formation and age of sphalerite mineralization in carbonate rocks of bajocian age in the swiss jura mountains evidence of mesozoic hydrothermal activity a combination of petrographic and geochemical techniques was applied to better constrain the origin and evolution of the fluid systems responsible for the formation of disseminated cd rich up to 0 6 wt sphalerite zns mineralization in the northeastern part of the jura mountains switzerland the rb sr ages of sphalerite samples indicate that a main phase of sphalerite formation occurred near the boundary between the late middle and early late jurassic at around 162 ma the negative 34s values 22 3 to 5 3 suggest that biogenic sulfide sulfur was involved in zns precipitation the strontium isotope composition is more radiogenic than that of contemporaneous seawater reflecting the interaction of mineralizing fluids with silicate rocks lead isotope signatures are very uniform 206pb 204pb 18 63 18 67 207pb 204pb 15 63 15 64 208pb 204pb 38 51 38 63 indicating an isotopically well homogenized fluid system the basement rocks underlying the jurassic strata are considered to be the main source of metals for the sphalerite mineralization the migration of deep sourced hydrothermal saline metal bearing fluids into the bajocian host carbonates containing sedimentary reduced sulfur resulted in the precipitation of sulfides the period of sphalerite formation near the middle late jurassic boundary is characterized by enhanced tectonic and hydrothermal activity in europe related to the opening of the central atlantic and tectonic thermal subsidence during spreading of the alpine tethys our study provides evidence that the bajocian carbonate rocks in the jura mountains area were affected by the circulation of deep sourced metal bearing hydrothermal fluids in response to these continent wide tectonothermal events the presence of sphalerite mineralization and associated geochemical anomalies in zn and cd contents in carbonate rocks may also be used to trace basement features

the eastern jura relations between thin skinned and basement tectonics local and regional the thesis area of hans cloos in the eastern jura straddles the boundary between the paleogene structures of the tabular jura a part of the southeastern end of the rhine graben and the neogene folds and thrusts of the folded jura a recent reflection seismic survey in the area adjacent to the east provides new information on the subsurface structure and the relation between three superposed tectonic events the main boundary fault zones of a deep and complexly faulted late paleozoic trough trending ene were reactivated in the early tertiary faulted flexures and small folds rooted in the basement and paleozoic with an amplitude of usually 100 to 300 m were produced rather than the normal faults typical for the extensional fields of the rhine bresse graben system in the west and the bavarian molasse basin in the east this suggests their being part of a transform zone between these extensional fields during jura decollement in the neogene these inherited deeply rooted sub decollement structures remained passive their small size is kinematically incompatible with the intense subsequent thrusting and folding of the thin mesozoic tertiary skin however thrust ramps were apparently nucleated at the respective southern foot of these paleogene flexures and folds the best defined and simplest of these composite structures is the mandach structure within the tabular jura a south facing flexure of about 300 m relief developed in the paleogene by reactivation of the northern border fault zone of the paleozoic trough in the neogene a north vergent decollement thrust which is connected with the regional jura decollement in the middle triassic evaporites was initiated at its site

modelling the generation of gravity waves by a maritime continent thunderstorm observed wind and temperature profiles are used to initialize a model calculation of a maritime continent thunderstorm and the numerical solution is used to explore the effect of tropospheric shear on the gravity wave generation the resultant convective system is qualitatively similar to that observed the modelled gravity waves propagate away from the cloud with wave fronts that are approximately circular implying that the convective clouds do not generate waves which propagate in a preferred direction the gravity wave generation is related to the oscillation of the convective updraughts about their level of neutral buoyancy while the general features of the gravity waves are similar in most respects to a previous study which used an idealized wind profile the frequency of the gravity waves is doppler shifted by the tropospheric wind shear the result is a much broader power spectrum in comparison to the idealized cases

variscan tectonics of central europe postaccretionary intraplate deformation of weak continental lithosphere the area occupied by the variscan belt of central europe forms part of gondwana derived microplates essentially avalonia and armorica that according to paleomagnetic data juxtaposed baltica and laurentia from the upper ordovician to the lower devonian the actual structure of this area is a puzzle of rather small fault bounded crustal blocks different in p t t histories which was created by later tectonic processes at around 360 to 320 ma according to a common view and by contrast to paleomagnetic data the structural record of fault bounded blocks is interpreted in terms of mid devonian to lower carboniferous amalgamation of narrow continental plates represented by the fault bounded blocks themselves however this is not supported in this article instead it will be shown that fault systems and fault bounded blocks were created by intraplate deformation of a weak domain of gondwana derived continental lithosphere significantly after its accretion deformation was partitioned into newly formed deep seated strike slip and kinematically connected reverse or normal detachment systems large translation magnitudes caused juxtaposition of crustal areas of variable thickness until they were emplaced along the fault systems the various categories of fault bounded complexes record different tectonic events category 1 metamorphic complexes represent deep seated parts of thickened crust some time before unroofing on the detachment systems between about 340 360 and 320 ma however the record of subduction and extreme crustal thickening during earlier stages of the collision history was erased to a high degree and is only preserved by mineral and structural relics strike slip and detachment systems propagated across and dismembered tectonic boundaries formed during these early events category 2 metamorphic complexes and the barrandian basin recording predominant pre late devonian metamorphic or stratigraphic events represent the brittle upper crustal parts during continuing metamorphism in the category 1 complexes weakly or unmetamorphosed lower paleozoic category 3 basins represent areas of thinned continental crust and record subsidence before and to some degree during activity of detachment systems the complex overall kinematic pattern of block bounding strike slip and detachment systems indicates compression and extension acting simultaneously this probably reflects the effects of continuing oblique plate convergence rotation and wsw extrusion of fault bounded blocks in addition to heating and extensional flow of previously thickened crustal areas

imaging the structure of a large scale tid using isr and tec data 1 here we present north american observations of the 3 dimensional structure of large scale traveling ionospheric disturbances tids that affected the low and mid latitude ionosphere during the stormtime period of october 1 2 2002 using tec data from the american network of dual frequency gps receivers we are able to examine the effect of the tids on the background tec and thus image their horizontal scales incoherent scatter radar data from the arecibo observatory give information on the vertical structure of the disturbances the meridional and zonal structure of the tids are explored by computing the tec perturbation a method which has a resolution of a fraction of a tec unit the technique is effective in mapping the global structure of large scale disturbances as the lower latitude perturbations can be examined at the same time as the higher latitude sources the method may prove valuable in studying the formation and propagation of tids

response of shallow marine carbonate facies to third order and high frequency sea level fluctuations hauptrogenstein formation northern switzerland abstract facies patterns in shallow marine carbonates of the hauptrogenstein formation of northern switzerland middle bajocian to early bathonian reflect small changes in sea level third order sea level fluctuations calculated from large scale facies patterns alternations of marl and carbonate dominated sedimentary units on the level of members and subsidence show two phases of sea level rise and fall in the late bajocian and a relative sea level rise in the early bathonian most of the sedimentary rocks were produced during phases of relative rise and highstand of sea level no periods of emergence during lowstands are preserved sea level changes of a higher order have been analyzed by facies changes at the outcrop scale thin shallowing up parasequences 0 5 6 m thick have been correlated across platform ramp and offshore sedimentary environments in each of these environments carbonates react differently to sea level fluctuations relative rises in sea level are represented by non deposition and biogenic sediments periods of stable or slightly falling sea level are dominated by oolitic sediments 1 in the offshoal environment marl layers at the base of thin shallowing up units are covered by increasingly proximal tempestites 2 in the ramp environment oblique stratified oolitic and bioclastic grainstones are bounded by marine flooding surfaces 3 on the platform marine flooding surfaces are overlain by beds deposited under moderate energy conditions coral beds oncoid beds platform tempestites which are in turn covered by high energy oblique stratified oolitic grainstones such parasequences deposited in response to small scale high frequency sea level changes can be correlated over distances of more than 100 km a model for evolution and response of carbonate facies to sea level changes is presented

the continental margin of the mesozoic tethys in the western alps abstract most of the structural units of the western alps were derived from the european continental margin of the ligurian ocean a segment of the mesozoic tethys ocean their mesozoic palaeotectonic and stratigraphic evolution bears witness of the following main stages 1 deposition of the triassic platform carbonates essentially prerift but nevertheless bearing the imprint of some extensional movements 2 the liassic middle jurassic rifting corresponds to the creation of a horst and graben system with especially tilted blocks and hence a shoal and basin palaeogeography but without a preliminary doming event 3 the late jurassic early cretaceous opening and spreading of the ligurian ocean began with a general collapse of the continental margin thermal subsidence latest middle jurassic and earliest late jurassic in this paper emphasis is given to the refting derived structures more especially to the major tilted crustal blocks a few tens of kilometres wide which can be either reconstructed or directly observed the rifting stage lasted roughly 40 m y with the alternation of extensional tectonic phases and of relatively quiet periods during the extensional phases movements along fault planes and related episodes of tilting were followed by sudden and rapid episodes of subsidence the latter may be interpreted as resulting from the isostatic and thermal readjustment that follows a phase of stretching of the crust and of the lithosphere the tectonic evolution of the margin continued but decreased during the late jurassic early cretaceous oceanspreading stage tectonic activity resumed in the late cretaceous this probably resulting from the beginning of contraction of both the ocean and the continental margin leading progressively to the continental collision in the tertiary

sea water circulation on an oolite dominated carbonate system in an epeiric sea middle jurassic switzerland the middle jurassic burgundy carbonate platform occupied a central part of the central european epeiric sea during the middle jurassic the facies architecture of the oolitic calcarenite bodies was affected by tidal currents on the platform and relative sea level changes the 13c values of inorganic carbonates sampled in biostratigraphic defined intervals do not match very well between closely spaced sections and hence are of restricted use for stratigraphic purposes it appears that the platform interior might have been decoupled from the global carbon pool although deposited in a rapidly accumulating setting the recorded isotope signatures might be affected by some local stratigraphic gaps nonetheless the carbon isotope data imply lateral changes of the platform waters these appear to be related to the position on the platform and to the sediment dispersal pattern as evidenced by clay minerals adjacent to the eastern margin of the platform detrital chlorite and illite occur in considerable proportions both ascribed to a boreal source to the east and the north east in contrast smectite rich mixed layer clay mineral content increases significantly towards the platform interior pointing to a delivery from the north west all these data are suggestive of an overall clockwise current pattern in the central european epeiric sea during the middle jurassic

