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  • Abstract: Late Neogene planktonic foraminiferal biostratigraphy of DSDP Site 296, Leg 31, reveals this site as an ideal reference section for correlation of Blow's low-latitude zonation with the mid-latitude zonation for temperate faunal assemblages developed in this paper and earlier for DSDP Site 310, Leg 31 (Keller). Abundance of temperate species of Globorotalia (G. inflata, G. puncticulata, G. crassaformis, G. conomiozea) permit correlation with the zonal subdivision developed at Site 310 based on these species. Evolutionary changes within the Globorotalia inflata group also appear to be consistent biostratigraphie markers in mid latitudes; a primitive variety of this species first appears at about 3.3-3.1 Ma, G. inflata praeinflata appears at about 2.6 Ma, and the modern form appears at about 2.2-2.1 Ma. Quantitative analyses of planktonic foraminifera at DSDP Site 296 reveal an inversely reciprocal frequency oscillation between species of Globorotalia and the Globigerina-Globigerinita group. Cool climatic periods are characterized by high frequencies in the Globigerina-Globigerinita group and low frequencies in the Globorotalia group, whereas warm intervals are marked by high frequencies in the Globorotalia group and low frequencies in the Globigerina-Globigerinita group. Five cool paleoclimatic events can be recognized between early Pliocene and late Pleistocene: 4.4 Ma, 3.2-3.1 Ma, 2.4-2.2 Ma, 1.2 Ma, and 0.7 Ma. These paleoclimatic/paleoceanographic events have also been recognized in planktonic foraminifera of the Central and Northeast Pacific DSDP Sites 310 and 173 and also correlate to cold events recognized in oxygen isotope measurements of DSDP Site 310 and in equatorial Pacific cores. Category: geoscientificInformation Source: Supplement to: Keller, Gerta (1979): Late Neogene planktonic foraminiferal biostratigraphy and paleoceanography of the Northwest Pacific DSDP Site 296. Palaeogeography, Palaeoclimatology, Palaeoecology, 27, 129-154, https://doi.org/10.1016/0031-0182(79)90097-X Supplemental Information: Sample 31-296-20-4,100-102 was contaminated and therefore not included in the investigation Coverage: EVENT LABEL: * LATITUDE: 29.340200 * LONGITUDE: 133.525300 * DATE/TIME: 1973-07-10T00:00:00 * ELEVATION: -2920.0 m * Penetration: 1087 m * Recovery: 301.2 m * LOCATION: North Pacific/Philippine Sea/RIDGE * CAMPAIGN: Leg31 * BASIS: Glomar Challenger * METHOD/DEVICE: Drilling/drill rig
    Data Types:
    • Tabular Data
    • Dataset
  • Abstract: The upper 1200 m of pre-Pliocene sediment recovered by Cape Roberts Project (CRP) drilling off the Victoria Land coast of Antarctica between 1997-1999 has been subdivided into 54 unconformity-bound stratigraphic sequences, spanning the period c. 32 to 17 Ma. The sequences are recognised on the basis of the cyclical vertical stacking of their constituent lithofacies, which are enclosed by erosion surfaces produced during the grounding of the advancing ice margin onto the sea floor. Each sequence represents deposition in a range of offshore shelf to coastal glacimarine sedimentary environments during oscillations in the ice margin across the Western Ross Sea shelf, and coeval fluctuations in water depth. This paper applies spectral analysis techniques to depth- and time-series of sediment grain size (500 samples) for intervals of the core with adequate chronological data. Time series analysis of 0.5-l.0m-spaced grainsize data spanning sequences 9-11 (CRP-2/2A) and sequences 1-7 (CRP-3) suggests that the length of individual sequences correspond to Milankovitch frequencies, probably 41 k.y., but possibly as low as 100 k.y. Higher frequency periodic components at 23 k.y. (orbital precession) and 15-10 k.y. (sub-orbital) are recognised at the intrasequence-scale, and may represent climatic cycles akin to the ice rafting episodes described in the North Atlantic Ocean during the Quaternary. The cyclicity recorded by glacimarine sequences in CRP core provides