Crustal geochemistry in the Wawa–Foleyet region, Ontario

1994 ◽  
Vol 31 (7) ◽  
pp. 1104-1121 ◽  
Author(s):  
D. M. Shaw ◽  
A. P. Dickin ◽  
H. Li ◽  
R. H. McNutt ◽  
H. P. Schwarcz ◽  
...  
Keyword(s):  
Low Temperature ◽  
Continental Crust ◽  
Major Elements ◽  
Chemical Compositions ◽  
Transition Elements ◽  
Aqueous Alteration ◽  
Clastic Sediments ◽  
Greenstone Belts ◽  
Regional Abundance ◽  
Fluid Homogenization

Fifty-three rock samples from the Kapuskasing structural zone (KSZ) and 56 from the Wawa domal gneiss terrane (WGT), Ontario, have been analysed for major elements, 32 trace elements, and δ18O; δD was measured in a few samples.Average chemical compositions for the KSZ and WGT regions have been calculated from map unit averages weighted by regional abundance. Compared with estimates of the composition of the upper continental crust (UCC), the KSZ is enriched in Al, Fe, Mg, Ca, P, transition elements, Sc, and Sr; depleted in Si, B, most rare earth elements, Zr, Hf, Nb, Ta, Li, Na, K, U, Th, Ba, and Rb; but similar in composition to estimates of the lower continental crust. The WGT is closer in composition to the UCC. These data support the interpretation, on geophysical and petrological grounds, that the crust here is layered and has been uplifted, the WGT and KSZ regions representing progressively deeper levels.Igneous rock and orthogneiss δ18O values in the KSZ and WGT show good correlation with the weight percentages of SiO2. Paragneisses and clastic sediments and metavolcanics in the Michipicoten greenstone belt have higher ratios, as in other greenstone belts. Low δ18O and high δD values in most of the higher grade mafic gneisses show that they have never undergone low-temperature marine alteration. However, a few mafic gneisses with relict pillows show δ18O and δD values indicating low-temperature aqueous alteration. The δ18O and δD evidence throughout the two regions supports the view that no regional fluid homogenization took place.Errorchron ages of 2725 ± 130 Ma (Rb/Sr) and 2755 ± 110 Ma (Sm/Nd) were obtained for tonalite–granodiorite gneiss and agree within error with results from other workers. The intrusive Floranna Lake complex is 2580 ± 120 Ma (Rb/Sr), not significantly different from the age of the tonalite. Scatter in the data is to be attributed to localized late-stage alteration under low water–rock ratios by Sr-rich–Rb-poor brines. Model Nd ages suggest that there is no old crust [Formula: see text] in the region and that the 2700 Ma mantle was depleted relative to the bulk earth.

scholarly journals The fractionation of the elements in river waters with respect to the continental crust: a UK perspective based on a river enrichment factor approach

2000 ◽  
Vol 4 (3) ◽  
pp. 499-509 ◽  
Author(s):  
C. Neal
Keyword(s):  
Enrichment Factor ◽  
Continental Crust ◽  
Chemical Elements ◽  
Water Concentration ◽  
Base Cations ◽  
Major Elements ◽  
Transition Elements ◽  
River Waters ◽  
Order Of Magnitude ◽  
The Uk

Abstract. The fractionation in chemical elements for UK river waters is described relative to the continental crust based on data collected within studies of upland acidic catchments in mid-Wales and major eastern-UK rivers. Four types of river are examined (upland, rural, agricultural and industrial/urban) together with an average for the UK based on a "river enrichment factor", REF. Here, the REF is defined as the ratio of the median river water concentration to the average abundance for the upper continental crust for each element. For this purpose, graphical representations of the logarithm of the REF are presented sequentially in increasing order of magnitude. The results demonstrate vividly the high fractionating of the more volatile, anionic and ‘sea-salt' elements to the aqueous phase and the retention of transition elements of high charge due to solubility controls with intermediate controls for the divalent base cations of intermediate solubility. They also show the increasing significance of pollutants in the agriculturally and industrially/ urban impacted environments. Keywords: Elements; major elements; trace elements; nutrients; river; hydrochemistry; enrichment factor; river enrichment factor; LOIS; Plynlimon; River Severn; Afon Hafren; River Tweed; River Aire; River Thames

