共查询到20条相似文献，搜索用时 15 毫秒
1.
Dušan Němec 《Mineralium Deposita》1990,25(4):297-303
In the central Iron Mountains the ore-mineralized deformation zones represent deep reaching faults which possibly reach the upper mantle. During geological history they were used by ascending magmas, fluids, and barren and ore hydrothermal solutions. It can be shown that the metasomatism provoked by acid fluids bears the character of greisenization. The type of the original greisenized rocks here can be determined on the basis of elements that were immobile during greisenization, especially Si, Ti, Sc and REE. After or even during greisenization, the metasomatic rocks were affected by shearing metamorphism corresponding in its PT conditions to the middle zone of the almandine-amphibolite facies. It was possibly in this period that the enigmatic skarn body of Samaov originated. Owing to its similarity to the dyke skarn of Kraskov, its similar origin could be assumed: the deposition of skarn minerals from circulating fluids, which were perhaps released during greisenization. 相似文献
2.
梅勇文 《吉林大学学报(地球科学版)》1987,(4)
云英岩化形成于富含挥发组份和氧逸度较高的酸性环境中,钾长石化形成于缺乏挥发组份的碱性条件下。富云母云英岩化和钾长石化为不同条件下的钾质交代蚀变作用,富石英云英岩化和硅化为不同条件下的硅质交代蚀变作用。单纯云英岩化或钾长石化,对钨矿化都不一定有利,而云英岩化外侧具钾长石化锒边,以及钾长石化外侧尚存在富石英云英岩化或硅化时,钨等矿化相对富集。 相似文献
3.
矿区出露地层为震旦一寒武系浅变质岩。钼矿床与燕山期高氟、高锂的细粒少斑黑云母花岗岩和花岗斑岩存在密切的空间、时间关系,钼矿化赋存在岩体的内外接触带,包括含辉钼矿萤石石英脉,含辉钼矿的裂隙脉和蚀变岩石（云英岩化）内浸染状产出的钼矿化,含辉钼矿的萤石石英脉是受NEE-SWW向和近SN向裂隙带控制,构成矿床的富矿体,矿区内的富矿作用为钾长石化、黑云母化、云英岩化、萤石化、硅化、绢云母化和绿泥石化,其中,与钼矿化关系密切的蚀变作用是黑云母化、云英岩化、萤石化和硅化。 相似文献
4.
The Yinyan porphyry tin deposit is a blind deposit associated with a small granite porphyry stock.The petrology and geochemistry of the Yinyan granite porphyry suggest that it is genetically of the transfor-mation type,emplaced at the late stage of fractional crystallization within a high-level magma chamber.Ore-forming fluids are derived predominantly from the granitic magma and they interact with the wall rocks intensely when finding their way upwards through the granite porphyry.From the lower part of the porphyry upwards the following alteration zones can be distinguished(a)slightly altered granite porphyry (with weak potash feldspathization),(b)protolithionite-quartz greisenization zone,(c)to-paz-quartz greisenization zone,(d)senicite-quartz sericitization zone,and （e）silicification zone (quartz core at the surface).Tin mineralization is related to greisenization,especially to topaz-quartz greisenization.Rock and ore-forming temperatures and oxygen fugacities are estimated,respectively.There are significant differences in many aspects between the Yinyan porphyry tin deposit and volcan-ic-subvolcanic porphyry tin deposits. 相似文献
5.
湖南上堡矿区钨锡矿成矿条件及找矿前景分析 总被引：1，自引：0，他引：1
上堡矿区出露地层有石炭系和二叠系,壶天群及栖霞组的灰岩、白云质灰岩化学性质活泼.W、Sn含量较高;区内的燕山早期黑云母花岗岩呈岩株或岩枝状产出,岩石具钠长石化和云英岩化,微量元素丰度值高;花岗岩体顶面的洼部构造很发育,规模大,是有利的成矿空间;围岩蚀变强烈,以矽卡岩化为主;W、Sn等元素的土壤异常围绕岩体分布,并且强度大,范围广;经钻探揭露,在接触带上有具工业意义的矽卡岩型钨锡矿体.通过分析,认为上堡矿区成矿地质条件优越,具有大型规模钨锡矿找矿潜力. 相似文献
6.
