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1.
Investigation of water sources and flow pathways is crucial to understand and evaluate the characteristics of surface water and groundwater systems. This article aims to identify the hydrochemical and hydrological processes in different landscape zones based on hydrochemical analyses of various samples, including samples from glacier, snow, frozen soil meltwater, surface water, groundwater, and precipitation, in the alpine cold region of China. Hydrochemical tracers indicated that chemical compositions are characterized by the Ca-HCO3 type in the glacier-snow zone; the Mg-Ca-SO4 type in the alpine cold desert zone; the Ca-HCO3-SO4 type in the marsh meadow zone; the Ca-Mg-HCO3 type in the alpine shrub zone; and the Ca-Na-SO4 type in the mountain grassland zone. An end-member mixing model was used for hydrograph separation. The results showed that the Mafengou River in the wet season was recharged by groundwater in the alpine cold desert and alpine shrub zones (67%), surface runoff in the glacier-snow zone (11%), surface runoff in the alpine cold desert zone (8%), thawed water from frozen soil in the marsh meadow and mountain grassland zones (9%), and direct precipitation on the river channel (5%). This study suggests that precipitation from the whole catchment yielded little direct surface runoff; precipitation was mostly transformed into groundwater or interflow and was then concentrated into the river channel. This study provides a scientific basis for evaluation and management of water resources in the basin.  相似文献   

2.
根据实地考察和相关参考资料,运用历史文献和统计分析的方法,对托木尔峰国家级自然保护区垂直自然带景观特征进行分析,结果显示：对托木尔峰自然保护区垂直自然带的形成,地形地貌因素起着主导作用,纬度起着次要作用,受地形地貌因素制约的水热条件是形成各垂直自然带景观特征的最重要的物质和能量来源,随着水热条件的垂直变化,从低山带至高山带有规律的出现暖温带荒漠带、温带荒漠草原带、山地草原带、亚高山草甸带、高山草甸带、高山垫状植被带和高山冰雪带.东西走向的天山山脉,南北向深切的冰川和流水地貌,对来自北大西洋和北冰洋的湿润气流起了显著地屏障作用,致使托木尔峰南、北坡具有不同的气候特点,南坡形成了暖温带半干旱和干旱气候.自然景观以温带荒漠、荒漠草原和草原为主,植物种类贫乏,具有耐旱特点,随着海拔高度的增加,植物的荒漠成分逐渐减少,草原和草甸成分逐渐增加,土壤的有机质含量提高,碳酸盐的淋溶作用增强.  相似文献   

3.
The mechanism of Au dispersion in sediments of mountainous desert environments has been studied in two different areas of the Chilean Andes. The San Pedro de Cachiyuyo placer (ca. 1800 m a.s.l.) consists of alluvial fans and ephemeral stream sediments deposited in a stable piedmont. The primary Au source is Cu–Au-bearing hydrothermal tourmaline breccia. The relief of this area is low (1850 m) and the average annual rainfall is ca. 20 mm. The La Coipa area (ca. 4000 m a.s.l.) is characterized by a rugged relief. The annual average rainfall is ca. 100 mm. The sedimentary deposits are less sorted than in San Pedro de Cachiyuyo and consist of ephemeral stream alluvium and slope deposits formed in a periglacial environment. The primary Au sources are two volcanic-hosted epithermal precious metal deposits. At San Pedro de Cachiyuyo, the halo is less than 1 km in length and the highest Au concentration are observed at the break in slope between the hillside and the piedmont. In the La Coipa area, Au was only detected by chemical analysis in the 125–63 μm and <63 μm fraction; however, the dispersion halo extends for over 10 km from the source. In both cases the geochemical signal of gold was strongest in the fraction <63 μm.  相似文献   

4.
Hydrogeochemistry and environmental tracers (2H, 18O, 87Sr/86Sr) in precipitation, river and reservoir water, and groundwater have been used to determine groundwater recharge sources, and to identify mixing characteristics and mineralization processes in the Manas River Basin (MRB), which is a typical mountain–oasis–desert ecosystem in arid northwest China. The oasis component is artificial (irrigation). Groundwater with enriched stable isotope content originates from local precipitation and surface-water leakage in the piedmont alluvial–oasis plain. Groundwater with more depleted isotopes in the north oasis plain and desert is recharged by lateral flow from the adjacent mountains, for which recharge is associated with high altitude and/or paleo-water infiltrating during a period of much colder climate. Little evaporation and isotope exchange between groundwater and rock and soil minerals occurred in the mountain, piedmont and oasis plain. Groundwater δ2H and δ18O values show more homogeneous values along the groundwater flow direction and with well depths, indicating inter-aquifer mixing processes. A regional contrast of groundwater allows the 87Sr/86Sr ratios and δ18O values to be useful in a combination with Cl, Na, Mg, Ca and Sr concentrations to distinguish the groundwater mixing characteristics. Two main processes are identified: groundwater lateral-flow mixing and river leakage in the piedmont alluvial–oasis plain, and vertical mixing in the north oasis plain and the desert. The 87Sr/86Sr ratios and selected ion ratios reveal that carbonate dissolution and mixing with silicate from the southern mountain area are primarily controlling the strontium isotope hydrogeochemistry.  相似文献   

