TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/28559/
CY  - Heidelberg
Y1  - 2020///
ID  - heidok28559
TI  - Spectroscopic isotope ratio analysis on speleothem fluid inclusions - analytics and paleoclimatic case studies
AV  - public
A1  - Weißbach, Therese
N2  - In this thesis the reconstruction of climatic conditions and paleotemperatures by the analysis of oxygen (?18O) and hydrogen (?2H) isotopes of fluid inclusions in speleothems from two different climatic zones (mid-latitudes and tropics) was performed. An extraction and processing system for fluid inclusion analysis with laser spectroscopy was developed and characterized with respect to the memory or amount effect. I could exclude disturbance effects and achieve a precision of 0.5? for ?18O and 1.5? for ?2H in replicated measurements with water volumes >0.2?l. The analysis of stable water isotopes allows the determination of paleotemperatures using the classic carbonate thermometer as well as the application of the ?2H/T - relationship with a precision down to ±0.45°C. For the western tropical Atlantic I identified a cooling during the Heinrich stadials (2 and 3) of ~3°C applying the classic carbonate oxygen isotope thermometer. Beyond direct temperature determination, the analysis of fluid inclusions provides information about karst water availability during stalagmite formation. For instance, the ?18O and ?2H values of two speleothems from Germany and Puerto Rico, show slopes of +2.3±1.1 and +3.7±0.2, respectively, that are significantly
lower compared to meteoric water lines (slope of ~8). This clear evaporation signal in the related fluid inclusions probably indicates evaporation effects (cave or epikarst), which are enhanced during drier climate conditions.
ER  -