Stockholm university

Journal of the Geological Society article authored by Helen Coxall

New insights into the Indo-Pacific warmpool 34 million years ago. Research led by Helen Coxall describes a rich geological archive from cored sediments in central Java, Indonesia, that will answer questions about changes in the hottest part of the World's Ocean under past greenhouse climate conditions.

group of researchers standing behind a escavating site in the jungle with backets, tarpaulins, poles
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The Eocene−Oligocene transition in Nanggulan, Java:lithostratigraphy, biostratigraphy and foraminifera

Coxall, H. K., Jones, T. D., Jones, A. P., Lunt, P., MacMillan, I., Marliyani, G. I., Nicholas, C. J., O'Halloran, A., Piga, E., Sanyoto, P., Rahardjo, W., and Pearson, P. N., 2021, The Eocene−Oligocene transition in Nanggulan, Java: lithostratigraphy, biostratigraphy and foraminiferal stable isotopes: Journal of the Geological Society, p. jgs2021-2006.

Abstract: The Nanggulan section in south central Java comprises open marine sediments and volcanic deposits of Eocene–Oligocene age that accumulated in a marginal basin within the young Sunda Arc complex. A new borehole captures thestratigraphy and showcases the exceptional preservation of calcareous microfossils across an apparently complete Eocene–Oligocene Transition (EOT), a time interval significant for the initiation of continental-scale glaciation on Antarctica. Low-resolution benthic and planktonic foraminifera oxygen and carbon stable isotopes (δ18O andδ13C) record increasingδ18O andδ13C in the basal Oligocene, allowing correlation to global records. Isotopic values imply warm temperatures and relativelyhigh nutrients along the SE Java margin. The Nanggulan EOT is a valuable archive for reconstructing ocean–climate behaviourand plankton evolution and extinction in the Indo-Pacific Warm Pool. The borehole also adds to understanding of the earlystages of Sunda Arc volcanism.

Supplementary material:Supplementary figures, tables and appendices are available at