lithospheric dynamics and tectonic stratigraphic evolution of the ebro basin we present analysis of two dimensional modeling of the tectonic subsidence in the ebro basin along three profiles crossing the pyrenees the ebro basin and the catalan coastal range to the east and the iberic cordillera to the west the deformation of the foreland basin during tertiary times is simulated using a lithospheric flexure model incorporating laterally varying elastic thicknesses the deflection of the plate is the combined result of pyrenean loading and the loads exerted by the iberic cordillera and catalan coastal range in the eastern part of the ebro basin no extra driving force on the iberian plate is required the flexural modeling supports the hypothesis that underplating of the iberian plate under the european plate is not associated with subduction of old oceanic lithosphere a good fit with the tertiary basin subsidence data and bouguer anomalies is obtained for an elastic plate with local weakness zones under the ebro basin the inferred lateral variation in the elastic rigidity is consistent with heat flow measurements in northern spain and with major mesozoic extension in the iberic cordillera and valencia trough

effet de la vitesse de refroidissement sur l intensite de l aimantation thermoremanente etude experimentale consequences theoriques the experiments reported here compare intensity and thermal resistance of two thermal remanent magnetizations trm successively acquired by the same sample under a magnetic field but at two different cooling speeds the samples one with a base of cro2 powder and the others derived from oceanic basalts were representative of the different types of structure domains characteristic of magnetic grains the experimental procedure established aimed at limiting the various factors of uncertainty mineralogical and structural modifications related to heating inhomogeneity of the sample temperature at crucial stages of each experiment effects of undesirable magnetizations acquired concurrently with the trm the main conclusion of this study is that the trm intensity increases as a function of time of cooling independently of the types of structure domains carried by the magnetic grains the greatest effect is with the cro2 monodomain the trm obtained between 130 and 100 c during a cooling period of 120

eddies in the labrador sea as observed by profiling rafos floats and remote sensing abstract data from profiling rafos floats topex poseidon altimetry and the alongtrack scanning radiometer atsr aboard ers 1 have been used to describe the spatial and seasonal patterns of eddy variability in the labrador sea peaks in sea surface height ssh variability appear in two regions off the west greenland shelf near 61 5 n 52 w where the 3000 m isobath separates from the shelf and in the center of the basin at 58 n 52 w both locations show seasonal ranges in ssh variability of up to 40 mm with the greenland site having largest variability in january march leading the central site by 50 days a sea surface temperature image from the atsr at the greenland site shows numerous eddies both cyclonic and anticyclonic being formed by injection of west greenland current water into the labrador sea interior data from profiling rafos floats launched in 1997 as part of the labrador sea deep convection experiment are used to describe three of the west greenland current eddies in detail one of

low frequency 3 d seismic survey of upper crustal magmatic intrusions in the northeastern pannonian basin of hungary abstract a specially designed 700 km2 grid survey deploying 1000 regularly distributed low frequency seismic recording systems successfully investigated one of the most complex geologic environments of the pannonian basin the wide angle signals penetrated through over 1000 m of multi phase igneous lithology and recognized for the first time the underlying enigmatic permian to early triassic basement rocks tomographic inversion of the first arrival grid data resulted in determination of an accurate three dimensional 3 d velocity field to a depth of 4 km the anomalous changes of the spatial velocity data outline the regional extent of the late miocene magmatic intrusions which are covered by over 2000 m of mid miocene to pleistocene clastics complex relationship was found between the surface potential data and the intrusive bodies this multi faceted geophysical data analysis established a functional technique for mapping a subsurface with intricate acoustic and structural complexity

the variation of heat generation density and seismic velocity with rock type in the continental lithosphere abstract the petrophysical properties radioactive heat generation compressional wave velocity and density are related to rock type in crystalline rocks the cation fraction in the rock forming minerals is applied to determine the relationships quantitatively heat generation exhibits considerable variation with rock type as well as with the geologic age of the rocks therefore the relation between heat generation and rock type has been split into a relation for phanerozoic rocks and another for precambrian rocks which exhibit significantly lower heat generation only 1 3 of that of phanerozoic rocks the interrelations between the petrophysical properties are applied to fennoscandia precambrian terrane and southern bavaria northern alpine foreland phanerozoic rocks to estimate the heat generation by radioactivity in the crust and the heat flow density from the upper mantle

the evolution of the carpathians pannonian system interaction between neotectonics deep structure polyphase orogeny and sedimentary basins in a source to sink natural laboratory abstract the carpathians pannonian basin system provides a natural laboratory for analysing lithospheric to surface controls on tectonic topography development in a coupled source to sink environment to link processes taking place at depth and at the surface recent research focused on the interplay between basin evolution active tectonics topography evolution and intraplate folding mechanisms neotectonic processes control landscape development and natural hazards in particular the seismicity during the late stage late neogene quaternary evolution of both the carpathians pannonian basin system and its interaction with the adjacent dinarides and balkans the deep structure of the se carpathians exerts a strong control on the post collisional evolution of the system new constraints are available from seismic tomography deep seismic reflection and refraction profiling and detailed studies of the vreancea seismicity inherited orogenic fabric and structure of the active black sea sink has a strong influence on the localisation of the neogene sediment pathways a close relationship has been established between the timing and mechanisms of stress changes in the pannonian and transylvania basins and structural episodes in the surrounding thrust belts pointing to an intrinsic mechanical coupling with these basins the orogen and its foredeep basin inversion taking place during the pliocene quaternary times in the entire carpathians pannonian system is related to changes in the regional stress field leading to differential vertical movements associated with a laterally variable folding mechanism active in the entire system short crustal folding patterns alternate with lithospheric wavelengths in the se carpathians foreland east and south carpathians transylvania and pannonian basins the lateral variability is the result of a marked contrast in rheology between these areas directly related to the crustal configuration thermal properties and late stage collision kinematics with the carpathians foreland lateral variations in the properties of the downgoing plates largely control the collision mode in the carpathians and the post collisional evolution of the entire system

the identification of mantle reflections below hungary from deep seismic profiling abstract in the 1970 s the eotvos lorand geophysical institute performed seismic reflection deep sounding experiments with multiple coverage in several parts of the pannonian basin posgay 1975 one of the most interesting results was that arrivals were received in the time range corresponding to the depth of the asthenosphere they were interpreted as reflections posgay et al 1981 conspicuous arrivals from the time range of the asthenosphere 15 20 s were also received along the pannonian geotraverse in 1987 in the majority of sections published in other countries the upper mantle seems to be transparent the present paper discusses investigations and preliminary results which lead to the conclusion that this apparent transparency is due to the frequency range below 10 hz being neglected in both signal generation and recording in most deep continental reflection surveys the seismogeological conditions of the pannonian basin are certainly favourable for reflection studies of the upper mantle the correctness of the assumption that arrivals from the time range of the asthenosphere are primary reflections is subjected to further investigation and conclusions are made concerning the structure of the asthenosphere

crustal structure of the carpathian pannonian region from ambient noise tomography we use ambient noise tomography to investigate the crust and uppermost mantle structure beneath the carpathian pannonian region of central europe over 7500 rayleigh wave empirical green s functions are derived from interstation cross correlations of vertical component ambient seismic noise recordings 2005 2011 using a temporary network of 54 stations deployed during the south carpathian project 2009 2011 56 temporary stations deployed in the carpathian basins project 2005 2007 and 100 permanent and regional broad band stations rayleigh wave group velocity dispersion curves 4 40 s are determined using the multiple filter analysis technique group velocity maps are computed on a grid of 0 2 0 2 from a non linear 2 d tomographic inversion using the subspace method we then inverted the group velocity maps for the 3 d shear wave velocity structure of the crust and uppermost mantle beneath the region our shear wave velocity model provides a uniquely complete and relatively high resolution view of the crustal structure in the carpathian pannonian region which in general is validated by comparison with previous studies using other methods to probe the crustal structure at shallow depths 30 km are relatively fast presumably related to shallowing of the moho consequent on the extensional history of the pannonian region

gravity modelling of the lithosphere in the eastern alpine western carpathian pannonian basin region abstract gravity models illustrate changes in the degree of continental convergence in the eastern alpine western carpathian region and modifications to the lithosphere due to the plate convergence and subsequent pannonian basin extension analysis of the continental collision zone incorporates a kinematic model of ocean basin closure whereby gravity anomalies and topography are viewed as part of a continuum of continental crustal shortening erosion and isostatic rebound thick crust and high topography in the eastern alps along with a broad bouguer anomaly of 140 mgal amplitude are consistent with about 175 km of crustal shortening followed by 10 km of isostatic rebound eastward crustal thicknesses and gravity anomaly widths and amplitudes are less so that only about 50 km of continental crustal shortening and 4 km of rebound occurred in the western carpathians preservation of thick flysch deposits and small isostatic rebound are attributable to the high density shallow mantle of the intact continent ocean transition zone seismic delay time studies have suggested that relative to the average thickness of the region the lithosphere thickens by about 70 km beneath the eastern alps and thins by about 60 km under the pannonian basin in both regions gravity anomalies cannot be explained fully without considering this large relief on the lithosphere asthenosphere boundary the eastern alpine crustal root which extends 15 km below the average depth for the region overcompensates the topography and results in gravity anomalies that are 40 mgal lower than those observed the extra 70 km of lithosphere provides excess mass that achieves isostatic equilibrium and accounts for the 40 mgal difference observed gravity anomalies and local isostasy are also consistent with thin crust and thin lithosphere beneath the pannonian basin whereby the 60 km of extra asthenosphere provides a large part of the compensation for the elevated mantle regional cross sections suggest that shallowing of the lithosphere asthenosphere boundary associated with pannonian basin extension has propagated northward beyond the carpathians to within the european platform crustal thinning however appears to be confined to exotic terranes of the carpathian interior so that crustal structure in the eastern alps and outer carpathians is a remnant of the earlier collision orogen

