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: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:M Thamban, V Purnachandra Rao, R.R Schneider
Down-core variations in grain size parameters, major clay mineral percentages, clay mineral ratios, illite 5 Å/10Å ratios and in core GC-5. Intervals showing enhanced gibbsite peaks are shown by + marks. The AMS 14C dates shown by arrows are uncorrected. Sea level curve is from the Barbados sea level record (Fairbanks, 1992).
... latequaternary... Location of the gravity cores and schematic geological map of the study area. Core GC-3 is from a topographic high and GC-5 from the upper continental slope of India.
... Representative X-ray diffractograms showing major clay minerals in the cores. C – chlorite, G – gibbsite, I – illite, K+C – kaolinite+chlorite, S – smectite.
... Down-core variations in grain size parameters, major clay mineral percentages, clay mineral ratios and illite 5 Å/10Å ratios in core GC-3. Presence of gibbsite is marked by + signs. Age scale is based on correlation of planktic oxygen isotope record with the stacked SPECMAP record.
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
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.
Contributors:Karen Fontijn, José A. Naranjo, David M. Pyle, Hugo Moreno-Roa, Stefan M. Lachowycz, Tamsin A. Mather, Harriet Rawson
List of volcanic centres in southern Chile and Argentina with strong evidence for lateQuaternary (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 sedimentcore... 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 sedimentcore. 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).
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 sedimentcore 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.
Location, depth, total core recovery, length of core section studied (cm below seafloor) and dominant lithology of sedimentcores collected adjacent to the CLSC
... Ages determined for cores adjacent to the CLSC with 14C techniques and the depth within the cores where the 120-ka disappearance level of Globigerinoides ruber (pink) is located
... Principal component loadings for three components in the HCl soluble fraction, recalculated on a detrital-free, CaCO3-free basis of sediments from cores collected adjacent to the CLSC, after subtraction of volcaniclastic layers
... Downcore plots of the HCl soluble Mn concentrations (wt%) recalculated on a detrital-free CaCO3-free basis of sedimentcores collected adjacent to the CLSC, indicating the ages (ka) of Mn peaks in each core as calculated from interpolation of 14C and palaeobiostratigraphic dates. Depths are recalculated (cmbsf*) after subtraction of volcaniclastic layers. *Peaks in Mn in core SO67/159 were determined using δ18O stratigraphy data after Gehrke (1992).
... Summary of bulk element concentrations and mean element partitioning of calcareous sediments in cores collected adjacent to the CLSC (n=40)
... hydrothermal sediments