Energy and Earth Science Vol. 7, No. 1, 2024 www.scholink.org/ojs/index.php/ees ISSN 2578-1359 (Print) ISSN 2578-1367 (Online) 1 Original Paper A Cheap New Geological Dating Method Developed from Ancient Shells Study Chen Guiqing 1 & Chen Junhao 1 1 Guangzhou Jinan University 510630, Guangzhou, China Received: November 25, 2023 Accepted: December 7, 2023 Online Published: March 25, 2024 doi:10.22158/ees.v7n1p1 URL: http://dx.doi.org/10.22158/ees.v7n1p1 Abstract The vast majority of researchers on ancient shells are biologists, who are not familiar with X-ray diffractometers, etc. We are physical chemists who use X-ray diffraction to observe the changes in the crystal structure of ancient shells? Then use WDX electron probe to observe the changes in the microstructure of ancient shells. After discovering shells for a long time, calcite turned into aragonite, overturning the conclusion recorded in geological crystallographic books that aragonite’s structure and physical properties were unstable and would eventually transform into calcite. Unexpectedly discovered that the “Shuang chen Weathering Cave CC” of ancient shells has changed over time, it can be used as a new method for geological dating. The use of carbon 14 (C14) isotope geological dating method is quite expensive and lacks accuracy, causing many jokes. The “Shuang chen Weathering Cave CC” of ancient shells may be used as a new geological dating method, and it is quite cheap! Keywords marine biology, aragonite structure, calcite structure, D/max-1-A type X-ray diffractometer, WDX electron probe, CC- double Chen weathering cave www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 2 Published by SCHOLINK INC. Introduction Authoritative textbooks in China: Zhang Xi and Qi Zhongyan’s “Outline of Shellfish Studies” believe that the structure of shells can generally be divided into three layers, with the outermost layer called the stratum corneum, which is only composed of shell elements. The middle layer is a prism layer, which occupies the majority of the shell and is composed of angular columnar calcite (ca1cite). The inner layer is usually composed of leaf shaped aragonite, known as the pearl layer, which is glossy, and pearls are formed from the nacreous layer. This theory has been widely cited and has been read by almost all biology students in China. In the 1980s, we used X-ray diffraction to prove that the conclusion that the shell prism layer is a calcite structure was completely incorrect, which may have been copied from the Japanese. However, shellfish expert Master Hu observed under a microscope and believed that it was still a calcite structure. Oh my goodness! In the 1920s, shellfish scientists still don’t know that crystal structure can only be determined by X-ray diffraction. The German physicist Roentgen discovered X-rays on November 8, 1895! In the 1980s, Huang Baoyu, a researcher at the Nanjing Institute of Paleontology, provided ancient shells: Schistodesmus sp., Schistodesmus lampreyanus (Baird & Adams), Unio douglasiae Griffith et Pidgeon, and Lamprotula hazinic (Heude). We use the electron microprobe from the South China Sea Institute of Oceanography, Chinese Academy of Sciences! Recently, the Corbicula maxima Prime shell was borrowed from Tan Yehui, a researcher at the Chinese Academy of Sciences Guangzhou South China Sea Institute of Oceanography, and Dr. Chen Zhiyun, and excavated from the Longyan Village Water Conservancy Project in Shunde, Guangdong. Collectors: Zhao Huanting et al. Collection time: February 1961. Era: 500 to 1000 years ago. Measurement date/time: 2015-11-27 9:48:41. Using the Empyrean X-ray diffractometer from Sun Yat Sen University. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 3 Published by SCHOLINK INC. The first part Comparison of X-ray diffraction lines between modern and ancient shells Grind each layer of the shell into powder using an agate mortar and pass it through a 360 mesh sieve. Using D/max-1-A X-ray diffractometer and Cu target KαX-ray diffraction, under 40kV, 50mA conditions, within 30 minutes from 2θ Range 20 0 -80 0 , instrument uses a Plot plotter and automatically prints 2θ, Absolute strength I and corresponding crystal plane group spacing d. Refer the above results to the international universal phase analysis (JCPDS) card to determine the crystal structure of the sample. d=0.3399nm, and the horizontal bars at the bottom of the spectral lines are all aragonite structured spectral lines. 