From Triassic to moderinity: Raman spectroscopy for differentiation of fossil resins age by age

The results of studies of fossil resins of different geological ages and geographic origins are presented. A new method of spectral analysis for differentiation of fossil resins by age from the Triassic period to Modernity is developed. Raman spectra of fossil resin of the late Triassic period are obtained for the first time. The possibility of using the method for differentiation of resin from the late Triassic period to the Moderiny is shown. The studies were carried out using Raman spectroscopy. The spectra were obtained using a Renishaw Virsa spectrometer (UK) with an excitation wavelength of 785 nm and a Raport 1064 portable Raman spectrometer (Russia) with an excitation wavelength of 1064 nm. The range of the studied spectra was 400–3200 cm^–1. 27 samples of fossil resins from Eurasia, Africa, America, and Australia were studied. Based on the results of studies of fossil resin samples from different geographic locations and ages, differences were found in the values of the ratio of vibrational modes of the valence skeletal vibrations (ν(C=C)) and the deformation vibration of the CH2 bond (σ(CH₂)) in the wavenumber ranges of 1650–1600 cm^–1 and 1440–1460 cm^–1 in fossil resins aged from late Triassic to Modernity. It was found that with increasing age of amber, the degree of their polymerization decreases. For amber of age Triassic, the absence of ν(CH₂,CH₃) signals in the high-frequency region for the labdanum skeleton of the resin structure was shown, which indicates an extremely low degree of polymerization of it structure. The obtained results potentially allow using the Raman scattering method for additional differentiation of the age of fossil resins, in case of limitation of the application of the radiocarbon analysis method by age (40,000 years). The advantage of the proposed method is the possibility of rapid, with minimal sample preparation, determination of the age of fossil resin of ages Triassic, Cretaceous, Modernity. At the same time, the accuracy of differentiation of the ages of fossil resins in the age range from Cretaceous to Oligocene to Middle Miocene still remains low, which requires additional research. Also, at the current stage of development, the method does not take into account the influence of environmental conditions: climate, fossilization conditions under which the oleoresin was transformed into resin.

1. Truică G., Teodor E., Litescu S., Radu G. LC-MS and FT-IR characterization of amber artifacts. Open Chemistry, 2012, vol. 10, no. 6, pp. 1882–1889. https://doi.org/10.2478/s11532-012-0103-5

2. Xing Q.Y., Yang M., Yang H.X., Zu E.D. Study on the gemological characteristics of amber from Myanmar and Chinese Fushun. Key Engineering Materials, 2013, vol. 544, pp. 172–177. https://doi.org/10.4028/www.scientific.net/kem.544.172

3. Chen D., Zeng Q., Yuan Y., Cui B., Luo W. Baltic amber or Burmese amber: FTIR studies on amber artifacts of Eastern Han Dynasty unearthed from Nanyang. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2019, vol. 222, pp. 117270. https://doi.org/10.1016/j.saa.2019.117270

4. Broughton P.L. Conceptual frameworks for geographic-botanical affinities of fossil resins. Canadian Journal of Earth Sciences, 1974, vol. 11, no. 4, pp. 583–594. https://doi.org/10.1139/e74-053

5. Cunningham A., Gay I.D., Oehlschlager A.C., Langenheim J.H. 13C NMR and IR analyses of structure, aging and botanical origin of Dominican and Mexican ambers. Phytochemistry, 1983, vol. 22, no. 4, pp. 965–968. https://doi.org/10.1016/0031-9422(83)85031-6

6. Langenheim J.H., Beck C.W. Infrared spectra as a means of determining botanical sources of amber. Science, 1965, vol. 149, no. 3679, pp. 52–54. https://doi.org/10.1126/science.149.3679.52

7. Pastorelli G., Richter J., Shashoua Y. Evidence concerning oxidation as a surface reaction in Baltic amber. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2012, vol. 89, pp. 268– 269. https://doi.org/10.1016/j.saa.2012.01.003

