A sediment dating correction method and system
By combining the AMS14C dating method and 210Pb isotope analysis, the problem of inaccurate correction in sediments lacking foraminifera was solved, and accurate sediment measurement was achieved, and the reliability and accuracy of dating were improved.
Patent Information
- Application Number
- CN202311745543.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-19
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2043-12-19
AI Technical Summary
In the lack of foraminiferous sediments, the traditional 14C dating method has aged due to the inclusion of ‘old carbon’, and cannot accurately correct the chronology.
The AMS14C dating method combined with 210Pb isotope analysis was used to measure the AMS14C dating data and the attenuation equilibrium of 210Pb of each layer of the sediment, and the correction value of the ‘old carbon’ was determined, and the chronological framework was constructed by determining the deposition rate to achieve accurate chronological measurement of the sediment.
Improve the reliability and accuracy of sediment 14C dating lacking foraminifera, fills the gaps in the prior art, and reduces the cost and difficulty of chronological measurements.
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Figure CN117741733B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sediment age measurement, and in particular to a sediment age measurement correction method and system. Background Art
[0002] Accurate chronological data is the basis and core for reconstructing past human activities and climate and environmental changes. 14 C dating is a method widely used in geology and archaeology that measures the radioactive carbon isotopes in sediments. 14 C content to determine the age of the sample. However, the current sediment 14 The C dating method mainly relies on the presence of foraminifera. In some specific environments, such as alpine lakes, glaciers and deserts, sediments lacking foraminifera are used to obtain carbon samples. 14 C dating, the dating results are too old because of the mixing of "old carbon", so the traditional 14 C dating method for accurate age correction. Summary of the invention
[0003] In order to solve the above problems existing in the prior art, the present invention provides a sediment dating correction method and system.
[0004] To achieve the above object, the present invention provides the following solutions:
[0005] A sediment dating correction method, comprising:
[0006] Adopting AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data;
[0007] For the shallow surface of the sediment to be tested 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb attenuation with sediment depth;
[0008] use 210 The uniformity of Pb attenuation with sediment depth is used to measure the AMS of the shallow surface of the sediment to be tested, taking the shallow surface of the sediment to be tested as the modern sedimentary layer. 14 C dating data;
[0009] AMS for shallow sediment layers to be tested 14 C dating data and AMS 14 AMS of the shallow surface layer of the sediment to be tested obtained by C dating method 14 C dating data are interpolated to obtain the correction value of "old carbon";
[0010] Except for the shallow surface layer of sediment to be measured, the AMS14 The “old carbon” correction value is subtracted from the C dating data to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C calendar year value;
[0011] Based on the AMS after correction of two adjacent layers in the sediment to be measured 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate;
[0012] Determine the AMS of the sediment between two adjacent layers according to the deposition rate 14 C calendar year value;
[0013] Determine the AMS of the sediments outside the adjacent two layers based on the sedimentation rate 14 C calendar year value;
[0014] According to the AMS calibrated for each layer of sediment to be measured 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
[0015] Optionally, use AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data, including:
[0016] Obtaining sediment samples from each layer of the sediment to be tested, and converting acid-insoluble organic carbon in the sediment samples into graphite;
[0017] The graphite is gasified, and carbon atoms in the gasified graphite are separated by an accelerator, and the separated carbon atoms are received by a Faraday cup at different positions of the accelerator track; the carbon atoms include 12 C. 13 C and 14 C;
[0018] Based on the received separated carbon atoms 14 C / 12 The value of C or 14 C / 13 The value of C is to achieve 14 C measurement to obtain the AMS of each layer of the sediment to be tested 14 C dating data.
[0019] Optionally, the shallow surface layer of the sediment to be tested 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb attenuation with sediment depth includes:
[0020] Take a set weight of the sediment to be tested, grind it and pass it through a 100-mesh sieve to obtain a sample powder;
[0021] The sample powder is placed in a sample tube, sealed and placed for a set number of days;
[0022] Use ORTEC high purity germanium well probe to probe into the sample tube containing the sample powder for radioisotope measurement and analysis 210 Pb decays exponentially with increasing depth according to the law of radioactive decay until 210 When the change in the value of Pb tends to be relatively stable, we get 210 The uniformity of Pb decay with sediment depth.