1. X-ray Diffraction Results Table 1. X-ray Diffraction Data of Modern and Ancient Shells Modern Cristaria plicata(Leach) Shell Powder Corbicula maxima pearl layer Corbicula maxima prismatic layer Corbicula maxima periostracum layer d( nm) I/I0 % d (nm) I/I0 % d(nm) I/I0 % d( nm) I/I0 % 0.3399 99.99 0.2875 100.00 0.3407 5.31 0.3399 90.81 0.3276 51.05 0.2706 58.06 0.3287 2.61 0.3279 54.75 0.2875 11.22 0.1862 1.48 0.2879 10.97 0.2703 54.46 0.2705 79.03 0.1744 2.09 0.2709 100.00 0.2484 46.31 0.2487 41.80 0.1438 5.77 0.2492 16.96 0.2413 20.54 0.2412 16.49 0.1415 32.81 0.2378 27.43 0.2377 56.42 0.2376 53.68 0.1361 3.21 0.2334 13.13 0.2345 36.76 0.2342 37.09 0.1979 1.33 0.2193 16.07 0.2333 33.62 0.1881 1.45 0.2110 28.15 0.2192 14.26 0.1817 2.48 0.1980 100.00 0.2108 31.65 0.1747 42.95 0.1883 50.92 0.1980 100.00 0.1729 21.7 0.1819 41.6 0.1883 47.76 0.1746 46.3 0.1817 37.27 0.1761 5.95 0.1745 50.73 0.1728 30.45 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 4 Published by SCHOLINK INC. Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 1000 2000 3000 4000 SCSMBC007426 NC Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 1000 2000 3000 SCSMBC007426 ZC Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 200 400 600 800 SCSMBC007426 WC X-ray diffraction pattern: Figure 1 Modern Cristaria plicata (Leach) Shell Powder. Figure 2 Corbicula maxima pearl layer. Figure 3 Corbicula maxima prismatic layer. Figure 4 Corbicula maxima periostracum layer. 2. Discussion of Results 2.1 The crystal structure of ancient shells is the same as that of modern shells. The prismatic layer is all aragonite structure, which overturns the conclusion of “shellfish outline”. 2.2 The X-ray diffraction pattern of the pearl layer in the Corbicula maxim shell appears very special, with the absolute intensity of the strongest spectral line d=0.2875nm reaching I=4290.7 (the maximum intensity of the spectral line in a typical shell is about 700). The spectral lines are very strong, narrow, and few, all of which are thick aragonite grains with obvious “monocrystallization” and no impurity spectral lines. Unlike geological crystallography think, where the structure of aragonite is unstable, it will eventually become calcite. But rather development towards a higher degree of single crystal indicates that the structure of aragonite is stable. According to the Scherrer formula of X-ray diffraction theory of crystals, the strengthening, narrowing, and decreasing of spectral lines are caused by the growth and thickening of grains in this diffraction direction (preferential orientation growth), which we refer to as the “single crystal tendency”. The growth process of seashells is the growth process of aragonite crystals, constantly in an unbalanced state. Due to vacancies or impurities filling the lattice, the lattice distortion changes the spacing between crystal planes and broadens the spectral lines, resulting in new internal stresses. After the death of shellfish, crystal growth stops and no new internal stress is generated. The stress inside the shell gradually releases, vacancies are gradually filled or impurities are gradually eliminated to the www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 5 Published by SCHOLINK INC. grain boundary to eliminate internal stress. At this time, internal stress is also concentrated at the grain boundary, so this area is prone to weathering. The grains of aragonite continue to grow, therefore; Make the spectral lines stronger, narrower, and fewer! Due to the Corbicula maxima shell, it is less affected by the surrounding soil, which better reflects this process. 