Method and device for determining mixed dyeing proportion of earth crust components in magma

Abstract

The invention relates to a method and a device for determining the mixed dyeing proportion of earth crust components in magma. The method comprises the following steps: dating a sample to be detected to obtain the crystallization age t of the magma; performing Nd and Sr isotope testing on the whole rock to obtain an epsilon Nd (t) value and an ISr value, generating a scatter diagram, and determining the epsilon Nd (t) value and the ISr value of the initial magma and the surrounding rock; performing quantitative simulation calculation on the change of the Sr-Nd isotope of the initial magma under the joint control of separation crystallization and surrounding rock mixed dyeing; and generating a scatter diagram by the epsilon Nd (t) values of the magma and ISr under different evolution processes to obtain an AFC evolution trend line of the Sr-Nd isotope of the magma, comparing the AFC evolution trend line with data points of a sample to be detected, and reading the crustal component mixed dyeing proportion according to a calculation result. According to the method, the magma Sr-Nd isotope is taken as a carrier, two magma evolution effects of mineral separation crystallization and crustal mixed dyeing are quantitatively described based on the AFC model, and quantitative estimation of the crustal mixed dyeing proportion in the AFC process is realized.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of geology, and in particular to a method and device for determining the proportion of crustal component contamination in magma. BACKGROUND

[0002] The formation of magma often needs to go through complex crust-mantle interaction. At present, the method for quantitatively determining the proportion of crustal component contamination in magma is mainly based on a simple two-end member mixing model. However, in fact, the model is only applicable to the mixing process of magma, and the evolution of magma includes not only the two-end member mixing process, but also the process of mantle source magma assimilating and contaminating the surrounding rock based on the AFC mechanism, that is, the mantle source magma is controlled by the two processes of fractional crystallization and crustal wall rock assimilation and fractional crystallization (AFC) in the evolution process.

[0003] Since the existing technology provides a scheme based on the two-end member mixing model, it is difficult to realize the real simulation of the two processes of fractional crystallization and crustal wall rock assimilation, and thus it is also difficult to determine the proportion of crustal component contamination in magma. Therefore, it is urgent to propose a calculation scheme based on the AFC mechanism and capable of simulating the two processes of fractional crystallization and crustal wall rock assimilation of mantle source magma. SUMMARY

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, embodiments of the present disclosure provide a method and device for determining the proportion of crustal component contamination in magma.

[0005] In a first aspect, embodiments of the present disclosure provide a method for determining the proportion of crustal component contamination in magma, comprising:

[0006] S1: dating a to-be-tested sample to obtain a crystallization age t of magma of the to-be-tested sample;

[0007] S2: performing Nd isotope testing on whole rock to calculate an εNd(t) value of the whole rock;

[0008] S3: performing Sr isotope testing on the whole rock to calculate an ISr value of the whole rock;

[0009] S4: generating a scatter plot based on the εNd(t) value of the whole rock and the ISr value, and determining the εNd(t) values of the initial magma and the surrounding rock and the ISr values of the initial magma and the surrounding rock according to the range and composition trend of the scatter plot;

[0010] S5: using the AFC model, the initial magma in the process of quantitative simulation calculation of Sr-Nd isotope variation under the joint control of separation and contamination of surrounding rock;

[0011] S6: the εNd(t) value of the magma under different evolution processes calculated in S5 and the ISr scatter plot are generated to draw the AFC evolution trend line of the magma Sr-Nd isotope, and the data point of the sample to be tested is compared, and then the crustal component contamination proportion corresponding to the data point of the sample to be tested is read according to the calculation results of the quantitative simulation calculation in S5.

[0012] In a possible implementation, the crustal component contamination proportion in the initial magma is quantitatively estimated according to the trace element model shown in expressions (1) (3) (4) and the isotope model shown in expressions (2) (3) (4):

[0013]

[0014] z=(r+D-1) / (r-1) (3)

[0015] r=M a / M c (4)

[0016] wherein, C0is the trace element concentration in the original magma; C m Cis the trace element concentration of the magma in the AFC process; F is the trace element concentration of the surrounding rock; a is the ratio of residual magma mass M m and original magma mass ; D is the distribution coefficient between the crystalline mineral and the magma when the basic magma occurs crystallization and separation; r is the ratio of contamination rate and crystallization rate, and is also equal to the ratio of contamination mass M a and crystallization mass M c ;

[0017] wherein, ε0is the isotope composition of the original magma; ε m is the isotope composition of the magma in the AFC process; ε a is the isotope composition of the surrounding rock.

[0018] In a possible implementation, the step of using the AFC model to quantitatively simulate the Sr-Nd isotope variation of the initial magma under the joint control of separation crystallization and contamination of surrounding rock includes:

[0019] The crustal component contamination proportion in the initial magma is quantitatively estimated according to expression .

[0020] In a possible implementation, the initial magma and the country rock are determined in the following manner:

[0021] the sample with the lowest evolution degree in the magma series or the mantle end member as the initial magma;

[0022] and the representative crust source rock in the area where the sample is located as the country rock.

