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Paleoenvironmental signatures of aeolian and fluvial sedimentary end-members off NW Africa

Paleoenvironmental signatures of aeolian and fluvial sedimentary end-members off NW Africa

Chapter 2 - Unmixing signatures of aeolian, fluvial, bacterial and diagenec magnec mineral fracons in Late Quaternary marine sediments off Gambia, NW Africa 13 2.1 Introducon 2.2 Geologica[r]

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The Senegal mud-belt depocenter (NW-Africa) - an archive for climatic changes, coastal dynamics and shelf organization over the Holocene -

The Senegal mud-belt depocenter (NW-Africa) - an archive for climatic changes, coastal dynamics and shelf organization over the Holocene -

Fine-grained sediment depocenters on continental shelves are of increased scientific interest since they represent highly-valuable archives of climate and coastal development. A NS- elongated mud depocenter extends along the Senegalese coast in mid-shelf position. Shallow- acoustic profiling was carried out to determine extent, geometry and internal structures of this sedimentary body. In addition, core-top ages were used to reconstruct the sub-recent depositional evolution of this mud depocenter. The Senegal mud belt is a layered inhomogeneous sedimentary body deposited on an irregular erosive surface. Close to the coast, an aggradational pattern is displayed, which then transforms seaward into a prograding pattern. The mud belt is composed of two main acoustic units which were identified based on their acoustic facies and sedimentary architecture. In the North, a chaotic acoustic unit (unit 1) drapes on the mud belt basal reflector. This unit was interpreted as the result of reworking processes on previously deposited coarse fluvial material by waves during the early flooding of the shelf. The second unit (unit 2) situated above unit 1 in the North and above the mud belt basal reflector in the South, displays from its acoustic facies and architecture a clear change in sedimentation. Unit 2 is defined as a body of weak and diffuse internal reflection with parallel internal horizons. This change in sedimentation is attributed to an Early Holocene deceleration in the rate of the sea-level rise allowing mud deposition on the shelf. These favorable conditions for mud deposition occur coevally with a humid period, thus, high river discharge over NW-Africa. Sedimentation has started preferentially in the northern areas of the mud belt. Then, an interruption of sedimentation in the North, associated with a southward shift in the location of the depocenters is observed in the sedimentary architecture. This is also confirmed by the core-top dates. These sub-recent shifts in depocenters location are caused by migrations of the Senegal River mouth. Presence of free gas in the sediment was inferred by the occurrence of acoustic blanking and enhanced reflection phenomena. In the northern regions of the mud belt, the presence of free gas in a topographic low might indicate the occurrence of a buried lagoonal or fluvial depression on the shelf.
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Holocene climate trends in NW Africa: Inferences from grain-size distributions of terrigenous sediments and isotopic provenance studies

Holocene climate trends in NW Africa: Inferences from grain-size distributions of terrigenous sediments and isotopic provenance studies

from the African continent, which was used to study the variable continent-ocean dynamics between sediment transport processes in the proximal marine environments off NW Africa and the e[r]

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Reconstruction of the sedimentary history offshore NW Africa: Application of core-logging tools

Reconstruction of the sedimentary history offshore NW Africa: Application of core-logging tools

Manuscript 2 (chapter 5) focuses on the interaction of climatic systems in northern NW Africa and their impact on the terrigeneous contribution to the marine sediments. Although previous studies discussed eolian dust as the main contributor of lithogenic material, this study has determined that riverine input is also an important transport mechanism, particularly in coastal areas with a mountainous hinterland receiving significant precipitation. As a basis for this interpretation, high-resolution Fe distribution is presented as an indicator for terrigeneous input. To achieve the broadest basis for a calibration of the XRF Core Scanner data into elemental concentrations as much geochemical data as available were included. This is documented by the large number of co-authors of the corresponding manuscript: “Meridional shifts of the Mediterranean and monsoonal climate system off NW Africa during the last 130,000 years: implications from river discharge.”, by Kuhlmann, H., Meggers, H., Moreno, A., Freudenthal, T., Kasten, S., Hensen, C., and von Oppen, C. (submitted to Quaternary Research). Dr. A. Moreno provided XRF data measured on discrete sediment samples. Dr. S. Kasten and Dr. C. Hensen supplied ICP-AES data and C. von Oppen provided AAS data. These data are used for the calibration of the XRF Scanner-derived cps into concentrations. Dr. T. Freudenthal and Dr. H. Meggers provided the age models of stratigraphic reference cores.
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Climate and sea level controlled sedimentation processes in two submarine canyons off NW-Africa

