共查询到20条相似文献，搜索用时 521 毫秒
1.
Laurence R. Bentley Masaki Hayashi Elena P. Zimmerman Chris Holmden Lynn I. Kelley 《Hydrogeology Journal》2016,24(4):877-892
Hypersaline lakes occur in hydrologically closed basins due to evaporitic enrichment of dissolved salts transported to the lakes by surface water and groundwater. At the hypersaline Lydden Lake in Saskatchewan, Canada, groundwater/lake-water interaction is strongly influenced by the geological heterogeneity of glacial deposits, whereby a highly permeable glaciofluvial sand/gravel deposit is underlain by glaciolacustrine deposits consisting of dense clay interspersed with silt/sand lenses. Pressure head distribution in a near shore area indicates a bi-directional flow system. It consists of topographically driven flow of fresh groundwater towards the lake in the sand/gravel aquifer and density-driven, landward flow of saline groundwater in the underlying glaciolacustrine deposits. Electrical resistivity tomography, and chemical and isotopic composition of groundwater clearly show the landward intrusion of saline water in the heterogeneous unit. The feasibility of bi-directional flow and transport is supported by numerical simulations of density-coupled groundwater flow and transport. The results suggest that the geologically controlled groundwater exchange processes have substantial influences on both inputs and outputs of dissolved minerals in hypersaline lakes in closed basins. 相似文献
2.
The Tyrell catchment lies on the western margin of the Riverine Province in the south-central Murray Basin, one of Australia’s most important groundwater resources. Groundwater from the shallow, unconfined Pliocene Sands aquifer and the underlying Renmark Group aquifer is saline (total dissolved solids up to 150,000 mg/L) and is Na-Cl-Mg type. There is no systematic change in salinity along hydraulic gradients implying that the aquifers are hydraulically connected and mixing during vertical flow is important. Stable isotopes (18O+2H) and Cl/Br ratios indicate that groundwater is entirely of meteoric origin and salts in this system have largely been derived by evapotranspiration of rainfall with only minor halite dissolution, rock weathering (mainly feldspar dissolution), and ion exchange between Na and Mg on clays. Similarity in chemistry of all groundwater in the catchment implies relative consistency in processes over time, independent of any climatic variation. Groundwater in both the Pliocene Sands and Renmark Group aquifers yield ages of up to 25 ka. The Tyrrell Catchment is arid to semi-arid and has low topography. This has resulted in relatively low recharge rates and hydraulic gradients that have resulted in long groundwater residence times. 相似文献
3.
Datong Basin is one of the Cenozoic faulted basins in Northern China’s Shanxi province, where groundwater is the major source of water supply. The results of hydrochemical investigation show that along the groundwater flow path, from the margins to the lower-lying central parts of the basin, groundwater generally shows increases in concentrations of TDS, HCO3 ?, SO4 2?, Cl?, Na+ and Mg2+ (except for Ca2+ content). Along the basin margin, groundwater is dominantly of Ca–HCO3 type; however, in the central parts of the basin it becomes more saline with Na–HCO3-dominant or mixed-ion type. The medium-deep groundwater has chemical compositions similar to those of shallow groundwater, except for the local area affected by human activity. From the mountain front to the basin area, shallow groundwater concentrations of major ions increase and are commonly higher than those in medium-deep aquifers, due to intense evapotranspiration and anthropogenic contamination. Hydrolysis of aluminosilicate and silicate minerals, cation exchange and evaporation are prevailing geochemical processes occurring in the aquifers at Datong Basin. The isotopic compositions indicate that meteoric water is the main source of groundwater recharge. Evaporation is the major way of discharge of shallow groundwater. The groundwater in medium-deep aquifers may be related to regional recharges of rainwater by infiltrating along the mountain front faults, and of groundwater permeating laterally from bedrocks of the mountain range. However, in areas of groundwater depression cones, groundwater in the deep confined aquifers may be recharged by groundwater from the upper unconfined aquifer through aquitards. 相似文献
4.