8. Riquelme F., Ruvalcaba-Sil J.L., Alvarado-Ortega J., Estrada-Ruiz E., Galicia-Chávez M., Porras-Múzquiz H., Stojanoff V., Siddons P.D., Miller L. Amber from México: Coahuilite, Simojovelite and Bacalite. MRS Online Proceedings Library (OPL). 2014, vol. 1618, pp. 169– 180. https://doi.org/10.1557/opl.2014.466

9. Sonibare O.O., Agbaje O.B., Jacob D.E., Faithfull J., Hoffmann T., Foley S.F. Terpenoid composition and origin of amber from the Cape York Peninsula, Australia. Australian Journal of Earth Sciences, 2014, vol. 61, no. 7, pp. 979–985. https://doi.org/10.1080/08120099.2014.960897

10. Chekryzhov I.Y., Nechaev V.P., Kononov V.V. Blue-fluorescing amber from Cenozoic lignite, eastern Sikhote-Alin, Far East Russia: preliminary results. International Journal of Coal Geology, 2014, vol. 132, pp. 6–12. https://doi.org/10.1016/j.coal.2014.07.013

11. Poulin J., Helwig K. Inside amber: New insights into the macromolecular structure of Class Ib resinite. Organic Geochemistry, 2015, vol. 86, pp. 94–106. https://doi.org/10.1016/j.orggeochem.2015.05.009

12. Karolina D., Maja M.S., Magdalena D.S., Grażyna Ż. Identification of treated Baltic amber by FTIR and FT-Raman–a feasibility study. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2022, vol. 279, pp. 121404. https://doi.org/10.1016/j.saa.2022.121404

13. Xing Y.Y. Application of attenuated total reflectance infrared spectroscopy (ATR-FTIR) for amber identification and research. Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, 2016, vol. 36, no. 7, pp. 2066–2070. (in Chinese). https://doi.org/10.3964/j.issn.1000-0593(2016)07-2066-05

14. Park J., Yun E., Kang H., Ahn J., Kim G. IR and py/GC/MS examination of amber relics excavated from 6th century royal tomb in Korean Peninsula. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016, vol. 165, pp. 114–119. https://doi.org/10.1016/j.saa.2016.04.015

15. Wolfe A.P., McKellar R.C., Tappert R., Sodhi R.N., Muehlenbachs K. Bitterfeld amber is not Baltic amber: Three geochemical tests and further constraints on the botanical affinities of succinite. Review of Palaeobotany and Palynology, 2016, vol. 225, pp. 21–32. https://doi.org/10.1016/j.revpalbo.2015.11.002

16. Havelcová M., Machovič V., Špaldoňová A., Lapčák L., Hendrych J., Adam M. Characterization of Eocene fossil resin from Moravia, Czech Republic: Insights into macromolecular structure. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2019, vol. 215, pp. 176–186. https://doi.org/10.1016/j.saa.2019.02.058

17. Cotton L.J., Vollrath F., Brasier M.D., Dicko C. Chemical relationships of ambers using attenuated total reflectance Fourier transform infrared spectroscopy. Geological Society Special Publication, 2017, vol. 448, no. 1, pp. 413–424. https://doi.org/10.1144/sp448.22

18. Sroczyński D., Malinowski Z. Spectroscopic investigations (FT-IR, UV, 1H and 13C NMR) and DFT/TD-DFT calculations of potential analgesic drug 2-[2-(dimethylamino) ethyl]-6-methoxy-4-(pyridin-2- yl)-1 (2H)-phthalazinone. Journal of Molecular Structure, 2017, vol. 1150, pp. 614–628. https://doi.org/10.1016/j.molstruc.2017.09.020

19. Montoro O.R., Tortajada J., Lobato Á., Baonza V.G., Taravillo M. Theoretical (DFT) and experimental (Raman and FTIR) spectroscopic study on communic acids, main components of fossil resins. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020, vol. 224, pp. 117405. https://doi.org/10.1016/j.saa.2019.117405

20. Kocsis L., Usman A., Jourdan A.L., Hassan S.H., Jumat N., Daud D., Briguglio A., Slik F., Rinyu L., Futó I. The Bruneian record of “Borneo Amber”: A regional review of fossil tree resins in the IndoAustralian Archipelago. Earth-Science Reviews, 2020, vol. 201, pp. 103005. https://doi.org/10.1016/j.earscirev.2019.103005

