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1.
Geochemical patterns for elements, such as Sn, W and Au, present in drainage sediments as resistate heavy minerals are often erratic and difficult to interpret. To investigate the source of these problems and develop methods of eliminating them we have compared the behavior of Sn, present as cassiterite, and associated pathfinder elements downstream from a small primary Sn deposit in Perak, Peninsular Malaysia.Dispersion trains for the pathfinder elements are characterized by smooth decay patterns and differences in concentrations between high- and low-energy environments, characterized by coarse-and medium-grained sands respectively, are not significant. In contrast, Sn (and magnetite) concentrations are extremely erratic with significantly higher concentrations in high- compared to low-energy environments. As a result the dispersion train for Sn exhibits no regular decay pattern away from its source. These findings suggest that the action of the stream is analogous to that of sluice box, with light minerals being winnowed away and cassiterite, together with magnetite, accumulating. For all but the finest sizes this process, which is most efficient in high-energy environments, causes considerable local variability in Sn content of the sediments. However, because the hydraulic behavior of cassiterite and magnetite is similar, but magnetite is not associated with the primary mineralization, the Sn/magnetite ratio can be used to eliminate Sn anomalies resulting from local variations in hydraulic conditions.The concept of hydraulic equivalence of cassiterite and magnetite was extended to examining the relationship between Sn and different size fractions of the light minerals that constitute the bulk of most sediments. Greatest contrast is obtained when the Sn content of the −270 mesh (−53 μm) fraction is re-expressed as its hydraulic equivalent concentration in −65 + 100 mesh (−212 + 150 μm) material.For exploration purposes it is concluded that: (1) providing cassiterite is present in the fine size fractions, sampling of this material will reduce hydraulic effects, thereby reducing data variability, and can also increase the length of the anomalous dispersion train; and (2) hydraulic effects can also be reduced by re-expressing Sn concentrations as ratios to magnetite (provided this is not associated with the primary Sn mineralization) or a hydraulically equivalent size fraction of the light minerals that constitute the bulk of the sediment. Similar principles probably apply to the interpretation of geochemical data for other elements dispersed in drainage sediments as heavy minerals; this warrants further investigation.  相似文献   

2.
At Segura, granitic pegmatite veins with cassiterite and lepidolite, hydrothermal Sn–W quartz veins and Ba–Pb–Zn quartz veins intruded the Cambrian schist–metagraywacke complex and Hercynian granites. Cassiterite from Sn–W quartz veins is richer in Ti and poorer in Nb and Nb+Ta than cassiterite from granitic pegmatite. Wolframite from Sn–W quartz veins is enriched in ferberite component. The Sn–W quartz veins contain pyrrhotite, arsenopyrite, sphalerite, chalcopyrite, stannite, matildite and schapbachite and the Ba–Pb–Zn quartz veins have cobaltite, pyrite, sphalerite, chalcopyrite, galena and barite, which were analyzed by electron microprobe. The presently abandoned mining area was exploited for Sn, W, Ba and Pb until 1953. Stream sediments and soils have higher concentrations of metals than parent granites and schists. Sn, W, B, As and Cu anomalies found in stream sediments and soils are associated with Sn–W quartz veins, while Ba, Pb and Zn anomalies in stream sediments and soils are related to Ba–Pb–Zn quartz veins. Sn, W, B, As, Cu, Ba, Pb and Zn anomalies in stream sediments and soils are also related to the respective old mining activities, which increased the mobility of trace metals from mineralized veins to soils, stream sediments and waters. Stream sediments and soils are sinks of trace elements, which depend on their contents in mineralized veins and weathering processes, but Sn, W and B depend mainly on a mechanic process. Soils must not be used for agriculture and human residence due to their Sn, B, As and Ba contents. Waters associated with mineralized veins were analyzed by flame atomic absorption spectroscopy (FAAS) and ICP-AES have high As, Fe and Mn and should not be used for human consumption and agriculture activities. The highest As values in waters were all related to Sn–W quartz veins and the highest Fe and Mn values were associated with the Ba–Pb–Zn quartz veins. No significant acid drainage was found associated with the old mine workings.  相似文献   

