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  • 175-1078C; Benguela Current, South Atlantic Ocean; DRILL; Drilling/drill rig; Joides Resolution; Leg175; Ocean Drilling Program; ODP  (3)
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  • 1
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    PANGAEA
    In:  Supplement to: Dupont, Lydie M; Behling, Hermann; Kim, Jung-Hyun (2008): Thirty thousand years of vegetation development and climate change in Angola (Ocean Drilling Program Site 1078). Climate of the Past, 4, 107-124, https://doi.org/10.5194/cp-4-107-2008
    Publication Date: 2024-01-09
    Description: ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant.
    Keywords: 175-1078C; Benguela Current, South Atlantic Ocean; DRILL; Drilling/drill rig; Joides Resolution; Leg175; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
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  • 2
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    PANGAEA
    In:  Supplement to: Hessler, Ines; Steinke, Stephan; Groeneveld, Jeroen; Dupont, Lydie M; Wefer, Gerold (2011): Impact of abrupt climate change in the tropical southeast Atlantic during Marine Isotope Stage (MIS) 3. Paleoceanography, 26, PA4209, https://doi.org/10.1029/2011PA002118
    Publication Date: 2024-01-09
    Description: High resolution planktonic foraminifera Mg/Ca paleotemperatures and oxygen isotopes of seawater of Ocean Drilling Program (ODP) Site 1078 (off Angola) have been reconstructed and reveal insights into the seasonal thermal evolution of the Angola Current (AC), the Angola-Benguela Front (ABF), and the Benguela Current (BC) during the last glacial (50-23.5 ka BP). Special emphasis is put on time intervals possibly associated with the North Atlantic Heinrich Stadials (HS), which are thought to lead to an accumulation of heat in the South Atlantic due to a reduction of the Atlantic Meridional Overturning Circulation (AMOC). Within dating uncertainties, Globigerinoides ruber (pink) Mg/Ca-based sea surface temperature (SST) estimates that represent southern hemisphere summer surface conditions show several warming episodes that coincide with North Atlantic HS, thus supporting the concept of the bipolar thermal seesaw. In contrast, the Mg/Ca-based temperatures of Globigerina bulloides, representing the SST of the ABF/BC system during southern hemisphere winter, show no obvious response to the North Atlantic HS in the study area. We suggest that surface water cooling during the winter season is due to enhanced upwelling or upwelling of colder water masses which has most likely mitigated a warming of the ABF/BC system during HS. We further speculate that the seasonal asymmetry in our SST record results from seasonal differences in the dominance of atmospheric and oceanic teleconnections during periods of northern high latitude cooling.
    Keywords: 175-1078C; Benguela Current, South Atlantic Ocean; DRILL; Drilling/drill rig; Joides Resolution; Leg175; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
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  • 3
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Hessler, Ines; Dupont, Lydie M; Handiani, Dian Noor; Paul, André; Merkel, Ute; Wefer, Gerold (2012): Masked millennial-scale climate variations in South West Africa during the last glaciation. Climate of the Past, 8(2), 841-853, https://doi.org/10.5194/cp-8-841-2012
    Publication Date: 2024-01-09
    Description: To address the connection between tropical African vegetation development and high-latitude climate change we present a high-resolution pollen record from ODP Site 1078 (off Angola) covering the period 50-10 ka BP. Although several tropical African vegetation and climate reconstructions indicate an impact of Heinrich Stadials (HSs) in Southern Hemisphere Africa, our vegetation record shows no response. Model simulations conducted with an Earth System Model of Intermediate Complexity including a dynamical vegetation component provide one possible explanation. Because both precipitation and evaporation increased during HSs and their effects nearly cancelled each other, there was a negligible change in moisture supply. Consequently, the resulting climatic response to HSs might have been too weak to noticeably affect the vegetation composition in the study area. Our results also show that the response to HSs in southern tropical Africa neither equals nor mirrors the response to abrupt climate change in northern Africa.
    Keywords: 175-1078C; Benguela Current, South Atlantic Ocean; DRILL; Drilling/drill rig; Joides Resolution; Leg175; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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