地下水矿物饱和度的水文地球化学模拟分析--以娘子关泉域岩溶水为例

通过分析娘子关泉域岩溶水的水文地质条件、岩溶发育规律以及水文地球化学特征，发现在该泉域内不应出现方解石、白云石、石膏等矿物溶解饱和状态。运用地球化学模拟软件PHREEQC模拟该区可能的化学条件（地下水中二氧化碳分压）及相应条件下的矿物溶解状态，同时结合野外溶解实验推断所处条件范围。这一研究推测出地下水与其溶解矿物所处极限状态应为饱和状态，而实际常常应处于非饱和状态，若计算为过饱和状态，则应可能是分析数据错误所致。     

深孔水力采矿碎岩与矿浆举升机具设计与试验

钻孔水力采矿技术作为一种新型非传统采矿方法,在开采易分散、疏松、多孔、弱胶结性等固体矿产时显示出独特的优点。基于钻孔水力采矿原理,主要对碎岩高压水枪工作原理和结构进行了研究,对矿浆举升系统等方面进行了优化设计,通过数值模拟分析和地表、孔内实物模型试验进行了设计验证,并研究了相应的钻孔水力采矿工艺,这些研究为未来深部固体矿产领域开发提供技术支撑。      

Modified Darcy''s law, Terzaghi''s effective stress principle and Fick''s law for swelling clay soils

Governing equations often used in soil mechanics and hydrology include the classical Darcy's law, Terzaghi's effective stress principle, and the classical Fick's first law. It is known that the classical forms of these relations apply only to non-swelling, granular materials. In this paper, we summarize recent generalizations of these results for swelling porous media obtained using hybrid mixture theory (HMT) by the authors. HMT is a methodical procedure for obtaining macroscopic constitutive restrictions which are thermodynamically admissible by exploiting the entropy inequality for spatially-averaged properties. HMT applied to the modeling of swelling clay particles, viewed as clusters of adsorbed water and clay minerals, produces additional terms necessary to account for the physico-chemical forces between the adsorbed water and clay minerals or, more generally, for swelling colloids. New directions for modeling consolidation of swelling clays are proposed based on our view of clay particles as a two-phase system.     

Alkali feldspar dissolution and secondary mineral precipitation in batch systems: 3. Saturation states of product minerals and reaction paths

In order to evaluate the complex interplay between dissolution and precipitation reaction kinetics, we examined the hypothesis of partial equilibria between secondary mineral products and aqueous solutions in feldspar-water systems. Speciation and solubility geochemical modeling was used to compute the saturation indices (SI) for product minerals in batch feldspar dissolution experiments at elevated temperatures and pressures and to trace the reaction paths on activity-activity diagrams. The modeling results demonstrated: (1) the experimental aqueous solutions were supersaturated with respect to product minerals for almost the entire duration of the experiments; (2) the aqueous solution chemistry did not evolve along the phase boundaries but crossed the phase boundaries at oblique angles; and (3) the earlier precipitated product minerals did not dissolve but continued to precipitate even after the solution chemistry had evolved into the stability fields of minerals lower in the paragenesis sequence. These three lines of evidence signify that product mineral precipitation is a slow kinetic process and partial equilibria between aqueous solution and product minerals were not held. In contrast, the experimental evidences are consistent with the hypothesis of strong coupling of mineral dissolution/precipitation kinetics [e.g., Zhu C., Blum A. E. and Veblen D. R. (2004a) Feldspar dissolution rates and clay precipitation in the Navajo aquifer at Black Mesa, Arizona, USA. In Water-Rock Interaction (eds. R. B. Wanty and R. R. I. Seal). A.A. Balkema, Saratoga Springs, New York. pp. 895-899]. In all batch experiments examined, the time of congruent feldspar dissolution was short and supersaturation with respect to the product minerals was reached within a short period of time. The experimental system progressed from a dissolution driven regime to a precipitation limited regime in a short order. The results of this study suggest a complex feedback between dissolution and precipitation reaction kinetics, which needs to be considered in the interpretation of field based dissolution rates.     

天津市塘沽低温热储回灌的水-岩相互作用地球化学模拟

地球化学模拟是了解早期阶段回灌影响的有效方法,对塘沽热田的地热回灌试验进行了地球化学模拟,以地热供暖尾水作为初始反应流体,通过模拟其与储层岩石的水－岩相互作用,确定回灌对储层性质的影响,模拟是根据回灌水在不同温度下分别与岩石反应及在不断升温过程中连续与岩石相互作用而进行的,结果表明,回灌的影响在开始阶段是相当重要的,在仅考虑溶解和沉淀矿物间体积平衡的情况下,回灌对储层的孔隙度产生正的效应,水－岩相     

Geochemistry of Rock-Forming Minerals in Mantle Xenoliths from Basalts of Sverre Volcano,Spitsbergen Archipelago

