Sampling the northern boundary of the North Atlantic:Cruise 159 of RRS Charles Darwin for RAPID Nick McCave and the crew of CD159*, Dept of Earth Sciences, University of Cambridge, Downing Street, Cambridge. Cruise Charles Darwin 159 was primarily devoted to coring with ancillary CTD work in the North Atlantic between Scotland and Newfoundland. The sampling program was most successful, due to unusually good weather in July (1-30, 2004), recovering 30 box cores, 19 piston cores, 6 kasten cores, 9 other short gravity cores and 20 CTD casts as well as 28 surface water samples for trace metals, 28 for plankton and isotopes, and 20 for filtered foraminifera. Objectives are to generate palaeoceanographic records of hydrographic changes (temperature, salinity, nutrients, flow speed) associated with sharp climate transitions of the last 16 ka seen in the Greenland ice cores. Samples and CTD casts were also taken at sites of former current meter deployments to calibrate proxies for flow speed and other hydrographic variables. Sampled areas were north of Rockall, S. Iceland slope and rise, Gardar Drift (E. Reykjanes ridge), S.E. Greenland margin, Eirik Drift (S. of Greenland), and Hamilton Spur and Orphan Spur off Labrador. Examples of CTD data gathered Examples of 3.5 kHz and Swath data Far left Potential temperature-salinity diagram for Stations CD159-004,005,006,007,016,018 in the Iceland Basin. Contours show o Left. Potential temperature-salinity diagram for deep waters west (in red colours) and east (in blue-green colurs) of the Reykjanes Ridge; Contours show o The swath echo sounding system was run continuously and much of the output was processed, especially around the coring sites. An example of the swath coverage is given here for the sites on mid-Gardar Drift. This covers the area cored by us (stations 19-21) and Marion Dufresne MD99-2251 in 1999. The difference in characteristic -S features of LSW occurs because the properties of the overflow waters to the west and east of the Reykjanes Ridge are different (Left above). DSOW is fresher than both LSW and ISOW at the stations sampled and therefore causes a salinity maximum in the -S diagram west of the Ridge. The characteristics of LSW in the Irminger Basin (Left, A) are more complex than in the Iceland Basin given that the core of LSW in the Iceland Basin is on the o = 27.75 surface at  = 3 S = 34.95. Salinities up to nearly S = 35 are seen in the Labrador Sea stations (Left, B) and, in the Irminger Basin, the o = 27.75 surface is more saline than waters above and below. The 3.5 was run continuously from the beginning of the cruise. Data was recorded digitally and on small scale paper rolls. An example shown below is processed data (by Sally Hunter) from the lower slopes of Eirik Drift showing low mud waves indicative of current-controlled sedimentation Left. Potential temperature-salinity diagram for Labrador Sea and Irminger Basin: (A) Stations CD159- 022, 023, 024, 025, 026, 032, (B )- 032, 036; Contours show o Sampling stations – NE and NW Atlantic Correlation of cores from deep Eirik drift (13P-14P), and kasten & piston from the same site (Sta 39) on Hamilton Spur, Labrador margin Ship’s track (with Julian Day markers) Correlations via mag- netic susceptibility and volcanic ashes, the Vedde and Saks-unarvatn. At Sta 39 Ash I may be Vedde, (but is in Saksunar position on MS) the other not identified. Saks’vtn End YD Vedde Examples of Piston cores obtained: Magnetic susceptibility and Lightness (L*) data used to establish correlation between 13P and 14P at Stations 34 and 35 respectively Some of the 19 piston cores obtained show a very thick Holocene section and the two major volcanic ash markers - the Vedde (11.98 ka, red line) and Saksunarvatn (10.18 ka, green line). Interestingly the core here with the thinner Holocene (13P) shows the thicker section between the two ashes which, at a sedimentation rate of 122 cm/ka, should yield a very high resolution analysis of the transition from cold to warm coming out of the Younger Dryas (~ 11.51 ka, blue line) * Prof. Harry Elderfield, Dr Luke Skinner, Mike Cook, Rob Pugh, DavidThornalley (University of Cambridge, Dept. of Earth Sciences), Dr Ian Hall, Lizzy Molyneaux, Helena Evans (University of Cardiff, Dept. of Earth Sciences), Dave Harding (University of Oxford, Dept. of Earth Sciences), Sally Hunter (University of Southampton, SOES), Matt Carroll (University of Nottingham, Inst. of Genetics), Jez Evans, Terry Edwards, Gareth Knight, Rhys Roberts, & Darren Young (UKORS, SOC, Southampton).