《International Geology Review》2012,54(7):1279-1293
Greisenization does not occur apart from ore bodies associated with the Kounrad granite massif. Primary minerals in granite altered and replaced during greisenization are quartz, feldspars, biotite, sphene, ore minerals, and apatite. Zircon, cyrtolite, and monazite are virtually unaffected by greisenization. Greisen-introduced minerals are muscovite, rutile group minerals, pyrite, fluorite, topaz, and molybdenite. Greisenization of Kounrad granite massif resulted in addition of more material than leached in all levels except at the base of vein zones. The excess of addition over leaching in middle and upper levels is mainly associated with upward migration of material. The value of total and individual factors of addition and leaching depends primarily on original rock composition more so than original porosity and rock structure. --R.M. Hutchinson. 相似文献
7.
广东莲花山斑岩型钨-金矿床蚀变类型可以分作钾化、云英岩化、绿泥石化、绢云母化和青盘岩化。不同原岩不同类型蚀变岩元素质量得失的定量计算结果表明,Th、TiO2、Al2O3、P2O5、Ta和Hf等在蚀变矿化过程中基本表现出惰性特征,质量得失较少,主元素在岩石中含量的变化主要受原岩类型的影响,其次受到蚀变作用类型的影响,成矿元素及与其有关的其他微量元素在蚀变岩中则主要表现出较大程度的富集。稀土元素在蚀变矿化过程中迁移作用不明显。本文结合蚀变矿化的地质特征及镜下观察结果对不同蚀变带中元素质量得失作了详细解释。 相似文献
8.
9.
Yu. A. Popova S. S. Matveeva A. Yu. Bychkov M. E. Ternopol’skaya Ya. V. Bychkova 《Geochemistry International》2017,55(2):211-217
The paper reports data on concentrations of lanthanides in rocks, fluorite, and wolframite from the Spokoininskoe greisen deposit in eastern Transbaikalia. Lanthanide concentrations in the ore-forming fluid are calculated using mineral/fluid distribution coefficients. The data on REE are consistent under the assumption of a single, but evolving, genetic source. The REE concentrations are similar for rocks variably affected by greisenization and are controlled by the solubility of monazite contained in the granite. The younger quartz–albite–muscovite veins and segregations contain elevated concentrations of LREE, which is explained by an increase in the monazite solubility in alkaline solutions during the late evolution of the fluid. 相似文献
10.
海南省罗葵洞钼矿围岩蚀变找矿标志 总被引：1，自引：0，他引：1
海南省罗葵洞钼矿是一处特大型斑岩型钼矿床,赋存于陆相火山岩与隐伏似斑状花岗岩接触界面及其外围,呈隐伏状产出,地表很难见到钼矿化露头.矿区最常见的蚀变是硅化和黄铁矿化,其次有钾化、绢云母化、绢英岩化、云英岩化、伊利石-水白云母化、黑云母化、绿帘石化、次闪石化、绿泥石化、碳酸盐化等,局部尚有叶腊石化、萤石化.其中硅化、钾化、绢英岩化、云英岩化与钼矿成矿关系密切.据初步研究,该区蚀变从火山口相中心,由内向外大致可分为不十分明显的4个蚀变带：强硅化蚀变带、硅钾蚀变带、硅化蚀变带、绿帘石-绿泥石化带.在详查工作中根据面形硅化细脉带,可以确定矿化范围,钾化强烈发育地段为钼矿富集部位. 相似文献
11.
