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1.
国家珠宝玉石质量监督检验中心（NGTC）长石调查组在2009年对大量的＂西藏红色长石＂原料进行了宝石学性质、原石外围物质组成等实验室研究基础上,于2010年5月对西藏日喀则地区白朗县与江孜县交界的门措村、扎林村（E29°04′01.5″,N89°20′54.8″）进行了地质学、矿床学、地层学（包括地层剖面,洪积物、坡积物分析）及地貌学等一系列的实地考察,与村民访谈,观看收样过程及＂红色长石＂样品。考察及研究表明,所调查地点的＂红色长石＂是人工撒在地表及埋在浮土层中的,该观点支持了2009年实验室内研究的推断。  相似文献   

2.
近几年来,天津市和深圳市的多家珠宝公司曾对外宣称,他们在西藏地区发现了红色长石及其矿点,并标注＂拉雅神＂（lazasine）,＂西藏太阳石＂等名称进行宣传和销售。一般来说,在国际上,天然产出的红色长石（指红色斜长石）十分稀少,主要在美国的俄勒冈州被发现过。如果说中国西藏发现了红色长石矿点,自然是宝石界发现新资源的重要事件,  相似文献   

3.
近几年在国内外珠宝市场上出现了一种红色透明长石,其天然性引起了广泛的争议。采用常规的宝石学方法、LA—ICP—MS以及紫外-可见分光光度计等测试仪器研究了该红色长石样品的宝石学特征、化学成分及紫外-可见吸收光谱,旨在探讨其致色原因。结果表明,该红色长石样品属于中长石;与黄色长石样品相比,其化学成分中Cu的质量分数为739×10^-6～801×10^-6,远远高于黄色长石的（1．07×10^-6）,而其它微量元素的质量分数则无明显的差别,故认为Cu可能与其呈红色有关;紫外-可见吸收光谱结果显示,该红色长石样品在可见光区的吸收带主要位于566nm处,推测其可能与Cu对可见光的吸收有关。  相似文献   

4.
近期,国家黄金钻石制品质量监督检验中心对一串具蓝色晕彩的长石手链样品进行常规检测时,在长波紫外灯下多数珠子发中等强度的蓝白色荧光,且荧光在珠子中呈线状分布。为了对该长石样品进行准确定名,并探究其紫外荧光产生的原因,对其进行了常规宝石学检测、电子探针和红外光谱测试与分析。结果显示,该样品的折射率约为1.53,在显微镜下具有层状结构和针片状包裹体,结合其电子探针的分析结果,确定该样品为晕长石,即具有蓝色晕彩的钠长石;基于样品表面具有典型的＂蚯蚓行踪＂纹路、沿裂隙发出的紫外荧光及红外光谱下3 053,3 038cm^-1处的吸收峰,确定其为注胶处理的晕长石。  相似文献   

5.
为了进一步勘察中国西藏红色中长石的来源,一支国际考察队于2010年9月下旬前往西藏进行了实地考察。该队由日本宝石协会的Ahmadjan Abduriyim、  相似文献   

6.
红、黑双色火山玻璃作为天然玻璃中的少见品种,本文采用常规宝石学测试方法以及扫描电子显微镜（SEM）、红外光谱（FTIR）、X射线粉晶衍射（XRD）、拉曼光谱（LSR）及电子探针（EPMA）对该种火山玻璃的宝石矿物学特征及显微包裹体进行研究。结果显示,红、黑双色火山玻璃点测折射率为1.47,相对密度约2.36,摩氏硬度6～7,具有明显的流动纹理结构并广泛分布有孔径1～2μm的微气孔及因岩浆冷凝收缩所致的纳米级龟裂纹状结构缝隙。样品主体为玻璃态,红色部分含有大量点状及直径约1μm,长度5～25μm的赤铁矿针状包体,黑色部分则含有大量同尺寸的点状及针状磁铁矿包体并使其具明显磁性。此外,样品中还含有约5%斜长石微晶,晶粒尺寸约50～300μm,An约为28.4,另含有极少量尺寸约100μm的锆石包裹体。电子探针测试结果表明,红色及黑色区域玻璃态基质w（SiO2）均在75%以上,为典型的黑曜岩类火山玻璃。其中红色区域玻璃基质的w（SiO2）平均值为75.517%,黑色区域为77.621%,此外红区在FeO、K2O及Na2...  相似文献   