[0023] Optionally, the AMS of the deposit between two adjacent layers is determined based on the deposition rate by interpolation. 14 C Calendar year value.
[0024] Optionally, the AMS of the sediment outside the two adjacent layers is determined based on the deposition rate by extrapolation. 14 C Calendar year value.
[0025] Furthermore, the present invention also provides a sediment dating correction system, which is used to implement the sediment dating correction method provided above; the system comprises:
[0026] The first dating module for the AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data;
[0027] The equilibrium determination module is used to determine the shallow surface layer of the sediment to be tested. 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb attenuation with sediment depth;
[0028] The second dating module is used to 210 The uniformity of Pb attenuation with sediment depth is used to measure the AMS of the shallow surface of the sediment to be tested, taking the shallow surface of the sediment to be tested as the modern sedimentary layer. 14 C dating data;
[0029] Correction value determination module for AMS of shallow sediment layers to be measured 14 C dating data and AMS 14 AMS of the shallow surface layer of the sediment to be tested obtained by C dating method 14 C dating data are interpolated to obtain the correction value of "old carbon";
[0030] The dating data correction module is used to correct the AMS data of other layers except the shallow surface layer of the sediment to be measured.14 The “old carbon” correction value is subtracted from the C dating data to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C calendar year value;
[0031] Sedimentation rate determination module, used to determine the AMS based on the correction of two adjacent layers in the sediment to be measured 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate;
[0032] The third dating module is used to determine the AMS of the sediments between two adjacent layers according to the deposition rate. 14 C calendar year value;
[0033] The fourth dating module is used to determine the AMS of sediments outside the adjacent two layers based on the deposition rate. 14 C calendar year value;
[0034] Chronological framework building module for AMS calibrated according to the sediment layers to be measured 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
[0035] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:
[0036] 1. Applying the sediment dating correction method provided by the present invention to sediments lacking foraminifera 14 When calibrating the age of C dating, it can fill the gaps in existing technology.
[0037] 2. The present invention analyzes the total carbon content of sediments 14 C dating data and 210 Pb isotope data can accurately infer the age of sediments lacking foraminifera, improving the 14 Reliability and accuracy of C dating.
[0038] 3. The present invention is simple and easy to implement, does not require additional equipment and complicated experimental operations, and reduces the cost and implementation difficulty of sediment age measurement. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0040] Figure 1 The present invention provides a flow chart of the sediment dating correction method. DETAILED DESCRIPTION
[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0042] The purpose of the present invention is to provide a method and system for calibrating the age of sediments lacking foraminifera, which can accurately infer the age of sediments lacking foraminifera and improve the accuracy of sediments. 14 The reliability and accuracy of C dating are improved, and no additional equipment and complicated experimental operations are required, which can reduce the cost and difficulty of measuring sediment age.
[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0044] The present invention utilizes the "substitution" principle in TRIZ and analyzes the sediment full carbon sample and 210 The isotopic content of Pb is used to replace the traditional reliance on foraminifera sediments 14 C dating method. This alternative idea is creative and can solve the problem that traditional methods cannot accurately date sediments that lack foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between isotope content and age, and uses interpolation calculation methods to achieve accurate age correction of the sediments to be measured.
[0045] like Figure 1 As shown, the sediment dating correction method provided by the present invention comprises:
[0046] Step 100: Adopt AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data.
