A method for inverting lithospheric mantle density anomalies in orogenic belts adjacent to cratons

Abstract

The present invention discloses a method for inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton. The gravity anomaly caused by the stripping of the crust and the Moho surface is removed by the empirical relationship between crustal velocity and density and the gravity forward modeling method. The gravity anomaly forward test of the lithospheric mantle plate in the orogenic belt adjacent to the craton is jointly constrained by the residual gravity anomaly of the lithospheric mantle and the accumulated mass anomaly of the residual lithospheric mantle, and a series of qualified model sets are obtained. Finally, the depth, thickness and residual density of the optimal plate model are selected by the interface constraint obtained by the receiver function. The method of the present invention makes maximum use of known geophysical information and adopts a stable estimation strategy to obtain reliable lithospheric mantle density anomaly information of the orogenic belt adjacent to the craton, thereby improving the research level of the lithospheric mantle density anomaly in the orogenic belt adjacent to the craton, and playing an important role in promoting the study of continental lithosphere evolution and mineral resource exploration.

Description

Technical Field

[0001] The present invention relates to the field of geophysics, and in particular to a method for inverting density anomalies of the lithospheric mantle in a craton-adjacent orogenic belt. Background Art

[0002] The density anomaly of the lithospheric mantle in orogenic belts adjacent to cratons is a key parameter controlling the strength and rheological mechanisms of the lithospheric mantle in these orogenic belts. Because the cratons and their adjacent orogenic belts exhibit significantly different lithospheric structures and gravity anomalies, this diversity allows for the combined inversion of gravity and shear-wave velocity structures to estimate the density anomaly in these orogenic belts. Conventional 3D lithospheric density inversions are highly multi-solution complex, making the assessment of density anomalies in these orogenic belts difficult. Furthermore, the complex mechanisms by which the velocity structure of the lithospheric mantle is influenced by factors such as composition, temperature, and fluids make it difficult to convert the velocity of the lithospheric mantle into density. Summary of the Invention

[0003] The present invention provides a method for inverting density anomalies of the lithosphere mantle in a craton-adjacent orogenic belt, which is used to solve the problem of difficulty in evaluating density anomalies of the lithosphere mantle in an orogenic belt in the prior art.

[0004] The method for inverting the lithospheric mantle density anomaly in the craton-adjacent orogenic belt of the present invention comprises the following steps:

[0005] Based on the joint inversion of dense array receiver functions and surface wave dispersion, the crustal shear wave velocity structure and Moho surface data of the craton and adjacent orogenic belt are obtained, and the shear wave velocity is converted into compressional wave velocity.

[0006] converting the P-wave velocity into crustal density;

[0007] Based on the density statistics of mantle peridotite xenoliths and inclusions in the study area, the average density of the lithospheric mantle is calculated;

[0008] Combining the crust density and the average density of the lithospheric mantle, the forward gravity anomaly of the lithospheric density structure is calculated using a gravity anomaly forward modeling formula;

[0009] Performing complete Bouguer correction on the forward gravity anomaly to obtain the lithospheric forward Bouguer gravity anomaly;

[0010] Calculating the lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly;

[0011] Calculating the accumulated mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle;

[0012] The boundary between the craton and the adjacent orogenic belt is delineated by the horizontal gradient of gravity anomaly, and the relative mean of residual gravity anomaly and relative mean of cumulative mass anomaly are calculated.

[0013] Based on the relative cumulative mass anomaly mean, a lithospheric mantle plate model is constructed, and a model set that matches the relative residual gravity anomaly mean is screened through gravity simulation tests;

[0014] The model set is compared with the Moho surface and lithosphere-asthenosphere boundary depth obtained by the receiver function, and the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate in the final craton-adjacent orogenic belt are selected.

[0015] Optionally, convert the shear wave velocity to longitudinal wave velocity using the following formula:

[0016]

[0017] Among them, V p and V s are the longitudinal wave velocity and shear wave velocity of the crust, respectively.

[0018] Optionally, the crust density includes sedimentary layer density and crystalline basement density, which are obtained using the following formulas:

[0019] Sediment density:

[0020] Crystalline base density: σ b =2.437+0.076V p

[0021] Among them, σ s and σ b are the density of the sedimentary layer and the density of the crystalline base, respectively.

