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  • Downcore variations in rock-magnetic properties of the sediments in core SK148/2 (A), and in AAS37/2 (B). ... Details of sediment cores used in this study ... The Rb, Sr, Sm and Nd concentrations in bulk samples and Sr–Nd isotopes of sediment at different intervals of cores 1 and 2 ... AMS 14C ages of the sediments in core 1 (SK148/2) ... X–Y plot of the Sr and Nd concentrations of sediment samples (core 1 and 2) together with the reported values of Fan sediments during the Pleistocene (A) and Holocene (B). (C) X–Y plot of Sr and Nd isotopes of core 1 and 2 (marked with dotted outlines) together with the reported values of the Fan sediments. Holocene sediments are shown in white background and those of Pleistocene age in grey background. ... Late Quaternary... Pelagic sediments
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  • Abstract: Independent proxies were assessed in two Late Quaternary sediment cores from the eastern South Atlantic to compare deep-water changes during the last 400 kyr. Two cores were recovered from beneath North Atlantic Deep Water (NADW) at approximately 3 000 m depth. Late Quaternary presence of NADW is indicated by the Cibicidoides wuellerstorfi assemblage on the Walvis Ridge (Core GeoB 1214) and the Bulimina alazanensis assemblage on the Namibian continental slope (Core GeoB 1710). The propagation of NADW is exclusively observed during interglacials, with maximum factor loadings in Stages 1, 5, 7, 9 and 11. These maxima are consistent with peaks in kaolinite/chlorite ratios and maxima of poorly crystalline smectite in the clay-mineral record. Kaolinite and poorly crystalline smectite are products of intense chemical weathering. They are injected into the NADW at low latitudes, north of the study area, and advected south. Chlorite, which is stable under cold weathering regimes, is a characteristic mineral of water masses of southern origin. During glacial stages, it is advected north with Southern Component Water (SCW). Above the NADW/SCW depths, kaolinite/chlorite ratios vary only slightly without a significant glacial-interglacial pattern, as measured in a core (GeoB 1712) from 1 000 m deep on the same profile of the Namibian continental slope off Walvis Bay. Category: geoscientificInformation Source: Supplement to: Gingele, Franz; Schmiedl, Gerhard (1999): Comparison of independant proxies on deep water advection in the southeast Atlantic off Namibia. South African Journal of Marine Science, 21, 181-190, https://doi.org/10.2989/025776199784126079 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: -23.431667 * LONGITUDE: 11.698333 * DATE/TIME: 1992-01-11T00:00:00 * ELEVATION: -2987.0 m * Recovery: 10.45 m * LOCATION: Namibia continental slope * CAMPAIGN: M20/2 * BASIS: Meteor (1986) * METHOD/DEVICE: Gravity corer (Kiel type) EVENT LABEL: * LATITUDE: -23.256667 * LONGITUDE: 12.808333 * DATE/TIME: 1992-01-12T00:00:00 * ELEVATION: -998.0 m * Recovery: 10.29 m * LOCATION: Namibia continental slope * CAMPAIGN: M20/2 * BASIS: Meteor (1986) * METHOD/DEVICE: Gravity corer (Kiel type)
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  • Down-core and Late Quaternary temporal variations in environmental magnetic and textural parameters of RG, MW, PN and PP cores. The vertical grey bands represent peat layers. ... The inter-magnetic ratios illustrating magnetic grain size show fluctuating nature, indicating multi-domain (MD) as well as SD grain size distributions (Fig. 4). The peat sediments generally show low χARM/SIRM values indicating a large MD component arising from the presence of detrital minerals, mostly its trend follows silt percent curve (Fig. 4). The transitions between magnetite and hematite tend to coincide with peat layers of the cores as indicated by SIRM/χ values (Fig. 4). For example, the peat sediments of RG and MW cores are characterized by such transition from magnetite to hematite in SIRM/χ values consistent with aridity changes between 9 ka and 7 ka.... Tectonic and geological setup of Krishna–Godavari basin (KG basin) along with locations of sampled areas in the inter-deltaic sediments at Kolleru Lake (after Biswas, 1993; Rode et al., 2010; Nageswara