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  • Abstract: The origin of the massive ice is important for understanding the Quaternary history of the Yamal region and to predict the occurrence of massive ice, which is important for gas exploration and the development of infrastructure. Massive ice bodies occur in the Bovanenkovo gas field area within sediments such as layers, laccoliths, rods and lenses. Maximal thickness of the tabular ice is 28,5 m; mean thickness is about 8 m. Deposits of the third terrace underlying and overlapping the tabular ice had been formed from 25 ka BP to 20 ka BP, according to ¹⁴C dates. Oxygen-isotope values (δ¹⁸O) of massive ices are ranged from 12, 49‰ up to -22, 95‰. Deuterium (²H) values vary from -91, 7‰ up to -177, 1‰. Deuterium excess (dexc) changes from 3, 4 to 10, 6‰. Both homogenous and contrast distribution δ¹⁸O and (²H) vs. depths in massive ice bodies evidences the segregated and/or infiltrated-segregated manner of ice formation. Pollen, spores and algae spectra from ice are similar to pollen characteristics of modern lacustrine and coastal floodplain sediments in the area. The ingression of cold seawaters on a coastal flood plain caused freezing and ice segregation, with the formation of extensive ice layers under the large but shallow lakes. As a result, syngenetic and genetically heterogeneous ice, such as: segregated, infiltrated-segregated, lake bottom congelation ice etc. was formed. Category: geoscientificInformation Source: Not Available Supplemental Information: Data was submitted and proofread by Yurij K Vasil'chuk and Lyubov Bludushkina at the faculty of Geography, department of Geochemistry of Landscapes and Geography of Soils, Lomonosov Moscow State University. Coverage: Not Available
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  • Abstract: To assess the impacts of Amazon River discharge, Saharan dust deposition, N2‐fixation and mixed‐layer deepening on the biological carbon pump, sediment traps were moored from October 2012 to November 2013 at two sites in the western tropical North Atlantic (49°W,12°N/57°W,12°N). Particle exports interpreted along with satellite‐ and Argo‐float data show peak fluxes in biogenic silica (31 mg m**−2 d**−1) and organic carbon (25 mg m**−2 d**−1) during the fall of 2013 that were ten to five times higher than any time earlier during the year. These high export fluxes occurred in tandem with high surface chlorophyll a concentrations associated with the dispersal of the Amazon River plume, following retroflection into the North‐Atlantic‐Counter‐Current. High fucoxanthin fluxes (> 80 μ g m**−2 d**−1) and low δ15N‐values (−0.6‰) suggest a large contribution by marine diatom‐diazotrophic‐associations, possibly enhanced by wet Saharan dust deposition. During summer, the Amazon River plume resulted in high mass fluxes at 57°W that were enriched in biogenic silica but weakly influenced by diazotrophic‐associations compared to the fall event at 49°W. High carbonate‐carbon fluxes (17 mg m**−2 d**−1) dominated a second single event at 49°W during spring that was likely triggered by mixed‐layer deepening. Rain‐ratios of BSi/Ccarb amounted to 1.7 when associated with high export fluxes linked to the Amazon River plume. Compared to an annual average of 0.3, this indicates a more efficient uptake of CO2 via the biological pump compared to when the plume was absent, hence supporting earlier observations that the Amazon River plume is important for ocean CO2 sequestration. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Grasslands cover 41.7% of China's land surface and distribute mainly in NW China. To project future change of grassland fires, it is essential to explore paleofire dynamics. However, comparatively little is known about the patterns and driving forces of grassland fires in NW China due to the scarcity of paleorecords. Here, we present Holocene sedimentary records of grassland fire and vegetation in westerly-dominated Xinjiang (NW China) to examine fire-fuel-climate interactions. We find that grassland fire-regime is fuel-limited, consistent with other grasslands worldwide. We reveal that burning increased throughout the Holocene, due to increasing moisture, grass cover, fuel load and temperature of spring fire season. The Holocene pattern of burning coincides with several other records nearby and a global-scale grassland fire record. Our results are different from monsoonal China where fuel load is not a constraining factor and more (less) fires occurred during colder/drier (warmer/moister) periods in the Holocene. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 44.970000 * LONGITUDE: 128.801100 * ELEVATION: 1300.0 m * Recovery: 126.75 cm * LOCATION: Wenquan County, Xinjiang Province, Northwest China * METHOD/DEVICE: Drilling/drill rig
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  • Abstract: A palaeomagnetic study of 160 discrete samples from an archaeological excavation near Piatra Neamt (Romania) gave the opportunity to establish the palaeomagnetic signal from this sequence. We correlated the relative palaeointensity record obtained from the Poiana Cireşului site to reference data, discuss our correlation and the possibility of indirect dating of (archaeology bearing) loess by the way of palaeomagnetic intensity signal comparison. Within the palaeomagnetic record we find seveal low intensity intervald, possibly related to geomagnetic excursions. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 46.916670 * LONGITUDE: 26.316670 * LOCATION: Romania * METHOD/DEVICE: Outcrop sample