The Okavango Delta of semi-arid northern Botswana is a large alluvial fan (22,000 km2) covered by permanent and seasonal swamps from which 96% of the annual discharge is lost by evapotranspiration. Many small islands (1ha) within the permanent swamps are the sites of accumulation of sodium carbonate salts and many contain saline pans. The associated alkaline soils are toxic to vegetation. An understanding of the processes involved in alkalinization could be of potential benefit to long-term conservation planning in this unique ecosystem. The relation between soil chemistry and mineralogy, and swamp and groundwater chemistry were investigated on an island in the swamps. The study revealed that the water table beneath the island is depressed and swamp water enters the groundwater regime of the island from the margins and below, and flows toward the centre. The water becomes progressively more saline, initially owing to transpiration by trees and ultimately by evaporation in the central parts of the island. As a result of increasing salinity, amorphous SiO2 and magnesium calcite precipitate in the soils beneath the marginal zone of the island, raising the land surface, while the more soluble alkali carbonates are concentrated in the centre of the island as surface crusts and brine ponds. Leaching of these salts into the soil during the rainy season and gravity-driven flow of saline brines in the dry season causes the downward movement of Al and Fe in the central zone of the island. K-feldspar and possibly amorphous allophane develop in the deeper soils under the central zone of the island. 相似文献
5.
The Ethiopian Rift (a major portion of the Great East African Rift) is characterized by a narrow elongated depression bounded by highlands from both sides. This topographic configuration leads to a monsoon redistribution which resulted in an arid rift floor and humid high rainfall highlands. The rifting and associated volcanism also caused a thinning of the crust and facilitates influx of CO2 and other mantle gases as diffuse sources or along faults from deeper sources. Groundwaters in the rift floor are usually of high mineral content (high F, U, As and salinity) while those on the plateau are of low mineral content. Among many factors, groundwater availability and quality in the rift floor aquifers is the function of their connection to the aquifers in the high rainfall plateau and the residence time of groundwater prior to reaching the rift floor. This entails the need for addressing one basic hydrologic question in such a setting: at what depth and rate does recharge from the high rainfall highland reach the lowland rift aquifers? This study uses spatial variations in trace elements and relates them to 14C variations, thereby investigating the suitability of using trace elements as proxies for residence time estimation of groundwaters of relatively short (1,000–2,000 years) residence time. This work also investigates the behavior of trace element trends along the groundwater flow path in a rifted setting and compares them with such trends in sedimentary aquifers elsewhere. The comparison shows a clear difference in behavior of trace elements along the groundwater flow path when compared with such variations in big sedimentary basins with no prominent rifting and volcanism, suggesting the need of calibrating the relation between trace elements and any direct residence time indicators. An integrated use of major elements, trace elements, and environmental isotopes reveals that the main recharge of the aquifers originates from mountain blocks and that recharge takes place via fractures with no evidence of evaporation prior to recharge. Redox processes appear to play a limited role in trace element geochemistry of groundwaters in the region. Progressive trends in trace element composition along the groundwater flow path suggest continuous groundwater flow from the plateau. 相似文献
6.
内蒙古五原县塔尔湖地区发育一系列湖泊,与当地干旱气候形成鲜明的对比,湖泊成因机制对河套地区第四纪水文地质、气候环境研究具有重要意义。对色尔腾山山前—塔尔湖湖泊—黄河沿线不同水体样品进行水化学测试后,利用Gibbs模型投影显示湖泊采样点主要落在蒸发-浓缩端元和岩石风化端元的过渡带,而远离大气降水作用带,地下水更靠近岩石风化端元,说明湖泊接受地下水补给,蒸发强烈;Piper三线图显示山前泉水以HCO3—Ca型为主,河套平原地下水以HCO3—Na、Cl—Na型为主,黄河水为HCO3—Na型,湖泊以Cl—Na型为主,说明塔尔湖地区地下水与湖泊存在水力联系,HCO3—Na型地下水经过蒸发浓缩作用转变成了盐度更高的Cl—Na型湖泊,导致盐分的聚集;地下水可溶性固体总量(TDS)自北向南由262 mg/l快速增加至2 296 mg/l,而湖泊TDS先升后降,最后小于地下水TDS,最大值在塔尔湖地区北部,为1 213 mg/l,说明湖泊还受现代黄河补给,地下水TDS变化满足山前—盆地的水文地质模型。塔尔湖地区的湖泊既可以发育于古河床亚相也可以发育于堤坝亚相,且湖泊呈零星分布,与古河道形成的牛轭湖特征不吻合,从而基本排除湖泊为古黄河残留的可能;潜水面之上的河流相沉积物由于风蚀作用被切穿,导致地下水出露,补给湖泊,从而推断塔尔湖地区湖泊主要为风蚀湖。 相似文献
7.
