TY - JOUR
T1 - Global changes of Paleogene aerobic/anaerobic benthic foraminifera and deep-sea circulation
AU - Kaiho, Kunio
N1 - Funding Information:
I would like to thank the Ocean Drilling Program and H. E. G. Morgans (New Zealand Geological Survey) for providing samples used in this study except for those from the Tawanui section. I wish to acknowledge the advice of J. C. Ingle Jr., T. Kikuchi, and N. Handa on some pertinent literature. I am thankful to M. Okamura for his assistance with bioturbation analysis and to S. Otomo for his photographic assistance. l am very grateful to A. Boersma, R. C. Tjalsma. I. Premoli Silva, E. M/.iller-Mertz, and K. lshizaki for critically reviewing the manuscript and useful comments and to Y. Takayanagi and T. Saito for their advice on some figures and the draft. Part of this research was supported by the Ministry of Education, Science and Culture, the Government of Japan, under a Grant-in-Aid for Overseas Scientific Survey, Grant 60041004.
PY - 1991/2
Y1 - 1991/2
N2 - Morphologies of calcareous benthic foraminifera found in poorly oxygenated deposits differ from those present in highly oxygenated deposits. On the basis of this observation, I infer that benthicfforaminiferal test morphology can be used to extrapolate relative amounts of dissolved oxygen in Paleogene deep-sea bottom water. Calcareous benthic foraminifera from DSDP samples of Cenozoic age from the world oceans and New Zealand Paleogene samples are classified into three categories: aerobic, anaerobic and intermediate forms. The ratio of aerobic versus aerobic plus anaerobic forms is useful for estimates of global changes in the oxygen content of deep oceanic waters. These data indicate that low oxygen deep-sea conditions developed in the world oceans in early Eocene and late Oligocene times. These low-oxygen events occurred coincidentally with episodes of oceanic warming and sluggish deep water circulation. This coincidence suggests that the main cause of the low-oxygen events is low velocity deep-sea circulation in those time intervals.
AB - Morphologies of calcareous benthic foraminifera found in poorly oxygenated deposits differ from those present in highly oxygenated deposits. On the basis of this observation, I infer that benthicfforaminiferal test morphology can be used to extrapolate relative amounts of dissolved oxygen in Paleogene deep-sea bottom water. Calcareous benthic foraminifera from DSDP samples of Cenozoic age from the world oceans and New Zealand Paleogene samples are classified into three categories: aerobic, anaerobic and intermediate forms. The ratio of aerobic versus aerobic plus anaerobic forms is useful for estimates of global changes in the oxygen content of deep oceanic waters. These data indicate that low oxygen deep-sea conditions developed in the world oceans in early Eocene and late Oligocene times. These low-oxygen events occurred coincidentally with episodes of oceanic warming and sluggish deep water circulation. This coincidence suggests that the main cause of the low-oxygen events is low velocity deep-sea circulation in those time intervals.
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U2 - 10.1016/0031-0182(91)90076-4
DO - 10.1016/0031-0182(91)90076-4
M3 - Article
AN - SCOPUS:0026021654
SN - 0031-0182
VL - 83
SP - 65
EP - 85
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
IS - 1-3
ER -