reactivated basement structures affecting the sedimentary facies in a tectonically quiescent epicontinental basin an example from nw switzerland abstract the jurassic deposits in the southern part of central europe accumulated in a shallow epicontinental sea and their deposition has usually been believed to have corresponded to a phase of tectonic quiescence neither on conventional seismic records nor in outcrops obvious indications of synsedimentary tectonics were found nonetheless subtle variations in lithofacies and thickness occur above faults in the crystalline basement in fact preexisting structures became reactivated in the jurassic during major extensional phases when the tethys and the north atlantic opened this reactivation led to differential subsidence and or to rotation of fault bounded blocks but the sediments were deformed mainly flexurally as vertical movements in the basement were dissipated by triassic salt thus the depositional area was morphologically differentiated into swells and depressions in siliciclastic muddy environments swells were characterized by hardbottoms and hiatus beds depressions were filled by distal tempestites and gravity deposits in carbonate settings reefs nucleated on swells marls and muds were deposited in depressions many of them gravity deposits reactivation of faults occurred only during short episodes and was not synchronous throughout the study area and reactivation of individual faults was episodic and probably controlled by the palaeostress field and the faults orientation reactivation of deep rooted faults is also documented by hydrothermal activity which led to vein mineralization and alteration of minerals today exposed in nearby basement units the chronostratigraphic ages of the hydrothermal processes coincide with phases of enhanced subsidence during the sinemurian aalenian bajocian bathonian and oxfordian in turn facies changes of the sedimentary cover should be useful to predict basement structures when no seismic records are available

convectively generated mesoscale gravity waves simulated throughout the middle atmosphere 1 a three dimensional simulation was conducted with a cloud resolving model to investigate mesoscale gravity waves generated by cumulus convection that propagate to the mesospheric and lower thermospheric mlt region it is found that both individual convective turrets and mesoscale convective systems excite gravity waves resulting in a broad scale distribution waves excited by the former have conically shaped phase surfaces as previously reported and are conspicuous up to around the stratopause waves excited by the latter dominate in the mlt region frequent wave breaking is found above 85 km where convective instability is found typically in the initial stage leading to unstable shear with billows resembling the ripple type structures observed frequently in airglow imaging

reliability of k ar dating of clays and silicifications associated with vein mineralizations in western europe k ar ages were determined on fine fractions and one massive silicification associated with vein mineralizations in uranium barium fluorine and related base metals in western europe the reliability of the potassic materials analysed once the mineralogical and geochemical relationships to the low temperature mineralization have been established is demonstrated the isotopic ages are concentrated between nearly 190 and 170 ma this epoch corresponds to that of the rifting of the future atlantic and tethys oceans this type of low temperature mineralization thus seems to be better explained by extensional phenomena

tectonics of the central swiss molasse basin post miocene transition to incipient thick skinned tectonics in this paper we investigate the tectonics of the central swiss molasse basin smb situated between the central european alps and the jura fold and thrust belt based on re interpreted 2d reflection seismic data and geological 3d modeling we present new insights into the structural configuration and evolution of the central smb during the thin skinned main deformation phase of the jura fold and thrust belt 12 4 ma the central smb was riding passively above a major detachment horizon within triassic evaporites which roots beneath the external crystalline massifs of the central alps in the smb low amplitude detachment folds and detachment rooted wsw ene striking thrust and reverse faults are related to this event younger major nne ssw and nnw sse trending strike slip fault zones cross the basin over a length of several kilometers affecting the cenozoic and mesozoic cover units and extending into the pre mesozoic crystalline basement in cases the fault zones apparently reactivate inherited permo carboniferous trough pct bounding paleozoic normal faults seismic data further reveals mild inversion of wsw ene striking pcts these structures clearly cut the basement cover contact thus postdating the main deformation phase of the jura fold and thrust belt present day earthquake focal mechanisms and epicenter distribution show strike slip faulting and basement seated seismicity respectively thus corroborating our observations from seismic interpretation our data suggests a change from late miocene thin skinned to pliocene to present day incipient thick skinned tectonics this major change reflects the establishment of a mid crustal detachment and may be related to changes in slab dynamics of the subducting european lithosphere

low temperature thermochronology of the flanks of the southern upper rhine graben the upper rhine graben urg is the most perceptible part of the european cenozoic rift system uplifted variscan basement of the black forest and the vosges forms the flanks of the southern part of the graben apatite and zircon fission track ft analyses indicate a complex low temperature thermal history of the basement that was deciphered by inverse modelling of ft parameters the models were tested against the observed data and independent geological constraints the zircon ft ages of 28 outcrop samples taken along an e w trending transect across the black forest and the vosges range from 136 to 312 ma the apatite ft ages from 20 to 83 ma the frequency distributions of confined track lengths are broad and often bimodal in shape indicating a complex thermal history cooling below 120 c in the early cretaceous to palaeogene was followed by a discrete heating episode during the late eocene and subsequent cooling to surface temperature the modelled time temperature t t paths point to a total denudation of the flanks of urg in the range of 1 0 1 7 km for a paleogeothermal gradient of 60 c km and 1 3 2 2 km for a paleogeothermal gradient of 45 c km since the late eocene

long distance correlations by sequence stratigraphy and cyclostratigraphy examples and implications oxfordian from the swiss jura spain and normandy the oxfordian sedimentary successions studied in the swiss jura in normandy and in the soria and cazorla regions of spain display complex facies evolution and stacking patterns based on bio stratigraphy and absolute age dating it is suggested that the shallow water depositional settings in the jura normandy and the soria region as well as the deeper water environments in the cazorla region recorded climatic and sea level fluctuations in the milankovitch frequency band beds and bedsets corresponding to 20 100 and 400 ka cyclicities can be identified facies evolution inside such small scale sequences and also in the larger sequences of million year scale is interpreted in terms of sequence stratigraphy superposition of high frequency cyclicity on a longer term sea level trend led to multiplication of diagnostic surfaces se quence boundary and maximum flooding zones in the large scale sequences can thus be defined these zones are correlated between closely spaced sections but also from the swiss jura to normandy and to spain the narrow time lines given by milankovitch cyclicity then allow comparison of facies evolution in the di erent regions on a scale of 100 ka or less by filtering out local e ects of di erential subsidence and sediment supply a long term sea level curve valid for the northwestern margin of the tethys ocean can be reconstructed for the middle to late oxfordian di erential subsidence is implied from varying thicknesses of the sequences as well as from the distribution of siliciclastics which have been channelized through depressions tilted blocks reduced sedimentation or increased input of siliciclas tics appearing at the same time in all study areas point to a widespread regional tectonic event distribution through the sequences of climate dependent facies components such as corals ooids palynomorphs and siliciclastics indicates that climate changes were depen dent on atmospheric circulation patterns and thus on paleolatitude rainy periods and related increase of siliciclastics in the swiss jura were more abundant during low sea level stands whereas in the soria region they coincided with sea level highs through the com bination of high resolution sequence stratigraphy and cyclostratigraphy and supported by biostratigraphy and absolute dating it becomes possible to analyze paleoenvironmental changes in a very narrow time framework

layering and structural inheritance controls on fault zone structure in three dimensions a case study from the northern molasse basin switzerland mechanical heterogeneity of a sedimentary sequence exerts a primary control on the geometry of fault zones and the proportion of offset accommodated by folding the wildensbuch fault zone in the swiss molasse basin with a maximum throw of 40 m intersects a mesozoic section containing a thick 120 m clay dominated unit opalinus clay over and underlain by more competent limestone units interpretation of a 3d seismic reflection survey indicates that the fault zone formed by upward propagation of an east west trending basement structure through the mesozoic section in response to ne sw miocene extension this configuration formed an array of left stepping normal fault segments above and below the opalinus clay in cross section a broad monoclinal fold is observed in the opalinus clay folding however is not ubiquitous and occurs in the opalinus clay where fault segments above and below are oblique to one another where they are parallel the fault passes through the opalinus clay with little folding these observations demonstrate that even in strongly heterogeneous sequences here a four fold difference in both young9s modulus and cohesion between layers the occurrence of folding may depend on the local relationship between fault geometry and applied stress field rather than rheological properties alone

ionospheric remote sensing of the denali earthquake rayleigh surface waves 1 using the global positioning system we have detected ionospheric disturbances associated with the long period rayleigh waves from the 2002 denali earthquake ms 7 9 the dense california gps networks allowed us to map the ionospheric perturbations and to compute the group velocity with a high spatial resolution above the pacific coasts due to a low sampling rate a large error in the velocity determination remains nonetheless it demonstrates that bi static remote sensing measurements of seismic waves with gps networks can be performed monostatic measurements with a dedicated satellite could possibly be used to record in the ionosphere surface waves originating from large earthquakes such a space based remote sensing of the local group velocity of rayleigh surface waves would effectively complement the seismic networks for high resolution global tomography of the earth s lithosphere

complex hydrothermal alteration and illite k ar ages in upper visean molasse sediments and magmatic rocks of the variscan badenweiler lenzkirch suture zone black forest germany post collisional upper visean molasse sediments and magmatic rocks of the badenweiler lenzkirch zone reveal by microscopy of thin sections different degrees of hydrothermal illitization of feldspar and mica particles and xrd ir and xrf data of the 2 m fractions show illitic material as the dominant clay mineral consisting of a mixture of 1m and 2m1 polytypes moreover small amounts of illite smectite mixed layer minerals of r1 ordering are proved in the granites in the separates two illite mixing lines with different fe mg contents are verified between authigenic illite from feldspar alteration and detrital illite in the molasse sediments as well as between authigenic illite from feldspar alteration and altered mica flakes in the granites fe rich detrital chlorite is present within the molasse sediments while mixtures of high aluminous fe poor dioctahedral di trioctahedral chlorite with randomly interstratified chlorite smectite mixed layer minerals are formed from feldspar alteration in the granites illite k ar dating of the 2 and 0 63 m fractions yields hydrothermal illitization of feldspar and partial resetting of the k ar system of detrital illite and mica flakes in the molasse sediments at 200 c during upper permian to middle triassic times while the granites in the eastern part of the study area were not altered contemporaneously in contrast hydrothermal activity at 200 c during upper jurassic to lower cretaceous times occurred in the granites whereas these temperatures were too low for resetting the older permo triassic illite k ar ages in the molasse rocks within both k ar age clusters the data are seen to decrease with grain size and portion of illite 2m1 polytype the alteration phenomena indicate multiple hydrothermal episodes in the study area and they match those from the central and western european crust as fluid supply was controlled geodynamically by episodic break up of pangea

large scale convection patterns observed by dmsp the authors present a comprehensive compilation of the average distribution of the electrostatic potential across the high latitude ionosphere the averages are compiled from potentials along the satellite path calculated from thermal ion drift data from instrumentation on the defense meterological satellite program dmsp flights 8 and 9 satellites data were collected from the dmsp f8 satellite during the period september 1987 to december 1990 and from the dmsp f9 satellite during the period march 1988 to december 1990 the potential distributions are separated by geomagnetic position season and orientation of the interplanetary magnetic field imf and then averages of the distributions are calculated the average potential distributions clearly show the displacement of polar cap convection contours to the dusk or dawk flanks under the influence of the imf b sub y component the cross cap potential decreases as imf b sub z changes from southward to northward the average distributions indicate that the development of more than two convection cells for northward imf is either uncommon or nonexistent for imf b sub z 0 and b sub z vert bar b sub y vert bar a distorted pattern is observed in the average potential distribution not a four cell pattern as some previous studies suggest it should be for allmore orientations of the imf the convection reversal boundary at the poleward edge of the auroral zone is observed in the average distributions to be a rotational boundary it is not a shear boundary as suggested by some previous investigations on average the harang discontinuity convection reversal in the auroral zone near midnight is observed to exist weakly or not at all when examining individual passes a strong eastward flow is present sometimes in the region of the harang discontinuity especially on the poleward boundary but not at all times as implied by the heppner maynard model 39 refs 9 figs 2 tabs less

