新疆艾比湖东南缘K3孔晚新生代环境演化

新疆准格尔盆地艾比湖K3孔孔深500.8 m，岩心采取率80.4%。依据光释光(OSL)测年、磁性地层学、磁化率、微体古生物(介形类和有孔虫)、孢粉学和岩相学研究，确定了K3孔晚新生代以来的环境演化过程：该孔钻遇地层属于约4.2 Ma以来沉积，在约3.6～4.2 Ma时期此地是湖泊环境；大约自3.6 Ma以来，伴随着青藏高原快速隆升发生的哈密运动，该区沉积环境由半深湖和浅湖演变为滨湖和水下三角洲，研究区干旱化状况加剧；在约2.6～3.0 Ma的上新世末期，形成盆地边缘和冲积扇体系；2.6 Ma前后，在西域运动-盐水沟运动影响下，研究区是曲流河体系发育期；自“中更新革命”约0.8 Ma以来，全区干旱化状况与现代相近。4.2 Ma以来不连续的孢粉图示和介形类的分布，也显示了沉积动力和水体的复杂变化；构造-气候旋回控制了该地晚新生代环境演化。

Environmental Evolution at the Drilling Hole K3 in the East-south Margin of Ebinur Lake, Xinjiang in Late Cenozoic

The 500.8 meters depth drilling hole K3 with a core recovery efficiency of 80.4% is located at the east-south margin of Ebinur Lake in Zhunger Basin, Xinjiang. Based on the study of OSL dating, palaeomagnetism, susceptibility, micropaleontology (ostracoda and foraminifera), palynology and lithostratigraphy in the borehole, it is determined that the drilled sequences belong to the deposits since cir. 4.2 Ma,there was a lake environment during 3.6-4.2 Ma ,and since cir. 3.6 Ma the sedimentary environment changed from hemi-deep or shallow lake to littoral lake or subaqueous delta accompanying with the Hami Movement as a result of the quickly uplifting of Qinghai-Tibet Plateau, the aridification situation was also aggravating in the study area; during Late Pliocene (cir. 2.6-3.0 Ma) there was a basin margin and fluvial fan sedimentary system; at cir. 2.6 Ma under the influence of the Xiyu Movement and Yanshuigou Movement, the meandering stream system was developed in the study area. Since the Middle Pleistocene Revolution i.e.cir. 0.8 Ma, the aridification situation was similar to that of modern times. The uncontinuous spore-pollen diagram and ostracoda distribution show a complicated development of sedimentary dynamics and water bodies since 4.2 Ma. The environmental change in the study area had been controlled by the tecto-climatic cycles.