TY - JOUR
T1 - Nannofossil evolutionary events in the mid-Pliocene
T2 - An assessment of the degree of synchrony in the extinctions of Reticulofenestra pseudoumbilicus and Sphenolithus abies
AU - Gibbs, Samantha J.
AU - Young, Jeremy R.
AU - Bralower, Timothy J.
AU - Shackleton, Nicholas J.
N1 - Funding Information:
S.J.G. wishes to thank NERC, Cambridge University, Gonville and Caius College, and the CODENET project (Coccolithophorid Evolutionary Biodiversity and Ecology Network, EC TMR project) for their financial assistance. The Ocean Drilling Program kindly provided samples. Many thanks to Mike Hall and James Rolfe of the Godwin Laboratory for their technical assistance. Thank you also to the CODENET participants, Simon Crowhurst, Michal Kucera, Daniela Schmidt, Brian Huber, and Isabella Raffi, for useful discussion. We are also grateful to Katharina von Salis and Hans Thierstein for their constructive reviews of this manuscript.
PY - 2005/2/11
Y1 - 2005/2/11
N2 - The mid-Pliocene was an interval of subtle reorganisation within the nannoplankton community, including the prominent and biostratigraphically important last occurrences of Sphenolithus abies and Reticulofenestra pseudoumbilicus. The transition is part of the Pliocene to Recent 'attrition' of nannofossil species that resulted from changes in the distribution of trophic resources, and deep-water and surface-water current systems, likely associated with the initiation of Northern Hemisphere glaciation. The extinctions of Sphenolithus abies and Reticulofenestra pseudoumbilicus were analysed in detail at ODP Sites 659, 662, and 926 in the equatorial and subequatorial Atlantic. These taxa show significantly different patterns of duration and timing of decline based on high-resolution abundance records and calibration with oxygen isotope stratigraphy. The initiation of abundance decline between 3.71 and 3.67 Ma and the extinction of S. abies between 3.56 and 3.52 Ma are diachronous. This extinction may have been a response to the intensification of glacial intervals at this time. In contrast, the last occurrence of R. pseudoumbilicus at 3.81-3.82 Ma appears to be a valid example of biostratigraphic (although not necessarily biological) synchrony in the fossil record. Direct environmental forcing is not attributable for the extinction of R. pseudoumbilicus; however, indirect physical and/or biological environmental stress may explain the observed patterns.
AB - The mid-Pliocene was an interval of subtle reorganisation within the nannoplankton community, including the prominent and biostratigraphically important last occurrences of Sphenolithus abies and Reticulofenestra pseudoumbilicus. The transition is part of the Pliocene to Recent 'attrition' of nannofossil species that resulted from changes in the distribution of trophic resources, and deep-water and surface-water current systems, likely associated with the initiation of Northern Hemisphere glaciation. The extinctions of Sphenolithus abies and Reticulofenestra pseudoumbilicus were analysed in detail at ODP Sites 659, 662, and 926 in the equatorial and subequatorial Atlantic. These taxa show significantly different patterns of duration and timing of decline based on high-resolution abundance records and calibration with oxygen isotope stratigraphy. The initiation of abundance decline between 3.71 and 3.67 Ma and the extinction of S. abies between 3.56 and 3.52 Ma are diachronous. This extinction may have been a response to the intensification of glacial intervals at this time. In contrast, the last occurrence of R. pseudoumbilicus at 3.81-3.82 Ma appears to be a valid example of biostratigraphic (although not necessarily biological) synchrony in the fossil record. Direct environmental forcing is not attributable for the extinction of R. pseudoumbilicus; however, indirect physical and/or biological environmental stress may explain the observed patterns.
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U2 - 10.1016/j.palaeo.2004.11.005
DO - 10.1016/j.palaeo.2004.11.005
M3 - Article
AN - SCOPUS:12944287811
SN - 0031-0182
VL - 217
SP - 155
EP - 172
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
IS - 1-2
ER -