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1.
【研究目的】为查明长春新区地下水特征及演化，支撑东北老工业基地建设。【研究方法】本文在调查取样的基础上，充分利用前人成果资料，应用SPSS分析软件、地下水污染分析软件，通过对长春新区的地质条件、水化学参数空间分布特征、地下水化学类型、地下水化学成因的分析，得出系列结果。【研究结果】长春新区地下水的硬度较高且矿化度较大，HCO3－在地下水的离子中占据主导，Ca2+、Cl-、O42-、Na+在地下水中的绝对质量浓度较高；pH、H2SiO3、Sr、TDS、Mg2+、HCO3－的质量浓度相对稳定；地下水离子以HCO3－和Ca2+为主；Na+和K+同时来自岩盐和硅酸岩的溶解；Ca2+和Mg2+主要来源于碳酸盐的溶解。区内地下水质量可分为四级，其中Ⅴ类水未评出。【结论】总体来看，Ⅰ类水占7.50%，Ⅱ类水占32.10%，Ⅲ类水占20.80%，Ⅳ类水占39.60%。较好以上地下水占60.4%，总体情况较好。创新点：研究了国家级新区的地下水化学、成因和演化，得出地下水的水质特征，有效支撑区域生态健康发展。 相似文献
2.
广东省顺德肝癌多发区病因探讨 总被引：3，自引：0，他引：3
根据顺德肝癌病多发区与周边正常区土壤、水地球化学特征对比,结合病区人文景观探讨顺德肝癌病因,分析认为病区水中NH4+, NO2-, NO3-的显著异常(高含量)是主要病因。 相似文献
3.
为了研究祁连山大雪山地区大气PM2.5细粒子中可溶性无机离子组分的变化特征, 于2010年7月至2011年7月在祁连山冰川与生态环境综合观测站附近采集46个大气PM2.5的Telfon滤膜样品, 并应用离子色谱对可溶性离子进行了分析.结果显示: 所测样品的阴、 阳离子中, SO42-、 NO-3、 Ca2+和NH+4的质量浓度分别为1.54μg·m-3、 0.38μg·m-3、 0.73μg·m-3和0.22μg·m-3, 累计约占到水溶性离子总量的88%.可溶性离子浓度呈现出春夏季节明显高于秋冬季节的特征, 夏季的浓度最高, 其次是春季、 冬季和秋季. Cl-、 Ca2+、 Na+和Mg2+之间的相关性极高, SO42-和NO-3与大部分阳离子的相关性都很高, 说明大部分硫酸盐是来自于中亚沙尘源区的自然源, 而并非是通过人类活动造成的一次污染物通过二次反应过程得到的. NH+4仅与SO42-通过相关性检验说明, 该地区NH3主要中和了大气中硫酸并生成(NH4)2SO4.该地区的大气环境主要来源于自然源的影响, 但夏季风期间人为污染排放已经不可忽视, 这也得到HYSPLIT后向轨迹模式的计算验证. 相似文献
4.
提要：汤泉位于河北省遵化市西北部,为山前丘陵地貌,地热资源丰富。本文通过对该地区地热流体研究发现：Na+、Ca2+、K+、Mg2+与SO2-4、HCO-3、Cl-、NO-3是该地区地下热水的主要成分,水化学类型主要为SO2-4-Na+型,属于未污染的天然弱碱性水;流体中F-含量平均为9.36 mg/l,远高于国家地下水质量标准ⅴ级;可溶性SiO2的含量可作为地热温标;地热流体总矿化度平均为782.33 mg/l,属于淡水;为中等腐蚀型水,不结碳酸钙垢,无CaSO4?2H2O垢和SiO2垢生成的可能;地热流体属于含岩盐地层溶滤的陆相沉积水;根据氢氧稳定同位素可知,河北汤泉地热流体主要来源于大气降水。 相似文献
5.