3.
来利山锡矿床与小龙河锡矿床是滇西地区典型的云英岩型锡矿床。为揭示它们在成因上深层次的差异性,对来利山锡矿和小龙河锡矿的锡石进行了电子探针成分分析、镜下观察以及成矿环境对比分析。结果表明,锡石中的铁多以Fe~(3+)的形式与Sn~(4+)发生类质同象,氧逸度越高,锡石中Fe~(3+)越多,宏观上表现为锡石的颜色越深。来利山矿区锡石中Fe含量明显低于小龙河矿区,且锡石颜色明显比小龙河矿区颜色浅,反映了来利山锡矿成矿环境相对开放,成矿流体氧逸度偏低,流体中Sn络合物迁移能力较强,在花岗岩体外接触带的围岩裂隙中形成外云英岩型锡矿床;而小龙河锡矿成矿环境相对封闭,成矿流体氧逸度偏高,流体中Sn络合物迁移能力较弱,多在花岗岩体顶部的构造裂隙中形成内云英岩型锡矿床。  相似文献   

4.
The Southeast Asia Tin Research and Development (SEATRAD) Centre initiated a project to study the relationship between Sn mineralization and geochemical anomalies in non-residual overburden at and around Tebrong in the Lenggang district of Eastern Belitung, located about 400 km north-northeast of Jakarta. Belitung island, with a land surface area of about 5000 km2, forms the easternmost expression of the Southeast Asian tin belt.There is essentially no outcrop, only minor scattered float in the study area. Drainage is very poorly developed and consists of several small creeks. The climate is tropical with a mean daily maximum temperature of 33°C, and an average annual rainfall of about 2000 mm. The watertable is at approximately 5 m depth, depending on seasonal rainfall and local elevation.The oldest rock sequence in the study area is a Triassic metasediment consisting of sandstone, phyllite, claystone, mudstone and quartzite. These rocks are intruded by Triassic granitic plutons. The Tebrong area is underlain by low-grade Sn mineralization consisting of swarms of <0.5-cm-thick subvertical quartz - tourmaline - kaolinite - chlorite - cassiterite veins. In general, cassiterite is present in quartz veins which occur as fracture fillings in the country rocks. These rocks are overlain by Quaternary cassiterite-bearing alluvium (kaksa). Residual lag kaksa typically occurs on Belitung.In the central part of the study area where there is a thick alluvial cover, the soil is mostly transported material. Surface soil geochemically anomalies are absent, but near bedrock, weak anomalies can delineate placer concentration of Sn.Based on the findings of the initial survey, it can be concluded that the distribution of Sn in non-residual overburden does not reflect bedrock Sn distribution. However, geochemical soil profiling, using a motorized auger, can be usefully employed to delineate target areas for further exploration for placer Sn.  相似文献   

5.
Increased interest in the fractionation of Sn isotopes has led to the development of several techniques for preparing cassiterite (SnO2, the primary ore of Sn) for isotopic analysis. Two distinct methods have been applied in recent isotopic studies of cassiterite: (a) reduction to tin metal with potassium cyanide (KCN) at high temperature (800 °C), with subsequent dissolution in HCl, and (b) reduction to a Sn solution with hydriodic acid (HI) at low temperature (100 °C). This study compares the effectiveness and accuracy of these two methods and contributes additional methodological details. The KCN method consistently yielded more Sn (> 70% in comparison with < 5%), does not appear to fractionate Sn isotopes at high temperatures over a 2‐hour period and produced consistent Sn isotope values at flux mass ratios of ≥ 4:1 (flux to mineral) with a minimum reduction time of 40 min. By means of a distillation experiment, it was demonstrated that HI could volatilise Sn, explaining the consistently low yields by this method. Furthermore, the distillation generated Sn vapour, which is up to 0.38‰ per mass unit different from the starting material, the largest induced Sn fractionation reported to date. Accordingly, the HI method is not recommended for cassiterite preparation for Sn isotopic analysis.  相似文献   

6.
Differentiation analysis using Köhler-Raaz indices has been applied to 284 granitic rocks from various parts of the Tasman Geosyncline in Queensland, New South Wales, Victoria and Tasmania. It was found that the majority (about 80%) of rocks known to be associated with tin mineralization (mostly leucocratic granites and adamellites) have a well defined range of Köhler-Raaz indices (qz=60–70%, F=20–25%, fm=5–15%) in agreement with findings in other parts of the world. Rocks associated with cassiterite deposits usually have a higher tin content than those not carrying cassiterite — but this information has to be used with caution because the form of tin in the rock (i. e. as an economic mineral e. g. cassiterite or in a host mineral, e. g. in biotite) is determined by several factors. All these factors (geochemical, physicochemical and geological) must be considered in an integrated approach to exploration for new tin deposits.  相似文献   

