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1.
Accurate precipitation is the basis for better understanding the climate change and water cycle process. The domestic and foreign scholars have done a great deal of work for the insufficient catch rate of rain gauges. A review of recent studies on correction of errors in precipitation measurement was given in this paper. It is considered that the correction scheme for liquid precipitation is mature at present, but there is not a uniform standard for solid precipitation correction. The main reason is that the current precipitation correction schemes are lack of consideration of precipitation micro process. The full consideration of the precipitation micro process is the key to the correction of precipitation with physical significance. In addition, more detailed precipitation type determination and the record of light precipitation events are also key problems to determine the precipitation correction scheme. 相似文献
2.
自然重砂测量是矿产勘查的重要手段之一。如何充分提取自然重砂测量数据所蕴涵的矿化信息,发挥其在矿产资源调查中的作用是一个现实问题。重矿物的被剥蚀、再沉积是自然重砂异常形成的重要过程。在充分考虑自然降水的汇集路径的前提下,以汇水区域边界确定范围是对自然重砂异常客观的解释。区域成矿模式研究、地球化学和人工重砂资料对自然重砂测量数据应用是重要的补充。笔者通过蔚县地区1∶20万自然重砂测量数据的分析,对其中有关全面认识异常、合理确定异常、勘查方法的综合应用、软件平台的使用及在矿产开发程度较高地区寻找未知资源的途径等方面做了一些探讨和尝试。 相似文献
3.
Patricia Acero Luis F. Auqué María J. Gimeno Javier B. Gómez 《Environmental Earth Sciences》2010,59(8):1613-1628
In this study, the potential for mineral precipitation reactions to occur during the excavation, disposal, backfilling and
closure of a deep geological repository for the final disposal of spent nuclear fuel was evaluated with the assistance of
hydrogeochemical modelling. Four modelling exercises, corresponding to the main expectable geochemical scenarios in the Excavation
Damaged Zone (EDZ) throughout repository evolution, were carried out and the times for sealing of the discontinuities owing
to mineral precipitation in each of them were evaluated and discussed. The simulations show that mineral precipitation reactions
are thermodynamically feasible in most of the studied cases. The main mineral phases potentially responsible for the hydraulic
sealing of the EDZ are calcite and ferric oxyhydroxides, being the estimated volumes occupied by the precipitation of calcite
between one and three orders of magnitude larger than the volume of precipitating ferric phases. The estimated times for complete
sealing of the EDZ may vary between several hundreds to more than 1 million years. The shortest sealing times (less than 3,000 years)
are obtained for the mixture of groundwaters from the repository depth with dilute infiltration waters. 相似文献
4.
在野外和室内岩相学观察的基础上,详细剖析了蚀变-矿化时序,结合热力学数值模拟方法与定量结果,厘定了水-
岩反应过程中矿物的沉淀次序、流体组分的存在形式、迁移行为、浓度变化和矿物形成机制以及组分之间的化学反应,为
进一步研究水-岩反应与金矿化的关系奠定了基础。研究结果显示反应初期K+由流体带入围岩形成钾长石化,随着反应的
进行,H+浓度持续降低而Fe2+和Al3+含量升高,绢云母和石英大量沉淀,钾长石消失;反应后期各类硫化物开始沉淀,石英
持续沉淀贯穿整个反应过程。成矿流体中SO42-,HS-,Fe2+的含量对蚀变矿物组合影响很大;水-岩反应过程中硫酸盐
（SO42-） 减少生成等量的HS-并伴随着含三价铁矿物的沉淀,可能是焦家金矿床硫化物沉淀的一种重要机制。整个反应过程
中溶液pH值持续升高是原岩中Ca,K,Na,Mg等与溶液中H+发生交换反应的结果;同时pH值的升高也会降低金的溶解度
致使金沉淀。上述研究成果对于理解岩石中的矿物共生组合、生成顺序及蚀变分带的成因机制提供了新的依据。 相似文献
5.