5.
以黑河流域中游绿洲区域为例,近10年来,在干旱内陆流域受人类活动强烈影响的区域,景观的破碎度降低,景观异质性减弱,显著的景观变化表现在:耕种景观与荒漠化景观的扩张和沼泽草甸景观与水域景观的萎缩,其中荒漠草原景观面积的10%、山地草原景观的49.8%以及沼泽草甸(包括盐化草甸)景观面积的16.8%演变为耕种景观类型;相反,17.4%的荒漠草原景观面积和20.2%的沼泽草甸退化为沙漠与戈壁景观,另有13.02%的灌耕地面积演变为荒漠草原.景观空间格局演变驱动景观土壤N、C的源汇变化,近10年来,黑河流域中游地区由于景观空间格局变化形成的景观N净排放和有机C净释放分别达到50.65×104T和530.17×104T.山地草原景观的荒漠化与耕种利用、耕种景观的荒漠草原化、沼泽草甸与山地草甸景观以及荒漠草原景观的耕种利用和这些景观的沙漠化发展是造成区域N、C损失的主要途径.  相似文献   

6.
Hydrogeomorphological, hydrogeological and geophysical investigations were carried out in the Pageru River basin of Cuddapah district, Andhra Pradesh, to delineate potential zones for future groundwater exploration. The study area is underlain by Proterozoic formations of the Indian Peninsula comprising limestones and shales as the sedimentary cover. Limestone and shale formations of the Cuddapah Super group that are later overlain by the Kurnool group (shale, limestone and quartzite) are exposed extensively. The high drainage density (2.61 km/km2) in the western region also suggests that the area is characterized by low permeable zones compared with low drainage density (1.04 km/km2) of the flood plains, which form the potential aquifers in the east. The hydro-geomorphological data are further supported from evidence of the water-table fluctuation in wells and resistivity of the saturated formations. The results indicate that the favourable, moderately favourable and poor zones characterized geomorphologically, have water-level fluctuations in the range of 0–2, 2–6 and above 6 m, respectively. The resistivities of these zones are also in the range of 1–26, 40–466, and >1,900 ohm-m. A few pumping tests have also been conducted to assess the broad range in the values of aquifer parameters. Based on these data, good to poor potential zones for obtaining groundwater have been delineated in the study area.
Resumen Se llevaron a cabo investigaciones hidrogeomorfológicas, hidrogeológicas y geofísicas en la cuenca del Río Pageru del distrito Cuddapah, Andhra Pradesh, con objeto de delimitar zonas potenciales para exploración futura de aguas subterráneas. El área de estudio consiste de formaciones Proterozoicas de la Península India con calizas y lutitas como cubierta sedimentaria. Las formaciones de caliza y lutita del Grupo Cuddapah Superior afloran extensamente y están cubiertas por el Grupo Kurnool (lutita, caliza, y cuarcita). La alta densidad de drenaje (2.61 km/km2) en la región occidental también indica que el área se caracteriza por zonas de baja permeabilidad en comparación con las planicies de inundación de baja densidad (1.04 km/km2) que forman los acuíferos potenciales del oriente. Los datos hidrogeomorfológicos tienen apoyo adicional a partir de evidencia proveniente de la fluctuación del nivel freático en pozos y resistividad de las formaciones saturadas. Los resultados indican que las zonas caracterizadas geomorfológicamente como zonas favorables, moderadamente favorables, y pobres tienen fluctuaciones de niveles de agua en el rango de 0–2, 2–6, y mayor de 6 m, respectivamente. Las resistividades de estas zonas también se encuentran en el rango de 1–26, 40–466, y mayores de 1,900 ohm-m. Se realizaron algunas pruebas de bombeo para evaluar los amplios rangos que tienen los valores de los parámetros de los acuíferos. Basado en esta información se delimitaron zonas con potencial bueno a pobre para obtener agua subterránea en la zona de estudio.
Résumé Des investigations hydrogéomorphologiques, hydrogéologiques et géophysiques ont été menées sur le bassin de la rivière Pageru du district de Cuddapah, Andhra Pradesh, pour délimiter les zones potentielles dans la future recherche deaux souterraines. La zone étudiée est, à la base, constituée par les formations protérozoïques de la péninsule indienne comprenant les calcaires et les shales de la couverture sédimentaire. Les calcaires et les shales du Super Groupe Cuddapah qui sont recouverts par le Groupe Kurnool (shale, calcire, quartzite) sont exposés de manière extensive. La densité importante de drainage (2.61 km/km2) dans la région ouest montre également que la zone est caractérisée par des perméabilités faibles par comparaison avec les plaines dinondation (densité de drainage: 1.04 km/km2), formant les aquifères potentiels de lEst. Les données hydrogéomorphologiques vont également dans le sens des données de fluctuation de la nappe et de résistivité des formations saturées. Les résultats indiquent que les zones caractérisées géomorphologiquement comme favorables, moyennement favorables et pauvres, possèdent des fluctuations respectives de lordre de 0 à 2, 2 à 6 et de plus de 6 m. La résistivité de ces zones est également de lordre de 1 à 26, 40 à 466 et de plus de 1900 ohm-m. Quelques pompages dessais ont également été conduits pour déterminer les valeurs moyennes des paramètres de laquifère. En se basant sur ces données, des zones potentielles bonnes à pauvres pour lexploitation des eaux souterraines ont été délimitées.
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7.
西宁黄土堆积记录的最近13万年高原季风气候变化   总被引：21，自引：6，他引：21       下载免费PDF全文
青藏高原对于大气的热力和动力作用形成了高原季风气候现象.青藏高原东北部西宁盆地位于高原季风控制区,末次间冰期以来的黄土堆积记录了高原季风气候变化过程.对西宁盆地湟水阶地上的黄土堆积进行了地貌观查、地层对比和探槽及探井采样,完成了热释光和光释光测年,测量了古地磁定向样品以及磁化率、频率磁化率、CaCO3含量和粒度等古气候代用指标.结果表明,西宁黄土堆积记录的高原夏季风环流在相当于深海氧同位素阶段5e特别强,在5a和5c阶段接近于阶段3.高原夏季风和冬季风变化存在位相差以及冬季风强的时候夏季风不一定弱,夏季风弱的时候冬季风不一定强的变化模式.  相似文献   