Rao et al., 2013). (a) Tectonic framework, and (b) Major geomorphological features within the KG basin. ... Summary of paleoclimatic, sea level and the tectonic events in the study area during the Late Quaternary period with their mineral magnetic and geochemical imprints. ... Down-core and Late Quaternary temporal variations in elemental concentrations of studied RG, MW, PN and PP cores. The vertical grey bands represent peat layers. ... Changes in terrigenous supply or source area have been inferred for Ganges–Brahmaputra river (Prakash Babu et al., 2010) by using additional concentration and grain size dependent magnetic parameters, although storage of terrigenous material in the delta during periods of sea level rise might have dominated the sediment record compared to climatically modulated riverine supply. The decreased S-ratio ca. core as indicated by reduction in χ, decrease in S-ratio, and constant elemental concentrations, hinting at an arid climatic regime between 9 ka and 8 ka (Figs. 4 and 5, Table 2). Hematite is most likely formed by LTO of magnetite/Ti-magentite in the catchment that experienced the driest conditions during the Early Holocene (Table 2). Colin et al. (1998) also suggested that aridity changes of the Ganges–Brahmaputra and Irrawaddy rivers conditioned the concentration and grain size of (titano)magnetite grains delivered by these rivers. Vaz and Banerjee (1997) had suggested that a drop in sea level fall during Little Ice Age (LIA) reduced the size and depth of the Pulicat lagoon. During this episode of sea level fall, the foreshore facies sand was diagenetically hardened and locally infiltrated by goethite. The Godavari region has experienced significant aridification as a consequence of weakening of the Indian monsoon over the Holocene (Ponton et al., 2012) and, therefore provides an excellent candidate for examining the relationships between climate and dynamics of terrestrial carbon discharge from the river drainage basin.... (a) The litho-stratigraphic sections of cores RG, MW, PN and PP. (b) Age depth model for RG, MW and PN sediment cores. ... Four cores, the details of which are given in Table 1, were collected from the inter-delta part of the KG delta around Kolleru Lake along the ECI in the state of Andhra Pradesh (Fig. 1). This delta formation started during the Late Carboniferous, resulting in deposition and preservation of an ∼8 km thick pile of sediments (Rao, 2001; Bastia and Nayak, 2006). Based on 210Pb and 230Th dating, a sedimentation rate of ∼20 cm/1000 y is suggested by Sarin et al. (1979). This basin contains multiple oil- and gas-bearing structures (Rao, 2001; Rode et al., 2010). The gas is thermogenic from Permian coals and shales (Khan et al., 2000). Godavari receives its sediments from a variety of geological formations, including Deccan traps of Late Cretaceous–Palaeocene age, Archaean granites and unclassified crystallines, regionally metamorphosed igneous and sedimentary rocks, Cuddapah and Proterozoic sediments, and Gondwana units. In the lower reaches, Godavari traverses the Eastern Ghats. The geological formations of the Krishna river basin include Deccan traps, Dharwars, Archaeans, Cuddapah–Kurnools, Khondalites, Charnockite, coastal Gondwana, and Cenozoic formations (Rengamannar and Pradhan, 1991). The adjoining region from where the cores have been collected displays Palakollu shale (Paleocene), Vadaparru shale (Eocene), Narasapur claystone (Oligocene), Rewa Formation (Mio-Pliocene) and smectite bearing Godavari clay (Holocene–Pleistocene).Table 1Borehole locations and the terminology adopted in the text along with the length of cores and their present altitude with respect to mean sea level.Borehole locationCodeLongitude (E)Latitude (N)Elevation (m, msl)Drilling depth (m)PedanindrakolanuPN81° 23′ 00.97″16° 43′ 40.58″+3.011.0MahileswaramuMW81° 08′ 27.18″16° 37′ 23.96″+3.112.5RamayyagudemRG81° 22′ 08.05″16° 38′ 48.26″+2.612.0PrattipaduPP81° 10′ 12.03″16° 32′ 44.77″+4.49.5
