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1.
华中陆壳高压变质带类白片岩的岩石矿物特征 总被引：4，自引：0，他引：4
华中陆壳高_压变质带以蓝片岩-榴辉岩-类白片岩三位一体为特征。类白片岩为一套富含高铝质矿物的岩石类型,分布在中元古界。主要岩石类型为刚玉蓝晶石岩、蓝晶石钠云母片岩,蓝晶石自云石英片岩和蓝晶石黄玉石英岩。变质矿物有蓝晶石、蓝刚玉、黄玉。钠云母、硬绿泥石和白云母等。类白片岩形成的温压条件为P=2000MPa,T=850—900℃,为高压条件下变质的泥质岩石。该类岩石与西德岩石学家Schreyer(1973)命名的典塑白片岩(蓝晶石+滑石)在矿物组合上略有不同,但其地质意义却很一致,都代表高压变质的泥质岩石,可作为地壳物质俯冲到地幔深度的指示剂,故称为类白片岩。 相似文献
2.
华中高压变质带中的蓝晶石黄玉岩系指一套富含铝质矿物的岩石,其矿物组合为蓝晶石+钠云母士白云母,蓝晶石+黄玉士石英,蓝晶石+蓝刚玉士硬绿泥石,蓝品石+白云母+石英等.化学成分富铝而贫镁。原岩为一套铝质粘土岩—砂岩.形成的温压条件为P=1.0～2.0GPa,T=650～900℃.其成分与典型的白片岩有所不同。故称为“类白片岩”.白片岩类是地壳物质俯冲到地幔深度的指示剂,从而证明华中高压变质带是古陆内板块裂开、碰撞、俯冲的产物。 相似文献
3.
一、岩石的物质组份及主要矿物特征蓝晶石产于蓝晶石岩、蓝儡石白云母石英片岩及含蓝晶石白云母石英片岩三个类型的岩石中。其中蓝晶石岩含蓝晶石50—90%,次要矿物为绢云母、褐铁矿、刚玉、金红石、榍石等。蓝晶石白云母石英片岩含蓝晶石10—30%,主要矿物为石英、白云母,少量矿物有赤铁矿、金红石、黄铁矿等,蓝晶石与白云母呈反消长关系。含蓝晶石白云母石英片岩中,蓝晶 相似文献
4.
罕见的超带状石榴石局部发现于Dora Maira地块南部厚约几米的层状含柯石英镁铝榴石蓝晶石多硅白云母白片岩中。白片岩包裹于正片麻岩之内,而后者则为被阿尔卑斯期改造的晚海西期花岗岩类。超带状石榴石与周围白片岩中的均匀镁铝榴石颗粒不同,它是由富铁铝榴石核和富镁铝榴石边构成的,前者含有许多矿物包体,而后者包体含量很少。富铁铝榴石核向富镁铝榴石边的转变是近于突变的,并与富含包体的结束位置一致。 相似文献
5.
柳树沟动力变质成因蓝晶石矿的成矿作用 总被引：1，自引：0，他引：1
一、前言蓝晶石类矿物※原料对发展现代工业和尖端技术具有重要意义。自1978年开始进行蓝晶石类矿物资源的普查工作以来,国内已发现多处蓝晶石产地。在成因上,它们几乎都属于前寒武纪区域变质类型,以片岩——片麻岩型为主,石英岩型较少,“伟晶岩型”罕见。据目前所知,吉林柳树沟石英岩型蓝晶石矿,是国内唯一属动力变质成因的蓝晶石矿。它在成因、成矿时代、原岩、变质矿物组合及成矿作用等方面,具有同区域变质类型明显不同的特点。这些特点,在已有矿床学和变质作用论著中,尚未得到明确阐 相似文献
6.
佛子岭群变质岩石学变质作用及时代的初步研究 总被引：7，自引：1，他引：7
佛子岭群是北淮阳地区分布较广的地层单位之五。主要岩石类型为长石石英岩、细粒石英岩、含蓝晶石英片岩和含石英白质大理岩，变质矿物在蓝晶石、石榴石、黑云母及白云母等。根据石榴石－黑云母矿物对计算温度约５２０℃，压力为０．３－０．５ＧＰａ。主变质作用年龄为３７８±２４Ｍａ。 相似文献
7.
佛子岭群是北淮阳地区分布较广的地层单位之一。主要岩石类型为长石石英岩、细粒石英岩、含蓝晶石英片岩和含石英白云质大理岩。变质矿物有蓝晶石、石格石、黑云母及白云母等。根据石榴石一黑云母矿物对计算温度约５２０℃，压力为０．３～０．５ＧＰａｋ。主变质作用年龄为３７８±２４Ｍａ。 相似文献
8.
