Sulphur isotope study of the Muskox Intrusion, district of Mackenzie (86J/13, O/3)

1969 ◽  
Author(s):  
A Sasaki
Keyword(s):  
Sulphur Isotope ◽  
Isotope Study

scholarly journals Sources of acidity and metals in a stream draining acid sulphate soil, till and peat, western Finland, revealed by a hydrochemical and sulphur isotope study

2008 ◽  
Vol 14 (1) ◽  
pp. 34 ◽  
Author(s):  
M. ÅSTRÖM ◽  
B. SPIRO
Keyword(s):  
Humic Acids ◽  
Low Flow ◽  
Sulphur Isotope ◽  
Acid Sulphate Soil ◽  
Acid Sulphate ◽  
Acid Sulphate Soils ◽  
Forested Areas ◽  
Alkaline Earths ◽  
Isotope Study ◽  
Water Quality Deterioration

The main aim of this study was to determine, during extreme hydrological conditions, the source(s) of acids, sulphate and metals (alkali and alkaline earths) in the Munsala stream (western Finland) draining mainly acid sulphate soil, peat and till. Samples were collected at 6 sites along the main stem on 3 high-flow and 3 low-flow events, and were analysed for the required chemical and isotopic variables. The acid sulphate soils (located under farmland) had a large impact on the stream as indicated by pH values occasionally down to 4.0, moderately to strongly increased concentrations of inorganic solutes, and a high acid SO4 2- load characterised by negative d34S(sulphate) values. In addition, the forested areas underlain mainly with till and peat released low SO4 2- but low pH waters (down to at least 4.6) during high flows, indicating the importance of humic acids in controlling the pH. These humic acids flocculated abundantly in the middle/ lower reaches as a result of interaction with acid sulphate water. Therefore, not only the farmland acid sulphate soils but also the organic-rich soils/horizons in the forested areas contribute to water-quality deterioration.;

A sulphur isotope study on selected Caledonian granites of Britain and Ireland

1990 ◽  
Vol 25 (3-4) ◽  
pp. 359-369 ◽  
Author(s):  
R. Laouar ◽  
A. J. Boyce ◽  
A. E. Fallick ◽  
B. E. Leake
Keyword(s):  
Sulphur Isotope ◽  
Isotope Study

A Sulphur Isotope Study of Iron Sulphides in the Late Precambrian Dalradian Easdale Slate Formation, Argyll, Scotland

1988 ◽  
Vol 52 (367) ◽  
pp. 483-490 ◽  
Author(s):  
A. J. Hall ◽  
A. J. Boyce ◽  
A. E. Fallick
Keyword(s):  
Sharp Increase ◽  
Regional Metamorphism ◽  
Isotopic Fractionation ◽  
Sulphur Isotope ◽  
Rapid Reduction ◽  
Late Precambrian ◽  
Framboidal Pyrite ◽  
Sulphate Sulphur ◽  
Iron Sulphides ◽  
Isotope Study

AbstractPyritic slates from the late Precambrian, Middle Dalradian Argyll Group Easdale Slate Formation, contain mainly quartz, muscovite and chlorite with variable amounts of dolomite, albite and paragonite. Slates from Easdale Island and Cuan Ferry contain pyrite porphyroblasts with δ34S = + 12 to + 16‰. The pyrite grew during a post-tectonic retrogressive event at the expense ofpyrrhotine which formed during the main regional metamorphism of the Grampian orogeny by reduction of diagenetic pyrite. Slate from Oban contains abundant diagenetic framboidal pyrite and small syn-tectonic pyrite porphyroblasts with δ34S = +22‰. This pyrite was not all reduced to pyrrhotine on metamorphism so there was little retrogressive growth of pyrite. Metamorphism appears to have homogenized local (cm scale at least) isotopic inhomogeneities and preserved an average seawater-sulphate-sulphide isotopic fractionation value. Middle Dalradian seawater-sulphate had a δ34S value of about + 35‰, so the small fractionations are appropriate for bacteriogenic reduction in bituminous sediments, the heavier sulphide in the case of the Oban slate indicating more rapid reduction of sulphate. Lower Dalradian Appin Group, Ballachulish slate contains pyrite with δ34S = +15±2‰ and is best interpreted as forming in the same manner as the Easdale slates of Easdale Island and Cuan Ferry; the sharp increase in late Precambrian ocean-sulphate sulphur isotope signature from +15 to > +30‰ therefore occurred by Lower Dalradian Appin Group times.

Sulphur-isotope geochemistry of silver–selpnarsenide vein mineralization, Cobalt, Ontario

1986 ◽  
Vol 23 (10) ◽  
pp. 1551-1567 ◽  
Author(s):  
M. D. Goodz ◽  
D. H. Watkinson ◽  
V. Smejkal ◽  
Z. Pertold
Keyword(s):  
Isotopic Composition ◽  
Isotope Fractionation ◽  
Isotope Geochemistry ◽  
Wall Rock ◽  
Sulphur Isotope ◽  
Vein Formation ◽  
Metavolcanic Rocks ◽  
Isotope Study ◽  
Vein Deposits ◽  
Sulphur Isotopic Composition

The silver–sulpharsenide vein deposits of Cobalt, Ontario, crosscut basement Archean metavolcanic rocks, Proterozoic strata, and younger Proterozoic diabase sills. A petrographic and sulphur-isotope study of the metallic minerals was initiated to assess possible genetic models of vein formation. Discrete differences exist between the sulphur-isotope compositions of basement sulphides (δ34S = + 4.0‰), brecciated wall-rock sulphides (+ 3.5‰), and vein sulphides (+ 2.3‰). The δ34S values consistently increase with distance from the vein centres. Sulphur-isotope fractionation trends are similar for all the vein deposits studied. Sulphur-isotope data suggest that sulphides were deposited between 130 and 254 °C. Based on the assumption of equilibrium between chalcopyrite and galena, the initial δ34S of the fluid was between + 5.0 and + 11.0‰. The release of sulphur during the reaction of Archean pyrite with Proterozoic formational brines to form pyrrhotite is proposed to explain the heavy sulphur isotopic composition of the fluid. This process could also have provided the Ni, Co, and As, known to be concentrated in some pyrite, that was deposited in the silver veins. Interpretation of mineral paragenesis and geothermometry indicate that temperature decreased and aS2 increased as deposition proceeded.

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