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

interplay between subduction retreat and lateral extrusion tectonics of the western carpathians 1 analysis of brittle microstructures reveals three tertiary deformation events in the western carpathians 1 late paleogene bedding parallel extension 2 oligocene to middle miocene nne ssw compression and ese wnw extension 3 post mid miocene nw se extension these regional deformations applied to crustal blocks in the intra carpathian region resulted from forces which were induced by the coupled plate tectonic processes of subduction retreat beneath the carpathian arc and lateral extrusion from the eastern alps toward the carpathian region material flow from the alps spread toward east and ne guided by sinistral strike slip zones along the ne trending continental margin subduction retreat was terminated by mid miocene soft collision of the inner western carpathians with the european foreland ongoing subduction retreat beneath the eastern carpathians caused post mid miocene back arc extension forming the pannonian basin extension spread into the western carpathians by reactivating the extrusion related strike slip faults as normal faults

the exeter group south devon england a contribution to the early post variscan stratigraphy of northwest europe the lower part of the post variscan succession around exeter south devon england comprises some 800 m of breccias with subordinate sandstones and mudstones which rest upon devonian and carboniferous rocks folded during the variscan orogeny and are overlain disconformably by the aylesbeare mudstone group early triassic these deposits comprise the most westerly of the early post variscan successions preserved onshore in northwest europe and lie to the south of the variscan deformation front they are assigned to the exeter group new term geochronological and palaeontological studies in conjunction with detailed geological mapping show that the constituent formations comprise a lower late carboniferous early permian sequence separated from an upper late permian sequence by an unconformity which represents an hiatus with a duration of at least 20 m y the lower sequence contains volcanic rocks dated at between 291 and 282 ma early permian and pre dates intrusion of the nearby dartmoor granite 280 ma in the overlying palynologically dated late permian sequence older breccias contain clasts of the dartmoor granite aureole rocks and younger ones contain clasts of that granite the lower sequence occurs mainly within the crediton trough an east west trending partly fault bounded sedimentary basin that probably formed by extensional reactivation of a variscan thrust breccias in this sequence formed largely on alluvial fans the common occurrence of debris flows and a down fan passage from gravity flows into fluvially deposited sediments is typical of deposition on semi arid fans the upper late permian sequence is more widespread but includes similar deposits overlain at the top of the exeter group by aeolian dune and interdune deposits correlation within the laterally variable facies associations which comprise these sequences has been achieved using a combination of sedimentary facies analysis sedimentary geochemistry and petrographical and geochemical clast typing the stratigraphy revealed within the exeter group is broadly comparable with that recognized in the early post variscan rotliegend successions elsewhere in europe this similarity may however be deceptive the upper part of the exeter group may be coeval with the zechstein and apparently correlatable major unconformities in the group and the rotliegend may reflect different events in the variscan fold belt and variscan foreland areas respectively

subsidence analysis and quantitative basin modelling in the styrian basin pannonian basin system austria abstract we present the results of subsidence analysis and of quantitative basin modelling using isostatical and flexural models for basin evolution along four cross sections in the styrian basin the westernmost subbasin of the pannonian basin system subsidence analysis reveals a first ottnangian karpatian synrift phase our local isostatic models predict crustal stretching values up to 1 3 and subcrustal stretching values of 1 6 for this event stretching factors of a minor sarmatian extension phase are below 1 04 the termination of subsidence during the pannonian and a rapid quaternary uplift phase can be explained by major changes in the regional stress field a w e cross section through the northern furstenfeld subbasin provides a key for the understanding of the dynamics of basin formation it crosses a narrow karpatian rift basin the metamorphic core complex of the penninic eisenberg window and shows an eastward tilting of the easternmost part of the basin during pannonian times uplift of the penninic window can only be modelled with an extremely weak lithosphere equivalent elastic thickness eet 2 km whereas a best fit between observed and modelled tilting is obtained with an eet value of 5 km these results suggest that the lithosphere was extremely weak during the onset of basin evolution in ottnangian karpatian times probably caused by high extension rates and high heat flows associated with karpatian to early badenian magmatic activity subsequent cooling led to a pronounced increase in flexural rigidity an eet of 5 km fits well with estimations in other parts of the pannonian realm depth dependent rheology models based on palaeo heat flow estimates indicate a similar increase in lithospheric strength with time the impact of plio pleistocene volcanism on rheology appears to be relatively modest which can be explained by a deep position of the magma chamber for this event

sequential architecture and cyclicity in permian desert deposits brodick beds arran scotland this study of ancient desert deposits permian brodick beds tests the possibility that cyclicityin these interbedded aeolian fluvial and lacustrine deposits was orbitally controlled the 740 m thicksuccession of desert deposits forms one sequence which can be divided into three genetic units a majordeflation surface forms the basal sequence boundary and represents a drop in base level groundwatertable on top of the sequence boundary are rather uniform aeolian dune and sand sheet sediments unit1 formed in an erg during low base level with increasing rates of base level rise they are followed byinterbedded aeolian dune aeolian sand sheet and flood reworked aeolian sediments unit 2 representingerg margin deposits formed during increasing rates of base level rise the uppermost part of the sequenceis composed of gravel sheets unit 3 representing alluvial fan deposition during a high base level withdecreasing rates of base level rise the succession is cyclic and spectral analysis of sedimentary andgeochemical parameters reveal cycles with a thickness of 25 7 29 3 m 34 5 m and 64 5 m and fieldworkreveals cycles of 155 m and 675 m these sedimentary cycles are thought to reflect climatic oscillations the lack of detailed time control makes it diffcult to link these climatic fluctuations to orbital cycles although the detected cyclicity matches well with milankovitch theory

new evidence for block and thrust sheet rotations in the central northern calcareous alps deduced from two pervasive remagnetization events 1 we present 81 paleomagnetic sites early triassic to early cretaceous from the central sector of the northern calcareous alps nca eastern alps austria and germany stepwise thermal demagnetization defines three magnetic directions mostly carried by low unblocking temperature and low coercivity minerals j3 350 j2 500 j1 575 and 680 j3 and j2 show positive inclinations whereas j1 very seldom is of dual polarity the fold tests show that a j3 can be interpreted as a postfolding and posttilting remagnetization and j2 as a postfolding and pre syn tilting j1 can be considered as primary because of the occurrence of two polarities and evidence presented by other authors in the area all three components show a systematic and significant clockwise rotation after comparing with the expected european references j2 or j1 are marked by higher rotation values than j3 j2 shows different inclinations depending on the structural position north or southward dips considering the structural evolution and the observed inclinations the first postfolding and pretilting remagnetization event j2 could have taken place between late cretaceous and eocene times but certainly before the thrusting of the nca over the rhenodanubian flysch and northward tilting caused by the stacking of the lower austroalpine nappes the second postfolding and posttilting remagnetization j3 would have been acquired after the final thrusting of the nca over penninic units from then the nca behaved as a set of rigid blocks recording the main stage of vertical axis clockwise rotation 65 in average associated with the continental collision the variable degree of rotation in the different positions from 40 to 134 can be explained by individual vertical axis rotation in a block system trying to adjust to space problems the constant declination differences between j2 and j3 25 in average would reflect the rotation related with the lateral differences of shortening during the oblique thrust of the austroalpine units over the penninic units

