Integrated planktonic foraminifera, Bolboforma and carbon isotope stratigraphy in a mid/early late Miocene carbonate ramp setting from the Acreide area (Sicily)

Taxa of Bolboforma, a marine calcareous microfossil group of uncertain orig in with affinities to protophytic algae, are generally used for biostratigr aphy of lower Eocene to lower Pleistocene marine sediments from high latitu des. Biostratigraphy based on Bolboforma has been applied only rarely to Eu ropean outcrop sections and very rarely to Mediterranean sections. Three Bo lboforma and two planktonic foraminifera events are identified and used to interpret the sedimentation rate of the 90 m of slope sediments from the Pa lazzolo Section, Palazzolo Acreide area (Sicily) and spanning the interval from 11.9 to approximately 10.5 Ma. Carbon isotope stratigraphy supports the age assigment based on Bolboforma and planktonic foraminifera. In particular, the sediments of the Palazzolo Section seem to record the latest pulse of the Monterey Event, a major pert urbation in the global carbon cycle related to global intensification of up welling. Expanded use of the Bolboforma may, thus, improve stratigraphy in outcroppi ng Miocene sequences in temperate regions, particularly in shallower water facies with poorly resolved planktonic foraminifera and nannofossil stratig raphy. (C) 2001 Elsevier Science B.V. All rights reserved.