深埋低渗透粘性土中的孔隙水运移缓慢，滞留时间长，是极具价值的古气候记录档案。但是沉积盆地中，粘性土层往往与砂层交互沉积，含水层地下水的交替更新引起其与相邻粘性土孔隙水间较大的化学浓度梯度，导致含水层与粘性土层间扩散交换，使粘性土孔隙水记录的古沉积环境信息失真。因此，在解读粘性土孔隙水古气候记录档案时，需要查明扩散作用的影响程度。本课题以渤海湾西岸第一与第二含水层间的厚层粘性土为例，通过钻孔采集连续的粘性土柱，获取粘性土孔隙水化学和同位素的垂向分布特征；进行原状土孔隙水静态扩散实验，获得粘性土孔隙水化学组分（Cl-）有效扩散系数和粘性土有效孔隙度，建立粘性土垂向一维溶质运移扩散模型，揭示厚层粘性土中孔隙水化学组分的扩散运移过程，从而探讨扩散作用对孔隙水古气候记录信息的影响程度。为古气候研究、地下水资源评价、地下水环境的安全保护提供重要的科学依据，同时也将拓宽低渗透介质水文地质学的研究内容。

Clay-rich aquitard pore water is valuable paleo-climate record file, due to its slow transport and long resident time in low permeable deep buried clay formation. However, in the sedimentary basins, clay and sand layers are always alternatively deposited. Regeneration of the groundwater in aquifers (sand layers) would result an extensive solutes concentration gradient with the adjacent clayey pore water. The gradient causing the diffusion between aquifer groundwater and clay pore water would complicate the paleo-climate information record of clay pore water. Therefore, in the application of aquitard pore water to reflect paleo-climate, we need find out the diffusion effect on the pore water. In this study, we will collect a series of undisturbed clayey samples, located between the first and the second aquifer in western Bohai Bay. Extract pore water from the clay core samples, and get the vertical profile of chemical components and isotopes of aquitard pore water. Then using the undisturbed clayey samples to conduct pore water static diffusion experiments and obtain the effective diffusion coefficient of pore water Cl- and clay effective porosity. Through the one-dimension diffusion modeling of pore water solute in clay, we will find out the diffusion process of pore water chemical components in thick clay formation, and evaluate the diffusion effect on the pore water paleo-cliamte information. This study may supply scientific instructions to paleo-climate, groundwater resource and groundwater environment protection, and also enrich the hydrogeology contents on low permeable medium.