辽吉成矿带上广泛分布着热液型铅锌矿床,对于该类型矿床中矿物共生组合特征和成矿物质迁移沉淀机制的研究是矿床学研究的核心问题之一。通过共生矿物热力学平衡的相关计算,绘制热力学lg[Cu2+]-pH、lg[HS−]-pH和Eh-pH相图,可以有效地诠释成矿流体中成矿元素在迁移、沉淀过程中的物理化学条件。本文以辽吉成矿带上典型的热液型铅锌矿床——岫岩红旗铅锌矿床为例,在对该矿床进行镜下典型矿物共生组合研究的基础上,选取了黄铁矿、黄铜矿、方铅矿和闪锌矿四种矿物进行热力学平衡的相关计算,选取473 K、549 K、648 K三个温度截面绘制了热力学lg[Cu2+]-pH、lg[HS−]-pH和Eh-pH相图,结果显示成矿流体中矿物迁移沉淀机制和矿物共生组合的形成主要受成矿流体的温度、离子活度、pH、Eh多因素制约。此研究对于解释辽吉成矿带上典型热液型铅锌矿床的运移沉淀机制和矿物组合特征具有重要的指导意义。 相似文献
6.
地球深部物质和能量交换的动力过程与矿产资源的形成 总被引：46，自引：4，他引：46
滕吉文 《大地构造与成矿学》2003,27(1):3-21
地球深部物质与能量的交换和深层动力过程这一科学问题的提出,乃是近年来地球科学发展与逐步向量化“进军”的必然,它是探索一系列地学前沿课题的基础。地球表面所见到的一系列地球物理场异常,地质构造格局,地球化学组分变异,无一不受到地球内部物质与能量的交换和深层动力过程的制约。如地球圈层的形成与演化,大陆伸展与裂谷,资源与能源等,均为深部物质运移和物理学、化学效应及地质构造耦合的产物。本文讨论了金属矿产资源与地壳、地幔结构及深部物质运移的动力学响应。通过几个典型矿床和其形成要素分析了成矿作用的深层动力过程。文中主要讨论了五个方面的问题:第一,金属矿产资源成矿和分布与地壳、地幔结构及深部物质运移和成矿带。第二,金的形成与深层过程。第三,金属矿床的形成、演化和分布与深部物质及能量的交换。第四,地幔热柱与成矿作用。第五,地球内部深层动力过程与流体运移和必须深化研究的几个问题。 相似文献
7.
韧性剪切带内流体作用的研究 总被引：10，自引：3，他引：7
韧性剪切带内的流体作用是一种复杂的构造物理化学过程和力学－化学的耦合过程。它不仅影响着岩石的变形机制,促进变形构造的发生和发展,而且影响着岩石的矿物组成及化学成分的变化。本文在综合评价现有研究成果的基础上认为,岩石的成分变异和体积变化是韧性前切带内流体作用研究的主要内容,韧性剪切带内构造－流体演化历史,构造物理化学、岩石应变模式及其特征的研究是今后韧性剪切带内流体作用研究的发展方向和前沿领域。 相似文献
8.
铀矿床定年研究进展评述 总被引：8，自引：3，他引：5
往往由于铀矿物(沥青铀矿)颗粒细小、易蚀变成铀的次生矿物及多期铀矿化作用相互叠加等在组成和结构上的固有特点,通常难以用挑选铀矿物(沥青铀矿)样品溶样的传统定年方法精确确定其形成年龄。随着分析技术的不断更新和发展,对铀矿床成矿年代学的研究也不断深入。但受铀矿床中铀矿物U-Pb定年方法本身的制约,以及以往对铀矿物U-Pb定年体系中铀矿物样品要求认识的不足,常常导致获得的年龄无实际地质意义或无法获得理想的等时线年龄。本文针对铀矿化定年方法的发展历程进行了系统梳理和分析,评述了铀矿物定年的五种主要方法:(1)铀矿物U-Th-totalPb化学年龄;(2)铀矿物模式年龄;(3)铀矿物传统等时线年龄;(4)铀矿物矿伴生矿物年龄;(5)原位微区铀矿物U-Pb年龄。在此基础上,深入探讨了铀矿化作用定年研究中存在的问题和对应方案,期望促进未来铀矿床成矿年代学的发展。 相似文献
9.
