Method for inverting density abnormity of rock circle mantle in Kraton neighborhood mountain-building zone

Abstract

The invention discloses a method for inverting density anomaly of a rock circle mantle in a Kratong neighborhood mountain-building zone. Gravity anomaly caused by the earth crust and the mourhos face is removed through the empirical relation between the earth crust speed and density and a gravity forward modeling method. The gravity anomaly forward modeling test of the Kratong neighborhood mountain-building zone lithosphere mantle plate-shaped body is jointly constrained through residual gravity anomaly of the lithosphere mantle and accumulated mass anomaly of the residual lithosphere mantle, and a series of model sets meeting conditions are obtained. And finally, the optimal depth, thickness and residual density of the plate-shaped body model are optimized through the interface constraint obtained by the receiving function. According to the method, known geophysical information is used to the greatest extent, a stable estimation strategy is adopted, reliable rock circle mantle density anomaly information of the Kraton neighborhood mountain-building zone is obtained, the research level of Kraton neighborhood rock circle mantle density anomaly is improved, and the method is suitable for popularization and application. The method has an important promotion effect on mainland lithosphere evolution research and mineral resource exploration.

Description

Technical Field

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

[0002] The density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton is an important parameter controlling the strength and rheological mechanism of the lithospheric mantle in the orogenic belt. Due to the significantly different lithospheric structures and gravity anomalies in the craton and its adjacent orogenic belts, this difference provides the condition for jointly inverting the density anomaly of the lithospheric mantle in the orogenic belt by using gravity and shear-wave velocity structures. Usually, the three-dimensional density inversion of the lithosphere has strong non-uniqueness, resulting in difficulties in evaluating the density anomaly of the lithospheric mantle in the orogenic belt. In addition, due to the complex influence mechanism of factors such as material composition, temperature, and fluid on the velocity structure of the lithospheric mantle, the condition for converting the velocity of the lithospheric mantle into density is not available. Summary of the Invention

[0003] The present invention provides a method for inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton, which is used to solve the problem of difficult evaluation of the density anomaly of the lithospheric mantle in the orogenic belt in the prior art.

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

[0005] Based on the joint inversion of the dense array receiver function and surface wave dispersion, obtain the crustal shear-wave velocity structure and Moho data of the craton and its adjacent orogenic belt, and convert the shear-wave velocity into the P-wave velocity;

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

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

[0008] Combined with the crustal density and the average density of the lithospheric mantle, calculate the forward gravity anomaly of the lithospheric density structure through the gravity anomaly forward formula;

[0009] Perform a complete Bouguer correction on the forward gravity anomaly to obtain the forward Bouguer gravity anomaly of the lithosphere;

[0010] Based on the forward Bouguer gravity anomaly of the lithosphere, calculate the residual gravity anomaly of the lithospheric mantle;

[0011] According to the crustal density and the average density of the lithospheric mantle, calculate the cumulative mass anomaly of the lithospheric mantle;

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

[0013] Based on the mean value of the relative cumulative mass anomaly, a lithospheric mantle slab model is constructed, and a set of models matching the mean value of the relative residual gravity anomaly is selected through gravity simulation tests;

[0014] The set of models is compared with the depths of the Moho discontinuity and the lithosphere-asthenosphere boundary obtained from receiver functions, and the top depth, thickness, and density anomaly value of the lithospheric mantle density anomaly slab in the final craton-adjacent orogenic belt are optimized.

[0015] Optionally, the shear wave velocity is converted to the compressional wave velocity by the following formula:

[0016]

[0017] where V p and V s are the compressional wave velocity and shear wave velocity of the crust respectively.

[0018] Optionally, the crustal density includes: sediment layer density and crystalline basement density, which are obtained by the following formulas respectively:

[0019] Sediment layer density:

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

[0021] where σ s and σ b are the sediment layer density and crystalline basement density respectively.

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

[0023]

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

[0025] Optionally, the complete Bouguer correction includes: topographic correction and intermediate layer correction, and the formula for the intermediate layer correction is:

[0026] Δg c = 0.0419·σ c ·h

[0027] where σ c and h are the density and thickness of the middle layer respectively, and h is the altitude.

