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花岗岩地区水-岩反应次生矿物的沉淀饱和指数估算 总被引：1，自引：0，他引：1
水-岩反应次生矿物的沉淀作用不仅控制着地下水成分的演化,而且对核素的迁移和阻滞作用有重要影响。但在常温系统中,矿物的成核生长需要过饱和驱动力的存在,而且不同次生矿物成核生长所需的过饱和度有差异。本文在对日本和加拿大花岗岩地区水-岩系统的地质和地球化学特征进行分析研究的基础上,使用地球化学模拟软件PHREEQC2．15和数据库Ilnl．dat计算了次生矿物在地下水中的饱和指数,从而对各种矿物的沉淀饱和指数进行了估算。结果表明,方解石的化学活动性较强,容易溶解和沉淀,其沉淀饱和指数大约为0．5;针铁矿是地下水中铁的主要沉淀形式,其饱和指数的计算结果与pe值关系密切,沉淀饱和指数高达4．0±0．5;结合高岭石、伊利石、钙蒙脱石和钠蒙脱石之间的相平衡关系,估算其沉淀饱和指数分别为4．0±0．5、4．5±0．5、4．3±0．5和4．3±0．5。 相似文献
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水—岩化学平衡模拟中误差传递及灵敏度分析 总被引：4，自引：0，他引：4
以水－岩化学平衡模型ＷＡＴＥＱ４Ｆ为基础程序,选取平顶山矿区一典型岩溶水点,对固定温度和变化温度两种情况下,水－岩化学平衡模拟输入的水化学分析数据误差传递进行了研究,结果表明,水化学分析数据误差能够强烈地影响水－岩化学平衡模拟结果;不同的水化学变量（误差）对不同的矿物的饱和指数的影响程度不同,在许多情况下,矿物饱和指数误差是随温度变化而变化的。 相似文献
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通过对延河泉域地质、水文地质和水文地球化学分带特征的分析,运用热力学方法计算,确定了碳酸盐岩、硫酸盐岩矿物溶沉方向的反应比率(饱和指数),以此划分了岩溶地下水的环境保护区,并提出了保护措施. 相似文献
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反应条件指数(RCI)和饱和指数(SI)都是建立在热力学基础上说明水中物质溶解与沉淀作用的水文地球化学参数。饱和指数能够客观地反映水文地球化学作用发生的方向和状态,反应条件指数综合了水文地球化学状态条件和水文地球化学作用边界条件的信息,它不仅能反映水文地球化学作用发生的方向和状态,而且可以反映其发生的条件及原因。根据反应条件指数和反应条件边界值的概念,运用热力学基本原理和质量作用定律对反应条件指数与饱和指数的关系进行了论证,结果表明两者呈线性函数关系。这对认识和解决生产、科研中存在的水文地球化学问题具有重要指导意义。 相似文献
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水－岩反应实验研究现状与进展 总被引：3，自引：0，他引：3
水－岩反应实验研究是地学界瞩目的前缘课题之一。开放的流动体系水－岩（矿物）反应动力学实验和水－岩（矿物）界面地球化学及表面特性的研究，是该领域取得的最重要的进展。 相似文献
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稠油热采水岩反应数学模型的应用 总被引：2，自引：0，他引：2
李爱国 《西安地质学院学报》1997,19(3):54-60
稠油热采过程中，由于储层处于高温环境下，注入介质的储层中必将引起强烈的水岩作用，从而导致储层物质发生明显的物理化学变化，根据稠油热采水岩反应数学模型，文中模拟了稠油热采蒸气吞吐井吐出水的水岩反应，通过模拟结果，分析了稠油热采蒸气吞吐过程中，ｐＨ值，组分浓度及各矿物的饱和指标随温度的变化特征，根据饱和指标曲线图分析，模型模拟结果同吐出水固体矿物颗粒电子探针分析结果基本吻合，另外，还对稠油热采水岩反应 相似文献
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平顶山矿区地下热水深部温度估算——地球化学温标的应用 总被引：1，自引：0，他引：1
应用地球化学温标估算了平顶山矿区地下热水的深部温度；介绍与分析了地球化学温标的应用条件、水－岩反应平衡状态，在此基础上应用合适的温标进行了计算。其结果为该区地温场和水－岩温度关系的研究提供了资料 相似文献
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地质流体 岩石反应的地球化学动力学方法 总被引：3，自引：1，他引：2
摘 要 提出了一个以矿物生成和溶解的速率确定体系矿物沉淀的量来模拟水 岩反应的新方
法。新固相在体系中沉淀的量只依赖于沉淀速率而不是依赖于水 岩之间的平衡。考察了一
个矿物溶解生成次生矿物最终趋于平衡的溶解沉淀反应演化结果表明在水 岩体系中对于次
生矿物的部分平衡假定在许多情况下都不能成立。在这样的反应演化过程中亚稳矿物与溶液
之间总保持过饱和态矿物的沉淀速率随反应的进展而变化。同时当主要溶解矿物达到平
衡而溶解作用停止时次生矿物沉淀尚未停止直到体系饱和指数全部趋于0时才达到总
体平衡。用动力学方法处理地球化学过程中的水 岩反应比准稳平衡的简单假设更合理因为
动力学方法更符合自然情况同时产生了关于时间过程的时间尺度信息。 相似文献
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论述了玄武岩的空隙类型及其网络系统、玄武岩水文性质基本特征,分析了玄武岩地下水的富集规律和补径排条件,同时,还对玄武岩地下水资源及其开发利用,以及玄武岩地区广泛分布的饮用天然矿泉水做了简要介绍。 相似文献
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冀北坝上一带玄武岩地区广布富偏硅酸地下水，研究其形成机制及其水岩作用过程对矿泉水的合理开发利用与京津冀水源涵养功能具有重要意义.结合玄武岩地质建造地下水赋存特征，综合利用水化学分析，玄武岩岩石风化机制，水岩相互作用矿物平衡体系，δD、δ18O和δ13C同位素、14C放射性同位素测年等方法，剖析了汉诺坝玄武岩偏硅酸矿泉水形成的岩石地球化学风化和水文地球化学过程及地质建造制约因素.结果表明，研究区矿泉水为低矿化度的HCO3-Ca·Mg型与HCO3-Na·Ca型水，矿泉水形成类型有构造断裂深循环淋溶型和层状补给富集埋藏型2类.上层古风化壳地下水14C校正年龄约为4 050 a，地下水可溶性无机碳来源于土壤CO2与幔源CO2的混合作用.偏硅酸矿泉水的形成与分布受玄武岩地质建造制约，受岩石地球化学特征、岩石风化地表过程和水文地球化学响应过程控制.地下水中偏硅酸主要来源于玄武岩中斜长石、单斜辉石、镁橄榄石等硅酸盐矿物的风化水解；岩石矿物风化的水化学响应过程受溶滤作用控制，受阳离子交换作用影响. 相似文献
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A holistic study of the composition of the basalt groundwaters of the Atherton Tablelands region in Queensland, Australia
was undertaken to elucidate possible mechanisms for the evolution of these very low salinity, silica- and bicarbonate-rich
groundwaters. It is proposed that aluminosilicate mineral weathering is the major contributing process to the overall composition
of the basalt groundwaters. The groundwaters approach equilibrium with respect to the primary minerals with increasing pH
