ALBERT

Description: Lateglacial/early Holocene interval from the sediment core JM09-020GC recovered in Storfjordrenna (western Barents Sea) has been studied for benthic foraminifera assemblages, stable isotopes, IRD, vivianite microconcretions, magnetic susceptibility, and elemental composition in order to identify the causes and mechanisms of abrupt climate change during the Younger Dryas. The core was retrieved with R/V Jan Mayen (University of Tromsø – The Arctic University of Norway, UiT) in November 2009 from the Storfjordrenna (76°31489' N, 19°69957' E) at a bottom depth of 253 m. Prior to sediment core opening, the magnetic susceptibility was measured using a loop sensor installed on a GEOTEK Multi Sensor Core Logger at the Department of Geology, UiT. Core sections were stored in the laboratory for one day prior to measurements, thus allowing the sediments to adjust to room temperature and avoiding measurement errors related to temperature changes (Weber et al., 1997). Qualitative element-geochemical measurements were performed with Avaatech X-ray fluorescence (XRF) core scanner using the following settings: 10 kV, 1000 µA, 10-s measuring time, and no filter. Sediment samples for foraminiferal and vivianite analyses were freeze-dried, weighed, and wet sieved using sieves with mesh sizes of 500 µm and 100 µm. The residues were dried, weighed again, and subsequently split on a dry micro-splitter. Where possible, at least 300 specimens of foraminifera were counted in every 1 cm of sediment. Species identification under a binocular microscope (Nikon SMZ1500) was supported using the classification of Loeblich and Tappan (1987), with few exceptions, and percentages of the eight indicator species were applied. The benthic foraminiferal abundance and ice-rafted debris (IRD; grains 〉500 µm) were counted under a stereo-microscope and expressed as flux values (number of specimens/grains cm-2 ka-1) using the bulk sediment density and sediment accumulation rate.

Description: A gas inlet was installed at the bow of RV Poseidon. Atmospheric gas concentrations of CH4 and CO2 were measured continuously with a Picarro G2301-f analyzer.

Description: Porewater analyses from all M157 multicores and gravity cores are presented here. For each site, both shipboard and shore-based analyses are included. Shipboard analyses include photometric determination dissolved iron (Fe2+) and phosphate (PO43-) (Hach Lange DR 5000 photometer, 565 nm and 880 nm wavelengths), as well as ammonium (NH4+) via flow injection gas separator technique. Additional porewater aliquots were collected for analyses at MARUM between December 2019 and February 2020. Shore-based analyses completed in the Sediment Geochemistry Laboratory at MARUM include: ion chromatography (F-, Br-, Cl-, SO42-, NO3-, and PO43-), photometric determination of sulfide (wavelength 670 nm), DIC and NPOC (Analytik Jena Multi N/C Series), and inductively coupled plasma emission spectrometry (Al, B, Ba, Ca, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, S, Si, Sr, Ti, V). All data is over-specified for calculation purposes. Several constituents were below detection and therefore not reported here. These include: IC determined NO3-, and PO43- , ICP measurements of Cr, Cu, Mo, No, and V. Both depth in core (cm) and a corrected depth below seafloor (cm) are presented. Gravity core depths were adjusted to extend the porewater profiles from the paired multicore from the site. This offset was determined visually, based on eight constituent profiles. Most gravity cores were offset only by the length of the multicore, except for Site 14 with an additional 5cm, and Site 34 which an additional 10 cm was needed. Sites 10, 48 and 44 are only multicores, while Site 47 is only a gravity core. The data from site 48 was used to estimate an offset for the Site 47 gravity core due to their proximity.

Description: The Indian Summer Monsoon (ISM) with its rainfall is the lifeline for people living on the Indian subcontinent today and possibly was the driver of the rise and fall of early agricultural societies in the past. Intensity and position of the ISM have shifted in response to orbitally forced thermal land-ocean contrasts. At the northwestern monsoon margins, interactions between the subtropical westerly jet (STWJ) and the ISM constitute a tipping element in the Earth's climate system, because their non-linear interaction may be a first-order influence on rainfall. We reconstructed marine sea surface temperature (SST), supply of terrestrial material and vegetation changes from a very well-dated sediment core from the northern Arabian Sea to reconstruct the STWJ-ISM interaction. The Holocene record (from 11,000 years) shows a distinct, but gradual, southward displacement of the ISM in the Early to Mid-Holocene, increasingly punctuated by phases of intensified STWJ events that are coeval with interruptions of North Atlantic overturning circulation (Bond events). Effects of the non-linear interactions culminate between 4.6-3 ka BP, marking a climatic transition period during which the ISM shifted southwards and the influence of SWTJ became prominent. The lithogenic input shows an up to 4-fold increase after this time period signaling the strengthened influence of agricultural activities of the Indus civilization with enhanced erosion of soils amplifying the impact of Bond events and adding to the marine sedimentation rates adjacent to the continent.

Description: During RV Maria S. Merian cruise MSM67 refraction and wide-angle reflection seismic data were acquired. We present seismic record sections (.sgy format) of ocean bottom seismometer components from thirty stations along the W-E oriented seismic profile MSM67-P01, which is situated at the Jan Mayen Ridge. The profile stretches over a distance of 266 km and was shot using an airgun array of six G-gun clusters with a total volume of 50 l at 140 bar. A total of 2226 shots were fired at a distance of ~110 m with an airgun towed behind the vessel in a depth of 8 m. Data are unprocessed, however, they are corrected for instrument drift along the profile using the symmetry of the direct arrival and the data are time corrected.