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  • Records of ice-rafted debris (IRD) from the Southern Ocean with the reference isotope curve of Howard and Prell (1994). Note the inconsistent signatures between the individual IRD records. The PS2547 record from the Amundsen Sea in the Pacific sector documents the dynamics of the west Antarctic ice sheet (Hillenbrand et al., 2002). The Scotia Sea record of PS2319 from the Atlantic sector was basically influenced by glacial dynamics on the Antarctic Peninsula (Diekmann et al., 2000, 2003). The PS1388 record from the Weddell Sea in the Atlantic sector indicates the dynamics of parts of the east Antarctic ice sheet and the calving behavior of icebergs during high stands of sea level (Grobe and Mackensen, 1992; Diekmann et al., 2003). The IRD abundances from the latter Polarstern sediment cores (PS) refer to the number of clasts >2mm in 1-kyr intervals. The ODP Site 1094 record is from the pelagic part of the Atlantic Southern Ocean and is displayed as the number of lithic grains in the medium to coarse sand fraction (0.125–2.00mm) per gram of sediment sample (Kanfoush et al., 2002). The Campbell IRD reference curve was obtained from the stacking of IRD records from various sediment cores in the pelagic western part of the Pacific sector (Carter et al., 2002), applying the same methodic approach as Kanfoush et al. (2002). The pelagic IRD records show a more integrated pattern of the Antarctic ice-sheet dynamics, possibly overprinted by sea-ice rafting and temperature effects that control the survival of icebergs and sea-ice. ... Glacial–interglacial variability of mass-accumulation rates of lithogenic matter (MARLitho) in the Southern Ocean with the reference isotope curve of Howard and Prell (1994) in comparison with the Vostok ice-core dust record (Petit et al., 1999). The PS2319 and PS1768 records are taken from Diekmann et al. (2003); the MD88-769 record was published by Bareille et al. (1994). Although the MARLitho patterns show strong affinities to dust deposition in Antarctica, the identification of clear dust signals in the Southern Ocean sediments remains unresolved. ... Southern Ocean with the frontal system of the Antarctic Circumpolar Current and the seasonal sea-ice limits (modified from Gersonde et al., 1999). Stars indicate the Vostok ice-coring location and the sites of the marine sediment records referred to in Figs. 3, 4, 6, and 7. ... Glacial–interglacial carbonate patterns of the Southern Ocean with the reference isotope curve of Howard and Prell (1994). The carbonate preservation index was derived from carbonate concentrations and dissolution indicators in sediment records from the Indian and Atlantic sectors of the Southern Ocean and seems to be representative for all sectors of the Southern Ocean (Howard and Prell, 1994). The carbonate record of ODP Site 1089 from a deep drift deposit of the southern Cape Basin shows an unusual regional carbonate signature with affinities to carbonate patterns of the low-latitude Pacific Ocean (Hodell et al., 2001). ... Lithology of modern sediments in the Southern Ocean, modified from Burckle et al. (1982). Here, it is modified with respect to the extension of the Circumpolar Opal Belt (biosiliceous oozes and muds) according to later publications (Burckle and Cirilli, 1987; McCoy, 1991; Zielinski and Gersonde, 1997; Bareille et al., 1998; Pudsey and Howe, 1998; Dezileau et al., 2000; Chase et al., 2003; Geibert et al., 2005). Note the qualitative character of the map, which is based on different methodic approaches. ... Terrigenous sediment
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  • Relative abundances of Cycladophora davisiana with assignments of C. davisiana stages in the investigated sediment cores and reference core RC11-120 (Hays et al., 1976). Stratigraphic correlations refer to the refined SPECMAP age model of core RC11-120 that is based on oxygen isotope and 14C stratigraphy (Howard and Prell, 1992). Arrows indicate sample depths and reservoir-corrected radiocarbon ages of the base-soluble organic sediment fraction (see Table 3). ... Idealized pattern of terrigenous sediment supply to the Scotia Sea during glacial and interglacial periods. Interglacial scenario, dominant interbasinal sediment transfer from the Weddell Sea, the southeastern Pacific Ocean and the Drake Passage through water-mass advection, scouring of pre-Quaternary sediments, and