7.
南秦岭大型钡成矿带,钡矿物种类丰富。通过对南秦岭钡成矿带钡矿床中矿石和矿化围岩的电子探针研究,结合前人研究成果,发现南秦岭大型钡成矿带中钡主要以重晶石、毒重石、钡解石、菱钡镁石、钡长石、汉江石、安康矿、钡冰长石、钒云母等形式存在;硫化物以黄铁矿为主,并含有少量的针镍矿、闪锌矿、硫钒铜矿、蓝辉铜矿、斑铜矿。此外,还发现少量钒钛氧化物。在研究钡矿物化学组成的基础上,对毒重石、钡解石、菱钡镁石、钡长石、钡冰长石等钡矿物的成因进行了探讨。  相似文献   

8.
曹晖  李胜荣  姜文  李青  海东婧  王真 《地学前缘》2013,20(3):94-103
金青顶金矿是胶东东部一个特大型石英脉型金矿床,其探测深度已达约1 340 m,含矿石英脉的围岩主要为黑云二长花岗岩。文中对蚀变围岩中钾长石、斜长石和石英等主要矿物的结构与形态特征进行了详细观察及成因分析,发现热液成因钾长石大量存在于近矿围岩中,且深部钾长石化强度和范围都有加大的趋势,并大量出现由正长石和石英组成的团块状似伟晶岩。关于热液钾长石的形成温度,目前尚无可靠的测试数据。文中运用二长石温度计对蚀变岩中条纹长石平衡温度进行了估算,获得似伟晶岩中条纹长石平衡温度为433~482 ℃,而钾长石化叠加弱黄铁矿化花岗岩中条纹长石平衡温度为362~419 ℃。从似伟晶岩到钾长石化花岗岩、钾长石化叠加黄铁绢英岩化花岗岩中条纹长石平衡温度的渐次降低,反映了成矿流体与围岩反应逐渐弱化的特征。  相似文献   

9.
针对目前市场上出现的一些因优化处理而产生轻微玻璃残余物的天然红宝石,经适当浓度的氢氟酸(浓度23%)浸泡后,位于红宝石内裂隙和表面凹坑中的轻微玻璃态残余物被溶解,达到清理玻璃态残余物的目的,并利用电感耦合等离子体-原子发射光谱仪(ICP-AES)分析含玻璃材料的溶液中Si和Al的浓度分别为28.60μg/mL和2.795μg/mL,进而估算玻璃态残留物的损失量以判定热处理过程中非人为加入的玻璃态物质在红宝石中的充填程度。利用红外光谱仪对玻璃残留物清理前后的红宝石红外光谱进行对比研究得出:清理前,红外光谱显示在1 100~1 000 cm-1内有1个单峰宽谱带,谱峰为1 050 cm-1,是由νas(Si—O—Si)非对称伸缩振动引起的,表明残留物为非晶质体,750~600 cm-1之间位于744 cm-1的吸收峰为νs(Si—O—Si)对称伸缩振动引起;清理后,未检测到玻璃残余物特征的Si—O振动峰,仅具950~600 cm-1范围内的宽谱带,为刚玉Al—O基频振动谱带736、622 cm-1,体现晶质金属氧化物的特征,表明样品中玻璃态物质已被清除,实验后红宝石可被划归为经人工优化范畴。宝石显微镜下观察到清理实验后红宝石中原先被玻璃残余物所掩盖的显著内裂隙及表面凹坑。  相似文献   

