Sediment dating correction method and system

Abstract

SOLUTION: The invention discloses a sediment dating correction method and system, and relates to the technical field of sediment age measurement. According to the method, the isotope characteristic of 210 Pb is utilized, the sediment horizon before 210 Pb is balanced is used as a modern substance (namely the modern sediment horizon), and the AMS14C dating data of the modern sediment horizon and the AMS14C dating data of the sediment to be measured obtained by adopting an AMS14C dating method are subjected to interpolation to obtain a corrected value of old carbon, so that all pieces of 14C dating data are corrected, and the age framework of the sediment to be measured is obtained (S100-S108).EFFECT: When a method is applied to the age correction of the 14C dating of the sediment lacking the perforated worms, the age of the sediment lacking the perforated worms can be accurately deduced, and the reliability and the accuracy of the 14C dating of the sediment are improved; in addition, the method is simple and easy to implement, extra equipment and complex experimental operation are not needed, and the cost and implementation difficulty of sediment age measurement are reduced.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the technical field of sediment dating, and particularly to a calibration method and system for sediment dating.

Background Art

[0002] Accurate age data is the basis and core for reconstructing past human activities, climate, and environmental changes. Radiocarbon dating of sediments 14 is a method widely used in geology and archaeology to determine the age of samples by measuring the content of the radioactive carbon isotope 14 14C in sediments. However, the current sediment 14 14C dating method mainly relies on the presence of foraminifera. In some specific environments such as mountain lakes, glaciers, deserts, etc., foraminifera are absent. For dating sediments lacking foraminifera, total carbon samples 14 14C are used, and due to the mixing of "old carbon", the dating results are too old, so accurate age calibration cannot be performed using the conventional 14 14C dating method.

Summary of the Invention

Problems to be Solved by the Invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a calibration method and system for sediment dating.

Means for Solving the Problems

[0004] To achieve the above object, the present invention provides the following solutions.

[0005] A calibration method for sediment dating, comprising: AMS 14 using the 14C dating method to obtain AMS 14 14C dating data for each layer of the sediment to be measured; and in the superficial layer of the sediment to be measured 210By testing and analyzing Pb isotopes, the balance of Pb attenuation according to the sediment depth is obtained, and 210 using the balance of Pb attenuation according to the sediment depth, the shallow surface layer of the sediment to be measured is taken as the modern sediment layer, and the AMS C dating data of the shallow surface layer of the sediment to be measured is measured, and 210 by interpolating the AMS 14 C dating data of the shallow surface layer of the sediment to be measured and the AMS C dating data of the shallow surface layer of the sediment to be measured obtained by the AMS 14 C dating method, the calibration value of "old carbon" is obtained, and 14 by subtracting the calibration value of the "old carbon" from the AMS 14 C dating data of other layers of the sediment to be measured except the shallow surface layer, the calibrated AMS C calendar year value of each layer of the sediment to be measured is obtained, and 14 based on the calibrated AMS 14 C calendar year values of two adjacent layers in the sediment to be measured and the depth values between the two adjacent layers, the sedimentation rate is determined, and based on the sedimentation rate, the AMS 14 C calendar year value of the sediment between two adjacent layers is determined, and based on the sedimentation rate, the AMS 14 C calendar year value of the sediment other than the two adjacent layers is determined, and based on the sedimentation rate, the AMS 14 C calendar year value of the sediment other than the two adjacent layers is determined, and based on the calibrated AMS 14 C calendar year values of each layer of the sediment to be measured, the AMS 14 C calendar year value of the sediment between two adjacent layers and the AMS 14 C calendar year values of the sediment other than the two adjacent layers, a chronological framework is constructed according to the corresponding values, and the dating of the sediment to be measured is completed, including.