21. Odriozola C.P., Garrido-Cordero J.A., Daura Luján J., Sanz M. Resincoated beads in Iberian Late Prehistory (3rd–2nd millennia BCE). Materials and Manufacturing Processes, 2020, vol. 35, no. 13, pp. 1420–1423. https://doi.org/10.1080/10426914.2020.1750634

22. Zhao T., Wang Y., Liu L., Li Y. Gemological and spectral characteristics of Mexican red blue amber. Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, 2021, vol. 41, no. 8, pp. 2618–2625. (in Chinese). https://doi.org/10.3964/j.issn.1000-0593(2021)08-2618-08

23. Cockx P., Tappert R., Muehlenbachs K., Somers C., McKellar R.C. Amber from a Tyrannosaurus rex bonebed (Saskatchewan, Canada) with implications for paleoenvironment and paleoecology. Cretaceous Research, 2021, vol. 125, pp. 104865. https://doi.org/10.1016/j.cretres.2021.104865

24. Musa M., Kaye T.G., Bieri W., Peretti A. Burmese amber compared using micro-attenuated total reflection infrared spectroscopy and ultraviolet imaging. Applied Spectroscopy, 2021, vol. 75, no. 7, pp. 839–845. https://doi.org/10.1177/0003702820986880

25. López-Morales G., Espinosa-Luna R., Frausto-Reyes C. Optical characterization of amber from Chiapas, Mexico. Proceedings of SPIE, 2013, vol. 8873, pp. 887311. https://doi.org/10.1117/12.2024701

26. Rao Z., Dong K., Yang X., Lin J., Cui X., Zhou R., Deng Q. Natural amber, copal resin and colophony investigated by UV-VIS, infrared and Raman spectrum. Science China Physics, Mechanics and Astronomy, 2013, vol. 56, no. 8, pp. 1598–1602. https://doi.org/10.1007/s11433-013-5144-z

27. Pastorelli G., Shashoua Y., Richter J. Surface yellowing and fragmentation as warning signs of depolymerisation in Baltic amber. Polymer Degradation and Stability, 2013, vol. 98, no. 11, pp. 2317– 2322. https://doi.org/10.1016/j.polymdegradstab.2013.08.009

28. Truică G., Ditaranto N., Caggiani M., Mangone A., Liţescu S., Teodor E., Sabbatini L., Radu G. A multi-analytical approach to amber characterisation. Chemical Papers, 2014, vol. 68, no. 1, pp. 15–21. https://doi.org/10.2478/s11696-013-0415-8

29. Havelcová M., Machovič V., Linhartová M., Lapčák L., Přichystal A., Dvořák Z. Vibrational spectroscopy with chromatographic methods in molecular analyses of Moravian amber samples (Czech Republic). Microchemical Journal, 2016, vol. 128, pp. 153–160. https://doi.org/10.1016/j.microc.2016.04.010

30. Cai L., Wang Y., Liu X., Huang Y. Spectroscopic characteristics of amber, copal resin and the improved derivatives. Huadong Ligong Daxue Xuebao/Journal of East China University of Science and Technology, 2020, vol. 46, no. 2, pp. 227–233. (in Chinese). https://doi.org/10.14135/j.cnki.1006-3080.20190107002

31. Colomban P., Franci G.S., Koleini F. On-site Raman spectroscopic study of beads from the necropolis of Vohemar, Northern Madagascar (>13th C.). Heritage, 2021, vol. 4, no. 1, pp. 524–540. https://doi.org/10.3390/heritage4010031

32. Rygula A., Klisińska-Kopacz A., Krupska P., Kuraś E., del HoyoMeléndez J.M. The surface degradation of Baltic amber: The depthprofiling analysis and its application to historical object. Journal of Raman Spectroscopy, 2021, vol. 52, no. 1, pp. 123–129. https://doi.org/10.1002/jrs.5942

33. Dai L.-L., Shi G.H., Yuan Y., Jiang X., Liu W.Q. Influences on baltic amber spectral characteristics under thermal optimization with multiple conditions. Spectroscopy and Spectral Analysis, 2021, vol. 41, no. 4, pp. 1300–1305. (in Chinese). https://doi.org/10.3964/j.issn.1000-0593(2021)04-1300-06

