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1.
Scheelite-mineralized microtonalite sheets occur on the SE margin of the end-Caledonian Leinster Granite in SE Ireland. Scheelite,
polymetallic sulphides and minor cassiterite occur in veins in the microtonalites, disseminated throughout the greisened microtonalite
sheets and in the adjacent wallrocks. Two major mineralized vein types occur in the microtonalite sheets: (1) Scheelite ± arsenopyrite ± pyrrhotite
occur in quartz-fluorite veins, generally without a muscovite selvage; (2) Sphalerite ± chalcopyrite ± pyrite ± galena ± cassiterite ± stannite
occur in quartz + fluorite veins with a coarse muscovite selvage and are often intergrown with the muscovite. Quartz-hosted
fluid inclusions were examined from representative samples of both vein types using petrographic, microthermometric and laser
Raman spectroscopic techniques. Three distinct types of fluid inclusions have been recognized. Primary, vapour rich Type 1
inclusions in quartz from the scheelite-mineralized veins are of H2O-CO2-CH4-N2 ± H2S ± NaCl composition and formed between 360–530 °C. Primary and secondary, liquid-rich Type 2 fluid inclusions in the base
metal sulphide-mineralized veins are of H2O-CH4-N2 ± H2S-NaCl composition and formed between 340–480 °C. They also occur as pseudosecondary and secondary inclusions in scheelite-mineralized
veins. Late dilute, low temperature H2O-NaCl + KCl fluid inclusions may be related to late-Caledonian convection of meteoric waters around the cooling Leinster
Granite batholith.
Received: 4 September 1996 / Accepted: 23 May 1997 相似文献
2.
3.
Employing clean and quantitative techniques, a marine monitoring programme succeeded in detecting large surface elevations in the concentrations of dissolved Cu, Zn and Pb in the marine surface waters of Puget Sound adjacent to Seattle and Tacoma, Washington. Physical mixing with cleaner waters was the controlling factor in reducing the dissolved concentrations of Cu downstream of these contaminated regions. Comparisons between Puget Sound waters and coastal waters adjacent to Puget Sound suggest that a portion of this Cu, Zn and Pb pollution is being advected out of Puget Sound. The low Ni and Cd concentrations found in this study indicate that these trace metals are not a significant pollution problem in the main basin of Puget Sound. 相似文献
4.
Willard S. Moore Herbert W. Feely Yuan-Hui Li 《Earth and Planetary Science Letters》1980,49(2):329-340
Measurements of the228Ra/226Ra activity ratio in the waters of the Greenland, Norwegian and Labrador Seas and Baffin Bay reveal strong horizontal gradients in the surface waters. The coastal waters are dominated by228Ra injection from nearshore sediments. There is an inverse correlation between the228Ra/226Ra activity ratio and salinity in the 30–36‰ salinity range. Vertical profiles indicate that the228Ra/226Ra activity ratio is also strongly coupled toσθ except for some regions where228Ra is being injected into higher density water as these isopycnals intersect coastal areas. We use these measurements in the area of formation of North Atlantic Deep Water to estimate that this water mass forms with a228Ra/226Ra activity ratio of 0.10. 相似文献
5.
Taro Takahashi Stewart C. Sutherland Rik Wanninkhof Colm Sweeney Richard A. Feely David W. Chipman Burke Hales Gernot Friederich Francisco Chavez Christopher Sabine Andrew Watson Dorothee C.E. Bakker Ute Schuster Nicolas Metzl Hisayuki Yoshikawa-Inoue Masao Ishii Takashi Midorikawa Yukihiro Nojiri Arne Krtzinger Tobias Steinhoff Mario Hoppema Jon Olafsson Thorarinn S. Arnarson Bronte Tilbrook Truls Johannessen Are Olsen Richard Bellerby C.S. Wong Bruno Delille N.R. Bates Hein J.W. de Baar 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(11):2075-2076
6.