Ing. Dušan NŘmec 《International Journal of Earth Sciences》1986,75(3):685-692
Intercalations of muscovite-quartz rocks have been investigated in leucocratic orthogneisses of the Svratka crystalline complexes (western Moravia). General characteristics for distinguishing apogranite greisens affected by regional metamorphism from metapelitic mica schists are given. The regionally metamorphosed greisens at Jimramovské Paseky are described in greater detail. — The greisens originated through greisenization of paraschists and afterwards affected by regional metamorphism can not be identified unequivocally due to lack of precise knowledge of their pregreisenization starting material. 相似文献
12.
《International Geology Review》2012,54(10):1144-1153
The geochemical features of hydrothermal-pneumatolytic rare element deposits are discussed on the basis of a natural connection between high temperature metasomatism phenomena and concentration processes of some rare elements. Two kinds of metasomatic processes are most interesting from the view-point of rare elements (albitization and greisenization). Li and Rb are concentrated in zinnwaldite-bearingalbitized granites and greisens. Nb, Ta (in columbite, pyrochlore, microlite, hatchettolite), Zr (in malacone zyrtolite), Be (beryl) are concentrated in albitized and greisenized granites. The beryllium deposits are closely connected with greisens of different composition, and quartz-greisen veins. The fluorite-bearing metasomatic rocks among carbonate rocks are characterizedby accumulations of Be (chrysoberyl, phenacite, taateite, sianhualite), Li (Li - margarite), Sn (cassiterite). The character of postmagmatic alterations of intrusive and wall rocks is a valuable indicator of the possibility of concentration of different rare elements.—Auth. English Summary. 相似文献
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14.
新疆贝勒库都克钾长花岗岩交代蚀变及锡矿化特征 总被引：2，自引：0，他引：2
贝勒库都克钾长花岗岩是一个富含Sn、As和F的岩体,具同熔型特征,是形成贝勒库都克锡矿的母岩.在岩体形成的后期,经历了钾化—钠化—云英岩化三个交代蚀变阶段.Sn、As等成矿、伴生元素的析出和富集发生在钠化和云英岩化两个阶段,形成了一定规模的锡矿床. 相似文献
15.
开展火烧岩烧变温度的识别对于火烧岩的形成及演化具有重要的指导意义。基于热Kaiser效应,通过火烧岩在热处理过程中的声发射累计能量以及参数RA(上升时间/振幅)和AF(平均频率)值的变化,对陕北神木张家峁火烧岩的阈值温度进行了预测。结果表明:火烧岩热声发射特征能有效识别火烧岩烧变温度,与火烧岩经历温度的岩相学分析基本一致;研究区火烧岩存在显著的地层烧变温度梯度,第1—第5层岩石烧变阈值温度逐渐升高,对于第6层和第7层岩石,最高温度超过700℃,对于第8层岩石,阈值温度为245℃;当热处理温度较低时,岩石内部沿晶拉张裂纹发育,超过600℃后,穿晶剪切裂纹所占比例开始增加,声发射信号出现二次增长,同时声发射出现平静期,累计能量曲线出现多个平台。火烧岩烧变温度的识别,对于煤矿防治水及围岩稳定性研究等具有重要的现实意义。 相似文献
16.
莲花山斑岩型钨－金矿床蚀变类型可以分作钾化、云英岩化、绢云母化、绿泥石化和青盘岩化。矿化表现为黑钨矿化、白钨矿－硫化物矿化、多金属硫化物矿化及黄铁矿化。蚀变在水平和垂向上具有分带性。由内向外由钾化向云英岩化、叠加蚀变带、绿泥石化＋绢云母化、青盘岩化转化。由浅向深，钾化增强，云英岩化减弱，被叠加蚀变带和绿泥石化及绢云母化所代替。矿化由内向外表现为由黑钨矿化向白钨矿化、多金属硫化物矿化、黄铁矿化转变，由浅向深由钨矿化转变为金矿化及多金属硫化物矿化。与典型斑岩型矿床蚀变分带对比，莲花山斑岩型矿床不同原岩类型蚀变特征变化较大，矿化则表现出富钨、金贫铜及钨金共同产出的特征。 相似文献
17.
