Kinetic fractionation of stable isotopes in speleothems [Elektronische Ressource] : laboratory and in situ experiments / presented by Daniela Polag

Dissertationsubmitted to theCombined Faculties for the Natural Sciences and for Mathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural Sciencespresented byDiplom-Geophysicist Daniela Polagborn in Frankfurt am Main, GermanyOral examination: 28.04. 2009Kinetic Fractionation ofStable Isotopes in Speleothems-Laboratory and In Situ Experiments-Referees:Prof. Dr. Augusto ManginiProf. Dr. Margot Isenbeck-Schro¨terAbstractIn recent years, stalagmites have become an important archive for paleoclimate. Several studies18 13aboutstable isotope records instalagmites showa simultaneousenrichmentofδ O andδ C alongindividualgrowth layers, whichis associated with kinetic isotope fractionation. However,to deducepaleoclimatic informationfromcalcitewhichisprecipitatedunderthesenon-equilibrium-conditions,it is important to improve the understandingof kinetic isotope fractionation in dependence of localconditions like temperature and drip rate. Within this research work, laboratory experiments with18 13synthetic carbonates were carried out under controlled conditions. The δ O and δ C evolution oftheprecipitatedcalcite werestudiedfordifferentexperimentparameterssuchastheinitialcomposi-tion of the solution, temperature and drip rate. In addition, in situ experiments were carried out intwo cave systems in Sauerland (Bunkerh¨ohle and B7-Ho¨hle).