Assessment of soil salinization based on a low-cost method and its influencing factors in a semi-arid agricultural area,northwest China 总被引：13，自引：9，他引：4
An investigation of soil salinization was carried out in the Nanshantaizi area (Northwest China) with WET Sensor. This device can measure such soil parameters as bulk soil electrical conductivity, water content, and the pore water electrical conductivity that are important for soil salinization assessments. A distribution map of soil salinization was produced, and the factors influencing soil salinization and its processes were discussed in detail. The study shows that moderately salinized to salt soils are mainly observed in the alluvial plain, where groundwater level is high and lateral recharge water contains high salinity. Nanshantaizi is covered by slightly salinized soils. The soil salinization distribution estimated by WET Sensor is generally consistent with the actual levels of salinization. Soil salinity in Nanshantaizi is mostly of natural origin and accumulated salts could leach to deeper soils or aquifers by water percolation during irrigation. Groundwater evaporation, groundwater level depth and quality of recharge water are important factors influencing soil salinization in the alluvial plain. 相似文献
8.
Characterisation of groundwater chemistry in an eastern coastal area of Cuddalore district,Tamil Nadu 总被引：1，自引：0，他引：1
K. Srinivasamoorthy M. Vasanthavigar S. Chidambaram P. Anandhan V. S. Sarma 《Journal of the Geological Society of India》2011,78(6):549-558
The groundwater quality detoriation due to various geochemical processes like saline water intrusion, evaporation and interaction
of groundwater with brines is a serious problem in coastal environments. Understanding the geochemical evolution is important
for sustainable development of water resources. A detailed investigation was carried out to evaluate the geochemical processes
regulating groundwater quality in Cuddalore district of Tamilnadu, India. The area is entirely underlined by sedimentary formations,
which include sandstone, clay, alluvium, and small patches of laterite soils of tertiary and quaternary age. Groundwater samples
were collected from the study area and analyzed for major ions. The electrical conductivity (EC) value ranged from 962 to
11,824 μS/cm, with a mean of 2802 μS/cm. The hydrogeochemical evolution of groundwater in the study area starts from Mg-HCO3 type to Na-Cl type indicating the cation exchange reaction along with seawater intrusion. The Br/Cl ratio indicates the evaporation
source for the ion. The Na/Cl ratios indicate groundwater is probably controlled by water-rock interaction, most likely by
derived from the weathering of calcium-magnesium silicates. The plot of (Ca+Mg) versus HCO3 suggests ions derived from sediment weathering. The plot of Na+K over Cl reflects silicate weathering along with precipitation.
Gibbs plot indicates the dominant control of rock weathering. Factor analysis indicates dominance of salt water intrusion,
cation-exchange and anthropogenic phenomenon in the study. 相似文献
9.
中国是一个多盐湖国家,然而盐湖研究主要集中于分析湖水化学性质、盐类物质来源和盐矿资源开发等,对盐类矿物沉积特征和埋藏成岩改造研究较少,造成从蒸发岩角度去理解古代盐湖盆地的油气富集规律较为困难。在广泛阅读国内外大型盐湖文献的基础上,笔者介绍了盐湖分类方案和蒸发岩中盐类矿物的主要成因类型,并总结了中国陆相含油气盆地中常见的硫酸盐、氯化物、含钠碳酸盐和硼酸盐的沉积—成岩过程及其古环境和古气候意义。同时,尝试利用盐湖沉积最新研究成果去探讨中国含油气盆地蒸发岩研究中存在争议或值得关注的问题,得出: (1)深部热液可为湖泊输送大量元素离子,但要在湖泊环境下富集大量蒸发岩,则(半)干旱气候和蒸发浓缩作用是前提条件;(2)易溶蒸发岩(如石盐)在沉积中心单层厚度大,而在斜坡—边缘区缺失,这是季节性气温变化和温跃层浮动引发“中心聚集效应”的结果;(3)温度可影响蒸发岩中盐类矿物溶解度、晶体结构形态和发育深度,而部分无水盐类矿物在常温常压下却无法结晶,这一现象可用来指示古地温和地层埋藏史;(4)碳酸盐型盐湖中的Na-碳酸盐种类可指示大气CO2浓度和古温度。 相似文献
10.