[0022] Optionally, the gravity anomaly forward modeling formula is:

[0023]

[0024] Where G = 6.67 × 10 -11 m 3 kg -1 s -2 , is the gravitational constant, σ is the density of the lithosphere, x, y, z are the coordinates of the gravity anomaly observation point, x i ,y j ,z k is the cube position coordinate,

[0025] Optionally, the complete Bouguer correction includes terrain correction and intermediate layer correction. The intermediate layer correction formula is:

[0026] Δg c =0.0419·σ c ·h

[0027] Among them, σ c and h are the density and thickness of the mesosphere, respectively, and h is the altitude.

[0028] Optionally, the residual density Δρ of the plate-like model MP Determined by the following relationship:

[0029]

[0030] in, is the relative cumulative mass anomaly mean, T MP is the thickness of the plate.

[0031] Optionally, optimizing the top depth, thickness and density anomaly values ​​of the lithospheric mantle density anomaly plate in the final craton-adjacent orogenic belt includes minimizing the following parameters:

[0032] P(D MP ,T MP )=|D MP -D Moho |+|T MP -(D LAB -D Moho )|→min

[0033] Among them, D MP Indicates the top depth of the plate-shaped body model, D Moho Denotes the Moho depth obtained from the seismic receiver function, D LAB Represents the depth of the lithosphere-asthenosphere boundary obtained from the seismic receiver function.

[0034] Optionally, the boundary between the craton and the adjacent orogenic belt is delineated by connecting the maximum points of the horizontal derivative of the gravity anomaly.

[0035] A system for inverting lithospheric mantle density anomalies in a craton-adjacent orogenic belt in the present invention comprises:

[0036] The first acquisition unit is used to obtain the crustal shear wave velocity structure and Moho surface data of the craton and adjacent orogenic belt based on the joint inversion of dense array receiver functions and surface wave dispersion, and convert the shear wave velocity into compressional wave velocity;

[0037] A conversion unit, configured to convert the P-wave velocity into crust density;

[0038] The first calculation unit is used to calculate the average density of the lithospheric mantle based on the density statistics of mantle peridotite inclusions and inclusions in the study area;

[0039] A second calculation unit is configured to calculate a forward gravity anomaly of the lithospheric density structure by combining the crust density and the average density of the lithospheric mantle using a gravity anomaly forward modeling formula;

[0040] a calibration unit, configured to perform a complete Bouguer correction on the forward-modeled gravity anomaly to obtain a forward-modeled Bouguer gravity anomaly of the lithosphere;

[0041] a third calculation unit, configured to calculate a lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly;

[0042] a fourth calculation unit, configured to calculate a cumulative mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle;

[0043] The fifth calculation unit is used to delineate the boundary between the craton and the adjacent orogenic belt by the horizontal gradient of gravity anomaly, and calculate the relative residual gravity anomaly mean and relative cumulative mass anomaly mean of the two;

[0044] a second acquisition unit, configured to construct a lithospheric mantle plate model based on the relative cumulative mass anomaly mean, and screen a model set that matches the relative residual gravity anomaly mean through gravity simulation testing;

[0045] The third acquisition unit is used to compare the model set with the Moho surface and the lithosphere-asthenosphere boundary depth obtained by the receiver function, and select the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate body in the final craton-adjacent orogenic belt.

[0046] A computer-readable storage medium in the present invention stores one or more programs, and the one or more programs can be executed by one or more processors to implement any of the methods described above.