纳米比亚湖山铀矿位于达马拉造山带的中央南部地区,工业铀矿物为晶质铀矿,属于伟晶岩型铀矿床。关于不同矿石中铀元素的富集与沉淀机制还存在一定争议。为了揭示伟晶质岩浆演化与铀矿化作用的关系,本文对矿区内不同矿物组成的伟晶岩型矿石开展了岩石和矿物地球化学研究。野外及镜下鉴定结果显示,矿化伟晶岩可以分为“简单类型”矿体和“复杂类型”矿体。前者具有正常的花岗伟晶结构,晶质铀矿均匀分布于造岩矿物之间,矿化程度低到中等;后者表现出非均匀的结构特征,且矿化程度极高,晶质铀矿在成因上与大量黑云母团块有明显的空间联系。地球化学研究表明:在“简单类型”伟晶岩中,铀元素主要通过伟晶质岩浆的分离结晶作用富集;“复杂类型”伟晶质岩浆的演化则明显受控于同化混染作用,其铀矿化为岩浆同化混染与分离结晶(assimilation-fractional crystallization,AFC)作用产物。具体而言,外来基性组分(FeO,MgO,TiO2,MnO)的混入导致“复杂类型”熔体中矿物的结晶顺序发生改变,长石类矿物的“延后”结晶为黑云母提供了更加有利的结晶空间和条件,促使黑云母以团块状聚集的形式产出。黑云母的大量析出会引发残余岩浆中UFm4-m络合物的水解,导致晶质铀矿在团块黑云母内部或周围沉淀。因此,本文有关“简单类型”和“复杂类型”产铀伟晶岩的研究,有效地揭示了岩浆演化过程与铀矿化机制,丰富了伟晶岩型铀矿床理论,为后期勘查开发提供了科学依据。 相似文献
10.
Mineral Composition of Loess—Paleosol Samples from the Loess Plateau of China and Its Environmental Significance 总被引：1，自引：0，他引：1
34samples of loess-paleosol from the Luochuan and Xifeng sections in the Loess Plateau,northern China were eparated into sand,silt and clay fractions and analyzed for their mineral compositions.The results indicate that there is almost no difference between loess and paleosol in mineral composition.Major mineral species are quartz,mica,feldspar and chlorite,accounting for about 88-92% of the total;other minerals are kandite,smectite,vermiculite and a few heavy minerals.The calcite,magnetite and hematite were not taken into consideration because of their removal in the process of sample preparation.The main difference with respect to the mineral composition of samples collected from different sections and different statigraphic levels lies in the amount and grain size of minerals hosted.Comparisons between the Luochuan section and the Xifeng section,between paleosol and loess and between the upper part and the lower part of some paleosol layers show that the formers contain less feldspar but more mica and vermiculite and are finer in grain size,indicating the co-occurrence of both biochemical weathering process responsible for mineral change and physical weathering process leading to grain-size change during the soil-forming processes.This result favours such an explanation of the soil-forming mechanism that loess deposition and paleosol development occurred synchronously,though the rate of soil formation was greater than that of loess deposition,thus leading to soil development. 相似文献
11.
Yuyu Wan Shanghai Du Guangyu Lin Fengjun Zhang Tianfu Xu 《Environmental Earth Sciences》2017,76(1):43
This study focused on typical injection layers of deep saline aquifers in the Shiqianfeng Formation used in the Carbon Capture and Sequestration Demonstration Projects in the Ordos Basin, Northwest China. The study employed experiments and numerical simulations to investigate the mechanism of CO2 mineral sequestration in these deep saline aquifers. The experimental results showed that the dissolved minerals are plagioclase, hematite, illite–smectite mixed layer clay and illite, whereas the precipitated minerals are quartz (at 55, and 70 °C) and kaolinite (at 70 °C). There are rare carbonate mineral precipitations at the experimental time scale, while the precipitation of quartz as a product of the dissolution of silicate minerals and some intermediate minerals rich in K and Mg that transform to clay minerals, reveals the possibility of carbonate precipitation at the longer time scale. These results are consistent with some results previously reported in the literature. We calibrated the kinetic parameters of mineral dissolution and precipitation by these experimental results and then simulated the CO2 mineral sequestration under deep saline aquifer conditions. The simulation results showed that the dissolved minerals are albite, anorthite and minor hematite, whereas the precipitated minerals are calcite, kaolinite and smectite at 55 and 70 °C. The geochemical reaction of illite is more complex. At 55 °C, illite is dissolved at the relatively lag time and transformed to dawsonite; at 70 °C, illite is precipitated in the early reaction period and then transformed to kaolinite. Based on this research, sequestrated CO2 minerals, which are mainly related to the temperature of deep saline aquifers in Shiqianfeng Fm., are calcite and dawsonite at lower temperature, and calcite at higher temperature. The simulation results also establish that calcite could precipitate over a time scale of thousands of years, and the higher the temperature the sooner such a process would occur due to increased reaction rates. These characteristics are conducive, not only to the earlier occurrence of mineral sequestration, but also increase the sequestration capacity of the same mineral components. For a sequestration period of 10,000 years, we determined that the mineral sequestration capacity is 0.786 kg/m3 at 55 °C, and 2.180 kg/m3 at 70 °C. Furthermore, the occurrence of mineral sequestration indirectly increases the solubility of CO2 in the early reaction period, but this decreases with the increase in temperature. 相似文献
12.