The problem of soil degradation through alkalinization/salinization in an irrigated area with a semi-arid climate was examined in the inner delta of the Niger River, Mali, by the study of groundwater hydraulics and hydrochemistry in an area recharged by irrigation water. On the basis of data analysis on various scales, it is concluded that the current extent of the surface saline soils is due to a combination of three factors: (1) the existence of ancient saline soils (solonchaks) resulting from the creation of a broad sabkha west of the former course of the Niger River, now called the Fala of Molodo. These saline crusts were gradually deposited during the eastward tilting of the tectonic block that supports the Niger River; (2) the irrigation processes during the recent reflooding of the Fala of Molodo (river diversion in 1950). These used very poorly mineralized surface water but reintroduced into the alluvial groundwater system – generally of a low permeability (K=10–6?m?s–1) – salts derived from the ancient solonchaks; and (3) the redeposition of the dissolved salts on the surface due to the intense evapotranspiration linked to the present Sahelian climate. In this context, only efficient artificial draining of subsurface alluvial groundwater can eliminate most of the highly mineralized flow and thus reduce the current saline deposits. 相似文献
11.
中国是一个多盐湖国家,然而盐湖研究主要集中于分析湖水化学性质、盐类物质来源和盐矿资源开发等,对盐类矿物沉积特征和埋藏成岩改造研究较少,造成从蒸发岩角度去理解古代盐湖盆地的油气富集规律较为困难。在广泛阅读国内外大型盐湖文献的基础上,笔者介绍了盐湖分类方案和蒸发岩中盐类矿物的主要成因类型,并总结了中国陆相含油气盆地中常见的硫酸盐、氯化物、含钠碳酸盐和硼酸盐的沉积—成岩过程及其古环境和古气候意义。同时,尝试利用盐湖沉积最新研究成果去探讨中国含油气盆地蒸发岩研究中存在争议或值得关注的问题,得出: (1)深部热液可为湖泊输送大量元素离子,但要在湖泊环境下富集大量蒸发岩,则(半)干旱气候和蒸发浓缩作用是前提条件;(2)易溶蒸发岩(如石盐)在沉积中心单层厚度大,而在斜坡—边缘区缺失,这是季节性气温变化和温跃层浮动引发“中心聚集效应”的结果;(3)温度可影响蒸发岩中盐类矿物溶解度、晶体结构形态和发育深度,而部分无水盐类矿物在常温常压下却无法结晶,这一现象可用来指示古地温和地层埋藏史;(4)碳酸盐型盐湖中的Na-碳酸盐种类可指示大气CO2浓度和古温度。 相似文献
12.
Groundwater in the Latrobe Valley in the Gippsland Basin of southeast Australia is important for domestic, agricultural and industrial uses. This sedimentary basin contains a number of aquifers that are used for water supply, dewatered for open pit coal mining, and which are potentially influenced by off-shore oil and gas production. Major ion chemistry together with stable and Sr isotope data imply that the main hydrogeochemical processes are evapotranspiration with minor silicate and carbonate weathering; methanogenesis and SO4 reduction in reduced groundwater associated with coal deposits have also occurred. Groundwater has estimated 14C ages of up to 36 ka and is largely 3H free. Carbon-14 ages are irregularly distributed and poorly correlated with depth and distance from the basin margins. The observations that the geochemistry of groundwater in aquifers with different mineralogies are similar and the distribution of 14C ages is irregular implies that the aquifers are hydraulically connected and horizontal as well as vertical inter-aquifer mixing occurs. The connection of shallow and deeper aquifers poses a risk for the groundwater resources in Gippsland as contaminants can migrate across aquifers and dewatering of shallow units may impact deeper parts of the groundwater system. 相似文献
13.