The paper reports the results of SIMS and SEM-EDS study of rock-forming minerals from melt pockets in the central part of a spinel peridotite xenolith taken from Quaternary alkaline basalts of Sverre Volcano in the northwestern part of West Spitsbergen Island. Olivine and clinopyroxene are analyzed to trace changes related to the metasomatic interaction between spinel lherzolite and a carbonate melt with formation of corresponding secondary minerals and silicate glass. It is established that the metasomatic interaction of the carbonate melt with minerals of host spinel lherzolite is accompanied by partial recrystallization of olivine and clinopyroxene, or crystallization of the second generation of these minerals. Percolating carbonate melt caused significant changes in the major, trace, and rare-earth element composition of the considered minerals, thus placing constraints on the use of the composition of these minerals for calculation of P–T parameters, estimating equilibrium, and modeling petrological processes in mantle.     

地质流体 岩石反应的地球化学动力学方法

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。     

影响油包裹体均一温度的主要控制因素及其地质涵义

成岩矿物中捕获的油包裹体已经广泛应用到油气成藏过程约束研究之中,但对油包裹体均一温度的影响因素及其地质涵义还了解得不够清楚.主要运用热动力学模拟的方法,通过模拟黑油和挥发性油两种不同原油类型在不同温-压条件下捕获时油包裹体均一温度与捕获时温度之间的关系,发现油包裹体的均一温度受到油组分、捕获温度和压力等多种因素影响;利...     

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka Marine Terrace Chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized [White A. F., Schulz M. S., Vivit D. V., Blum A., Stonestrom D. A. and Anderson S. P. (2008) Chemical weathering of a Marine Terrace Chronosequence, Santa Cruz, California. I: interpreting the long-term controls on chemical weathering based on spatial and temporal element and mineral distributions. Geochim. Cosmochim. Acta72 (1), 36-68] and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [Hellmann R. and Tisserand D. (2006) Dissolution kinetics as a function of the Gibbs free energy of reaction: An experimental study based on albite feldspar. Geochim. Cosmochim. Acta70 (2), 364-383] or the aluminum inhibition model proposed by Oelkers et al. [Oelkers E. H., Schott J. and Devidal J. L. (1994) The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochim. Cosmochim. Acta58 (9), 2011-2024], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site.Additionally, observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO₂(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws.     

基于Arc-WofE系统的证据权法在层控型铅锌成矿预测中的应用

通过分析四川宁南地区层控铅锌矿床成矿特征，建立了基于GIS平台的应用图层数据库，采用Arc-WofE系统进行证据权法模拟预测，划分出13个铅锌成矿远景区．通过对宁南地区现有矿床的分析，认为证据权法数学预测模型对区域成矿远景区于预测有较高的准确性和科学性，同时在和Arc—WofE系统结合后，可对多源信息进行空间位置综合处理并形成新的综合变量，能更全面、客观的反映地质体空间特征，使成矿预测更加准确．     

高斯射线束在金属矿产勘探中的模拟

根据高斯射线的方法原理编制程序,结合对中深层复杂构造的地震波场进行模拟研究,获得了高精度、高分辨率的正演记录。所作模型及计算结果显示:高斯射线束正演模拟方法技术不但能够清晰地反映出地层的剖面形态,而且也能反映出复杂的地质构造;同时,对波场(特别是金属矿产中的复杂波场)特征的认识可以提供有用的信息。      

Diffusion modeling as a tool for constraining timescales of evolution of metamorphic rocks

Summary The widespread discoveries of ultrahigh pressure rocks on the surface of the earth have considerably revised our view of rates of tectonic processes. Suitable tools are necessary to quantify the rapid rates involved in the production and preservation of ultrahigh pressure metamorphic features. It is shown here that diffusion modeling is a powerful and versatile tool for attaining this goal. The basic steps involved in the modeling process are outlined followed by a discussion of the considerable list of advantages. Major shortcomings are in the unavailability of high quality measurements of diffusion coefficients in key minerals, and in our theoretical understanding of diffusion processes in complex silicates. Two examples are provided of how recent technological and theoretical advances may contribute to overcoming these traditional hindrances, and thereby help to realize the full potential of diffusion modeling. Some sources of data on diffusion coefficients are provided in the last section.     

