A Factorial Description of Diversity Variations of the Neogene Planktonic Foraminiferal Lineages and its Paleoceanographic Implication

HR: 1340h
AN: PP33A-1542 [Abstracts]
TI: A Factorial Description of Diversity Variations of the Neogene Planktonic Foraminiferal Lineages and its Paleoceanographic Implication
AU: * Wei, K
EM: weiky@ntu.edu.tw
AF: Dept. of Geosciences, National Taiwan University, PO Box 13-318, Taipei, 106 Taiwan
AB: The species diversities of the 24 planktonic foraminiferal lineages established by Kennett and Srinivasan (1983) were analyzed with a Q-mode factor analysis. The analysis led to recognition of three diversity associations, named as Early, Middle and Late Associations. The three associations are considered to be three idealized ťend membersÝ peaked at Early Miocene, Middle Miocene and Pliocene, respectively. Trajectory of factor loadings of the three associations through the Neogene indicates that major changes in faunal composition took place during 18-15 Ma (Upper N6 V N9), 13-10 Ma (N12-N15), and 7-4 Ma (N17-N19). The times of these three major faunal changes are consistent with the intervals of high species turnover in Neogene planktonic foraminifera documented by Wei and Kennett (1986). Based upon each lineageÝs contribution (factor score) to the three associations, the 24 lineages can be grouped into five faunas: evergreen fauna, early fauna, middle fauna, and late fauna, and miscellaneous fauna. Those in the evergreen fauna play major roles in at least two diversity associations whereas the miscellaneous fauna comprises lineages of low diversities. Lineages in the early, middle and late fauna all enjoyed high speciation rates during the early Miocene, but exhibited different diversification rates afterwards, and therefore assumed successive dominance through the Neogene. The morphological traits and ecological strategies of the various lineages in these five faunas may reveal clues for understanding the modulation of paleoceanographic conditions on planktonic foraminiferal evolution.
DE: 3030 Micropaleontology (0459, 4944)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4950 Paleoecology
DE: 4999 General or miscellaneous
DE: 9605 Neogene
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005