the 2009 samoa and 2010 chile tsunamis as observed in the ionosphere using gps total electron content 1 ground based global positioning system gps measurements of ionospheric total electron content tec show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following two recent seismic events the samoa earthquake of 29 september 2009 and the chile earthquake of 27 february 2010 both earthquakes produced ocean tsunamis that were destructive to coastal communities near the epicenters and both were observed in tidal gauge and buoy measurements throughout the pacific ocean we observe fluctuations in tec correlated in time space and wave properties with these tsunamis using the jet propulsion laboratory s global ionospheric mapping software these tec measurements were band pass filtered to remove ionospheric tec variations with wavelengths and periods outside the typical range for tsunamis observable variations in tec appear correlated with the tsunamis in some locations hawaii and japan but not in others southern california or near the epicenters where variations are observed the typical amplitude tends to be 0 1 0 2 tec units for these events on the order of 1 of the background tec value these observations are compared to estimates of expected tsunami driven tec variations produced by embry riddle aeronautical university s spectral full wave model an atmosphere ionosphere coupled model and are found to be in good agreement significant tec variations are not always seen when a tsunami is present but in these two events the regions where a strong ocean tsunami was observed coincided with clear tec observations while a lack of clear tec observations coincided with smaller sea surface height amplitudes there exists the potential to apply these detection techniques to real time gps tec data providing estimates of tsunami speed and amplitude that may be useful for early warning systems

a numerical study of three dimensional gravity waves triggered by deep tropical convection and their role in the dynamics of the qbo abstract a 3d mesoscale model is used to study the structure of convectively triggered gravity waves in the tropics and their role in the dynamics of the middle atmosphere simulations with three stratospheric background zonal wind cases are examined in the first case the background wind profile is constant the other two are representative of the easterly and westerly phases of the quasi biennial oscillation qbo spectral analysis is used to link the structure of the triggered gravity waves to the dominant vertical wavelength of the latent heating within the convection in the qbo wind shear cases upward propagating gravity waves are damped as they approach their critical layer the signature of critical layer absorption is clearly visible in the profiles of vertical momentum flux divergence in the simulations with open boundary conditions the response to vertical momentum flux divergence takes the form of large dynamic pressure differences between the east and west boundaries together with acceler

arecibo observations of ionospheric perturbations associated with the passage of tropical storm odette 1 a suite of instruments including incoherent scatter radar ionosonde and a satellite bourne gps receiver observed the ionosphere immediately following the passage of a tropical storm tropical storm odette formed on 4 december 2003 and proceeded northeasterly over the next 4 days passing within 600 km of the arecibo observatory ao on the night of 7 8 december ao measured f region plasma densities and velocities nearly coincident with the storm large velocity variations 10 80 m s are evident in the plasma drift components the variations appear wave like with an average period of 90 min at 367 km zonal drifts were observed with magnitudes significantly greater than commonly observed for similar geomagnetic conditions the ramey ionosonde observed intense midlatitude spread f on the night following the closest passage of the storm gps occultations within the storm path showed an increase in gravity wave activity and f region scintillation combining the local increase in gravity wave activity with the large drift variations and dominant meridional electric field observed immediately following the storm s traversal of the flux tube coincident with the ao observing volume provide insight into coupling between mesoscale weather systems and the ionosphere

active normal faulting beneath a salt layer an experimental study of deformation patterns in the cover sequence scaled experimental models show that the presence of a viscous layer such as salt facilitates the development of extensional forced folds above active normal faults the geometries of the extensional forced folds and their associated secondary fault patterns depend on the thickness and viscosity of the viscous layer the thickness of the cover sequence the strength and ductility of the cover sequence and the magnitude and rate of displacement on the underlying master normal fault increasing the thickness of the viscous layer and the cohesive strength and ductility of the overburden enhances the decoupling between the deep and shallow deformation alternatively increasing the viscosity of the viscous layer the thickness of the overburden and the magnitude and rate of displacement on the master normal fault reduces the decoupling between the deep and shallow deformation enhanced decoupling facilitates the formation of broad extensional forced folds and the development of detached secondary faults both near and far from the master normal faults the model predicted deformation patterns closely resemble those observed in the gulf of suez the haltenbanken area of offshore norway and the jeanne d arc basin of the grand banks offshore southeastern canada

sea level changes an integrated approach sea level changes an integrated approach in october 1985 sepm sponsored a four day conference entitled sea level changes an integrated approach the purpose of the conference was to provide a forum for an interdisciplinary exchange of ideas on sea level changes and to provide an opportunity for integrating various types of evidence in approaching unresolved issues the conference was successful in bringing together scientists from industry academia and government representing all of the major geosciences disciplines presentations of many new papers plus significant releases of data that were previously held proprietary provided fertile ground for discussion this much cited volume represents the best of the material presented at the conference includes the early vail chart

ionospheric gps total electron content tec disturbances triggered by the 26 december 2004 indian ocean tsunami 1 tsunami ionospheric disturbances tids of the 26 december 2004 mw 9 3 sumatra earthquake are detected by the total electron content tec of ground based receivers of the global positioning system gps in the indian ocean area it is found that the tsunami waves triggered atmospheric disturbances near the sea surface which then traveled upward with an average velocity of about 730 m s 2700 km hr into the ionosphere and significantly disturbed the electron density within it results further show that the tids which have maximum height of about 8 6 17 2 km periods of 10 20 min and horizontal wavelengths of 120 240 km travel away from the epicenter with an average horizontal speed of about 700 km hr 190 m s in the ionosphere

late oxfordian to late kimmeridgian carbonate deposits of nw switzerland swiss jura stratigraphical and palaeogeographical implications in the transition area between the paris basin and the tethys abstract geological sections of the shallow water carbonate dominated sedimentary system of the late jurassic reuchenette formation in northwestern switzerland have been studied between the southern jura mountains and the tabular jura the largest sections show a characteristic cyclic stacking pattern up to now the age of these sediments including the type section linking the boreal and tethyan realms was biostratigraphically poorly constrained in the tabular jura five 3rd order sequences can be assigned to the planula to eudoxus zone late oxfordian to late kimmeridgian using index fossils ammonites and ostracodes jank m 2004 new insights into the development of the late jurassic reuchenette formation of nw switzerland late oxfordian to late kimmeridgian jura mountains dissertationen aus dem geologisch palaontologischen institut der universitat basel 32 121 pp this time control and several new outcrops in combination with mineralostratigraphical and lithological marker beds allow the correlation and dating of the thickest sections of the reuchenette formation and thus serve to improve the previously estimated ages of their sequence boundaries the variability of stacking pattern and facies between sections also reveals distinctive changes in facies evolution related to late palaeozoic basement structures and synsedimentary subsidence these structures acted as important controlling factors for the sediment distribution of the reuchenette formation besides the sea level fluctuations the interplay of sea level changes and synsedimentary subsidence is outlined by lateral thickness variations and shifting depositional environments a close examination of these changes also sheds much light on the nature of platform topography in the transition area between the paris basin in the north and the tethys in the south or more generally between the boreal and tethyan realms during the planula to divisum time intervals the study area was a flat platform with a more or less uniform facies distribution which connected the above mentioned realms during the divisum to acanthicum time intervals this platform changed into a pronounced basin and swell morpoholgy with specific depositional environments and separated the paris basin from the tethys

molecular and isotopic characterization of biomarkers in the frick swiss jura sediments a palaeoenvironmental reconstruction on the northern tethys margin abstract molecular and stable carbon isotope compositions of source specific hydrocarbons have been used to reconstruct palaeoenvironmental conditions during deposition of the middle hettangian to upper sinemurian sediments on the northern epicontinental tethys margin frick swiss jura increasing algal cyanobacterial and phytoplanktonic i e dinoflagellate contributions associated with the 13 c enrichment of cyanobacteria derivatives i e hopanes and monomethylalkanes suggest enhanced primary productivity upsection this is related to the 13 c enrichment of dissolved co 2 in the upper layers and the progressive increase of depth and oxygenation of the water column in the middle hettangian shallow water environments lagoon the occurrence of green sulfur bacteria chlorobiaceae derivatives indicates that the lower part of the water column was strictly anoxic and rich in h 2 s since these bacteria require very low light intensity to grow these euxinic conditions may be extended up to the photic zone allowing for anaerobic photosynthesis light penetration depth is most likely reduced by high productivity and or turbidity in the photic zone in these sediments 13 c depleted hopanoids 39 5 are most likely associated with phototrophic purple sulfur bacteria utilizing isotopically light organic carbon at the base of the aerobic zone these purple sulfur bacteria may have consumed the h 2 s used by chlorobiaceae in the deeper layers and thus sustained the algae and cyanobacteria productivity in the upper layers the 13 c depleted carbonate 13 3 may be partially related to the anaerobic oxidation of the organic matter during bacterial sulfate reduction

a semi empirical model of the contribution from sporadic meteoroid sources on the meteor input function in the mlt observed at arecibo 1 in this paper we present a modeling and observational study of the micrometeor input function with a focus on understanding how each of the extraterrestrial sporadic meteoroid sources contributes to the observed meteoric flux in the mesosphere and lower thermosphere mlt atmospheric region for this purpose we expand the model presented by janches et al 2006 using a monte carlo technique and incorporating 1 a widely accepted global mass flux which is divided into different proportions among the known sporadic meteoroid sources as the initial input above earth s atmosphere 2 contemporary knowledge on the source s velocity and radiant distributions and 3 the full integration of the canonical meteor equations that describe the meteoroid entry and ablation physics in addition we constrain the initial input through a comparison of our modeled results with meteor observations obtained with the 430 mhz high power and large aperture hpla arecibo radar in puerto rico that covers all seasons the predicted meteor rates and velocity distributions are in excellent agreement with the observed ones without the need for any additional normalization factor our results indicate that although the earth s apex centered radiant source which is characterized by high geocentric speeds 55 km s appears to be 33 of the meteoroids in the solar system at 1 au it accounts for 60 of the meteors observed by the arecibo hpla radar in the atmosphere the remaining 40 of observed meteors originate mostly from the helion and anti helion sources with a very small but constant during the day contribution of the south and north toroidal sources these results also suggest that particles smaller than 10 3 g with slow velocities 30 km s will not significantly ablate and never become observable meteors the motivation of this effort is to construct a new and more precise mif model needed for the subsequent modeling of the atmospheric phenomena related to the meteoric flux

generation of kilometer scale irregularities during the midnight collapse at arecibo coordinated observations of the incoherent scatter radar at arecibo puerto rico and total electron content scintillation measurements made by using the 137 mhz transmissions from the geostationary satellite sms 1 from the nearby station of ramey are studied to determine the background ionospheric conditions necessary for the generation of kilometer scale irregularities in the midlatitude ionosphere it is found that the well known midnight descent or collapse of the f region known to occur in this part of the world is sometimes associated with increases in the bottomside electron content as well as large scintillation events 10 db from a measurement of vector ion velocities and electron densities during such events it is determined that the scintillations occur in a region of eastward and northward electric fields coupled with a northward directed density gradient caused by the northward propagation of the midnight collapse the role of possible plasma instability mechanisms specifically the e b gradient drift instability and the perkins instability is discussed in the formation of the kilometer scale irregularities giving rise to vhf scintillations