这篇文章论述挪威白片岩的一种新产状,它成为第二种已知的产状。白片岩和斜方闪石一堇青石岩,在Modum杂岩中与钠长岩一起见于变质辉长岩和上壳岩之间的接触带中,这两种岩石都可以用M(F)ASH体系描述,而它们的形成是由于广泛的热液作用。全岩和矿物化学特征具有双峰式的Fe—Mg分配特征。滑石—蓝晶石片岩和贫铁的斜方闪石—堇青石岩构成—淡色岩群,而富铁的斜方闪石—堇青石岩则构成—暗色岩群。早期斜方闪石—堇青石组合分解为晚期滑石—蓝晶石组合表明P—T—t是等压或增压条件下的一种降温轨迹,温压范围约为600～750℃和6～8kb。滑石+钠长石±蓝晶石呈铝直闪石假象表明出的反应结构表现有过剩的钠长石,这些非等化学反应表明在地壳的深部存在一种活动的含钠流体。 相似文献
9.
五台山地区原金刚库组中含蓝晶石组合的变质作用及其意义 总被引：5，自引：8，他引：5
本文对山西五台山地区与超镁铁质岩密切共生的含蓝晶石的各类片岩进行了研究。研究发现，在蓝晶石铝直闪石片岩中存在一种特殊的冠状体结构，即蓝晶石和铝直闪石被它们之间内圈的十字石十刚玉十绿泥石和外圈的堇青石所包绕。这种特殊的反应边结构，说明岩石曾处于较高的压力条件下（０．９～１．４ＧＰａ），然后经历了明显的近等温的减压过程。其它类型的含蓝晶石片岩，也包含了高压变质矿物组合，并经历了同样的变质演化过程。这种演化历史与该区经历了古洋壳俯冲，消减，弧陆碰撞和伴随的迅速折返和抬升是密切有关的。 相似文献
10.
昌宁-孟连杂岩带澜沧岩群的岩石学、地球化学和变质演化及其对古特提斯构造演化的启示 总被引：3，自引：2，他引：1
云南三江地区昌宁-孟连杂岩带中的澜沧岩群内出露多种类型变沉积岩,主要包括含十字蓝晶石榴云母片岩、石榴云母片岩、硬绿泥石白云母片岩和绿泥蓝闪钠长片岩等。系统的岩相学观察、矿物化学和相平衡模拟研究结果表明,不同类型的变沉积岩保存了不同的变质演化历史。含十字蓝晶石榴云母片岩记录了自中温榴辉岩相降温降压至角闪岩相的退变质过程,峰期矿物组合为石榴子石+蓝晶石+多硅白云母+硬玉,变质温压条件为600～750℃和19～30kbar。通过石榴子石的X_(Prp)和X_(Grs),和多硅白云母的Si值限定石榴云母片岩的峰期矿物组合包括石榴子石+多硅白云母+绿辉石+硬柱石+钠云母,峰期温压条件为430～475℃和17～19.5kbar。硬绿泥石白云母片岩矿物组成包括硬绿泥石+多硅白云母+钠云母,然而峰期矿物组合则以多硅白云母+钠云母+纤柱石为特征,通过多硅白云母的Si值限定峰期温压条件约为300～330℃和17～19kbar。石榴云母片岩和硬绿泥石白云母片岩较为一致地记录了从峰期硬柱石蓝片岩相升温降压至绿帘石蓝片岩相的退变质过程。绿泥蓝闪钠长片岩主要通过变质反应和成因矿物学特征大致估算其温压条件约为430～520℃和9～11kbar。岩石地球化学性质研究结果表明,这些变沉积岩的平均化学成分与大陆岛弧、活动大陆边缘和上地壳沉积物成分较为接近,其原岩主要为一套成熟度较差的泥砂质岩类和少量的中基性火山岩。该泥砂质原岩的沉积物源以中酸性岩浆岩为主,存在不同程度古老沉积物的加入。构造判别图解表明,研究区样品主要形成于大陆岛弧或活动大陆边缘的构造背景。变质作用特征和原岩地球化学属性综合分析表明,昌宁-孟连杂岩带内大面积分布的澜沧岩群均发生不同程度的俯冲-消减过程,表现出多样的变质演化P-T轨迹的特征,表明澜沧岩群经历了多期/多阶段复杂的构造演化历史。 相似文献
11.
利用中子辐照改色法把天然无色黄玉改成蓝色黄玉,对天然黄玉和改色后的蓝黄玉分别进行了常规检测、Ｘ－荧光测试、紫外－可见光谱测试及红外光谱测试研究。结果表明：改色前后黄玉的比重、折射率、成分都没有明显的变化;其紫外－可见光光谱、红外光谱存在一定的差异。这些差异为鉴别天然黄玉与辐照改色黄玉提供了依据。 相似文献
12.
