extracting time domain green s function estimates from ambient seismic noise 1 it has been demonstrated experimentally and theoretically that an estimate of the green s function between two seismic stations can be obtained from the time derivative of the long time average cross correlation of ambient noise between these two stations this tdgf estimate from just the noise field includes all tensor components of the green s function and these green s function estimates can be used to infer earth structure we have computed cross correlations using 1 to 30 continuous days of ambient noise recorded by over 150 broadband seismic stations located in southern california the data processing yielded thousands of cross correlation pairs for receiver separations from 4 500 km which clearly exhibit coherent broadband propagating dispersive wavetrains across frequency band 0 1 2 hz

new constraints on the 3d shear wave velocity structure of the upper mantle underneath southern scandinavia revealed from non linear tomography abstract we analyse travel times of shear waves which were recorded at the magnus network to determine the 3d shear wave velocity vs structure underneath southern scandinavia the travel time residuals are corrected for the known crustal structure of southern norway and weighted to account for data quality and pick uncertainties the resulting residual pattern of subvertically incident waves is very uniform and simple it shows delayed arrivals underneath southern norway compared to fast arrivals underneath the oslo graben and the baltic shield the 3d upper mantle vs structure underneath the station network is determined by performing non linear travel time tomography as expected from the residual pattern the resulting tomographic model shows a simple and continuous vs perturbation pattern a negative vs anomaly is visible underneath southern norway relative to the baltic shield in the east with a contrast of up to 4 vs and a sharp w e dipping transition zone reconstruction tests reveal besides vertical smearing a good lateral reconstruction of the dipping vs transition zone and suggest that a deep seated anomaly at 330 410 km depth is real and not an inversion artefact the upper part of the reduced vs anomaly underneath southern norway down to 250 km depth might be due to an increase in lithospheric thickness from the caledonian southern scandes in the west towards the proterozoic baltic shield in sweden in the east the deeper seated negative vs anomaly 330 410 km depth could be caused by a temperature anomaly possibly combined with effects due to fluids or hydrous minerals the determined simple 3d vs structure underneath southern scandinavia indicates that mantle processes might influence and contribute to a neogene uplift of southern norway

seismic structure and composition of the crust beneath the southern scandes norway abstract new results on p and s wave seismic velocity structure in southern norway indicate that the crust has an average poisson s ratio of 0 25 is predominantly of felsic intermediate composition and lacks a significant mafic lower crust a crustal scale refraction seismic study magnus rex mantle investigations of norwegian uplift structure refraction experiment acquired data along three 300 to 400 km long active source seismic profiles across the southwest scandinavian domain in southern norway the youngest section of the fennoscandian shield moho depths in the domain are 36 40 km thinning towards the continental shelf and oslo graben the high vp lower crust beneath the southwest scandinavian domain vp 7 km s is around 4 km thick crustal structure in the adjacent svecofennian domain differs significantly moho depths reach 50 km and an up to 24 km thick high vp lower crust is present strong p and s wave arrivals are recorded from magnus rex from which poisson s ratio for the crust is calculated the unusually strong s wave arrivals allow rare insight into crustal poisson s ratio structure that is not commonly available from active source data the thinness of the mafic lower crust in southern norway is in significant contrast to other parts of the fennoscandian shield and delamination or convective removal of the lower crust is proposed tectonic events that may have triggered detachment of the lower crust include extensional collapse after the caledonian orogeny and permian extension

