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1.
青藏高原东部长江流域盆地陆地化学风化研究   总被引：4，自引：0，他引：4  
长江河水主要离子由流域盆地碳酸盐岩的风化所控制,沱沱河和楚玛尔河受蒸发盐岩影响较为明显;河水溶质载荷Si,Si/TZ *,Si/(Na* K)等指标表明,长江流域盆地地表硅酸盐岩风化还是浅表层次的;金沙江地表化学剥蚀速率为1.74×103mol/yr.km2,雅砻江为1.69×103mol/yr.km2,大渡河为1.57×103mol/yr.km2,岷江为1.88×103mol/yr.km2,长江河源区楚玛尔河为2.32×103mol/yr.km2,沱沱河为1.37×103mol/yr.km2,流域地表化学剥蚀速率可与世界上其它造山带的河流进行对比。  相似文献   

2.
2000-2002年期间,笔者对青藏高原东部长江流域溶质载荷分别进行了取样分析并对流域盆地化学剥蚀通量、剥蚀速率和大气CO2净消耗率进行了计算。结果表明,流域盆地化学剥蚀速率以河源区楚玛尔河最高为2.34×10^6mol/a/km^2,沱沱河最低为1.40×10^6mol/a/km^2,四大支流雅砻江为1.69×10^6mol/a/km^2,金沙江为1.74×10^6mol/a/km^2,大渡河为1.57×10^6mol/a/km^2,岷江为1.88×10^6mol/a/km^2;流域盆地ФCO2估算结果以大渡河最高为101.81×10^3mol/a/km^2,楚玛尔河最低为7.55×10^3mol/a/km^2,金沙江为44.38×10^3mol/a/km^2,雅砻江为69.64×10^3mol/a/km^2,岷江为81.90×10^3mol/a/km^2,沱沱河为21.90×10^3mol/a/km2^。并对长江流域地表化学剥蚀速率主要控制因素进行了讨论。  相似文献   

3.
赤水河上游流域水化学变化与离子成因分析   总被引：5，自引：0，他引：5       下载免费PDF全文
耿金  陈建生  张时音 《水文》2013,33(1):44-50
选取赤水河上游流域的河水为研究对象,研究分析了河水的水化学特性沿流域空间变化以及主要离子特别是SO42-的来源等内容.结果显示:赤水河水质属低矿化度硬水,HCO3-和Ca2+为河水中的主要阴阳离子,赤水河是典型的碳酸盐岩河流.以白沙河为界,上段河流水化学组成变化平稳,离子主要来源于天然环境的输入,白沙河下游河流各化学组分差异显著,分析是受一定人为因素的影响.SO42-为次要阴离子,占阴离子总量的30％,发现SO42-与Ca2+、HCO3-与Mg+相关性较好,HCO3-与Ca2+相关性差,推断SO42-来源于石膏的溶解.但石膏的溶解还不能完全解释SO42-的来源问题,经分析环境酸化也是一种影响河水中SO42-含量的重要方式.  相似文献   

4.
通过对四川省雅安龙苍沟峨眉山玄武岩小流域的水化学组成研究,分析了不同物质来源对小流域溪水溶解质的贡献,并对该小流域岩石风化速率和CO2消耗速率进行了估算。结果表明,龙苍沟流域溪水呈中性,PH平均值为6.82。溪水中阳离子以Ca^2+为主,约占阳离子总量的56%;阴离子以HCO3^-为主,约占阴离子总量的45%。碳酸盐岩风化、硅酸盐岩风化、大气降水和人为活动对溪水阳离子平均贡献率分别为50.2%、38.2%、10.5%和1.1%。流域硅酸盐岩风化速率为37.54±24.94 t/km^2/yr,硅酸盐岩风化对大气C02消耗速率为5.4±3.6 mol C/km^2/yr。本文首次对我国峨眉山玄武岩省化学风化大气CO2消耗量进行估算,得到其年消耗通量为1.35±0.89×10^11 mol C/yr,约为全球玄武岩CO2年消耗通量的3.31±2.18%。  相似文献   

