Mineralogy, mineral chemistry, and genesis of precious metal-bearing volcanogenic massive sulfide deposits in the Newfoundland Appalachians, Canada: the Ming deposit as example

The Ming deposit, Newfoundland Appalachians, is a metamorphosed (upper greenschist to lower amphibolite facies), Cambro-Ordovician, bimodalmafic volcanogenic massive sulfide (VMS) deposit that consists of several, spatially-associated, elongated orebodies composed of stratabound semimassive to massive sulfides and/or discordant sulfide stringers in a rhyodacitic footwall. Copper is the main commodity; however, the deposit contains precious metal-bearing zones with elevated Au grades. In this study, field observations, microscopy, and micro-analytical tools including electron microprobe, laser ablation inductively coupled plasma mass spectrometry, and secondary ion mass spectrometry were used to constrain the relative timing of precious metal emplacement, the physico-chemical conditions of hydrothermal fluid precipitation, and the sources of sulfur, precious metals, semi-metals and metals. The ore mineral assemblage is complex and indicates an intermediate sulfidation state. Pyrite and chalcopyrite are the dominant ore minerals with minor sphalerite and pyrrhotite, and trace galena, arsenopyrite and cubanite. Additional trace phases include tellurides, NiSb phases, sulfosalts, electrum, AgHg±Au alloys, and oxides. Silver phases and precious metals occur predominantly in semi-massive and massive sulfides as free grains, and as grains spatially associated with arsenopyrite and/or sulfosalts. Precious metal phases occurring between recrystallized pyrite and within cataclastic pyrite are rare. Hence, the complex ore assemblage and textures strongly suggest syngenetic precious metal emplacement, whereas metamorphism and deformation only internally and locally remobilized precious metal phases. The ore assemblage formed from reduced, acidic hydrothermal fluids over a range of temperatures (≈350 to below 260ºC). The abundance of telluride and Ag-bearing tetrahedrite, however, varies strongly between the different orebodies indicating variable ƒTe₂, ƒSe₂, mBi, and mSb within the hydrothermal fluids. The variations in the concentrations of semi-metals and metals (As, Bi, Hg, Sb, Se, Te), as well as Au and Ag, were due to variations in temperature but also to a likely contribution of magmatic fluids into the VMS hydrothermal system from presumably different geothermal reservoirs. Sulfur isotope studies indicate at least two sulfur sources: sulfur from thermochemically-reduced seawater sulfate and igneous sulfur. The source of igneous sulfur is the igneous footwall, direct magmatic fluid/volatiles, or both. Upper greenschist to lower amphibolite metamorphic conditions and deformation had no significant effect on the sulfur isotope composition of the sulfides at the Ming deposit.

Educational Videos and Exposure to Nature as Predictors of Environmentally Responsible Behaviours among University Students

The purpose of this study was to examine if the effects of exposure to educational videos on climate change and exposure to a view of nature could elicit environmentalist behaviours and increase one’s environmental identity. It was predicted that participants who were exposed to a view of nature and saw a video on climate change would have a higher likelihood to plant a seed and experience greater connectedness to nature. Fifty-four students (38 females, 15 males, and 1 gender fluid) with ages ranging from 18 to 47 were recruited for the experiment. A 2 (type of video) x 2 (type of view) factorial design was conducted, in which participants were randomly assigned to watch either an educational video on climate change or on popsicles, and they either had a view of outdoors or indoors. There was no significant interaction for setting and video (p = .172) on whether participants chose to plant a seed or not. Likewise, there was no significant interaction for setting and video (p = .262) on planting intentions. There was a significant effect for the video on experiencing connection to nature (p = .039, ηp2 = .08). These findings suggest that this video could change one’s perception of nature.