共查询到19条相似文献，搜索用时 46 毫秒
1.
长石类矿物是地壳中最常见的硅酸盐矿物,其风化作用对地球表面环境有显著影响,因而是风化作用研究的重点矿物之一。文中以长石为例,对硅酸盐矿物的风化作用研究现状从矿物的自然风化、模拟矿物化学风化和矿物的生物风化3个方面进行阐述;对影响矿物风化的各种因素及其在风化过程中所起的作用,以及长石微生物风化作用的机理和过程进行分析;指出目前硅酸盐矿物风化研究中存在的问题,并对未来的发展方向提出建议,指出对微生物-矿物复合体微环境物理化学性质的深入研究可能成为揭示微生物-矿物相互作用机理的一个突破口。 相似文献
2.
3.
含镁硅酸盐矿物是重要自然资源,国内外大都采用传统的化学方法进行开发利用,而微生物法释放含镁硅酸盐矿物中镁和硅的研究还未见报道。试验采用摇瓶培养与对照结合的方法研究烟曲霉(Aspergillusfumigatus)对含镁硅酸盐矿物——蛇纹石和橄榄石的风化作用。试验采用ICP-OES测定第5、10、20、30 d培养液滤液中Mg2+和Si的含量,同时对相应试样的pH值和代谢产物进行分析测定,采用SEM和TEM观察作用后的微生物-矿物聚集体。结果表明,烟曲霉作用蛇纹石和橄榄石试样滤液中的Mg2+和Si含量变化不仅与烟曲霉生长状况有关,而且与矿物的晶体结构相关,蛇纹石较橄榄石更易被烟曲霉风化;另外烟曲霉在生长过程中产生的酸性代谢产物有助于对矿物的风化;SEM和TEM观察结果直观地显示出烟曲霉对蛇纹石和橄榄石的风化作用痕迹。综合分析认为,烟曲霉对蛇纹石和橄榄石的风化作用应该是酸溶作用、菌丝对矿物的穿插包裹和菌丝体对养分的吸收等方式协同作用的综合效果。研究结果为探讨真菌与矿物相互作用的过程与机理以及为微生物法开发蛇纹石和橄榄石矿产资源提供了基础资料。 相似文献
4.
云南尖山磷块岩矿床是原生富集和风化富集两个阶段共同作用的产物。生物化学聚磷、物理富集成矿的原生富集形成了本区原生碳酸盐类磷块岩;适宜的风化作用,使原生磷块岩中的碳酸盐矿物大量溶解流失,从而形成风化富集磷块岩。原生磷块岩最终为机械作用下的产物,风化磷块岩最终为风化作用下的产物,它是以原生富集的碳酸盐类磷块岩为成矿物质基础的。二次富集作用大大提高了本区磷块岩的质量,从而也提高了其工业利用价值。 相似文献
5.
岩石矿物的微生物风化是地球表层系统最为活跃和普遍发生的地质营力之一。微生物对含钾岩石(以硅酸盐矿物为主)的风化能够释放其中的钾、硅和钙等元素,并在合适的环境条件下促进矿物元素的碳酸化沉淀,这是地表元素地球化学循环的重要环节之一。微生物对岩石的生物转化作用既涉及微生物的生长繁殖和代谢调控,也与元素的迁移转化和次生矿物的演化序列有关,具有重要研究价值。采用矿物学、微生物学和分子生物学等相结合的研究方法,有助于系统地研究微生物促进含钾硅酸盐矿物的风化并耦联碳酸化过程及其分子调控机制。研究证实,在纯培养条件下,微生物风化含钾矿物主要采用酸解、螯合、氧化还原等多种方式的协同作用,并可通过调控相关功能基因的表达来响应缺钾的环境以实现其对含钾矿物的有效风化,显然这有赖于微生物通过长期进化而形成的精细的分子调控机制。在土壤生态环境中,微生物对矿物风化的显著特征是该生态环境中微生物群落协同互作的群体作用效应。微生物碳酸酐酶参与的硅酸盐矿物风化伴随碳酸盐矿物的形成过程可能是个长期被忽视的地表碳增汇过程,对该问题的深入探索有助于进一步理解地质演化历史中微生物对碳素迁移转化的驱动机制。加入含钾硅酸盐矿粉的有机肥已经显示出其在土壤改良、作物生长和增加土壤碳汇等方面的正面应用效果,这为利用硅酸盐矿物的生物风化作用来延缓大气CO2浓度的持续升高提供了新的思路。介绍了有关微生物对含钾岩石生物转化释放钾素的分子机理及其碳汇效应方面的研究进展,以期抛砖引玉,推动该领域研究的快速发展。 相似文献
6.
矿物—微生物相互作用是地球表生环境下重要的地质作用类型,由于硅酸盐矿物的微生物风化影响着地球物质循环及地貌的形成和演变,尤其受到地质地球化学领域的关注。作为地球表层分布最广的硅酸盐矿物类型,长石在风化分解过程中,微生物通常会以流体模式、生物膜及真菌菌丝等方式与矿物表面发生作用。而长石在微生物作用下的分解机制主要包括质子交换和配体络合作用。微生物生理活动、微生物及代谢产物种类、生长条件,以及长石的种类、结构、成分及表面特征等均会影响其风化速率和风化程度。由于长石在硅酸盐矿物中的代表性,因此对长石—微生物作用模式、机理、影响因素等方面的研究,可以大大促进硅酸盐的微生物地质学的发展。 相似文献
7.
微生物对硅酸盐矿物风化作用研究进展 总被引：6，自引：1，他引：6
微生物对硅酸盐矿物风化的影响研究取得了一系列重要进展。在贫营养环境中,微生物风化硅酸盐矿物获取营养物质,加速了硅酸盐矿物的风化;由于微生物的作用,矿物的风化会不遵循正常的矿物化学风化序列,表现出稳定矿物比不稳定矿物更易风化的特征。微生物风化硅酸盐矿物时会在硅酸盐矿物表面留下痕迹,即富集或转移相应的元素和矿物,而且还能改变硅酸盐矿物的化学组成和结构。微生物的上述行为受营养基质含量、有机酸、生物膜、胞外聚合物以及氧化还原作用的影响。 相似文献
8.
在河口与边缘海区域,大量陆源风化产物的输入和强烈的有机物再矿化作用加速了自生硅酸盐矿物和碳酸盐矿物的生成,这一过程与陆地风化作用相反,被称为反风化作用(Reverse weathering)。反风化作用所导致的自生矿物形成通常在短时间内完成,被认为是平衡大气二氧化碳含量,控制海洋中元素平衡的重要过程。反风化作用的研究方法主要分为直接观察法和化学检测法,前者主要用于自生矿物的结构和元素组成的分析,后者则用于自生铝硅酸盐矿物等定量的研究。反风化作用对海洋环境中碳、硅、常量离子(F~-,Li~+,Na~+,K~+,Ca~(2+)和Mg~(2+)等)和金属元素(Fe,Mn和Al等)等的循环具有重要影响,并促使它们在海洋沉积物中长久埋藏。富含金属氧化物的风化产物的输入,大量易降解有机物和生物硅的沉降,强烈的再矿化作用和次氧/厌氧的成岩条件使得河口与边缘海区域成为反风化作用发生的主要场所。 相似文献
9.
硅酸盐细菌代谢产物影响斜长石风化作用的模拟试验 总被引：1，自引：0，他引：1
实验选用一株硅酸盐细菌,研究了实验条件下该菌株所产生的代谢产物对斜长石的分解与脱硅、铝的作用。通过检测不同风化培养基中代谢产物的种类与浓度、代谢产物与矿物相互作用过程中释放矿物中硅、铝的含量以及矿物晶体结构的变化,研究该菌株代谢产物对斜长石的风化过程和作用机制。结果表明:该菌株在不同的培养基中均会分泌氨基酸、有机酸与多糖等代谢产物,其中,在矿物风化培养基中菌株的代谢能力明显要高于无矿物培养基;各种代谢产物均对斜长石有一定的风化作用,多糖对矿物的分解作用最为明显,各代谢产物的混合物对斜长石的分解能力要高于各自代谢产物对矿物的分解能力。分析认为三种代谢产物的混合物在风化矿物的过程中具有一定的协同作用。 相似文献
10.
微生物对碳酸盐岩的风化作用 总被引：7，自引：0，他引：7
微生物-矿物相互作用可以促进许多表生生物地球化学反应过程,是表生地球化学研究的重要内容。通过综合岩石表面的微生物类群及其地质作用,分析碳酸盐岩微生物风化的各种现象,特别是微观尺度上的各种形态,阐述碳酸盐岩的微生物风化机制与风化产物,笔者提出微生物对碳酸盐岩风化的4种途径:(1)通过微生物在岩石表面和缝隙中生长,导致岩石表层发生生物溶蚀、生物磨蚀和生物钻孔作用,加速岩石风化进程;(2)微生物群体形成的钻孔网络可以增强岩石化学溶蚀的有效表面积并导致其表面强度减弱而促进机械侵蚀作用,微生物对周围岩石颗粒胶结结构的破坏、疏松作用也会导致岩石矿物颗粒的分解;(3)微生物的持水作用,微生物分泌的有机酸以及微生物呼吸所释放的CO2对岩表水分的酸化过程亦加速岩石矿物的分解;(4)微生物生长过程中从岩石内摄取营养元素和产生复杂的有机配体,能促进矿物元素的释放。文中提出在开展微生物对碳酸盐岩风化过程和机理研究的基础上,有必要引入微生物生物技术来综合开发本地低品位含钾磷矿产资源,加速岩溶地区山地土壤的形成与演化。 相似文献
11.
长江水系水文地球化学特征及主要离子的化学成因 总被引：5，自引：0，他引：5
在分析长江流域76个位点的水化学数据的基础上,运用吉布斯(Gibbs)图、三角图、主成分分析方法研究岩性对长江水表河水中离子化学特征的影响和流域的主要风化过程.结果表明,长江水系的主要离子化学特征受岩石风化作用的影响,其中碳酸盐和蒸发岩矿物对干流水系溶质的贡献率分别为43.6%和37.9%,而对支流水系溶质的贡献率分别为33.1%和39.1%.干流流域内主要的风化反应以白云石和方解石的溶解为主,而支流流域内C1~-/(Na~++K~+)接近1:1,体现出蒸发岩风化的显著特性.Si/K比值较低,表明长江流域内的风化反应是在表生环境中进行的,且产物是富含阳离子的次生矿物. 相似文献
12.
Reverse Weathering in River-dominated Marginal Seas 总被引：1，自引：1，他引：0
In estuarine regions and marginal seas, reverse weathering refers to the formation of authigenic aluminosilicate and carbonate minerals promoted by large inputs of terrestrial weathering products and intense remineralization of Sedimentary Organic Carbon (SOC), which is opposite to land weathering process. Compared with the process in open ocean, the formation of authigenic aluminosilicate and carbonate minerals caused by reverse weathering in estuarine regions and marginal seas is rather rapid, playing an important role in the maintenance of ocean acidity and elements cycles. At present, there are two research methods regarding the reverse weathering process, i.e., direct observation and chemical detection. The first method is used to study the structure and chemical composition of authigenic minerals and the second is mainly used to do quantified studies of authigenic minerals. The reverse weathering is very important to the cycles of Si, C, major ions (F-, Li+, Na+, K+, Ca2+ and Mg2+), and alkali metal cations (Fe, Mn and Al) in marine environments, which promotes the burial of these elements in marine sediments. Due to large inputs of weathering products rich in Fe, Mn and Al oxides, precipitation of labile OC and biogenic silica, intense remineralization process and suboxic/anoxic conditions, estuarine and marginal seas are suitable sites for reverse weathering studies. The reverse weathering studies in sub-tropical and temperate estuaries should be emphasized in the future. 相似文献
13.
In the Middle Atlas of Morocco, alkali basaltic flows record successive weathering phases during the Quaternary. In fresh basalt interior and intermediate external zones, the first weathering stage is characterised by glass dissolution and the formation of a Si-Al poorly-crystallised product. Advanced weathering phases are characterised by 10 Å halloysite, kaolinite and goethite, located within the primary minerals or as secondary products in fissures. Olivine and iddingsite are transformed into Si-rich goethite, plagioclase into halloysite and pyroxene into a mixture of halloysite + geothite. Dissolution of Ti-magnetite and ilmenite yielded Ti-rich products. In these conditions, the weathering of basalts and development of a soil matrix are accompanied by the elimination of certain chemical elements, such as Si, Ca, Na and K, and the concentration of Fe and Al. In the soil, clay minerals such as illite and vermiculite, do not have any genetic relationship with weathered basalt and were probably introduced externally. 相似文献
14.