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

[0029]

[0030] where is the mean value of the relative cumulative mass anomaly, and T MP is the thickness of the plate-like body.

[0031] Optionally, preferably, the top depth, thickness, and density anomaly value of the lithospheric mantle density anomaly plate of the final craton adjacent orogenic belt include: minimizing the following parameter

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

[0033] where D MP represents the top depth of the plate-like body model, D Moho represents the Moho depth obtained from the seismic receiver function, and 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 delimited by connecting the maximum value points of the horizontal derivative of the gravity anomaly.

[0035] A system for inverting the lithospheric mantle density anomaly of the craton adjacent orogenic belt in the present invention, the system includes:

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

[0037] The conversion unit is used to convert the P-wave velocity into the crustal density;

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

[0039] A second calculation unit, configured to calculate the forward gravity anomaly of the lithospheric density structure by combining the crustal density and the average density of the lithospheric mantle through a forward gravity anomaly formula;

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

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

[0042] A fourth calculation unit, configured to calculate the cumulative mass anomaly of the lithospheric mantle according to the crustal density and the average density of the lithospheric mantle;

[0043] A fifth calculation unit, configured to delimit the boundary between the craton and the adjacent orogenic belt through the horizontal gradient of the gravity anomaly, and calculate the average value of the relative residual gravity anomaly and the average value of the relative cumulative mass anomaly between the two;

[0044] A second acquisition unit, configured to construct a plate-like body model of the lithospheric mantle based on the average value of the relative cumulative mass anomaly, and screen a model set that matches the average value of the relative residual gravity anomaly through a gravity simulation test;

[0045] A third acquisition unit, configured to compare the model set with the depths of the Moho discontinuity and the lithosphere-asthenosphere boundary obtained from the receiver function, and optimize the top depth, thickness, and density anomaly value of the plate-like body of the lithospheric mantle density anomaly in the final craton-adjacent orogenic belt.

[0046] A computer-readable storage medium in the present invention, where 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 described in any one of the above.

[0047] The method of the present invention uses known geophysical information, adopts a stable estimation strategy, and obtains reliable lithospheric mantle density anomaly information of the craton-adjacent orogenic belt. This research improves our research level on the lithospheric mantle density anomaly in the craton neighborhood, and will play an important promoting role in the research on the evolution of the continental lithosphere and the exploration of mineral resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a flowchart of a method for inverting the lithospheric mantle density anomaly of the craton-adjacent orogenic belt in an embodiment of the present invention;

[0049] Figure 2 is a structural diagram of a system for inverting the lithospheric mantle density anomaly of the craton-adjacent orogenic belt in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of convenience in description, only the parts related to the present invention rather than all the structures are shown in the accompanying drawings.

[0051] It should be understood that in various embodiments herein, the magnitudes of the serial numbers of the above processes do not imply the order of execution, and the order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments herein.

[0052] An 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, as Figure 1 shown, including the following steps:

[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 data of the craton and its adjacent orogenic belt, and convert the shear wave velocity into the longitudinal wave velocity; specifically, use the well-defined empirical relationship between the longitudinal wave velocity and the shear wave velocity of crustal rocks for conversion.

[0054] Step 200: Convert the longitudinal wave velocity into the crustal density. Since the lithology and degree of consolidation of the crustal sedimentary layer and crystalline basement are different, they have different density characteristics. Taking the bottom surface of the sedimentary layer as the boundary, different empirical formulas of crustal density - longitudinal wave velocity are used to convert the longitudinal wave velocity into the crustal density.

[0055] Step 300: Calculate the average density of the lithospheric mantle based on the 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 densities of mantle peridotite xenoliths and inclusion samples in the study area, the average value of these mantle rock density values can be calculated.

[0056] Step 400: Combine the crustal density and the average density of the lithospheric mantle obtained in Step 200 and Step 300, and calculate the forward gravity anomaly of the lithospheric density structure through the forward gravity anomaly formula.

