The Kupol epithermal Au-Ag vein district is located in the northern part of the Okhotsk-Chukotka volcanic belt, a Late Cretaceous subduction-related continental volcanic arc exposed for >3,000 km along the eastern coast of Russia. High-grade veins are hosted in the Kupol andesite sequence, a 300- to 1,000-m-thick, subhorizontal, layered sequence of andesite flows, sills, and ash tuffs, dated at 97 to 96 Ma (Cenomanian). The Kupol andesite sequence is underlain by mixed mafic-felsic volcanic units plus sedimentary rocks (“older volcanics”) and overlain by a >1-km-thick “upper felsic” sequence of dacitic-rhyolitic tuffs and associated dikes and flow domes, dated at 95 to 85 Ma, with local sequences of fluvio-lacustrine sedimentary rocks.

The epithermal Shila-Paula Au–Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E–W vein with secondary N55–60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz–adularia– pyrite–galena–sphalerite–chalcopyrite–electrum–Mn silicate–carbonate assemblage that fills the main E–W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz–adularia–carbonate assemblage that is observed within the secondary N45–60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings.

В монографии рассмотрены многочисленные закономерности и особенности металлоносности вулканогенных поясов различного типа при особом внимании к месторождениям благородных металлов. В частности, в отдельной главе охарактеризованы эпитермальные месторождения золота и серебра в существенно обновленной интерпретации их генезиса и рудноформационных связей. Основной оригинальный материал получен при исследовании регионов окраинноморской литосферы Северо-востока Азии.

Для специалистов в области металлогении, геологии и генезиса рудных месторождений, преподавателей и студентов геологических специальностей вузов.

Субэпитермальная Au-Pd минерализация, связанная со щелочно-порфировым Cu-Au месторождением, гора Миллиган, террейн Кеснел, Британская Колумбия, Канада

At the Mount Milligan Cu-Au porphyry deposit, Quesnel terrane, British Columbia, Canada, barren and weakly mineralized, late-stage hydrothermal veins occur in volcanic rocks adjacent to zones of Cu-Au porphyry mineralization, and have overprinted the porphyry-stage veins. The earliest of the late-stage hydrothermal veins are barren and consist of quartz ± pyrite ± carbonate ± chlorite ± tourmaline. These veins are similar to “transitional” to late-stage hydrothermal veins in other alkaline porphyry Cu-Au deposits, and we consider these to be the equivalent of transitional (post-porphyry, pre-epithermal) quartz-sericite-pyrite veins in calc-alkaline porphyry environments.

The Masjed Daghi mineralization is located 30 km southeast of Jolfa city at the bank of Araxes River, northwest Iran. This area is situated in the AlborzAzarbaijan structural zone of Iran. The most widespread rocks in the mineralization area are andesite and trachyandesite, while there are rock units of latite tuff, andesitic agglomerate, and hornblende porphyry basalt in eastern hills and Eocene flysch in the southern part of the area. Several intrusive bodies are present in the study area, from which the dominant intrusive rock hosting the mineralization is diorite porphyry.

About the Special Issue Editor
Preface to ”Experimental and Thermodynamical Modeling of Ore-Forming Processes in Magmatic and Hydrothermal Systems”
Galina Palyanova Editorial for the Special Issue: Experimental and Thermodynamic Modeling of Ore-Forming Processes in Magmatic and Hydrothermal Systems Reprinted from
Alexander V. Zotov, Nikolai N. Kuzmin, Vladimir L. Reukov and Boris R. Tagirov Stability of AuCl2 − from 25 to 1000 ◦C at Pressures to 5000 bar and Consequences for Hydrothermal Gold Mobilization
Vladimir L. Tauson, Sergey V. Lipko, Nikolay V. Smagunov and Raisa G. Kravtsova Trace Element Partitioning Dualism under Mineral–Fluid Interaction: Origin and Geochemical Significance

The gold deposit at La Josefina, in the Deseado Massif of Argentina, is a low-sulfidation epithermal deposit with some features of the intermediate sulfidation style; the Au occurs in quartz veins and hydrothermal breccias hosted by acid pyroclastic rocks produced by Jurassic bimodal volcanism. Exploration for this deposit type uses geochemical data for vectoring to mineralized rocks. Although a general suite of elements with anomalous concentrations around low-sulfidation deposits is known, that suite varies amongst individual deposits, which should be studied individually.

The El Dorado Au-Cu deposit is located in an extensive intra-caldera zone of hydrothermal alteration affecting Upper Cretaceous andesites of the Los Elquinos Formation at La Serena (
29470 S Lat., 70430 W Long., Chile). Quartz-sulfide veins of economic potential are hosted by N25W and N20E fault structures associated with quartz-illite alteration (þsupergene kaolinite).