lateral extrusion in the eastern alps part 1 boundary conditions and experiments scaled for gravity lateral extrusion encompasses extensional collapse gravitational spreading away from a topographic high in an orogenic belt and tectonic escape plane strain horizontal motion of wedges driven by forces applied to their boundaries in the eastern alps it resulted from 1 an overall northerly compression apulia against eurasia 2 a strong foreland bohemian massif 3 lack of constraint along a lateral boundary carpathian region and 4 a previously thickened gravitationally unstable thermally weakened crust eastern alpine orogenic belt six indentation experiments reproduce lateral extrusion at lithospheric scale the models have two to four lithospheric layers with a mohr coulomb rheology for the upper and a viscous rheology for the lower crust the lithosphere rests upon a low viscosity asthenosphere a broad indenter a narrow deformable area and a weakly constrained eastern margin fullfill as closely as possible conditions in the eastern alps indentation produces both thickening in front of the indenter and escape of triangular wedges lateral variations in crustal thickness become attenuated by gravitational spreading the overall fault pattern includes domains of reverse strike slip oblique normal and pure normal faults strike slip faults in conjugate sets develop serially the narrow width of the deformable area and the strength of the foreland determine the angles between the sets gravitational spreading produces a rhombohedral pattern of oblique and pure normal faults along the unconstrained margin opposite the unconstrained margin the indenter front shows thrusts and folds intersecting with the conjugate strike slip sets a triangular indenter favors spreading high velocity of indentation favors escape high confinement limits lateral motion inhibits spreading and favors thickening lateral extrusion in the eastern alps is best modeled by 1 a weak lateral confinement 2 a broad and straight indenter 3 a narrow width of the deformable area and 4 a rigid foreland crustal thickening lateral escape and gravitational spreading all contribute to the overall deformation

the nature and genesis of gold silver tellurium mineralization in the metaliferi mountains of western romania precious metal au ag and base metal pb zn deposits in the metaliferi mountains of western romania occur in steeply clipping quartz ca mn carbonate veins which are hosted by miocene andesitic stocks and lava flows and surrounding sedimentary rocks the deposits consist predominantly of sulfides pyrite chalcopyrite sphalerite galena sulfosalts of as and sb and a diverse range of au ag tellurides the igneous host rocks have undergone mild pervasive propylitic alteration whereas immediately adjacent to the veins the wall rock alteration assemblages consist of quartz sericite k feldspar calcite and pyrite fluid inclusion stable isotope and thermodynamic data suggest that the majority of the mineralization and hydrothermal alteration in these deposits was caused by loci salinity 0 5 wt nacl equiv medium temperature 200 degrees 300 degrees c near neutral ph 5 6 fluids which underwent occasional boiling the fluid inclusion and stable isotope data support a model in which a metal bearing magmatic fluid was exsolved from a crystallizing calc alkaline melt and ascended to higher levels in the crust undergoing some isotopic exchange with surrounding sedimentary rocks but limited mixing with ground waters although the deposits in this part of the romanian carpathians exhibit many of the geologic characteristics of classic low sulfidation volcanic hosted au ag epithermal deposits they seem to have formed from essentially magmatic waters and there is little evidence for the incorporation of meteoric fluids into the hydrothermal system

lateral variations in lithosphere strength in the romanian carpathians constraints on basin evolution lithospheric strength profiles constructed through extrapolation of rock mechanics data and constrained by crustal geophysics data demonstrate the existence of important spatial variations of thermomechanical properties in different domains of the romanian carpathians the pannonian basin and the transylvanian depression these models show important lateral variations in lithospheric rigidity along the southern and eastern carpathian foreland compatible with inferences from flexural modelling studies the modelling predicts an absence of mantle strength and the presence of weak lithosphere in the pannonian and transylvanian basins a nw se trending rheological transect is presented connecting the moesian platform the vrancea region of the carpathians the transylvanian basin and the apuseni mountains with the romanian part of the pannonian basin this transect demonstrates the existence of a close correlation of the inferred spatial variations in mechanical properties of the romanian lithosphere with observed patterns in large scale gravity anomalies and with tectonic units a notable feature of the rheological models is the presence of an intra carpathian weak zone the combination of a strong foreland lithosphere with a weak lithosphere in the inner part of the carpathian transylvanian pannonian system sheds light on a number of key features observed in the evolution of sedimentary basins in these areas remarkable differences in rheology predictions between flexural models and depth dependent rheology models indicate that the crustal lithosphere is detached from the mantle part of the lithosphere in the carpathian foreland

flexural expression of european continental lithosphere under the western outer carpathians we present the results of an analysis of the flexural down bending of the european lithosphere under the western outer carpathians for a grid of five profiles with a lateral spacing of about 100 km crossing the carpathians and its foreland seismic sections including two deep seismic reflection lines and numerous wells allowed us to quantify the flexural curvature of the lithosphere in addition gravity data are used to obtain independent constraints two evolutionary scenarios involving subduction underthrusting of passive margin and a phase change in the lower crust are investigated in a context of relatively flat moho under the area furthermore recent uplift expressing itself in erosional features observed along the distal margin of the foredeep is quantified the generally modest bouguer gravity anomaly points to nonisostatic processes causing this uplift steeply dipping basement under the carpathians to about 10 km depth at the location of the pieniny klippen belt is explained by relatively weak lithosphere which is expressed in the predicted low values of effective elastic thickness of 16 km decreasing locally to 3 km the low strength of the european lithosphere in this region is probably caused by mechanical weakening controlled by partial yielding due to high flexural curvature the weakest parts of the lithosphere along the profiles corresponding to low effective elastic thicknesses are concentrated in the areas of maximum bending predicted flexural bending stresses as a function of bending moment and effective elastic thickness increase dramatically under the outer zone of the carpathian belt explaining reactivations of older basement structures in these regions

crustal structure of the alpine pannonian transition zone a combined seismic and gravity study the crustal structure of the transition zone between the eastern alps and the western part of the pannonian depression danube basin is traditionally interpreted in terms of subvertical tertiary strike slip and normal faults separating different alpine tectonic units reevaluation of approximately 4000 km long hydrocarbon exploration reflection seismic sections and a few deep seismic profiles together with data from approximately 300 wells suggests a different structural model it implies that extensional collapse of the alpine orogene in the middle miocene was controlled by listric normal faults which usually crosscut alpine nappes at shallow levels but at depth merge with overthrust planes separating the different alpine units the alternative structural model was tested along a transect across the danube basin by gravity model calculations and the results show that the model of low angle extensional faulting is indeed viable regarding the whole lithosphere of the western pannonian basin gravity modelling indicates a remarkable asymmetry in the thickness minima of the attenuated crust and upper mantle the approximately 160 km lateral offset between the two minima suggests that during the miocene extension of the pannonian basin detachment of the upper crust from the mantle lithosphere took place along a rheologically weak lower crust

depth of crustal conducting layer and asthenosphere in the pannonian basin determined by magnetotellurics abstract on the basis of numerical modelling and statistical investigations of the horizontal electrical inhomogeneities narrow fractures change of conductance of the surface sediments min magnetotelluric mt sounding curves were found to be less distorted and therefore they can be used for the determination of deep conducting formations in the crust and upper mantle carefully selected mt curves indicate the crustal conductive layer at depths of 7 13 km and the conductive asthenosphere between 50 and 80 km the relatively shallow position of the asthenosphere corresponds to the high heat flow q 80 mw m 1 in the pannonian basin according to the empirical relation derived by adam 1978

