miocene rotations in the eastern alps palaeomagnetic results from intramontane basin sediments a palaeomagnetic study of late early miocene to late middle miocene sediments from the eastern alpine intramontane basins revealed counterclockwise rotations in the ennstal in the western part of the noric and in the lavanttal depressions for the basal strata of the basins declinations are between 273 and 315 while for the younger strata they are between 321 and 333 in perfect agreement with observations from the klagenfurt basin the results suggest synsedimentary rotation during the lateral tectonic extrusion of the eastern alps ca 17 13 ma which was also responsible for the formation of the mostly transtensional basins we propose a model in which domino shaped blocks separated by nnw sse trending dextral faults rotated counterclockwise due to faster eastward motion in the south relative to areas further north the protrusion of the bohemian spur inhibited eastward motion in the northern part of the study area thus creating a sinistral wrench corridor after lateral extrusion had ceased the counterclockwise rotation continued probably as en bloc rotation of ca 30 clockwise rotation was observed in the eastern part of the noric depression which appears to belong to a limited area with complex rotation pattern near the eastern margin of the alps this area is wedged between the counterclockwise rotated eastern alps and the similarly rotated north pannonian area in hungary 2000 elsevier science b v all rights reserved

geophysical geological transect and tectonic evolution of the swiss italian alps a complete alpine cross section integrates numerous seismic reflection and refraction profiles across and along strike with published and new field data the deepest parts of the profile are constrained by geophysical data only while structural features at intermediate levels are largely depicted according to the results of three dimensional models making use of seismic and field geological data the geometry of the highest structural levels is constrained by classical along strike projections of field data parallel to the pronounced easterly axial dip of all tectonic units because the transect is placed close to the western erosional margin of the austroalpine nappes of the eastern alps it contains all the major tectonic units of the alps a model for the tectonic evolution along the transect is proposed in the form of scaled and area balanced profile sketches shortening within the austroalpine nappes is testimony of a separate cretaceous age orogenic event west directed thrusting in these units is related to westward propagation of a thrust wedge resulting from continental collision along the meliata hallstatt ocean further to the east considerable amounts of oceanic and continental crustal material were subducted during tertiary orogeny which involved some 500 km of n s convergence between europe and apulia consequently only a very small percentage of this crustal material is preserved within the nappes depicted in the transect postcollisional shortening is characterized by the simultaneous activity of gently dipping north directed detachments and steeply inclined south directed detachments both detachments nucleating at the interface between lower and upper crust large scale wedging of the adriatic or apulian lower crust into a gap opening between the subduced european lower crust and the pile of thin upper crustal flakes alpine nappes indicates a relatively strong lower crust and detachment between upper and lower crust

neotectonics of the somogy hills part ii evidence from seismic sections abstract the somogy hills are located in the pannonian basin south of lake balaton hungary above several important tectonic zones analysis of industrial seismic lines shows that the pre late miocene substratum is deformed by several thrust faults and a transpressive flower structure basement is composed of slices of various palaeo mesozoic rocks overlain by sometimes preserved paleogene thick early miocene deposits middle miocene partly overlying a post thrusting unconformity partly affected by the thrusts is also present late miocene thick basin fill forms onlapping strata above a gentle paleo topography and it is also folded into broad anticlines and synclines these folds are thought to be born of blind fault reactivation of older thrusts topography follows the reactivated fold pattern especially in the central western part of the study area the map pattern of basement structures shows an eastern area where ne sw striking thrusts folds and steep normal faults dominate and a western one where e w striking thrusts and folds dominate folds in late neogene are also parallel to these directions a ne sw striking linear normal fault and associated n s faults cut the highest reflectors the ne sw fault is probably a left lateral master fault acting during after late miocene gravity anomaly and pleistocene surface uplift maps show a very good correlation to the mapped structures all these observations suggest that the main early miocene shortening was renewed during the middle and late miocene and may still persist two types of deformational pattern may explain the structural and topographic features a nw se shortening creates right lateral slip along e w faults and overthrusts on ne sw striking ones another nne ssw shortening creates thrusting and uplift along e w striking faults and transtensive left lateral slip along ne sw striking ones traces of both deformation patterns can be found in quaternary exposures and they seem to be consistent with the present day stress orientations of the pannonian basin too the alternation of stress fields and multiple reactivation of the older fault sets is thought to be caused by the northwards translation and counter clockwise rotation of adria and the continental extrusion generated by this convergence

intrinsic and scattering attenuation of high frequency s waves in the central part of the external dinarides abstract the central part of the external dinarides ced is a geologically and tectonically complex region formed in the collision between the adriatic microplate and the european plate in this study the contributions of intrinsic and scattering attenuation q i 1 and q sc 1 respectively to the total s wave attenuation were calculated for the first time the multiple lapse time window analysis mltwa method based on the assumptions of multiple isotropic scattering in a homogeneous medium with uniformly distributed scatterers was applied to seismograms of 450 earthquakes recorded at six seismic stations selected events have hypocentral distances between 40 and 90 km with local magnitudes between 1 5 and 4 7 the analysis was performed over 11 frequency bands with central frequencies between 1 5 and 16 hz results show that the seismic albedo of the studied area is less than 0 5 and q i 1 q sc 1 at all central frequencies and for all stations these imply that the intrinsic attenuation dominates over scattering attenuation in the whole study area calculated total s wave and expected coda wave attenuation for ced are in a very good agreement with the ones measured in previous studies using the coda normalization and the coda q methods all estimated attenuation factors decrease with increasing frequency the intrinsic attenuation for ced is among the highest observed elsewhere which could be due to the highly fractured and fluid filled carbonates in the upper crust the scattering and the total s wave attenuation for ced are close to the average values obtained in other studies performed worldwide in particular good agreement of frequency dependence of total attenuation in ced and in the regions that contributed most strong motion records for ground motion prediction equations used in psha in croatia indicates that those were well chosen and applicable to this area as far as their attenuation properties are concerned

