Professor Tony Fallick, Scottish Universities Environmental Research Centre
Around 2.2 billion years ago, the Earth experienced a series of dramatic upheavals which accompanied the transition from a reducing to an oxidising ocean/atmosphere system. The global carbon cycle was perturbed to an extent unparalleled before or since, with the changes documented in the stable carbon isotope record of carbonate (δ13Ccarb). From concretions in sediments, there is evidence that the manner in which organic matter is remineralised under- went radical change. However, the exact sequence of events leading to this “greatest pollution event of all time” (Lovelock) is not yet clear, and several aspects are paradoxical. It is an open question whether there was one or several excursions to high (δ13Ccarb); the end of the high δ13C record is reasonably well-established at 2056 ± 6 Ma, but its inception is not well defined, so that only a minimum duration (~ 140 My) is known. The interplay of the records of oxidised carbon (as carbonate) and reduced carbon (as organic matter) is especially problematic. Recent drilling in Arctic Russia by the International Continental Scientific Drilling Program FAR-DEEP Consortium has produced a marvellous new archive of 3.6 km of drillcore with which these and other issues are being addressed.
The lecture will be preceded by the society’s AGM and followed by the traditional Christmas social, with nibbles and drinks.