东昆仑造山带蛇绿岩矿物学特征及其岩石成因讨论

首次对东昆仑复合造山带不同时代蛇绿岩主要造岩矿物橄榄石、辉石、斜长石进行了系统的矿物化学研究 ,查明了不同蛇绿岩带在矿物成分上的差异 ,对清水泉蛇绿岩带和布青山蛇绿岩带单斜辉石、斜方辉石、斜长石进行了矿物稀土、微量元素的研究 ,阐明了矿物稀土、微量元素与全岩稀土、微量元素的关系 ,证明了在以辉石和橄榄石为主的橄辉岩中 ,单斜辉石的稀土元素基本上代表了全岩的稀土元素。根据地幔岩石中矿物成分特征 ,对不同蛇绿岩带地幔类型进行了讨论 ,并根据实测的辉石、斜长石分配系数 ,确定了清水泉蛇绿岩带玄武岩的部分熔融定量模拟     

Clay minerals in sediments of the hydrothermally active southern trough in the Guaymas Basin (Gulf of California)

The results of the study of clay mineral alterations in Upper Pleistocene sediments of the southern trough in the Guaymas Basin (Gulf of California) due to the influence of hydrothermal solutions and heat produced by sill intrusions are discussed. Core samples from DSDP Holes 477 and 477A were taken for the analysis of clay minerals. Application of the method of modeling X-ray diffraction patterns of oriented specimens of the finely dispersed particles made it possible to establish the phase composition of clay minerals, determine their structural parameters, and obtain reliable quantitative estimates of their contents in natural mixtures. The modeling data allowed us to characterize reliably the transformation of clay minerals in sediments of the hydrothermally active southern trough in the Guaymas Basin. In Upper Pleistocene sandy–clayey sediments of the southern trough, changes in the composition of clay minerals occurred under the influence of a long-living hydrothermal system. Its lower part (interval 170.0–257.5 m) with maximum temperatures (~300°C) was marked by the formation of chlorite. Terrigenous clay minerals are not preserved here. Saponite appears at a depth of 248 m in the chlorite formation zone. Higher in the sedimentary section, the interval 146–170 m is also barren of terrigenous clay minerals. Sediments of this interval yielded two newly formed clay minerals (chlorite and illite), which were formed at lower temperatures (above 180°C and below 300°C, approximately up to ~250°C), while the relatively low-temperature upper part (110–146 m) of the hydrothermal system (from ~140°C to ~180°C) includes the mixture of terrigenous and newly formed clay minerals. Terrigenous illite is preserved here. Illitization of the mixed-layer illite–smectite was subjected to illitization. The terrigenous montmorillonite disappeared, and chlorite–smectite with 5–10% of smectite layers were formed. In the upper interval (down to approximately 110 mbsf), the composition of terrigenous clay minerals remains unchanged. They are composed of the predominant mixed-layer illite–smectite and montmorillonite, the subordinate illite, mixed-layer chlorite–smectite with 5% of smectite layers, mixed-layer kaolinite–smectite with 30% of smectite layers, and kaolinite. This composition of clay minerals changed under the influence of sill intrusions into the sedimentary cover at 58–105 m in the section of Hole 477. The most significant changes are noted in the 8-m-thick member above the sill at 50–58 m. The upper part of this interval is barren of the terrigenous mixed-layer illite–smectite, which is replaced by the newly formed trioctahedral smectite (saponite). At the same time, the terrigenous dioctahedral smectite (montmorillonite) is preserved. The composition of terrigenous clay minerals remains unchanged at the top of the unit underlying the sill base.     

基于IDL的三维地质动态建模

三维地质建模凭借着形象直观、操作简单、功能丰富的优势,广泛应用于地质、矿产、工程等领域。在讨论表面建模与实体建模方法的基础上,开发程序探索了其在交互式数据语言（IDL）平台上的实现过程,并初步建立了可以应用于滑坡、泥石流、地面沉降等动态过程展示的算法。最后以煤田与泥石流模型的构建与可视化作为实例进行了效果验证。经测试,IDL可以较好地完成三维地质建模任务,并且在插值、剖分等方面表现了自己的优势,为工程地质信息化的实现提供了一种思路。      

矿物包裹体弹性拉曼频移温压计原理及其地质应用

与目前广泛存在的传统热力学温压计相比,矿物包裹体拉曼弹性温压计是一种独立于化学平衡之外的基于力学平衡的新型温压计。其原理是利用激光拉曼频移标定矿物包裹体在常压条件下储存的残余应力,结合包裹体与寄主两相矿物弹性物理特性,可准确恢复包裹体捕获时的温度和压力条件,是一个潜在的优质温压计。作为新发展起来的技术和方法,越来越多地引起地质学家的关注,但是目前大量的研究还集中于对该温压计自身的推演和校正,而对于天然样品的研究还相对缺乏。近来年,学者们成功地将拉曼弹性矿物温压计应用到各类天然样品的研究中。有限的研究表明拉曼弹性矿物温压计具有较大的应用范围,不仅是一个潜在的优质地质温压计,而且可广泛应用于恢复俯冲带受后期热事件强烈改造的高压-超高压变质信息,进而示踪地球早期俯冲带演化的动力学过程。因此矿物包裹体拉曼弹性温压计具有广泛的地质用途和应用前景。     

Behavior of arsenic and geochemical modeling of arsenic enrichment in aqueous environments