碳酸盐型盐湖卤水的模拟太阳池结晶试验 总被引：1，自引：0，他引：1
在碳酸盐型盐湖提锂工艺中, 太阳池是一个重要组成部分, 目的是储存太阳能能量以结晶析出碳酸锂。文章利用加热方法首次在实验室条件下进行模拟太阳池结晶试验, 试验的蒸发量随着温度的升高而加大, 但蒸发量的不同对析盐结晶影响不大。在不同时间段模拟试验中, 24 h时间段的Mg2+析盐浓度较Li+大, 且随着时间的延长逐渐降低, 而Li+则相反;Mg2+析出速率随着时间的增加而逐渐降低, 而Li+析出速率基 本保持一致。在不同温度模拟试验中, 卤水主要组分总析出率与温度的升高呈正相关, 卤水中CO32?和Li+的浓度降低速度大于其他组分, CO32?和Li+的析出率远大于其他组分, 析出主要矿物鉴定结果均为扎布耶石 相似文献
13.
在活动造山带的研究中,剥蚀作用被认为与大气降水有着密切的关系,并且越来越
多的研究证据发现,气候因子在山脉的演化中承载了重要的影响力,降水被认为是活动造山
带剥蚀作用的动因。研究者用降水量和剥蚀强度的对应来阐释气候对山脉演化的制约。然而
也有学者提出反面例证来否定降水量与山脉剥蚀强度之间的耦合关系,进而否定气候因子在
活动造山带构造演化中的影响。由此而提出的科学问题是：降水究竟与剥蚀强度有没有关
联？降水怎样影响剥蚀强度,遵循怎样的机理？在详细分析活动造山带剥蚀作用过程和机理
的基础上,本文提出了降水势能的概念,在校验和整合TRMM 降水量数据与Etopo1 数字地貌
数据体之后,计算了喜马拉雅造山带的降水势能空间分布。同时,收集整理了喜马拉雅造山
带内已公开发表的磷灰石裂变径迹（AFT）年龄数据,以此为数据库获取了喜马拉雅剥蚀强度
时空分布格局。通过这两个数据体的定量分析,研究发现,喜马拉雅造山带内,剥蚀强度与
降水势能之间有很好的空间耦合性。这说明, 在喜马拉雅构造带, 现今的AFT 年龄空间分
布,是受气候作用主导的。进一步的研究发现,喜马拉雅带大约2.8 Ma 以来的AFT 年龄与现
今的降水势能秩相关性显著,且有局部最优的线性相关性,说明喜马拉雅带的剥蚀空间分布
受第四纪以来很年轻的地质历史时期的地表降水过程所控制。最新的气候样式决定了现今的
降水过程,控制了造山带剥蚀强度的空间分布。 相似文献
14.
