nonlinear soil site effects in probabilistic seismic hazard analysis this study presents effective probabilistic procedures for evaluating ground motion hazard at the free field surface of a nonlinear soil deposit located at a specific site ground motion at the surface or at any depth of interest within the soil formation e g at the structure foundation level is defined here in terms either of a suite of oscillator frequency dependent hazard curves for spectral acceleration or of one or more spectral acceleration uniform hazard spectra each associated s s f a with a given mean return period it is presumed that similar information is available for the rock outcrop input the effects of uncertainty in soil properties are directly included this methodology incorporates the amplification of the local soil deposit into the framework of probabilistic seismic hazard analysis psha the soil amplification is characterized by a frequency dependent amplification function af f where f is a generic oscillator frequency af f is defined as the ratio of to the spectral s s f a acceleration at the bedrock level the estimates of the statistics of the ampli s s f a fication function are obtained by a limited number of nonlinear dynamic analyses of the soil column with uncertain properties as discussed in a companion article in this issue bazzurro and cornell 2004 the hazard at the soil surface or at any desired depth is computed by convolving the site specific hazard curve at the bedrock level with the probability distribution of the amplification function the approach presented here provides more precise surface ground motion hazard estimates than those found by means of standard attenuation laws for generic soil conditions the use of generic ground motion predictive equations may in fact lead to inaccurate results especially for soft clay soil sites where considerable amplifi cation is expected at long periods and for saturated sandy sites where high intensity ground shaking may cause loss of shear strength owing to liquefaction or to cyclic mobility both such cases are considered in this article in addition to the proposed procedure two alternative easier to implement but approximate techniques for obtaining hazard estimates at the soil surface are also briefly discussed one is based on running a conventional psha with a rock attenuation relationship modified to include the soil response whereas the other consists of using a simple analytical closed form solution that appropriately mod ifies the hazard results at the rock level

sedimentology stratigraphy and geochronology of the proterozoic mazatzal group central arizona quartzite conglomerate and shale of the mazatzal group record the filling of a prot erozoic intra arc basin in central arizona u pb ages of zircons from rhyolite ash flow tuff indicate that deposition began at 1701 2 ma basal deposits of the newly defined pine creek conglomerate formed in an alluvial fan setting synchronous with the final phase of extrusive rhyolite volcanism and active faulting after volcanic activity ceased shallower slope braided stream environments developed in early deadman quartzite time subsequent marine transgression produced shallow subaqueous deposits of the upper part of the deadman quartzite these were overlain by prodelta sediments of the maverick shale indicating a phase of basin deepening finally the mazatzal peak quartzite was deposited as the basin shoaled again first to shallow marine and subsequently to fluvial conditions the quartzite is diagenetic quartz arenite originally deposited as lithic arenite and lithic arkose the provenance was initially restricted and earliest sediment was derived mainly from the subjacent red rock group when tectonic activity ceased how ever the surrounding highlands were planed down by erosion and detritus from a wider variety of source rocks was funneled into the basin this included contributions from arc related supracrustal rocks of the payson ophiolite and east verde river formation and finally a granitic basement input detrital quartz in the lower part of the mazatzal group is largely monocrystalline and volcanic in origin polycrystalline quartz associated with detrital feldspar and of probable continental affinity is concentrated in the uppermost parts of the sequence the life span of the intra arc basin was on the order of 30 m y from the formation of the payson ophiolite at 1 73 ga to the deposition of the upper mazatzal peak quartzite sometime after 1 70 ga the pre mazatzal red rock group represents the last stages of volcanic arc activity and the mazatzal group records the transition from orogenic to nonorogenic sedimentation in central arizona

