Carbonate U-Pb dating method and device

Abstract

The invention discloses a carbonate U-Pb dating method and device, and the method comprises the steps: determining a carbonate to-be-detected region formed in a single period according to lithofacies and cathode luminescence results; performing line scanning analysis in the carbonate to-be-detected area, and determining a first area of the U content and the U / Pb ratio; performing surface scanning analysis in the first area to obtain surface scanning data; the surface scanning data are calculated, and the ratio of 208Pb / 238U to 207Pb / 235U is obtained; and screening and recombining the ratio data of the 208Pb / 238U and the 207Pb / 235U, and determining the age of the carbonate U-Pb.

Description

Technical Field

[0001] This article relates to the field of geological exploration evaluation and geochronology technology, and in particular to a method and device for carbonate U-Pb dating. Background Art

[0002] Isotope geochronology is a fundamental discipline for exploring the spatiotemporal evolution and dynamic processes of the Earth. Among these, the most widely used dating technique is LA-ICP-MS U-Pb dating of accessory minerals. Compared to methods such as ID-TIMS and SIMS, it offers advantages such as high efficiency and low cost. The scope of research has expanded from zircon to rutile, apatite, monazite, titanite, cassiterite, and calcite. Calcite and dolomite, as direct products of fluid activity, are widely distributed within sandstones, mudstones, and carbonate formations in oil and gas basins, recording the various fluid events experienced within the basins. Geochronological analysis of these minerals can accurately determine the history and evolution of fluid activity within the basins, holding enormous potential for application in petroleum geology. Currently, LA-ICP-MS U-Pb dating primarily relies on point analysis techniques. However, due to the generally low U content in carbonates and the high and uneven distribution of common lead, stringent instrument sensitivity and target selection requirements have limited the widespread application of carbonate U-Pb dating. Summary of the Invention

[0003] In response to the above problems, the present application provides a method for U-Pb dating of carbonates. This method extracts measurement data of different U / Pb ratios with small errors and data dispersion through single-surface scanning element imaging analysis, and can accurately perform common lead correction and regression analysis to obtain reliable and accurate mineral ages.

[0004] In a first aspect, the present application provides a method for U-Pb dating of carbonates, the method comprising:

[0005] Based on petrographic and cathodoluminescence results, determine the carbonate testing area formed in a single period;

[0006] Performing line scanning analysis in the carbonate test area to determine the first area of ​​U content and U / Pb ratio;

[0007] Performing surface scanning processing on the first area to obtain surface scanning data;

[0008] Calculate the surface scanning data to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio;

[0009] Regarding the 208 Pb / 238 U and 207 Pb / 235 The U ratio data were screened and recombined to determine the carbonate U-Pb age.

[0010] In a second aspect, an embodiment of the present invention further provides a carbonate U-Pb dating device, comprising:

[0011] A memory and a processor; the memory is used to store a program for determining the U-Pb dating of carbonates, and the processor is used to read and execute the program for determining the U-Pb dating of carbonates, and perform any one of the methods described in the above embodiments.

[0012] In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium having a data processing program stored thereon, and the data processing program is executed by a processor to perform the method for determining carbonate U-Pb dating according to any one of the above embodiments.

[0013] Compared with the related art, the present application provides a method and apparatus for U-Pb dating of carbonates, the method comprising: determining a carbonate test area formed in a single period based on petrography and cathodoluminescence results; performing line scanning analysis within the carbonate test area to determine a first area of ​​U content and U / Pb ratio; performing surface scanning processing in the first area to obtain surface scanning data; and calculating the surface scanning data to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio; 208 Pb / 238 U and 207 Pb / 235 U-ratio data is screened and recombined to determine carbonate U-Pb ages. This application only requires a single surface scanning elemental imaging analysis to rapidly extract measurement data for different U / Pb ratios with minimal error directly from the imaging data. This also avoids the interference of deep fractionation encountered during point analysis, enabling accurate common lead correction and regression analysis to obtain reliable and precise mineral ages.