miocene pliocene tectonic evolution of the slovenian periadriatic fault implications for alpine carpathian extrusion models the periadriatic line pal is a remarkable several hundred kilometer long fault system of the alpine orogen its dextral character was documented by several authors using diverse criteria but detailed kinematics and timing of movements had not been investigated along its whole length structural and paleomagnetic measurements mapping and stratigraphic and sedimentological studies have helped to unravel the miocene pliocene evolution of the slovenian segment of the pal brittle deformation was characterized by nw se to n s compression and perpendicular tension deformation has resulted in dextral strike slip faulting folding and tilting of beds the first transpressional event corresponds to the first phase of lateral extrusion of the east alpine western carpathian northern pannonian block in the early miocene 24 17 5 ma after a short period of transtension during the karpatian 17 5 16 5 ma dextral transpression reoccurred during the middle miocene to pliocene and lasted up to the quaternary middle miocene dextral slip can be connected to the second phase of extrusion the highly deformed rocks within the dextral shear zones show variable clockwise sometimes counterclockwise rotations the mechanism of rotation seems to be complex ranging from regional rotation to local folding due to pure or simple shear domino type rotation

magnetostratigraphy and small mammals of the late oligocene banovici basin in ne bosnia and herzegovina article i nfo a combined magnetostratigraphic and small mammal investigation was carried out to acquire better age control on the sedimentary infill of the banovici basin in bosnia and herzegovina although the dinarides occupy a crucial paleogeographic position bridging central europe and anatolia no detailed records of its small mammal fauna have been published until now a rich small mammal assemblage with over 500 molars was excavated from a section exposing marls and clays just underlying the basins main coal layer the fauna of this turija small mammal locality compares best with the uppermost oligocene to lowermost miocene localities from the european mp30 mn1 mammal zones and with anatolian zone b from central turkey a 160 m thick series of lacustrine sediments overlying the main coal layer in the nearby grivice section was sampled for paleomagnetic purposes the magnetostratigraphic pattern of the grivice section comprises a long reversed interval a subsequent short normal interval and another reversed interval the most logical correlation of this pattern to the late oligocene part of the geomagnetic polarity time scale gpts is to chrons c6cr c6cn 3n and c6cn 2r 24 to 23 2 ma this correlation implies a sedimentation rate of 20 cm kyr for the banovici basin and an age of approximately 24 ma for the turija mammal site the proposed correlation fits well with other magnetostratigraphically calibrated mammal records in western and central europe as well as anatolia and with the recalibrated ages of 24 95 0 05 ma and 24 72 0 04 ma for two basalt flows bracketing the enspel mp28 site in southern germany our results indicate that a limited exchange of fauna from central asia to western europe existed in late oligocene and miocene times

geodynamic evolution of the northern dinarides and the southern part of the pannonian basin abstract most of the recent geodynamic interpretations of the pannonian basin focus on its relation to the formation of the carpathians and the alpine orogeny however also the dinarides were severely affected by neogene tectonics related to the formation of the pannonian basin especially in the northernmost dinarides neogene deformation played a very important role in the evolution of this mountain chain geological records clearly show evidence of two phases of plate convergence along the northern and eastern margins of the present day dinarides at the end of the jurassic the dinaridic parts of the tethys ophiolites were obducted onto the northeastern margins of the apulian microplate the second phase is documented in the central part of the northernmost dinarides it is genetically related to an ancient volcanic arc as indicated by late cretaceous palaeogene trench sediments with blueschist olistolithes which are interlayered by basalt rhyolites pyroclastics medium pressure metamorphosed trench sediments and associated synkinematic granitoids in the northern part of the dinarides subduction processes terminated with the eocene compressional event which caused the uplift of the dinarides numerous intramontane basins with shallow marine fluviatile and lacustrine deposits were generated during the oligocene penecontemporaneous andesites which are found along the drava and sava depressions of the south pannonian neogene basin can be correlated with the easternmost periadriatic tonalites however observations do not indicate strike slip faulting at that time in this area the neogene rift stage initiated the evolution of the pannonian basin it is marked by extruded submarine trachyandesites of karpathian age badenian basalts andesites dacites and rhyolites and pannonian alkali basalts which are interlayered by coeval sedimentary rocks main evidence for the large scale tectonic transport of large dinaridic blocks into the pannonian basin area are the periadriatic sava and zagreb zemplen fault systems and subparallel faults the late sarmatian global sea level drop which coincided with a compressional phase is regionally marked by an unconformity throughout the pannonian basin as reported by horvath horvath f 1995 phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration mar pet geol 12 8 837 844 due to thermal subsidence during the pliocene more than 2000 m of lacustrine freshwater sediments were deposited in the south pannonian basin the pliocene compression phase can be observed in the transdanubian zone and also south of the mura and drava rivers by south and southwest dipping reverse fault systems

eoalpine and mesoalpine tectonics in the southern alps according to structural and stratigraphic data eoalpine and mesoalpine tectonics can be clearly recognized in the southern alps and distinguished from the better known neoalpine deformation

neogene quaternary structures in the border zone between alps dinarides and pannonian basin hrvatsko zagorje and karlovac basins croatia analysis of neogene quaternary structures from seismic lines surface measurements and geological mapping is presented from the border zone between the alps dinarides and pannonian basin first early miocene extension was possibly characterised by ene directed extension it was partly synchronous with nw se shortening second middle miocene extension was possibly characterised by nw se to wnw ese directed extension again this event was followed by a new generation of thrusts related to end sarmatian shortening the last late miocene e w to wnw ese directed extension was followed by a final shortening that created major map scale folds basement pop ups and inverted former basins geometry onlap and thickness patterns of the youngest syn tectonic basin fill indicate that this last n s to nw se directed shortening started in late pontian and continued up to the present time when taking into account the wider surrounding area it seems that the structures related to this latest shortening are arranged in often perpendicular directions centred at the eastern end of the periadriatic lineament to explain this fan like pattern of synchronous shortenings a kinematic model is proposed combining counter clockwise rotation with north or northwestward shift of the dinaridic block with respect to the more stable alpine buttress

tertiary palaeomagnetic data for the carpatho pannonian region in the light of miocene rotation kinematics abstract the tectonic interpretation of the palaeomagnetic data for the neogene history of the carpatho pannonian region has usually been based on the palaeomagnetic data for the pre cenozoic complexes here a review of the tertiary palaeomagnetic data is given for the sites with two or more sets of data new site mean directions are calculated for most areas new area mean directions are given with a uniform criterion for the limitation of the normally distributed sub populations based on radiometric data some neogene volcanic sequences are subdivided into two complexes with separate area mean directions the possible influence of the areal tilts on the area mean palaeomagnetic directions is analysed and conclusions on the horizontal rotations are drawn the palaeomagnetic rotations are interpreted in the light of the author s kinematic model for the neogene history of the carpatho pannonian region the rotation of both the southeastern unit by about 100 clockwise and the northwestern unit by about 35 anti clockwise are supported by palaeomagnetic data in addition some rotations predicted by the model are documented by palaeomagnetic data as follows 1 the anti clockwise rotation of the flanks of the darno line gemer bukk area with sinistral displacements in the early miocene 2 the anti clockwise rotations along the southeastern margin of the northwestern unit with sinistral displacements before 10 ma 3 the anti clockwise rotation of the ukrainian carpathians before 12 ma some palaeomagnetic rotations have not been predicted by the kinematic model but occur in the regions where deformations are quite probable these unexpected palaeomagnetic rotations throw a new light on some details of the kinematics 1 the advance of the outer west carpathian nappes later than 14 ma is documented by the increased palaeomagnetic inclination of the pieniny andesites 2 the movement of the central and inner west carpathians later than 12 ma is recorded in the palaeomagnetic rotations of the central and east slovakian volcanites this movement seems to reflect a bay of thin crust within the underthrust european plate margin or more precisely the reaction of the eastern contour of the bay on the drag of the northwestern unit towards the northeast by the still rotating southeastern unit the rotation and deformation of the northwestern unit in the miocene have to be taken into account in the reconstructions of the pre neogene situations since they intensely influenced the arrangement of all older palaeotectonic and palaeogeographic zones the southeastern unit also suffered intense rotation and deformation in the miocene unfortunately there are almost no palaeomagnetic data available for its tertiary complexes

complex structural pattern of the alpine dinaridic pannonian triple junction due to the political boundaries between the central european countries on one hand and the thick tertiary cover in the pannonian basin on the other the eastward continuation of the alpine and dinaridic units has been ambiguous and poorly documented based on comparative analyses the aim of the present paper is to define the pre tertiary structural units in the junction area of the alpine dinaridic and pannonian regions in the sw part of the pannonian basin and to draw conclusions on the continuation of the alpine and dinaridic units according to diagnostic characteristics of the periadriatic lineament system the balaton lineament system may be considered as its direct eastern continuation north of the periadriatic balaton lineament system the transdanubian range unit due to its pre tertiary paleogeographic setting shows mainly south alpine facies relations however its present structural position is identical to that of the upper austroalpine nappes between the periadriatic balaton and zagreb zemplin lineament systems heterogeneous structural units are juxtaposed forming the sava composite unit in the northern part of this composite unit non metamorphosed nappes occur which can be considered the eastern continuation of the south alpine units these nappes are overthrust onto internal dinaridic units in the tertiary the zagreb zemplin mid hungarian lineament separates the sava unit from the tisza unit showing close affinity to the tethyan margin of the eurasian plate during the early stage of the alpine evolution

geodynamic evolution of the central dinarides abstract the central part of the dinarides unlike the northwestern and southeastern dinarides shows a consistent pattern in the distribution of the large tectonostratigraphic units from southwest apulia to northeast the following five main units originating in different parts of the mesozoic tethys can be distinguished 1 adriatic dinaridic carbonate platform formations 2 carbonate clastic units flysch bosniaque of the passive continental margin 3 ophiolite bearing formations of the dinaridic ophiolite zone also containing radiolarites greywackes and shales including melange formations and overstepped late jurassic to cretaceous cover sequences 4 active continental margin units represented by upper cretaceous palaeogene trench sediments with blueschists tectonized ophiolite melange alpine medium pressure metamorphic rocks originated from upper cretaceous palaeogene sediments and alpine synkinematic granitoids 5 a nappe consisting of allochthonous palaeozoic triassic formations which is thrust onto the ophiolites and genetically related sedimentary formations the frontal parts of this nappe directly overlie the northeastern margin of the adriatic dinaridic carbonate platform i e the external dinarides the evolution of the central dinarides was controlled by a sequence of tectonic events which took place within the alpine cycle 1 rifting processes lasting some 40 50 ma which started in the late permian and ended in the norian 2 opening of the oceanic dinaridic tethys commenced in the late triassic and persisted for some 70 80 ma until the end of the jurassic 3 subduction processes and emplacement of ophiolites started in late jurassic early cretaceous times during the closing phase of the dinaridic ocean or dinaridic tethys the palaeozoic triassic nappe was emplaced on the ophiolites the thrusting was accompanied by alpine metamorphism 120 100 ma 4 the main alpine deformational event and medium pressure metamorphism with synkinematic granite plutonism took place in late eocene early oligocene times when the ophiolite and palaeozoic triassic nappes were emplaced on the adriatic dinaridic carbonate platform which at the same time was deformed resulting in the development of the external dinarides fold and thrust belt

