TY - JOUR
T1 - Late middle Eocene to late Oligocene radiolarian biostratigraphy in the Southern Ocean (Maud Rise, ODP Leg 113, Site 689)
AU - Funakawa, Satoshi
AU - Nishi, Hiroshi
N1 - Funding Information:
The samples were supplied through the assistance of the U.S. National Science Foundation. We express sincere thanks to Dr. Christopher J. Hollis for criticizing the draft of this paper. We acknowledge Prof. Ellen Thomas and Dr. David Lazarus for critically reviewing the manuscript. This work was financially supported by a Grant-in-Aid for Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists (no. 12000254) to Satoshi Funakawa. A part of the work was carried out at the Micropaleontology Reference Center, Utsunomiya University, Japan.
PY - 2005/3
Y1 - 2005/3
N2 - We propose a new biostratigraphic scheme comprising the Eucyrtidium spinosum, Eucyrtidium antiquum (new), Lychnocanoma conica (emended), Clinorhabdus robusta (emended) and Stylosphaera radiosa (emended) Zones, in ascending order, in Eocene to Oligocene sediments drilled on Maud Rise in Southern Atlantic Ocean (Site 689, Ocean Drilling Program Leg 113). The bases of these zones are defined by the lowermost occurrences of E. spinosum, E. antiquum, L. conica, C. robusta and the uppermost occurrence of Axoprunum irregularis (?), respectively. From correlation to the magnetostratigraphic data, the E. spinosum, E. antiquum, L. conica, C. robusta and S. radiosa Zones are assigned to the late middle Eocene through late Eocene (Subchrons C17n2 to C13r), earliest Oligocene (C13n to C11n), late early Oligocene (C11n to C10n2), early late Oligocene (C10n1 to C8r) and latest Oligocene (C8r to C7An), respectively. The four boundary datum levels and supplementary datum levels such as the lowermost occurrences of A. irregularis (?), Dicolocapsa microcephala and Lithomelissa challengerae may be recognized in other ODP sites in the Southern Ocean. The first occurrence of E. antiquum approximates the Eocene-Oligocene boundary in Southern Ocean but the last occurrences of many species such as Periphaena decora, D. microcephala and the Lithomelissa sphaerocephalis group are commonly diachronous between high latitude sites. Two new species, Theocyrtis (?) triapenna and Spirocyrtis parvaturris, are described.
AB - We propose a new biostratigraphic scheme comprising the Eucyrtidium spinosum, Eucyrtidium antiquum (new), Lychnocanoma conica (emended), Clinorhabdus robusta (emended) and Stylosphaera radiosa (emended) Zones, in ascending order, in Eocene to Oligocene sediments drilled on Maud Rise in Southern Atlantic Ocean (Site 689, Ocean Drilling Program Leg 113). The bases of these zones are defined by the lowermost occurrences of E. spinosum, E. antiquum, L. conica, C. robusta and the uppermost occurrence of Axoprunum irregularis (?), respectively. From correlation to the magnetostratigraphic data, the E. spinosum, E. antiquum, L. conica, C. robusta and S. radiosa Zones are assigned to the late middle Eocene through late Eocene (Subchrons C17n2 to C13r), earliest Oligocene (C13n to C11n), late early Oligocene (C11n to C10n2), early late Oligocene (C10n1 to C8r) and latest Oligocene (C8r to C7An), respectively. The four boundary datum levels and supplementary datum levels such as the lowermost occurrences of A. irregularis (?), Dicolocapsa microcephala and Lithomelissa challengerae may be recognized in other ODP sites in the Southern Ocean. The first occurrence of E. antiquum approximates the Eocene-Oligocene boundary in Southern Ocean but the last occurrences of many species such as Periphaena decora, D. microcephala and the Lithomelissa sphaerocephalis group are commonly diachronous between high latitude sites. Two new species, Theocyrtis (?) triapenna and Spirocyrtis parvaturris, are described.
KW - Eocene to Oligocene
KW - Southern Ocean
KW - biostratigraphy
KW - radiolaria
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U2 - 10.1016/j.marmicro.2004.12.002
DO - 10.1016/j.marmicro.2004.12.002
M3 - Article
AN - SCOPUS:14644430396
VL - 54
SP - 213
EP - 247
JO - Marine Micropaleontology
JF - Marine Micropaleontology
SN - 0377-8398
IS - 3-4
ER -