Universität zu Köln

Berg, S., Jivcov, S., Kusch, S., Kuhn, G., Wacker, L. and Rethemeyer, J. (2020). Compound-Specific Radiocarbon Analysis of (Sub-)Antarctic Coastal Marine Sediments-Potential and Challenges for Chronologies. Paleoceanogr. Paleoclimatology, 35 (10). WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 2572-4525

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Abstract

In Antarctic and Subantarctic environments, C-14-based age determination is often challenging due to unknown reservoir effects, low organic carbon contents of sediments, and high contributions of petrogenic (C-14-free) carbon in ice marginal settings. In this study, we evaluate possible benefits and challenges of compound-specific radiocarbon analysis (CSRA) as a tool for age determination of marine Antarctic and Subantarctic sediment sequences. We present a comprehensive data set of C-14 ages obtained on bulk organic carbon, carbonates, and on fatty acids (FA) from three coastal marine sediment cores from Subantarctic South Georgia and East Antarctica. Low molecular weight (LMW) FA represent the least C-14-depleted fraction, indicating that the phytoplankton-derived compounds can be a means of dating sediments. In contrast, vascular plant-derived high molecular weight FA are systematically depleted in C-14 relative to the low molecular weight homologues, reflecting processes such as soil formation/erosion in the catchment. Comparative age-depth models show significant differences, depending on the material used for the respective models. While the land plant-derived FA may lead to an overestimation of the actual sediment age, LMW FA reveal complex aquatic reservoir effects. Bulk sedimentary organic carbon C-14 ages likely provide appropriate age estimates in settings with low petrogenic carbon input in the Antarctic, whereas CSRA has the potential to produce improved age control in settings with high contributions of petrogenic carbon.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Berg, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jivcov, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kusch, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kuhn, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wacker, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rethemeyer, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-316178
DOI:	10.1029/2020PA003890
Journal or Publication Title:	Paleoceanogr. Paleoclimatology
Volume:	35
Number:	10
Date:	2020
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	2572-4525
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SOUTH GEORGIA; ICE-SHELF; ORGANIC-MATTER; METHANE SEEPAGE; EAST ANTARCTICA; RESERVOIR AGES; CUMBERLAND BAY; FATTY-ACIDS; PRYDZ BAY; ROSS SEA Multiple languages Geosciences, Multidisciplinary; Oceanography; Paleontology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/31617