erg margin deposits in the lower jurassic moenave formation and wingate sandstone southern utah the moenave formation dinosaur canyon member and the closely associated wingate sandstone in southern utah represent the southwestern erg margin of the lower jurassic wingate erg the erg margin deposits which extend across a 50 to 100 km wide region are composed of dune eolian sand sheet mud flanked eolian sabkha ephemeral stream and lacustrine facies the succession is divided into a basal erg margin association 8 27 m dominated by eolian facies and an overlying erg margin association as much as 90 m thick composed mainly of fluvial and lacustrine facies the sediments of the basal association are composed of three drying upward or locally drying wetting upward sequences that can be traced from the erg margin 100 km slightly upwind that is toward the west northwest into the outer erg margin zone sequences of the inner erg margin zone contain dune facies in their upper parts sequences in the intermediate erg margin zone contain sand sheet facies and those in the outer erg margin zone contain sabkha facies the basal association thins markedly toward the west northwest sediments of the overlying association contain up to six drying upward or drying wetting upward sequences but are apparently only fully preserved in the outer erg margin zone individual sequences show much lateral variation but characteristically contain lower muddy ephemeral stream deposits and upper sandy ephemeral stream deposits sand sheet deposits or incipientdune deposits the general time trend is interpreted as a gradual change toward a more humid climate the stacked drying upward or drying wetting upward sequences suggest that this long term climatic change was characterized by a number of fluctuations between relatively arid and humid conditions these climatic fluctuations apparently controlled both sediment yield to the basin and the depositional conditions in the erg margin region during arid intervals ephemeral braided streams transported sandy bed load into the erg margin area where eolian reworking took place during humid intervals sheet floods and high sinuosity rivers transported a more mud rich sediment load into the basin where eolian activity was minimal

clockwise paleomagnetic rotations in the alps in the light of the structural pattern of the transdanubian range hungary abstract in the northeastern transdanubian range the sw ne trending structures bend towards the southeast resulting in a clockwise rotation clockwise rotation of paleomagnetic directions is known in the middle part of the northern calcareous alps and is presumed in the carnic alps areas further west are characterized by a uniform anticlockwise paleomagnetic rotation based on the norian facies pattern the intra alpine position of the transdanubian range can be restored in its restored form the arched section of the range lies between the alpine areas with clockwise paleomagnetic rotations it is suggested that initial structural bends existed in both the upper austro alpine and the south alpine domains which have subsequently been masked by new tertiary structures the bend in the transdanubian range has been preserved since this domain had been removed from the alpine realm before the tertiary orogeny this alpine pannonian structural bend formed in the middle cretaceous the recognition of this bending is recent and it influences the reconstruction of the central mediterranean

high resolution stratigraphy and depositional model of wind and water laid deposits in the ordovician guaritas rift southernmost brazil abstract the upper portion of the pedra pintada alloformation includes about 100 m of mostly eolian deposits this paper emphasizes the vertical succession and lateral association of sedimentary facies based on analysis of outcrop data and aerial photographs as well as the hierarchy and origin of bounding surfaces it aims to propose a high resolution stratigraphic and depositional model that may be useful to exploitation of eolian reservoirs the succession has been preserved due to basin subsidence and is described in terms of four facies associations that constitute three dominantly eolian units these units are sharply bounded by major flooding surfaces super surfaces that in turn are overlain by 1 to 2 m thick dominantly water laid facies lacustrine fluvial deltaic and eolian both their internal organization and boundaries were controlled by changes in the base level rise rate the basal eolian unit is composed of crescentic eolian dunes and damp interdune deposits ascribed to a wet eolian system on the other hand eolian units ii and iii also characterized by crescentic eolian dunes simple and compound deposits were related to dry eolian systems since they comprise dry eventually wet interdune facies eolian unit iii is truncated by basinwide unconformity which is then overlain by the ephemeral fluvial deposits varzinha alloformation this second type of super surface is related to climate induced wind erosion deflation down to the water table level regional stokes surface followed by fluvial incision linked to tectonic activity

astronomical frequencies for pre quaternary palaeoclimate studies the sensitivity of the earth s orbital frequencies involved in the astronomical theory of palaeoclimates to the earth moon distance and consequently to the length of the day and to the dynamical ellipticity of the earth has been investigated for the last billion years the shortening of the earth moon distance and of the length of the day back in time induces a shortening of the fundamental astronomical periods for the obliquity and the precession a shortening which is larger for the longer periods these periods of precession and obliquity influenced by the changing earth moon distance length of the day and dynamical ellipticity of the earth have been recomputed for the last 440 million years

skilful predictions of the winter north atlantic oscillation one year ahead the north atlantic oscillation profoundly influences european and north american winter weather dynamical model predictions now exhibit skill in prediction of the winter north atlantic oscillation more than one year in advance

development of pull apart basins a comparative study of well mapped active and ancient pull apart basins suggests a qualitative model for their continuous development pull aparts evolve from incipient to extremely developed basins through a sequence of closely related states new and compiled map data from several areas including the northern caribbean and turkey suggests the following stages in pull apart development 1 in rigid intracontinental strike slip plate boundary zones larger pull aparts nucleate at releasing fault bends along segments of the principal displacement strike slip fault zone which are oblique to the theoretical interplate slip lines 2 initial opening across releasing fault bends produces spindle shaped basins defined and often bisected by oblique slip faults connecting the discontinuous ends of the strike slip faults 3 increased strike slip offset produces basin shapes which we colloquially call lazy s shape for basins between sinistral faults and lazy z shape for basins between dextral faults 4

the effects of fluctuating base level on the structure of alluvial fan and associated fan delta deposits an example from the tertiary of the betic cordillera spain the villanueva complex is a lacustrine alluvial fan fan delta system which accumulated on the northern margin of the guadix basin during the pliocene five transitional zones can be distinguished from proximal to distal areas proximal alluvial fan mid fan fan fringe transition zone proximal fan delta and distal fan delta lacustrine this paper focuses on sedimentation in the fan fringe and the proximal fan delta areas where the effects of fluctuations in the base level lacustrine level are more easily observed the stratigraphical succession is here characterized by an alternation of fine lacustrine sediments mudstones and siltstones and gravels the gravels appear as isolated channels stacked channels lenses and sheets the isolated channels which have a v shaped profile and better developed wings towards the top appear in the fan fringe zone and in the fan delta the stacked channels originate in the fan fringe zone and evolve laterally and distally to isolated channels the lenticular gravel bodies lenses are well represented throughout the fan delta and present small channels at the base indicating a radial flow pattern finally the sheets are characteristic of the fan fringe zone the first episodes of channel incision occurred at lowstand lake level the channels and lenses developed in rising lake level conditions and sheet deposit took place at highstand lake level although the final form of the lithosome was heavily controlled by the fluctuations in lake level it depended on the relative proportions of gravel and silt sedimentation the gravel siltstone interface therefore represents an equilibrium surface between the proportions of sedimentation of these lithologies the bodies mentioned above are organized in coarsening and thickening upwards sequences tens of metres thick in which a distal to proximal evolution can be observed from isolated channels to lenses or from stacked channels to sheets the building and thickness of these sequences were controlled by fluctuations in the lake level an initial fall in base level caused lengthening of the channels and entrenchment from distal to proximal areas and a continuous increase in supply due to erosion in the drainage basin installed on the subaerial fan when the lake level rose lobes were formed at the channel endings and overbank processes were made possible thus generating radial channels whose levees were formed by amalgamation with the levees of the main lens channels at the same time sheets were formed in proximal areas where the available amount of sediment was greater