towards a mechanical model for the formation of the pannonian basin abstract new maps showing crustal and lithospheric thickness variations in the pannonian basin and the surrounding east alpine carpathian and dinaric mountains have been prepared on the basis of recent seismic seismologic and electromagnetic data a map presenting miocene faults of regional significance has been also constructed for the same region by using a wealth of recently available national and or more local studies it is suggested that observed crustal and lithospheric structural contrasts have been controlled primarily by neogene kinematic history of the region kinematic history is characterized by the following main patterns 1 1 indentation by adria and large scale backthrusting in the southern alps 2 2 eastward escape and extension of the eastern alps 3 3 extensional collapse in the pannonian basin area 4 4 formation of broad wrench fault systems along strike in the dinarides and southern carpathians and the western carpathians with dextral and sinistral shear respectively 5 5 compression and accretion of the external thrust and fold belt in the eastern carpathians these kinematic patterns are thought to be interrelated and all are manifestations of the late stage evolution of an overthickened orogenic wedge in order to arrive at a better understanding of the mechanism of extension which formed the pannonian basin deep crustal seismic profiles hydrocarbon exploration reflection lines and borehole data have been analyzed in the little hungarian plain this plain represents the transition zone between the alps and the pannonian lowlands and the results are illustrated by eight interpreted cross sections one result of regional importance is the clear recognition that the transdanubian central range at the southeastern flank of the little hungarian plain is composed of alpine pre senonian thrust sheets this finding marks the end of a century of debate the allochthony of the substrata of the pannonian basin can be now considered proven another result of more general interest is that these cross sections document the mode of lithospheric extension preexisting compressional detachment planes reactivate as low angle normal faults and lead to tectonic unroofing of deeply buried metamorphic terranes characterized by ductile flow along subhorizontal lineation

bifurcation of a coastal current at an escarpment the evolution of a coastal current as it encounters an escarpment depends strongly on whether the geometry of the coast and escarpment is right or left handed independent of the direction of the coastal current handedness is defined such that right handed means that when looking across the escarpment from the deep to the shallow side the coast is found on the right the essential aspects of the difference in behavior of the current in the two geometries are captured by a simple quasigeostrophic model of coastal flow over a step an exact analytic solution to the nonlinear stationary problem is obtained this solution shows that when a coastal current crosses an escarpment in the left handed geometry the speed of the current will increase independent of whether the flow is from shallow to deep or from deep to shallow for the right handed geometry the speed of the current decreases also independent of the direction of the coastal flow in the left right handed geometry there is associated to the coastal flow an inshore offshore current along the escarpment these results are explained in terms of linear wave theory and vortex dynamics numerical simulations are used to examine the evolution of the flow from the initial encounter to the establishment of a stationary flow the relevance of this research is discussed in light of recent results from laboratory experiments and oceanic observations

a modeling study of coastal trapped wave propagation in the gulf of california part ii response to idealized forcing abstract the evolution of remotely forced coastal trapped waves in the gulf of california is studied using a hydrostatic primitive equation model the sea level time variability at a remote station south of the gulf is assumed to propagate northward into the gulf as a mode 1 coastal trapped wave ctw to validate this assumption observations and model results are compared in general sea level fluctuations are reasonably well represented by the model with model data correlations decreasing from 0 76 at topolobampo close to the entrance of the gulf to 0 52 at santa rosalia in the central gulf model data correlations of velocity are lower 0 6 in the gulf ctws propagate northward along the east side with no significant changes south of the sill which is 600 km north of the entrance when incident waves propagating northward in the gulf along the east side arrive at the sill a small fraction of the wave energy enters the northern gulf and is dissipated most of the wave energy is steered at the

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

cretaceous to miocene thrusting and wrenching along the central south carpathians due to a corner effect during collision and orocline formation field studies in the romanian south carpathians longitude 22 5 to 24 2 e and latitude 45 2 to 45 6 n demonstrate 1 cretaceous top to ne shearing parallel to the present strike of the thrust system connected with coaxial flattening within the generally northwest dipping foliation 2 paleogene ductile brittle dextral wrenching e w compression 1 87 15 and basin formation petrosani basin along the cerna jiu fault system 3 large scale miocene dextral wrenching along the northern margin of moesia 1 143 16 and 4 probably pliocene early pleistocene n s compression 1 205 25 we discuss the tectonics of the south carpathians stressing the corner effect of the moesian foreland promontory during convergence and formation of the carpathian orocline up to the late early cretaceous subduction of oceanic crust was active between europe moesia on one side and east carpathia rhodopia on the other side collision and intracontinental deformation occurred during the late early and late cretaceous the pinning of the thrust front at the western tip of moesia and the foreland recess north of it caused superposition of thrusting and wrenching during collision and lateral translation tangential stretching during orocline formation and spreading into the recess further convergence during the early tertiary resulted in dislocation of the previously welded east carpathian rhodopian and moesian fragments along the cerna jiu fault system and the further northeast translation of the western segment the intramontane petrosani basin opened as a northeasterly propagating transient pull apart structure along the cerna jiu fault system which acquired a curved northwesterly convex transtensional trace due to the shape of the moesian promontory tightening of the carpathian orocline and or rearrangement of the microplate geometry during the formation of the pannonian basin system led to large scale dextral wrenching along the northern margin of moesia pliocene n s compression reflects final shortening in the carpathian system before ongoing convergence between europe and africa was transferred to the mediterranean rotation of material lines around the moesian corner is corroborated by paleomagnetic studies

cooling behaviour of partial thermoremanences induced in multidomain magnetite the cooling behaviour of partial thermoremanences ptrm below the acquisition temperature t is reported for the first time for well defined sized synthetic multidomain magnetite samples produced by hydrothermal recrystallisation the ptrm cooling behaviour of low stress magnetite samples is similar but not identical to that reported for higher stress crushed magnetite samples that is it displays a decrease in ptrm on cooling below t indicating domain re organisation this agrees with recent kinetic theories and domain observations but strongly dis

gravity anomalies and flexure of the lithosphere at mountain ranges the bouguer gravity anomaly over the himalayan alpine and appalachian mountains is characterized by a generally asymmetric gravity low which spans the mountains and associated foreland basins the minimum of the gravity low is generally systematically displaced from the region of greatest topographic relief and shows no obvious relationship to surface geology in addition the alps and appalachians are associated with a generally symmetric gravity high that is unrelated to the topographic relief together the gravity low and high form a characteristic positive negative anomaly couple the steep gravity gradient between the positive and negative couple correlates with the insubric line and its equivalents in the alps and the brevard zone in the southern appalachians this gravity anomaly couple is interpreted as evidence for flexure of the continental lithosphere by subsurface buried and surface topographic loading the magnitude of the subsurface load is estimated from the integrated excess mass represented by the positive anomaly and the magnitude of the surface load from the topography by combining these loads the flexure of the lithosphere and the associated bouguer gravity anomaly are calculated for different assumed values of the elastic thickness te of continental lithosphere the best fitting value of te for the himalayas is 80 100 km for the alps 25 50 km and for the appalachians 80 130 km the model calculations suggest that the main contribution to the gravity couple in the alps and appalachians arises not from surface loads such as thrust sheets and nappes but from subsurface loads however in the case of the himalayas the topography appears to be a sufficient load to explain the observed asymmetric gravity low when subsurface loads do exist therefore we would not expect a close correlation between mountain topographic relief and depth to the m discontinuity as required by classical models of isostasy rather the m discontinuity is expected to relate to the center of mass of all the loads acting on the lithosphere the surface and subsurface loads inferred from the gravity anomaly play a major role in the development of mountains and foreland basins the emplacement of large subsurface loads represents the primary event in the alps and appalachians while in the himalayas the emplacement of the surface load is the primary event the emplacement of the subsurface load probably marks the initiation of foreland basin development the regional characteristics of the basin are controlled by the primary load while local variations are controlled by the secondary thrust sheet loads subsequent movement of either load will produce migration of the basin depocenter the origin of the subsurface load is not clear but its association with the insubric line in the alps and the brevard zone in the appalachians suggests that it may be related to the obduction of crustal blocks flakes onto the underlying plate during continental collision or possibly to the preloaded crustal structure of the underlying plate

the neogene evolution of the outer carpathian flysch units poland ukraine and romania kinematics of a foreland fold and thrust belt system abstract various techniques of geometric and kinematic analyses including cross section balancing and forward modeling have been applied successfully to the outer carpathian flysch units along regional geologic profiles crossing the belt from its undeformed foreland to the pieniny klippen belt western carpathians poland or to the central east carpathian allochthon eastern carpathians ukraine and romania the amounts of neogene shortening as well as the mode and the location of basement consumption are discussed on the basis of balanced cross sections compiled along the three most representative regional traverses in addition the complete kinematic evolution of complex carpathian structures such as the fore dukla triangle zone southeastern poland the borislav pokut duplexes ukraine and the marginal folds romania are described in more detail by using a forward modeling approach major results concern the tectonic heritage of laramian inverted structures mesozoic normal faults reactivated as reverse faults during the late cretaceous paleocene compression or transpression in the development of the neogene outer carpathian edifice pre eocene deformation and erosion effectively induce discontinuities in the mid cretaceous blackshale detachment horizon and help to localize the neogene deformations in complex triangle zones the thrust sequence itself evolves alternatively in a piggyback or in an out of sequence mode clearly the critical taper of the outer carpathians is preserved by a constant balance between erosion and thrust reactivations in the inner part of the wedge and sedimentation and tectonic accretion at its front

