珠江三角洲区域地下咸水的起源与演化

地下咸水是一种宝贵资源。珠江三角洲地下咸水广泛分布,但研究程度不高。基于国家地质调查项目获得的第一手资料,从沉积学、水文地球化学角度,对珠江三角洲区域性地下咸水的起源与演化进行了研究,结果表明:地下咸水起源于古海水,与中全新世早期退积作用过程密切相关;沉积压实作用使封存于弱透水层中的海水越流至第四系底部的承压含水层;部分地段地下咸水形成过程中,可能受到了溶滤水的影响,矿物溶解与阳离子交换吸附等作用可能造成地下咸水盐分的富集。

ORIGIN AND EVOLUTION OF REGIONAL SALINE GROUNDWATER IN THE PEARL RIVER DELTA

As a kind of valuable resource, saline groundwater is widely distributed in the Pearl River delta, which is less studied. Based on primary data obtained in the national geological survey program, we implement a targeted study on origin and evolution of the saline using sedimentology and hydrogeochemistry. We find that the saline groundwater is originated from paleo-seawater and highly related to retrogradation process in the early period of middle Holocene. Seawater originally included in less permeable strata leaks to underlying confined aquifer by compaction. Saline groundwater is possibly influenced by lixiviation water in formation process. Mineral dissolution and ion exchange may contribute to the salinity enrichment.