diagenetic origin for quartz pebble conglomerates the occurrence of quartz pebble conglomerates qpc in the rock record increases backward through time from the tertiary through the precambrian the positive correlation between qpc abundance and age is valid both for numbers of reported qpc and for qpc as a percentage of all conglomerate and at both the era and the period level qpc are usually interpreted as being due to intense chemical weathering protracted transport or sediment recycling but none of these can account for the age distribution of qpc which is the opposite of the global mass age distribution for sedimentary rocks precambrian and tertiary conglomerates with similar sources and sedimentology have vastly different clast populations nonquartzose clasts being much more abundant in the younger rocks comparison of the petrology of qpc and polymict conglomerates shows that qpc have consistently higher proportions of diagenetic secondary matrix and pressure solved grain contacts we conclude that diagenetic factors play an important role in qpc formation by preferentially destroying less durable clasts

incorporating results from seismic microzonation into probabilistic seismic hazard analysis an example in western liguria italy abstract this study presents a first attempt to couple two of the most important components of seismic risk mitigation strategies probabilistic seismic hazard analysis psha and seismic microzonation we show an application in the westernmost sector of the liguria region in northwestern italy an area where strong earthquakes up to about magnitude 6 5 occurred in the past producing hundreds of casualties the final goal is to produce probabilistic seismic hazard maps for peak ground acceleration and spectral acceleration that incorporate site amplification by amending existing ground motion attenuation models for rock conditions with an additional amplification term provided by microzonation studies on a municipal scale to this end a partially non ergodic approach is applied according to modern practice compared to conventional ergodic hazard assessments for rock conditions and flat topography such maps provide at a glance a finer picture of the actual hazard of the area under study highlighting those sites where the ground motion hazard is dominated by local amplification effects at these sites the expected ground motions are up to twice the values resulting from the traditional ergodic psha on rock besides hazard maps results are also presented in terms of uniform hazard spectra for a number of target sites comparison with the isoseismal maps of past earthquakes have revealed a good agreement between the spatial distribution of the assessed hazard and that of felt intensities with greater damage observed in areas presenting significant amplification effects and consequently a higher seismic hazard

seismic hazard assessment 2003 2009 for the italian building code this paper describes the probabilistic assessment of seismic hazard psha of italy in view of the building codes from 2003 to 2009 a code was issued in 2003 as a prime minister ordinance requiring that a psha for updating the seismic zoning would be performed in one year in terms of horizontal peak ground acceleration pga with 10 probability of exceedance in 50 years on hard ground for the first time in italy a working group established by the istituto nazionale di geofisica e vulcanologia adopted a logic tree approach to model the epistemic uncertainty in the completeness of the earthquake catalog the assessment of the seismicity rates and m max and the ground motion prediction equations the seismic hazard has been computed over a grid of more than 16 000 points for the median value fiftieth percentile and the eighty fourth and sixteenth percentiles of the 16 branches of the logic tree using the same input model pga values and spectral accelerations for 10 spectral periods were computed for nine different probabilities of exceedance in 50 years this wealth of data made it possible to base the design spectra of a new building code on point hazard data instead of being related to just four zones the 2009 m w 6 3 l aquila earthquake has led many to attempt to test the reliability of this study in this paper we analyze suggestions coming from that event and conclude that significant changes to the design spectra are not to be recommended based just on evidence from the l aquila earthquake

relating cenozoic north sea sediments to topography in southern norway the interplay between tectonics and climate abstract about 482 000 km 3 of sediment ca 24 m ma accumulated in the north sea during the cenozoic early cenozoic sedimentation was likely due to uplift of the circum north atlantic landmasses related to continental break up kilometre scale transient uplift and in some areas permanent uplift generated sources for progradational influx of clastic sediments from scotland the shetland platform and to a lesser degree southwestern norway the eocene sedimentation pattern was similar to the palaeocene with lower rates of accumulation associated with flooding and tectonic quiescence sediment influx from the shetland platform continued throughout the cenozoic while supply from southern norway increased markedly around the eocene oligocene coeval with the greenhouse icehouse transition mass balance calculations of sediment and eroded rock volumes suggest that while some topography along the western margin of norway may be pre cenozoic significant uplift of the main paleic surface in southern norway occurred around the early oligocene sedimentation rates were almost ten fold higher than the cenozoic average in the plio pleistocene slightly higher than the global average mass balance calculations indicate that plio pleistocene erosion over deepened a pre existing topography