main results of the ecors pyrenees profile abstract the 250 km long deep seismic reflection survey across the pyrenees from one foreland ebro basin to the other aquitaine basin was designed to study the structure of the deformed mesozoic boundary between the iberian and european plates the results are 1 1 the entire crust shows well defined reflectors with a general fan shape geometry 2 2 a deep layered domain is evident above the moho discontinuity 3 3 near the surface in the external domains reflectors accurately define the geometry of major thrusts and structures affecting the mesozoic and cenozoic cover of the pyrenees 4 4 the middle crust shows two major sets of seismic events interpreted as hercynian structures using these results a balanced structural section of the pyrenean belt is proposed the mode of thickening of the crust during the alpine orogeny is briefly discussed only the iberian crust was significantly thickened by a southward stacking of slabs

review of neogene and quaternary volcanism of the carpathian pannonian region abstract development of the pannonian basins as well as thrusting and folding of the carpathians was accompanied by widespread volcanic activity this volcanism can be divided into three main genetic types 1 1 early miocene mainly acidic volcanism tuffs and ignimbrites the recent spatial separation of these volcanics may be due to large right lateral displacement along the mid hungarian shear zone during the early miocene 2 2 middle miocene pliocene calc alkaline mainly intermediate stratovolcanic complexes in the inner western carpathians and in the east carpathians related to a subducted oceanic slab their geochemical compositions show a transitional character between active continental margin and island arc type magmatic rocks the thickness of the crust increased with time and from west to east beneath this volcanic arc 3 3 pliocene pleistocene alkali basaltic volcanism was related to an upwelling then cooling asthenospheric dome this is thought to have initiated the thermal regime from which these melts ascended the compositional difference in space and in time might reflect the existence of local individual small sized diapiric bodies as well as several processes e g fractional crystallization mixing which modified the original magma the eruption of these basaltic melts was temporally associated with the final phase of development of the pannonian basin this volcanism was associated with recent uplifts and tectonic rejuvenation of the area

crustal structure in the carpatho pannonian region insights from three dimensional gravity modelling and their geodynamic significance a three dimensional gravity modelling of the carpatho pannonian region was carried out to get a better image of the moho boundary and the most prominent intra crustal density heterogeneities at first only the major density boundaries were considered the bottom of the tertiary basin fill the moho discontinuity and the lithosphere to asthenosphere boundary density contrasts were represented by relative densities the improved density model shows a transitional unit of high density at the base of the crust along the teisseyre tornquist zone in the western carpathians an extensive relatively low density unit was inferred in mid crustal levels the border zone between the southern carpathians and the transylvanian basin is characterized by a sharp step like contact of the two crustal units the moho configuration reveals important information on the tectonic evolution of the region zones of continental collision are represented by thick moho roots eastern alps eastern carpathians transpressional orogenic segments however are different in the western carpathians the moho is a flat surface in the dinarides a medium moho root is observed the southern carpathians are characterized by a thick crustal root the differences are explained with the presence or absence of subductible oceanic crust along the carpathians during the extrusion of pannonian blocks

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

free surface adjustment and topographic waves in coastal currents the adjustment of rotating free surface flow over a step like escarpment abutting a vertical wall is discussed in the context of the shallow water equations the problem is simplified by considering an escarpment of small fractional depth so that on the slow topographic timescale the initial fast poincare and kelvin wave adjustment of the free surface is effectively instantaneous and further simplified by considering the surface displacement to be small compared with the escarpment height so that particle velocities are negligible during the topographic adjustment direct solution of the resulting linear system is not straightforward as arbitrarily small scale motions are generated at sufficiently large times the problem is reduced by a green s function technique to one spatial dimension and the wall boundary layers resolved by introducing a scaling based on previously obtained limit solutions solutions verify the information propagation arguments of johnson 1985 and gill et al 1986 and also show interchange of fluid across the escarpment as eddies formed as the current crosses the step travel along the step with shallow water the pattern of evolution of the system is independent of the direction of the flow depending solely on the sign of the topographic step

classification of rifted sedimentary basins of the pannonian basin system according to the structural genesis evolutionary history and hydrocarbon maturation zones abstract we apply the concept that sedimentary basins can be classified according to their structural genesis and evolutionary history to the tertiary rifts of the pannonian basin of eastern europe we have approached the classification by breaking the basins down into the cycles or stages that they comprise this approach helps us to understand the basin evolution better and allows us to compare the basins more easily the drivers that define the cycles of basin history are 1 basin forming tectonics 2 sedimentary processes and 3 basin modifying tectonics we link common elements of petroleum systems and plays to these natural cycles or stages in basin evolution to improve the prediction of which plays could be expected to occur in a particular basin or region this concept is constructed through several steps these steps are 1 to identify standard evolutionary patterns related to geodynamic drivers 2 to group the basins with similar tectono stratigraphic evolution and correlate these with petroleum system development 3 to relate basin trap types to basin history and 4 to calculate characteristic hydrocarbon maturation zones by thermal modeling we present an application to the pannonian basin system of eastern europe an area formed by miocene back arc extension and affected by compressional reactivation during its late stage evolution the sub basins of the pannonian basin system appear to have experienced comparable magnitudes of deformation to have developed similar trap types and to have experienced a characteristic hydrocarbon maturation history in a way that supports play prospectivity

poleward along shore current pulses on the inner shelf of the bay of biscay abstract we analyzed strong events of coastal poleward along shore currents above 10 cm s 1 and up to more than 50 cm s 1 on the inner shelf 50 80 m depth of the bay of biscay bob from the spanish coast to the brittany coast we used data from four acoustic doppler current profilers adcps deployed from july 2009 to august 2011 the goal of this study was to analyze current variability at meso and subinertial scales and its generation mechanism these currents occurred all year long and were classified into three types events occurring principally in the southern part of the bob were classified as southern events bay scale events were defined when strong poleward currents were detected over all the shelf typically stronger on the spanish and the southern brittany shelves strong events were characterized by depth averaged current velocities over 40 cm s 1 in the southern part of the bob at short time lags the along shore currents were clearly related to along shore wind stress at upstream locations an explanation is provided for longer time lags in terms of coastal trapped wave ctw dynamics the first ctw mode phase speeds were in agreement with the propagation speeds of the fastest events 5 m s 1 while inner shelf modes could explain the slowest events 1 3 m s 1 the cross shelf density gradient and the extension of the ipc were also associated with strong coastal poleward along shore currents the duration of the events the vertical structure of the currents and the associated coastal trapped waves were studied in relation with the stratification

experiments and simulations on coastal flows in the presence of a topographic slope the evolution of a barotropic coastal current in the presence of a bottom ramp shaped topography is studied by means of laboratory experiments and numerical simulations the experiments are performed in a rectangular rotating tank filled with freshwater the fluid depth is shallow at one side of the domain and deeper at the other side and both regions are divided by a narrow slope whose depth contours are perpendicular to the long sides of the tank a current approaching the slope is produced along one of the vertical walls having the boundary at its right two configurations are analyzed when the current flows from shallow to deep water and when flowing in the opposite direction in the first scenario the current is divided in two parts one of them following the coastline the other part of the current pairs with a cell of negative relative vorticity generated at the slope due to squeezing effects forming a dipolar structure moving offshore back toward the shallow side in addition a weak current moving inshore along the slope is clearly formed in the second configuration when the flow goes from deep to shallow water a part of or even the whole current might be forced to move along the contours of the topography away from the coast in this case there is no dipole formation the experiments are well reproduced by means of quasigeostrophic numerical simulations which allow a more detailed systematic study of the influence of flow parameters such as the topography height and the width of the slope

coincident seismic reflection refraction studies of the continental lithosphere a global review nearly 50 coincident seismic reflection refraction studies to depths of at least the moho provide an improved understanding of the continental lithosphere some conclusions include the following 1 a transparent upper crust a common observation on vertical reflection profiles cannot generally be correlated with velocity gradients or low velocity zones rather a commonly transparent upper crust may be explained by short wavelength steeply dipping features in the brittle upper crust and to a lesser degree by signal contamination from source generated noise 2 the reflective lower crust in extensional terranes appears to be characterized by a high average seismic velocity 6 6 7 3 km s and to consist of laminated high and low velocity layers with typical thicknesses of 100 200 m 3 landward dipping reflectors observed in the middle to lower crusts of convergent zones have been identified as paired high and low velocity slabs which represent oceanic crust and mantle accreted via underplating to the continental margin 4 the crust mantle boundary may differ sufficiently when imaged with vertical incidence and wide angle data to justify the retention for the present of the concept of separate reflection and refraction mohos while there is good evidence that these features are coincident within measurement uncertainties in most regions recently recorded data from the basin and range admit the possibility for noncoincidence in that area 5 upper mantle reflections which cannot be migrated into the lower crust remain rare despite isolated unequivocal examples thus the upper mantle appears to be relatively homogeneous at seismic reflection wavelengths and to lack the laminations inferred for the lower crust the wide angle method will likely provide the most reliable information on the velocity structure and physical state of this portion of the lithosphere for some years to come 6 there appear to be clear and consistent basic differences between convergent and extensional terranes which have been identified from coincident experiments these differences may be sufficiently universal to infer the tectonic history of poorly exposed terranes 7 no truly three dimensional coincident experiment i e including three dimensional migration has been conducted but some three dimensional data have been collected using both methods measurements of attenuation poisson s ratio and anisotropy within the crust using coincident data sets remain frontiers