heat flow and thermal structure of the lithosphere across the baltic shield and northern tornquist zone abstract terrestrial heat flow data from archean and proterozoic provinces of the baltic shield its southwestern margin and the tectonic transition to the younger tectonic units of central europe northern segment of the european geotraverse are compiled and examined for local and regional variations a 2 d numerical lithospheric temperature and heat flux model is presented covering 1800 km of the deep seismic fennolora profile across the baltic shield and 500 km of eugeno s northern eugemi seismic lines across the northern tornquist zone and the danish and north german basins thermal lithosphere defined as the outer layer with relatively low temperatures t c in which heat transfer is dominantly by conduction is found to vary markedly in thickness from 85 110 km beneath basins and tornquist zone to about 150 km in central shield areas and 200 250 km in areas of low heat flow along the northern shield profile these results are in very good agreement with seismological information from surface wave dispersion analysis and the refraction wide angle seismic interpretation of fennolora data the combined thermal and seismologic evidence indicates that the uppermost mantle region stratified in seismic velocity is restricted to the upper relatively cold thermal layer which is interpreted to constitute shield lithosphere local and to some extent regional variations in surface heat flow are found to be closely related to variations in near surface radiogenic heat production for the southern baltic shield a heat flow heat production relationship of q 0 32 8 7 6 h 0 is derived regional increase in heat flow from northern and central shield provinces to the shield margin and the tornquist zone is interpreted to be related partly to differences in upper crustal heat generation partly and in southernmost areas mainly to an increased heat flux from the upper mantle upper mantle heat flux is estimated at 20 25 mw m 2 along the northern and central shield transect increasing to 30 40 mw m 2 beneath the shield margin basins and tornquist zone lithospheric thickness variations in this region of northern europe are found to be closely associated with variations in heat flux from the uppermost mantle and perhaps to a large extent controlled by geodynamically determined lateral differences in upper mantle heat flux earthquake focal depth data and information on crustal strength show baltic shield seismicity to be limited generally to the upper 20 25 km brittle part of the crust at temperatures less than 300 400 c maximum source depth of magnetic anomalies at temperatures near 600 c is in the deepest part of the crust near the crust mantle boundary in the southern region about 25 km depth along the tornquist zone and about 35 40 km in southern shield areas and in the uppermost mantle 60 70 km depth in the northern shield areas some petrologic implications are discussed the present deep crust is supposed to be at lower temperature pressure conditions than at early stages of formation however also the present deepest parts of the shield crust 35 40 km are within the stability field of eclogites the general absence of significant gravity anomalies in areas of marked crustal thickness variations indicate high density eclogites to be present in significant amounts in the deep shield crust

integrated geophysical modelling of a lateral transition zone in the lithospheric mantle under norway and sweden summary the scandinavian mountain chain the scandes exhibits characteristics that are unusual for an old palaeozoic mountain belt these include renewed neogene uplift in a passive margin setting and the lack of a pronounced crustal root we investigate the influence of present day thermal compositional and geometric structures in the crust and mantle on the topography of the southern scandes and the resulting implications for the tectonic history of fennoscandia a self consistent 3 d subsurface model of southern norway and sweden is constructed from recent geophysical data sets that constrain the crustal architecture lithosphere geometry density distributions and thermal properties recent seismological studies show evidence for a relatively abrupt transition from seismically slower lithospheric mantle underneath southern norway to seismically faster lithospheric mantle underneath southern sweden we find that a transition from thin subcontinental lithospheric mantle sclm underneath southern norway to a significantly thicker sclm beneath southern sweden can explain this velocitytrend adifferenceincompositionbetweenthetwosclmdomains owingtodifferent depletion refertilization is required to satisfy the gravity field and isostatically compensated topography but contributes only slightly to the observed velocity contrast such a lateral transition zone constituting a major change in the lithospheric structure in southwestern fennoscandia can be related to several major proterozoic and phanerozoic tectonic events such as the sveconorwegian orogeny the permian oslo rift and perhaps even the opening of the atlantic

radon 222 in medicinal groundwaters of szczawno zdroj sudety mountains sw poland radon is a significant component of the groundwaters that discharge in the springs of szczawno zdroj and are recognized as medicinal however among the five exploited springs adjoining each other it is only in marta spring that radon occurs in large concentrations up to 325 6 bq dm3 therefore the authors have made an attempt to describe and clarify this fact they found out from their own research and archival data that 222rn dissolves in the waters of marta spring after acidulous waters of deep circulation have mixed with poorly mineralized shallow waters in their outflow zone the genesis of the gas is determined by the content of its parent nuclide 226ra in the sandstones in the vicinity of the intake the volume of the rocks providing radon to the waters of this intake has been estimated at several hundred cubic metres no seasonal fluctuations in radon concentration have been observed and 222rn concentration changes do not seem to be influenced by changes in the concentration of other chemical components of the waters or by the discharge of the intake the process of dissolving 222rn in the medicinal groundwaters of marta spring is the last the shortest and the most local of the processes that form the chemical composition and the physical properties of these waters