8.
Zhangye Basin, in arid northwestern China, has recently been repeatedly flooded by rising groundwater. Isotope signatures of sampled waters gained insight into the recharge source of the groundwater. The summer Heihe River water and most of the spring water in Zhangye and Yongchang basins plotted above the global meteoric water line (GMWL) on the δ18O-δD plot. The spring water had R/Ra ratio >1, low TDS and high tritium, which indicates origin from Qilian Mountain glacier meltwater. The groundwater of Qilian Mountains was transported to the Hexi Corridor (in which Zhangye Basin is located) through underground fault zones. Additionally, some of the groundwater in the alluvial plain, and all spring water surrounding Zhangye Basin, plotted below the GMWL on the δ18O-δD plot along an evaporation line, and had R/Ra ratio?<?1 and high TDS. It is proposed that the Tibetan rivers or lakes source the Hexi Corridor groundwater through either the NE-trending or NW-trending buried fault zones. The isotopic signatures presented as part of this study rule out the conventional viewpoint that groundwater of the Zhangye Basin was recharged by local precipitation and infiltration of Heihe River water on the alluvial plain.  相似文献   

9.
Summary This paper describes corundum formation in a metasomatic reaction zonation around an ultramafic body within a metapelitic sequence. The investigated body is about 100 m in diameter and is located in the Saualpe of the Austroalpine nappe complex in the Eastern Alps. The body is surrounded by a 10 m wide reaction zone (here called zone 3) containing the paragenesis garnet–staurolite–biotite–margarite–chlorite–corundum. Beyond a further metasomatic transition zone (here called zone 2), there are undisturbed metapelitic host rocks (zone 1) that have the metamorphic peak paragenesis garnet–biotite–plagioclase–staurolite–muscovite–quartz. It is shown that reaction zonation formed around 7.2kbar and 615°C during regional metamorphism, just above the serpentine breakdown reactions in the system MgO–SiO2–H2O. Detailed analysis of the whole rock compositions shows that the reaction zonation formed by infiltration metasomatism that caused significant mass loss in the two alteration zones. These zones are particularly depleted in SiO2, Na2O and possibly K2O. An XNa2O–XSiO2 thermodynamic pseudosection is presented that includes the parageneses of both the unaltered metapelitic host rock and the corundum-bearing parageneses. This suggests that the metasomatic process can be explained by the transfer of SiO2 and Na2O alone. We interpret that the process is driven by water liberated from the previously serpentinised ultramafic body during prograde dehydration during regional Eo-Alpine metamorphism. This fluid flowed outwards from the ultramafic body depleting the surrounding pelites in silica and causing margarite formation from plagioclase and muscovite. This interpretation of the driving mechanism is consistent with our knowledge of the low water activities of the Saualpe during the Eo-Alpine orogenic cycle.  相似文献   

