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  4. Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations
 
Zitierlink URN
https://nbn-resolving.de/urn:nbn:de:gbv:46-diss000106647

Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations

Veröffentlichungsdatum
2007-02-12
Autoren
Tjallingii, Rik  
Betreuer
Bickert, Torsten  
Röhl, Ursula  
Gutachter
Stein, Rüdiger  
Zusammenfassung
Abrupt climate changes during the last glacial-interglacial cycle known as Dansgaard-Oeschger (D-O) oscillations. Although, it is evident that these climate changes are most severe in the North Atlantic realm, the forcing of the D-O climate oscillations is still controversial. Feedback mechanisms between ocean heat transport, atmospheric circulation, and low latitude climate changes are thought to play an important role in the continuation, amplification, and possibly initiation of D-O climate oscillations. However, the role low-latitude climate zones and their potential to influence or initiate high-latitude climate change is still unknown. The region off Cape Blanc (Northwest Africa) is situated between the North Atlantic mid latitudes and the equatorial Atlantic, and is a key region to study climate forcing in the subtropics.Millennial-scale changes of the terrigenous sediment composition based on non-destructive XRF core scanning and grain-size variations of the terrigenous sediment fraction indicate coherent high- and low- climate variations during the last glacial-interglacial cycle. Water corrected X-Ray Fluorescence (XRF) Core Scanner measurements are used to obtaining chemical changes of the eolian dust input. End member modeling of the terrigenous fraction reveal two eolian end members, and a hemipelagic end member. Additionally, opal and organic matter accumulations are used to reconstruct upwelling intensities and surface water productivity off Cape Blanc. These data indicate increased continental aridity, trade wind intensities, and upwelling intensities accompanied by reduced surface water productivity associated with North Atlantic Heinrich events and extreme Greenland stadial events. Moreover, both the eolian contributions off Cape Blanc and simulations of the vegetation (obtained from the Atmosphere-Ocean-Vegetation model CLIMBER 2) indicate that Northwest African humidity is forced by the strength of the African Monsoon during interglacial conditions.
Schlagwörter
NW Africa

; 

Cape Blanc

; 

XRF core scanner

; 

end member modeling

; 

eolian dust

; 

aridity

; 

vegetation cover

; 

productivity

; 

upwelling.
Institution
Universität Bremen  
Fachbereich
Fachbereich 05: Geowissenschaften (FB 05)  
Dokumenttyp
Dissertation
Zweitveröffentlichung
Nein
Lizenz
Alle Rechte vorbehalten
Sprache
Englisch
Dateien
Lade...
Vorschaubild
Name

00010664.pdf

Size

7.93 MB

Format

Adobe PDF

Checksum

(MD5):6865ec80fb26e3f83660ac8f520b39d9

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