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Eolian Evidence for Spatial Variability of Late Quaternary Climates in Tropical Africa1

Published online by Cambridge University Press:  20 January 2017

Edward M. Pokras  and
Alan C. Mix
Edward M. Pokras
Affiliation:
Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York 10964
Alan C. Mix
Affiliation:
Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York 10964
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Abstract

Study of the eolian fraction of late Quaternary sediments from the tropical Atlantic reveals that two modes of long-term climate variability have existed in tropical Africa during the last 150,000 yr. Tropical northwest Africa (i.e., the southwestern Sahara and Sahel) was driest during glaciations and stades, but wetter than at present during interglaciations and interstades. This may be a response to ice sheets at higher latitudes, via equatorward displacement of the westerlies and the subtropical high. In contrast, central equatorial Africa (southeast of the Sahara) was most arid during interstades and times of ice growth, and most humid during deglaciation. Wet periods in this area correspond to insolation maxima in northern hemisphere summer. A 23,000-yr precessional rhythm is suggested, supporting a direct link between African Monsoon intensity and orbitally modulated insolation. The late Holocene is the only time observed when both areas are arid during an interglacial episode. This may reflect, in part, anthropogenic disturbance of late Holocene climates.

Type
Research Article
Information
Quaternary Research , Volume 24 , Issue 2 , July 1985 , pp. 137 - 149
Copyright
University of Washington

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Footnotes

1

Lamont-Doherty Geological Observatory, Contribution No. 3808.

