BOYCE, C. KEVIN1*, ANDREW H. KNOLL1, GEORGE D. CODY2, MARILYN L. FOGEL2, and ROBERT M. HAZEN2. 1Harvard University, 26 Oxford St., Cambridge MA, 02138; 2Carnegie Geophysical Laboratory, 5251 Broad Branch Rd. NW, Washington DC, 20015. - Microanalysis of elemental, isotopic, and organic chemistry of cellularly preserved fossils.
Permineralization can preserve fossils with cellular detail and the
ability to analyze their preserved organic matter without the loss of
spatial information would greatly increase the scope of questions that
can be investigated. A suite of microanalytical techniques has been
adapted for the study of fossil organic matter: electron microprobe
analysis providing micron-scale mapping of elemental abundances,
continuous flow isotope ratio mass spectrometry linked to an elemental
analyzer providing high resolution carbon isotopic abundances with
millimeter-scale spatial resolution, and X-ray spectromicroscopy
performed on cellulose acetate peels of fossils providing micron-scale
resolution of the distribution of organic functional groups. These
microanalytical techniques have complementary susceptibilities to
limitations, such as the abundance of organic matter and its extent of
degradation, the type of matrix mineral, and the relative
destructiveness of the analysis, and this system allows a balance
between the investigation of important paleobiological questions and
control studies that make reference to the physiologies of related
living organisms. Research initiatives can make use of both metabolic
and synthetic biochemistry to address paleobiological questions. In
addition to necessary studies of the taphonomy of organic matter, our
research has focused on the early evolution of the land flora,
including assessing the affinities of enigmatic fossils and
investigating the evolution of vascular cell types in early
tracheophytes.
Key words: isotopic geochemistry, organic geochemistry, paleobotany, taphonomy