ALBERT

Description: This dataset contains 40Ar/39Ar bedrock ages measured from 20 hornblende, 9 biotite, and 40 muscovite grains collected from the Marsyangdi valley of central Nepal. The samples were all collected from medium to high-grade metamorphic rocks, to add to already available thermochronometric datasets in the region, and better constrain the exhumation history of the central Himalayas. Measurement of the hornblende and biotite ages were performed using a step-heating method. However, measurement of the muscovite ages was performed using either a step-heating, or a total fusion method.

Description: The Antarctic Digital Magnetic Anomaly Project (ADMAP) is an Expert Group of the Scientific Committee on Antarctic Research (SCAR). ADMAP compiles and publishes compilations of near surface magnetic anomaly data south of 60°S. Its two most recent compilations are referred to as ADMAP2B and ADMAP2S. ADMAP2B shows near-surface data only, with large gaps. ADMAP2S fills the gaps with satellite-derived data. Both products are freely available, but until now only for proprietary and/or custom software and with a custom map projection that is not widely used outside of the group. This contribution offers both ADMAP2B and ADMAP2S gridded data products in the widely used geotiff, netcdf, and kmz grid formats, and projected into the well known geodetic longitude-latitude and SCAR's recommended WGS-84 Antarctic Polar Stereographic system. These grids are suitable for use in a wide range of applications, including the widely-used free and open source products QGIS, Generic Mapping Tools, and Google Earth.

Description: The samples have been collected with R/V Polarstern during PS109 between September and October 2017. Sediment was collected with a camera-equipped MUC (TV-MUC; diameter of 93mm; circle area 0.007 m2) or with a benthic lander (dimensions 20 cmx20 cm; square area 0.04 m²), sliced into 0-5 cm and 5-10 cm layers and subsequently sieved over a 500 µm mesh. Afterwards, the samples were fixed with 4 % seawater-buffered formaldehyde in Kautex bottles at room temperature. In the lab, samples were stained with Rose Bengal and macrofauna and foraminifera individuals were identified to the lowest taxonomic level possible, and the blotted wet formalin weight of macrofauna individuals was measured with a precision balance (DeltaRange XP56 or AX205; Mettler Toledo, Ohio, USA).

Description: This dataset, titled the Arctic Boreal Burned Area (ABBA) product, provides annual cumulative end-of-season burned area in circumpolar boreal forests and tundra at 463 m for the years 2002-2022. The data were generated based on data inputs collected by NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instruments using an algorithm developed by Loboda et al. (2011). Because this algorithm is specific to the high northern latitude (HNL) regions (i.e., it takes into account various conditions that are unique to the HNL), ABBA maps burned areas more accurately than other counterparts at this resolution.

Description: The stable silicon isotopic composition of siliceous sponge skeletal elements, spicules, is a potential archive of past dissolved silicon (silicic acid, or DSi) concentrations in bottom waters. Several field-based studies have shown that there is a non-linear relationship between the concentration of ambient DSi and both the isotopic composition (denoted by d30Si) of spicules and apparent isotopic fractionation by sponges during growth. There is considerable scatter in the calibration, with some studies highlighting variation within an individual sponge, and between individuals in both monospecific and more diverse populations. When reconstructing past DSi, it is only possible to differentiate spicules by their morphology, which in many cases will not be taxonomically diagnostic. However, there has yet to be a systematic study of core top and downcore d30Si measurements from different spicule types. Here we address that gap using spicules extracted from two shallow sediment cores from the Schultz Massif Seamount between the Norwegian and Greenland Seas collected on R/V G.O.Sars expedition GS2016109A. Sediments were sliced at 1cm intervals, washed and dried, and spicules hand-picked out and sorted by morphological type. The spicules were dissolved and analysed for silicon isotopic composition using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS).

Description: This is an update of and extension of the MARGO compilation of planktonic foraminifera assemblages for the Last Glacial Maximum (19,000-23,000 ka BP). It includes all data previously compiled within the MARGO project, with some minor corrections (indicated in QCNote), data published since and new counts. The taxonomy has been updated and harmonised to be directly comparable with the ForCenS core top data set (https://doi.pangaea.de/10.1594/PANGAEA.873570; https://doi.org/10.1038/sdata.2017.109). Criteria for inclusion of new data followed those of MARGO, including the ranking of chronological confidence (https://doi.org/10.1016/j.quascirev.2004.07.017). All data pertain to the size fraction 〉150 µm. Absolute counts are provided whenever these were available; no attempt has been made to correct published relative abundance data when their sum deviated from unity. The data are made available in wide format with metadata with self-explainable headers.

Description: These bundled biogeochemical data of sediment core EN20001, from Lake Khamra (59.99095° N, 112.98345° E), in SW Yakutia consist of four datasets: (1) Radiocarbon age dating of bulk sediments from sediment core EN20001 from Lake Khamra, measured at AWI MICADAS; (2) Element composition of the sediment core EN20001 from Lake Khamra, measured at the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR); (3) TOC and TN of the sediment core EN20001 from Lake Khamra, measured in the sediment laboratory at AWI, Potsdam; (4) Pollen and non-pollen palynomorphs of the sediment core EN20001 from Lake Khamra, measured at AWI, Potsdam. This study was additionally supported by a short-term grant (not numbered) from AWI Graduate School (POLMAR), and PhD Completion Scholarship (not numbered) provided by University of Potsdam.

Description: Here we document the stable isotope (δ18O and δ13C) from the shells of planktic foraminifer Globorotaloides hexagonus from Eastern Equatorial Pacific core site TR163-23 (0° 24.6' N, 92° 9.6' W; 2,730 m depth). Morphometric measurements include the length of the shell along the longest dimension from the final chamber, the number of chambers in the final whorl, and porosity. Porosity was assessed by the percentage of surface area on the final chamber consisting of pores. Stable isotope analyses were carried out on pooled samples of 3-10 shells, while morphometrics were measured in individuals.

Description: The main purpose of this work is to establish the formation time of Holocene syngenetic ice wedges that have been exposed on the coast of Baydarata Bay near the village of Yarynskaya, 500 m to the southeast from the mouth of the Ngarka-Tambyakha River.Radiocarbon dating of microinclusions of organic matter, extracted directly from three Holocene syngenetic ice wedges, was conducted using accelerator mass spectrometry (AMS). The dating of the wedges correlates to their formation approximately 6.4, 5.0, and 1.9 cal ka BP. A comparison of the oxygen isotopic composition of the Holocene ice wedges (in which the δ18О values vary mainly from -21.8 to -13.73%) and modern ice wedges (the age of which, as a rule, does not exceed 100 years) showed a close range of variations in values. According to isotope oxygen data, the average January air paleotemperature in the Middle and Late Holocene at the coast of the Baydarata Bay was calculated. It is shown that the average January air temperature during this period here varied from about -20 to -25 °C, however, during milder winters it could be about -18 °C. Ice samples were collected from ice wedges along the vertical profile every 10 cm using Makita DDF481rte 18B and Bosch GSR 36 VE-2-LI drills with steel ice crowns with a diameter of 51 mm. Measurements of the oxygen isotopic compositions in ice were performed on a Picarro L 2130-i laser infrared spectrometer at the Center for X-ray Diffraction Studies at the Research Park of St. Petersburg State University (XRD Center SPbU). The following international standards were used: V-SMOW-2, GISP, SLAP, USGS-45, and USGS-46. The measurement errors were ±0.02‰ for δ18O. In total, 63 samples of ice wedges were analyzed.