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| Titel |
Temperature, vegetation and precipitation variability in the Nile River drainage during the past 27,000 years: Insights from molecular and isotopic proxies |
| VerfasserIn |
Isla Castañeda, Stefan Schouten, Jürgen Pätzold, Enno Schefuß |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250083966
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| Zusammenfassung |
| The paleoclimate history of the Eastern Mediterranean (EM) region is of much interest due to
its long history of human occupation. To date, much of our knowledge of past climate in the
EM region comes from marine sedimentary records. These indicate that since the Last Glacial
Maximum, major and sometimes abrupt sea surface temperature (SST) fluctuations occurred
in response to global climate events including the Younger Dryas (YD), the Bølling-Allerød,
and Heinrich Event 1 (H1). In comparison, less is known regarding continental
paleoclimate conditions in this region due to a scarcity of well-dated continuous
climate archives, particularly from Saharan North Africa. Here, we present new
reconstructions of continental precipitation (plant leaf wax δD), C3 vs. C4 vegetation (plant
leaf wax δ13C) and soil temperature (MBT/CBT paleothermometer) in the Nile
River catchment in conjunction with previously published U37k’ and TEX86SST
reconstructions from the EM Sea. Our multiproxy records indicate that relative to the
present, the LGM was characterized by arid conditions with cooler SST and soil
temperatures in the catchment. The H1 event stands out as a major excursion in
nearly all proxies and is characterized by an abrupt decrease in SST and the most
arid conditions of the past 27,000 years. The African Humid Period (AHP) of the
early Holocene is the wettest interval of the entire record and is observed from
~10,000 to 5,500 cal BP, with maximum wet conditions noted at ~8,000 cal BP.
Interestingly, a rather abrupt cooling is noted in the MBT/CBT record at ~5.5 cal
kyr, coinciding with the end of the AHP off west Africa; however, the transition
out of the AHP is more gradual in the δD record. Overall both the continental and
marine climate records indicate millennial scale climate variability. Our records
also shed light on shifting sources of organic matter in response to the sequential
cessation and re-initiation of different tributaries to the main flow of the Nile River. |
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