Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic
High-resolution analyses of sediments at equatorial Atlantic Sites 662, 663, and 664 define the accumulation rates of biogenically produced CaC03 and opal and of eolian dust from North Africa over the last 3.7 m.y. The mean flux of opal increased abruptly by 60%-70% near 2.5 Ma (2.65 to 2.3 Ma), ref...
Main Authors: | , |
---|---|
Format: | Other/Unknown Material |
Language: | English |
Published: |
PANGAEA
1989
|
Subjects: | |
Online Access: | https://doi.pangaea.de/10.1594/PANGAEA.746239 https://doi.org/10.1594/PANGAEA.746239 |
id |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.746239 |
---|---|
record_format |
openpolar |
spelling |
ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.746239 2024-09-15T18:24:11+00:00 Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic Ruddiman, William F Janecek, Thomas R MEDIAN LATITUDE: -0.693789 * MEDIAN LONGITUDE: -16.636249 * SOUTH-BOUND LATITUDE: -1.390200 * WEST-BOUND LONGITUDE: -23.227500 * NORTH-BOUND LATITUDE: 0.107300 * EAST-BOUND LONGITUDE: -11.739200 * DATE/TIME START: 1986-03-24T03:00:00 * DATE/TIME END: 1986-04-02T13:00:00 1989 application/zip, 6 datasets https://doi.pangaea.de/10.1594/PANGAEA.746239 https://doi.org/10.1594/PANGAEA.746239 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.746239 https://doi.org/10.1594/PANGAEA.746239 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess Supplement to: Ruddiman, William F; Janecek, Thomas R (1989): Pliocene-Pleistocene biogenic and terrigenous fluxes at equatorial Atlantic Sites 662, 663, and 664. In: Ruddiman, W; Sarnthein, M; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 108, 211-240, https://doi.org/10.2973/odp.proc.sr.108.165.1989 108-662A 108-663A 108-664B 108-664D DRILL Drilling/drill rig Joides Resolution Leg108 North Atlantic Ocean Ocean Drilling Program ODP South Atlantic Ocean dataset publication series 1989 ftpangaea https://doi.org/10.1594/PANGAEA.74623910.2973/odp.proc.sr.108.165.1989 2024-08-21T00:02:25Z High-resolution analyses of sediments at equatorial Atlantic Sites 662, 663, and 664 define the accumulation rates of biogenically produced CaC03 and opal and of eolian dust from North Africa over the last 3.7 m.y. The mean flux of opal increased abruptly by 60%-70% near 2.5 Ma (2.65 to 2.3 Ma), reflecting pulses of increased opal productivity along the equator due mainly to increased upwelling. The mean winter-plume dust influx from Sahelian and Saharan Africa also increased at this time by between 35% and 75%, following smaller increases earlier in the late Pliocene. The increased opal flux implies a stronger zonal component of the southern trade winds in Southern Hemisphere winter. Consistent with this wind configuration, the stronger dust flux suggests a weaker southwesterly monsoonal flow into Africa in Northern Hemisphere summer, thus increasing Sahelian aridity and winter-plume dust fluxes. Dust fluxes to the equator may possibly have also been enhanced by stronger Northern Hemisphere winter trade winds and a more southerly position of the Intertropical Convergence Zone over Africa. These late Pliocene biogenic and terrigenous flux changes coincided with the appearance of Northern Hemisphere ice sheets, implying an ultimate causal link. The immediate control on changes in tropical circulation may, however, have been changes in the Atlantic sector of the Southern Ocean. A steady background trend of increasing winter-plume dust flux occurred from the late Pliocene until the middle Pleistocene. This may reflect a progressive, tectonically induced aridification of northern and eastern Africa because of the gradual uplift of the Tibetan Plateau. Other/Unknown Material North Atlantic South Atlantic Ocean Southern Ocean PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-23.227500,-11.739200,0.107300,-1.390200) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
108-662A 108-663A 108-664B 108-664D DRILL Drilling/drill rig Joides Resolution Leg108 North Atlantic Ocean Ocean Drilling Program ODP South Atlantic Ocean |