the alpine nappe stack in western austria a crustal scale cross section based on an n s oriented crustal scale cross section running east of the rhine valley in vorarlberg western austria we address the alpine nappe stack and discuss the boundary between central and eastern alps for our cross section we used surface geology drillings and reinterpreted seismic lines together with published sections the general architecture of the examined area can be described as a typical foreland fold and thrust belt comprising the tectonic units of the subalpine molasse ultra helvetic penninic and austroalpine nappes these units overthrusted the autochthonous molasse along the south dipping listric alpine basal thrust the european basement together with its autochthonous cover dips gently towards the south and is dissected by normal faults and trough structures the seismic data clearly show an offset not only of the top of the european basement but also of the mesozoic cover and the lower marine molasse this indicates an activity of the structures as normal faults after the sedimentation of the lower marine molasse the subalpine molasse is multiply stacked forming a triangle zone at the boundary with the foreland molasse the shortening within the subalpine molasse amounts to approximately 45 km 67 as deduced from our cross section with the lower marine molasse as a reference the hinterland dipping duplex structure of the helvetic nappes is deduced from surface and borehole data there are at least two helvetic nappes needed to fill the available space between the molasse below and the northpenninic above this is in line with the westerly located nrp20 east transect schmid et al tectonics 15 5 1047 1048 1996 schmid et al the transmed atlas the mediterranean region from crust to mantle 2004 where the two helvetic nappes are separated by the santis thrust yet in contrast to the helvetic nappes in the nrp20 east transect both of our helvetic nappes comprise cretaceous and jurassic strata this change is explained by an eastward down stepping of the santis thrust along a pre existing approximately n s striking lateral ramp bounding an inverted jurassic graben structure below the rhine valley this causes the santis thrust to detach the base cretaceous west of the rhine valley and the base jurassic units east of it this graben controlled change in detachment level leads to the formation of quite different nappe stacks on either side of the rhine valley and a fault controlled appearance of the boundary between the central and eastern alps

gps observation of continent size traveling tec pulsations at the start of geomagnetic storms we report our experimental observation of continent size traveling plasma disturbances using gps measurements of total electron content tec over the north american sector these plasma disturbances occurred at the beginning of geomagnetic storms immediately after the shock arrived and prior to the appearance of large scale traveling ionospheric disturbances lstids from the auroral region specifically these supersize tec perturbations were observed when the interplanetary magnetic field bz was oscillating between northward and southward directions they were found to propagate zonally with a propagation speed of 2 3 km s we interpret these tec pulsations as ion drift waves in the magnetosphere plasmasphere that propagate azimuthally inside the gps orbit

the ardeche palaeomargin of the south east basin of france mesozoic evolution of a part of the tethyan continental margin geologie profonde de la france programme abstract this paper incorporates the results of seismic and gravity investigations borehole data and studies of sedimentology biostratigraphy sequence stratigraphy and structural geology carried out in the framework of the deep geology of france programme the main purpose of the paper is to define the structure and to reconstruct the evolution of the ardeche palaeomargin of the south east basin of france from the stephanian to the end of the mesozoic the acquisition and processing of three seismic reflection profiles the drilling of two scientific boreholes ba1 and mm1 and subsequent structural modelling with the use of cross section balancing techniques applied to both the depth migrated seismic and geological sections provide new geometrical constraints which lead to the following hypothesis of the geodynamic evolution of the margin 1 1 late palaeozoic extension with the development of high angle basement faults asymmetrical permian half grabens pre extension sedimentary cover 2 2 during the middle triassic a pre rift stage with the creation of small fault blocks and in the late triassic the formation of an e w flexure 3 3 end lias early jurassic to middle jurassic formation of a major detachment in the carboniferous coal measures leading to complete decoupling of the mesozoic sedimentary cover from the basement this episode of extension coeval with the opening of tethys can be related to a phase of episodic rifting between the late sinemurian and the late bathonian i e during 30 ma 4 4 late jurassic to early cretaceous thermal subsidence with regional downwarping of the basement towards the east 5 5 after the late cretaceous the period of maximum burial pyrenean and alpine deformation in the south and east causing progressive uplift of the ardeche palaeomargin as much as two kilometres of mesozoic deposits subsequently being eroded from the section during the tertiary

tectonothermal history of the schwarzwald ore district germany an apatite triple dating approach abstract exceptionally large u rich apatite from the schwarzwald ore district germany was triple dated using id tims u pb fission track ft and u th he dating methods the aim of adopting the multi dating approach on a single sample was to i further constrain thermo tectonic evolution of the schwarzwald from the formation of crystalline basement through to cooling and exhumation and ii test potential and limitations of in situ ft u th he double dating the apatite u pb age of 289 5 4 5 ma records the cooling of the basement through the 550 c during the early permian and brackets the age of the apatite hosting rhyolite between 289 5 4 5 ma and 314 6 ma which is the age of rhyolite hosting granite this is in excellent agreement with radiometric ages of related rhyolites and fits with the magmatic evolution of the schwarzwald during variscan orogeny in the eocene between 50 and 40 ma the basement resided at 100 c and then cooled to surface temperatures as revealed by the ft age 37 6 1 3 ma and thermal modelling results based on track lengths during the cooling event the basement was likely exhumed as a rift shoulder of newly formed upper rhine graben rift nine apatite grains yielded u th he ages from 30 7 1 5 to 65 0 2 6 ma mean age 45 7 1 3 ma three possible reasons for the lack of reproducibility are i non homogeneous distribution of parent isotopes evidenced by strong u zoning ii bad neighbourhood causing implantation of extraneous he and iii radiation damage leading to increased he retentivity implied by the high 250 ppm u concentration these problems could not be circumvented by mechanical abrasion of outermost rim of dated crystals which yielded u th he ages from 26 0 1 0 to 56 2 2 2 ma mean age 37 2 1 4 ma in situ ft and traditional u th he double dating of single apatite crystals revealed that the vast majority of u th he ages were younger than indistinguishable from or overlap within error with corresponding ft ages proving the robustness of this approach the results also show that apparent discrepancies between ft and u th he ages reported in the literature may arise simply as a result of statistical misconceptions and conventional data treatment considering the range of single grain ft ages and the oldest single grain ft age in addition to the central ft age may provide an effective basis on which to evaluate the viability of u th he data

botryoidal hematite from the schwarzwald germany heterogeneous uranium distributions and their bearing on the helium dating method abstract neutron induced fission tracks of small grain mounts of two co genetic botryoidal hematites eisenbach hematite manganese mineralization district mittelschwarzwald germany reveal substantial heterogeneous 235 u distributions 235 u fission tracks in the three shells of one hematite yield total uranium concentrations of 26 48 and 160 ppm 2 errors of approximately20 respectively the other hematite consists of a coherent mineralogical unit devoid of shell type features in which four localities have been probed with a range in total uranium between 26 and 600 ppm induced fission tracks from a larger section of the single unit hematite show a subparallel arrangement of five well defined 235 u zones with densities ranging from about 10 6 tracks cm 2 in zone 5 to approximately 25 10 6 tracks cm 2 in zone 2 additionally in zones 3 5 gradual internal track density variations of over 100 can be recognized a traverse shows that there is an overall decrease in radioactivity from zone 1 to zone 5 an autoradiograph confirms the existence of five zones with different activities and allows correlation of the high activity zone 2 with a 0 5 mm thin internal hematite micro layer analyses by mass spectrometer of the triple shell hematite resulted in the following concentrations 26 45 and 166 ppm uranium 2 errors of1 and 0 55 3 25 l g 4 he 2 errors of3 the four probed localities in the single unit hematite show smaller variations at 40 73 ppm uranium 2 errors of0 5 and 0 75 1 37 l g 4 he 2 errors of3 spectrometry of thorium yields values in the 1 5 ppm range for both hematites the uranium and 4 he concentration differences measured allow construction of two internal u th he isochrons yielding identical ages 2 error of 156 1 ma and 155 6 ma concordance of both isochrons in our opinion is strong evidence for a geologically significant age we interpret the data as emplacement ages further we suggest that botryoidal hematite has the potential to be a prolific chronometer for the helium method on mesozoic hematite bearing mineralizations

k ar dating of episodic mesozoic fluid migrations along the fault system of gernsbach between the moldanubian and saxothuringian northern black forest germany along the sw ne trending fault zone of gernsbach northern black forest over a distance of about 45 km between baden baden and pforzheim basal series of the sedimentary cover are extensively altered by hydrothermal solutions the fluids were conveyed in the fault zone and because of favourable permeabilities they spread out along the unconformity between the basement and sedimentary cover k ar dates on authigenic white micas illites and hydrothermally altered detrital micas point to the occurrence of two major episodes of fluid migration the extensive alteration along the entire fault system occurred about 150 ma ago during the jurassic in relation to these hydrothermal activities the epigenetic strata bound uranium deposit of mullenbach originated in upper carboniferous sediments near the fault and the fluorite quartz vein type mineralization of kafersteige was formed along the fault about 100 ma ago during the cretaceous the results indicate various geological processes of the fault system of gernsbach which is located between the saxothuringian and moldanubian zone the mobilization of the fluids and the formation of the ore deposits were probably caused by and connected with tectonic activities in mid europe

deciphering the sedimentological expression of tectonics eustasy and climate a basinwide study of the corallian formation southern england abstract jurassic corallian formation outcrops along the dorset coast composed of carbonate and siliciclastic shallow marine facies are classic sites for british geologists they have been regarded as typical of cyclically deposited strata characterized by repeated sandstone mudstone and carbonate lithologies the stratigraphy has been interpreted as evidence for rapid eustatic sea level change throughout the oxfordian this study s basinwide database however shows that study of the outcrops alone has led to oversimplified conclusions the stratigraphy records the migration of siliciclastic source areas through time pulses of terrigenous sand reflect local uplift and increased weathering rather than rapid eustatic sea level falls the recognition of mixed siliciclastic carbonate beds makes an argument for rapid changes in water depth less convincing and reveals that lateral migration of shallow water facies is a more plausible explanation for the observed stratigraphy coeval carbonate and siliciclastic deposition around the basin shows that neither eustasy nor climatic change can be solely responsible for the stratigraphy the strata reflect instead a complex interplay of episodic local tectonism siliciclastic source area migration and marine circulation patterns