5.
南水北调中线水源地河水地球化学特征与流域侵蚀   总被引：1，自引：0，他引：1  
丹江口水库及其上游流域是南水北调中线工程的水源地,本文讨论了水源地河流水化学与锶同位素(87Sr/86Sr)组成变化特征,目的在于了解水源地流域河流地表水溶质的物质来源以及岩石风化侵蚀过程和人为活动的影响。流域内河流水化学组成以Ca2+、HCO3-为主,Mg2+和SO42-次之,反映了碳酸盐岩风化溶解起控制作用的典型特征。水化学分析表明水源地河水受到工农业活动等人为因素的影响;河流87Sr/86Sr同位素地球化学研究表明,流域岩石风化输入至少存在三个不同端员(硅酸岩、石灰岩和白云岩)之间的混合。水源地流域内硅酸岩和碳酸岩的风化侵蚀速率分别为38.6和4.4 t/km2.a,总岩石风化侵蚀速率高于全球河流平均值。  相似文献   

6.
桂江流域河流水化学特征及影响因素   总被引：9，自引：5，他引：4  
2012年4月9-16日在桂江流域采集河流水样15个进行分析测试。研究结果表明:(1)桂江河水样品pH值介于6.36~8.46,平均值为7.58;EC范围为18~316μs/cm,平均值为175μs/cm;流域河水SIc平均值为-0.7,其变化受流域碳酸盐岩的分布控制。(2)桂江的水为HCO3-Ca型水,HCO3-和Ca2+平均分别占阴、阳离子的76%和77%,主要来自岩石风化。(3)中游部分河水NO3-和SO42-较高,可能是受工农业等人类活动的影响引起,此外硫酸参与了碳酸盐矿物的溶解。(4)Ca2+、Mg2+和HCO3-总体呈现中游高,上游和下游较低;SO42-和NO3-仅在中游部分受到人类活动影响较多的支流偏高,上下游相对较低且相差不大;Cl-、Na+和K+则呈现出中下游较高,上游较低的特征。   相似文献   

7.
利用稳定同位素识别黑河流域地上水的补给来源   总被引：7，自引：0，他引：7  
本文利用稳定同位素(2H和18O)及水化学方法识别黑河流域地下水的补给来源,估算黑河水与地下水的转化数量。研究结果表明,黑河流域地下水的主要补给来自山区出山河流,山前戈壁带是地下水快速补给区,中下游盆地地下水补给来源为引河灌溉和河流侧渗。黑河干流出山河水在张掖以上河段约4.4×108m3/a渗漏补给地下水,约占出山迳流量的27%。张掖—正义峡河段道地下水向河道平均排泄量为11.4×108m3/a,占该段河流迳流量的69%。研究成果不仅对黑河流域地下水的开发管理有着重要意义,对我国西北类似的内陆盆地地下水的开发管理有着借鉴意义。  相似文献   

8.
为了掌握亚热带季风气候岩溶地区流域水化学变化特征及量化流域内岩石化学风化过程对吸收大气CO2的贡献,文章选取湘西峒河流域作为研究对象,于2016年7—8月对研究区干流和7个子流域进行了水样采集与分析。结果表明:河水pH平均值为8.31,总体呈偏碱性。EC与TDS的变化范围较大,这主要与流域内岩性的分布有关。水中离子以Ca2+、HCO-3为主,水化学类型为HCO3—Ca型,岩性控制水化学的组成。HCO-3、Ca2+和Mg2+主要来源于碳酸盐岩的风化,其余离子来源多受人为活动影响。峒河流域干流的主要离子中,HCO-3、Ca2+和Mg2+浓度从上游至下游总体下降,反映了河流从碳酸盐岩区流向碎屑岩为主地层的过程。NO-3、K+、Na+、F-、Cl-和SO2-4呈增长趋势,说明峒河受人为污染影响较大,反映出人为活动的密集程度。通过子流域的划分可知流域上游主要受灰岩以及白云岩控制,中游以灰岩控制为主,下游受砂岩、泥岩及碎屑岩控制为主。收集流域最终出口吉首观测站一个水文年的数据并运用水化学—径流法估算出峒河流域无机碳通量为60 477.33 tCO2/a,碳汇强度为71.15 tCO2/（km2·a）。  相似文献   

