New phase relations in the Cu-Fe-S system at 800C; constraint of fractional crystallization of a sulfide liquid

2004 ◽  
Vol 2004 (10) ◽  
pp. 433-444 ◽  
Author(s):  
Tomoyuki Tsujimura ◽  
Arashi Kitakaze
Keyword(s):  
Fractional Crystallization ◽  
Phase Relations ◽  
Sulfide Liquid ◽  
New Phase

Partition coefficients for Ni, Cu, Pd, Pt, Rh, and Ir between monosulfide solid solution and sulfide liquid and the formation of compositionally zoned Ni – Cu sulfide bodies by fractional crystallization of sulfide liquid

1997 ◽  
Vol 34 (4) ◽  
pp. 366-374 ◽  
Author(s):  
Sarah-Jane Barnes ◽  
E. Makovicky ◽  
M. Makovicky ◽  
J. Rose-Hansen ◽  
S. Karup-Moller
Keyword(s):  
Solid Solution ◽  
Sulfur Content ◽  
Fractional Crystallization ◽  
Copper Sulfide ◽  
Partition Coefficients ◽  
Crystal Fractionation ◽  
Sulfide Liquid ◽  
Monosulfide Solid Solution ◽  
Experimental Systems ◽  
Nickel Copper

Many nickel–copper sulfide orebodies contain Cu- and Fe-rich portions. The Fe-rich ore is generally richer in Os, Ir, Ru, and Rh and poorer in Pt, Pd, and Au than the Cu-rich ore. In komatiite-hosted ores Ni tends to be concentrated in the Cu-rich ore, whereas in tholeiitic ores it tends to be concentrated in the Fe-rich ore. The origin of this zonation could be due to crystal fractionation of Fe-rich monosulfide solid solution from a sulfide liquid. The crystal fractionation would produce an Fe-rich cumulate enriched in Os, Ir, Ru, and Rh and a fractionated liquid enriched in Cu, Pt, Pd, and Au. This model can be tested for zoned orebodies by applying experimentally determined partition coefficients for the metals into monosulfide solid solution. We have compared our experimental results with those of other workers to show that the partition coefficients are strongly influenced by the sulfur content of the system. There is a positive correlation between the partition coefficients and sulfur content of the monosulfide solid solution and between the partition coefficients and the sulfur content of the liquid. In sulfur-saturated and sulfur-over-saturated experimental systems, the metals behave in a manner consistent with the model, that is, Os, Ir, Ru, and Rh are compatible with monosulfide solid solution, Cu, Pd, and Pt are incompatible, and Ni has a partition coefficient close to 1. The use of the experimental partition coefficients is demonstrated in the numerical modelling of a zoned komatiite-related ore (Alexo, Abitibi Greenstone Belt) and a zoned tholeiite-related ore (Oktyabr'sky, Noril'sk region, Siberia). In both cases, the experimental partition coefficients numerically model the composition zones of the actual ores. This supports the model of fractional crystallization of a monosulfide solid solution from a sulfide liquid to form zoned orebodies. Furthermore, it indicates that the experimentally determined partition coefficients are geologically reasonable.

Stability and phase relations of Ca[ZnSi3]O8, a new phase with feldspar structure in the system CaO-ZnO-SiO2

2001 ◽  
Vol 86 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
Karl Thomas Fehr ◽  
Alexandra L. Huber
Keyword(s):  
Phase Relations ◽  
New Phase

Equilibria in the Mg-rich part of the pyroxene quadrilateral

1983 ◽  
Vol 47 (343) ◽  
pp. 153-160 ◽  
Author(s):  
G. A. Jenner ◽  
D. H. Green
Keyword(s):  
High Temperature ◽  
Invariant Point ◽  
Volcanic Rocks ◽  
Experimental Studies ◽  
Temperature Stability ◽  
Phase Relations ◽  
Stability Field ◽  
High Temperature Stability ◽  
Experimental Findings ◽  
New Phase

AbstractPyroxene phase relations in the Mg-rich corner of the pyroxene quadrilateral, at 1 atmosphere, have been reinvestigated. Experimental studies on sixteen selected compositions in the systems CMS and CFMS were undertaken in the temperature range 1100–1400 °C. The results of this study clarify our understanding of the pyroxene stability relations at low pressure. In particular, the demonstration that there is a high-temperature stability field of orthoenstatite denies the existence of a stable (or real) invariant point defined by the reactions OE = PE + DI, PE + DI = PI, and OE + DI = PI, in the system CaMgSi2O6-Mg2Si2O6. New phase relations, consistent with the experimental findings of this and other studies, for the Mg-rich corner of the pyroxene quadrilateral are presented. These new phase relations may be of use in interpreting the origin of volcanic rocks containing magnesian pigeonite.