[0047] In practical applications, AMS of all carbon in columnar sediments can be performed. 14 C dating experiment to obtain the AMS of each layer of the sediment to be tested 14 C dating data, specific:
[0048] The acid-insoluble organic carbon in the sediment sample is first converted into graphite, and then the graphite is gasified and passed through an accelerator to remove impurity particles, strip electrons, accelerate positrons, and achieve 12 C. 13 C and 14 C these carbon atoms are separated, and finally the carbon atoms are received by Faraday cups at different positions in the accelerator orbit, and then the 14 C / 12 C value or 14 C / 13 The value of C is then realized 14 C measurement to obtain the AMS of the sediment to be tested 14 C dating data.
[0049] Step 101: The shallow surface of the sediment to be tested 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb decay with sediment depth.
[0050] In the actual application process, the shallow surface layer of columnar sediments was experimentally tested. 210 The isotope analysis of Pb was carried out to obtain 210 The experiment of the uniformity of Pb attenuation with sediment depth was conducted in accordance with the National Standard of the People's Republic of China "Determination of Radionuclides in Marine Sediments by Gamma Spectrometry (GB / T 30738-2014)".
[0051] Take a set weight (e.g. 10g) of dry sediment, grind it, pass it through a 100-mesh sieve to remove plant roots, and then put it into a sample tube, seal it, and leave it for a set number of days (e.g. 20 days). Then use ORTEC high-purity germanium well probe (GWL-120-15N) to measure radioactive isotopes. The measurement time for each sample is generally 1 to 3 days, total 210 The specific activity of Pb is 46.5keV ( 210 Pb) energy, background 210 The specific activity of Pb is 351keV ( 214 Pb, 226 The peak area at the energy of Ra daughter) is calculated, and the excess 210 The specific activity of Pb is 210 Specific activity and background of Pb 210 The difference in specific activity of Pb. 210 Pb decays exponentially with increasing depth according to the law of radioactive decay. 210 Pb belongs to the uranium series decay nuclide, with a half-life of 22.3 years. It is commonly used in sediment dating. 210 After about 7 half-lives, the intensity of Pb nuclides decays to about 1% of the initial value, making it difficult to be accurately detected by instruments.210 The upper limit of Pb dating is about 150 years. 210 Pb total It consists of two parts, one of which comes from the accumulation in the sediment. 226 Ra decays naturally 210 Pb, called compensated 210 Pb, and the other part comes from sedimentation 210 Pb, called excess 210 Pb, that is 210 Pb ex . 226 Ra and 210 Pb belongs to 238 U decay series nuclides can be 226 Ra and 210 Pb is considered as a pair of mother and child. Assume 226 Ra and 210 Pb has no other input and output. After the decay of these two nuclides reaches equilibrium at a certain depth, the excess 210 Pb will become a relatively stable value, and the part above this depth can be identified as having the properties of modern sedimentation.
[0052] Step 102: Exploitation 210 The uniformity of Pb attenuation with sediment depth is used to measure the AMS of the shallow surface of the sediment to be tested, taking the shallow surface of the sediment to be tested as the modern sedimentary layer. 14 C dating data.
[0053] Step 103: AMS of the shallow surface of the sediment to be tested 14 C dating data and AMS 14 AMS of the shallow surface layer of the sediment to be tested obtained by C dating method 14 C dating data are interpolated to obtain the correction value of "old carbon".
[0054] Step 104: AMS of other layers except the shallow surface layer of the sediment to be measured 14 The C dating data are all deducted from the "old carbon" correction value to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C Calendar year value.
[0055] Steps 102 to 104 are to utilize the shallow surface sediments in step 101 210 The uniformity of Pb attenuation with depth determines the modern sedimentary layer (0cal BP) and measures its AMS 14 C dating data, and based on the AMS measured in steps 100 and 102 14 The interpolation of C dating data yields the correction value of “old carbon”. The AMS of other layers 14The C value is subtracted from the "old carbon" correction value to achieve a more corrected AMS value for each layer of the sediment to be measured. 14 C Calendar year value.
[0056] Step 105: AMS calibrated based on two adjacent layers in the sediment to be measured 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate.