[0023] In a second aspect, embodiments of the present disclosure provide a device for determining the proportion of crustal component contamination in magma, comprising:

[0024] an age determination unit configured to determine the crystallization age t of the magma of the sample to be measured;

[0025] an isotope testing unit configured to perform Nd isotope testing on the whole rock to calculate the εNd(t) value of the whole rock, and perform Sr isotope testing on the whole rock to calculate the ISr value of the whole rock;

[0026] a numerical determination unit configured to generate a scatter plot based on the εNd(t) value of the whole rock and the ISr value, and determine the εNd(t) value of the initial magma and the country rock, and the ISr value of the initial magma and the country rock according to the range and composition trend of the scatter plot;

[0027] a simulation calculation unit configured to use the AFC model to quantitatively simulate the change of Sr-Nd isotopes of the initial magma under the joint control of the two processes of fractional crystallization and country rock contamination, and generate a scatter plot of the εNd(t) value and the ISr of the magma at different evolution processes calculated by the numerical determination unit, draw an AFC evolution trend line of the magma Sr-Nd isotopes, compare the data point of the sample to be measured, and read the proportion of crustal component contamination corresponding to the data point of the sample to be measured according to the calculation result of the quantitative simulation calculation.

[0028] In a possible implementation, the simulation calculation unit is specifically configured to:

[0029] quantitatively estimate the proportion of crustal component contamination in the initial magma according to the trace element model shown in expressions (1) (3) (4) and the isotope model shown in expressions (2) (3) (4):

[0030]

[0031] z = (r + D - 1) / (r - 1) (3)

[0032] r = M a / M c (4)

[0033] wherein, C is the concentration of trace elements in the original magma; m C is the concentration of trace elements in the original magma; a C is the concentration of trace elements in the original magma; m F is the concentration of trace elements in the wall rock; and F / M is the ratio of the residual magma mass M to the original magma mass M a D is the partition coefficient between the crystalline mineral and the magma when the basic magma undergoes crystallization separation; and r is the ratio of the contamination rate to the crystallization rate, and is also equal to the ratio of the contamination mass M c to the crystallization mass M

[0034] wherein, ε0 is the isotope composition of the original magma; m ε is the isotope composition of the original magma in the AFC process; a ε is the isotope composition of the wall rock.

[0035] In a possible implementation, the simulation calculation unit is specifically configured to quantitatively estimate the contamination proportion of the crust component in the initial magma according to the expression In a possible implementation, the simulation calculation unit is specifically configured to quantitatively estimate the contamination proportion of the crust component in the initial magma according to the expression

[0036] In a possible implementation, the simulation calculation unit is specifically configured to quantitatively estimate the contamination proportion of the crust component in the initial magma according to the expression

[0037] In a possible implementation, the simulation calculation unit is specifically configured to quantitatively estimate the contamination proportion of the crust component in the initial magma according to the expression

[0038] In a possible implementation, the simulation calculation unit is specifically configured to quantitatively estimate the contamination proportion of the crust component in the initial magma according to the expression

[0039] In a third aspect, an embodiment of the present disclosure provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory complete mutual communication through the communication bus;

[0040] The memory is used to store a computer program.

[0041] The processor is used to execute the program stored on the memory, and implement the method for determining the contamination proportion of the crust component in the magma.

[0042] In a fourth aspect, an embodiment of the present disclosure provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the method for determining the contamination proportion of the crust component in the magma.

[0043] The above technical solution provided by the embodiments of the present disclosure has at least some or all of the following advantages compared with the prior art:

[0044] Different crust-mantle source regions have significantly different Sr-Nd isotope values, so Sr-Nd isotopes are ideal for magma source tracing and determining the proportion of crustal contamination. The present disclosure takes magma Sr-Nd isotopes as carriers and provides a method for quantitatively simulating magma composition using an AFC model. The AFC model is used to quantitatively describe the effects of mineral separation and crystallization and crustal contamination on magma evolution, thereby realizing quantitative estimation of the proportion of crustal contamination in the AFC process. Moreover, whole-rock Sr-Nd isotope testing technology is mature, so the scheme provided by the present disclosure has important theoretical and application value for quantitative estimation of the proportion of crustal contamination in the AFC process. BRIEF DESCRIPTION OF DRAWINGS

[0045] The drawings incorporated in the specification and forming a part thereof illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or related description will be briefly introduced. Obviously, those drawings can also provide other drawings for those skilled in the art without creative labor.

[0047] Figure 1 A flowchart schematically showing a method for determining the proportion of crustal component contamination in magma according to an embodiment of the present disclosure is shown;

[0048] Figure 2 AFC evolution trend lines of magma Sr-Nd isotopes drawn according to an embodiment of the present disclosure are schematically shown;

[0049] Figure 3 A structural block diagram of a device for determining the proportion of crustal component contamination in magma according to an embodiment of the present disclosure is schematically shown; and

[0050] Figure 4 A structural block diagram of an electronic device according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0051] To make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present disclosure.

[0052] Since the scheme based on the two-end element mixing model provided by the prior art cannot realize true simulation of the two processes of fractional crystallization and crustal wall rock assimilation, and it is also difficult to determine the crustal component contamination ratio in the magma, the present disclosure provides a method and device for determining the crustal component contamination ratio in the magma to quantitatively estimate the two processes of fractional crystallization and crustal wall rock assimilation of the mantle source magma.

[0053] Firstly, the method for determining the crustal component contamination ratio in the magma provided by the present disclosure is described below.

[0054] Example One

[0055] Referring to Figure 1 The embodiment of the present disclosure provides a method for determining the crustal component contamination ratio in the magma, which comprises the following steps:

[0056] S1: dating the to-be-tested sample to obtain the crystallization age t of the magma of the to-be-tested sample;

[0057] S2: performing Nd isotope testing on the whole rock to calculate the εNd(t) value of the whole rock;

[0058] S3: performing Sr isotope testing on the whole rock to calculate the ISr value of the whole rock;

[0059] S4: generating a scatter plot based on the εNd(t) value and the ISr value of the whole rock, and determining the εNd(t) value of the initial magma and the wall rock and the ISr value of the initial magma and the wall rock according to the range and composition trend of the scatter plot;

[0060] S5: using the AFC model to quantitatively simulate and calculate the changes of Sr-Nd isotopes of the initial magma under the joint control of the two processes of fractional crystallization and wall rock contamination;

[0061] S6: generating a scatter plot of the εNd(t) value and the ISr of the magma at different evolution processes calculated in S5, drawing an AFC evolution trend line of the magma Sr-Nd isotopes, comparing with the data point of the to-be-tested sample, and reading the crustal component contamination ratio corresponding to the data point of the to-be-tested sample according to the calculation result of the quantitative simulation and calculation in S5.

[0062] In the embodiment, different mantle source regions have significantly different Sr-Nd isotope values, and therefore, Sr-Nd isotopes are ideal for magma source tracing and determining the proportion of crustal contamination. The present disclosure provides a method for quantitatively simulating magma composition by using an AFC model, based on the AFC model for quantitative description of mineral separation and crystallization and crustal contamination of two magma evolution processes, so as to quantitatively estimate the proportion of crustal contamination in the AFC process. Moreover, whole rock Sr-Nd isotope testing technology is mature, and therefore, the scheme provided by the present disclosure has important theoretical and application value for quantitatively estimating the proportion of crustal contamination in the AFC process.

[0063] In a possible implementation, the proportion of crustal component contamination in the initial magma can be quantitatively estimated according to the trace element model shown in expressions (1), (3), and (4) and the isotope model shown in expressions (2), (3), and (4):

[0064]

[0065] z = (r + D - 1) / (r - 1) (3)

[0066] r = M a / M c (4)

[0067] wherein, is the concentration of trace elements in the original magma; C m is the concentration of trace elements in the magma in the AFC process; C a is the concentration of trace elements in the surrounding rock; F is the ratio of the mass M m of the residual magma to the mass of the original magma ; D is the distribution coefficient between the crystalline mineral and the magma when the basic magma undergoes crystallization and separation; r is the ratio of the contamination rate to the crystallization rate, and is also equal to the ratio of the mass M a of the contamination to the mass M c of the crystallization;

[0068] wherein, is the isotope composition of the original magma, ε m is the isotope composition of the magma in the AFC process, ε a is the isotope composition of the surrounding rock.

[0069] In a possible implementation, the expression (2) can be derived according to the isotope model shown in the following expression: The derivation process is not described herein again.

[0070] Further, the step of using the AFC model to quantitatively simulate the variation of Sr-Nd isotopes of the initial magma under the joint control of the processes of fractional crystallization and contamination of surrounding rocks comprises the following steps:

[0071] According to the expression the proportion of the crustal component in the initial magma is quantitatively estimated.

[0072] In a possible implementation, the initial magma and the surrounding rock can be determined in the following manner: the sample with the lowest degree of evolution in the magma series or the mantle end member is taken as the initial magma; and the representative crustal source rock in the area where the sample is located is selected as the surrounding rock. It should be noted that this implementation is only a specific example of the present disclosure, and does not limit the manner of determining the initial magma and the surrounding rock of the present disclosure.

[0073] Example Two

[0074] The method for determining the proportion of the crustal component in the magma provided in Embodiment One will be described in detail below with reference to specific examples.

[0075] Step 1: The sample is dated to obtain the magma crystallization age t = 310 Ma.

[0076] Step 2: The whole rock is subjected to Nd isotope testing, and the calculated εNd(t) value of the whole rock ranges from 0.2 to 2.4.

[0077] Step 3: The whole rock is subjected to Sr isotope testing, and the calculated I Sr value of the whole rock ranges from 0.70230 to 0.70594.

[0078] Step 4: The whole rock εNd(t)-I Sr data of the sample are plotted, as shown in Table 1, the composition of the most primitive sample 6 is selected to represent the composition of the initial magma, and the representative rock Xilinhaote complex in the study area is selected as the upper crustal contamination component.

[0079] Table 1

[0080] Sample No. Isr eNd(t) 1 0.70570 0.4 2 0.70580 0.7 3 0.70594 0.2 4 0.70562 1 5 0.70558 1 6 0.70230 2.4

[0081] Initial magma composition (sample 6): Sr = 267.4, Nd = 9.4, Isr = 0.7023, εNd(t) = 2.4 Crustal surrounding rock composition (Xilinhaote complex): Sr = 250, Nd = 20, Isr = 0.715, εNd(t) = -10

[0082] Step 5: The Sr-Nd isotope evolution under three different conditions is calculated, which are as follows:

[0083] Model A: r = 0.5, DNd = 2, DSr = 0.1;

[0084] Model B: r = 0.3, DNd = 5, DSr = 0.1;

[0085] Model C: r = 0.2, DNd = 5, DSr = 0.1.