and are mostly in equilibrium with the major secondary minerals (kaolinite and smectite), and other secondary phases such
as goethite, hematite, and gibbsite, which are common accessory minerals in the Atherton basalts. The mineralogy of the basalt
rocks, which has been examined using X-ray diffraction and whole rock geochemistry methods, supports the proposed model for
the hydrogeochemical evolution of these groundwaters: precipitation + CO2 (atmospheric + soil) + pyroxene + feldspars + olivine yields H4SiO4, HCO3
−, Mg2+, Na+, Ca2+ + kaolinite and smectite clays + amorphous or crystalline silica + accessory minerals (hematite, goethite, gibbsite, carbonates,
zeolites, and pyrite). The variations in the mineralogical content of these basalts also provide insights into the controls
on groundwater storage and movement in this aquifer system. The fresh and weathered vesicular basalts are considered to be
important in terms of zones of groundwater occurrence, while the fractures in the massive basalt are important pathways for
groundwater movement. 相似文献
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Deccan basalts of west-central India are hydrogeologically inhomogeneous rocks. A proper understanding of the physical framework of the basalts within which groundwater resides and moves is a key to the hydrogeology of these rocks. Two types of basalt, the vesicular amygdaloidal basalt and the compact basalt, occur as alternate layers in the volcanic pile. Although the rocks are generally inhomogeneous, structures in the basalt, such as sheet joints and vertical joints, serve as zones of groundwater flow. In the shallow subsurface, two groundwater systems are operative. Groundwater system A consists of a vesicular amygdaloidal basalt underlain by a compact basalt, whereas groundwater system B consists of a vesicular amygdaloidal basalt overlain by a compact basalt. Groundwater system A has a better developed network of openings and, as a consequence, this system has a higher transmissivity and storage coefficient than groundwater system B. Wells tapping groundwater system A have higher yields on average and irrigate more hectares of cropland than do wells tapping groundwater system B. This simple systems concept offers a practical methodology for understanding the geometry of the physical framework that contains groundwater in the Deccan basalts. The efficacy of the concept is in its widespread utility for the region. The concept may also be extrapolated to help understand the hydrogeology of deeper Deccan basalt groundwater systems. 相似文献
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The behaviour of Li and Mg isotopes during primary phase dissolution and secondary mineral formation in basalt 总被引：1，自引：0，他引：1
Josh Wimpenny Sigurður R. Gíslason Abdelmouhcine Gannoun Philip A.E. Pogge Von Strandmann 《Geochimica et cosmochimica acta》2010,74(18):5259-6026
