Late Eocene to Oligocene preservation history and biochronology of calcareous nannofossils from paleo-equatorial Pacific Ocean sediments

Author(s): Blaj, Teodora; Backman, Jan; Raffi, Isabella
Author Affiliation(s): Primary:
Stockholm University, Department of Geology and Geochemistry, Stockholm, Sweden
Universita Gabriele d'Annunzio di Chieti-Pescara, Italy
Volume Title: Rivista Italiana di Paleontologia e Stratigrafia
Source: Rivista Italiana di Paleontologia e Stratigrafia, 115(1), p.67-85. Publisher: Universita degli Studi di Milano, Istituto di Geologia, Dipartimento di Scienze della Terra, Milan, Italy. ISSN: 0035-6883 CODEN: RPLSAT
Note: In English with Italian summary. Includes appendix. 45 refs.; illus., incl. 2 plates, 2 tables, sketch map
Summary: A continuous late Eocene through Oligocene carbonate sequence was recovered at Ocean Drilling Program (ODP) Site 1218 in the paleo-equatorial Pacific Ocean. The preservation history of selected calcareous nannofossil species across the Eocene/Oligocene (E/O) boundary is presented together with late Eocene and Oligocene calcareous nannofossil biochronology. The astronomically calibrated timescale of Palike et al. (2006) is used here. Across the E/ O boundary, placolith preservation is controlled by variation in carbonate content. Taxa less prone to dissolution are Reticulofenestra umbilicus, Coccolithus pelagicus, Ericsonia formosa and Dictyococites bisectus, while Cydicargolithus floridanus is more susceptible to dissolution. A biochronologic framework has been established for the following taxa: the highest occurrences (HO) of Discoaster barbadiensis (34.773 Ma), D. saipanensis (34.435 Ma), E. formosa (32.919 Ma), R. umbilicus (32.021 Ma), Sphenolithus predistentus (26.928 Ma), S. distentus (26.812 Ma), and S. ciperoensis (24.432 Ma), and the lowest occurrences (LO) of S. distentus (29.997 Ma) and S. ciperoensis (27.142 Ma). The first consistent appearance of Triquetrorhabdulus carinatus occurs at 26.556 Ma, while the onset of the peak interval of T. carinatus was determined at 24.669 Ma. Biochronological comparisons are made with other sites from the Atlantic Ocean. A Triquetrorbabdulus morphotype, labeled as T. aff. carinatus, was recorded for the first time in the studied sediments, and precedes the LO of T. carinatus by ∼0.7 Myr. Its stratigraphic range has a duration of about 3.3 Myr. T. aff. carinatus disappears concomitantly with the beginning of a sharp increase in abundance of T. carinatus.
Year of Publication: 2009
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; Angola Basin; Assemblages; Atlantic Ocean; Biometry; Biostratigraphy; Ceara Rise; Cenozoic; DSDP Site 516; DSDP Site 522; DSDP Site 523; Deep Sea Drilling Project; East Pacific; Eocene; Equatorial Atlantic; Equatorial Pacific; Floral list; IPOD; Leg 108; Leg 154; Leg 199; Leg 72; Leg 73; Microfossils; Nannofossils; North Atlantic; North Pacific; Northeast Pacific; ODP Site 1218; ODP Site 667; ODP Site 925; ODP Site 926; ODP Site 927; ODP Site 928; ODP Site 929; Ocean Drilling Program; Oligocene; Pacific Ocean; Paleogene; Plantae; Preservation; Rio Grande Rise; Sierra Leone Rise; South Atlantic; Tertiary; Upper Eocene
Coordinates: S260651 S260650 W0050646 W0050647
S301636 S301635 W0351706 W0351707
N034308 N092719 W0425429 W0442852
N085300 N085300 W1352200 W1352200
Record ID: 2009060666
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute.