Helen K. Coxall, Amy P. Jones, Tom Dunkley Jones, Paul N. Pearson
This data set involves geochemical paleoceanographic proxy records from a borehole drilled in the Nanggulan region of central Java, Indonesia, and includes stable isotope ratios (δ¹⁸O and δ¹³C) measured on microscopic marine fossil plankton shells.
The 'Nanggulan Section' is a geological sequence of predominantly marine sediments with interbedded volcanic deposits of Eocene-Oligocene age, now uplifted on to land. The records span the time period between ca. 31 – 35.5 million years ago, a phase of geological time of significant interest to climate scientists because it marks the initiation of continental scale glaciation on Antarctica.
Java is of special importance because this region today, and in the past, sits in the Indo-Pacific warm pool, where the warmest sea surface temperatures for the whole planet are found. One question we can answer with these data is how much warmer was the warm-pool under Eocene greenhouse climate conditions.
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Citation
Helen K. Coxall, Amy P. Jones, Tom Dunkley Jones, Paul N. Pearson (2021) Eocene-Oligocene age planktonic and benthic foraminifera oxygen and carbon stable isotopes from the NKK-1 borehole, central Java. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/coxall-2021-java-1
References
Coxall HK, Dunkley Jones T, Jones AP, Lunt P, MacMillan I, Marliyani GI, Nicholas CJ, O’Halloran A, Piga E, Sanyoto P, Rahardjo W, Pearson PN (2021) The Eocene−Oligocene Transition in Nanggulan, Java: lithostratigraphy, biostratigraphy and foraminiferal stable isotopes. Journal of the Geological Society. https://doi.org/10.1144/jgs2021-006
Data description
The data set comprises an xlsx spreadsheet file containing carbon and oxygen stable isotope measurements (δ¹⁸O and δ¹³C), with sample IDs, measured subsurface depths and the interpreted sample age in millions of years ago. The same data are also provided in a csv file with utf-8 character encoding.
δ¹⁸O and δ¹³C were measured using a gas source mass spectrometer at Cardiff University, UK. The measurements were made on the calcium carbonate shells of time-ordered samples of two species of fossil foraminifera: (1) epifaunal benthic (seafloor-living) Cibicidoides spp. and (2) planktonic (lived at the ocean surface) Turborotalia ampliapertura.
Comments
Please, cite the study by Coxall et al. (2021) when using this dataset.
The data can be used for identifying the signal of Antarctic glaciation, which can be correlated globally to similar records from other sites, and for reconstructing the local ocean-climate conditions, including sea surface temperature, patterns of sea surface salinity, ocean nutrients, ocean circulation and the strength of ocean stratification.
Location of NKK-1 borehole, Kali Kunir, Nanggulan Province, Central Java, Indonesia: 7.73844° S, 110.18574° E.