Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations
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 be...
Main Author: | |
---|---|
Other Authors: | , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Universität Bremen
2007
|
Subjects: | |
Online Access: | https://media.suub.uni-bremen.de/handle/elib/2348 https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000106647 |
id |
ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/2348 |
---|---|
record_format |
openpolar |
spelling |
ftsubbremen:oai:media.suub.uni-bremen.de:Publications/elib/2348 2023-05-15T16:30:28+02:00 Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations Anwendungen und Qualitätsbeurteilung von XRF-Analysen zur Rekonstruktion spät-Pleistozäner Sedimentations- und Klima-Änderungen am NW Afrikanischen Kontinentalrand Tjallingii, Rik Wefer, Gerold Bickert, Torsten Röhl, Ursula Stein, Rüdiger 2007-02-12 application/pdf https://media.suub.uni-bremen.de/handle/elib/2348 https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000106647 eng eng Universität Bremen FB5 Geowissenschaften https://media.suub.uni-bremen.de/handle/elib/2348 urn:nbn:de:gbv:46-diss000106647 info:eu-repo/semantics/openAccess Alle Rechte vorbehalten NW Africa Cape Blanc XRF core scanner end member modeling eolian dust aridity vegetation cover productivity upwelling 550 550 Earth sciences and geology ddc:550 Dissertation doctoralThesis 2007 ftsubbremen 2022-12-18T23:09:13Z 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. Doctoral or Postdoctoral Thesis Greenland North Atlantic Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) Greenland |
institution |
Open Polar |
collection |
Media SuUB Bremen (Staats- und Universitätsbibliothek Bremen) |
op_collection_id |
ftsubbremen |
language |
English |
topic |
NW Africa Cape Blanc XRF core scanner end member modeling eolian dust aridity vegetation cover productivity upwelling 550 550 Earth sciences and geology ddc:550 |
spellingShingle |
NW Africa Cape Blanc XRF core scanner end member modeling eolian dust aridity vegetation cover productivity upwelling 550 550 Earth sciences and geology ddc:550 Tjallingii, Rik Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
topic_facet |
NW Africa Cape Blanc XRF core scanner end member modeling eolian dust aridity vegetation cover productivity upwelling 550 550 Earth sciences and geology ddc:550 |
description |
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. |
author2 |
Wefer, Gerold Bickert, Torsten Röhl, Ursula Stein, Rüdiger |
format |
Doctoral or Postdoctoral Thesis |
author |
Tjallingii, Rik |
author_facet |
Tjallingii, Rik |
author_sort |
Tjallingii, Rik |
title |
Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
title_short |
Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
title_full |
Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
title_fullStr |
Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
title_full_unstemmed |
Application and quality of X-Ray fluorescence core scanning in reconstructing late Pleistocene NW African continental margin sedimentation patterns and paleoclimate variations |
title_sort |
application and quality of x-ray fluorescence core scanning in reconstructing late pleistocene nw african continental margin sedimentation patterns and paleoclimate variations |
publisher |
Universität Bremen |
publishDate |
2007 |
url |
https://media.suub.uni-bremen.de/handle/elib/2348 https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000106647 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland North Atlantic |
genre_facet |
Greenland North Atlantic |
op_relation |
https://media.suub.uni-bremen.de/handle/elib/2348 urn:nbn:de:gbv:46-diss000106647 |
op_rights |
info:eu-repo/semantics/openAccess Alle Rechte vorbehalten |
_version_ |
1766020192459030528 |