GRINDING TOMOGRAPHY: INSIGHTS INTO FOSSIL

Grinding tomography is a method with a high potential for paleontology. Although grinding tomography is a destructive method, it is sometimes worth to sacrifice a fossil. This is particularly the case when its internal features are not accessible, but needed for further interpretation. The body fossil is indeed gone after its application, but the scaled, three-dimensional virtual model, which can be composed from the dataset with 3D software, persists. The maximum size of objects is currently limited to 150 mm x 150 mm x 300 mm. Grinding tomography thus allows for the three-dimensional analysis of larger objects which can be hardly accessed by other methods.

Grinding tomography has been applied to fossils for a long time. Technical advances, however, meanwhile enable a very high resolution for the virtual fossils: It can be as fine as 5 µm per voxel, i.e. per data point in each dimension. The method can thus now be regarded as 3D microscopy, based on true-color images. It is here exemplified by earliest ontogenetic stages of ammonoids and bivalves, and by the reconstruction of bioerosion. Such virtual fossils allow insight into much more internal details than their originals. Datasets of tomographed fossils can even be registered as virtual fossils in official collections.

In the combination of high resolution models from even large objects, many applications of this method for geology and paleontology are feasible.

This poster presents the technical advances of a scientific project which was dedicated to these questions. Financial support by the German Science Foundation (DFG grant IF61/4-1) is gratefully acknowledged.