9.
典型岩溶槽谷区地下水化学特征及地球化学敏感性分析   总被引：11，自引：8，他引：3  
利用2012年4月—2013年3月的水化学数据研究了重庆老龙洞地下河流域地下水系统地球化学敏感性。结果表明,研究区表层岩溶泉和地下河水化学阳离子分别以Ca2+、Mg2+和Ca2+、Na+为主,阴离子以HCO3-、SO42-为主;表层岩溶泉雨季Mg2+/ Ca2+摩尔比和地下河雨季Na+/ Ca2+摩尔比旱季大于雨季,表层岩溶泉和地下河雨季 HCO3-/SO42- 摩尔比分别为3.428～6.524、3.122～5.966,旱季HCO3-/SO42-摩尔比分别为5.693～8.664、3.428～6.524,表现出低SO42-、高HCO3-的特征,主要受农业活动影响的表层岩溶泉主量元素地球化学敏感性依次为HCO3-> SO42->Ca2+> NO3-> Mg2+> Na+> K+>Cl-,而受农业活动、工业活动、城镇建设活动等多种因子共同影响下的地下河主量元素地球化学敏感性有所变化,依次为HCO3->Na+> Ca2+> K+> Cl-> Mg2+> NO3-> SO42-,随着人类影响的加剧,离子敏感指数将会有增加的趋势。   相似文献   

10.
天山南坡的萨雷扎兹-库玛拉克河流域在中国阿克苏河协合拉水文站以上面积为12816km2,发育有冰川3195.41km2,冰川覆盖率25%.根据1957—2006年流域站点观测的降水、气温及其径流资料,通过最大熵方法计算了流域冰川物质平衡的逐年变化.结果表明:流域冰川径流深约为895mm,全流域河川径流深为381.3mm,冰川融水占协合拉站控制流量的58.65%,冰川融水变化对流域水资源量的影响非常明显.1957—2006年平均年径流量为48.64×108m3,径流在1993年后急剧增加,1994—2006年的平均年径流量比1957—1993年的增加了10.56×108m3,即增加了23%.由于负物质平衡消耗了大量过去积累的冰川冰,冰川融化对河流额外补给.初步计算,在过去50a由于气温升高引起的冰川净消融额外补给河流的径流量达309.47×108m3,相当于每年径流增加达6.19×108m3,约为年径流量的13%.1957—1993年流域冰川消融对河流的额外净补给量为5.3×108m3,占河流总径流量的11%;1994—2006年流域冰川消融对河流的额外净补给量为8.8×108m3,占河流总径流量的18%.随着...  相似文献   

