The Batu Hijau porphyry copper-gold deposit, Sumbawa Island, Indonesia   总被引：4，自引：0，他引：4  

Simon J. Meldrum  Romeo S. Aquino  Rene I. Gonzales  Robert J. Burke  Artha Suyadi  Bambang Irianto  Donald S. Clarke 《Journal of Geochemical Exploration》1994,50(1-3)

The Batu Hijau porphyry Cu---Au deposit lies in southwest Sumbawa Island, Indonesia. It is a world-class porphyry Cu deposit in an island are setting, and is typical of this deposit type in most features, including igneous association, morphology, hydrothermal alteration and mineralisation style.The region was not previously recognised as a porphyry Cu province; disseminated Cu sulphides were first recognised in float samples in southwest Sumbawa in 1987. Associated stream sediment sampling identified a broad area of anomalous Au and Cu in an area of greater than 5 km² around Batu Hijau, including 169 ppb Au in BLEG samples and 580 ppm Cu in stream silts 1 km from the deposit. Mineralisation in bedrock at surface contains > 0.1 wt % Cu and > 0.1 ppm Au over an area of 0.6 km × 1.2 km, including a zone 300 m × 900 m containing > 0.3 wt % Cu. Areas with elevated Mo (> 30 ppm) form a distinctive annulus around this Cu-rich zone.Batu Hijau mineralisation is hosted in a tonalite intrusive complex, and diorite and metavolcanic wallrocks. There are no post-mineralisation igneous intrusions or breccia pipes within the deposit. The main tonalite intrusion forms a stock in the centre of the deposit, where it generally displays intensely pervasive potassic (biotite with magnetite-quartz) alteration and hosts most of the higher grade mineralisation. Younger tonalite dykes intruding the centre of this stock are generally less altered and mineralised than the older tonalite.The core zone of potassic alteration grades outward into extensive propylitic alteration (chlorite-epidote), with both variably overprinted by widespread fracture controlled intermediate argillic alteration (sericite-chlorite), and minor phyllic (sericite-pyrite) and sodic (albite) alteration. Argillic (sericite-kaolinite) and advanced argillic (kaolinite-alunite-pyrophyllite) assemblages occur near surface.Copper and Au grades within the orebody show a positive correlation with quartz stockwork intensity, although disseminated Cu sulphides are also common. Chalcopyrite and bornite are the principle hypogenal minerals, with minor chalcocite. Oxidation extends to a depth of 5 m to 85 m below surface across the deposit, and is underlain by weak supergene mineralisation. Drill testing of the deposit down to 650 m below surface reveals a single cylindrical to conical orebody of 334 million tonnes grading 0.8 wt % Cu and 0.69 gm per tonne Au; the depth extent of mineralisation is unknown.  相似文献   

GCM-derived climatic change scenarios due to a CO2-doubling applied for the Mediterranean area     

Dr. H. J. Jung  Prof. W. Bach 《Theoretical and Applied Climatology》1985,35(4):323-339

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Relationships between marginal thrusting and movement on major,internal shear zones in the Northern Highland Caledonides,Scotland     

Simon P Kelley  Derek Powell 《Journal of Structural Geology》1985,7(2):161-174

The development of the syn-metamorphic Sgurr Beag slide zone, a major ductile shear zone of initially low dip, caused at least 50 km north-western thrust displacement of part of the internal metamorphic complex of the Northern Highland Caledonides of Scotland. Initiation of the zone, and movements upon it, were earlier than formation of the marginal Moine Thrust zone. Movement on the zone followed but overlapped the peak Caledonian metamorphism and the mid to high amphibolite facies mineral assemblages, fabrics and structures produced during the development of the slide zone and those surviving from earlier events, were reworked under greenschist facies conditions during mylonitization associated with initiation of the Moine Thrust zone. Displacements on the slide zone and thrust movements were separated by emplacement of a regional suite of pegmatites and a considerable change of metamorphic grade. Thus, they may not constitute members of a progressive sequence of Caledonian thrusts formed over a short time interval. Rather, preliminary isotopic data may imply an interval of c. 25 Ma between movement on the slide zone and final, ductile translation along the Moine Thrust zone.  相似文献   

Equatorial Indian Ocean evaporation estimates from operational meteorological satellites and some inferences in the context of monsoon onset and activity     