the significance of hiatus beds in shallow water mudstones an example from the middle jurassic of switzerland abstract limestone beds formed in nearly carbonate free shallow water mudstones by discontinuous sedimentation and erosion are called hiatus beds anaerobic oxidation of organic matter by microbes provided excess alkalinity inducing carbonate precipitation a multiphase history of such beds is documented from the swiss jurassic by several cementation and dissolution phases four cement types occur micrite as earliest cement 13c 10 to 20o oo stellate calcite between micrite cemented parts 13c 5 to 10o oo fibrous calcite cement in dissolution cavities 13c 30o oo and blocky calcite in remaining pores 13c 5o oo except for the late blocky cement all cements contain pyrite indicating carbonate precipitation within the sulfate reduction zone after early cementation by micrite the beds moved relatively upwards into a shallower geochemical zone and some even to the seafloor because of erosion cavities formed during reburial by dissolution in the upper part of the sulfate reduction zone and in the upper part of the methanogenic zone strongly reduced sedimentation rates provided the requisite stable geochemical conditions for at least several thousands of years which permitted precipitation and dissolution of carbonate by biochemical processes and diffusion this happened on short lived swells caused by differential subsidence and rotation along listric faults when basement structures became reactivated during the extensional stress regime from opening of the tethys during the jurassic and cretaceous breakup of pangea the shelf area increased and differential subsidence on these newly formed shelves was the main factor responsible for the observed post paleozoic maximum in hiatus beds and hiatus concretions

testing the preservation potential of early diagenetic dolomites as geochemical archives early marine diagenetic dolomite is a rather thermodynamically stable carbonate phase and has potential to act as an archive of marine porewater properties however the variety of early to late diagenetic dolomite phases that can coexist within a single sample can result in extensive complexity here the archive potential of early marine dolomites exposed to extreme post depositional processes is tested using various types of analyses including petrography fluid inclusion data stable 13c and 18o isotopes 87sr 86sr ratios and u pb age dating of various dolomite phases in this example a triassic carbonate platform was dissected and overprinted diagenetic temperatures of 50 to 430 c in a strike slip zone in southern spain eight episodes of dolomitization a dolostone cataclasite and late stage meteoric vadose cementation were recognized the following processes were found to be diagenetically relevant i protolith deposition and fabric preservation and marine dolomitization of precursor aragonite and calcite during the middle late triassic ii intermediate burial and formation of zebra saddle dolomite and precipitation of various dolomite cements in a proto atlantic opening stress regime t ca 250 c during the early middle jurassic iii dolomite cement precipitation during early alpine tectonism rapid burial to ca 15 km and high grade anchizone overprint during alpine tectonic evolution in the early eocene to early miocene iv brecciation of dolostones to cataclasite during the onset of the carboneras fault zone activity during the middle miocene and v late stage regression and subsequent meteoric overprint data shown here document that under favourable conditions early diagenetic marine dolomites and their archive data may resist petrographic and geochemical resetting over time intervals of 108 or more years evidence for this preservation includes preserved late triassic seawater 13cdic values and primary fluid inclusion data data also indicate that oversimplified statements based on bulk data from other petrographically complex dolomite archives must be considered with caution

from rifting to drifting tectonic evolution of the south alpine upper crust from the triassic to the early cretaceous abstract the tectonic evolution of the south alpine rifted margin is discussed on the base of four palinspastic upper crustal profiles extension related to the movements between adria and europe began in the norian after variscan orogeny late carboniferous to middle permian orogenic collapse and continental scale wrenching from the late triassic to the early liassic stretching was mostly limited to the lombardian basin during this time extension was mainly controlled by four major listric faults symmetrically centred around the late carboniferous early permian collio grabens smaller faults which also started in the norian were progressively de activated during the late triassic after the middle liassic faulting in the lombardian basin gradually ceased and the site of extension shifted westwards i e towards the future site of crustal separation extension was then controlled by a set of west dipping normal faults oceanic crust was formed not later than 157 ma the overall extension along the profile which had a final length of 290 km was 52 km which corresponds to a stretching factor of 1 22 for the whole length of the preserved margin the strain rate is ca 1 10 16 s the sedimentation history suggests that the extension of the south alpine margin was a continuous process from the norian to the middle jurassic the changes in tectonic pattern are related to progressive hardening of the lithospheric segment undergoing slow extension

collapse of a hercynian tibetan plateau into a late palaeozoic european basin and range province the large width the importance of crustal shortening and the likelihood of thick crust in the late palaeozoic hercynian or variscan belt of southern europe suggest a tectonic evolution analogous to the evolution of the tibetan plateau and its neighbouring himalaya1 and of the altiplano and other high plateaux of the andes here we extend dewey and burke s analogy1 of the hercynian chain with tibet to include the subsequent stage of pervasive normal faulting and crustal extension and thinning which characterize the active tectonics of tibet parts of the high andes and the basin and range province of western north america it appears that normal faulting and rifting also characterize the late palaeozoic tectonic activity of the hercynian chain

discriminating between tectonic and eustatic controls on the stratigraphic record in the paris basin the quantification of tectonic and eustatic factors in the control of the sedimentary record is one of the main questions in sedimentary basin dynamics we propose two methods allowing i 3d measurement of accommodation at basin scale and ii to decipher between local 10 100 km wavelength and basin scale accommodation the local signal is necessarily of tectonic origin the basin scale signal is of both eustatic and large tectonic origin the measurement of accommodation requires a high resolution time lines calibrated in ages sequence stratigraphy on well logs and biostratigraphy on cores b decompacted lithologies well logs and c palaeodepth palaeoaltitude sedimentology and well logs application of these methods to the intracratonic paris basin during the lias early jurassic suggests a tectonic origin for the 1 5 myr stratigraphic cycles with basin scale flexure during transgressive half cycles and 10 100 km uplift of basement units during regressive half cycles

msx satellite observations of thunderstorm generated gravity waves in mid wave infrared images of the upper stratosphere data from the midcourse space experiment msx has provided the first observations of thunderstorm generated gravity waves imaged from space gravity wave theory predicts that isolated sufficiently convective thunderstorms can launch waves and create a unique intensity pattern of concentric circles on a radiating surface of constant altitude above such a storm among the msx constant nadir angle mid wave infrared mwir observations two instances of such patterns have been identified it was confirmed from meteorological satellite images that highly convective isolated thunderstorms occurred at the locations and times expected

sequential and climatic framework of the growth and demise of a carbonate platform implications for the peritidal cycles late jurassic north eastern france the middle oxfordian of the eastern paris basin constitutes a remarkable example of the growth and demise of a carbonate platform fischer plots sedimentary and diagenetic features allow the identification of four depositional cycles s5 to s8 in the transversarium zone they are inserted in a lower frequency cycle of increased decreased accommodation space soiii the long term period of accommodation creation occurred during the older s5 and s6 cycles the maximum accommodation zone being located in the lower part of the s6 cycle this high accommodation period was tectonically controlled and was coeval with local distensive activity of a hercynian fault a major minimum accommodation zone exists during the s8 cycle at that time the platform was isolated and presented both a windward and a leeward margin the growth of the platform was favoured by a warm and arid climate oligotrophic conditions and reduced siliciclastic input during a highstand in relative sea level these palaeoenvironmental features favoured the proliferation of phototrophic organisms producing carbonate material the death of the platform was generated by a reduction in the carbonate production surface during a lowstand in relative sea level and by the appearance of mesotrophic conditions induced by the increase in siliciclastic inputs at the beginning of a period with a cooler and more humid climate in the eastern paris basin during the middle oxfordian the parasequences are ordered and present greenhouse characteristics in contrast at the beginning of the s8 cycle the randomness in the thickness of contiguous parasequences increased decreased carbonate production during the lowstand caused by a transition from photozoan to heterozoan benthic communities certainly favoured this randomness and the appearance of catch down parasequences

nostradamus the radar that wanted to be a seismometer 1 surface waves emitted after large earthquakes are known to induce by dynamic coupling atmospheric infrasonic waves propagating upward through the neutral and ionized atmosphere those waves have been detected in the past at ionospheric heights using a variety of techniques such as hf doppler sounding or gps receivers the hf doppler technique particularly sensitive to the ionospheric signature of rayleigh waves is used here to show ionospheric perturbations consistent with the propagation of rayleigh wave phases r1 and r2 following the sumatra earthquake on the 28 march 2005 m 8 6 this is in our knowledge the first time that the phase r2 is detected by ionospheric sounding in addition we prove here that the ionospheric signature of r2 is also observed by over the horizon oth radar the latter was never used before to detect seismic signature in the ionosphere adding the oth radar to the list of the ionospheric seismometers we discuss and compare the performances of the three different instruments mentioned above namely hf doppler sounding gps receivers and oth radar

plio pleistocene transpressional reactivation of paleozoic and paleogene structures in the rhine bresse transform zone northern switzerland and eastern france pliocene to recent uplift and shortening in the southern rhinegraben is documented by deformation of pliocene fluvial gravels deposited on a nearly planar surface as well as by progressive deflection and capture of rivers this deformation is suggested to result from thick skinned tectonic movements as evidenced by ob servations on seismic records which demonstrate a spatial coincidence between en chelon anticlines at the surface and faults located in the crystalline basement these findings contradict the often invoked thin skinned tectonism in the recent tectonic history of the rhine graben in particular the transfer zone between the rhinegraben and the bressegraben is very suitable for reactivation under the present day stress field thick skinned reactivation of faults in the basement is also expressed by focal plane mechanisms of recent earth quakes showing strike slip rather than reverse faulting characteristics this is of importance for the densely populated and industrialised southern rhinegraben pre viously affected by large earthquakes in historical times e g basel 1356

geochronological constraints on the trans hudsonian tectono metamorphic evolution of the pre athabasca basement within the wollaston mudjatik transition zone saskatchewan the hudsonian pressure temperature deformation time p t d t evolution of the pre athabasca crystalline basement 1700 ma of the wollaston mudjatik transition zone wmtz highlights two major tectono metamorphic events m1 d1 and m2 d2 the ages of these two event have been obtained by in situ la icpms u th pb dating of monazite from grt crd bearing pelitic gneiss and u pb analyses performed on zircons from pegmatites using both exposed basement and drill cores from the wolly mcclean exploration drilling project the m1 d1 event interpreted as the burial of the thinned hearne margin via southward thrusting to pressures varying from 10 to 6 kbar occurred between ca 1840 and 1813 ma the m2 d2 event producing the northeast structural trend of the wmtz was formed in a sinistral transpressional tectonic regime during the late stage of the hudsonian oblique collision between ca 1813 and 1770 ma thermobarometric estimates on the m2 d2 assemblages show that the entire studied area was reequilibrated at about 5 kbar and 750 825 c trans hudsonian pegmatites are viewed as the main proto ore of the uranium rich athabasca unconformity type deposits formation transfer and differenciation of these trans hudsonian pegmatites are replaced in this p t d t evolution during the 1840 1813 ma m1 d1 partial melting event the first batches of melt produced in the deep crust are the most likely enriched in uranium then these melts were transferred upwards to the upper crustal levels owing to the development of crustal scale steeply dipping d2 shear zones and finally were differentiated to form uranium enriched pegmatites between 1813 and 1770 ma some monazite and zircon grains within retrogressed migmatites recorded a later event at ca 1720 ma interpreted as the terminal cooling event down to 300 400 c responsible for partial retrogression of metamorphic assemblages this age provides new insights into the timing of the onset of the athabasca sedimentation that should therefore be at least 1710 ma old or younger

