ALBERT

Description: This data set include (1) the detailed petrographic description of the diagnostic rock types used to infer the source areas of the material recovered from the Mar del Plata Canyon area (Western South Atlantic at 38° S) at Sites GeoB13830, GeoB22712, GeoB22717 and L45; and (2) the Acoustic Doppler Current Profiler (ADCP) data obtained from Sites GeoB22716, GeoB22717 and GeoB22732. A variety of gravel- to cobble-sized rocks, recovered from the Mar del Plata Canyon area and interpreted as ice-rafted debris, represents the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub-Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. In the Mar del Plata Canyon, a combination of local slope instability and strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit. Microscopic petrograohic determinations were done on thin sections to identify the mineralogical composition of the rocks. During cruise SONNE SO260-1, the hull mounted Ocean Surveyor Teledyne RDI Acoustic Doppler Current Profiler (ADCP) with a doppler shift of 38 kHz provided real-time current velocity profiles over a range from 38 to 1,200 m water depth. ADCP data from the lowest 10-15 % of the water column have been removed due to possible scattering caused by strong seafloor echo. Doppler shifts were converted into current velocities using real water sound velocities by means of Conductivity-Temperature-Depth (CTD) and Expendable Sound Velocimeter (XSV) profile calibration. Water depth (m), current velocity (cm sec-1) and direction (degrees) measured with ADCP at Site GeoB22732 (La Plata Terrace Moat), at Site GeoB22717 (Ewing Terrace Channel), and at Site GeoB22716 (Ewing Terrace Moat) for water depths greater than 500 m. Current directions: 0º=North; 90º=East; 180º=South and 270º=West.

Description: The data comprise PARASOUND profiles from the Ewing Terrace on the Argentine Continental Margin that were acquired during RV SONNE cruise SO260/1 in 2018. PARASOUND data was acquired using the hull-mounted parametric sub-bottom profiler PARASOUND P70 using a SLF frequency of 4 kHz and a non-rectangular pulse shape of ~0.25 ms length in quasi-equidistant mode. The trace envelope was computed for interpretation and visualization purposes.

Description: This data set include (1) the detailed petrographic description of the diagnostic rock types used to infer the source areas of the material recovered from the Mar del Plata Canyon area (Western South Atlantic at 38° S) at Sites GeoB13830, GeoB22712, GeoB22717 and L45; and (2) the Acoustic Doppler Current Profiler (ADCP) data obtained from Sites GeoB22716, GeoB22717 and GeoB22732. A variety of gravel- to cobble-sized rocks, recovered from the Mar del Plata Canyon area and interpreted as ice-rafted debris, represents the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub-Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. In the Mar del Plata Canyon, a combination of local slope instability and strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit. Microscopic petrograohic determinations were done on thin sections to identify the mineralogical composition of the rocks. During cruise SONNE SO260-1, the hull mounted Ocean Surveyor Teledyne RDI Acoustic Doppler Current Profiler (ADCP) with a doppler shift of 38 kHz provided real-time current velocity profiles over a range from 38 to 1,200 m water depth. ADCP data from the lowest 10-15 % of the water column have been removed due to possible scattering caused by strong seafloor echo. Doppler shifts were converted into current velocities using real water sound velocities by means of Conductivity-Temperature-Depth (CTD) and Expendable Sound Velocimeter (XSV) profile calibration. Detailed petrographic analysis on specific rock samples from the Mar del Plata Canyon area (SW Atlantic): sites GeoB13830, GeoB22712; GeoB22717 and L45

Description: The data comprise processed bathymetry and backscatter grids from the Ewing Terrace on the Argentine Continental Margin that were acquired during RV SONNE cruise SO260/1 in 2018. Bathymetric and backscatter data acquired using the 12 kHz Kongsberg EM122 echosounder were processed using the Open Source software MB-System. This includes navigation editing, interactive sound velocity corrections, erroneous beam flagging and grid generation. Backscatter grids of the recorded amplitude variations were created after normalizations using an angle varying gain (AVG) correction considering the seafloor morphology.

Description: The data comprise high-resolution multi-channel reflection seismic profiles from the Ewing Terrace on the Argentine Continental Margin that were acquired during RV SONNE cruise SO260/1 in 2018. Multichannel seismic data were acquired with a SERCEL Mini GI-Gun and GI-GUN with 0.2 l and 0.4 l volumes for generator and injector, respectively. For receiving the signal, a 96-channel analogue TELEDYNE streamer was deployed featuring varying channel spacing of 1 m to 4 m distance. Shot intervals varied between 4 to 6 seconds depending on the water depth, yielding shot spacing of ~10-15 m at a ship's speed of 5 to 5.5 kn. The sampling rate was set to 0.25 ms and the recording length varied between 3 and 4 seconds. The data were band-pass filtered, stacked and migrated with an emphasis on high resolution imaging and noise reduction. Velocity fields were picked interactively for NMO-correction and post-stack time migration. CMP bin distance was set to 2 m. Processing was conducted using the VISTA 2014 seismic data processing software.

Description: Multibeam bathymetry raw data using the ship's own Atlas Hydrographic Hydrosweep DS 2 multibeam echo sounder was not continuously recorded during RV METEOR cruise M37/1. Data was recorded on 15 days between 1996-12-05 and 1996-12-19. This dataset contains a survey North Atlantic Ocean mostly in the area around the Canary Islands. The approximate average depth is around 3800 m and ranges between 90m (min depth) and 13000m (unplausible max depth). The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. No ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus no SVP files are added to this dataset. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather bad to good since the gridded hillshade data showed relatively few obstacles in shallow waters and bad data in deeper areas. Data can be processed e.g. with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2022).