Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean
Quantitative analyses of selected calcareous nannofossils in deep-sea sections recovered from the paleo-equatorial Pacific (ODP Leg 199) provide new information about biostratigraphy, biochronology and the evolutionary history of calcareous nannofossils across the Paleocene/Eocene transition interva...
Published in: | Palaeogeography, Palaeoclimatology, Palaeoecology |
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Online Access: | https://eprints.soton.ac.uk/17464/ https://eprints.soton.ac.uk/17464/1/RaffiBackmanPalike_PPP2005.pdf |
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ftsouthampton:oai:eprints.soton.ac.uk:17464 2023-07-30T04:05:35+02:00 Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean Raffi, I. Backman, J. Pälike, H. 2005 text https://eprints.soton.ac.uk/17464/ https://eprints.soton.ac.uk/17464/1/RaffiBackmanPalike_PPP2005.pdf en eng https://eprints.soton.ac.uk/17464/1/RaffiBackmanPalike_PPP2005.pdf Raffi, I., Backman, J. and Pälike, H. (2005) Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology, 226 (1–2), 93-126. (doi:10.1016/j.palaeo.2005.05.006 <http://dx.doi.org/10.1016/j.palaeo.2005.05.006>). Article PeerReviewed 2005 ftsouthampton https://doi.org/10.1016/j.palaeo.2005.05.006 2023-07-09T20:34:21Z Quantitative analyses of selected calcareous nannofossils in deep-sea sections recovered from the paleo-equatorial Pacific (ODP Leg 199) provide new information about biostratigraphy, biochronology and the evolutionary history of calcareous nannofossils across the Paleocene/Eocene transition interval. The sediment cores from ODP Leg 199 represent the first continuous Paleocene/Eocene boundary sections ever to be sampled in the central equatorial Pacific Ocean. Calcareous nannofossil assemblages are studied to document the distribution of biostratigraphically useful taxa such as Ericsonia, Discoaster, Fasciculithus, Rhomboaster and Tribrachiatus. Focus is given to the evolution of the Rhomboaster–Tribrachiatus lineage in the lower Eocene interval at Site 1215, and on the stratigraphic relationship of these taxa relative to species in the genus Fasciculithus. Critical intervals of North Atlantic DSDP Site 550 have also been re-examined. The Tribrachiatus digitalis morphotype was described at Site 550 from an interval affected by down-hole contamination, partly originating from within the Tribrachiatus orthostylus range. The T. digitalis morphotype represents an evolutionary transitional form between T. contortus and T. orthostylus, entering the stratigraphic record within the range of the former species and disappearing within the lower part of the range of the latter species. The subzonal subdivision of Zone NP10 hence collapses. Lithological and colour variability reflecting orbital cyclicity occur in the lower Eocene of Site 1215, permitting a relative astronomical age calibration of the Tribrachiatus taxa. The distinct Rhomboaster spp.–Discoaster araneus association also occurs in the paleo-equatorial Pacific Ocean, together with a marked decrease in diversity of Fasciculithus spp. Site 1220 reveals a short peak abundance of Thoracosphaera spp. just above the P/E boundary interval, which probably reflects a stressed surface water environment. Article in Journal/Newspaper North Atlantic University of Southampton: e-Prints Soton Pacific Palaeogeography, Palaeoclimatology, Palaeoecology 226 1-2 93 126 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Quantitative analyses of selected calcareous nannofossils in deep-sea sections recovered from the paleo-equatorial Pacific (ODP Leg 199) provide new information about biostratigraphy, biochronology and the evolutionary history of calcareous nannofossils across the Paleocene/Eocene transition interval. The sediment cores from ODP Leg 199 represent the first continuous Paleocene/Eocene boundary sections ever to be sampled in the central equatorial Pacific Ocean. Calcareous nannofossil assemblages are studied to document the distribution of biostratigraphically useful taxa such as Ericsonia, Discoaster, Fasciculithus, Rhomboaster and Tribrachiatus. Focus is given to the evolution of the Rhomboaster–Tribrachiatus lineage in the lower Eocene interval at Site 1215, and on the stratigraphic relationship of these taxa relative to species in the genus Fasciculithus. Critical intervals of North Atlantic DSDP Site 550 have also been re-examined. The Tribrachiatus digitalis morphotype was described at Site 550 from an interval affected by down-hole contamination, partly originating from within the Tribrachiatus orthostylus range. The T. digitalis morphotype represents an evolutionary transitional form between T. contortus and T. orthostylus, entering the stratigraphic record within the range of the former species and disappearing within the lower part of the range of the latter species. The subzonal subdivision of Zone NP10 hence collapses. Lithological and colour variability reflecting orbital cyclicity occur in the lower Eocene of Site 1215, permitting a relative astronomical age calibration of the Tribrachiatus taxa. The distinct Rhomboaster spp.–Discoaster araneus association also occurs in the paleo-equatorial Pacific Ocean, together with a marked decrease in diversity of Fasciculithus spp. Site 1220 reveals a short peak abundance of Thoracosphaera spp. just above the P/E boundary interval, which probably reflects a stressed surface water environment. |
format |
Article in Journal/Newspaper |
author |
Raffi, I. Backman, J. Pälike, H. |
spellingShingle |
Raffi, I. Backman, J. Pälike, H. Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
author_facet |
Raffi, I. Backman, J. Pälike, H. |
author_sort |
Raffi, I. |
title |
Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
title_short |
Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
title_full |
Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
title_fullStr |
Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
title_full_unstemmed |
Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean |
title_sort |
changes in calcareous nannofossil assemblages across the paleocene/eocene transition from the paleo-equatorial pacific ocean |
publishDate |
2005 |
url |
https://eprints.soton.ac.uk/17464/ https://eprints.soton.ac.uk/17464/1/RaffiBackmanPalike_PPP2005.pdf |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://eprints.soton.ac.uk/17464/1/RaffiBackmanPalike_PPP2005.pdf Raffi, I., Backman, J. and Pälike, H. (2005) Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology, 226 (1–2), 93-126. (doi:10.1016/j.palaeo.2005.05.006 <http://dx.doi.org/10.1016/j.palaeo.2005.05.006>). |
op_doi |
https://doi.org/10.1016/j.palaeo.2005.05.006 |
container_title |
Palaeogeography, Palaeoclimatology, Palaeoecology |
container_volume |
226 |
container_issue |
1-2 |
container_start_page |
93 |
op_container_end_page |
126 |
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1772817586135760896 |