drainage evolution in the polish sudeten foreland in the context of european fluvial archives detailed study of subsurface deposits in the polish sudeten foreland particularly with reference to provenance data has revealed that an extensive preglacial drainage system developed there in the pliocene early pleistocene with both similarities and differences in comparison with the present day odra oder system this foreland is at the northern edge of an intensely deformed upland metamorphosed during the variscan orogeny with faulted horsts and grabens reactivated in the late cenozoic the main arm of preglacial drainage of this area at least until the early middle pleistocene was the palaeo nysa klodzka precursor of the odra left bank tributary of that name significant preglacial evolution of this drainage system can be demonstrated including incision into the landscape prior to its disruption by glaciation in the elsterian sanian and again in the early saalian odranian which resulted in burial of the preglacial fluvial archives by glacial and fluvioglacial deposits no later ice sheets reached the area in which the modern drainage pattern became established the rivers incising afresh into the landscape and forming post saalian terrace systems issues of compatibility of this record with the progressive uplift implicit in the formation of conventional terrace systems are examined with particular reference to crustal properties which are shown to have had an important influence on landscape and drainage evolution in the region

the western carpathians interaction of hercynian and alpine processes abstract the complicated structural and rheologic properties of western carpathian lithosphere reflect the complex geodynamic history of the carpathian orogen based on critical analysis of earlier models new interpolation of existing geophysical data and results of integrated modelling a new map of the lithosphere thickness for the carpathian pannonian region has been constructed the map allows for the distinction of a frontal orogen collision zone in the ne from increased lithosphere thickness as well as a zone of oblique collision with the bohemian massif in the west where lithosphere is not significantly thickened the moho discontinuity beneath the western carpathian hinterland danube and east slovak basins as defined by deep reflection seismic profiling is relatively shallow this probably reflects recent crustal extension related to oblique collision between the european plate and the alcapa block and an increase of the asthenospheric updoming from the middle miocene onward crustal thickness reflects the combined effects of deep seated orogenic processes and mantle thermal evolution beneath the pannonian basin system in this study we focus particularly the structures of 1 the late alpine collision and neogene back arc basin development including deep seated contacts between colliding plates a zone of slab detachment the compressional accretionary wedge of the outer western carpathian flysch belt and extensional structures produced by subduction rollback and asthenosphere upwelling 2 early alpine structures related to cretaceous thrust stacking including subhorizontal reflection packages interpreted as multi generational extensional structures the underplated intra penninic oravic continental ribbon and ophiolite traces of the meliatic oceanic suture and 3 north dipping reflectors interpreted as remnant hercynian lithotectonic fragments with opposed vergency to the subducted alpine units

a refined apparent polar wander curve for the transdanubian central mountains and its bearing on the mediterranean tectonic history abstract recently obtained palaeomagnetic data have given a fairly detailed apparent polar wander a p w curve for the mesozoic of the transdanubian central mountains which has been compared with other a p w curves from the mediterranean area the similarity of the a p w curves enabled a unified a p w curve to be constructed for the central mediterranean region it has been shown that the new mediterranean a p w curve is in full agreement even in details with the updated a p w curve for africa this confirms the existence during the entire mesozoic of a single central mediterranean megatectonic unit rigidly attached to africa its positions with respect to the pole can now be traced back in more detail than before

deep crustal structure beneath the central and inner west carpathians abstract the 150 km long deep seismic transect 2t crossing the central part of the slovakian west carpathians has revealed an important whole crustal seismic suture zone dipping to the south this zone is dominated by six large and several minor reflection events because of our good knowledge of the surface geology and a large number of comparative studies of the eastern alps it is clear that the upper reflections are due to overthrust sheets that originated during compression of the apulian passive margin tectonically deeper reflections are interpreted as being due to ligurian oceanic igneous and sedimentary rocks sheared in ductile domain during continental collision with the brianconnais passive margin and continental masses north of the central apulian west carpathians cwc behind a significant strike slip fault are the cenozoic structures of the pieniny klippen belt and the magura rhenodanubian flysch south of the cwc the inner tethyan west carpathians iwc are thrust over the cwc the iwc originated during the late jurassic early cretaceous closure of the tethyan ocean and the seismic image of the iwc is different from the highly reflective cwc suture these three pre neogene nappe systems amalgamated as one overthrust system during the neogene subduction of the moldavian sea as the moldavian accretionary wedge the vepor gemer block of the west carpathians where the cretaceous suture is observed has been untouched by any major cenozoic deformation and has remained relatively rigid this unique structure therefore enables us to observe seismically the cretaceous suture zone which elsewhere in the european alpine belt has been almost completely destroyed more general data about the beginning of subduction and subsequent collision processes are presented significant compression and partial subduction of the apulian upper plate passive margin lasted from the hauterivian to the beginning of the turonian for about 25 30 ma subduction of the ligurian ocean occurred from turonian to campanian times after the early campanian the collision of the apulian and brianconnais plates took place

new morphostructural subdivision of the western carpathians an approach integrating geodynamics into targeted morphometric analysis abstract a new quantitative method of morphostructure delimitation based on targeted morphometric analyses and multivariate statistical methods was applied to the western carpathians nine specific morphostructural regions and sixteen subregions were defined as an improvement on the preceding qualitative subdivision of the area the integration of geodynamics into the targeted morphometric analysis represents a prerequisite for better interpretability of the delimited regions the new subdivision of the western carpathians therefore reflects first of all the pliocene quaternary geodynamics that controls the development of the present day relief the results also help to understand the timing of the basic dome like morphostructural formation of the western carpathians which began 4 6 million years ago with the main stage continuing until the late pliocene and accelerated uplift taking place since the middle pleistocene as well as the mechanism of its formation the importance of the middle miocene extension for the development of the basin and mountain mosaic unique to the western carpathians is documented the projection of the older structural boundaries into the new morphostructural regions and the increasing prevalence of the young morpholineament systems n s and w e on the southern and northern periphery of the western carpathians could be an indication of the gradual spreading of the western carpathians into the surrounding lowlands during the last stage of the morphotectonic development

hydrography of the labrador sea during active convection the hydrographic structure of the labrador sea during wintertime convection is described the cruise part of the deep convection experiment took place in february march 1997 amidst an extended period of strong forcing in an otherwise moderate winter because the water column was preconditioned by previous strong winters the limited forcing was enough to cause convection to approximately 1500 m the change in heat storage along a transbasin section relative to an occupation done the previous october gives an average heat loss that is consistent with calibrated national centers for environmental prediction surface heat fluxes over that time period 200 wm 22 deep overturning was observed both seaward of the western continental slope which was expected as well as within the western boundary current itself something that had not been directly observed previously these two geographical regions separated by roughly the 3000 m isobath produce separate water mass products the offshore water mass is the familiar cold fresh dense classical labrador sea water lsw the boundary current water mass is a somewhat warmer saltier lighter vintage of classical lsw though in the far field it would be difficult to distinguish these products the offshore product was formed within the cyclonic recirculating gyre measured by lavender et al in a region that is limited to the north most likely by an eddy flux of buoyant water from the eastern boundary current the velocity measurements taken during the cruise provide a transport estimate of the boundary current throughput and offshore recirculation finally the overall trends in stratification of the observed mixed layers are described

moho reflectivity and seismic signal penetration abstract analysis of amplitude decay and frequency change is applied to determine limits of seismic signal penetration on deep seismic reflection data collected by lithoprobe and the consortium for continental reflection profiling cocorp changes in spectral frequency content are efficiently monitored with averaged instantaneous frequency and bandwidth results from montana show pronounced increases in average frequency and slight drops in amplitude associated with a die out of reflections at the moho results from quebec show amplitude and frequency change occurring through the moho on lines with and without moho reflections these contrasting observations confirm both adequate signal penetration and that the differences in moho reflectivity are representative of geologic differences

slab behaviour and its surface expression new insights from gravity modelling in the se carpathians abstract we use lithosphere scale gravity models to calculate gravity anomalies resulting from oceanic subduction continental collision slab steepening delamination and break off local isostasy was assumed for determining vertical movements caused by mass changes related to these tectonic processes our results show that subduction is accompanied by basin subsidence on the upper plate caused by the heavy lithospheric root of the subducting slab the basin evolution goes parallel with the slab evolution and shows considerable modifications when the processes at depth change slab steepening delamination break off characteristic gravity anomaly curves were acquired for the different tectonic scenarios these curves together with other data e g basin evolution on the upper and the lower plate were used for the reconstruction of the tectonic evolution of the se carpathians which includes tertiary subduction and collision followed by slab steepening and delamination

