[1] Univ Plymouth, Sch Geog, Plymouth PL4 8AA, Devon, England
[2] Univ Nottingham, Sch Geog, Nottingham NG7 2RD, England
[3] British Geol Survey, NERC, Isotope Geosci Lab, Keyworth NG12 5GG, Notts, England
[4] Canakkale Onsekiz Mart Univ, Fac Sci & Arts, Dept Geog, TR-17020 Canakkale, Turkey