2.3 The X-ray diffraction pattern of the prismatic layer of the Corbicula maxim shell is similar to that of the pearl layer, with strong, narrow, and few spectral lines. All spectral lines are thick aragonite grains with a “single crystal tendency”, and there are no impurity spectral lines. The absolute intensity of the strongest spectral line d=0.2709nm reaches I=3406.33, which is very strong, narrow, and has very few spectral lines! But because the prism layer is located in the middle of the shell, between the nacre layer and the stratum corneum, the internal stress release is slower, so the spectral lines are slightly more than the nacre layer. It is exactly the same as the pearl layer. From its X-ray diffraction pattern, it appears that many weak spectral lines have become almost flattened and are developing towards a “monocrystalline trend”, similar to the pearl layer above, without impurity spectral lines. 2.4 X-ray diffraction pattern of periostracum layer of the Corbicula maxim shell. Due to the influence of the epidermis, the spectral lines become more numerous and wider. But all spectral lines are of aragonite structure and have no impurity spectral lines. 2.5 It can be seen from the table that there are more spectral lines in the shell of modern pleated clamshell than that of ancient clam shell. Especially from the spectrum diagram is clear at a glance. The aragonite structure of the ancient shell continues to grow, with obvious “monocrystalline”, excluding impurities. Modern shells contain some calcite, but ancient shells contain almost no calcite. It shows that after a long age of shells, calcite becomes aragonite! www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 6 Published by SCHOLINK INC. The second part Electron Microprobe experiment of four kinds of ancient shells 1. Materials and Methods In the 1980s, researcher Huang Baoyu from the Nanjing Institute of Paleontology provided us with four types of ancient shells and explored them using the Electron Microprobe from the South China Sea Institute of Oceanography, Chinese Academy of Sciences! 2. Experimental Results 2.1 Schistodesmus sp.shell. 102 points, Ding Village, Xiangfen, Shanxi, with field number ADY201 1983/9/9. Era: hundreds to thousands of years. Elements with atomic numbers below 11 (Na) cannot be measured, therefore; CaCO3 can only be calculated from the CaO molecular formula. The results are shown in Table 1. CaO+CO2--→CaCO3 MCaCO3=(100.089÷56.0794)×MCaO=1.784777×M CaO. 56.0794 100.0892 Inner layer MCaCO3=1.78478×48.165=85.964; Surface MCaCO3=1.78478×45.125=80.538. The same applies below. Total in the table Ʃ The sum of calcium carbonate and other oxides. Sum of electron probe measurements of modern shells Ʃ. They are all around 100%, which is caused by errors caused by certain factors and can be normalized to 100%. However, the results of ancient shells are at a certain distance from 100%. This is the result of ancient shells weathering for thousands of years, and we define it as the “Shuang Chen Weathering Cave”: CC=100-Ʃ. The various parts of ancient shells are different, and the average value CC ------- is taken to represent them. According to the dozens of modern shells we tested, the general result is 98.5<Ʃ. Therefore, it is assumed that CC values below 2 can be ignored and considered as 0, indicating that there is no “Shuang Chen Weathering Cave”. Because the range of electron probe testing is very small, important data needs to be measured at several points to obtain the average value, the same below. 2.2 Schistodesmus lampreyanus (Baird & Adams) shell 102 points, Ding Village, Xiangfen, Shanxi, 1986/12/16. Era: hundreds to thousands of years. The results are shown in Table 2. 2.3 Unio douglasiae Griffith et Pidgeon shell. No.102, Dingcun, Xiangfen, Shanxi, with field number ADY201 1986/12/16. Era: hundreds to thousands of years. The results are shown in Table 3. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 7 Published by SCHOLINK INC. 2.4 Lamprotula hazinic (Heude) shell. 102 points in Ding Village, Xiangfen, Shanxi, with field number ADY193 1986/12/16. Era: hundreds to thousands of years. The results are shown in Table 4. 2.5 Modern Pinctada Martensi (Dunker) pearl shell. The results are shown in Table 5. 