[0086] The Sr and Nd contents of the magma under different F processes in the AFC process, that is, the Cm(Sr) and Cm(Nd) values, are calculated by expression (1); the calculation results are brought into expression (2) to obtain the corresponding Sr and Nd isotope values, that is, εNdm and ISrm; and then the crustal material mixing ratio corresponding to different Sr and Nd isotope values is calculated by expression (5) The calculation results are shown in Table 2.

[0087] Table 2

[0088]

[0089]

[0090] Step 6: The calculation results are plotted into a scatter plot, and the AFC evolution trend line of the magma Sr-Nd isotope is drawn (see Figure 2 ), and the crustal component mixing ratio corresponding to the sample data points is obtained by comparison. The results show that the Baolida granite rock can be produced by 6-15% of crustal contamination.

[0091] As can be seen from the specific example, the method for quantitatively simulating the composition of magma provided by the disclosure based on the Sr-Nd isotope of magma as a carrier can quantitatively describe the two kinds of magma evolution effects of mineral separation crystallization and crustal contamination based on the AFC model, realize the quantitative estimation of the crustal contamination ratio in the AFC process, truly reflect the crustal contamination ratio, and greatly improve the drawbacks that the true situation of the crustal contamination ratio cannot be reflected when only the two end-member mixing model is used in the prior art.

[0092] The device for determining the crustal component mixing ratio in magma provided by the disclosure is described below.

[0093] Example Three

[0094] Referring to Figure 3 , the embodiment of the disclosure provides a device for determining the crustal component mixing ratio in magma, which comprises:

[0095] The dating unit 10 is used for dating the to-be-measured sample to obtain the crystallization age t of the magma of the to-be-measured sample.

[0096] The isotope testing unit 20 is used to perform Nd isotope testing on the whole rock and calculate the εNd(t) value of the whole rock; and to perform Sr isotope testing on the whole rock and calculate the ISr value of the whole rock.

[0097] The numerical determination unit 30 is used to generate a scatter plot based on the whole-rock εNd(t) value and the ISr value, and to determine the εNd(t) value of the initial magma and the surrounding rock, and the ISr value of the initial magma and the surrounding rock according to the range and composition trend of the scatter plot;

[0098] The simulation calculation unit 40 is used to quantitatively simulate and calculate the changes in Sr-Nd isotopes of the initial magma under the joint control of two processes: separation crystallization and surrounding rock contamination, using the AFC model; and to draw the AFC evolution trend line of magma Sr-Nd isotopes by plotting the εNd(t) values ​​and ISr generation scatter plots of the magma under different evolution processes calculated by the numerical determination unit 30, comparing them with the data points of the sample to be tested, and then reading the crustal component contamination ratio corresponding to the data points of the sample to be tested based on the calculation results of the quantitative simulation calculation.

[0099] In one possible implementation, the simulation calculation unit 40 is specifically used to quantitatively estimate the proportion of crustal components contaminating the initial magma according to the trace element model shown in expressions (1)(3)(4) and the isotope model shown in expressions (2)(3)(4):

[0100]

[0101] z=(r+D-1) / (r-1) (3)

[0102] r = M a / M c (4)

[0103] in, The concentration of trace elements in the original magma; C m C represents the trace element concentration of magma during the AFC process. a M represents the concentration of trace elements in the surrounding rock; F represents the mass of residual magma. m and the quality of the original magma The ratio of ; D is the partition coefficient between crystalline minerals and magma during crystallization separation in basic magma; r is the ratio of contamination rate to crystallization rate, which is also equal to the contamination mass M. a And crystal quality M c The ratio;

[0104] in, The isotopic composition of the original magma, ε m The isotopic composition of magma during the AFC process, εa isotopic composition of the country rock.

[0105] Further, the simulation calculation unit 40 is specifically configured to simulate the AFC process according to the expression quantitatively estimate the crustal contamination proportion in the initial magma.

[0106] Still further, the device for determining the crustal contamination proportion in the magma can further include a sample determination unit configured to determine the initial magma and the country rock in the following manner: specifically, the sample with the lowest evolution degree in the magma series or the mantle end member is taken as the initial magma; and the representative crust source rock in the region where the sample is located is selected as the country rock.

[0107] In the embodiment, different crust-mantle source regions have significantly different Sr-Nd isotopic values, and therefore, the Sr-Nd isotopes are ideal objects for magma source tracing and determining the crustal contamination proportion. The present disclosure takes the magma Sr-Nd isotopes as carriers and provides a method for quantitatively simulating the magma composition by using the AFC model. The AFC model is used to quantitatively describe the two magma evolution processes of mineral separation crystallization and crustal contamination, so as to quantitatively estimate the crustal contamination proportion in the AFC process. Moreover, the whole-rock Sr-Nd isotope testing technology is mature, and therefore, the scheme provided by the present disclosure has important theoretical and application values for quantitatively estimating the crustal contamination proportion in the AFC process.

