Geochemical characterization of high molecular weight material isolated from late cretaceous fossils

The appraisal of geochemical analyses obtained from the organic component isolated from fossils is often limited by the ability to assess the origins of this material. This study reports the first carbon and nitrogen isotope and amino acid analyses of high molecular weight organic material isolated from bones and teeth of reptiles from the Judith River Formation, Alberta. Amino acid analysis of the HC1 hydrolyzates of these samples show an abundance of glutamic acid and aspartic acid which suggests good preservation. Evidence of a remnant of the original organic material is indicated by the apparent presence of hydroxyproline, a common amino acid in bone collagen. Amino acid D/L values are less than 0.25. This may result from incorporation of the amino acids into a high molecular weight organic materials. Stable carbon and nitrogen isotope values range between - 26.0 and -24.0% ₀ and 2 and 12% ₀, respectively. Reptiles of terrestrial and aquatic habitats have δ ^15N values which increase in the order of panoplosaur < hadrosaur < ceratopsid < tyrannosaur and aspideretes < champsosaur <crocodile < plesiosaur, respectively. These isotope signatures and trends in nitrogen values are typical of large modern herbivores and carnivores. The geochemical data suggest that a biochemical signal may be maintained throughout diagenesis. Such a signal could provide exciting new information pertaining to the comparative biochemistry, metabolism and ecology of fossil assemblages.