[0006] Optionally, using the AMS 14 C dating method to obtain the AMS 14 C dating data of each layer of the sediment to be measured, specifically, Sediment samples are obtained from each layer of the sediment to be measured, and the acid-insoluble organic carbon in the sediment samples is converted to graphite, the graphite is gasified, the carbon atoms in the gasified graphite are separated through an accelerator, and a Faraday cup is used at various positions on the accelerator track to receive the separated carbon atoms, and the carbon atoms are 12 C, 13 C and 14 C are included, based on the received separated carbon atoms 14 C / 12 C value or 14 C / 13 C value is determined, 14 the measurement of C is realized, and the AMS 14 C dating data of each layer of the sediment to be measured are obtained. This includes

[0007] Optionally, by testing and analyzing the 210 Pb isotopes in the shallow surface layer of the sediment to be measured, the balance of the attenuation of 210 Pb with sediment depth is obtained. Specifically, a certain weight of the sediment to be measured is taken, pulverized, and passed through a 100-mesh sieve to obtain sample powder, the sample powder is put into a sample tube and left sealed for a certain number of days, using an ORTEC high-purity germanium well-type probe to probe the sample tube containing the sample powder for radioisotope measurement, 210 analyzing the law that 210 Pb decays exponentially as the depth increases according to the law of radioactive decay, 210 and obtaining the balance of the attenuation of

[0008] Optionally, based on the deposition rate by the interpolation method, the AMS 14 C calendar year value between two adjacent layers of sediment is determined.

[0009] Optionally, by the extrapolation method, based on the deposition rate, the AMS of sediments other than two adjacent layers14 Determine the C calendar year value.

[0010] Furthermore, the present invention also provides a calibration system for sediment dating used to implement the sediment dating calibration method provided above. The system includes AMS 14 A first dating module used to obtain AMS 14 C dating data for each layer of the sediment to be measured using the C dating method, and In the shallow surface layer of the sediment to be measured 210 A balance determination module used to obtain the balance of Pb decay according to the depth of the sediment by testing and analyzing the Pb isotopes in it, and 210 Using the balance of Pb decay according to the depth of the sediment, taking the shallow surface layer of the sediment to be measured as the modern sediment layer, a second dating module used to measure the AMS According to the depth of the sediment 210 C dating data, and a calibration value determination module used to obtain the calibration value of "old carbon" by interpolating the AMS 14 C dating data of the shallow surface layer of the sediment to be measured, and The AMS of the shallow surface layer of the sediment to be measured 14 C dating data and the AMS 14 C dating data of the shallow surface layer of the sediment to be measured obtained by the AMS 14 C dating method, and subtracting the calibration value of the "old carbon" from the AMS C dating data of other layers except the shallow surface layer of the sediment to be measured, a calibration module for dating data used to obtain the calibrated AMS 14 C calendar year value of each layer of the sediment to be measured, and 14 A sedimentation rate determination module used to determine the sedimentation rate based on the calibrated AMS C calendar year values of two adjacent layers in the sediment to be measured and the depth value between the two adjacent layers, and 14 A third dating module used to determine the AMS C calendar year value of the sediment between two adjacent layers based on the sedimentation rate, and 14 A third dating module used to determine the AMS The AMS of sediments other than two adjacent layers is based on the deposition rate 14 and a fourth dating module used to determine the calibrated AMS C calendar year value of each layer of the sediment to be measured, 14 the calibrated AMS 14 C calendar year value of the sediment between two adjacent layers, and the AMS 14 C calendar year value of sediments other than two adjacent layers, and a chronology construction module used to construct a chronology according to the AMS

Advantages of the Invention

[0011] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects. 1. When the calibration method for sediment dating provided by the present invention is applied to the age calibration of sediment C dating without foraminifera, the gap in the prior art can be filled. 14 2. By analyzing the total carbon C dating data and 14 Pb isotope data of the sediment, the present invention can accurately estimate the age of the sediment lacking foraminifera and improve the 210 reliability and accuracy of sediment 14 C dating. 3. The present invention is simple and easy to implement, does not require additional equipment or complex experimental operations, and reduces the cost and difficulty of sediment dating.

Brief Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the drawings that need to be used in the following embodiments will be briefly described. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0013]

Figure 1

Best Mode for Carrying Out the Invention

[0014] Next, while referring to the drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts are included within the protection scope of the present invention.

