Publication Date:
2024-02-02
Description:
The rapidity and synchrony of the African Humid Period (AHP) termination at around 5.5 ka are debated, and it is unclear what caused a rapid hydroclimate response. Here we analyzed the hydrogen isotopic composition of sedimentary leaf-waxes (dDwax) from the Gulf of Guinea, a proxy for regional precipitation in Cameroon and the central Sahel-Sahara. Our record indicates high precipitation during the AHP followed by a rapid decrease at 5.8-4.7 ka. The similarity with a dDwax record from northern East Africa suggests a large-scale atmospheric mechanism. We show that northern high- and mid-latitude cooling weakened the Tropical Easterly Jet and, through feedbacks, strengthened the African Easterly Jet. The associated decrease in precipitation triggered the AHP termination and combined with biogeophysical feedbacks to result in aridification. Our findings suggest that extratropical temperature changes, albeit smaller than during the glacial and deglacial, were important in triggering rapid African aridification during the Holocene.
Keywords:
AGE; Age, AMS 14C, BACON 2.2; Center for Marine Environmental Sciences; DEPTH, sediment/rock; Gas chromatography - Isotope ratio mass spectrometer (GC-IRMS); GeoB; GeoB4905-4; Geosciences, University of Bremen; Gravity corer (Kiel type); M41/1; MARUM; Mass spectrometer Finnigan MAT 252; Meteor (1986); n-Alkane C29, δ13C; n-Alkane C29, δ13C, standard deviation; n-Alkane C29, δD; n-Alkane C29, δD, standard deviation; n-Alkane C31, δ13C; n-Alkane C31, δ13C, standard deviation; n-Alkane C31, δD; n-Alkane C31, δD, standard deviation; off Cameroon; Quantile; SL
Type:
Dataset
Format:
text/tab-separated-values, 4487 data points
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