origin of polygonal fractures in sand uppermost navajo and page sandstones page arizona abstract polygonal fractures in eolian sandstones occur along the upper surface of the navajo sandstone and along four additional surfaces within the page sandstone near page arizona the polygons are largely rectangular and range from 1 to 6 m across most of the fractures are less than 1 5 m deep and fracture widths range from hairlines to tens of centimeters or more fracture fill most commonly shows vertical layering and in some cases a series of layers is evident symmetrical about the midline of the fracture other fractures are filled with contorted or structureless deposits subhorizontal laminae and displaced or brecciated host strata in some cases surfaces marked by polygonal fractures can be shown to have been topographically low at the time of deposition and the fracture sandstone below these low areas contains calcite or siliceous nodules and siliceous cement interpreted as contractional in origin the polygonal fractures formed on an exposed evaporite encrusted surface in a manner similar to ice wedges irregularities in these fractures are attributed to erosion by wind or water evaporites evidenced by anhydrite inclusions pore shapes megaquartz replacement and pseudomorphs of evaporitic minerals provided the cohesion and contraction that caused the tensional stresses necessary for polygonal fracturing stresses were the result of thermal contraction such surfaces are thought to represent hiatuses in eolian sand sea development and probably represent deflation to near the water table during net deflationary conditions

fluvial aeolian interactions part i modern systems two modern fluvial aeolian depositional systems great sand dunes national monument colorado and the mojave river wash california are remarkably similar in spite of different climates sizes fluvial sediment textures and relative directions of aeolian and fluvial transport dune growth and migration and deflation of blowouts create 8 10 m of local relief in unflooded aeolian landscapes there are six prominent fluvial aeolian interactions 1 fluvial flow extends into the aeolian system until it is dammed by aeolian landforms 2 interdune areas overbank interdunes upstream of aeolian dams and alongside channels are flooded 3 water erodes dunes alongside channels and interdunes 4 flood waters deposit sediment in interdune areas 5 fluvially derived groundwater floods interdunes interdune playas 6 wind erodes fluvial sediment and redeposits it in the aeolian system unique and characteristic sediments are deposited in overbank interdunes and in interdune playas reflecting alternate fluvial and aeolian processes and rapidly changing flow and salinity conditions these fluvial aeolian interdune deposits are characterized by irregular concave up bases and flat upper surfaces containing mudcracks or evaporite cement characteristic low relief surfaces form in aeolian systems as an effect of flooding fluvial deposits are resistant to aeolian deflation aeolian sand is preserved when flood sediments are deposited around the bases of the dunes thus repetitive fluvial and aeolian aggradation tends to be stepwise as interdune floors are suddenly raised during floods the effects of flooding should be easy to recognize in ancient aeolianites even beyond the area covered with overbank muds

stratigraphic analysis of eolian interactions with marine and fluvial deposits middle jurassic page sandstone and carmel formation colorado plateau u s a abstract the eolian page sandstone middle jurassic in south central utah and adjacent arizona consists of multiple mostly eolian sequences and sequence bounding unconformities super surfaces the super surfaces are a powerful correlation tool that provide the basis for a detailed regional stratigraphic analysis of the page sandstone and coeval parts of the marine and coastal plain carmel formation some page sandstone super surfaces correlate with sharp lithologic breaks in the carmel formation that are interpreted as marine flooding surfaces others correlate with fluvial surfaces in the carmel formation the lower part of the page carmel interval encompasses seven onlapping accumulation sequences bounded by marine flooding surfaces the uppermost two represent the middle jurassic marine high water mark these seven units comprise marine transgressive and marine highstand system tracts each interval is composed of progradational eolian deposits over marine deposits major tectonic and sedimentologic changes affected accumulation sequences 8 and 9 the two intervals are continental in origin fluvial to the west and eolian to the east a major slightly angular regional unconformity marks the top of accumulation sequence 9 the unconformity reflects regional tilting up to the northeast and ensuing erosion of older units in the page sandstone accumulation sequence 10 the top of the s udy interval displays complexly juxtaposed continental and marine facies that buried the unconformity as regional subsidence continued the broad patterns described above can be correlated with thick marine carbonate and minor siliciclastic deposits of the twin creek limestone 400 km north of the study area the resulting depositional patterns define three broad depositional events the oldest of these sequences defines a regional marine transgression and highstand the second sequence reflects strong siliciclastic influx and slight regional tilting that resulted in widespread continental deposition regional tilting and erosion closed out this event the youngest sequence indicates a partial return to marine transgressive conditions but was complicated by regional uplift and tilting related to are tectonism this study demonstrates that a sequence stratigraphic framework can be applied to sparsely fossiliferous eolian sabkha and restricted marine deposits in a marine coastal setting using detailed sedimentologic and stratigraphic studies tectonic eustatic and possibly climatic signals can be differentiated within the complex cyclic facies patterns displayed in the page sandstone and carmel formation

palaeomagnetic results from the fold and thrust belt of the western carpathians an overview the western carpathians are separated into an outer and inner carpathians both comprising several nappe systems by the extremely narrow and highly deformed pieniny klippen belt the main phase of deformation and thrusting took place during the late cretaceous in the inner carpathians at the end of cretaceous paleocene in the pieniny klippen belt and in the miocene in the outer carpathians in this paper a large amount of palaeomagnetic results of different quality available from several nappe stacks and from overstep sequences were reviewed and interpreted in terms of tectonics the data suggest that all three main units participated in two phases of anticlockwise rotation starting at 18 5 ma that is the outer carpathian nappes in front of the already consolidated alpine carpathian pannonian block became accreted to the block late cretaceous nappe transport neogene uplift of core mountains and possibly oroclinal bending of pre oligocene age can account for important differences in pre cenozoic palaeomagnetic declinations most of them exhibit less or no anticlockwise rotation suggested by the overstep sequences implying pre cenozoic clockwise rotations of variable angles

