Palaeodietary Study On Human And Faunal Remains From Broze-Iron Age Hami Basin And Its Subsistence Implication

Being part of central Asia,Xinjiang links the two most important origin centers from east and west and embraces influences from all directions.Communications across the entire Eurasia continent became frequent and lasting taking advantage of horses and wheels especially after the Bronze Age.People with differed technologies and resources blended and thus changed their original life patterns,choice over food constitute one of the most significant aspects of which.Locates on the crossroad,Xinjiang can never isolate itself from being deeply influenced.Exchange of cultures and resources spatially reallocate foods and change people's intrinsical food variety,making changable availiablity of different periods.By restricting plants growing there environmental condition is the other vital facter apart from time determining prehistoric food choice,eventually adaptive subsistence strategy.Hami Basin locates on the eastern end of Tianshan Mts.with almost every westward routes from the central China and Hexi Corridor passing through.Except for its spatial importance,Hami has diversified natural environment is Xinjiang in miniature,make it an ideal spot studying food sutructure and subsistence stategy under certain circumstances of prehistoric Xinjiang occupants.This work take three Bronze-Iron Age sites namely Liushugou site,Ya'er cemetery and Aisikexiaernan cemetery from Hami Basin as examples,thoroughly sample the faunal and human bones exposed,identify and record,and then extract their collagen for stable isotopic analysis.364 set of isotope composition was produced in total not counting the ones too poorly preserved and couldn't produce enough collagen for testing.Among the samples,216 were human and the left 148 belonged to fauna.Reconstruct the prehistoric diet in terms of the isotopic composition of human and faunal remains,and further discuss their subsistence economy and social structure,try to understand their interaction with environment.The following are main results of this work:?1?The Liushugou site?3.5³.0 cal ka BP?locates on one of the southern mouths of eastern Tianshan Mts.,dates back to the Bronze Age,consists of burial and residential spaces.The stable isotopic analysis of faunal and human bones of this site reveals that:Animal protein took high proportion in the diet of this population,except two extremes,as ¹⁵N shows high enrichment in the collagen,with mean?¹⁵N value of13.4±1.5‰?n=44?,ranging from 12.4 to 15.1‰,indicating substantial high quality animal food intake;The?¹³C values ranged from-19.1 to-17.2‰with a mean of-18.1±0.4‰?n=46?,combined with the fact that test flotation found no C₄ plant,suggesting nearly nothing C₄ based food was consumed,that almost all the vegetation resource they intook come from C₃ plants,demonstrating the population of Liushugou had a stable food structure composed mostly with C₃ based animal products;Abundant faunal bones were also exposed,most of them herbivores with sheep/goat and cattle leading in number,implying their importance in the community's daily life,mammals like horses,boars,deer,antelopes and gorals were also found at this site as well as hare the rodent,like people had a diet come mostly from C₃ food,the faunal remains of this site also showed a C₃ sourced food intake with?¹³C values ranging from-20.0 to-15.8‰,with a mean of-18.3±0.8‰?n=55?,except three outliers whose?¹³C values indicated some C₄ plants signal;the?¹⁵N values of animals had a large range,from 5.5 to 13.4‰,with mean of 8.4±1.6‰?n=58?,what should be noticed is that the omnivore of boars showed no isotopic difference from the remaining herbivore counterparts,demonstrating that like herbivores,the boars had a diet based on C₃ plants,might also suggesting the lack of animal protein in the surrounding environment;Judging from the isotopic result and the environment of this site,it is believed that the Liushugou community highly reliant on pasturing,with hunting and occasionally changing goods with neighboring populations as supplementary activities,the highly clustered isotope distribution of this community also leading to a conclusion that the society was in primary hierarchical process.?2?The Ya'er cemetery?3.0².3 cal ka BP?locates in the western part of Hami Basin with Baiyang River flowing nearby is an Iron Age site.The stable isotopic analysis of human and faunal remains of this cemetery reveals that:Both C₃ and C₄food were consumed by the occupants of this site,with human bone?¹³C values ranging from-18.2 to-13.1‰meaning-15.7±1.0‰?n=127?,indicating that the population intook some C₄ food more or less;The?¹⁵N values of human bone collagen ranged from 12.1 to 16.5‰,with a mean of 14.0±0.8‰?n=127?,demonstrating the substantial animal protein consumption of this population;This cemetery was in use for nearly one millennium,but the isotope composition of four phases stayed steady and proved the diet stability during different periods of occupation;Juveniles were isotopically distinguished from that of adults,with the former enriched both in ¹³C and ¹⁵N;The isotopes tend to be similar between individuals sharing one tomb,highly implying that they were family members;Sheep/goats as the most popular funerary objects had?¹³C values ranging from-17.8to-14.1‰,with mean value of-16.4±1.0‰?n=24?,suggesting some C₄ plant intake while the?¹⁵N values ranged from 6.8 to 10.7‰,with mean of 8.7±1.0‰?n=24?;Three horse samples showed differed feeding strategy consumed different proportion of C₄ plants;Take sheep/goats as the major animal food,the stepwise of5.3‰for?¹⁵N value between sheep/goat and human may have hid some other ¹⁵N enriched animal source which showed no clue in the cemetery;The scattered isotopes of this population suggest diversified food resource and also the sophisticated social structure,expressed as different amount of C₄ food in diet.?3?The Aisikexiaernan cemetery?2.7².3 cal ka BP?,also an Iron Age site,locates to the southwest of Ya'er cemetery at lower Baiyang River drainage.Stable isotopic analysis of bones exposed from this site reveals that:A proportion of this population intook certain C₄ food with?¹³C values ranged from-19.2 to-14.4‰and produced a mean of-17.3±0.9‰?n=43?,while their?¹⁵N values ranged from 12.0to 18.5‰,with mean value of 14.5±1.0‰?n=43?,indicating a animal protein dominated diet;Individuals sharing one grave tend to have similar isotopic composition which implying their similar food intake and thus highly probability of family members;Sheep/goats as funerary objects had?¹³C values ranging from-18.7to-9.2‰,with mean value of-13.7±2.1‰?n=62?,indicating a C₄-C₃ mixed diet,could have had massive millet byproduct,while their?¹⁵N values ranged from 6.0 to16.3‰,with mean value of 11.0±1.6‰?n=62?,the enriched ¹⁵N signal could either be the result of arid ecology or substantial crop product consumption,reflecting also the intensive human intervention;The significant linear relationship between?¹³C and?¹⁵N values for both human and sheep/goat samples demonstrating a stratified society with differed C₄ food accession.?4?On the basis of the isotopic composition,combined with their natural environment,time of occupations,archaeological features and other supplementary information,the following conclusions were draw:The Liushugou community reliant more on animal resource they were pasturing while the Ya'er and Aisikexiaernan occupants expanded their living on crop farming too,and it was mostly the different environment led to this subsistence variation not their time difference;Mountain and oasis gave two different landscapes and thus determined people living in which have different options for living,with people from the former environment herding and hunting,and latter ones herding,hunting and growing;Two ways of living led to differed social complexity and also proved the coexisting of mountainous system and oases system in this region for at least 2000 years,and each has distinguished isotope composition.Integrated with published data from culturally related contemporary sites of this region,a dietary shift from Bronze Age to Iron Age is observed,characterized by distinct isotopic composition from different sites during Bronze Age and convergent ones during Iron Age,implying deep subsistence strategy change.