the 2012 ferrara seismic sequence regional crustal structure earthquake sources and seismic hazard 1 inadequate seismic design codes can be dangerous particularly when they underestimate the true hazard in this study we use data from a sequence of moderate sized earthquakes in northeast italy to validate and test a regional wave propagation model which in turn is used to understand some weaknesses of the current design spectra our velocity model while regionalized and somewhatad hoc is consistent with geophysical observations and the local geology in the 0 02 0 1 hz band this model is validated by using it to calculate moment tensor solutions of 20 earthquakes 5 6 mw 3 2 in the 2012 ferrara italy seismic sequence the seismic spectra observed for the relatively small main shock significantly exceeded the design spectra to be used in the area for critical structures observations and synthetics reveal that the ground motions are dominated by long duration surface waves which apparently the design codes do not adequately anticipate in light of our results the present seismic hazard assessment in the entire pianura padana including the city of milan needs to be re evaluated

disaggregation of probabilistic ground motion hazard in italy abstract probabilistic seismic hazard analysis is a process that integrates over aleatory uncertainties e g future earthquake locations and magnitudes to calculate the mean annual rate of exceedance mre of given ground motion parameter values at a site these rates reflect the contributions of all the sources whose seismic activity is deemed to affect the hazard at that site seismic hazard disaggregation provides insights into the earthquake scenarios driving the hazard at a given ground motion level this work presents the disaggregation at each grid point of the italian rock ground motion hazard maps developed by gruppo di lavoro mps 2004 meletti and montaldo 2007 and montaldo and meletti 2007 disaggregation is used here to compute the contributions to the mre of peak ground horizontal acceleration pga and 5 damped 0 2 1 0 and 2 0 sec spectral acceleration values corresponding to different mean return periods mrps of 475 and 2475 yr from different scenarios these scenarios are characterized by bins of magnitude m source to site distance r and number e of standard deviations that the ground motion parameter is away from its median value for that m r pair as estimated by a prediction equation maps showing the geographical distribution of the mean and modal values of m r and e are presented for the first time for all of italy complete joint m r e distributions are also presented for selected cities except for sites where the earthquake activity is characterized by sporadic low magnitude events the hazard is generally dominated by local seismicity moreover as expected the mre of long period spectral accelerations is generally controlled by large magnitude earthquakes at long distances while smaller events at shorter distances dominate the pga and short period spectral acceleration hazard finally for a given site as the mrp increases the dominant earthquakes tend to become larger and to occur closer to the site investigated

composition and discrimination of sandstones a statistical evaluation of different analytical methods the discriminative power of four analytical approaches to sandstone composition is evaluated with respect to the separation of different formations and source areas the case study is cretaceous synorogenic sandstones litharenites from the eastern alps of europe which belong to four different formations and are derived from two source areas methods evaluated are light mineral analysis petrographic framework composition heavy mineral analysis major element xrf analysis and trace element xrf analysis the statistical parameters calculated percentages of well classified samples mahalanobis distance applying the logratio approach suggest that light mineral analysis has a significantly lower discriminative power than the other three methods taking into account the analytical expenditure for data acquisition trace element analysis appears to be the most efficient method for discrimination of at least the sandstone units examined although based on a single case study these results are interpreted to have a more general meaning with respect to sandstone discrimination based on composition concerning sandstone provenance trace element analysis provides a quick tool to estimate the discriminative potential of a sample suite i e the potential to discriminate between contrasting source areas if a provenance model already exists and discriminate functions between contrasting source areas are calculated trace element analysis is considered to be most efficient in correctly assigning an unknown sample to its source area these results cannot be extended to all kinds of sands and sandstones but they cast serious doubt on the belief that petrographic point count methods are the best approach to discriminate between sandstones