10.
长石溶解模拟实验研究综述   总被引：2，自引：0，他引：2  
在综合分析前人研究成果基础上,对长石溶解模拟实验研究进行了综述.研究表明,长石溶解与其成分、结构、反应的温压条件以及流体性质等有关.在相同的温压条件下,3种长石的稳定性依次为:钾长石>钠长石>钙长石,且温度升高可加强长石的溶解能力,促进长石的溶解,而压力的变化对长石的溶解影响不大.长石的溶解速率在酸性区域随pH值增大而减小、在中性区域溶解速率低且受影响小、在碱性区域随pH值增大而增大.有机酸通过提供H+、络合金属元素来提高长石的溶解度.长石的溶蚀速率与颗粒的总表面积大小以及颗粒表面粗糙度有关,总表面积越大,表面越粗糙,则反应速率越快,而且溶液的矿化度越低越有利于长石的溶解.长石的溶解过程由表面反应和扩散反应所控制,描述长石溶蚀机理的模型主要包括:表面反应模型和淋滤层扩散模型.  相似文献   

11.
Polymict cristalline breccias are typical impact products of the Ries crater. They occur within the Ries crater (Appetshofen, Lierheim, Leopold Meyers Keller), on its rim (Maihingen-Klostermühle) and within the immediate vicinity of the crater (Itzing). Apart from very rare admixtures of sedimentary rock fragments the polymict cristalline breccias consist almost exclusively of fragments of various cristalline rocks, namely granites, gneisses and amphibolites. The petrographical and statistical investigations have shown that breccias from different localities have different composition. This reflects a possible difference in local compositions of the cristalline basement. The rocks in the breccias have been affected to various degress by shock metamorphism. The amphibolites could thus be shown to belong predominantly to stage I (diaplectic quartz and feldspar, 100–300 kb) and stage II (diaplectic quartz and feldspar glasses, 350–500 kb) whereas the granites and geisses can be attributed mostly to stage 0 (fractured quartz and feldspar, <100 kb) and stage I. This is in part the result of the bulk shock wave impedance of the rocks in question.Deformation structures resulting from shock metamorphism have been observed for the first time in sphene as well as in various planes of apatite.A large part of breccia rocks, which contain diaplectic quartz and feldspar glasses were altered into montmorillonite at a later date. The authigenic minerals were examined by x-rays and chemically by microprobe analysis.

Herrn Prof. Dr. W. von Engelhardt danke ich für Diskussion und Beratung. Dem Bundesministerium für Bildung und Wissenschaft sei für die finanzielle Unterstützung dieser Arbeit gedankt.  相似文献   

12.
Nodules (coarse-grain ??plutonic?? rocks) were collected from the ca. 20 ka Pomici di Base (PB)-Sarno eruption of Mt. Somma-Vesuvius, Italy. The nodules are classified as monzonite-monzogabbro based on their modal composition. The nodules have porphyrogranular texture, and consist of An-rich plagioclase, K-feldspar, clinopyroxene (ferroan-diopside), mica (phlogopite-biotite) ± olivine and amphibole. Aggregates of irregular intergrowths of mostly alkali feldspar and plagioclase, along with mica, Fe-Ti-oxides and clinopyroxene, in the nodules are interpreted as crystallized melt pockets. Crystallized silicate melt inclusions (MI) are common in the nodules, especially in clinopyroxenes. Two types of MI have been identified. Type I consists of mica, Fe-Ti-oxides and/or dark green spinel, clinopyroxene, feldspar and a vapor bubble. Volatiles (CO2, H2O) could not be detected in the vapor bubbles by Raman spectroscopy. Type II inclusions are generally lighter in color and contain subhedral feldspar and/or glass and several opaque phases, most of which are confirmed to be oxide minerals by SEM analysis. Some of the opaque-appearing phases that are below the surface may be tiny vapor bubbles. The two types of MI have different chemical compositions. Type I MI are classified as phono-tephrite ?? tephri-phonolite ?? basaltic trachy-andesite, while Type II MI have basaltic composition. The petrography and MI geochemistry led us to conclude that the nodules represent samples of the crystal mush zone in the active plumbing system of Mt. Somma-Vesuvius that were entrained into the upwelling magma during the PB-Sarno eruption.  相似文献   

