Pleistocene to Holocene planktic foraminiferal biostratigraphy of the Coral Sea, offshore Queensland, Australia.

Brief description

Fifteen of 27 potential planktic foraminiferal biostratigraphic events from the latest Pliocene-Holocene have been examined; most of the early Pleistocene was not able to be studied because of a hiatus in the one core which penetrated through the Pleistocene into the top of the Pliocene. Four of these events have been recognised for the first time, and some have been used to establish a formal zonal and subzonal scheme for the region. Two new subzones are proposed, the Globigerinoides quadrilobatus fistulosus Subzone (for the basal part of Zone N.22) and the Bolliella praeadamsi Subzone (for the top part of Zone N.22). These changes have made necessary the redefinition of both the Globorotalia (Truncorotalia) crassaformis viola and the Globorotalia (Truncorotalia) crassaformis hessi Subzones. There is little evidence that changes in palaeoceanographic conditions are related to the faunal changes observed in the cores, although there are strong indications of reworking at some levels within some of the cores (such as late Miocene Zone N.17 in one core), which may have been related to sea-level fluctuations. The assemblages from the cores show a marked stability, with the faunas being dominated by spinose, oligotrophic taxa. Temperate water forms are either very rare or absent, whereas tropical and subtropical species are dominant. A single new species, Bolliella praeadamsi has been described because of its biostratigraphic utility. This species is an evolutionary intermediate between Bo. calida praecalida and Bo. adamsi.

Lineage

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