Grant: Discovery Grants Program - Individual

Earth history is recorded in sedimentary basins where detritus from surrounding lands accumulates along with particulate organic matter and biological remains that may later be transformed into oil, natural gas, or coal. The margins of basins are transitional areas where accumulation of detritus is regulated by fluctuating sea levels, wave and current erosion, and downslope transport of suspended sediment by gravity-driven density underflows called ""turbidity currents"". The small seas of western Turkey (Black Sea, Marmara Sea, Aegean Sea) provide unparalleled opportunities to study geological processes important to the evolution of ALL sedimentary basins. Periods of isolation of low-salinity water bodies from the global ocean, then reconnection, have generated strong chemical and biological signals in the sedimentary record that can be used to understand geological processes. Hiscott and collaborator Aksu have collected >100 sediment cores totaling >400 m in combined length in this region - several cores will be used for new graduate-student projects. A key part of the 2009-2014 research is monitoring of a unique saline underflow formed by dense Mediterranean water as it crosses the SW shelf of the low-salinity Black Sea. This is the only place on Earth where a density underflow with properties similar to deep-sea turbidity currents is assessible for monitoring in water depths <100 m. Key questions relate to the velocity structure of such currents and their interaction with bends of sinuous channels so common in the deep sea. The associated channel network was mapped in 2005 & 2008; a sophisticated program of monitoring and seabed sampling will be undertaken in 2010 & 2011 with British collaborators using the UK autonomous submersible AutoSub3. Other work in the region will address questions of organic-matter deposition, sources of sediment in the saline-channel banks and bars, and timing of major floodwater events in the last 15,000 years as the climate of central Asia shifted from a glacial to interglacial mode. Two current PhD students and four new students will receive training in multiple aspects of marine geoscience - several will participate in research cruises and learn practical sampling and surveying methods.