10.
The hydrological response of the Choshuishi alluvial fan to the 1999 Chi-Chi earthquake shows that the earthquake did impact the aquifer. The possible earthquake-induced changes in hydrogeological properties were investigated in this study. First, contour maps of the hydrologic anomaly, seismic factors, and vertical ground-surface displacement were compared qualitatively. Bulls eye patterns were found on the contour maps of hydraulic conductivity, coseismic groundwater-level change and vertical ground-surface displacement but did not occur with other seismic factors. The more permeable zones of the aquifer were found to coincide with the locations of greater vertical ground-surface displacement and coseismic groundwater-level change in the 1999 Chi-Chi earthquake. This indicates that the change of the hydrogeologic properties of Choshuishi alluvial fan due to the 1999 Chi-Chi earthquake may have mainly occurred in the highly permeable zones. Fractal, cross semivariogram and cross correlogram analyses were performed to quantitatively measure the persistency, variability and similarity, respectively, of spatial hydrologic response, seismic factors and hydraulic conductivity. The groundwater-level change, earthquake intensity, and vertical ground-surface displacement were found to show antipersistent tendencies while other factors showed the opposite. Higher correlations were found between hydraulic conductivity and groundwater-level change in aquifers 2–1 and 2–2, and between hydraulic conductivity and vertical ground-surface displacement in aquifer 3. Changes in porosities and hydraulic conductivity were evaluated in the main aquifers of the Choshuishi alluvial fan based on the data of hydrologic anomaly and the vertical ground-surface displacement. While both approaches show that the 1999 Chi-Chi earthquake has impacted the Choshuishi alluvial fan by reducing its porosity and hydraulic conductivity, these changes were not significant relative to natural variation in hydraulic conductivity.This revised version was published in May 2005 with correction to the rubric.  相似文献   

11.
黑河干流浅层地下水与地表水相互转化的水化学特征   总被引：14，自引：0，他引：14  
通过分析黑河干流地表水与地下水的水化学特征,识别沿黑河干流不同地带地下水与地表水的相互转化关系.研究结果表明:(1)在祁连山区,地下水与地表水的转化以地下水向河流排泄为主.(2)南部盆地,在山前戈壁带,出山河水入渗转化为地下水;溢出带地下水以泉的形式转化为地表水;进入细土平原后,汛期河水补给地下水,非汛期地下水补给河水;在农灌区引河水通过田间入渗补给地下水.(3)北部盆地,在金塔灌区,地下水主要接受引水灌溉入渗补给;在金塔灌区到额济纳旗,河流入渗转化为地下水.  相似文献   