direct evidence from the periphery of Antarctica for orbital oscillations in the size of the Oligocene-Early Miocene East Antarctic Ice Sheet. Category: geoscientificInformation Source: Supplement to: Naish, Tim R; Barrett, Peter J; Dunbar, Gavin B; Woolfe, Ken; Dunn, A G; Henrys, Stuart A; Claps, Michele; Powell, Ross; Fielding, Christopher R (2001): Sedimentary cyclicity in CRP drillcore, Victoria Land Basin, Antarctica. Terra Antartica, 8(3), 225-244, hdl:10013/epic.28205.d001 Supplemental Information: Not Availble Coverage: EVENT LABEL: (14.2 km at 096° true from Cape Roberts) * LATITUDE: -77.005983 * LONGITUDE: 163.719450 * DATE/TIME: 1998-10-01T00:00:00 * ELEVATION: -177.9 m * Recovery: 57.42 m * LOCATION: off Cape Roberts, Ross Sea, Antarctica * CAMPAIGN: CRP-2 * BASIS: Sampling/drilling from ice * METHOD|DEVICE: Core wireline system EVENT LABEL: * LATITUDE: -77.006000 * LONGITUDE: 163.719000 * DATE/TIME START: 1999-10-09T00:00:00 * DATE/TIME END: 1999-11-19T00:00:00 * ELEVATION: -295.0 m * Penetration: 939 m * Recovery: 936 m * LOCATION: Ross Sea * CAMPAIGN: CRP-3 * BASIS: Sampling/drilling from ice * METHOD|DEVICE: Core wireline system
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  • Abstract: The primary productivity dynamics of the last 200,000 years in the Sulu Sea was reconstructed using the abundance of the coccolithophore Florisphaera profunda in the IMAGES MD97-2141 core. We find that primary productivity was enhanced during glacial periods, which we suggest is due to a stronger East Asian winter monsoon. During the last 80 kyr, eight significant increases in primary productivity (PP) in the Sulu Sea are similar to East Asian winter monsoon changes recorded in Chinese loess. The PP maxima are not linked with Heinrich events (HE) in the North Atlantic, although four PP peaks are synchronous with HE. The PP oscillations have frequencies near those of the Dansgaard-Oeschger cycles in Northern Hemisphere ice records and indicate a teleconnection of the East Asian winter monsoon with Greenland climate. In this Sulu Sea record the East Asian winter monsoon oscillates with periodicities of ~6, 4.2-3.4, 2.3, and 1.5 kyr. In particular, the 1.5 kyr cycle exhibits a strong and pervasive signal from stage 6 to the Holocene without any ice volume modulation. This stationarity suggests that the 1.5 kyr cycle is not driven by some high-latitude forcing. Category: geoscientificInformation Source: Supplement to: de Garidel-Thoron, Thibault; Beaufort, Luc; Linsley, Braddock K; Dannenmann, Stefanie (2001): Millennial-scale dynamics of the east Asian winter monsoon during the last 200,000 years. Paleoceanography, 16(5), 491-502, https://doi.org/10.1029/2000PA000557 Supplemental Information: Calendar ages have been calculated using a 400 year reservoir correction and applying the Stuiver and Braziunas (1993) calibration curve for samples younger than 20,000 calendar years in age and a U/Th calibration curve for the samples older than 20,000 calendar years (Bard et al., 2993). Coverage: EVENT LABEL: (MD972141) * LATITUDE: 8.786000 * LONGITUDE: 141.295000 * Recovery: 36.3 m * CAMPAIGN: MD106 * BASIS: Marion Dufresne (1995) * METHOD/DEVICE: Calypso Corer
    Data Types:
    • Tabular Data
    • Dataset
  • Climate variability and El Niño Southern Oscillation
    Data Types:
    • Tabular Data
    • Dataset
  • Abstract: The El Niño-Southern Oscillation (ENSO) is a globally important factor in today's climate dynamics. Annually laminated oil shales from the maar lake of Messel (Germany) provide high-resolution sedimentological and paleoenvironmental data of a time interval of ~600 k.y. during the Eocene greenhouse phase. Individual laminae consist of a light spring and summer algal layer (Tetraedron minimum layer) and a dark winter layer composed of terrigenous background sediment. Four sections were selected from the core of the Messel 2001 well in order to count varves and to measure total varve thickness and the thickess of light and dark laminae. Spectral analyses