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

the bending model of the transdanubian central range hungary in the light of triassic palaeomagnetic data summary in the carpatho pannonian region the transdanubian central range is the second largest unit with changing strike along the sw ne trending mesozoic sequence this structure was tested palaeomagnetically for oroclinal bending with the help of triassic data most of them derived from widespread platform carbonates based on nearly 700 samples it was possible to obtain a statistically well defined overall mean palaeomagnetic direction for a werfenian early carnian age group in the western part of the range and a diverent direction for a late carnian rhaetian age group extending over the whole length of the range these two mean directions are d 316 i 38 k 70 a 95 8 n 9 and d 292 i 57 k 31 a 95 10 n 10 respectively the statistical parameters of these overall mean palaeomagnetic directions are comparable to those characterizing rigid areas nevertheless an attempt was made to correlate the tectonic trend and palaeomagnetic declination which lead to rejecting the model of oroclinal bending however it was possible to separate the late carnian rhaetian sampling

conical folds and apparent rotations in paleomagnetism a case study in the southern pyrenees abstract the so called apparent rotation was defined as the angular deviation between a local paleomagnetic direction after the standard bedding correction and their corresponding paleomagnetic reference j geophys res 85 1980 3659 in this paper we make a theoretical exploration on this concept and we conclude that depending on the number sequence orientation and magnitude of the deformation axes that have affected to the rock volume the apparent rotation may be the addition of a vertical axis rotation plus a spurious rotation the later is an error whose origin is the inappropriate application of the bedding correction during the restoration which does not fit the reverse sequence of deformations then apparent rot s l spurious rot vertical axis rot conical folds are complex geometries that cannot be restored by using the bedding correction however appearance of apparent and spurious rotations has not been studied even though the presence of this kind of folds is very common in fold and thrust belts in this paper we show a way to restore these structures and its associated paleomagnetic data by means of forward modelling on a stereographic projection the modelling has to be based on a good characterization of the geometry fold axis orientation and understanding of the kinematics of the fold general modelling has also allowed us to predict the apparent rotation in conical synclines its magnitude depends on the semiapical angle and on the degree of development of the fold the sense of the rotation clockwise or counter clockwise will depend on the sense of rotation the fold axis the western external sierras provide an excellent case study of apparent rotations due to the presence of a conical fold in the footwall ebro foreland basin of the south pyrenean sole thrust in addition a vertical axis clockwise rotation up to 47 32 in average has been detected in the hagingwall an apparent rotation up to 28 20 in average is observed in the footwall of the structure when a simple bedding correction is used this deviation does not fit with the expected ebro basin direction reference and is caused by the effect of the riglos conical syncline developed by the flexure of the foot wall ramp of the south pyrenean sole thrust the forward modelling carried out considering the geometry and kinematics non significant rotations in the autochthonous foot wall of this structure predicts very well the paleomagnetic observations in the field geographic coordinates with angular departures of only 5 in average the only application of the bedding correction would introduce errors spurious rotations up to 21 12 in average related to the conical geometry that would not allow the differentiation of these distinct structural 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

observed impact of atlantic sst anomalies on the north atlantic oscillation the large scale patterns of covariability between monthly sea surface temperature sst and 500 mb height anomalies z500 in the atlantic sector are investigated as a function of time lag in the ncep ncar reanalysis 1958 97 in agreement with previous studies the dominant signal is the atmospheric forcing of sst anomalies but statistically significant covariances are also found when sst leads z500 by several months in winter a panatlantic sst pattern precedes the north atlantic oscillation nao by up to 6 months such long lead time covariance is interpreted in the framework of the stochastic climate model reflecting the forcing of the nao by persistent atlantic sst anomalies a separate analysis of midlatitudes 208 708n and tropical 208s 208n sst anomalies reveals that the bulk of the nao signal comes from the midlatitudes a dipolar anomaly with warm sst southeast of newfoundland and cold sst to the northeast and southeast precedes a positive phase of the nao and it should provide a prediction of up to 15 of its monthly variance several months in advance since the forcing sst pattern projects significantly onto the tripole pattern generated by the nao these results indicate a positive feedback between the sst tripole and the nao with a strength of up to 25 mk 21 at 500 mb or 2 3 mb k21 at sea level additionally a warming of the tropical atlantic 208s 208n roughly symmetric about the equator induces a negative nao phase in early winter this tropical forcing of the nao is nearly uncorrelated with and weaker than that resulting from the midlatitudes and is associated with shorter lead times and reduced predictive skill

palaeogeographic evolution of the pieniny klippen basin using stratigraphic and palaeomagnetic data from the veliky kamenets section carpathians ukraine abstract a 40 m thick carbonate succession of the bajocian to berriasian age from the veliky kamenets quarry novoselica area pieniny klippen belt ukraine resembles both the czorsztyn and niedzica successions of the pieniny klippen belt traditionally considered ridge slope related deposits a total of 176 individually oriented cores collected from the bottom to the top of the sequence with sampling density dependent on inferred sedimentation rates show multicomponent remanent magnetization with magnetite as a main magnetic carrier thermal demagnetization revealed two main components of natural remanent magnetization nrm a low blocking temperature component s of normal polarity is considered of posttectonic probably thermoviscous origin due to overheating by neogene volcanics a stable high blocking temperature nrm component p shows dual polarity distribution and is considered primary it was possible to recognize 23 polarity zones that have been correlated with a biostratigraphic scale since two significant sedimentary gaps occur at 422 and 860 cm the main hiatus ms from the base the latter comprising the middle callovian early oxfordian time span 6 8 ma an obtained pattern of magnetic reversals presented in this study cannot be considered complete a palaeolatitude of 41 5 is calculated for the mid jurassic part below ms similar to that expected for the european craton at the kamenets locality the mid oxfordian limestone directly overlying the ms has palaeolatitudes around 28 6 this implies a relatively fast opening of the oceanic domain to the north from the kamenets block this conclusion combined with similarity of the kamenets sequence to ridge related sediments of the pieniny klippen belt makes it possible to speculate on the existence of the kamenets ridge a new term a structure of uncertain although possible structural links to the czorsztyn ridge palaeomagnetic declinations suggest 100 counterclockwise rotation of the whole section before the neogene

mesozoic palaeomagnetism of the transdanubian central mountains and its tectonic implications abstract the mesozoic apparent polar wandering apw of the transdanubian central mountains determined from thermally isolated natural remanences at 13 localities shows a remarkable similarity to the mesozoic apw of africa in that they both exhibit the same loop like movement moreover the difference between the two apw s can practically be eliminated by a 35 clockwise rotation of the palaeodeclinations it is concluded therefore that the region of the transdanubian central mountains was part of the african adriatic plate up to some time in the cenozoic when it moved to its present position resulting in a 35 anticlockwise rotation relative to africa

fluvial aeolian interactions part ii ancient systems an understanding of fluvial aeolian deposition derived from modern case examples in a previous study is applied to the permian cutler formation and cedar mesa sandstone on the colorado plateau these formations supply an excellent three dimensional exposure of intertonguing fluvial and aeolian strata four distinct facies associations form the bulk of the cutler formation and cedar mesa sandstone 1 aeolian dune deposits 2 wet interdune deposits 3 fluvial channel deposits and 4 overbank interdune deposits in addition two distinctive types of erosion surfaces are found within the cutler formation and cedar mesa sandstone pebble to granule rich erosion surfaces aeolian deflation surfaces and flood surfaces fluvial and aeolian intertonguing result in extensive tabular sheets of aeolian sandstone separated by flood surfaces and overbank interdune deposits fluvial channels are associated with the deposits overlying flood surfaces and are incised into the underlying aeolian sandstones overbank interdune deposits and wet interdune deposits cover flood surfaces and intertongue with overlying aeolian sandstones the primary characteristics of ancient fluvial aeolian deposition are overbank interdune deposits and pronounced extensive erosion surfaces flood surfaces which are parallel to underlying fluvial sandstones and thus trend parallel to the palaeoslope and palaeohydrological gradient