Baby Simon  Pranav S. Desai 《Boundary-Layer Meteorology》1986,37(1-2):37-52

The estimation of evaporation from the sea surface is not yet achieved adequately by remote sensing techniques, in general. However, for approximate averaged estimates over moderate space and time scales over a specific tropical region, e.g., weekly values over the Indian Ocean as needed in monsoon moisture diagnosis, it may be possible to extrapolate satellite wind and humidity data to the ocean surface and then use bulk aerodynamic parameterization for estimating evaporation. In the present investigation, GOES low-level cloud winds and TIROS-N moisture profiles over the Indian Ocean are extrapolated to the ocean surface. The planetary boundary layer (PBL) wind shear is obtained over different sub-regions and periods during the monsoon season, by reference to objectively analysed fields. These shear values are applied to GOES satellite winds to obtain sea-surface winds. The humidity extrapolation was based on (i) an exponential fit for water vapour density and (ii) a vertical distribution of relative humidity approximately proportional to atmospheric pressure. The exchange coefficient is varied slightly depending on wind speed and boundary-layer stability inferred approximately from TIROS-N sea surface temperatures and temperature profiles. The evaporation estimate as based on these satellite parameters is assessed by comparison with ships' surface observations. Sensible heat exchange is also estimated and assessed. Some inferences based on these estimates are also presented, in relation to monsoon onset and activity.  相似文献   

Biological marker compounds as indicators of the depositions! history of the Maoming oil shale     

Simon C. Brassell  Geoffrey Eglinton  Fu Jia Mo 《Organic Geochemistry》1986,10(4-6)

The Eocene Maoming oil shale from Guangdong Province occurs as a laterally uniform stratigraphic section, typically 20–25 m thick, from which the aliphatic hydrocarbon constituents of six representative samples were investigated using GC and C-GC-MS. The sediments evaluated included the basal lignite, a vitrinite lens from the overlying claystone, and four intervals from the massive oil shale bed. As expected, the lignite and vitrinite differ markedly from the oil shales. The lignite is dominated by bacterial hopanoids and components of higher plant origin, including C₂₉ steroids and triterpenoids such as oleanenes. Visually, the oil shale samples show corroded and degraded phytoclasts, spores, wispy particles of fluorescent organic material attributable to dinoflagellates and, especially in the uppermost sample, colonial algal bodies. The distributions of biological markers in the oil shales show many features in common, notably a dominance of dinoflagellate-derived 4-methylsteroids, and a significant proportion of higher-plant derived n-alkanes with marked odd-over-even carbon number predominance. Overall, they exhibit several features that resemble characteristics of the Messel shale. The hydrocarbons of the lowest shale horizon suggest that there may have been a gradual transition between deposition of the original peat and the subsequent oil shales. The aliphatic hydrocarbons of the uppermost shale are dominated by a number of C₃₁ and C₃₃ botryococcane homologues and other unusual branched alkanes possibly derived from green algae. All of the samples are immature. Overall, molecular and microscopic examination of the stratigraphic succession of the Maoming oil shale suggests a shallow, lacustrine environment within which peats were deposited. This lake subsequently deepened to support abundant algal populations, especially dinoflagellates, culminating in a dominance of botryococcoid algae.  相似文献   

Geochemical studies in the drainage basin of the Rio Vouga,Portugal. IV. Impact of land use on the hydrogeochemistry of natural waters in the Vouzela region   总被引：1，自引：0，他引：1  

Rob N. J. Comans  Cornelis H. Van Der Weijden  Simon P. Vriend 《Environmental Geology》1987,9(2):119-128

A hydrogeochemical study of the impact of land use on the composition of natural waters in the Vouzela region in northern Portugal was carried out during the summer of 1983. Water samples were collected from spring and major streams in the area and analyzed for major constituents and some trace elements. Analysis of variance and subsequent pairwise contrast tests demonstrated that waters from agricultural areas are significantly enriched in constiluents such as Na, K, Ca, Mg, Sr, Cl, SO₄, and NO₃. High concentrations of these ions in agricultural areas are the result of both the application of fertilizers and enhanced evaporation by the intensive irrigation of agricultural lands. Constitutents such as H₄SiO₄, HCO₃, F, and probably Li, which are typically related to mineral weathering, were not affected by land use. In waters from forested areas the concentration of most constituents was about 20% higher than in waters from uncultivated areas with mainly a grass cover. This reflects the difference in the evapotranspiration of these two vegetation types. The chemistry of the Rio Zela clearly reflects differences in land use in the Rio Zela valley.  相似文献   