were done in order to detect possible cyclic fluctuations in varve thickness. Fluctuations are significant in the quasi-biennial (2.1-2.5 yr) and low-frequency band (2.8-3.5 yr, 4.9-5.6 yr), thus showing that algal growth as well as the background sedimentation were controlled by ENSO effects at least over a time interval of 600 k.y. This confirms the existence of a previously postulated robust Eocene ENSO. Significant peaks within a quasi-decadal (10-11 yr), interdecadal (17-26 yr), and multidecadal band (~52 yr, ~82 yr) show either the enduring influence of more or less cyclic instabilities or the influence of solar cycles. Category: geoscientificInformation Source: Supplement to: Lenz, Olaf K; Wilde, Volker; Riegel, Walter; Harms, Franz-Jürgen (2010): A 600 k.y. record of El Nino-Southern Oscillation (ENSO): Evidence for persisting teleconnections during the Middle Eocene greenhouse climate of Central Europe. Geology, 38(7), 627-630, https://doi.org/10.1130/G30889.1 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 49.917841 * LONGITUDE: 8.758867 * LOCATION: Messel, Germany * METHOD|DEVICE: Core drilling
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  • Abstract: We report 150 kyr records of U37K' sea-surface temperature (SST) and carbonate content with 150-200-year sampling resolution from the southern South China Sea (SCS) in the northern margin of the Western Pacific Warm Pool (WPWP) using IMAGES Core MD972151. The glacial/interglacial SST change is about 5 °C for Termination II (23.5 to 28.5°C) and 4°C for Termination I (24 to 28°C). The simultaneous rise of sea level and U37K' SST during Termination I suggests that sea-level change has played an important role in the SCS SST variability by influencing the exchange of tropical ocean warm surface water with the SCS through the Sunda Shelf region (sill depth 30-50 m). When sea-level drop was less than 30 m relative to today's, MD972151 SST was constantly above 27 °C, a situation which occurred during MIS 5e, part of MIS5c and 5a, and over the last 11 kyr. Sea-level change was also the main control on carbonate content in the SCS; this was lower during low sea-level stands due to the dilution effect of enhanced terrigenous inputs. Within the limitations of our age model, millennial-scale SST oscillations (1.5°C over a few hundred years) occurred frequently during the entire glacial period, correlating reasonably well with the Hulu monsoon record from eastern China and the Dansgaard-Oeschger (D-O) cycles recorded for high-latitude regions in the Northern Hemisphere. Such correlations suggest a possible teleconnection between higher latitude atmospheric forcing and low-latitude climate oscillations in the western Pacific tropical region via the Asian monsoon system. Carbonate content also reveals millennial-scale oscillations during the glacial period, with higher content correlated with higher SST. Millennial-scale fluctuations of SST and carbonate contents at this low-latitude SCS provide additional evidence that high-frequency climate changes are global phenomena. Category: geoscientificInformation Source: Supplement to: Zhao, Meixun; Huang, Chi-Yue; Wang, Chia-Chun; Wei, Ganjian (2006): A millennial-scale U37K' sea-surface temperature record from the South China Sea (8°N) over the last 150 kyr: Monsoon and sea-level influence. Palaeogeography, Palaeoclimatology, Palaeoecology, 236(1-2), 39-55, https://doi.org/10.1016/j.palaeo.2005.11.033 Supplemental Information: Not Availble Coverage: EVENT LABEL: (MD972151) * LATITUDE: 8.728000 * LONGITUDE: 109.869000 * ELEVATION: -1598.0 m * Recovery: 26.72 m * LOCATION: South China Sea * CAMPAIGN: MD106 * BASIS: Marion Dufresne (1995) * METHOD/DEVICE: Calypso Corer
    Data Types:
