The stratigraphical relationship between planktonic and larger benthic foraminifera in Middle Miocene to Lower Pliocene carbonate facies of Sulawesi, Indonesia

Abstract

The Tacipi Formation of Sulawesi was deposited during the late middle Miocene to early Pliocene in a large area of shal- low water, marine carbonate production with deeper water sediments deposited to the north. A detailed biostratigraphical study of 580 samples from 58 measured outcrop sections has led to an understanding of sequence stratigraphic and facies relationships of Cenozoic carbonates in Sulawesi, their importance as the product and record of climatic/oceanic conditions and interchange in tropical/subtropical inner shelf environments, and their role as hydrocarbon reservoirs. Fifteen larger benthic foraminifera species are described and illus- trated with one newly proposed taxon: Lepidocyclina pillaria. Analysis of the larger benthic foraminifera in relationship to the plank- tonic foraminifera allows correlation of the larger foraminiferal assemblage zones (letter stages) of the Far East with the N zones of the Neogene based on planktonic foraminiferal evolution patterns. The co-occurrence and recognition of planktonic foraminifera and larger benthic foraminifera species in the same thin sections is a rare opportunity for correlating the biostratigraphic frameworks based on these two groups and is of regional stratigraphic importance. This has resulted in the refinement of the biostratigraphic ranges of the larger ben- thic foraminifera Katacyclocypeus and Flosculinella, and enlargement of our knowledge about the Tg and Th letter stages.