estimation of q for long period 2 sec waves in the los angeles basin we simulate 0 to 0 5 hz 3d wave propagation through the southern california earthquake center seismic velocity reference model version 2 for the 1994 northridge earthquake in order to examine the effects of anelastic attenuation and amplification within the near surface sediments we use a fourth order finite difference staggered grid method with the coarse grained frequency independent anelastic scheme of day and bradley 2001 and a variable slip distribution from kinematic inversion for the northridge earthquake we find that the near surface material with s wave velocity v s as low as 500 m sec significantly affects the long period peak ground velocities compared with simulations in which the s wave velocity is constrained to 1 km sec and greater anelastic attenuation also has a strong effect on ground motion amplitudes reducing the predicted peak velocity by a factor of up to 2 5 relative to lossless simulations our preferred q model is q s v s 0 02 v s in meters per second for v s less than 1 2 km sec and much larger q s v s 0 1 v s in meters per second for layers with higher velocities the simple model reduces the standard deviation of the residuals between synthetic and observed natural log of peak velocity from 1 13 to 0 26 relative to simulations for the lossless case the anelastic losses have their largest effect on short period surface waves propagating in the los angeles basin which are principally sensitive to q s in the low velocity near surface sediments of the basin the low frequency ground motion simulated here is relatively insensitive to q p as well as to the values of q s at depths greater than roughly that of the 2 km sec s wave velocity isosurface

diagenetic history and provenance of devonian terrestrial sandstones at the margin of gondwana padeha formation eastern alborz iran abstract the northern margin of gondwana in iran rifted in the devonian forming a passive continental margin to the paleotethys ocean the details of which are obscured by later collision a record of the early phase of opening of paleotethys is preserved in the 600 m thick padeha formation a middle devonian terrestrial rift basin succession the sandstones are quartz arenite sub arkose and arkose and contain minimal detrital matrix 1 bulk rock geochemistry according to major elements suggests a source to the sandstones that was dominated by i type granite but also based on trace elements included small amounts of intermediate or mafic rocks low zr and hree contents suggest little or no sandstone in the source area and thus low abundance of fine grained heavy minerals

far source long period displacement response spectra in the po and venetian plains italy from 3d wavefield simulations abstract design elastic displacement spectra for seismic codes and zoning studies of seismic hazard for long period structures are becoming of utmost importance in modern earthquake engineering the increase of displacement based design approaches together with the availability of good quality digital strong motion data allow the creation of reliable spectral shapes for seismic design of up to 10 s nevertheless to characterize the site amplification effects during large levels of shaking additional studies are needed especially in deep sedimentary basins and plains that can be strongly excited by large amplitude long period waves data within deep basins is rare because accelerometric seismic networks are normally deployed on rock or stiff soil and modeling of waveforms is hence necessary for bridging this gap focusing on the numerical modeling of the 3d wavefield in 1d flat layered and 3d structures in the po and venetian plains northern italy and on earthquakes with magnitudes m 6 6 and hypocentral distances greater than 50 km in this study we 1 estimate the displacement response spectra drs from 1 to 10 s in the po and venetian plains 2 compare the drs from numerical simulations using flat layered and heterogeneous 3d models against the currently available uniform hazard drs for italy and 3 evaluate the influence of deep sediments on drs shape and thus on seismic codes finally 1d and 3d simulated drs are compared with drs obtained from recordings in the kanto basin where similar long period displacement is observed

digital terrain modelling a review of hydrological geomorphological and biological applications the topography of a catchment has a major impact on the hydrological geomorphological and biological processes active in the landscape the spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques many geographic information systems are being developed that store topographic information as the primary data for analysing water resource and biological problems furthermore topography can be used to develop more physically realistic structures for hydrologic and water quality models that directly account for the impact of topography on the hydrology digital elevation models are the primary data used in the analysis of catchment topography we describe elevation data sources digital elevation model structures and the analysis of digital elevation data for hydrological geomorphological and biological applications some hydrologic models that make use of digital representations of topography are also considered