[0057] Step 106: Determine the AMS of the deposits between two adjacent layers based on the deposition rate 14 C calendar year value. Among them, the part between two horizons is interpolated to calculate its corresponding AMS according to the sedimentation rate. 14 C Calendar year value.
[0058] Step 107: Determine the AMS of the sediment outside the two adjacent layers based on the sedimentation rate 14 C calendar year value. Among them, the corresponding AMS is calculated by extrapolation outside the two layers. 14 C calendar year values, in order to achieve the interpolation and data extension of calendar year values, so as to facilitate the subsequent establishment of the chronological framework.
[0059] Step 108: AMS calibrated according to the sediment layers to be measured 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
[0060] Based on the above description, the present invention is based on 210 Pb is widely present in the natural environment, with a half-life of 22.3 years. 210 Pb decays exponentially with increasing depth according to the law of radioactive decay, reaching equilibrium at a certain depth, and it is believed that the deposits above this depth are within 150 years. 14 The half-life of C dating 5730a and its error of tens to hundreds of years, 210 The sedimentary layer before Pb reaches equilibrium can be regarded as modern material, and the age value is determined to be 0 Cal a BP. 14 The value measured by C is used as the error value of "old carbon" to correct all 14 C dating data, and then establish the chronological framework of the calendar year.
[0061] Based on this, the present invention utilizes the "substitution" principle in TRIZ and analyzes the sediment full carbon samples and 210 The isotopic content of Pb is used to replace the traditional reliance on foraminifera sediments 14C dating method. This alternative idea can solve the problem that traditional methods cannot accurately date sediments lacking foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between isotope content and age, and uses interpolation calculation methods to achieve accurate age correction of the sample to be tested.
[0062] Furthermore, the present invention also provides a sediment dating correction system, which is used to implement the sediment dating correction method provided above. The system includes: a first dating module, a uniformity determination module, a second dating module, a correction value determination module, a dating data correction module, a sedimentation rate determination module, a third dating module, a fourth dating module and a chronological framework construction module.
[0063] The first dating module was used to 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data.
[0064] The equilibrium determination module is used to determine the shallow surface layer of the sediment to be tested. 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb decay with sediment depth.
[0065] The second dating module is used to 210 The uniformity of Pb attenuation with sediment depth is used to measure the AMS of the shallow surface of the sediment to be tested, taking the shallow surface of the sediment to be tested as the modern sedimentary layer. 14 C dating data.
[0066] The correction value determination module is used for the AMS of the shallow surface of the sediment to be tested. 14 C dating data and AMS 14 AMS of the shallow surface layer of the sediment to be tested obtained by C dating method 14 C dating data are interpolated to obtain the correction value of "old carbon".
[0067] The dating data correction module is used to correct the AMS data of other layers except the shallow surface layer of the sediment to be measured. 14 The C dating data are all deducted from the "old carbon" correction value to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C Calendar year value.
[0068] The sedimentation rate determination module is used to determine the AMS value based on the correction of two adjacent layers in the sediment to be measured. 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate.
[0069] The third dating module is used to determine the AMS of sediments between two adjacent layers based on the sedimentation rate. 14 C Calendar year value.
[0070] The fourth dating module is used to determine the AMS of sediments beyond the two adjacent layers based on the sedimentation rate. 14 C Calendar year value.
[0071] The chronological framework building module is used to calibrate the AMS data according to the sediment layers to be measured. 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
[0072] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.
[0073] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.
