辽西早白垩世义县组大康堡层纹泥的古环境意义

辽西地区义县组湖泊沉积层中产出著名的“热河生物群”化石，对于此时期古环境的研究一直是诸多学者关注的焦点.本文对大康堡层湖相纹泥展开研究，重建此时期古环境.通过野外及室内对纹泥组成、类型、厚度等方面的观测，对此时期古气候有了新的认识.纹泥厚度特征变化表明沉积期降水量和沉积速率逐渐减小，统计洪水沉积间纹层数量可指示沉积期洪水事件的频率和规模.结合近现代纹泥形成和保存条件，可知该地区沉积期湖泊水体较深，湖水分层，存在一个缺氧环境，具有较小的表面积/深度比，湖盆形态适合，未受到风的侵扰.

Palaeoenvironment Significance of Dakangpu Layer Varve in Yixian Formation in Lower Cretaceous of Western Liaoning

Lake sediments of Yixian formation in the western part of Liaoning Province output the famouse “Jehol Biota” fossils， it is a hot issue for the study of the palaeoenvironment at this period. This paper focuses on the varves in Dakangpu Layer and reconstruct the lacustrine palaeoenvironment. New understanding of the palaeoclimate in this period is obtained through carefully observing the composition， type， thickness of varve in the field and laboratory. The change of varve thickness indicates the decrease in the precipitation and deposition rates in Dakangpu stage. The thickness of the varve between the flood deposits can be used to interpret the frequency and scale of the flood events. Combined with the deposition and preserved environmental conditions of modern varves， during the deposition period of Dakangpu Layer， there is a specific depositional environment and a deep， stratified， oxygen-restricted， low surface area/depth ratio lake.