A study of the till indicator mineral and matrix geochemical signature of the Mount Pleasant W-Mo-Bi and Sn-Zn-In deposits in New Brunswick, Canada was undertaken using commercially available methods. Indicator minerals of the deposits include: cassiterite, wolframite, and molybdenite, as well as gangue minerals topaz, chalcopyrite, galena, sphalerite, arsenopyrite, pyrite, and loellingite and secondary Pb minerals beudantite, anglesite, plumboferrite, and plumbogummite in the 0.25–0.5 mm heavy mineral (> 3.2 specific gravity) fraction, and fluorite in the 0.25–0.5 mm mid-density (3.0–3.2 specific gravity) fraction. The presence of coarse (0.5–2.0 mm) indicator minerals in till close (< 1 km) to the deposits marks the close proximity to mineralization. Indicator elements in the < 0.063 mm fraction of till overlying and down ice of the deposits include Sn, W, Mo, Bi, Zn, and In. Pathfinder elements in till include Ag, As, Cd, Cu, Pb, Re, Te, and Tl. This study reports In values of < 0.02 to 13 ppm in the matrix of till overlying the deposit; values > 5 ppm are some of the highest ever reported for till.

A study of indicator minerals in bedrock was carried out at the Mount Pleasant Sn-W-Mo-Bi-In deposit, in New Brunswick. This study was conducted as part of the Geological Survey of Canadamp;gt;'s (GSC) Targeted Geoscience Initiative 4 (TGI-4). It included mineralogical identification of polished thin sections and of heavy mineral concentrates produced from disaggregated bedrock samples. Indicator minerals identified in bedrock samples include the main ore minerals, cassiterite, molybdenite and sphalerite, as well as chalcopyrite, pyrite, galena, arsenopyrite, fluorite, and topaz. Although the deposit is well known for its wolframite content, it was not found in any of the rocks examined in this study. This absence is likely due to the small number of bedrock samples examined in this study.

(2007). Petrochemical discrimination of evolved granitic intrusions associated with Mount Pleasant deposits, New Brunswick, Canada by C. M. C. Inverno and R. W. Hutchinson. Applied Earth Science: Vol. 116, Geology of Uranium Deposits, pp. 106-111.

Developments in computer software have facilitated the construction and enhancement of a GIS (Geographic Information Systems) data set of highly generalized geology of the world and related data sets on various types of mineral deposits. The GIS and mineral deposit data sets can be linked and processed using GIS software for computer display and cartographic products. Although the complete data sets are too large to be usefully displayed at any one time, selected themes such as mineral deposits and genetically related magmatic rocks can be extracted to help visualize global scale patterns. For example, porphyry, porphyry-associated skarn, and bulk-tonnage epithermal deposits can be displayed on a background of felsic and/or intermediate intrusive and extrusive magmatic rocks. Nickel deposits, on the other hand, can be shown relative to the distribution of mafic and/or ultramafic intrusive and extrusive magmatic rocks. These and other thematic products have a wide range of applications including mineral exploration planning, mineral resource assessment, mineral policy development, mineral deposits research and general education.

ABSTRACT:Comb-layered quartz is a type of unidirectional solidification texture found at the roofs of shallow silicic intrusions that are often associated spatially with Mo and W mineralisation. The texture consists of multiple layers of euhedral, prismatic quartz crystals (Type I) that have grown on subplanar aplite substrates. The layers are separated by porphyritic aplite containing equant phenocrysts of quartz (Type II), which resemble quartz typical of volcanic rocks and porphyry intrusions. At Logtung, Type I quartz within comb layers is zoned with respect to a number of trace elements, including Al and K. Concentrations of these elements as well as Mn, Ti, Ge, Rb and H are anomalous and much higher than found in Type II quartz from Logtung or in igneous quartz reported elsewhere. The two populations appear to have formed under different conditions. The Type II quartz phenocrysts almost certainly grew from a high-silica melt between 600 and 800°C (as β-quartz); in contrast, the morphology of Type I quartz is consistent with precipitation from a hydrothermal solution, possibly as α-quartz grown below 600°C. The bulk compositions of comb-layered rocks, as well as the aplite interlayers, are consistent with the hypothesis that these textures did not precipitate solely from a crystallising silicate melt. Instead, Type I quartz may have grown from pockets of exsolved magmatic fluid located between the magma and its crystallised border. The Type II quartz represents pre-existing phenocrysts in the underlying magma; this magma was quenched to aplite during fracturing/degassing events. Renewed and repeated formation and disruption of the pockets of exsolved aqueous fluid accounts for the rhythmic banding of the rocks.

This volume defines and summarizes in a comprehensive and systematic manner the essential characteristics of all economically significant types of Canadian mineral deposits. These summaries reflect the current understanding of mineral deposits and correspond closely to the definition of mineral-deposit types in common use. A large color section serves to illustrate details of some of these mineral deposits, and locations of all known deposits are presented on an oversize figure and are indexed in an appendix, as well. Like previous volumes of this type, this volume will be a long-standing premier reference for academia, industry, and government institutions alike.