graben width controlling syn rift sedimentation the palaeogene southern upper rhine graben as an example eocene to early oligocene syn rift deposits of the southern upper rhine graben urg accumulated in restricted environments sedimentation was controlled by local clastic supply from the graben flanks as well as by strong intra basinal variations in accommodation space due to differential tectonic subsidence that in turn led to pronounced lateral variations in depositional environment three large scale cycles of intensified evaporite sedimentation were interrupted by temporary changes towards brackish or freshwater conditions they form three major base level cycles that can be traced throughout the basin each of them representing a stratigraphic sub unit a relatively constant amount of horizontal extension l in the range of 4 5 km has been estimated for the urg from numerous cross sections the width of the rift lf however varies between 35 and more than 60 km resulting in a variable crustal stretching factor between the bounding masterfaults apart from block tilting tectonic subsidence was therefore largely controlled by changes in the initial rift width l0 the along strike variations of the graben width are responsible for the development of a deep trough like evaporite basin potash basin in the narrowest part of the southern urg adjacent to shallow areas in the wider parts of the rift such as the colmar swell in the north and the rhine bresse transfer zone that delimits the urg to the south under a constant amount of extension the along strike variation in rift width is the principal factor controlling depo centre development in extensional basins

evidence for orographic wave heating in the equatorial thermosphere at solar maximum fabry perot interferometer observations of equatorial 630 nm airglow thermospheric winds and temperatures were made at arequipa peru 16 5 s 71 5 w during the solar maximum years of 1989 and 1990 examination of the thermospheric winds measured from doppler shifts of the 630 nm airglow emission in the two directions east and west of arequipa shows that the zonal wind is often significantly weaker over the andes east than over the pacific west in winter between 19 lt and 24 lt the typical reductions in speed found were 40 to 70 m s in the same time period the temperature results show elevated values of 200 500 k for the three directions north east and zenith over mountainous terrain compared with those of the two directions west and south over water this effect fades near equinoctial periods examination of the standard deviation of the temperature ohservations for the five directions showed an increase in this value above the measurement error hy a factor of three for the direction toward the andes east but not for the direction over water south this elevation is consistent with wave activity as a source of the heating viscous dissipation of waves propagating into the thermosphere region from below is suggested as an explanation for the localized regions of heating

the irish variscides problems perspectives and some solutions a review is presented of interpretations made to date of the irish variscides and the various models of late palaeozoic crustal evolution an examination is then made of the factors controlling variscan strain in ireland including lithological competence basement fabric and basement cover thickness from this the difficulties of recognizing variscan fronts and fold belts are emphasized in order to determine whether all putative variscan strain is indeed variscan in age new time temperature data vitrinite reflectance apatite fission track populations are discussed along with offshore data a case is then presented for recognizing quite distinct episodes of both variscan and post variscan heating and deformation some of the implications for the variscides to the east are briefly examined and the suitability of a regional escape tectonics model is tested

the south western black forest and the upper rhine graben main border fault thermal history and hydrothermal fluid flow the thermal history of the south westernmost black forest germany and the adjacent upper rhine graben were constrained by a combination of apatite and zircon fission track ft and microstructural analyses after intrusion of palaeozoic granitic plutons in the black forest the thermal regime of the studied area re equilibrated during the late permian and the mesozoic interrupted by enhanced hydrothermal activity during the jurassic at the eastern flank of the upper rhine graben along the main border fault the analysed samples show microstructural characteristics related to repeated tectonic and hydrothermal activities the integration of microstructural observations of the cataclastic fault gouge with the ft data identifies the existence of repeated tectonic related fluid flow events characterised by different thermal conditions the older took place during the variscan and or mesozoic time at temperatures lower than 280 c whereas the younger was probably contemporary with the cenozoic rifting of the upper rhine graben at temperatures not higher than 150 c

gravity waves appearing in a high resolution gcm simulation global characteristics of gravity waves in the lower stratosphere are examined using a gcm with high resolution in both the horizontal t106 corresponding to about 120 km and the vertical 600 m the bottom boundary condition of the model is that of an aquaplanet with perpetual february sea surface temperature the simulated gravity waves are in good agreement with mesosphere stratosphere troposphere mst radar observations at a middle latitude on the gravity wave structure and on the frequency spectra as a function of height the frequency spectra of simulated wind and temperature fluctuations are also examined as a function of latitude large values of spectral density are observed at frequencies higher than the inertial frequency f in a weak wind region around 20 km which is consistent with the characteristics of internal gravity waves an isolated peak is observed near f for horizontal wind spectra at latitudes higher than 108 while the energy is distributed in a wide range of frequency at lower latitudes where f approaches zero further analysis is performed of those fluctuations having periods shorter than 24 h and those having vertical wavelengths smaller than 5 km these are frequently analyzed as gravity waves using observation data the distribution of energy and momentum fluxes in the latitude height section is examined the result indicates that short period waves mostly propagate upward and poleward from the equatorial region the wave energy reaches about 508 lat at the 27 km altitude a negative positive maximum of vertical flux of meridional momentum y9w9 is seen above the subtropical jet in the northern southern hemisphere for small vertical scale gravity waves this is consistent with the preferred equatorward propagation of the wave indicated by a statistical analysis based on mst radar observations the ratio of potential to kinetic energy maximizes over the equator and decreases poleward the eliassen palm flux divergence associated with gravity waves is decelerative above the subtropical jet albeit small

sequence stratigraphic framework of the german triassic abstract the sequence stratigraphic methodology can be readily applied to the cratonic basin fill of the classic german triassic consisting of shallow marine to terrestrial mixed carbonate siliclastic rocks the whole triassic succession represents a second order transgression regression cycle built by third order depositional sequences systems tracts and parasequences many bounding surfaces represent widely used marker beds long used in classical lithostratigraphy using a synthesis of outcrop well log and literature data on stratal geometry facies cycle stacking patterns and paleogeography a regional chart of coastal onlap was constructed within the limitations of the presently available biostratigraphic data the observed cycles appear to correlate fairly well with those in other areas but include a number of additional sequences not included in the haq et al 1988 chart comparative analysis of regional onlap curves from different globally spread triassic basins together with an improved biostratigraphy will be necessary to relate the accommodation changes to eustatic versus tectonic and climatic controls and to produce a refined eustatic chart the german basin could provide a favourable reference point for such an analysis

post variscan evolution of the lithosphere in the rhine graben area constraints from subsidence modelling in the area of the cenozoic rhine rift system crustal and lithospheric thicknesses range between 24 and 35 km and 60 and 120 km respectively this rift system transects the deeply truncated variscan orogen and superimposed permo carboniferous wrench induced troughs and late permian and mesozoic thermal sag basins at the time of its westphlian consolidation the variscan orogen was probably characterized by 45 60 km deep crustal roots that were associated with its rheno hercynian saxo thuringian saxo thuringian bohemian and bohemian moldanubian sutures all of which are transected by the cenozoic rhine rift system during the stephanian early permian wrench induced disruption of the variscan orogen subducted lithospheric slabs were detached causing upwelling of hot mantle material during the resulting thermal surge partial delamination and or thermal thinning of the continental mantle lithosphere induced regional uplift at the same time the variscan orogenic roots were destroyed and crustal thicknesses reduced to 28 35 km in response to the combined effects of mantle derived melts interacting with the lower crust regional erosional unroofing of the crust and on a more local scale by its mechanical stretching towards the end of the early permian the potential temperature of the asthenosphere returned to ambient levels with this regional long term thermal subsidence of the lithosphere commenced controlling the development of a new system of late permian and mesozoic thermal sag basins however the evolution of these basins was repeatedly overprinted by minor short term subsidence accelerations that reflect the build up of far field stresses related to rifting in the tethyan and atlantic domains comparison of observed and modelled subsidence curves suggests that in the area of the rhine rift system the lithosphere had equilibrated with the asthenosphere at the end of the cretaceous at depths of 100 120 km before it became thermally destabilized again by cenozoic rifting and plume related magmatism modelled subsidence curves indicate that by the end of early permian times the thermal thickness of the remnant mantle lithosphere ranged between 10 and 50 km in areas that were later incorporated into mesozoic thermal sag basins this corresponds to mid permian thermal lithosphere thicknesses of 40 80 km the geological society of london 2004

late carboniferous to triassic reactivation of variscan basement in the western english channel evidence from onshore exposures in south cornwall south cornwall represents the westernmost part of the variscan basement massif in sw england field based investigations into the distribution geometry kinematics and relative chronology of post variscan deformation have been accompanied by preliminary palaeostress analyses these indicate three episodes of basement reactivation 1 stephanian to early permian nnw sse extension 2 early to late permian strike slip deformation and 3 late permian to triassic ene wsw extension these data have been used to test and refine previously published models based upon seismic and well data of late carboniferous to triassic basement reactivation and sedimentary basin development within the western approaches trough we confirm that nnw sse regional extension and reactivation of ene striking variscan thrusts had initiated by the latest carboniferous and that ene wsw regional extension and dip slip reactivation of nnw striking high angle faults occurred during the triassic permian strike slip deformation recognized onshore may have contributed to the development of widespread unconformities within the ovshore basins

quartz veins with associated sb pb ag au mineralization in the schwarzwald sw germany a record of metamorphic cooling tectonic rifting and element remobilization processes in the variscan belt a combination of textural observations from 38 permian sb pb ag au bearing quartz veins in the schwarzwald sw germany with isotopic fluid inclusion and geochemical data allows to refine genetic models for this common type of mineralization to understand the origin of mineralogical diversity and the correlation with large scale tectonic events textures record four main mineralization stages i fe as sb au ii pb zn cu iii pb sb and iv ag sb stage i sulfides dominated by pyrite and arsenopyrite formed due to cooling of low salinity metamorphic fluids during the permian with maximum homogenization temperatures of 400 c invisible gold in arsenopyrite pyrite marcasite and stibnite was remobilized and locally precipitated as electrum at the end of stage i minerals of stages ii and iii comprise a rich diversity of sb bearing sulfosalts including e g bournonite zinkenite and jamesonite this assemblage formed during jurassic times due to mixing of high salinity mid and upper crustal fluids up to 27 wt nacl cacl2 with homogenization temperatures between 50 and 250 c stage iii is marked by a rich variety of pb sb sulfosalts its local abundance is directly related to the presence of stage i mineralization and its extent of remobilization during a significant influx of pb in the jurassic cretaceous the formation of the upper rhine graben during the tertiary reactivated especially ne sw oriented veins percolating ag rich fluids reacted with earlier stage iii pb sb sulfosalts forming ag rich minerals stage iv such as miargyrite pyrargyrite and stephanite the transition from metamorphic fluids to basinal saline e g pb bearing brines over hundreds of millions of years as is shown in this study and present in other variscan occurrences indicates a possibly typical poly stage characteristic of sb deposits worldwide which has however not been investigated in detail so far

