A large-scale mapping method for denudation depth.

Abstract

To provide a large-scale denudation depth thematic mapping method.SOLUTION: There is provided a large-scale denudation depth thematic mapping method. The denudation depth mapping method includes: creating a rule for arranging points and lines of a research area, a field sampling rule, a field observation and recording rule and a mineral processing rule; applying a field thermochronology research method to measure and analyze target minerals selected at each field work point; inputting analysis data into improved Low Thermo software, and performing thermal evolution history simulation analysis and denudation depth calculation to obtain a denudation depth at each of the field work point; drawing a denudation depth isopleth map of the research area according to the denudation depth at each field work point; and and, using a large-scale standard map width regional geological map of the research area as a base map, superimposing the base map and the denudation depth isopleth map to acquire a denudation depth map of the research area.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of denudation depth mapping, and in particular to a method for large-scale mapping of denudation depth as a subject. [Background technology]

[0002] After a geological body is formed, it is difficult to keep still during the long-term geological history, and it usually moves due to tectonic activity, and the movement methods include horizontal and vertical movements. The horizontal movement of geological bodies is more highly valued in the field of earth structure research, but in regional geological research and mineral deposit research, people pay more attention to the vertical movement of geological bodies. Intrusive rocks, altered rocks, and metal deposits are usually formed several kilometers to tens of kilometers underground, and due to later tectonic activity, geological bodies are uplifted and further exposed due to denudation. Studying the uplift and erosion denudation process of geological bodies has a double significance of clarifying the regional geological evolution history (earth structure) and studying the mineralization law to promote mineral exploration. (1) Regional geological significance. The upward uplift of geological bodies is usually caused by tectonic activity, and studying the uplift and erosion denudation process of geological bodies can back-analyze the nature, scale, and action process of tectonic events, thereby providing qualitative and quantitative constraints on the regional geological evolution process. (2) The significance of studying the formation, preservation and evolution of mineral deposits. Mineral deposit research not only focuses on the origin and formation of mineral deposits, but also takes into account the preservation and evolution of mineral deposits after their formation. Different mineral deposit generative types, production characteristics, tectonic activity, paleoclimate and paleoenvironment, uplift and denudation, etc., all constitute influencing factors of mineral deposit preservation evolution. Overall, mineral deposit evolution is, firstly, the change experienced by the mineral deposit and ore body itself, and secondly, the change in the environment and spatial location of the mineral deposit. The preservation of mineral deposits depends to a large extent on the weathering and denudation history of the overlying rocks, and the formation of large mineral deposits is closely related to the preservation conditions of their tectonic environment. By quantitatively calculating the uplift and denudation of mineral deposits and regional geological bodies found in the mine belt, the preservation and evolution state of mineral deposits in the mine belt can be evaluated comprehensively, and the exploration and exploration of regional mineral resources can be guided.

[0003] From the above, it can be seen that developing regional denudation depth mapping and more finely depicting the changes in denudation depth at different sites in the region is not only of theoretical importance for the study of regional geological evolution, but also of practical value for regional mineral exploration breakthroughs.

[0004] In addition, by developing denudation depth mapping across the country and even the world, such as regional mapping of 1:50,000 / 1:200,000 / 1:250,000, it is possible to comprehensively understand the vertical change process of the Earth's surface from a macro perspective, internally reverse the evolution history of the Earth's deep structure, and externally explore the constraints of topographical changes on the changes of the hydrosphere and atmosphere, providing new means for the study of the co-evolution of the Earth's multi-spheres. Thermochronological geological mapping includes uplift rate maps, regional denudation rate maps, regional denudation depth (denudation volume) maps, etc. Internationally, such mapping scope is very large, usually an island or even an entire country, so it is formed to be a small-scale map, and the actual operation is relatively simple. From the perspective of practicality, it is only for observing the general change trend within a large area, and has no more practical value. In Japan, there have been many achievements in thermochronological research, but very little in the study of thermochronological mapping. Only a few thermochronological maps of scattered mining areas have been published, but they are all small-scale and non-prescriptive maps without rules.

[0005] At present, no one has carried out the mapping work of denudation depth of geological bodies with large scales such as 1:50000 and 1:200000 with standard base maps, either abroad or in China. Therefore, it is very urgent to explore the method of mapping denudation depth of geological bodies with large scales such as 1:50000 / 1:20000 / 1:25000 with standard base maps, establish the technical specifications for deploying mapping of denudation depth of geological bodies with thermochronology method, and lay the foundation for deploying mapping of denudation depth of geological bodies with large scales such as 1:50000 / 1:20000 / 1:25000 with standard base maps in the whole country and even the whole world. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a large-scale mapping method for denudation depth, which can achieve mapping of denudation depth of geological bodies with large-scale standard base maps such as 1:50,000 and 1:200,000. The data in the obtained denudation depth map is more accurate and in line with the actual situation, so as to provide a more realistic and accurate comprehensive evaluation of the preservation and change state of mineral deposits in mining belts, and to guide regional mineral survey and exploration. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides the following solutions.

[0008] 1. A method for large-scale mapping subject to denudation depth, the method comprising: Creating a rule for arranging field work points and work routes in the research area, and creating a rule for sampling the field work points; To establish field observation and recording rules for thermochronological research and to establish mineral processing rules; applying a thermochronological study method to measure and analyze selected target minerals at each of said field work points to obtain basic analytical data; The basic analysis data is inputted into the improved Low Thermo software to perform thermal evolution history simulation analysis and denudation depth calculation, and obtain the denudation depth at each of the field work points; and the improved Low Thermo software increases the K-feldspar Ar-Ar, plagioclase Ar-Ar and amphibole Ar-Ar dating results based on the conventional Low Thermo to become simulation parameters; The method includes drawing contour maps of denudation depth in the study area according to the denudation depth at each of the field work points, and using a geological map of a standard map width area of ​​1:50,000 or 1:200,000 in the study area as a base map, overlaying the base map and the contour maps of denudation depth to obtain a denudation depth map of the study area.

[0009] Optionally, creating point and line placement rules for field work points and work routes in the study area, specifically, Setting the field work points according to the accuracy of thermochronological analysis, the distribution characteristics of lithology, point representativeness and uniformity; and setting the work route in accordance with a distribution of the outdoor work points.