This study presents lithium (Li) and magnesium (Mg) isotope data from experiments designed to assess the effects of dissolution of primary phases and the formation of secondary minerals during the weathering of basalt. Basalt glass and olivine dissolution experiments were performed in mixed through-flow reactors under controlled equilibrium conditions, at low pH (2-4) in order to keep solutions undersaturated (i.e. far-from equilibrium) and inhibit the formation of secondary minerals. Combined dissolution-precipitation experiments were performed at high pH (10 and 11) increasing the saturation state of the solutions (moving the system closer to equilibrium) and thereby promoting the formation of secondary minerals.At conditions far from equilibrium saturation state modelling and solution stoichiometry suggest that little secondary mineral formation has occurred. This is supported by the similarity of the dissolution rates of basalt glass and olivine obtained here compared to those of previous experiments. The δ7Li isotope composition of the experimental solution is indistinguishable from that of the initial basalt glass or olivine indicating that little fractionation has occurred. In contrast, the same experimental solutions have light Mg isotope compositions relative to the primary phases, and the solution becomes progressively lighter with time. In the absence of any evidence for secondary mineral formation the most likely explanation for these light Mg isotope compositions is that there has been preferential loss of light Mg during primary phase dissolution.For the experiments undertaken at close to equilibrium conditions the results of saturation state modelling and changes in solution chemistry suggest that secondary mineral formation has occurred. X-ray diffraction (XRD) measurements of the reacted mineral products from these experiments confirm that the principal secondary phase that has formed is chrysotile. Lithium isotope ratios of the experimental fluid become increasingly heavy with time, consistent with previous experimental work and natural data indicating that 6Li is preferentially incorporated into secondary minerals, leaving the solution enriched in 7Li. The behaviour of Mg isotopes is different from that anticipated or observed in natural systems. Similar to the far from equilibrium experiments initially light Mg is lost during olivine dissolution, but with time the δ26Mg value of the solution becomes increasingly heavy. This suggests either preferential loss of light, and then heavy Mg from olivine, or that the secondary phase preferentially incorporates light Mg from solution. Assuming that the secondary phase is chrysotile, a Mg-silicate, the sense of Mg fractionation is opposite to that previously associated with silicate soils and implies that the fractionation of Mg isotopes during silicate precipitation may be mineral specific. If secondary silicates do preferentially remove light Mg from solution then this could be a possible mechanism for the relatively heavy δ26Mg value of seawater. This study highlights the utility of experimental studies to quantify the effects of natural weathering reactions on the Li and Mg geochemical cycles. 相似文献
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Statistical and hydrochemical methods to compare basalt- and basement rock-hosted groundwaters: Atherton Tablelands,north-eastern Australia 总被引：1，自引：0，他引：1
Multivariate analysis of physico-chemical and chemical data has enabled differentiation among groundwaters sourced from different lithological formations in the Atherton Tablelands region of north-eastern Australia. The main water resource is stored in basalt, although basement rocks such as granite and metamorphics also contain variable amounts of water. Groundwater in the basalt is mostly Mg-Ca-Na, HCO3 type, with electrical conductivities less than 300 µS/cm and pH values from 6.5 to 8.5. Some of the other groundwater is quite