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Projekt
The Archean to Paleoproterozoic transition as recovered in the FAR DEEP cores: LA-ICP-MS U-Pb geochronology of detrital zircons and accompanying provenance analysis of siliciclastic sedimentary rocks
Antragsteller
Professor Dr. Hans Heinrich Bahlburg
Fachliche Zuordnung
Paläontologie
Förderung
Förderung von 2008 bis 2013
Projektkennung
Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 75363574
During the Archaean-Palaeoproterozoic transition many global environmental changes occurred in the Earth’s system at the same time as tectonic reorganisations led to the break-up of the supercontinent Kenorland. Stratigraphic successions registering these events were successfully drilled in northern Russia (Fennoscandia) in the FAR-DEEP/ICDP project. - The first part of our study aimed at improving age constraints by Laser Ablation ICP-MS U-Pb geochronology on detrital zircons for three of these events recorded in the FAR DEEP cores. The events are the Huronian glaciation, the Lomagundi-Jatuli positive excursion of δ13C, and the Shunga event of enhanced deposition of Corg-rich sediments. Our data resulted in tighter temporal constraints for these events. In rocks marking the transition from the Lomagundi-Jatuli to the Shunga event we also found U-Pb ages, now confirmed by ID-TIMS, which are too young regarding their stratigraphic position, and which are difficult to explain in view of the allegedly undisturbed stratigraphic succession. These need to be verified by additional analyses.- Also, the provenance of the analysed zircons and the nature of the recycled, partly Palaeoarchaean crust will be established by LA ICP-MS Hf isotope analysis on dated zircons and by ion microprobe analysis of heavy minerals like tourmaline and rutile.
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