12.
Madeira Island is a hot-spot originating from a mantle plume. K-Ar age determinations indicate that the emerged part of the island was generated during Post-Miocene times 6000–7000 years B.P. Groundwater occurs in perched-water bodies, spring discharge from them is high, about 3,650 l/s; in dike-impounded water and basal groundwater. Basal groundwater is exploited by tunnels (1,100 l/s) and wells (1,100 l/s). Hydraulic gradients range from 10–4 to 10–2 and transmissivity ranges from 1.16×10–2 to 2.89×10–1 m2/s, indicating the heterogeneity of the volcanic aquifers. Water mineralisation is variable, and electrical conductivity ranges from 50 to 3,300 S/cm. There is a difference between groundwater discharging from perched-water bodies (43–201 S/cm) and from basal groundwater (109–3,300 S/cm). Groundwater average pH is 7.37, with waters acid to slightly alkaline (6.13–8.4), and generally cold. Nevertheless, a few samples associated with fault zones can be classified as thermal waters.
Resumen La Isla de Madeira tuvo origen en un punto caliente proveniente de una pluma del manto. Las dataciones K – Ar, indican que la parte emergida de la isla se formó durante en Post—Mioceno, hace unos 6000–7000 años. El agua subterránea se encuentra en acuíferos colgados, cuya descarga a través de manantiales es alta, alrededor de 3650 l/s; también como agua retenida en diques o bien como agua subterránea propiamente dicha. Esta última es explotada por túneles (1100 l/s) y pozos (1100 l/s). Los gradientes hidráulicos varían desde 10–4 hasta 10–2 y la transmisividad varía desde 1.16×10–2 hasta 2.89×10–1 m2/s, indicando la heterogeneidad de los acuíferos volcánicos. La mineralización de agua es variable y la conductividad eléctrica varía desde 50 mS/cm hasta 3300 mS/cm. Hay una diferencia entre el agua subterránea proveniente de acuíferos colgados (43–201 mS/cm) y aquella del acuífero principal (109–3300 mS/cm). El pH promedio para el agua subterránea es 7.37; con variación desde ácida hasta ligeramente alcalina (6.13–8.4), y es generalmente fría. Sin embargo unos pocos ejemplos asociados con zonas de falla, pueden ser clasificados como agua termal.
Résumé Lîle de Madeira est un point chaud, provenant dun panache mantélique. Les datations par la méthode de K-Ar indiquent que la part émergée de lîle a été générée pendant le Post Miocène, il y a 6000–7000 ans. Les eaux souterraines sont cantonnées dans des aquifères perchées qui se déchargent par des sources à grands débits, avec des valeurs dapproximativement de 3500 l/s, ainsi que dans les dikes. Une importante quantité des eaux souterraine se trouve sur la forme deau de fonds, formant une nappe basale, qui est exploitée par des tunnels (1100 l/s) et par des puits (1100 l/s). Les gradients hydrauliques ont des valeurs dans lintervalle de 10–2 à 10–4, tandis que les transmissivités se rangent entre 1.16×10–2 m2/s et 2.81×10–1 m2/s, ce quindique la hétérogénéité de laquifère volcanique. La minéralisation des eaux est aussi variable avec des conductivités électriques qui se rangent ente 50 mS/cm et 3300 mS/cm. Il y a une différence entre la conductivité des eaux provenant des aquifères perchées (30–201 mS/cm) par rapport à la conductivité les eaux de la nappe basale (109–3300 mS/cm). Le pH moyen est de 7.37 avec des valeurs de 6.13 pour les eaux acides et de 8.4 pour les eaux à faible alcalinité. En général il sagit des eaux froides, mais quelques échantillons provenant des zones faillées peuvent être classifiés comme des eaux thermales.
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13.
袁复礼 《第四纪研究》1993,13(4):354-360
下面发表的这篇手稿,可能是80年代袁老在整理其参加西北科学考察团阶段的笔记而写出的。可以看出,早在1927—1932年他就在地质考察中进行综合性的观察和纪录,他对天山—准噶尔盆地之间地貌分带的描述生动如画——“天山雪云常不开”“万里栏杆千丈冰”,锵锵有声——“隆隆震耳类似滚雷”,使你对皑皑白雪分布的山顶带和霜劈、冻土现象为主的崩塌带有如身临其境的感觉。往下是两级高山夷平面所构成的高、低草原带,它们之间以悬崖陡坎带相连,从生物和人类在这三带的活动来反映这三带的地形、植被和气候。再往下黄土开始出现;山前阶地十分发育;乌鲁木齐市所在的山前夷平面和由不同外力作用所形成的各成因类型沉积物堆积带……,它们表面的地貌特征、沉积特点以及生物状态,甚至看到风力剥蚀带所裸露的动植物化石、琳琅满目的风蚀石……。这些生动的描绘和深刻的分析,显示出袁老师的敏锐观察和丰富联想,是一篇宝贵的科学资料。  相似文献   

14.
Groundwaters from crystalline and metamorphic rocks (hardrocks) and from Quaternary deposits, i.e., alluvial and glacial deposits (softrocks) from the counties of Nord-Trøndelag and Sør-Trøndelag were analyzed for major and minor elements and ions including fluoride. The median concentration of F– in water from the hardrock aquifers is 0.28 mg/l (14.7 eq/l) in contrast to water from softrock aquifers in which it is found to be 0.05 mg/1 (2.6 eq/l). More importantly, ca. 15% of the locations where water was abstracted from hardrock wells contain 1.5 mg/l (78.9 eq/l) F– or more. Thus, 15% of all hardrock wells returned F– results that are at or above the maximum recommended value for drinking water. Of the softrock wells, none are above 1 mg/l. Geologists would normally expect higher F–contents in groundwaters derived from acid rocks, e.g., in granitic or gneissic areas. When comparing the host lithology with the observed F–contents, however, no clear relationship between F– content and lithology is visible. The highest observed F– values actually occur in gneissic host rocks. However, wells drilled in amphibolites/greenstones, mica schists, calcareous rocks, and sedimentary rocks all returned some analytical results above 1.5 mg/l F–. These results suggest that all hardrock wells drilled should be tested for F– and the users informed about the results and advised to take any necessary precautions. When applying the recently proposed Norwegian drinking water limits to our data, 51% of all softrock well waters and 56% of all hardrock well waters are unfit for consumption without prior treatment, although we analyzed only for about half of the proposed elements/parameters. This result seriously questions the concept of fixed action levels—many of them with totally unproven health implications—for so many parameters/elements for hardrock groundwaters.  相似文献   