u th he evidence of jurassic continuous hydrothermal activity in the schwarzwald basement germany abstract u th he model and isochron ages of 21 botryoidal hematites collected from the hohberg base metal vein system in the triberg granite complex mittelschwarzwald germany cover most of the jurassic period the possibility of quantitative 4 he loss triggered by successive hydrothermal events although conceivable for individual hematites based on a 4 he retentivity study and calculated opening temperatures of hematite for 4 he of 90 180 c can largely be ruled out thus the range of model and isochron ages indicates that the majority of the hematites are not cogenetic this is supported by a broad range of pb total concentrations in the hohberg botryoidal hematites 150 2700 ppm by comparison with virtually identical pb total concentrations found in cogenetic hematites from four different vein systems in the schwarzwald the th u ratios of the hematites vary by a factor of 700 0 01 7 25 mainly as a result of the range of th concentrations 0 1 74 ppm the incorporation of substantial amounts of th in hematite is thought to result from increased th transport mobility possibly caused by association with colloids and or complexing in the ore solution 18 o analyses of a 160 ma old cogenetic hematite quartz pair indicate that precipitation occurred from a fluid of magmatic origin at a temperature of 180 c the regional temperature peak in the basement at the present erosional surface during the jurassic 130 c provides a lower temperature limit of hematite formation this implies that hematite emplacement occurred at temperatures roughly ranging between 130 and 180 c the jurassic continuous hydrothermal activity suggests that the pre rifting european craton is characterized by local thermal fluxes during a long time span

post variscan sedimentary record of the sw margin of the bohemian massif a review the late palaeozoic to cenozoic stratigraphic and structural record of the southwestern margin of the bohemian massif and its extension beneath the southward adjacent molasse basin shows that it is controlled by a system of basement involving faults which came into evidence during stephanian autunian times and which were subsequently repeatedly reactivated thick permo carboniferous clastics accumulated in fault bounded transtensional basins aligned with the southwestern bohemian border zone swbbz following late autunian deformation of these basins the swbbz was overstepped by late permian to late jurassic platform sediments reflecting tectonic stability during the early cretaceous the swbbz was strongly reactivated causing disruption and erosion of its mesozoic sedimentary cover sedimentation resumed in the area of the swbbz during late early and late cretaceous with clastic influx from the bohemian massif reflecting gradually increasing tectonic activity along the swbbz during the late senonian and paleocene transpressional deformations resulted in upthrusting of major basement blocks in the molasse basin such structures are sealed by transgressive late eocene marine strata mio pliocene uplift of the bohemian massif involving mild reactivation of the swbbz is related to the development of the volcano tectonic eger zone the structural configuration of the swbbz is largely the result of late senonian paleocene compressional intraplate tectonics which play a major role in the structural framework of the northern alpine and carpathian foreland

the thermal and mechanical development of the wessex basin southern england summary the wessex basin of southern england is an e w trending late palaeozoic to tertiary extensional basin formed on early palaeozoic variscan crust extension occurred over a protracted period from late carboniferous to cretaceous times resulting in the evolution of four main depocentres or sub basins the channel basin winterborne kingston trough vale of pewsey and weald basins each sub basin was controlled fundamentally by the normal reactivation of basement thrust faults and wrench or transfer faults the basement faults represent primary structures associated with the fold and thrust terrain of the devonian carboniferous variscan orogeny subsequent but synchronous reactivation of both thrust and transfer faults tended to compartmentalize the basement leading to discrete depocentres and the production of general rhomboidal shaped sub basins characteristic of pull apart basins in strike slip terrains to investigate the thermo mechanical properties of the lithosphere during basin formation 50 boreholes within the wessex basin were back stripped to isolate the driving tectonic subsidence responsible for basin formation the resultant driving subsidence is characterized by a gentle sometimes negative exponential form with superimposed rapid discrete subsidence events as the geological development of the wessex basin was characterized by polyphase extension and the utilization of crustal detachments the lithospheric model used to determine crustal extension above the detachment and stretching below the detachment included the effects of depth dependent stretching and finite re rifting from the back stripping analysis the basin wide averaged upper crustal extension and lower crustal sub crustal lithospheric stretching were 11 and 5 respectively the distribution of is strongly influenced by the location of growth faults and hence basement thrust fault reactivation suggesting that is reflecting the brittle failure and collapse of hanging wall blocks repeated slip and block collapse resulted in the polyphase extension responsible for renewed basin subsidence in contrast is uniformly distributed across the basin suggestive of a ductile failure of the lower crust and responsible for the low magnitude thermal subsidence strain compatibility between the upper crust and lower crust sub crustal lithosphere is maintained partly within the basin 5 and partly external to the basin as the variscan basal thrust was the fundamental relay in the sense of wernicke responsible for the wessex basin formation we postulate that strain balancing induced a cumulative essentially thermal isostatic uplift of 60 m under the northern margin of the armorican massif

architecture and kinematics of the constance frick trough northern switzerland implications for the formation of post variscan basins in the foreland of the alps and scenarios of their neogene reactivation post variscan basins are commonly inferred to represent important precursor structures of later extensional and contractional tectonic events in the foreland of the european alps nevertheless their structural characteristics are typically poorly constrained our investigation sheds new light on the architecture and kinematics of the constance frick trough cft in northern switzerland according to our analysis of an extensive and revised 2 d reflection seismic data set the ene wsw striking cft is divided into an eastern segment and a western segment characterized by opposing half graben geometries the transition between the two segments coincides with the prolongation of a preexisting wnw ese trending strike slip fault zone exposed in the adjacent black forest massif to the north field based analysis of outcrop scale faults in the latter area implies that the minimum horizontal stress during the formation of the cft was roughly oriented ne sw which is oblique to the trough axis while previously published analogue models imply that some characteristics of the cft could be explained by lateral linkage of graben segments under oblique extension the pronounced half graben geometry of the cft suggests that low angle normal faulting may also have contributed to trough formation the observed structural complexities of the cft and uncertainties regarding its deep structure must be taken into account for interpretations of similar late paleozoic basins inferred in the subsurface of the northern alpine foreland basin in particular concerning scenarios of their neogene reactivation during alpine orogeny

4he age discordance and release behavior of a double shell botryoidal hematite from the schwarzwald germany abstract microprobe analyses of a double shell botryoidal hematite from the fahlenbach vein system schwarzwald germany show an fe3 depletion of 3 4 with respect to al3 and silicon within a 0 5 mm wide zone of alteration which separates both shells and probably is the result of a subsequent hydrothermal event induced 235u fission tracks of grain mounts from both shells reveal several grain populations within a range of 3 to 22 ppm total uranium mass spectrometer u and photometer analyses th of various localities probed within each shell vary significantly at about 5 and 12 ppm u as well as at 11 and 19 ppm th the th u ratios vary from 1 5 to 2 4he concentrations correlate with u 0 23 th heterogeneities which permits construction of two shell internal isochrons the 4he ages are discordant inner shell although mineralogically older 150 ma outer shell 182 ma 4he release by stepwise heating of one sample from each shell yielded activation energies of 124 8 and 142 7 kj mol the extrapolated 4he diffusion coefficients at 20 c logd 20 r 2 values of 19 7 0 7 and 22 2 0 6 sec 1 reveal a higher 4he retentivity at earth s surface temperatures for the outer shell 4he closure temperatures after dodson 1973 are lower for the inner shell hematite by 50 c probably also indicating earlier opening during heating the age discordance could be the result of a younger hydrothermal event which probably also has caused the observed alteration zone such an event is potentially related to the emplacement of the nearby rappenloch hematite generation ii 156 ma ago complete rejuvenation of the inner shell hematite had occurred whereas the 4he age of the outer shell was only slightly lowered due to the higher 4he retentivity

three dimensional waveform modeling of ionospheric signature induced by the 2004 sumatra tsunami 1 the sumatra december 26th 2004 tsunami produced internal gravity waves in the neutral atmosphere and large disturbances in the overlying ionospheric plasma to corroborate the tsunamigenic hypothesis of these perturbations we reproduce with a 3d numerical modeling of the ocean atmosphere ionosphere coupling the tsunami signature in the total electron content tec data measured by the jason 1 and topex poseidon satellite altimeters the agreement between the observed and synthetic tec shows that ionospheric remote sensing can provide new tools for offshore tsunami detection and monitoring

the global reach of the 26 december 2004 sumatra tsunami numerical model simulations combined with tide gauge and satellite altimetry data reveal that wave amplitudes directionality and global propagation patterns of the 26 december 2004 sumatra tsunami were primarily determined by the orientation and intensity of the offshore seismic line source and subsequently by the trapping effect of mid ocean ridge topographic waveguides

simultaneous normal faulting and extensional flexuring during rifting an example from the southernmost upper rhine graben the southern end of the upper rhine graben urg is formed by a major continental transfer zone which was localised by the reactivation of ene oriented basement faults of late palaeozoic origin a combination of subcrop data derived from exploration wells and reflection seismic lines and palaeostress analysis provided new constraints on the timing and kinematics of interacting basement faults rifting in the southern urg began in the upper priabonian under regional wnw ese directed extension oriented roughly perpendicular to the graben axis in the study area this led to the formation of nne trending half grabens simultaneously ene trending basement faults situated in the area of the future rhine bresse transfer zone rbtz were reactivated in a sinistrally transtensive mode in the sedimentary cover the strike slip component was accommodated by the development of en echelon aligned extensional flexures flexuring and interference between the differently oriented basement faults imposed additional but locally confined extension in the sedimentary cover which deviated by as much as 90 from the regional wnw ese extension the interference of regional and local stresses led to a regime approaching radial extension at the intersection between the urg and rbtz

implied basement tectonic control on deposition of lower carboniferous carbonate ramp southern cordillera canada cambrian kanasevich et al 1969 and prethe mount head embayment is a regional downwarp along the west coast of lower middle devonian norris and price 1966 carboniferous western canada that developed by differential subsidence which we recog benvenuto and price 1979 nize from lithostratigraphic and biostratigraphic patterns palinspastic restoration of the mount head embayment illustrates that subsidence domains are geometrically coincident with previously identified tectonic elements of the autochthonous basement thus it ap methods pears that basement tectonic elements controlled sediment accommodation and accumu geologic observations were recorded on lation within the mount head embayment the overall shape of this embayment is probably palinspastically restored maps and cross setinherited from the arcuate shape of the late proterozoic cratonic rift margin within the tions and to basement tectonic mount head embayment several northeast southwest trending archean and proterozoic domains defined on aeromagnetic and gravbasement tectonic elements intersect the autochthonous cratonic margin at high angles ity maps brandley 1993 the palinspastic carboniferous piano key like structural reactivation of these tectonic elements produced base map is modified from gibson s 1985 oriented trends of differential subsidence that partitioned the mount head embayment into map of displacement vectors for jurassic two subbasins crowsnest and kananaskis depocenters separated by a more positive area rocks the magnitudes of the vectors were highwood high moreover our data imply that precambrian basement structure noted by others under the plains and rocky mountain fold and thrust belt continued across the altered to reflect displacements at the misrocky mountain trench to the west and that tectonic control on sedimentation noted by sissippian level documented by bally et al others for precambrian and pre middle devonian rocks extends clearly into overlying 1966 price 1981 and price and fermor carboniferous deposits 1985 university theses and geological survey of canada maps and sections across

