【作者】 申建梅；

【导师】 张光辉； 王路光；

【作者基本信息】 中国地质科学院 ， 地质工程， 2008， 博士

【摘要】 酒泉东盆地盐池地区是甘肃省最大的芒硝、原盐富集地和酒泉东盆地地下水主要分布区。因此,研究盐池地区地下水咸化成因及规律,不仅对于查明干旱区地下水的水盐迁移、富集和成矿具有重要意义,而且对于西北内陆干旱区地下水合理开发利用和盐矿保护也具有重要的指导意义。本项研究的目标是揭示酒泉东盆地盐池地区地下水咸化成因和演变特征,为地下水可持续利用和盐矿合理开发提供科学依据。为此,以酒泉东盆地为研究区,盐池地区为重点研究区,侧重开展下列研究内容:(1)水循环系统中不同水体水化学和环境同位素特征;(2)地下水咸化的水盐变化规律及来源;(3)地下水咸化过程中古气候特征。本文以水循环系统理论为指导,以环境同位素和水化学信息作为研究基础,综合应用水文地质学、水文地球化学、同位素水文学以及相关的数学理论,采用定性判断和定量分析相结合的方法,全面调查研究区的自然背景条件,综合研究了不同水体的水化学和同位素特征,通过同位素和水化学信息的示踪功能和放射性测年技术,阐明地下水咸化演变规律及来源。在上述研究基础上,结合孢粉和氯同位素的古气候指标,探讨了1.6万年以来研究区古气候及环境变化。通过上述研究,得出如下新认识和进展:1.地下水咸化发生在地史演进中并与现代水循环有联系大量地下水化学和同位素信息表明,酒泉东盆地盐池地区地下水咸化发生在末次冰期以来地史演进中,与现代水循环有密切的联系。地下水咸化的水盐来源主要有:①大气降水入渗补给;②祁连山山区河水渗漏补给;③深层地下水顶托越流补给。2.阐明地下水咸化成因盐池是酒泉尔盆地流域尺度水循环过程中水盐滞留聚集区,具有充足的水盐补给条件、汇水积盐的地质和地貌条件(盐池凹地及北山阻隔)、有利水盐汇聚的水循环条件(径流停滞、垂直蒸发)和蒸水浓盐的气候条件(长期干旱,蒸发强烈)。这些条件都有利于地下水的盐分积聚。3.揭示了1.6万年以来古气候演变特征1.6万年以来盐池地区经历了冷干-暖湿-干旱的演变过程,总的变化趋势是由草原景观向干旱方向演变,湖泊趋于干涸,湖水咸化,木本植物和蕨类植物基本消失,耐旱植被逐渐为主,蒿、藜为主的干旱荒漠草原已成为现代景观,地下水咸化成为现状。4.提出地下水资源合理利用方案根据盐池地区地下水的水盐迁移和分布规律,将地下水资源利用分为三个区:山前地下水涵养区、中部绿洲地下水开采区、北部盐矿地下水保护控采区。开采-恢复相结合的地下水利用方案,即保证盐矿矿产产量,又有利于水资源合理利用。更多还原

【Abstract】 Yanchi area of Jiuquan East Basin in Gansu Province is the largest enrichment area in mirabilite and raw salt, it is also the main groundwater distributed area in Jiuquan East Basin. Therefore, it is very useful to make research on the cause and law of groundwater salinization. On one hand, it is helpful to make clear of water and salt migration, enrichment and mineralization of salt in arid area groundwater system. On the other hand, it is significant to reasonable development and utilization of salt mines in northwest inland.In order to provide logical reasons for sustainable utilization of groundwater and rational exploration of salt mines, the goal of this study is to reveal the cause and evolution characteristics of groundwater salinization in Yanchi area of Jiuquan East Basin. Therefore, Jiuquan East Basin as the study area and YanChi as the main study area, the study focused on the following four main parts: (1) water chemistry and environmental isotope characteristics of different water body in water cycle systems; (2) changing law and source of groundwater salinization; (3) paleoclimate significance during the process of groundwater salinization.Based on water cycle system theory , environmental isotope and water chemistry information, this study comprehensively used hydrogeology, hydro-geochemistry, isotope hydrology, and related mathematical theory, it also combined qualitative estimation and quantitative analysis. Using these methods, this study maked clear of natural background condition of the study area, and analyzed water chemistry and environmental isotope characteristics of different water bodies by the technologies of tracing function and radioactive dating techniques of isotope and water chemistry information, and illustrated evolution characteristics and source of groundwater salinization. Based on the above analyses and combining paleoclimate index of pollen and chlorine isotope, this dissertation discussed paleoclimate and environment change in the last 16 thousand years. Finally, the peper gained following understanding.1. Relationship between groundwater salinization evolution history and modern water cycleA lot of groundwater chemistry and isotopic information showed that groundwater salinization of Yanchi area of Jiuquan East Basin happened in aBP history, and there is a close relationship between groundwater salinization and modern water cycle. Major source of groundwater salinization is from precipitation infiltration recharge, Qilian Mountain area river leakage, and deep groundwater leaky.2. Cause of groundwater salinizationYanchi is the water and salt enrichment area in water cycle system of Jiuquan East Basin, because there are several advantages, such as adequate supplies of water and salt, geological and geomorphological condition of gathering water and salt (Yanchi valley and Beishan obstruct), suitable water cycle condition of accumulating water and salt (stagnant runoff and vertical evaporation), and good climate condition of concentrating salt (perennial drought and strong evaporation intensity). All the conditions are conductive to groundwater salinization.3. Paleoclimate evolution characteristics in the last 1.6 million yearsThere was a climate evolution process from cold-drying to wetness to drying in Yanchi area in the last 1.6 million years. During the process, grassland was becoming drought, lakes were drying, water salinization was starting, and woody plants and pteridophyte were almost disappeared. Instead, drought-resistant plants were becoming more, so fleabane and goosefoot were becoming modern landscape and groundwater salinization was finally formed.4. Project of logical utilization of groundwaterAccording to water and salt migration and distributing characteristics, this study divided the whole study area into three groundwater utilization parts. They were piedmont groundwater conservation area, middle oasis exploration area and northern salt mines groundwater protected-mining area. Considering both exploration and recovering, the utilization programs of groundwater can not only ensure salt mines mineral production, but also guarantee rational utilization of water resources.更多还原