Thursday, 3 July 2014

Pre-Cruise Planning Post

The cruise campaign plans are nearly complete, with meetings tomorrow to finalise coring locations to meet each of the campaign objectives. The map below shows the cores already in BOSCORF (British Ocean Sediment Core Research Facility) in red, key coring locations in green, and potential locations in yellow, though the campaign plan is subject to change with the weather and conditions at each location. These locations have been chosen to target the distal turbidite deposits from the large landslides on the Norwegian margin, many of which still have uncertain dates. The hope is that by heading to the high points within the deepest parts of the basin, we should find a thin turbidite deposit bounded by enough hemi-pelagite ("normal" marine mud) to date these turbidites accurately. One of the challenges this poses, is that deposition in this part of the basin can be as low as 5cm per thousand years, so in addition to looking for material to provide us with radiocarbon dates, we are also hoping to identify several tephra horizons within these cores. 

One of our other key objectives is to obtain several cores that will provide us with a high resolution climatic archive. The Nordic Seas are a key site for deep-water formation, the sinking of cold saline water, which drives the thermohaline circulation system, and as such, high resolution palaeoclimate records from these areas will allow us to refine our understanding of how these very large landslides fit with climate over the Holocene. The largest slide, the Storegga Slide, occurred during the last significant cold period, the 8.2 ka BP event (thousands of years before present), and it is unknown how, or even if, these two events are related to each other. 

The cruise team depart for Texel on the 2nd July, where we will meet the RV Pelagia and the remaining week will be spent gathering equipment, refining the coring plan and ensuring we have all the required background information we need. This includes swath bathymetry data from previous cruises to the region, courtesy of Julian Dowdeswell and Haflidi Haflidason, and TOBI data for the Traenadjupet Slide Scar from Julian. 

If you are interested in how these sediment cores are gathered, please see this short video detailing piston coring: 

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