A section of the drill core from the prehistoric Lake Greifen (Photo: Yama Tomonaga, Eawag, University of Basel).A nuclear waste storage facility needs to be secure, even if glaciers were to churn down from the Alps into the midlands in a distant future. This is why Nagra arranged for a study of the sediments that had been deposited in former, deep glacial lakes. The layers are around 600,000 years old, making them much older than the last ice age, which was around 24,000 years ago. Good news for Nagra: it seems that the layers of stone lying beneath have not been eroded by ice since that time.Extent and depth of the glacial basin from the quaternary. The circle (QHST) denotes the drill site. (Source: from the publication). A team of researchers from the Aquatic Research Institute Eawag, the ETH Zurich and the Universities of Basel and Bern have investigated sediments drilled in the vicinity of the town of Bülach in the lowlands of the Canton of Zurich by the National Cooperative for the Disposal of Radioactive Waste (Nagra). The drill core is 278 metres long and describes nearly the entire geological history of the quaternary period, the most recent 2.6 million years of Earth’s history.
The drill site west of Bülach/ZH (Photo: Yama Tomonaga, Eawag, University of Basel).Sections from the sediment core ready for analysis of the pore space water using the portable mass spectrometer GE-MIMS (the ’Mini-Ruedi’) developed by Eawag (Photo: Yama Tomonaga, Eawag, University of Basel). Tomonaga, Y.; Buechi, M.
Fine sediments deposited in the prehistoric Lake Greifen (Photo: Yama Tomonaga, Eawag, University of Basel). W.; Deplazes, G.; Kipfer, R. (2024) First dating of an early Chibanian (Middle Pleistocene) glacial overdeepening in the Alpine Foreland using the 4He/U-Th method, Geology , doi: 10.1130/G52544.1 , Institutional Repository