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

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

[0059]

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

[0061] Step 700: Calculate the cumulative mass anomaly of the lithospheric mantle according to the crustal density and the average density of the lithospheric mantle. Calculate the cumulative mass anomaly of the lithospheric mantle on the unit horizontal projection area at any position from the surface to a certain fixed depth below the geoid according to the crustal density and the average density of the lithospheric mantle determined in Step 200 and Step 300. The specific formula is:

[0062]

[0063] where topo represents the elevation of the terrain, Z b represents a certain depth below the geoid, generally taken as 100 km, and σ is the crustal density and the average density of the lithospheric mantle determined in Step 200 and Step 300.

[0064] Step 800: Define the boundary between the craton and the adjacent orogenic belt through the horizontal gradient of gravity anomaly, and calculate the mean relative residual gravity anomaly and the mean relative cumulative mass anomaly between the two. Specifically, since the craton and the adjacent orogenic belt have significantly different crustal and lithospheric mantle structures, this difference in structure is reflected in the gravity anomaly and mass anomaly. Define the boundary between the craton and the adjacent orogenic belt through the maximum point of the horizontal derivative of the gravity anomaly. Then, based on the residual gravity anomaly of the lithospheric mantle obtained in Step 600, subtract the mean residual gravity anomaly of the lithospheric mantle of the craton from the mean residual gravity anomaly of the lithospheric mantle of the adjacent orogenic belt of the craton to obtain the mean relative residual gravity anomaly of the lithospheric mantle between the craton and its adjacent orogenic belt; similarly, based on the cumulative mass anomaly of the lithospheric mantle obtained in Step 700, subtract the mean cumulative mass anomaly of the lithospheric mantle of the craton from the mean cumulative mass anomaly of the lithospheric mantle of the adjacent orogenic belt of the craton to obtain the mean relative cumulative mass anomaly of the lithospheric mantle between the craton and its adjacent orogenic belt.

[0065] Step 900: Based on the mean relative cumulative mass anomaly, construct a lithospheric mantle slab model, and screen a set of models that match the mean relative residual gravity anomaly through gravity simulation tests. Specifically, based on the mean relative cumulative mass anomaly of the lithospheric mantle obtained in Step 800, set lithospheric mantle slab models with different top depths, different thicknesses, and different residual densities. The top depth of the slab model starts from the depth value of the Moho discontinuity, with an interval of 10 km, and the thickness of the slab model starts from the crustal thickness value, also with an interval of 10 km. Then calculate the residual density of the slab under any slab thickness condition. Subsequently, use the forward gravity anomaly formula of the thick slab model to perform a series of gravity anomaly simulation calculations on these slabs, and calculate the mean value of the gravity anomaly of each slab. Screen out a set of models that match the mean relative residual gravity anomaly of the lithospheric mantle obtained in Step 800 from the simulation results.

[0066] Step 1000: Compare the set of models with the depths of the Moho discontinuity and the lithosphere-asthenosphere boundary obtained from the receiver function, and optimize the top depth, thickness, and density anomaly value of the lithospheric mantle density anomaly slab of the final craton adjacent orogenic belt.

[0067] The method described in the embodiments of the present invention uses known geophysical information, adopts a stable estimation strategy, and obtains reliable lithospheric mantle density anomaly information of the craton adjacent orogenic belt. This research improves our research level on the lithospheric mantle density anomaly in the craton neighborhood, and will play an important role in promoting the research on continental lithosphere evolution and mineral resource exploration.

[0068] In a preferred embodiment, the conversion formula for the P-wave velocity in Step 100 is:

[0069]

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

[0071] In a preferred embodiment, the crustal density includes: the sediment layer density and the crystalline basement density, which are obtained by the following formulas respectively:

[0072] Sediment layer density:

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

[0074] Among them, σ s and σ b are the sediment layer density and the crystalline basement density respectively.

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

[0076]

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

[0078] In a preferred embodiment, the complete Bouguer correction in step 500 includes topographic 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 intermediate layer density and thickness respectively, h is the altitude. The topographic correction uses the forward gravity anomaly formula in step 400.