2.6 Modern Lamprotula mansuyi (Dautzenberg et Fischer) shell. The results are shown in Table 6. 2.7 Modern Mactra Antiquata Spengler shell. The results are shown in Table 7. 2.8 Modern Arca (Anadara) granosa Linnaeus shell. The results are shown in Table 8. Table 1-8. Oxide of Shell Oxide Na2O K2O Fe2O3 MnO SiO2 MgO TiO2 Al2O3 CaO CaCO 3 Ʃ CC CC ------- Table 1 Ancient Schistodesmus sp. Inner layer 0.254 0.000 0.000 0.028 0.058 0.040 0.045 0.066 48.165 85.964 86.455 13.54 15.9 Table 2 Ancient Schistodesmus lampreyanus Inner layer 0.151 0.005 0.000 0.000 0.044 0.034 0.000 0.040 43.156 77.024 77.298 22.70 19.9 Surface layer 0.168 0.008 0.046 0.028 0.103 1.227 0.000 0.046 45.512 81.229 82.855 17.14 Surface layer 0.188 0.024 0.092 0.000 0.571 0.146 0.022 0.142 45.125 80.538 81.723 18.28 Table 3 Ancient Unio douglasiae Inner layer 0.113 0.026 0.031 0.042 0.029 0.046 0.000 0.061 45.758 81.668 82.016 17.98 19.3 Surface layer 0.104 0.000 0.015 0.028 0.073 0.012 0.000 0.030 44.361 79.175 79.437 20.56 Table 4 Ancient Lamprotula sp. Inner layer 0.254 0.000 0.092 0.042 0.029 0.000 0.046 46.730 83.403 83.901 83.901 16.10 12.8 Surface layer 0.217 0.005 0.230 0.000 0.059 0.000 0.086 50.298 89.771 90.415 90.415 9.58 Table 5 Modern Pinctada fucata martensi Pearl layer 0.516 0.007 0.020 0.018 0.038 0.058 0 0.030 55.644 99.313 100.00 0 0 0 Prismatic layer 0.429 0.023 0.039 0.000 0.000 0.085 0 0.065 55.670 99.360 100.00 0 0 Periostracum 0.282 0.039 0.000 0.000 0.019 1.205 0 0.048 55.137 98.409 100.00 0 0 Table 6 Modern Lamprotula mansuyi Pearl layer 0.38 0.03 0.08 0.07 0.37 0.06 0 0.11 55.65 99.323 100.42 3 0 0 Prismatic layer 0.59 0.09 0.06 0.11 0.43 0.05 0 0.12 55.67 99.359 100.80 9 0 Periostracum 0.25 0.00 0.00 0.04 0.42 0.03 0 0.08 55.38 98.841 99.661 0 Table 7 Modern Coelomactra antiquate A region 0.62 0.02 0.03 0.00 0.02 0.04 0 0.05 55.59 99.216 99.996 0 0 B region 0.60 0.03 0.00 0.02 0.03 0.00 0 0.00 55.65 99.323 100.00 3 0 Table 8 Modern Tegillarca granosa A region 0.56 0.01 0.00 0.04 0.03 0.07 0 0.03 55.61 99.252 99.992 0 0 B region 0.53 0.01 0.00 0.00 0.00 0.07 0 0.03 55.67 99.360 100.00 0 0 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 8 Published by SCHOLINK INC. Table 9. Comparison of the “Double Chen Weathered Hole CC” Result between Ancient and Modern Shells Ancient shell species Oxide summation Ʃ — Double Chen weathered hole CC ------- Moder shell species Oxide summation Ʃ — Double Chen weathered hole CC ------- Schistodesmus sp. 84.09 15.9 Pinctada martensi shell 100.00 0 Schistodesmus lampreyanus 80.08 19.9 Lamprotula mansuy shell 100.30 0 Unio douglasiae 80.73 19.3 Mactra antiquate shell 100.00 0 Lamprotula sp. 87.16 12.8 Arca (Anadara) granosa shell 100.00 0 3. Result Discussion 3.1 We studied the electron probe Electron Microprobe detection of 8 samples from 4 ancient and 4 modern shells. As a result, many voids were found in the ancient shell-“Shuang chen Weathering Cave CC” as shown in Table 9! We hope it can become a cheap method for dating ancient artifacts! 3.2 In order to achieve the purpose of this article, we sincerely hope that relevant researchers can conduct further research! Funding 90 year old commemorative works IV Fund project “Artificial growth of aragonite crystals and artificial development of pearls” Chen Guiqing, Chen Junhao 1985 (Approval No. 85084). Fund project “Research on the Structure and Imaging Mechanism of Artificial Pearl Cores and Artistic Pearl Images” Chen Guiqing, Chen Junhao. 1989 (Approval number 38870643). References Cao, B. X. (2014). AMS carbon C14 dating method and analysis. Baidu Wenku-Education-Higher Education-Science. Chen, G. Q., & Chen, J. H. (1988). A study on the crystal structure types of seashells. Chinese Marine Medicine, 1988(1-2), 21-29. https://doi.org/10.2753/CED1061-1932210129 Chen, G. Q., & Chen, J. H. (2017). New Conclusion on the Crystal Structure of Pearls and Shells. Journal of Applied Oceanography, 36(4). Chen, G. Q., Chen, J. H., & Chen, P. (1987). A study on the natural pearls and shells of Pinctada martensii. 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