abstract reflectance of vitrinite like maceral derived from benthic multicellular algae as organic maturity indicator for pre silurian marine strata

petroleum source in the tazhong uplift tarim basin new insights from geochemical and fluid inclusion data abstract a total of 108 drill stem test dst crude oil samples and 10 reservoir fluid inclusion samples were investigated geochemically to identify the characteristics and origin of the crude oil in the tazhong uplift tarim basin nw china results show that the majority of oils share typical biomarker characteristics from the middle upper ordovician o2 3 source rock and related crude oil features these features include a distinct v shape in the relative abundance of c27 c28 and c29 regular steranes and low abundances of dinosterane 24 norcholestanes triaromatic dinosteroids and gammacerane only a few oils display typical biomarker features indicating a cambrian lower ordovician o1 genetic affinity such as linear or anti l shape c27 c28 and c29 regular sterane distributions and relatively high concentrations of dinosterane 24 norcholestanes triaromatic dinosteroids and gammacerane it appears that most of the oils studied were derived from the o2 3 intervals as suggested by previous studies however the 13c values of individual n alkanes indicate that most of the crude oils in the tazhong uplift represent a mixture of two end member oils an o1 derived oil such as from well td2 or tz62 s and an o2 3 derived oil such as from well ym2 the data suggest that most of the oils in the uplift have a mixed origin and do not originated from the middle upper ordovician strata alone this conclusion is supported by data on the molecular composition of petroleum inclusions this new oil mixing model is critical for reconstructing the hydrocarbon formation and accumulation history for the region and may have important implications for further petroleum exploration in the tarim basin

uranium mineralization in the alum shale formation sweden evolution of a u rich marine black shale from sedimentation to metamorphism the alum shale formation is a metal rich black shale deposited on the baltoscandian platform between middle cambrian and early ordovician these black shales may be of particular economic interest for their relatively high uranium content 100 300 ppm and their wide distribution from norway to estonia scandinavian alum shale may thus constitute a great potential resource of uranium as a low grade ore the alum shale formation is particularly interesting to study the mineralogical expression and content of uranium in series submitted to progressive burial and metamorphism for this purpose the behavior of u p ti and organic matter was studied on a series of representative samples from most alum shale prospection zones in southern sweden where alum shale underwent fairly shallow burial uranium concentrations have no mineralogical expression except a rather high u content of biogenic phosphates calcite concretions beefs and fractures recorded the migration of hot overpressured hydrocarbons and brines from thermally mature areas to immature alum shale however thermal maturation and fluid migration did not allow remobilization of uranium and metals at the opposite in northern sweden where the series were folded duplicated and submitted to low grade greenschist metamorphism during caledonian orogeny phospho silicates u si ca p ti zr y and minor amounts of uraninite are identified and indicate that u p and ti were mobile and precipitated as new phases the effect of metamorphism is therefore important to consider as the leachability of u especially during bio hydrometallurgical processes which will be by far different between the two considered areas

seismic modelling of the norwegian danish basin along a refraction profile in northern jutland abstract the seismic velocity of the sedimentary structure of the norwegian danish basin and its underlying precambrian basement have been modelled by 2d ray tracing interpretation of a 200 km section of a deep refraction seismic profile in northern jutland eugeno s project profile 3 a model is presented which satisfies the quite detailed prior geological information from wells and shallow reflection seismic interpretations for the upper sedimentary layers and the traveltime observations from three shotpoints along the profile the model shows a basin thickness of about 7 km in the southern part of the profile thinning to 1 5 2 km in the northern part towards the fennoscandian border zone in the central part the model thickness is about 10 km sedimentary p wave velocities vary from 1 9 to 3 8 km s in the upper layers quaternary tertiary and upper cretaceous units to about 5 5 km s in the deepest palaeozoic unit the precambrian basement shows velocities of 5 9 6 5 km s there is a clear indication of a basement reflector at depths of 11 km velocity contrast 6 0 6 4 km