[0010] Optionally, creating a field sampling rule for sampling at the field work point specifically includes: In the case of intrusive rocks, where the exposed area is less than 5 km2 and the rock stock is a rock mass, one thermochronological research sample should be collected according to the surface exposure conditions and the convenience of sampling. In the case of a "flat rock body" in an intrusive rock, the elevation range within the exposed area is less than 400 meters. If the "flat rock body" is a convergent rock body, 1-2 thermochronological research samples are collected, and the sampling positions are the center of the rock body, the highest point of the exposed rock body, the edge of the rock body, or the lowest point of the exposed rock body; if the "flat rock body" is a strip-shaped rock body, 1-3 thermochronological research samples are collected, and the sampling positions are the center and both ends of the rock body; and the convergent rock body refers to a circular, elliptical, rectangular, etc. For the "three-dimensional rock body" in the intrusive rock, a series of thermochronological research samples should be collected at an elevation difference of 300-400 meters, and the sampling density should be increased at both ends of the rock body. The elevation range within the rock body exposure range of the "three-dimensional rock body" is greater than 400 meters; In the case of a fault zone, setting control points along the fault zone at the center and both ends of the fault zone, and collecting thermochronological study samples on both sides of the fault at the control points; In the case of shear zones, establishing three control points along the shear zone, at the center and at both ends of the shear zone, and collecting at least one thermochronological study sample in each shear zone; In the case of altered strata, according to the exposure conditions of the altered strata, according to the sampling rules of the intrusive rocks, collect thermochronological study samples; For sandstones and shallow metamorphic rocks in sedimentary formations, collect lithology control samples or, depending on lithology and exposure, collect thermochronological study samples with reference to sampling rules for intrusive rocks; In the case of continuous thermochronological sections, this involves selecting one or two sections with large differences in elevation above sea level within the map area, collecting thermochronological research samples according to the specified elevation differences, and making them into thermochronological sections.

[0011] Optionally, develop field observation and recording rules to be applied to thermochronological studies, specifically: Dividing the field operation points into geological control points and geological observation points, and setting data description requirements for the geological control points and the geological observation points; and establishing the format and content of the field log book.

[0012] Optionally, the establishment of mineral processing rules includes the following: When crushing the target minerals, it is necessary to use non-polluting equipment and strictly prevent cross-mixing of samples; When selecting single minerals such as zircon, apatite, and titanite, the completeness of the crystal form must be ensured, the sample must be crushed within a short time, and multiple screening processes must be performed. The sample must not be heated to high temperatures and baked. The heating temperature of the sample must not exceed 45°C. More than 1,000 grains of each single mineral must be selected. When sorting silicate minerals, it is strictly forbidden to contaminate with organic matter during sorting, the particle size must be 60-80 mesh, the purity must be more than 99%, the amount of each single mineral sorted must reach more than 3 grams, and the silicate minerals include amphibole, biotite, potassium feldspar, plagioclase and borosilicate.

[0013] Optionally, applying a thermochronological study method to measure and analyze selected target minerals at each of said field work points to obtain basic analytical data may specifically include: The method includes performing zircon and apatite (U-Th) / He dating analysis, apatite division tracking dating analysis, potassium-containing silicate mineral Ar-Ar dating analysis, zircon U-Pb dating analysis, and whole-rock component analysis on the target minerals selected at the field work points to obtain the basic analysis data, and the basic analysis data includes thermochronological analysis measurement data and component analysis data of the target minerals at each of the field work points.

[0014] Optionally, the basic analysis data at each of the field operation points is input into the improved Low Thermo software to perform thermal evolution history simulation analysis and denudation depth calculation, and obtain the denudation depth at each of the field operation points.

[0015] Optionally, a contour map of denudation depth of the study area is drawn according to the denudation depth at each of the field work points, and a geological map of a standard map width of 1:50000 or 1:20000 of the study area is used as a base map, and the base map and the contour map of denudation depth are superimposed to obtain a denudation depth map of the study area, specifically, constructing a TXT document based on point information and the denudation depth at each of the field operation points; selecting "Discrete Data Grid Type" in MAPGIS software to process said TXT document; According to the processed TXT document, drawing the contour map of said denudation depth using the "plane contour drawing" function in MAPGIS software; Using the "image analysis" function in the "image processing" of MAPGIS, vectorize the geological map of the standard map width area of ​​1:50000 or 1:200000, and use the vectorized geological map as the base map. and applying said denudation depth contour map to corresponding areas of said base map to obtain said denudation depth map. Effect of the Invention

[0016] According to certain embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention provides a large-scale mapping method for the subject of denudation depth, and formulates the field work points and work line point and line arrangement rules, field sampling rules, field observation and recording rules and mineral dressing rules in the research area, and applies the thermochronological research method to measure and analyze the target minerals selected at each field work point, obtain basic analytical data, and convert the basic analytical data into the improved Low The data is input into Thermo software to perform thermal evolution history simulation analysis and denudation depth calculation, and the denudation depth at each field work point is obtained. According to the denudation depth at each field work point, the denudation depth contour map of the study area is drawn. The large-scale standard map of the study area is used as the base map, and the base map and the denudation depth contour map are superimposed to obtain the denudation depth map of the study area. Thus, the mapping of the denudation depth of the geological body with large-scale standard base maps such as 1:50,000 and 1:200,000 can be achieved. The data in the obtained denudation depth map is more accurate and in line with the actual situation, which can provide a more realistic and accurate comprehensive evaluation of the preservation and change state of the ore deposits in the mine belt, and can guide the mineral exploration and exploration in the area. [Brief description of the drawings]

[0017] [Figure 1] 1 is a flowchart of a large-scale mapping method for denudation depth provided by an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of a thermal evolution history forward modeling window provided by an embodiment of the present invention. [Diagram 3] FIG. 2 is a schematic diagram of a thermochronology method selection window provided by an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram of a chronology data input window for a thermal evolution history simulation provided by an embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic diagram of a U-Th / He parameter setting window provided by an embodiment of the present invention. [Figure 6]FIG. 2 is a schematic diagram of a division tracking parameter setting window provided by an embodiment of the present invention; [Figure 7] FIG. 2 is a schematic diagram of a thermal evolution history inversion window provided by an embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram of a one-dimensional denuded calculation window provided by an embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram of a one-dimensional denudation calculation parameter input window provided by an embodiment of the present invention; [Figure 10] FIG. 2 is a schematic diagram of a two-dimensional denudation and paleotopography simulation window provided by an embodiment of the present invention. [Figure 11] FIG. 2 is a schematic diagram of a two-dimensional denudation calculation parameter input window provided by an embodiment of the present invention; [Figure 12] FIG. 2 is a thermal evolution history curve diagram (path display) provided by an embodiment of the present invention. [Figure 13] FIG. 2 is a thermal evolution history curve diagram (conventional style representation) provided by an embodiment of the present invention. [Figure 14] FIG. 2 is a reverse thermal evolution history curve diagram provided by an embodiment of the present invention; [Figure 15] 1 is a diagram showing a calculation result of erosion depth (erosion amount) provided by an embodiment of the present invention. [Figure 16] FIG. 2 is a schematic diagram of setting drawing parameters for a planar contour map provided by an embodiment of the present invention; [Figure 17] 1 is a geological base map library for establishing MAPGIS standard map widths provided by an embodiment of the present invention; [Figure 18] FIG. 1 is a schematic diagram of introducing a denudation volume contour map provided by an embodiment of the present invention into a MAPGIS version geological base map. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The above drawings are for explaining the embodiments of the present invention or the technical solutions in the prior art more clearly. Obviously, the above drawings are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0019] The technical solutions in the embodiments of the present invention will be described below clearly and completely with reference to the drawings in the embodiments of the present invention, and obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts are all within the protection scope of the present invention.