Petrographic, mineralogical and chemical analysis of naturally weathered equilibrated ordinary chondrites collected from ‘ hot’ deserts and Antarctica has revealed striking similarities and also pronounced differences in weathering between the two environments. Terrestrial weathering in all meteorites studied is dominated by oxidation and hydration of Fe,Ni metal, producing Fe-oxides and oxyhydroxides that have partially replaced the metal grains and have also occluded primary intergranular pores to form veins. Troilite weathers readily in ‘ hot’ desert environments but undergoes very little alteration under Antarctic conditions. Most of the primary porosity of ordinary chondrites has been occluded by the time that ∼ 15 to 25% of the initial Fe0 and Fe2+ has been oxidised to Fe3+ in both environments. Results from modelling the volume changes upon alteration of primary minerals to a range of weathering products demonstrates that the primary porosity of most meteorites is sufficient to accommodate weathering products. Dilation of primary pores and brecciation, which has been observed in parts of some meteorites, will only occur if the meteorite is especially metal-rich, or has a low primary porosity. These weathering products are absent from recent falls but have formed in a fall after ∼ 100 yr of museum storage.Cl-bearing akaganéite and hibbingite are common weathering products in Antarctic finds but occur in abundance in only one ‘ hot’ desert meteorite, Daraj 014. The majority of Fe-rich weathering products in meteorites from both environments contain low, but variable concentrations of Si, Mg and Ca. In most meteorites a proportion of these elements are inferred to be present as a very finely crystalline mineral with a ∼ 1.0-nm lattice fringe spacing; where seen within intragranular fractures this mineral has a topotactic relationship with olivine and orthopyroxene. In the heavily-weathered Antarctic finds ALHA 78045 and 77002, Si is concentrated in cronstedtite, a Fe-rich phyllosilicate. An unidentified hydrous Si-Fe-Ni-Mg mineral or gel has also partially replaced taenite in ALHA 78045. In addition to Fe-rich weathering products, ‘ hot’ desert meteorites contain sulphates, Ca-carbonate and silica, whereas such minerals are largely absent from Antarctic finds. The abundance of silicate weathering products in Antarctic meteorites is unexpected and indicates that olivine and pyroxene undergo significant chemical weathering in these environments. As preterrestrial cronstedtite is abundant in CM2 carbonaceous chondrites, the Antarctic environment may be a powerful analog for aqueous alteration in the asteroidal parent bodies of primitive meteorites. 相似文献
15.
煤矸石-水相互作用的溶解动力学及其环境地球化学效应研究 总被引：17，自引：1，他引：17
党志 《矿物岩石地球化学通报》1997,(4)
煤矸石—水相互作用的溶解动力学及其环境地球化学效应研究党志（中国科学院地球化学研究所，贵阳５５０００２）关键词水—岩作用煤矸石地球化学动力学采煤矿区复垦环境效应收稿日期：１９９７－３－１０作者简介：党志男１９６２年生博士生环境地球化学煤矸石以其量多、... 相似文献
16.
铝土矿是化学风化作用的细粒终极产物,与强烈的化学风化作用密切相关。根据母岩的类别及作用过程,风化作用进一步分为铝硅酸盐岩强化学风化形成的红土化作用和碳酸盐岩强化学风化形成的钙红土化作用。在强烈的化学风化过程中,地表的原始沉积物(母岩)的原生矿物发生溶蚀、水解、水化、碳酸化、氧化,破坏原始的矿物结构,形成新的细粒矿物(主要是黏土质矿物)。在适合的地质条件下,持续的强烈化学风化作用会造成大部分活动的元素(如K、Na、Ca、Mg、Si)的流失与Al的残留富集从而形成铝土矿。现在观察到的沉积型铝土矿,虽然与古风化壳具有密切联系,但沉积型铝土矿多数是由沉积过程搬运到沉积盆地中所形成的强化学风化产物的沉积层,与古风化壳的残坡积层具有显著差别,只有少数工业价值不大(品位低、品质差)的残坡积相铝土矿。铝土矿含矿岩系的沉积环境与铝土矿(尤其是高品位、高品质的铝土矿)的成矿环境不尽相同。铝土矿主要形成于暴露于大气中的陆表环境(而非水下环境),由地下水淋滤作用形成(在渗流带由活动元素流失、Al等稳定元素残留富集而成)。本研究在铝土矿成矿作用分析等基础上,提出了以铝土矿沉积物等物源和沉积、成矿作用为依据的中国铝土矿床分类方案,包括原地或准原地残坡积物成因的红土型和喀斯特型,和异地物源沉积成因的沉积型。 相似文献
17.