birps deep seismic reflection studies of the british caledonides the western isles north channel winch traverse fig 1 an extension of the successful moist profile1 was recorded in 1982 at sea along the west coast of britain for birps british institutions reflection profiling syndicate by the geophysical company of norway geco the purpose of the winch traverse was to study crustal structure of the caledonian foreland to cross the caledonian orogen and to establish the three dimensional geometry of mantle reflectors originally seen on moist we describe here the data first emphasizing british caledonian structures and then discussing features of the deep crust of wider significance the data are of very good quality and contain clear moho and upper mantle reflections the lower crust is surprisingly reflective deeply penetrative thrusts are observed and there is firm evidence that several of the mesozoic basins round the shores of the united kingdom were formed by reactivation of older features

observations of the labrador sea eddy field this paper is an observational study of small scale coherent eddies in the labrador sea a region of dense water formation thought to be of considerable importance to the north atlantic overturning circulation numerical studies of deep convection emphasize coherent eddies as a mechanism for the lateral transport of heat yet their small size has hindered observational progress a large part of this paper is therefore devoted to developing new methods for identifying and describing coherent eddies in two observational platforms current meter moorings and satellite altimetry details of the current and water mass structure of individual eddy events as they are swept past by an advecting flow can then be extracted from the mooring data a transition is seen during mid 1997 with long lived boundary current eddies dominating the central labrador sea year round after this time and convectively formed eddies similar to those seen in deep convection modeling studies apparent prior to this time the topex poseidon altimeter covers the labrador sea with a loose net of observations through which coherent eddies can seem to appear and disappear by concentrating on locating and describing anomalous events in individual altimeter tracks a portrait of the spatial and temporal variability of the underlying eddy field can be constructed the altimeter results reveal an annual pulsation of energy and of coherent eddies originating during the late fall at a particular location in the boundary current pinpointing the time and place of the boundary current type eddy formation the interannual variability seen at the mooring is reproduced but the mooring site is found to be within a localized region of greatly enhanced eddy activity notably lacking in both the annual cycle and interannual variability is a clear relationship between the eddies or eddy energy and the intensity of wintertime cooling these eddy observations as well as hydrographic evidence suggest an active role for boundary current dynamics in shaping the energetics and water mass properties of the interior region

the crustal and upper mantle geophysical signature of narrow continental rifts in the pannonian basin summary the pannonian basin provides a very good opportunity to study extensional tectonics the image of narrow continental rifts which represent one of the modes of continental extensional tectonics was studied in detail in the bekes basin in order to constrain the lithosphere structure beneath the narrow rifts in the pannonian basin density models and interpretation of magnetotelluric measurements along the pannonian geotraverse are presented the results obtained agree with the most recent deep seismic data most of the narrow rifts in the pannonian basin are characterized not only by thinner crust but also by thinner lithosphere a typical phenomenon of the gravity field over the central part of the narrow rifts in the pannonian basin is the existence of a relative local gravity high these gravity highs are probably due to intrusions of high density masses into the lower crust and lower part of the upper crust beneath the narrow rifts which are related to the extension of the basins subbasins

basalts water or shear zones in the lower continental crust abstract bright sub horizontal laterally extensive multi cyclic layered reflections have now been recorded in the lower continental crust from many areas in contrast this reflection signature is rare in the continental upper crystalline crust and upper mantle and in the oceanic lithosphere with the present state of knowledge it is sensible to seek a single quantitative explanation for all such layering qualitative explanations for lower crustal layering abound and include igneous metamorphic structural and fluid related models measurements of reflection coefficients from the lower crust place strong quantitative constraints on possible models structurally induced anisotropy metamorphic layering or free fluids cannot realistically produce sufficiently bright reflections igneous layering or the juxtaposition of pre existing heterogeneities by shear zones can produce strong reflections results from crustal xenoliths helium isotope ratios palaeo geothermal gradients and chemistry of flood basalts together with numerical modelling of lithospheric extension and asthenospheric melting suggest that underplating and intrusion of the lower crust with mantle derived mafic igneous rocks is common the apparent spatial relationship between lower crustal layering and continental extension and the strength and continuity of the reflections suggest that underplating related to extension and or elevated mantle temperatures is a good explanation for lower crustal layering

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

gravity constraints on the crustal structure and slab evolution along a transcarpathian transect abstract a new unified bouguer anomaly map of the carpathian arc and the pannonian basin has been compiled from previously prepared and recently published gravity maps in order to constrain the crustal structure and the tectonic evolution of the area a two dimensional gravity model is presented along a western carpathians pannonian basin southern carpathians transect the model is based on deep seismic lines where available and on detailed geological sections the results confirm that the extensional crustal structure of the pannonian basin revealed by deep seismic surveys agrees with the gravity data furthermore they suggest that the western and southern carpathians area at different stages of their evolution the subducted oceanic slab under the western carpathians has already been assimilated to the asthenosphere while a crustal slab is still present under the southern carpathians these findings are compatible with the observation that the last major phase of crustal shortening terminated at the early middle miocene in the western carpathians but continued throughout the pliocene in the southern carpathians

rheology predictions across the western carpathians bohemian massif and the pannonian basin implications for tectonic scenarios on the basis of extrapolation of failure criteria lithology and temperature models we predict the rheology of the lithosphere for several sections through the carpathians and surrounding regions our models show significant lateral variations in rheology for the different tectonic units with important implications for the tectonic evolution the theologically strong lithosphere of the polish platform area contrasts with the weak lithosphere of the pannonian basin indicating that the arcuate shape of the carpathian orogen is primarily caused by an inherited curvature of an ancient embayment in the foreland with the pannonian units passively filling the space the polish platform and the moesian platform exhibit a similar rheological anisotropy caused by nw se trending weakness zones paralleling the tornquist teisseyre zone this anisotropy was the main controlling factor on the behavior of the lithosphere in this area since cadomian times as documented by the geological evolution of the sudety mountains and the mesozoic polish trough including the late cretaceous alpine inversion and the neogene development of the carpathian foreland this rheological anisotropy appears to have a major controlling impact on the development of at least the eastern part of the european lithosphere rheology predictions for the bohemian massif support the idea that the rigid lithosphere of the bohemian massif governed the bending of the alpine carpathian transition zone expressed in the large scale wrench movements opening the vienna basin in the foreland area detachment levels are predicted for upper and lower crustal levels leading to a decoupling of crustal and subcrustal flexure in most areas comparison with basin formation models indicates that our predictions for effective elastic thickness eet are similar to those derived from flexural models for the foreland area also eet predictions from extensional basin models in the pannonian region yield values close to our findings

tectonic rotations south of the bohemian massif from palaeomagnetic directions of permian red beds in hungary abstract palaeomagnetic studies were carried out in permian red beds of the balaton highlands the mecsek mountains and the bukk mountains of hungary statistically well defined directions were obtained from six localities in the balaton highlands and two localities in the mecsek mountains no meaningful results were obtained from the bukk mountains three magnetic components were identified from red beds of the balaton highlands 1 in haematite with a very high unblocking temperature 700 c interpreted as a permian magnetization d c 79 i c 11 k 24 95 13 6 in six samples from three beds in a single locality 2 a secondary but ancient component residing mainly inmaghemite d 314 i 49 k 48 95 10 0 in 84 samples from six localities with a within locality scatter increasing on unfolding and 3 a direction parallel to the present field d 7 i 62 k 46 95 7 7 in nine samples from a single locality for the balaton highlands the component 1 direction agrees with directions obtained from permian red beds and volcanics in the eastern part of the southern and eastern alps and the inner west carpathians all show large apparent rotations relative to stable europe since the permian component 2 is of post folding post aptian age its direction agrees with known late cretaceous directions from the transdanubian central mountains which also show significant counterclockwise rotation relative to stable europe the characteristic magnetization for the mecsek mountains resides in haematite and may be primary the directions indicate only a slight net counterclockwise rotation of the mecsek mountains with respect to stable europe since the permian

death valley bright spot a midcrustal magma body in the southern great basin california a previously unrecognized midcrustal magma body may have been detected by cocorp deep seismic reflection profiles in the death valley region of the southern great basin high amplitude relatively broad band reflections at 6 s 15 km are attributed to partially molten material within a subhorizontal intrusion this bright spot extends laterally at least 15 km beneath central death valley a moderately dipping normal fault can be traced from the inferred magma chamber upward to a 690 000 yr old basaltic cinder cone the fault zone is inferred to have been a magma conduit during the formation of the cinder cone vertical variations in crustal reflection character suggest that the death valley magma body may have been emplaced along a zone of decoupling that separates a faulted brittle upper crust from a more ductile and or intruded lower crust the death valley bright spot is similar to reflections recorded by cocorp in 1977 in the rio grande rift where both geophysical and geodetic evidence support the inference of a tabular magma chamber at 20 km depth