[0047] The proposed method utilizes known geophysical information and employs a stable estimation strategy to obtain reliable information on lithospheric mantle density anomalies in orogenic belts adjacent to cratons. This research advances our understanding of lithospheric mantle density anomalies in craton-adjacent orogenic belts and will significantly enhance research on continental lithosphere evolution and mineral resource exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart of a method for inverting lithospheric mantle density anomalies in a craton-adjacent orogenic belt according to an embodiment of the present invention;

[0049] Figure 2 This is a system structure diagram for inverting lithospheric mantle density anomalies in a craton-adjacent orogenic belt in an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0051] It should be understood that in the various embodiments of this document, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0052] The embodiment of the present invention provides a method for inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton, such as Figure 1 As shown, the following steps are included:

[0053] Step 100, based on the joint inversion of dense array receiver functions and surface wave dispersion, obtain the crustal shear wave velocity structure and Moho surface data of the craton and the adjacent orogenic belt, and convert the shear wave velocity into the compressional wave velocity; specifically, the conversion is performed using the clear empirical relationship between the compressional wave velocity and the shear wave velocity of crustal rocks.

[0054] Step 200: Convert the P-wave velocity to crustal density. Because the crustal sedimentary layer and the crystalline basement have different lithologies and degrees of consolidation, they have different density characteristics. Using the bottom of the sedimentary layer as the boundary, the P-wave velocity is converted to crustal density using different empirical formulas for crustal density and P-wave velocity.

[0055] Step 300 calculates the average density of the lithospheric mantle based on density statistics of mantle peridotite xenoliths and inclusions in the study area. Specifically, mantle peridotite xenoliths and inclusions provide direct information on the density of lithospheric mantle rocks. Therefore, by collecting and statistically analyzing the density of mantle peridotite xenoliths and inclusions in the study area, the average density of these mantle rocks can be calculated.

[0056] Step 400 , combining the crust density and the average density of the lithospheric mantle obtained in steps 200 and 300 , and calculating the forward gravity anomaly of the lithospheric density structure using the gravity anomaly forward modeling formula.

[0057] Step 500: Perform a complete Bouguer correction on the forward-modeled gravity anomaly to obtain the forward-modeled Bouguer gravity anomaly of the lithosphere.

[0058] Step 600, calculate the lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly. In order to make the average value of the anomaly approach zero, the average value of the lithospheric mantle residual gravity anomaly is subtracted from the lithospheric mantle residual gravity anomaly to obtain the final lithospheric mantle residual gravity anomaly. Specifically, the forward Bouguer gravity anomaly of the lithosphere obtained in step 500 is subtracted from the WGM2012 Bouguer gravity field model of the study area to obtain the lithospheric mantle residual gravity anomaly. In order to make the average value of the anomaly approach zero, the average value of the lithospheric mantle residual gravity anomaly is subtracted from the lithospheric mantle residual gravity anomaly. The calculation formula is as follows:

[0059]

[0060] where Δg m , Δg W and Δg l They are the lithospheric mantle residual gravity anomaly, the WGM2012 Bouguer gravity field, and the lithospheric forward Bouguer gravity anomaly calculated in step 500. is the average value of the residual gravity anomaly of the lithospheric mantle.

[0061] Step 700: Calculate the accumulated mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle. Based on the crust density and the average density of the lithospheric mantle determined in steps 200 and 300, calculate the accumulated mass anomaly of the lithospheric mantle from the surface to a fixed depth below the geoid per unit horizontal projected area at any location. The specific formula is:

[0062]

[0063] Where topo represents the elevation of the terrain, Z b represents a certain depth below the geoid, which can generally be taken as 100 km, and σ is the crust density and the average density of the lithospheric mantle determined in steps 200 and 300.

[0064] Step 800 delineates the boundary between the craton and adjacent orogenic belts using the horizontal gradient of the gravity anomaly. The relative residual gravity anomaly mean and the relative cumulative mass anomaly mean are calculated. Specifically, because the craton and adjacent orogenic belts have significantly different crustal and lithospheric mantle structures, these differences are reflected in the gravity and mass anomalies. The boundary between the craton and adjacent orogenic belts is delineated by the maximum point of the horizontal derivative of the gravity anomaly. Then, based on the lithospheric mantle residual gravity anomaly obtained in step 600, the mean of the lithospheric mantle residual gravity anomaly of the craton is subtracted from the mean of the lithospheric mantle residual gravity anomaly of the craton's neighboring orogenic belts to obtain the mean of the relative lithospheric mantle residual gravity anomaly between the craton and its neighboring orogenic belts; similarly, based on the lithospheric mantle cumulative mass anomaly obtained in step 700, the mean of the lithospheric mantle cumulative mass anomaly of the craton's neighboring orogenic belts is subtracted from the mean of the lithospheric mantle cumulative mass anomaly of the craton's neighboring orogenic belts to obtain the mean of the relative cumulative mass anomaly of the lithospheric mantle between the craton and its neighboring orogenic belts.