mesozoic plate tectonic reconstruction of the carpathian region abstract palaeomagnetic palaeobiogeographic and structural comparisons of different parts of the alpine carpathian region suggest that four terranes comprise this area the alcapa tisza dacia and adria terranes these terranes are composed of different mesozoic continental and oceanic fragments that were each assembled during a complex late jurassic cretaceous palaeogene history palaeomagnetic and tectonic data suggest that the carpathians are built up by two major oroclinal bends the alcapa bend has the meliata oceanic unit correlated with the dinaric vardar ophiolite in its core it is composed of the western carpathians eastern alps and southern alcapa units transdanubian range bukk this terrane finds its continuation in the high karst margin of the dinarides further elements of the alcapa terrane are thought to be derived from collided microcontinents czorsztyn in the n and a carbonate unit tisza in the se the tisza dacia bend has the vardar oceanic unit in its core it is composed of the bihor and getic microcontinents this terrane finds its continuation in the serbo macedonian massif of the balkans the bihor getic microcontinent originally laid east of the western carpathians and filled the present carpathian embayment in the late palaeozoic early mesozoic the vardar ocean occupied an intermediate position between the western carpathian austroalpine transdanubian high karst margin and the bihor getic serbo macedonian microcontinent the vardar and pindos oceans were opened in the heart of the mediterranean adriatic microcontinent in the late permian middle triassic vardar subducted by the end of jurassic causing the bihor getic serbo macedonian microcontinent to collide with the internal dinaric western carpathian margin an external penninic vahic ocean tract began opening in the early jurassic separating the austroalpine western carpathian microcontinent and its fauna from the european shelf further east the severin ceahlau magura also began opening in the early jurassic but final separation of the bihor getic ribbon and its fauna from the european shelf did not take place until the late middle jurassic the alcapa and the tisza dacia were bending during the albian maastrichtian the two oroclinal bends were finally opposed and pushed into the gates of the carpathian embayment during the palaeogene and neogene at that time the main n s shortening in distant alpine and hellenic sectors was linked by a broader right lateral shear zone along the former vardar suture

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

mesozoic paleogeography of the northern calcareous alps evidence from paleomagnetism and facies analysis the northern calcareous alps are generally thought to have been part of the same southern tethyan continental margin as the southern alps during late jurassic and early cretaceous time contrasting liassic paleomagnetic data from the northern calcareous alps and the southern alps can be explained by large scale clockwise rotation during late cretaceous and tertiary tectonic emplacement of the northern calcareous alps onto the european continental margin alternatively the data can be reconciled by postulating that the northern calcareous alps did not undergo the african mesozoic rotational history seen in the southern alps and were separated from the southern alps by a short lived branch of jurassic ocean facies analysis in the karwendel thiersee syncline of the northern calcareous alps indicates that the jurassic basin sediments in this area were deposited in an east west oriented sinistral strike slip fault system in the southern alps and central austroalpine complex coeval basin sedimentation was controlled by north south oriented normal faults this contrasting basin evolution and evidence for a source of ophiolitic detritus south of the northern calcareous alps argue for a short lived ocean basin south of the northern calcareous alps that was closed by early cretaceous time

the strontium isotopic composition and origin of burial cements in the lincolnshire limestone bajocian of central lincolnshire england strontium isotopic composition 87sr 86sr of two petrographically chemically and isotopically 18o and 13c distinct phases of burial calcites from the lincolnshire limestone are indistinguishable 0 70820 26 the mean 87sr 86sr ratio of these phases is considerably more radiogenic than 87sr 86sr ratios of bajocian marine waters 0 70725 neither bajocian marine waters nor meteoric waters buffered by host marine carbonate in the limestone could have precipitated the burial spars radiogenic strontium may have been contributed from k feldspar dissolution and or clay recrystallization either within clastic portions of the limestone itself or from major clastic units adjacent to the limestone alternatively palaeozoic marine waters or remobilized palaeozoic marine carbonate and or sulphate could have supplied the necessary radiogenic strontium

sequential architecture in a fluvial succession sequence stratigraphy in the upper cretaceous mesaverde group prince canyon utah abstract five unconformity bounded sequences have been documented within a 1300 m thick succession of predominantly fluvial upper cretaceous and lower tertiary deposits in the price canyon area of the westernmost part of the book cliffs east central utah u s a this area experienced major tectonically induced changes in the paleogeography during deposition the earliest fluvial deposits in the study area were formed in a relatively simple foreland basin setting in front of the sevier orogenic belt and contain more marine influence than previously recorded following a gradual termination of thrusting sedimentation became increasingly controlled by uplift of the san rafael swell to the southeast our studies suggest that the fluvial systems in the upper part of the succession alternated bet een being confined within a valley open towards the north and being more directly eastward flowing on the basis of the observed sequences an idealized model of alluvial sequences whose internal architecture can be related to a fall rise fall cycle of the stratigraphic base level has been established upward or downward changes in the position of this base level dictate the creation and destruction of accommodation on the alluvial plain and therefore exert a direct control on the sequential architecture and sandstone body geometry of fluvial successions in our model the basal sequence boundary is overlain by an amalgamated fluvial sandstone sheet the sheet is succeeded by a fining upward more mudstone rich level with more isolated sandstone bodies and this level may culminate in a marine or lacustrine transgression the upper part of the sequence may show a coarsening upward trend heralding the next phase of base level fall and sequence boundary generation use of the suggested model has the potential to refine existing lithostratigraphic schemes and given the higher resolution and more detailed correlation may significantly improve paleogeographic reconstructions and aid in prediction of potentially hydrocarbon bearing reservoirs a revised and refined lithostratigraphy has been established on the basis of alluvial sequence analysis the lower half of the succession forms the youngest part of a major eastward prograding clastic tongue the mesaverde group and is campanian we divide this part into the blackhawk castlegate and price river formations the rest of the succession is maastrichtian to paleocene and is referred to the north horn formation this formation was deposited in an intermontane setting

eolian sequence and erg dynamics the permian corrie sandstone scotland abstract a nearly 700 m thick sequence of permian erg deposits was preserved in a rapidly subsiding inland basin arran scotland the eolian sequence is composed of more than 30 superimposed erg units separated by erg order deflation super bounding surfaces each erg unit 6 to 72 m in thickness mean 22 m is initiated by flat bedded eolian sandstones 0 5 to 7 0 m in thickness mean 2 9 m of amalgamated interdraa or interdune origin and is topped by cross bedded draa or dune sandstones 3 to 70 m in thickness mean 18 m the eolian sequence represents alternating episodes of erg accumulation and erg deflation these alternating constructional and destructional phases are related to climatic oscillations determining sand supply to the erg system in the vertical dimension the erg units define six complete megacycles 62 to 184 m in thickness mean 110 m each of which is composed of four to six erg units basic cycles the origin of this composite cyclicity is viewed in the light of permian orbital climatic forcing and glacial cycles finally the dynamics of the corrie erg is compared to two permian coastal erg systems in north america