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  • Abstract: The Intertropical Convergence Zone (ITCZ), which is the heaviest rain belt on Earth, significantly influences global hydroclimate change and livelihood of nearly 40% of the global population. However, long-term precipitation records are sparse from the Indo-Pacific region, especially from the southern margin of the Indo-Pacific ITCZ, restricting our understanding of the overall natural variability of the ITCZ in the past. In this study, we present a new summer monsoonal precipitation record that spans the last 410 kyr from the southern margin of the Indo-Pacific ITCZ, based on the logarithmic ratio between terrigenous fraction K and pelagic fraction Ca (ln(K/Ca)). Contents of the both elements were derived from X-ray fluorescence scanning on sediment cores from Site U1483 (13°05.24′ S, 121°48.25′ E, water depth 1733 m) that was drilled offshore northwestern Australia during International Ocean Discovery Program Expedition 363. Comparison of the new precipitation record with published precipitation records from the northern margin and meteorological centre of the Indo-Pacific ITCZ shows that precipitation changed nearly in phase between the hemispheres on the precession band, possibly linked to expansion and contraction in the latitudinal extent of the Indo-Pacific ITCZ. In contrast, interhemispheric precipitation was nearly in anti-phase on the obliquity band, likely due to latitudinal migration of the Indo-Pacific ITCZ. Our findings imply that tropical hydroclimate cycles were regulated by the orbital forcing but with significantly different response to changes of the ITCZ on precession and obliquity bands. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Biển Hồ lake (14°03'03.5″ N, 108°00'00.2″ E) is a volcanic crater (i.e. maar) in Vietnam's Central Highlands that has been accumulating sediment since the Pleistocene. Here we show data from our bathymetric surveys and physical, chemical and diatom analyses of the uppermost sediment (0-2 m) (NAFOSTED project 105.99-2018.316). The data document environmental history recorded over the last 70 years in Biển Hồ Maar sediment and provide an empirical basis for the interpretation of Biển Hồ's deeper Holocene and pre-Holocene sedimentary record. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Core M1-Afrom Mljet Island, Croatia, was retrieved from a submerged sinkhole to investigate tephra and reconstruct past sea levels. Eleven tephra layers were found, out of which six are macroscopically visible, while five are cryptotephra. For two of the tephra layers, glass shard concentrations were below the critical amount necessary for reliable analysis, while two more originated from a stratigraphical interval likely disturbed by drilling operations. Major and trace element compositions of glass shards were determined by wavelength dispersive spectroscopy(WDS) using an electron microprobe analyser (EMPA) and by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The tephra discrimination relied on a novel approach based on a multivariate analysis of element selection and the use of log-ratio scatterplots and common bivariate plots. The results enabled correlation of five tephra to known eruptions originating from Somma-Vesuvius and Campi Flegrei. Specifically,we identified Avellino Pumice, Mercato, Agnano Monte Spina and Neapolitan Yellow Tuff, extending known distributions for Avellino and Agnano Monte Spina. Moreover, our findings possibly support an earlier proposition that Agnano Monte Spina tephra originated from two eruptions with a pause of a few decades in between. Based on the tephra correlations and radiocarbon dating, an age-depth model was compiled that provided chronological constraints for the sea level during the formation of the lake (10.7 cal. ka BP, 49 m b.s.l.) and sea intrusion (2.3 cal. ka BP, 2.5 m b.s.l.). Category: geoscientificInformation Source: Not Available Supplemental Information: Project: 1. Lost Lake Landscapes of the Eastern Adriatic Shelf (LoLADRIA), Grant number (HRZZ-IP-2013-11-9419) 2. FUcino Tephrochronology Unites Quaternary Records (FUTURE), Grant number (20177TKBXZ_003I) Coverage: Not Available
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  • Abstract: 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. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 76.314890 * LONGITUDE: 19.699570 * ELEVATION: -253.0 m * CAMPAIGN: JM09702 * BASIS: Jan Mayen * METHOD/DEVICE: Gravity corer
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  • Abstract: Major element and trace element geochemical data from tholeiitic basaltic volcanic and volcaniclastic rocks from the Riverton Peninsula and Colac Bay, Southland, New Zealand. These rocks form part of the Permian Brook Street Terrane. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: It contains three tables that correspond to the supplementary information of the article mentioned above. Tables S1 and S2 can be found within the Supplementary Information document. Table S3 contains the characteristic remanent magnetisation (ChRM) directions (with associated sample position and confidence angle) used for the magnetostratigraphic correlation. Table S4 lists the calcareous nannofossil abundance for each rock sample expressed in number of specimens per squared millimetre. Table S5 is the foraminifera distribution chart. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
    Data Types:
    • Tabular Data
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