【研究目的】 为查明浙江宁波平原地下水特征及成因演化,促进宁波地区地下水环境优化。【研究方法】 在野外调查和取样分析的基础上,充分利用前人资料,综合运用数理统计、相关性分析、Piper三线图、离子比例系数及环境同位素等方法手段,全面系统地分析了宁波平原地下水状况。【研究结果】 宁波平原地表水和潜水以淡水为主,Ⅰ承压水和Ⅱ承压水以微咸水、咸水为主,潜水中HCO3-占绝对优势,Cl-、Ca2+、Na+次之,地表水和承压水中Cl-、Na+占主导地位,HCO3-次之。4种水共划分23种水化学类型,地表水和潜水受大气降水影响明显,深层承压水以封存型为主,与浅表水体天然联系不密切,受地质历史时期海侵影响较大。【结论】 与20世纪70年代相比,宁波城区Ⅰ承压淡水体分布范围无明显变化,Ⅱ承压水在人类生产生活和水体自然循环双重影响下,原淡水区演化出孤岛状咸水体,但淡水体整体分布范围外扩,面积增加了约12 km2,其生态环境效应趋于正向发展。 相似文献
6.
临安一次沙尘暴过程影响气溶胶物理化学特性演变的初步分析 总被引：16，自引：4，他引：12
文章利用2002年3月29日～4月4日在浙江临安大气本底污染监测站观测的气溶胶粒子质量谱、离子与元素成分的数据,结合TOMS卫星的气溶胶指数资料和轨迹模式,重点分析在北方沙尘暴输送影响期间临安气溶胶质量浓度尺度分布的演变特点以及气溶胶化学成分与不同空气来源的关系。初步分析结果显示,受北方沙尘暴天气影响,临安气溶胶质量浓度、离子、元素浓度有明显的尺度分布演变。这种演变与污染物来源和大气污染物的气粒转化有关。沙尘影响前和结束后临安地区气溶胶主要以细粒子为主(<2.1μm),峰值粒径0.65～2.1μm,而受北方地区的沙尘暴影响,峰值粒径偏移到2.1～3.3μm,且在7～11μm间出现另一个峰值,同时临安气溶胶粗粒子中矿物元素显著增加。从离子成分看,在整个观测期间SO2-4与NH+4在细粒子段有很好的一致性,而SO2-4,NO-3与Ca2+在粗粒子段有很好的相关,尤其是沙尘影响期间NO-3与Ca2+有很好的对应关系,表现出较明显的表面非均相反应特征 相似文献
7.
为了研究泉水化学成分特点和在一年内的变化,文章利用pH-电导率自动记录仪对陕西秦岭翠华山地区两处泉水化学成分进行了每月2次的观测,并进行了水化学分析。翠华山泉水中HCO-3含量在76.27～152.55mg/L之间,Ca2+含量在14.48～26.92mg/L之间,Mg2+含量在4.46～4.89mg/L之间,K+含量在0.60～2.75mg/L之间,Na+含量在0.93～1.09mg/L之间,这些成分的特点是含量低。泉水pH值在6.98～5.69之间,夏秋季低于该区雨水的pH值,具酸性特征,这是该区地层主要由片麻岩构成决定的。从1月到11月,水秋池村泉水pH值和电导率呈现由大到小再到大的变化规律,引起这种变化的主要原因是夏秋季土壤CO2含量比冬春季高,泉水在夏秋季流动过程中吸收了较多的CO2。翠华湖西泉水pH值和Ca2+,Mg2+,K+,Na+离子含量比水秋池泉水高,从1月到11月Ca2+,Mg2+,K+,Na+离子含量变化与水秋池泉水变化相反,这应当是两个泉水的来源不同或在流动过程中遇到了酸碱性不同的土层和地层造成的。翠华山地区泉水化学成分变化是易于观测到的规律性很强的变化。 相似文献
8.