the sediment delivery problem abstract the linking of on site rates of erosion and soil loss within a drainage basin to the sediment yield at the basin outlet and improved knowledge and representation of the associated processes of sediment delivery represent a major research need within the field of erosion and sedimentation and also an important scale problem in drainage basin studies this paper reviews the limitations of the sediment delivery ratio concept by considering the problems of temporal and spatial lumping and its blackbox nature some recent advances in our understanding of the sediment delivery system and its modelling are described and the lack of detailed empirical investigations is highlighted the significance of recent concern for the role of sediments in the transport of nutrients and contaminants to sediment delivery studies is introduced and the need for further work in this field is emphasised

geochemical identification of clastic sediment provenance from known sources of similar geology the cretaceous scotian basin canada abstract this study tests the effectiveness of a geochemical approach in identifying provenance in a basin where different sources do not show strongly contrasting geology petrological studies indicate that at least three distinct rivers draining reactivated horsts of the appalachian orogen supplied sediment to the lower cretaceous deltaic sandstones and mudrocks in the offshore scotian basin ninety five samples mostly from conventional core were analyzed for 44 major and trace elements the data were first screened for variability unrelated to provenance including changes in elemental abundance due to weathering and diagenesis and the effects of grain size and sorting on element variation the effect of hydraulic sorting was distinguished from the effects of concentration of ultrastable heavy minerals from polycyclic sources multivariate statistical analysis by principal component analysis pca was used to test the hypothesis of three discrete sources suggested by the petrologic model major element pca on sandstones discriminated the sources but results from trace element pca required further investigation using element biplots to understand their significance only a few elements were found to be diagnostic of different sources namely k rb sr u th nb and ti with the latter two of value only for sandstones all of these are elements that are abundant in the granites of the appalachians most published geochemical discrimination diagrams did a poor job of distinguishing the three petrographically recognized sources in other basins with quite different hinterland geology other elements are known to be of value in discriminating provenance thus it is unlikely that a globally applicable set of elemental discriminants can identify terrigenous sediment sources rather systematic investigation is needed that evaluates processes such as diagenesis and sorting and then tests geographic and stratigraphic variability in bulk geochemistry informed by at least semiquantitative petrographic data

provenance of the triassic songpan ganzi flysch west china abstract the songpan ganzi basin of western china is a triangular structure on the northeast corner of the qinghai tibet plateau filled with a great thickness of triassic flysch surrounded to the north by the eastern kunlun orogenic belt that extends farther eastwards as the qinling dabie belt to the southwest by the ganzi litang ophiolite and yidun volcanic arc and to the east by the longmenshan thrust belt we have carried out the most extensive petrographic and geochemical study so far undertaken on typical turbidites from the songpan ganzi basin including major element trace element rb sr and sm nd isotopic analyses in the baryan har region on the northern side of the basin petrographic study identifies the sandstones as typical graywackes whose matrix is fine grained detrital material recrystallized by greenschist facies metamorphism chemical weathering indices confirm that the fine grained turbidites were little altered during transport and deposition so compositions accurately represent their source areas major trace and isotope analyses displayed on various discriminant diagrams indicate that the flysch from the baryan har region is derived from the eastern kunlun belt to the north a conclusion supported by published paleocurrent directions comparison of the baryan har turbidites with published results from western sichuan on the eastern side of the songpan ganzi basin suggests that the latter is derived from a source area of varied sedimentary rocks and a few igneous rocks the most likely source is south qinling to the northeast presently available data do not support derivation of material in the songpan ganzi basin from the yidun volcanic arc or the dabie ultra high pressure metamorphic belt the present provenance studies on the triassic songpan ganzi flysch support a westward opening model for the paleotethyan ocean and reveal different evolutional histories for the qilian qinling dabie and eastern kunlun orogens

mapping soil erosion hotspots and assessing the potential impacts of land management practices in the highlands of ethiopia abstract an enormous effort is underway in ethiopia to address soil erosion and restore overall land productivity modelling and participatory approaches can be used to delineate erosion hotspots plan site and context specific interventions and assess their impacts in this study we employed a modelling interface developed based on the revised universal soil loss equation adjusted by the sediment delivery ratio to map the spatial distribution of net soil loss and identify priority areas of intervention using the modelling interface we also simulated the potential impacts of different soil and water conservation measures in reducing net soil loss model predictions showed that net soil loss in the study area ranges between 0 4 and 88 t ha 1 yr 1 with an average of 12 t ha 1 yr 1 the dominant soil erosion hotspots were associated with steep slopes gullies communal grazing and cultivated areas the average soil loss observed in this study is higher than the tolerable soil loss rate estimated for the highland of ethiopia the scenario analysis results showed that targeting hotspot areas where soil loss exceeds 10 t ha 1 yr 1 could reduce net soil loss to the tolerable limit

