Recent Finds of Islamic Coins from the Old Town and Zawodzie Districts in Kalisz

A settlement cluster around Kalisz first emerged in the Roman Period on a route leading from the south towards the Baltic coast. In the Early Middle Ages, a settlement centre connected with the Kalisz-Zawodzie stronghold developed at the crossroads of trade routes linking Wielkopolska with Silesia, Mazowsze, and Małopolska, with the earliest traces of early medieval occupation dating back to the 8th century. In the 10th century, oriental silver in the form of silver dirhams started to flow into the discussed region. These coins were part of deposits discovered in the sites of Kalisz-Szałe and Kalisz-Rajsków. Many years of research on artisanal settlement Kalisz-Stare Miasto produced a few fragments of Sāmānid dirhams minted between AH 279–343 (892–954). In 2018, during research at the Church of St. Adalbert located within the Kalisz-Zawodzie settlement accompanying the stronghold, a part of what was probably a larger silver deposit was found. In total, 13 dirham fragments were recovered, among which Sāmānid emissions dated to the first half of the 10th century were identified (8 pcs), as well as five pieces of undetermined dynastic attribution. As demonstrated by the stratigraphic analysis, the early medieval hoard had been discovered and dispersed at some point during the period when the church cemetery was used, between the 17th century and second half of the 18th century.

Correction: Complexing agent study via computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit

Correction for ‘Complexing agent study via computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit’ by Anmin Liu et al., RSC Adv., 2014, 4, 40930–40940, DOI: 10.1039/C4RA05869K.

Mineragenic Position and Geological Potential of Technogenic- Mineral Formations of the Gold-Silver Deposit Valunistoe (Сhukotka Autonomous Region)

In the coming years, the mine of LLC "Rudnik Valunisty" developing the gold and silver Valunistoe and Gornoye deposits will exhaust economically justified reserves. One of the ways to extend the life of the mine and increase the profitability of production should be the extraction of man-made secondary mineral resources. The purpose of the study is to identify the main types of solid and hydromineral form of technogenic-mineral formations at the Valunistoe Deposit, as well as to estimate the possibility of their industrial development. The useful components content was determined and calculated. The results of theoretical modeling of physical and chemical parameters of hypergenic mineral formation of the solid part of technogenic-mineral formations are shown. Objects of formation of technological waters are given. The conditions of concentration of gold and other metals are considered.

Age and Genesis of the Pokrovskoe Gold–Silver Deposit (Russian Far East)

––We present results of geochronological studies of rocks from different igneous complexes and of hydrothermally altered volcanics with Au–Ag mineralization from the Pokrovskoe deposit. The age of the ore-hosting granites of the Sergeevsky pluton of the Upper Amur complex is estimated at ~129 Ma. The primary age of dacites of a sill-like body is within 128–125 Ma and is close to the age of volcanics of the Taldan complex. Propylitization processes superposed on these dacites are dated at ~122–119 Ma. Taking into account the commercial contents of gold and silver in these rocks, we believe that the age of the hosted orebodies is in the same interval. The period 122–119 Ma is also the time of formation of the Gal’ka volcanic complex in the Umlekan volcanic zone, which was accompanied by granitoid magmatism. This suggests that the formation of the Pokrovskoe deposit was associated with the accumulation of the Gal’ka complex.

PECULIARITIES OF THE PYRITE CHEMICAL COMPOSITION IN THE SUPRA-ORE ZONE OF THE TASEEVSKOE GOLD-SILVER DEPOSIT (RUSSIA, TRANSBAIKALIA)

The relevance lies in the need to have objective data to assess the belonging of pyrite outcrops to the day surface to the supra-ore zones of gold deposits of a shallow gold-silver formation based on objective data on its chemical composition and forms of crystals and their aggregates. The purpose of the study is to determine the chemical composition of pyrite, the forms of its crystals and aggregates as typomorphic signs of their belonging to the supra-ore zone of the deposit of this formation. The object of the research is pyrite of the supra-ore zone of the Taseevskoye deposit, which is unique in terms of gold content and reserves. The subject of the research is the chemical composition and forms of pyrite separation. The method and methodology are presented by optical and electron microscopy with the determination of variations in the chemical composition of pyrite and morphological features of crystals and their aggregates. Results. The determination of the chemical composition of pyrite was carried out and it was found that almost all crystals are characterized by a sulfur deficiency, the formula coefficients of which are 1.801–1.939 with a change in content from 48.39 to 52.62 %. In 70 % of the measured pyrite crystals, arsenic is present from 0.72 to 4.78 % the formula coefficients of which are 0.007 - 0.076. In 2 % of pyrite crystals, along with As, antimony was found in an amount of 0.21 - 0.71 %, formula coefficients are 0.006 - 0.007. The forms of pyrite crystals are cubic, cubopentagondodecahedral, rarely cuboctahedral and subspherical aggregates, less often lenticular and veinlet, predominate. Conclusions. For the first time, original data on the chemical composition of pyrite in the supra-ore zone of the Taseevskoe gold-silver deposit were obtained. It is shown that its feature is high arsenic content (0.72 - 4.78 %), which can be an important typochemical sign for determining the belonging of chalcedony-like quartz containing it to the supra-ore zone of a shallow gold-silver formation

AGE OF EPITHERMAL GOLD-SILVER MINERALIZATION AT THE KUBAKA DEPOSIT (OMOLON CRATON TERRAIN, NORTHEAST OF RUSSIA): GEOLOGICAL AND ISOTOPE-GEOCHRONOLOGICAL (U-PB, 40AR / 39AR) LIMITATIONS

Geological, structural and mineralogical facts describing the intersection of Paleozoic ore veins with carbon and Mezozoic veins in the Kubaka gold-silver deposit in the Omolon craton terrane are presented. The totality of the above observations does not allow limitation of the age mineralization by Upper Carboniferous based on isotope-geological studies, as V.V.Akinin et al. (2020) did on ore and rock samples selected in one geological exposure of ore body in opencast mine of the Tsokolny zone.

