The endogranitic tin zone, Mount Pleasant, New Brunswick, Canada and its metallogenesis

Inverno, Carlos; Hutchinson, Richard W.

doi:10.1179/174327504x27224

Cited by 11 publications

(22 citation statements)

References 55 publications

(76 reference statements)

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“…The breccia matrix is comparable with a wacke siltstone. In most places, the rock is a sericitised and chloritised granule-to cobble-breccia, but may range to a sericitised and chloritised granule-to cobble breccia wacke siltstone (Inverno, 1991).…”

Section: Local Geologymentioning

confidence: 99%

“…Analyses of samples of the least altered tuff plot in the rhyolite field following the compositional classifications of Peccerillo and Taylor (1976), Winchester and Floyd (1977), and Le Bas et al (1986) and in the alkali(-feldspar) rhyolite field defined by the Streckeisen (1976Streckeisen ( , 1980 and Streckeisen and Le Maitre (1979) classifications. This tuff is best classified as a devitrified and silicified, sericitised and chloritised alkali(-feldspar) rhyolitic, lithic, crystal vitric tuff to lapilli tuff (Inverno, 1991).…”

Section: Local Geologymentioning

confidence: 99%

“…An additional NW-SE, 1 km long, tongue-shaped portion also mapped as FTZ breccia (Fig. 2) contains the topazified-silicified breccia only in the northwesternmost tip; the remainder is made up of topazifiedsilicified/chloritised breccia in places with recognisable rhyolitic tuff fragments ranging to a topazified-silicified/ chloritised brecciated rhyolitic tuff (Inverno, 1991). At depth, the topazified-silicified breccia is dominant over the chloritised variety in both the FTZ and the NZ.…”

Section: Local Geologymentioning

confidence: 99%

“…To date, only minor tin mineralisation has been found associated with the PG and GIII facies (Kooiman et al, 1986;. One of those deposits is an endogranitic tin zone (ETZ), an irregular but more or less tabular, 400 m long tin mineralised body, within the GII intrusion outline (Inverno andHutchinson, 1992a, 2004) (Fig. 2).…”

Section: Granitic Intrusionsmentioning

confidence: 99%

“…1). The caldera rocks were affected by brittle deformation, in the form of faults and fractures, and only minor ductile deformation is apparent within the caldera (Inverno, 1991;Riddell, 1962).…”

Section: Introductionmentioning

confidence: 99%

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Petrochemical discrimination of evolved granitic intrusions associated with Mount Pleasant deposits, New Brunswick, Canada

Inverno¹,

Hutchinson²

2006

Applied Earth Science

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The Mount Pleasant Sn-W-Mo-Bi-In base metal deposits that are spatially and temporarily related to multiple, Late Devonian granitic intrusions are located in southern New Brunswick, Canada. Regional rocks include a sequence of Ordovician-Silurian detrital rocks, with minor interbedded volcanic rocks, which were deformed in the Devonian Acadian orogeny. The Mount Pleasant subvolcanic-eruptive complex underlies part of a 17612 km caldera which constitutes a sequence of Upper Devonian volcanic and sedimentary rocks, intruded by subvolcanicplutonic rocks (e.g. the Mount Pleasant intrusions). Brittle deformation affected the rocks within parts of the caldera.At the Mount Pleasant, along the southwestern margin of this caldera, two mineralised zones, termed the Fire Tower Zone and the North Zone, occur within volcanic necks about 1 km apart. In both zones, multiple, successive Late Devonian granitic intrusions were emplaced into interbedded rhyolitic tuffs/sedimentary breccias overlain by rhyodacitic lavas. The volcanic necks are defined by magmatic-hydrothermal breccias. In the Fire Tower Zone, fine grained granite, granite porphyry and porphyritic granite were emplaced successively. The first is associated with porphyry type W-Mo-Bi-In mineralisation. Three successive generations of granitic intrusions (known as granites I, II and III) also occur in the North Zone. Here, similar but less expressive mineralisation occurs in granite I whereas the others are associated with several significant tin deposits.In both zones, the granitic rocks are pale, porphyritic, generally fine grained, biotitic, contain micrographic intergrowths of K-feldspar and quartz in K-feldspar phenocrysts, and are modally of alkaline-feldspar type. The granitic intrusions may be classified as crustal A-type, with intraplate, high heat production and peraluminous characteristics that are typical of a continental rift environment. Petrographic and geochemical evidence suggests that they formed under conditions of fluid saturation and undercooling. Incompatible and immobile trace element and elemental ratio data indicate that they are highly evolved tin bearing granites with a higher tin potential in the North Zone than in the Fire Tower Zone. There is no solid evidence for petrochemical equivalence between individual granites from these two zones.The endogranitic tin zone is an irregular, almost tabular, 400 m long body enclosed in granite II. The form and petrographic, mineralogical and chemical evidence as well as metal zoning show that the endogranitic tin zone is hosted in a distinct phase of granite, termed the endogranitic tin zone granite. Based on chemical data from thirty North Zone granite samples, but including only one sample from the endogranitic tin zone granite, incompatible (and immobile) trace element evidence indicates that granite III is more evolved and has a higher tin potential than granite II, and only suggests that the highest potential for tin may be found in a probable late differentiate of granite III, the endogranitic ti...

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Section: Local Geologymentioning

confidence: 99%