U-Pb dating data of high-common lead hydrothermal accessory minerals is: using the analysis system composed of laser ablation system and inductively coupled plasma mass spectrometer, namely LA-ICP-MS, to perform line scan U-Pb isotope determination of high-common lead hydrothermal accessory minerals, and obtain the mass spectrum data and laser log files; The mass spectrum data at least includes the time Time={T1,T2,T3,…,T n }; Isotope count intensity 206 Pb int ={ 206 Pb1, 206 Pb2, 206 Pb3,… 206 Pb n }, 207 Pb int ={ 207 Pb1, 207 Pb2, 207 Pb3,…, 207 Pb n }and 238 U int ={ 238 U1, 238 U2, 238 U3,…, 238 U n }; Where: Time represents the time series; T n Represents the detection time of the nth mass spectrum data; 206 Pb int , 207 Pb int and 238 U int Respectively represent 206 Pb, 207 Pb and 238 U average counting intensity; 206 Pb n , 207 Pb n , 238 U n Represents the nth mass spectrum data 206 Pb, 207 Pb and 238 U average counting intensity; The laser log file contains a csv file automatically generated when the laser analyzes the sample sequence, which contains the timestamp, sample name, laser status, and spatial coordinates (X, Y) of the analysis point; In the first step, the age determination method is used to perform ordinary lead deduction on the matrix-matched hydrothermal accessory mineral dating standard material containing ordinary lead. The specific definition is: ordinary lead mixing makes the Pb isotope composition of the standard material test contain radioactive lead and ordinary lead. Before the isotope fractionation calculation of the standard material is performed, it is necessary to perform a reasonable deduction calculation on the ordinary lead therein; When the dating standard material was first formed, there was no common lead mixed in. 206 Pb / 238 U and 207 Pb / 235 U age remains consistent with the Concord line. After reasonable deduction of common lead, the dating standard material falls near the Concord line on the Tera-Wasserburg diagram or the Wetherill diagram; According to the Stacey-Kramers crustal Pb evolution model, the relationship between common lead, radiogenic lead and measured lead isotopic compositions is as follows: In the above formula: and represents the common lead composition of the standard material; and Represents the radioactive lead isotopic composition of the standard material; 207 Pb m , 206 Pb m It is a standard substance for mass spectrometer testing 207 Pb and 206 The average counting intensity of Pb; 204 Pb c Representative of ordinary lead 204 Pb theoretical value; e is a natural constant; t represents the age of the standard substance; λ235 and λ238 represent 235 U and 238 U decay constant; r represents radioactive U-Pb isotope; c represents non-radioactive U-Pb isotope; m represents the actual measured value; By solving equations (1) to (6), the radioactive U-Pb isotope of the standard substance ordinary lead after deduction is obtained: In the formula represents the isotopic composition of lead of radiogenic origin; 206 Pb m and 207 Pb m , 238 U m Representative standard substances 206 Pb, 207 Pb and 238 The measured average counting intensity of the U isotope; Using formulas (6) and (7), the U-Pb isotopic composition of the standard material after deducting common lead is calculated; The U-Pb isotope fractionation coefficient in step 1 is expressed as: In the above formula, Corr76 and Corr86 represent 207 Pb / 206 Pb and 238 U / 206 Fractionation coefficient of Pb; Representative standard material after calibration radioactivity 207 Pb / 206 Pb composition; Representative standard material after calibration radioactivity 206 Pb / 238 U composition; Represents the theoretical calculation based on the age of the standard sample 207 Pb / 206 Pb value; Represents the theoretical calculation based on the age of the standard sample 206 Pb / 238 U value; The continuous mass spectrometry data segmentation in step 2 means: for the continuously acquired time series data, the sample sequence, laser state and position information are matched according to the laser log file, and the data is segmented into the file format of each individual sample, and a list file containing the file name, sample name, laser start and end lines, and position coordinates is generated; Step 3: Perform background correction, outlier removal, interpolation, and isotope content and ratio calculation on the completed mass spectrum data. The method is as follows: The specific method of background correction is as follows: the U-Pb isotope count intensity obtained by mass spectrometry analysis of the sample 206 Pb int , 207 Pb int and 238 U int , minus the corresponding instrument backgrounds Bsl206, Bsl207 and Bsl238; The specific method of outlier elimination is as follows: the U and Pb data obtained by mass spectrometry analysis that are below the instrument detection limit are eliminated; The specific method of interpolation processing is: for data where U and Pb are less than the critical set value, interpolation processing is performed based on the overall change trend of the previous and next data; the mass spectrometer detector accepts 206 Pb, 207 Pb, 208 Pb, 232 Th and 238 The U times are Del206, Del207, Del208, Del232 and Del238 respectively. 238 U int <50 or 206 Pb int If <25 data is i rows, the following method is used for interpolation: In the formula, Bsl206, Bsl207 and Bsl238 represent 206 Pb, 207 Pb and 238 U background value; 238 Uintr Represents the value after background correction, outlier removal and interpolation processing. 238 U count; 207 Pbintr It means the value after background correction, outlier removal and interpolation. 207 Pb count; 206 Pbintr It means the value after background correction, outlier removal and interpolation. 207 Pb count; Represents row i of data 238 Average counting intensity of U; Represents row i of data 207 Average counting intensity of Pb; Represents i-1 row of data 238 Average counting intensity of U; Represents i-1 row of data 207 Average counting intensity of Pb; Represents i-1 row of data 206 Average counting intensity of Pb; Timei Represents the analysis time of the i-th row of data; Time i-1 represents the analysis time of the i-1th row of data; T c Represents the time required for one detection cycle of the detector, T s Represents the time difference between detectors scanning isotopes of different masses; there is the following relationship between Tc and Ts: T s =T C -(Del206+Del207+Del208+Del232+Del238)*0.25 (13) For the data that have completed background correction, outlier removal, and interpolation processing, the isotope composition and corresponding error are calculated using the following formula: In the above formula: 238 U / 206 Pb represents the radioactivity of the sample 238 U / 206 Pb isotopic composition; 207 Pb / 206 Pb represents the radioactivity of the sample 207 Pb / 206 Pb isotope composition; Sig206, Sig207 and Sig238 represent 206 Pb, 207 Pb and 238 U counts correspond to the absolute error, 86 Err and 76 Err represents 238 U / 206 Pb and 207 Pb / 206 Error in Pb value.

2. The method for processing line scanning U-Pb dating data of high common lead hydrothermal accessory minerals according to claim 1 is characterized by: Step 4: Draw the spatial distribution map of isotope content, ratio and age. The method is as follows: the age of hydrothermal accessory minerals can be obtained using the Tera-Wasserburg diagram, Wetherill diagram or Bayesian regression method; obtain the spatial coordinates (X, Y) of each analysis point according to the list file, match the above isotope processing results and position information, and draw the spatial distribution map of U-Pb isotopes or ages.

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