Prof. Sarah Davies (University of Leicester):
Rivers, lakes, swamps and seas: exploring an early Carboniferous environment
Following the end-Devonian mass extinction, new terrestrial habitats developed and this was a major change in the Earth system. Examples of terrestrial environments and habitats are preserved in the early Mississippian (Carboniferous) sedimentary rocks that crop out across the borders of England and Scotland (the Ballagan Formation). Of particular significance are the new discoveries of land-based tetrapod taxa in the Ballagan Formation; these are of international importance because tetrapods were thought to be absent from this part of the geological record (an absence termed ‘Romer’s Gap’). Tetrapods preserved in Late Devonian strata were aquatic or semi-aquatic and fish-like whereas terrestrial tetrapod fauna recovered from late Mississippian successions had robust pentadactyl limbs. Until the last few years, there were very few fossil finds from the early Mississippian (Tournaisian).
An ongoing NERC-funded research project is investigating all aspects of the development and evolution of the early terrestrial ecosystem. Placing newly discovered tetrapods in their palaeoenvironmental context, this research investigates why these particular sedimentary successions, comprising fluvial, overbank and saline-hypersaline lake depositional settings, preserve such abundant fossil evidence. The study identifies the key sedimentary process acting to concentrate and preserve faunal and floral material as the frequent transport of fine-grained sediment across seasonally wet floodplains. These successions provide a unique opportunity to enhance our knowledge of this important phase in the development of terrestrial ecosystems.