Table S3.

Leaching experiments

Sample name	Leaching order	Lab	14C (BP)
			14C age	Error (2σ)
DL 13_4	First leaching	Xi'an	8,940	37
DL 13_4	Second leaching	Xi'an	9,030	37
DL 13_4	Third leaching	Xi'an	9,050	51
DL 15_3	First leaching	Xi'an	11,940	44
DL 15_3	Second leaching	Xi'an	11,900	42
DL 15_3	Third leaching	Xi'an	12,010	42

Results of leaching experiments on two carbonate shell samples. Later leaches generally produced slightly older ages, suggesting a small amount of easily dissolved contaminating carbonate phase in some samples. OD, overdispersion.