observations of seismic reflectors in the lower lithosphere beneath the skagerrak the lithosphere the rigid outer shell of the earth includes both the crust and the upper mantle in the past decade the complex continental crust and underlying shallower mantle lithosphere have been extensively studied using reflection seismology but the lower lithosphere has not been successfully imaged here we report the observation of continuous and virtually horizontal reflectors in the lower continental lithosphere down to depths of 100 110 km below the skagerrak scandinavia these are apparently not structurally associated with the crust whereas previously reported mantle reflectors such as those observed by the birps group around the british isles1 2 are often located near large faults in the overlying crust like the crust the mantle lithosphere shows a seismically transparent upper and a reflective lower part thus the processes that form seismic reflectors seem to have an affinity for ductile rheological environments in the mantle as well as in the crust our observations are consistent with a model consisting of a mechanically strong upper lithosphere underlain by a thermal boundary layer which separates it from the convecting asthenosphere

localised continental shelf waves geometric effects and resonant forcing alongshore variations in coastline curvature or offshore depth profile can create localised regions of shelf wave propagation with modes decaying outside these regions these modes termed localised continental shelf waves csws here exist only at certain discrete frequencies lying below the local maximum frequency and above the far field maximum frequency for propagating shelf waves the purpose of this paper is to obtain these frequencies and construct both analytically and numerically and discuss csws for shelves with arbitrary alongshore variations in offshore depth profile and coastline curvature if the shelf curvature changes by a small fraction of its value over the shelf section of interest or an alongshore perturbation in offshore depth profile varies slowly over the same length scale then csws can be constructed using wkbj theory two subcases are described i if the propagating region is sufficiently long that the offshore structure of the csw varies appreciably alongshore then the frequency and alongshore structure are found from a sequence of local problems ii if the propagating region is sufficiently short that the alongshore change in offshore structure of the csw is small then the alongshore modal structure is given in an explicit uniformly valid form a separate asymptotic theory is required for curvature perturbations to shelves that are otherwise straight rather than curved comparison with highly accurately numerically determined csws shows that both theories are extremely accurate with the wkbj theory having a significantly wider range of applicability an idealised model for the generation of csws is also suggested a localised time periodic wind stress generates an evanescent continental shelf wave in the far field of a localised mode where the coast is almost straight and the response on the shelf is obtained numerically if the forcing frequency is close to that of an csw then the wind stress excites energetic motions in the region of maximum curvature creating a significant localised response possibly far from the forcing region

topographic waves and the evolution of coastal currents an initial value problem is considered for the oceanographically relevant case of slow flow over obstacles of small height and horizontal scale of order the fluid depth or larger previous work on starting flow over obstacles whose contours are closed johnson 1984 is extended to flow forced by a source sink pair to cross a step change in depth bounded by a vertical sidewall bottom contours thus end abruptly and the near periodic solutions of the earlier work are no longer possible the relevant timescale for the motion is again the topographic vortex stretching time h 2 h0 where h is the fluid depth the background rotation rate and h0 the step height this time is taken to be long compared with the inertial period but short compared with the advection time it is shown that if shallow water lies to the right looking away from the wall a wavefront moves outwards exponentially fast leaving behind a flow equivalent to that obtained by replacing the step by a rigid wall if shallow water lies to the left the wavefront approaches the wall forming at the wall step junction an unsteady exponentially thinning singular region that transports the whole flux the relevance of these solutions to experiments and steady solutions for free surface and two layer flows in davey gill johnson linden 1984 1985 is discussed

evolution of the stress fields in the carpatho pannonian area during the neogene abstract observations of microtectonic faults in and around the pannonian basin suggest that the tertiary evolution of the area was controlled by large scale strike slip fault activity statistical analysis of the fault pattern for different localities makes it possible to separate several conjugate sets of strike slip faults and related dilatational and compressive structures these stress fields have a distinct rotation pattern with time inversion of fault data suggests a characteristic rotation of the principal stress axes with time some rigid body rotations are indicated by paleomagnetic data there are basically three contrasting mechanisms to explain this observation 1 1 appropriate rotation of the regional e g european stress field 2 2 rotation of larger tectonic units e g microcontinents under a stable regional stress field and 3 3 coherent rotation of smaller detached continental blocks under a stable regional stress field our model for the neogene tectonic evolution of the pannonian area combines these mechanisms moderate microcontinent rotation may have occurred during the paleogene early miocene in the early middle miocene the microcontinents were dissected by a system of strike slip and normal faults created by a n s compressive e w extensive stress field gravity spreading of the pannonian units and block rotation within bounding strike slip faults are suggested to explain rotated magnetic directions and fault patterns in the late neogene clockwise rotation of the general stress field by at least 40 is thought to be responsible for the reactivations of older strike slip faults and for the creation of new sets this change in the orientation of the stress field is related to the eastward and then southward shift of the carpathian subduction activity

a preliminary stripped gravity map of the pannonian basin abstract by removing the gravity effects of the known near surface sources from the gravity map we obtain a stripped gravity map that enables a better interpretation of the deep seated geological structures of the earth s crust the total gravity effect of anomalous bodies is acquired by summation of the gravity effects of n sided vertical prisms with horizontal bases the stripping procedure has a more accurate physical foundation than any other mathematical method of gravity field analysis provided that the geometry and density of the disturbing bodies are known with sufficient accuracy this method was applied to the pannonian basin

tomographic images of the upper mantle below central europe and the mediterranean results from delay time tomography of the european mediterranean upper mantle are discussed and where possible interpreted in terms of geodynamic processes slab like positive velocity anomalies of which the locations correlate well with deeper seismicity are found beneath spain the tyrrhenian basin and the aegean these structures are interpreted as images of subducted slabs large aseismic regions with positive velocity anomalies are found beneath the western mediterranean italy the alps dinarides the pannonian basin northern greece and the aegean these anomalies can also be linked to subducted lithosphere from the anomaly patterns it is deduced that subduction occurred below the western mediterranean and along both sides of the adriatic micro plate beneath the dinarides and northern greece the velocity structures suggest detachment of the slab from the surface

styles of extension in the pannonian basin abstract structural interpretation of reflection seismic profiles reveals distinct modes of upper crustal extension in the pannonian basin while some subbasins in the pannonian basin complex show little extension planar rotational normal faults others are characterized by large magnitude of extension detachment faults metamorphic core complexes gravitational collapse of the intra carpathian domain combined with subduction zone roll back is thought to be the driving mechanism of the neogene back arc extension the very heterogeneously distributed extension is accommodated by transfer faults which bound regions characterized by different polarity direction or amount of extension in cross section these transfer faults are characterized by flower structures typical for strike slip faults seismic stratigraphic interpretations indicate that the non marine post rift sedimentary fill of the pannonian basin can be described in terms of sequence stratigraphy the exceptionally good seismic sequence resolution allows recognition of third order and also fourth order depositional sequences which may reflect the interplay of tectonics and eustasy and milankovitch scale climatic variations respectively

interplay of tectonics and neogene post collisional magmatism in the intracarpathian region abstract distribution of the neogene calc alkaline magmatism of the carpathian arc is directly related in space and time to the kinematics of the two major terranes of the intracarpathian area alcapa tisia getia along the south eastern border of the european plate in the west carpathians and adjacent areas the volcanic activity occurred between 20 11 ma with large volumes of both acidic and intermediate rocks generally distributed randomly sometimes transversally to the orogenic belt and as rare small occurrences along the flysch belt in the east carpathians the volcanic rocks are distributed along the northern margin of the zemplin block the north easternmost part of the alcapa and eastward along the front of the getic block at the contact with european plate between tokaj slanske vihorlat up to northern calimani mountains the magmatism occurred between 14 9 ma and along the calimani harghita chain between 9 0 2 ma the calc alkaline magmatic rocks of the apuseni mountains are located in the interior of the tisia block and occurred between 14 9 ma the generation of the calc alkaline magmatism is considered here as the result of complex interplay between plate roll back and lithospheric detachment tectonic processes and the break off of the subducted plate mostly in a post collisional setting 1 the magmatites of the western carpathians and the pannonian basin were generated in direct relation to subduction roll back processes over the downgoing slab during the period of lateral extrusion and back arc extension in this area characterized by maximum crustal shortening we can infer further delamination processes to explain the generation of magmas 2 the magmatic rocks from the northern sector of the east carpathians tokaj slanske vihorlat up to the northern calimani mountains resulted after subduction roll back processes and an almost simultaneous break off of the descending plate all along the arc segment during main clockwise rotation of the intracarpathian terranes 3 in the eastern sector of the east carpathians calimani up to harghita mountains the magmatic rocks were generated through partial melting of the subducted slab followed by gradual break off of the subducted plate along strike north to south 4 the apuseni mts magmatic activity resulted in transtensional tectonic regime by decompressional melting of lithospheric mantle during the translation and rotation of tisia getia block

meanders and eddies from topographic transformation of coastal trapped waves abstractthis paper describes how topographic variations can transform a small amplitude linear coastal trapped wave ctw into a nonlinear wave or an eddy train the dispersion relation for ctws depends on the slope of the shelf provided the cross shelf slope varies sufficiently slowly along the shelf the local structure of the ctw adapts to the local geometry and the wave transformation can be analyzed by the wentzel kramers brillouin jeffreys wkbj method two regions of parameter space are straightforward adiabatic transmission where at the incident wave frequency a long wave exists everywhere along the shelf and short wave reflection where somewhere on the shelf no long wave exists at the incident frequency but the stratification is sufficiently weak that a short reflected wave can coexist with the incident wave this paper gives the solutions for these two cases but concentrates on a third parameter regime which includes all sufficiently strongly stratified flows where neither of these

crustal and upper mantle structure of the western carpathians from celebration 2000 profiles cel01 and cel04 seismic models and geological implications summary celebration 2000 was a large international experiment that focused on the lithospheric structure in central europe it consisted of several wide angle reflection and refraction seismic profiles profiles cel01 and cel04 are located in the transition from the precambrian and palaeozoic platforms to the carpathian orogen the data were modelled using 2 d tomographic and forward modelling techniques the profile cel01 about 900 km long extends from the southwestern margin of the east european craton to the pannonian basin system the depth of moho boundary varies along the profile from 27 33 km under the pannonian basin system area 30 39 under the carpathians and within the tesz to 40 45 km under the east european craton the cel04 profile 630 km long starts in the polish trough pt and reaches the pannonian basin system along the cel04 profile the moho interface shallows from 40 km beneath the pt to about 35 km in the maopolska unit the crustal thickness is 43 km beneath the carpathians and 25 km beneath the pannonian basin system the results obtained are consistent with a commonly accepted view of the carpathians thought to be formed largely due to the interplay between palaeogene to middle miocene subduction of oceanic or suboceanic crust and subsequent collision a feature that we interpret as the subduction related orogenic root is at least partially preserved in both profiles and is manifested by a crustal thicknesses of 39

entrainment of shelf water by a bifurcating continental boundary current abstract at the northeast corner of taiwan the direction of the continental slope isobaths changes rapidly relative to the oncoming kuroshio so that the inertia of a small inshore fraction of this current causes it to cross the slope while the main branch follows the isobaths it is suggested that the portion of the bifurcated current entering the shelf displaces ambient water of relatively high potential vorticity as a countercurrent which flows across the slope the vortex stretching and subsequent entrainment of this water into the main branch of the kuroshio increases its maximum cyclonic vorticity and helps to maintain the inshore shear of the western boundary current this idea is supported by simple initial value and steady state models and also by dye observations of the flow from a source on the wall of a rotating tank

observations of open ocean deep convection in the labrador sea from subsurface floats abstract the occurrence and extent of deep convection in the labrador sea in winters 1996 97 and 1997 98 is investigated from measurements of over 200 neutrally buoyant subsurface profiling autonomous lagrangian circulation explorer palace and sounding oceanographic lagrangian observer solo floats in addition to providing drift velocity data and vertical profiles of temperature and salinity 55 floats are equipped with vertical current meters vcms time series of vertical velocity derived from measured pressure and vertical flow past the float and temperature are obtained from the vcm floats mixed layer depths estimated from profile measurements indicate that convection reached depths greater than 1300 m in 1997 but no deeper than 1000 m in 1998 deep mixed layers were concentrated in the western basin although a number of deep mixed layers were observed southwest of cape farewell and also north of 60 n the highest variance in vertical velocity and the lowest mean temperatures were found in t

gamma ray spectrometry in the field radioactive heat production in the central slovakian volcanic zone we report 62 sets of measurements from central southern slovakia obtained using a modern portable gamma ray spectrometer which reveal the radioactive heat production in intrusive and extrusive igneous rocks of the late cenozoic central slovakian volcanic zone sites in granodiorite of the stiavnica pluton are thus shown to have heat production in the range 2 2 4 9 w m 3 this variability being primarily a reflection of variations in content of the trace element uranium sites in dioritic parts of this pluton have a lower but overlapping range of values 2 1 4 4 w m 3 sites that have been interpreted in adjoining minor dioritic intrusions of similar age have heat production in the range 1 4 3 3 w m 3 the main stiavnica pluton has zoned composition with potassium and uranium content and radioactive heat production typically increasing inward from its margins reflecting variations observed in other granodioritic plutons elsewhere it is indeed possible that the adjoining dioritic rocks hitherto assigned to other minor intrusions of similar age located around the periphery of the stiavnica pluton in reality provide further evidence for zonation of the same pluton the vicinity of this pluton is associated with surface heat flow 40 mw m 2 above the regional background on the basis of our heat production measurements we thus infer that the pluton has a substantial vertical extent our preferred estimate for the scale depth for its downward decrease in radioactive heat production being 8 km nonetheless this pluton lacks any significant negative bouguer gravity anomaly we attribute this to the effect of the surrounding volcanic caldera filled with relatively low density lavas masking the pluton s own gravity anomaly we envisage that emplacement occurred when the pluton was much hotter and thus of lower density than at present its continued uplift evident from the local geomorphology being the isostatic consequence of localized erosion the heat production in this intrusion evidently plays a significant role hitherto unrecognized in the regional geothermics

the ecors deep reflection seismic survey across the pyrenees the pyrenees are an alpine age mountain belt located on the boundary between the iberian and european plates using the same geological and geophysical data earth scientists studying the structure of the pyrenees during the past ten years have not reached a consensus here we report the first results from a nearly continuous 255 km long reflection seismic survey across the pyrenean chain this first deep reflection profile of an entire erogenic belt will help to constrain possible models for the structure and formation of the pyrenean chain

travel time tomography of the european mediterranean mantle down to 1400 km abstract the 3 d p wave velocity structure of the mantle below europe the mediterranean region and a part of asia minor is investigated this study is a considerable extension of an earlier tomographic experiment that was limited to imaging upper mantle structure only here the earth s volume under study encompasses the mantle to a depth of 1400 km and we increase the number of international seismological centre isc data for inversion by a factor of four by taking more years of observation and by including data from teleseismic events the most important departure from the earlier study is that we do not use the jeffreys bullen model as a reference model but an improved radially symmetric velocity model the pm2 model which is appropriate for the european mediterranean mantle our inversion procedure consists of two steps first the radial model pm2 is determined from the isc delay times by a nonlinear trial and error inversion of the data as opposed to the jeffreys bullen model the new reference model has a high velocity lithosphere a low velocity zone and seismic discontinuities at depths of 400 and 670 km next the isc data are corrected for effects related to the change in reference model and inverted for 3 d heterogeneity relative to the pm2 model we follow this two step approach to attain a better linearizable tomographic problem in which ray paths computed in the pm2 model provide a better approximation of the actual ray paths than those computed from the jeffreys bullen model hence the two step scheme leads to a more credible application of fermat s principle in linearizing the tomographic equations inversion results for the 3 d heterogeneity are computed for both the uncorrected isc data and for the pm2 data the data fit obtained in the two step approach is slightly better than in the inversion of isc data using the jeffreys bullen reference model a comparison of the tomographic results demonstrates that the pm2 data inversion is to be preferred to assess the spatial resolution an analysis is given of hit count patterns sampling of the mantle by ray paths and results of sensitivity tests with 3 d synthetic velocity models the spatial resolution obtained varies with position in the mantle and is studied both in map view and in cross section in the well sampled regions of the mantle the spatial resolution for larger scale structure can qualitatively be denoted as reasonable to good and at least sufficient to allow interpretation of larger scale anomalies a comparison is made of the results of this study with independent models of s velocity heterogeneity obtained in a number of investigations and with a prediction of the seismic velocity structure of the mantle computed from tectonic reconstructions of the mediterranean region in the context of this comparison interpretations of large scale positive anomalies found in the mediterranean upper mantle in terms of subducted lithosphere are given specifically addressed are subduction below southern spain below the western mediterranean and italy and below the aegean in the last region a slab anomaly is mapped down to depths of 800 km

on the geothermal regime of the moesian platform and getic depression abstract a total of 48 geothermal gradient measurements in thermally stabilized boreholes fairly uniformly distributed over the study area enabled a heat flow map to be produced and the relationship between tectonics and heat flow to be discussed simple conductive models were constructed for two profiles revealing interesting features of the deep thermal structure the thermal regime of the study area is related to major tectonic features such as crustal faults thrusting and large scale intrusive bodies

a new model for the acquisition of thermoremanence by multidomain magnetite isothermal remanence irm induced in multidomain grains at a high temperature t decreases on cooling in zero field the intensity and stability against temperature change of the irm depend on whether the temperature t was reached from a higher temperature or from a lower temperature these results cannot be explained by the existing multidomain theories a new model of trm thermoremanence acquisition mechanism in which domain wall interactions play the major role is proposed this model explains the main features of the experimental results very well and predicts an almost linear relationship between trm and the inducing field up to relatively high fields