Mineral-microbe interactions: a review 总被引：2，自引：0，他引：2
Hailiang DONG 《Frontiers of Earth Science》2010,4(2):127-147
The studies of mineral-microbe interactions lie at the heart of the emerging field of Geomicrobiology, as minerals and rocks
are the most fundamental earth materials with which microbes interact at all scales. Microbes have been found in a number
of the Earth’s extreme environments and beyond. In spite of the diverse geological environments in which microbes are found
and diverse approaches taken to study them, a common thread, mineral-microbe interactions, connects all these environments
and experimental approaches under the same umbrella, i.e., Geomicrobiology. Minerals and rocks provide microbes with nutrients
and living habitats, and microbes impact rock and mineral weathering and diagenesis rates through their effects on mineral
solubility and speciation. Given a rapid growth of research in this area in the last two decades, it is not possible to provide
a comprehensive review on the topic. This review paper focuses on three area, i.e., microbial dissolution of minerals, microbial
formation of minerals, and certain techniques to study mineral-microbe interactions. Under the first area, three subjects
are reviewed; they include siderophores as important agents in promoting mineral dissolution, microbial oxidation of reduced
minerals (acid mine drainage and microbial leaching of ores), and microbial reduction of oxidized minerals. Under the second
topic, both biologically controlled and induced mineralizations are reviewed with a special focus on microbially induced mineralization
(microbial surface mediated mineral precipitation and microbial precipitation of carbonates). Under the topic of characterization,
the focus is on transmission electron microscopy (TEM) and electron energy loss spectroscopy. It is the author’s hope that
this review will promote more focused research on mineral-microbe interactions and encourage more collaboration between microbiologists
and mineralogists. 相似文献
15.
Josip Terzić Tamara Marković Jasmina Lukač Reberski 《Environmental Earth Sciences》2014,72(4):1129-1142
Miljacka is a karst spring situated in Dalmatia, Croatia. The interpretation of the Miljacka Spring catchment area boundary has repeatedly changed in the past, and the main conclusions of previous studies were that the spring, which is located in the Krka River canyon, receives all of its water from another karst river, Zrmanja. Here, we review a new hypothesis that the Miljacka Spring receives some of its water from the Krka River. It was not possible to verify the hypothesis by solely studying the geological composition, structural–tectonic relations and tracer test results. Therefore, a hydrochemical study was performed to confirm the hypothesis. By studying the geological composition, it was found that part of the catchment area of the Krka River is built of evaporites (gypsum and anhydrite), which are different in their mineral composition than carbonates, the usual rock mass of the Dinaric karst. The hydrochemical model was made using the NETPATH-WIN and PHREEQC software packages. The mixing model results confirmed the hypothesis that the Miljacka Spring waters come from both the Zrmanja (including smaller proportion of precipitation infiltrated directly in the karst aquifer) and Krka rivers. This case study shows the great importance of the application of hydrochemical investigations in karst hydrogeology, where research is often difficult due to the complexity of the groundwater system. 相似文献
16.
大气降水是抚松县矿泉水资源的重要补给来源,探究其变化规律及极值概率对泉流量是否能够得到持续补给具有重要意义。为此,首先利用1960~2013年的降水资料和1981~2008年部分泉流量观测数据,对抚松县降水量的年内分配、年际变化和不同年代降水量均值变化进行降水特征分析;之后,运用皮尔逊Ⅲ型模型分析最大年降水量的概率分布;接着,利用1981年7月~2008年11月期间降水量和部分泉的泉流量监测数据,采用连续小波分析法对二者周期进行分析;最后,运用交叉小波变换法对同一时段内降水量和泉流量多时间尺度变化的相关性进行分析。结果表明:1960~2013年的54间,研究区内年降水量呈现周期性变化,变差系数为1.017×10-17,降水稳定,未发生异常变化。降水量和泉流量均存在约11个月的主震荡周期,二者属于同相位(即泉流量对降水量的变化产生即刻反应),降水量作为本区矿泉水补给的重要影响因素,可为矿泉水资源得到有效补给提供保证。 相似文献
17.
