Oceanic and climatic variability in the eastern tropical North Atlantic and over western Sahel during the last deglaciation and the Holocene [Elektronische Ressource] / vorgelegt von Ilham Bouimetarhan

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Oceanic and climatic variability in the eastern tropical North Atlantic and over western Sahel during the last deglaciation and the Holocene Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. Nat) am Fachbereich Geowissenschaften der Universität Bremen Vorgelegt von Ilham Bouimetarhan Bremen, January 2009 Tag des Kolloquiums 17.04.2009 Gutachter: Frau PD Dr. Karin Zonneveld Frau Prof. Dr. Gesine Mollenhauer Prüfer: Frau Dr. Lydie Dupont Herr Prof. Dr. Tilo von Dobeneck thBouimetarhan, Ilham 24 of January, 2009 Department of Geosciences/Marum, Universität Bremen, Klagenfurter Strasse, D-28359 Bremen, Germany Erklärung Hiermit versichere ich, dass ich 1. die Arbeit ohne unerlaubte fremde Hilfe angefertigt habe, 2. keine anderen als die von mir angegebenen Quellen und Hilfsmittel benutzt habe und 3. die den benutzten Werken wörtlich oder inhaltlich entnommenen Stellen als solche kenntlich gemacht habe. Bremen, den 24. Januar 2009 Ilham Bouimetarhan Il faut se servir de toutes les ressources de l’intelligence, de l’imagination, des sens, de la mémoire pour avoir une intuition distincte des propositions simples. Régle 12 (Les régles pour la direction de l’esprit, 1629) René Descartes Acknowledgements I owe my gratitude to PD Dr.

Informations

• Publié par: universitat_bremen
• Publié le: 01 janvier 2009
• Nombre de lectures: 1 664
• Langue: English
• Poids de l'ouvrage: 7 Mo

Extrait

Oceanic and climatic variability

in the eastern tropical North Atlantic and over

western Sahel during the last deglaciation and the

Holocene

Dissertation zur Erlangung des Doktor

s der Naturwidegrassenschaften

(Dr. rer. Nat) am Fachbereich Geowissenschaften

ed Universität Bremenr

Vorgelegt von

an hrIlham Bouimeta

Bremen, January 2009

Tag des Kolloquiums

.2009 17.04

tachter: Gu

Frau PD Dr. Karin Zonneveld

Frau Prof. Dr. Gesine Mollenhauer

Prüfer:

. LydierFrau Dupont D

Herr Prof. Dr. Tilo von Dobeneck

Bouimetarhan, Ilham

24th of January, 2009

Department of Geosciences/Marum, Universität Bremen, Klagenfurter Strasse, D-28359
Bremen, Germany

klärung rE

Hiermit versichere ich, dass ich

1. die Arbeit ohne unerlaubte fremde Hilfe angefertigt habe,

2. keine anderen als die von mir angegebenen Quellen und
Hilfsmittel benutzt habe und

3. die den benutzten Werken wörtlich oder inhaltlich
entnommenen Stellen als solche kenntlich gemacht habe.

Bremen, den 24. Januar 2009

Ilhamrhan etaBouim

es de l’intelligence, Il faut se servir de toutes les ressourc

sens, de la mémoire gination, desde l’ima

te pour avoir une intuition distinc

des propositions simples.

Régle 12

(Les régles pour la direction de l’esprit, 1629)

René Descartes

Acknowledgements

I owe my gratitude to PD Dr. Karin Zonneveld who gave me the opportunity to
undertake this PhD project and, with accurate suggestions, advised me throughout.