[0020] There are several methods to study the denudation depth (denudation volume) of geological bodies, among which the thermochronology method is the most effective and can provide more accurate quantitative results. Thermochronology, also known as isotope thermochronology, is a new and comprehensive field that combines traditional isotope chronology with other fields. Thermochronology can provide comprehensive information such as time, temperature, and spatial location, so that the thermal evolution process and spatial location change process experienced by geological bodies during their formation and later stages can be precisely defined. Its basic principle is to use the principle of isotope radioactive decay and the difference in the closure temperature of different isotope systems to perform dating analysis on minerals, and by deciphering the information contained therein such as time and temperature, the thermal evolution process experienced by geological bodies, such as the mountain formation process, the rock body uplift cooling history and uplift denudation denudation history, and the thermal evolution history of sedimentary basins, is studied. Its core concepts are the concepts of closure temperature and cooling age. The important pillars of this research are dating techniques such as (U-Th) / He, FT (fission tracking), Ar-Ar, and U-Pb, as well as computer simulation techniques for thermal evolution history.

[0021] The present invention aims to provide a large-scale mapping method for denudation depth, which can achieve mapping of denudation depth of geological bodies with large scales such as 1:50,000 and 1:200,000 and standard base maps.

[0022] In order to make the above objects, features and advantages of the present invention more apparent and comprehensible, the present invention will be described in more detail below with reference to the drawings and the description of the preferred embodiments of the present invention.

[0023] Working Example As shown in FIG. 1 , the present embodiment provides a large-scale mapping method for denudation depth, which includes:

[0024] S1: Create point and line placement rules for field work points and work routes in the study area. Solution design and work preparation: 1. Select the research area, i.e. the mapping area. 2. After selecting the mapping work area, comprehensively collect previous work results related to the area and the adjacent areas, including but not limited to regional geological survey reports, thematic research reports, mining area geological survey reports, scientific research papers and other literature, etc. Comprehensively analyze and organize the results obtained from previous materials to understand the geological structure location of the mapping area, regional geological structure characteristics, regional geological evolution history, distribution range, type and occurrence of important geological bodies such as intrusive rocks, etc. 3. Prepare the work base map. Prepare the standard map width regional geological map of the corresponding scale (1:50,000, 1:200,000, or 1:250,000) that can cover the entire mapping area, digitize it, and integrate it into the digital geological mapping system. Since the work target is to perform mapping with the theme of denudation depth (denudation volume), the mapping of this theme must be established based on the regional geological survey work of the previous person, and the accuracy of the regional geological map of the corresponding scale (1:50,000, 1:200,000, or 1:250,000) of the previous person is assumed to be acknowledged. These standard map width geological maps have two uses. (1) As a hand-held geological map (working map) during the field work period, all field geological surveys and point arrangements, line arrangements, etc. are based on this map. (2) Finally, use it as the base map when completing the denudation depth map. 4. Prepare topographical map (not necessary). According to the scale of the denudation depth map created according to the plan, prepare a topographical map of the corresponding scale. There are two sources of topographical map: (1) Purchase; (2) Create; Collect and download DEM digital topographical map of the study area, import the data into Global Mapper to create contour lines, output in vector format and convert to Mapgis file, thereby obtain a topographical map with contour lines, and then create a field operation base map. 5. Prepare field tools: traditional tools such as geological hammer, compass, magnifying glass, camera, GPS, palmtop computer, laptop, sample bags (different specifications, for hand specimens, chemical analysis samples, large grain samples), etc.

[0025] Specific rules for outdoor point and line placement: Field work is carried out in the selected mapping research work area, and field work points and field work routes are first set, that is, point arrangement and line arrangement need to be carried out first, and then field work can be carried out according to the arranged points and lines. Before this, there is no ready-made field point arrangement and line arrangement rule for large-scale mapping of denudation depth, so through exploration, practice and innovative research, the field point arrangement and line arrangement rule for mapping of denudation depth is established. The biggest difference between thematic mapping and regional mapping is that the field point arrangement and line arrangement research does not need to follow fixed numerical grid-type rules, but needs to select field survey lines and observation research points according to the purpose of the research in combination with the actual situation of the regional geology. For thermochronological research such as denudation depth measurement, the related "events" have correlation and consistency within a certain region, so there is no need to emphasize the compulsion of survey lines and the density of field observation research points, but the distribution and representativeness of points should be paid special attention to, and there is a point distribution in all different parts of the map (center, square). The main issues to consider in thermochronological research and thematic mapping line arrangement and point arrangement are representativeness, then the uniformity of point distribution, and finally the density of points. The field work points are divided into geological control points and observation (research) points, and the number of points can be as many as possible, but it is significantly reduced from the number of points required by the regional geological survey mapping. According to the analysis accuracy of the current low-temperature thermochronology, within the 1:50,000 map range of one standard, 15-20 valid thermochronology data points can meet the requirements when finally completed, corresponding to more than 40 field observation (research) points, and within the 1:200,000 or 1:250,000 map range of one standard, 25-30 valid thermochronology data points can meet the requirements when finally completed, corresponding to more than 60 points that need field observation (research). There are no fixed requirements for the design and quantity of field geological observation routes, and the basis for route design is the layout points. In short, the principle of field line arrangement and point arrangement for mapping denudation depth is to set the route according to the point distribution, taking into consideration the accuracy of thermochronological analysis, the representativeness and uniformity of the distribution points of lithology.

[0026] S2: Create field sampling rules for sampling at the field work points. The mapping of denudation depth can be completed by analyzing geological samples to obtain the amount of denudation, and relevant samples must be collected in the field for analysis and research such as thermochronology. Compared with regional geological mapping, regional exploration mapping, etc., the mapping of denudation depth is very specific, and the field sampling rules of the previous various mapping methods are not applicable. Through exploration, research and practice, the field sampling rules for large-scale mapping of denudation depth have been established. First, the accuracy of the basic research results of lithology, lithology, strata, structure, etc. in the regional geological maps of 1:50,000, 1:200,000 or 1:250,000 is recognized. Based on this, the field sampling rules corresponding to different geological units are formulated.