改色黄玉的红外光谱研究及其鉴别的数学模型 总被引：2，自引：0，他引：2
通过对天然黄玉与辐照改色黄玉的红外光谱研究发现,天然黄玉与辐照改色黄玉的透射红外光谱存在着一些差异,以这些差异为基础,利用数学方法把这些差异定量化,建立鉴别天然黄玉与辐照改色黄玉的数学模型,通过计算机编程,使宝石鉴定逐渐向自动化发展. 相似文献
13.
根据含黄玉岩石的矿物学、地质和地球化学以及黄玉中的流体包裹体特征研究，借鉴富F酸性岩体系的成岩成矿实验新成果，推出了新的黄玉成岩-成矿模式，力证黄玉是以富氟低熔岩浆结晶为主的多成因产物，不否定黄玉的交代蚀变和变质成因，认为盲目滥用和过分夸大变质（含交代）作用及其成岩、成矿的极端重要性和普适性不可取。 相似文献
14.
F. A. Letnikov 《Petrology》2008,16(4):319-334
The paper presents the first data obtained on topaz granites from dikes in columbite-bearing granites of the Kokchetav block, northern Kazakhstan. The columbite-bearing granites (398 ± 3 Ma, Rb-Sr method) compose large massifs and ubiquitously contain columbite as an accessory mineral in amounts from a few to a few dozen grams per ton. The topaz granites make up dikes up to 70–100 m long and 0.4–1.5 m thick, which have sharp contacts with the host granites. The composition of the topaz granites is as follows: albite ～50%, potassic feldspar ～24–26%, quartz ～20%, topaz 3–5%, biotite and muscovite ～1%. Topaz occurs in inner contact zones in the form of large (3–4 cm) crystals, which grew inward from dike contacts and is ubiquitous in the fine-grained groundmass as small (no larger than 0.05 mm) crystals. The ore minerals in the topaz granites (zircon, thorite, bastnaesite, Y-cerite, monazite, Y-fluorite, W-ixiolite, tantalite, columbite, and uraninite) developed as very small grains, which can be identified only under a microprobe and electron microscope. W-ixiolite was found only in topaz crystals. The topaz granites are rich in albite, contain Na > K and F concentrations from 0.2 to 0.97 wt %. Compared to the host columbite-bearing granites, the topaz granites are 10–15 times richer in Ta and Li, 3-8 times richer in Rb, Cs, Nb, Sn, F, and Be but 1.2–2 times poorer in U, Th, and REE. The columbite-bearing granites have Ta/Nb = 1: 20, while this ratio in the topaz granites is 1: 3, a fact highlighting the enrichment of the granites in Ta and their geochemical autonomy with respect to columbite-bearing granites. 相似文献
15.
晶体形态是描述矿物最直观的数据。本文对江西漂塘钨矿床中的５个黄玉晶体进行了晶体测量、投影、计算和实际晶体的立体图绘制，并对其形态特征进行了分析和总结。 相似文献
16.
Phase relations of F-rich Kymi equigranular topaz granite have been investigated experimentally at 100–500 MPa as a function
of water activity and F content. Fluorite and topaz can crystallize as liquidus phases in F-rich peraluminous systems, but
the F content of the melt should exceed 2.5–3.0 wt% for the crystallization of topaz. In peraluminous F-bearing melts containing
more than 1 wt% F, topaz and muscovite are expected to be the first F-bearing phases to crystallize at high pressure, whereas
fluorite and topaz should crystallize first at low pressure. Following reaction models the saturation of fluorite and topaz:
CaAl2Si2O8 (plagioclase) + 2[AlF3]melt = CaF2 (fluorite) + 2Al2SiO4F2 (topaz). The obtained partition coefficient for F between biotite and glass D(F)Bt/glass ranges from 1.89 to 0.80 (average value 1.29) and can be used as an empirical fluormeter to determine the F content of coexisting
melts. Combined petrological and experimental studies of the Kymi equigranular topaz granite indicate that plagioclase was
the liquidus phase at nearly water-saturated (fluid-saturated) conditions and that the F content of the melt was at least
2 wt%. The mean F content of natural biotite (3.92 wt%) suggests that the late-stage crystallization of biotite occurred in
melts containing about 3 wt% F. The early crystallization of biotite and the presence of muscovite in our experiments at 200 MPa
contrasts with the late-stage crystallization of biotite and the absence of muscovite in the natural assemblage, indicating
that crystallization pressure may have been lower than 200 MPa for the granite.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
17.
18.