Magnetite Chemistry by LA-ICP-MS Records Sulfide Fractional Crystallization in Massive Nickel-Copper-Platinum Group Element Ores from the Norilsk-Talnakh Mining District (Siberia, Russia): Implications for Trace Element Partitioning into Magnetite

2020 ◽  
Vol 115 (6) ◽  
pp. 1245-1266 ◽  
Author(s):  
Charley J. Duran ◽  
Sarah-Jane Barnes ◽  
Eduardo T. Mansur ◽  
Sarah A.S. Dare ◽  
L. Paul Bédard ◽  
...  
Keyword(s):  
Solid Solution ◽  
Fractional Crystallization ◽  
Platinum Group Element ◽  
Group Element ◽  
Sulfide Liquid ◽  
Mining District ◽  
Monosulfide Solid Solution ◽  
Sulfide Deposits ◽  
Chalcophile Elements ◽  
Platinum Group

Abstract Mineralogical and chemical zonations observed in massive sulfide ores from Ni-Cu-platinum group element (PGE) deposits are commonly ascribed to the fractional crystallization of monosulfide solid solution (MSS) and intermediate solid solution (ISS) from sulfide liquid. Recent studies of classic examples of zoned orebodies at Sudbury and Voisey’s Bay (Canada) demonstrated that the chemistry of magnetite crystallized from sulfide liquid was varying in response to sulfide fractional crystallization. Other classic examples of zoned Ni-Cu-PGE sulfide deposits occur in the Norilsk-Talnakh mining district (Russia), yet magnetite in these orebodies has received little attention. In this contribution, we document the chemistry of magnetite in samples from Norilsk-Talnakh, spanning the classic range of sulfide composition, from Cu poor (MSS) to Cu rich (ISS). Based on textural features and mineral associations, four types of magnetite with distinct chemical composition are identified: (1) MSS magnetite, (2) ISS magnetite, (3) reactional magnetite (at the sulfide-silicate interface), and (4) hydrothermal magnetite (resulting from sulfide-fluid interaction). Compositional variability in lithophile and chalcophile elements records sulfide fractional crystallization across MSS and ISS magnetites and sulfide interaction with silicate minerals (reactional magnetite) and fluids (hydrothermal magnetite). Estimated partition coefficients for magnetite in sulfide systems are unlike those in silicate systems. In sulfide systems, all lithophile elements are compatible and chalcophile elements tend to be incompatible with magnetite, but in silicate systems some lithophile elements are incompatible and chalcophile elements are compatible with magnetite. Finally, comparison with magnetite data from other Ni-Cu-PGE sulfide deposits pinpoints that the nature of parental silicate magma, degree of sulfide evolution, cocrystallizing phases, and alteration conditions influence magnetite composition.

Electron microscopy of niobium and tantalum hydrides

1978 ◽  
Vol 36 (1) ◽  
pp. 644-645
Author(s):  
T. Schober
Keyword(s):  
Electron Microscopy ◽  
Heat Storage ◽  
Measurement Techniques ◽  
Metal Hydrides ◽  
Detailed Understanding ◽  
Storage Devices ◽  
Unit Cells ◽  
Endothermic Reactions ◽  
Hydrogen Reactions ◽  
New Phase

Nb, Ta and V are prototype substances for the study of the endothermic reactions of H with metals. Such metal-hydrogen reactions have gained increased importance due to the application of metal-hydrides in hydrogen- und heat storage devices. Electron microscopy and diffraction were demonstrated to be excellent methods in the study of hydride morphologies and structures (1). - Figures 1 and 2 show the NbH and TaH phase diagrams (2,3,4). EM techniques have contributed substantially to the elucidation of the structures and domain configurations of phases β, ζ and ε (1,4). Precision length measurement techniques of distances in reciprocal space (5) recently led to a detailed understanding of the distortions of the unit cells of phases ζ and ε (4). In the same work (4) the existence of the new phase η was shown. It is stable near -68 °C. The sequence of transitions is thus below 70 %.

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