新疆东天山土屋斑岩铜矿床流体包裹体地球化学特征 总被引：10，自引：1，他引：9
本文在系统总结前人关于土屋矿床地质特征及成矿作用的基础上,开展了氢氧同位素研究及石英流体包裹体均一法和冷冻法测温,并对石英样品进行了气相及离子色谱测量,对石英中流体包裹体中的稀土元素进行了测试。结果表明,流体包裹体均一温度变化于125~363℃,主要集中于140~200℃,盐度变化于0.18%~58.28%NaCl,主要集中于2%~10% NaCl。流体包裹体气相的主要成分为H2O和CO2,液相成分以Ca2+、Na+、SO2-4、Cl-为主。石英流体包裹体中∑REE 为8.07×10-6~ 12.15×10-6,轻、重稀土之比值（LREE/HREE）变化于5.39~6.75,δEu为1.80~1.91。流体包裹体中稀土元素配分型式呈右倾型,并表现出Eu的正异常及Ce的负异常。石英中流体包裹体的δDV-SMOW值为-70‰~-66‰,石英的δ18OV-SMOW为9.4‰~12.3‰,计算所得的δ18O水为-5.1‰~-1.2‰。根据离子色谱分析结果,F-/Cl-介于0.009~0.024之间,SO2-4/Cl-介于0.45~1.01之间。综合以上流体包裹体的组成和特征,表明成矿流体可能主要来源于岩浆水和大气降水。 相似文献
9.
早子沟金矿地处夏河—合作—岷县区域性深大断裂带南侧,在时空上受断裂和壳幔混合岩浆双重控制。通过对矿床主要控矿因素、矿石稀土地球化学、流体包裹体及S、H、O、Pb同位素的系统研究,在探讨成矿流体来源的基础上,对地幔流体参与金矿成矿作用的可能性进行了探讨。研究表明：矿石稀土元素配分模式表现出轻稀土富集的特征;矿床流体包裹体气相成分主要为H2O和CO2,含少量CH4、N2等,液相成分阳离子以Na+、K+为主,含少量Ca2+ 、Mg2+,阴离子以SO42-、Cl-为主;黄铁矿、辉锑矿矿物的?啄34 Sv-CDT介于-10. 30‰ ~ -4. 9‰之间,平均-8. 33‰,反映成矿作用过程有地层硫的加入;氢、氧同位素显示成矿流体既有岩浆水和地幔初生水的参与,亦有大气降水的加入;矿石铅同位素组成显示铅来源于壳幔的混合。以上说明成矿流体具多源性,暗示地幔流体参与了矿床成矿作用。 相似文献
10.
【研究目的】 了解长江中下游平原地区地下水流系统并深入分析其地下水水化学特征及其演化机制。【研究方法】 综合马鞍山市当涂地区的水文地质条件、水动力场等,基于研究区水化学基本特征,运用多元统计分析、水化学图件、离子比值和反向水文地球化学模拟等方法对该地区浅层地下水水化学演化进行分析。【研究结果】 结果表明：（1）研究区地下水主要为低矿化度偏碱性水,地下水组分中阳离子以Ca2+和Mg2+为主,阴离子以HCO3-和SO42-为主。（2）研究区地下水水化学类型主要可分为7类,其中松散岩类孔隙含水岩组和碎屑岩类孔隙裂隙含水岩组的水化学类型主要为HCO3-Ca型、HCO3-Ca·Na型、HCO3·Cl-Ca·Na型以及HCO3-Ca·Mg型;基岩类裂隙含水岩组的化学类型主要为HCO3·SO4-Ca·Mg型和SO4·HCO3-Ca·Mg型。（3）研究区浅层地下水水样超标率为46%,总体水质较差,超标率较高的组分依次为Mn、高锰酸盐指数（CODMn）、硝酸盐（以N计）、Fe、As、氨氮（以N计）等。（4）研究区地下水的化学组分主要受到岩石风化作用的控制;此外,还存在Na-Ca的正向阳离子交替吸附作用。反向水文地球化学模拟结果进一步定量论证了水岩相互作用对本区浅层地下水组分的形成和演化起着主导作用。【结论】 研究区地下水主要为低矿化度偏碱性,主要可分为松散岩类孔隙水、碎屑岩类孔隙裂隙水和基岩类裂隙水。主要离子比例和反向水文地球化学模拟揭示了本区浅层地下水化学组分主要是地下水溶滤方解石、白云石等碳酸盐矿物、石英、长石等硅酸盐矿物,高岭土等黏土矿物以及岩盐、石膏等达到过饱和之后形成的。 相似文献
11.