Thermodynamics of plagioclase II: Temperature evolution of the spontaneous strain at the I\bar 1 \leftrightarrow P\bar 1 phase transition in anorthite     

Simon A. T. Redfern  Ekhard Salje 《Physics and Chemistry of Minerals》1987,14(2):189-195

The temperature dependence of the lattice parameters of pure anorthite with high Al/Si order reveals the predicted tricritical behaviour of the \(I\bar 1 \leftrightarrow P\bar 1\) phase transition at T _c ^* =510 K. The spontaneous strain couples to the order parameter Q° as x _i∝S _xQ ⁱ Q°² with S _xQ ¹ =4.166×10^?3, S _xQ ² =0.771×10^?3, S _xQ ³ =?7.223×10^?3 for the diagonal elements. The temperature dependence of Q° is $$Q^{\text{o}} = \left( {1 - \frac{T}{{510}}} \right)^\beta ,{\text{ }}\beta = \tfrac{{\text{1}}}{{\text{4}}}$$ A strong dependence of T _c ^* , S _xQ ⁱ and β is predicted for Al/Si disordered anorthite.  相似文献   

内蒙古苏尼特左旗南两类花岗岩同位素年代学及其构造意义   总被引：93，自引：1，他引：92  

陈斌  赵国春等 《地质论评》2001,47(4):361-367

内蒙古北部索伦缝合带（索伦-苏尼特左旗-锡林浩特）被多数中外学者认为是西伯利亚板块南缘和华北板块北缘的最终缝合带,本文选择该缝合带上苏尼特左旗南两类花岗岩-与俯冲有关和与碰撞有关的岩浆岩（分别叫弧岩浆岩和碰撞岗岩）进行同位素年代学研究,结果表明：（1）弧岩浆活动有两期,分别约为490Ma和310Ma(锆石U-Pb,SHRIMP);碰撞花岗岩的侵位年代在230-250Ma(Rb-Sr全岩和锆石U-Pb);（2）根据本文新的年代学数据,索伦缝合带的最终缝合时间可能是在230-310Ma,这显然不同于国内多数学者坚持的“晚泥盆世碰撞”模式;而Sengor等推测的“晚二又开展碰撞”模式与本文数据一致。  相似文献   

Altered mafic lower continental crust as a source for low δ18O-granodiorites (Damara orogen, Namibia)?     

S. Jung  K. Mezger  S. Hoernes  R. Hoffbauer 《Mineralogy and Petrology》2007,91(1-2):1-10

Summary New oxygen isotope data for metaluminous granites from the basement-dominated part of the Damara orogen (Namibia) range from 9.1 to 11.9‰. These data, together with previously published Sr, Nd and Pb isotope data indicate that these granites and associated peraluminous granites originated from felsic meta-igneous basement sources. New and unusually low oxygen isotope data for metaluminous granodiorites extend now the range of δ¹⁸O values from ca. 12 to 6‰ for this rock type. These low oxygen isotope values approach the values observed in mafic quartz diorites for which a model of derivation from depleted mafic lower crust has been established. In view of the higher Pb isotope ratios but lower oxygen isotope values of the granodiorites relative to the mafic quartz diorites, it is concluded that the granodiorites represent partial melts of an undepleted but strongly altered mafic lower crust. Most of the peraluminous and metaluminous granites and the metaluminous granodiorites have identical U–Pb monazite, allanite and zircon ages of ca. 510–500 Ma implying partial melting of distinct basement rocks of Archaean to Proterozoic age at the peak of regional high-grade metamorphism.  相似文献   

Characterizing flow zones in a fractured and karstified limestone aquifer through integrated interpretation of geophysical and hydraulic data     

Nathalie Van Meir  David Jaeggi  Martin Herfort  Simon Loew  Philippe A. Pezard  Gérard Lods 《Hydrogeology Journal》2007,15(2):225-240

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