Geomagnetiska fältets fluktuationer i norra Europa under sen Holocen: synkronisering till den trädrings kalibrerade kol-14 tidskalan
Tidsperiod: 2011-01-01 till 2013-12-31
Projektledare: Ian Snowball
Budget: 2 600 000 SEK
Palaeomagnetic data of the highest quality will be produced by this project and used to track changes in the direction and intensity of the geomagnetic field over the Earth´s surface in the northern hemisphere during the last 6000 years. The results will (i) improve time varying geomagnetic field models and (ii) test the constantly resurfacing hypothesis of a link between internally driven variability in the structure of the magnetosphere and climate change. The project will integrate palaeomagnetism, radiocarbon wiggle-matching and tephrochronology, with the aim to secure palaeomagnetic secular variation features identified over tens of degrees of longitude to the globally accepted radiocarbon calibration timescale. The applicants will supervise a PhD student, who will apply these methods to (i) two varved lake sediment sequences in Sweden, including the recently discovered high-resolution site of Gyltigesjön in southern Sweden, (ii) sediments from the classic, but poorly dated, palaeomagnetic site of Lake Windermere in the UK (in collaboration with the British Geological Survey and the National Oceanography Centre). Preliminary data have been used to re-date one of the largest changes in the Holocene geomagnetic field to 2465 cal. yrs BP, with a precision of two decades.