11.
Analyses of 72 samples from Upper Panjhara basin in the northern part of Deccan Plateau, India, indicate that geochemical incongruity of groundwater is largely a function of mineral composition of the basaltic lithology. Higher proportion of alkaline earth elements to total cations and HCO3>Cl + SO4 reflect weathering of primary silicates as chief source of ions. Inputs of Cl, SO4, and NO3 are related to rainfall and localized anthropogenic factors. Groundwater from recharge area representing Ca + Mg–HCO3 type progressively evolves to Ca + Na–HCO3 and Na–Ca–HCO3 class along flow direction replicates the role of cation exchange and precipitation processes. While the post-monsoon chemistry is controlled by silicate mineral dissolution + cation exchange reactions, pre-monsoon variability is attributable chiefly to precipitation reactions + anthropogenic factors. Positive correlations between Mg vs HCO3 and Ca + Mg vs HCO3 supports selective dissolution of olivine and pyroxene as dominant process in post-monsoon followed by dissolution of plagioclase feldspar and secondary carbonates. The pre-monsoon data however, points toward the dissolution of plagioclase and precipitation of CaCO3 supported by improved correlation coefficients between Na + Ca vs HCO3 and negative correlation of Ca vs HCO3, respectively. It is proposed that the eccentricity in the composition of groundwater from the Panjhara basin is a function of selective dissolution of olivine > pyroxene followed by plagioclase feldspar. The data suggest siallitization (L < R and R k) as dominant mechanism of chemical weathering of basalts, stimulating monosiallitic (kaolinite) and bisiallitic (montmorillonite) products. The chemical denudation rates for Panjhara basin worked out separately for the ground and surface water component range from 6.98 to 36.65 tons/km2/yr, respectively. The values of the CO2 consumption rates range between 0.18 × 106 mol//km2/yr (groundwater) and 0.9 × 106 mol/km2/yr (surface water), which indicates that the groundwater forms a considerable fraction of CO2 consumption, an inference, that is, not taken into contemplation in most of the studies.  相似文献   

12.
Cosmogenic nuclide-based denudation rates and published erosion rates from recent river gauging in the Napo River basin (Peruvian Amazonia) are used to decipher erosion and sedimentation processes along a 600 km long transect from the headwaters to the lowlands. The sediment-producing headwaters to the Napo floodplain are the volcanically active Ecuadorian Andes, which discharge sediment at a cosmogenic nuclide-based denudation rate of 0.49 ± 0.12 mm/yr. This denudation rate was calculated from an average 10Be nuclide concentration of 2.2 ± 0.5 × 104 at/g(Qz) that was measured in bedload-derived quartz. Within the Napo lowlands, a significant drop in trunk stream 10Be nuclide concentrations relative to the Andean hinterland is recorded, with an average concentration of 1.2 ± 0.5 × 104 at/g(Qz). This nuclide concentration represents a mixture between the 10Be nuclide concentration of eroded floodplain deposits, and that of sediment eroded from the Andean hinterland that is now carried in the trunk stream. Evidence for addition of sediment from the floodplain to the trunk stream is provided by published decadal-scale sediment flux measurements from gauging stations operated in the Napo basin, from which an increase from 12 × 106 t/yr at the outflow of the Andes to ～47 × 106 t/yr at the confluence with the Solimões (upper Amazon River) is recorded. Therefore, approximately 35 × 106 t of floodplain sediment are added annually to the active Napo trunk stream. Combined with our nuclide concentration measurements, we can estimate that the eroded floodplain deposits yield a nuclide concentration of ～0.9 × 104 at/g(Qz) only. Under steady state surface erosion conditions, this nuclide concentration would translate to a denudation rate of the floodplain of ～0.47 mm/yr. However, we have no geomorphologic explanation for this high denudation rate within the low relief floodplain and thus suggest that this low-nuclide concentrated sediment is Andean-derived and would have been deposited in the floodplain at a time when erosion rates of the Andes were elevated. Therefore, the recently eroded floodplain sediment provides an Andean “paleo denudation rate” of 1.2 mm/yr that was calculated for high Andean production rates. A likely period for elevated erosion rates is the LGM, where climate and vegetation cover of the Andes differed from that of the Holocene. A possible cause for the erosion of the floodplain is the tectonic uplift of the Eastern Andes, which progressively shifts the Napo River northwards. Hence, the river cuts into ancient lowland sediment, which is admixed to the Andean sediment carried in the main Napo River.  相似文献   

