Fluid evolution in the Baia Mare epithermal gold/polymetallic district, Inner Carpathians, Romania (original) (raw)
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Ore Geology Reviews, 2005
The Inner Carpathians comprise several distinct Neogene late-stage orogenic Pb-Zn-Cu-Ag-Au ore districts. The mineral deposits in these districts are closely related to volcanic and subvolcanic rocks, and represent mainly porphyry and epithermal vein deposits, which formed within short periods of time in each district. Here, we discuss possible geodynamic and structural controls that suggest why some of the Neogene volcanic districts within the Carpathians comprise abundant mineralization, while others are barren. The Neogene period has been characterized by an overall geodynamic regime of subduction, where primary roll-back of the subducted slab and secondary phenomena, like slab break-off and the development of slab windows, could have contributed to the evolution, location and type of volcanic activity. Structural features developing in the overlying lithosphere and visible in the Carpathian crust, such as transtensional wrench corridors, block rotation and relay structures due to extrusion tectonics, have probably acted in focusing hydrothermal activity. As a result of particular events in the geodynamic evolution and the development of specific structural features, mineralization formed during fluid channelling within transtensional wrench settings and during periods of extension related to block rotation.
Carpathian Balkan Geological Association
etamorphism of the Central Western Carpathians is given in the excursion guide. The manuscript of this work was improved by helpful suggestions of S. Jacko, D. Plaienka and M. Jank. This work was supported by Slovak Academic Agency, project WEGA-#/5003/98 ################# #50 Contents #. Outline on structure and metamorphism of the Western Carpathians #5# #.# External Western Carpathians #52 #.2 Central Western Carpathians #52 #.2.# Pieniny Klippen Belt #52 #.2.2 The Tatra-Fatra Belt #53 #.2.2.#. Pre-Alpine metamorphism in the Tatra-Fatra Belt #53 #.2.2.2. Alpine metamorphism in the Tatra-Fatra Belt #55 #.2.3 The Vepor Belt #55 #.2.3.#. Pre-Alpine metamorphism in the Vepor Belt #56 #.2.3.2. Alpine metamorphism in the Vepor Belt #59 #.2.4. The Gemer Belt #60 #.2.4.#. Pre-Alpine metamorphism in the Gemer Belt #60 #.2.4.2 Alpine metamorphism in the Gemer Belt #62 #.3 Inner Western Carpathians #62 2. References #64 3. Description of Loc
Mineralia Slovaca, 2016
The review, based on binomial division of the Western Carpathians into Inner (Internal) and Outer (External) ones, provides a chronological description of Paleozoic and Cenozoic multiple riftogenesis, subduction/ collision and post-collision evolution with their metallogenetic consequences, in earlier classifications designated as Paleo-, Meso-and Neo-Variscan/Hercynian, as well as Paleo-, Meso-and Neo-Alpine phases. The introductory remarks form the base on which new tectonometamorphic and metallogenetic re-interpretations are grounded. In the geological setting of the Inner Western Carpathians, the Cretaceous Paleo-Alpine crustal tectonic units (Tatric, Veporic, Gemeric and Zemplinic units) are the most conspicuous, the first three being covered by superficial nappes (Fatric, Hronic, Meliatic, Turnaic and Silicic units). Earlier, Variscan (Hercynian) basement units encompass the Paleozoic and older crystalline basement and its Paleozoic and Mesozoic cover. The remnants of the Cenozoic Meso-Alpine units crop out only at the boundary of the Outer and Inner Western Carpathians and are influenced by dominating Cenozoic-Quaternary Neo-Alpine overprint. Four principal metallogenetic periods in the Western Carpathians are defined in the paper. A principal role in geodynamic processes as well as metallogeny of the Western Carpathians is attributed to linear source of convection heat of equatorial direction (mantle plume; hot line s.l.) acting under this orogenic belt from the Early Paleozoic until Cenozoic. During this extended period, the linear heat source has caused a multiple divergence within the Pangea (Gondwana/Laurasia) and its metallogenetic consequences-stratabound and magmatogenic mineralization during the divergent origin of elongated basins, as well as metamorphic/magmatogenic mineralization after their convergent closure by the lithospheric plates/microplates collision. The first metallogenetic period is related to Early Paleozoic pre-and riftogeneous phases (Cambrian to Ordovician, and/or Devonian to Early Carboniferous), the second Late Paleozoic one is a consequence of Permian overheating during the Variscan post-collisional evolution, including regional extension, magmatic and metallogenetic processes, the third one is a product of Late Cretaceous overheating due to the Paleo-Alpine post-collisional phase, and the fourth one-the Neo-Alpine metallogenetic phase is a consequence of Miocene overheating and the magmatic/volcanic processes related with the heat from the asthenosphere upwelling. The review encompasses also a brief summary of produced mineralization types.