Subaerial leaching process of sedimentary bauxite and the discussion on classifications of bauxite deposits 
下载免费PDF全文
下载免费PDF全文 Bauxite is the ultimate fine-grained products of chemical weathering,and thus it is closely linked with the intense chemical weathering. Based on variations of parent rock and weathering processes,the weathering products can be subdivided into laterite and terra rossa,of which the former is formed by weathering of aluminosilicates and the latter is produced by the weathering of carbonates. During the intense chemical weathering,minerals in original subaerial sediments(parent rocks)would suffer a series of processes(dissolution,hydrolyzation,hydration,carbonation,and oxidation)and be destroyed or transformed,leading to formation of new minerals. In the favorable environment,continuously intense chemical weathering would cause the loss of most mobile elements(e.g., K,Na,Ca,Mg,Si)and the enrichment of Al,resulting in the formation of bauxite. Although sedimentary bauxites are closely linked with the weathering curst,they show obvious differences in formation processes. Sedimentary bauxites are composed of intense chemical weathering products that are transported from outside of the basin and re-deposited in the basin,while most weathering crusts are transformed from saprolite and/or deluvium in-situ,and they can only form low-grade bauxites. Sedimentary environments also differ in bauxite ore layers and bauxitic claystone layers. Bauxite ore layers are formed in the subaerial environment and controlled by the leaching process of groundwater in the vadose zone. Based on the analysis of bauxitization,this study proposes to use multiple parameters,such as provenance,sedimentation and mineralization,to build the new classification of Chinese bauxite deposits. In this classification,lateritic and karstic types of bauxite deposits are autochthonous or parautochthonous saprolite and/or deluvium,while sedimentary type is dominated by heterochthonous provenance. 相似文献
18.
E.V. Dobrovolsky 《Chemical Geology》1987,60(1-4):89-94
The peculiarities of weathering processes involving duration, slow change of ambient conditions, isothermality as well as proceeding in open systems permit to study these processes in a steady-state approach (dCi/dt = 0, where Ci is concentration of intermediates; and t is time). The most typical quasi-stationary processes for a water-rock system are: (1) non-equilibrium step - surface reaction of primary-mineral dissolution; and (2) non-equilibrium step - secondary-mineral precipitation. These respectively determine two extreme mechanisms of mineral formation: (1) pseudomorphous replacement; and (2) dissolution-transfer-crystallization. Besides non-stationary weathering processes are known. It is the case when a process is controlled by diffusion through a layer of secondary minerals which have been deposited on the surface of the primary mineral. A mathematical model of weathering dynamics of feldspar with its metasomatic replacement by clay minerals is presented. Numerical simulation led to the prediction of mineral zonality development along the weathering profile at any time. 相似文献
19.
河南铝土矿矿物成因及其演化序列 总被引：2，自引：0，他引：2
[摘 要]豫西铝土矿是我国喀斯特型铝土矿的典型代表。本文选取豫西典型的喀斯特型铝土矿为研究对象,通过XRD 分析、扫描电镜-能谱分析、电子探针分析和差热分析多种手段,探测铝土矿的物质组成及其赋存状态,并且分析其矿物成因,总结矿物演化序列。研究显示,豫西铝土矿的主要矿物成分包括硬水铝石、伊利石、锐钛矿、高岭石、针铁矿、赤铁矿、金红石等。硬水铝石主体为简单结晶成因。伊利石主体为风化过程中产物,部分为后期硬水铝石硅质交代的结果。锐钛矿和硬水铝石同期结晶形成于还原环境下。大部分高岭石形成于陆源期风化阶段,少部分为后期硬水铝石硅化转变形成。针铁矿和赤铁矿形成于两个阶段,第一阶段为成矿前风化作用形成的铁质风化壳;第二阶段为铝土矿成岩晚期出现了一期铁质流体活动形成了大量的赤铁矿和针铁矿。重砂矿物金红石和锆石等主要是母岩风化作用的残留物。豫西铝土矿中矿物形成演化可归纳为如下五个阶段:陆源期、同生期、成矿期、成矿后期和表生期。 相似文献