Upper Cenozoic calcareous nannofossil biostratigraphy and inferred sedimentation, ODP Leg 206, East Pacific Rise

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doi: 10.2973/odp.proc.sr.206.008.2006
Author(s): Jiang, Shijun; Wise, Sherwood W., Jr.
Ocean Drilling Program, Leg 206, Shipboard Scientific Party, College Station, TX
Author Affiliation(s): Primary:
Florida Satet University, Department of Geological Sciences, Tallahassee, FL, United States
Other:
University of California, Santa Barbara, United States
Ocean Drilling Program, United States
University of Michigan, United States
University of Alberta, Canada
University of Leicester, United Kingdom
California Institute of Technology, United States
Universita di Genova, Italy
Université de Montpellier II, France
Florida State University, United States
Bundesanstalt für Geowissenschaften und Rohstoffe, Federal Republic of Germany
University of Utah, United States
Universitë de Aix-Marseille, France
Christian-Albrechts-Universität zu Kiel, Federal Republic of Germany
Macquarie University, Australia
Universita di Milano, Italy
Shizuoka University, Japan
Boston University, United States
Volume Title: Proceedings of the Ocean Drilling Program; volume 206; scientific results; an in situ section of the upper oceanic crust formed by superfast seafloor spreading; covering Leg 206 of the cruises of the drilling vessel JOIDES Resolution; Balboa, Panama to Balboa, Panama; Site 1256; 6 November 2002-4 January 2003
Volume Author(s): Teagle, Damon A. H.; Wilson, Douglas S.; Acton, Gary D.; Alt, Jeffrey C.; Banerjee, Neil R.; Barr, Samantha R.; Coggon, Rosalind; Cooper, Kari M.; Crispini, Laura; Einaudi, Florence; Jiang, Shijun; Kalberkamp, Ulrich; Kerneklian, Marcie J.; Laverne, Christine; Nichols, Holly J.; Sandwell, Rachel; Tartarotti, Paola; Umino, Susumu; Ziegler, Christa
Source: Proceedings of the Ocean Drilling Program; volume 206; scientific results; an in situ section of the upper oceanic crust formed by superfast seafloor spreading; covering Leg 206 of the cruises of the drilling vessel JOIDES Resolution; Balboa, Panama to Balboa, Panama; Site 1256; 6 November 2002-4 January 2003, Damon A. H. Teagle, Douglas S. Wilson, Gary D. Acton, Jeffrey C. Alt, Neil R. Banerjee, Samantha R. Barr, Rosalind Coggon, Kari M. Cooper, Laura Crispini, Florence Einaudi, Shijun Jiang, Ulrich Kalberkamp, Marcie J. Kerneklian, Christine Laverne, Holly J. Nichols, Rachel Sandwell, Paola Tartarotti, Susumu Umino and Christa Ziegler; Ocean Drilling Program, Leg 206, Shipboard Scientific Party, College Station, TX. Proceedings of the Ocean Drilling Program, Scientific Results (CD ROM), Vol.206, 25p. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 1096-2514
Note: In English. Includes appendices. 43 refs.CD-ROM format, ISSN 1096-2514; WWW format, 1096-7451; illus., incl. 2 tables, sketch map
Summary: Site 1256 of Ocean Drilling Program Leg 206 to the Guatemala Basin on the eastern flank of the East Pacific Rise yielded a near-complete, middle Miocene-Quaternary carbonate-rich section that provides an opportunity to study low-latitude biostratigraphic and paleoceanographic events. The sedimentary sequence in Hole 1256B has been zoned using calcareous nannofossils according to the biostratigraphic schemes by Martini of 1971 (modified by Martini and Muller in 1986) and Okada and Bukry of 1980. The nannofossil assemblage is characteristic of the low latitudes, with abundant Gephyrocapsa, Discoaster, and Sphenolithus, and is in general moderately to well preserved, depending on nannofossil abundance and the presence of diatoms. Age estimates for the first occurrence and last occurrence of Reticulofenestra rotaria were derived from biostratigraphy and magnetostratigraphy independently and assigned to 7.18 and 6.32 Ma, respectively. Linear sedimentation rates, calculated using 28 nannofossil datums and age estimates, are high in the middle Miocene, decrease from the late Miocene to the Pliocene, then increase upsection. The abrupt drop in carbonate mass accumulation rates during the early late Miocene is referred to as the "carbonate crash". This pattern reflects (1) the longtrend decrease of productivity as the site moves away from the upwelling system at the equatorial divergence as well as (2) fluctuation in the chemistry of the bottom waters associated with production of the North Atlantic Bottom Water and ventilation via the Panama Gateway. A basement age of 14.5 Ma was obtained by extrapolating the 39.1-m/ m.y. rate in the middle Miocene to the basement at 250.7 meters below seafloor, and is consistent with the ∼15-Ma age of the oceanic crust estimated from marine magnetic anomalies. Reworked nannofossils and lithologic changes were used to unravel postdepositional history, and three episodes were recognized, one of which in the latest Miocene can be widely correlated.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Assemblages; Biostratigraphy; Biozones; Boreholes; Carbonate sediments; Cenozoic; Cores; East Pacific; East Pacific Rise; Equatorial Pacific; Floral list; Guatemala Basin; Leg 206; Marine sedimentation; Marine sediments; Microfossils; Nannofossils; Neogene; North Pacific; Northeast Pacific; ODP Site 1256; Ocean Drilling Program; Pacific Ocean; Paleoenvironment; Plantae; Quaternary; Sedimentation; Sedimentation rates; Sediments; Tertiary; Upper Cenozoic
Coordinates: N064400 N064400 W0915600 W0915600
Record ID: 2007124229
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