New geological discoveries

Synchrotron-based FTIR analysis of microscale preservational patterns in fossil conifer wood from the Sandwich Bluff Member of the López de Bertodano Formation, Vega Island, Antarctica. Image shows relative concentration of materials with spectral properties similar to lignin (2800 to 3050 cm-1) in fossil wood (in color) overlain on reflected light microscope image of the wood sample. Warm colors (red to yellow) in the overlay represent high concentrations of lignin along cell wall boundaries, where it would be expected to be highly concentrated. Arrows represent the axes of cell walls in the wood sample.

Synchrotron-based FTIR analysis of microscale preservational patterns in fossil conifer wood from the Sandwich Bluff Member of the López de Bertodano Formation, Vega Island, Antarctica. Image shows relative concentration of materials with spectral properties similar to lignin (2800 to 3050 cm-1) in fossil wood (in color) overlain on reflected light microscope image of the wood sample. Warm colors (red to yellow) in the overlay represent high concentrations of lignin along cell wall boundaries, where it would be expected to be highly concentrated. Arrows represent the axes of cell walls in the wood sample.

Project geologist Eric Roberts and his collaborators continue to make significant discoveries regarding the geology and ancient environment of Vega Island based on data he collected during our 2011 expedition. In particular, Eric has conducted strontium (Sr) isotopic analyses on fossil clam shells that he collected from throughout the Vega rock sequence, but most importantly from the lowermost layer of the Sandwich Bluff Member of the López de Bertodano Formation. This layer is of particular interest because it is the source of the duck-like fossil bird Vegavis, the only definitive representative of a modern avian group from the Mesozoic Era. The Sr values that Eric obtained support the longstanding hypothesis that the Sandwich Bluff Member and its fossils are at least predominantly latest Cretaceous in age.

Again making use of samples recovered during our productive 2011 campaign, Eric and colleagues are also studying the taphonomy of Cretaceous fossil-bearing deposits on Vega Island using synchrotron Fourier transform infrared microspectroscopy at the Australian Synchrotron. Analyses of fossil wood from the Cape Lamb Member of the Snow Hill Island Formation have elucidated microscale preservational patterns and established the presence of original organic material in these specimens.

Eric shared some of these results during his presentation at the Fourth International Palaeontological Congress in Mendoza, Argentina in 2014.