Abstract:
This data set presents contents of the clay minerals smectite, illite, chlorite and kaolinite analysed on the clay fraction (<2 micrometer) of seafloor surface sediments. The sediments were recovered with a mega-corer (MC), box corer (BC), kasten corer (KC) or jumbo gravity corer (JGC) on the Amundsen Sea continental shelf in the vicinity of Thwaites Glacier and Pine Island Glacier. Sediment cores were collected during cruises NBP1902 (Jan-Mar 2019) and NBP2002 (Jan-Mar 2020) with RV/IB Nathaniel B. Palmer as part of the Thwaites Offshore Research (THOR) project on behalf of the International Thwaites Glacier Collaboration (ITGC) programme. The clay mineral contents are given in percentages and subbottom depth in centimetres (cm).
NERC grant NE/S006664/1 and NSFPLR grant no. 1738942. This data was collected as part of the NERC-NSF funded International Thwaites Glacier Collaboration (ITGC) program.
Keywords:
Amundsen Sea, Clay minerals, International Thwaites Glacier Collaboration (ITGC), Thwaites Offshore Research (THOR)
Hillenbrand, C., & Ehrmann, W. (2023). Clay mineral composition of seafloor surface sediments from the Amundsen Sea continental shelf, West Antarctica (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/e8198dd3-ea60-4a4c-9975-d9c1695820fe
| Access Constraints: | This dataset is under embargo until December 2025, when it will be made freely available. Before the end of the embargo, referees may access the dataset for review purposes using a login and password provided by the PDC. |
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| Use Constraints: | This data is covered by a UK Open Government Licence v3 (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). |
| Creation Date: | 2023-06-29 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Dr Claus-Dieter Hillenbrand |
| Role(s) | Investigator, Technical Contact |
| Organisation | British Antarctic Survey |
| Name | Prof Werner Ehrmann |
| Role(s) | Investigator |
| Organisation | University of Leipzig |
| Parent Dataset: | N/A |
| Reference: | Biscaye, P.E., 1964. Distinction between kaolinite and chlorite in recent sediments by X-ray diffraction. Am. Mineral. 49, 1281-1289. Biscaye, P.E., 1965. Mineralogy and sedimentation of recent deep-sea clay in the Atlantic Ocean and adjacent seas and oceans. Geol. Soc. Am. Bull. 76, 803-832. Petschick, R., 2010. MacDiff 4.2.6. https://www.uni-frankfurt.de/69528130/Petschick_MacOS_Software. Petschick, R., Kuhn, G. & Gingele, F., 1996. Clay mineral distribution in surface sediments of the South Atlantic: sources, transport, and relation to oceanography. Mar. Geol. 130, 203-229. |
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| Quality: | By preparing, analysing and evaluating samples six times, a standard deviation of c. 1 percentage was obtained for the concentrations of smectite, chlorite and kaolinite, and of c. 1.5 percentage for illite. | |
| Lineage: | The sediments were recovered with a mega-corer (MC), box corer (BC), kasten corer (KC) or jumbo gravity corer (JGC) on the Amundsen Sea continental shelf in the vicinity of Thwaites Glacier and Pine Island Glacier. Sediment cores were collected during cruises NBP1902 (Jan-Mar 2019) and NBP2002 (Jan-Mar 2020) with RV/IB Nathaniel B. Palmer. The clay fraction (less than 2 micrometers) was separated from the bulk sediment in settling tubes, and 40 mg clay suspension was mixed with 1 ml of an internal standard (0.04 percent MoS2 suspension). The samples were then mounted as texturally oriented aggregates by rapidly filtering the suspension through a membrane filter (0.20 micrometer pore width). The filter cakes were dried at 50 degrees Celsius, fixed on aluminium tiles and exposed to ethylene glycol vapour at a temperature of 60 degrees Celsius for at least 18 h immediately before the X-ray analyses. The measurements were conducted on a diffractometer system Rigaku New Miniflex with Cobalt K-alpha radiation (30 kV, 15 mA). First, the samples were X-rayed in the range 3-40 degree2theta, with a step size of 0.02 degree2theta and a measuring time of two seconds per step. Then, the range 27.5-30.6 degree2theta was X-rayed with a step size of 0.01 degree 2 theta and a measuring time of four seconds per step in order to better resolve the (002) peak of kaolinite and the (004) peak of chlorite. The X-ray diffractograms were evaluated using the interactive ''MacDiff'' software (Petschick 2010, Petschick et al. 1996). The main clay mineral groups were identified by their basal reflections at 16.5 Angstrom (smectite, after glycolisation), 10 and 5 Angstrom (illite), 14.2, 7, 4.72 and 3.54 Angstrom (chlorite), and 7 and 3.58 Angstrom (kaolinite) after the diffractograms had been adjusted to the MoS2 peak at 6.15 Angstrom. For semi-quantitative evaluations of the clay mineral assemblages, empirically estimated weighting factors on the integrated peak areas of the individual clay mineral reflections were used (Biscaye 1964, 1965). |
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| Temporal Coverage: | |
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| Start Date | 2019-02-09 |
| End Date | 2019-03-13 |
| Start Date | 2020-02-06 |
| End Date | 2020-03-12 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -75.11329 |
| Northernmost | -73.80046 |
| Longitude | |
| Westernmost | -107.8639 |
| Easternmost | -100.5979 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | 266 |
| Max Depth | 1082 |
| Data Resolution: | |
| Latitude Resolution | N/A |
| Longitude Resolution | N/A |
| Horizontal Resolution Range | N/A |
| Vertical Resolution | Depth 1cm |
| Vertical Resolution Range | N/A |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Core |
| Detailed Location | Amundsen Sea |
| Data Collection: | A diffractometer system, Rigaku New Miniflex with Cobalt-K-alpha radiation (30 kV, 15 mA), was used for the X-raying. The diffractograms were analysed with the interactive ''MacDiff'' (v. 4.2.5) software (Petschick 2010). |
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| Distribution: | |
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| Distribution Media | N/A |
| Distribution Size | 1 file, 3 KB |
| Distribution Format | N/A |
| Fees | N/A |
| Data Storage: | The values under the 'Site' variable contain codes relating to the type of coring undertaken: MC = mega corer BC = box corer KC = kasten corer JGC = jumbo gravity corer |