International Ocean Discovery Program (IODP) Expedition 361 drilled six sites on the southeast African margin and in the Indian-Atlantic ocean gateway, southwest Indian Ocean, from 30 January to 31 March 2016. In total, 5175 m of core was recovered, with an average recovery of 102%, during 29.7 days of on-site operations. The sites, situated in the Mozambique Channel at locations directly influenced by discharge from the Zambezi and Limpopo River catchments, the Natal Valley, the Agulhas Plateau, and Cape Basin, were targeted to reconstruct the history of the greater Agulhas Current system over the past ∼5 my. The Agulhas Current is the strongest western boundary current in the Southern Hemisphere, transporting some 70 Sv of warm, saline surface water from the tropical Indian Ocean along the East African margin to the tip of Africa. Exchanges of heat and moisture with the atmosphere influence southern African climates, including individual weather systems such as extratropical cyclone formation in the region and rainfall patterns. Recent ocean model and paleoceanographic data further point at a potential role of the Agulhas Current in controlling the strength and mode of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Pleistocene. Spillage of saline Agulhas water into the South Atlantic stimulates buoyancy anomalies that act as control mechanisms on the basin-wide AMOC, with implications for convective activity in the North Atlantic and global climate change. The main objectives of the expedition were to establish the sensitivity of the Agulhas Current to climatic changes during the Pliocene-Pleistocene, to determine the dynamics of the Indian-Atlantic gateway circulation during this time, to examine the connection of the Agulhas leakage and AMOC, and to address the influence of the Agulhas Current on African terrestrial climates and coincidences with human evolution. Additionally, the expedition set out to fulfill the needs of the Ancillary Project Letter, consisting of high-resolution interstitial water samples that will constrain the temperature and salinity profiles of the ocean during the Last Glacial Maximum. The expedition made major strides toward fulfilling each of these objectives. The recovered sequences allowed generation of complete spliced stratigraphic sections that span from 0 to between ∼0.13 and 7 Ma. This sediment will provide decadal- to millennial-scale climatic records that will allow answering the paleoceanographic and paleoclimatic questions set out in the drilling proposal.
Affiliation (analytic): Cardiff University, Department of Earth Sciences, Cardiff
Corporate Affiliation (monographic): International Ocean Discovery Program, Expedition 361 Scientists, College Station, TX
Coordinates: S311300 S311300 E0313243 E0313243; S412537 S412537 E0251538 E0251538; S154915 S154915 E0414607 E0414607; S192117 S192117 E0365454 E0365454; S254916 S254916 E0344610 E0344610; S350332 S350332 E0172404 E0172404
Contains 177 references
Research Program: IODP Integrated Ocean Drilling Program; IODP2 International Ocean Discovery Program
Document Type: Monograph
Bibliographic Level: Monograph
Source Note: Preliminary Report - International Ocean Discovery Program, Vol.361, 46p. Publisher: International Ocean Discovery Program, College Station, TX, United States. ISSN: 2372-9562
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute.
GeoRef ID: 2016051681
- Africa; Agulhas Current; Algae; Atlantic Meridional Overturning Circulation; Atlantic Ocean; Biostratigraphy; Cenozoic; Chemostratigraphy; Climate effects; Continental margin; Cores; Currents; Expedition 361; Foraminifera; IODP Site U1474; IODP Site U1475; IODP Site U1476; IODP Site U1477; IODP Site U1478; IODP Site U1479; Indian Ocean; International Ocean Discovery Program; Invertebrata; Last glacial maximum; Lithostratigraphy; Magnetostratigraphy; Marine sediments; Microfossils; Mozambique Channel; Nannofossils; Neogene; Ocean circulation; Ocean currents; Paleo-oceanography; Paleoclimatology; Paleomagnetism; Physical properties; Plantae; Pleistocene; Pliocene; Protista; Quaternary; Sediments; South Atlantic; Southeast Atlantic; Southern Africa; Tertiary
- 12 Stratigraphy, Historical Geology and Paleoecology