coastal erosion along the eastern Patagonian margin (see also Fig. 4.66 of Anderson, 1999). Low IRD input from overregional sources. Glacial Scenario: Expansion of terrestrial ice masses into the fjords and onto the shelves off western Patagonia and onto the shelves off the Antarctic Peninsula. High glaciogenic sediment discharge and bulldozing of shelf sediments. Sediments from these sources exhibit high magnetic susceptibility. Enhanced wind-driven Antarctic circumpolar current intensifies lateral sediment transport through water-mass advection. High IRD input from nearby sources during glacial to interglacial transitions, when grounded marine ice masses refloat and disintegrate (calving events). ... Mineralogical and geochemical data from the investigated sediment cores with correlation coefficients (r) between the compositional parameters and mass-specific magnetic susceptibility of the terrigenous sediment fraction (χMSterr)a ... Results of AMS-14C analyses on Corg samples from sediment core PS2515-3. SPECMAP ages were inferred from biofluctuation stratigraphy of Cycladophora davisiana ... Time series of mass-specific magnetic susceptibility of the terrigenous sediment fraction (χMSterr) and IRD fluxes in sediment cores PS2515-3 and PS2319-1 and climate proxies of the Vostok Ice Core from central East Antarctica (Petit et al., 1999). Changes in temperature are expressed as differences to the present local atmospheric temperature and are calculated from the deuterium and oxygen isotope record of the ice core. Dust values give the weight proportions of dust in ice. Note that the age model of the Vostok ice core, which refers to a glaciological time scale (GT4), does not necessarily correspond in all details to the SPECMAP ages presented for the sediment-core data. Especially the SPECMAP ages of MIS 2 more or less resemble 14C ages, while the Vostok ages approximate calendar years. ... sediment provenance
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  • Plant taxa identified in the palynological analysis of core D6 sediments (hscharacteristic lowland rain-forest tree taxa on Halmaherah and/or Serams (Monk et al., 1997)) ... Results of palynological analysis of D6 core sediments. All taxa are shown as a percentage of the total pollen sum except for those taxa that occur infrequently and with low values. For these, only their presence is indicated with dots. The shaded zone indicates the interval from 945 to 645cm that is devoid of pollen. ... δ13C (of bulk organic matter) vs. organic carbon content of selected samples (◊) D6 and D7 core samples (2.0–13.5m depth, see also Fig. 7; (■): recent deposits, 0–50cm depth). ... Results of radiocarbon dates of Holocene floodbasin deposits and beach shell in the Kao area, Halmahera (GrN: Groningen, The Netherlands). Groningen analysis (conventional 14C and δ13C) follows procedures described in Mook and Streurman (1983) and Mook and Van der Plassche (1986). Radiocarbon ages were calibrated to the bidecadal tree-ring/marine coral calibration curve using CALIB v. 4.2 (Stuiver and Reimer, 1993, 2000). Ages are calibrated in years B.P., and expressed as the median age (bold) and two sigma (95.4% confidence) ranges. The sequence of core D6 is discussed in the text. The locations of cores D6 and D7 are indicated in Fig. 5. Core D7 consists of a comparable sequence (11m in length) of fine-grained clastic–organic deposits, but with more, and compacted, woody peat levels. Sample locations of the Holocene coastal deposits are indicated in Fig. 3. Fig. 7D shows the typical beach deposit in location Pasang-1 ... Late Quaternary... Sedimentology and analytical data of Kao River plain sediments (core D6). Core samples were subsampled for texture, organic content and reconnaissance organic matter isotope analysis. Subsamples were freeze-dried and carefully homogenised. Texture was analysed in a Fritsch Laser particle sizer after pretreatment of bulk sample with 30% H2O2 (oxidation), boiling with 10% HCl (decalcification) and addition of dispersant (Na4P2O7·10H2O) (Konert and Vandenberghe, 1997). Organic carbon and nitrogen content of 20mg subsamples was determined after decalcification using a Carlo-Erba CNS analyser.
