沉积物粘土混浊水电导率与pH值相关性研究——以渤海湾西岸平原XZ、MD钻孔为例

THE CORRELATION BETWEEN ELECTRIC CONDUCTIVITY AND pH OF THE STICS-WATER： A CASE STUDY OF CORES XZ AND MD ON THE PLAIN OF WEST BOHAI BAY

对渤海湾西岸平原XZ、kiD钻孔样品的粘土混浊水电导率（以下简称EC）和pH测定值进行相关分析，结果显示EC与pH都呈高度负相关，两孔的相关系数分别为-0．830（P〈0．01）和-0．765（P〈0．01）。整体上EC与pH呈反比特征。进一步根据EC测定值将两钻孔沉积物分为海相、海陆过渡相和陆相分带，并对各分带中的EC和pH作相关性分析，结果表明除XZ孔海相沉积带（I带）相关性偏低（r=0．089，P〉0．05）外，其他各沉积带均显示较明显的负相关。但负相关性也有所不同，XZ孔海陆过渡相沉积带（Ⅱ带，r=-0．740，P〈0．01）负相关性最为明显；kiD孔海陆过渡相沉积带（I带，r=-0．434，P〈O．01）、XZ孔陆相沉积带（Ⅲ带，r=-0．403，P〈0．05）和MD孔陆相沉积带（Ⅱ带，r=-0．482，P〈0．05）也有较明显的负相关性。这表明沉积物EC与pH相关程度的差异，亦可在一定程度上反映出其沉积环境的不同。

The electric conductivity of stirred clayey sediments into water （STICS-water） is a substitute index which has been newly used in identifying sedimentary layers in the plain of west Bohai Bay, which is an ideal region for the study of Quaternary sediments. Some papers discussed that pH was negatively correlated with EC, therefore, pH could be regarded as an auxiliary index. However, further research in this topic is still under discussion, especially the detailed researches on the correlation between EC and pH in different sedimentary facies. Based on the correlation between EC and pH of sediments of core XZ （38°56′30.3＂N, 117°28′05. I＂E） and core MD （38°59′16. I＂N, 117°15＇37.4＂E） on the plain of west Bohai Bay, we discussed that EC was significantly negatively correlated with pH for core sediments, with the correlation coefficients of -0. 830 （P〈 0.01 ） and -0. 765 （P〈0.01） , revealing that EC was low and pH was high for oceanic sediments, while EC was high and pH was low for continental sediments. However, variations occurred when discussing the relationship between EC and pH on different sedimentary facies. We divided the sediments of two cores into several bands mainly depending on the determination results of EC. The dividing standard was put forward by Uchizono Tatuo, regarding sediments with EC below 0.6mS/cm as continental facies, 0.6- 1.5mS/cm as marine-continental transitional facies, higher than 1.5mS/cm as marine facies. The variation trend of EC and some symbolic organisms were also taken into account as auxiliary indexs. When it came to the result, the correlation coefficients were high in the following facies： the continental facies of core XZ （ band 11I, r = -0. 403, P〈0.05） , the marine-continental transitional facies of core XZ （ band 11, r=-0. 740, P〈0.01） , the continental facies of core MD （ band 11, r=-0. 482, P〈0.05）, and the marine-continental transitional facies of core MD （band I, r =-0. 434, P〈0.01 ） , all of which were negative correlation. While the correlation coefficient of the marine facies of core XZ （ band I ） was very low （r = 0. 089, P〉0.05）. The results show that the differences of correlation between EC and pH of sediments is able to partly reflect the variational sedimentary environments.