[0065] Step 900: Based on the relative cumulative mass anomaly mean, a lithospheric mantle plate model is constructed, and a model set that matches the relative residual gravity anomaly mean is screened through gravity simulation testing. Specifically, based on the relative cumulative mass anomaly mean of the lithospheric mantle obtained in step 800, lithospheric mantle plate models with different top depths, thicknesses, and residual densities are set. The top depths of the plate models are set from the depth value of the Moho surface, with intervals of 10 km. The thicknesses of the plate models are set from the crust thickness value, with intervals of 10 km. The residual density of the plate under any plate thickness conditions is then calculated. Subsequently, a series of gravity anomaly simulations are performed on these plates using the gravity anomaly forward modeling formula for the thick plate model, and the mean gravity anomaly of each plate is calculated. From the simulation results, a model set that matches the relative residual gravity anomaly mean of the lithospheric mantle obtained in step 800 is screened.

[0066] Step 1000: Compare the model set with the Moho surface and the lithosphere-asthenosphere boundary depth obtained by the receiver function to select the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate in the final craton-adjacent orogenic belt.

[0067] The method described in this embodiment utilizes known geophysical information and employs a stable estimation strategy to obtain reliable information on lithospheric mantle density anomalies in orogenic belts adjacent to cratons. This research advances our understanding of lithospheric mantle density anomalies in craton-adjacent orogenic belts and will significantly enhance research on continental lithospheric evolution and mineral resource exploration.

[0068] In a preferred embodiment, the conversion formula of the longitudinal wave velocity in step 100 is:

[0069]

[0070] Among them, V p and V s are the longitudinal wave velocity and shear wave velocity of the crust, respectively.

[0071] In a preferred embodiment, the crust density includes the sedimentary layer density and the crystalline basement density, which are respectively obtained using the following formulas:

[0072] Sediment density:

[0073] Crystalline base density: σ b =2.437+0.076V p

[0074] Among them, σ s and σ b are the density of the sedimentary layer and the density of the crystalline base, respectively.

[0075] In a preferred embodiment, the gravity anomaly forward modeling formula in step 400 is:

[0076]

[0077] Where G = 6.67*10 -11 m 3 kg -1 s -2 , is the gravitational constant, σ is the density of the lithosphere, x, y, z are the coordinates of the gravity anomaly observation point, x i ,y j ,z k is the cube position coordinate,

[0078] In a preferred embodiment, the full Bouguer correction in step 500 includes terrain correction and intermediate layer correction; the intermediate layer correction formula is:

[0079] Δg c =0.0419·σ c ·h

[0080] Among them, σ c and h are the density and thickness of the middle layer respectively, and h is the altitude. The terrain correction adopts the gravity anomaly forward modeling formula in step 400.

[0081] In a preferred embodiment, the residual density Δρ of the plate-like model in step 900 is MP Determined by the following relationship:

[0082]

[0083] in, is the relative cumulative mass anomaly mean, T MP is the thickness of the plate.

[0084] In a preferred embodiment, the principle of optimizing the model in step 1000 is to minimize the following parameters:

[0085] P(D MP ,T MP )=|D MP -D Moho |+|T MP -(D LAB -D Moho )|→min

[0086] Among them, D MP Indicates the top depth of the plate-shaped body model, D Moho Denotes the Moho depth obtained from the seismic receiver function, D LAB Represents the depth of the lithosphere-asthenosphere boundary obtained from the seismic receiver function.

[0087] In a preferred embodiment, in step 800, the boundary between the craton and the adjacent orogenic belt is delineated by connecting the maximum points of the horizontal derivative of the gravity anomaly.

[0088] In a preferred embodiment, the formula for calculating the average value of the mantle rock density is as follows:

[0089]

[0090] Among them, σ m is the average density of mantle peridotite, is the density of the i-th sample, and N is the total number of samples.

