ABSTRACTS
Brian Thomas,
Arthur Chadwick,
and Stephen Taylor
Molecular, and even whole tissue preservation, including bone collagen sequences and blood vessels from Cretaceous bone samples, are described in a growing body of technical literature. Separate studies also describe primary isotopes from many of the same geological formations as those that have fossils with molecular preservation.
To investigate what might have led to the co-occurrence of molecular and isotopic preservation, we collected and analyzed fifteen stable carbon isotope results from three bone fractions (organic collagen, inorganic bioapatite, and a mixture of both in “bulk”), each isolated from six Cretaceous dinosaur bone specimens. Assessments of preservation evaluated the endogeneity of our isotope ratios. Broad offsets between bioapatite and collagenous extracts were inconsistent with secondary isotope ratios (i.e., contamination), and largely consistent with biological ratios (i.e., ratios expected in fresh bone). Our results include the first stable carbon isotope ratios from collagen extracts of dinosaur bone. Co-occurrence of primary carbon isotope ratios and biomolecules suggest two aspects of their diagenetic history. Firstly, it appears that any ancient hydrothermal fluids failed to facilitate the total decay of organics, nor to totally randomize carbon isotopes. This result is consistent with a relatively recent burial. Lastly, given that the well-characterized decay of bone collagen even under ideal conditions limits it to fewer than a million years at 10°C, these fossils likely experienced a much more brief burial history than mainstream sources cite.