[0108] The following is one application scenario of the device for determining the crustal contamination proportion in the magma in the embodiment, wherein the device for determining the crustal contamination proportion in the magma includes:

[0109] The dating unit 10 is configured to date the sample to obtain the magma crystallization age t = 310 Ma.

[0110] The isotopic testing unit 20 is configured to perform Nd isotope testing on the whole rock to calculate the εNd(t) value range of the whole rock as 0.2-2.4, and perform Sr isotope testing on the whole rock to calculate the I Sr value range of the whole rock as 0.70230-0.70594.

[0111] The numerical determination unit 30 is configured to plot the whole rock εNd(t)-I Sr data of the sample into a scatter plot, refer to Table 1, select the composition of the most original sample 6 to represent the original magma composition, and select the representative rock Xilinhaote complex in the study region as the upper crustal contamination component.

[0112] Table 1

[0113] Sample No. Isr eNd(t) 1 0.70570 0.4 2 0.70580 0.7 3 0.70594 0.2 4 0.70562 1 5 0.70558 1 6 0.70230 2.4

[0114] Original magma composition (sample 6): Sr = 267.4, Nd = 9.4, Isr = 0.7023, εNd(t) = 2.4 Crustal wall rock composition (Xilingol complex): Sr = 250, Nd = 20, Isr = 0.715, εNd(t) = -10

[0115] Step 5: Calculate the Sr-Nd isotope evolution under three different conditions, respectively:

[0116] Model A: r = 0.5, DNd = 2, DSr = 0.1;

[0117] Model B: r = 0.3, DNd = 5, DSr = 0.1;

[0118] Model C: r = 0.2, DNd = 5, DSr = 0.1.

[0119] The Sr and Nd contents of the magma under different F processes in the AFC process, that is, the Cm(Sr) and Cm(Nd) values, are calculated from expression (1); the calculation results are brought into expression (2) to obtain the corresponding Sr and Nd isotope values, that is, εNdm and ISrm; and the corresponding crustal material contamination ratios of different Sr and Nd isotope values are calculated from expression (5) The calculation results are shown in Table 2.

[0120] Table 2

[0121]

[0122]

[0123] The simulation calculation unit 40 is used to scatter the calculation results into a dot plot and draw the AFC evolution trend line of the magma Sr-Nd isotope (see Figure 2 ), and compare with the sample data points to obtain the crustal component contamination ratio corresponding to the sample data points. The results show that the Baolida granite rock can be produced by 6-15% of crustal contamination.

[0124] The implementation processes of the functions and roles of the various units in the above device are specifically described in the implementation processes of the corresponding steps in the above method, and will not be repeated here.

[0125] For the apparatus embodiment, since it basically corresponds to the method embodiment, the relevant part is described in the part of the method embodiment. The apparatus embodiment described above is only illustrative, wherein the units described as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, i.e., can be located in one place or distributed on multiple network units. Part or all of the modules can be selected to achieve the purpose of the present application according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0126] In the above embodiments, any multiple of the dating unit 10, the isotope testing unit 20, the numerical determination unit 30 and the simulation calculation unit 40 can be combined in one module, or any one of the modules can be split into multiple modules. Alternatively, at least part of the function of one or more of the modules can be combined with at least part of the function of the other modules and implemented in one module. At least one of the dating unit 10, the isotope testing unit 20, the numerical determination unit 30 and the simulation calculation unit 40 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or any other reasonable way of integrating or packaging circuits, etc. hardware or firmware, or any one of software, hardware and firmware or any appropriate combination of several of them. Alternatively, at least one of the dating unit 10, the isotope testing unit 20, the numerical determination unit 30 and the simulation calculation unit 40 can be at least partially implemented as a computer program module which can perform the corresponding function when it is run.

[0127] Example Four

[0128] Based on the same inventive concept, referring to Figure 4 The third exemplary embodiment of the present disclosure provides an electronic device, which includes a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120 and the memory 1130 complete communication with each other through the communication bus 1140;

[0129] The memory 1130 is used to store a computer program;

[0130] The processor 1110 is used to execute the program stored in the memory 1130, and implement the method for determining the crust component contamination ratio in magma as shown below:

[0131] S1: dating the sample to be tested to obtain the crystallization age t of the magma of the sample to be tested;

[0132] S2: performing Nd isotope testing on the whole rock to calculate the value of εNd(t) of the whole rock;

[0133] S3: performing Sr isotope testing on the whole rock to calculate the value of ISr of the whole rock;

[0134] S4: generating a scatter plot based on the value of εNd(t) of the whole rock and the value of ISr, and determining the value of εNd(t) of the initial magma and the wall rock and the value of ISr of the initial magma and the wall rock according to the range and composition trend of the scatter plot;

[0135] S5: using the AFC model to quantitatively simulate and calculate the changes of Sr-Nd isotopes of the initial magma under the joint control of the processes of fractional crystallization and wall rock contamination;

[0136] S6: generating a scatter plot of the values of εNd(t) and ISr of the magma under different evolution processes calculated in S5, drawing an AFC evolution trend line of the Sr-Nd isotopes of the magma, comparing with the data point of the sample to be tested, and reading the crustal component contamination proportion corresponding to the data point of the sample to be tested according to the calculation results of the quantitative simulation and calculation in S5.

