1. 1Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260-3332, USA
2. 2School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth PL4 8AA, UK
3. 3Department of Geological Sciences and Center for Sedimentary Basin Studies, University of Alabama, Tuscaloosa, Alabama 35487-0338, USA
4. 4School of Geographical and Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UK