preservation of aeolian genetic units by lava flows in the lower cretaceous of the parana basin southern brazil the lower cretaceous geological record of the intracratonic parana basin in southern brazil comprises a thick succession of aeolian sandstones and volcanic rocks the intercalation between aeolian sandstone and volcanic floods allowed the preservation of distinct aeolian genetic units each genetic unit represents an accumulation episode bounded by supersurfaces that coincides with the base of lava flood events the entire package can be subdivided into a lower genetic unit which corresponds to aeolian sandstones preserved below the initial lava flows botucatu formation and an upper set of genetic units which comprises interlayered aeolian deposits and lava floods serra geral formation the lower genetic unit is up to 100 m thick its base is composed of ephemeral stream and aeolian sand sheet deposits that are overlain by cross bedded sandstones whose origin is ascribed to simple locally composite crescentic and complex linear aeolian dunes aeolian accumulation of the lower unit was possible as a result of the existence of a wide topographic basin which caused wind deceleration and a large sand availability that promoted a positive net sediment flux the upper genetic units comprise isolated sand bodies that occur in two different styles 1 thin lenses 3 m thick formed by aeolian sand sheets and 2 thick sand lenses 3 15 m comprising cross bedded cosets generated by migration and climbing of simple to locally composite crescentic aeolian dunes accumulation of the aeolian strata was associated with wind deceleration within depressions on the irregular upper surface of the lava floods the interruption of sedimentation in the lower and upper genetic units and related development of supersurfaces occurred as a result of widespread effusions of basaltic lava preservation of both wind rippled topset deposits of the aeolian dunes and pahoehoe lava imprints indicates that lava floods covered active aeolian dunes and hence protected the aeolian deposits from erosion thus preserving the genetic units

astronomical forcing of meandering river behaviour milankovitch cycles in devonian of east greenland abstract a more than 1100 m thick succession dominated by single and multistorey sandstone bodies from the upper devonian kap graah group in east greenland is interpreted as a meandering river and associated overbank deposits the sandstone bodies display well developed lateral accretion bedding and are interpreted to be deposited as point bars in a well exposed section 215 m thick individual sandstone bodies have been analized quantitatively in order to compare the individual palaeochannel characteristics the results indicate cyclic variations in discharge channel slope and channel size the cycles are of the order of c 20 m thick with superimposed c 100 m mega cycles both are interpreted as reflecting cyclic variations in precipitation rate the cycles are interpreted as being governed by astronomical forcing of the climate reflecting milankovitch type precession cycles in the order of 20 000 years with modulation by c 110 000 years eccentricity mega cycles this study confirms that the precession and eccentricity cycles exhibit the main forcing on low latitude monsoonal climate

gulf stream variability and ocean atmosphere interactions abstract time series of gulf stream position derived from the topex poseidon altimeter from october 1992 to november 1998 are used to investigate the lead and lag relation between the gulf stream path as it leaves the continental shelf and the changes in sea level pressure surface wind stress and sea surface temperature sst as given by the ncep reanalysis the dominant signal is a northward southward displacement of gulf stream axis 11 to 18 months after the north atlantic oscillation nao reaches positive negative extrema a sst warming cooling peaking north of the gulf stream is also seen to precede the latitudinal shifts but it is a part of the large scale sst anomaly tripole that is generated by the nao fluctuations there is no evidence that the gulf stream shifts have a direct impact onto the large scale atmospheric circulation a fast passive response of the gulf stream to nao forcing is also suggested by a corresponding analysis of the yearly mean gulf stream position estimated from

paleomagnetism and paleogeography of the northern calcareous alps austria prefolding magnetization components have been resolved at 38 sites of liassic adnet limestones in the central northern calcareous alps nca and at one site in the drauzug the site mean directions are northeasterly and down and are closer to coeval european directions than to southern alpine african directions the western end of both the nca and of the drauzug yield different site mean directions and negative fold tests indicating remagnetization the sampling localities have been rotated relative to one another during thrusting however comparison of paleomagnetic poles with the european apparent polar wander path implies an average clockwise rotation of about 30 for the nca relative to europe larger scale clockwise rotations in excess of 80 relative to the southern alps are implied by comparison with the southern alpine african polar wander path facies analysis of jurassic and lower cretaceous basinal sediments in the central part of the nca suggests that liassic subsidence was related to presently e w sinistral strike slip faults whereas malm berriasian subsidence was controlled by presently e w south dipping normal faults both paleomagnetic and facies data tend to indicate that the nca did not undergo the african rotation seen in southern alpine paleomagnetic data this implies the existence of a short lived tract of triassic jurassic ocean floor between the nca and the southern alps which linked the pindos ocean to the ligurian trough and allowed adria to rotate independently from the nca during the late jurassic eo alpine deformation and metamorphism are associated with the early cretaceous closure of this hallstatt trough

sand drift surfaces a neglected type of bounding surface sand drift surfaces are sharp generally erosional surfaces separating waterlaid deposits from overlying eolian sand sheet deposits they form in many modern playa lake ephemeral stream and alluvial fan environments but have rarely been reported from ancient sequences sand drift surfaces are an important type of bounding surface one which marks the transition from subaqueous to eolian depositional processes thereby providing valuable information for environmental reconstructions architectural element analysis and short and long term climate changes because of their nature sand drift surfaces cannot be described by existing bounding surface classifications to overcome some of the classification problems we suggest a simple nonhierarchical terminology

new berriasian palaeopole from the central west carpathians tatra mountains southern poland does it look apulian summary a palaeomagnetic study was carried out in the northern part of the central west carpathians in the tatra mts 20 e 49 n berriasian pelagic carbonates from the krizna nappe fatricum were investigated at three localities 166 samples embracing a 100 m vertical section a mixed polarity pre folding magnetite related component was calculated for 87 samples representing the lower and middle berriasian the palaeopole 152 e 63 n is located close to the coeval eurasian palaeopole implying a net post berriasian 15 20 clockwise tectonic rotation of the krizna nappe in the investigated area relative to stable europe berriasian palaeolatitudes from the tatra mts are similar to those from the pieniny klippen belt and northern calcareous alps but systematically higher than in the transdanubian and italian apulian sections taking into account the fact that palaeomagnetic data from the overlying ter tiary rocks indicate 60 counter clockwise rotation of the central west carpathians after the oligocene the krizna nappe must have rotated clockwise before the eocene probably during the late cretaceous thrusting available palaeomagnetic data point to a palaeotectonic affinity of the central west carpathi ans and northern calcareous alps in the mesozoic the central west carpathians and northern calcareous alps reveal a rotation pattern that is predominantly clockwise whereas areas be longing to the apulian plate e g transdanubian mts southern alps and appenines show mostly counter clockwise rotations