an experimental approach for estimating seismic amplification effects at the top of a ridge and the implication for ground motion predictions the case of narni central italy abstract from march to september 2009 a velocimetric network was installed in narni central italy a village on the top of a limestone ridge the aim was to investigate local site effects due to the 220 m high ridge which is characterized by slopes ranging from 22 to 35 to investigate amplification without and with a reference site three stations were installed at the base of the hill and seven at the crest the network recorded 702 earthquakes many of them from the 2009 l aquila sequence to determine the dependence of amplification on the morphological features the spectra were computed for horizontal components rotated into a range of azimuths both the ratio of the horizontal to vertical component spectra and the ratio of the spectra at the ridge crest with respect to a reference station at the base of the ridge showed amplification by a factor of circa 4 5 for frequencies between 4 hz and 5 hz the highest amplifications were seen for the directions of the ground motion perpendicular to the main elongation of the ridge finally considering events with an epicentral distance less than 30 km empirical ground motion models were calibrated for maximum horizontal peak ground acceleration pga velocity and acceleration response spectra 5 damping up to 1 s to estimate the site corrective coefficients for topographic amplification the data show corrective coefficients between 0 35 and 0 48 log 10 scale amplification 2 2 3 0 for the spectral ordinates between 0 2 s and 0 3 s

subsurface magnetostratigraphy of pleistocene sediments from the po plain italy constraints on rates of sedimentation and rock uplift we used facies analysis to reconstruct the pleistocene sedimentary evolution of seven cores from the central northern po plain italy the cores record an overall regressive sequence consisting of shallow water marine and fl uvial deltaic deposits overlain by fully continental sediments we used magnetostratigraphy to date marine and fl uvial deltaic sediments to the early pleistocene and continental sediments to the middle late pleistocene sediment accumulation rates were 30 40 cm k y in the early pleistocene whereas relevant unconformities and or an overall reduction in sediment accumulation rates characterized the middle late pleistocene a simple airy compensation model was applied to restore actual sediments elevations to elevations at times of deposition expressed in meters above current sea level the correlation of isostatically corrected sedimentary facies to a sea level curve obtained from classic oxygen isotope studies shows that an event of rock uplift on the order of 70 120 m occurred in the middle late pleistocene literature studies of vegetational cyclicity used in conjunction with the sea level curve allowed us to link sedimentary facies to climate variability we propose that the onset of fully and persistently continental sedimentation occurred in response to the waxing of the fi rst major pleistocene glaciation in the alps currently correlated to marine isotope stage 22 at ca 0 87 ma and that the episode of uplift occurred at least in part as a consequence of erosion and crustal rebound of the alpine chain triggered by pleistocene glacialinterglacial cycles

thermochronological evidence for a late pliocene climate induced erosion rate increase in the alps u th he and fission track analyses of apatite along deep seated tunnels crossing high relief mountain ranges offer the opportunity to investigate climate tectonic forcing on topographic evolution in this study the thermochronologic analysis along the simplon tunnel western central alps italy and switzerland constrains in detail the mechanisms controlling the topographic evolution of the simplon massif cooling rates vary from about 10 c ma at about 10 ma to about 35 c ma in the last 3 ma such increase in cooling rates corresponds to the inception of glacial cycles in the northern hemisphere age patterns show correlation with faults distribution until 2 ma suggesting that tectonics controlled rocks exhumed up to that age after 2 ma thermo chronometric data show that the simplon area has experienced primarily erosional exhumation all age patterns provided are not affected by topographic effects thus indicating that present day topography has been carved in the last 2 ma most likely controlled by glacial erosion

