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1.
堇青石是MgO-Al2O3-SiO2系统中的一个不一致熔融三元化合物,堇青石的多晶转变和有序-无序的结构变化一直是许多学者感兴趣的问题,并且作了比较深入的研究。  相似文献   

2.
吉林红旗岭铜镍硫化物矿床是我国第二大岩浆型铜镍硫化物矿床。为查明其岩浆来源、结晶温压条件等, 通过薄片鉴定及电子探针分析方法对红旗岭成矿岩体辉石化学成分特征进行了研究。结果表明:红旗岭单斜辉石全部为普通辉石, 斜方辉石均为古铜辉石;辉石成分变化较大, 普遍富镁贫铁, 总体上表现出低w(TiO2)、w(Al2O3)和w(Na2O)的特征;单斜辉石Di端元比例变化较大, 具有由富镁向富钙方向演化的趋势, 与世界上一些典型镁铁超镁铁岩体单斜辉石的演化趋势明显不同。红旗岭主要成矿岩体母岩浆属于拉斑玄武质岩浆, 为幔源岩浆, 分异程度较高。辉石温压计算结果表明, 红旗岭主要成矿岩体辉石结晶温度为1 100~1 250℃, 岩体形成深度为12.3~20.7 km。  相似文献   

3.
李哲 《地质科学》1979,14(2):151-156
引言戈斯(Ghose,S.)在测定斜方辉石的结构时,首次发现Fe2+离子择优占据M2晶位,而Mg2+离子择优占据M1晶位。这一事实,引起了矿物学家的极大注意。  相似文献   

4.
辉石是最重要的造岩矿物之一。无论是研究火成岩,变质岩,还是研究深部地质或月球岩石都离不开辉石的鉴定和研究。在工艺岩石学(例如铸石学)的研究中辉石鉴定问题也极为重要,尤其是X射线粉末法鉴定。因此,近五十年来很多人对辉石的X射线粉末图进行过研究。为了研究辉石类质同象对晶格常数的影响及其和成因的关系,各种辉石(主  相似文献   

5.
1963年6月我们在某盐湖湖滨工作时,发现一种透明无色-浅褐色具完好尖菱面体状晶形的矿物。加冷的稀盐酸溶解时,矿物剧烈发泡,并结晶出大量六方片状的硼酸晶体。经过矿物学、化学和X-射线的研究,确定该矿物和文献上所有已知的硼酸盐和碳酸盐矿物不同,是一种新矿物。其化学分子式为MgCa2[CO3|B2O5]·10H2O。  相似文献   

6.
祝时照 《地质科学》1975,10(2):150-165
一、引言铸石是利用天然岩石,如玄武岩、辉绿岩或某些工业废渣为原料,经配料或直接熔化、浇铸成型、结晶、退火而成的一种工艺岩石。它的矿物组分主要为单斜辉石,磁铁矿的量很少,在个别情况下可有少量橄榄石。从生产技术来看,铸石就是把天然玄武岩类所含的复杂矿物相用人工转变为单一矿物相,也就是将原料中大量的斜长石和相当量的橄榄石  相似文献   

7.
江苏东海县安峰山、平明山等地分布有新生代的火山岩,可作为铸石生产的主原料。但是原岩的化学成分并不能完全满足铸石生产的要求,需要加入其它配料。对该火山岩的命名,笔者建议定为橄响霞石岩。铸石化学成分的几个参数辉石质铸石主要由结晶相辉石和残余玻璃相组成。余硅系数K K=∑R~(+4)—∑R~(+2)—4∑R~(+1)式中:∑R~(+4),∑R~(+2),∑~(+1)分别为四价,二价,  相似文献   

8.
邝泰山  裴洁 《地质科学》1966,7(1):89-94
沉积的碳酸盐岩石主要是由方解石(CaCO3)和白云石(CaMg[CO3]2)的碳酸盐矿物组成。对于碳酸盐岩石中二氧化碳、氧化钙、氧化镁的测定,在例行的分析中,都是单独取样,分别以吸收重量法或容量法测定二氧化碳,以草酸铵-高锰酸钾容量法测定钙,而镁则根据 CO2与 CaO 的含量之差数来求得,或用氢氧化钡标准溶液使镁沉淀,于滤液中用盐酸滴定过量的氢氧化钡而测定镁。为了缩短分析时间,简化操作手续,节省试剂,作者提出了在以酸碱容量法测定 CO2后,在同一份样品中,以 E.D.T.A.络合滴定法进行钙和镁的连续测定方案。通过二年来的实践证明是完全可行的。它的特点是比较经济准确简便快速,因此具有一定的实际意义。  相似文献   