34. Jehlička J., Edwards H.G.M., Villar S.E.J., Frank O. Raman spectroscopic study of the complex aromatic mineral idrialite. Journal of Raman Spectroscopy, 2006, vol. 37, no. 7, pp. 771–776. https://doi.org/10.1002/jrs.1497

35. Wang Y., Shi G.H., Shi W., Wu R.H. Infrared spectral characteristics of ambers from three main sources (Baltic, Dominica and Myanmar). Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, 2015, vol. 35, no. 8, pp. 2164–2169. (in Chinese). https://doi.org/10.3964/j.issn.1000-0593(2015)08-2164-06

36. Gaigalas A., Halas S. Stable isotopes (H, C, S) and the origin of Baltic amber. Geochronometria, 2009, vol. 33, no. 1, pp. 33–36. https://doi.org/10.2478/v10003-009-0001-9

37. Bogdasarov M.A., Bogdasarov A.A., Martirosyan O.V. Infrared spectrometry of fossil resins from cretaceous deposits of Bulgaria. Vestnik of the Institute of Geology of the Komi Science Center of the Ural Branch of the Russian Academy of Sciences, 2011, no. 4(196), pp. 15–17. (in Russian)

38. Martirosyan O.V., Bogdasarov M.A. Fossil resins: diagnostics, classification and structural transformation under the thermal influence. Vestnik of the Institute of Geology of the Komi Science Center of the Ural Branch of the Russian Academy of Sciences, 2014, no. 4(232), pp. 10–15. (in Russian)

39. Cockx P., Tappert R., Muehlenbachs K., Somers C., McKellar R.C. Amber from a Tyrannosaurus rex bonebed (Saskatchewan, Canada) with implications for paleoenvironment and paleoecology. Cretaceous Research, 2021, vol. 125, pp. 104865. https://doi.org/10.1016/j.cretres.2021.104865

40. Pastorelli G., Shashoua Y., Richter J. Hydrolysis of Baltic amber during thermal ageing — An infrared spectroscopic approach. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013, vol. 106, pp. 124–128. https://doi.org/10.1016/j.saa.2012.12.072

41. Pagacz J., Stach P., Natkaniec-Nowak L., Naglik B., Drzewicz P. Preliminary thermal characterization of natural resins from different botanical sources and geological environments. Journal of Thermal Analysis and Calorimetry, 2019, vol. 138, no. 6, pp. 4279–4288. https://doi.org/10.1007/s10973-019-08157-0

42. Peris-Díaz M.D., Łydżba-Kopczyńska B., Sentandreu E. Raman spectroscopy coupled to chemometrics to discriminate provenance and geological age of amber. Journal of Raman Spectroscopy, 2018, vol. 49, no. 5, pp. 842–851. https://doi.org/10.1002/jrs.5357

43. Naglik B., Mroczkowska-Szerszeń M., Dumańska-Słowik M., Natkaniec-Nowak L., Drzewicz P., Stach P., Żukowska G. Fossil resins–constraints from portable and laboratory near-infrared raman spectrometers. Minerals, 2020, vol. 10, no. 2, pp. 104. https://doi.org/10.3390/min10020104

44. Jehlička J., Jorge Villar S.E., Edwards H.G.M. Fourier transform Raman spectra of Czech and Moravian fossil resins from freshwater sediments. Journal of Raman Spectroscopy, 2004, vol. 35, no. 8-9, pp. 761–767. https://doi.org/10.1002/jrs.1191

45. Li X., Wang Y., Shi G., Lu R., Li Y. Evaluation of natural ageing responses on Burmese amber durability by FTIR spectroscopy with PLSR and ANN models. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2023, vol. 285, pp. 121936. https://doi.org/10.1016/j.saa.2022.121936

46. Brody R.H., Edwards H.G.M., Pollard A.M. A study of amber and copal samples using FT-Raman spectroscopy. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2001, vol. 57, no. 6, pp. 1325–1338. https://doi.org/10.1016/s1386-1425(01)00387-0