[0014] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. Other advantages of the present application can be realized and obtained by the solutions described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0016] Figure 1 This is a flow chart of a method for directly performing U-Pb dating of carbonates based on elemental imaging data according to an embodiment of the present application;

[0017] Figure 2 Schematic diagram of a device for directly performing U-Pb dating of carbonates based on element imaging data according to an embodiment of the present application;

[0018] Figure 3 Schematic diagram of direct carbonate U-Pb dating based on elemental imaging data in some exemplary embodiments;

[0019] Figure 4 Graphs showing the results of surface scanning imaging and U-Pb direct dating of a Permian limestone sample from a well in a certain basin in some exemplary embodiments. DETAILED DESCRIPTION

[0020] This application describes multiple embodiments, but this description is exemplary rather than restrictive, and it will be apparent to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described herein. Although many possible feature combinations are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0021] This application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive solution defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other inventive solutions to form another unique inventive solution defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the appended claims and their equivalents, the embodiments are not subject to other limitations. In addition, various modifications and changes may be made within the scope of protection of the appended claims.

[0022] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps in the specific order described. As will be understood by those skilled in the art, other orders of steps are also possible. Therefore, the specific order of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that these orders can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0023] The inventors discovered that:

[0024] Currently, laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) is the primary point analysis technique used for U-Pb dating. However, due to the generally low U content in carbonates and the high and uneven distribution of common lead, high instrument sensitivity and target selection requirements are required, limiting the widespread application of carbonate U-Pb dating.

[0025] Point analysis of common lead carbonate minerals by LA-ICP-MS presents the following challenges: 1. With increasing single-point depth, the mass spectrometric signal decreases rapidly, resulting in depth fractionation of isotope ratios, making correction difficult. Furthermore, due to differences in lithology, composition, grain size, and crystal structure among calcite and dolomite samples, laser ablation efficiency varies significantly. In particular, the ablation efficiency of calcite, dolomite, and aragonite can differ significantly. This results in significant variations in the depth of the resulting ablation pits, even when using the same beam spot size and laser frequency. These varying depth-to-width ratios of ablation pits can cause deep pit fractionation and / or matrix effects between the sample and the standard, leading to biases in U-Pb dating data. While this bias cannot be corrected for, it cannot be ignored and is directly impacting the accuracy and reliability of the dating data. 2. Due to the depth heterogeneity of common lead perpendicular to the sample surface, it is difficult to distinguish whether the variation in single-point isotope ratios with depth in the sample under analysis is due to depth fractionation or the effects of uneven common lead distribution. ③ If the point analysis is performed improperly, resulting in the measurement data not being dispersed across the TW diagram but instead being concentrated somewhere within the diagram, particularly near the upper intersection, this can lead to regression age calculation failure or high uncertainty. ④ Carbonate minerals often exhibit multi-stage growth characteristics and are susceptible to later diagenetic secondary transformations. Since the single-point method cannot effectively identify these characteristics when placing points, the results of the single-point method test may reflect mixed ages, making the geological significance of the age results unclear.

[0026] While LA-ICP-MS surface scanning can rapidly obtain information on elemental and isotope ratios and their distribution variations on mineral surfaces, the short time and poor accuracy of single LA-ICP-MS measurements make direct dating of these data unsuitable. To achieve more accurate carbonate U-Pb dating results, some researchers have proposed a carbonate U-Pb dating technique guided by LA-ICP-MS surface scanning imaging. This technique first performs LA-ICP-MS surface scanning elemental imaging to identify regions of high U and high U / Pb ratios. Once these high-U regions are identified, denudation points are identified and a single-point analysis is performed. While this method can yield relatively reliable age results, it suffers from long experimental cycles, low efficiency, and high economic costs, making it unsuitable for widespread application.

[0027] The present invention provides a method for U-Pb dating of carbonates. Figure 1 As shown, the method includes steps S100-S140:

[0028] S100: Determine the carbonate testing area formed in a single phase based on petrographic and cathodoluminescence results;

[0029] S110: Identifying a first region of U content and U / Pb ratio within the carbonate test region;

[0030] S120: performing LA-ICP-MS surface scanning analysis on the first region to obtain surface scanning data;

[0031] S130: Calculate based on the surface scanning data to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio;

[0032] S140: 208 Pb / 238 U and 207 Pb / 235 The U ratio data were screened and recombined to determine the carbonate U-Pb age.

[0033] In this embodiment, since carbonate veins or cements usually grow in multiple stages, the formation time, optical characteristics, and trace element characteristics of cements in different stages are not the same, and they are easily affected by later diagenetic replacement. Therefore, it is necessary to use the results of petrography and cathode luminescence observations to divide the diagenetic sequence. If conditions permit, charge imaging, backscattered electron imaging (BSE) and X-ray fluorescence spectroscopy (XRF) imaging results should also be combined for auxiliary identification to determine the carbonate test area formed in a single stage.