[0015] The present invention can accurately estimate the age of sediments lacking foraminifera, improve the reliability and accuracy of 14C dating of sediments, and reduce the cost and difficulty of sediment age measurement because it does not require additional equipment or complex experimental operations. An object of the present invention is to provide a calibration method and system for age measurement suitable for sediments lacking foraminifera. 14 C dating reliability and accuracy, and can reduce the cost and difficulty of sediment age measurement because it does not require additional equipment or complex experimental operations. An object of the present invention is to provide a calibration method and system for age measurement suitable for sediments lacking foraminifera.

[0016] To make the above objects, features, and advantages of the present invention more prominent and understandable, the present invention will be described in more detail below with reference to the drawings and the best mode for carrying out the invention.

[0017] The present invention utilizes the "substitution" principle of TRIZ and analyzes the total carbon sample of the sediment and the isotope content of 210Pb to replace the traditional sediment 14C dating method that depends on foraminifera. This alternative is creative and can solve the problem that conventional methods cannot accurately measure the age of sediments lacking foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between the isotope content and the age, and uses an interpolation calculation method to realize accurate age calibration of the sediment to be measured. 210 Pb isotope content to replace the traditional sediment 14C dating method that depends on foraminifera. This alternative is creative and can solve the problem that conventional methods cannot accurately measure the age of sediments lacking foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between the isotope content and the age, and uses an interpolation calculation method to realize accurate age calibration of the sediment to be measured. 14 C dating method that depends on foraminifera. This alternative is creative and can solve the problem that conventional methods cannot accurately measure the age of sediments lacking foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between the isotope content and the age, and uses an interpolation calculation method to realize accurate age calibration of the sediment to be measured.

[0018] As shown in FIG. 1, the sediment age measurement method provided by the present invention includes the following. Step 100: Use the AMS 14C dating method to obtain the AMS 14C dating data of each layer of the sediment to be measured. 14 C dating method to obtain the AMS 14C dating data of each layer of the sediment to be measured. 14 C dating data of each layer of the sediment to be measured. In actual applications, AMS 14 C dating experiments are carried out on the total carbon of columnar sediments to obtain the AMS 14 C dating data for each layer of the sediment to be measured. Specifically, First, the acid-insoluble organic carbon in the sediment sample is converted to graphite, then the graphite is gasified, passed through an accelerator, and through steps such as removal of impurity particles, stripping of electrons, and acceleration of positrons, 12 C, 13 C, 14 C carbon atoms are separated. Finally, Faraday cups are used to receive the carbon atoms at various locations on the accelerator track, and then 14 for measuring 14 C / 12 C values or 14 C / 13 C values are calculated to obtain the AMS 14 C dating data of the sediment to be measured.

[0019] Step 101: By testing and analyzing 210 Pb isotopes in the shallow surface layer of the sediment to be measured, the balance of 210 Pb decay with sediment depth is obtained. In actual applications, through experiments, 210 Pb isotope testing and analysis in the shallow surface layer of columnar sediments are carried out to obtain the balance of 210 Pb decay with sediment depth. The experiment is carried out in accordance with the national standard of the People's Republic of China, "Measurement of Radionuclides in Marine Sediments - Gamma-ray Energy Spectrometry (GB / T 30738-2014)". Specifically, Approximately a certain weight (e.g., 10 g) of dry sediment is pulverized, passed through a 100-mesh sieve to remove plant roots and rhizomes, placed in a sample tube and sealed, and left for a certain number of days (e.g., 20 days). Next, radioisotope measurements are carried out using an ORTEC high-purity germanium well-type probe (GWL-120-15N). The measurement time for each sample is usually 1 to 3 days, and the total 210 Pb specific radioactivity is the peak area at an energy of 46.5 keV ( 210 Pb), and the background 210The specific radioactivity of Pb is 351 keV ( 214 Pb, 226 the daughter of Ra) and is calculated from the peak area at this energy. The specific radioactivity of excess 210 Pb is the difference between the total specific radioactivity of 210 Pb and the background 210 specific radioactivity of Pb. 210 Analyze the law by which Pb decays exponentially as the depth increases according to the law of radioactive decay. Among them, 210 Pb belongs to the uranium series decay nuclides, its half-life is 22.3 a, and the intensity of the 210 Pb nuclide, which is commonly used in sediment dating, decays to about 1% of the initial value after about 7 half-lives, making it difficult to accurately detect with equipment. 210 Therefore, the upper limit of 210 Pb dating is about 150 a. The total uranium series decay nuclides in sediments 226 Pb is composed of two parts. One part is 210 Pb derived from the natural decay of 210 Ra accumulated in sediments and is called compensated 210 Pb. The other part is derived from precipitated 210 Pb and is called excess 210 Pb or ex Pb. 226 Both 210 Ra and 238 Pb belong to the 226 U decay series nuclides, and 210 Ra and 226 Pb can be regarded as a pair of parent and daughter. 210 Assuming that there are no other inputs and outputs for 210 Ra and

