Sunday, 9 October 2011

GSA-o-saurus minneapolensis

My time in the USA working at the University of Pennsylvania sadly drew to a close last month. My year in Philadelphia was quite an eye-opener as to how the US University system differs from that in the UK. I shipped myself back to the University of Manchester...and my feet have not stopped since. Finally, I find a few minutes of peace and quiet to sit and write my blog...ironically, at a meeting of the Geological Society of America (GSA) in Minneapolis, USA. Yes, I just jumped back on a flight to the US for this vast (~3000 scientists) conference. I may have told tales of the Society of Vertebrate Paleontology (notice the dropped 'a' in palaeo...its a US thing), who meets annually and to which I usually attend...but this years choice of conference was GSA, who kindly invited me to give a talk on behalf of the Manchester PalAeontology Research Group.

The topic of my talk for this meeting are chemical ghosts of past life....and no, I've not been spending too much time reading Harry Potter! The authors of this talk are myself, Roy Wogelius and Uwe Bergmann, as multiple authors are often the case for such international meetings. Without the team, such science could not happen....especially when working with a synchrotron light source!

Our abstract is a tad dense, but I thought I should post it anyway. It gives you an insight to the wonderful world of conference abstracts, where you have a paragraph or two to sum-up your last 7 years work. Not easy!

Title: Synchrotron light reveals chemical ghosts of past life.

Authors: Manning, P. L*., Bergmann, U. and Wogelius, R. A.
* is presenting paper.

Abstract: Multidisciplinary approaches to the analyses of fossilised soft tissue have shown that endogenous organic compounds can survive through geologic time. The work presented here will show how coupling synchrotron-based X-ray and infra-red methods can serve to non-destructively resolve the survival of organic compounds derived from fossil and extant organisms, but also how spectroscopic details can assist in understanding the chemistry of exceptional preservation. Here we use Fourier Transform Infrared Spectroscopy (FTIR) to spatially resolve organic functional groups within Eocene (~50mya) to Cretaceous (~120mya) aged fossils that show biological control on the distribution of amide and sulfur compounds. These compounds are most likely derived from the original biomaterials present in the structures analysed because other non-fossil derived organic matter from the same geological formations do not show intense amide or thiol absorption bands. Infrared maps and spectra from the fossils are directly comparable to extant samples. X-ray Absorption Spectroscopy (XAS) of sulfur in some fossil tissues shows it is present in several oxidation states, including organic sulfur compounds and inorganic sulfate minerals. By using this information to tune the incident X-ray beam energy to a value below the critical excitation energy for inorganic sulfur, we were able to use Synchrotron Rapid Scanning X-ray Fluorescence (SRS-XRF) to discreetly map organic sulfur in discrete biological structures. This approach resolves fossil-derived organic compounds with striking detail. In addition, in this and other fossil specimens, XAS analysis of trace metals correlated with soft tissue structures indicating that a significant and in some cases dominant portion of trace metal inventory is organically coordinated within tissue residues. Quantitative synchrotron-based XRF point analyses are presented to show that concentrations determined within fossils are comparable to those of extant organisms, that phylogenetically bracket fossil samples. A taphonomic model involving ternary complexation between fossil bio-derived organic molecules, divalent trace metals, and silicate surfaces are here presented to explain the survival of the observed compounds.
Synchrotron light captures the phosphorus (P) of feathers and the iron (Fe) of fine feather structures.

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