Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

Adakites are Y- and Yb-depleted, SiO2- and Sr-enriched rocks with elevated Sr/Y and La/Yb ratios originally thought to represent partial melts of subducted metabasalt, based on their association with the subduction of young (<25 Ma) and hot oceanic crust. Later, adakites were found in arc segments associated with oblique, slow and flat subduction, arc–transform intersections, collision zones and post-collisional extensional environments. New models of adakite petrogenesis include the melting of thickened and delaminated mafic lower crust, basalt underplating of the continental crust and high-pressure fractionation (amphibole ± garnet) of mantle-derived, hydrous mafic melts. In some cases, adakites are associated with Nb-enriched (10 ppm < Nb < 20 ppm) and high-Nb (Nb > 20 ppm) arc basalts in ancient and modern subduction zones (HNBs). Two types of HNBs are recognized on the basis of their geochemistry. Type I HNBs (Kamchatka, Honduras) share N-MORB-like isotopic and OIB-like trace element characteristics and most probably originate from adakite-contaminated mantle sources. Type II HNBs (Sulu arc, Jamaica) display high-field strength element enrichments in respect to island-arc basalts coupled with enriched, OIB-like isotopic signatures, suggesting derivation from asthenospheric mantle sources in arcs. Adakites and, to a lesser extent, HNBs are associated with Cu–Au porphyry and epithermal deposits in Cenozoic magmatic arcs (Kamchatka, Phlippines, Indonesia, Andean margin) and Paleozoic-Mesozoic (Central Asian and Tethyan) collisional orogens. This association is believed to be not just temporal and structural but also genetic due to the hydrous (common presence of amphibole and biotite), highly oxidized (>ΔFMQ > +2) and S-rich (anhydrite in modern Pinatubo and El Chichon adakite eruptions) nature of adakite magmas. Cretaceous adakites from the Stanovoy Suture Zone in Far East Russia contain Cu–Ag–Au and Cu–Zn–Mo–Ag alloys, native Au and Pt, cupriferous Ag in association witn barite and Ag-chloride. Stanovoy adakites also have systematically higher Au contents in comparison with volcanic arc magmas, suggesting that ore-forming hydrothermal fluids responsible for Cu–Au(Mo–Ag) porphyry and epithermal mineralization in upper crustal environments could have been exsolved from metal-saturated, H2O–S–Cl-rich adakite magmas. The interaction between depleted mantle peridotites and metal-rich adakites appears to be capable of producing (under a certain set of conditions) fertile sources for HNB melts connected with some epithermal Au (Porgera) and porphyry Cu–Au–Mo (Tibet, Iran) mineralized systems in modern and ancient subduction zones.

Key Models of Religious Institutions’ Interaction in the Context of the State-Church Relations in Russia and Egypt

The article reveals and comparatively analyses the peculiarities of the state-church relations in Russia and Egypt. Currently, the role of religion and religious institutions in world politics is actively increasing, as well as the process of secularization of public life is being redefined. Religion still often becomes the cause of discrimination, persecution of certain groups of society; the level of Islamophobia in Western countries and Religiophobia in the whole world is not decreasing. In these conditions, the importance of state-church relations within key international actors is also growing. The purpose of the study is to provide comparative analysis of the specifics of the state religion policy of Russia and Egypt in order to develop recommendations for the use of Russian religious institutions to strengthen Russias position in the Middle East. Russia and Egypt were chosen as research objects, since these countries have a rich history of interaction in the religious sphere, which could become a basis for the future cooperation between religious institutions of the two countries. In addition, Egypt is one of the key states in the Middle East, where Russian influence has never been dominant, but where exactly religious organizations such as the Russian Orthodox Church (ROC) most actively and successfully pursued Russias interests. Methodologically, the article is based on historical and empirical institutionalism, as well as comparative analysis and historical-genetic method. The study is quite novel, as it identifies four models of interaction between religious communities, which are based on two criteria: a) presence of religious institutions representing the interests of a particular community; b) status of religion in the state (dominant / minority religion). The practical significance of the study lies in its attempt to make recommendations for improving the use of religious organizations in Russia to promote state interests in Egypt on the basis of the highlighted features of state-church relations in Egypt.

