Tourmaline has long been regarded as a petrogenetic indicator of its host environment, but its genesis in mineralized porphyry systems is poorly understood. Based on chemical and physical properties, tourmaline possesses essential features to be an effective
indicator mineral. These properties, along with its abundant occurrence in mineralized copper-gold-molybdenum porphyry systems, make it potentially a key recorder of hydrothermal fluid composition, evolution and potential mineralization. A suite of tourmaline-bearing, barren and mineralized porphyry
samples have been analysed as part of a broader study, including those from the Canadian Cordillera (Casino, Schaft Creek, High-land Valley and Woodjam) plus others, have been studied. Paragenetically, tourmaline is observed to be an early hydrothermal phase, predating both sulphide formation and
any alteration. Tourmaline is observed to exhibit multiple growth zones, based on petrographic and electron microscope observations, which are also reflected in distinct trace-element variations. Three distinct textural types are recognized: breccia-style, vein-style and disseminated-style. Ma-jor
element analyses based on SEM-EDS show a range between schorl (Na-Fe2+-rich) to dravite (Na-Mg-rich) with some minor povondraite (Na-Fe3+) component. Trace element analyses of porphyry related tourmaline via LAM-ICP-MS show distinct characteristics in comparison to that from non-porphyry settings,
including redox sensitive elements (Mn, As and Sb) and large-ion lithophile elements (Sr, Ba). Elements not observed in significant concentrations include the light elements (Li, Be) and REEs, which commonly were below limit of detection. Current trace element analysis of tourmaline derived from
surficial sediments points to tourmaline originating from the local porphyry system rather than an external source.
In 2019, the Government of India launched the National Clean Air Program (NCAP) to address the pervasive problem of poor air quality and the burdens it creates for public health, particularly in the 122 non-attainment cities that exceed national air quality standards. In much of Northern India, achieving and sustaining air quality improvements requires coordinated efforts to prevent agricultural burning of crop residues. Historically, rice residue burning has been most prevalent in Northwestern IGP (Indo-Gangetic Plain) but the practice is rapidly expanding into the populous Eastern IGP states, including Bihar, with uncertain consequences for regional air quality. This research has three objectives: (1) characterize historical rice residue burning trends since 2002 over space and time in Bihar State, (2) project future burning trajectories to 2050 under ‘business as usual’ and alternative scenarios of change, and (3) simulate air quality outcomes under each scenario to estimate public health burdens. Historical trends were modelled and extended to mid-century burning projections, which were coupled with the Community Earth System Model (CESM v2.1.0) to characterize air quality impacts under each scenario. These analyses suggest that contemporary Bihar State burning levels contribute a small daily average proportion (8.1%) of the fine particle pollution load (i.e. PM2.5, particles < = 2.5 μm) during the burning months, but up to as much as 62% on the worst of winter days in Bihar’s capital region. With a projected 142% ‘business as usual’ increase in burning prevalence anticipated for 2050, Bihar’s capital region may experience the equivalent of 30 PM2.5 additional exceedance days, according to the WHO standard, due to rice residue burning alone in the October to December period. If historical burning trends intensify and Bihar resembles the Northwest States of Punjab and Haryana by 2050, 46 days would exceed the WHO standard for PM2.5 in Bihar’s capital region.
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