[0034] In an exemplary embodiment, identifying a first region of U content and U / Pb ratio within the carbonate test region includes:

[0035] The first step is to perform element content correction on the line scan data to obtain 238 U content, 238 U / 206 Pb ratio;

[0036] The second step is based on the U content, 238 U / 206 The Pb ratio determines the area that meets the predetermined conditions as the first area. 238 U / 206 The Pb ratio data can be used to directly determine the distribution of high-value areas on the erosion line using the grayscale value, such as Figure 3 As shown, Figure 3 The middle figure is a relatively high-value area obtained based on the line scan. The area in the relatively high-value area is used as the optimal area for surface scanning analysis, that is, the first area. The LA-ICP-MS surface scanning experiment is performed based on the first area.

[0037] In an exemplary embodiment, the process of line scanning data is as follows:

[0038] The first step is to set an erosion line in the area to be measured along the direction perpendicular to the growth ring or parallel to the long axis;

[0039] The second step is to set the corresponding experimental parameters and use the peak-hopping method to perform LA-ICP-MS line scanning to detect the signal intensity of the elements;

[0040] The experimental parameters include: laser spot size of 90 μm, scanning speed of 20 μm / s, frequency of 10 Hz, laser power of 2 J / cm 2 .

[0041] In this embodiment, due to the strong heterogeneity of the distribution of U and Pb contents in carbonate minerals, randomly selecting an area in the area to be tested for surface scanning imaging analysis may not select an area with relatively high U content and U / Pb ratio, and thus cannot obtain ideal dating results. An ablation line is set in the area to be tested along the direction perpendicular to the growth ring or parallel to the long axis to perform LA-ICP-MS line scanning analysis. Due to the low U and Pb contents in carbonates, conventional quadrupole ICP-MS is not sensitive enough. Except for individual samples with high U and Pb contents, in this embodiment, high-resolution SF-ICP-MS is required to ensure the accuracy of the analysis. Therefore, this embodiment uses a 193nm excimer laser ablation system in combination with SF-ICP-MS for LA-ICP-MS analysis. Introducing a small amount of N2 into the Ar carrier gas can further improve the sensitivity of the instrument. The experimental parameters for line scanning analysis are set as follows: Peak jumping mode is used for detection 24 Mg, 43 Ca, 55 Mn, 57 Fe, 71 Ga, 85 Rb, 88 Sr. 90 Zr, 137 Ba, 140 Ce, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th, 238 U signal intensity. Laser spot size is 90 μm, scanning speed is 20 μm / s, frequency is 10 Hz, and laser power is 2 J / cm 2 The line scan data were grouped and defined, and trace element data were processed using Trace Element DRS. The distribution of U content, U / Pb ratio, and other values ​​along the erosion line were obtained in the Imaging module. The sections with relatively high U content and U / Pb ratio were identified, and the areas adjacent to the high-value sections of the erosion line were used as target areas for surface scanning imaging analysis.

[0042] In an exemplary embodiment, performing surface scanning processing on the first area to obtain surface scanning data includes:

[0043] In the first area, setting corresponding surface scanning parameters to perform surface scanning;

[0044] Determine the surface scan data of relevant elements;

[0045] The surface scanning data is data on changes in the intensity of detected element signals over time;

[0046] The detection elements include:24 Mg, 43 Ca, 55 Mn, 57 Fe, 71 Ga, 85 Rb, 88 Sr. 90 Zr, 137 Ba, 140 Ce, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th, 238 U.

[0047] The corresponding surface scanning parameters were set for surface scanning, including: the total analysis time for each line was 136 s, including 8 s of laser warm-up time, 108 s of laser ablation time, 20 s of purge time, 118 s of mass spectrometry end data acquisition time, a scanning line length of approximately 0.2 cm, a spot size of 90 μm, a scanning speed of 20 μm / s, a frequency of 10 Hz, and a laser power of 2 J / cm 2 .

[0048] In an exemplary embodiment, the surface scan data is calculated to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio, including:

[0049] The first step is to group and define the surface scan data;

[0050] Wherein, each set of data corresponds one-to-one to the sample information;

[0051] In this step, the scanning analysis sequence is completed using WC-1 (calcite U-Pb dating standard), NIST614 (element standard), sample1, sample2, ...sample10, NIST614, and WC-1. This allows the NIST614 standard to correct for elemental fractionation effects, and the WC-1 standard to correct the U / Pb ratio to obtain accurate U-Pb ages. Because the raw data does not contain sample information, data processing requires grouping and defining the raw data according to WC-1, NIST614, sample, and baselines, ensuring that each data group has sample information.

