Deuterium exchangeability in modern and fossil plant resins. (15th October 2018)

• Record Type: Journal Article
• Authors: González Arismendi, Gabriela; Tappert, Ralf; McKellar, Ryan C.; Wolfe, Alexander P.; Muehlenbachs, Karlis
• Is Part Of: Geochimica et cosmochimica acta. Volume 239(2018)
• Page Start: 159
• Page End: 172
• Publication Date: 2018-10-15
• Subjects: Amber -- Conifer resin -- Deuterium -- Isotopic exchange -- Paleoenvironment; Geochemistry -- Periodicals; Meteorites -- Periodicals; Géochimie -- Périodiques; Météorites -- Périodiques; Geochemie; Astrochemie; Electronic journals; 551.905
• DOI: 10.1016/j.gca.2018.07.033
• Languages: English
• ISSNs: 0016-7037

Abstract

Abstract: Deuterium exchange experiments on modern and fossil plant resins (amber) were conducted to assess to what extent diagenetic alteration can overprint the stable hydrogen ( δ 2 H) and carbon ( δ 13 C) isotopic composition of these materials. Pairs of resins and amber fragments were placed together with deuterated water in sealed quartz-glass tubes to assure that all samples were exposed equally to the chosen experimental conditions. Experiments lasting up to one year were carried out at temperatures of 50 °C and 90 °C using water artificially enriched in deuterium ( 2 H concentrations between 2861 and 8845 µg/g), which resulted in deuterium concentrations measured in samples well above natural concentrations (i.e., 2 H ∼ 143 µg/g). Modern resins recorded a mean deuterium exchange with deuterium-enriched water of 2.0 ± 0.1%, compared to 1.3 ± 0.2% observed in their fossil counterparts. No significant changes were observed in the δ 13 C of modern and fossil resins during the experiments. Overall, these results indicate that the extent of 2 H isotopic exchange in resins is minor and apparently occurs prior to polymerization. Consequently, the stable isotopic composition of fossil resins has the potential to serve as a useful proxy for paleoenvironmental reconstructions, given the widespread distribution of ambers in the Mesozoic and Cenozoic fossil record.