[0137] In a possible implementation, the processor 1110, when executing the program stored on the memory 1130, also implements the method for determining the crustal component contamination proportion in the magma as shown below:

[0138] The crustal component contamination proportion in the initial magma is quantitatively estimated according to the trace element model shown in expressions (1) (3) (4) and the isotope model shown in expressions (2) (3) (4):

[0139]

[0140] z = (r + D - 1) / (r - 1) (3)

[0141] r = M a / M c (4)

[0142] wherein, C is the concentration of trace elements in the original magma; C m C is the concentration of trace elements in the magma in the AFC process; C a F is the concentration of trace elements in the wall rock; F is the mass of the residual magma M m and the mass of the original magma D is the partition coefficient between the crystalline mineral and the magma when the basic magma is undergoing crystallization separation; r is the ratio of the contamination rate and the crystallization rate, and is equal to the contamination mass M a and the crystallization mass M c ;

[0143] wherein, is the isotopic composition of the original magma, ε m is the isotopic composition of the magma in the AFC process, ε a is the isotopic composition of the wall rock.

[0144] In one possible implementation, the processor 1110, when executing the program stored on the memory 1130, also implements the method for determining the proportion of the crustal component contamination in the magma as shown below:

[0145] The proportion of the crustal component contamination in the initial magma is quantitatively estimated according to the expression .

[0146] In one possible implementation, the processor 1110, when executing the program stored on the memory 1130, also implements the method for determining the proportion of the crustal component contamination in the magma as shown below:

[0147] The sample with the lowest degree of evolution in the magma series or the mantle end member is selected as the initial magma.

[0148] In addition, the representative crustal source rock in the area where the sample is located is selected as the wall rock.

[0149] In one possible implementation, the processor 1110, when executing the program stored on the memory 1130, also implements the method for determining the proportion of the crustal component contamination in the magma as shown below:

[0150] Step 1: The sample is dated to obtain the magma crystallization age t = 310 Ma.

[0151] Step 2: The whole rock is subjected to Nd isotope testing, and the calculated εNd(t) value of the whole rock ranges from 0.2 to 2.4.

[0152] Step 3: The whole rock is subjected to Sr isotope testing, and the calculated I Sr value of the whole rock ranges from 0.70230 to 0.70594.

[0153] Step 4: The whole rock εNd(t)-I Sr data of the sample are plotted into a scatter plot, see Table 1, the composition of the most primitive sample 6 is selected to represent the composition of the original magma, and the representative rock Xilinhaote complex in the study area is selected as the upper crustal contamination component.

[0154] Table 1

[0155] Sample No. Isr eNd(t) 1 0.70570 0.4 2 0.70580 0.7 3 0.70594 0.2 4 0.70562 1 5 0.70558 1 6 0.70230 2.4

[0156] Original magma composition (sample 6): Sr = 267.4, Nd = 9.4, Isr = 0.7023, εNd(t) = 2.4 Crustal wall rock composition (Xilingol complex): Sr = 250, Nd = 20, Isr = 0.715, εNd(t) = -10

[0157] Step 5: Calculate the Sr-Nd isotope evolution under three different conditions, respectively:

[0158] Model A: r = 0.5, DNd = 2, DSr = 0.1;

[0159] Model B: r = 0.3, DNd = 5, DSr = 0.1;

[0160] Model C: r = 0.2, DNd = 5, DSr = 0.1.

[0161] The Sr and Nd contents of the magma under different F processes in the AFC process, i.e. Cm(Sr) and Cm(Nd) values, are calculated from expression (1); the calculation results are brought into expression (2) to obtain the corresponding Sr and Nd isotope values, i.e. εNdm and ISrm; and then the crustal material mixing ratio corresponding to different Sr and Nd isotope values is calculated from expression (5) The calculation results are shown in Table 2.

[0162] Table 2

[0163]

[0164]

[0165] Step 6: The calculation results are plotted into scatter plots, and the AFC evolution trend lines of the magma Sr-Nd isotope are drawn (see Figure 2 ), and compared with the sample data points to obtain the crustal composition mixing ratio corresponding to the sample data points. The results show that the Baolida granite rock can be produced by 6-15% of crustal contamination.

[0166] The communication bus 1140 described above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus 1140 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is shown in the figure, but it does not mean that there is only one bus or only one type of bus.

[0167] The communication interface 1120 is configured to communicate between the electronic device described above and other devices.

[0168] The memory 1130 can include a Random Access Memory (RAM) and can also include a non-volatile memory, such as at least one disk memory. Optionally, the memory 1130 can also be at least one storage device located away from the aforementioned processor 1110.

[0169] The processor 1110 described above can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component.

[0170] Example Five

[0171] Based on the same inventive concept, the fourth exemplary embodiment of the present disclosure also provides a computer readable storage medium. The computer readable storage medium described above stores a computer program, and the computer program is executed by a processor to implement the method for determining the crust component contamination ratio in magma as described above.

