The biostratigraphy and paleobiology of Oligocene planktonic foraminifera from the equatorial Pacific Ocean (ODP Site 1218)

Planktonic foraminifera from a continuous Oligocene succession with clear magnetochronology and sediment cycles at Ocean Drilling Program Site 1218 (equatorial Pacific Ocean) were studied in the interval from 27 to 30 Ma. Paragloborotalia taxa are common and we examined their size, relative abundance, and stable isotopes. Multispecies stable isotope data indicate the depth habitats of Oligocene planktonic foraminifera and suggest that “Globoquadrina” venezuelana and Dentoglobigerina globularis were probably mixed-layer dwellers, with paragloborotaliids recording heavier δ 18 O signatures consistent with a thermocline habitat. Cyclic variations in the abundance of Paragloborotalia match eccentricity (100 kyr) variations in percent carbonate and δ 13 C, suggesting orbitally forced upwelling in the equatorial Pacific Ocean and that Paragloborotalia were responding directly to changes in surface water productivity. The high-resolution biostratigraphy calibrated to the magnetochronology constrains the extinction of Paragloborotalia opima which marks the top of Planktonic Foraminifera Biozone O5 (P21b) at 27.456 Ma. The highest occurrence of P. opima is associated with a 50% size decrease in Paragloborotalia pseudocontinuosa taxa within Chron 9n. In addition, we find the extinction of Chiloguembelina cubensis is consistent with other deep-sea sections within Chron 10n at 28.426 Ma marking the O4/O5 (P21a/P21b) boundary.

[1]  R. Douglas.  Planktonic Foraminiferal Biostratigraphy in the Central North Pacific Ocean , 1973 .

[2]  Christopher J. Nicholas,et al.  Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs , 2001, Nature.

[3]  B. Huber.  Paleogene and Early Neogene Planktonic Foraminifer Biostratigraphy of Sites 738 and 744, Kerguelen Plateau (Southern Indian Ocean) , 1991 .

[4]  R. Huene,et al.  Initial reports of the deep sea drilling project: National Science Foundation, Washington, D.C., 1969, 672 pp., U.S. $ 10.25 , 1971 .

[5]  B. Wade.  Planktonic foraminiferal biostratigraphy and mechanisms in the extinction of Morozovella in the late middle Eocene , 2004 .

[6]  K. Miller,et al.  MAGNETOSTRATIGRAPHY OF OLIGOCENE TO PLEISTOCENE SEDIMENTS , SITES 558 AND 563 1 , 2006 .

[7]  R. Poore,et al.  Late EoceneOligocene Oxygen and CarbonIsotope Record from South Atlantic Ocean, Deep Sea Drilling Project Site 522 , 1984 .

[8]  C. Pujol.  Cenozoic Planktonic Foraminiferal Biostratigraphy of the Southwestern Atlantic (Rio Grande Rise): Deep Sea Drilling Project Leg 72 , 1983 .

[9]  H. Pälike,et al.  Data report: Oligocene paleoceanography of the equatorial Pacific ocean: Planktonic and benthic foraminifer stable isotope results from site 1218 , 2004 .

[10]  Nicholas J Shackleton,et al.  Oxygen Isotope and Palaeomagnetic Stratigraphy of Equatorial Pacific Core V28-238: Oxygen Isotope Temperatures and Ice Volumes on a 105 Year and 106 Year Scale , 1973, Quaternary Research.

[11]  Luca Lanci,et al.  Oligocene magnetostratigraphy from Equatorial Pacific sediments (ODP Sites 1218 and 1219, Leg 199) , 2005 .

[12]  R. Poore,et al.  Late Eocene–Oligocene magnetostratigraphy and biostratigraphy at South Atlantic DSDP Site 522 , 1982 .

[13]  D. Echols.  Lower Oligocene through Pleistocene Planktonic Foraminiferal Biostratigraphy, North Atlantic Sites 558 and 563 (Mid-Atlantic Ridge) , 1985 .