seismicity and earthquake focal mechanisms in north western croatia article i nfo the seismicity of nw croatia seismically the most vulnerable part of the country is presented based on historical records and reanalysed and relocated earthquakes occurring after 1908 the improved picture of the distribution of seismicity shows consistent grouping of foci in space mostly within eight epicentral areas the database of fault plane solutions has been considerably enlarged and now lists 22 earthquakes the earthquake mechanisms consistently reveal the subhorizontal to moderately dipping p axis predominantly n s directed in the central part of studied area to nw se and ne sw directed in the western and eastern parts respectively they indicate the prevalence of compressional tectonics with reverse faulting in the central part versus strike slip motions in the western and eastern sectors these data are in agreement with stress calculations and kinematics of quaternary structures obtained by geological studies the completeness of the catalogue estimated by comparing the cumulative activity rate for a large number of subcatalogues to the reference contemporary rate exhibits large spatial heterogeneity taking this into account we have computed and mapped the parameters of the frequency magnitude recurrence relation the b value and the activity rate

tertiary evolution of the intra carpathian area a model abstract the outer carpathian flysch nappes encircle an intra carpathian domain which can be divided into two megatectonic units north pannonian and tisza mostly on the basis of contrasting mesozoic and palaeogene facies development we see two major kinematic problems to be solved 1 1 the present distribution of the mesozoic and palaeogene facies is mosaic like and some belts form exotic bodies within realms of austroalpine affinity 2 2 late eocene palinspastic reconstruction of the outer carpathian flysch nappes suggest that the entire intra carpathian area must have been located several hundreds of kilometres to the south and to the west of its present position neogene extension can account for shortening in the external carpathian nappes but is unable to explain mesozoic facies anomalies and offsets of palaeogene formations we suggest that evolution of the intra carpathian area involved first late palaeogene early miocene juxtaposition of the north pannonian and tisza megatectonic units accompanied by the closure of the external carpathian flysch troughs thereafter extension of this amalgamated unit occurred which was compensated by thrusting of flysch nappes onto the european foreland and formation of molasse foredeeps eastward escape of the north pannonian unit from the alpine collisional belt involved left lateral shear along the pieniny klippen belt and right lateral shear along the mid hungarian zone parts of the late palaeogene basin and an early miocene volcanic edifice were dissected offset and elongated by several 100 kms the driving mechanism of the eastward escape of the intra carpathian area can be related to the collision of apulia and europe and the subduction of the external carpathian crust under the pannonian units the escape ceased gradually in the early miocene when oblique collision between the north pannonian unit and european continent occurred neogene extension of the pannonian region was an areal deformation the extension at locally variable rate resulted in the break up of the heterogenous floor of the neogene basin the driving mechanism of basin extension and contemporaneous compressional deformation of the external carpathians is thought to be related to ongoing subduction involving the marginal part of the attenuated european continental crust tectonic activity in the carpathians and basin subsidence and volcanism shifted in time and in unison from the west toward the east southeast

the tectonic evolution of a critical segment of the dinarides alps connection kinematic and geochronological inferences from the medvednica mountains ne croatia the transition zone between the alps and dinarides is a key area to investigate kinematic interactions of neighboring orogens with different subduction polarities a study combining field kinematic and sedimentary data microstructural observations thermochronological data rb sr and fission track and regional structures in the area of medvednica mountains has revealed a complex polyphase tectonic evolution we document two novel stages of extensional exhumation the first stage of extension took place along a late cretaceous detachment following the late early cretaceous nappe stacking burial and greenschist facies metamorphism two other shortening events that occurred during the latest cretaceous oligocene were followed by a second event of extensional exhumation characterized by asymmetric top ne extension during the miocene top nw thrusting took place subsequently during the pliocene inversion of the pannonian basin the cretaceous nappe burial late cretaceous extension and the oligocene earliest miocene contraction are events driven by the alps evolution in contrast the latest cretaceous eocene deformation reflects phases of dinaridic contraction furthermore the miocene extension and subsequent inversion display kinematics similar with observations elsewhere in the dinarides and eastern alps all these processes demonstrate that the medvednica mountains were affected by alpine phases of deformations to a much higher degree than previously thought similarly with what has been observed in other areas of contractional polarity changes such as the mediterranean black sea or new guinea systems the respective tectonic events are triggered by rheological weak zones which are critical for localizing the deformation created by both orogens

gravity flow dominated sedimentation on the buda paleoslope hungary record of late eocene continental escape of the bakony unit the upper eocene sequence of the buda hills consists of fluvial and shallow marine conglomerates sandstones bioclastic shallow water limestone marlstone and pelagicglobigerina marl the succession illustrates rapid overall subsidence of the area from terrestrial environments to bathyal depths sedimentation occurred on slopes situated on the flanks of synsedimentary basement antiforms vertical growth of antiforms caused progressive tilting of beds layer parallel extension by boudinage and faulting and induced redeposition by mass flow antiforms are localised in the dextral budaors shear zone and in the buda imbricate stack which accommodated the dextral displacement the latter is underlain by blind reverse faults probably merging into a detachment fault at shallow depths these structures were formed by wnw ese oriented compression and nne ssw directed tension the morphological expression of the imbricate stack is the se facing buda slope the bakony unit while escaping from the alps was bordered by a northern sinistral and a southern dextral shear zone synsedimentary tectonics in the buda hills demonstrates the style of deformation inside the escaping block close to the southern border zone tectonically controlled sedimentation suggests that escape tectonics was active as early as late eocene time

tectonic activity in the croatian part of the pannonian basin abstract three main stages in structural development of the sw pannonian basin are differentiated the onset of extensional tectonics between the oligocene and the early miocene main extensional processes in the early and middle miocene and prevailing transpression in the pliocene and quaternary the neotectonic phase is given special attention in this paper structural fabrics allow to subdivide the area into three large structural zones corresponding to the western southern and central marginal part of the pannonian basin in croatia these zones are bounded by important faults the periadriatic drava fault the medvednica fault zone and the southern marginal fault of the pannonian basin the recent displacements within the dinarides and the eastern alps form the boundary conditions for active transpressional deformation in the western marginal part of the pannonian basin dextral transcurrent displacement is evident in the zone of the periadriatic drava wrench fault the formation of the new types of structures is observed especially in zones of compression along the faults narrowing of the area between the sava and drava rivers causes structural changes in the marginal parts of the corresponding basins i e in the areas close to the slavonian mts recent tectonic activity is marked by the occurrence of earthquakes which are most common in the northwestern part of croatia the spatial distribution of hypocentres and of seismotectonically active zones is used to reconstruct probable displacements and the structural style of deformation in depth the earthquake sources in the vicinity of the medvednica fault and the periadriatic drava fault are given special attention

revised and synthetic apparent polar wander paths of the african eurasian north american and indian plates and true polar wander since 200 ma we have reviewed paleomagnetic data available for the eurasian african north american and indian plates over the last 200 ma selection criteria are those generally accepted with an emphasis on evidence for lack of remagnetization accurate dating and proper structural analysis this results in 23 35 51 and 2 poles for eurasia africa north america and india respectively we believe that this limited set of higher quality data is more likely to reveal key features of apparent polar wander apw paths than averaging of larger data sets involving less stringent selection criteria we propose and describe revised apw paths but more importantly we next use relative motion models to transfer all data in a common reference frame we find good agreement between transferred data when they are averaged separately for each plate in independent 20 ma windows this is a check on consistency of paleomagnetic data kinematic models and of the geocentric dipole hypothesis transferred data from all plates are averaged in 20 ma windows to generate synthetic apw paths for all plates studied these synthetic paths are in agreement with the original revised apw paths that use only data from a single plate moreover both geographic and time resolution are improved spatial confidence intervals are of the order of 5 the synthetic paths display interesting features such as a previously ill recognized apw loop for eurasia paleomagnetic and hotspot apw are next compared and a determination of true polar wander tpw is derived we find significant tpw amounting to over 20 in the last 200 ma tpw appears to be episodic with a standstill between 180 and 110 ma there is general agreement with a previous study of livermore et al 1984 the tpw standstill appears to correlate with a time of decreasing reversal frequency ending with the cretaceous long normal superchron other periods of fast tpw would seem to correspond to increasing reversal frequency however it is suggested that the major tpw hairpin at 50 ma might correspond to the collision of india with eurasia tentative correlations with core or mantle indicators can be understood as a result of couplings between the core mantle and lithosphere we believe primarily related to episodic evolution of the d layer

combination of palaeomagnetic and stress data a case study from north hungary abstract the paper presents the results of a combined palaeomagnetic and microtectonic study in north hungary it analyses the relationship between palaeomagnetically indicated rotations and stress axes at both site and regional level as a result appropriate palaeomagnetic corrections are determined for different sets of microtectonic structures the orientation of the stress axes is restored to its original position by correcting for mass rotation as it is manifested in declination deviation from the present north this process eliminates the apparent rotation of the stress field during the early miocene however our investigations show that real change in orientation of stress axes about 20 did occur during the middle miocene the reconstructed stress field is in good agreement with kinematic models which suggest eastward escape of the area as part of the north pannonian block our results may be best interpreted by attributing the palaeomagnetically indicated rotations partly to rotation of the whole area as a relatively rigid body and partly to local block rotations

reflected sediment gravity flows and their deposits in flysch of middle dalmatia yugoslavia the eocene flysch of middle dalmatia comprises several beds that are interpreted to have been deposited from reflected sediment gravity flows their compositions are similar and two bed types are differentiated complex beds that are debrite plus turbidite couplets and turbidites the sequence alternations in the turbidite part of the bed opposing ripples within the same bed and opposite flow directions indicated by flutes and ripples are indicative of flow reflections the influence of seiches is suggested by the occurrence of symmetrical oscillation ripples the palaeotransport directions of reflected flows show wide dispersal a geometry of small fault controlled sub basins with centripetal palaeotransport patterns is proposed

palaeomagnetic evidence for tertiary counterclockwise rotation of adria abstract with the aim of obtaining tertiary palaeomagnetic directions for the adriatic foreland of the dinaric nappe system we carried out a palaeomagnetic study on platform carbonates from stable istria from the northwestern and the central dalmatia segment of imbricated adria despite the weak to very weak natural remanences of these rocks we obtained tectonically useful palaeomagnetic directions for 25 sites from 20 localities all exhibit westerly declinations both before and after tilt correction concerning the age of the magnetizations we conclude that five subhorizontal and magnetite bearing eocene localities from stable istria are likely to carry primary remanence whereas three tilted and hematite bearing ones were remagnetized in the northwestern segment of imbricated adria the cluster of the mean directions improved after tectonic correction indicating pre tilting magnetization in contrast maastrichtian eocene platform carbonates from central dalmatian were remagnetized in connection with the late eocene oligocene deformation or miocene hydrocarbon migration based on the appropriate site locality means we calculate mean palaeomagnetic directions for the above three areas and suggest an alternative interpretation of the data of kissel et al j geophys res 100 1995 14999 for the flysch of central dalmatia the four area mean direction define a regional palaeomagnetic direction of dec 336 inc 52 k 107 95 9 from these data we conclude that stable istria in close coordination with imbricated adria must have rotated by 30 counterclockwise in the tertiary relative to africa and stable europe we suggest that the latest miocene early pliocene counterclockwise rotations observed in northwestern croatia and northeastern slovenia were driven by that of the adriatic foreland i e the rotation of the latter took place between 6 and 4 ma

in the wake of a counterclockwise rotating adriatic microplate neogene paleomagnetic results from northern croatia in northern croatia the neogene sediments cover complicated basement rocks which consist of alpine and dinaridic elements in the zagorje area and variscan alpine formations of the tisia tisza megatectonic unit in the slavonian mountains mts the neogene sediments were deposited in two separate basins before the karpatian but sedimentation became uniform from the karpatian onwards 17 5 ma of the 24 localities that we have studied so far paleomagnetically from northern croatia 16 localities are of karpatian or younger age while the rest are pre karpatian

