Investigating Subantarctic <sup>14</sup>C Ages of Different Peat Components: Site and Sample Selection for Developing Robust Age Models in Dynamic Landscapes

Thomas, ZA; Turney, CSM; Hogg, A; Williams, AN; Fogwill, CJ

Investigating Subantarctic <sup>14</sup>C Ages of Different Peat Components: Site and Sample Selection for Developing Robust Age Models in Dynamic Landscapes

Thomas, ZA Turney, CSM Hogg, A Williams, AN Fogwill, CJ

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Publisher:: Cambridge University Press (CUP)
Publication Type:: Journal Article
Citation:: Radiocarbon, 2019, 61, (4), pp. 1009-1027
Issue Date:: 2019-08-01

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Field	Value	Language
dc.contributor.author	Thomas, ZA
dc.contributor.author	Turney, CSM
dc.contributor.author	Hogg, A
dc.contributor.author	Williams, AN
dc.contributor.author	Fogwill, CJ
dc.date.accessioned	2022-01-11T06:59:45Z
dc.date.available	2022-01-11T06:59:45Z
dc.date.issued	2019-08-01
dc.identifier.citation	Radiocarbon, 2019, 61, (4), pp. 1009-1027
dc.identifier.issn	0033-8222
dc.identifier.issn	1945-5755
dc.identifier.uri	http://hdl.handle.net/10453/152919
dc.description.abstract	Precise radiocarbon (14C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework.
dc.language	en
dc.publisher	Cambridge University Press (CUP)
dc.relation	http://purl.org/au-research/grants/arc/FL100100195
dc.relation	http://purl.org/au-research/grants/arc/DP130104156
dc.relation.ispartof	Radiocarbon
dc.relation.isbasedon	10.1017/RDC.2019.54
dc.rights	info:eu-repo/semantics/closedAccess
dc.subject	0402 Geochemistry, 0406 Physical Geography and Environmental Geoscience, 2101 Archaeology
dc.subject.classification	Paleontology
dc.title	Investigating Subantarctic <sup>14</sup>C Ages of Different Peat Components: Site and Sample Selection for Developing Robust Age Models in Dynamic Landscapes
dc.type	Journal Article
utslib.citation.volume	61
utslib.for	0402 Geochemistry
utslib.for	0406 Physical Geography and Environmental Geoscience
utslib.for	2101 Archaeology
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/DVC (Research)
utslib.copyright.status	closed_access	*
dc.date.updated	2022-01-11T06:59:44Z
pubs.issue	4
pubs.publication-status	Published
pubs.volume	61
utslib.citation.issue	4

Abstract:

Precise radiocarbon (14C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework.

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http://hdl.handle.net/10453/152919