Calcite saturation and dissolution index of core-top sediment samples from the Ontong Java Plateau, Mid-Atlantic Ridge, the Caribbean and the Ceara Rise, the Indian Ocean, the Ninety-East Ridge and from the east of Madagascar

DOI

X-ray computed tomography (CT) provides an insight into the progression of dissolution in the tests of planktonic foraminifera. Four species of foraminifera (G. ruber [white], G. sacculifer, N. dutertrei and P. obliquiloculata) from Pacific, Atlantic and Indian Ocean core-top samples were examined by CT and SEM. Inner chamber walls began to dissolve at Delta[CO32-] values of 12-14 µmol/kg. Close to the calcite saturation horizon, dissolution and precipitation of calcite may occur simultaneously. Inner calcite of G. sacculifer, N. dutertrei and P. obliquiloculata from such sites appeared altered or replaced, whereas outer crust calcite was dense with no pores. Unlike the other species, there was no distinction between inner and outer calcite in CT scans of G. ruber. Empty calcite crusts of N. dutertrei and P. obliquiloculata were most resistant to dissolution and were present in samples where Delta[CO32-] ~ -20 µmol/kg. Five stages of preservation were identified in CT scans, and an empirical dissolution index, XDX, was established. XDX appears to be insensitive to initial test mass. Mass loss in response to dissolution was similar between species and sites at ~ 0.4 µg/µmol/kg. We provide calibrations to estimate Delta[CO3**2-] and initial test mass from XDX.

Supplement to: Johnstone, Heather J H; Schulz, Michael; Barker, Stephen; Elderfield, Henry (2010): Inside story: An X-ray computed tomography method for assessing dissolution in the tests of planktonic foraminifera. Marine Micropaleontology, 77(1-2), 58-70

Identifier
DOI https://doi.org/10.1594/PANGAEA.756133
Related Identifier https://doi.org/10.1016/j.marmicro.2010.07.004
Related Identifier https://nbn-resolving.org/urn:nbn:de:gbv:46-00101815-15
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.756133
Provenance
Creator Johnstone, Heather J H ORCID logo; Schulz, Michael ORCID logo; Barker, Stephen ORCID logo; Elderfield, Henry
Publisher PANGAEA
Publication Year 2010
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (-67.047W, -31.340S, 162.735E, 18.933N); Brazil Basin; Ceara Rise; Mid Atlantic Ridge; Pacific; Ontong Java Plateau; West Indian Ocean
Temporal Coverage Begin 1971-03-20T00:00:00Z
Temporal Coverage End 1997-04-04T13:54:00Z