deformation partitioning during polyphase oblique convergence in the karawanken mountains southeastern alps abstract the karawanken mountains of southeastern austria straddle the insubric line a major fault zone that corresponds to the austroalpine south alpine border of the eastern alps they display polyphase structural patterns that resulted from deformation partitioning at shallow crustal levels following a poorly constrained late cretaceous deformation history paleogene contraction produced nw se trending fold thrust structures and possibly related sinistral cross faults miocene deformation produced both nw and se directed thrust faults and nw striking high angle dextral cross faults which merged with or displaced the w striking insubric line distributed dextral strike slip displacements of the order of 30 40 km and thrust displacement of 4 5 km along the northern karawanken front initiated subsidence of a small foreland basin north of the karawanken mountains recent regional deformation seems to be concentrated along cross cutting nnw striking dextral faults within a shifting system of seismogenic transfer faults that probably merge with the convergent south alpine thrust front to the west there are conspicuous parallels in the style of deformation along the karawanken mountains with that found along other seismogenic convergent strike slip faults such as those of southern california new zealand and anatolia

the mid hungarian line a zone of repeated tectonic inversions abstract the mid hungarian line is a major tectonic feature of the intra carpathian area separating two terranes of different origin and tectonic structure although this tectonic line was known from borehole records it has not been described in seismic sections the study presents interpreted seismic lines crossing the supposed trace of the mid hungarian line these seismic sections show north dipping normal faults and thrust faults as well as cross cutting young strike slip faults a complex tectonic history is deduced including intra oligocene early miocene thrusting middle miocene extension local late miocene inversion and late miocene pliocene normal faulting and left lateral wrenching in the light of our seismic study we think that the best candidate for the mid hungarian line is a north dipping detachment fault beneath large masses of neogene volcanics the auxiliary structures to the north seen on seismic sections suggest that it moved as a south vergent thrust fault during the palaeogene early miocene which later was reactivated as a set of normal faults the northern alcapa unit overrode the southern tisza dacia unit along this fault zone the same relative positions are observed in the northern termination of the line other structures along the supposed trace of the line are north dipping normal or strike slip faults which frequently were reactivated as smaller thrust faults during the late neogene palaeogene early miocene thrusting along the line might be the result of the opposite tertiary rotations of the two major units as suggested by palaeomagnetic measurements and earlier models

significance of late permian triassic facies zones in terrane reconstructions in the alpine north pannonian domain abstract the present day setting of the tectonic units terranes making up the pre neogene basement of the pannonian basin and the west carpathians is the result of large scale displacements during the alpine collisional phases to explain this setting based on various concepts a number of models have been proposed in the last decade most of them agree in an eastward escape of the north pannonian terrane from the alpine domain towards the pannonian during the palaeogene early miocene period in the present paper a reconstruction of the pre escape setting of the displaced terranes is presented based on facies zones in selected time slices from the late permian to the late triassic according to our reconstruction the inner west carpathian units were located east of the austroalpine units forming the northern shelf of the euhallstatt meliatic basin of the vardar oceanic branch the drauzug should have been located in a position much more external than its present day setting the transdanubian range was situated in the northern neighbourhood of the southern alps whereas the bukk may have been located adjacent to the nw dinarides the mid transdanubian zone is a major shear zone containing elements of the julian alps and sava folds nappe system and the inner dinaric ophiolitic melange although the nappe tectonism may have played an important role in the structural evolution of the north pannonian terrane this mechanism alone can hardly produce hundreds of kilometres of facies offset on the opposite sides of strike slip zones

evolution of the adriatic carbonate platform palaeogeography main events and depositional dynamics abstract the adriatic carbonate platform adcp is one of the largest mesozoic carbonate platforms of the perimediterranean region its deposits comprise a major part of the entire carbonate succession of the croatian karst external or outer dinarides which is very thick in places more than 8000 m and ranges in age from the middle permian or even upper carboniferous to the eocene however only deposits ranging from the top of the lower jurassic toarcian to the top of the cretaceous can be attributed to the adcp defined as an isolated palaeogeographical entity although the entire carbonate succession of the karst dinarides was deposited within carbonate platform environments there were different types of carbonate platforms located in different palaeogeographical settings carboniferous to middle triassic mixed siliciclastic carbonate deposits were accumulated along the gondwanian margin on a spacious epeiric carbonate platform after tectonic activity culminating by regional middle triassic volcanism recorded throughout adria the african promontory a huge isolated carbonate southern tethyan megaplatform abbreviated as stm was formed with the area of the future adcp located in its inner part tectonic disintegration of the megaplatform during the middle to late early jurassic resulted in the establishment of several carbonate platforms including the adriatic apenninic and apulian separated by newly drowned deeper marine areas including the adriatic basin as a connection between the ionian and belluno basins lagonero basin and the area of the slovenian and bosnian troughs the adcp was characterised by predominantly shallow marine deposition although short or long periods of emergence were numerous as a consequence of the interaction of synsedimentary tectonics and eustatic changes also several events of temporary platform drowning were recorded especially in the late cretaceous when synsedimentary tectonics became stronger leading up to the final disintegration of the adcp the thickness of deposits formed during the 125 my of the adcp s existence is variable between 3500 and 5000 m the end of adcp deposition was marked by regional emergence between the cretaceous and the palaeogene deposition during the palaeogene was mainly controlled by intense synsedimentary tectonic deformation of the former platform area some carbonates mostly eocene in age were deposited on irregular ramp type carbonate platforms surrounding newly formed flysch basins and the final uplift of the dinarides reached its maximum in the oligocene miocene the adriatic carbonate platform represents a part although a relatively large and well preserved one of the broader shallow water carbonate platform that extended from ne italy to turkey although its continuity is somewhat debatable in the area near albanian greece boundary this large carbonate body which was deformed mostly in the cenozoic including a significant reduction of its width needs a specific name and the central mediterranean carbonate platform is proposed abbreviated to cmcp although the local names such as adcp for its nw part should be kept to enable easier communication and to facilitate description of local differences in platform evolution