ground water geochemistry of 228ra 226ra and 222rn abstract 228ra 226ra and 222rn activities were determined on over 150 ground water samples collected from drilled public water supply wells throughout south carolina a wide range of aquifer lithologies were sampled including the crystalline rocks of the piedmont and sedimentary deposits of the coastal plain a significant linear relationship between log 228ra and log 226ra n 182 r 0 83 was indistinguishable between piedmont and coastal plain ground water median 228 ra 226 ra activity ratios for the piedmont 1 2 and coastal plain 1 3 ground water are close to estimated average crustal 232 th 238 u activity ratios of 1 2 to 1 5 corresponding to th u weight ratios of 3 5 to 4 5 a linear correlation was also found between log 222rn and log 226ra for piedmont n 68 r 0 62 and coastal plain n 89 r 0 64 ground water however the median 222 rn 226 ra activity ratio for piedmont ground water 6100 was much higher than for coastal plain ground water 230 higher excess 222rn activities may be due to greater retention of 226ra by the chemically active piedmont aquifers compared to the more inert sand aquifers sampled in the coastal plain the relationship between log 228ra and log 226ra was used to predict total ra 228 ra 226 ra distributions in appalachian and atlantic and gulf coastal plain ground water predictions estimate that 2 4 of appalachian and 5 3 of atlantic and gulf coastal plain ground water supplies contain total ra activities in excess of the 5 pci l limit established by the u s environmental protection agency these predictions also indicate that 40 50 of these ground water wells may be overlooked using the presently suggested screening activity of 3 0 pci l of 226ra for 228ra analysis

wave theoretical inversion of teleseismic surface waves in a regional network phase velocity maps and a three dimensional upper mantle shear wave velocity model for southern germany summary using teleseimic surface wave data from 110 selected earthquakes recorded at 10broad band stations in southern germany we construct phase velocity maps of rayleigh waves for southern germany in a further step these maps are inverted for a three dimensional model of the sv velocity of the upper 200 km of the mantle we attempt to take into account the effect of heterogeneous structure outside the study region by jointly inverting the data for heterogeneous phase velocity inside the study region and the distortion of the incoming wavefields by the surrounding structure the total wavefield in the study region is computed with a scattering formalism which includes multiple forward scattering and single backscattering since in principle the data can be perfectly fit by the incoming wavefields without any heterogeneous structure inside the study area we impose additional constraints on the incoming wavefields to reduce the non uniqueness the most important constraint is an energy criterion which states that the energy of the modelled wavefield in the study area averaged over many events should be equal to the energy sampled by the stations we demonstrate that enforcing this criterion generates phase velocity maps with heterogeneous structure nevertheless we are able to satisfy the energy criterion without any heterogeneous structure at the price of an only slightly increased data misfit hence it must be concluded that a seismic network of size and station density such as the one used in this study is still insufficient to demonstrate convincingly the existence of heterogeneities in the network area using teleseismic surface waves any reasonable structure combined with the appropriate incoming wavefields would allow an acceptable fit of our data this frustrating conclusion of course applies to all other comparable studies which use teleseismic surface waves although we cannot convincingly show that any phase velocity map we find should be preferred over others we are able to obtain good reconstructions of test structures from realistic synthetic data with the same station and event distribution as the real data moreover we find that the geometric pattern of the phase velocity maps obtained from real data depends only weakly on the constraints applied in the inversion while the amplitude of the phase velocity perturbations is almost completely determined by the constraints for all periods considered the fit to the data is extremely good the reduction of the quadratic misfit relative to the case of plane incoming waves and no structure is dramatic for the shorter periods the 3 d model of vertical shear wave velocity down to a depth of 200 km exhibits a basic division into four quadrants separated by a vertical plane intersecting the surface along a nearly west east line and a horizontal plane at about 130 km depth the northern rants show high velocities in the top 120 km and low velocities below 140 km the opposite is the case for the southern quadrants an exception to this general feature is a pronounced low velocity zone in the northwestern corner of the region

seismic velocities and anisotropy of the lower continental crust a review seismic anisotropy is often neglected in seismic studies of the earth s crust since anisotropy is a common property of many typically deep crustal rocks its potential contribution to solving questions of the deep crust is evaluated the anisotropic seismic velocities obtained from laboratory measurements can be verified by computations based on the elastic constants and on numerical data pertaining to the texture of rock forming minerals for typical lower crustal rocks the influence of layering is significantly less important than the influence of rock texture surprisingly most natural lower crustal rocks show a hexagonal type of anisotropy maximum anisotropy is observed for rocks with a high content of aligned mica it seems possible to distinguish between layered intrusives and metasediments on the basis of in situ measurements of anisotropy which can thus be used to validate different scenarios of crustal evolution

