(Table 2) Radiocarbon dates of sediment cores obtained during Bio Hespérides cruise SVAIS and OGS Explora cruise EGLACOM between 2007-2008

A high-resolution paleomagnetic and rock magnetic study has been carried out on sediment cores collected in glaciomarine silty-clay sequences from the continental shelf and slope of the southern Storfjorden trough-mouth fan, on the northwestern Barents Sea continental margin. The Storfjorden sedimentary system was investigated during the SVAIS and EGLACOM cruises, when 10 gravity cores, with a variable length from 1.03 m to 6.41 m, were retrieved. Accelerator mass spectrometry (AMS) 14C analyses on 24 samples indicate that the cores span a time interval that includes the Holocene, the last deglaciation phase and in some cores the last glacial maximum. The sediments carry a well-defined characteristic remanent magnetization and have a valuable potential to reconstruct the paleosecular variation (PSV) of the geomagnetic field, including relative paleointensity (RPI) variations. The paleomagnetic data allow reconstruction of past dynamics and amplitude of the geomagnetic field variations at high northern latitudes (75°-76° N). At the same time, the rock magnetic and paleomagnetic data allow a high-resolution correlation of the sedimentary sequences and a refinement of their preliminary age models. The Holocene PSV and RPI records appear particularly sound, since they are consistent between cores and they can be correlated to the closest regional stacking curves (UK PSV, FENNOSTACK and FENNORPIS) and global geomagnetic model for the last 7 ka (CALS7k.2). The computed amplitude of secular variation is lower than that outlined by some geomagnetic field models, suggesting that it has been almost independent from latitude during the Holocene.

本研究针对巴伦支海西北缘南部斯托尔峡湾（Storfjorden）槽口扇大陆架与陆坡区域的冰海相粉砂质黏土序列采集的沉积岩心，开展了高分辨率古地磁学（paleomagnetism）与岩石磁学（rock magnetism）研究。斯托尔峡湾沉积体系的调查由SVAIS与EGLACOM航次完成，期间共获取10根长度介于1.03 m至6.41 m之间的重力岩心。对24个样品开展的加速器质谱法（Accelerator mass spectrometry, AMS）¹⁴C测年分析结果显示，该批岩心的沉积时间跨度涵盖全新世、末次冰消期，部分岩心甚至包含末次盛冰期地层。沉积物具有清晰可辨的特征剩余磁化强度（characteristic remanent magnetization），具备重建地磁场古长期变化（paleosecular variation, PSV）——包括相对古强度（relative paleointensity, RPI）变化——的良好潜力。基于该套古地磁学数据，可重建北纬75°至76°这一高纬度区域的地磁场变化历史、动力学过程与变化幅度。与此同时，岩石磁学与古地磁学数据可实现沉积序列的高分辨率对比，并优化其初步年代模型。全新世的古长期变化与相对古强度记录尤为可靠：不同岩心间的记录一致性良好，且可与邻近的区域堆叠曲线（regional stacking curves，UK PSV、FENNOSTACK与FENNORPIS）以及过去7千年的全球地磁模型（CALS7k.2）进行对比关联。测算得到的长期变化幅度低于部分地磁模型的预测结果，这表明全新世期间地磁场长期变化几乎不受纬度影响。