Virtual special volumes
These "Virtual Volumes" are collections of topical papers with similar focus published in the Journal of Geosciences over the years. The papers are hand-picked by responsible editors; the real thematic sets of papers which have appeared as a single issue are also indicated.
Structural, petrological and geochemical studies of granulites, felsic gneisses, eclogites, garnet... peridotites and skarns, including constraints on P–T conditions and evolution of the rocks, radiogenic isotopes and geochronological dating, and seismic anisotropy, provide evidence for high-pressure and ultra-high pressure metamorphism, high-pressure melting and crust-mantle interactions and allow to resolve deep crustal and upper mantle structure and processes in the internal zones of the Central European Variscides, such as Moldanubian Zone or Kutná hora Crystalline Complex of the Bohemian Massif.
Many issues regarding the compositional variability, possible sources and significance of... individual processes (partial melting, fractional crystallization, assimilation, and/or magma mixing) in generation of subduction-related, syn- and post-tectonic granitic suites remain hotly debated. Apart from such often geochemistry-oriented studies, structural research may constrain pluton emplacement mechanisms, and thus the overall geodynamic context. The papers mostly focusing on Variscan plutons in Europe (Spain, France, Slovakia, Bohemian Massif) or elsewhere (Mongolia) often provide useful, process-oriented case studies with a broad outreach.
Various highly evolved felsic igneous systems and granitic pegmatites in particular represent the... most evolved products of geochemical fractionation and textural differentiation in the Earth crust. We draw attention to all aspects of the mineralogy, geochemistry, petrology, isotope systematics and industrial significance of these systems, and provide a forum for the discussion of their petrogenesis, tectonic environment, genetic links to parental granites and evolution from magmatic to hydrothermal stage, as well as unique crystal chemistry of relevant accessory minerals.
Distribution of mineral deposits in various geotectonic s settings and mineralization epochs.... Metallogeny of the Bohemian massif and of the Western Carpathians. Classification of the types of mineral deposits. Occurrences and structures of mineral deposits in different lithologies, position of mineral deposits in the host rocks ,sequences of formation of mineral assemblages, genetic /spatial relation to specific intrusive rocks. Studies of physico-chemical processes leading to the origin of mineral deposits. Geochemical methods used in revealing the genesis and nature of ore minerals and mineral deposits. Significance of ore minerals. Studies of chemical compositions, mechanism of chemical substitutions and crystal structures of ore minerals.
Studies of chemical composition, compositional variations, evolutionary trends, textural and... paragenetic relations of rock-forming and accessory minerals. The papers dealing with accessory minerals contribute mainly to the crystal chemistry and various genetic aspects of niobium–tantalum oxide minerals, niobian rutile, zircon, thorite and tourmaline. Significance of mineral chemistry of clinopyroxene as a record of the crystallization processes of basaltic magma is demonstrated. The geochemical evolution of granite–pegmatite systems is documented by chemical composition of micas.
Mineralogy of supergene phases plays a crucial role for the knowledge of mobility and transport of... environmentally important elements, contamination and subsequent remediation. It also contributes to the fundamentals of crystallography, crystal-chemical principles, or genesis of ore deposits.
Among the geophysical methods studying deep structure of the crust and mantle lithosphere of the... Bohemian Massif (BM) are airborne magnetic and gamma-ray spectrometric as well as ground gravity survey, seismic refraction profiling, teleseismic tomography and investigation of seismic anisotropy. The gravity surveys contributed to a better knowledge of several granitic plutons, the characteristic phenomena of the BM. The seismological studies focused mainly on the deep structure of the Ohře (Eger) Graben, a prominent tectonic feature known by its abundant Cenozoic volcanism and a present-day geodynamic activity in its western part.
Tectonic evolution of the Bohemian Massif is a key issue in understanding the formation of the... Variscan orogenic belt in Europe. The Bohemian Massif apparently exposes the whole orogenic structure including two colliding Neoproterozoic crustal blocks, well documented relics of Devonian–Carboniferous subduction zone in-between, relatively weakly deformed fore-arc region, deeply eroded magmatic arc and a former back-arc domain that was deeply buried and strongly reworked during collisional stage of the orogeny. This virtual volume brings together those contributions related directly to Palaeozoic magmatic, metamorphic and tectonic processes in particular orogenic domains that led to the establishment of the present-day Bohemian Massif structure.
Post-Variscan evolution of the Bohemian Massif has been repeatedly associated with continental... within-plate volcanism. The decay of Variscan orogen resulted in formation of intermontane basins, where both mafic and silicic volcanism occurred frequently. Doming of asthenospheric mantle since the Latest Cretaceous resulted in formation of alkaline magmas. The Cenozoic alkaline volcanic activity concentrated in the Eger Graben (e.g., Doupovské hory Volcanic Complex, České středohoří Volcanic Complex), but occurred also on the rift shoulders up to 150 km off its axis.
Students of the Variscan Belt of Europe frequently note incomplete if not fragmental state of... preservation of this orogenic belt. Numerous segments of the Variscan crust were uplifted to the surface in the Western Carpathians and reveal some of the seemingly missing pieces of information. Additional bonus of this segment of the Alpine-Carpathian domain are the imprints of the Alpine age processes.
Endless steppe, rugged mountains and deserts of Mongolia hide away great mineral potential and... glamorous geological phenomena which attract geologists from all over the world to discover them. Papers presented in the Journal of Geosciences focus on the areas in the SW Mongolia, most of all in the remote Trans-Altay Gobi and junction of the Mongolian and Gobi Altay mountains ranges. Majority of papers describe geology, geochemistry and age of the Palaeozoic plutonic bodies, PT conditions of newly recognized metamorphic complexes are also mentioned. The Mesozoic volcanic activity related to the Gobi Altay rift evolution is documented by isotopic data. Geophysical cross-section revealed internal structure of the intra-continental Bogd fault system, exceptional is discovery of mud spots related to seismic activity on this fault. Location of palaeoplacers with up to cm large gold nuggets confirmed the dry stream-sediments geochemistry to be a suitable method for regional prospection in arid areas of Mongolia.
Subduction-related magmatism in the today’s Central America has taken place upon various plate... configurations since Mesozoic. Wide range of magma types, source compositions, eruptive styles and eruption ages together with good accessibility and urgency of hazard mitigation make the area focus point of enduring international research effort.