[0020] Step 102: Using the balance of the decay of 210 Pb with sediment depth, measure the AMS 14 C dating data of the superficial layer of the sediment to be measured as the modern sediment layer. Step 103: AMS of the superficial layer of the sediment to be measured 14 C dating data and AMS 14 AMS of the superficial layer of the sediment to be measured obtained by the AMS 14 C dating method to obtain the calibration value of "old carbon" by interpolating the AMS Step 104: AMS of other layer positions other than the superficial layer of the sediment to be measured 14 Subtract the calibration value of "old carbon" from the AMS 14 C dating data to obtain the calibrated AMS of each layer of the sediment to be measured

[0021] From Step 102 to Step 104, the superficial layer sediment according to the depth in Step 101 210 Use the balance of Pb decay to determine the modern sediment layer (0 cal BP) and its AMS 14 C dating data, and measure the AMS 14 C dating data measured in Step 100 and Step 102 to interpolate the calibration value of "old carbon", and for the AMS of other layer positions 14 Subtract the calibration value of the "old carbon" from the C value to achieve calibration, and further obtain the calibrated AMS of each layer of the sediment to be measured 14 C calendar year value

[0022] Step 105: Calibrated AMS of two adjacent layers in the sediment to be measured 14 Determine the deposition rate based on the calibrated AMS C calendar year value and the depth value between two adjacent layers 14 Step 106: Based on the deposition rate, determine the AMS of the sediment between two adjacent layers 14 C calendar year value. Among them, according to the deposition rate, for the part between the two layer positions, the corresponding AMS C calendar year value is calculated by interpolation 14 Step 107: Based on the deposition rate, determine the AMS of the sediment other than the two adjacent layers 14 C calendar year value. Among them, in order to establish the subsequent time frame, extrapolation is performed for those other than the two layer positions, and the corresponding AMS Step 108: Calibrated AMS of each layer of the sediment to be measured 14 C calendar year value, AMS of sediment between two adjacent layers 14 C calendar year value and AMS of sediment other than two adjacent layers 14 Construct a chronological framework according to the C calendar year value to complete the dating of the sediment to be measured.

[0023] Based on the above description, the present invention 210 Based on the fact that Pb widely exists in the natural environment and has a half-life of 22.3 a, the previously formed 210 Pb decays exponentially with increasing depth according to the law of radioactive decay, reaches equilibrium at a certain depth, and it is considered that the sediment above that depth is within 150 a. Compared with the half-life of 5730 a for 14 C dating and the error of decades to hundreds of years 210 The sediment layer before Pb reaches equilibrium can be regarded as modern material, and since the age value is set as 0 Cal a BP, the 14 C measurement value is determined as the error value of "old carbon", and all 14 C dating data at this observation point are calibrated to establish a chronological framework of calendar years.

[0024] Based on this, the present invention utilizes the "substitution" principle of TRIZ to analyze the total carbon sample of the sediment and 210 the isotope content of Pb, thereby replacing the traditional sediment 14 C dating method that relies on foraminifera. This alternative can solve the problem that the conventional method cannot accurately date the sediment lacking foraminifera. At the same time, the present invention also combines the "interpolation" principle, establishes a relationship model between the isotope content and the age, and uses the interpolation calculation method to realize the accurate age calibration of the sample to be measured.