Claims
1. A sediment dating correction method, characterized in that: include: Adopting AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data; For the shallow surface of the sediment to be tested 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb decay with sediment depth; use 210 The balance of Pb attenuation with sediment depth is used to measure the AMS of the modern sedimentary layer by taking the shallow surface layer of the sediment to be measured as the modern sedimentary layer. 14 C dating data; AMS for modern sedimentary horizons 14 C dating data and AMS 14 AMS of sediments obtained by C dating 14 C dating data are interpolated to obtain the correction value of "old carbon"; Except for the shallow surface layer of sediment to be measured, the AMS 14 The "old carbon" correction value is subtracted from the C dating data to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C calendar year value; Based on the AMS after correction of two adjacent layers in the sediment to be measured 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate; Determine the AMS of the sediment between two adjacent layers according to the deposition rate 14 C calendar year value; Determine the AMS of the sediments outside the adjacent two layers based on the sedimentation rate 14 C calendar year value; According to the AMS corrected for each layer of sediment to be measured 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
2. The sediment dating correction method according to claim 1, characterized in that: Adopting AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data, including: Obtaining sediment samples from each layer of the sediment to be tested, and converting acid-insoluble organic carbon in the sediment samples into graphite; The graphite is gasified, and carbon atoms in the gasified graphite are separated by an accelerator, and the separated carbon atoms are received by a Faraday cup at different positions of the accelerator track; the carbon atoms include 12 C. 13 C and 14 C; Based on the received separated carbon atoms 14 C / 12 The value of C or 14 C / 13 The value of C is to achieve 14 C measurement to obtain the AMS of each layer of the sediment to be tested 14 C dating data.
3. The sediment dating correction method according to claim 1, characterized in that: For the shallow surface of the sediment to be tested 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb attenuation with sediment depth includes: Take a set weight of the sediment to be tested, grind it and pass it through a 100-mesh sieve to obtain a sample powder; The sample powder is placed in a sample tube, sealed and placed for a set number of days; Use ORTEC high purity germanium well probe to probe into the sample tube containing the sample powder for radioisotope measurement and analysis 210 Pb decays exponentially with increasing depth according to the law of radioactive decay until 210 When the change in the value of Pb tends to be relatively stable, we get 210 The uniformity of Pb decay with sediment depth.
4. The sediment dating correction method according to claim 1, characterized in that: The AMS of the sediment between two adjacent layers is determined by interpolation based on the deposition rate. 14 C Calendar year value.
5. The sediment dating correction method according to claim 1, characterized in that: The AMS of sediments outside the two adjacent layers is determined by extrapolation from the deposition rate. 14 C Calendar year value.
6. A sediment dating correction system, characterized in that: The system is used to implement the sediment dating correction method according to any one of claims 1 to 5; the system comprises: The first dating module for the AMS 14 C dating method to obtain the AMS of each layer of the sediment to be tested 14 C dating data; The equilibrium determination module is used to determine the shallow surface layer of the sediment to be tested. 210 The isotope of Pb was tested and analyzed, and we obtained 210 The uniformity of Pb decay with sediment depth; The second dating module is used to 210 The uniformity of Pb attenuation with sediment depth is used to measure the AMS of the shallow surface of the sediment to be tested, taking the shallow surface of the sediment to be tested as the modern sedimentary layer. 14 C dating data; Correction value determination module for AMS of shallow sediment layers to be measured 14 C dating data and AMS 14 AMS of the shallow surface layer of the sediment to be tested obtained by C dating method 14 C dating data are interpolated to obtain the correction value of "old carbon"; The dating data correction module is used to correct the AMS data of other layers except the shallow surface layer of the sediment to be measured. 14 The "old carbon" correction value is subtracted from the C dating data to obtain the corrected AMS values for each layer of the sediment to be measured. 14 C calendar year value; Sedimentation rate determination module, used to determine the AMS based on the correction of two adjacent layers in the sediment to be measured 14 The calendar year value of C and the depth value between two adjacent layers determine the sedimentation rate; The third dating module is used to determine the AMS of the sediments between two adjacent layers according to the deposition rate. 14 C calendar year value; The fourth dating module is used to determine the AMS of sediments outside the adjacent two layers based on the deposition rate. 14 C calendar year value; Chronological framework building module for AMS calibrated according to the sediment layers to be measured 14 C calendar year value, AMS of sediments between two adjacent layers 14 C calendar year values and AMS of sediments outside the two adjacent layers 14 The C calendar year numerically constructs the chronological framework and completes the measurement of the age of the sediment to be measured.
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