sequence stratigraphy and orbital forcing in permian rotliegend desert deposits a discussion rotliegend sequence stratigraphy in the southern permian basin suggests climatically forced fluctuations in the level of an expanding playa lake system the associated facies changes are abrupt and define essentially isochronous sequence boundaries spectral analyses of gamma ray logs have indicated that individual sequences display internal cyclicity consistent with orbital milankovitch forcing confirmatory results have been reported from the spectral analysis of field logs from the continental permian brodick beds of the isle of arran these studies claim that since the cycles are orbitally forced they have chronostratigraphic significance however they are based on dubious assumptions concerning the unvarying rate and continuity of deposition of the sequences in question in the case of the southern permian basin the assumption is applied to c 50 m units but the result is an implausible chronostratigraphic model for the brodick beds the assumption is applied to a 675 m succession and there is a crucial ambiguity in the relationship between the lithostratigraphic cycles and the permian orbital cycles the studies do not provide persuasive evidence of the consistent encoding of milankovitch orbital cycles in permian desert deposits

conditions favourable for the formation of warm climate aeolian sand sheets aeolian sand sheets are areas of aeolian sand where dunes with slipfaces are generally absent sand sheets are ubiquitous to modern warm climate sand seas generally occurring marginal to dune fields although they may exist within the interior of a sand sea or independent of a dune field sand sheet deposits are recognized in ancient aeolian sequences where they may account for significant accumulations of low angle aeolian stratification we suggest that the occurrence of sand sheets instead of dunes indicates that conditions are outside the range within which dunes form or that one or more factors interfere with dune development while also favouring the accumulation of sand sheets a study of six modern sand sheets in north america located at great sand dunes gran desierto dumont algodones padre island and colorado river delta indicates that the factors favourable for sand sheet development are 1 a high water table 2 surface cementation or binding 3 periodic flooding 4 a significant coarse grained sediment population and 5 vegetation these factors are reflected in the nature of stratification and the accessory features of sand sheet accumulations within the areas of modern sand sheets as well as in their ancient counterparts in the triassic dolores and pennsylvanian permian rico formations

paleomagnetic implications on the evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we first re examined the apparent polar wander curves for stable eurasia and africa since the triassic these curves were then combined together with curves of north and south america according to the kinematics of the atlantic ocean and a synthetic polar wander curve was given then most of the paleomagnetic results from the tethys mobile belt from the atlantic to the pamirs were analysed several groups of plates microplates and blocks can be seen first relatively stable regions like maghreb and sicily which have not moved much then we have a group formed by iberia sardinia italy and to a lesser extent corsica and the western and central alps for these blocks movements are anticlockwise rotations chiefly driven by the anticlockwise rotation of africa but they are sometimes stronger to the east a major change takes place the north of the aegean sea and the ionian zone are clockwise rotated and these rotations are recent oligocene miocene for the first part pliocene to the present for the second part a major problem arises in turkey caucasus and iran paleomagnetic results indicate a position far to the south of eurasia and at the same time geological evidence is in favour of a position close to eurasia we discuss these discrepancies

the signature of the midlatitude tropospheric storm tracks in the surface winds abstract storm track analysis is applied to the meridional winds at 10 m and 850 hpa for the winters of 1999 2006 the analysis is focused on the north atlantic and north pacific ocean basins and the southern ocean spanning the region south of the indian ocean the spatial patterns that emerge from the analysis of the 850 hpa winds are the typical free tropospheric storm tracks the spatial patterns that emerge from the analysis of the surface winds differ from the free tropospheric storm tracks the spatial differences between the surface and free tropospheric storm tracks can be explained by the influence of the spatial variability in the instability of the atmospheric boundary layer strongly unstable boundary layers allow greater downward mixing of free tropospheric momentum momentum mixing and this may be the cause of the stronger surface storm tracks in regions with greater instability in the time mean principal component analysis suggests that the basin scale variability that is reflected in th

escape models of the alpine carpathian pannonian region in the light of palaeomagnetic observations recent tectonic models of the alpine carpatho pannonian region alcapa assume a large eastward shift of the transdanubian range domain in the cenozoic since palaeomagnetism is one of the most powerful tools in solving geodynamic processes the authors present an approach to the escape problem by using all available and relevant palaeomagnetic data this data set demonstrates consistency with models put forward by geologists for jurassic and older ages from the mid jurassic on the northern calcareous alps nca did not share the rotations of the transdanubian range domain and of the southern alps after individual movements from neocomian to miocene the transdanubian range domain must have drifted northward in the mid miocene up to the southern margin of the northern calcareous alps before starting the escape in the geologists definition

perspectives on the sequence stratigraphy of continental strata this report is the result of a working group on continental sequence stratigraphy that was set up at the 1991 nuna conference in banff canada to date sequence stratigraphic concepts have been applied mainly to the marine realm but unconformity bounded units have long been recognized in nonmarine strata successful application of sequence stratigraphic concepts to continental strata requires careful consideration of controls on base level and sediment supply as with shallow marine environments relative sea level can be considered as the stratigraphic as well as the geomorphic base level for coastal nonmarine settings farther inland stratigraphic base level which determines accommodation space is more complex and takes various forms such as the graded profile for fluvial strata groundwater tables for some eolian strata and lake level for some intermontane sediments sediment supply is also generally a more complex variable for nonmarine environments than in the marine realm because of the proximity to the source area the influence of climate and tectonism on sediment supply can clearly be seen in many continental sediments the fact that the major controls of climate tectonism and eustasy are somewhat interdependent and that a change in one parameter will most likely be reflected in others is also more readily apparent in continental strata although in its infancy sequence stratigraphic concepts have been applied to a wide variety of continental settings in attempts to explain variations in facies architecture of particular interest are studies that have linked fluvial architecture on coastal plains to variations in relative sea level as indicated by coeval marine strata and studies of lacustrine environments that show marked variation in facies between highstand and lowstand deposits the application of sequence stratigraphy to continental strata will likely result in the development of better correlation techniques and models that better predict the location and nature of fluvial and eolian reservoirs

aeolian stratification and facies association in desert sediments arran basin permian scotland abstract permian aeolian sediments on the island of arran are divisible into dune including draa and interdune deposits both types display a distinctive and unusually wide variation in grain size the dominant features of the dune deposits are grainfall lamination sandflow lamination and inverse graded lamination associated with ripple form lamination and normal graded lamination the flat lying aeolian interdune deposits are characterised by granule and sand ripples horizontal lamination in coarse sand and granules plane bed lamination and inverse graded lamination associated structures include ripple form lamination and deflation lags three types of trace fossil associated with completely bioturbated horizons occur in some low angle dune and interdune deposits the aeolian facies interfinger with alluvial fan deposits giving rise to three recognizable facies belts marginal aeolian deposits are associated with fluvial conglomerates and are dominated by interdune deposits and occasionally very thin barchan deposits set height 3 37 cm intermediate aeolian deposits are characterized by interbedded crescentic dune small draa dune set height 5 cm 4 5 m and interdune deposits and rare fluvial and lake sediments basinal aeolian deposits are dominated by draa deposits dune set height 0 2 28 m associated with rare interdune sediments transverse dunes and draas were moved by north eastern palaeowinds towards the foot of the alluvial fans the aeolian sediments were deposited in a fault bounded desert basin

