Petrogenesis of Eagle Lake Granite and Its Associated Cu–Mo–Au Mineralization, Southwestern New Brunswick, Canada

The NE-trending multiphase Late Devonian Eagle Lake granite (ELG) in southwestern New Brunswick is mineralized, consisting of hypabyssal porphyritic stocks and dikes that intruded Silurian metabasic volcanic rocks; however, its various phases, ages, associations with notable stockwork Cu–Mo–Au mineralization alteration have yet to been studied. ELG suite predominantly composed phenocrysts a microcrystalline groundmass quartz, K-feldspar, plagioclase, minor biotite accessory minerals. In situ LA ICP-MS U–Pb zircon dating this pluton yielded 360 ± 5 Ma (Late Devonian), so considered part the granitic series Brunswick. isotopic analysis two samples an initial 143Nd/144Nd 0.512164 0.512184, 87Sr/86Sr 0.70168 0. 70675, 176Hf/177Hf 0.282619 0.282631. εNd (360 Ma) −0.37 +0.03, whereas εHf values are +2.1 +2.5. Pb 206Pb/204Pb 18.49 18.72, 207Pb/204Pb 15.62 15.63, 208Pb/204Pb 38.26 38.37, indicative relatively radiogenic source contaminating primitive mantle melt. Potassic pyrite-quartz veining evident some parts these porphyries. Petrographic geochemical evidence indicates composite low-T, I-type saturation temperatures between 720° 825 °C, emplacement depths 10.3 4.4 km. was emplaced along major structural trend manifested by contemporaneous faults shear zones, i.e., Belleisle Fault Zone southern