Anomalously low radiocarbon content of modern n-alkanes
| Autor: | Elizabeth A. Yanuskiewicz, Chad S. Lane, Ralph N. Mead, Sally P. Horn |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
chemistry.chemical_classification
010504 meteorology & atmospheric sciences Stable isotope ratio Macrofossil Sediment Fractionation 010502 geochemistry & geophysics 01 natural sciences law.invention chemistry Geochemistry and Petrology law Lipid biosynthesis Environmental chemistry Organic matter Sedimentary rock Radiocarbon dating 0105 earth and related environmental sciences |
| Zdroj: | Organic Geochemistry. 152:104170 |
| ISSN: | 0146-6380 |
| DOI: | 10.1016/j.orggeochem.2020.104170 |
| Popis: | Compound-specific radiocarbon (14C) ages of lipid biomarkers commonly pre-date co-occurring macrofossils or sediment matrices in lacustrine and marine sedimentary sequences. Hypothetically, this age offset is the result of long residence and transport times of organic matter in the terrestrial realm and is referred to as ‘pre-aging’. Here we measure the 14C content of n-alkanes extracted from living leaf tissue of six different plant species. In all samples, the modern n-alkanes contained anomalously low 14C content resulting in apparent radiocarbon ages ranging from ∼ 530 to 1580 cal yr B.P. while bulk tissue samples yielded the expected modern 14C ages. These results indicate a potentially strong fractionation against 14C during lipid biosynthesis also documented for 13C and 2H stable isotope systems. This fractionation could, at least partially, explain observed age offsets between lipid biomarkers and co-occurring sediments. |
| Databáze: | OpenAIRE |
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