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11.
玄武岩中刚玉巨晶的包体研究：Ⅰ.更长石包体的发现及意义 总被引：3，自引：0，他引：3
本文对山东昌乐碱性玄武岩中刚玉巨晶的更长石包体及同一地区产出的歪长石巨晶进行了电子探针、红外吸收光谱测定,讨论了更长石包体与刚玉巨晶、歪长石巨晶间的成因关系,认为刚玉巨品、歪长石巨晶以及玄武岩中的其他巨晶构成了一个结晶序列,歪长石相对较晚结晶。 相似文献
12.
Orthopyroxene-Corundum in Mg-Al-rich Granulites from the Oygarden Islands, East Antarctica 总被引：1，自引：0，他引：1
High-Mg–Al, silica-undersaturated metapelites from theOygarden Group of islands, East Antarctica, preserve clear evidencefor the stable coexistence of the assemblage orthopyroxene +corundum in natural rocks. The quartz-absent metapelite occursas pods and isolated layers within a high-strain zone relatedto deformation during the c. 0·93 Ga Rayner StructuralEpisode. Assemblages that include orthopyroxene, corundum, sapphirine,sillimanite, cordierite, garnet and kornerupine are developedacross a pre-existing compositional zoning, leading to contrastingmineral Fe–Mg ratios. The assemblage orthopyroxene–corundumis shown to exist in only a very restricted range of bulk compositionsand P–T histories. Simplified qualitative FMAS grids havebeen constructed for kornerupine-absent and -present systems,illustrating MAS terminations and divariant equilibria thathelp to describe the mineral assemblage and reaction history.Reaction textures that include coronas of sapphirine and sillimaniteseparating orthopyroxene and corundum, and symplectites of orthopyroxene+ sapphirine ± cordierite/plagioclase, orthopyroxene+ sillimanite ± cordierite/plagioclase and orthopyroxene+ sapphirine + sillimanite embaying garnet, imply a clockwiseP–T–t evolution. Conditions of P > 9–10kbar and T 相似文献
13.
郯庐断裂带中段第三纪玄武岩特征及与刚玉形成的关系 总被引：6，自引：0，他引：6
对郯庐断裂带中段第三纪玄武岩的岩石学特征、地球化学特征进行了研究。对火山岩系列及其类型进行了划分 ,并作了分类命名。探讨了玄武岩与刚玉形成的关系 相似文献
14.
F. L. Sutherland K. Zaw S. Meffre G. Giuliani A. E. Fallick I. T. Graham 《Australian Journal of Earth Sciences》2013,60(7):1003-1022
Gem corundum, a minor but persistent megacryst in east Australian basalt fields, is mined from some placer concentrations. Laser ablation, inductively coupled plasma mass spectrometry analyses and O isotope determinations on a colour range of corundum from different fields, show that chromophore (Fe, Cr, Ti, V) and genetic indicator (Ga, Mg, δ18O) values can distinguish corundum sources (magmatic, metamorphic and metasomatic) before basalt incorporation. They also characterise corundum groups from different fields. This identified two metamorphic groups, one carrying ruby at Barrington Tops, and a magmatic group distinct from those from other gem fields (lower Fe, northeast Tasmania; higher Fe, Yarrowitch). Ruby-bearing groups show clear provincial characteristics and include lower temperature spinel-facies groups (Barrington, Yarrowitch) and higher temperature garnet-facies groups (Cudgegong–Macquarie River). High Mg/Fe and Ni values in the latter approach those for corundum in diamond, and are a possible diamond indicator. The corundum derived from diverse fold-belt and felsic sources in underlying lithosphere forms a dataset for comparing corundum from other basalt fields. 相似文献
15.
利用电子探针、扫描电镜分析技术在产自山东碱性玄武岩的刚玉巨晶中发现了尖晶石族氧化物包体,并有许多刚玉、钛铁矿、高硅氧化物、辉石、长石、方解石等包体.这些包体矿物的化学成分明显与该地区相应的巨晶矿物不同,具有深源性的特征.刚玉巨晶具有世代现象,其生长具有明显的阶段性,是在一种高度演化的富含SiO_2岩浆中生成,生长过程极其复杂. 相似文献
16.
在佛经与我国史籍中均记载有一种名为＂火珠＂的宝石,但其宝石学成分究竟是什么,历来争论颇大。三国时期,＂火珠＂开始从外国进口,被帝王看作是祥瑞的标志。晋代时期其用于装饰皇太子的玉具剑。隋唐时期,其价值进一步提升,专用于装饰皇帝的玉具剑。自唐朝末年开始,＂火珠＂一词的宝石学意义逐渐减弱。探讨＂火珠＂有助于了解中国古代宝石的使用情况,对构建中国古代宝石学具有重要意义。从＂火珠＂的产地、颜色、稀有性等宝石学特征以及与出土宝石实物比照,对其成分进行了较详细的论证。结果发现,＂火珠＂是巴利文＂Phalika＂（＂颇黎＂）以及梵文＂Sphatika＂（＂塞颇胝迦＂）的意译。＂火珠＂也就是＂颇黎＂,并不是我国常见的水晶,最可能为无色刚玉。 相似文献
17.
