Accessing effects and signals of leakage from a CO<Subscript>2</Subscript> reservoir to a shallow freshwater aquifer by reactive transport modelling

CO₂ geological storage is a transitional technology for the mitigation of climate change. In the vicinity of potential CO₂ reservoirs in Hungary, protected freshwater aquifers used for drinking water supplies exist. Effects of disaster events of CO₂ escape and brine displacement to one of these aquifers have been studied by kinetic 1D reactive transport modelling in PHREEQC. Besides verifying that ion concentrations in the freshwater may increase up to drinking water limit values in both scenarios (CO₂ or brine leakage), total porosity of the rock is estimated. Pore volume is expected to increase at the entry point of CO₂ and to decrease at further distances, whereas it shows minor increase along the flow path for the effect of brine inflow. Additionally, electrical conductivity of water is estimated and suggested to be the best parameter to measure for cost-effective monitoring of both worst-case leakage scenarios.     

Variation in style of magmatism and emplacement mechanism induced by changes in basin environments and stress fields (Pannonian Basin,Central Europe)

The development of high‐resolution 3D seismic cubes has permitted recognition of variable subvolcanic features mostly located in passive continental margins. Our study area is situated in a different tectonic setting, in the extensional Pannonian Basin system (central Europe) where the lithospheric extension was associated with a wide variety of magmatic suites during the Miocene. Our primary objective is to map the buried magmatic bodies, to better understand the temporal and spatial variation in the style of magmatism and emplacement mechanism within the first order Mid‐Hungarian Fault Zone (MHFZ) along which the substantial Miocene displacement took place. The combination of seismic, borehole and log data interpretation enabled us to delineate various previously unknown subvolcanic‐volcanic features. In addition, a new approach of neural network analysis on log data was applied to detect and quantitatively characterise hydrothermal mounds that are hard to interpret solely from seismic data. The volcanic activity started in the Middle Miocene and induced the development of extrusive volcanic mounds south of the NE‐SW trending, continuous strike‐slip fault zone (Hajdú Fault Zone). In the earliest Late Miocene (11.6–9.78 Ma), the style of magmatic activity changed resulting in emplacement of intrusions and development of hydrothermal mounds. Sill emplacement occurred from south‐east to north‐west based on primary flow‐emplacement structures. The time of sill emplacement and the development of hydrothermal mounds can be bracketed by onlapped forced folds and mounds. This time coincided with the acceleration of sedimentation producing poorly consolidated, water‐saturated sediments preventing magma from flowing to the paleosurface. The change in extensional direction resulted in change in fault pattern, thus the formerly continuous basin‐bounding strike‐slip fault became segmented which could facilitate the magma flow toward the basin centre.     

Monopole abundance from first-order GUT phase transition of the early Universe

Monopole annihilation and pair creation are investigated in a first order GUT symmetry breaking phase transition without inflation. It is found that even with complete initial monopole suppression, some monopoles are inevitably produced during the transition. According to this, some constraints are obtained for initial and equilibrium monopole densities in order to be compatible with the present observational limits even without inflation.     

Problems of the „Pannonian Median Massif“ and the plate tectonic concept. Contributions based on the distribution of Late Paleozoic — Early Mesozoic isopic zones

After a short historical review of conceptions about the Pannonian Median Massif or Tisia, the distribution of Middle-Upper Carboniferous and Lower Triassic-Liassic facies is briefly examined on the two sides of the Zagreb-Zemplin line dividing into two main segments the basement of the Carpathian basin. It shows on the one hand, that the Igal-Bükk zone (Igal-Bükk eugeosyncline ofWein, 1969), thought to establish a connection between the NW-Dinarides and the Dinaric-type Bükkium, is only a tectonic zone and could never have been a paleogeographical unit. On the other hand, the northern, marginal part of Tisia (Mecsek-Bihor crystalline belt and its sedimentary cover;Dank &Bodzay, 1971) exhibits a development and facies characteristic of the northern (northeastern) marginal complex of the Tethys. Also, facies-transitions from the foreland toward the open sea are always of N S direction. All autochthonous explanations must face the striking differences along the Zagreb-Zemplin line, which seem to exclude the possibility that the northern part of Tisia was a central, partly emerged crystalline ridge (no facies-transitions toward N!); it was rather part of the northern (northeastern) marginal complex of Tethys. Therefore allochthonous models suggesting largerscale horizontal movements give a much more plausible explanation. The style of Late Hercynian development and the distribution of Lower Triassic-Liassic facies zones suggest, that Tisia was part of the northern (northeastern) shelf of the Tethys until the end of the Liassic (in accordance with the opinion ofBleahu), then split off and was wedged in by horizontal movements between the NW-Dinarides and the Dinaric-type Bükkium by the end of the Jurassic — beginning of the Cretaceous.