9.
二叠纪镁铁-超镁铁质岩体在北山造山带广泛分布,其中多发育铜镍硫化物矿化,并集中在新疆北山坡北和甘肃北山柳园地区。本文对柳园地区二叠纪骆驼山(283Ma)和西南山(277Ma)矿化岩体中早期结晶的造岩矿物开展矿物化学分析,并对甘-新北山地区矿化岩体的主要造岩矿物进行系统对比研究。骆驼山和西南山岩体主要由单辉橄榄岩、二辉橄榄岩、橄榄辉石岩、橄榄辉长岩和辉长岩组成,主要造岩矿物为橄榄石、单斜辉石、斜方辉石、斜长石和角闪石,及少量铬尖晶石和金云母。铬尖晶石Cr#值范围为52.2~70.4,TiO2含量为1.1%~4.0%,Al2O3含量为8.1%~18.9%。橄榄石Fo值范围为78~86,Ni含量为856×10-6~2121×10-6,Ca含量为71.3×10-6~720×10-6。斜方辉石主要为顽火辉石和少量古铜辉石;单斜辉石为透辉石和普通辉石,Mg#范围为86~88,Al...  相似文献   

10.
王松山 《地质科学》1983,(4):315-323
同位素地质年龄标准样的建立,是一项重要的基础工作,它在检查和比较各种实验流程,衡量各种定年方法的可信度,标定同位素稀释剂等方面,都是必不可少的。从1977年初开始,我国同位素地质标准样小组着手建立K-Ar法标准样。为了外检,笔者曾将ZBH-25黑云母、ZBJ角闪石带到澳大利亚国立大学地球科学院进行测定。这两个样品的K-Ar稀释法年龄、40Ar/39Ar坪年龄及40Ar/39Ar等时年龄的一致性表明,这些矿物结晶以后,未受过热的挠动,也不存在过剩氩,是作标准样的理想样品。本文还介绍样品中放射成因40Ar的析出特征,并指出40Ar可能有两种存在状态,它们各具不同的晶格能。  相似文献   

11.
Phase equilibria in the join CaMgSi2O6-CaFeAlSiO6-CaTiAl2O6 have been determined in air at 1 atm by the ordinary quenching method. Clinopyroxeness, forsterite, perovskite, magnetitess, spinelss, hibonite and an unknown phase X are present at liquidus temperatures (ss: solid solution). At subsolidus temperatures the following phase assemblages were encountered; clinopyroxeness+perovskite, clinopyroxeness +perovskite+spinelss, clinopyroxeness +perovskite+melilite (+anorthite), clinopyroxeness +perovskite+melilite+spinelss+anorthite, clinopyroxeness +perovskite+anorthite+spinelss, and clinopyroxeness +perovskite+anorthite+hibonite. At subsolidus temperatures the single phase field of clinopyroxeness extends up to 19 wt.% CaTiAl2O6. Even in the field of clinopyroxeness+perovskite, the TiO2 content in clinopyroxeness continues to increase and attains 9.2 wt.% TiO2 with 24.8 wt.% Al2O3. An interesting fact is that unusual clinopyroxenes which contain more AlIV than SiIV are present in the CaFe-AlSiO6-rich region. The liquid coexisting with pyroxene is richer in Ti, Al, and Fe3+ than the coexisting pyroxene. The clinopyroxenesss coexisting with liquid contain less TiO2, Al2O3 and Fe2O3 than those crystallized at subsolidus temperatures. The petrological significance of the join and the crystallization of Ti- and Al-rich clinopyroxenes are discussed on the basis of the experimental results of the join.  相似文献   

12.
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   

13.
The system CaMgSi2O6CaAl2SiO6CaFeAlSiO6 has been studied in air at 1 atm. The phase assemblage at subsolidus temperatures in the CaMgSi2O6-rich portion is Cpx + An + Mel and that in the CaMgSi2O6-poor portion Cpx + An + Mel + Sp. At subsolidus temperatures the sigle-phase field of clinopyroxene increases with an increase in the CaFeAlSiO6 component of the system. The Al2O3 content of clinopyroxene, however, continues to increase beyond the single-phase field and attains at least 16.04 wt.% Al2O3 with 3.9 wt.% Fe2O3. The stability field of fassaite in the system over a range of pressures and oxygen fugacities has been estimated from data in the literature as well as the present data. The CaFeAlSiO6 content of fassaite is dependent on oxygen fugacity, but is not influenced by pressure. The stability field is strongly influenced by oxygen fugacity at low and high pressure, and decreases with decreasing oxygen fugacity. Clinopyroxenes in both volcanic and metamorphic rocks from various localities, when plotted on the CaMgSi2O6CaAl2SiO6CaFeAlSiO6 triangle, show that there is no compositional gap between diopside and fassaitic pyroxene in metamorphic rocks, and that the fassaitic pyroxene in alkalic rocks becomes richer in both CaAl2SiO6 and CaFeAlSiO5 components as crystallization proceeds. These results agree with those obtained in the experimental study.  相似文献   