[0052] The second step is to use NIST614 data to calibrate the element content of each set of sample surface scanning data;

[0053] Step 3: Calculate based on the corrected surface scan data 208 Pb / 238 U and 207 Pb / 235 U ratio.

[0054] In an exemplary embodiment, the 208 Pb / 238 U and 207 Pb / 235 U ratio data are screened and recombined to determine carbonate U-Pb ages, including:

[0055] The first step is to 208 Pb / 238 U and 207 Pb / 235 The U ratio data is screened to determine a second region; wherein the second region is a region of interest.

[0056] Step 2: Based on 208 Pb / 238 U and 207 Pb / 235 U ratio data, sampling pixel point data in the region of interest to obtain virtual data points;

[0057] The third step is to obtain the TW diagram based on the virtual data points and calculate the U-Pb age. In the third step, the full name of the TW diagram is the Tera-Wasserburg diagram, which is based on 238 U / 206 Pb, 207 Pb / 206 Pb data and error data. The error data is the standard deviation. Each data point on the graph actually consists of a period of test data, from which the average and standard deviation can be calculated. By plotting a TW diagram, the age at the lower intersection of the fitted line and the TW diagram can be calculated. This age is the U-Pb age for the sample.

[0058] In an exemplary embodiment, the process of determining the second area is:

[0059] The first step is to eliminate points that have undergone secondary transformation and contain abnormal data through pre-set element screening criteria;

[0060] The second step is to use the eliminated data points to determine the second area, namely the area of ​​interest.

[0061] In this embodiment, by setting appropriate element screening criteria, such as Rb<0.5ppm, Th<0.5ppm, Mg / Ca<0.004; the screening criteria are used to eliminate points that have undergone secondary transformation and contain abnormal data, that is, data points that do not meet the conditional criteria are not selected to generate the region of interest ROI, i.e., the second area.

[0062] In an exemplary embodiment, the 208 Pb / 238 U and 207 Pb / 235 U ratio data, sampling the pixel data in the area of ​​interest to obtain virtual data points, including:

[0063] The first step is based on 208 Pb / 238 U and 207 Pb / 235 U ratio data, using the empirical cumulative distribution function to segment the pixel data in the region of interest according to the numerical value interval, and resample and combine;

[0064] In this embodiment, based on 208 Pb / 238 U and 207 Pb / 235 For U ratio data, the empirical cumulative distribution function (ECDF) is used to resample and combine the ROI pixel data into segments according to the Pb / U ratio range, generating 30-60 groups of virtual data points. The Empirical Cumulative Distribution Function (ECDF) is a statistical tool used to visualize data distribution. For a given dataset, the ECDF calculation steps are as follows: 1. Determine the value of the segmented statistics. For example, if the range is 0-100 and the statistics are determined to be divided into 10 segments, the segmented statistics will have values ​​of 10, 20, and so on. 2. For each observation, determine the number of observations less than or equal to the statistical value. 3. Divide this number by the total number of observations in the dataset to obtain the cumulative distribution percentage corresponding to the statistical value.

[0065] The second step is to generate multiple sets of virtual data points.

[0066] In this step, virtual data points are created by recombining and sampling the original data. These points differ significantly from the original data points. Original data points are typically grouped in chronological order, such as calculating data from 1-5 seconds as one data point and 5-10 seconds as another. Recombining and sampling breaks this chronological order, combining data from different times into a single new data point, referred to here as a virtual data point.

[0067] In a second aspect, an embodiment of the present invention further provides a carbonate U-Pb dating device, such as Figure 2 As shown, the device includes: a memory 200 and a processor 210; the memory is used to store a program for carbonate U-Pb dating, and the processor is used to read and execute the program for carbonate U-Pb dating, and perform any one of the methods described in the above embodiments.

[0068] In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium having a data processing program stored thereon, and the data processing program is executed by a processor to perform the carbonate U-Pb dating method described in any one of the above embodiments.

[0069] The direct dating method based on elemental surface scanning imaging data provided by this invention has the following significant advantages: First, it avoids the depth fractionation effect present in single-point denudation analysis; second, it avoids the pre-screening and site selection process, improving analysis efficiency; third, this method generates distribution maps of different elemental contents, which facilitates identification of sample period and origin and the elimination of anomalous inclusion data, thus clarifying the geological significance of the age results; and fourth, it significantly improves the accuracy and precision of U-Pb dating results. The method provided by this invention is also applicable to the accurate U-Pb dating of other common lead accessory minerals.

