Citation:

0959683611434223

Name: Radiocarbon ages, diatom abundance and laminae description of sediment core MD03-2597
Published: 2012
License: https://creativecommons.org/licenses/by/3.0/

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Published: 2012 (exact date unknown) • DOI registered: 2013-02-28

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Abstract:

Laminated sediments are unique archives of palaeoenvironmental and palaeoceanographic conditions, recording changes on seasonal and interannual timescales. Diatom-rich laminated marine sediments are examined from Dumont d'Urville Trough, East Antarctic Margin, to determine changes in environmental conditions on the continental shelf from 1136 to 3122 cal. yr BP. Scanning electron microscope backscattered electron imagery (BSEI) and secondary electron imagery are used to analyse diatom assemblages from laminations and to determine interlamina relationships. Diatom observations are quantified with conventional assemblage counts. Laminae are primarily classified according to visually dominant species identified in BSEI and, secondarily, by terrigenous content. Nine lamina types are identified and are characterized by: Hyalochaete Chaetoceros spp. resting spores (CRS); CRS and Fragilariopsis spp.; Fragilariopsis spp.; Corethron pennatum and Rhizosolenia spp.; C. pennatum; Rhizosolenia spp.; mixed diatom assemblage; Stellarima microtrias resting spores (RS), Porosira glacialis RS and Coscinodiscus bouvet; and P. glacialis RS. Formation of each lamina type is controlled by seasonal changes in sea ice cover, nutrient levels and water column stability. Quantitative diatom assemblage analysis revealed that each lamina type is dominated by CRS and Fragilariopsis sea ice taxa, indicating that sea ice cover was extensive and persistent in the late Holocene. However the lamina types indicate that the sea ice regime was not consistent throughout this period, notably that a relatively warmer period, ~3100 to 2500 cal. yr BP, was followed by cooling which resulted in an increase in year round sea ice by ~1100 cal. yr BP.

Project(s):

International Polar Year (2007-2008) (IPY)

Coverage:

Median Latitude: -66.412514 * Median Longitude: 140.420833 * South-bound Latitude: -66.414420 * West-bound Longitude: 140.419400 * North-bound Latitude: -66.412300 * East-bound Longitude: 140.421000

Date/Time Start: 2001-01-01T00:00:00 * Date/Time End: 2003-02-05T13:04:00

Comment:

Data extracted in the frame of a joint ICSTI/PANGAEA IPY effort, see http://doi.pangaea.de/10.1594/PANGAEA.150150

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

5 datasets

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Datasets listed in this publication series

Maddison, EJ; Pike, J; Dunbar, RG (2012): (Table 1) Radiocarbon ages for sediment cores MD03-2597, NBP01-01-JPC17B and NBP01-01-KC17B. https://doi.org/10.1594/PANGAEA.806331
Maddison, EJ; Pike, J; Dunbar, RG (2012): (Table 2b) Relative abundance of diatoms (Chaetoceros spp. resting spore-free) in sediment core MD03-2597. https://doi.org/10.1594/PANGAEA.806333
Maddison, EJ; Pike, J; Dunbar, RG (2012): (Table 2a) Relative abundance of diatoms in sediment core MD03-2597. https://doi.org/10.1594/PANGAEA.806332
Maddison, EJ; Pike, J; Dunbar, RG (2012): (Table 3) Lamina types, thickness and occurrence in sediment core MD03-2597. https://doi.org/10.1594/PANGAEA.806334
Maddison, EJ; Pike, J; Dunbar, RG (2012): (Table 4) Description of visually conspicuous diatom species in laminae of sediment core MD03-2597. https://doi.org/10.1594/PANGAEA.806335