Sunday, 9 March 2014

Photon-fickle fun foraging for flat fossils...

While it is often splendid viewing the beautifully fossilised remains of various vertebrates seemingly squished flat on a sedimentary bedding plane, such preservation generates some unique problems for palaeontologists to resolve. Life, as a whole... and usually when it is 'whole'... tends to be rather 3-dimensional (3D). While natural selection has managed to flatten many species to quite physically narrow ecological niches, us vertebrates tend to be a rather rotund bunch (although I often argue it is simply because I am just 'big-boned'). One of the biggest issues for such flattened offerings to the fossil record, is how do we reconstruct these critters back to their 3D state. If this were some 'Tom & Jerry' cartoon, I could see some comical use of an air-hose being inserted in a suitable orifice, but alas...the mineralised remains would not react well to such pneumatic coaxing. When we are studying the often complex jumble of crushed bones that seemingly stick like a meniscus to a slab of rock...we are often left scratching our heads.
A beautifully squished pterosaur on display at the Royal Ontario Museum (Canada), that is NOT the subject of our current synchrotron-based tomography project.
However, the advent of synchrotron-based imaging has provided a few possible avenues to inflate our rather deflated view of such fossils. The use of synchrotron-based elemental mapping, that we undertake at both Diamond and SSRL, might provide detailed information on surface chemistry and the distribution of bones (calcium and phosphate channels work well on this count...down to the calcium phosphate composition of bones)...but we need to dig deeper if we are to recover the 3D geometry of such bones. Once again, a synchrotron can come to the rescue...

Many will be familiar with medical CAT scanners that can yield glorious 3D slices through a live we are using synchrotron-based tomography to similarly tease the hidden geometry of a patient that is well-passed saving, but still well-worth imaging. At ESRF we are sat looking a beautifully squashed looks like it fell into a stony vice that imprinted its immortal remains firmly into a lithographic limestone. Some exquisite bones are visible at the surface, but many are still encapsulated by the encasing matrix that became this animals tomb for many millions of years (yes, I am trying to describe this animal, without giving too much away!). We are now teasing-out the very bones of this beastie with the splendidly powerful x-rays generated by the European Synchrotron here in Grenoble...a mere 26 hours to disinter this vertically challenged skeleton, that can then be digitally recovered from the vice-like grip of the fossil record. In the next few days we hope to learn more about a wonderful beastie that has been stuck within a rocky veneer for far too long!

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