Quantitative sedimentary basin object source analysis method based on detrital zircon U-Pb age data

Abstract

The method is a quantitative sedimentary basin feature source analysis method based on detrital zircon U-Pb age data, results of quantitative analysis and cumulative age curve analysis of a multi-dimensional calibration method (MDS) are fully utilized, differences among different samples are compared more accurately, and the method has remarkable advantages in quantitative treatment of a large number of samples. The method comprises the following specific steps: (1) collecting and integrating U-Pb age data of chipping zircon from different studies, and preprocessing the U-Pb age data; (2) performing statistical analysis and visualization processing in various forms on the U-Pb age data of the chipping zircon; (3) analyzing the contribution rate of each zircon age to sample age interpretation, and quantitatively evaluating the importance of different zircon ages in material source analysis; (4) quantitatively comparing the similarities among the samples by adopting a multi-dimensional calibration method; and (5) analyzing the difference of different source-sink system construction backgrounds in the sedimentary basin by drawing a chipping zircon cumulative age curve and the difference distribution between the zircon crystallization age and the deposition age in the sediment, and further explaining the dynamic mechanism of the construction unit and the source-sink system on the periphery of the construction unit.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas geological exploration, and in particular relates to a method for using detrital zircon U-Pb age data to perform provenance analysis, source-sink system analysis, structural sedimentary differentiation identification and quantitative analysis of sedimentary basins. Background Art

[0002] Sedimentary basins are important places for surface processes on the earth. Their provenance characteristics are related to major geological issues such as crustal evolution, tectonic activities, and climate change. Therefore, the provenance analysis of sedimentary basins has always been one of the core topics in the field of geological science. However, the process of provenance analysis is often complex and challenging. In particular, when trying to explain complex geological phenomena such as tectonic sedimentary differentiation and source-sink system changes, traditional analytical methods often seem to be unable to cope with the problem.

[0003] Among the research methods of provenance analysis, detrital zircon U-Pb dating is an important geochronological method. It relies on the strong weathering resistance of zircon and rich geochemical information. It can effectively constrain the maximum sedimentary age of sediments and provide accurate provenance information. However, the amount of detrital zircon U-Pb dating data is huge and widely distributed. In the past twenty years, there have been millions or even more detrital zircon U-Pb dating data in the world alone, not including unpublished data. This poses a huge challenge to data processing and analysis. With the increase in the amount of data, the understanding of the provenance problem has become more in-depth, but the provenance problem has not become simpler due to the increase in the amount of data. On the contrary, it may become more complicated.

[0004] Usually, when conducting sediment source analysis, the statistical data of single-grain U-Pb age of detrital zircon is visualized and plotted into age spectra in different forms, such as histograms, probability density plots, kernel density estimates, and cumulative age distributions. However, these traditional visualization methods can only solve simple comparative analysis problems. For situations with a large number of samples and subtle differences, such as studying provenance tracing at a large spatial scale or high-resolution stratigraphic comparison, traditional methods are inadequate.

[0005] To solve this problem, researchers have introduced a variety of data analysis methods and software tools. For example, IsoplotR is a widely used geochronological data processing and analysis software, which can perform various forms of statistical analysis and visualization on detrital zircon U-Pb geochronology data, helping researchers to better understand and interpret the data. But even so, the interpretation and use of detrital zircon U-Pb geochronology data still faces many challenges. For example, how to accurately determine whether the provenance of different samples is consistent, how to quantitatively compare the similarities and differences of a large number of samples, and how to effectively use detrital zircon U-Pb geochronology data to solve complex geological problems such as tectonic sedimentary differentiation and source-sink system changes.

[0006] In this context, this paper proposes a new quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data. This method introduces new calculation methods and analysis strategies, fully utilizes the information of detrital zircon U-Pb chronology data, can better solve the above problems, and has important theoretical significance and practical value. Summary of the invention

[0007] The present invention provides a quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data, which can more accurately compare the differences between different samples, especially has significant advantages in quantitatively processing a large number of samples, thereby providing a more scientific and accurate analysis tool for complex sedimentary basin provenance problems.

[0008] To achieve the above object, the present invention provides the following technical solutions: The present invention proposes a quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data and its application, which mainly includes the following steps: Step S1, collect and integrate detrital zircon U-Pb age data from different studies, and preprocess the data.

[0009] Step S2: Use software such as IsoplotR to perform various forms of statistical analysis and visualization on the detrital zircon U-Pb age data.

[0010] Step S3: Analyze in detail the contribution of each zircon age to the sample age interpretation, and quantitatively evaluate the importance of different zircon ages in provenance analysis.

[0011] Step S4: Use multidimensional calibration (MDS) to quantitatively compare the similarities between samples and display the relative differences between samples in the form of points in multidimensional space.

[0012] Step S5, using the empirical cumulative distribution function (CAD) to draw the probability curve of the cumulative age of detrital zircon, and combining the difference characteristics between the zircon crystallization age and the deposition age in the sediments to analyze the differences in the tectonic background of different source-sink systems in the sedimentary basins, and further explain the dynamic mechanism of the tectonic unit and its surrounding "source-sink system".