[0027] (1) Field sampling rules for intrusive rocks 1. In principle, each rock body has a sample control. 2. For each type of rock involved, a set of compositional research samples should be collected, with 5-10 samples (the specific quantity is determined according to the importance of the rock body), each sample weighing 200-500 grams. If the set of rocks has multiple exposures, compositional research samples should be collected for each of the multiple exposures, with the total number reaching 5-10 samples. 3. For small rock bodies (rocks) with an exposed area of ​​less than 5 km2, taking into consideration the surface exposure conditions and the convenience of sampling, one thermochronological sample (special treatment will be made in the case of steep exposure) will be collected. 4. Sampling rules for "flat rock bodies": For flat exposed rock bodies (those with an elevation range of less than 400 meters within the exposed area), different sampling rules are adopted according to their morphology: (1) For convergent morphology rock bodies (meaning that the rock bodies are circular, elliptical, rectangular, etc.), one or two thermochronological samples are controlled, and the sampling positions are the center of the rock body (or the highest exposed point of the rock body) and the edge of the rock body (or the lowest exposed point of the rock body); (2) For strip-shaped rock bodies, one or three thermochronological samples are controlled, and the sampling positions are the center and both ends of the rock body. 5. Sampling rules for "three-dimensional rock bodies": For three-dimensional exposed rock bodies (the elevation range within the exposed range is greater than 400 meters), the principle is to collect series thermochronological research samples with an elevation difference of 300-400 meters, and the sampling density at both ends of the rock body can be appropriately increased.

[0028] (2) Field sampling rules for fault zones In the case of a significant fault zone in the region (one that penetrates the region or has significant structural limits or differences in rock ages between rocks on both sides), control points are set up along the fault zone at its center and both ends, and thermochronological samples are collected on both sides of the fault at the control points. The collection of such samples can be considered comprehensively together with the collection of intrusive and altered rock samples. (3) Field sampling rules for shear zones Three control points will be established along the shear zone, at its centre and at both ends (or on either side), and at least one thermochronological sample will be collected in each shear zone, with an effort to collect highly deformed rock samples. (4) Field sampling rules for altered strata In the case of altered strata such as old basement rocks and other altered rocks, thermochronological study samples should be collected according to the sampling rules for intrusive rocks according to their exposure conditions. (5) Field sampling rules for sedimentary strata For sandstones and shallow metamorphic rocks in sedimentary formations, only lithological control samples should be collected under normal circumstances. If necessary, thermochronological study samples should be collected according to the lithological and exposure conditions, referring to the sampling rules for intrusive rocks. (6) Field sampling rules for thermochronological sections Within the map area, select one or two sections with large elevation difference, and collect thermochronological research samples according to a certain elevation difference (300 to 400 meters) to make a thermochronological section. Within the section, the sampling density can be appropriately increased at the low and high ends of the section. (7) Suggested sampling volumes for various types of rock samples (Note: For important samples, the sampling volume should be appropriately increased, even doubled) 1. Intrusive rocks: ~5kg, 2. Basic rocks: >20kg, 3. Pt-altered rocks (gneiss, amphibolite, etc.): 5~10kg, 4. Other altered rocks: allowance, 5. Sandstone: 5~10kg.

[0029] S3: Develop field observation and recording rules for thermochronological research. Field observation and recording is one of the basic tasks in denudation depth mapping. Based on the contents of regional geological survey records, and combining the special requirements of denudation depth mapping and thermochronological research, the following field recording rules have been explored, formulated and adopted: Requirements for classification and description of geological points, format and contents of field records: Geological points are divided into general geological control points and observation (research) points. 1. Geological control point: a point on a general normal geological observation route, whose observation content is general and can be explained correspondingly and briefly. It has the function of memory aid and curtain raising of serious drama. Geological control points usually only sample by hand and do not do further sampling. 2. Observation (research) point: an extract that describes outdoor geological phenomena, and mostly an analytical measurement sampling point. The geological boundaries to be discovered, important geological phenomena such as mapping unit boundaries, unconformity situations, and intrusion into contact boundaries, exposure areas such as important upper (lower) indicating structures, typical geological phenomena such as typical wrinkle structures, ductile shear zones, and slip surfaces, important primary structures, secondary structures and their structural indicating elements, and special geological boundaries such as fault zones and thrust structures will all be explained as much as possible. Particularly, the explanation focuses on the relevant conditions of the field sampling points and the conditions of the collected rock samples, such as structure, weathered surface color, fresh surface color, main mineral components and their approximate contents.

[0030] S4: Establish mineral processing rules. After collecting rock samples in the field, they need to be processed indoors, through steps such as sample crushing and single mineral sorting, to select single minerals for analytical measurements such as thermochronology. Due to the special nature of thermochronology analysis, special rule requirements are also established for single mineral sorting based on the normal process. 1. First, sample crushing. When crushing rocks, it is necessary to adopt non-polluting equipment and strictly prevent cross-mixing of samples. 2. Select single minerals such as zircon, apatite, and titanite: Ensure the completeness of the crystal form as much as possible, crush the sample for a short time, and sift multiple times. Do not crush the sample into small pieces in one go to avoid crushing large particles of zircon or apatite. Do not heat and bake at high temperatures! (The sample heating temperature should not exceed 45℃! It is best to dry it naturally). For each single mineral, more than 1000 grains should be selected according to the principle. 3. Sort out silicate minerals such as amphibole, biotite, potassium feldspar, plagioclase, and glass feldspar, and it is strictly forbidden to contaminate with organic matter during sorting, and the grain size needs to be 60-80 mesh, the purity needs to be more than 99%, and each of the single mineral amount sorted needs to reach more than 3 grams on the principle.