References

Agwu, C.O.C. Beug, H.-J. (1982). Palnological studies of marine sediments off the West African coast “Meteor” Forschungs ergebnisse, Reihe C 36, 1–30 Google Scholar
Berger, A.L. (1978). Long-term variations of caloric insolation resulting from the Earth's orbital elements Quaternary Research 9, 139–167 CrossRefGoogle Scholar
Berger, W.H. Heath, G.R. (1968). Vertical mixing in pelagic sediments Journal of Marine Research 26, 134–142 Google Scholar
Charney, J.G. Stone, P.H. Quirk, W.J. (1975). Drought in the Sahara: A biogeophysical feedback mechanism Science (Washington, D.C.) 187, 434–435 CrossRefGoogle Scholar
Damuth, J.E. (1977). Late Quaternary sedimentation in the western equatorial Atlantic Geological Society of America Bulletin 88, 695–710 2.0.CO;2>CrossRefGoogle Scholar
Delany, A.C. Parkin, D.W. Griffin, J.J. Goldberg, E.D. Reimann, B.E.F. (1967). Airborne dust collected at Barbados Geochimica et Cosmochimica Acta 31, 885–909 CrossRefGoogle Scholar
Diester-Haass, L. Schrader, H.-J. Thiede, J. (1973). Sedimentological and paleoclimatological investigations of two pelagic ooze cores off Cape Barbas, Northwest Africa “Meteor” Forschungs Ergebnisse, Reihe C 16, 19–66 Google Scholar
Flight, C. (1976). The Kintampo culture and its place in the economic prehistory of West Africa Harlan, J.R. de Wet, J.M.J. Stemler, A.B.L. The Origins of African Plant Domestication Mouton The Hague 211–221 CrossRefGoogle Scholar
Flohn, H. (1966). Warum ist die Sahara trocken? Zeitschrift fur Meteorologie 17, 316–320 Google Scholar
Flohn, H. Nicholson, S. (1980). Climatic fluctuations in the arid belt of the “Old World” since the last glacial maximum: Possible causes and future implications Palaeoecology of Africa 12, 3–12 Google Scholar
Folger, D.W. Burckle, L.H. Heezen, B.C. (1967). Opal phytoliths in a North Atlantic dust fall Science (Washington, D.C.) 155, 1243–1244 CrossRefGoogle Scholar
Gasse, F. Talling, J.F. Kilham, P. (1983). Diatom assemblages in East Africa: Classification, distribution and ecology Revue d'Hydrobiologie Tropicale 16, 3–34 Google Scholar
Giresse, P. (1978). Le controle climatique de la sedimentation marine et continentale en Afrique central atlantique a la fin du Quaternaire—problemes de correlation Palaeogeography, Palaeoclimatology, Palaeoecology 23, 57–77 CrossRefGoogle Scholar
Harlan, J.R. (1982). The origins of indigenous African agriculture Clark, J.D. Cambridge History of Africa Vol. 1 Cambridge Univ. Press Cambridge 624–657 CrossRefGoogle Scholar
Imbrie, J. Hays, J.D. Martinson, D.G. McIntyre, A. Mix, A.C. Morley, J.J. Pisias, N.G. Prell, W.L. Shackleton, N.J. (1984). The orbital theory of Pleistocene climate: Support from a revised chronology of the marine δ18O record Berger, A.L. Imbrie, J. Hays, J. Kukla, G. Saltzman, B. Milankovitch and Climate Riedel Dordrecht 269–305 Part 1Google Scholar
Kalu, A.E. (1979). The African dust plume: Its characteristics and propagation across West Africa in winter Morales, C. Saharan Dust: Mobilization, Transport, Deposition Wiley Chichester 95–118 Google Scholar
Kolbe, R.W. (1957). Fresh-water diatoms from Atlantic deep-sea cores Science (Washington, D.C.) 126, 1053–1056 CrossRefGoogle Scholar
Kolla, V. Biscaye, P.E. Hanley, A.F. (1979). Distribution of quartz in late Quaternary Atlantic sediments in relation to climate Quaternary Research 11, 261–277 CrossRefGoogle Scholar
Kutzbach, J.E. (1981). Monsoon climate of the early Holocene: Climate experiment with the Earth's orbital parameters for 9000 years ago Science (Washington, D.C.) 214, 59–61 CrossRefGoogle ScholarPubMed
Maley, J. (1977). Analyses polliniques et paleoclimatologie des douze derniers millenaires du bassin du Tchad (Afrique centrale) Recherches francaises sur le Quaternaire INQUA. Association Francaises d'Etudes Quaternaires. 50, 187–197 supplement toGoogle Scholar
Melia, M.B. (1984). The distribution and relationship between palynomorphs in aerosols and deep-sea sediments off the coast of northwest Africa Marine Geology 58, 345–371 CrossRefGoogle Scholar
Mix, A. C. and Fairbanks, R. G. (in press). North Atlantic surface-ocean control of Pleistocene deep-ocean circulation. Earth and Planetary Science Letters .Google Scholar
Morley, J.J. (1977). Upper Pleistocene Climatic Variations in the South Atlantic Derived from a Quantitative Radiolarian Analysis: Accent on the Last 18,000 Years Ph.D. thesis Columbia University Google Scholar
National Research Council, (1983). Environmental Change in the West African Sahel U.S. Govt. Printing Office Washington, D.C Google Scholar
Newell, R.E. Kidson, J.W. (1984). African mean wind changes between Sahelian wet and dry periods Journal of Climatology 4, 27–33 CrossRefGoogle Scholar
Nicholson, S.E. (1982). Pleistocene and Holocene climates in Africa Nature (London) 296, 779–780 CrossRefGoogle Scholar
Nicholson, S.E. Flohn, H. (1980). African environmental and climatic changes and the general atmospheric circulation in the late Pleistocene and Holocene Climatic Change 2, 313–348 CrossRefGoogle Scholar