reconciling plate tectonic reconstructions of alpine tethys with the geological geophysical record of spreading and subduction in the alps article a new reconstruction of alpine tethys combines plate kinematic modelling with a wealth of geological data and seismic tomography to shed light on its evolution from sea floor spreading through subduction to collision in the alps unlike previous models which relate the fate of alpine tethys solely to relative motions of africa iberia and europe during opening of the atlantic our reconstruction additionally invokes independent microplates whose motions are constrained primarily by the geological record the motions of these microplates adria iberia alcapia alkapecia and tiszia relative to both africa and europe during late cretaceous to cenozoic time involved the subduction of remnant tethyan basins during the following three stages that are characterized by contrasting plate motions and driving forces 1 131 84 ma intra oceanic subduction of the ligurian part of alpine tethys attached to iberia coincided with eo alpine orogenesis in the alcapia microplate north of africa these events were triggered primarily by foundering of the older 170 131 ma neotethyan subduction slab along the ne margin of the composite african adriatic plate subduction was linked by a sinistral transform system to e w opening of the valais part of alpine tethys 2 84 35 ma subduction of primarily the piemont and valais parts of alpine tethys which were then attached to the european plate beneath the overriding african and later adriatic plates nw translation of adria with respect to africa was accommodated primarily by slow widening of the ionian sea 3 35 ma recent rollback subduction of the ligurian part of alpine tethys coincided with western alpine orogenesis and involved the formation of the gibraltar and calabrian arcs rapid subduction and arc formation were driven primarily by the pull of the gravitationally unstable retreating adriatic and african slabs during slow convergence of africa and europe the upper european iberian plate stretched to accommodate this slab retreat in a very mobile fashion while the continental core of the adriatic microplate acted as a rigid indenter within the alpine collisional zone the subducted lithosphere in this reconstruction can be correlated with slab material imaged by seismic tomography beneath the alps and apennines as well as beneath parts of the pannonian basin the adriatic sea the ligurian sea and the western mediterranean the predicted amount of subducted lithosphere exceeds the estimated volume of slab material residing at depth by some 10 30 indicating that parts of slabs may be superposed within the mantle transition zone and or that some of this subducted lithosphere became seismically transparent

current strain regime in the western alps from continuous global positioning system measurements 1996 2001 four to six years of continuous measurements at 10 permanent global positioning system sites in the western alps show horizontal residual velocities of 2 mm yr with respect to stable europe uncertainties range from 0 3 to 1 4 mm yr these velocities and the associated strain rate field indicate that the central part of the range is currently dominated by east west extension whereas the southern part shows north south to northwest southeast compression the geodetic and seismotectonic data are consistent with a model where strain is essentially controlled by the counterclockwise rotation of the adriatic microplate with respect to eurasia this rotation together with the arcuate shape of the contact between the adriatic microplate and the alps induces dextral shear kinematic boundary conditions across the western alps with an additional divergence component in their central part and in switzerland and a convergence component in their southern part

the role of subduction accretion processes in the tectonic evolution of the mesozoic tethys in serbia abstract ophiolitic rocks and melange occur in two belts in serbia to the northeast the vardar zone and to the southwest the dinaride ophiolite belt of the drina ivanjica belt which is interpreted as being a microcontinent rifted from apulia the tethys in the vardar zone has a long and complex palaeozoic early tertiary history that is still poorly understood ophiolitic rocks are known to have formed at least in the early late jurassic some of the extrusives apparently formed in a supra subduction zone setting based on immobile element geochemical evidence the mesozoic tethys in the vardar zone closed at least partly by the latest jurassic evidence from the apulian margin in the southwest and from the drina ivanjica belt further to the northeast shows that a small red sea type oceanic basin rifted in the late permian early triassic followed by spreading in the mid late triassic to early jurassic evidence from immobile trace elements shows that these extrusives are of mid ocean ridge and within plate type during the early late jurassic this southerly oceanic strand began to close creating melange as a classic subduction accretion complex morb and seamount type lavas channelised micaceous turbidites rare calciturbidites and large limestone masses capped by condensed successions were incorporated in the melange through tectonic processes many of these units originated at or near the southwestern margin of the drina ivanjica inferred microcontinent less deformed debris flows olistostromes reflect gravity reworking and or diapirism with accumulation mainly in perched basins above the subduction zone large overriding harzburgitic ophiolite thrust sheets may have developed in response to incipient spreading above a subduction zone dipping to the southwest these ophiolites were emplaced northeastwards complete with metamorphic soles in response to collision of the trench with the drina ivanjica belt southwest directed sliding of sediments into the foredeep took place prior to suturing in the tithonian and later transgression by clastic sediments

evidence for variable upper mantle temperature and crustal thickness in and near the australian antarctic discordance abstract the southeast indian ridge seir in and near the australian antarctic discordance aad exhibits at a constant spreading rate almost the full range of the many geophysical and geochemical parameters characteristic of the slow mid atlantic ridge and fast east pacific rise we used satellite derived gravity data in combination with seamarc ii bathymetry in and near the aad to examine regional density variations in the upper mantle beneath the aad through three dimensional gravity analysis we found that at least two end member models satisfy the gravity observations regional crustal thickness variations of at least 3 km along the seir near the aad or a temperature anomaly of the order of 150 c in the upper mantle beneath the seir these new observations combined with other geophysical and geochemical characteristics of the australian antarctic discordance provide further evidence that the temperature structure of a mid ocean ridge is a controlling factor in addition to spreading rate in the crustal accretionary process numerical models of mantle flow beneath mid ocean ridges offer one means of investigating the dynamic effect of a variable upper mantle temperature on the accretionary process our results indicate that temperature is important especially at intermediate and slower spreading rates where thermal effects can dominate mantle flow beneath a mid ocean ridge and result in increasing crustal production with decreasing spreading rate at the constant intermediate spreading rate of 37 mm yr characteristic of the seir in and near the aad our numerical models show that significant crustal thinning 2 4 km can occur with relatively small variations in upper mantle temperature all else being equal thus combined with our end member gravity models these observations and results suggest that both anomalously cool upper mantle and thin crust exist beneath the aad