[14]  M. Biolzi.  Stable isotopic study of Oligocene-Miocene sediments from DSDP Site 354, Equatorial Atlantic , 1983 .

[15]  W. Berggren,et al.  Paleogene tropical planktonic foraminiferal biostratigraphy and magnetobiochronology , 1988 .

[16]  S. Cande,et al.  Revised calibration of the geomagnetic polarity timescale for the Late Cretaceous and Cenozoic , 1995 .

[17]  A. Klaus,et al.  Proceedings of the Ocean Drilling Program, Scientific Results , 2001 .

[18]  M. Bender,et al.  The Oligocene marine microfossil record: Age assessments using strontium isotopes: Paleoceanography , 1989 .

[19]  J. Kennett,et al.  Vertical thermal structure evolution of Miocene surface waters: Western equatorial Pacific DSDP Site 289 , 1993 .

[20]  S. Savin,et al.  Oxygen isotopic evidence for the depth stratification of tertiary and cretaceous planktic foraminifera , 1978 .

[21]  G. Ganssen,et al.  An Oligocene multi-species foraminiferal oxygen and carbon isotope record from ODP Hole 758A (Indian Ocean): paleoceanographic and paleo-ecologic implications , 1995 .

[22]  R. Leckie,et al.  Oligocene Planktonic Foraminifer Biostratigraphy of Hole 803D (Ontong Java Plateau) and Hole 628A (Little Bahama Bank), and Comparison with the Southern High Latitudes , 1993 .

[23]  W. Lowrie,et al.  Paleogene magnetic stratigraphy in Umbrian pelagic carbonate rocks: The Contessa sections, Gubbio , 1982 .

[24]  R. Poore,et al.  Late cretaceous—cenozoic magnetostratigraphic and biostratigraphic correlations of the South Atlantic Ocean: DSDP Leg 73 , 1983 .

[25]  D. Schrag.  Effects of diagenesis on the isotopic record of late paleogene tropical sea surface temperatures , 1999 .

[26]  H. Pälike,et al.  Oligocene climate dynamics , 2004 .

[27]  P. Pearson,et al.  A revised tropical to subtropical Paleogene planktonic foraminiferal zonation , 2005 .

[28]  H. Brinkhuis,et al.  Stratigraphic and palaeoenvironmental analysis of the Rupelian–Chattian transition in the type region: evidence from dinoflagellate cysts, foraminifera and calcareous nannofossils , 2004 .

[29]  I. P. Silva,et al.  Oligocene planktonic foraminiferal biostratigraphy and paleoclimatic interpretation from Hole 538A, DSDP Leg 77, Gulf of Mexico , 1991 .

[30]  Marie-Pierre Aubry,et al.  A revised Cenozoic geochronology and chronostratigraphy , 1995 .

[31]  W. Berggren,et al.  Oligocene-Miocene biostratigraphy, magnetostratigraphy, and isotopic stratigraphy of the western North Atlantic , 1985 .

[32]  J. LaBrecque,et al.  The magnetostratigraphy of Leg 73 sediments , 1983 .

[33]  J. Kennett,et al.  A FORAMINIFERAL ISOTOPIC PROXY FOR UPPER WATER MASS STRATIFICATION , 2002 .

[34]  Christoph Hemleben,et al.  Modern Planktonic Foraminifera , 1988, Springer New York.

[35]  D. Kroon,et al.  Upwelling in the late middle Eocene at Blake Nose? , 2000 .

[36]  N. Shackleton,et al.  36. OXYGEN AND CARBON ISOTOPE RECORD THROUGH THE OLIGOCENE, DSDP SITE 366, EQUATORIAL ATLANTIC , 2006 .

[37]  T. R. Janecek,et al.  Integrated stratigraphic correlation and improved composite depth scales for ODP Sites 1218 and 1219 , 2006 .