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

[0082]

[0083] Among them, is the relative cumulative mass anomaly mean value, T MP is the thickness of the plate-like body.

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

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

[0086] where D MP represents the top depth of the plate-like body model, D Moho represents the Moho depth obtained from the seismic receiver function, and 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 delimited by connecting the maximum value points of the horizontal derivative of the gravity anomaly.

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

[0089]

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

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

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

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

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

[0095] A second calculation unit 204, configured to calculate the forward gravity anomaly of the lithospheric density structure by combining the crustal density and the average density of the lithospheric mantle through the forward gravity anomaly formula;

[0096] A calibration unit 205 for performing 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 for calculating a residual gravity anomaly of the lithospheric mantle based on the forward Bouguer gravity anomaly of the lithosphere;

[0098] A fourth calculation unit 207 for calculating an accumulated mass anomaly of the lithospheric mantle according to the crustal density and the average density of the lithospheric mantle;

[0099] A fifth calculation unit 208 for delineating the boundary between the craton and the adjacent orogenic belt by using the horizontal gradient of the gravity anomaly, and calculating the average value of the relative residual gravity anomaly and the average value of the relative accumulated mass anomaly between the two;

[0100] A second acquisition unit 209 for constructing a plate-like body model of the lithospheric mantle based on the average value of the relative accumulated mass anomaly, and screening a set of models that match the average value of the relative residual gravity anomaly through gravity simulation tests;

[0101] A third acquisition unit 210 for comparing the set of models with the depths of the Moho discontinuity and the lithosphere-asthenosphere boundary obtained from the receiver function, and optimizing the top depth, thickness, and density anomaly value of the plate-like body of the lithospheric mantle density anomaly in the craton-adjacent orogenic belt.

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

[0103] In the embodiment of the present invention, through the clear empirical relationship between the crustal velocity and density, the gravity anomalies caused by the crust and the Moho discontinuity are removed by the gravity forward method. Then, the gravity forward test of the plate-like body of the lithospheric mantle in the craton-adjacent orogenic belt is jointly constrained by the residual gravity anomaly of the lithospheric mantle and the residual accumulated mass anomaly of the lithospheric mantle, and a series of qualified model sets are obtained. Finally, through the interface constraint obtained from the receiver function, the depth, thickness, and residual density of the optimal plate-like body model are optimized. This method makes the most use of the known geophysical information, adopts a stable estimation strategy, and obtains reliable information on the lithospheric mantle density anomaly in the craton-adjacent orogenic belt. This research improves our research level on the lithospheric mantle density anomaly in the craton-adjacent area, and will play an important promoting role in the research on the evolution of the continental lithosphere and the exploration of mineral resources.

[0104] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

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

[0106] These computer program instructions can 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 generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0108] The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that, according to the above teachings, many changes and variations are possible. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton, characterized in that Including the following steps: Based on the joint inversion of dense array receiver functions and surface wave dispersion, obtain the crustal shear wave velocity structure and Moho data of the craton and adjacent orogenic belts, and convert the shear wave velocity to the P-wave velocity; Convert the P-wave velocity to the crustal density; Based on the density statistics of mantle peridotite xenoliths and inclusions in the study area, calculate the average density of the lithospheric mantle; Combining the crustal density and the average density of the lithospheric mantle, calculate the forward gravity anomaly of the lithospheric density structure through the forward gravity anomaly formula; Perform a complete Bouguer correction on the forward gravity anomaly to obtain the forward Bouguer gravity anomaly of the lithosphere; Calculate the residual gravity anomaly of the lithospheric mantle based on the forward Bouguer gravity anomaly of the lithosphere; Calculate the cumulative mass anomaly of the lithospheric mantle according to the crustal density and the average density of the lithospheric mantle; Delimit the boundary between the craton and the adjacent orogenic belt through the horizontal gradient of the gravity anomaly, and calculate the average value of the relative residual gravity anomaly and the average value of the relative cumulative mass anomaly between the two; Based on the average value of the relative cumulative mass anomaly, construct a plate model of the lithospheric mantle, and screen a set of models that match the average value of the relative residual gravity anomaly through gravity simulation tests; Compare the set of models with the depths of the Moho and the lithosphere-asthenosphere boundary obtained from the receiver function, and optimize the top depth, thickness, and density anomaly value of the plate of the lithospheric mantle density anomaly in the final craton adjacent orogenic belt.

2. The method according to claim 1, characterized in that, Convert the shear wave velocity to the P-wave velocity through the following formula: Among them, V p and V s are the longitudinal wave velocity and the shear wave velocity of the earth's crust, respectively.

3. The method according to claim 2, characterized in that, The crustal density includes: sediment layer density and crystalline basement density, which are obtained by the following formulas respectively: Deposit layer density: Crystalline substrate density: σ b = 2.437 + 0.076V p where σ s and σ b are the density of the deposition layer and the density of the crystalline substrate, respectively.

4. The method according to claim 1, wherein The forward gravity anomaly formula is: where \(G = 6.67\times10\) -11 m 3 kg -1 s -2 , is the universal gravitational constant, \(\sigma\) is the density of the lithosphere, \(x\), \(y\), \(z\) are the coordinates of the gravity anomaly observation point, \(x\) i , \(y\) j , \(z\) k are the coordinates of the cube position, 5. The method according to claim 4, wherein The complete Bouguer correction includes: topographic correction and intermediate layer correction, and the intermediate layer correction formula is: Δg c = 0.0419·σ c ·h where σ c and h are the density and thickness of the intermediate layer, respectively, and h is the altitude.

6. The method according to claim 1, wherein The remaining density Δρ of the plate-like body model MP is determined by the following relationship: Among them, is the relative cumulative mass anomaly mean value, and T MP is the thickness of the plate-like body.

7. The method according to claim 6, characterized in that, Optimizing the top depth, thickness, and density anomaly value of the plate of the lithospheric mantle density anomaly 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 represents the top depth of the plate-like body model, D Moho represents 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, wherein Delimit the boundary between the craton and the adjacent orogenic belt through the connection line of the maximum points of the horizontal derivative of the gravity anomaly.

9. A system for jointly inverting the density anomaly of the lithospheric mantle in the orogenic belt adjacent to the craton by using gravity and shear wave velocity structures, characterized in that, The system includes: The first acquisition unit is used to obtain the crustal shear wave velocity structure and Moho data of the craton and adjacent orogenic belts based on the joint inversion of dense array receiver functions and surface wave dispersion, and convert the shear wave velocity to the P-wave velocity; The conversion unit is used to convert the P-wave velocity to the crustal density; The first calculation unit 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; The second calculation unit is used to calculate the forward gravity anomaly of the lithospheric density structure through the forward gravity anomaly formula by combining the crustal density and the average density of the lithospheric mantle; The calibration unit is used to perform a complete Bouguer correction on the forward gravity anomaly to obtain the forward Bouguer gravity anomaly of the lithosphere; The third calculation unit is used to calculate the residual gravity anomaly of the lithospheric mantle based on the forward Bouguer gravity anomaly of the lithosphere; The fourth calculation unit is used to calculate the cumulative mass anomaly of the lithospheric mantle according to the crustal density and the average density of the lithospheric mantle; The fifth calculation unit is used to delimit the boundary between the craton and the adjacent orogenic belt through the horizontal gradient of the gravity anomaly, and calculate the average value of the relative residual gravity anomaly and the average value of the relative cumulative mass anomaly between the two; A second acquisition unit, configured to construct a lithospheric mantle slab model based on the relative cumulative mass anomaly mean value, and screen a model set matching the relative residual gravity anomaly mean value through gravity simulation tests; A third acquisition unit, configured to compare the model set with the depths of the Moho discontinuity and the lithosphere-asthenosphere boundary obtained from receiver functions, and optimize the top depth, thickness, and density anomaly value of the lithospheric mantle density anomaly slab 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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