teleseismic surface wave study for s wave velocity structure under an array southern california summary teleseismic surface wave data from the dense seismographic network in southern california cisn california integrated seismic network are used to construct s wave velocity maps for the region surface wave phase velocity measurements are achieved by way of a waveform matching spectral domain technique that was developed for use within the cisn array a two station phase velocity measurement technique was developed which takes advantage of the fact that for surface wave arrivals from any azimuth there are multiple pairs of cisn stations which are almost exactly on the same great circle paths to ensure the validity of this assumption particle motions were analysed for measured pairs within the network showing that the deviation between expected backazimuth from ray theory and observed backazimuths are small enough to be analysed by a simple distance correction this method was applied to 114 large earthquakes for time periods between 1999 and 2002 and led to the retrieval of phase velocity maps for rayleigh waves between 20 and 55 mhz and for love waves between 25 and 45 mhz finite frequency effect for propagating surface waves was approximately taken into consideration using a geometrical technique an ellipse determined by wavelength and great circle distance between the source and receiver can describe an influence zone for the finite frequency effect phase velocity map reconstructions using a method which incorporates this effect show minimal changes in phase velocity maps for our region but do extend solvable velocity regions inversion for s wave velocity distribution with depth shows that deep structural contrast across the san andreas extends into the upper mantle a slow velocity anomaly is evident under the southern sierras and the salton sea the latter region indicating the northward extension of tectonic activity in the gulf of california fast velocity roots that reach 60 km are found under the western part of transverse ranges and the northern peninsular ranges reconstruction of past location of the western transverse range microplate implies that these two ranges may have been adjacent to one another historically both the western transverse range fast velocity root and the peninsular range fast velocity root may be a remnant of old oceanic plate

a dynamical model for generating sharp seismic velocity contrasts underneath continents application to the sorgenfrei tornquist zone new seismic velocity models based on teleseismic traveltime tomography show a sharp lithospheric boundary at the sorgenfrei tornquist zone stz between 100 and 250 km depth with p waves about 4 faster and s waves 6 faster within the cratonic lithosphere to the north experiments and thermodynamic calculations indicate that seismic velocity differences in the shallow mantle down to the transition zone must be mostly of thermal origin as typical mantle rocks are characterized by similar velocities based on composition alone we propose a dynamical model of convection in the upper mantle that is consistent with rheological data and that satisfies the seismic observations by maintaining an abrupt lateral temperature contrast over hundreds of myrs a step like increase in lithospheric thickness from 100 to 250 km is assumed to have formed in a triassic rifting event at the stz around 220 ma and is subsequently exposed to active convection below a lithosphere that is distinct from the mantle in terms of temperature and composition remains stable against convective erosion heat advection to different depth beneath the thin and the thick lithosphere leads to a maximum horizontal contrast of 500 c at 150 km depth over a lateral transition distance of 100 km sufficient to generate 5 and 8 in maximum p and s wave velocity perturbation respectively a purely conductive model under the same conditions yields only vp 1 and vs 2 while a lithospheric evolution simulation without a compositional effect on the rheology leads to significant thermo mechanical erosion of the lithosphere giving vp 2 and vs 4

sharp contrast in lithospheric structure across the sorgenfrei tornquist zone as inferred by rayleigh wave analysis of tor1 project data abstract this work is a part of the tor1 project 1996 1997 and is devoted to determining the lithospheric structure across the sorgenfrei tornquist zone in northern europe for the first time in europe a very dense seismic broadband array has offered the possibility of determining very sharp lateral variations in the structure of the lithosphere at small scales using surface wave analysis we measure phase velocities for rayleigh waves with periods ranging between 10 and 100 s both within arrays with apertures of 40 50 km small compared to the wavelength and along long profiles of at least 100 km dispersion curves are then inverted and shear wave velocity models down to the depth of 200 km are proposed we show that the sorgenfrei tornquist zone is a major tectonic feature within the whole lithosphere north east of this feature in sweden beneath the baltic shield no lithosphere asthenosphere boundary is observed to exist to depths of 200 km south west of the sorgenfrei tornquist zone beneath denmark we find a lithospheric thickness of 120 20 km the transition across the sorgenfrei tornquist zone is sharp and determined to be very steeply dipping to the south west we also demonstrate the existence of a sharp discontinuity between the lithospheres beneath denmark 120 20 km thick and beneath germany characterized by thicknesses of 50 10 km in the northernmost part and 100 20 km in the southwest this discontinuity is most likely related to the trans european fault at the surface