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  • Abstract: Analyses of terrigenous sediments from the Chilean continental slope off the southern border of the Atacama desert (27.5°S), focusing on illite crystallinity and the Fe:Al ratio of the sediments, reveal a high-frequency variability of the position of the Southern Westerlies, which is very similar to the coeval short-term climatic events known from Greenland ice cores and from North Atlantic sediments. Besides showing dominantly precession-driven variability in precipitation over the Andes, these analyses also reveal rapid changes in weathering intensity along the Chilean Coastal Range during the last 80,000 years. These rapid changes occur at much shorter timescales than the 19-100 kyr orbital forcing of the Milankovitch cycles. Category: geoscientificInformation Source: Supplement to: Lamy, Frank; Klump, Jens; Hebbeln, Dierk; Wefer, Gerold (2000): Late Quaternary rapid climate change in northern Chile. Terra Nova, 12, 8-13, https://doi.org/10.1046/j.1365-3121.2000.00265.x Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: -27.466667 * LONGITUDE: -71.251667 * DATE/TIME: 1995-06-07T00:00:00 * ELEVATION: -1947.0 m * Recovery: 4.89 m * LOCATION: South-East Pacific * CAMPAIGN: SO102/2 * BASIS: Sonne * METHOD|DEVICE: Gravity corer (Kiel type)
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  • Downcore variability of Sr and Nd isotope ratios in the sediments of Core DGKS9604. ... Comparison of Sr and Nd isotopes between Core DGKS9604 sediments and the potential end-members. ... Downcore variability of main and trace elemental concentrations in the sediments of Core DGKS9604. ... AMS 14C ages and sedimentation rates measured in Core DGKS9604. ... Concentrations of Sr and Nd and Sr–Nd isotopic ratios of Core DGKS9604 sediments in the middle Okinawa Trough. ... Sediment provenance... Late Quaternary
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  • Distribution of total coccoliths/g sediment and relative abundance of the most common species in surface sediments from the equatorial Atlantic. The grey shadings indicate higher phytoplankton pigment concentrations (>0.4mg/m3) recorded by the Coastal Zone Color Scanner (CZCS) from 1979 to 1986. ... Location of surface sediment samples, total number of coccoliths/g sediment and abundance of the most common species ... Total number of coccoliths/g sediment, coccolith accumulation rates and abundance of most common species from cores GeoB 1117-2 and GeoB 1523-1 ... Location of surface sediment samples (dots) and position of sediment cores GeoB 1117-2 and GeoB 1523-1 (open squares). Positions are given in Table 3. ... Numbers of 109 coccoliths/g sediment (dashed line) and coccolith accumulation rates (AR coccoliths) (solid line) in core GeoB 1117-2 (upper panel) and GeoB 1523-1 (lower panel). Shading and numbering as in Fig. 7. ... Late Quaternary
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  • Humification analyses (BSAT03) and Ti counts (BSAT02). Residuals for both proxies are illustrated over the spliced x-radiograph profile of the laminated organic sediments. ... Age–depth, stratigraphy and core correlation for Bromfield Swamp. Constructed from 34 radiocarbon dates using Bacon 2.2 and the SHCal13 calibration data set. The P-sequence (1, 1) age–depth model applies Bayesian modelling. The optical image of core BSAT03 is a diagrammatic representation only, constructed from composite ITRAX core scans of BSAT01/BSAT02. The stratigraphy is constructed from sediment description and grain size analysis; correlation of sediment cores determined from individual magnetic susceptibility (κ) profiles for BSAT02/BSAT03. ... Late Quaternary... Lithostratigraphy (layers and units) for BSAT01–03. Unit depths are shown for long-core BSAT03, extracted near the centre of Bromfield Swamp. Cores BSAT01–02, extracted nearer the Swamp boundary, show a 0.25m foreshortening of the gyttja profile; consequently, to correlate units across all three cores, an additional 0.25m must be added to all unit depths below the peat profiles in cores BSAT01–02. (See Section 4.2 for details). ... ITRAX Compilation for BSAT02 (3.00–8.46m). Optical and X-radiographic images of 1m sediment core sections and profiles of magnetic susceptibility, organic content and major and trace elements are plotted against depth (mm). Depths referred to in text are corrected to depths in core BSAT03. (Bromine not illustrated; see Fig. 8). ... Bromfield Swamp, eastern sector. Measuring 1.0km×0.8km, the swamp occupies the base of a large maar. Core BSAT03, used for geochronology, taken in open water from a small embayment (site marked with cross). Cores BSAT01 and BSAT02 taken in open water approximately 20m east (left) of BSAT03 core site.
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