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Climate change, a global challenge for human beings, is in the long term best documented through archaeological research. As this has shown, some cold reversal events, like Last Glacial Maximum and YD, greatly impacted of human behavior in mid-latitude areas of the northern hemisphere. A general recognition on how these events affected those in low latitude areas is yet to be determined. Previous studies have suggested that cold reversal events had a limited impact on humans in the latter parts of the world. This account discusses the effect of the YD on human behavior in a subtropical region, based on isotope analyses, and samples both faunal and artificial from the late Pleistocene site of Zhongshan in the Bubing Basin, Guangxi. During the YD, the environment became more open, and the consumption of aquatic resources increased. Polished stone artefacts first occurred in this period, probably for finer food processing. Our study highlights the significant impact of the YD on the ecology and human behavior in this subtropical region. [ABSTRACT FROM AUTHOR]

In current palaeodietary research, gelatinization is the main method to extract insoluble collagen (ISC) from ancient bones. However, the degradation products of ISC, i.e., soluble collagen (SC), is often neglected and abandoned. In this work, we try to separate the extracts of ancient bones using gel chromatography and compare the contents of carbon and nitrogen, atomic C/N ratio, and stable carbon and nitrogen isotopic values of the extracts from three peaks to determine which peak can be attributed to SC. At last, the potential application of SC in palaeodietary research is discussed based on the comparison of stable isotopic values between ISC and SC. Among the three peaks, the second with the retention time between 17.5 min and 27.5 min had the most broad peak shape, indicating that the molecular weights of proteins collected were most variable. Besides, the contents of carbon and nitrogen and atomic C/N ratio of extracts in this peak were closest to the corresponding ISC. Based on the above, we conclude that the extract in second peak is SC. More important, the δC and δN values of ISC and SC are very similar. For ISC and SC with atomic C/N ratios within the normal range (2.9-3.6), the mean difference of δC value was only (0.3±0.2)‰ ( n=2) while δN value was (0.6±0.1)‰ ( n=2). Although the atomic C/N ratios of some SC are slightly beyond the normal range, the mean differences of δC and δN values were still only (0.4±0.1)‰ and (0.3±0)‰ ( n=2) respectively. These isotopic differences are quite below the isotope fractionation in one trophic level ( δC values of 1‰-1.5‰ and δN values of 3‰-5‰), suggesting that SC had great application potentials in palaeodietary research. [ABSTRACT FROM AUTHOR]

Historical records and archaeological remains indicate that the Chinese agricultural economy changed significantly from the Warring States (475-221 BC) to Han Dynasties (206 BC-220 AD), i.e., from rice-millet based agriculture to rice-millet-wheat based agriculture. However, the variation of human diets and the inner relationship between human diets and the agricultural transition during this period remain poorly understood. In this paper, the C and N stable isotopes from human and animal bones at the Shenmingpu site (SMPS), Xichuan County, Henan Province were analyzed. If some outliers (M34, M36, M102) were excluded, the mean δC value ((−16.7±0.8)‰, n=15) of humans in Han Dynasties was dramatically lower than that in the Warring States ((−12.7±0.8)‰, n=14), indicating that the cultivation of rice and wheat, especially wheat, had been more widely popularized in Han Dynasties. Meanwhile, the range of δN values of humans (6.6‰-9.3‰) in Han Dynasties was narrower than that of the Warring States (6.2‰-10.4‰), suggesting that the animal protein resources in human foods during Han Dynasties were more concentrated. The transition of human diets and the close relationship with the change of agricultural economy in SMPS were due to more stable society, the carryout of new agricultural policies, and the emergence of new agricultural tools in Han Dynasties [ABSTRACT FROM AUTHOR]