内蒙古东山湾钨钼多金属矿床成矿流体地球化学特征及成因

东山湾钨钼多金属矿床为大兴安岭南段新发现的一斑岩型矿床,产于燕山晚期花岗斑岩体与二叠系的接触带附近。该矿床主要发育细脉、微细脉浸染型矿化,其钨钼银多金属热液成矿作用划分为黑钨矿-锡石-毒砂-石英阶段(Ⅰ)、毒砂-辉钼矿-石英阶段(Ⅱ)、银多金属硫化物-石英阶段(Ⅲ) 3个阶段。为了系统研究该矿床不同成矿阶段成矿流体的来源、性质及其演化特点,对不同成矿阶段样品进行了流体包裹体岩相学、显微测温学及碳、氢、氧同位素研究。结果表明:Ⅰ、Ⅱ阶段石英中流体包裹体的均一温度分别为232.7~321.7 ℃和201.2~352.7 ℃,盐度(w(NaCl))分别为3.4%~9.8%和4.1%~10.4%,成矿流体属中温、中等盐度不均匀的NaCl-H₂O体系型热液;Ⅲ阶段石英中流体包裹体的均一温度变化范围为198.6~273.5 ℃,盐度为5.0%~8.4%,成矿流体属中低温、中低盐度均匀的NaCl-H₂O体系型热液;Ⅱ阶段石英样品的δ¹⁸O值为7.5‰~9.0‰,石英中流体包裹体的δD_H2O-SMOW值与δ¹³C_PDB值分别为-175.6‰~-160.3‰与-23.5‰~-20.1‰。成矿流体具有岩浆分异热液的特点,并伴随大气降水的大量加入,流体运移过程中地层有机质的加入导致了成矿流体具有较低的δD_H2O-SMOW值、δ¹³C_PDB值;成矿流体的不混容作用、大气降水的加入是导致区内钨钼沉淀、成矿的主要机制,而银多金属矿化则可能由成矿流体的降温冷却所引起。     

钨的迁移形式成矿机理新探

通过对钨羰基络合物及钨合金氢化物的物理化学性质、钨矿床矿物流体包裹体的化学组成、钨矿物的化学成分、主要共生伴生矿物组合的研讨,结合钨成矿的地质背景和环境,认为钨羰基络合物及钨合金氢化物是钨的主要迁移形式。它们形成于地球深部高压、富氢、富CO的强还原环境,随着岩浆、热液、热气迁移至地壳浅部,由于压力、温度下降,氧逸度大增,H2、CO逃逸、氧化,钨羰基络合物、钨合金氢化物分解,氧化形成钨矿物,沉淀富集形成钨矿床。     

东昆仑西段黑山-祁漫塔格成矿带钨锡成矿地质条件及找矿方向

从沉积建造、岩浆侵入、构造活动等方面探讨了新疆东昆仑西段黑山-祁漫塔格成矿带钨锡元素的成矿地质条件,利用1：10万水系沉积物测量成果,结合成矿地质条件,初步划分了钨锡的找矿靶区,为钨锡矿产的寻找指出了方向.     

Upper Ordovician graptolites from the Wagonga Beds near Batemans Bay,New South Wales

Two graptolite faunas are described from outcrops of the Wagonga Beds near Batemans Bay on the south coast of N.S.W. They are of late Eastonian and early Bolindian age. The faunas have been found in two geographically separate localities and, in spite of structural complexities, it is now suggested that the greater part of the Wagonga Beds was deposited in the Late Ordovician. The chert and volcanicrich Wagonga Beds were accumulated prior to, or as contemporaneous lateral facies equivalents of, the thick undifferentiated Upper Ordovician ‘slates and grey‐wackes unit’ that crops out in the same general region.     

Sm‐Nd and Rb‐Sr dating of Archaean gneisses,eastern Yilgarn Block,Western Australia

Sm‐Nd and Rb‐Sr isotopic data for Archaean gneisses from three localities within the eastern Yilgarn Block of Western Australia indicate that the gneisses define a precise Rb‐Sr whole rock isochron age of 2780 ± 60 Ma and an initial ⁸⁷Sr/⁸⁶Sr of 0.7007 ± 5. The Sm‐Nd isotopic data do not correspond to a single linear array, but form two coherent groups that are consistent with a c. 2800 Ma age of crust formation, with variable initial Nd. These results indicate that the gneiss protoliths existed as continental crust for a maximum period of only c. 100 Ma, and probably for a much shorter time, prior to the formation of the 2790 ±30 Ma greenstones.     