7.
本文对云南省云龙锡矿六种不同颜色的12个锡石样品进行了阴极射线发光、紫外和可见吸收光谱的研究和电子探针分析,证明不同颜色锡石的发光光谱和吸收光谱没有本质上的差别。锡石颜色的变化一方面与杂质元素Fe、W、Nb、Ti的含量有关,主要的还是锡石本身色带结构所决定;锡石颜色深浅变化还与其形成温度和时间有关。  相似文献   

8.
湖南香花岭矽卡岩型锡矿床是南岭地区一个重要的锡多金属矿床,发育有丰富的含锡矿物。在野外和显微镜下观察 基础上,文章利用电子探针技术系统分析了香花岭矽卡岩中含锡矿物的矿物学特征,探讨了锡的成矿过程、成矿流体以及 锡的来源。研究结果表明,香花岭矽卡岩中含锡矿物由锡矿物(锡石、尼日利亚石、孟宪民石等)和富锡矿物(韭闪石、 尖晶石、葡萄石、塔菲石等)组成。锡的成矿有三个阶段:矽卡岩早阶段,Sn进入尖晶石、韭闪石等造岩矿物中,形成富 锡矿物;氧化物阶段,锡矿物如锡石、尼日利亚石、孟宪民石等逐渐晶出;晚期热液阶段,早期含锡矿物热液蚀变原位析 出锡石,或富Sn热液交代早期矿物形成了富锡环边。矽卡岩中成矿流体富含F,CO2,Li等挥发组分,控制了Sn的富集、迁 移、结晶等过程。香花岭矽卡岩中Sn根本上来源于地层,锡的成矿过程反映了Sn在地壳中的地球化学循环过程。  相似文献   

9.
The results obtained with LA-ICP-MS by less abundant lighter 113In isotope and EPMA show that in cassiterite of cassiterite–quartz veins the indium contents do not exceed 160 ppm, while cassiterite from Sn–sulfide veins is characterized by higher indium contents from 40 to 485 ppm; sulfides of Sn–sulfide veins unlike sulfides of cassiterite–quartz veins also have the highest indium contents: Fe-sphalerite (100–25,000 ppm), chalcopyrite (up to 1000 ppm), and stannite (up to 60,000 ppm). Indium contents in the Sn–sulfide ore of the Tigrinoe and Pravourmiiskoe deposits obtained using SR-XRF, ICP-MS and atomic absorption methods range from 10 to 433 ppm with average values of 56–65 ppm. Indium-rich Sn–sulfide mineralization in five large Sn–Ag ore districts of the Far East Russia (Khingansky, Badzhalsky, Komsomolsky, Arminsky, Kavalerovsky) provides the impetus for further exploration of deposits with Sn–sulfide mineralization as the most promising indium resources in Russia. Empirical observations from geology and geochronology of cassiterite–quartz and Sn–sulfide mineralization show that the combined contribution from granite and alkaline–subalkaline mafic sources and multistage ore-forming processes doubled indium resources of deposits being the main factors in the formation of high grade indium mineralization.  相似文献   

10.
Experiments indicate that the solubility of cassiterite can be enhanced by increasing either acidity or alkalinity in hydrothermal solutions as a consequence of the duality of tin.The minimum solubility of cassiterite is found in neutral solutions.F-and CL-coordination compounds of Sn can alternate with hydroxyl coordination compounds with changing pH in the solutions.In this case,F^- and Cl^- and OH^- can be substituted with each other.The dissolution reaction of cassiterite is of reducing nature.High temperature and acidic reducing environment are favorable for the dissolution of cassiterite and the trans-port of Sn^2 compounds in fluids or solutions.High-temperature fluoride and chloride fluids can all dissolve,extract and enrich Sn to form F^- and /or Cl-coordination compounds,However,Fplays a more important role than Cl.F-coordination compounds are more stable and efficient than Cl-coordination compounds during the transport an enrichment of Sn in melts or solutions.The solubili-ty of cassiterite and the amount of Sn extracted from granitic melt depend not only on T,P,pH and Eh in the fluids or solutions,but also on the amounts of dissociated F^- and Cl^- in the fluids.  相似文献   