Climate and sea level controlled sedimentation processes in two submarine canyons off NW-Africa

the northward shift of the ITCZ (20°N during August) is accompanied by the humid “SW” monsoon south of the ITCZ. Northeast directed trade winds prevail during winter times when the ITCZ has migrated to the southward position of 5°N. The trade winds and the overlying Sahara Air Layer are the prevailing wind systems over NW-Africa (Fig. 1a) and drive major dust transport from the Sahara-Sahel zone towards the Atlantic Ocean (Koopmann, 1981; Prospero and Lamb, 2003). Fluvial supply in the study area is restricted to the Senegal River north of Dakar but plays only a minor role in sediment supply (Redois and Debenay, 1999). Therefore, the surface sediments on the Senegalese shelf consist of quartz sands and carbonate shell fragments (McMaster and Lachance, 1969; Barusseau et al., 1988; Redois and Debenay, 1999). These sands have originated from palaeo-dunes that, in turn, have formed around the Last Glacial Maximum (LGM) as a result of increased aridity and wind strength (Sarnthein and Diester-Haass, 1977; Lancaster et al., 2002), and low sea level providing widely exposed shelf areas. The Senegalese Shelf varies in width between 50 - 100 km (Hagen, 2001) and the average depth of the shelf break south of 15°N is found in about 100 - 150 m present water depths (McMaster and Lachance, 1969).
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Seasonal dynamics and characterizationof coccolithophore export productionin two major upwelling regions:Cape Blanc (NW-Africa)&Chile (30 degrees S)

Seasonal dynamics and characterizationof coccolithophore export productionin two major upwelling regions:Cape Blanc (NW-Africa)&Chile (30 degrees S)

Interannual variability induced by reoccurring hydrographic/climatic conditions as the El Niño–Southern Oscillation (ENSO) phenomenon gives the opportunity in combination with sediment trapping to study the development and the resulting effects to the existing phy- toplankton community and in particular to the coccolithophores (De Bernardia et al., 2005). The seasonal export pattern of different phytoplankton groups and their interaction or re- lationship to coccolithophores was infrequently a further focus of former studies (Beaufort and Heussner, 1999; Jickells et al., 1996; Romero et al., 2002a). In general, the ef ciency of the biological carbon pump is dictated by the composition of the phytoplankton. Consequently, the impact of primary production on marine (geo-)chemistry strongly depends on the spe- cies of phytoplankton that photosynthesize (Dandonneau et al., 2004). In upwelling regions the plankton community is dominated by diatoms (Romero, 1998), whereas high numbers of coccolithophores usually occur besides the primary upwelling centres in waters with low silica content (Giraudeau et al., 1993). Within the phytoplankton succession observed in up- welling areas, they often follow blooms of diatoms, when the photic zone becomes depleted in silica and starts to stratify (Giraudeau and Bailey, 1995; Mitchell-Innes and Winter, 1987). Further, these aspects are of importance since they display the basic parameter for modelling future development of phytoplankton communities and their implication for global climate (change) (Gregg and Casey, 2007). First attempts of modelling coccolithophore and further phytoplankton groups have been made for NW-Africa (Giraud, 2006) and the Black Sea (Oguz and Merico, 2006).
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Research universities in Africa

Research universities in Africa

Discussions of university performance in the post-independence period in sub-Saharan Africa have often been dominated by perspectives that emphasise the ineffectiveness of African states (see Evans & Rauch 1999), and the idea of ‘African exceptionalism’ – that is, the notion that the continent constitutes a special case to which the standards for analysis elsewhere cannot be applied. In relation to the latter, some scholars have considered models for examining university performance in the OECD states applicable to developing countries in (East) Asia and Latin America, but less relevant to those in Africa. Such exceptionalism is arguably justified by a lack of available data or experts, or assumed differences in governance challenges and institutional formation in sub-Saharan Africa. For example, Altbach and Balán (2007) elected not to include Africa in their discussion of the transformation of research universities in Asia and Latin America in their book, World Class Worldwide. They justified the continent’s exclusion on the basis that it faced greatly different academic challenges from those encountered in Latin America and Asia without providing any empirical evidence for this omission (Altbach & Balán 2007: vii).
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India's Africa policy

India's Africa policy

As regards regional issues, India and Germany also have a number of common interests. First, the Indian Ocean is of great strategic importance to both. As a leading trading nation, Germany has an overriding interest in secure world trade, the main routes of which include the Indian Ocean. The threat to the sea lanes of communication posed by pirates, for instance off the Horn of Africa, or a race for geostrategic zones of influence in the region thus directly affect German and European interests. The same applies to India, which wants to increase its influence in the global economy. Furthermore, India is highly dependent on energy imports from the Middle East and Africa and thus also depends on safe shipping routes in the In- dian Ocean. For several years, India has been pur- suing a policy of security partnership with Indian Ocean island states so as to counter China’s growing involvement in the region.
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“Born in Africa but...”