Features of coastal upwelling regions that determine net air-sea CO<Subscript>2</Subscript> flux 总被引:1,自引:0,他引:1
Debby Ianson Richard A. Feely Christopher L. Sabine Lauren W. Juranek 《Journal of Oceanography》2009,65(5):677-687
The influence of the coastal ocean on global net annual air-sea CO2 fluxes remains uncertain. However, it is well known that air-sea pCO2 disequilibria can be large (ocean pCO2 ranging from ∼400 μatm above atmospheric saturation to ∼250 μatm below) in eastern boundary currents, and it has been hypothesized
that these regions may be an appreciable net carbon sink. In addition it has been shown that the high productivity in these
regions (responsible for the exceptionally low surface pCO2) can cause nutrients and inorganic carbon to become more concentrated in the lower layer of the water column over the shelf
relative to adjacent open ocean waters of the same density. This paper explores the potential role of the winter season in
determining the net annual CO2 flux in temperate zone eastern boundary currents, using the results from a box model. The model is parameterized and forced
to represent the northernmost part of the upwelling region on the North American Pacific coast. Model results are compared
to the few summer data that exist in that region. The model is also used to determine the effect that upwelling and downwelling
strength have on the net annual CO2 flux. Results show that downwelling may play an important role in limiting the amount of CO2 outgassing that occurs during winter. Finally data from three distinct regions on the Pacific coast are compared to highlight
the importance of upwelling and downwelling strength in determining carbon fluxes in eastern boundary currents and to suggest
that other features, such as shelf width, are likely to be important. 相似文献
7.
V. Gallagher M. Feely H. Högelsberger G. R. T. Jenkin A. E. Fallick 《Mineralium Deposita》1992,27(4):314-325
Mo mineralization within the Galway Granite at Mace Head and Murvey, Connemara, western Ireland, has many features of classic porphyry Mo deposits including a chemically evolved I-type granite host, associated K- and Si-rich alteration, quartz vein(Mace Head) and granite-hosted (Murvey) molybdenite, chalcopyrite, pyrite and magnetite mineralization and a gangue assemblage which includes quartz, muscovite and K-feldspar. Most fluid inclusions in quartz veins homogenize in the range 100–350°C and have a salinity of 1–13 eq. wt.% NaCl. They display Th-salinity covariation consistent with a hypothesis of dilution of magmatic water by influx of meteoric water. CO2-bearing inclusions in an intensely mineralized vein at Mace Head provide an estimated minimum trapping temperature and pressure for the mineralizing fluid of 355°C and 1.2 kb and are interpreted to represent a H2O-CO2 fluid, weakly enriched in Mo, produced in a magma chamber by decompression-activated unmixing from a dense Mo-bearing NaCl-H2O-CO2 fluid. 34S values of most sulphides range from c. 0 at Murvey to 3–4 at Mace Head and are consistent with a magmatic origin. Most quartz vein samples have 18O of 9–10.3 and were precipitated from a hydrothermal fluid with 18O of 4.6–6.7. Some have 18O of 6–7 and reflect introduction of meteoric water along vein margins. Quartz-muscovite oxygen isotope geothermometry combined with fluid inclusion data indicate precipitation of mineralized veins in the temperature range 360–450°C and between 1 and 2 kb. Whole rock granite samples display a clear 18O-D trend towards the composition of Connemara meteoric waters. The mineralization is interpreted as having been produced by highlyfractionated granite magma; meteoric water interaction postdates the main mineralizing event. The differences between the Mace Head and Murvey mineralizations reflect trapping of migrating mineralizing fluid in structural traps at Mace Head and precipitation of mineralization in the granite itself at Murvey. 相似文献
8.
Magma mixing and mingling textures in granitoids: examples from the Galway Granite, Connemara, Ireland 总被引:16,自引:0,他引:16
Summary ?Many granitoid intrusions display textural evidence for the interaction of mafic and silicic magmas during their genesis.
The ∼ 400 Ma Galway Granite exhibits excellent evidence for magma mixing and mingling both at outcrop/map scale (magma mingling
and mixing zones), and at thin-section/crystal scale (mixing textures). These textures – quartz ocelli, rapakivi feldspars,
acicular and mixed apatite morphologies, inclusion zones in feldspars, anorthite ‘spikes’ in plagioclase, sphene ocelli, K-feldspar
megacrysts in mafic microgranular enclaves (MME), and mafic clots – constitute a textural assemblage whose origin can be explained
in terms of magma mixing and mingling models. Furthermore, textures from this assemblage have been recorded throughout the
Galway batholith indicating that magma mingling and mixing played a key role during its evolution.
Received November 18, 2000; revised version accepted November 6, 2001 相似文献
9.
Richard A. Feely 《Marine Chemistry》1975,3(2):121-156
During cruises 71-A-12 and 73-A-3 of the R/V “Alaminos” eighty-six samples of suspended matter at eleven near-bottom stations in the Gulf of Mexico and northwestern Caribbean Sea were collected, and simultaneously, values for light scattering were measured. Selected samples of the suspended matter were analyzed for particulate aluminum, silicon, iron, calcium, magnesium, organic carbon and inorganic carbon. The results indicate that a permanent but highly variable near-bottom nepheloid layer exists in the Gulf of Mexico but not in the northwestern Caribbean Sea. Average total-suspended loads in the Gulf of Mexico nepheloid layer are two times higher than in the clear water above the nepheloid layer.Since there is a significant increase in the alumino-silicate fraction and a corresponding decrease in the organic fraction of the suspended matter in the nepheloid layer relative to the overlying water, it appears that sediments are the most probable source of the increased concentrations of suspended matter in the nepheloid layer. This hypothesis is supported by X-ray diffraction analyses on the nepheloid material collected at one station which show the same mineral assemblages as the underlying sediments.Time studies over periods of one week and one and one-half years showed large total-suspended-matter variations which indicate that non steady-state processes, primarily vertical eddy diffusion and possibly advection, are controlling the distribution of suspended matter in the nepheloid layer. 相似文献
10.
