Spatial Distribution Characteristics and Genetic Mechanism of the Metasilicate-Rich Groundwater in Ji’nan Rock Mass Area, Shandong Province, China

Abstract

Metasilicate-rich groundwater could meet the high demand of the international community for high-quality water. In order to comprehensively analyze the genetic mechanism of metasilicate-rich groundwater, and help human communities effectively exploit and utilize high-quality water resources, taking the Ji’nan rock mass area as an example, this study carried out systematic research on the spatial distribution and genetic mechanism of the metasilicate-rich groundwater Based on the regional hydrogeological conditions, the influencing factors on the spatial distribution characteristics of the metasilicate-rich groundwater in the study area were systematically sorted out by means of petrogeochemistry, hydrochemistry, and chemical weathering index analysis, and the accumulation mechanism of the metasilicate-rich groundwater was discussed from the perspective of water-rock interaction. The results show that: (1) On the northwest side and part of the northeast side of Ji’nan rock mass, the metasilicate content of the groundwater samples exceeded 25 mg/L; the metasilicate content on the south, west, and east sides were relatively low; (2) Ji’nan rock mass is mainly composed of gabbro easily weathered, with high SiO2 content and high weathering degree showing obvious characteristics of desilication. FeS2 developing along the contact zones between the rock mass and surrounding rocks was easily oxidized to form H2SO4, which enhanced the solubility of silicate minerals in the groundwater. Ji’nan rock mass was located in the low-lying position of the monocline structure, which presented better water conservation and recharges conditions. The above factors resulted in the metasilicate-rich groundwater accumulating in the area of Ji’nan rock mass and showed different spatial distribution characteristics.