A theoretical study of hydrothermal convection and the origin of the ophiolitic sulphide ore deposits of Cyprus

1978 ◽  
Vol 40 (1) ◽  
pp. 33-44 ◽  
Author(s):  
E PARMENTIER ◽  
E SPOONER
Nature ◽  
1979 ◽  
Vol 277 (5697) ◽  
pp. 513-514 ◽  
Author(s):  
J. P. N. Bedham
Keyword(s):  

1993 ◽  
Vol 57 (389) ◽  
pp. 599-606 ◽  
Author(s):  
Martin Hale

AbstractSulphide minerals and their analogues yield gases as a result of oxidation reactions. Even where sulphide minerals are in contact with mildly reducing groundwaters, S2- ions pass into solution and their dispersion patterns can be detected in soil as acid-released H2S. In more oxidising conditions, the metastable gases COS and CS2 are generated. Anomalous dispersion patterns of COS have been reported in soils above more than ten sulphide ore deposits, many of them concealed beneath transported exotic overburden. High concentrations of CS2 occur in the soils over several of the same deposits and uniquely reflect others. Anomalies of SO2 over sulphide deposits are confined to arid terrains. Certain anomalous dispersion patterns of arsenic and tellurium in soils are attributed to the generation and migration of unspecified gases from the oxidation of arsenide and telluride minerals.


2018 ◽  
Vol 37 (9-10) ◽  
pp. 909-919
Author(s):  
C. A. Pickles ◽  
W. Anthony

AbstractThe recovery of nickel from the oxidic nickeliferous laterite ores is receiving increasing attention due to the difficulty of recovering this metal from the sulphide ore deposits. One possible solution is to selectively reduce the nickel oxide in the ore, which could then be upgraded by, for example, magnetic concentration. In this article, a thermodynamic study was performed on the reduction of a limonitic laterite ore by methane. Methane was selected as the reducing agent as it has a lower environmental impact than carbon due to the reduced carbon dioxide emissions. The effects of temperatures and methane additions on the nickel recovery and nickel grade were investigated. High recoveries of over 95 % were predicted, but the grades were limited to about 2.5 % due to the formation of magnetite. The thermodynamic simulations for reduction by methane were in agreement with the experimental results in the literature for other reducing agents, reflecting the fact that the nickel oxide in the limonitic ore is relatively unstable. Thus, high recoveries could be achieved irrespective of the reducing agent involved.


Author(s):  
Sundaram Iyer ◽  
Valiya Hamza

Representative values of fluid inclusion temperatures and radiogenic heat production values have been compiled as part of an attempt to determine paleo heat flow in areas sedimentary exhalative (SEDEX) deposits in thirteen localities of eastern Brazil. The results obtained indicate heat flow in excess of 80 mW/m2in areas of mineral bearing sulphide ore deposits, during periods of ore forming processes. Such anomalously high heat flow are more than twice the present-day values for stable tectonic units of Precambrian age. There are indications that high heat flow values were sustained by circulation of hydrothermal fluids in the upper crust, during periods not exceeding a few hundred million years. The resulting geothermal episodes may be considered as constituting short-period “heat pulses” occurring in stable tectonic environments, generated by magma emplacements in the upper crust, leading to formation of areas of sulfide ore deposits. Model simulations indicate that subsidence episodes induced by stretching and magma under-plating constitute the mechanisms for high heat flow during the ore-forming processes.


2017 ◽  
Vol 126 (2) ◽  
pp. 56-57
Author(s):  
Emily K. Fallon ◽  
Richard A. Brooker ◽  
Thomas B. Scott

Sign in / Sign up

Export Citation Format

Share Document