The University of Arizona

Radiocarbon and Stable Carbon Isotope Analyses of Land Snails from the Chinese Loess Plateau: Environmental and Chronological Implications

Bing Xu, Zhaoyan Gu, Jingtai Han, Zongxiu Liu, Yunpeng Pei, Yanwu Lu, Naiqin Wu, Yongfu Chen

Abstract


Paired radiocarbon and stable carbon analyses have been carried out on aragonite shells and organic soft bodies of snails from the Chinese Loess Plateau in order to explore the possibility of using these kinds of samples as environmental and chronological indicators. Results show that the soft bodies exhibit 14C concentrations similar to those of plant leaves, indicating that carbon in the soft bodies is fixed from organic diets. The aragonite shells are depleted in 14C compared to the soft bodies due to ingestion of 14C-depleted carbonate. This depletion shows a consistent pattern across the Chinese Loess Plateau, implying a good potential for the snail shells to be applicable for 14C dating with a simple correction. The δ13C values measured for aragonite shells display a linear relationship with those obtained for the soft bodies with a constant offset. In addition, the carbon derived from organic diets accounts for more than 70% of the total shell carbon. This fact suggests that stable carbon isotope composition of aragonite shells mainly reflects that of organic diet, and could be used as a reliable indicator of paleodiet in the Chinese Loess Plateau.

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