Schefuss, Enno et al. (2005): Tropical environmental changes at the mid-Pleistocene transition; insights from lipid biomarkers

Leg/Site/Hole:
ODP 111
ODP 175
ODP 175 1077
ODP 111 677
Identifier:
2006-031594
georefid

Creator:
Schefuss, Enno
Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry Department, Woods Hole, MA, United States
author

Jansen, J. H. F.
Royal Netherlands Institute for Sea Research, Netherlands
author

Sinninghe Damste, Jaap S.
author

Identification:
Tropical environmental changes at the mid-Pleistocene transition; insights from lipid biomarkers
2005
In: Head, Martin J. (editor), Gibbard, Philip L. (editor), Early-middle Pleistocene transitions; the land-ocean evidence
Geological Society of London, London, United Kingdom
247
35-64
Mid-Pleistocene (1250-450 ka) lipid biomarker accumulation rates and bulk organic geochemical records have been examined from the Angola Basin in the eastern tropical Atlantic to assess the low-latitude environmental changes associated with the onset of the Middle Pleistocene ice ages. In combination with information on lipid sources, we use principal component and spectral analyses to evaluate the main forcing factors of phytoplankton productivity and lipid transport changes. Cross-spectral analyses reveal the phasing in orbitally driven climatic cycles. The average export of marine productivity remained high and unchanged throughout the mid-Pleistocene transition. However, the relative lipid contributions indicate a significant change in the primary-producing ecosystem. Before the growth of mean global ice volume, enhanced siliceous marine production was mainly controlled by monsoonal variations in river runoff, and oceanic upwelling was forced by variations in trade wind zonality. Both precession-driven processes were suppressed by the enlarged global ice mass after the beginning of the mid-Pleistocene transition. With the onset of 100 ka cyclicity, aeolian transport of terrigenous plant waxes and wind-driven coastal and oceanic upwelling strongly increased. From this time onwards, aridification of the continent and strengthening of the trade winds caused profound environmental changes in the tropical realm.
English
Coverage:Geographic coordinates:
North:1.1209
West:-83.4414East: 10.2611
South:-5.1048

Quaternary geology; Isotope geochemistry; Angola Basin; Atlantic Ocean; biomarkers; C-13/C-12; carbon; Cenozoic; chemostratigraphy; climate change; climate forcing; cores; cycles; cyclic processes; diagenesis; East Atlantic; East Pacific; Equatorial Atlantic; Equatorial Pacific; fatty acids; Foraminifera; geochemistry; glacial environment; global change; interglacial environment; Invertebrata; isotope ratios; isotopes; Leg 111; Leg 175; lipids; lower Pleistocene; marine sediments; microfossils; middle Pleistocene; O-18/O-16; obliquity of the ecliptic; Ocean Drilling Program; ODP Site 1077; ODP Site 677; orbital forcing; organic acids; organic compounds; oxygen; Pacific Ocean; paleoclimatology; paleoenvironment; Pleistocene; precession; principal components analysis; productivity; Protista; Quaternary; sedimentation; sedimentation rates; sediments; South Atlantic; spectra; stable isotopes; statistical analysis; terrigenous materials; total organic carbon; tropical environment;

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