[0172] The computer readable storage medium can be included in the device / apparatus described in the above embodiments; or can exist separately and not be assembled into the device / apparatus. The computer readable storage medium described above carries one or more programs, and when the one or more programs are executed, the method for determining the crust component contamination ratio in magma according to the embodiments of the present disclosure is implemented:

[0173] S1: dating the sample to be tested to obtain the crystallization age t of the magma of the sample to be tested;

[0174] S2: performing Nd isotope testing on the whole rock to obtain the εNd(t) value of the whole rock;

[0175] S3: performing Sr isotope testing on the whole rock to obtain the ISr value of the whole rock;

[0176] S4: generating a scatter plot based on the εNd(t) value of the whole rock and the ISr value, and determining the εNd(t) value of the initial magma and the wall rock and the ISr value of the initial magma and the wall rock according to the range and composition trend of the scatter plot;

[0177] S5: using the AFC model to quantitatively simulate and calculate the changes of Sr-Nd isotopes of the initial magma under the joint control of the processes of fractional crystallization and wall rock contamination;

[0178] S6: generating a scatter plot of the εNd(t) value and the ISr of the magma under different evolution processes calculated in S5, drawing an AFC evolution trend line of the magma Sr-Nd isotopes, comparing with the data point of the sample to be tested, and reading the crustal component contamination proportion corresponding to the data point of the sample to be tested according to the calculation results of the quantitative simulation and calculation in S5.

[0179] In the embodiment, different crust-mantle source regions have significantly different Sr-Nd isotope values, and therefore, Sr-Nd isotopes are ideal objects for magma source tracing and determining the crustal contamination proportion. The present disclosure takes magma Sr-Nd isotopes as carriers, and provides a method for quantitatively simulating magma components by using the AFC model. The AFC model is used to quantitatively describe the two magma evolution processes of mineral fractional crystallization and crustal contamination, so as to realize quantitative estimation of the crustal contamination proportion in the AFC process. Moreover, the whole rock Sr-Nd isotope testing technology is mature, and therefore, the scheme provided by the present disclosure has important theoretical and application values for quantitative estimation of the crustal contamination proportion in the AFC process.

[0180] In a possible implementation, when the one or more programs are executed, a method for determining the crustal component contamination proportion in magma according to the embodiments of the present disclosure is implemented:

[0181]

[0182] z = (r + D - 1) / (r - 1) (3)

[0183] r = M a / M c (4)

[0184] wherein, C is the trace element concentration in the original magma; C m C is the trace element concentration in the original magma; C a F is the trace element concentration in the wall rock; F is the residual magma mass M m and the original magma mass D is the partition coefficient between the crystalline mineral and the magma when the basic magma undergoes crystallization separation; r is the ratio of the contamination rate to the crystallization rate, and is also equal to the ratio of the contamination mass M a and the crystallization mass M c ;

[0185] wherein, εi is the isotope composition of the original magma, ε m εi is the isotope composition of the original magma, ε a εi is the isotope composition of the original magma, ε

[0186] In one possible implementation, when the one or more programs are executed, the method for determining the crust component contamination ratio in the magma according to the embodiments of the present disclosure is implemented as follows: according to the isotope model shown in the following expression, the expression (2) is derived, The derivation process is not described here again.

[0187] In one possible implementation, when the one or more programs are executed, the method for determining the crust component contamination ratio in the magma according to the embodiments of the present disclosure is implemented as follows:

[0188] According to the expression the crust component contamination ratio in the initial magma is quantitatively estimated.

[0189] In one possible implementation, when the one or more programs are executed, the method for determining the crust component contamination ratio in the magma according to the embodiments of the present disclosure is implemented as follows: taking the sample with the lowest evolution degree in the magma series or the mantle end member as the initial magma; and selecting the representative crust source rock in the region where the sample is located as the wall rock.

[0190] According to the embodiments of the present disclosure, the computer readable storage medium can be a non-volatile computer readable storage medium, which can include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, the computer readable storage medium can be any tangible medium containing or storing a program, which can be used by or in conjunction with an instruction execution system, device or apparatus.

[0191] It has to be noted that, in the present document, relational terms are intended to encompass the various possible relationships between alternatives, such as those individuals or entities that have been discussed in the foregoing description. For example, without limitation, the term "first" can mean "second", and vice versa; the term "second" can mean "first", and vice versa; the term "at least one of' can mean "one", "two", "three", or more; the term "one or more" can mean "one", "two", "three", or more; the term "top" can mean "bottom"; the term "bottom" can mean "top"; the term "front" can mean "back"; the term "back" can mean "front"; and the like. Also, the terms "comprise", "comprising", "comprises", "include", "including", "includes", "contain", "containing", "has", "having", or "has" and / or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, includes, contains a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "a", "an" and "the" herein mean "one or more".

[0192] The foregoing description of the exemplary embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the disclosure be limited only by the claims and equivalents thereof.