On the genesis of the gold-silver deposit Kupol (North-East of Russia)

A new version of genesis of the epithermal gold-silver deposit Kupol (Chukotka), its mineral composition of ores and conditions of ore-localization based on the analysis of published geological materials on the geological structure had purposed in this article. The active thermal ore-forming role of completing the volcanic cycle of the multiphase subvolcanic complex’ the proximal bodies of the Upper Cretaceous rhyolites had been proved. The main factors of this deposit’ formation and the conditions that favored the appearance of large ore bodies and rich ores were considered. The magma chamber, unified faulty magmatic and fluid conductor, rock screen, flank clusters of subvolcanic rhyolite bodies and their integral thermal anomalies that initiated and sustained the deep fluid thermal convection under the screen, its mixing with fractured pore and meteoric waters and formation of gradient temperature zones, were considered among the main factors. The conjugation of these factors in space and time, the active tectonic regime and the long-term preservation of the deformation plan were the favorable conditions for ore formation. They maintained the high permeability of the fluid conductor, prevented a wide dispersion of fluids and provided a telescopic deposition of different mineral parageneses.

On the genesis of the gold-silver deposit Kupol (North-East of Russia)

A new version of genesis of the epithermal gold-silver deposit Kupol (Chukotka), its mineral composition of ores and conditions of ore-localization based on the analysis of published geological materials on the geological structure had purposed in this article. The active thermal ore-forming role of completing the volcanic cycle of the multiphase subvolcanic complex’ the proximal bodies of the Upper Cretaceous rhyolites had been proved. The main factors of this deposit’ formation and the conditions that favored the appearance of large ore bodies and rich ores were considered. The magma chamber, unified faulty magmatic and fluid conductor, rock screen, flank clusters of subvolcanic rhyolite bodies and their integral thermal anomalies that initiated and sustained the deep fluid thermal convection under the screen, its mixing with fractured pore and meteoric waters and formation of gradient temperature zones, were considered among the main factors. The conjugation of these factors in space and time, the active tectonic regime and the long-term preservation of the deformation plan were the favorable conditions for ore formation. They maintained the high permeability of the fluid conductor, prevented a wide dispersion of fluids and provided a telescopic deposition of different mineral parageneses.

Chapter 21: Geology of the Fruta del Norte Epithermal Gold-Silver Deposit, Ecuador

Fruta del Norte is a completely concealed and extremely well-preserved, Late Jurassic epithermal gold-silver deposit of both low- and intermediate-sulfidation type, which is located in the remote Subandean mountain ranges of southeastern Ecuador. Currently defined indicated resources are 23.8 million metric tons (Mt) averaging 9.61 g/t Au and the total endowment is 9.48 Moz Au. The deposit, notable for the widespread occurrence of visible gold and bonanza grades, will be bulk mined underground. Fruta del Norte was discovered in 2006 during greenfield exploration and systematic drill testing of a conceptual geologic model, which predicted that auriferous veins would occur in andesitic volcanic rocks inferred to underlie a zone of arsenic- and antimony-anomalous silicification in fluvial conglomerate. The host andesitic volcanic rocks, crosscutting feldspar porphyry, and associated phreatic breccia are part of a roof pendant in the Zamora batholith. Together, they are products of a continental-margin volcanoplutonic arc of Middle to Late Jurassic age. The deposit lies beneath the northern extremity of the ~16-km-long, Suárez pull-apart basin where it is localized by steep, second-order faults within the regionally extensive Las Peñas strike-slip fault zone. The pull-apart basin was progressively filled by fluvial conglomerate, dacitic ignimbrite, finer grained siliciclastic sedimentary rocks, and, finally, andesite flows. The Fruta del Norte deposit comprises a 1.3-km-long and up to >300-m-wide vein stockwork associated with quartz-illite-pyrite alteration. The deposit comprises two principal vein types, one in the south dominated by quartz, manganoan carbonates, and abundant base metal sulfides and the other in the north dominated by manganese- and base metal-poor quartz, chalcedony, and calcite. Adularia is a minor gangue mineral in both. Both vein types are abruptly transitional upward and westward to a third important ore type characterized by intense silicification and chalcedony veining, with disseminated and veinlet marcasite (± pyrite). An extensive silica sinter horizon directly overlies the andesitic rocks and/or occurs as interbeds in the lowermost 20 m of the conglomerate and, consequently, is in unusual proximity to the underlying gold-silver orebody. Much of the conglomerate lacks silicification except for a narrow, steeply inclined zone exposed above the deposit, which led to its discovery.