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Opal concentrations measured in sediment samples collected during the IN2017-V01 voyage of the RV Investigator

Created 13/03/2025

Updated 13/03/2025

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Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; (Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC), were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. Sediment samples were dried in an oven at 40°C and ground using a pestle and a mortar. Biogenic silica (or ‘opal’) analysis was carried out following modification of the protocol of Mortlock and Froelich (1989). About 30 mg of sediment was leached with 30 mL of 1M sodium carbonate (Na2CO3) for 5 hours at 80°C. Every hour, 1 mL of sample was removed and centrifuged at 10,000 rpm for 30 sec. A 200 µL aliquot was removed from the supernatant and diluted 50x with Milli-Q water for SiO2 determination by molybdate-blue spectrophotometry. A standard calibration was prepared by dilution of a SiO2 standard solution (sodium hexafluorosilicate, from 0 to 200 µM). The opal concentrations were calculated using the slope of the last three points of the dissolution curve (Demaster, 1981), or the changing slope part of the curve. References - Armand, L. K., O’Brien, P. E., Armbrecht, L., Baker, H., Caburlotto, A., Connell, T., … Young, A. (2018). Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report. ANU Research Publications. - Demaster, D. J. (1981). The supply and accumulation of silica in the marine environment. Geochimica et Cosmochimica Acta, 45, 1715–1732. - Mortlock, R. A., and Froelich, P. N. (1989). A simple method for the rapid determination of biogenic opal in pelagic marine sediments. Deep-Sea Research Part I, 36(9), 1415–1426.

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Field Value
Title Opal concentrations measured in sediment samples collected during the IN2017-V01 voyage of the RV Investigator
Language eng
Licence notspecified
Landing Page https://devweb.dga.links.com.au/data/dataset/dac47028-b20a-4534-a710-8041b3c3a03b
Contact Point
CSIRO Oceans & Atmosphere
metadata@aad.gov.au
Reference Period 14/01/2017 - 31/12/2020
Geospatial Coverage {"type": "Polygon", "coordinates": [[[115.0, -65.0], [120.0, -65.0], [120.0, -64.0], [115.0, -64.0], [115.0, -65.0]]]}
Data Portal data.gov.au

Data Source

This dataset was originally found on data.gov.au "Opal concentrations measured in sediment samples collected during the IN2017-V01 voyage of the RV Investigator". Please visit the source to access the original metadata of the dataset:
https://devweb.dga.links.com.au/data/dataset/opal-concentrations-measured-in-sediment-samples-collected-during-the-in2017-v01-voyage-of-the-