丝绸之路东段青铜时代早期人类食谱重建及同位素数据解译

The history and influence of cultural exchange between east and west in Eurasia is a frontier science issue. East-West exchange connected the important agricultural origin centers-Southwest Asia and China-and was characterized by long-distance movements for metallurgy, livestock, crops, and ideas. Such exchange was more intensive and frequent during the second millennium BC (from 4000 BP to 3000 BP) than in earlier times. Recently, it is suggesting that the intercontinental cultural exchanges occurred in the east section of the Silk Road around 4000 BP, prompting obvious changes of human diet and subsistence strategy in the west region (Hexi Corridor and Hehuang region) during the early Bronze Age (about 4000-3500 BP). However, the character and spatial pattern of the ancient’s diet in different regions of the east section of the Silk Road in the early Bronze Age is not clear. It is because there are few studies on the system analysis of archaeological plant and animal remains, and stable isotopic analysis of plant and animal remains in the west region of the study area in the early Bronze Age. Moreover, it is risky to interpret human collagen nitrogen isotope in the study region. Because we do not have the nitrogen baseline from the plant and/or animal remains to interpret human collagen nitrogen isotope in the east section of the Silk Road during the early Bronze Age. ..Therefore, we are proposed to choose the region with different precipitation (<200mm, 200-400mm, 400-800mm) in the east section of the Silk Road to study the above questions. We will select the early Bronze Age archaeological remains (human, animal and plant remain) and modern plant seeds through the filed investigation and excavation in the east section of the Silk Road. Then we will carry out the analysis of archaeological plant and animal remains. Subsequently, charred plant remains, animal and human bone were sampled for AMS14C dating and stable isotopic analysis. Finally, we will study 1) human diet and its spatial pattern and the influencing factors in the east section of the Silk Road during the early Bronze Age; 2) the spatial pattern and influencing factors of stable nitrogen isotope baseline through the stable isotopic analysis of plant and animal remains and modern plant seeds. The study could advance the interpretation of human diets in arid and semi-arid regions. Moreover, it is important to study the human strategy and its influencing factors in different survival environment.

欧亚大陆东西方文化交流历史及其影响是国际学术界关注的前沿科学问题。近期研究显示丝绸之路东段（西安至敦煌）跨大陆文化互动出现在4000BP左右，促使该地区西部青铜时代早期（约4000-3500BP）人类生业模式和食谱发生明显转变，且呈现空间差异。然而，该时期丝绸之路东段不同区域先民食谱的空间模式尚不清晰，主要受限于该区东部稳定同位素和动植物遗存分析工作的欠缺，以及因不同区域同位素基准缺失导致氮同位素解译存在风险。针对上述问题，拟选择丝绸之路东段不同降水梯度区域采集现代植物样品和关键考古样品，利用碳氮稳定同位素分析和动植物遗存鉴定，结合已有研究结果，揭示青铜时代早期研究区人类食谱及空间模式；通过现代植物和动植物遗存稳定碳氮同位素分析研究同位素基准的空间特征及影响因素。上述工作对推进研究区古食谱的同位素解译研究，认识技术多样化背景下不同生存环境人群的适应策略具有重要学术价值。

欧亚大陆东西方文化交流对欧亚大陆青铜社会影响显著。研究显示丝绸之路东段（西安至敦煌）跨大陆文化互动出现在4000 a BP左右，但是丝绸之路东段不同区域先民食谱的空间模式尚不清晰，主要受限于该区东部稳定同位素和动植物遗存分析工作较少，以及因不同区域同位素基准缺失导致氮同位素解译存在风险。针对上述问题，我们设计并开展了本研究。.对丝绸之路东段及其毗邻地区进行野外考察，并参与6个遗址的发掘工作。采集鉴定了438份动物和187份植物遗存样品，分析测试了61个碳十四测年数据、700个人和动物遗存的碳氮稳定同位素数据，以及142个现代植物和275个的史前植物遗存的碳氮同位素数据，完善了该地区4000-3000 a BP生存策略数据集。.发现，甘青地区牧业活动最早出现在约4000 a BP。4000 a BP之前，甘青地区以开采野生动物资源为主，饲养猪狗为辅。约4000 a BP之后，低海拔地区转变为放牧牛羊。高海拔地区，以开发野生动物资源为主，牧业为辅。.基于不同降水梯度区域的现代植物和史前植物遗存的氮同位素分析，干旱区的氮同位素值显著高于半干旱区和湿润区。4000-3000 a BP干旱地区的野生食草动物δ15N值更高，比半干旱地区高约3.3‰，比湿润区高约1.3‰。.基于本项目新增数据和已发表数据，综合分析发现，青铜时代丝绸之路东段不同地区的人群食谱出现非同步转变。6000-4000 a BP，先民主要食用C4食物，生存策略主要是种植粟黍，辅以狩猎和饲养猪狗。跨大陆文化交流强化之后（4000-2200 a BP），小麦、大麦和牛羊等传入中国并广泛利用，丝绸之路东段人群生业模式空间差异显著。4000-3000 a BP，小麦、大麦和牛羊成为河西走廊先民重要的生产资料；青藏高原东北部地区人群主要种植大麦和牧羊；渭河上游先民依然种植粟黍和养猪，但也开始饲喂牛羊。生存策略非同步转变主要与外来作物和家畜本身的生理特征、自然环境，以及与气候和人口变化相关的生存压力密切相关。.上述工作对推进古食谱的同位素解译研究，对探讨史前人群生存策略、社会发展和环境变化之间的相互作用关系有重要的学术价值。