13.
The short range distribution of interatomic distances in three feldspar glasses has been determined by X-ray radial distribution analysis. The resulting radial distribution functions (RDF's) are interpreted by comparison with RDF's calculated for various quasi-crystalline models of the glass structure.The experimental RDF's of the alkali feldspar glasses were found to be inconsistent with the four-membered rings of tetrahedra associated with crystalline feldspars; the structures of these glasses are probably based on interconnected six-membered rings of the type found in tridymite, nepheline, or kalsilite. In contrast, the RDF of calcic feldspar glass is consistent with a four-membered ring structure of the type found in crystalline anorthite. T-O bond lengths (T = Si,Al) increase from 1.60 Å in SiO2 glass [J. H. Konnert and J. Karle (1973) Acta Cryst.A29, 702–710] to 1.63 Å in the alkali feldspar glasses to 1.66 Å in the calcic feldspar glass due to the substitution of Al for Si in the tetrahedra] sites. The T-O-T bond angles inferred from the RDF peak positions are 151° in SiO2 glass (see reference above), 146° in the alkali feldspar glasses, and 143° in the calcic feldspar glass. Detail in the RDF at distances greater than 5 Å suggests that the alkali feldspar glasses have a higher degree of long range order than the calcic feldspar glasses.Assuming that the structural details of our feldspar glasses are similar to those of the melts, the observed structural differences between the alkali feldspar and calcic feldspar glasses helps explain the differences in crystallization kinetics of anhydrous feldspar composition melts. Structural interpretations of some thermodynamic and rheologic phenomena associated with feldspar melts are also presented based on these results.  相似文献   

14.
在山东新泰市新太古代泰山岩群变质岩系中,首次发现宝石级红刚玉,又称红宝石,商业名称暂定为＂泰山红宝石＂。红宝石产于鲁西地区新太古代二长花岗岩的壳源岩石包体之中,包体岩性以黑云更长变粒岩、黑云片岩、角闪石岩、斜长角闪岩、浅绿色含铬二云片岩为主,是新太古代古老地壳的深融残留;红刚玉与浅绿色含铬二云片岩关系密切,推测是新太古代变质岩中原岩残留斑晶矿物。  相似文献   

15.
A spinel ± amphibole ± feldspar bearing Iherzolites, a spinel ± amphibole ± feldspar bearing harzburgites, and a spinel ± amphibole ± phlogopite bearing wehrlites are metasomatized peridotitic mantle xenoliths from Ain Temouchent volcanic complex (North-West Algeria). These xenoliths are metamorphic/deformed rocks with a strong planar fabric typical of mantle tectonites. The wehrlites are not the result of a simple model of partial melting. The spinel ± amphibole ± feldspar bearing harzburgites and lherzolites exhibit asymmetric concave-shaped REE patterns. These indicate that an earlier partial melting event was followed by metasomatic processes. The wehrlites have higher REE concentrations and LREE/HREE fractionations, indicating a sequential evolution of wehrlites from previous refractory material with melting as an addition process. This process reflects the interaction of the lithospheric mantle beneath the Ain Temouchent area with basaltic melt. Metasomatism is expressed by the formation of amphibole, phlogopite, and increased abundances of clinopyroxene at the expense of orthopyroxene, in lherzolite and harzburgite. In the Ain Temouchent area, metasomatizing agents are Na-alkali silicates. The similarities observed between the glasses studied in this paper, and the basaltic host rocks of the Ain Temouchent area, may suggest a common mantle source, or with chemical similarities but with relatively different evolutions pathways. The formation of glass in wehrlites from the Ain Temouchent area has an origin formed by the breakdown of amphibole or phlogopite as a result of decompressional melting and production of silica-undersaturated glasses. The glass reacts with essentially orthopyroxene to produce silica-rich glasses. This study has contributed to highlighting a relationship between glass, and the processes that caused the formation of metasomatic phases.  相似文献   