Electron microprobe study of turquoise-group solid solutions in the Neyshabour and Meydook mines, northeast and southern Iran

2020 ◽  
Vol 58 (1) ◽  
pp. 71-83
Author(s):  
Elahe Mansouri Gandomani ◽  
Nematollah Rashidnejad-Omran ◽  
Amir Emamjomeh ◽  
Pietro Vignola ◽  
Tahereh Hashemzadeh
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Electron Microprobe ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Major Elements ◽  
Point Of View ◽  
Chemical Compositions ◽  
Light Blue ◽  
Quaternary Solid Solution

ABSTRACT Turquoise, CuAl6(PO4)4(OH)8·4H2O, belongs to the turquoise group, which consists of turquoise, chalcosiderite, aheylite, faustite, planerite, and UM1981-32-PO:FeH. In order to study turquoise-group solid solutions in samples from the Neyshabour and Meydook mines, 17 samples were selected and investigated using electron probe microanalysis. In addition, their major elements were compared in order to evaluate the feasibility of distinguishing the provenance of Persian turquoises. The electron microprobe data show that the studied samples are not constituted of pure turquoise (or any other pure endmember) and belong, from the chemical point of view, to turquoise-group solid solutions. In a turquoise–planerite–chalcosiderite–unknown mineral quaternary solid solution diagram, the chemical compositions of the analyzed samples lie along the turquoise–planerite line with minor involvement of chalcosiderite and the unknown mineral. Among light blue samples with varying hues and saturations from both studied areas, planerite is more abundant among samples from Meydook compared with samples from Neyshabour. Nevertheless, not all the light blue samples are planerite. This study demonstrates that distinguishing the deposit of origin for isochromatic blue and green turquoises, based on electron probe microanalysis method and constitutive major elements, is not possible.

scholarly journals Low temperature aqueous alteration of basalt: Mineral assemblages of Deccan basalts and implications for Mars

2012 ◽  
Vol 117 (E11) ◽  
pp. n/a-n/a ◽  
Author(s):  
R. N. Greenberger ◽  
J. F. Mustard ◽  
P. S. Kumar ◽  
M. D. Dyar ◽  
E. A. Breves ◽  
...  
Keyword(s):  
Low Temperature ◽  
Aqueous Alteration ◽  
Mineral Assemblages

Chlorite crystallinity as an indicator of metamorphic grade of low-temperature meta-igneous rocks: a case study from the Bükk Mountains, Northeast Hungary

Clay Minerals ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 205-222 ◽  
Author(s):  
P. Árkai ◽  
D. Sadek Ghabrial
Keyword(s):  
Low Temperature ◽  
Electron Microprobe ◽  
Metamorphic Grade ◽  
Igneous Rocks ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Facies Classification ◽  
Increasing Temperature ◽  
Relative Differences

AbstractX-ray diffraction chlorite crystallinity (ChC) indices and major element chemical compositions of chlorites and bulk rocks were determined and correlated in meta-igneous rocks from different Mesozoic formations in various tectonic units of the Bükk Mountains, NE Hungary. The rocks, of basic to acidic compositions, range from ocean-floor metamorphic prehnite-pumpellyite facies (diagenetic zone) through regional metamorphic prehnite-pumpellyite facies (anchizone) up to the regional metamorphic pumpellyite-actinolite and greenschist facies (epizone). As in the case of meta-sedimentary rocks, chlorite crystallinity can be applied as an empirical, complementary petrogenetic tool to determine relative differences in grades of low-temperature meta-igneous rocks. Electron microprobe and XRD data show that ChC is controlled mainly by the decreasing amounts of contaminants (mixed-layered components or discrete, intergrown phases of mostly smectitic composition) in chlorite with advancing metamorphic grade, up to the epizone. The apparent increase in calculated Aliv content of chlorite with increasing temperature is related to the decrease of these contaminants, as stated earlier by Jiang et al. (1994). On the basis of the significant correlations found between ChC and temperatures, derived by the chlorite-Aliv geothermometer of Cathelineau (1988), both methods may be used for estimating the approximate temperatures of metamorphism, in spite of the contrasting interpretation of chemical data from chlorites obtained by electron microprobe analyses. After determining the effects of changing bulk chemistry on chlorite composition and ChC, the chlorite crystallinity method may complement the correlation of the illite crystallinity-based zonal classification of meta-sediments and the mineral facies classification of meta-igneous rocks.