Salt lakes and salt efflorescences are a common phenomenon of many arid zones. Rocks weather rapidly in the presence of saline materials, and the rate of such weathering may be controlled by the mineralogy of the salts concerned. The distribution of the main salt types is presented for the polar deserts of Antarctica and the Arctic, and for the warmer deserts of Australia, North America, South America, Africa and Asia. There is great variety in the types of salts encountered and marked differences between different regions, with, for example, Australia being dominated by sodium chloride (halite) and southern Canada by the sulphates of magnesium and sodium. The possible causes of such variability and its pattern are analysed in terms of the nature of inputs into drainage basins and the various changes that take place within basins. Finally, it is apparent that in those situations when weathering has been observed as an active process there are a great many different salts involved. 相似文献
14.
Major ion and stable isotope geochemistry allow groundwater/surface-water interaction associated with saline to hypersaline lakes from the Willaura region of Australia to be understood. Ephemeral lakes lie above the water table and locally contain saline water (total dissolved solids, TDS, contents up to 119,000 mg/L). Saline lakes that lack halite crusts and which have Cl/Br ratios similar to local surface water and groundwater are throughflow lakes with high relative rates of groundwater outflows. Permanent hypersaline lakes contain brines with TDS contents of up to 280,000 mg/L and low Cl/Br ratios due to the formation of halite in evaporite crusts. These lakes are throughflow lakes with relatively low throughflow rates relative to evaporation or terminal discharge lakes. Variations in stable isotope and major ion geochemistry show that the hypersaline lakes undergo seasonal cycles of mineral dissolution and precipitation driven by the influx of surface water and evaporation. Despite the generation of highly saline brines in these lakes, leakage from the adjacent ephemeral lakes or saline throughflow lakes that lack evaporite crusts is mainly responsible for the high salinity of shallow groundwater in this region. 相似文献
15.
Basin hydrogeological characterization using remote sensing,hydrogeochemical and isotope methods (the case of Baro-Akobo,Eastern Nile,Ethiopia) 总被引：1，自引：0，他引：1
Hydrogeochemical and isotopic signatures of the waters of the Baro-Akobo River Basin show deviation from signatures in other Ethiopian river basins. In this study, hydrogeochemical and isotope methods were employed to determine regional and local hydrogeology and characteristics of the basin. Optical, thermal and radar remote sensing products were used to update geological and structural maps of the basin and determine sampling points using the judgment sampling method. A total of 363 samples from wells, springs, rivers, lakes, swamps and rain were collected for this study, and an additional 270 water quality data sets were added from previous studies. These data were analyzed for their hydrogeochemical characteristics and isotope signatures. Analysis of the oxygen, deuterium and tritium isotopes shows the groundwater of the basin is modern water. Among all basins in Ethiopia, the Baro-Akobo Basin shows the highest enrichment. This indicates the proximity of the rainfall sources, which presumably are the Sudd and other wetlands in South Sudan. The hydrochemical properties of the waters show evapotranspiration is the dominant hydrologic process in the basin and explains the large amount of water that is lost in the lowland plain. Analysis of radon-222 shows no significant groundwater flux over the wetlands, which are part of Machar Marshes. This shows evaporation to be dominant hydrologic process in this zone. Results from all analyses help explain the limited holding capacity of the aquifers in the recharge zone and their vulnerability to anthropogenic impacts and climate variability. There is a trend of decreasing surface flow and rainfall and increasing water soil erosion. 相似文献
16.
V. P. Parnachev D. Banks A. Y. Berezovsky D. Garbe-Schönberg 《Hydrogeology Journal》1999,7(6):546-560
The Shira region of Khakassia in southern Siberia exhibits many features governing the evolution of groundwater and surface-water
chemistry that are common to other cold, semi-arid areas of the world: (1) a continental climate, (2) location in a rain shadow,
(3) low density of surface-water drainage, (4) occurrence of saline lakes, and (5) occurrence of palaeo- and modern evaporite
mineralisation. In lowland areas of Shira, the more saline groundwaters and lake waters have a sodium-sulphate (-chloride)
composition. Results of thermodynamic modelling suggest that these evolve by a combination of silicate weathering and gypsum
and halite dissolution, coupled with carbonate precipitation to remove calcium and bicarbonate ions. An approximately 1:1
sodium:sulphate ratio occurs even in groundwaters from non-evaporite-bearing aquifers. This may indicate the formation of
secondary sodium sulphate evaporites (in or near saline lakes or in soil profiles where the water table is shallow), which
are subsequently distributed throughout the study area by atmospheric transport. Several urban groundwaters are characterised
by very high nitrate concentrations, conceivably derived from sewage/latrine leakage.