“Born in Africa but...”

This study concentrates on South African poetry written in English, even though a number of South Africans believe that the African languages and Afrikaans are more suited to poetry than English. Amongst these is Robert Berold, an expert on poetry who says that, compared to Afrikaans, “English […] is not so resonantly written. That is changing slowly as Africa breathes into it, but it’s still relentlessly flat, the language of commerce and politics”, 259 to which the poet Karen Press adds: “…and of polite cowardice”. 260 Yet, even though Afrikaans used to have its own, stable readership due to the numerous and famous Afrikaans poets and their poetry, according to Anthea Garman, even poets like Antjie Krog are “pragmatically conscious that [English] has greater reach and acceptability both in South Africa and internationally”. 261 Poets like her, therefore, have started to write in or translate their poetry into English to make it accessible to a wider audience and to additional markets: “I longed to interact as a poet with South Africans who do not read Afrikaans – in the same way that I was communicating with an enthusiastic Afrikaans audience”. 262 In the acknowledgments to Body Bereft, 263 Antjie Krog states that, as a solution, to feel integrated with her poems published in English, all are first written in Afrikaans and later translated “keeping the underlying Afrikaans structure and rhythm intact”. She further notes that the translations “sometimes [differ] from the original Afrikaans in content and/or form”. 264 For this reason, as well as for the fact that “the idiosyncratic – and well known – voice that Krog has cultivated as a poet is strongly evident in the text”, 265 I consider her English versions to be on an equal plane to her Afrikaans poetry, and they are therefore included in this study.
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Active tectonics of the Lower Rhine Graben
(NW Central Europe)

Active tectonics of the Lower Rhine Graben (NW Central Europe)

The NE-most scarp of the study area (Erft-scarp 1, Figure 3.7) represents the edge of the Early Pleistocene Rhine River terrace (Jüngere Hauptterasse) and is not associated with tectonic activity (Klostermann, 1992; Quitzow, 1956; Winter, 1970). Eastward incision of the scarp, however, most likely results from tectonically induced base-level-drop, and headward erosion along the Viersener fault, which represents the easternmost rift structure of the Lower Rhine Graben (Ahorner, 1962; Fliegel, 1922; Quitzow and Vahlensieck, 1955). Erft scarp 2 (Figure 3.7) is the surface expression of the Erft fault, one of the major boundary faults of the Lower Rhine Graben (Ahorner, 1962; Strecker et al., 2002; Streich, 2003), which offsets the Erft block to the SW against the Ville Horst to the NE. The increase of scarp height towards the NW is in accordance with the displacement of Tertiary and Quaternary strata, which also increases towards the NW along the Erft fault (Ahorner, 1962; Quitzow and Vahlensieck, 1955). According to the geological map of the area (von Kamp, 1987), as well as former tectonic studies (Ahorner, 1962; Quitzow and Vahlensieck, 1955), Erft-scarp 3 is the surface expression of the NW-SE striking Swist fault, the southernmost segment of the Erft fault system (Figure 3.8). At the study site, the fault scarp is intensively eroded and overprinted by the meandering Swist Creek, which strongly hampers the recognition of the tectonic origin of this scarp.
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Diageneseevolution von Ober-Rotliegend II Sandsteinen eines Tight-Gas Feldes in Ostfriesland (NW Deutschland)

Diageneseevolution von Ober-Rotliegend II Sandsteinen eines Tight-Gas Feldes in Ostfriesland (NW Deutschland)

Von den Bohrungen 2 und 3 wurden jeweils zwei Bohrkernstücke von Rotliegend- Sandsteinproben für die K-Ar-Altersdatierung gewählt, die nach Daten von Gaupp (1998) je Probe nu[r]

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Zum Einfluss von Witterung und Klima auf den Landschaftszustand und die Landschaftsentwicklung im Uvs-Nuur-Becken (NW-Mongolei)

Zum Einfluss von Witterung und Klima auf den Landschaftszustand und die Landschaftsentwicklung im Uvs-Nuur-Becken (NW-Mongolei)