deep seismic investigation of crustal extensional structures in the danish basin along the estrid 2 profile summary the crust and uppermost mantle in the danish basin are investigated by modelling the p wave velocity distribution along the north south trending seismic profile estrid 2 seismic tomography and ray inversion modelling demonstrate a variable depth to the top of the crystalline crust from 10 km in the northern part of the profile to 2 km depth in the southernmost part the crystalline crust shows very high p wave velocity in the central part of the profile with 6 7 km s 1 at depths as shallow as 12 km and 7 3 7 5 km s 1 in the lowermost crust these values confirm previous results obtained along the orthogonal estrid 1 profile and the eugeno s profile 2 this high velocity zone in the middle to lower crust is interpreted as a mafic intrusion which explains a positive gravity anomaly of 50 mgal silkeborg gravity high the total length of the intrusion is at least 80 km in the east west direction and 25 35 km in the north south direction the estimated thickness of the intrusion from its top to the moho level is 18 20 km which gives a total minimum volume of 40 50 000 km3 the reflectivity properties of the moho discontinuity are variable along the profile below the intrusion the pmp signal is very weak due to the small velocity contrast between the lowermost crust 7 4 km s 1 and uppermost mantle 7 6 7 7 km s 1 the main moho reflection has a reverberative character to the south of the intrusion this feature is interpreted by layering at the moho level possibly due to magmatic underplating the occurrence of a large crustal mafic intrusion associated with magmatic underplating may be related to extensional transtensional tectonism in the tornquist fan area in the late palaeozoic the extensional event probably caused the opening of a plumbing system for intrusion of mantle derived magma into the crust the ascending magma may have been injected at upper middle crustal levels and during the late phases of the development squeezed laterally along the moho

seismic evidence for widespread western us deep crustal deformation caused by extension morgan moschetti and colleagues use ambient noise tomography data from the western united states to show that strong radial seismic anisotropy exists in the deep crust confined mainly to the geological provinces that have undergone significant extension during the cenozoic era since about 65 million years ago the coincidence of crustal radial anisotropy with these extensional provinces supports the hypothesis that the deep crust within these regions has undergone widespread and relatively uniform strain in response to crustal thinning and extension here a method of seismic wave imaging known as ambient noise tomography is used to generate high resolution images of seismic wave speeds in the crust and uppermost mantle the observations reveal strong and uniform anisotropy where waves travel through rock at different speeds depending on direction in the deep crust in areas of the western united states that have undergone significant extension during the past 65 million years laboratory experiments have established that many of the materials comprising the earth are strongly anisotropic in terms of seismic wave speeds1 observations of azimuthal2 3 and radial4 5 anisotropy in the upper mantle are attributed to the lattice preferred orientation of olivine caused by the shear strains associated with deformation and provide some of the most direct evidence for deformation and flow within the earth s interior although observations of crustal radial anisotropy would improve our understanding of crustal deformation and flow patterns resulting from tectonic processes large scale observations have been limited to regions of particularly thick crust6 here we show that observations from ambient noise tomography in the western united states reveal strong deep middle to lower crustal radial anisotropy that is confined mainly to the geological provinces that have undergone significant extension during the cenozoic era since 65 myr ago 7 8 the coincidence of crustal radial anisotropy with the extensional provinces of the western united states suggests that the radial anisotropy results from the lattice preferred orientation of anisotropic crustal minerals caused by extensional deformation these observations also provide support for the hypothesis that the deep crust within these regions has undergone widespread and relatively uniform strain in response to crustal thinning and extension9 10 11