Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers [Elektronische Ressource] / put forward by Barbara Luise May

Dissertationsubmitted tothe Combined Faculties forthe Natural Sciences and for Mathematicsof the Ruperto Carola University of Heidelberg, Germanyfor the degree ofDoctor of Natural Sciencesput forward byDipl. Phys. Barbara Luise MayBorn in OchsenfurtOral examination: 02.12.2009Radiocarbon microanalysis on ice impuritiesfor dating of Alpine glaciersReferees: Prof. Dr. Werner Aeschbach HertigProf. Dr. Augusto ManginiAbstractThe main objective of this thesis is the deployment of radiometric dating on Alpine ice archives, where14conventional, stratigraphical dating techniques fail. To this end a C analysis of particulate and, ina novel attempt, also of dissolved organic carbon contained in the ice matrix is developed. Aimed atminimizing the required ice sample size, the designed ice processing line allows for handling of up to14700 g ice and is shown to involve blank levels small enough to ensure reliable C analyses down to amodern carbon fraction of f = 0.33 at a minimum sample mass of about 20μg carbon.mDeployment of the system at the high altitude drilling area Colle Gnifetti (Monte Rosa, 4 550 m.a.s.l.)and, in contrast, to an ice core at the low altitude Vadret dal Corvatsch ice cap (Upper Engadin,143 433 m.a.s.l.) reveals a quite significant C excess, not explained by any blank contribution and14in contrast to the expected age range.