the palaeogene forearc basin of the eastern alps and western carpathians subduction erosion and basin evolution scarce palaeogene sediment remnants in the eastern alps and western carpathians are interpreted as remains of a continuous forearc basin new apatite fission track geochronological data corroborate mild paleocene eocene exhumation and relief formation in the eastern alps palinspastic restoration and nine palaeogeographical maps of the eastern alps and western carpathians ranging from the paleocene to the late oligocene epoch illustrate west to east migration of subsidence in the forearc basin subsidence isochrons indicate that oblique subduction of the european plate below the adriatic plate was responsible for forearc basin migration at a rate of 8 mm a 1 the periadriatic lineament was formed as a result of shearing by oblique subduction the neogene to recent sumatra forearc basin is an analogue for the evolution of the east alpine west carpathian forearc basin

tectonic evolution of the northwestern internal dinarides as constrained by structures and rotation of medvednica mountains north croatia this paper attempts to explain the tectonic history and the possible reasons for the change of trend of the northwestern part of internal dinarides in a transitional area between the southern eastern alps central dinarides and tisia north of zagreb structural and palaeomagnetic data collected in pre neogene rocks at medvednica mts combined with palaeomagnetic data available form neogene rocks in the surrounding area point to the following conclusions 1 the reason for dramatic deflection in structural trend of the internal dinarides in the area north of zagreb is a 130o clockwise rotation and eastward escape of a tectonic block comprising medvednica mts and the surrounding inselbergs bounded to the north by the easternmost tip of the periadratic lineament in medvednica mts the main period of tectonic escape and associated clockwise rotation occurred in late palaeogene possibly in oligocene earliest miocene 2 when rotated into the original position the trend of observed pre neogene structures of medvednica mt becomes parallel to the major structural trend of the central dinarides in view of their original orientation these structures are interpreted in the following way a the first d1 deformational event is attributed to the aptian albian nappe stacking in the central northern dinarides that was accommodated by a top to the north directed shearing and northward propagation of already obducted ophiolites of the central dinaridic ophiolite zone this nappe stacking which resulted in a weak regional metamorphism in tectonic units underlying the ophiolites was orogen parallel or at a very acute angle to known structural and possibly palaeogeographic trends this implies a major left lateral shear component along the former adriatic margin and obducted dinaridic ophiolite zone b this was followed by early albian orogen perpendicular shortening d2 that was accommodated by folding and top to the west thrusting this deformation resulted in gradual cooling of the metamorphic stack and also in uplift and erosion of the higher structural units c d3 deformational event was driven by renewed e w shortening that took place after the paleocene most probably during the middle eocene oligocene i e synchronous with the main dinaridic tectonic phase of the external dinarides this shortening was probably triggered by collision and thrusting of tisia over the northern segment of the internal dinarides d this was finally followed by d4 pervasive right lateral n s shearing that is tentatively interpreted as being related to the right lateral shearing of the sava zone during the eocene oligocene e following the main period of tectonic escape and induced clockwise rotation in late palaeogene possibly in oligocene earliest miocene the medvednica mts and the surrounding area were affected by repeated extensions and inversions since the early miocene to recent times palaeomagnetic data suggest that in the early miocene but probably before the karpatian this area was part of a regional block that shifted northwards and rotated in counter clockwise sense a second episode of counter clockwise rotation occurred at the present latitude in post pontian times since ca 5 ma driven by the counter clockwise rotating adriatic plate

balancing cross sections with kinematic constraints the dolomites northern italy balancing of structural cross sections is often hindered by a limited database or tectonic complications in such cases kinematic constraints may help to better constrain the construction of a cross section and its extrapolation to depth the kinematic implications of a known structure generally at the surface have to be considered for the unknown structure and for the internal consistency of a cross section a key point is the quantification of shortening of the known structure the extrapolation of this parameter allows balancing in an approximate way emphasizing major structures while minor structures are either neglected or treated in a simplified way with this approach a quick overview can be achieved on how much leeway for interpretation exists critical points for testing various working hypotheses become more evident and the trial and error effort during the construction of a balanced section is considerably shortened still the implications the observed structures have on the deeper crustal levels can be assessed this concept is applied to a section across the italian dolomites a brittle fold and thrust belt lacking reflection seismic data so far and thus with a poorly known deep structure still active south vergent alpine thrusting is oriented approximately perpendicular to previous dinaric thrusting the ramp flat style is dominant due to rheological constrasts within the stratigraphic sequence thanks to kinematic balancing based on surface data three alpine thrust systems could be identified each defining a thrust sheet with its particular basement unit and its sedimentary part superposition of the two more external basement units led to the presently observed high elevation of the triassic sequence in the dolomites shortening since late miocene times amounts to more than 50 km retrodeformation of alpine thrusting is a key for better understanding the previous dinaric structures and kinematics

geochemical modeling of coal mine drainage summit county ohio geochemical modeling was used to investigate downstream changes in coal mine drainage at silver creek metro park summit county ohio a simple mixing model identified the components that are undergoing conservative transport cl po43 ca2 k mg2 and na and those undergoing reactive transport do hco3 so42 fe2 mn2 and si fe2 is removed by precipitation of amorphous iron hydroxide mn2 are removed along with fe2 by adsorption onto surfaces of iron hydroxides do increases downstream due to absorption from the atmosphere the hco3 concentration increases downstream as a result of oxidation of organic material the rate of fe2 removal from the mine drainage was estimated from the linear relationship between fe 2 concentration and downstream distance to be 0 126 mg s results of this study can be used to improve the design of aerobic wetlands used to treat acid mine drainage