My most sincere thanks go to Dr. Lydie Dupont who introduced me to the beautiful
world of pollen and who shared with me her knowledge about African vegetation and
climate. Her permanent support, interest, generosity, and encouragment has made
possible for me to complete this thesis. I would like to warmly thank Dr. Enno
Schefuß who always helped me to face with optimism and enthusiasm “all” scientific
problems. I feel very lucky to have worked with him. Special thanks go to Dr. Stefan
Mulitza and Prof. Dr. Gesine Mollenhauer for the fruitful discussions and
ons. suggesti

I would like to sincerely thank all the people at the Department of Geosciences and
Marum in Bremen University who somehow contributed to this work. Many thanks
to Dr. Fabienne Marret, who received me during two months at Liverpool University,
for her endless help and support. Sven Forke and Mirja Hoins are thanked for their
help with the laboratory work, you made my life so easy and my slides so nice to look
at…you always did a great job…Thank you. I would like also to thank everybody in
the “Historical Geology/Paleontology” group, especially Prof. Dr. Helmut Willems,
Dr. Gerhard Versteegh, Maria, Nicole, Kara, Maike, Anne, Monika, Angelika,
Marion, Katarzyna, Stijn, Rehab, Ines, Sonja. Monika Kodrans-Nsiah is thanked for
all the fun we had at our office…I miss our Tee Pause. Thanks to all my friends and
colleagues, especially Jeroen, Heather, Cletus, Martin, Jörg, Chrsitian März (for the
Französich/Deutch/Spanish Tandem), Jean, Rosella, and Nourredine. Many thanks to
my dear friend Catalina González who always made me feel at home with her love,
support and patience. She was always my example of discipline, enthusiasm, and
passion for marine palynology. At the end, I would like to thank Igaratza Fraile for
the beautiful friendship and also for her support with all my problems that did not
regard Science.

I am immensely grateful to my parents for their permanent support and
encouragement during all my life and esepecially during these three years in
vi

distance. Vous étiez toujours présents et vous continuez de l’être pour faire mon
bonheur, je vous en suis très reconaissante. Merci d’être mes parents, j’en ai
toujours été fière et j’espère que vous l’êtes aussi de moi. Merci aussi à ma soeur
chérie, à l’unique soeur que j’ai au monde Mariam et à mon petit frère Bakr. Merci
d’être toujours à mes côtés. This thesis is dedicated to the memory of my beloved
grandfather who left us in December 2008. J’espère que, du monde qui est sien
maintenant, il accepte cet humble geste comme preuve de reconnaissance de la part
de sa petite fille qui a toujours apprécié son optimisme, sa générositè et sa joie de
vivre et qui a toujours prié pour le salut de son âme.

Most of all, I thank my “chèr fiancé” for his treasured love, without him my life and
work here in Bremen would not have been possible.

This work was funded by the German Research Foundation Deutsche
Forschungsgemeinschaft as part of the DFG-Research Center/Excellence cluster
“The Ocean in the Earth System”.

vii

Tableents of Cont

Acknowledgements...................................................................................................................................vi
Abstract......................................................................................................................................................1
Zusammenfassung.....................................................................................................................................4
Chapter 1 Introduction...............................................................................................................................7
1.1 Late Quaternary climatic fluctuations......................................................................................7
1.2 Marine palynology..................................................................................................................10
1.3 Scientific objectives................................................................................................................14
1.4 Outline....................................................................................................................................16
References..........................................................................................................................................18
Chapter 2 Environmental setting.............................................................................................................24
2.1 Regional climate.....................................................................................................................24
2.2 Oceanic circulation.................................................................................................................25
2.3 Senegal River..........................................................................................................................27
2.4 Regional vegetation and pollen sources.................................................................................27
References..........................................................................................................................................31
Chapter 3 Material and methods..............................................................................................................33
3.1 Marine sediment samples.......................................................................................................33
3.2 Radiocarbon dating.................................................................................................................33
3.3 Palynological processing........................................................................................................34
3.4 Statistical methods..................................................................................................................36
References..........................................................................................................................................38
Chapter 4 Dinoflagellate cyst distribution in marine surface sediments off West Africa (17 –
6°N) in relation to sea-surface conditions, freshwater input and seasonal coastal
upwelling......................................................................................................................................39
Abstract..............................................................................................................................................40
4.1 Introduction.............................................................................................................................41
4.2 Regional setting......................................................................................................................42
4.3 Material and Methods.............................................................................................................46
4.4 Results.....................................................................................................................................47
4.5 Discussion...................................................................................................