Open AccessMillennial‐scale northwest African droughts related to Heinrich events and Dansgaard‐Oeschger cycles: Evidence in marine sediments from offshore Senegal
Author(s) -
Itambi A. C.,
von Dobeneck T.,
Mulitza S.,
Bickert T.,
Heslop D.
Publication year - 2009
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2007pa001570
Subject(s) - stadial , geology , aeolian processes , glacial period , fluvial , oceanography , marine isotope stage , monsoon , intertropical convergence zone , contourite , interglacial , tropical atlantic , sediment , climatology , holocene , sea surface temperature , paleontology , precipitation , turbidite , physics , structural basin , meteorology
We present a suite of new high‐resolution records (0–135 ka) representing pulses of aeolian, fluvial, and biogenic sedimentation along the Senegalese continental margin. A multiproxy approach based on rock magnetic, element, and color data was applied on three cores enclosing the present‐day northern limit of the ITCZ. A strong episodic aeolian contribution driven by stronger winds and dry conditions and characterized by high hematite and goethite input was revealed north of 13°N. These millennial‐scale dust fluxes are synchronous with North Atlantic Heinrich stadials. Fluvial clay input driven by the West African monsoon predominates at 12°N and varies at Dansgaard‐Oeschger time scales while marine productivity is strongly enhanced during the African humid periods and marine isotope stage 5. From latitudinal signal variations, we deduce that the last glacial ITCZ summer position was located between core positions at 12°26′ and 13°40′N. Furthermore, this work also shows that submillennial periods of aridity over northwest Africa occurred more frequently and farther south than previously thought.