15.
Ferromanganese micro- and macronodules in eupelagic clays at Site 35 of the South Basin were examined in order to check the REE distribution during the ferromanganese ore formation in nonproductive zones of the Pacific Ocean. We studied host sediments and their labile fraction, ferromanganese micronodules (fractions 50–100, 100–250, 250–500, and >500 m) from eupelagic clays (horizons 37–40, 105–110, 165–175, and 189–190 cm), and buried ferromanganese micronodules (horizons 64–68, 158–159, and 165–166 cm). Based on phase analysis data, the anomalous REE enrichment of eupelagic clays from Site 35 is related to the accumulation of rare earth elements in iron hydroxophosphates. The Ce concentration, generally linked to manganese oxyhydroxides, is governed by the oxidation of Mn and Ce in oceanic surficial waters. Micronodules (Mn/Fe = 0.7–1.6) inherit compositional features of the labile fraction of sediments. The Ce, Co, and Th concentrations depend on the micronodule dimension. The enrichment of micronodules in hydrogenic or hydrothermal substance is governed by their dimension and the dominant source of suspended oxyhydroxide material. The study of buried ferromanganese micronodules revealed general regularities in the compositional evolution of oxyhydroxide matrices of ferromanganese micro- and macronodules. The compositional variation of micro- and macronodules, relative to the labile fraction of sediments, in the Pacific nonproductive zone dramatically differs from the pattern in bioproductive zones, where micronodule compositions in larger fractions are similar to those in associated macronodules and labile fractions of the host sediment as a result of the more intense suboxidative diagenesis.  相似文献   

16.
高山寒漠带是我国内陆河山区和我国多数大江、大河源头的主产流区之一. 由于缺乏系统观测数据及相关研究的支撑,当前国内外研究较为匮乏,高山寒漠带水文循环过程机理尚不清楚. 通过在黑河上游葫芦沟流域高山寒漠带试验点布设水文循环观测试验,分析了典型高山寒漠带非冻结期水文特征. 结果表明：高山寒漠试验点观测期(2009年6月7日-9月30日)的降水量为541.4 mm;蒸发皿的蒸发量为256.9 mm,桶式微型蒸渗仪(Micro-Lysimeter)的蒸发量为122.8 mm,平均蒸发量为1.1 mm·d-1. 根据观测,高山寒漠带凝结水量也比较丰富,凝结水虽然没有直接参与高寒山区水文循环的产汇流过程,但它消耗了能量,抵消了部分太阳辐射,间接地参与了产汇流过程. 高山寒漠带小流域在观测期的平均径流深为461.2 mm. 根据降水梯度获取的流域平均降水量为639.1 mm,径流系数为0.72.  相似文献   

