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Journal of Quaternary Science
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Abstract: The pollen record of three marine late Quaternary cores off Senegal shows a juxtaposition of Mediterranean, Northern Saharan, Central Saharan elements, which are considered transported by the trade winds from a winter-rainfall area, and Sahelian, Soudanese, Soudano-Guinean elements, considered transported both by winds and mostly by the Senegal River, and coming from the monsoonal, summer tropical rainfall area of southern West Africa. Littoral vegetation is either the edaphically dry and saline Chenopodiaceae from sebkhas at the time of the main regression, or the warm tropical humid mangrove with Rhizophora during the humid optimum period. Four stratigraphic zones reflect, from basis to top: Zone 4. A semi-arid period with a balanced pollen input. Zone 3. A very arid period with the disappearance of monsoonal pollen, probably from the disappearance of the Senegal River, a very saline littoral plain with Chenopodiaceae, a larger input of northern Saharan pollen from intensified trade winds. Zone 2. A quite humid period, much more so than today, very suddenly established, with a northward extension of the monsoonal areas, a rich littoral mangrove, and weakening of the trade winds. Zone l. A slow and steady evolution toward the present semi-humid conditions with regression of the mangrove, and of the monsoonal areas toward the south. Tentative datations and correlations with the Tchad area suggested: zone 4: 22,500 to 19,000 years BP; zone 3: 19,000 to 12,500 years BP; zone 2: 12,500 to 5,500 years BP; zone 1: 5,500 years BP to top of core. Dinoflagellate cysts display a tropical assemblage with mostly estuarine neritic elements and also a weak oceanic component, mostly in the lower slope core 47. Cosmopolitan taxa dominate the assemblage and only a few species point to more specialized environments. Quantitative variations of the assemblage are the basis of stratigraphy which is not similar to the pollen stratigraphy, and an inshore-outshore gradient has to be taken into account to correlate the three cores. Category: geoscientificInformation Source: Supplement to: Rossignol-Strick, Martine; Duzer, Daniele (1979): Late Quaternary pollen and dinoflagellate cysts in marine cores off West Africa. Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C30, 1-14 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 15.443333 * LONGITUDE: -17.306667 * DATE/TIME: 1971-01-01T00:00:00 * ELEVATION: -625.0 m * LOCATION: East Atlantic * CAMPAIGN: M25 * BASIS: Meteor (1964) * METHOD|DEVICE: Kasten corer EVENT LABEL: * LATITUDE: 15.480000 * LONGITUDE: -17.360000 * DATE/TIME: 1971-11-17T00:00:00 * ELEVATION: -945.0 m * Recovery: 5.5 m * LOCATION: East Atlantic * CAMPAIGN: M25 * BASIS: Meteor (1964) * METHOD|DEVICE: Kasten corer EVENT LABEL: * LATITUDE: 15.825000 * LONGITUDE: -17.861667 * DATE/TIME: 1971-11-17T00:00:00 * ELEVATION: -2576.0 m * Recovery: 6 m * LOCATION: East Atlantic * CAMPAIGN: M25 * BASIS: Meteor (1964) * METHOD|DEVICE: Kasten corer
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Data used for constructing the age model for core GeoTü SL143. ... Location of the investigated sediment core GeoTü SL143 in the central Aegean Sea and the most important recent sediment source areas, transport processes and transport paths for the main clay mineral groups (after Ehrmann et al., 2007a, following Venkatarathnam and Ryan, 1971; Foucault and Mélières, 2000). Black arrows indicate the surface circulation (after Pickard and Emery, 1990; Aksu et al., 1995). The locations of cores MS27PT and GeoTü SL123 mentioned in the text are also indicated. The histograms indicate the generalised clay mineral composition of sediments delivered by NW and E Aegean Rivers (after Ehrmann et al., 2007a), the Nile River (after Hamann et al., 2009) and of Saharan dust in the eastern Mediterranean (after Chester et al., 1977). ... Combination of (A) the June insolation at 65°N, (B) the Nile sediment discharge deduced from core MS27PT (Revel et al., 2010; Caley et al., 2011), (C) the kaolinite/chlorite record in sediment core GeoTü SL123 from the southernmost Aegean Sea (Ehrmann et al., 2007b), and (D) the kaolinite/chlorite record in sediment core GeoTü SL143 from the central Aegean Sea. AHP: African humid periods, S sapropels in SL143, Y tephra layers, MIS=Marine Isotope Stages. ... Age/depth plot and kaolinite/chlorite peak heights ratios in sediments of core GeoTü SL143, central Aegean Sea, combined with the occurrences of tephra layers (Y2, Y5) and sapropel layers (S1, S3, S4) within the sequence. ... Late Quaternary