the ups and downs of tectonic quiescence recognizing differential subsidence in the epicontinental sea of the oxfordian in the swiss jura mountains abstract recent studies in northern switzerland have shown that epicontinental areas thought to have been tectonically stable during the mesozoic were not necessarily as rigid as presumed by comparing oxfordian facies boundaries and depocenters in their palinspastic position with known faults in the basement a direct relationship between the two can be demonstrated previously the lack of obvious synsedimentary tectonic features has lulled scientists into believing that the realm of the swiss jura was tectonically stable during the mesozoic however it can be shown that facies and sedimentary structures are largely influenced by tectonics subsurface data provide evidence for the presence of paleozoic troughs in the basement which apparently were prone to reactivation during the pan european stress field reorganization taking place in the late jurassic this led to differential subsidence along pre existing lineaments within the study area which can be recognized in the distribution of oxfordian epicontinental basins and their coeval shallow water counterparts eustatic sea level fluctuations played an important role in the development of shallow water facies patterns but a subordinate role in the control of accommodation space in basins while tectonic activity is often recorded in the sedimentary record in the form of platform break ups and associated sedimentary debris more subtle indicators may be overlooked or even misinterpreted sedimentary structures and isopach maps as well as subsurface data in the study area suggest that subtle synsedimentary tectonic movements led to the formation of two shallow diachronous epicontinental basins during the late jurassic it becomes possible to recognize and differentiate the combined effects of local and regional tectonism eustasy and sedimentation

interaction of permo triassic and jurassic extensional fault blocks during the development of the northern north sea the main structural elements resulting from late permian early triassic extension have been resolved across the total width of the northern north sea the northern segment of the basin north of 61 n bounded to the west by the hutton fault and to the east by the norwegian mainland was occupied by four westerly tilted half grabens 25 35 km in width prior to jurassic extension the central segment of the basin 60 20 61 n exhibits a full graben beneath the jurassic horda platform flanked by half grabens tilted towards the basin margins the change in permo triassic fault block configuration defining structural domains is largely constrained by a basement discontinuity which runs diagonally ne sw across the basin maximum jurassic extension is represented by several centres of subsidence aligned nne ssw across a n s oriented and broader permo triassic basin jurassic extension was concentrated within the viking graben proper south of 60 n which in this area is represented by single westerly tilted en echelon half graben segments 20 25 km wide the area affected by jurassic extension becomes progressively wider to the north again governed by the basement discontinuity eventually encompassing the total width of the basin c 200 km north of 61 n the central segment of the northern north sea displays the greatest contrast in permo triassic and jurassic structural styles and basin geometry jurassic stretching and faulting was negligible to the east horda platform precisely the area which had been the site of maximum permo triassic stretching and fault activity it has generally been assumed that jurassic fault configuration along the eastern margin of the central segment of the viking graben to a large extent reflects the reactivation of major permo triassic faults this study demonstrates the interference of permo triassic and jurassic basin geometries in this area due to major faults of the two generations dipping in opposite directions as a consequence the e tilted oseberg fault block of jurassic origin and c 20km in width is underlain by a wider c 35 km and w tilted permo triassic fault block

north german zechstein facies patterns in relation to their substrate an attempt was made to relate the early zechstein facies distribution to the zechstein substrate comparable developments in the hessian trough and along the lower rhine embayment allow for the assumption that the creation of depocenters in the weser ems area are governed by interrelated late saalic tectonic pulses due to differences in the architecture and mobility of the substrate variations in the depositional model must be assumed

analytical method for estimating palaeowave climate and water depth from wave ripple marks analytical expressions are developed for evaluating palaeodepth and palaeowave conditions from wave ripple marks palaeodepth and palaeowave climate estimates can be extremely powerful predictors in reconstructions of vertical movements related to basin subsidence local and regional ancient wave climate trends and the basin shape the analytical expressions developed herein are applied to wave ripple marks preserved in the lower marine molasse of switzerland western austria and southern germany the results suggest that in contrast to traditional concepts of an eustatic sea level change the lower marine molasse regression was a result of mainly depositional processes the subsidence rate greatly exceeded the rate of sea level fall over a wide geographical area furthermore the widening of the lower marine molasse basin to the ene is well documented by the increase of the ancient wave period and wave power calculated from wave ripple marks found in storm deposits

the fossil geothermal system of the baden baden trough northern black forest f r germany abstract limnic sediments of the upper carboniferous lower permian and triassic from the baden baden trough were hydrothermally altered during the jurassic concentric alteration halos each having a characteristic mineral composition were formed from center to margin zones of sericitization albitization and weak alteration covering an area of 100 km2 are evident these zones indicate decreasing hydrothermal influence whereby the solutions must have risen in the center the chemistry of mica changing systematically from a muscovitic toward an illitic composition also reflects this trend the boron content increases from 75 to 205 ppm the estimated maximum alteration temperature ranges between 240 and 290 c these remarkable changes are obviously early manifestations of geothermal events related to the development of a continental rift rhine graben

the palaeozoic evolution in the alps from gondwana to pangea more than 50 of the alps expose fragments of palaeozoic basement which were assembled during the alpine orogeny although the tectonic and metamorphic history of the basement units can be compared to that of the variscan crust in the alpine foreland most of the basement pieces of the alps do not represent the direct southern continuation of variscan structural elements evident in the massif central the vosges black forest or the bohemian massif the basement units of the alps all originated at the gondwana margin they were derived from a precambrian volcanic arc suture fringing the northern margin of gondwana from which they were rifted during the cambrian ordovician and silurian a short lived ordovician orogenic event interrupted the general rifting tendency at the gondwana active margin after the ordovician the different blocks drifted from the gondwana margin to their pangea position colliding either parallel to armorica with laurussia or with originally peri gondwanan blocks assembled presently in armorica from the devonian onwards many basement subunits underwent the complex evolution of apparently oblique collision and nappe stacking docking started in the external massifs the penninic and lower and middle austroalpine units in approximately devonian early carboniferous times followed by the upper austroalpine and the south alpine domains in the visean and the namurian times respectively wrenching is probably the best mechanism to explain all syn and post collisional phenomena since the visean followed by post orogenic collapse and extension it explains the occurrence of strike slip faults at different crustal levels the formation of sedimentary troughs as well as the extrusion and intrusion of crustal and mantle derived magmas and allows for contemporaneous rapid uplift of lower crustal levels and their erosion from the stephanian onwards all regions were deeply eroded by large river systems

post variscan to early alpine sedimentary basins in the tauern window eastern alps the crystalline basement of the tauern window is locally covered by palaeozoic to mesozoic sediments that experienced alpine tectonometamorphism the sedimentary cover has been subdivided into mappable lithological units the correlation of these units the use of some dated marker intervals and independent palinspastic restoration provide evidence that the depositional area was differentiated into basins and swells at the end of the variscan orogeny during the carboniferous and permian intermontane basins formed in basement rocks and mainly continental clastics accumulated in elongate troughs later probably during the triassic there was levelling of the previous relief and subsidence of the basins but continental sedimen tation still prevailed although interrupted by some marine transgressions thereafter probably during the jurassic the area was progressively flooded and the sedimentation became increasingly calcareous the upper jurassic carbonates document complete submergence in some areas the upper jurassic carbonates directly rest on crystalline basement indicating renewed tectonic stretching the sedimentary cover shows striking similarities with coeval deposits within the germanic basin and the study area is therefore considered to have been part of the southern european continental margin of the tethys the so called vindelician land

normal modes modelling of post seismic ionospheric oscillations since 1960 several experiments have shown strong perturbations of the ionosphere after earthquakes for the biggest quakes doppler ionospheric soundings have revealed displacements of several tens of meter of the ionized layers e and f an accurate modelling of these phenomena was however never described we present here synthetic displacements of such oscillations and compare it with experimental data realistic models of the atmosphere including viscosity are used as well as realistic earth and seismic source model these ionospheric oscillations are computed by normal modes summation taking explicitly into account the coupling between the solid earth and the open atmosphere they are associated to the rayleigh fundamental surface waves we obtain a good agreement between synthetics and observations so it should be possible to use this method to study the ionospheric post seismic perturbations and possibly the high altitude profile of the density and the viscosity of the atmosphere

did tsunami launched gravity waves trigger ionospheric turbulence over arecibo 1 we report on measurements of ionospheric plasma dynamics conducted at the arecibo observatory between 20 00 and 24 00 local time lt on december 25 and 26 2004 using the 430 mhz incoherent scatter radar isr for interpretive purposes these measurements are supported by data from two nearby ionosondes and global positioning system gps satellites the isr detected different ionospheric behaviors during the vertical transmission periods on the consecutive magnetically quiet nights on the night of december 25 the ionosphere descended smoothly and spread f signatures faded for about two hours on the following evening the bottomside ionosphere rose by 50 km inducing plasma irregularities and intense spread f alternating cycles of bottom side plasma rising and falling persisted through the remainder of the experiments we postulate that this sinusoidal behavior is a response to gravity waves propagating above puerto rico nearly simultaneous data from two nearby stations show that gps signals were modified by variations in total electron content tec indicating the presence of traveling ionospheric disturbances tids the december 26 experiments were conducted about a day after an mw 9 2 earthquake launched tsunami waves first across the indian then into the atlantic and pacific oceans we suggest that coupling at the tsunami sea air interface launched gravity waves that propagated for great distances beneath the mesopause gps data recorded tec variation in asia europe and the caribbean suggesting that tids were induced on a global scale at the wake of tsunami launched gravity waves energy from imperfectly ducted gravity waves leaked into the ionosphere partially over puerto rico the wind velocity field of these gravity waves caused local ionospheric plasma to rise seeding bottomside irregularities via the generalized rayleigh taylor instability

late visean hidden basins in the internal zones of the variscan belt u pb zircon evidence from the french massif central u pb zircon ages from volcanic rocks interbedded in two upper carboniferous basins of the variscan massif central france document the presence of an unexpected late visean sedimentary sequence zircons extracted from a fireclay at the base of the sedimentary pile in the bosmoreau basin provide an age of 332 4 ma identical to the 333 2 ma age obtained from a rhyolitic lava sampled in the decazeville basin in addition both volcanic rocks contain inherited or xenocrystic zircons reflecting the ages of the basement and or source components the bosmoreau fireclay contains a limited amount of xenocrystic zircons having ages of ca 390 400 ma whereas inheritance is much more abundant in the decazeville rhyolite which includes a mesoproterozoic source component 1 0 ga the ca 330 ma ages demonstrate that these two basins with mainly stephanian sedimentary infill were actually initiated during the late visean and are the first known upper crustal evidence of the visean westphalian extensional event recognized previously only in midcrustal plutonic bodies moreover the location of these basins in the hanging wall blocks of two major fault systems i e the argentat and sillon houiller faults suggests a genetic link between fault motion and basin opening as early as the late visean these results indicate that magmatism and associated volcanism block movement along major crustal scale faults erosion and basin opening were contemporaneous and shed new light on the visean westphalian synconvergent extension that was previously understood only as a deep seated event