17.
The recharge sources, the flow mechanisms and discharge areas of the different groundwater bodies underlying the Yarmouk River catchment area in Jordan, have, until now, not been adequately explained, although a wide range of hydrological, hydrogeological, and hydrochemical studies have been done. Along the Jordanian part of the catchment area of the Yarmouk River, groundwater issues from different aquifers with a variety of chemistries and types within the same aquifer and in between the different aquifers. Conventional recharge/discharge mechanisms, water balances and chemical analyses did not adequately explain the chemical variations and the different water types found in the area. Applying environmental isotopic tools combined with their altitude effects due to topographic variations (250–1,300 m a.s.l. within a distance of 20 km), and taking into consideration re-evaporation effects on the isotopic depletion and enrichment of rainwater, has greatly helped in understanding the recharge discharge mechanisms of the different aquifers. Precipitation along the highlands of an average of 600 mm/year is found to be depleted in its isotopic content of O18 = –7.0 to –7.26 and D = –32.2 to –33.28, whereas that of the Jordan Valley of 350 mm/year is highly enriched in isotopes with O18 = –4.06 and D = –14.5. The groundwater recharged along the highlands is depleted in isotopes (O18 = ~ –6, D = ~ –30), groundwater at the intermediate elevations is enriched (O18 = ~ –5, D = ~ –23) and that of the Jordan Valley aquifers containing meteoric water is highly enriched (O18 ~ –3.8, D = ~ –18). The deep aquifers in the Jordan Valley foothills are depleted in isotopes (O18 –18 = –6, D = –30) and resemble those of the highland aquifers. Only through using isotopes as a tool, were the sources of the different groundwater bodies and recharge and discharge mechanisms unambiguously explained. It was found that recharge takes place all over the study area and produces groundwater, which, from the highlands towards the Jordan Valley, shows increasing enrichment in isotopes. The highlands aquifer, with its groundwater depleted in isotopes, becomes confined towards the Jordan Valley; and, due to its confining pressure, leaks water upwards into the overlying aquifers causing their water to become less enriched in isotopes. Water depleted in its isotopic composition also seeps upward to the ground surface at the mountain foothills through faults and fissures.
Resumen Las fuentes de recarga, los mecanismos de flujo y las áreas de descarga de los diferentes cuerpos de agua subterránea que subyacen el área de la cuenca del Río Yarmouk en Jordania, se han explicado de manera no ambigua únicamente mediante la aplicación de los isótopos como herramienta. A lo largo de la parte Jordana del área de la cuenca del Río Yarmouk el agua subterránea emerge de diferentes acuíferos con una variedad de tipos y composiciones, ya sea que provengan del mismo acuífero o de diferentes acuíferos. Los mecanismos convencionales de recarga/descarga, balances hídricos y variaciones químicas no han podido explicar las variaciones químicas y los diferentes tipos de aguas. La aplicación de herramientas de isótopos ambientales combinadas con los efectos de altitud derivados de variaciones topográficas (250 hasta 1,300 m s.n.m. en una distancia de 20 km) y tomando en consideración los efectos de re-evaporación en el empobrecimiento de isótopos y enriquecimiento del agua de lluvia han ayudado fuertemente en el entendimiento de los mecanismos de recarga/descarga de los diferentes acuíferos. La precipitación en el área varía de 600 mm/año, a lo largo de las tierras altas, a 350 mm/año en el área del Valle Jordán. El flujo de agua subterránea ocurre de las tierras altas hacia el Valle Jordán. El agua subterránea de las tierras altas está empobrecida en isótopos (O18 =~ –6, D =~ –30), el agua subterránea de elevaciones intermedias está enriquecida (O18 =~ –5, D =~ –23), y el agua de los acuíferos del Valle Jordan contiene agua meteórica que se encuentra altamente enriquecida (O18 =~ –3.8, D =~ –18). Los acuíferos profundos que se localizan al pie de las tierras altas del Valle Jordán están empobrecidos en isótopos (O18 =~ –6, D =~ –30) y son similares a los acuíferos de las tierras altas. Solo al aplicar los isótopos ambientales como herramienta pudo explicarse de manera inequívoca las fuentes de los diferentes cuerpos de agua subterránea y los mecanismos de recarga y descarga.
Résumé Les zones de recharge, les mécanismes découlement et les zones de décharges des différentes masses deau souterraine sous le bassin versant de la rivière Yarmouk en Jordanie, étaient expliquées de manière ambiguë par les seuls outils isotopiques. Le long de la parti Jordanienne du bassin versant de la rivière Yarmouk leau souterraine provient de différents aquifères et se distinguent par leur type et leur composition chimique, selon que leau provient du même ou des différents aquifères. Les mécanismes conventionnels de recharge et de décharge, bilan hydrologique ne donnaient pas dexplications satisfaisantes concernant les variations chimiques et les différents types deau. En appliquant les isotopes environnementaux combinés aux effets de laltitude sur les variations des teneurs isotopiques (laltitude varie de 250 à 1,300 m sur une distance de 20 km.) et en prenant en considération les effets de ré-évaporation sur lappauvrissement et lenrichissement isotopique des eaux pluviales ont fortement contribués à une meilleure compréhension des mécanismes de recharge des différents aquifères. Les précipitations annuelles sont comprises entre 600 mm dans les zones en altitude et 350 mm dans la vallée de la Jordanie. Les écoulements de leau souterraine sont dirigés des zones en altitude vers la vallée de la Jordanie. Les eaux souterraines des zones en altitude sont isotopiquement appauvries (O18 = ~ –6, D = ~ –30), les eaux souterraines des zones de moyenne altitude sont enrichies (O18 = ~ –5, D = ~ –23) et les eaux de la vallée très enrichies (O18 ~ –3.8, D = ~ –18). Les aquifers profonds dans la vallée de la Jordanie sont appauvris (O18 –18 = –6, D = –30) et se confondent avec les eaux des zones situées en altitude. En appliquant uniquement les isotopes environnementaux comme des outils de compréhension des phénomènes hydrogéologiques, la source des différentes masses deau souterraines, les mécanismes de la recharge et de la décharge pourraient être expliqués de manière ambiguë.
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18.
The intramontane Lauca Basin at the western margin of the northern Chilean Altiplano lies to the west of and is topographically isolated from the well-known Plio-Pleistocene lake system of fluvio-lacustrine origin that covers the Bolivian Altiplano from Lake Titicaca to the north for more than 800 km to the Salar de Uyuni in the south. The Lauca Basin is filled by a sequence of some 120 m of mainly upper Miocene to Pliocene elastic and volcaniclastic sediments of lacustrine and alluvial origin. Volcanic rocks, partly pyroelastic, provide useful marker horizons. In the first period (6–4 Ma) of its evolution, the Lago Lauca was a shallow ephemeral lake. Evaporites indicate temporarily closed conditions. After 4 Ma the lake changed to a perennial water body surrounded by alluvial plains. In the late Pleistocene and Holocene (2-0 Ma) there was only marginal deposition of alluvial and glacial sediments. The basin formed as a half-graben or by pull-apart between 10 and 15 Ma (tectonic displacement of the basal ignimbrite sequence during the Quechua Phase) and 6.2 Ma (maximum K/Ar ages of biotites of tuff horizons in the deepest part of the basin). Apart from this early basin formation, there has been surprisingly little displacement during the past 6 Ma close to the Western Cordillera of the Altiplano. Also, climate indicators (pollen, evaporites, sedimentary facies) suggest that an arid climate has existed for the past 6 Ma on the Altiplano. Together, these pieces of evidence indicate the absence of large scale block-faulting, tilt and major uplift during the past 5–6 Ma in this area.  相似文献   