南岭区域不同时期花岗岩体及与其有关的稀有金属矿床的形成,除了受区域混合岩化作用以及区域花岗岩浆分异演化作用的制约外,还受到遍布于南岭区域的每一个多期多阶段复式花岗岩体的自身分异演化作用的深刻的影响。在那些复式岩体中,只有在岩体分异演化的晚期阶段,才会出现稀有金属花岗岩母岩。现仅将本区域复式岩体和成矿母岩的分异演化及其与成矿作用的关系论述如下。 相似文献
18.
井筒自循环技术是开发干热岩地热的一种新技术,它采用油管和套管组成的U形通道作为换热器,目前对该项技术的现场和室内试验研究尚不够。文章建立了一个实验室规模的模拟装置来模拟干热岩局部井筒自循环的热交换过程,以水作为换热介质,进行一系列室内试验,对换热的影响因素及换热参数进行研究。试验结果表明:具有较大采热能力和热容量的花岗岩在高温下具有较高的采热速率;较高的注水速率会产生较高的采热速率,但出口温度会降低,因此,应慎重选择较高出口温度和较高采热量之间的平衡。相似性分析表明,876 m长的垂直井在602.8 m3/d的注入速率下,可从150 ℃的干热岩中获取的采热量高达565 kW,该结果与现场实测数据很接近,可以证明相似性分析结果的合理性。建立的模拟装置及试验原理也同样适用于“取热不取水”的中深层同轴套管式地埋管换热技术,可以为中深层地热开发研究和实际应用提供一定的参考。 相似文献
19.
The chondrite-normalized rare earth element (REE) patterns of whole rock samples from evolved granitic systems hosting rare metal deposits sometimes show a split into four consecutive curved segments, referred to as tetrads. In the present contribution, a rigorous statistical method is proposed that can be used to test whether geological significance should be attributed to tetrads that are only of limited size. The method involves a detailed evaluation of element and sample specific random and systematic errors that are constrained on the basis of independent repeated preparations and analyses of sample and reference materials. Application of the proposed method to samples from the granite-hosted Zinnwald Sn-W deposit, Germany, revealed that at least two tetrads in normalized whole rock REE patterns have to be analytically significant to rule out that fractional crystallization led to the unusual behavior of the REEs. Based on the analysis of altered albite granite and greisen samples from the endocontact of the Zinnwald granite massif, it is demonstrated that the lanthanide tetrad effect is responsible for the formation of the convex tetrads. Geological and petrological evidence suggests that the tetrads in the samples developed prior to greisenization and related cassiterite precipitation. In contrast to the endocontact samples, the rhyolitic wall rocks are typified by normalized REE patterns having tetrads that are variable in size and frequently close to the limit of analytical significance. The sizes of the tetrads apparently correlate with the intensity of albitization, but show no relation to subsequent alteration processes including greisenization and low-temperature argillization. This observation proves that curved segments in normalized whole rock REE patterns can be introduced during hydrothermal fluid-rock interaction. 相似文献
20.
A.M.R. Neiva 《Chemical Geology》1974,13(4):295-308
Greisenization of a muscovite-biotite albite granite of Alijó-Sanfins, northern Portugal, is studied for both major and trace elements. The principal tin-tungsten mineralization of the region is connected with this granite and the greisenization is accompanied by an increase in Cl, F, W, Nb, Sn, Pb and Rb. Cassiterite is the main carrier of Sn. Muscovite is the concentrator of Cl and F. The muscovite of the greisenized granite contains more Cl, F, W and Nb than the muscovite of the parental granite, but the former contains less Sn. Sn content of the muscovite of the greisenized granite is higher than that of the biotite of the parental granite; W content is similar or higher.When the greisenization is accompanied by albitization, the oxides and trace elements behave in a similar way to that found only with greisenization, except that there is a decrease of Ni and Rb. Li, Zr, Sr, Ba and Rb decrease as albitization increases. 相似文献