11.
The Sn-rich Qiguling topaz rhyolite dike intrudes the Qitianling biotite granite of the Nanling Range in southern China; the granite hosts the large Furong Sn deposit. The rhyolite dike is typically peraluminous, volatile-enriched, and highly evolved. Whole-rock F and Sn concentrations attain 1.9 wt.% and 2700 ppm, respectively. The rhyolite consists of a fine-grained matrix formed by quartz, feldspar, mica and topaz, enclosing phenocrysts of quartz, feldspar and mica; it is locally crosscut by quartz veinlets. Lithium-bearing micas in both phenocrysts and the groundmass can be classified as primary zinnwaldite, “Mus-Ann” (intermediate member between annite and muscovite), and secondary Fe-rich muscovite. Topaz is present in the groundmass only; common fluorite occurs in the groundmass and also in a specific cassiterite, rutile and fluorite (Sn–Ti–F) assemblage. Cassiterite and rutile are the only Sn and Ti minerals; both cassiterite and Nb-rich rutile are commonly included in the phenocrysts. The Sn–Ti–F assemblage is pervasive, and contains spongy cassiterite in some cases; cassiterite also occurs in quartz veinlets which cut the groundmass. Electron microprobe and LA-ICP-MS compositions were used to study the magmatic and hydrothermal processes and the role of F in Sn mineralization. The presence of zinnwaldite and “Mus-Ann”, which are respectively representative of early and late mica crystallization during magma differentiation, also suggests a significant decrease in f(HF)/f(H2O) of the system. Cassiterite included in the zinnwaldite phenocrysts is suggested to have crystallized from the primary magma at high temperature. Within the Sn–Ti–F aggregates, rutile crystallized as the earliest mineral, followed by fluorite and cassiterite. Spongy cassiterite containing inclusions of the groundmass minerals indicate a low viscosity of the late fluid. The cassiterite in the quartz veinlets crystallized from low-temperature hydrothermal fluids, which possibly mixed with meteoric water. In general, cassiterite precipitated during both magmatic and hydrothermal stages, and over a range of temperatures. The original fluorine and tin enrichments, f(HF)/f(H2O) change in the residual magma, formation of Ca,Sn,F-rich immiscible fluid, decrease of the f(HF) during groundmass crystallization, and mixing of magma-derived fluids with low-saline meteoric water during the late hydrothermal stage, are all factors independently or together responsible for the Sn mineralization in the Qiguling rhyolite.  相似文献   

12.
西天山(南段)地区地处伊犁亚板块南缘活动带和塔里木板块边缘活动带内.向北突出呈弧形展布的近东西向主干断裂控制本区地层、岩浆岩及地球化学异常的分布.主体为志留、泥盆系富含碳质的碎屑岩-碳酸盐岩沉积.西天山(南段)主要成矿元素及其伴生元素集中在志留系、泥盆系和石炭系中,因而它们是研究区内最有潜力的找矿层位.志留系Au、As、Sb、Sn、Zn、Cr、Ni、Co、Ti富集,微量元素分布不均匀,元素组合多样,局部地段有富集成矿的趋势,地球化学图上有明显的Au、As、Sb、Hg、Cu的单元素异常或多元素的组合异常出现;泥盆系总体地球化学背景偏高,空间分布不均匀,元素组合复杂.富集元素有Au、As、Sb、Hg,有多元素的综合异常显示.根据区内元素异常分布、组合类型及控制异常分布的主要地质因素,将本区划分为4条综合异常带(9条亚带).  相似文献   

13.
南岭成矿带是全球最重要的钨锡成矿带之一,区内钨锡成矿条件优渥,是开展钨锡找矿勘查的重要目标区。然而如何开展钨锡找矿工作,尤其是在已有矿床周缘圈定成矿远景区,是钨锡成矿作用研究以及找矿勘查工作关注的重要科学问题。双园冲矿床位于南岭成矿带中西段,处于荷花坪与柿竹园两个大型锡钨多金属矿田中间,并与两个矿田处于同一构造体系,但目前对该矿床的研究程度较低,由此也制约了其矿床成因研究及该区的找矿部署。本次研究获得双园冲云英岩化花岗岩的锆石和独居石原位LA-ICP-MS U-Pb年龄分别为161.2±2.5Ma和157.1±1.8Ma,与云英岩型矿石中锡石原位LA-ICP-MS U-Pb年龄(158.9±2.9Ma)一致,二者均形成于晚侏罗世,表明其具有密切的成因关系,这一年龄也与南岭成矿带钨锡成矿大爆发时代(150-160Ma)一致。综合对比双园冲锡矿及与其空间相邻的柿竹园和荷花坪锡多金属矿田特征显示,三者成岩成矿时代一致,岩体侵位和矿体分布均受NE向断裂控制,矿体也均赋存于中-上泥盆统碳酸盐岩地层中,并且成矿花岗岩具有相似的岩石学特征和岩浆源区。综合以上信息,本文提出三个矿床可能形成于同一次岩浆热液活动,成矿岩体可能来自地壳深部同一个大岩浆房,柿竹园和荷花坪之间的区域具有发育晚侏罗世花岗岩体及相关钨锡矿的较大潜力。根据双园冲锡矿及其周缘大型锡钨矿床浅部脉状Pb-Zn-Fe-Mn矿化和深部矽卡岩-云英岩型Sn-W矿化的特征,提出研究区乃至整个南岭地区浅部脉状Pb-Zn-Fe-Mn矿化是深部Sn-W找矿勘查的有利部位。  相似文献   