为了解喀斯特地区水-岩相互作用特征和辨别地下水污染物的来源,为揭示人类活动对喀斯特地下水文地球化学环境的影响,研究了贵州省贵阳市不同岩性含水层地下水和地表水的化学特征.结果发现,地表和地下水主要有HCO3型和SO4型以及这两种化学类型的混合型.地下水地表水化学溶解物质主要来源于碳酸盐岩和碎屑沉积岩的化学风化作用,硫酸盐矿物的溶解和硫化物氧化形成的硫酸对岩石矿物的化学风化是导致水体富集硫酸盐的主要因素.区内地表水和地下水的主要污染物质为K+、Na+、Cl-、SO42-和NO3-.这一研究成果为评价地表/地下水环境的质量现状,为喀斯特地区地表水地下水资源的保护和利用提供了科学依据. 相似文献
12.
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
13.
Strontium as a tracer of weathering processes in a silicate catchment polluted by acid atmospheric inputs, Strengbach, France 总被引：4，自引：0，他引：4
This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio 87Sr/86Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The 87Sr/86Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified. 相似文献
14.
贵州喀斯特地区河流的研究--碳酸盐岩溶解控制的水文地球化学特征 总被引：41，自引：1，他引：40
测量了喀斯特地区乌江、沅江两大水系的河流枯水期的主元素、Sr2+离子浓度和Sr同位素比值。这些河流的化学组成代表了流经碳酸盐岩地层的河水的化学组成。这些河流及其支流有高的溶解盐,TZ+变化范围为：2.1～6.3 meq/L,高于全球河流的平均值(TZ+=0.725 meq/L)。河水含有较高的溶质浓度,河水水化学组成以Ca2+和HCO-3为主,其次为Mg2+和SO2-4,Na++K+和Cl-+Si分别只占阳离子和阴离子组成的5%～10%。
这些河流的化学和同位素组成主要受其自流盆地的地质特征控制。流经碳酸盐岩地层的乌江水系河流具有较高的Sr浓度（1.1～9.70 mol/L）和较低的87Sr/86Sr比值（0.7077～0.7110）,与流经碎屑岩地层的沅江水系的清水江河流中较高的87Sr/86Sr比值（0.7090～0.7145）及较低的Sr浓度（0.28～1.32 mol/L）形成鲜明的对比。
流域盆地的地理岩性控制了河水的化学组成和同位素组成。对河水的化学计量分析表明河水化学组成受碳酸盐岩溶解控制,而碳酸盐岩主要受碳酸和硫酸作用而溶解。乌江流域受硫酸作用特别明显,表明硫酸主要来源于燃煤或流域盆地硫化物矿物氧化而形成的大气输入。化学元素和同位素比值之间的相互关系表明3个主要来源为：石灰岩、白云岩和硅酸盐岩的风化。同时估计了碳酸盐岩和硅酸盐岩的化学风化速率,结果表明流域盆地的碳酸盐岩风化速率远远高于许多世界大河。岩石风化过程中硫酸的出现或土地的过度使用或土壤植被的退化等都可能是导致流域的碳酸盐岩风化速率如此高的原因。 相似文献
15.
Strontium concentrations of 253 natural water samples from Skagafjördur, a Tertiary tholeiitic flood basalt region in northern Iceland range between 0.10 and 28 ppb. Surface environments (rivers, lakes, and peat soil waters) include the whole range of observed Sr concentrations whereas the Sr concentrations of ground waters are, in most cases, <3.5 ppb. Concentrations of Sr derived from basalt dissolution (i.e., rock-derived Sr) in waters of rivers and lakes exhibit a near linear correlation with the concentration of rock-derived Ca with a median molar Ca/Sr ratio of 1350. This systematic correlation suggests that Ca and Sr concentrations are controlled by weathering processes, i.e., the extent of dissolution of the basalt. The relative mobility of Sr during weathering in Skagafjördur is approximately half that of Ca, which is consistent with observed relative mobilities of these elements elsewhere in Iceland and in other basaltic regions. Peat soil waters commonly have lower concentrations of Sr and higher Ca concentrations than rivers and lakes, and molar ratios of rock-derived Ca to Sr in peat soil waters exhibit no systematic pattern. In several cases calculated concentrations of rock-derived Sr in peat soil waters yield negative values, suggesting a mineralogic sink for Sr in these waters.The low Sr concentrations in cold and thermal ground waters (<3.5 ppb) suggest mineralogic control over Sr in the ground water systems. Precipitation of secondary Sr minerals such as strontianite and celestite is ruled out as the ground waters are understaturated with respect to these minerals. Ground waters are characterized by high Ca/Sr molar ratios (∼5000 compared to bedrock Ca/Sr ratio of 730) suggesting that Sr is being preferentially incorporated (relative to Ca) into secondary minerals. The secondary minerals present in the bedrock in Skagafjördur that can preferentially incorporate Sr include zeolites, such as heulandite, chabazite, and thomsonite, and smectite. Ion-exchange calculations demonstrate that activities of Sr2+ and Ca2+ in ground water solutions in Skagafjördur are consistent with ion-exchange equilibria between these waters and heulandite from other Tertiary basalts in Iceland suggesting that this mineral may play an important role in controlling the concentration