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  • Abstract: Laboratory experiments show that undercooling to about -5°C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5°C and -5°C or -10°C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50°C. l4CO2 incorporation after freezing to -20°C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface. Category: geoscientificInformation Source: Supplement to: Meyer, M A; Huang, G-H; Morris, G J; Friedmann, E Imre (1988): 2.2 The effect of low temperatures on Antarctic endolithic green algae. Polarforschung, 58(2/3), 113-119, hdl:10013/epic.29606.d001 Supplemental Information: Not Availble Coverage: Not Available
    Data Types:
    • Tabular Data
    • Dataset
  • Abstract: The long-term record of glacial/interglacial cycles indicates three major paleoceanographic regimes in the Norwegian Sea. The period since the first major glaciation over Scandinavia at 2.56 Ma is characterized by high-frequency, low-amplitude oscillations of ice-rafted debris inputs, a lowered salinity, and decreased carbonate shell production in surface waters as well as overall strong carbonate dissolution at the sea floor. These conditions indicate a more zonal circulation pattern in the Northern Hemisphere and a relative isolation of surface and bottom waters in the Norwegian Sea. The generally temperate glacial climate was only interrupted by episodic weak intrusions of warm Atlantic waters. These intrusions have been detected in considerable magnitude only at Site 644, and thus are restricted to areas much closer to the Norwegian shelf than during earlier periods. The interval from 1.2 to 0.6 Ma is characterized by an increase in carbonate shell production and a better preservation, as well as a change in frequency patterns of ice-rafted debris inputs. This pattern reflects increasing meridionality in circulation-strengthening contrasts in the Norwegian Sea between strong glaciations and warm interglacials. The past 0.6 Ma reveal high-amplitude oscillations in carbonate records that are dominated by the 100-k.y. frequency pattern. Glacial/interglacial sedimentary cycles in the ODP Leg 104 drill sites reveal a variety of specific dark lithofacies. These dark diamictons reflect intense iceberg rafting in surface waters fed by surges along the front of marine-based parts of the continental ice sheets in the southeastern sector of the Norwegian Sea and are associated with resuspension of reworked fossil organic carbon and strong dissolution at the sea floor. Piling up of huge iceberg barriers along the Iceland-Faeroe-Scotland Ridge might have partially blocked off surface water connections with the North Atlantic during these periods Category: geoscientificInformation Source: Supplement to: Henrich, Rüdiger (1989): Glacial/interglacial cycles in the Norwegian Sea: sedimentology, paleoceanography, and evolution of late Pliocene to Quaternary northern hemisphere climate. In: Eldholm, O; Thiede, J; Taylor, E; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 104, 189-232, https://doi.org/10.2973/odp.proc.sr.104.116.1989 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 67.225000 * LONGITUDE: 2.928300 * DATE/TIME START: 1985-06-28T14:40:00 * DATE/TIME END: 1985-06-29T20:15:00 * ELEVATION: -1294.0 m * Penetration: 221.1 m * Recovery: 214.61 m * LOCATION: Norwegian Sea * CAMPAIGN: Leg104 * BASIS: Joides Resolution * METHOD|DEVICE: Drilling/drill rig EVENT LABEL: * LATITUDE: 67.220000 * LONGITUDE: 2.930000 * DATE/TIME START: 1985-06-29T20:15:00 * DATE/TIME END: 1985-07-01T15:00:00 * ELEVATION: -1292.0 m * Penetration: 199.6 m * Recovery: 194.93 m * LOCATION: Norwegian Sea * CAMPAIGN: Leg104 * BASIS: Joides Resolution * METHOD|DEVICE: Drilling/drill rig EVENT LABEL: * LATITUDE: 67.715000 * LONGITUDE: 1.033300 * DATE/TIME START: 1985-08-03T06:07:00 * DATE/TIME END: 1985-08-08T01:45:00 * ELEVATION: -2780.0 m * Penetration: 565.2 m * Recovery: 458.29 m * LOCATION: Norwegian Sea * CAMPAIGN: Leg104 * BASIS: Joides Resolution * METHOD|DEVICE: Drilling/drill rig
    Data Types:
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  • Abstract: Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the occurrence and future persistence of these endemic species. In order to evaluate the impact of past climate changes on the endemic Argan tree in southern Morocco, we reconstructed its modern range using an extensive pollen dataset. The modern pollen distribution off southwestern Morocco was then utilized to interpret the high-resolution pollen record with complementary micro-charcoal and XRF element records from a marine sediment core GeoB8601-3 off Cape Ghir in southwestern Morocco covering the last three millennia. This multi-proxy study has shown clear evidence of wetter conditions resulting in higher fluvial input which could be correlated with a negative mode of the North Atlantic Oscillation (NAO), in contrast to the published pollen and XRF element records from another nearby core that showed limited effect of climate changes. On the other hand, clear opposite trend between the pollen occurrences of Argania spinosa and the fire frequency was observed throughout our fossil record. The increase of Argania spinosa pollen occurrences, along with herbaceous taxa, and lower fire frequency might suggest an increase in human impact on the landscape leading to a sparse vegetation cover and subsequently increased erosion. The reconstructed pollen-based vegetation, micro-charcoal-based fire activities and geochemical changes in our marine record suggest interplay of climate and anthropogenic effects on the landscape. Category: geoscientificInformation Source: Supplement to: Zhao, Xueqin; Dupont, Lydie M; Cheddadi, Rachid; Kölling, Martin; Reddad, Hanane; Groeneveld, Jeroen; Ain-Lhout, Fatima Zohra; Bouimetarhan, Ilham (2019): Recent climatic and anthropogenic impacts on endemic species in southwestern Morocco. Quaternary Science Reviews, 221, 105889, https://doi.org/10.1016/j.quascirev.2019.105889 Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: The Mesozoic Era experienced several instances of abrupt environmental change that are associated with instabilities in the climate, reorganizations of the global carbon cycle, and elevated extinction rates. Often during these perturbations, oxygen-deficient conditions developed in the oceans resulting in the widespread deposition of organic-rich sediments - these events are referred to as Oceanic Anoxic Events or OAEs. Such events have been linked to massive injections of greenhouse gases into the ocean- atmosphere system by transient episodes of voluminous volcanism and the destabilization of methane clathrates within marine environments. Nevertheless, uncertainty surrounds the specific environmental drivers and feedbacks that occurred during the OAEs that caused perturbations in the carbon cycle; this is particularly true of the Early Jurassic Toarcian OAE (ca. 183.1 Ma). Here, we present biostratigraphically constrained carbon isotope data from western North America (Alberta and British Columbia, Canada) to better assess the global extent of the carbon cycle perturbations. We identify the large negative carbon isotope excursion associated with the OAE along with high-frequency oscillations and steps within the onset of this excursion. We propose that these high-frequency carbon isotope excursions reflect changes to the global carbon cycle and also that they are related to the production and release of greenhouse gases from terrestrial environments on astronomical timescales. Furthermore, increased terrestrial methanogenesis should be considered an important climatic feedback during Ocean Anoxic Events and other similar events in Earth history after the proliferation of land plants. Category: geoscientificInformation Source: Supplement to: Them II, Theodore R; Gill, Benjamin C; Gröcke, Darren R; Tulsky, E T; Martindale, Rowan C; Poulton, T P; Smith, P L (2017): High-resolution carbon isotope records of the Toarcian Oceanic Anoxic Event (Early Jurassic) from North America and implications for the global drivers of the Toarcian carbon cycle. Earth and Planetary Science Letters, 459, 118-126, https://doi.org/10.1016/j.epsl.2016.11.021 Supplemental Information: Not Availble Coverage: Not Available
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