C. O'Reilly G. R. T. Jenkin M. Feely D. H. M. Alderton A. E. Fallick 《Contributions to Mineralogy and Petrology》1997,129(2-3):120-142
Fluid inclusions in granite quartz and three generations of veins indicate that three fluids have affected the Caledonian
Galway Granite. These fluids were examined by petrography, microthermometry, chlorite thermometry, fluid chemistry and stable
isotope studies. The earliest fluid was a H2O-CO2-NaCl fluid of moderate salinity (4–10 wt% NaCl eq.) that deposited late-magmatic molybdenite mineralised quartz veins (V1) and formed the earliest secondary inclusions in granite quartz. This fluid is more abundant in the west of the batholith,
corresponding to a decrease in emplacement depth. Within veins, and to the east, this fluid was trapped homogeneously, but
in granite quartz in the west it unmixed at 305–390 °C and 0.7–1.8 kbar. Homogeneous quartz δ18O across the batholith (9.5 ± 0.4‰n = 12) suggests V1 precipitation at high temperatures (perhaps 600 °C) and pressures (1–3 kbar) from magmatic fluids. Microthermometric data
for V1 indicate lower temperatures, suggesting inclusion volumes re-equilibrated during cooling. The second fluid was a H2O-NaCl-KCl, low-moderate salinity (0–10 wt% NaCl eq.), moderate temperature (270–340 °C), high δD (−18 ± 2‰), low δ18O (0.5–2.0‰) fluid of meteoric origin. This fluid penetrated the batholith via quartz veins (V2) which infill faults active during post-consolidation uplift of the batholith. It forms the most common inclusion type in
granite quartz throughout the batholith and is responsible for widespread retrograde alteration involving chloritization of
biotite and hornblende, sericitization and saussuritization of plagioclase, and reddening of K-feldspar. The salinity was
generated by fluid-rock interactions within the granite. Within granite quartz this fluid was trapped at 0.5–2.3 kbar, having
become overpressured. This fluid probably infiltrated the Granite in a meteoric-convection system during cooling after intrusion,
but a later age cannot be ruled out. The final fluid to enter the Granite and its host rocks was a H2O-NaCl-CaCl2-KCl fluid with variable salinity (8–28 wt% NaCl eq.), temperature (125–205 °C), δD (−17 to −45‰), δ18O (−3 to + 1.2‰), δ13CCO2 (−19 to 0‰) and δ34Ssulphate (13–23‰) that deposited veins containing quartz, fluorite, calcite, barite, galena, chalcopyrite sphalerite and pyrite (V3). Correlations of salinity, temperature, δD and δ18O are interpreted as the result of mixing of two fluid end-members, one a high-δD (−17 to −8‰), moderate-δ18O (1.2–2.5‰), high-δ13CCO2 (> −4‰), low-δ34Ssulphate (13‰), high-temperature (205–230 °C), moderate-salinity (8–12 wt% NaCl eq.) fluid, the other a low-δD (−61 to −45‰), low-δ18O (−5.4 to −3‰), low-δ13C (<−10‰), high-δ34Ssulphate (20–23‰) low-temperature (80–125 °C), high-salinity (21–28 wt% NaCl eq.) fluid. Geochronological evidence suggests V3 veins are late Triassic; the high-δD end-member is interpreted as a contemporaneous surface fluid, probably mixed meteoric
water and evaporated seawater and/or dissolved evaporites, whereas the low-δD end-member is interpreted as a basinal brine
derived from the adjacent Carboniferous sequence. This study demonstrates that the Galway Granite was a locus for repeated
fluid events for a variety of reasons; from expulsion of magmatic fluids during the final stages of crystallisation, through
a meteoric convection system, probably driven by waning magmatic heat, to much later mineralisation, concentrated in its vicinity
due to thermal, tectonic and compositional properties of granite batholiths which encourage mineralisation long after magmatic
heat has abated.
Received: 3 April 1996 / Accepted: 5 May 1997 相似文献