[0031] S5: Apply thermochronological research methods to measure and analyze selected target minerals at each of said field work points to obtain basic analytical data. The basic analytical data required by the denudation depth mapping laboratory is mainly thermochronological analytical measurement data, and secondarily, compositional analytical data. In "Step 3", after obtaining analytical measurement targets such as various single minerals, select a high-quality laboratory to carry out the relevant analytical measurement. 1. Zircon and apatite (U-Th) / He dating analysis. He is extracted by laser heating, and U and Th are extracted by chemical decomposition. Single-granule mineral (U-Th) / He dating analysis is performed on the study samples, namely zircon and apatite, with 3-5 granules analyzed for each zircon sample and 5 granules analyzed for each apatite sample. 2. Apatite fission tracking dating analysis. Apatite samples are subjected to fission tracking (FT) dating, and the analysis method is preferably ICP-MS plasma mass spectrometry, more preferably conventional external detector method. For conventional external detector method, 30 granules or more per analysis, and for LA-ICP-MS plasma mass spectrometry, 40 points or more per analysis. 3. Ar-Ar dating analysis of potassium-bearing silicate minerals. Potassium-bearing silicate minerals, such as amphibole, biotite, muscovite, potassium feldspar, and plagioclase, selected from the research samples are subjected to Ar-Ar dating analysis using a stepwise heating technique to obtain age spectra and isoclones. 4. Zircon U-Pb dating analysis. LA-ICPMS laser plasma mass spectrometry technology is used to perform zircon U-Pb dating analysis of the research samples. 200 grains are carefully selected for each sample as targets, and the zircon single mineral is polished to 1 / 3 to 1 / 2, and cathode luminescence photography and translucent and reflected light photography are taken. The clear endless belt part is selected for zircon dating analysis, and each sample has more than 20 valid dating analysis points. The measurement contents include 207Pb / 206Pb, 207Pb / 235U, 206Pb / 238U, 208Pb / 232Th isotope ratio values ​​and age, SiO2, Ti, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Pb, Th, U and other element contents. 5. Analysis of whole rock components. Whole rock samples are crushed to 200 mesh size and subjected to major and trace element analysis, as well as isotope analysis of Sr, Nd, etc., to obtain chemical composition and isotope data for the research samples.

[0032] S6: The basic analysis data is input into the improved Low Thermo software to perform thermal evolution history simulation analysis and denudation depth calculation, and the denudation depth at each of the field work points is obtained. The improved Low Thermo software increases the K-feldspar Ar-Ar, plagioclase Ar-Ar and amphibole Ar-Ar dating results based on the conventional Low Thermo as simulation parameters. The thermal history simulation and denudation volume calculation process are explained using the Low-T Thermo software as an example. Main functions and applications of "Low-T Thermo" thermochronology simulation software: (1) Low-temperature chronology thermal history simulation (including apatite and zircon (U-Th) / He, apatite and zircon fission tracking, mica Ar-Ar, K-feldspar Ar-Ar, plagioclase Ar-Ar, amphibole Ar-Ar, bedrock quartz photoluminescence, vitrinite reflectance, and combinations of the above methods) for thermal history restoration of orogenic belts and basins. (2) Quantitative denudation calculation for each period based on thermal history for research on denudation depth of geological bodies, ore deposit preservation conditions, etc. (3) Paleotopography simulation based on thermal history for research on paleotopography restoration, etc. In the initial version, this software is used for the Ar-Ar thermochronology method of thermal history simulation diagram, and only applies the Ar-Ar dating results of biotite. The Ar isotope closure temperature interval of biotite is 310-345°C, which has a large temperature difference with the U-Pb closure temperature of zircon (800°C), which is likely to cause distortion of the thermal history simulation of the high temperature part. At the same time, the Ar isotope closure temperature interval of biotite and the He closure temperature of zircon (200°C) also have a large temperature difference, which is likely to cause distortion of the thermal history simulation of the medium temperature part. The software has been modified to increase the dating results of K-feldspar Ar-Ar, plagioclase Ar-Ar, and amphibole Ar-Ar, etc. as simulation parameters, which further improves the accuracy of the thermal history simulation of the medium to high temperature part, and more accurate denudation depth values ​​can be obtained. In the improved software, there are nine different thermochronological methods used for thermal history simulation. These nine methods can be selected arbitrarily, including single or multiple selections. Theoretically, there are 255 combination modes, including single method selection.