13.
《Applied Geochemistry》2000,15(1):67-77
Discharge is the dominant control on the TDS load of the Bow River; TDS varies inversely with discharge. Although discharge is the dominant control on concentration, the sources of ions in the river are atmospheric deposition and water/rock interaction. Atmospheric loading can be a significant source of some ions in the pristine headwaters of the river (e.g., 50% of K, 17% of SO4, 16% of Cl). In terms of water/rock interaction, the input of ions to the river is largely controlled by dissolution of carbonate and evaporite minerals.The chemical denudation rate for the Bow River at Banff is 678 kg/ha/a, or 1.50×108 kg of rock that is removed as dissolved load each year, in the low range for an alpine carbonate basin. An additional 11 kg/ha/a are removed as suspended load. A rock volume of 5.45×104 m3 is carried by the Bow River from Banff National Park each year.  相似文献   

14.
The Hanjiang River, the largest tributaries of the Changjiang (Yangtze) River, is the water source area of the Middle Route of China’s South-to-North Water Transfer Project. The chemical and strontium isotopic compositions of the river waters are determined with the main purpose of understanding the contribution of chemical weathering processes and anthropogenic inputs on river solutes, as well as the associated CO2 consumption in the carbonate-dominated basin. The major ion compositions of the Hanjiang River waters are characterized by the dominance of Ca2+ and HCO3 −, followed by Mg2+ and SO4 2−. The increase in TDS and major anions (Cl−, NO3 −, and SO4 2−) concentrations from upstream to downstream is ascribed to both extensive influences from agriculture and domestic activities over the Hanjiang basin. The chemical and Sr isotopic analyses indicate that three major weathering sources (dolomite, limestone, and silicates) contribute to the total dissolved loads. The contributions of the different end-members to the dissolved load are calculated with the mass balance approach. The calculated results show that the dissolved load is dominated by carbonates weathering, the contribution of which accounts for about 79.4% for the Hanjiang River. The silicate weathering and anthropogenic contributions are approximately 12.3 and 6.87%, respectively. The total TDS fluxes from chemical weathering calculated for the water source area (the upper Hanjiang basin) and the whole Hanjiang basin are approximately 3.8 × 106 and 6.1 × 106 ton/year, respectively. The total chemical weathering (carbonate and silicate) rate for the Hanjiang basin is approximately 38.5 ton/km2/year or 18.6 mm/k year, which is higher than global mean values. The fluxes of CO2 consumption by carbonate and silicate weathering are estimated to be 56.4 × 109 and 12.9 × 109 mol/year, respectively.  相似文献   

15.
A systematic study of the major ion chemistry of the Ganga source waters—the Bhagirathi, Alaknanda and their tributaries—has been carried out to assess the chemical weathering processes in the high altitude Himalaya. Among major ions, Ca, Mg, HCO3 and SO4 are the most abundant in these river waters. These results suggest that weathering of carbonate rocks by carbonic and sulphuric acids dominates in these drainage basins. On an average, silicate weathering can contribute up to ∼ 30% of the total cations. The concentration of total dissolved salts in the Bhagirathi and the Alaknanda is 104 and 115mg/l, respectively. The chemical denudation rate in the drainage basins of the Bhagirathi and the Alaknanda is, respectively, 110 and 137 tons/km2/yr, significantly higher than that derived for the entire Ganga basin, indicating intense chemical erosion of the Himalaya.  相似文献   