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Late Quaternary variations in the concentrations of smectite, illite, kaolinite, chlorite (3-point-running means) and the linear sedimentation rate (LSR, in cm/ka) in core GeoTü SL112. Dark grey bar marks sapropel layer S1; light grey bars show Heinrich Events H1 and H2. The solar insolation in July at 15°N (W/m2), the abundance of terrigenous matter in core 74KL from the western Arabian Sea (Sirocko et al., 1996; 14°19.26′N, 57°20.82′E) and the sea-surface temperature record of core MD79257 from the Mozambique Channel, western Indian Ocean (Bard et al., 1997; 20°24′S, 36°29′E) are shown for comparison. African Humid Period marked after deMenocal et al. (2000a). Arrows at the top indicate 14C dates used for constructing the age model (Table 2), YD: Younger Dryas, B–A: Bølling–Allerød, LGM: last glacial maximum. ... (a) Map of the southeastern Levantine Sea and adjacent areas with location of sediment core GeoTü SL112. The distribution of the main clay mineral groups smectite (sm), illite (ill), kaolinite (kao), chlorite (chl) and palygorskite (paly) in recent dust samples (arrows) is shown (various sources, Table 1). For exact location of samples II.7 and II.8 see Table 1. Present-day sea-surface circulation is represented by white elongated arrows (Pinardi and Masetti, 2000), 100-m depth contours are given. (b) Distribution of the main clay mineral smectite (sm), groups illite (ill), kaolinite (kao) and chlorite (chl) in marine surface samples (asterisks) and recent river/wadi samples (arrows). The data have been compiled from various sources (see Table 1). ... Ternary diagram showing the clay mineral composition of the late Quaternary sediments of core GeoTü SL112, subdivided into the glacial interval (41 samples), the African Humid Period (44 samples) and the late Holocene (48 samples). The clusters of the modern clay mineral assemblages in the southeastern Levantine Sea region are reproduced from Figure 2 for comparison. II Saharan Dust Assemblage, III Near East Assemblage, V Egyptian Wadi Assemblage, VI Nile Assemblage, VII SE Levantine Sea Assemblage. The fields of the Northern Dust Assemblage (I) and the Sinai Assemblage (IV) plot outside the chosen sector. ... Compilation of published clay mineral data from river channel and wadi surface sediments, dust samples and marine surface sediments in the southeastern Levantine Sea and the adjacent mainland ... Data used for constructing the age model for the investigated core GeoTü SL112 ... Late Quaternary
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Mineralogy of volcanic ash layers in sediments of the Okhotsk Sea (fraction 0.1–0.05 mm) ... LU stratigraphy in the Okhotsk Sea cores ... Okhotsk Sea core location and references ... Percentage of individual sediment fractions in cores V34-98 and 936 (lower panel) and the coefficient of correlation between MS and the content of these fractions (upper panel). The dotted and broken lines denote a minimal significant correlation coefficient at the 95% level of confidence for cores V34-98 and 936, respectively. Clay and silt are dominant in the sediments of both cores. There are positive correlations between MS and the silt–sand size fraction for both cores. In core 936, the correlation coefficient is larger for the coarse silt and very fine sand fractions than for fine–medium sand. In core V34-98 sediments, which are influenced by volcanic input, the MS-grain size correlations are reversed in comparison with core 936. ... Electron microprobe analyses of silic glassy tephra recovered at sediment cores ... sediment
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List of volcanic centres in southern Chile and Argentina with strong evidence for late Quaternary (post-glacial) activity, modified from Siebert et al. (2010). Arc segments: SVZ = Southern Volcanic Zone (N = North, T = Transitional, C = Central, S = South), AVZ = Austral Volcanic Zone, BA = back-arc volcanoes, after Stern (2004). Old GVP number refers to the indexing used by Siebert et al. (2010); VNum refers to the updated indexing introduced by GVP online (http://volcano.si.edu). Additional information on largest eruptions can be found in Supplementary Table 1. ... Post-glacial eruptive history of SVZ and AVZ volcanoes, as known from the historical and geological record. Calendar age is given in years before 1950 AD (historical eruptions or varve-dated), ka (Ar-Ar or stratigraphically constrained), or ka cal BP for 14C ages. Uncalibrated 14C ages are given where available, and were calibrated in OxCal4.2 (Bronk Ramsey, 2009) using the SHCal13 calibration curve (Hogg et al., 2013). The most important eruptions are highlighted in blue; the large (V > 1 km3) eruptions for which dispersal data are available are highlighted in red. These eruptions are thought to have left significant regional marker horizons which should be readily identifiable in sediment sections. Numbered references can be found in Supplementary Information. ... Maps of a) south-central and b) southernmost Chile and Argentina, showing the locations of volcanoes (listed in Table 1) and the archeological and palaeoenvironmental records in which tephra has been recognised (listed in Supplementary Table 2), as well as the distributions of the tephra deposits from each post-glacial large (≥1 km3 tephra; VEI/M ≥ 5) explosive eruption (listed in Supplementary Table 1), and of some of the environments amenable to tephra unit preservation. The legend for Fig. 2a also applies to Fig. 2b. Coloured lines are isopach contours, indicating the area in which the deposits of an eruption are inferred to be ≥10 cm, unless an otherwise labelled (number of centimetres) dashed line. These data are from the articles cited for the corresponding eruptions in Supplementary Table 1; the source volcanoes of these eruptions are named. Tephra-bearing core/exposure location labels refer to reference numbers in Supplementary Table 2; only distal exposure locations are plotted. The geographical data are from Natural Earth (natrualearthdata.com), except the peatland extent, which is from Yu et al. (2010). ... Lake sediment core... Tephra occurrence in sediment sections from various environments. Unless a name was already given to a specific tephra horizon in literature, all tephra horizons are given a unique name consisting of the (abbreviated) core or location name followed by the central depth of the tephra in the sediment core. Numbered references can be found in Supplementary Information. ... Maps of a) south-central and b) southernmost Chile and Argentina, showing the locations of volcanoes (listed in Table 1) and the archeological and palaeoenvironmental records in which tephra has been recognised (listed in Supplementary Table 2), as well as the distributions of the tephra deposits from each post-glacial large (≥1 km3 tephra; VEI/M ≥ 5) explosive eruption (listed in Supplementary Table 1), and of some of the environments amenable to tephra unit preservation. The legend for Fig. 2a also applies to Fig. 2b. Coloured lines are isopach contours, indicating the area in which the deposits of an eruption are inferred to be ≥10 cm, unless an otherwise labelled (number of centimetres) dashed line. These data are from the articles cited for the corresponding eruptions in Supplementary Table 1; the source volcanoes of these eruptions are named. Tephra-bearing core/exposure location labels refer to reference numbers in Supplementary Table 2; only distal exposure locations are plotted. The geographical data are from Natural Earth (natrualearthdata.com), except the peatland extent, which is from Yu et al. (2010).... Peat core... Schematic representation of preservation environments for tephra in southern Chile and Argentina. Most preservation is restricted to vegetated areas (i.e., the Andes), lakes (6) and peatland (2). In addition to lake and peat cores, marine cores (1) can also provide important tephrostratigraphic records. Distal tephra deposits (5, 7) are easily eroded away due to prevailing westerly winds over the Argentine steppe. Strong winds may also result in complex dispersal patterns reflected in the architecture of the deposits (5, 7). Tephra in lakes may not always result from primary fallout, and can instead be remobilised into the lake from the river catchment (3, 4).
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Quaternary... Nd and Sr isotopic ratios of the sediment samples from core GC05-DP02. ... εNd values of glacial and interglacial sediments of core GC05-DP02 and marine surface-sediment samples around Antarctica (Roy et al., 2007). ... Trace-element concentrations of the late Quaternary glacial and interglacial sediments from the southern Drake Passage plotted on the mid-ocean ridge basalt (MORB)-normalized spider diagram of Pearce (1983). Trace element distribution of the near-surface sediments from the northwestern and southeastern Bransfield Strait is shown for comparison (Lee et al., 2005). ... Sediment... Composition of trace and rare earth elements of sediment samples from core GC05-DP02. Concentrations in ppm. ... Down-core variations in sediment facies, magnetic susceptibility (MS), mean grain size, and wt.% of sand- and gravel-sized grains of core GC05-DP02.
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Descriptions of the 6 representative sediment cores. ... Map A shows the palaeo-valleys of the Pearl River mouth region during MIS 6, highlighted by areas where the Late Quaternary sequences are over 25 and 35m thick. These valleys are separated by rows of hills and blocks of rock outcrops. Map B shows palaeo-river channels during MIS 2. These channels separated areas of bedrock and areas where the older marine sequence was exposed and weathered. ... Radiocarbon dates from the selected 35 sediment cores. ... Map A shows the location of the Pearl River drainage basin, the Pearl River delta plains and estuary. Map B shows the locations of lithostratigraphic transects and representative sediment cores studied. ... a) Diatom data from sediment cores PK16, D13 and D6. Radiocarbon dates are shown as calendarkaBP. The abundances of diatom taxa are expressed as percentages of total diatoms counted for each samples. b) Diatom data from sediment cores JT81, V37 and BVC. Radiocarbon dates are shown as calendarkaBP. The abundances of diatom taxa are expressed as percentages of total diatoms counted for each samples.