14.
he Sn-(Nb, Ta) mineralization of the Wamba field (central Nigeria) occurs in muscovite-quartz-microcline pegmatites, which are related to the late-orogenic Pan-African (f 550 Ma) "Older Granites". The emplacement of granites and pegmatites was controlled by late Pan-African shear tectonics. The granitoid magmatism was multiphase and has produced peraluminous biotite granite, biotite-muscovite granite, and muscovite granite plutons. Sodic metasomatism has altered highly evolved granite cupolas and many of the pegmatite dikes. The pegmatitic mineralization of predominantly cassiterite is closely associated with albitization. Chemical data of granites and granitic and pegmatitic muscovites show that Rb, Cs, Sn, Nb, and Ta are enriched during both magmatic and postmagmatic evolution, with highest contents of these elements in early muscovites of the albitized and mineralized pegmatites. Trace-element chemistry of the pegmatitic muscovites reveals a chemical zonation of the pegmatite field related to the late-orogenic shear system.  相似文献   

15.
The Dachang mining district is the second largest producer of Sn in China and an important source of other metals. The known mineralizations can be divided into four groups: (1) cassiterite + Cu-Fe-Pb-Zn sulfides and sulfosalts, (2) Zn-Cu skarn, (3) Sb-W veins and (4) residual and placer concentrations of Sn and Fe oxides. Most orebodies are hosted by Upper Devonian calcareous, marly and quartzitic formations in spatial association with Cretaceous Yanshanian magmatites. A characteristic feature is the occurrence of stratiform, lens-shaped orebodies which appear to represent the root zone of overlying stockwork mineralizations. The metallogeny of the district may be interpreted in terms of an Upper Devonian Sn and polymetallic concentration with subsequent remobilization and, possibly, the introduction of additional elements during the late stages of the Yanshanian magmatism.  相似文献   

16.
阎公盛 《矿床地质》1987,6(1):45-55
铁嶂锡矿床赋矿围岩为下侏罗统金鸡组下部的砂页岩,其锡含量较高,为矿源层。矿体分布于北东向和北西向断裂构造中,可分为大脉型与细脉带型矿体。锡石有两类:一类为沉积的胶状锡石和由胶体变晶生成的微晶锡石,分布于富动植物化石和碳质的千枚状页岩和富锡的砂岩结核中;第二类为粒状锡石,与石英、硫化物一起呈脉状产出。矿床系沉积变质热液改造成因。  相似文献   