scholarly journals Fluid chemistry of the low temperature hyperalkaline hydrothermal system of Prony Bay (New Caledonia)

2014 ◽  
Vol 11 (20) ◽  
pp. 5687-5706 ◽  
Author(s):  
C. Monnin ◽  
V. Chavagnac ◽  
C. Boulart ◽  
B. Ménez ◽  
M. Gérard ◽  
...  
Keyword(s):  
Low Temperature ◽  
Marine Environment ◽  
Water Samples ◽  
Hydrothermal System ◽  
New Caledonia ◽  
Water Discharge ◽  
The Other ◽  
Chemical Compositions ◽  
Saturation State ◽  
High Ph

Abstract. The terrestrial hyperalkaline springs of Prony Bay (southern lagoon, New Caledonia) have been known since the nineteenth century, but a recent high-resolution bathymetric survey of the seafloor has revealed the existence of numerous submarine structures similar to the well-known Aiguille de Prony, which are also the location of high-pH fluid discharge into the lagoon. During the HYDROPRONY cruise (28 October to 13 November 2011), samples of waters, gases and concretions were collected by scuba divers at underwater vents. Four of these sampling sites are located in Prony Bay at depths up to 50 m. One (Bain des Japonais spring) is also in Prony Bay but uncovered at low tide and another (Rivière des Kaoris spring) is on land slightly above the seawater level at high tide. We report the chemical composition (Na, K, Ca, Mg, Cl, SO4, dissolved inorganic carbon, SiO2(aq)) of 45 water samples collected at six sites of high-pH water discharge, as well as the composition of gases. Temperatures reach 37 °C at the Bain des Japonais and 32 °C at the spring of the Kaoris. Gas bubbling was observed only at these two springs. The emitted gases contain between 12 and 30% of hydrogen in volume of dry gas, 6 to 14% of methane, and 56 to 72% of nitrogen, with trace amounts of carbon dioxide, ethane and propane. pH values and salinities of all the 45 collected water samples range from the seawater values (8.2 and 35 g L−1) to hyperalkaline freshwaters of the Ca-OH type (pH 11 and salinities as low as 0.3 g L−1) showing that the collected samples are always a mixture of a hyperalkaline fluid of meteoric origin and ambient seawater. Cl-normalized concentrations of dissolved major elements first show that the Bain des Japonais is distinct from the other sites. Water collected at this site are three component mixtures involving the high-pH fluid, the lagoon seawater and the river water from the nearby Rivière du Carénage. The chemical compositions of the hyperalkaline endmembers (at pH 11) are not significantly different from one site to the other although the sites are several kilometres away from each other and are located on different ultramafic substrata. The very low salinity of the hyperalkaline endmembers shows that seawater does not percolate through the ultramafic formation. Mixing of the hyperalkaline hydrothermal endmember with local seawater produces large ranges and very sharp gradients of pH, salinity and dissolved element concentrations. There is a major change in the composition of the water samples at a pH around 10, which delimitates the marine environment from the hyperalkaline environment. The redox potential evolves toward negative values at high pH indicative of the reducing conditions due to bubbling of the H2-rich gas. The calculation of the mineral saturation states carried out for the Na-K-Ca-Mg-Cl-SO4-DIC-SiO2-H2O system shows that this change is due to the onset of brucite formation. While the saturation state of the Ca carbonates over the whole pH range is typical of that found in a normal marine environment, Mg- and Mg-Ca carbonates (magnesite, hydromagnesite, huntite, dolomite) exhibit very large supersaturations with maximum values at a pH of around 10, very well marked for the Bain des Japonais, emphasizing the role of water mixing in mineral formation. The discharge of high-pH waters of meteoric origin into the lagoon marine environment makes the hydrothermal system of Prony Bay unique compared to other low temperature serpentinizing environments such as Oman (fully continental) or Lost City (fully marine).

scholarly journals TEM observation for low-temperature grown spinel-type LiMn2O4crystals