Arsenic is present in aqueous environments in +III and +V oxidation states. In oxidizing environments, the principle attenuation mechanism of As migration is its adsorption on Fe(III) oxide and hydroxides. The adsorption affinity is higher for As(V) under lower pH conditions and for As(III) under higher pH conditions. Ferric oxide and hydroxides can dissolve under low Eh and pH conditions releasing adsorbed As. Oxidation-reduction processes often involve high organic matter content in sediments and also contamination by organics such as BTEX. Arsenic may desorb under high pH conditions. Changes of pH can be related to some redox reactions, cation exchange reactions driving dissolution of carbonates, and dissolution of silicates. In very reducing environments, where SO₄ reduction takes place, secondary sulfide minerals like As-bearing pyrite and orpiment, As₂S₃, can incorporate As. Geochemical modeling can be divided into two principal categories: (a) forward modeling and (b) inverse modeling. Forward modeling is used to predict water chemistry after completion of predetermined reactions. Inverse modeling is used to suggest which processes take place along a flowpath. Complex coupled transport and geochemistry programs, which allow for simulation of As adsorption, are becoming available. A common modeling approach is based on forward modeling with surface complexation modeling (SCM) of As adsorption, which can incorporate the effect of different adsorbent/As ratios, adsorption sites density, area available for adsorption, pH changes and competition of As for adsorption sites with other dissolved species such as phosphate. The adsorption modeling can be performed in both batch and transport modes in codes such as PHREEQC. Inverse modeling is generally used to verify hypotheses on the origin of As. Basic prerequisites of inverse modeling are the knowledge of flow pattern (sampling points used in model have to be hydraulically connected) and information about mineralogy including As mineral phases. Case studies of geochemical modeling including modeling of As adsorption are presented.     

The use of location–allocation techniques for exploration targeting of high place-value industrial minerals: A market-based prospectivity study of the Spanish gypsum resources

Prospectivity mapping is used to define favorable areas for mineral exploration. The location–allocation modeling can help in ranking exploration zones for high-volume low-price industrial minerals. This type of minerals are said to have a high place-value, meaning that they derive much of their value from the fact that extraction points are located close to the demand points. With this aim, a GIS-based location–allocation model of the gypsum resources in Spain is presented in this paper. Results point to the recognition of the most interesting areas that should be investigated and places where new gypsum facilities could be located. Moreover, the model allows evaluation of the relative economic interest of the new areas as compared with the existing ones.Based on this modeling, the geological regions with the greatest potential to place new facilities are located in the northwestern (Cantabrian zone) and north-eastern (easternmost Catalonia) parts of the Iberian Peninsula, with potential market share values higher than 5.25%. Most of the economically interesting gypsum bearing units in these regions are of Mesozoic age, although Neogene deposits of the central part of Catalonia are not ruled out. In addition, the prospectivity analysis map leads to establish an area where the excess of gypsum factories results in a drastic decrease of the market share value within this region (< 1.84 %).The maps obtained with this prospectivity analysis help in the area selection and the target identification phases of a mineral exploration. The model could easily be used for other similar high place-value industrial minerals and rocks.     

Some remarks on fabric overprints and constrictional AMS fabrics in igneous rocks

During the ascent, emplacement and post-emplacement deformation of igneous rocks, two or more phases of deformation that overprint each other are often depicted. These overprints, when magnetic minerals are present, are recorded in magnetic fabric. In this contribution, overprints are studied by means of numerical modeling, following several basic scenarios common to igneous rocks. Biotite and amphibole that occur often together in igneous rocks are considered as carriers of the anisotropy of magnetic susceptibility. Modeling shows that (1) a constrictional fabric with a low degree of anisotropy as commonly recorded in magmatic rocks may result from a deformation overprint and not necessarily from an extensional/transtensional regime, and (2) that the constrictional AMS fabrics originates from orthogonal superimposition of a deformation event on an AMS fabric inherited from earlier magma emplacement history. Therefore, the interpretation of a constrictional fabric must be performed with caution. Numerical modeling may provide a suitable help in strengthening the interpretation of real magnetic fabric data.     

云南个旧高松矿田芦塘坝研究区三维预测模型及靶区优选

通过对云南个旧芦塘坝研究区成矿信息分析,结合三维可视化技术,对其进行深部隐伏矿体预测。根据研究区的地质概况与成矿规律,确定地层和断裂是主要的控矿条件,利用三维建模软件建立该研究区的数字矿床模型,应用立方体预测模型找矿方法,提取成矿有利因子——地层、断裂、构造定量化信息、化学元素异常,将其作为预测变量,最终通过计算圈定出预测远景区进而优选出4个预测靶区。预测远景区结果表明,该研究区有较好的找矿潜力,其矿产预测方法有效性较好。构造定量化信息分析方法的应用有助于实现三维找矿。