地面高精度磁测在印尼滨海型磁铁矿应用

综合运用低纬度化极与建立模型正演等数据处理手段进行隐伏矿体预测,发现与成矿有关的磁异常,显示良好成矿前景。钻孔证实有工业矿体。     

桂北苗儿山-越城岭印支期(含电气石)白云母花岗岩及相关的Nb-Ta-W成矿作用

桂北苗儿山-越城岭岩基是一个多时代复式岩体,出露有新元古代、加里东期、印支期和燕山期花岗岩,与花岗岩相关有多个加里东期和印支期的大型W矿床,如牛塘界钨(锡)、界牌钨铜、云头界钨钼矿床等,另外越城岭的戈洞坪地区还发现了燕山期铌钽成矿作用。豆乍山岩体位于苗儿山岩体中部,主要由二云母花岗岩组成,本次研究在豆乍山钻孔样品中发现富含Nb-Ta-W氧化物的(含电气石)白云母花岗岩,为进一步全面认识苗儿山-越城岭地区的多时代成矿信息,查明不同类型成矿过程,对钻孔内花岗岩及其成矿作用开展了详细的研究。钻孔样品主要包含二云母花岗岩和细粒的(含电气石)白云母花岗岩,其中细粒的(含电气石)白云母花岗岩穿插了主岩体。详细的矿物学工作显示(含电气石)白云母花岗岩中含有多样的稀有金属副矿物,其中白云母花岗岩中有铌铁矿族矿物、铌铁金红石、锡石等氧化物,而含电气石白云母花岗岩则包含了复杂的Nb-Ta-W的氧化物矿物集合体,主要为铌铁矿族矿物、钨铌铁矿、骑田岭矿和黑钨矿等;另外还在白云母花岗岩中发现一些富含白钨矿的电气石细脉。白云母花岗岩中岩浆锡石U-Pb定年结果为219±4 Ma,属于印支期成矿作用。结合岩相学观察结...     

Geochronologic and isotope geochemical constraints on magmatism and associated W–Mo mineralization of the Jitoushan W–Mo deposit,middle–lower Yangtze Valley

The Jitoushan W–Mo ore body is a typical skarn-type deposit with the potential for porphyry Mo mineralization at depth. As it is newly discovered, only a few studies have been conducted on the geochronology and ore genesis of this deposit. The ore district consists of Cambrian to Silurian sedimentary and low-grade metasedimentary strata, intruded by granodiorite, diorite porphyry, granite porphyry, and quartz porphyry. Skarn W–Mo ore bodies are hosted in the contact zone between the granodiorite and Cambrian limestone strata. Within the granodiorite near the contact zone, quartz vein type and disseminated sulphide mineralization are well developed. The Mo-bearing granite porphyry has been traced at depth by drilling. Our results reveal two discrete magmatic events at ca. 138 and ca. 127 Ma in the study area. The molybdenite Re–Os isochronal age of 136.6 ± 1.5 million years is consistent with the first magmatic event. The zircon Hf isotope (?_Hf(t) =??12.55?3.91), sulphide isotopes (δ³⁴S = 3.32–5.59‰), and Re content of molybdenite (Re_content = 6.424–19.07 μg) indicate that the ore-forming materials were mainly derived from the deep crust. The regional tectonic system switched from a Late Jurassic transpressive regime to an earliest Cretaceous extensional regime at ca. 145 Ma, and at ca. 138 Ma, the Jitoushan W–Mo deposit formed in an extensional setting.     

Photometric study of the newly discovered short period eclipsing binary 1SWASP J133105.91 + 121538.0

A total of 311 BVRI observations were carried out on 4 May 2013 for the new short period W UMa system 1SWASP J133105.91 + 121538.0 using the 1.88 m reflector telescope of Kottamia Astronomical Observatory (KAO) at NRIAG. A photometric solution of these light curves was obtained by means of Wilson–Devinney (WD) code. A spotted model was applied to treat the asymmetry of the light curve. The results show that the more massive component is hotter than the less massive one with about ΔT ∼ 300 K. The system is at a distance of 89 ± 3.6 pc. Based on the physical parameters of the system, we investigate the evolutionary state of the components. Both components are above the zero age main sequence (ZAMS) track by about 0.2 magnitudes.     

A Review of: “Geographic Information Systems for Geoscientists—Modelling with GIS”

Distances from points to closest shorelines in a given direction are used, for example, in some models for estimating wave exposure. Such distances, also called fetch lengths, can be determined using standard geographic information systems. However, performance may be a problem if these distances are required for a great number of study points. Two new algorithms for determining fetch lengths for study points in the same directions are presented in this paper. It is assumed that the two‐dimensional map is stored in vector format, i.e. shorelines of islands and mainland are stored as polygons. The first algorithm works on a set of undirected line segments derived from the shoreline polygons. The other works on a raster representation of the map. The algorithm saves memory by postponing the rasterisation until necessary. Both of the new algorithms have superior efficiency to a previously reported algorithm when the number of study points is large.