of Sr in the Skagafjördur ground waters. Incorporation of Sr into calcite cannot explain the observed high Ca/Sr ratios of the Skagafjördur ground waters because calcite, when precipitating, only admits limited amounts of Sr. Aragonite is not considered a likely candidate either because it has only very slight preference for Sr over Ca and ground waters above 40 °C are undersaturated with respect to this phase. However, predicted Sr content of calcite in equilibrium with the Skagafjördur ground waters (0.5-83 ppm Sr) is in good agreement with measured Sr content of this mineral in Tertiary basalts elsewhere in Iceland (<0.1-63 ppm), suggesting that the Skagafjördur ground waters can be used as analogues for Tertiary crustal solutions involved in the zeolite facies metamorphism of the Icelandic crust. 相似文献
16.
贵阳地表水—地下水的硫和氯同位素组成特征及其污染物示踪意义 总被引：5，自引：0，他引：5
喀斯特地表水和地下水的交换活跃,地下水系统容易受到地表污染物的污染。为了解喀斯特城市地表水—地下水系统污染特征和污染物质来源,对贵阳市地表水、地下水、雨水和城市排污污水的硫同位素和氯同位素组成变化进行了研究。贵阳市不同类型水体的δ37Cl值在-4.07‰～+2.03‰之间变化,δ34SSO4值变化为-20.4‰～+20.9‰。大气输入物质和城市排污污水的δ37Cl、δ34S及Cl-/SO42-比值与地表水和地下水的不同,稳定硫和氯同位素的结合研究为示踪地下水污染物来源提供了有效研究手段。贵阳市地下水中的Cl-和SO42-至少有4种来源,人为活动通过城市排污和大气输入向地下水系统大量输入了硫酸盐和氯离子。 相似文献
17.
Isotopic Composition of Waters in the Dem?novská dolina Valley and Its Underground Hydrologic System During Winter and Spring of 2010/2011 
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下载免费PDF全文 In the Dem?novská dolina Cave system (Slovakia) and its vicinity, 32 sampling places for regular observation (in 2-months interval) of δ18O and δ2H in water were established. This monitoring included precipitation waters, waters in the surface streams, waters of the underground hydrological system as well as the dripping seepage waters of the cave system. Altitudinal extent of the area was from 800 m a.s.l. (lowermost cave entrance) to 2024 m a.s.l. (Chopok Mt. on the top of the crystalline range). Initial results show some similarities but also differences within the analyzed water types. For precipitation, a high variability of isotopic composition was confirmed, from quite depleted up to more enriched waters (δ18O from -16.8‰ up to -5.7‰; δ2H from -121.6‰ to -32.7‰). During the recharge process and groundwater/surface water formation, precipitation water is homogenized, what is reflected in much more stable isotope content. The most depleted (δ18O ≈ -11.7‰ to -10.8‰; δ2H ≈ -78.9‰ to -73.4‰) were the waters of surface streams, running from the northern slopes of the Nízke Tatry Mts., formed by crystalline rocks, alochtonous to the under?ground hydrological system. Smaller autochtonous surface water streams (formed in the side valleys of the main karstic canyon) are slightly enriched (heavier, as δ18O ≈ -11.4‰ to -10.6‰; δ2H ≈ -78.3‰ to -71.5‰), what reflects lower altitudes of their watersheds. Interesting is the distribution of the isotope content of the underground streams in the cave system. The most depleted are the underground streams directly (visibly) communicating with surface waters (δ18O≈-11.33±0.13‰; δ2H≈-76.88±1.68‰). Extent of the relationship of underground streams to the autochtonous seepage waters (slow circulation through the fissures) is manifested by respective portion of iso?topically enriched waters–as the underground streams show different isotope composition. The combination of the alochtonous water components (from surface streams reaching the karstic area from the adjacent crystalline via swallow holes) and autochtonous water components (recharged directly in karstified limestones) is visible especially on the subsurface stream of Dem?novka. The most isotopically enriched (heaviest) of all water types are dripping seepage waters (δ18O ≈ -10.4‰ to -9.4‰; δ2H ≈ -71.6‰ to -65.0‰). 相似文献
18.
