GEOMAGNETISKA SIGNALER I ISHAVSSEDIMENT: KNÄCKA EN KVARTÄR GÅTA
Tidsperiod: 2015-01-01 till 2018-12-31
Projektledare: Ian Snowball
Medarbetare: Matthew O`Regan, Matthew O´Regan
Budget: 3 200 000 SEK
Leading to a PhD thesis, the project aims to (i) explain why Quaternary sedimentary sequences near the North Pole show evidence of a disproportionate number of geomagnetic polarity reversals, which have perplexed the geophysical community for over 40 years and (ii) generate new Holocene paleomagnetic data from an unsampled region that can test time varying geomagnetic field models. As an example of the currently confused situation, paleomagnetic data have been essentially ignored since the acclaimed IODP-ACEX expedition in 2003. Investment in the LOMROG and SWERUS-C3 expeditions, and analytical infrastructure in Sweden, provides the opportunity to study a series of sites and adopt an approach that integrates paleomagnetic data with those provided by other stratigraphic methods of correlation, such as stable isotopes and grain size. The sites, which extend from the North Pole to approximately 70 degrees N, span the theoretical influence of the influential Tangent Cylinder. We will test hypotheses that require the self-reversal of mineral phases, substantially delayed remanence acquisition caused by the deeply situated zone of sulphate reduction and the microbial synthesis of ferrimagnetic grains well below the seafloor. Comparisons between independently dated records of paleomagnetic secular variation and model predictions will improve our understanding of geomagnetic field variability in this challenging, but climatologically and geophysically dynamic region.