[0025] Furthermore, the present invention also provides a calibration system for sediment dating used to implement the sediment dating calibration method provided above. The system includes a first dating module, a balance determination module, a second dating module, a calibration value determination module, a dating data calibration module, a sedimentation rate determination module, a third dating module, a fourth dating module, and a chronology framework construction module.

[0026] The first dating module uses the AMS 14 14C dating method to obtain the AMS 14 14C dating data for each layer of the sediment to be measured.

[0027] The balance determination module is used to obtain the balance of Pb decay with sediment depth by testing and analyzing the Pb isotopes in the superficial layer of the sediment to be measured. 210 Pb isotopes in the superficial layer of the sediment to be measured are tested and analyzed to obtain the balance of Pb decay with sediment depth. 210 It is used to obtain the balance of Pb decay with sediment depth by testing and analyzing the Pb isotopes in the superficial layer of the sediment to be measured.

[0028] The second dating module uses the balance of Pb decay with sediment depth to measure the AMS 210 14C dating data of the superficial layer of the sediment to be measured, taking the superficial layer of the sediment to be measured as the modern sediment layer. 14 It is used to measure the AMS

[0029] The calibration value determination module is used to obtain the calibration value of "old carbon" by interpolating the AMS 14 14C dating data of the superficial layer of the sediment to be measured and the AMS 14 14C dating data of the superficial layer of the sediment to be measured obtained by the AMS 14 14C dating method.

[0030] The dating data calibration module subtracts the calibration value of "old carbon" from the AMS 14 14C dating data of other layers except the superficial layer of the sediment to be measured, and is used to obtain the calibrated AMS 14 14C calendar year value for each layer of the sediment to be measured.

[0031] The deposition rate determination module is used to determine the deposition rate based on the calibrated AMS 14 calender year values of two adjacent layers in the sediment to be measured and the depth values between the two adjacent layers.

[0032] The third dating module is used to determine the AMS 14 calender year value of the sediment between two adjacent layers based on the deposition rate.

[0033] The fourth dating module is used to determine the AMS 14 calender year value of the sediment other than that between two adjacent layers based on the deposition rate.

[0034] The age frame construction module constructs an age frame according to the calibrated AMS 14 calender year values of each layer of the sediment to be measured, the AMS 14 calender year values of the sediment between two adjacent layers, and the AMS 14 calender year values of the sediment other than that between two adjacent layers, and is used to complete the dating of the sediment to be measured.

[0035] Each embodiment in this specification is described step by step. What each embodiment mainly describes are all the differences from other embodiments. For the same or similar parts between each embodiment, reference may be made 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 information may be referred to the description of the method part.

[0036] In this specification, specific examples are used to explain the principles and embodiments of the present invention. The description of the above embodiments is only used to understand the method and the central idea of the present invention. At the same time, for those skilled in the art, based on the idea of the present invention, there are changes in the forms and application scopes for implementing the invention. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. 1. A method for calibrating sediment dating, comprising: AMS １４ Using the C dating method, AMS was performed on each layer of the measured sediment. １４ Obtaining C dating data; and Located in the shallow surface layer of the measured sediment ２１０ By testing and analyzing Pb isotopes, it was possible to determine the ２１０ To obtain a balance of Pb decay; Depends on the depth of the deposits ２１０ Taking advantage of the equilibrium of Pb attenuation, the shallow surface layer of the measured deposits was taken as the modern sedimentary horizon, and the AMS of the modern sedimentary horizon was used. １４ Measuring C dating data; AMS of modern sedimentary horizons １４ C dating data and AMS １４ AMS of the measured sediments obtained by the C dating method １４ Obtaining a calibration value for "old carbon" by interpolating C dating data; AMS of strata other than the shallow surface layer of the measured sediment １４ The "old carbon" calibration value was subtracted from the C dating data, and the calibrated AMS for each layer of the measured sediment was １４ Obtaining a calendar year value of C; AMS after calibration of two adjacent layers in the measured deposit １４ determining a deposition rate based on the C calendar value and a depth value between two adjacent layers; Based on the deposition rate, the AMS of the deposit between two adjacent layers is １４ determining a calendar year value of C; Based on the deposition rate, the AMS of the deposit other than the two adjacent layers is １４ determining a calendar year value of C; AMS after calibration for each layer of the measured deposit １４ C calendar year value, AMS of the deposit between two adjacent layers １４ C calendar year values ​​and AMS of sediments other than the two adjacent layers １４ and constructing a time frame according to the C calendar value and completing the dating of the measured sediments.