[0033] (1) Installation Low-T Thermo is compiled by Mathematica and VB.net under Microsoft Windows operating system. Therefore, before use, you need to install Mathematica 10.0 and copy Wolfram.NETLink.dll to the directory where the main program Low.exe is located. You also need Microsoft .NET Framework 2.0 or higher. (2) Program interface and usage overview 1. Thermal history forward modeling window, as shown in Figure 2. After inputting the Time (Ma), the corresponding Temperature (oC) and other parameters, press the "Start Modeling" button to output the age and length distribution results corresponding to the input thermal history curve. 2. Thermochronology method selection window, as shown in Figure 3. In this window, there are 9 different thermochronological methods used for thermal history simulation. The 9 methods can be selected arbitrarily, including single or multiple selections. In theory, there are 255 combination modes including single method selection. The output directory is used to place all the calculated and derived data and graphic files. 3. Input window, as shown in Figure 4. After selecting different thermochronological methods, click "Next" to enter the input window and input the corresponding experimental data and parameters. Each data input box is equivalent to a notepad, and the data can be edited arbitrarily. This is convenient for copying and pasting data from other software, and it can be further edited if necessary. For the specific input format, you can refer to the conventional data format example, and just replace the example data when inputting. Multi-line input can be started by pressing the Enter key. The space between data can be one or more spaces, and can also be made a space by pressing the Tab key. For the U-Th / He method, the stopping distance of alpha particles can be selected from Farley et al., 1996 or Ketcham, et al., 2011 modes. For many granules, "Using multiple ages one by one" can be selected, in which each granule is used to screen the hypothetical paths one by one, and "Using multiple ages together" simulation can be selected, in which each granule is used to screen the hypothetical paths unified, and finally take the average acceptable GOF range. "Using mean age" is used to select the average age of all granules to screen the hypothetical paths, as shown in Figure 5. "Number of grids for R" is used to set the number of finite difference nodes, the default is 20, the maximum setting is 100. The higher the value, the denser the grid and the greater the accuracy, but the slower the calculation. This value has a limited effect on the calculation results of (U-Th) / He simulation age, and can usually be set to 20 to meet most needs. "Show modeled He age distribution" is used to set whether to display the distribution map of He granule age according to the effective uranium concentration. For split tracking method, "Default Lo(c) constant value (μm)" is the default Lo(c) (initial closed tracking length by projection calibration). "Lo(c)=" is used to set the Lo(c) value via Dpar (μm). "Restore Default" restores the default settings, shown in Figure 6. For vitrinite reflectance %Ro, the calibration modes include EASY%Ro (Sweeney and Burnham, 1990), IKU%Ro (Ritter et al., 1996) and basin%Ro (Nielsen et al., 2016). 4. The main window (thermal history inversion window) is shown in Figure 7. "Ts(℃,at sea level)": Surface temperature at sea level (unit: Celsius). "Elevation(m)": The elevation at which the sample is located. The atmospheric vertical temperature gradient defaults to 6°C / km. "Tmax (℃)": Maximum ordinate value. Since the ordinate in the thermal history simulation output diagram is temperature, it is necessary to set the coordinate axis display range. "Duration (Ma)": Maximum abscissa value. Since the abscissa in the thermal history simulation output diagram is time, it is necessary to set the coordinate axis display range. "Paths Tried": The number of thermal history paths searched during the inversion, usually 10,000 (can be self-defined according to actual needs). "Acceptable Fit": The acceptable degree of fit (GOF), which is usually 0.05. You can set it yourself according to your actual needs. "Interval nodes": Interval nodes. When the user gives a constraint box according to background information such as actual geological conditions, it is the number of nodes between every two adjacent constraint boxes, for example, three. "Nodes when no box": The number of nodes for each random path when there is no constraint box (e.g. take 10). "Box(timemin, timemax, Tempmin, Tempmax)": If there is a constraint box, enter the time and temperature range of the constraint box here. Enter the minimum time value in "timemin", the maximum time value in "timemax", the minimum temperature value in "Tempmin", and the maximum temperature value in "Tempmax". Each constraint box occupies one line. If there are multiple lines, press the Enter key to change lines. The "Clear All" button is used to remove all previous parameter entries. The "Save as default" button is used to save all previous parameter inputs and make them the default inputs for the next simulation. "Preview boxes distribution" Preview the constraint boxes. "Start Modeling": Starts the inversion simulation button. "Terminate" End the inversion simulation button. If there is an execution error or you do not have time to wait for the program to run, you can press this key to stop the inversion and end the simulation. "Modeled Result": This box is used to display the thermal history simulation results. Default display: Default style display. When this option is selected, all acceptable paths are displayed. The black line is the average result of all acceptable paths. "Traditional display": Traditional style display. Selecting this option displays only the boundaries of all acceptable paths, similar to the display style of AFTSolve (Ketcham et al., 2000) and HeFTy (Ketcham, 2005). The green range represents the acceptable range (GOF ≥ Acceptable Fit). The pink range represents the high accuracy range (GOF ≥ 0.5). If a high accuracy range exists, the black line is the average result of paths that are within all high accuracy ranges, otherwise the black line is the average result of all acceptable paths. “Modeled He age distribution” is used to display the distribution of He granule ages according to the effective uranium concentration. The radiation damage accumulation and annealing model for apatite adopts RDAAM (Flowers et al., 2009), and the radiation damage accumulation and annealing model for zircon adopts ZrRDAAM (Guenthner et al., 2013). "Modeled AFT length distribution" is used to display the length distribution of the sealed traces of the apatite fission traces. In the text boxes on the right, the age values ​​corresponding to the thermal history simulation results (i.e., black lines) of the different selected thermochronological methods are displayed. "Modeled Report" is used to display the detailed calculation process and report related information. When "The end" or "No Result" appears, it means the simulation is finished. After the thermal history simulation is completed, the graphics are finally output in “.pdf” format and saved in the output directory initially set by the user for subsequent editing by the user. 5. One-dimensional bare calculation window, shown in Figure 8. "Temperature" button, used to select temperature data for the thermal history curve. The "time" button is used to select the time data of the thermal history curve. "Exhumation Cal" button, used to perform the conversion of the thermal history curve from temperature-time curve to denudation thickness-time curve. "Ts(at sea level)" and "Elevation(m)" are the same as previously described. "Temperature Gradient" is the geothermal gradient. "Turning Range" is the inflection point selection range of the high temperature part. "Turning Range" is used to calibrate the starting point when the thermal history extends from the low temperature part to the high temperature part, i.e., the inflection point interval of the low temperature part and the high temperature part. If it is empty, the program will search for the inflection point of the maximum angle within the entire period. If the user inputs an approximate time range, the inflection point positions of the searched low temperature part and high temperature part will be closer to the actual geological situation more easily. "Output interval": The time interval for outputting the calculation results. For example, if you enter 1, it indicates that one denudation thickness data is extracted every 1Ma, as shown in Figure 9. 6. The two-dimensional denudation and paleotopography simulation window is shown in Figure 10. "Samples'Distance(km)" The interval at which samples are input. "Samples'Elevation(km)" The altitude at which the samples are entered. "Corresponding Temperature(°C)" The paleotemperature at which the sample is input. The results of displaying the two-dimensional paleotopography simulation in the “Paleotopography” window and the results of displaying the denudation thickness simulation in the “Exhumation thickness” window are shown in Figure 11. The listed parameters are sea surface temperature, atmospheric vertical geothermal gradient, base temperature, base depth, topographic wavelength, effective elastic thickness, Young's modulus, Poisson's ratio, mantle density, crustal density, thermal diffusion coefficient, gravitational acceleration, time node, initial search height difference value (>0), and initial search wavelength index. Custom settings of parameters can be made by referring to the program default values. All graphics and associated data that appear in the main simulation window are automatically output to a directory. These graphics (Figures 12-15) are saved as PDF format files and can be re-edited in various vector editing software such as Adobe Illustrator, CorelDRAW, etc.

[0034] S7: Draw contour maps of denudation depth in the research area according to the denudation depth at each of the field work points, and use a geological map of the research area with a standard map width of 1:50,000 or 1:200,000 as a base map to overlay the base map and the contour maps of denudation depth to obtain a denudation depth map of the research area. After obtaining the denudation depth (denudation volume) data of multiple geological points, the geological map of the standard map width area of ​​1:50,000 or 1:200,000 was used as the base map to draw maps using MAPGIS software, and contour maps were used to show the changes in denudation depth in the study area. The grid-type calculation method adopted was the "King universal kriging grid type". The specific process is as follows: Data preparation: The point information and denudation volume information of the corresponding sampling points are imported into a TXT file. Discrete data grid type: Apply the "DTM analysis" program in the MAPGIS software "spatial analysis" to perform the grid type work. Preferably, select "discrete data grid type" to process the above TXT document. Then, set the corresponding grid parameters (grid interval, etc.), for example, select the grid type method, and in this simulation, we adopted "Kring universal kriging grid type". Plane contour drawing: First, open the triangulation file and select the "Plane contour drawing" function. Then, set the plane contour drawing parameters, such as contour segment parameters, smoothness degree, etc. Then, draw the plane contour map, as shown in Figure 16. Vectorization Taking the standard map width regional geological map of 1:5000 or 1:20000 as the base map: 1. Use the "image analysis" function in "image processing" in MAPGIS to convert the 1:5W geological base map into the file type loaded by MAPGIS software. 2. Carry out vectorization work on the above file, that is, establish the corresponding point, line, and surface files. 3. Carry out vectorization work on the corresponding geological map of the structural position, regional granite distribution map, etc., and merge it into a 1:5W geological vector file, as shown in Figure 17. Introduction of denudation contour maps: The established planimetric contour maps are introduced into the corresponding geological base map library files for optimization processing (e.g., whether the points are covered or not), as shown in Figure 18. Complete mapping elements: Add graphic scale, compass, map legend, map set and other mapping elements outside the map box, add map description, adjust the map style and color, and make printing modifications to the details of the map to complete the visualization effect of the map. Figure output: Use the mapgif output function to output an image file.