Tectonophysics, 2005
The Carpathians-Pannonian Basin system provides a natural laboratory for analysing lithospheric to surface controls on tectonic topography development in a coupled source-to-sink environment. To link processes taking place at depth and at the surface, recent research focused on the interplay between basin evolution, active tectonics, topography evolution and intraplate folding mechanisms. Neotectonic processes control landscape development and natural hazards, in particular the seismicity, during the late-stage (Late Neogene-Quaternary) evolution of both the Carpathians-Pannonian Basin system and its interaction with the adjacent Dinarides and Balkans. The deep structure of the SE Carpathians exerts a strong control on the post-collisional evolution of the system. New constraints are available from seismic tomography, deep seismic reflection and refraction profiling and detailed studies of the Vreancea seismicity. Inherited orogenic fabric and structure of the active Black Sea sink has a strong influence on the localisation of the Neogene sediment pathways. A close relationship has been established between the timing and mechanisms of stress changes in the Pannonian and Transylvania basins and structural episodes in the surrounding thrust belts, pointing to an intrinsic mechanical coupling with these basins, the orogen and its foredeep. Basin inversion taking place during the Pliocene-Quaternary times in the entire Carpathians-Pannonian system is related to changes in the regional stress field leading to differential vertical movements associated with a laterally variable folding mechanism active in the entire system. Short, crustal folding patterns alternate with lithospheric wavelengths in the SE Carpathians foreland, East and South Carpathians, Transylvania and Pannonian basins. The lateral variability is the result of a marked contrast in rheology between these areas, directly related to the crustal configuration, thermal properties and late-stage collision kinematics with the Carpathians foreland. Lateral variations in the properties of the downgoing plates largely control the collision mode in the Carpathians and the post-collisional evolution of the entire system. D
Global and Planetary Change, 2016
The data about the Paleogene basin evolution, palaeogeography, and geodynamics of the Western Carpathian and Northern Pannonian domains are summarized, re-evaluated, supplemented, and newly interpreted. The presented concept is illustrated by a series of palinspastic and palaeotopographic maps. The Paleogene development of external Carpathian zones reflects gradual subduction of several oceanic realms (Vahic, Iňačovce-Kričevo, Szolnok, Magura, and Silesian-Krosno) and growth of the orogenic accretionary wedge (Pieniny Klippen Belt, Iňačovce-Kričevo Unit, Szolnok Belt, and Outer Carpathian Flysch Belt). Evolution of the Central Western Carpathians is characterized by the Paleocene-Early Eocene opening of several wedge-top basins at the accretionary wedge tip, controlled by changing compressional, strike-slip, and extensional tectonic regimes. During the Lutetian, the diverging translations of the northward moving Eastern Alpine and northeast to eastward shifted Western Carpathian segment generated crustal stretching at the Alpine-Carpathian junction with foundation of relatively deep basins. These basins enabled a marine connection between the Magura oceanic realm and the Northern Pannonian domain, and later also with the Dinaridic foredeep. Afterwards, the Late Eocene compression brought about uplift and exhumation of the basement complexes at the Alpine-Carpathian junction. Simultaneously, the eastern margin of the stretched Central Western Carpathians underwent disintegration, followed by opening of a fore-arc basinthe Central Carpathian Paleogene Basin. In the Northern Hungarian Paleogene retro-arc basin, turbidites covered a carbonate platform in the
Studia Universitatis Babes-Bolyai, Geologia, 2003
The Transylvanides which represent the uppermost group of Alpine tectonic units of the Apuseni Mountains originated from a Mesozoic rift located between the Preapulian and Getic cratons (Rădulescu & Săndulescu, 1973; Săndulescu, 1984; Balintoni, 1997). The term "Foreapulian Block" ("Preapulian bloc" in Romanian translation), was used by Săndulescu (1994), for the continental mass from which the Northern Apusenides or Inner Dacides (the Codru and Biharia Nappe Systems) have been sheared. The name "Getic Craton" was proposed by Balintoni (1994a) for the continental fragment located between the Transylvanian Rift and the External Carpathian Flysch Basin, from which proceeded the Getic crystalline. The Transylvanides were emplaced antithetically, during the Austrian and Laramian orogenic phases. During the compressional (Early Cretaceous) period, the rift basin evolved towards a foreland retroarc type basin, because it was installed on the