Data for Quantitative estimation of shell carbon deposition in terrestrial mollusks in northern China over 20,000 years

These sites were chosen based on their representation of main topography, land-uses and vegetation types, and were evenly distributed in space. The sampling involved four 0.5m× 0.5m subplots, and individual mollusks were selected using a visual search and extraction from a 3–5 cm-thick sample of litter and soil at each site.

Carbon contributes 12g for every 100g of shell, or 12% of overall shell mass. The shells were then weighed, and the carbon content of carbonate deposition through mollusk shell development (CDMS) was calculated using the formula CDMS = (W×95%×12%)/10, where W is the shell weight in grams per square meter in each modern soil sample. This calculation takes into account the amount of carbon deposited, which is 12% of 1g of shell carbonate, and converts the weight from grams per square meter to grams per square meter per year.