Compound‐Specific Radiocarbon Analysis of (Sub‐)Antarctic Coastal Marine Sediments—Potential and Challenges for Chronologies


Contact
Gerhard.Kuhn [ at ] awi.de

Abstract

In Antarctic and Subantarctic environments, 14C‐based age determination is often challenging due to unknown reservoir effects, low organic carbon contents of sediments, and high contributions of petrogenic (14C‐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 14C 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 14C‐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 14C 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 14C 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
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
ISI/Scopus peer-reviewed
Publication Status
Published
Eprint ID
53109
DOI 10.1029/2020pa003890

Cite as
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 , Paleoceanography and Paleoclimatology, 35 (10) . doi: 10.1029/2020pa003890


Share


Citation

Research Platforms

Campaigns


Actions
Edit Item Edit Item