Parmenter, C. Folger, D.W. (1974). Eolian biogenic detritus in deep-sea sediments: A possible index of equatorial Ice Age aridity Science (Washington, D.C.) 185, 695–698 CrossRefGoogle ScholarPubMed
Pastouret, L. Chamley, H. Delibrias, G. Duplessy, J.-C. Thiede, J. (1978). Late Quaternary climatic changes in western tropical Africa deduced from deep-sea sedimentation off the Niger Delta Oceanologica Acta 1, 217–232 Google Scholar
Péwé, T.L. (1981). Desert dust: An overview Péwé, T.L. Desert Dust: Origin, Characteristics, and Effect of Man. Geological Society of America Special Paper. 186, 1–11 Google Scholar
Phillipson, D.W. (1982). Early food production in subSaharan Africa Clark, J.D. Cambridge History of Africa Vol. 1 Cambridge University Press Cambridge 770–829 CrossRefGoogle Scholar
Pokras, E.M. (1985). Paleoclimatic Investigation of Late Quaternary Diatoms from the Equatorial Atlantic Ph.D. thesis Columbia University Google Scholar
Prospero, J.M. (1981). Arid regions as sources of mineral aerosols in the marine environment Péwé, T.L. Desert Dust: Origin, Characteristics, and Effect of Man. Geological Society of America Special Paper. 186, 71–86 Google Scholar
Rossignol-Strick, M. (1983). African monsoons, an immediate climate response to orbital insolation Nature (London) 303, 46–49 CrossRefGoogle Scholar
Rossignol-Strick, M. Duzer, D. (1979). Late Quaternary pollen and dinoflagellate cysts in marine cores off West Africa “Meteor” Forschungsergebnisse, Reihe C 30, 1–14 Google Scholar
Ruddiman, W.F. McIntyre, A. (1976). Northeast Atlantic paleoclimatic changes over the last 600,000 years Cline, R.M. Hays, J.D. Investigation of Late Quaternary Paleoceanography and Paleoclimatology. Geological Society of America Memoir. 145, 199–214 Google Scholar
Sagan, C. Toon, O.B. Pollack, J.B. (1979). Anthropogenic albedo changes and the Earth's climate Science (Washington, D.C.) 206, 1363–1368 CrossRefGoogle ScholarPubMed
Sarnthein, M. (1978). Sand deserts during glacial maximum and climatic optimum Nature (London) 272, 43–46 CrossRefGoogle Scholar
Sarnthein, M. Erlenkeuser, H. Zahn, R. (1982). Termination I: The response of continental climate in the subtropics as recorded in deep-sea sediments Bulletin Institute Geologique du Bassin d'Aquitaine 31, 393–407 Google Scholar
Sarnthein, M. Koopmann, B. (1980). Late Quaternary deep-sea record of northwest African dust supply and wind circulation Palaeoecology of Africa 12, 239–253 Google Scholar
Sarnthein, M. Tetzlaff, G. Koopman, B. Wolter, K. Pflaumann, U. (1981). Glacial and interglacial wind regimes over the eastern subtropical Atlantic and north-west Africa Nature (London) 293, 193–196 CrossRefGoogle Scholar
Servant, M. Servant-Vildary, S. (1980). L'environnement quaternaire du bassin du Tchad Williams, M.A.J. Faure, H. The Sahara and the Nile A. A. Balkema Rotterdam 133–162 Google Scholar
Street, F.A. Grove, A.T. (1979). Global maps of lake-level fluctuations since 30,000 yr B.P. Quaternary Research 12, 83–118 CrossRefGoogle Scholar
Street-Perrott, F.A. Harrison, S.P. (1984). Temporal variations in lake levels since 30,000 yr B.P.—an index of the global hydrological cycle Hansen, J.E. Takahashi, T. Climate Processes and Climate Sensitivity American Geophysical Union Washington, D.C 118–129 CrossRefGoogle Scholar
Street-Perrott, F.A. Roberts, N. (1983). Fluctuations in closed-basin lakes as an indicator of past atmospheric circulation patterns Street-Perrott, F.A. Beran, M. Ratcliffe, R.A.S. Variations in the Global Water Budget Reidel Dordrecht 331–345 CrossRefGoogle Scholar
Talbot, M.R. (1980). Environmental responses to climatic change in the West African Sahel over the past 20,000 years Williams, M.A.J. Faure, H. The Sahara and the Nile A. A. Balkema Rotterdam 37–62 Google Scholar
Talbot, M.R. Hall, J.B. (1981). Further late Quaternary leaf fossils from Lake Bosumtwi, Ghana Palaeoecology of Africa 13, 83–92 Google Scholar
Tetzlaff, G. Wolter, K. (1980). Meteorological patterns and the transport of mineral dust from the North African continent Palaeoecology of Africa 12, 31–42 Google Scholar
Tetzlaff, G. Wolter, K. Sarnthein, M. (1982). Pleistocene and Holocene climates in Africa—Reply Nature (London) 296, 779–780 CrossRefGoogle Scholar
Thiede, J. (1977). Aspects of the variability of the glacial and interglacial North Atlantic boundary current (last 150,000 years) “Meteor” Forschungsergebnisse, Reihe C 28, 1–36 Google Scholar
Thompson, B.W. (1965). The Climate of Africa Oxford Univ. Press Nairobi Google Scholar
Twiss, P.C. Suess, E. Smith, R.M. (1969). Morphological classification of grass phytoliths Proceedings of the Soil Science Society of America 33, 109–115 CrossRefGoogle Scholar
Voice, M.E. Hunt, B.G. (1984). A study of the dynamics of drought initiation using a global general circulation model Journal of Geophysical Research 89/D6 9504–9520 CrossRefGoogle Scholar
Zachariasse, W.J. Schmidt, R.R. van Leeuwen, R.J.W. (1984). Distribution of foraminifera and calcareous nannoplankton in late Quaternary sediments of the eastern Angola Basin in response to climatic and oceanic fluctuations Netherlands Journal of Sea Research 17, 250–275 CrossRefGoogle Scholar