Mirka Trajanova

Geological Survey of Slovenia

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Bogomir Jelen

Geological Survey of Slovenia

László Fodor

Eötvös Loránd University

Miloš Bavec

Geological Survey of Slovenia

Marko Vrabec

University of Ljubljana

AŠ

Andrej Šmuc

University of Ljubljana

István Dunkl

University of Göttingen

Zoltán Pécskay

Massey University

Nina Zupančič

University of Ljubljana

Emő Márton

Eötvös Loránd University

Balázs Koroknai

Geomechanica (Canada)

Cooperative Institutions

Geological Survey of Slovenia

University of Ljubljana

Eötvös Loránd University

Institute for Geological and Geochemical Research

Hungarian Academy of Sciences

Croatian Geological Survey

Karst Research Institute

ETH Zurich

Ivan Rakovec Institute of Palaeontology

Institute for the Protection of Cultural Heritage of Slovenia

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The karren peeling off on marbles in Altai (Altai Republic, Russian Federation)

Acta Carsologica (2020)

Martin Knez Tadej Slabe Mirka Trajanova Tatiana Akimova Igor Kalmiykov

A comparison of karren formation on various rocks under diverse environmental conditions makes an important contribution to our understanding of the formation and development of karst. In this regard, the present study brings a number of new insights through description of the karst development on marbles at the foothills of the Altai Mountains. We studied karst phenomena in the field and in the laboratory where structural-textural properties, mineral composition and quantity of carbonate components were determined. Rivers dissected karst surface and additionally uncovered carbonate rocks. The marble layers are faulted, folded and sheared, consequently containing numerous densely spaced net of discontinuities, which are often parallel. Brittle deformations significantly increased the rocks’ porosity, consequently making it more sensitive to water absorption and freezing thaw effect. Distinct continental climate, with extreme daily and seasonal temperature variations, conditions the pronounced peeling off of the marbles along discontinuities. The diversity of disintegration is conditioned by the massive or oriented structure, cleavage, texture, and type and grain size of the marbles’ mineral constituents. Interaction and alternation of chemical dissolution and mechanical disintegration play the major role on the karren formation and its preservation. The formed karren is mostly destroyed due to peeling off and disintegration of the marbles.

Classification of discontinuities

Texture (cosmology)

10.3986/ac.v49i1.7197

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Citations (1)

Rotations of the Pohorje igneous complex (Slovenia): uplift and regional movement

EGS - AGU - EUG Joint Assembly (2003)

Emő Márton Nina Zupančič Zoltán Pécskay Mirka Trajanova Bogomir Jelen

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Miocene emplacement and rapid cooling of the Pohorje pluton at the Alpine-Pannonian-Dinaridic junction, Slovenia

Swiss Journal of Geosciences (2008)

László Fodor Axel Gerdes István Dunkl Balázs Koroknai Zoltán Pécskay

10.1007/s00015-008-1286-9

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Citations (74)

Pliocene-Quaternary river-terrace sequences in intramontane basins in the south-eastern Alpine foreland (Slovenia): characterization of morphostratigraphy and provenance

Eva Mencin Gale Petra Jamšek Rupnik Miloš Bavec Mirka Trajanova Luka Gale

This study focuses on the Pliocene-Quaternary sedimentary evolution of the fluvial systems in the Slovenj Gradec, Nazarje, Velenje, Celje, Drava-Ptuj and Kr&#353;ko Basins in the south-eastern Alpine foreland, Slovenia. The main aim was to determine the composition, morphostratigraphy, provenance, sedimentary environment and age of the deposits using geomorphological, sedimentological, geochemical, mineralogical and biostratigraphical methods. Pliocene-Quaternary sediments were deposited in fluvial (braided and wandering river systems) and alluvial/colluvial fan environments. The sediments are preserved in the terrace staircase sequences, formation of which is strongly controlled by tectonic activity. Based on geomorphological analyses, low-, middle- and high-level terrace groups were constrained and tentatively attributed to Late Pleistocene, Middle Pleistocene, and Plio-Early Pleistocene, respectively. The provenance analyses focused on the Plio-Early Pleistocene sediments and included lithological and microfacies analyses of the clasts. Based on the provenance analyses and published data, the long-term development of the drainage network was interpreted. Major changes occurred during the transition from Miocene-Pliocene and at the latest at Plio-Early Pleistocene the drainage network reached conformity with the present one. Overall, the spatial distribution of the Pliocene-Quaternary landforms revealed tectonic activity in intramontane basins during their development, from which the landscape evolution was deduced.&#160;