The Mangabeira deposit is the only known Brazilian tin mineralization with indium. It is hosted in the Paleo- to Mesoproterozoic Mangabeira within-plate granitic massif, which has geochemical characteristics of NYF fertile granites. The granitic massif is hosted in Archean to Paleoproterozoic metasedimentary rocks (Ticunzal formation), Paleoproterozoic peraluminous granites (Aurumina suite) and a granite–gneiss complex. The mineralized area comprises evolved Li-siderophyllite granite, topaz–albite granite, Li–F-rich mica greisens and a quartz–topaz rock, similar to topazite. Two types of greisens are recognized in the mineralized area: zinnwaldite greisen and Li-rich muscovite greisen, formed by metasomatism of topaz–albite granite and Li-siderophyllite granite, respectively. Cassiterite occurs in the quartz–topaz rock and in the greisens. Indium minerals, such as roquesite (CuInS2), yanomamite (InAsO4·2H2O) and dzhalindite (In(OH3)), and In-rich cassiterite, sphalerite, stannite group minerals and scorodite are more abundant in the quartz–topaz rock, and are also recognized in albitized biotite granite and in Li-rich muscovite greisen. The host rocks and mineralized zones were subsequently overprinted by the Brasiliano orogenic event.Primary widespread two-phase aqueous and rare coeval aqueous-carbonic fluid inclusions are preserved in quartz from the topaz–albite granite, in quartz and topaz from the quartz–topaz rock and in cassiterite from the Li-rich muscovite greisen. Eutectic temperatures are − 25 °C to − 23 °C, allowing modeling of the aqueous fluids in the system H2O–NaCl(–KCl). Rare three-phase H2O–NaCl fluid inclusions (45–50 wt.% NaCl equiv.) are restricted to the topaz–albite granite. Salinities and homogenization temperatures of the aqueous and aqueous-carbonic fluid inclusions decrease from the topaz–albite granite (15–20 wt.% NaCl equiv.; 400 °C–450 °C), to the quartz–topaz rock (10–15 wt.% NaCl equiv.; 250 °C–350 °C) and to the greisen (0–5 wt.% NaCl equiv.; 200 °C–250 °C). Secondary fluid inclusions have the same range of salinities as the primary fluid inclusions, and homogenize between 150 and 210 °C.The estimated equilibrium temperatures based on δ18O of quartz–mica pairs are 610–680 °C for the topaz–albite granite and 285–370 °C for the Li-rich muscovite greisens. These data are coherent with measured fluid inclusion homogenization temperatures. Temperatures estimated using arsenopyrite geothermometry yield crystallization temperatures of 490–530 °C for the quartz–topaz rock and 415–505 °C for the zinnwaldite greisens. The fluids in equilibrium with the topaz–albite granite have calculated δ18O and δD values of 5.6–7.5‰ and − 67 to − 58‰, respectively. Estimated δ18O and δD values are mainly 4.8–7.9‰ and − 60 to − 30‰, respectively, for the fluids in equilibrium with the quartz–topaz rock and zinnwaldite greisen; and 3.4–3.9‰ and − 25 to − 17‰, respectively, for the Li-rich muscovite greisen fluid. δ34S data on arsenopyrite from the quartz–topaz rock vary from − 1.74 to − 0.74‰, consistent with a magmatic origin for the sulfur. The integration of fluid inclusion with oxygen isotopic data allows for estimation of the minimum crystallization pressure at ca. 770 bar for the host topaz–albite granite, which is consistent with its evolved signature.Based on petrological, fluid inclusion and isotope data it is proposed that the greisens and related Mangabeira Sn–In mineralization had a similar hydrothermal genesis, which involved exsolution of F-rich, Sn–In-bearing magmatic fluids from the topaz–albite granite, early formation of the quartz–topaz rock and zinnwaldite greisen, progressive cooling and Li-rich muscovite greisen formation due to interaction with meteoric water. The quartz–topaz rock is considered to have formed in the magmatic-hydrothermal transition. The mineralizing saline and CO2-bearing fluids are interpreted to be of magmatic origin, based on the isotopic data and paragenesis, which has been documented as characteristic of the tin mineralization genetically related to Proterozoic within-plate granitic magmatism in the Goias Tin Province, Central Brazil. 相似文献
19.
V. S. Balitsky D. V. Balitsky S. D. Balitsky C. Aurisicchio M. A. Roma 《Geochemistry International》2006,44(2):175-181
Silica and alumina transfer during the dissolution and growth of quartz, corundum, and topaz in supercritical aqueous fluids have been experimentally studied under a direct temperature gradient, and the possibility for growing of topaz monocrystals in them have been determined. It was demonstrated that the directions of silica and alumina transfer shows no unambiguous correlation with the composition, PT conditions, pH, and density of the fluids, and, in some cases, can be opposite. This defines simultaneous spatially associated or separated growth of quartz and topaz, as is often observed in camera pegmatites. Our experimental data made it possible to develop a reproducible seed growth of topaz monocrystals and to study their structure, morphology, and physical properties. 相似文献