The Storegga Slide: architecture, geometry and slide development

The detailed mapping of the Storegga Slide morphological elements and the analyses of the slide development are based on high-quality acoustic and sampling data sets acquired through a cooperation between academia and the petroleum industry. The Storegga Slide has affected an area of c. 95 000 km2 and a sediment volume of minimum 2400 km3 and maximum 3200 km3 has been displaced with c. 250 km3 deposited as turbidite sediments in the Norway Basin. This volume places the Storegga Slide event as one of the world largest exposed submarine slides. The Storegga Slide can be divided into six distinctive morphological provinces. Associated, and superimposed, on these provinces a total of 63 slide lobe phases have been identified and mapped. The morphological investigations have furthermore made it possible to generate a set of numerical values for statistical analysis of slide sediment rheology. This knowledge also makes it feasible to model the Storegga Slide. The analyses of the slide have revealed that the slide has developed through a retrogressive process starting most probably on the lower slope. The most likely location for initializing is in an area close to the Faroe–Shetland Escarpment

North Atlantic-Fennoscandian Holocene climate trends and mechanisms

To investigate the mechanisms behind Holocene regional climate trends from north of 58°N in the North Atlantic-Fennoscandian region Principal Component Analysis (PCA) was performed and a temperature anomaly stack produced from 81 proxy derived summer temperature time series from 74 sites. The PC results show distinctly different trends for near-surface versus surface temperatures, demonstrating the importance of handling these separately. The first PC of weighted sea surface summer temperature time series and continental time series explains 45 ± 8% of the variance, where the uncertainty is the standard deviation of the distribution of variance explained across the 1000 age-uncertain ensemble members. PC1 has a relatively uniform expression over the whole region, closely following the summer insolation at 65°N. The second PC explains 22 ± 4% of the variance and shows a non-uniform expression, with loadings in opposite directions in the northern and southeastern parts of the region. Comparing the PC time series with model runs and with the timing of the demise of the Laurentide Ice Sheet (LIS), suggest that this pattern reflects both topographic and albedo effects of the LIS as well as release of meltwater into the North Atlantic and Arctic Oceans. Comparing the stack of gridded records with published global stacks reveals an unusual Holocene temperature development in the North Atlantic-Fennoscandian region most likely resulting from the location relative to the decaying LIS

Reconstructions of surface ocean conditions from the North East Atlantic and Nordic Seas during the last millennium

We undertake the first comprehensive effort to integrate North Atlantic marine climate records for the last millennium, highlighting some key components common within this system at a range of temporal and spatial scales. In such an approach, careful consideration needs to be given to the complexities inherent to the marine system. Composites therefore need to be hydrographically constrained and sensitive to both surface water mass variability and three-dimensional ocean dynamics. This study focuses on the northeast (NE) North Atlantic Ocean, particularly sites influenced by the North Atlantic Current. A composite plus regression approach is used to create an inter-regional NE North Atlantic reconstruction of sea surface temperature (SST) for the last 1000 years. We highlight the loss of spatial information associated with large-scale composite reconstructions of the marine environment. Regional reconstructions of SSTs off the Norwegian and Icelandic margins are presented, along with a larger-scale reconstruction spanning the NE North Atlantic. The latter indicates that the �Medieval Climate Anomaly� warming was most pronounced before AD 1200, with a long-term cooling trend apparent after AD 1250. This trend persisted until the early 20th century, while in recent decades temperatures have been similar to those inferred for the �Medieval Climate Anomaly�. The reconstructions are consistent with other independent records of sea-surface and surface air temperatures from the region, indicating that they are adequately capturing the climate dynamics of the last millennium. Consequently, this method could potentially be used to develop large-scale reconstructions of SSTs for other hydrographically constrained regions