Early Pleistocene

Plio-Pleistocene

River terraces

10.5194/egusphere-egu21-4979

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Koro{ka Bela alluvial fan – The result of the catastrophic slope events;Karavanke Mountains, NW Slovenia)

Geologija (2008)

Jernej Jež Matjaž Mikoš Mirka Trajanova Špela Kumelj Tomaž Budkovič

The Koroška Bela alluvial fan deposits were investigated to determine the genesis of the fan and the source area of sediments. The alluvial fan is composed of a sequence of diamicton layers, and related subaeric sediments that were deposited by multiple mass flow events, in some cases certainly by debris flows. The predominant sources of sediments are tectonically deformed clastic and partly carbonate Carbonifferous and Permian rocks. In diamictons also pebbles of other rocks from the hinterland are present. These were eroded from the channel of Bela during the mass flow events. We estimate the future debris flow hazard along Bela stream as high.

Alluvial fan

Debris flow

10.5474/geologija.2008.022

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Citations (24)

Relationship between magnetic fabrics and deformation of the Miocene Pohorje intrusions and surrounding sediments (Eastern Alps)

International Journal of Earth Sciences (2020)

László Fodor Emő Márton Marko Vrabec Balázs Koroknai Mirka Trajanova

Abstract The Miocene deformation history of magmatic and host metamorphic rocks and surrounding sediments was reconstructed by measuring meso- and microscale structures and anisotropy of magnetic susceptibility (AMS) data in order to constrain the structural evolution of the Pohorje pluton during the onset of lithospheric extension at the Eastern Alps–Pannonian Basin transition. Principal AMS axes, lineation and foliation are very similar to mesoscopic lineation and foliation data from the main intrusive body and from some dykes. Although contribution from syn-magmatic texture is possible, these structures were formed during the cooling of the pluton and associated subvolcanic dykes just shortly after the 18.64 Ma pluton intrusion. Dykes emplaced during progressively younger episodes reflect decreasing amount of ductile strain, while firstly mesoscopic foliation and lineation, and then the tectonic AMS signal gradually disappears. In the structurally highest N–S trending dacite dykes, the AMS fabric only reflects the magmatic flow. The Miocene sediments underwent the same, NE–SW to E–W extension as the magmatic and host metamorphic rocks as indicated by both AMS and fault-slip data. All these events occurred prior to ~ 15 Ma, i.e., during the main syn-rift extension of the Pannonian Basin and during the fastest exhumation of the Tauern and Rechnitz windows, both demonstrating considerable extension of diverse crustal segments of the Alpine nappe pile. After a counterclockwise rotation around ~ 15 Ma, the maximum stress axis changed to a SE–NW orientation, but it was only registered by brittle faulting. During this time, the overprinting of a syn-rift extensional AMS texture was not possible in the cooled or cemented magmatic, metamorphic and sedimentary rocks.

Lineation

Transpression

Plutonism

Overprinting

10.1007/s00531-020-01846-4

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Citations (9)

Tracing widespread Early Miocene ignimbrite eruptions and petrogenesis at the onset of the Carpathian-Pannonian Region silicic volcanism

Gondwana Research (2023)

Mihovil Brlek Simon Tapster Julie Schindlbeck-Belo Sean P. Gaynor Steffen Kutterolf

Silicic

Petrogenesis

Caldera

10.1016/j.gr.2022.12.015

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Citations (16)

Migration of deformation, subsidence, and basin formation in the SW Pannonian Basin (central Europe) and the change to contractional deformation