spellingShingle |
108-662A 108-663A 108-664B 108-664D DRILL Drilling/drill rig Joides Resolution Leg108 North Atlantic Ocean Ocean Drilling Program ODP South Atlantic Ocean Ruddiman, William F Janecek, Thomas R Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
topic_facet |
108-662A 108-663A 108-664B 108-664D DRILL Drilling/drill rig Joides Resolution Leg108 North Atlantic Ocean Ocean Drilling Program ODP South Atlantic Ocean |
description |
High-resolution analyses of sediments at equatorial Atlantic Sites 662, 663, and 664 define the accumulation rates of biogenically produced CaC03 and opal and of eolian dust from North Africa over the last 3.7 m.y. The mean flux of opal increased abruptly by 60%-70% near 2.5 Ma (2.65 to 2.3 Ma), reflecting pulses of increased opal productivity along the equator due mainly to increased upwelling. The mean winter-plume dust influx from Sahelian and Saharan Africa also increased at this time by between 35% and 75%, following smaller increases earlier in the late Pliocene. The increased opal flux implies a stronger zonal component of the southern trade winds in Southern Hemisphere winter. Consistent with this wind configuration, the stronger dust flux suggests a weaker southwesterly monsoonal flow into Africa in Northern Hemisphere summer, thus increasing Sahelian aridity and winter-plume dust fluxes. Dust fluxes to the equator may possibly have also been enhanced by stronger Northern Hemisphere winter trade winds and a more southerly position of the Intertropical Convergence Zone over Africa. These late Pliocene biogenic and terrigenous flux changes coincided with the appearance of Northern Hemisphere ice sheets, implying an ultimate causal link. The immediate control on changes in tropical circulation may, however, have been changes in the Atlantic sector of the Southern Ocean. A steady background trend of increasing winter-plume dust flux occurred from the late Pliocene until the middle Pleistocene. This may reflect a progressive, tectonically induced aridification of northern and eastern Africa because of the gradual uplift of the Tibetan Plateau. |
format |
Other/Unknown Material |
author |
Ruddiman, William F Janecek, Thomas R |
author_facet |
Ruddiman, William F Janecek, Thomas R |
author_sort |
Ruddiman, William F |
title |
Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
title_short |
Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
title_full |
Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
title_fullStr |
Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
title_full_unstemmed |
Biogenic and terrigeneous components in Pliocene-Pleistocene sediments of the equatorial Atlantic |
title_sort |
biogenic and terrigeneous components in pliocene-pleistocene sediments of the equatorial atlantic |
publisher |
PANGAEA |
publishDate |
1989 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.746239 https://doi.org/10.1594/PANGAEA.746239 |
op_coverage |
MEDIAN LATITUDE: -0.693789 * MEDIAN LONGITUDE: -16.636249 * SOUTH-BOUND LATITUDE: -1.390200 * WEST-BOUND LONGITUDE: -23.227500 * NORTH-BOUND LATITUDE: 0.107300 * EAST-BOUND LONGITUDE: -11.739200 * DATE/TIME START: 1986-03-24T03:00:00 * DATE/TIME END: 1986-04-02T13:00:00 |
long_lat |
ENVELOPE(-23.227500,-11.739200,0.107300,-1.390200) |
genre |
North Atlantic South Atlantic Ocean Southern Ocean |
genre_facet |
North Atlantic South Atlantic Ocean Southern Ocean |
op_source |
Supplement to: Ruddiman, William F; Janecek, Thomas R (1989): Pliocene-Pleistocene biogenic and terrigenous fluxes at equatorial Atlantic Sites 662, 663, and 664. In: Ruddiman, W; Sarnthein, M; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 108, 211-240, https://doi.org/10.2973/odp.proc.sr.108.165.1989 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.746239 https://doi.org/10.1594/PANGAEA.746239 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1594/PANGAEA.74623910.2973/odp.proc.sr.108.165.1989 |
_version_ |
1810464494877409280 |