19.
Small alpine valleys usually show a heterogeneous hydraulic situation. Recurring landslides create temporal barriers for the surface runoff. As a result of these postglacial processes, temporal lakes form, and thus lacustrine fine-grained sedimentation intercalates with alluvial coarse-grained layers. A sequence of alluvial sediments (confined and thus well protected aquifers) and lacustrine sediments (aquitards) is characteristic for such an environment. The hydrogeological situation of fractured hard-rock aquifers in the framing mountain ranges is characterized by superficially high hydraulic conductivities as the result of tectonic processes, deglaciation and postglacial weathering. Fracture permeability and high hydraulic gradients in small-scaled alpine catchments result in the interaction of various flow systems in various kinds of aquifers. Spatial restrictions and conflicts between the current land use and the requirements of drinking-water protection represent a special challenge for water resource management in usually densely populated small alpine valleys. The presented case study describes hydrogeological investigations within the small alpine valley of the upper Gurktal (Upper Carinthia, Austria) and the adjacent Höllenberg Massif (1,772 m above sea level). Hydrogeological mapping, drilling, and hydrochemical and stable isotope analyses of springs and groundwater were conducted to identify a sustainable drinking-water supply for approximately 1,500 inhabitants. The results contribute to a conceptual hydrogeological model with three interacting flow systems. The local and the intermediate flow systems are assigned to the catchment of the Höllenberg Massif, whereas the regional flow system refers to the bordering Gurktal Alps to the north and provides an appropriate drinking water reservoir.  相似文献   

20.
The Wolyu mine is one of the largest vein-type gold-silver-bearing epithermal systems in the Youngdong district and is the first gold-silver deposit in Korea found to contain significant germanium, in the form of argyrodite (Ag8GeS6). Mineralized veins (78.9 ± 1.2 Ma) crosscutting Late Cretaceous hostrock tuff and quartz porphyry (81.5 ± 1.8 Ma) consist of three stages of quartz and carbonates, the first of which contains pyrite, basemetal sulfides and Au-Ag-minerals. Stage I Au-Ag-Ge-mineralized veins show a systematic variation of mineral assemblage with time: (1) quartz + pyrite; (2) quartz + pyrite + sphalerite + electrum + argentite; (3) carbonate + quartz + sphalerite + electrum + argentite; (4) carbonate + native silver + argentite + Ag-sulfosalts + argyrodite + sphalerite. Calculated values of temperature and sulfur activity are: assemblage (1), 360-280°C and 10–7-10–10; (2), 280-210°C and 10–10-10–14; (3), 210-180°C and 10–14-10–16; (4), 180-155°C and 10–17-10–18. These data, the frequent association of gold with sulfides, and the abundance of pyrite in alteration zones indicate that decreasing sulfur activity and cooling were important in triggering gold deposition. Hydrogen and oxygen isotope compositions of ore fluids display a systematic variation with increasing time. Within the main Ag-Au-Ge mineralization, D and 18O values decrease with the transition from quartz to carbonate deposition (from -78 and –2.8% to –90 and –8.7%., respectively), indicating increasing involvement (mixing) of less evolved meteoric water which resulted in progressive cooling and dilution of ore fluids in the shallow ( 370–600 m) Wolyu epithermal system.  相似文献   

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