17.
The East Kemptville Sn deposit in southwestern Nova Scotia was discovered in 1978 by Shell Canada Resources, Limited using regional till exploration procedures. In 1977 and 1978, southern Nova Scotia was covered by a government-funded regional centre-lake bottom sediment survey (1 site per 5 km2) for Cu-Pb-Zn-Ag-Ni-Co-Fe-Mn-Ca-Mg-Mo-Hg-As-U-LOI. Detailed lithogeochemical studies on drill core from East Kemptville have demonstrated significant roles for the elements Zn-Cu-Th-Li-F-Sn-Cl-Rb in the hydrothermal mineralization event. Most of these significant mineralizing elements were not analyzed as part of the original lake sediment survey.Later, in 1985, a subset of 55 lake sediment samples from the deposit area was analyzed for Sn, Rb, F and Cl. The pilot study was aimed to test the applicability of these lithophile elements to regional centre-lake bottom sediment geochemical programs. Anomalous values of F, Rb and Sn form a distinct halo of elevated levels southwest, southeast and northeast of the East Kemptville deposit, which appears to lie in an area of background values. The detailed till sampling undertaken by Shell Canada at East Kemptville provides a check, especially for Sn as to probable sources for these elements found in the centre-lake bottom sediments.Cassiterite is the main economic mineral at East Kemptville. Trace wolframite is found along with subsidiary chalcopyrite and sphalerite. Zn and Cu are recovered as by-products at the mine. Heavy minerals were separated from a bulk lake sediment sample from Moosefly Lake (the site of the highest Sn value from the regional survey subset). Spot analysis by scanning electron microscope indicates the presence of angular and discrete grains of cassiterite in the centre-lake bottom sediment, in addition to numerous grains of zircon, monazite and magnetite.The Sn anomaly in the centre-lake bottom sediment is due, at least in part, to the presence of discrete cassiterite grains. Their lack of abrasion would seem to indicate derivation from the nearby known cassiterite-rich tills. The lack of correlation of Sn data with organic material (as LOI) and the other elements probably indicates the dominance of mechanical over chemical dispersion processes in Sn distribution from the tills to the lakes.A common dispersion model for centre-bottom lake sediment surveys is one of initial glacial clastic dispersion, followed by subsequent hydromorphic dispersion into the lake basins. Although the dominance of hydromorphic processes is recognized, it is clear that clastic dispersion models must also be considered. Centre-lake bottom surveys appear to have greater application than previously presumed in the search for lithophile elements commonly dispersed as refractory grains.  相似文献   

18.
Sn–W deposit of the Mueilha mine is one of many other Sn–W deposits in the Eastern desert of Egypt that associated with albite granite. Two forms of Sn–W mineralizations are known at the Mueilha Sn-mine area, namely fissure filling quartz veins and greisen. Cassiterite and/or wolframite, sheelite, and beryl are the main ore minerals in the greisen and quartz veins. Subordinate chalcopyrite and supergene malachite and limonite are also observed in the mineralized veins. To constrain the P–T conditions of the Sn–W mineralizations, fluid inclusions trapped in quartz and cassiterite, have been investigated. The following primary fluid inclusion types are observed: CO2-rich, two-phase (L?+?V) aqueous, and immiscible three-phase (H2O–CO2) inclusions. Low temperature and low salinity secondary inclusions were also detected in the studied samples. Microthermometric results revealed that Sn–W deposition seem to have taken place due to immiscibility at temperature between 260°C and 340°C, and estimated pressure between 1.2 to 2.2 kb. Microthermometric results of fluid inclusions in fluorite from fluorite veins illustrated that fluorite seems to be deposited due to mixing of two fluids at minimum temperature 140°C and 180°C, and estimated minimum pressure at 800 bars.  相似文献   

19.
Oxygen isotope equilibrium fractionation constants (β18O-factors) of cassiterite were evaluated on the basis of heat capacity and X-ray resonant (Mössbauer spectroscopy and X-ray inelastic scattering) data.The low-temperature heat capacity of cassiterite was measured in the range from 13 to 340 K using an adiabatic calorimeter. Results of measurements of two samples agree very closely but deviate more than 5% from previous heat capacity data used for calculation of thermodynamic functions. The temperature dependence of heat capacity was treated using the modern version of the Thirring expansion, and the appropriate temperature dependence of the vibrational kinetic energy was found.Measurements of temperature-dependent Mössbauer parameters of cassiterite were conducted in the range from 300 to 900 K. The attempt to describe Mössbauer fraction and the second order Doppler (SOD) shift on the basis of the Debye model failed. The first term of the Thirring expansion of the Mössbauer SOD shift agrees with that calculated from the Sn sublattice vibration density of states (VDOS) obtained via synchrotron X-ray scattering. Based on this agreement we calculated the kinetic energy of the cassiterite Sn sublattice from VDOS.From the kinetic energy of the total cassiterite crystalline lattice and its Sn sublattice, β18O-factors of cassiterite were computed in the temperature range 300-1500 K by the method of Polyakov and Mineev (2000). Appropriate polynomials, which are valid at temperatures above 400 K, are the following:
  相似文献   

20.
金坑Sn-Cu矿床是粤东地区新发现的典型Sn-Cu共生矿床.矿区发育花岗闪长斑岩、中粗粒黑云母花岗岩和细粒花岗岩等多种侵入岩以及高基坪组火山岩,而这些岩石的年代学格架,及其与成矿过程关系还不清楚.因此,本文以粤东地区新发现的金坑铜锡矿床为研究对象,系统开展不同岩性侵入岩锆石和矿石锡石的U-Pb年龄测定,旨在浅析Sn-C...  相似文献   

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