Industrial uranium orebodies have recently been found through in-depth uranium exploration in the Luohe Formation in the southwestern Ordos Basin, which is an important breakthrough in deep prospecting for sandstone-type uranium deposits. The composition, content and characteristics of clay minerals in the Luohe Formation in the Zhenyuan area were systematically studied by means of thin section identification, scanning electron microscopy, X-ray diffraction and altered mineral spectral scanning. Unlike the most important uranium-bearing rock series in the Zhiluo Formation in the northeast and southwest of the basin, the ore-bearing Luohe Formation sandstone has low contents of clay minerals while the clay mineral assemblages vary in different sand bodies. Among them, the main types of mudstone, oxidized sandstone, calcareous sandstone and mineralized sandstone are illite-smectite mixed-layer mineral and illite, followed by kaolinite and chlorite, the main types uranium-rich sandstone and gray-green sandstone are kaolinite and illite-smectite mixed-layer mineral, followed by illite and chlorite. Even though adsorption of clay minerals, such as chlorite, illite-smectite mixed-layer mineral, kaolinite, and illite may contribute to U enrichment and uranium mineral precipitation, no correlation between clays and uranium minerals have been observed, indicating that clay minerals are not the main factor affecting uranium enrichment during the deep metallogenic process. The study of clay minerals in the Luohe Formation sandstone demonstrated that there are at least two phases of chlorite and one phase of kaolinite in the study area, which respectively represent two phases of alkaline fluid and one phase of acid fluid activities, revealing a fluid phase transition of alkaline-acidic-alkaline. Therefore, the clay minerals can be used as an important indicator for uranium mineralization. © 2020, Science Press. All right reserved. 相似文献
18.
Carbon dioxide enhanced oil recovery (CO2-EOR) has been widely applied to the process of carbon capture, utilization, and storage (CCUS). Here, we investigate CO2–oil–water–rock interactions under reservoir conditions (100 °C and 24 MPa) in order to understand the fluid–rock interactions following termination of a CO2-EOR project. Our experimental results show that CO2-rich fluid remained the active fluid controlling the dissolution–precipitation processes in an oil-undersaturated sandstone reservoir; e.g., the dissolution of feldspar and calcite, and the precipitation of kaolinite as well as solid phases comprising O, Si, Al, Na, C, and Ti. Mineral dissolution rates were reduced in the case that mineral surfaces were coated by oil. Mineral wettability and composition, and oil saturation were the main controls on the exposed surface area of grains, and mineral wettability in particular led to selective dissolution. In addition, the permeability of the reservoir decreased substantially due to the precipitation of kaolinite and solid-phase particles, and due to the clogging of less soluble mineral particles released by the dissolution of K-feldspar and carbonate cement, whereas porosity increased. The results provide insight into potential formation damage resulting from CO2-EOR projects. 相似文献
19.
Alexandro Scislewski 《Geochimica et cosmochimica acta》2010,74(24):6996-7007
Mineral dissolution and precipitation reactions actively participate to control fluid chemistry during water-rock interaction. However, it is difficult to estimate and normalize bulk reaction rates if the mineral surface area effectively participating in the reactions is unknown. In this study, we evaluated the changing of the reactive mineral surface area during the interaction between CO2-rich fluids and albitite rock reacting under flow-through conditions. Our methodology, adopting an inverse modelling approach, is based on the measured chemical fluid composition as raw data. We estimated the rates of dissolution and the reactive surface areas of the different minerals by reconstructing the chemical evolution of the interacting fluids. This was done by a reaction process schema that was defined by a fractional degree of advance of the irreversible mass-transfer process and by attaining the continuum limit during the water-rock interaction. Calculations were carried out for albite, microcline, biotite and calcite assuming that the ion activity of dissolved silica and aluminium ions was limited by the equilibrium with quartz and kaolinite.We found that the absolute dissolution rate of albite, microcline, biotite and calcite remains essentially constant as a function of time, and the calcite dissolution rate is orders of magnitude higher than silicate minerals. On the contrary, the reactive surface area of the parent minerals varied by more than two orders of magnitude during the observed reaction time, especially for albite. We propose that the reactive surface area depends mainly on the stability of the secondary mineral coating that may passivate the effective reactive surface area of the parent minerals. 相似文献
20.
A coupled hydro-chemo-mechanical numerical model is developed for these coupled phenomena in many engineering fields. The
model has been applied to predicting the response of a stressed rockmass column to an injected reactive fluid (reagent) flow.
The response includes evolutions of porosity, permeability, reagent and mineral concentrations during dissolution. In the
model, the progress of dissolution is defined by the change in porosity ratio and the porosity increases with dissolution
assuming there is no precipitation. The numerical evolutions of porosity, permeability, reagent and mineral concentrations
during dissolution are validated against steady state solutions. The model results show that these evolutions are regulated
to a certain extent by the applied external loadings: an applied extensional stress enhances the progress of the dissolution
process while an applied compression stress slows the progress of the dissolution process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献