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Zusammenfassung Nach einem kurzgefaßten historischen Überblick zur Deutung des Pannonischen Massivs oder Tisia wird die Verteilung der Fazies von Mittel- und Oberkarbon sowie Untertrias bis Lias auf den beiden Seiten der Zagreb-Zemplin-Linie — welche den Untergrund des Karpatenbeckens in zwei Abschnitte zerteilt — kurz untersucht. Sie zeigt einerseits, daß die Igal-Bükk-Zone (die Igal-Bükk Eugeosynklinal vonWein, 1969)-welche eine Verbindung zwischen den NW Dinariden und dem dinarisch-typischen Bükkium darstellen soll — nur eine tektonische Zone ist, hingegen nie eine paleogeographische Einheit gewesen sein kann.Der nördliche, äußerste Teil des Tisia (Mecsek-Bihor kristalliner Gürtel und seine sedimentäre Decke;Dank u.Bodzay, 1971) weist eine Ausbildung und Fazies auf, welche für den nördlichen (nordöstlichen) marginalen Komplex der Tethys typisch ist. Auch Faziesübergänge vom Vorland in der Richtung der offenen See sind immer N S gerichtet. Alle Erklärungen, die eine autochthone Lage der Zonen entlang der Zagreb-Zemplin-Linie mit einbeziehen, müssen mit der Tatsache fertig werden, daß der nördliche Teil der Tisia einen zentralen Teil eines teilweise emporgehobenen Kristallinrückens darstellt (kein Faziesübergang nach Norden). Sie war eher Teil der nördlichen (nordöstlichen) marginalen Serie der Tethys. Daher erscheinen allochthone Modelle, welche horizontale Bewegungen in größerem Maßstabe andeuten, eher glaubwürdig zu sein. Der Stil der spätherzynischen Entwicklung und die Verteilung der Fazieszonen von Untertrias bis Lias deuten an, daß der Tisia Teil der nördlichen (nordöstliche) Shelf der Tethys bis Ende Lias war (übereinstimmend mit der Meinung vonBleahu 1976); dann spaltete er sich ab und keilte sich mit horizontalen Bewegungen zwischen den NW Dinariden und dem Bükkium dinarischen Types ein; dies könnte Ende Jura-Anfang Kreide stattgefunden haben.

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Résumé Après une brève revue historique des conceptions sur la »Masse médiane pannonienne« ou la »Tisia«, on examine brièvement la distribution des facies du Carbonifère moyen-supérieur et du Trias-Lias aux deux cotés de la ligne de Zagreb-Zemplin divisant le soubassement du Bassin Carpathique en deux ségments principaux.Ce qui est démontré, c'est d'une part que la zone Igal-Bükk (le »géosynclinal Igal-Bükk«, Wein, 1969), considérée comme l'établissement d'une communication entre les Dinarides du NW et le Bükkium de type dinarique, ne représente qu'une zone tectonique, mais qu'elle ne peut jamais être une unité paléogéographique. D'autre part la partie septentrionale, marginale de la »Tisia« (la ceinture crystalline de» Mecsek-Bihor« et sa couverture sédimentaire; Dank-Bodzay, 1971) présente un développement et un faciès caractéristique du complexe marginal septentrional (nordoriental) de la Téthys. Les transitions de faciès de l'avant-pays vers la mer ouverte sont également de direction N-S. Toutes les explications autochtonistes doivent faire face aux différences accentuées le long de la ligne Zagreb-Zemplin, ce qui semble exclure la possibilité que le Nord de la »Tisia« ait été une dorsale cristalline centrale, émergée (aucune transition de faciès vers le N!); elle a fait plutôt partie du complexe marginal du N (NE) de la Téthys. C'est pourquoi les modèles allochtonistes suggérant des mouvements horizontaux plus vastes donnent une explication plus plausible. Le style du développement éohercynien et la distribution des zones faciales du Trias inférieur-Lias suggèrent que la »Tisia« a fait partie du shelf septentrional (nordoriental) de la Téthys jusqu'à la fin du Lias (en accord complet avec l'opinion de Bleahu, 1976) et qu'ensuite elle s'était décollée et coinné par des mouvements horizontaux entre les Dinarides du NW et le Bükkium de type dinarique vers la fin du Jurassique et le début du Crétacé.

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Because of shortage of place, only some of the most important non-Hungarian literature and the latest Hungarian works concerned with this region are listed up here: for a more detailed list of reference the reader is referred to the papers ofBalogh (1972) andKovács (1980).     

Interplay of tectonics and neogene post-collisional magmatism in the intracarpathian region

Distribution of the Neogene calc-alkaline magmatism of the Carpathian arc is directly related in space and time to the kinematics of the two major terranes of the Intracarpathian area (Alcapa, Tisia-Getia) along the south-eastern border of the European plate. In the West Carpathians and adjacent areas, the volcanic activity occurred between 20–11 Ma, with large volumes of both acidic and intermediate rocks, generally distributed randomly, sometimes transversally to the orogenic belt and as rare small occurrences along the Flysch belt. In the East Carpathians, the volcanic rocks are distributed along the northern margin of the Zemplin block, the north–easternmost part of the Alcapa and eastward along the front of the Getic block, at the contact with European plate. Between Tokaj-Slanské-Vihorlat up to northern Cãlimani Mountains, the magmatism occurred between 14–9 Ma, and along the Cãlimani-Harghita chain between 9–0.2 Ma. The calc-alkaline magmatic rocks of the Apuseni Mountains are located in the interior of the Tisia block and occurred between 14–9 Ma. The generation of the calc-alkaline magmatism is considered here as the result of complex interplay between plate roll-back and lithospheric detachment tectonic processes and the break-off of the subducted plate, mostly in a post-collisional setting. (1) The magmatites of the Western Carpathians and the Pannonian basin were generated in direct relation to subduction roll-back processes, over the downgoing slab, during the period of lateral extrusion and back-arc extension. In this area, characterized by maximum crustal shortening, we can infer further delamination processes to explain the generation of magmas. (2) The magmatic rocks from the northern sector of the East Carpathians (Tokaj-Slanské-Vihorlat up to the Northern Cãlimani Mountains), resulted after subduction roll-back processes and an almost simultaneous break-off of the descending plate all along the arc segment during main clockwise rotation of the Intracarpathian terranes. (3) In the eastern sector of the East Carpathians (Cãlimani up to Harghita Mountains), the magmatic rocks were generated through partial melting of the subducted slab followed by gradual break-off of the subducted plate along strike (north to south). (4) The Apuseni Mts. magmatic activity resulted in transtensional tectonic regime by decompressional melting of lithospheric mantle, during the translation and rotation of Tisia-Getia block.