Palaeoecology of Oligo-Miocene larger Foraminiferida, Australia

Eight fossil associations of larger foraminiferids have been recognised in Western Australia. Each represents a certain environment. Three of these associations were typical of seagrass communities at depths of less than 12 metres: the Lepidocyclina (Eulepidina) ephippioides Heterostegina borneensis association in oceanic salinities but in sheltered situations, the Lepidocyclina (Nephrolepidina) howchini Cycloclypeus eidae/carpenteri association in the same salinities but in open situations, and the Lepidocyclina (Nephrolepidina) howchini Marginopora vertebralis association in metahaline salinities. Two associations were typical of high energy sandy substrates in depths of less than 30 metres: the Operculina complanata Gypsina howchini association in oceanic salinities and the Austrotrillina howchini Flosculinella bontangensis association in metahaline salinities. Three associations were typical of open situations with oceanic salinities. The Lepidocyclina (Eulepidina) badjirraensis Cycloclypeus eidae association lived in waters deeper than 12 metres; its lower boundary overlapped the Cycloclypeus eidae Operculina complanata association, which ranged to near the base of the euphotic zone at depths near 120 metres. The Operculina complanata smaller benthonic foraminiferal association was typical of depths near 120 metres or greater. G. C. H. Chaproniere, Bureau of Mineral Resources, Canberra City, A.C.T., Australia 2601; received 22 May 1975.