•Tectonic evolution of Pannonian basin in Alpine context.•Three regional profiles.•Thin-skinned tectonics.•Regional water flow systems and tectonics.•Overwhelming drinking and thermal water ...extraction.
The Pannonian basin is an integral part of the convergence zone between the Eurasian and Nubian plates characterized by active subductions of oceanic and continental plates, and formation of backarc basins. The first part of this paper presents an overview of the evolution of the Alpine-Mediterranean region in order to understand the large scale crustal and upper mantle processes in and around the Pannonian basin, resulting a collage of terranes of Alpine and Adriatic origin. It will be followed by a summary of the history of sedimentation, volcanism and tectonic activity. As an illustration, three regional cross sections have been prepared on the base of seismic and borehole data. Reviewing current tectonic ideas and models, we come up with a speculative tectonic scenario depicting Alcapa and Tisza-Dacia as orogenic wedges detached from their mantle lithosphere in the Alpine and Adriatic/Dinaric collision zone during the Late Oligocene to Early Miocene. They suffered a dramatic thermal impact leading to crustal melting during extrusion, when these crustal flakes could have been directly superimposed on the asthenosphere in the Carpathian embayment. Since then, the large part of the Pannonian has been cooling and a new mantle lithosphere growing. Geothermal data show that the Pannonian basin with cessation of volcanic activity in the Late Miocene is still very hot and Miocene to Quaternary clastic basin fill, together with karstified Mesozoic carbonates form good geothermal reservoirs of regional extent. In addition to these gravity-driven aquifer systems, a strongly overpressured reservoir can be found below a regional pressure seal in synrift strata and fractured basement rocks. Eventually, we show maps of geothermal installations in the Pannonian basin and suggest that at the present level of knowledge and geophysical surveying it is easy to find additional resources, however proper water management is a critical issue to avoid harmful drawdown of the groundwater table.
Gomance is a piedmont karst polje in the northern Dinaric Alps presenting geomorphological and sedimentological evidence of past glaciation. During the Pleistocene the polje was situated at the edge ...of the Snežnik and Gorski Kotar ice fields from where two outlet glaciers reached Gomance. The morphogenesis of the polje was reconstructed by means of geomorphological mapping, sedimentological studies, and ground penetrating radar (GPR) measurements, supported by hand-drillings. With GPR an almost entirely buried moraine system was also imaged and mapped, crucial in reconstructing the polje history. The depression was karstified and well drained without any surface streams before the Last Glaciation. When the glacier front reached the depression, the entire floor became covered by glacial and outwash deposits. Surface runoff dominated over karst drainage in a large part of the polje, particularly where distal outwash deposits with low effective porosity functioned as an aquitard. These deposits diverted surface drainage toward the lowest edge of the polje, which functioned as a ponor front along the entire length. The outwash system of the Gomance polje was active during the Last Glaciation as suggested by radiocarbon-dated outwash deposits.
Display omitted
•Polje history reconstructed through geomorphology, sedimentology and GPR•Karst polje evolution related to glaciation•Glacigenic infill of the polje functioning as an aquitard•Evidence of Pleistocene glaciation in the northern Dinaric Alps
The Po-Adriatic region offers an excellent case for reconstructing sediment provenance and transport pathways of a multi-sourced sediment-routing system. Through a comprehensive set of ∼1400 ...geochemical data, a model for provenance and sediment flux was built based on distinct compositional fingerprints of 53 fluvial systems and their comparison to coastal, shelf and deep-marine sediments. Geochemically unique catchment lithologies (mafic/ultramafic rocks, limestones and dolostones) were used as end-members to assess exclusive source-rock signatures. Following calibration with sedimentary facies, selected key elements and element ratios poorly sensitive to particle size (Ni/Cr, MgO, Ni/Al2O3, Cr/V, Ca/Al2O3 and Ce/V) were adopted as provenance indicators. The high-Ni and high-Cr source-rock signature of mafic/ultramafic rocks widely exposed in the Po River watershed and along the Albanian Dinarides contrasts markedly with the high-Ca (and locally high-Mg) geochemical composition of Eastern Alpine, Apennine, and Eastern Adriatic (Montenegro, Croatia, Slovenia) river catchments, which are, instead, carbonate-rich and virtually ophiolite-free. Relatively high Ce values from Apulian river samples serve as a key marker for a minor, but very distinct sediment provenance from southern Apennine alkaline volcanic rocks.
