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deMenocal et al. 1993
deMenocal, P.B., Ruddiman, W.F. and Pokras, E.M. (1993). Influences of high- and low-latitude processes on African terrestrial climate: Pleistocene eolian records from equatorial Atlantic Ocean drilling program site 663. Paleoceanography 8: doi: 10.1029/93PA02688. issn: 0883-8305.

High- and low-latitude forcing of terrestrial African paleoclimate variability is demonstrated using 900 ka eolian and biogenic component records from Ocean Drilling Program site 663 in the eastern equatorial Atlantic. Terrigenous (eolian dust) and phytolith (savannah grass cuticle) accumulation rate records vary predominantly at 100 and 41 kyr periodicities and spectral phase estimates implicate high-latitutde forcing. The abundance of freshwater diatoms (Melosira) transported from dry African lake beds varies coherently at 23-19 kyr orbital periodicities and at a phasing which implicates low-latitude precessional monsoon forcing. Modeling studies demonstrate that African climate is sensitive to both high- and low-latitude boundary conditions. African monsoon intensity is modulated by direct insolation variations due to orbital precession, whereas remote high-latitude forcing can be related to cool North Atlantic sea surface temperatures (SSTs) which promote African aridity and enhance dust-transporting wind speeds. The site 663 terrigenous and phytolith records covary with North Atlantic SST variability at 41 ¿N (site 607). We suggest that Pleistocene African climate has responded to both high-latitude North Atlantic SST variability as well as low-latitude precessional monsoon forcing; the high-latitude influence dominates the sedimentary record. Prior to circa 2.4 Ma, terrigenous variations occurred primarily at precessional periodicities (23-19 kyr), indicating that African climate was largely controlled by low-latitude insolation variations prior to the onset of high-ampitude glacial-interglacial climate change. ¿ American Geophysical Union 1993

BACKGROUND DATA FILES

Abstract

Keywords
Oceanography, General, Paleoceanography, Oceanography, General, Climate and interannual variability, Information Related to Geologic Time, Cenozoic, Information Related to Geographic Region, Atlantic Ocean
Journal
Paleoceanography
Publisher
American Geophysical Union
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