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

thermal history of the carnic alps southern alps austria and its palaeogeographic implications abstract the thermal history of the carnic alps southern alps austria has been investigated by means of organic petrology clay mineralogy and microthermometry in the tectonic framework of the carnic alps the metamorphic overprint from the lower anchizone up to the epizone is exposed in a continuous n s trending metamorphic section the metamorphic zonation is disturbed by shear zones related to the strike slip movement of the periadriatic lineament all obtained data a methodical correlation and a numeric 1d simulation of the burial history result in the model of a multistage thermal history 1 a variscan tectonothermal event caused a syntectonic anchi to epizonal metamorphism with the development of local overpressured zones characterized by convective heat transfer 2 major strike slip faults operating during the sedimentation of the late carboniferous molasse are related to enhance the heat flow 3 the alpine metamorphic overprint shows the same intensity as the variscan event 4 high temperature fluid inclusion phases are related to oligocene plutonic activity along the periadriatic lineament these data from the carnic alps are discussed in a general framework of the non to low grade metamorphic units of the internal alps and carpathians in the uppermost tectonic units of the eastern and southern alps a spatial and temporal shift of the alpine very low grade metamorphic overprint from north to south is observed this zonation indicates the pannonian transdanubian range which suffered no alpine metamorphism as an exotic block inside an alpine heated domain the gailtal line as a segment of the periadriatic lineament separates two terrains with the same alpine overprint

sea surface temperature anomalies planetary waves and air sea feedback in the middle latitudes the mechanisms that contribute to the generation and damping of large scale mid latitude sea surface temperature sst anomalies are discussed the sst anomalies reflect primarily the response of the upper ocean to the changes in air sea fluxes that are associated with daily weather fluctuations heat flux forcing is dominant in the lower middle latitudes while wind driven entrainment may be most effective in the high latitudes advection by anomalous ekman current is generally less important and ekman pumping is negligible the sst anomalies decay in part because of entrainment effects associated with mixed layer deepening and oceanic mixing and in part because of heat exchanges with the atmosphere the three approaches commonly used to model the evolution of sst anomalies are reviewed case studies based on monthly or seasonal anomaly maps of the large scale sst and atmospheric anomalies numerical simulations with one dimensional mixed layer models and stochastic forcing models we stress the similarities in the different approaches and discuss their main advantages and limitations the response of the atmosphere to mid latitude sst anomalies is considered first we discuss the poorly known relationship between sst anomalies and diabatic heating using a crude assumption for the air sea coupling we consider a two layer quasi geostrophic channel model and discuss the stationary wave response to sst anomaly forcing and the resulting air sea feedback it is found that the back interaction of the sst anomalies onto the atmosphere causes a weak sst anomaly damping at large scales and a strong one at small scales the air sea coupling should also act as an eastward propagator for the sst anomalies the response of more realistic linear wave models to prescribed diabatic heating is then reviewed and it is suggested that realistic mid latitude sst anomalies have a weak influence on the atmospheric circulation corresponding to changes in the geopotential height of 10 30 m at most this order of magnitude is consistent with the results of general circulation model experiments and with the limited climate predictability associated with mid latitude sst anomalies

spatial patterns of atmosphere ocean interaction in the northern winter abstract the variability of monthly mean sea surface temperature sst anomalies over the extratropical north atlantic and pacific and its relation to atmospheric circulation anomalies over the northern hemisphere during wintertime is investigated by applying eigenvector analysis to a 39 year dataset and correlating the time series of the resulting expansion coefficients with the hemispheric 500 mb height and sea level pressure fields in agreement with previous studies the simultaneous correlation between the tone series of the expansion coefficient of the first empirical orthogonal function eof 1 of north pacific sea surface temperature sst and the hemispheric 500 mb height field resembles the pacific north american pattern and the corresponding pattern for atlantic sst resembles the north atlantic oscillation in the vicinity of the conters of action of thew patterns the sst fluctuations associated with these modes explain on the order of half the variance of 500 mb height and slightly less of

record of palaeoenvironmental changes in a lower permian organic rich lacustrine succession integrated sedimentological and geochemical study of the rudnik member krkonose piedmont basin czech republic abstract this study presents an integrated sedimentological and geochemical analysis of the lower permian rudnik member the most extensive lacustrine deposits in the krkonose piedmont basin grey to black and variegated lacustrine mudstones laminites and carbonates of the rudnik member have a lateral extent of more than 400 km 2 in the studied sections four facies associations were recognised a anoxic offshore b suboxic to oxic offshore c nearshore and mudflat and d slope deposits in the northern part of the e w elongated basin anoxic to suboxic organic rich offshore lacustrine facies dominate and form a succession up to 130 m thick fan delta and turbidite facies occur locally along the faulted northern basin margin the central part of the basin is occupied by anoxic to oxic offshore facies interfingering with nearshore carbonate and mudflat facies of the low gradient lacustrine margin in the central part of the basin the thickness of the lacustrine deposits of the rudnik member reaches up to 60 70 m in the southern part of the basin fluvial and alluvial plain facies dominate and alternate with minor lacustrine nearshore facies the lateral facies distribution indicates that subsidence along the northern basin fault was the main mechanism generating the asymmetric infill geometry in the basin s half graben setting the 1 8 o values of primary and early diagenetic calcite range between 11 0 and 1 3 v pdb and 1 3 c values between 5 1 and 3 7 most of the data fall within the range of freshwater limestones coarser grained pure microspar laminae show more positive 1 3 c values in comparison to clayey organic rich micrite laminae and are interpreted as a record of bioinduced precipitation during seasonal eutrophication the obtained 1 3 c toc values range from 29 0 to 24 0 the total organic carbon toc content from 0 26 to 23 maceral analysis and rock eval pyrolysis indicate that most of the samples contain a mixture of aquatic and terrestrial organic matter but two minor distinctive groups of samples with algally dominated and terrestrially dominated organic matter composition respectively were also found the study of vertical changes in boron content in the clay fraction of the lacustrine mudstones shows that high lake level stages were periods of lower salinity with the lowest boron contents from 73 to 268 ppm and periods of falling lake level were followed by significant increases in salinity with much higher boron values 293 603 ppm lake level fluctuations of the rudnik lacustrine system which are recorded by shallowing up units of sedimentary facies within most of the sections throughout the basin can also be traced within the monotonous black shale dominated sections where no sedimentological evidence of these lake level changes exists good indicators for such changes seem to be the 1 8 o and 1 3 c values of primary calcite 1 3 c toc and hi these lake level fluctuations are interpreted as driven by climatic oscillations in the order of tens of thousands years which could reflect climatic changes connected with the last glaciation event of gondwana