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Clay mineralogy and organic carbon content of sediment core GeoB1401-4

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.729719
Keywords
  • Age Model
  • Calculated Ages
  • Carbon
  • Organic
  • Total
  • Chl
  • Chlorite
  • Congo Fan
  • Element Analyser Chn
  • Leco
  • Geob
  • Geob1401-4
  • Geosciences
  • University Of Bremen
  • Gravity Corer (Kiel Type)
  • Ill
  • Ill Ei
  • Ill Hhw Glyc
  • Illite
  • Illite 5Å/10Å Esquevin-Index
  • Illite Half Height Width
  • Glycolized
  • Kaolinite
  • Kln
  • M16/1
  • Meteor (1986)
  • Sme
  • Smectite
  • Smectite (Half Height Width)
  • Sme Hhw
  • Toc
  • X-Ray Diffraction Textur
  • Clay Fraction
Disciplines
  • Chemistry

Abstract

Late Quaternary sediments recovered in a core from the area of the Zaire Fan, Central Africa, were analyzed for clay mineral composition in order to reconstruct fluctuations in the sediment input and freshwater discharge of the Zaire River. Clay mineral assemblages are dominated by kaolinite and smectite, which both originate mainly from the Zaire River and contain only minor contributions of eolian dust. Smectite crystallinity and chemical character of illites (Fe, Mg- or Al-rich) are used to track sediment input from the Zaire River and assess fluctuations in the freshwater discharge. Both parameters record a high-latitude forcing of river runoff at 100 ka periodicities reflecting glacial aridity and increased runoff during interglacials 1, 5 and 7. This signal is also observed in kaolinite/smectite ratios which represent the extension and intensity of the freshwater plume of the Zaire River. Clay mineral proxies reveal that river discharge and associated sediment input fluctuated in tune with precessional cycles of African monsoon intensity. Increased eolian input of kaolinite-rich dust with intensified northeast trades during glacials flattens the precessional signal in kaolinite/smectite ratios.

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