2. AMS １４ Using the C dating method, AMS was performed on each layer of the measured sediment. １４ Specifically, obtaining C dating data involves: obtaining a sediment sample from each layer of the sediment to be measured, and converting acid-insoluble organic carbon in the sediment sample to graphite; The graphite is gasified, and carbon atoms in the gasified graphite are separated through an accelerator. A Faraday cup is used at various positions in the accelerator orbit to receive the separated carbon atoms, and the carbon atoms are １２ C. １３ C and １４ containing C; Based on the carbon atoms received after separation １４ C / １２ C value or １４ C / １３ Determine the C value, １４ C measurement and AMS of each layer of the measured deposit. １４ and acquiring C dating data.

3. Located in the shallow surface layer of the measured sediment ２１０ By testing and analyzing Pb isotopes, it was possible to determine the ２１０ To obtain a balanced decay of Pb, specifically, Taking a certain weight of the sediment to be measured, crushing it, and passing it through a 100 mesh sieve to obtain a sample powder; Put the sample powder into a sample tube, seal it, and leave it for a certain number of days. Using an ORTEC high-purity germanium well-type probe, a sample tube containing sample powder is probed to perform radioisotope measurements. ２１０ Analyzing the law of Pb exponentially decaying with depth according to the law of radioactive decay, ２１０ The change in Pb value with the depth of the deposits continues until it becomes relatively stable. ２１０ and obtaining a balance of Pb decay.

4. Based on the deposition rate by interpolation, the AMS of the deposit between two adjacent layers is calculated. １４ 2. The method of claim 1 for calibrating sediment dating, further comprising determining a C calendar year value.

5. Based on the deposition rate, the AMS of the deposit other than the two adjacent layers is calculated by extrapolation. １４ 2. The method of claim 1 for calibrating sediment dating, further comprising determining a C calendar year value.

6. A sediment dating calibration system, the system being used to implement the sediment dating calibration method according to any one of claims 1 to 5, the system comprising: AMS １４ Using the C dating method, AMS was performed on each layer of the measured sediment. １４ a first dating module used to obtain C dating data; and Located in the shallow surface layer of the measured sediment ２１０ By testing and analyzing Pb isotopes, it is possible to determine the ２１０ a balance determination module used to obtain the balance of the decay of Pb; Depends on the depth of the deposits ２１０ Taking advantage of the equilibrium of Pb attenuation, the shallow surface layer of the measured deposits was regarded as the modern sedimentary horizon, and the AMS of the shallow surface layer of the measured deposits was used. １４ a second dating module used to measure the C dating data; and AMS of the shallow surface layer of the measured deposit １４ C dating data and AMS １４ AMS of the shallow surface layer of the measured sediments obtained by C dating method １４ a calibration value determination module used to obtain an "old carbon" calibration value by interpolating the C dating data; AMS of strata other than the shallow surface layer of the measured sediment １４ The "old carbon" calibration value was subtracted from the C dating data, and the calibrated AMS for each layer of the measured sediment was １４ a dating data calibration module used to obtain the C calendar year value; AMS after calibration of two adjacent layers in the measured deposit １４ a deposition rate determination module used to determine a deposition rate based on the C calendar value and the depth value between two adjacent layers; Based on the deposition rate, the AMS of the deposit between two adjacent layers is １４ a third dating module used to determine the C calendar year value; Based on the deposition rate, the AMS of the deposit other than the two adjacent layers is １４ a quaternary dating module used to determine the C calendar year value; and AMS after calibration for each layer of the measured deposit １４ C calendar year value, AMS of the deposit between two adjacent layers １４ C calendar year values ​​and AMS of sediments other than the two adjacent layers １４ and a date frame construction module that is used to construct a date frame according to the C calendar year value and complete the dating of the measured sediment.

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