Impact of fires on eutrophication in rivers (the Simmy River, the Bolon Nature Reserve)

Compared to research on eutrophication in lakes, our understanding of eutrophication in rivers remains extremely limited. This is especially true of the impact of fires, which have become much more frequent in recent decades. Since the risks of eutrophication in rivers as a result of fires increase, it is important to timely assess the impact of fires on the state of rivers draining fire-prone territories. The aim of the study is to select and evaluate the reliability of criteria for impact of fires on eutrophication in stream on the example of the Simmi River (Bolon Nature Reserve, Far East, Russia). The tasks of the work are to assess the fire-prone of the territory from remote sensing data and and to identify markers of the impact of fires on the Simmi River. The fire-prone of the river watershed was estimated by the fire repeatability. The in situ study dealt with river bottom sediments. The sampling was carried out in in three month and the third year after the fire. To assess the impact of fires on eutrophication in the Simmi River, we used the P content in bottom sediments as a marker of the nutrient loading. The obtained results indicate high fire-prone and repeatability of fires the river watershed. In the first months after the fire, the response of the river system is the sequestration of P soluble compounds as a result of the binding of phosphate ions to vivianite. Vivianite is formed on the surface of clay microaggregates, which are removed by the stream over time. In three years after fire, vivianite-clay microaggregates were not detected. Flushing in flow system tends to reduce the scale of the fire impact.

Natural and anthropogenic risks after a giant landslide in the Russian Far East

At the Bureiskoe Reservoir (Far East, Russia) in December 2018 at a temperature of 36°C below zero the giant landslide is occurred. Landslide with a total volume of 24.5 million m3 blocked the reservoir from one shore to the opposite one, disrupting the access of water to a large hydroelectric power station downstream. Blasting operations were carried out with the use of trinitrotoluene and hexogen to revive the water flow. As a result of the landslide natural hazards (direct impact of the landslide, and tsunami) were happened, and the further strong impact was caused by humans (blasting). Volatile organic compounds (VOCs) and elemental composition were accepted as the main indicators of water quality. Parameters of these indicators varied at different near-shore sites above and below the landslide area. More significant changes are recorded after blasting operations. Hexane and toluene dominated the water passing the artificial channel. The genesis of VOCs can be associated with the biogeochemical processes of methanogenesis, methanotrophy, and the detonation products of explosives. Mercury, methanol, toluene, and xylenes in water samples were detected. This is evidence of the presence of a prerequisite for the formation of toxic methylmercury, a risk factor for aquatic biota.

Dangerous Gifts

From Napoleon Bonaparte’s invasion of Egypt in 1798 to the foreign interventions in the ongoing civil wars in Syria, Yemen, and Libya today, global empires or the so-called Great Powers have long assumed the responsibility of bringing security to the Middle East. The past two centuries have witnessed their numerous military occupations to ‘liberate’, ‘secure’, and ‘educate’ local populations. Consulting fresh primary sources collected from some thirty archives in the Middle East, Russia, the United States, and Western Europe, Dangerous Gifts revisits the late eighteenth- and nineteenth-century origins of these imperial security practices. It questions how it all began. Why did Great Power interventions in the Ottoman Levant tend to result in further turmoil and civil wars? Why has the region been embroiled in a paradox—an ever-increasing demand for security despite the increasing supply—ever since? It embeds this highly pertinent genealogical history into an innovative and captivating narrative around the Eastern Question, freeing the latter from the monopoly of Great Power politics, and also foregrounding the experience and agency of the Levantine actors: the gradual yet still forceful opening up of the latter’s economies to global free trade, the asymmetrical implementation of international law from their perspective, and the secondary importance attached to their threat perceptions in a world where political and economic decisions were ultimately made through the filter of global imperial interests.