[0013] The patent of this invention provides a quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data, and its advantages are mainly reflected in the following three aspects: First, the improvement of accuracy and quantitative analysis capabilities: Traditional provenance analysis methods mainly rely on qualitative comparison and visual analysis, which are easily affected by subjective judgment and difficult to handle small differences between a large number of samples. This invention achieves a leap from qualitative to quantitative by introducing multidimensional calibration (MDS) and calculation of zircon age contribution rate. This method not only improves the accuracy of analysis, but also can accurately measure and compare the differences between different samples, especially when dealing with large data sets, thus providing a more scientific and accurate analysis tool for complex sedimentary basin provenance issues.

[0014] Second, simplification and efficiency of complex data processing: In the application of detrital zircon U-Pb chronology data, the huge amount of data and complex information are a common challenge. The present invention can quickly integrate and analyze detrital zircon U-Pb data from different sources through efficient data processing processes and algorithm optimization. The use of advanced software tools such as IsoplotR, combined with the quantitative analysis method in the invention, significantly improves the efficiency of data processing and the reliability of results, allowing researchers to obtain more in-depth and comprehensive research results in a shorter period of time.

[0015] Third, the breadth and flexibility of application: The present invention is not only applicable to provenance analysis in the fields of sedimentology and geochemistry, but can also be extended to other studies that require detailed analysis of the sources of geological samples, such as paleoenvironmental reconstruction, paleoclimate analysis, etc. Multidimensional Scaling (MDS) provides an intuitive and scientific way to express the relationship between complex samples, allowing the present invention to be flexibly applied to a variety of different scientific problems and research backgrounds, enhancing its universality and practical value.

[0016] Through these advantages, the present invention can effectively improve the scientificity and practicality of sedimentary basin provenance analysis, and bring innovative tools and methods to geological science research and related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 : Technology roadmap.

[0018] Attached Figure 2: Relative probability density map of detrital zircon and statistical analysis and visualization processing of detrital zircon U-Pb age data.

[0019] Attached Figure 3 : Multidimensional Scaling (MDS) bitmap.

[0020] Attached Figure 4 : Schematic diagram of the cumulative age probability curve combined with the tectonic background and cumulative age probability curve. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is as follows: ⑴ Collect detrital zircon U-Pb age data in the study area, preliminarily process the data, calculate the zircon concordance, screen out zircon samples with a concordance of 90%-110%, and select appropriate ratios based on the age values ​​of zircon samples. When the age value of the zircon sample is greater than or equal to 1000Ma, use the 207Pb / 206Pb and 206Pb / 238U ratios. When the age value is less than 1000Ma, use the 207Pb / 235U and 206Pb / 238U ratios. (2) Visualize the detrital zircon U-Pb age data using IsoplotR and other software to obtain the probability density map and intuitively obtain the detrital zircon age distribution information; ⑶ According to the age distribution of detrital zircons in the obtained probability density map, the contribution rate of each zircon age to the sample is analyzed to determine the age characteristics of the sample, and the source of the detrital material is preliminarily determined in combination with the local geological data of the study area; (4) Based on the preliminary judgment of the source of detrital materials, the similarities and differences between samples were further quantitatively compared based on the two-dimensional calibration method of detrital zircon. The IsoplotR software was used to convert the detrital age distribution in the study area into a more intuitive MDS type map by utilizing its Dmax value based on the KS test or the Vmax value based on the Kuiper test. This map closely clusters similar samples together, and different samples are scattered, showing a certain distance, and roughly different regions are differentiated. Within or between regions, the map connects samples with high similarity with solid lines, and samples with low correlation with dotted lines, intuitively showing the degree of similarity of different samples. The samples were grouped according to the differentiated regions combined with the preliminary judged provenance information, and multiple samples with high similarity were comprehensively analyzed, and samples with high differences were analyzed separately to further determine the provenance information of the samples.

[0022] ⑸ Using the empirical cumulative distribution function (CAD), the age ranking of detrital zircon is set according to the numerical value of the age, and the cumulative age probability map of the study area is obtained (the horizontal axis is the zircon age value, and the vertical axis is the cumulative probability of the zircon age). The three tectonic backgrounds of the sedimentary period are divided according to the difference between the detrital zircon crystallization age (CA) and the stratigraphic depositional age (DA): convergent orogeny, collision compression and extension. These three backgrounds are combined to determine the tectonic background areas where the detrital zircon samples in different regions are located, and further explain the dynamic mechanism of the tectonic unit and its peripheral "source-sink system".

[0023] In order to more clearly express the technical advantages of the present invention, the embodiments of the present invention are further described in detail in conjunction with the accompanying drawings. Figure 1 This is the technical roadmap of the present invention, which shows the method of using the technology of the present invention to conduct quantitative sedimentary basin provenance analysis based on detrital zircon U-Pb age data. This technical route can more intuitively and accurately compare the differences between different samples, and further provide a more scientific and accurate analysis tool for complex sedimentary basin provenance issues.