Claims

1. A method for determining the proportion of crustal components contaminating magma, characterized in that, The method includes: S1: Dating the sample to be tested to obtain the crystallization age t of the magma in the sample; S2: Perform Nd isotope analysis on the whole rock and calculate the εNd(t) value of the whole rock; S3: Perform Sr isotope analysis on the whole rock and calculate the ISr value of the whole rock; S4: Generate a scatter plot based on the whole-rock εNd(t) value and the ISr value, and determine the εNd(t) value of the initial magma and the surrounding rock, and the ISr value of the initial magma and the surrounding rock according to the range and composition trend of the scatter plot; S5: Using the AFC model, quantitative simulation calculations were performed on the changes in Sr-Nd isotopes of the initial magma under the combined control of two processes: separation crystallization and contamination of the surrounding rock. S6: Plot the εNd(t) values ​​and ISr generation scatter plots of magma under different evolution processes obtained from S5, and draw the AFC evolution trend line of magma Sr-Nd isotopes. Compare it with the data points of the sample to be tested, and then read the crustal component contamination ratio corresponding to the data points of the sample to be tested according to the calculation results of the quantitative simulation calculation in S5.

2. The method for determining the proportion of crustal components in magma according to claim 1, characterized in that, The proportion of crustal components in the initial magma was quantitatively estimated according to the trace element model shown in expressions (1)(3)(4) and the isotope model shown in expressions (2)(3)(4): z=(r+D-1) / (r-1) (3) r= M a / M c (4) in, The concentration of trace elements in the original magma; C m C represents the trace element concentration of magma during the AFC process. a M represents the concentration of trace elements in the surrounding rock; F represents the mass of residual magma. m and the quality of the original magma The ratio of ; D is the partition coefficient between crystalline minerals and magma during crystallization separation in basic magma; r is the ratio of contamination rate to crystallization rate, which is also equal to the contamination mass M. a And crystal quality M c The ratio; in, The isotopic composition of the original magma, ε m The isotopic composition of magma during the AFC process, ε a It represents the isotopic composition of the surrounding rock.

3. The method for determining the proportion of crustal components in magma according to claim 2, characterized in that, The steps of using the AFC model to quantitatively simulate and calculate the Sr-Nd isotope changes of the initial magma under the joint control of two processes: fractional crystallization and wall rock contamination, include: According to the expression The proportion of crustal components contaminating the initial magma was quantitatively estimated.

4. The method for determining the proportion of crustal components contaminating magma according to any one of claims 1 to 3, characterized in that, The initial magma and surrounding rock were determined as follows: The initial magma was the sample with the lowest degree of evolution in the magma series or the mantle end-member. Additionally, representative crustal rocks within the sample area were selected as the surrounding rocks.

5. An apparatus for determining the proportion of crustal components contaminating magma, characterized in that, include: The dating unit is used to date the sample to be tested, and to obtain the crystallization age t of the magma in the sample to be tested; The isotope testing unit is used to perform Nd isotope testing on the whole rock and calculate the εNd(t) value of the whole rock. In addition, Sr isotope analysis was performed on the whole rock to calculate the ISr value of the whole rock; The numerical determination unit is used to generate a scatter plot based on the whole-rock εNd(t) value and the ISr value, and to determine the εNd(t) value of the initial magma and the surrounding rock, and the ISr value of the initial magma and the surrounding rock according to the range and composition trend of the scatter plot; The simulation calculation unit is used to quantitatively simulate and calculate the changes in Sr-Nd isotopes of the initial magma under the joint control of two processes: separation crystallization and surrounding rock contamination, using the AFC model. It then uses the εNd(t) values ​​and ISr generation scatter plots of the magma under different evolutionary stages calculated by the numerical determination unit to plot the AFC evolution trend line of the magma's Sr-Nd isotopes. This trend line is compared with the data points of the sample to be tested. Finally, based on the calculation results of the quantitative simulation, the crustal contamination ratio corresponding to the data points of the sample to be tested is read.

6. The apparatus for determining the proportion of crustal components in magma according to claim 5, characterized in that, The simulation calculation unit is specifically used for: The proportion of crustal components in the initial magma was quantitatively estimated according to the trace element model shown in expressions (1)(3)(4) and the isotope model shown in expressions (2)(3)(4): z=(r+D-1) / (r-1) (3) r= M a / M c (4) in, The concentration of trace elements in the original magma; C m C represents the trace element concentration of magma during the AFC process. a M represents the concentration of trace elements in the surrounding rock; F represents the mass of residual magma. m and the quality of the original magma The ratio of ; D is the partition coefficient between crystalline minerals and magma during crystallization separation in basic magma; r is the ratio of contamination rate to crystallization rate, which is also equal to the contamination mass M. a And crystal quality M c The ratio; in, The isotopic composition of the original magma, ε m The isotopic composition of magma during the AFC process, ε a It represents the isotopic composition of the surrounding rock.

7. The apparatus for determining the proportion of crustal components in magma according to claim 6, characterized in that, The simulation calculation unit is specifically used to calculate according to the expression The proportion of crustal components contaminating the initial magma was quantitatively estimated.

8. The apparatus for determining the proportion of crustal components contaminating magma according to any one of claims 5 to 7, characterized in that, It also includes a sample determination unit for determining the initial magma and surrounding rock in the following manner: The initial magma was the sample with the lowest degree of evolution in the magma series or the mantle end-member. Additionally, representative crustal rocks within the sample area were selected as the surrounding rocks.

9. An electronic device, characterized in that, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the method for determining the proportion of crustal components in magma according to any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for determining the proportion of crustal components in magma as described in any one of claims 1-4.

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