ALBERT

Description: Analytical challenges in obtaining high quality measurements of rare earth elements (REEs) from small pore fluid volumes have limited the application of REEs as deep fluid geochemical tracers. Using a recently developed analytical technique, we analyzed REEs from pore fluids collected from Sites U1325 and U1329, drilled on the northern Cascadia margin during the Integrated Ocean Drilling Program (IODP) Expedition 311, to investigate the REE behavior during diagenesis and their utility as tracers of deep fluid migration. These sites were selected because they represent contrasting settings on an accretionary margin: a ponded basin at the toe of the margin, and the landward Tofino Basin near the shelf's edge. REE concentrations of pore fluid in the methanogenic zone at Sites U1325 and U1329 correlate positively with concentrations of dissolved organic carbon (DOC) and alkalinity. Fractionations across the REE series are driven by preferential complexation of the heavy REEs. Simultaneous enrichment of diagenetic indicators (DOC and alkalinity) and of REEs (in particular the heavy elements Ho to Lu), suggests that the heavy REEs are released during particulate organic carbon (POC) degradation and are subsequently chelated by DOC. REE concentrations are greater at Site U1325, a site where shorter residence times of POC in sulfate-bearing redox zones may enhance REE burial efficiency within sulfidic and methanogenic sediment zones where REE release ensues. Cross-plots of La concentrations versus Cl, Li and Sr delineate a distinct field for the deep fluids (z 〉 75 mbsf) at Site U1329, and indicate the presence of a fluid not observed at the other sites drilled on the Cascadia margin. Changes in REE patterns, the presence of a positive Eu anomaly, and other available geochemical data for this site suggest a complex hydrology and possible interaction with the igneous Crescent Terrane, located east of the drilled transect.

Description: The hydrography of the Indian‐Atlantic Ocean gateway has been connected to high‐latitude climate dynamics by oceanic and atmospheric teleconnections on orbital and suborbital timescales. A wealth of sedimentary records aiming at reconstructing the late Pleistocene paleoceanography around the southern African continent has been devoted to understanding these linkages. Most of the records are, however, clustered close to the southern South African tip, with comparatively less attention devoted to areas under the direct influence of frontal zones of the Southern Ocean/South Atlantic. Here we present data of the composition and concentration of the diatom assemblage together with bulk biogenic content and the alkenone‐based sea surface temperature (SST) variations for the past 350 kyr in the marine sediment core MD02‐2588 (approximately 41°S, 26°E) recovered from the southern Agulhas Plateau. Variations in biosiliceous productivity show a varying degree of coupling with Southern Hemisphere paleoclimate records following a glacial‐interglacial cyclicity. Ecologically well‐constrained groups of diatoms record the glacial‐interglacial changes in water masses dynamics, nutrient availability, and stratification of the upper ocean. The good match between the glacial maxima of total diatoms concentration, Chaetoceros spores abundance, and opal content with the maximum seasonal cover of Antarctic ice and the atmospheric dust records points to a dominant Southern Hemisphere forcing of diatom production. Suborbital variability of SST suggests rapid latitudinal migrations of the Subtropical Front and associated water masses over the southern Agulhas Plateau, following millennial contractions and expansions of the subtropical gyres. Warmings of the upper ocean over site MD02‐2588 during terminations IV to I occurred earlier than that in the Antarctic Vostok, which is indicative of a Northern Hemisphere lead. Our multiparameter reconstruction highlights how high‐latitude atmospheric and hydrographic processes modulated orbital highs and lows in primary production and SST as triggered by northward transport of Si, eolian dust input, and latitudinal migrations of frontal zones.

Description: Here we represent pore water, headspace gas, and TOC data from the four cores recovered from the Chukchi Sea by Jumbo Piston Corer (JPC) during the ARA06C Expedition in 2015 to investigate the origin and diagenesis of pore water and gas. The study cores were retrieved from the Chukchi Sea Shelf (ARA06C-JPC01), the Northwind Basin (ARA06C-JPC02), the East Siberia Continental Slope (ARA06C-JPC03), and the Chukchi Basin (ARA06C-JPC04). We collected pore water from Site ARA06C-JPC01, ARA06C-JPC02, ARA06C-JPC03, and ARA06C-JPC04 and performed compositional and isotopic analyses (e.g. major cation and anions, oxygen, and deuterium isotope, carbon-13 isotope of dissolved carbon, 87Sr/86Sr). The analyzed results of pore water were displayed in the PW Table. The compositional and isotopic data of headspace gas (e.g. methane concentration, and carbon-13 isotope of methane and carbon dioxide) from Site ARA06C-JPC01, ARA06C-JPC02, ARA06C-JPC03, and ARA06C-JPC04 as well as TOC content of bulk sediment from Site ARA06C-JPC01, were represented in the HS Table and TOC Table, respectively.

Description: Cl- and alkalinity were determined by visual titration with 0.1 M AgNO~3~ and 0.02 M HCl, respectively. NH~4~+ and PO~4~3 were measured spectrophotometrically (UV-2450, Shimazu) at 640 and 885 nm, respectively. Sulfate (SO~4~2-) was analyzed by an ion chromatography (ICS-1500, Dionex) in the Korea Institute of Geoscience and Mineral Resources (KIGAM). Major and minor cations (Na^, K, Mg^2+, Ca^2+, Ba^2+, B, Sr^2+^, and H~4~SiO~4~) were analyzed by an inductively coupled plasma-optical emission spectrometer (Optima 8300 ICP-OES, Perkin Elmer) in the Korea Basic Sciences Institute (KBSI). δ^18^O~H2O~ and δD~H2O~ were determined with a wavelength-scanned cavity ring-down spectroscopy (L2120-i, Picarro Inc.) in the KIGAM. δ^13^C~DIC~ was analyzed with a Finnigan DELTA-Plus mass spectrometer using a Gas-Bench II automated sampler at Oregon State University. 87^Sr/^86^Sr ratio was measured using a Neptune multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS, Thermo Scientific) in the KBSI. The δ^11^B signatures were analyzed with a Neptune MC-ICP-MS in the St. Andrews Isotope Geochemistry Laboratory.