A new archaeointensity dataset from the SW Pacific: implications for global geomagnetic field models

English Abstract:

Palaeomagnetic data from the southern hemisphere are sparse, in particular absolute intensity data. To improve global geomagnetic field models and to answer key questions about the millennial scale behaviour of the geodynamo, more data are needed from this region. We present new archaeointensity data from a collection of ceramics from the SW Pacific Islands including Fiji, Tonga, Papua New Guinea, New Caledonia and Vanuatu covering the past 3000 years. The microwave method has predominantly been used with a variety of experimental protocols including IZZI and Coe variants. Standard Thellier archaeointensity experiments using the IZZI protocol have also been carried out on selected samples. The data are presented and compared to regional predictions from the recently published pfm9k family of geomagnetic field models. We explore the influence of the new data on constraining global geomagnetic field models and investigate possible analogies to the present field and the South Atlantic Anomaly. We discuss the physical implications as well as the robustness of these new results.