16.
内蒙中部地区金的成矿类型有含金石英脉型、含金蚀变岩型、含金钾长花岗岩脉型、含金石英钾长石脉型及不整合面金矿型.迄今已探明赛乌素、十八顷壕、后石花、酒馆、柏树沟、大桦背和白乃庙等金矿.进而提出蚀变岩型、石英脉型及钾长石化地区的金矿找矿方向.  相似文献   

17.
贵州岩溶区红色风化壳是中国南方红色负化壳的重要组成部分，本文根据部分红色风化壳剖面野外特征、矿物学、地球化学及土壤物理学等的研究结果，对其物源及成因进行了探讨。各剖面，尤其邻近剖面显著的矿物学、地球化学差异排除了远程风成沉积物、火山灰、上覆或者高处碎屑岩层作为统一且重要物源的可能。极低的石英含量表明贵州常见的长石石英砂岩不是其主要物源，具有中稀土（MREE）富集的特征也排除了粘土岩、页岩作为主要物源的可能。风化壳剖面间的差异性均可从基岩酸不溶物的差异性得到很好解释，表明它们是下伏碳酸盐岩风化、酸不溶物（准）原地堆积的结果。部分剖面甚至显示了典型风化壳剖面的一些特征，具有正常风化序列的剖面结构特征。  相似文献   

18.
Abstract

A newly discovered, shoshonitic lava-hosted Pb deposit at Nariniya in central Tibet provides an excellent example to help improve our understanding of the linkage between post-collisional potassic magmatism and ore formation in Tibet. The Pb ores exist as veins or veinlets in NWW-striking fracture zones within the potassic lava (trachyte). The veins contain quartz, galena, pyrite, and sericite (muscovite) as well as minor chalcopyrite, sphalerite, calcite, and dolomite with sericitization, pyritization, and minor silicification. The 40Ar–39Ar plateau age of the hydrothermal muscovite is 37.95 ± 0.30 Ma, which represents the Pb mineralization age. This obtained age is indistinguishable, within analytical error, from the zircon U–Pb age of 37.88 ± 0.22 Ma for potassic lava. Therefore, the ore formation can be genetically linked to potassic magmatism. Galena has similar Pb isotopic composition to magmatic feldspar from the host lava, suggesting the derivation of Pb from the magmatic system. Previous studies have suggested that S- and ore-forming fluids are of magmatic origin. Published data show that the Nariniya volcanic rocks are acidic, shoshonitic, akakitic, peraluminous, and enriched in Sr–Nd–Pb isotopes. Thus, they are geochemically different from other potassic volcanic rocks (no adakitic affinity) in the North Qiangtang terrane, but similar to the 46–38 Ma high-K calc-alkaline peraluminous adakitic rocks in this terrane and the late Eocene Cu-generating potassic porphyries from the Sanjiang region of eastern Tibet. As such, the Nariniya potassic magma likely originated from melting of subducted continental crust, with or without interaction with the overlying enriched mantle. Such post-collisional potassic rocks in Tibet are thought to be potential targets for prospecting of both Pb–Zn and porphyry Cu ores. Note that other ore styles (in addition to the Nariniya ore style) may exist in the potassic volcanic districts of Tibet.  相似文献   

19.
陕北靖边波浪谷丹霞地貌区是近年来国内外地学界的新发现和持续关注点。论文通过野外地质调查、粒度分析,岩石地球化学分析等研究,探讨红色砂岩地球化学特征、沉积环境、物源性质等相关问题。研究表明:红色砂岩以中—细砂为主,SiO2和Al2O3含量之和在85%以上,沉积环境为河湖相,为水动力中等,水面较浅的河流入湖三角洲河口区地带,而不具有目前一些学者通过宏观观察提出的该砂岩为沙漠相沉积特征。沉积阶段气温较高,存在暖干与暖湿的多次变化。地球化学分析表明红色砂岩地球化学类型为长石砂岩和亚长石砂岩,物源可能来自于盆地内部隆起或再旋回造山带所提供的富石英质沉积岩。  相似文献   

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