Taiwan is a typical active orogenic belt situated at the collision boundary between the Eurasian Continental Plate and the Philippine Sea Plate. Dissolved major and trace constituents, as well as Sr and Sr isotopes in river waters collected from the Danshuei River basin in northern Taiwan have been studied to evaluate chemical weathering processes. The results of principal component analysis show that the ion sources in these river waters can be categorized into 3 major components: chemical weathering, seasalt contribution and local anthropogenic input. The chemical weathering is the most dominant factor that contributes about 85% of total variances. Significantly increased Na/Cl and Ca/Cl, as well 87Sr/86Sr, were observed in most upper stream samples. The Na/Cl and Ca/Cl ratios in the Dahan Stream, however, are much higher than the Shindien Stream. Even though average rainfall is stronger in the Shindien drainage basin, chemical evidence from river waters supports less intense weathering in the region. Selective dissolution of secondary calcites explains the observed high Ca/Cl, Sr/Cl and Ca/Na in the Dahan Stream. These results highlight the potential importance of tectonic factors, such as uplift and physical erosion in studying chemical weathering in an active orogenic belt. 相似文献
19.
地壳风化系统中的Sr同位素地球化学 总被引：10，自引：0，他引：10
近20年来,人们利用Rb－Sr同位素体系对地表－近地表地球化学过程、尤其是水圈－岩石圈之间化学物质的循环进行了广泛而深入的研究。大陆地壳风化物质以及地表径流的Sr同位素组成变化揭示了不同流域盆地的地质背景和风化作用的特征。古海洋的Sr同位素组成变化则是地壳和地幔演化以及不同地质历史时期壳－幔相互作用的共同结果。本文对地壳风化系统Sr同位素地球化学研究的全面而详细的综述表明,Rb－Sr同位素体系仍将是研究地壳风化、水圈－岩石圈之间化学物质循环的重要手段,根据古海水及其化学沉积物的Sr同位素记录研究壳－幔演化和地球圈层演化过程中的物质循环特征以及地表古环境变化将是本研究领域的重点。 相似文献
20.
River water composition (major ion and 87Sr/86Sr ratio) was monitored on a monthly basis over a period of three years from a mountainous river (Nethravati River) of southwestern India. The total dissolved solid (TDS) concentration is relatively low (46 mg L−1) with silica being the dominant contributor. The basin is characterised by lower dissolved Sr concentration (avg. 150 nmol L−1), with radiogenic 87Sr/86Sr isotopic ratios (avg. 0.72041 at outlet). The composition of Sr and 87Sr/86Sr and their correlation with silicate derived cations in the river basin reveal that their dominant source is from the radiogenic silicate rock minerals. Their composition in the stream is controlled by a combination of physical and chemical weathering occurring in the basin. The molar ratio of SiO2/Ca and 87Sr/86Sr isotopic ratio show strong seasonal variation in the river water, i.e., low SiO2/Ca ratio with radiogenic isotopes during non-monsoon and higher SiO2/Ca with less radiogenic isotopes during monsoon season. Whereas, the seasonal variation of Rb/Sr ratio in the stream water is not significant suggesting that change in the mineral phase being involved in the weathering reaction could be unlikely for the observed molar SiO2/Ca and 87Sr/86Sr isotope variation in river water. Therefore, the shift in the stream water chemical composition could be attributed to contribution of ground water which is in contact with the bedrock (weathering front) during non-monsoon and weathering of secondary soil minerals in the regolith layer during monsoon. The secondary soil mineral weathering leads to limited silicate cation and enhanced silica fluxes in the Nethravati river basin. 相似文献