Ihre inhaltliche Kennzeich- nung stützt sich sowohl auf die Parameter, die direkt in die Clusterung nach dem Average- Linkage-Verfahren eingegangen sind (Globalstrahlung, Lufttemperatur [r]

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Honey bee network in Africa co-creating a grassroots innovation ecosystem in Africa

Honey bee network in Africa co-creating a grassroots innovation ecosystem in Africa

precarious nature of the knowledge system in Kenya.    The basic building blocks of the innovation ecosystem are spontaneous problem‐solving attempts by  local communities. 19  There is an institution under the National Museums of Kenya (NMK), the Kenya  Resource  Centre  for  Indigenous  Knowledge  (KENRIK),  which  is  tasked  with  the  conservation  of  indigenous  knowledge.  KENRIK  helped  associate  the  scientific  names  of  these  plants  to  their  Maa  language  names  and  played  an  organizing  role.  The  institution  has  collected  over  2000  traditional  practices and has a database of medicinal plants in the region. Currently, the Centre has only six people  and is facing budget cuts. Such institutions can be tasked with kick‐starting the innovation ecosystem  in Africa 20 . Similarly, institutions in other East African countries can collaborate to start building a larger 
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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

Liebe Leserinnen und Leser von AFRICA live, beinahe täglich lesen wir in der deut- schen und internationalen Presse über die humanitäre Katastrophe, die sich in der westsudanesischen Provinz Darfur ab- spielt. Darfur ist mittlerweile zum Inbe- griff für Gräueltaten auf dem afrikani- schen Kontinent avanciert und wird in ei- nem Atemzug mit dem Völkermord in Ruanda genannt. Nicht noch ein «zweites Ruanda» fordert deshalb auch UN-Gene- ralsekretär Kofi Annan und will mit einer verstärkten UN-Blauhelmtruppe der Afri- kanischen Union (AU) in Darfur zu Hilfe kommen. «Afrikanische Lösungen für afri- kanische Probleme» so lautete der Leitsatz der internationalen Gemeinschaft für Darfur. 7000 afrikanische Soldaten versu- chen in der Westprovinz das Schlimmste zu verhindern. Doch die AU-Truppen ste- hen auf schwierigem Posten gegenüber ri- valisierenden Rebellengruppen und den Milizen der Regierung, den Dschandscha- wid. Ihnen fehlt es vor allem an der Fi- nanzierung, der technischen und logisti- schen Kapazität – und auch an einem ent- sprechend robusten Mandat, was in der Diskussion häufig vergessen wird. Bisher kamen mindestens 200.000 Menschen ums Leben, über zwei Millionen wurden aus ihren Dörfern vertrieben. Andere Zah- len gehen von noch mehr Opfern aus, ge- naue Angaben gibt es nicht.
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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

Mounir Bensaid, Leiter der marokkani- schen Exportförderungsagentur, gegenü- ber Africa live: «Wir haben 40 Jahre lang an der Grünen Woche teilgenommen, sind dafür sogar ausgezeichnet wo[r]

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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

Wenn jemand viele Bücher ge- lesen hat und denkt, ich wäre primitiv, nur weil ich noch kein einziges gelesen habe, dann sollte er all diese Bücher wegwerfen und sich eines be- sorgen, da[r]

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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

Jetzt sind die Veranstalter am Ball, sie müssen ihre Hausaufgaben machen und dafür sorgen, dass fürs nächste Mal eine perfekte Organisation verbindlich zugesagt wird, damit diese auch vo[r]

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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

Und dann brachte er noch eine ganz gewagte These aufs Tapet: «Es sind zwar enorme Investitionen erforderlich, die sich erst in einigen Jahren amortisieren werden, aber dann werden wir du[r]

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Africa-live.de - das Afrika-Portal:

Africa-live.de - das Afrika-Portal:

tem Maße dafür zu sorgen, dass Gefährdete in Sicherheit gebracht werden. Die EUFOR hält sich somit bereit, die UNO-Mission, deren Oberbe- fehlshaber ich bin, mit zu tra- gen. Es muss jed[r]

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Africa and climate change: Can Africa manage on its own?

Africa and climate change: Can Africa manage on its own?

Suggested Citation: Wiebelt, Manfred (2011) : Africa and climate change: Can Africa manage on its own?, In: Natalia Trofimenko (Ed.): Climate Change: Current Issues, Kiel Institute for the World Economy, Kiel, pp. 22-23 This Version is available at: http://hdl.handle.net/10419/60985

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