[0091] The specific embodiment of the present invention also provides a system for inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton, such as Figure 2 As shown, the system includes:

[0092] The first acquisition unit 201 is used to obtain the crustal shear wave velocity structure and Moho surface data of the craton and the adjacent orogenic belt based on the joint inversion of the dense array receiver function and the surface wave dispersion, and convert the shear wave velocity into the compressional wave velocity;

[0093] A conversion unit 202, configured to convert the P-wave velocity into crust density;

[0094] The first calculation unit 203 is used to calculate the average density of the lithospheric mantle based on the density statistics of mantle peridotite xenoliths and inclusions in the study area;

[0095] The second calculation unit 204 is configured to calculate the forward gravity anomaly of the lithospheric density structure by combining the crust density and the average density of the lithospheric mantle with the gravity anomaly forward modeling formula;

[0096] The calibration unit 205 is used to perform a complete Bouguer correction on the forward gravity anomaly to obtain a forward Bouguer gravity anomaly of the lithosphere;

[0097] A third calculation unit 206 is configured to calculate a lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly;

[0098] A fourth calculation unit 207 is configured to calculate a cumulative mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle;

[0099] The fifth calculation unit 208 is used to delineate the boundary between the craton and the adjacent orogenic belt by the horizontal gradient of the gravity anomaly, and calculate the relative residual gravity anomaly mean and the relative cumulative mass anomaly mean of the two;

[0100] A second acquisition unit 209 is configured to construct a lithospheric mantle plate model based on the relative cumulative mass anomaly mean, and screen a model set that matches the relative residual gravity anomaly mean through gravity simulation testing;

[0101] The third acquisition unit 210 is used to compare the model set with the Moho surface and the lithosphere-asthenosphere boundary depth obtained by the receiver function, and select the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate body in the final craton-adjacent orogenic belt.

[0102] A specific embodiment of the present invention further provides a computer-readable storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement the method described in any of the above specific embodiments.

[0103] The embodiment of the present invention uses a clear empirical relationship between crustal velocity and density and a gravity forward modeling method to remove the gravity anomaly caused by the crust and the Moho surface. Then, the gravity anomaly forward test of the lithospheric mantle plate in the craton adjacent orogenic belt is jointly constrained by the residual gravity anomaly of the lithospheric mantle and the residual lithospheric mantle accumulated mass anomaly, and a series of qualified model sets are obtained. Finally, we select the depth, thickness and residual density of the optimal plate model through the interface constraint obtained by the receiving function. This method makes maximum use of known geophysical information and adopts a stable estimation strategy to obtain reliable lithospheric mantle density anomaly information of the craton adjacent orogenic belt. This study has improved our research level on the density anomaly of the lithospheric mantle in the craton adjacent orogenic belt and will play an important role in promoting the study of continental lithosphere evolution and mineral resource exploration.

[0104] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0105] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0106] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0108] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for inverting the lithospheric mantle density anomaly of a craton-adjacent orogenic belt, characterized by: The following steps are involved: Based on the joint inversion of dense array receiver functions and surface wave dispersion, the crustal shear wave velocity structure and Moho surface data of the craton and adjacent orogenic belt are obtained, and the shear wave velocity is converted into compressional wave velocity. converting the P-wave velocity into crustal density; Based on the density statistics of mantle peridotite xenoliths and inclusions in the study area, the average density of the lithospheric mantle is calculated; Combining the crust density and the average density of the lithospheric mantle, the forward gravity anomaly of the lithospheric density structure is calculated using a gravity anomaly forward modeling formula; Performing complete Bouguer correction on the forward gravity anomaly to obtain the lithospheric forward Bouguer gravity anomaly; Calculating the lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly; Calculating the accumulated mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle; The boundary between the craton and the adjacent orogenic belt is delineated by the horizontal gradient of gravity anomaly, and the relative mean of residual gravity anomaly and relative mean of cumulative mass anomaly are calculated. Based on the relative cumulative mass anomaly mean, a lithospheric mantle plate model is constructed, and a model set that matches the relative residual gravity anomaly mean is screened through gravity simulation tests; The model set is compared with the Moho surface and lithosphere-asthenosphere boundary depth obtained by the receiver function, and the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate in the final craton-adjacent orogenic belt are selected.