钛矿资源主要类型为钛铁矿岩矿、钛铁矿砂矿、金红石矿。钛铁矿属于难熔矿物,一般不溶于硝酸、盐酸或王水。对于高品位钛铁矿,即使采用盐酸-硝酸-氢氟酸-高氯酸混合酸溶解样品,钛元素也易水解形成难溶的偏钛酸析出,常给分析带来很大困难。容量法和分光光度法等传统方法测定钛存在操作流程长、步骤多、效率低等不足。因此,选择合适前处理方法的同时将大型仪器分析方法结合起来,有利于提高钛铁矿分析的准确度和测试效率。本文建立了以2.0g过氧化钠为熔剂,使用刚玉坩埚在700℃熔融样品15min,热水浸取后盐酸酸化,用电感耦合等离子体发射光谱（ICP-OES）测定钛铁矿中的高含量钛元素的方法。实验中采用全程空白试液稀释定容标准溶液消除了钠基体影响,通过优化熔融温度和时间使样品分解完全,考察了过氧化钠用量来降低待测溶液中盐分以保证测定的稳定性,通过选择合适的分析谱线并采用背景扣除法消除光谱干扰。本方法检出限为0.0035%,测试范围为0.0066%～62.50%（均以TiO2含量计）;经钛铁矿国家标准物质（GBW07839、GBW07841）验证,相对标准偏差（RSD,n=12）为1.1%～2.1%,相对误差为-1.69%～1.11%。本方法应用于实际样品分析,相对标准偏差（RSD,n=12）均小于4%,TiO2分析结果与国家标准方法（硫酸铁铵容量法）一致。本方法有效解决了钛铁矿分解不完全及高含量的钛易水解的问题,实现ICP-OES对不同类型钛铁矿样品中钛元素的定量分析。 相似文献
18.
Granulite facies quartzites from the Ihouhaouene region, in the northern part of In Ouzzal, contain the assemblage corundum+quartz+magnetite together with hercynitic spinel+quartz+magnetite, sillimanite+quartz+magnetite and almandine-rich garnet+quartz+magnetite. Two types of corundum have been recognized: the first is primary and is found with quartz and magnetite only; the second type is found together with magnetite and chlorite rimming spinel as a fine-grained corona. The textures show that spinel-rich magnetite probably exsolved primary corundum, sillimanite, spinel and garnet during the cooling history. The secondary corundum formed later from the spinel already exsolved from magnetite. The secondary corundum is certainly metastable with respect to quartz. This may also apply for the primary corundum. However, given the high-temperature setting of this rock, it cannot be excluded that the stable contacts observed between primary corundum and quartz indicate equilibrium between the two phases. Taking into account the uncertainties in the thermodynamic data, the stability of this assemblage would imply that this part of In Ouzzal has recorded very high P–T conditions, above 1100°C at 12 kbar. 相似文献
19.
湖北英山刚玉矿物学研究 总被引：1，自引：0，他引：1
湖北英山刚玉矿床是本世纪五、六十年代发现的,由于多种原因未能对其进行研究和开发利用。本文系统地研究了英山刚玉矿物学特征,测定了各种物性和参数,观测了刚玉包裹体;并利用电子探针、粉晶Ｘ射线分析、可见光谱等现代测试手段,较详细地分析了刚玉的化学成分、晶体结构及光谱特征,并进行了热处理实验研究。指出湖北英山产出的刚玉颗粒大,晶形好,颜色较浅,可用热处理的方法改成蓝色、黄色、肉红色,但由于裂隙发育,包裹体 相似文献
20.
Mg-Al Sapphirine- and Ca-Al Hibonite-bearing Granulite Xenoliths from the Chyulu Hills Volcanic Field, Kenya 总被引：2，自引：0，他引：2
Basanites of the Chyulu Hills (Kenya Rift) contain mafic Mg–Aland Ca–Al granulite xenoliths. Their protoliths are interpretedas troctolitic cumulates; however, the original mineral assemblageswere almost completely transformed by subsolidus reactions.Mg–Al granulites contain the minerals spinel, sapphirine,sillimanite, plagioclase, corundum, clinopyroxene, orthopyroxeneand garnet, whereas Ca–Al granulites are characterizedby hibonite, spinel, sapphirine, mullite, sillimanite, plagioclase,quartz, clinopyroxene, corundum, and garnet. In the Mg–Algranulites, the first generation of orthopyroxene and some spinelmay be of igneous origin. In the Ca–Al granulites, hibonite(and possibly some spinel) are the earliest, possibly igneous,minerals in the crystallization sequence. Most pyroxene, spineland corundum in Mg–Al and Ca–Al granulites formedby subsolidus reactions. The qualitative P–T path derivedfrom metamorphic reactions corresponds to subsolidus cooling,probably accompanied, or followed by, compression. Final equilibrationwas achieved at T 600–740°C and P <8 kbar, inthe stability field of sillimanite. The early coexistence ofcorundum and pyroxenes (± spinel), as well as the associationof sillimanite and sapphirine with clinopyroxene and the presenceof hibonite, makes both types of granulite rare. The Ca–Alhibonite-bearing granulites are unique. Both types enlarge thespectrum of known Ca–Al–Mg-rich granulites worldwide. KEY WORDS: granulite xenoliths; corundum; sapphirine; hibonite; Kenya Rift 相似文献