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Mienert, Jürgen (1986): Physical and acoustic sediment properties of sediment cores from the eastern equatorial Atlantic [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.548491, Supplement to: Mienert, J (1986): Akustostratigraphie im äquatorialen Ostatlantik: Zur Entwicklung der Tiefenwasserzirkulation der letzten 3,5 Millionen Jahre. Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C40, 19-86

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Abstract:
To reconstruct the deep-water circulation for the last 3.5 Ma from deep-sea sediments of the eastern equatorial Atlantic, sea floor morphology, sub-bottom reflectors and the echo character have been mapped on the basis of 3.5 kHz records and sediment cores.
Physical properties of sediments and synthetic seismograms derived from them enable us to decipher reflector sequences in environments of pelagic, current-resuspended and turbidity sedimentation. The individual reflectors originate from carbonate dissolution, hiatus, coarse sand layers and interferences. Those which are related to carbonate dissolution and hiatus provide evidence of water-mass boundaries by their distribution.
Five phases of different deep-water circulation can be seen in the record of th elast 3.5 Ma, and these are related to climate history:
1. Between 3.7 Ma and 2.2 Ma a strong deep-water circulation indicates a northward flow of bottom water below 4200 m (AABW = Antarctic-Bottom Water) and a southward flow of deep-water above 4200 m (NADW = North-Atlantic Deep Water).
2. Between 1.6 and 1.4 Ma a southward flow of bottom water below 4500 m and a diminished southward flow above 4500 m can be detected. This water-mass geometry can be interpreted by an expansion of the NADW-masses and a displacement of the AABW-masses during the same time.
3. Since 1.4 Ma a northward flow of a bottom-water current developed again. This current flow created a leeside sediment ridge in the southern part of the Kane Gap and furrows in the northern part of it.
4. Between 400,000 and 200,000 yrs B. P. the oceanic and atmospheric circulation increased. The strengthened oceanic circulation caused and increase in carbonate dissolution, which is documented by a traceable reflector from 2800 m to 4500 m water depth. At the same time an increase of the atmospheric circulation caused a drastic rise in the pelagic sediment accumulation (> 100 %) through an intensification of upwelling. This runs parallel with a higher oceanic productivity in the northern equatorial divergence zone and an enhanced supply of fluvial and probably eolian sediments from the Senegal and Guinea.
5. Before 10,000 yrs B. P. an erosive northward flowing bottom-water current prevailed below 4500 m water depth. After 10,000 yrs B.P. the bottom-water flow was sluggish and non erosive.
Project(s):
Institute for Geosciences, Christian Albrechts University, Kiel (GIK/IfG)
Coverage:
Median Latitude: 9.836145 * Median Longitude: -20.124999 * South-bound Latitude: 3.020000 * West-bound Longitude: -22.031660 * North-bound Latitude: 14.788333 * East-bound Longitude: -19.008333
Date/Time Start: 1975-01-01T00:00:00 * Date/Time End: 1983-08-09T00:00:00
Event(s):
GIK13521-1 * Latitude: 3.020000 * Longitude: -22.031660 * Date/Time: 1975-01-01T00:00:00 * Elevation Start: -4504.0 m * Elevation End: 0.0 m * Recovery: 9.3 m * Location: Atlantic Ocean * Campaign: M39 * Basis: Meteor (1964) * Method/Device: Gravity corer (Kiel type) (SL)
GIK16401-4 * Latitude: 14.788333 * Longitude: -20.520000 * Date/Time: 1983-07-09T00:00:00 * Elevation: -4148.0 m * Location: Atlantic Ocean * Campaign: M65 (GEOTROPEX 83, NOAMP I) * Basis: Meteor (1964) * Method/Device: Kasten corer (KAL)
GIK16402-2 * Latitude: 14.458330 * Longitude: -20.541660 * Date/Time: 1983-07-12T00:00:00 * Elevation Start: -4234.0 m * Elevation End: 0.0 m * Location: Atlantic Ocean * Campaign: M65 (GEOTROPEX 83, NOAMP I) * Basis: Meteor (1964) * Method/Device: Gravity corer (Kiel type) (SL) * Comment: offset to GIK16402-1 = 10.5 cm
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
16 datasets

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Datasets listed in this publication series

  1. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK13521-1, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544624
  2. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16401-4, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544625
  3. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16402-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544626
  4. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16404-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544627
  5. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16406-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544628
  6. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16408-5, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544629
  7. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16410-3, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544630
  8. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16412-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544631
  9. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16414-1, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544633
  10. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16415-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544634
  11. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16416-2, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544635
  12. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16422-3, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544636
  13. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16423-1, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544637
  14. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16424-3, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544638
  15. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16425-4, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544639
  16. Mienert, J (1986): Physical and acoustic sediment properties of sediment core GIK16425-5, eastern equatorial Atlantic (Table 7). https://doi.org/10.1594/PANGAEA.544640