16.
Groundwater is a finite resource that is threatened by pollution all over the world. Shimabara City, Nagasaki, Japan, uses groundwater for its main water supply. During recent years, the city has experienced severe nitrate pollution in its groundwater. For better understanding of origin and impact of the pollution, chemical effects and surface–groundwater interactions need to be examined. For this purpose, we developed a methodology that builds on joint geochemical analyses and advanced statistical treatment. Water samples were collected at 42 sampling points in Shimabara including a part of Unzen City. Spatial distribution of water chemistry constituents was assessed by describing Stiff and Piper diagrams using major ions concentrations. The nitrate (NO3?+?NO2–N) concentration in 45% of water samples exceeded permissible Japanese drinking level of 10 mg L??1. Most of the samples showed Ca–HCO3 or Ca–(NO3?+?SO4) water types. Some samples were classified into characteristic water types such as Na–Cl, (Na?+?K)–HCO3, (Na?+?K)–(SO4?+?NO3), and Ca–Cl. Thus, results indicated salt water intrusion from the sea and anthropogenic pollution. At the upstream of Nishi River, although water chemistry was characterized as Ca–HCO3, ion concentrations were higher than those of other rivers. This is probably an effect of disinfection in livestock farming using slaked lime. Positive correlation between NO3? and SO42?, Mg2+, Ca2+, Na+, K+, and Cl? (r?=?0.32–0.64) is evidence that nitrate pollution sources are chemical fertilizers and livestock waste. Principal component analysis showed that chemistry of water samples can be explained by three main components (PCs). PC1 depicts general ion concentration. PC2 and PC3 share influence from chemical fertilizer and livestock waste. Cluster analyses grouped water samples into four main clusters. One of these is the general river chemistry mainly affected by PC1. The others reflect anthropogenic activities and are identified by the combination of the three PCs.  相似文献   

17.
The combined geothermal discharge from over 10,000 features in Yellowstone National Park (YNP) can be can be estimated from the Cl flux in the Madison, Yellowstone, Falls, and Snake Rivers. Over the last 30 years, the Cl flux in YNP Rivers has been calculated using discharge measurements and Cl concentrations determined in discrete water samples and it has been determined that approximately 12% of the Cl flux exiting YNP is from the Snake River. The relationship between electrical conductivity and concentrations of Cl and other geothermal solutes was quantified at a monitoring site located downstream from the thermal inputs in the Snake River. Beginning in 2012, continuous (15 min) electrical conductivity measurements have been made at the monitoring site. Combining continuous electrical conductivity and discharge data, the Cl and other geothermal solute fluxes were determined. The 2013–2015 Cl fluxes (5.3–5.8 kt/yr) determined using electrical conductivity are comparable to historical data. In addition, synoptic water samples and discharge data were obtained from sites along the Snake River under low-flow conditions of September 2014. The synoptic water study extended 17 km upstream from the monitoring site. Surface inflows were sampled to identify sources and to quantify solute loading. The Lewis River was the primary source of Cl, Na, K, Cl, SiO2, Rb, and As loads (50–80%) in the Snake River. The largest source of SO4 was from the upper Snake River (50%). Most of the Ca and Mg (50–55%) originate from the Snake Hot Springs. Chloride, Ca, Mg, Na, K, SiO2, F, HCO3, SO4, B, Li, Rb, and As behave conservatively in the Snake River, and therefore correlate well with conductivity (R2 ≥ 0.97).  相似文献   

18.
The isotopic composition of dissolved boron, in combination with the elemental concentrations of B, Cl and salinities in freshwater-seawater mixed samples taken from the estuary of the Changjiang River, the largest one in China, was investigated in detail in this study. Brackish water and seawater samples from the estuary of the Changjiang River were collected during low water season in November, 1998. Boron isotopic compositions were determined by the Cs2BO^＋2-graphite technique with a analytical uncertainty of 0.2‰ for NIST SRM 951 and an average analytical uncertainty of 0.8‰ for the samples. The isotopic compositions of boron, expressed in δ^11B, and boron concentrations in the Changjiang River at Nanjing and seawater from the open marine East Sea, China, are characterized by δ^11B values of -5.4‰ and 40.0‰, as well as 0.0272 and 4.43 mg B/L, respectively. Well-defined correlations between δ^11B values, B concentrations and Cl concentrations are interpreted in terms of binary mixing between fiver input water and East Sea seawater by a process of straightforward dilution. The offsets of δ^11B values are not related to the contents of clastic sediment and to the addition of boron. These relationships favor a conservative behavior of boron at the estuarine of the Changjiang River.  相似文献   

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