Despite along-shore mixing and dilution with sediment sourced from other river catchments, the geochemical signature of Adriatic shelf muds primarily reflects composition of sediment eroded from the contiguous continental areas. Chromium-rich and nickel-rich detritus generated in mafic and ultramafic complexes of the Western Alps and conveyed through the Po River into the Adriatic Sea records a geochemical signal that can be traced downstream as long as 1000 km, from the Alpine zone of sediment production to the area of final deposition, offshore Apulia.
While longitudinal dispersion linked to the general cyclonic, counter-clockwise Adriatic circulation is prevailing along the Western Adriatic Sea, conspicuous detrital input from transversal pathways to the deep sea is revealed across the Eastern Adriatic shelf using heavy metals as provenance tracers. Estimates of fluvial sediment loads and compositional fingerprinting of fluvial, coastal and shelf sediments indicate that previously neglected ophiolite-rich successions of Albania represent a major sediment-conveyor to the offshore sinks (Southern Adriatic Deep and Mid-Adriatic Deep) through significant cross-shore and NNW-directed sediment transport in the Eastern Adriatic Sea. A cut-off value of the Ni/Cr ratio targeted around 0.8 represents an effective tool for the differentiation in marine sediments of Ni-rich (serpentine-rich) ophiolite detritus of Albanian origin from mafic/ultramafic sources of Alpine affinity. High trace-metal contents found within the Adriatic deep basin are mostly of natural origin and only minimally reflect metal contamination.
A new genus of the tribe Ephippigerini, Dinarippiger Skejo, Kasalo, Fontana et Tvrtković gen. nov., is described based on the characters of occiput coloration, tegmina coloration, cerci and pronotum ...shape. The new genus is morphologically intermediate between the genera Ephippiger Berthold, 1827 and Uromenus Bolívar, 1878, and presently includes only Dalmatian Saddle Bush Cricket, Dinarippiger discoidalis (Fieber, 1853) comb. nov., hitherto known as Ephippiger discoidalis Fieber, 1853. The species inhabits NE Italy (mainly Carso Triestino), SW Slovenia, Croatia, Bosnia & Herzegovina, and Montenegro, i.e., islands and karst habitats along the eastern Adriatic coast, with isolated findings in Albania and Italy. Its prominent variation in size and coloration has already produced many synonyms (= limbata Fischer, 1853, = limbata var. major Krauss, 1879, = limbata var. minor Krauss, 1879, = selenophora Fieber, 1853, = sphacophila Krauss, 1879), which may suggest that what is currently regarded as a single species could represent a complex of distinct species with restricted distributions. This study also presents an annotated distribution map and a bioacoustic analysis of D. discoidalis comb. nov. Further research, especially adopting molecular methods, is necessary to assess possible cryptic diversity within the genus Dinarippiger gen. nov. and elucidate its evolutionary history.
We present a paleoenvironmental reconstruction for the mountain fringe between the South-Eastern Alps and the Northern Dinarides (NE-Italy/W-Slovenia) during the Last Glacial Maximum. We focused on a ...new sedimentary and paleoecological archive spanning the LGM acme, located in an aggrading, permanently flooded and ponded plain, dammed by an active fluvioglacial megafan. The ecosystem reconstruction, based on two high resolution pollen records, is supported by a rich plant macrofossil flora and constrained by a robust radiocarbon chronology between 26 and 22calka BP. We show evidence for persistence of boreal trees and of different open boreal forest types throughout the LGM at the south-eastern mountain fringe of the Alps and the Northern Dinarides. Fire frequency is responsible for high, oscillating forest openness. The paleobotanical record is discussed in the light of the ecogeographic diversity of the region. A belt formed by Swiss stone pine, larch and dwarf mountain pine on limestone bedrock, and accompanied by Spruce in the floodplain, extended uphill, while proximal outwash plain supported Scots pine and dwarf mountain pine. These differences arise from groundwater regimes rather than from local climate variability. A steep moisture gradient from the semiarid pedoclimatic regime prevailing in the Adriatic alluvial plain to the forested mountain fringe is related to the orographic rainout triggered by southern air circulation. Mesophytic broad-leaved forest trees did not withstand the LGM temperature extremes in zonal ecosystems at the Alpine–Dinaric fringe; however, the fossil evidence suggests a number of microrefugia in karstic and thermal spring habitats of the northern Adriatic.
•Paleoenvironmental reconstruction at Alps–Dinarides fringe during the Last Glacial Maximum•Relationships between regional geological frame, sedimentary environments, and forest history•Persistence of trees and of different types of open boreal forest throughout the LGM
Intense stratal disruption and lithological mixing is generated during sedimentary transport events, highlighting that gravitational processes are efficient mechanisms in the production of different ...types of mass transport deposits (MTDs) with internal block-in-matrix arrangement. Extra- and intrabasinal MTDs exhumed in orogenic belts worldwide, identified as olistostromes and sedimentary mélanges in the first case, record the final products of the downslope evolution of landslide masses, from slope failures to gravity flows. Specific sedimentary fingerprints are commonly preserved within such “chaotic” rock units, even though usually reworked by polyphased tectonics and associated metamorphism. One of the main conceptual issues in this framework is the occurrence/incorporation of “exotic” clasts and blocks (baseline criterion for mélange definition). We here provide an outline of the primary, multi-scale structures identified in key case studies from the northern Apennines of Italy and the northwestern Dinarides in Slovenia. We focus on mechanisms responsible for the entrainment of intra- (native) and extra- (exotic) basinal material and its progressive deformation. Important information, such as the kinematics of processes and internal strain partitioning, can be reconstructed from the study of such features, providing fundamental paleographic and paleo-physiographic constraints, as well as consolidating the basis for a possible updated reappraisal of some classic mélanges.
Display omitted
•(Un)mixing of intra- (native) and extrabasinal (exotic) material;•Deep basal substrate erosion during slide emplacement;•Rearrangement of depositional physiography by removal of paleobathymetric highs;•Slide detachment undercutting into older tectonic-stratigraphic units.
On 28 December 2020, seismic activity in the wider Petrinja area strongly intensified after a period of relative seismological quiescence that had lasted more than 100 years (since the well-known ...M5.8 Kupa Valley earthquake of 1909, which is known based on the discovery of the Mohorovičić discontinuity). The day after the M5 foreshock, a destructive M6.2 mainshock occurred. Outcomes of preliminary seismological, geological and SAR image analyses indicate that the foreshocks, mainshock and aftershocks were generated due to the (re)activation of a complex fault system—the intersection of longitudinal NW–SE right-lateral and transverse NE–SW left-lateral faults along the transitional contact zone of the Dinarides and the Pannonian Basin. According to a survey of damage to buildings, approximately 15% of buildings were very heavily damaged or collapsed. Buildings of special or outstanding historical or cultural heritage significance mostly collapsed or became unserviceable. A preliminary analysis of the earthquake ground motion showed that in the epicentral area, the estimated peak ground acceleration PGA values for the bedrock ranged from 0.29 to 0.44 g. In the close Petrinja epicentral area that is characterized by the superficial deposits, significant ground failures were reported within local site effects. Based on that finding and building damage, we assume that the resulting peak ground acceleration (PGAsite) values were likely between 0.4 and 0.6 g depending on the local site characteristics and the distance from the epicentre.
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 north-east 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 basin – the Central Carpathian Paleogene Basin. In the Northern Hungarian Paleogene retro-arc basin, turbidites covered a carbonate platform in the same time. During the Early Oligocene, the rock uplift of the Alpine-Carpathian junction area continued and the Mesozoic sequences of the Danube Basin basement were removed, along with a large part of the Eocene Hungarian Paleogene Basin fill, while the retro-arc basin depocentres migrated toward the east. The Rupelian basins gained a character of semi-closed sea spreading from the Magura Basin across the Central Western Carpathians up to the Hungarian Paleogene Basin. In the Late Oligocene, the Magura Basin connection with the Northern Hungarian Paleogene Basin remained open, probably along the northern edge of the Tisza microplate, and anoxic facies were substituted by open marine environments.
•Re-evaluation of the Western Carpathians geodynamics during the Paleogene•New model of the Paleogene basin evolution and paleogeography•Definition of two broad-scale tectonic settings of the Paleogene basins•Palinspastictic and paleotopographic maps for the main time slices
Understanding the structural and kinematic effects of indentation is still debated due to the large number of competing mechanisms associated with the complex orogenic build-up. Among the many ...examples available worldwide, the evolution of the Adriatic continental microplate in the Mediterranean domain provides one of the best places to understand the mechanics of indentation. This understanding is hampered by the lack of structural and kinematic data in the Dinarides, an orogen situated at the critical transition between the Alps, Albanides and Hellenides, and across the Adriatic margin of the Apennines. We have studied the less known area of the central and south-eastern Dinarides by focussing on collecting a new kinematic dataset for structures formed during the Adriatic indentation, which postdates the main Late Jurassic – Paleogene orogenic structuration. Our results are in agreement with previous interpretations of an early-middle Miocene period of extension that affected the entire orogen across its strike and is incompatible with indentation effects in the studied parts of the Dinarides. More importantly, we demonstrate for the first time that the post- middle Miocene Dinarides deformation was characterized by a coherent regional system of large offset dextral strike-slip faults, which transfer gradually their offsets to thrusts and high-angle reverse faults. The overall deformation transfer mechanism can be described as a special class of continental restraining bends or stepovers, whose geometry is controlled by rheological distribution. The integration of our results in the larger geodynamic context shows that the post-middle Miocene Dinarides fault system accommodates the differential motion between the N- to NE-wards Adriatic indentation and the rapid S- to SW- ward movement of a Hellenides area situated SE of the Kefalonia Fault, driven by the Aegean slab-roll back.
•Along-strike transfer of deformation during indentation and subduction;•Across-strike transfer of deformation accommodated by the interplay between strike-slip and reverse faulting;•Continental restraining bends and stepovers controlled by rheological distribution;•Regional Dinarides fault system accommodating the differential motion between the Adriatic indentation and Aegean slab roll-back.
One of the most common observation in Mediterranean areas is the migration of contractional deformation and associated slabs through time toward external orogenic areas, associated with lower plate ...crustal accretion. The Dinarides orogen of Central Europe is an optimal place to study such a sequence of contractional deformation. Compared with other areas, contraction in the Dinarides was less overprinted by subsequent extension, while a remnant of the subducted slab is observed in a far external orogenic position. Understanding the deformational evolution of the Dinarides is hampered by the reduced availability of kinematic studies. Therefore, we have performed a surface kinematic study in the external parts of the Dinarides. By correlating with available geophysical and evolutionary constraints, we constructed two large‐scale, kinematically controlled regional transects. The results demonstrate a long‐lived evolution of shortening that affected the Dinarides lower orogenic plate. While the Late Jurassic‐earliest Cretaceous deformation was associated with an earlier obduction moment, the latest Cretaceous onset of continental collision has gradually focused deformation at inherited rheological weakness zones. We show that shortening was interrupted by a period of Miocene extension that affected all orogenic areas and created the Dinarides Lake System. The extension was followed by renewed shortening, which started during the latest Miocene and remains presently active, whose kinematics in the central and SE part of the Dinarides is revealed for the first time by our study. These results indicate a lower plate crustal accretion mechanism that was spatially and temporally connected with gradual slab retreat in the Dinarides.
Key Points
The migration of contractional deformation in the Dinarides can be associated with lower plate crustal accretion during slab rollback
Along the Dinarides orogenic strike there is a lateral variability of contractional deformation
The entire Dinarides orogen was affected by Miocene extension and subsequent inversion
PDF