Received, June 1998 /Revised, May 1999, August 1999 /Accepted, August 1999 相似文献
17.
塔城盆地地下水氟分布特征及富集机理 总被引：2，自引：0，他引：2
塔城盆地位于新疆维吾尔自治区西北部,干旱少雨,蒸发强烈。但相对于新疆其他盆地,塔城盆地地下水水质相对较好,溶解性总固体和F-含量相对较低。为解译这种差异及盆地内高氟地下水的成因,本文在对盆地地下水样品水化学组分系统分析的基础上,结合多种水文地质调查数据,利用数理统计、离子比及主成分分析等手段,研究高氟水的成因及其分布规律。结果表明:受气候以及地质等因素控制,研究区地下水氟浓度总体较低,高氟水主要分布于扇前洼地及盆地中部的低洼地带;受承压含水层的顶托补给,地下水氟浓度呈现出上高下低的垂向分带特征。研究区地下水径流途径短,水循环快,水岩相互作用时间较短,且山区地下水以深径流形式循环补给平原区深层承压含水层,再顶托补给潜水,避免了强烈的蒸发浓缩作用。山前洪积扇地下水氟富集主要受控于沉积地层中含氟矿物的风化溶解,而岩石风化、蒸发浓缩、阳离子交换、竞争吸附为平原区地下水氟浓度的主要影响因素。 相似文献
18.
Groundwater recharge and chemical evolution in the southern High Plains of Texas, USA 总被引：3，自引：1，他引：3
The unconfined High Plains (Ogallala) aquifer is the largest aquifer in the USA and the primary water supply for the semiarid
southern High Plains of Texas and New Mexico. Analyses of water and soils northeast of Amarillo, Texas, together with data
from other regional studies, indicate that processes during recharge control the composition of unconfined groundwater in
the northern half of the southern High Plains. Solute and isotopic data are consistent with a sequence of episodic precipitation,
concentration of solutes in upland soils by evapotranspiration, runoff, and infiltration beneath playas and ditches (modified
locally by return flow of wastewater and irrigation tailwater). Plausible reactions during recharge include oxidation of organic
matter, dissolution and exsolution of CO2, dissolution of CaCO3, silicate weathering, and cation exchange. Si and 14C data suggest leakage from perched aquifers to the High Plains aquifer. Plausible mass-balance models for the High Plains
aquifer include scenarios of flow with leakage but not reactions, flow with reactions but not leakage, and flow with neither
reactions nor leakage. Mechanisms of recharge and chemical evolution delineated in this study agree with those noted for other
aquifers in the south-central and southwestern USA.
Electronic Publication 相似文献
19.
Mitja Janža 《Environmental Earth Sciences》2010,61(5):909-920
Karst aquifers are known for their heterogeneity and irregular complex flow patterns which make them more difficult to model
and demand specific modeling approaches. This paper presents one such approach which is based on a conceptual model. The model
was applied in a karst area of the catchment of Rižana spring (200 km2). It is based on the MIKE SHE code and incorporates
the main hydrological processes and geological features of the karst aquifer (diffuse and concentrated infiltration, allogenic
recharge, quick and slow groundwater flow, shifting groundwater divides and groundwater outflow from the catchment area).
Modeling of evapotranspiration and flow in the upper part of the unsaturated zone is more detailed. For the modeling of groundwater
flow in the karst aquifer, a conceptual model was applied which uses drainage function for the simulation of groundwater flow
through large conduits (karst channels and large fissures). The model was calibrated and validated against the observed Rižana
spring discharge which represents a measured response of the aquifer. The results of validation show that the model is able
to adequately simulate temporal evolution of the spring discharge, measured by Nash–Sutcliffe coefficient (0.82) as well as
overall water balance. 相似文献
20.
Origin of saline waters in the Shiraz-Sarvistan area, Iran, is determined by a combined isotopic (18O and D) and chemical characterization. Four types are recognized: (a) fresh water of the anticlinal carbonatic aquifer; (b) fresh and brackish runoff in the synclinal basins; (c) salt springs originating through dissolution of rock salt by type (a) fresh water; and (d) residual brines formed in synclinal closed drainage basins, through evaporation of former water types and loss of the relatively less-soluble salts. 相似文献