14.
We describe here high-field 17O magic-angle-spinning (MAS) and triple-quantum MAS (3QMAS) NMR spectra for several alkali silicate and Na, K, and Ca aluminosilicate glasses containing up to 10 wt.% water. The H2O site appears to have a large quadrupolar coupling constant, and its chemical shift increases from Na- to K- glasses, suggesting significant cation-H2O interactions. In 17O one-pulse MAS and 3QMAS and 27Al one-pulse NMR experiments, major differences were seen between spectra for anhydrous and hydrous calcium aluminosilicate glasses. The changes in the 17O MAS spectra can be explained by the addition of an H2O peak and to the disappearance of an Al-O-Al peak from the 17O NMR spectrum for the hydrous glass. The 27Al results are consistent with this interpretation.  相似文献   

15.
辉石作为一种主要造岩矿物广泛出现于许多岩类中,在基性火成岩中它更占有重要的地位。平衡条件下辉石的产出条件及其有关的相平衡关系,前人已有大量实验研究。  相似文献   

16.
The lower-crustal rocks of the Kohistan complex (northern Pakistan) are mostly composed of metabasic rocks such as pyroxene granulites, garnet granulites and amphibolites. We have investigated P–T trajectories of the relic two-pyroxene granulites, which are the protolith of the amphibolites within the Kamila amphibolite belt. Aluminous pyroxene retains igneous textures such as exsolution lamellae developed in the core. The significant amount of Al in clinopyroxene is buffered by breakdown reactions of plagioclase accompanied by film-like quartz as a product at grain boundaries between plagioclase and clinopyroxene. Distinct Al zoning profiles are preserved in pyroxene with exsolution lamellae in the core and in plagioclase adjacent to clinopyroxene in pyroxene granulites. In the northern part of the Kamila amphibolite belt, Al in clinopyroxene increases towards the rim and abruptly decreases at the outer rim, and anorthite in plagioclase decreases towards the rim and abruptly increases near the grain boundary between plagioclase and clinopyroxene. In the southern part of the Kamila amphibolite belt, Al in clinopyroxene and anorthite in plagioclase simply increase towards the margins of the grains. The anorthite zoning in plagioclase is in agreement with the zoning profiles of Ca-Tschermaks and jadeite components inferred from variations of Al, Na, Ti and Fe3+ in clinopyroxene. Assuming that the growth surface between them was in equilibrium, geothermobarometry based on Al zoning in clinopyroxene coexisting with plagioclase indicates that metamorphic pressures significantly increased with increasing temperature under granulite facies metamorphism. The peak of granulite facies metamorphism occurred at conditions of about 800 °C and 800–1100 MPa. These prograde P–T paths represent a crustal thickening process of the Kohistan arc during the Early to Middle Cretaceous. The crustal thickening of the Kohistan arc was caused by accretion of basaltic magma at mid-crustal depths.  相似文献   

17.
Tecto-aluminosilicate and peraluminous glasses have been prepared by conventional and laser heating techniques, respectively, in the CaO-Al2O3-SiO2 system. The structure of these glasses were studied using Raman spectroscopy, X-ray absorption at the Al K-edge and 27Al NMR spectroscopy with two different high fields (400 and 750 MHz). Raman spectroscopy and X-ray absorption are techniques sensitive to the network polymerization and, in particular, show different signal as a function of silica content. However, these two techniques are less sensitive than NMR to describe the local aluminium environment. For tectosilicate glasses, aluminium in five-fold coordination, [5]Al, was found and a careful quantification allows the determination of a significant amount of [5]Al (7% in the anorthite glass). The proportion of [5]Al increases for the peraluminous glasses with small amounts (<2%) of six-fold coordination, [6]Al. The presence of [5]Al agrees with previous observations of the existence of nonbridging oxygens (NBOs) in tectosilicate compositions. However, the proportion of [5]Al in the present study indicates that no major proportion of triclusters (oxygen coordinated to three (Si,Al)O4 tetrahedra) is required to explain these NBOS.  相似文献   

18.
室温常压下 Ca2+-Mg2+-HCO31--H2O 体系的试验研究   总被引:2,自引:0,他引:2       下载免费PDF全文
世界上很多海域中的现代碳酸盐沉积正在形成,如巴哈马滩、美国的佛罗里达湾、古巴的巴塔诺湾、中东的波斯湾等地,以及丹麦的某些近海地区。产于这些海域中的现代碳酸盐沉积物,其矿物组成主要是文石,其次为镁方解石,纯方解石较少,现代白云石沉积更为少见。我国的现代碳酸盐沉积见于南海诸岛及海南岛的沿海地带。作者曾利用粉晶照相鉴定了采自我国南海二十余种珊瑚、瓣鳃类、腹足类、有孔虫等现代海相生物壳体的物相,发现除有孔虫和海胆壳是由镁方解石构成外,其余生物壳体皆由文石构成。  相似文献   

19.
湘江铀矿产于湖南某地二迭系岩层中一铀矿床的氧化带中。对该铀矿床的成因目前有两种看法,一种认为是沉积变质型;另一种认为是沉积迭加热液型。湘江铀矿呈浅黄色的粉末状微晶集合体产于硅质岩的裂隙内或风化孔洞中。与铝铀云母,黄铁矿,石英,磷铝石等矿物共生。根据产地命名为湘江铀矿。  相似文献   

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