[0070] Example 1

[0071] To achieve the above objectives, the present invention provides a method for direct U-Pb dating of carbonates based on elemental imaging data, which comprises the following steps:

[0072] Step S1: Determine the carbonate test area formed in a single phase based on petrographic and cathodoluminescence results.

[0073] Step S2: setting an ablation line in the area to be tested along the direction perpendicular to the growth ring or parallel to the long axis to perform LA-ICP-MS line scanning analysis to identify the area with relatively high U content and U / Pb ratio, i.e., the first area.

[0074] Step S3, set the scanning area in the first area with high U content and U / Pb ratio, and conduct LA-ICP-MS surface scanning experiment: select the area to be tested, determine the line length and number according to the size of the area to be tested, and set 8 lines each for NIST614, WC-1 and laboratory internal standard according to the line length of the sample to be tested, and 4 lines before and after the sample to be tested. The surface scanning analysis experiment parameters are set as follows: use the peak jumping method to detect 24 Mg, 43 Ca, 55 Mn, 57 Fe, 71 Ga,85 Rb, 88 Sr. 90 Zr, 137 Ba, 140 Ce, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th, 238 U signal intensity, the total analysis time for each analysis line is 136s, including 8s laser warm-up time, 108s laser ablation time, 20s purge time, and 118s mass spectrometer data acquisition time. The scan line length is about 0.2cm, the spot size is 90μm, the scan speed is 20μm / s, the laser frequency is 10Hz, and the laser power is 2J / cm 2 .

[0075] Step S4: grouping and defining the surface scan data;

[0076] Step S5: first use Trace Element DRS to process trace element data;

[0077] Step S6: Process the U-Pb dating data using the U-Pb Geochronology DRS.

[0078] Step S7: Calculate based on the result data 208 Pb / 238 U and 207 Pb / 235 U ratio;

[0079] Step S8: using element discrimination criteria to eliminate areas where secondary transformation has occurred or where abnormal data is present, thereby generating a second area, namely, a region of interest (ROI);

[0080] Step S9: Based on 208 Pb / 238 U and 207 Pb / 235 For the U ratio data, the empirical cumulative distribution function (ECDF) is used to resample and combine the ROI pixel data according to the numerical range of the Pb / U ratio to generate 30-60 groups of virtual data points;

[0081] Step S10: Draw a TW diagram with the generated virtual data points to calculate the accurate U-Pb age and initial lead composition.

[0082] Compared with the prior art, the present invention has the following beneficial effects:

[0083] 1. Direct dating based on elemental surface scanning imaging data avoids the depth fractionation effect found in single-point ablation analysis. Because elemental surface scanning does not involve depth fractionation, both matrix effects and fractionation effects are greatly reduced, resulting in more accurate U-Pb dating results.

[0084] 2. Direct dating based on elemental surface scanning imaging data avoids complex pre-screening and site selection processes, improving analysis efficiency and saving time and money. Traditional grid-based screening methods are time-consuming and sample-intensive. Dating methods guided by surface scanning data require re-pointing based on elemental imaging results to select areas with high U content and low common lead content, and then perform single-point analysis, which wastes time and money. This method, however, achieves U-Pb dating with a single elemental imaging step, significantly saving time and money.

[0085] 3. This method can obtain distribution maps of different element contents, which helps to identify the sample period and origin and eliminate abnormal data such as inclusions, making the geological significance of the age results clearer.

[0086] 4. A prerequisite for accurate carbonate U-Pb dating is the accuracy of the data points. 238 U / 206 The Pb ratios are sufficiently dispersed on the TW diagram age lines, resulting in relatively accurate fitting lines and small intersection ages. Compared to traditional single-point denudation methods, direct dating based on elemental surface scanning imaging data significantly improves the accuracy of age results. This is because this method, by resampling a large amount of data, can obtain virtual data points with maximized U / Pb ratio dispersion, thus fitting highly accurate ages, providing not only reliable lower intersection ages but also reliable initial lead compositions.

[0087] Example 2

[0088] The present invention provides a method for direct U-Pb dating of carbonates based on element imaging data. The schematic process is as follows: Figure 3 As shown, Figure 3 The left picture shows that an erosion line is set along the direction perpendicular to the growth ring or parallel to the long axis in the test area for LA-ICP-MS line scanning analysis. Figure 3 The middle figure in the figure is based on the line scan to identify the relatively high value areas of U content and U / Pb ratio; after identifying the relatively high value sections of U content and U / Pb ratio, Figure 3 The right figure shows that the scanning area is set in the area with high U content and U / Pb ratio, and the LA-ICP-MS surface scanning experiment is performed.