2014 ◽  
Vol 70 (a1) ◽  
pp. C749-C749
Author(s):  
Kunio Yubuta ◽  
Yusuke Mizuno ◽  
Nobuyuki Zettsu ◽  
Shigeki Komine ◽  
Kenichiro Kami ◽  
...  
Keyword(s):  
Low Temperature ◽  
Manganese Oxides ◽  
Low Cost ◽  
Active Material ◽  
Lithium Ion ◽  
Growth Conditions ◽  
Rechargeable Batteries ◽  
Chemical Compositions ◽  
Spinel Type ◽  
Average Size

Present spinel-type lithium manganese oxides have attracted much attention as positive-electrode active materials for lithium-ion rechargeable batteries, which are the most sought-after power source for various electric applications, because of their low cost, non-toxicity, and high abundance of source materials compared to the conventionally used LiCoO2 crystals. Spinel-type LiMn2O4 crystals were grown at low-temperature by using a LiCl-KCl flux. The chemical compositions, sizes, and shapes of the LiMn2O4 crystals could be tuned by simply changing the growth conditions. Among the various products, the crystals grown at a low temperature of 873 K showed a small average size of 200 nm. Electron diffraction patterns and TEM images reveal the truncated octahedral shape of the crystals. The flux growth driven by rapid cooling resulted in truncated octahedral LiMn2O4 crystals surrounded by both dominating {111} and minor {100} faces with {311} and {220} edges. Lattice images indicate that crystals grown at a lower temperature have the excellent crystallinity. The small LiMn2O4 crystals grown at 873 K showed better rate properties than the large crystals grown at 1173 K, when used as a positive active material in lithium-ion rechargeable batteries.

scholarly journals Manufacturing technologies of steel seamless tubes for production of hard-to-recover hydrocarbons

2018 ◽  
Vol 61 (11) ◽  
pp. 866-875
Author(s):  
A. G. Shiryaev ◽  
S. G. Chetverikov ◽  
S. G. Chikalov ◽  
I. Yu. Pyshmintsev ◽  
P. V. Krylov
Keyword(s):  
Carbon Dioxide ◽  
Heat Treatment ◽  
Low Temperature ◽  
Hot Rolling ◽  
Cast Steel ◽  
High Strength ◽  
Pipe Plant ◽  
Chemical Compositions ◽  
High Hardenability ◽  
Technical Requirements

The review contains main directions in the development of modern steelmaking, hot rolling technologies and heat treatment aimed to follow increased requirements to seamless tubes for production of oil and gas under severe conditions. New targets of PJSC “Gazprom” in development of new resources have determined new technical requirements to pipes for low temperature application, resistant to hydrogen sulfide and carbon dioxide corrosion. Basic metal science approaches are given to develop new chemical compositions of high quality steels containing minimum of sulfur, phosphorous and solute gases. Corresponding heat treatment routes are determined for formation of martensitic microstructure in full wall section during quenching with subsequent high tempering for required combination of high strength and ductility. It was shown that optimal combination of high strength and toughness at 60 °C below zero can be achieved by alloying of chromium-molybdenum steel containing about 0.25 wt. % of carbon with strong carbon forming elements such as vanadium and niobium. Sustainability of these steels to stress sulfide cracking was achieved through grain refinement with microalloying by molybdenum in concentrations corresponding to strength grades that gives high hardenability and retards tempering of martensite. New compositions of corrosion resistant martensitic 13 % chromium steel were carried out that was resulted in required resistance to carbon dioxide environments with improved low temperature toughness and high strength. The authors present results of reconstruction of steel making and hot rolling production lines at JSC “Volzhskii Pipe Plant” providing the required quality of new products from continuously cast steel billets to finished tubes.

scholarly journals Investigation of Reagents with Different Chemical Compositions for Protection of Oil Primary Refining Equipment

2010 ◽  
Vol 4 (3) ◽  
pp. 231-236
Author(s):  
Petro Topilnytsky ◽  
◽  
Victoria Romanchuk ◽  
Keyword(s):  
Low Temperature ◽  
Corrosion Inhibitors ◽  
Phase System ◽  
Chemical Compositions ◽  
Polar Solvents ◽  
Two Phase ◽  
Nitrogen Containing Compounds ◽  
Refining Equipment

The article deals with the investigation results of nitrogen-containing compounds solubility in non-polar and polar solvents, as well as low-temperature properties of formed solutions and their anticorrosive properties as corrosion inhibitors in the hydrocarbon-water two-phase system.

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