Dating of sediments of Lake Biel, Switzerland, with unsupported Pb-210: Problems and results (Kongressschrift / Tagungsband) - Detailansicht

Grunddaten

Titel der Arbeit (title)	Dating of sediments of Lake Biel, Switzerland, with unsupported Pb-210: Problems and results
Titel der Zeitschrift bzw. Zeitung	Proceedings of the 3rd International Conference on Po and radioactive Pb isotopes
Erscheinungsjahr	2015
Seitenzahl (pages)	15
Publikationsart	Kongressschrift / Tagungsband

Inhalt
Abstract	In 2013 sediment cores with a length of about one meter were taken from two different basins of Lake Biel. Lake Biel is a mesotrophic lake with the tributaries River Aare which comes from glacier regions in the Alps and the River Zihl which is the outflow of the neighboring Lake Neuchâtel. Upstream on the River Aare the nuclear power plant Mühleberg (boiling water reactor) is located. The preparation of sediment samples and the sealing of samples against the diffusion of Rn-222 out of the sample is discussed and the Rn-loss is experimentally quantified. Total Pb-210, unsupported Pb-210 (via Pb-214 or Bi-214), Cs-137, Co-60, Be-7 and Am-241 in sediment samples were measured gamma-spectrometrically in order to establish a depth-age relation and to correlate it with independent time-markers. Pu-239/240 was determined via ICP-mass-spectrometry. Also, stable Pb, Fe, Mn, sediment bulk density, organic matter content and some naturally occurring radionuclides were determined. For dating of sediment layers with unsupported Pb-210 the Constant Flux-Constant Sedimentation Rate (CF-CSR), Constant Rate Supply (CRS) and Sediment Isotope Tomography (SIT) models were applied and intercompared. Discrepancies between Pb-models and other time-markers as well as results on sedimentation rates and the influence of turbidite layers on Pb-210 vertical distribution and depth-age relations are discussed.