[0089] The method provided in this example was used to accurately determine the sedimentary age of the Permian limestone sample reservoir and the formation age of the calcite vein in the xxx well of the xx basin. The results showed that the age of the parent rock was about 249.6±3.3Ma, and the age of the vein was about 239±13Ma. Figure 4 It can be seen that the U / Pb ratio data obtained by this method have a high degree of dispersion on the fitting line, a good degree of fitting, and a greatly improved age precision and accuracy.

[0090] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As is well known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable, and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those skilled in the art that communication media generally embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for carbonate U-Pb dating, characterized in that: The method comprises: Based on petrographic and cathodoluminescence results, determine the carbonate testing area formed in a single period; Performing line scanning analysis in the carbonate test area to determine the first area of ​​U content and U / Pb ratio; Performing surface scanning processing on the first area to obtain surface scanning data; Calculate the surface scanning data to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio; Regarding the 208 Pb / 238 U and 207 Pb / 235 The U ratio data were screened and recombined to determine the carbonate U-Pb age.

2. The method for carbonate U-Pb dating according to claim 1, characterized in that: Before determining the first region of U content and U / Pb ratio in the carbonate test region, the method further includes: Setting an erosion line in the carbonate test area along a direction perpendicular to the growth ring or parallel to the long axis; Performing line scanning analysis on the ablation line to obtain line scanning data; The line scan data includes: 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th, 238 The signal strength of U.

3. The method for carbonate U-Pb dating according to claim 2, characterized in that: The line scanning analysis is performed in the carbonate test area to determine the U content and the U / Pb ratio in the first area, including: The line scan data is corrected for element content to obtain 238 U content, 238 U / 206 Pb ratio; According to the U content, 238 U / 206 The Pb ratio determines a region that meets a predetermined condition as the first region.

4. The method for carbonate U-Pb dating according to claim 1, characterized in that: The performing surface scanning processing on the first area to obtain surface scanning data includes: In the first area, setting corresponding surface scanning parameters to perform surface scanning; Determine the surface scan data of relevant elements; The surface scanning data is data on changes in the intensity of detected element signals over time; The detection elements include: 24 Mg, 43 Ca, 55 Mn, 57 Fe, 71 Ga, 85 Rb, 88 Sr. 90 Zr, 137 Ba, 140 Ce, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th, 238 U.

5. The method for carbonate U-Pb dating according to claim 4, characterized in that: The surface scanning data is calculated to obtain 208 Pb / 238 U and 207 Pb / 235 U ratio, including: Grouping and defining the surface scan data, wherein each group of data corresponds one-to-one to the sample information; The element content of each set of sample surface scanning data was corrected using NIST614 data; Calculated based on the corrected surface scan data 208 Pb / 238 U and 207 Pb / 235 U ratio.

6. The method for carbonate U-Pb dating according to claim 5, characterized in that: The above mentioned 208 Pb / 238 U and 207 Pb / 235 U ratio data are screened and recombined to determine carbonate U-Pb ages, including: Regarding the 208 Pb / 238 U and 207 Pb / 235 The U ratio data is screened to determine the second area; based on 208 Pb / 238 U and 207 Pb / 235 U ratio data, sampling pixel point data in the second area to obtain virtual data points; Based on the virtual data points, a TW diagram is obtained, and the U-Pb age is calculated.

7. The method for carbonate U-Pb dating according to claim 5, characterized in that: The process of determining the second area is: Through pre-set element screening criteria, points with secondary transformation and abnormal data are eliminated; The second region is determined using the eliminated data points.

8. The method for carbonate U-Pb dating according to claim 5, characterized in that: The based 208 Pb / 238 U and 207 Pb / 235 U ratio data, sampling pixel point data in the second area to obtain virtual data points, including: Based on the 208Pb / 238U and 207Pb / 235U ratio data, the empirical cumulative distribution function is used to segment the pixel data in the second area according to the numerical value interval, and resample and combine them; Generate multiple sets of virtual data points.

9. A device for carbonate U-Pb dating, characterized in that: The device includes: a memory and a processor; the memory is used to store data for carbonate U-Pb dating, and the processor is used to read and execute the program for processing carbonate U-Pb dating data, and perform the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a data processing program stored thereon, wherein the data processing program is executed by a processor to perform the method for U-Pb dating of carbonates according to any one of claims 1 to 8.

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