similar, making the identification of hydrochemical facies difficult. Groundwater samples were grouped based on the results of a principal component factor analysis of the major dissolved constituents H4SiO4, Na+, Ca2+, Mg2+ and HCO3-, as well as pH and electrical conductivity. Based on this differentiation it was possible to identify the likely host rocks of groundwaters from unidentified lithological units, define the basalt thickness and provide a better understanding of the groundwater resource. Principal component factor analysis has also been useful in identifying the likely hydrochemical processes controlling the composition of these groundwaters, including the production of weak acids in the soil layers, silicate mineral weathering, ion-exchange reactions, evapotranspiration and the leaching of ions from organic matter. Supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00254-002-0667-z. 相似文献
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凹凸石粘土与玄武岩的成因关系 总被引：4，自引：0，他引：4
在矿物组成研究的基础上，对比研究了凹凸棒石，蒙脱石，凹凸棒石粘土，蒙脱石粘土，玄武岩，风化玄武岩的化学组成。根据化学成分对比，分析了玄武岩与凹凸棒石粘土的成因关系，解释了玄武岩对凹凸棒石粘土的时空控制，结合地质观测，提出形成苏皖地区凹凸棒石粘土的物质成分基本上来源于玄岩的化学风化，但物质成分发生了较大的分异，凹凸棒石粘土不能直接同玄武岩经地表雨水的风化淋滤形成，而是玄武岩风化形成的蒙脱石经搬运沉积，再与镁质溶液反应形成，或凹凸棒石直接从富镁碱性溶液中结晶形成，凹凸棒石粘土形成的物理化学条件为偏碱性的还原条件。 相似文献
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彭州地区是＂5.12＂地震灾区,其震后的水文地球化学特征还未有相关研究,本文利用以热力学为基础的水文地球化学平衡理论与方法对彭州通济地区震后浅层地下水化学特征及其形成进行了分析,为研究地震对浅层地下水的影响提供基础信息。分析表明：研究区水化学场受到地形地貌的控制,水化学类型以HCO3--Ca型为主;HCO3-、Ca2＋普遍含量较高,CO2分压控制碳酸盐的溶解度及水中的pH值;其浅层地下水相对于石英处于过饱和状态,相对于非晶质SiO2处于未饱和状态,CO2气体参与硅酸盐矿物水解,产生可溶SiO2;矿物溶解及与水中化学组分平衡的非硅铝酸盐矿物主要为方解石,硅铝酸盐矿物主要为长石,其次是高岭石、蒙脱石。水化学平衡理论与方法可以较好的用于研究地下水所处的水文地球化学环境以及判断SiO2的来源和矿物溶解过程。 相似文献
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Groundwater sampling was accomplished in the basaltic sequence of the Rh?n mountain range, Germany, in order to investigate
hydrochemical groundwater evolution and to delineate mineral alteration reactions involved in natural weathering. The hydrochemical
compositions of near-surface groundwaters indicate a Ca/Mg–HCO3 type with near-neutral pH and evolve to a Na–HCO3 type with high pH at greater depth. Column experiments were performed with basaltic and phonolitic rock samples to determine
individual mineral alteration reactions. The basic reactions could be related to the alteration of olivine, Ca-pyroxene, plagioclase,
pyrrhotite, and feldspathoids under formation of secondary clay minerals (smectites, illite) and goethite. The mineral alteration
reactions deduced from the leaching experiments by inverse modelling were found to be consistent with the mineral reactions
associated with the natural groundwaters. The reactions calculated for groundwater evolution involve the alteration of primary
and secondary minerals to produce low-T mineral phase. The conversion of secondary Na-beidellite to illite occurs at a later
stage of groundwater evolution, reducing the concentrations of K+ and Mg2+. Near-surface groundwaters do not indicate significant cation exchange. Initial cation exchange requires elevated pH values,
with Mg2+ removed from solution preferred to Ca2+. Na-alkalisation of the groundwaters at greater depth suggests the exchange of Na+ for Mg2+ and Ca2+ on Na-beidellite, supported by cation exchange on coatings of iron hydroxides as alteration products. Among the mature high-pH
groundwater at greater depth, the dissolution of anorthite and albite has significant effect on groundwater composition. 相似文献