青藏高原东北缘全新世人类活动与环境变化——以青海湖江西沟2号遗迹为例

Human activities and environmental change in Holocene in the northeastern margin of Qinghai-Tibet Plateau: A case study of JXG2 relic site in Qinghai Lake

青海湖江西沟遗迹是青藏高原东北缘一处有连续地层的重要细石器文化遗存，对其人类活动指标（石器、动物碎骨、陶片等）与环境指标（磁化率、色度、孢粉及集成结果）对比分析表明：细石器文化与环境变化关系密切，在全新世JXG2细石器狩猎者一直生活在以蒿为主的草原环境。在9kaBP以前的早全新世，环境状况不断好转，人类已经在湖区活动，并逐渐增强；9kaBP后最佳的水热组合，较高的草原覆盖，为细石器狩猎者提供充足的食物来源，推动文化进入鼎盛期；6kaBP后随着环境干冷化，细石器文化也开始衰弱。孢粉分析发现9～6kaBP高的禾本科含量及种类丰富的杂草花粉，与人类活动有关；尤其是禾本科含量在6．7～4kaBP保持较高水平，此时段恰是陶片开始出现并普遍使用的时期，推测与JXG2先民尝试种植农作物有关。高原东北缘在6kaBP之前为细石器文化，6kaBP之后高原史前文化开始发生分化，细石器狩猎者活跃在海拔较高的高原上，农业种植者占据了较低的河谷地带，在二者交接地带，形成了兼具细石器文化与农业种植文化特征土著新石器文化。

Jiangxigou archaeological site is located in northeastern margin of the Qinghai-Tibet Plateau （QTP）. This section is an important Microlith relic site with consecutive strata. Here we present an integrated study on multi-proxy including human activities index （stone, animal bones and pottery shreds） and environmental index （magnetic susceptibility, color and pollen） of this section. The results show that the occurrence of Microlith has a close relationship with environmental change. In the Holocene, Microlith hunters lived in an Artemisia dominant environment. Before 9 ka BP, human activities initiated to appear on the QTP due to the increasing improvement of the early Holocene climate. After 9 ka BP, steppe vegetation was well developed under the optimal climate of this time, which supplied abundant foods for hunters, and thus promoting Microlith culture into the prosperous period. Since 6 ka BP, as the deterioration of the climate, the Microlith culture began to decay. Pollen analysis indicates that relatively high content of Poaceae and the attendent weedy plants might relate to the human activities. The proportion of Poaceae reached its highest level during 6.7-4 ka BP, which was corresponding to the stage when pottery shreds were widely used. We suggest that these facts would relate to the crop cultivation during this time. The occurrence of pottery shreds was probably associated with the farming activities of ancient people. Based on these records, we conclude that the culture in the northeastern margin of the QTP was Microlith culture before 6 ka BP and has changed since then. After 6 ka BP, the Microlith hunters lived at higher elevations of the plateau while the farmers occupied the valley regions at relatively low altitudes.