[0024] Figure 2 The relative probability density map of detrital zircons in the samples of the study area can intuitively judge the age distribution of detrital zircons. After calculating the zircon age contribution rate of the content presented in the figure, combined with the geological data of the study area, the right figure (statistical analysis and visualization of detrital zircon U-Pb age data) is obtained, which can clearly and preliminarily judge the source of the material. Among them, the zircon age characteristics of Balougou, Haizemiao, Shuang 85 and Zhao 54 are similar to the zircon characteristics of the northern Central Asian orogenic belt; the zircon age characteristics of Shantou Village, Yanshui River, Xilangkou and Shangyukou are highly similar to the zircon age distribution of the northern Qinling Mountains.

[0025] Figure 3 This is a multidimensional calibration (MDS) geomorphology map, which can intuitively clarify the relationship between samples and further determine the source information of the samples. It can be clearly seen that the zircon samples are divided into two areas, which shows that their provenance backgrounds are completely different. Among them, Haizemiao, Balougou, Zhao 54 and Shuang 85 are aggregated in the left area. Combined with the probability density map, it is speculated that the zircon formed in the northern Central Asian orogenic belt has a good affinity, indicating that it is mainly affected by the northern source. Shangyukou, Xilukou, Shantou Village and Lingshui River are aggregated in the right area. Combined with the probability density map, it is speculated that the zircon has a good affinity with the northern Qinling Mountains, indicating that it is mainly affected by the southern source.

[0026] Figure 4The cumulative age probability curve can visually express multiple age probability distributions. By superimposing it with the tectonic background, the left figure is obtained, which can intuitively determine the tectonic background of the sample. Combined with the MDS type map, this figure clearly shows that most samples in the north are in the collision compression background, and most samples in the south are in the collision compression and tension extension background.

[0027] The above embodiments are only used to illustrate the present invention, wherein the various implementation steps of the method can be changed, and any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data, characterized in that Use the following specific steps: ⑴ Collect and integrate detrital zircon U-Pb age data from different studies (including published and unpublished data), perform data cleaning and preliminary screening analysis, select appropriate Pb / U and Pb / Pb age ratios to calculate the concordance, and further screen the data with suitable concordance according to zircon age to obtain appropriate detrital zircon U-Pb age data; (2) Using software such as IsoplotR to perform various forms of statistical analysis and visualization on the detrital zircon U-Pb age data, a two-dimensional relative probability density map and histogram of detrital zircon age were obtained, with the detrital zircon age value as the horizontal axis and the detrital zircon sample frequency as the vertical axis, so as to intuitively display the age distribution characteristics in the samples; ⑶ Detailed analysis of the contribution of each zircon age to the sample age interpretation, combined with the geological data of the study area, to quantitatively evaluate the importance of different zircon ages in provenance analysis; (4) Use multidimensional calibration method to quantitatively compare the similarities between samples. Based on the Dmax value of KS test or the Vmax value of Kuiper test, the relative differences between samples are displayed in multidimensional space in the form of points to improve the visualization effect. ⑸ By plotting the difference distribution between zircon crystallization age and deposition age in sediments, the differences in tectonic background of different source-sink systems in sedimentary basins are analyzed, and the cumulative probability curve of zircon age is plotted in combination with the cumulative age distribution CAD function to further explain the dynamic mechanism of the "source-sink system" of tectonic units and their surroundings.

2. A quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data according to claim 1, characterized in that: When visualizing zircon age data, using software such as IsoplotR to draw zircon age-frequency curves can intuitively and clearly obtain the distribution of detrital zircon age values ​​in the sample, clarify the zircon age characteristics of the sample, and lay the foundation for the preliminary determination of provenance information.

3. The quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data according to claim 1, characterized in that: In the quantitative analysis of multidimensional calibration (MDS), IsoplotR software is used to closely combine independent sample data based on the Dmax value of the KS test or the Vmax value of the Kuiper test. The similarity relationship between different samples can be clearly obtained, and the similarities and differences between samples can be quantitatively compared.

4. The quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data according to claim 1, characterized in that: When combining multiple cumulative age curves with tectonic background analysis, the empirical cumulative distribution function (CAD) is used to draw the zircon age value-zircon age probability curve, and combined with the sedimentary period tectonic background divided by the difference between the detrital zircon crystallization age and the stratigraphic sedimentary age, the sample information can be obtained intuitively.

5. The quantitative sedimentary basin provenance analysis method based on detrital zircon U-Pb age data according to claim 1, characterized in that: By using software such as IsoplotR, we can obtain the relative probability density map of detrital zircon, the multidimensional calibration method (MDS) type map, and the cumulative age probability curve map, and intuitively and clearly obtain the basic information of detrital zircon, such as the distribution of detrital zircon age values, the relationship between samples, the accumulation of age values, etc., to more accurately compare the differences between different samples and obtain the provenance information of the samples step by step.

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