Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic
50 m of Middle Eocene pure radiolarian ooze were drilled at ODP Site 660 in the equatorial East Atlantic, 80 km northeast of the Kane Gap. The oozes comprise a 10 m high and 2 km broad mound of seismic reverberations, covered by manganese-rich sediment, and contain trace amounts of sponge spicules a...
Published in: | Sedimentary Geology |
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1993
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Online Access: | https://oceanrep.geomar.de/id/eprint/33624/ https://oceanrep.geomar.de/id/eprint/33624/1/Sarnthein.pdf https://doi.org/10.1016/0037-0738(93)90118-O |
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ftoceanrep:oai:oceanrep.geomar.de:33624 2023-05-15T14:04:43+02:00 Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic Sarntheim, Michael Faugères, J.C. 1993 text https://oceanrep.geomar.de/id/eprint/33624/ https://oceanrep.geomar.de/id/eprint/33624/1/Sarnthein.pdf https://doi.org/10.1016/0037-0738(93)90118-O en eng Elsevier https://oceanrep.geomar.de/id/eprint/33624/1/Sarnthein.pdf Sarntheim, M. and Faugères, J. C. (1993) Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic. Sedimentary Geology, 82 (1-4). pp. 145-155. DOI 10.1016/0037-0738(93)90118-O <https://doi.org/10.1016/0037-0738%2893%2990118-O>. doi:10.1016/0037-0738(93)90118-O info:eu-repo/semantics/restrictedAccess Article PeerReviewed 1993 ftoceanrep https://doi.org/10.1016/0037-0738(93)90118-O 2023-04-07T15:27:11Z 50 m of Middle Eocene pure radiolarian ooze were drilled at ODP Site 660 in the equatorial East Atlantic, 80 km northeast of the Kane Gap. The oozes comprise a 10 m high and 2 km broad mound of seismic reverberations, covered by manganese-rich sediment, and contain trace amounts of sponge spicules and diatoms, negligible organic carbon (0.15%), clay, and variable amounts of pyrite. The yellow to pale brown silty sediments are relatively coarse-grained (30–45% coarser than 6 μm), little bioturbated, and commonly massive or laminated on a cm-scale. The unlithified radiolarian ooze may indicate an interval of high oceanic productivity, probably linked to a palaeoposition of Site 660 close to the equatorial upwelling belt during Middle Eocene time. The absence of organic matter, however, and both the laminated bedding and the mound-like structure of the deposit on the lower slope of a continental rise indicate deposition by relatively intense contour currents of oxygen-rich deep water, which passed through the Kane Gap, winnowed the fine clay fraction, and prevented the preservation of organic carbon. The ooze may be either a contourite-lag deposit, or a contourite accumulation of displaced radiolarians, originating south of the Kane Gap and being deposited in its northern lee, thus documenting the passage of a strong cross-equatorial bottom-water current formed near Antarctica. These Eocene contourites may be an analogue for ancient radiolarites in the Tethyan Ocean. Article in Journal/Newspaper Antarc* Antarctica OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Kane ENVELOPE(-63.038,-63.038,-73.952,-73.952) Sedimentary Geology 82 1-4 145 155 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
50 m of Middle Eocene pure radiolarian ooze were drilled at ODP Site 660 in the equatorial East Atlantic, 80 km northeast of the Kane Gap. The oozes comprise a 10 m high and 2 km broad mound of seismic reverberations, covered by manganese-rich sediment, and contain trace amounts of sponge spicules and diatoms, negligible organic carbon (0.15%), clay, and variable amounts of pyrite. The yellow to pale brown silty sediments are relatively coarse-grained (30–45% coarser than 6 μm), little bioturbated, and commonly massive or laminated on a cm-scale. The unlithified radiolarian ooze may indicate an interval of high oceanic productivity, probably linked to a palaeoposition of Site 660 close to the equatorial upwelling belt during Middle Eocene time. The absence of organic matter, however, and both the laminated bedding and the mound-like structure of the deposit on the lower slope of a continental rise indicate deposition by relatively intense contour currents of oxygen-rich deep water, which passed through the Kane Gap, winnowed the fine clay fraction, and prevented the preservation of organic carbon. The ooze may be either a contourite-lag deposit, or a contourite accumulation of displaced radiolarians, originating south of the Kane Gap and being deposited in its northern lee, thus documenting the passage of a strong cross-equatorial bottom-water current formed near Antarctica. These Eocene contourites may be an analogue for ancient radiolarites in the Tethyan Ocean. |
format |
Article in Journal/Newspaper |
author |
Sarntheim, Michael Faugères, J.C. |
spellingShingle |
Sarntheim, Michael Faugères, J.C. Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
author_facet |
Sarntheim, Michael Faugères, J.C. |
author_sort |
Sarntheim, Michael |
title |
Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
title_short |
Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
title_full |
Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
title_fullStr |
Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
title_full_unstemmed |
Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic |
title_sort |
radiolarian contourites record eocene aabw circulation in the equatorial east atlantic |
publisher |
Elsevier |
publishDate |
1993 |
url |
https://oceanrep.geomar.de/id/eprint/33624/ https://oceanrep.geomar.de/id/eprint/33624/1/Sarnthein.pdf https://doi.org/10.1016/0037-0738(93)90118-O |
long_lat |
ENVELOPE(-63.038,-63.038,-73.952,-73.952) |
geographic |
Kane |
geographic_facet |
Kane |
genre |
Antarc* Antarctica |
genre_facet |
Antarc* Antarctica |
op_relation |
https://oceanrep.geomar.de/id/eprint/33624/1/Sarnthein.pdf Sarntheim, M. and Faugères, J. C. (1993) Radiolarian contourites record Eocene AABW circulation in the equatorial East Atlantic. Sedimentary Geology, 82 (1-4). pp. 145-155. DOI 10.1016/0037-0738(93)90118-O <https://doi.org/10.1016/0037-0738%2893%2990118-O>. doi:10.1016/0037-0738(93)90118-O |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/0037-0738(93)90118-O |
container_title |
Sedimentary Geology |
container_volume |
82 |
container_issue |
1-4 |
container_start_page |
145 |
op_container_end_page |
155 |
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1766275963919794176 |