Changes in calcareous nannofossil assemblages across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean

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doi: 10.1016/j.palaeo.2005.05.006
Author(s): Raffi, Isabella; Backman, Jan; Palike, Heiko
Author Affiliation(s): Primary:
Universita "G. d'Annunzio", Dipartimento di Scienze della Terra, Chieti Scalo, Italy
Stockholm University, Sweden
Southampton Oceanography Centre, United Kingdom
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, 226(1-2), p.93-126. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 74 refs.; illus., incl. 4 plates, 7 tables, sketch maps
Summary: 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. Abstract Copyright (2005) Elsevier, B.V.
Year of Publication: 2005
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Assemblages; Biochronology; Biostratigraphy; Biozones; Calibration; Cenozoic; Cores; Correlation; Cyclostratigraphy; DSDP Site 550; Deep Sea Drilling Project; Eocene; Equatorial Pacific; IPOD; Leg 199; Leg 80; Lower Eocene; Marine sediments; Microfossils; Nannofossils; North Pacific; ODP Site 1215; ODP Site 1220; ODP Site 1221; Ocean Drilling Program; Pacific Ocean; Paleo-oceanography; Paleocene; Paleocene-Eocene boundary; Paleogene; Plantae; Sediments; Stratigraphic boundary; Tertiary; Upper Paleocene
Coordinates: N101100 N101100 W1424500 W1424600
N120200 N120200 W1434200 W1434200
N260200 N260200 W1475600 W1475600
N483054 N483055 W0132622 W0132623
Record ID: 2005076226
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands