Affordable Access

Publisher Website

Middle Eocene to early Oligocene planktonic and benthic foraminifers from ODP Hole 125-786A

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.729527
Keywords
  • ?Pseudoolina Sp
  • Cf
  • P
  • Bouei
  • 125-786A
  • A
  • Bullbrooki
  • Acarinina Bullbrooki
  • Anomalinoides Sp
  • Astacolus Sp
  • B
  • Alazanensis
  • B
  • Glomarchallengeri
  • B
  • Grata
  • B
  • Grata Spinosa
  • B
  • Jarvisi
  • Bulimina Alazanensis
  • Bulimina Glomarchallengeri
  • Bulimina Jarvisi
  • Bulimina Sp
  • Buliminella Grata
  • Buliminella Grata Spinosa
  • C
  • Dissimilis
  • C
  • Eocaenus
  • C
  • Havanensis
  • C
  • Inflata
  • C
  • Praemundulus
  • Cassidulina Havanensis
  • Catapsydrax Dissimilis
  • Cf
  • Barri
  • Chrysalogonium Sp
  • Cibicidoides Eocaenus
  • Cibicidoides Praemundulus
  • Cribrohantkenina Inflata
  • Drilling
  • Ellipsodimorphina Sp
  • Ellipsoglandulina Sp
  • Ellipsoidina Sp
  • Foram Bent Preserv
  • Foraminifera
  • Benthic Preservation
  • Foraminifera
  • Planktic Preservation
  • Foram Plankt Preserv
  • G
  • Carcoselleensis
  • G
  • Corpulenta
  • G
  • Girardana
  • G
  • Mexicana
  • G
  • Mexicana Mexicana
  • G
  • Praeturritilina
  • G
  • Problema
  • G
  • Subglobosa
  • G
  • Tripartita
  • G = Good
  • M = Moderate
  • P = Poor
  • Globigerina Corpulenta
  • Globigerina Praeturritilina
  • Globigerina Sp
  • Globigerinatheka Mexicana
  • Globigerinatheka Mexicana Mexicana
  • Globigerina Tripartita
  • Globobulimina Sp
  • Globocassidulina Subglobosa
  • Globorotaloides Carcoselleensis
  • Guttulina Problema
  • Gyroidinoides Girardana
  • Gyroidinoides Sp
  • H
  • Alabamensis
  • Hantkenina Alabamensis
  • Joides Resolution
  • K
  • Subglabra
  • Karreriella Subglabra
  • Label
  • Laevidentalina Sp
  • Leg125
  • Lenticulina Sp
  • M
  • Aragonensis
  • M
  • Spinulosa
  • Morozovella Aragonensis
  • Morozovella Spinulosa
  • N
  • Truempyi
  • Nodogenerina Sp
  • Nodosarella Sp
  • North Pacific Ocean
  • Number Of Species
  • Nuttallides Truempyi
  • O
  • Mexicana
  • O
  • Umbonatus
  • Ocean Drilling Program
  • Odp
  • Odp Sample Designation
  • Oolina Sp
  • Oridorsalis Umbonatus
  • Osangularia Mexicana
  • P
  • Acuta
  • P
  • Bierigi
  • P
  • Bulloides
  • P
  • Crassicarinata
  • P
  • Incrassata
  • P
  • Micra
  • P
  • Naguewichiensis
  • P
  • Paucicostata
  • P
  • Quinqueloba
  • Palliolatella Sp
  • Plectofrondicularia Paucicostata
  • Pleurostomella Acuta
  • Pleurostomella Bierigi
  • Pleurostomella Incrassata
  • Pleurostomella Sp
  • Protoglobobulimina Sp
  • Pseudofissurina Crassicarinata
  • Pseudohastigerina Micra
  • Pseudohastigerina Naguewichiensis
  • Pseudonodosaria Sp
  • Pseudoolina Sp
  • Pullenia Bulloides
  • Pullenia Quinqueloba
  • Pygmaeoseistron Sp
  • Pyramidulina Sp
  • Q
  • Pyramidalis
  • Quadratobuliminella Pyramidalis
  • Questionable
  • S
  • Cf
  • Aculeata
  • S
  • Eocaena
  • S
  • Euapertura
  • S
  • Linaperta
  • S
  • Subspinosa
  • Sample Code/Label
  • Siphonodosaria Cf
  • Aculeata
  • Siphonodosaria Sp
  • Sp
  • A
  • Spec No
  • Spiroplectammina Sp
  • Stilostomella Sp
  • Stilostomella Subspinosa
  • Subbotina Eocaena
  • Subbotina Euapertura
  • Subbotina Linaperta
  • T
  • Cerroaz
  • Cocoaensis
  • T
  • Cerroaz
  • Pomeroli
  • Turborotalia Cerroazulensis Cocoaensis
  • Turborotalia Cerroazulensis Pomeroli
  • V
  • Spinosa
  • Vulvulina Spinosa
Disciplines
  • Earth Science

Abstract

Drilling at Site 786, located in the center of the Izu-Bonin forearc basin, penetrated an apparently continuous section of middle Eocene/lower Oligocene volcaniclastic breccias and nannofossil oozes. Planktonic foraminiferal faunas underwent a gradual transition from relatively high-diversity middle Eocene through late Eocene tropical or warm-water assemblages to a cooler-water, less diverse assemblage during the early Oligocene. In the cosmopolitan benthic foraminiferal faunas, the major transition occurred during the early late Eocene. Middle Eocene benthic assemblages resembling the bathyal 'Lenticulina' fauna (characterized by Osangularia mexicana, Cibicidoides eocaenus, and several buliminid species) changed to an upper Eocene abyssal 'Globocassidulina subglobosa' fauna (characterized by Cibicidoides praemundulus, Globocassidulina subglobosa, Gyroidinoides girardanus, Oridorsalis umbonatus, and Siphonodosaria aculeata). Even though no large, abrupt faunal changes appear to have been associated with the assumed Eocene/Oligocene boundary, benthic species turnover continued through the late Eocene and into the early Oligocene. This resulted in a slightly lower diversity early Oligocene fauna dominated by three species: Laevidentalina sp., Bulimina jarvisi, and Gyroidinoides girardanus. The progression from a middle Eocene bathyal 'Lenticulina' fauna, rather than an abyssal 'Nuttallides truempyi' fauna, to an abyssal 'Globocassidulina subglobosa' fauna during the early late Eocene, suggests that a bathymetric deepening occurred at Site 786. Increased water depths may have resulted from tectonic subsidence.

There are no comments yet on this publication. Be the first to share your thoughts.