Contributors:Ehrmann, Werner, Seidel, Martin, Schmiedl, Gerhard
Abstract: The ratio between the clay minerals kaolinite and chlorite has been investigated in high resolution in a lateQuaternarysedimentcore from the central Aegean Sea. The record spans the last ca. 105 ka. The kaolinite/chlorite ratio was used to reconstruct the fine-grained aeolian dust influx from the North African deserts, mainly derived from desiccated lake depressions. It therewith can be used as a proxy for wind activity, aridity and vegetation cover in the source area. The data document three major humid phases in North Africa bracketing the formation of sapropel layers S4, S3 and S1. They occur at >105-95 ka, 83.5-72 ka and 14-2 ka. The first two phases are characterised by relatively abrupt lower and upper boundaries suggesting a non-linear response of vegetation to precipitation, with critical hydrological thresholds. In contrast, the onset and termination of the last humid period were more gradual. Highest kaolinite/chlorite ratios indicating strongest aeolian transport and aridity occur during Marine Isotope Stage (MIS) 5b, at ca. 95-84 ka. The long-term decrease in kaolinite/chlorite ratios during the last glacial period indicates a gradual decline of deflatable lake sediments in the source areas.
Source: Supplement to: Ehrmann, Werner; Seidel, Martin; Schmiedl, Gerhard (2013): Dynamics of LateQuaternary North African humid periods documented in the clay mineral record of central Aegean Sea sediments. Global and Planetary Change, 107, 186-195, https://doi.org/10.1016/j.gloplacha.2013.05.010
Supplemental Information: Not Availble
Coverage: EVENT LABEL: (GeoTü SL143) * LATITUDE: 38.261830 * LONGITUDE: 25.103170 * ELEVATION: -665.0 m * LOCATION: Aegean Sea * DEVICE: Gravity corer (Kiel type)
Contributors:Werner Ehrmann, Gerhard Schmiedl, Martin Seidel
Data used for constructing the age model for core GeoTü SL143.
... Location of the investigated sedimentcore 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 sedimentcore GeoTü SL123 from the southernmost Aegean Sea (Ehrmann et al., 2007b), and (D) the kaolinite/chlorite record in sedimentcore 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.
Contributors:A.N. Derkachev, S.A Gorbarenko, A.S Astakhov, A Kaiser, D Nürnberg, J.R Southon
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 sedimentcores
Contributors:Werner Ehrmann, Gerhard Schmiedl, Tanja Kuhnt, Yvonne Hamann
LateQuaternary 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 sedimentcore 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 lateQuaternarysediments 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
Contributors:Gunnar Digerfeldt, Siv Olsson, Per Sandgren
Sediment chemical analysis of the core Xinias 1.
... Preliminary reconstruction of past lake-level changes in Lake Xinias, based on the lithology of the single sedimentcore sampled by Bottema (1979).
... LateQuaternary lake-level changes... Department of Quaternary Geology, Lund university, Tornavägen 13, S-22363 Lund, Sweden... Ostracods in selected samples of the early Holocene aragonitic (samples 1 and 2) and calcitic (samples 3 and 4) sediment in core Xinias 1a
... sediment stratigraphy... Topographic map of the past Lake Xinias, showing the location of the studied transect of sedimentcores. The shoreline before the recent drainage is indicated by broken line.
... Correlation of the cores Xinias 1–5 in the stratigraphical transect and the separate core Xinias 6.
Contributors:Kyu-Cheul Yoo, Ho Il Yoon, Young-Suk Bak, Yong Il Lee, Takuya Itaki, Hyoun Soo Lim, Jae Il Lee, Donghyun Kim
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 lateQuaternary 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.
Contributors:W.W.-S. Yim, F. Yu, G. Huang, Y. Zong
Descriptions of the 6 representative sedimentcores.
... Map A shows the palaeo-valleys of the Pearl River mouth region during MIS 6, highlighted by areas where the LateQuaternary 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 sedimentcores.
... 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 sedimentcores studied.
... a) Diatom data from sedimentcores 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 sedimentcores 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.
Contributors:Ruth E. Adler, Darrell S. Kaufman, Edward A. Council, Dennis D. Eberl, Leonid Polyak, Chuang Xuan, Jens Bischof, Reidar Løvlie, Dennis A. Darby, James E.T. Channell, David A. Schneider, Joseph D. Ortiz
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 LateQuaternarysedimentation 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... Sedimentcores investigated for this study.
... Correlation of sedimentcores 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.
... LateQuaternary... 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.
Location and lithology of the short cores collected in the eastern part of Puyehue Lake. The upper part of PU-II long core is also represented. Based on the nature of the heavy mineral fraction, correlations between cores are proposed. Tephras T1 and T2 do not contain heavy minerals and have a similar geochemical composition. They are therefore correlated according to macroscopical descriptions only. Tephras have been attributed the following ages: T1: AD 1960; T2: AD 1921–22; T3: AD 1907; T4: AD 1575; T5: unknown. See text for details.
... Bulk grain-size distribution of 3 typical tephra samples occurring in PU-II long core. All the samples contain a mixture of tephra particles and host sediment. Tephra grains were separated from the host sediment by sieving the samples at 75 and 420 µm (see text). (A) PU-II-500: sample dominated by coarse tephra particles, where the host sediment only represents 10% of the total sample and is completely discarded after sieving at 75 µm; (B) PU-II-744: sample composed of a mixture of coarse tephra particles and host sediment. Particles coarser than 75 µm may contain host sediment; (C) PU-II-179: fine tephra layer. In this case the >75 µm fraction does not contain all the tephra particles.
... Bulk and heavy mineralogy of the 15 thickest tephra layers collected in PU-II long core. In addition, the three youngest tephras (PU-II-16, 59 and 79) are also represented. See Supplementary Table 2 for more details.
... Geomorphology and Quaternary Geology, University of Liège, Belgium... Similarity coefficient (SC) calculations (after Borchardt et al, 1972) comparing major element analysis of tephras from PU-II-P2 and PU-I-P1 short cores
... AMS radiocarbon ages obtained on bulk sediment samples bracketing the T3 tephra in PU-I-P1 and PU-II-P2 short cores
... Lake sediments