upper plate sheared margin. If the Austrian Transylvanides (ATS) and the Mediterranean Apusenides are described as "in-sequence" tectonic units, the Laramian Transylvanides (LTS) are "out of sequence". In the Apuseni Mountains tectonic context, the Austrian orogenic phase is considered intra-Albian or around the Aptian-Albian boundary, the Mediterranean one as intra-Turonian (pre-Gosau) and the Laramian one as intra-Maastrichtian and close to the Maastrichtian end. This fact complicates the recognition of the Transylvanides, as well as their description and classification. Balintoni (1994, 1997) proposed a dual classification of the Transylvanides, with particular names for the Austrian and Laramian ones, because some parts of the ATS can be found again within several units of the LTS. According to latter classification of this author, the ATS include the Izvoarele, Valea Muntelui, Feneş, Colţul Trascăului, Bedeleu, Ardeu, Căbeşti, Căpâlnaş-Techereu and Bejan nappes, and the LTS comprise the Groşi, Crilş-Bucium, Vulcan, Frasin, Metalliferous Mountains, Curechiu-Stănija and Mureş nappes. Besides this, the Laramian Transylvanides transported also the post-Austrian sedimentary covers. Regarding the ATS and LTS many unsolved questions still persist, as it is for instance: the precise age for pre-Austrian and post-Austrian sedimentary formations; the correlation between the Austrian tectonic units enclosed by the Laramian nappes; the number of the LTS; the amplitude of the tectonic displacement; the relation between the Apuseni Mountains and the South Carpathians; the opening age of the Transylvanian Rift; the development of the magmatic component of the Transylvanides; the initial locale for the sedimentary and magmatic formations. In the following we will analyse some actual issues of the relation between the ATS and the LTS and present an improved model. I. The Bucium Unit: fact or myth? The Bucium Unit was first described by Ianovici et al. (1976) as a part of the South Apuseni Mountains. These authors considered the South Apuseni Mountains as built up of some Early Cretaceous facial-structural units, arranged later by tectonic thrusting and folding, and they mentioned in the lowermost position, the Bucium Unit. According to them, the Early Cretaceous formations of the Bucium Unit are transgressively deposited upon the crystalline schists of the Highiş rise, which is formed by the Baia de Arieş and Muncel tectonic units. They are consisting of: micritic limestones, Tithonian-Neocomian in age; the Căbeşti Beds, Hauterivian-Aptian; the Valea Dosului Beds, Aptian; the Ponor Beds, Albian and the Pârâul Izvorului Beds, Late Albian-Cenomanian. In their upper part, the Pârâul Izvorului Beds grade into the Cenomanian Negrileasa conglomerates. The Pârâul Izvorului Beds unconformably overly the earlier formations, due to the Austrian orogenic movements. Bleahu et al. (1981) confirm that the sedimentary deposits of the Bucium Unit constitute the cover of the Baia de Arieş and Muncel nappes, yet they partially modify the lithostratigraphy of these deposits. Lupu (1983) considers the Bucium Unit as autochthonous, tectonically in a similar position as outlined by Bleahu et al. (1981).
International Journal of Earth Sciences, 2012
A study has been performed on the Cretaceous to Early Miocene succession of the Vrancea Nappe (Outer Carpathians, Romania), based on field reconstruction of the stratigraphic record, mineralogical-petrographic and geochemical analyses. Extra-basinal clastic supply and intrabasinal autochthonous deposits have been differentiated, appearing laterally inter-fingered and/or interbedded. The main clastic petrofacies consist of calcarenites, sub-litharenites, quartzarenites, sub-arkoses, and polygenic conglomerates derived from extra-basinal margins. An alternate internal and external provenance of the different supplies is the result of the paleogeographic re-organization of the basin/margins system due to tectonic activation and exhumation of rising areas. The intra-basinal deposits consist of black shales and siliceous sediments (silexites and cherty beds), evidencing major environmental changes in the Moldavidian Basin. Organic-matter-rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting. The black shales display relatively high contents in sub-mature to mature, Type II lipidic organic matter (good oil and gas-prone source rocks) constituting a potentially active petroleum system. The intra-basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the Oligocene part of the succession can be correlated with volcanic supplies. The integration of all the data in the ''progressive reorientation of convergence direction'' Carpathian model, and their consideration in the framework of a foreland basin, led to propose some constrains on the paleogeographic-geodynamic evolutionary model of the Moldavidian Basin from the Late Cretaceous to the Burdigalian.