The influence of agriculture in the process of population integration and cultural interaction during the Eastern Zhou Period in central-south, Inner Mongolia: Carbon and nitrogen stable isotope analysis of human bones from the Dabaoshan cemetery, Helingee

Central-south Inner Mongolia, China, is highly sensitive to the cultural interactions between sedentary agriculturalists and nomadic pastoralists during the Eastern Zhou Period(770–256 BC). The previous pattern of multiple cultures and diverse ethnic groups has been transformed to the increasingly dominated cultural system of Central Plain since the middle and late Warring States Period, when the states of Zhao and Qin have conquered the most parts of central-south Inner Mongolia.However, the variation of subsistence strategies during this historical process has never been evaluated. Particularly, as the typical representative of Central Plain cultures, the effect of intensive millet agriculture is still unknown in the process of population integration and culture interaction. Thus, to explore the shift of subsistence pattern, carbon and nitrogen stable isotope analysis of bone collagen from Dabaoshan site(410–180 BC) have been performed. The isotopic result indicates a large amount of C_4-based animal protein consumed by Dabaoshan humans. According to the archaeological backgrounds, we propose the Dabaoshan persons intensively relied on the millet agriculture and developed the agro-pastoral economy, which hinted the comprehensive influences from Central plain civilizations in late Warring States Period. Further compared with other published isotopic data in the same region during different periods, we suggest the millet agriculture has played the positive role in the process of population integration and culture fusion in central-south Inner Mongolia during the Eastern Zhou Period.

Spatial distributions of organic carbon and nitrogen and their isotopic compositions in sediments of the Changjiang Estuary and its adjacent sea area

The spatial distribution patterns of total organic carbon and total nitrogen show significant correlations with currents of the East China Sea Shelf. Corresponding to distributions of these currents, the study area could be divided into four different parts. Total organic carbon, total nitrogen, and organic carbon and nitrogen stable isotopes in sediments show linear correlations with mean grain size, respectively, thus ＂grain size effect＂ is an important factor that influences their distributions. C/N ratios can reflect source information of organic matter to a certain degree. In contrast, nitrogen stable isotope shows different spatial distribution patterns with C/N and organic carbon stable isotope, according to their relationships and regional distributions. The highest contribution （up to 50%） of terrestrial organic carbon appears near the Changjiang Estuary with isolines projecting towards northeast, indicating the influence of the Changjiang dilution water. Terrestrial particulate organic matter suffers from effects of diagenesis, benthos and incessant inputting of dead organic matter of plankton, after depositing in seabed. Therefore, the contribution of terrestrial organic carbon to particulate organic matter is obviously greater than that to organic matter in sediments in the same place.

Distribution and Sources of Organic Matter in Surface Sediments of the Karachi Coast,Pakistan

Under the steadily intensifying human activities in coastal areas,it is crucial to distinguish the sources of organic matter(OM)in sediments for better understanding of the environmental change.In this study,25 surface sediments collected along the harbor and creeks areas off Karachi coast were used for total organic carbon(TOC),total nitrogen(TN),stable carbon(δ^(13)C)and nitrogen(δ^(15)N)isotopic compositions,phytoplankton biomarkers(brassicasterol,dinosterol and cholesterol)and glycerol dialkyl glycerol tetraethers(GDGTs)analyses,to trace the distribution of OM and identify its sources.TOC,TN,δ^(13)C,and δ^(15)N are in the range of 0.04% to 5.28%,0.01% to 0.57%,-17.55‰ to -26.31‰,and 2.83‰ to 6.04‰,respectively.C/N values range from 4.24 to 21.04.The δ^(13)C,δ^(15)N,C/N,BIT(Branched Isoprenoid Tetraether)index together with phytoplankton biomarkers show both marine and terrestrial OM input to the creeks and Harbor stations.In contrast,the stations from Western Coast indicate a marine source predominance.A clearly impact of human activities is seen from sediments near river mouths.

The subsistence patterns of the Shengedaliang site(-4,000 yr BP)revealed by stable carbon and nitrogen isotopes in northern Shaanxi,China

In order to explore subsistence patterns in northern Shaanxi Province around 4,000 yr BP,28 human and 24 animal bones from the Shengedaliang site were sampled for stable carbon and nitrogen isotope ratio analysis.The results show that most people primarily subsisted on C_4 resources,e.g.millet and millet-related animal products,despite the fact that there was some intake of C_3 plants by some individuals.Stable nitrogen isotope values indicate that there were differences in meat consumption between individuals at the site.Pigs were mainly foddered with millet and millet byproducts,as well as some cattle,according to their highδ^(13)C values.However,most cattle and the sheep/goats consumed wild C_3 plants at Shengedaliang.Our above findings indicates that subsistence patterns in northern Shaanxi around 4,000 yr BP were characterized by millet farming,while the grassland animal husbandry,e.g.cattle and sheep/goats raising,displayed very little contribution to local economy.The intensive millet farming in northern Shaanxi provided enough food for population growth,ensured the accumulation of wealth,and consequently accelerated social differentiation and complexity.