Porphyry to Epithermal Transition in the Altar Cu-(Au-Mo) Deposit, Argentina, Studied by Cathodoluminescence, LA-ICP-MS, and Fluid Inclusion Analysis

Apatite (U–Th)/He thermochronology and Re–Os ages in the Altar region, Central Andes (31°30′S), Main Cordillera of San Juan, Argentina: implications of rapid exhumation in the porphyry Cu (Au) metal endowment and regional tectonics

“…Metallic mineralization at the Altar Central orebody occurred through successive stages of vein formation: 1) quartz ± chalcopyrite ± pyrite veins (A veins), and 2) quartz ± molybdenite veins (B veins), both formed during early potassic alteration at high temperature and pressure, and 3) late stage veins rich in Cu sulfides and sulfosalts (E veins) that formed at low temperature equivalent or transitional to the epithermal environment (Maydagán et al 2015). In the eastern sector of the Altar deposit, the roots of an epithermal lithocap are exposed, whereas in the central orebody, epithermal veins cross cut the porphyry A and B .…”

“…In the eastern sector of the Altar deposit, the roots of an epithermal lithocap are exposed, whereas in the central orebody, epithermal veins cross cut the porphyry A and B . Fluid inclusions studies have been interpreted to suggest temperatures of 540° to 510°C and pressures of 1,000 to 800 bars for the formation of stage 2 B veins, whereas stage 3 E veins formed, under hydrostatic conditions, from 280° to 250°C fluids at pressures of 150 to 20 bars (Cioldi 2009;Maydagán et al 2015).…”

“…The deposit is described as telescoped because of the close spatial distance between the porphyry and the high sulfidation alteration systems (Aldebaran Resources 2018). Metallic mineralization at the Altar Central orebody occurred through successive stages of vein formation: 1) quartz ± chalcopyrite ± pyrite veins (A veins), and 2) quartz ± molybdenite veins (B veins), both formed during early potassic alteration at high temperature and pressures, and 3) late stage veins rich in Cu sulfides and sulfosalts (E veins) that formed at low temperatures equivalent or transitional to the epithermal environment, and cross-cut the early veins (Maydagán et al 2015). The epithermal veins are considered to be slightly younger than the porphyry veins implying that the hydrothermal system would have developed in an active tectonic environment.…”

Crystallization temperature of vein quartz at Peschanka porphyry Cu-Mo-Au deposit, Western Chukchi Peninsula, Russia: Estimation from content of paramagnetic titanium centers in quartz

“…Кварц на месторождениях порфирового типа -главный жильный минерал, формирующийся в широком диапазоне температуры от ~500 до ~200 °C, и представляет особый интерес для реконструкции условий рудоотложения. В многочисленных работах приведены результаты изучения флюидных включений в кварце разных стадий образования порфировых месторождений [Sevari et al, 2014;Jun et al, 2014;Wilkinson, 2001;Maydagán et al, 2015;Müller et al, 2010;Николаев и др., 2014]. В кварце некоторых месторождений методом масс-спектрометрии с индуктивно связанной плазмой с лазерным пробоотбором (LA-ICP-MS) и масс-спектрометрии вторичных ионов (SIMS) определено содержание Li, Ti, и Al, с помощью чего можно установить или уточнить некоторые физико-химические условия образования, а именно температуру и pH среды [Rusk et al, 2012;Maydagán et al, 2015;Müller et al, 2010].…”

Auriferous Quartz Veining Due to CO2 Content Variations and Decompressional Cooling, Revealed by Quartz Solubility, SEM-CL and Fluid Inclusion Analyses (The Linglong Goldfield, Jiaodong)

“…In hydrothermal ore deposits, quartz is the most common gangue mineral and may intergrow with metals (such as native gold) and sulfides containing metals such as copper, tin, and tungsten [6]. The veining processes of quartz and associated minerals in porphyry Cu deposits have been intensively studied and well understood with the analytical aid of cathodoluminescence (CL) petrography [7][8][9], solubility analysis [10,11], fluid inclusion [12,13], trace elements [14] and oxygen isotopic composition [15,16]. For instance, highly complex veining processes involving the deposition, dissolution, reopening, recrystallization and overgrowth of quartz and incursion of cooler and dilute meteoric waters have been discovered [8,15].…”