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Correlation of paleomagnetic inclination and detrital carbonates (XRF Ca content) for upper parts of HOTRAX cores from Mendeleev-Alpha ridges (a) and P1-92/93-AR cores from the Northwind Ridge (b), south to north (Fig. 1 for core location). Where Ca content not measured, carbonate layers are shown by pink bars based on core descriptions. Correlation lines are shown for a prominent carbonate layer at ca. MIS 5/6 boundary (orange), inclination drop (grey), base of detrital carbonate deposition (punctured orange, panel (a) only), and top of brown sediment (purple, panel (b) only). 14C and AAR ages (ka) are shown in red and purple, respectively. 14C ages in core HLY0503-8JPC are grouped; see Fig. 2 for details of the upper part of this core and P1-92AR-P25. Note a two-fold change in core depth scale between southern and northern Mendeleev Ridge cores (between 8JPC and 10JPC). ... Average Late Quaternary sedimentation rates in cm/kyr at investigated sites (including published data from 96/12-1PC/ACEX, GreenICE, CESAR, NP26, P1-AR94-B8, and PS-51038-4) and summer sea-ice concentration contours for the late 20th century (in %, from Deser and Teng, 2008; no data near the North Pole). Arrows show major surface circulation features as in Fig. 1. Also shown are the maximal limits of Late Pleistocene glaciations (dotted lines). See Fig. 1 for core numbers and physiographic names. ... sediment stratigraphy... Sediment cores investigated for this study. ... Correlation of sediment cores from the Alaskan margin to the Mendeleev Ridge: sand content (>63 μm) (a, d, g—black), XRD dolomite content (a—green), Bering Strait Fe-oxide matches spliced from HLY0501-5JPC (b—magenta), carbonate and clastic sedimentary IRD>250 μm (c and e—orange and black, respectively), XRF Ca contеnt (d and g—green), XRF Mn content (f and h—blue), planktonic foraminifers >150 μm /g (f and h—red). 14C and AAR ages (ka)—in red and purple, respectively; 14C ages outside the calibration limit are shown in parentheses. Ages between 20–60 cm (arrows pointing to the right) and Bering Strait Fe-oxide peak (BS) for 92AR-P25 are spliced from 92AR-P2 (Polyak et al., 2007). Yellow shading—interglacial/interstadial units, light gray—interval with clastic IRD, dark gray—fine-grained LGM sediment. Note a large difference in core depth scales. ... Late Quaternary... Distribution of 14C ages vs. core depth (a) and linear sedimentation rates (LSR) (b) in cores from the Mendeleev Ridge (northern and southern MR data shown by different symbols). 14C data are from Darby et al. (1997), Poore et al. (1999a), Polyak et al. (2004), and Kaufman et al. (2008). Only standard oceanic reservoir correction is applied to 14C ages. Calibrated age scale is shown below. Core depth is normalized to the top of the second brown unit. Grey shading shows the LGM hiatus. Old ages around the interval of high detrital carbonate content are enclosed by an oval. The LSR value of 33 cm/kyr at ca. 8 ka is not shown.
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Location of studied surface sediment samples (Ormara transect, Hab-transect off Karachi and Indus transect) ... Location of studied surface sediment samples (Ormara transect, Hab-transect off Karachi and Indus transect) and core SO90 137KA off Pakistan. ... Proxies from coarse fraction analysis of core 137KA indicating aragonite dissolution: (A) coarse fraction content (>63 μm); (B) relative abundance of pteropods and heteropods including fragments; (C) Limacina inflata dissolution index distinguishing six dissolution stages, from 0 (perfect preservation) to 5 (worst preservation); (D) pteropod fragmentation index: fragments/(fragments+whole tests); (E) GISP2 Greenland ice core record (Grootes et al., 1993); bioturbation scale: dark grey=distinctly to indistinctly laminated sediments, light grey=indistinctly laminated sediments, white=bioturbated sediments, modified after von Rad et al., 1999). ... Geochemical proxies of core 137KA indicating organic and carbonate productivity (modified after von Rad et al., 1999): (A) total organic carbon (TOC) content; (B) bulk calcium carbonate content; (C) strontium concentration; (D) bulk aragonite content; (E) GISP2 Greenland ice core record (Grootes et al., 1993); bioturbation scale: dark grey=distinctly to indistinctly laminated sediments, light grey=indistinctly laminated sediments, white=bioturbated sediments, modified after von Rad et al., 1999). ... Sketch showing the two pteropod preservation modes in sediment core 137KA off Pakistan: (a) present-day situation with shallow deep winter mixing due to a weak NE monsoon, stable OMZ, absence of pteropods in core 137KA, pteropod occurrence restricted to shelf/upper continental slope; (b) good to excellent preservation during times of intermediate water formation down to 600 m water depth. The position of core 137KA is indicated by a star. ... Late Quaternary
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