During African Humid Period in the Holocene when the summer Intertropical Convergence Zone migrated to its northernmost position, the Qarun Lake in the Faiyum Oasis in Egypt was fed with regular inflows from the Nile River and rainfall brought by the Mediterranean winter circulation. Finely-laminated lake sediments, dated at 8.5-6.7 cal kyr B.P., were examined in terms of lithology, geochemistry, microfossils (diatom, pollen) and magnetic susceptibility. Based on the inferred geographical derivation of pollen, the environmental affiliation of diatom taxa and geochemistry of lake sediments, wind trajectories were distinguished, related to two main atmospheric circulation phases. During the earlier phase (8.50-7.83 cal kyr B.P.) there were northwestern wind trajectories followed by southern ones and during the later phase (7.83-6.70 cal kyr B.P.), the northern winds were followed by northwestern and southern ones. Northwestern and northern winds brought winter rainfall and caused water turbulence in the lake, and the southern winds were associated with regional aridification. This scenario of atmospheric circulation in northeastern Africa extends significantly our understanding of key modes of climatic variability and wind trajectories in the Early to Middle Holocene (Greenlandian to Northgrippian) transition.
1.Univ Warsaw, Fac Geol, Warsaw, Poland 2.Cardinal Stefan Wyszynski Univ, Inst Archaeol, Warsaw, Poland 3.Adam Mickiewicz Univ, Dept Biogeog & Paleoecol, Poznan, Poland 4.Tanta Univ, Fac Sci, Tanta, Egypt 5.East China Normal Univ, State Key Lab Estuarine & Coastal Res, Shanghai 200062, Peoples R China 6.John Paul 2nd State Higher Sch, Fac Econ & Tech Sci, Biala Podlaska, Poland 7.Kafrelsheikh Univ, Fac Sci, Kafrelsheikh, Egypt
Recommended Citation:
Marks, Leszek,Welc, Fabian,Milecka, Krystyna,et al. Cyclonic activity over northeastern Africa at 8.5-6.7 cal kyr BP, based on lacustrine records in the Faiyum Oasis, Egypt[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2019-01-01,528:120-132