Characterization and Analysis of Fossil Resins

Fossil resins, commonly known as amber, represent polymerised plant exudates that have undergone chemical and physical transformations over geological timescales. Their study integrates geochemistry, palaeobotany and analytical chemistry to unravel botanical sources, diagenetic pathways and palaeoenvironmental contexts. The molecular composition of resins is dominated by terpenoid compounds, which polymerise and cross-link to produce a macromolecular matrix, trapping low-molecular-weight species and biological inclusions. Characterisation techniques range from spectroscopic methods (infrared and fluorescence microspectroscopy) to thermal approaches (pyrolysis and evolved gas analysis-mass spectrometry), often combined with multivariate statistics or spectral unmixing to discriminate resin types and assess maturation. Advances in provenance studies and classification—such as refined definitions for copal versus amber—have clarified the temporal and botanical frameworks, while new imaging and chemical protocols have enhanced the resolution of both organic and inorganic components. These developments deepen our understanding of resin production in past ecosystems, inform reconstructions of ancient forests and support conservation of cultural artefacts containing archaeological amber.

Research from Nature Portfolio

Recent studies have established precise protocols for two-photon excitation fluorescence microspectroscopy applied to amber-embedded specimens. This approach yields high-sensitivity excitation and emission spectra at submicrometre resolution, enabling linear spectral unmixing to distinguish the resin matrix from preserved tissues such as lignin and cellulose, and to detect potential chlorophyll derivatives. These methods promise insights into plant fossilisation processes and broader applications to non-plant palaeobiological material. In parallel, a revised framework for defining subfossil and fossil resins has been proposed, introducing “copal” as an archive spanning the Pleistocene to 1760 AD, and “Defaunation resin” for post-Industrial-Revolution exudates. The same study delineates the “Latest Amber Bioinclusions Gap” as a paucity of resin inclusions from the late Miocene to end Pleistocene, thus concentrating future research on key intervals of palaeobiological significance.

Characterization and Analysis of Fossil Resins publication trend

The graph below shows the total number of articles in characterization and analysis of fossil resins across all publications each year (not limited to Nature Index journals).

Technical terms

Resin: Viscous plant exudate composed predominantly of terpenoid compounds that can fossilise to form amber.

Amber: Fossilised, polymerised resin preserved in geological deposits, often containing organic inclusions.

Copal: Subfossil resin defined as exuded between 2.58 Ma and 1760 AD, intermediate in maturity between resin and amber.

Terpenoids: Class of organic hydrocarbons built from isoprene units, major constituents of resins and ambers.

Fluorescence microspectroscopy: Imaging technique using laser excitation to obtain spatially resolved emission spectra from fluorescent materials.

Evolved gas analysis-mass spectrometry (EGA-MS): Analytical method that measures gases released during controlled heating to characterise molecular components of a sample.

Linear spectral unmixing: Computational approach that separates overlapping spectral signals into individual constituent spectra.

Cretaceous Resinous Interval (CREI): Geological interval from the Barremian to Campanian marked by widespread resin production and amber deposition.

Defaunation resin: Resin exuded since the onset of the Industrial Revolution, reflecting human-influenced forest conditions.

Latest Amber Bioinclusions Gap (LABG): Interval from the late Miocene to end Pleistocene characterised by a scarcity of bioinclusions in resin deposits.

References

1. Amber and the Cretaceous Resinous Interval. Earth-Science Reviews (2023).
2. Low- and high-molecular weight fractions of geological ambers detected by evolved gas analysis-mass spectrometry. Journal of Analytical and Applied Pyrolysis (2023).
3. Two-photon excitation fluorescence microspectroscopy protocols for examining fluorophores in fossil plants. Communications Biology (2024).
4. A revised definition for copal and its significance for palaeontological and Anthropocene biodiversity-loss studies. Scientific Reports (2020).