衡水地区咸水层沉积物粒度及氘氧同位素的古气候指示  

Paleoclimate Instruction of Sediment Grain Size and Deuterium-Oxygen Isotope in Saline Stratum of Hengshui

作　　者：牛宏[1] 梁杏[1,2] 李静[1] 马斌[1] 葛勤[1] 

机构地区：[1]中国地质大学环境学院,湖北武汉430074 [2]中国地质大学湿地演化与生态恢复湖北省重点实验室,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2016年第3期499-507,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家重点基础研究发展计划"973"项目(No.2010CB428802);国家自然科学基金(Nos.41272258;U1403282)

摘　　要：衡水地区的咸水层特征一直备受关注.为了探讨咸水层分布区的沉积环境与咸水形成期的古气候特征,利用钻孔(深度130m)采集了衡水地区咸水层沉积物,进行了沉积物粒度和粘性土孔隙水氘氧同位素测试.沉积物粒度标准偏差显示,剖面上由深至浅,沉积时期水动力呈由弱到强再到弱的变化趋势,其中水动力强段为90~65m,为厚层砂砾层.孔隙水TDS和δ^(18)O特征显示在6m以上受到大气降水和人类活动的影响,并且主要是以淡水灌溉影响为主.剖面上粘性土孔隙水的δ^(18)O在130~90m平均值为-11.5‰,65~29m平均值为-12.1‰,23~0m为-10.6‰,而下部淡水含水层地下水δ^(18)O为-9.8‰,上部咸水含水层地下水δ^(18)O为-8.2‰,粘性土孔隙水δ^(18)O明显偏负于含水层的地下水,反映保存记录了古气候信息.130~90m,δ^(18)O先增大后减小反映温度先升高后降低;65~29m,δ^(18)O反映温度偏低的气候特征;23~0m,δ^(18)O相对比较稳定,总体偏正,反映了全新世为一个相对较为稳定但较高的温度.The characteristics of saline stratum in Hengshui have always been concerned. In order to discuss the paleoenviron- ment and the paleoclimate in Hengshui area, grain size and pore water stable isotope （δD, δ18O） of clay collected from Heng- shui saline stratum（thickness of 130 m） by drilling were analyzed. The standard deviation of sediment grain size shows that the hydrodynamic strength changed from weak to strong and then to weak, there is a deep gravel layer in 90-65 m, which reflects a strong hydrodynamic strength and a humid clime. The TDS and δ18O reflect the affect of atmospheric precipitation and human irrigation above 6 m, specially for the human irrigation. The mean value of δ18O at depth of 130-90 m is -11.5‰, and it is -12. 1‰ and -10. 6%0 at depth of 65-29 m and 23-0 m. The 8180 of aquifer at 90-65 m is -9.8‰, and -8. 2%0 of 29- 23 m. The δ18O of clay pore water is negative compared with the aquifer groundwater, reflecting that the clay pore water saves paleoenvironment information. The δ18O at depth of 65-29 m firstly increases and than decreases reflecting the temperature firstly increases and than decreases; the δ18O at depth of 65-29 m reflects a low temperature; the δ18O at depth of 23-0 m is relatively stable, but is positive overall, indicating a warm climate in Holocene.

关 键 词：衡水 沉积物粒度 粘性土孔隙水 氘氧同位素 古气候 

分 类 号：P532[天文地球—古生物学与地层学]