A general thermodynamic analysis and treatment of phases and components in the analysis of phase assemblages in multicomponent systems

Hu, Jiawen

doi:10.1007/s11430-011-4340-9

Cited by 1 publication

(1 citation statement)

References 44 publications

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“…chemography) of the quaternary system from SiO 2 and O 2 to the subspaces without SiO 2 and O 2 , respectively (Hu, 2012;Hu et al, 2011), or can be eliminated together by matrix projection (Greenwood, 1975). As a result, the quaternary system is actually equivalent to a binary system in phase diagram topology (Hu, 2012). At given temperature and pressure, the CaO-FeO-SiO 2 -O 2 system has four phases in an invariant assemblage, and three phases in a univariant assemblage.…”

Section: Structural Alteration Characteristics and Mineralize Signifimentioning

confidence: 99%

Tungsten Mineralization Processes at the Sisson Brook W‐Mo‐Cu deposit, Central New Brunswick: the Role of Formation of Titaniferous Phases at Reaction Fronts

Bustard

Zhang

McFarlane

et al. 2013

Acta Geologica Sinica (Eng)

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Sisson Brook is a large tonnage, low grade W-Mo-Cu deposit located in west-central New Brunswick, Canada (see Zhang et al., this volume). The deposit is one of several in New Brunswick associated with the intrusion of granitic plutons related to the Devonian Acadian orogeny. These deposits include Mount Pleasant (W-Mo), Lake George (Sb& W-Mo-Au), and Burnthill (W) (Ruitenberg and Fyffe, 1991). This integrated petrologic study included analysis by optical microscopy, scanning electron microscopy-backscattered electron imaging (SEM-BSE), and in-situ laser ablation inductively coupled plasma-mass spectrometry (LA ICP-MS) with the goal of determining the influences of titaniferous phases on the distribution of W mineralization. LA ICP-MS was also used to date the weakly foliated Howard Peak metadiorite with U-Pb on titanite, resulting in a 204 Pb-corrected concordantage of 432.1±1.9 Ma from a single polished thin section (n=15); this diorite hosts part of the later W-Mo-Cu veins. Mineralization of the deposit occurred at temperatures much lower than the closure temperature of 650-700° C for titanite (Sun et al., 2012), and the sample that igneous titanite grains were selected from was only weakly mineralized. Procedures used for LA ICP-MS at UNB are outlined in McFarlane and Luo (2013). A B Ilm Sch Py Ttn Pl Chl Sch Wolf Qtz Fig 1a: Reflected light image of wolframite and scheelite in quartz vein hosted in metatuff. Encasing of wolframite in scheelite indicates scheelite formed later and is consuming the wolframite under changing conditions. 1b: SEM-BSE image of scheelite inclusions (brightest spots) in ilmenite (light gray) with titanite (medium) overgrowth hosted in biotite and sericitized plagioclase. Titanite also overgrows pyrite grain indicating titanite is one of the last phases to form in the deposit. Dark spots in pyrite are polishing pits. The scheelite inclusions of this size are not visible in reflected light. ACTA GEOLOGICA SINICA (English Edition) Vol. 87 Supp. June 2013 673 A B C) W (ppm) D) U (ppm) F) W (ppm) G) U (ppm) E E Fig.2. A) Transmitted light image of magmatic titanite grain. Note metamictzone around grain and fractures within. Grain is in sericitized plagioclase and chlorite. Inclusion in titanite is apatite. Numerous fractures are visible in the grain. B) SEM-BSE image of titanite showing the zoning present in the grain. Lighter colour indicates higher atomic weight material. Regrowth textures are visible around the edges of the grain (white arrow) indicating titanite was remobilized during the formation of the deposit. C) W map of titanite grain in A showing enrichment along the grain boundary and regrowth areas which are likely the result of diffusion from mineralizing fluids. Enrichment in magmatic titanite from alteration can be as high as 60 ppm above background. D) U map of titanite grain in A showing enrichment along area of high brightness seen in SEM-BSE. U enrichment is focused more along fractures than grain boundaries as seen in W distributions. The lack of complex zoning patte...

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Section: Structural Alteration Characteristics and Mineralize Signifimentioning

confidence: 99%

Tungsten Mineralization Processes at the Sisson Brook W‐Mo‐Cu deposit, Central New Brunswick: the Role of Formation of Titaniferous Phases at Reaction Fronts

Bustard

Zhang

McFarlane

et al. 2013

Acta Geologica Sinica (Eng)

View full text Add to dashboard Cite

show abstract

A general thermodynamic analysis and treatment of phases and components in the analysis of phase assemblages in multicomponent systems

Cited by 1 publication

References 44 publications

Tungsten Mineralization Processes at the Sisson Brook W‐Mo‐Cu deposit, Central New Brunswick: the Role of Formation of Titaniferous Phases at Reaction Fronts

Tungsten Mineralization Processes at the Sisson Brook W‐Mo‐Cu deposit, Central New Brunswick: the Role of Formation of Titaniferous Phases at Reaction Fronts

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