[0035] In this embodiment, no one has carried out the mapping work of regional geological body denudation depth with large scales such as 1:50000 and 1:200000 standard base maps, neither in China nor abroad, and there are no corresponding mapping specifications. This method systematically establishes the mapping specification of regional geological body denudation depth of 1:50000 / 1:200000 through exploration and research, which is original and innovative as a whole, and has many highlights and advantages. 1. Develop the field line arrangement and point arrangement rules for mapping denudation depth (corresponding "Step S1"). In terms of studying point arrangement and line arrangement in the field, break the fixed numerical grid type rules adopted by traditional regional geological mapping, and select field survey lines and observation research points in combination with the actual situation of regional geology according to the purpose of the research. In thermochronological research, the related "events" have interlocking and consistency within a certain area, so there is no need to emphasize the compulsion of the survey line and the density of the field observation research points, but it should be noted that there is a point distribution in all different parts of the map width (center, square). The main issues to be considered in the mapping line arrangement and point arrangement on the subject of denudation depth are representativeness, then the uniformity of point distribution, and finally the density of points. The field line arrangement and point arrangement principle for mapping denudation depth determined in this way is to comprehensively consider the accuracy of thermochronological analysis, the distribution of lithology, and the uniformity of points to set points, and set lines according to the point distribution. 2. Develop field sampling rules for mapping denudation depth (corresponding to "Step S2"). For intrusive rocks with different occurrences, establish sampling rules such as "stump-like rock body", "planar rock body", "three-dimensional rock body", etc. For important fault zones in the region (penetrating through the region or important structural limits, or there is a difference in the rock age of the rocks on both sides), set control points along the fault zone at its center and both ends, and collect thermochronological research samples on both sides of the fault zone at the control points. For shear zones, set three control points along the shear zone at its center and both ends (or both sides), collect at least one thermochronological research sample in each shear zone, and try to collect highly deformed rock samples, and make sure that the Pt old basement rocks and other altered rocks are metamorphosed. For sedimentary strata, refer to the sampling rules of intrusive rocks to collect thermochronological research samples; for sandstone and shallow metamorphic rocks in sedimentary strata, make lines and points significantly sparse according to the regional mapping specifications of 1:50,000 / 1:200,000 / 1:250,000, and collect thermochronological research samples as necessary, and set up thermochronological continuous cross sections: within the map width, select 1-2 cross sections with large elevation difference, and collect thermochronological research samples according to a certain elevation difference (300 meters to 400 meters); within the cross section, the sampling density can be appropriately increased at the low elevation end and the high elevation end to make a thermochronological cross section; for rocks of different lithologies, reasonable sampling volume suggestions are given. 3. Create field observation and recording rules (corresponding to "Step S3") applicable to thermochronological research, simplify the content of the conventional regional mapping records, and especially increase the content of sample descriptions and field photography records of sample points. 4. Formulate mineral processing rules (corresponding to "Step S4"). After collecting rock samples in the field, the next important task is to select single minerals for use in thermochronological analysis. Due to the particularity of thermochronological analysis, there are also special requirements for the selection of single minerals. Based on the normal process, formulate mineral processing specifications, especially for zircon, apatite, titanite and other minerals: ensure the integrity of the crystal form as much as possible, shorten the time of sample crushing, sieve multiple times, and do not crush finely in one go to crush large particles of zircon or apatite. Prohibit high temperature heating and baking! (Sample heating temperature must not exceed 45°C! Preferably, dry naturally). 5. For the different thermal evolution temperature stages experienced by the rocks, basic data will be obtained by adopting thermochronological research methods corresponding to those temperature ranges (corresponding to "Step S5"): (1) The magmatism stage and the high-temperature cooling stage of the rock mass (high-temperature thermal evolution processes such as magmatism crystallization-disposition-in-situ cooling) will be studied using high-temperature thermochronological methods such as zircon U-Pb isotope dating and amphibole and borosilicate Ar-Ar dating. (2) The rock mass uplift and denudation process will be studied mainly using mid- to low-temperature thermochronological methods such as biotite, muscovite, plagioclase and low activation energy potassium feldspar Ar-Ar dating, zircon and apatite fission tracking dating and (U-Th) / He dating. 6. Low-T Thermo software is used to perform thermal history simulation analysis and erosion volume calculation (corresponding to "Step S6"). When conducting thermal history simulation research, software such as HeFTy, QTQt, etc. are used at home and abroad, but they have many shortcomings, such as single function, narrow scope of use, or inapplicable to multi-method thermochronological data, and cannot directly obtain erosion data, rock formation depth and other information. "Low-T Thermo" thermochronological simulation software is used, its main functions and applications: (1) Multi-method low-temperature chronological thermal history simulation can be performed using U-Th / He containing apatite and zircon, apatite and zircon fission tracking, mica Ar-Ar, amphibole Ar-Ar, bedrock quartz photoluminescence, vitrinite reflectance and the combination method of the above various methods to perform low-temperature chronological thermal history simulation. There are 9 different thermochronological methods used in thermal history simulation, and these 9 methods can be selected arbitrarily, including single or multiple options, and there are theoretically 255 combination modes. Applicable to the thermal history recovery of orogenic belts and basins. (2) The calculation of the quantitative denudation amount for each period based on thermal history is applied to the study of denudation depth of geological bodies, ore deposit preservation conditions, etc. (3) The simulation of paleo-topography based on thermal history is applied to the study of paleo-topography restoration, etc. (4) The thermal evolution history curve can be displayed in the reverse direction, and the denudation depth (denudation amount) calculation results can be directly output and displayed in numbers and graphics. In the initial version, the software is used for the Ar-Ar thermochronology method of the thermal history simulation diagram, and only applies the Ar-Ar dating results of biotite. The biotite Ar isotope closure temperature interval is 310-345°C, which has a large temperature difference with the zircon U-Pb closure temperature (800°C), which is likely to cause distortion of the thermal history simulation in the high temperature part. At the same time, the Ar isotope closure temperature interval of biotite and the zircon He closure temperature (200°C) also have a large temperature difference, which is likely to cause distortion of the thermal history simulation in the medium temperature part. The software can be modified to include more Ar-Ar dating data for potassium feldspar, Ar-Ar plagioclase, and Ar-Ar amphibole as simulation parameters, which can further improve the accuracy of the thermal history simulation in the mid-high temperature region and help obtain more accurate denudation depth values. 7. The final product map has several advantages (corresponding to "Step S7"): (1) After the standard width regional geological map is vectorized, it is drawn as a base map, and the planimetric contour map is introduced into the corresponding geological bottom map, and the two are superimposed to create a denudation depth map. In the map created in this way, each geological element such as the distribution of geological bodies, structure, lithology, etc., is fully corresponding to the regional geological map of the relevant scale, which facilitates the use of the denudation depth map to carry out regional geological research and mineral exploration. The previous person arbitrarily adopted the base map, which is inconvenient to use and has limited application value. (2) The point density of the final completed map is high, and the accuracy of the constructed denudation depth map is higher. (3) The scale of the map is large, and the regional denudation history can be displayed in more detail. The denudation depth map constructed by the previous person is smaller in scale and is only suitable for expressing wide-area macro phenomena, and has no application value for regional research. (4) Isolines are used to show the denudation depth, which helps users quickly understand the degree of denudation and the changes in denudation depth in the study area.