László Fodor Attila Balázs Gábor Csillag István Dunkl Gábor Héja

The Pannonian Basin is a continental extensional basin system with various depocentres within the Alpine&#8211;Carpathian&#8211;Dinaridic orogenic belt. Along the western basin margin, exhumation along the Rechnitz, Pohorje, Kozjak, and Baj&#225;n detachments resulted in cooling of diverse crustal segments of the Alpine nappe stack (Koralpe-W&#246;lz and Penninic nappes); the process is constrained by variable thermochronological data between ~25&#8211;23 to ~15 Ma. Rapid subsidence in supradetachment sub-basins indicates the onset of sedimentation in the late Early Miocene (Ottnangian? or Karpatian, from ~19 or 17.2 Ma). In addition to extensional structures, strike-slip faults mostly accommodated differential extension between domains marked by large low-angle normal faults. Branches of the Mid-Hungarian Shear Zone (MHZ) also played the role of transfer faults, although shear-zones perpendicular to extension also occurred locally.During this period, the distal margin of the large tilted block in the hanging wall of the detachment system, the pre-Miocene rocks of the Transdanubian Range (TR) experienced surface exposure, karstification, and terrestrial sedimentation. The situation changed after ~15&#8211;14.5 Ma when faulting, subsidence, and basin formation shifted north-eastward. Migration of normal faulting resulted in fault-controlled basin subsidence within the TR which lasted until ~8 Ma.3D thermo-mechanical lithospheric and basin-scale numerical models predict similar spatial migration of the depocenters from the orogenic margin towards the basin center. The reason for this migration is found in the interaction of deep Earth and surface processes. A lithospheric and smaller crustal-scale weak zones inherited from a preceding orogenic structure localize initial deformation, while their redistribution controls asymmetric extension accompanied by the upraising of the asthenopshere and flexure of the lithosphere. Models suggest ~4&#8211;5 Myr delay of the onset of sedimentation after the onset of crustal extension and ~150&#8211;200 km of shift in depocenters during ~12 Myr. These modeling results agree well with our robust structural and chronological data on basin migration.Simultaneously with or shortly after depocenter migration, the southern part of the former rift system, mostly near the MHZ, underwent ~N&#8211;S shortening; the basin fill was folded and the boundary normal faults were inverted. The style of deformation changed from pure contraction to transpression. The Baj&#225;n detachment could be slightly folded, although its synformal shape could also be considered a detachment corrugation. Deformation was dated to ~15&#8211;14 Ma (middle Badenian) in certain sub-basins while in other sub-basins deformation seems to be continuous throughout the late Middle Miocene from ~15 Ma to ~11.6 Ma.Another contractional pulse occurred in the earliest Late Miocene, between ~11.6 and ~9.7 Ma while the western part of the TR was still affected by extensional faulting and subsidence. All these contractional deformations can be linked to the much larger fold-and-thrust belt that extends from the Southern and Julian Alps through the Sava folds region in Slovenia. Contraction is still active, as indicated by recent earthquakes in Croatia.Mol Ltd. largely supported the research. The research is supported by the scientific grant NKFI OTKA 134873 and the Slovenian Research Agency (research core funding No. P1-0195).

10.5194/egusphere-egu21-13300

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Teksturno-strukturne lastnosti glinastega skrilavca in njegov odziv na to~kovni obremenitveni test Structural and textural characteristics of slate and its response to the point load test

Mirka Trajanova

From the geomechanical point of view slate is considered to be one of more trying rock varieties. The results of research have shown close relationship between structural, textural and mineralogical characteristics on the one hand, and its strength and resistance to point loads on the other hand. Its weakened zones are the result of anisotropy. They develop mainly due to dynamo-metamorphosis of the primary mudstone, resulting in the formation of the secondary slaty cleavage, with a pronounced preferred orientation of the phyllosilicates. Low strength is the consequence of the weak Van der Waals chemical bond between individual packets of the internal crystal structure of the sheet minerals, particularly sericite. Bedding and microfolds with a crenulated structure and partial preferred orientation of sheet minerals, as well as directions that are weakened with sigmoidal shear deformations as the predecessors of microfaults, also result in significant but less problematic anisotropy. Thin lepidoblastic lamina, in apparently massive sandy metasiltstone beds in the slate represent discontinuities, which have a decisive influence on the reduction of their strength.

Classification of discontinuities

Bedding

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Significance of mylonites and phyllonites in the Pohorje and Kobansko area

Geologija (2002)

Mirka Trajanova

The wide distribution of mylonites and phyllonites in the Pohorje and Kobansko areas is the consequence of the extensive northward thrusting caused by the Cretaceous collision of the European and African plates. In the accretionary wedge meta-ultrabasites with parts of the oceanic crust were incorporated between the nappes and tectonically transported to higher levels. Ascending of the cizlakite and granodiorite melts resulted into the core structure of the Pohorje. The highest were emplaced the most metamorphosed rocks of the eclogite facies. Rocks of the Pohorje Formation continue on the other side of the Ribnica-Selnica stair-like structure in the Kobansko area. The influence of the thrusting is noticed also in the Pohorje granodiorite, which is slightly altered in the zeolite facies conditions. Part of it (Pekrska gorca) was detached and probably in the final stage of thrusting displaced for at least 11 km toward NNE. The eastern prolongation of the Pohorje massif subsided toward the Panonian basin. The pivotal Labot fault separated Pohorje and Kobansko areas from Karavanke and Strojna in Neogene. Along it the NW part of the Pohorje block was downthrown.

Mylonite

Massif

Accretionary wedge

10.5474/geologija.2002.013

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Citations (6)