2. The method according to claim 1, characterized in that The shear wave velocity is converted to longitudinal wave velocity using the following formula: Among them, V p and V s are the longitudinal wave velocity and shear wave velocity of the crust, respectively.

3. The method according to claim 2, characterized in that The crust density includes sedimentary layer density and crystalline basement density, which are obtained using the following formulas: Sediment density: Crystalline base density: σ b =2.437+0.076V p Among them, σ s and σ b are the density of the sedimentary layer and the density of the crystalline base, respectively.

4. The method according to claim 1, wherein The forward modeling formula for gravity anomaly is: Where G = 6.67 × 10 -11 m 3 kg -1 s -2 , is the gravitational constant, σ is the density of the lithosphere, x, y, z are the coordinates of the gravity anomaly observation point, x i ,y j ,z k is the cube position coordinate, 5. The method according to claim 4, characterized in that The complete Bouguer correction includes terrain correction and intermediate layer correction. The intermediate layer correction formula is: Δg c =0.0419·s c ·h Among them, σ c and h are the density and thickness of the mesosphere, respectively, and h is the altitude.

6. The method according to claim 1, characterized in that The residual density Δρ of the plate model MP Determined by the following relationship: in, is the relative cumulative mass anomaly mean, T MP is the thickness of the plate.

7. The method according to claim 6, characterized in that The optimization of the top depth, thickness and density anomaly values ​​of the lithospheric mantle density anomaly plate in the final craton-adjacent orogenic belt includes minimizing the following parameters: P(D MP ,T MP )=|D MP -D Moho |+|T MP -(D LAB -D Moho )|→min Among them, D MP Indicates the top depth of the plate-shaped body model, D Moho Denotes the Moho depth obtained from the seismic receiver function, D LAB Represents the depth of the lithosphere-asthenosphere boundary obtained from the seismic receiver function.

8. The method according to claim 1, characterized in that The boundary between the craton and the adjacent orogenic belt is delineated by connecting the maximum points of the horizontal derivative of the gravity anomaly.

9. A system for inverting lithospheric mantle density anomalies in orogenic belts adjacent to cratons using combined gravity and shear wave velocity structures, characterized in that: The system comprises: The first acquisition unit is used to obtain the crustal shear wave velocity structure and Moho surface data of the craton and adjacent orogenic belt based on the joint inversion of dense array receiver functions and surface wave dispersion, and convert the shear wave velocity into compressional wave velocity; A conversion unit, configured to convert the P-wave velocity into crust density; The first calculation unit is used to calculate the average density of the lithospheric mantle based on the density statistics of mantle peridotite inclusions and inclusions in the study area; A second calculation unit is configured to calculate a forward gravity anomaly of the lithospheric density structure by combining the crust density and the average density of the lithospheric mantle using a gravity anomaly forward modeling formula; a calibration unit, configured to perform a complete Bouguer correction on the forward-modeled gravity anomaly to obtain a forward-modeled Bouguer gravity anomaly of the lithosphere; a third calculation unit, configured to calculate a lithospheric mantle residual gravity anomaly based on the lithospheric forward Bouguer gravity anomaly; a fourth calculation unit, configured to calculate a cumulative mass anomaly of the lithospheric mantle based on the crust density and the average density of the lithospheric mantle; The fifth calculation unit is used to delineate the boundary between the craton and the adjacent orogenic belt by the horizontal gradient of gravity anomaly, and calculate the relative residual gravity anomaly mean and relative cumulative mass anomaly mean of the two; a second acquisition unit, configured to construct a lithospheric mantle plate model based on the relative cumulative mass anomaly mean, and screen a model set that matches the relative residual gravity anomaly mean through gravity simulation testing; The third acquisition unit is used to compare the model set with the Moho surface and the lithosphere-asthenosphere boundary depth obtained by the receiver function, and select the top depth, thickness and density anomaly value of the lithospheric mantle density anomaly plate body in the final craton-adjacent orogenic belt.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the method according to any one of claims 1 to 8.

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