[0036] In this specification, the principle and embodiment of the present invention are described by applying specific examples, and the description of the above examples is only useful for understanding the method of the present invention and its core idea, and at the same time, those skilled in the art may change the form and application scope of the invention according to the idea of ​​the present invention. In summary, the contents of this specification should not be understood as limitations on the present invention.

Claims

1. 1. A method for large-scale mapping of denudation depth, comprising: Creating a rule for arranging field work points and work routes in the research area, and creating a rule for sampling the field work points; To establish field observation and recording rules for thermochronological research and to establish mineral processing rules; applying thermochronological research methods to measure and analyze selected target minerals at each of said field work points to obtain basic analytical data; The basic analysis data is inputted into a data processing unit, and the data processing unit performs thermal evolution history simulation analysis and denudation depth calculation, so as to obtain the denudation depth at each of the field operation points; A method comprising: drawing a contour map of denudation depth of the study area according to the denudation depth at each of the field work points; and using a geological map of a standard map width area of ​​1:50,000 or 1:200,000 of the study area as a base map, overlaying the contour map of denudation depth on the base map to obtain a denudation depth map of the study area.

2. Specifically, the establishment of the placement rules of field work points and work routes in the study area includes: Setting the field work points according to the accuracy of thermochronological analysis, the distribution characteristics of lithology, point representativeness and uniformity; The method according to claim 1, further comprising: setting the work route in accordance with a distribution of the outdoor work points.

3. Specifically, establishing field sampling rules for sampling at the field work points includes: In the case of intrusive rocks, for "rock stocks" with an exposed area of ​​less than 5 km2, one thermochronological study sample shall be collected according to the surface exposure conditions and sampling convenience conditions; In the case of a "flat rock body" in an intrusive rock, the difference between the highest and lowest elevations in the elevation range within the exposed area is less than 400 meters. If the "flat rock body" is a convergent morphology rock body, collect 1-2 thermochronological research samples, and the sampling positions are the center of the rock body, the highest point of the exposed rock body, the edge of the rock body, or the lowest point of the exposed rock body; if the "flat rock body" is a strip-like shaped rock body, collect 1-3 thermochronological research samples, and the sampling positions are the center and both ends of the rock body; In the case of a "three-dimensional rock body" in an intrusive rock, a series of thermochronological study samples are collected at an elevation difference of 300 to 400 meters, and the sampling density is increased at both ends of the rock body, and the difference between the highest elevation and the lowest elevation in the elevation range within the rock body exposure range of the "three-dimensional rock body" is greater than 400 meters; In the case of a fault zone, setting control points along the fault zone at the center and both ends of the fault zone, and collecting thermochronological study samples on both sides of the fault at the control points, respectively; in the case of a shear zone, setting three control points along the shear zone at the center and both ends of the shear zone, and collecting at least one thermochronological study sample in each shear zone; In the case of altered strata, according to the exposure conditions of the altered strata, according to the sampling rules of the intrusive rocks, collect thermochronological study samples; For sandstones and shallow metamorphic rocks in sedimentary formations, collect lithology control samples or, depending on lithology and exposure, collect thermochronological study samples with reference to sampling rules for intrusive rocks; 2. The method of claim 1, comprising:

4. Specifically, the development of field observation and recording rules for thermochronological research includes: Dividing the field operation points into geological control points and geological observation points, and setting data description requirements for the geological control points and the geological observation points; and setting the format and contents of the field logbook.

1. The method according to claim 1.

5. Specifically, establishing mineral dressing rules means: When crushing the target minerals, use non-polluting equipment to prevent cross-mixing of samples; When selecting single minerals such as zircon, apatite, and titanite, it is necessary to ensure the completeness of the crystal form, complete the sample crushing within a short time, and perform multiple screening. It is prohibited to heat and burn the sample at high temperatures, and the heating temperature of the sample must not exceed 45°C. Each single mineral must have more than 1,000 grains. The method according to claim 1, characterized in that, when separating silicate minerals, the silicate minerals are prohibited from being contaminated by organic matter during separation, and the particle size is required to be 60-80 mesh, the purity is required to be 99% or more, and the amount of each single mineral separated reaches 3 grams or more; and the silicate minerals include amphibole, biotite, potassium feldspar, plagioclase and borosilicate.

6. The application of thermochronological research methods to measure and analyze selected target minerals at each of the field work points to obtain basic analytical data includes, specifically: The method according to claim 1, characterized in that the method includes performing zircon, apatite (U-Th) / He dating analysis, apatite fission tracking dating analysis, potassium-containing silicate mineral Ar-Ar dating analysis, zircon U-Pb dating analysis, and whole-rock component analysis on the target minerals selected at the field work points to obtain the basic analysis data, and the basic analysis data includes thermochronological analysis measurement data and component analysis data of the target minerals at each of the field work points.

7. The method according to claim 1, characterized in that the basic analysis data at each of the field work points is input into a data processing unit to perform thermal evolution history simulation analysis and denudation depth calculation, and obtain the denudation depth at each of the field work points.

8. Specifically, the method includes drawing contour maps of denudation depths of the research area according to the denudation depths at each of the field work points, and using a geological map of a standard map width area of ​​1:50,000 or 1:200,000 of the research area as a base map, overlaying the base map and the contour maps of denudation depths to obtain a denudation depth map of the research area. constructing a TXT document based on point information and the denudation depth at each of the field work points; processing said TXT document in a geographic information processing unit; Utilizing a geographic information processing unit to plot said denudation depth contour maps in response to the processed TXT document; Using a geographic information processing unit, vectorization is performed on a geological map of a standard map area of ​​1:50,000 or 1:200,000, and the vectorized geological map is used as the base map; 2. The method of claim 1, further comprising: applying the contour map of denudation depth to a corresponding area of ​​the base map to obtain the denudation depth map.

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