geochemistry of sandstones from the upper miocene kudankulam formation southern india implications for provenance weathering and tectonic setting abstract petrographic major trace and rare earth element compositions of sandstones from the upper miocene kudankulam formation southern india have been investigated to determine their provenance tectonic setting and weathering conditions all sandstone samples are highly enriched in quartz q but poor in feldspar f and lithic fragments l the major element concentrations of these sandstones reveal the relative homogeneity of their source geochemically the kudankulam sandstones are classified as arkose subarkose litharenite and sublitharenite the cia values chemical index of alteration mean value 44 5 for these sandstones and the a cn k diagram suggest their low weathering nature similarly their fe2o3 mgo mean 2 7 al2o3 sio2 0 09 k2o na2o 2 2 ratios and tio2 contents 0 3 are consistent with a passive margin setting the eu eu 0 5 la lu cn 21 la sc 5 9 th sc 1 9 la co 5 7 th co 1 8 and cr th 5 3 ratios support a felsic source for these sandstones chondrite normalized ree patterns with lree enrichment flat hree and negative eu anomaly also are attributed to felsic source rock characteristics for kudankulam sandstones total ree concentrations of these sandstones reflect the variations in their grain size fractions the source rocks are probably identified to be proterozoic gneisses charnockites and granites of the kerala khondalite belt which must have been exposed at least since the late miocene finally the unusual ni enrichment in the kudankulam sandstones unaccompanied by a similar enrichment in cr co and v may be related to either the presence of pyrite in the sandstones or more likely the fractionation of garnet from the source rocks during transportation

sediment export by water from an agricultural catchment in the loam belt of central belgium abstract an agricultural drainage basin of 250 ha was selected in the belgian loam belt to evaluate sediment export by water water discharge was continuously measured at the outlet of the catchment and suspended sediment samples were taken proportional with discharge during rainfall events from these samples supended sediment concentration and grain size distribution were determined within the catchment regular surveys were conducted in order to obtain detailed data on vegetation cover soil surface parameters and erosion and sedimentation features important variations in sediment yield were detected at various time scales ranging from a year over a season to one event these variations could be linked with processes occurring within the catchment due to the development of a vegetation cover the suspended sediment concentrations were lower during the summer period than during the winter period for the same discharge the evolution in both suspended sediment concentration and grain size distribution during the winter period is explained by variations in the soil surface state of the fields as well as the development of a rill and gully network the positive hysteresis observed within a single event is explained by taking into account the distance between the sediment source and the catchment outlet and not by sediment flushing our analysis shows that the role of the main factors controlling the geomorphic response of such a catchment can be identified only if measurements at the outlet are complemented by detailed data on the conditions within the catchment catchment model calibration and validation are therefore impossible if this information is lacking

methodology for estimating the topographic factor ls of rusle3d and usped using gis abstract in the rusle3d revised universal soil loss equation 3d and usped unit stream power based erosion deposition models the effects of topography on soil loss are represented by the combined factor ls where l is the slope length factor and s the slope gradient factor the problems with measuring slope gradient and length over large areas are i they are not always estimated correctly and ii different ways are used for their calculation gis geographical information systems software has several algorithms for estimating topographic parameters included in the equations of ls the objective of this research was developing a methodology for ls calculation using gis in order to define the most accurate algorithm for each parameter for the estimation of s and upslope contribution area l the zevenbergen and thorne algorithm and the deterministic infinity algorithm respectively were selected

inorganic geochemistry of the type caradoc series sandbian to middle katian upper ordovician onny valley shropshire uk the geochemistry and petrology of the type section of the caradoc series in the onny valley indicate that it was deposited on a marginal basin continental shelf similar to the western side of the present sea of japan the lower beds form a transgressive regressive sequence in which the rocks become less mature upwards all the coarser sediments above the basal quartzites and conglomerates are greywackes in which the apparent muddy and ferrous matrix is due to the breakdown of unstable minerals and particles higher values of na 2 o and na k ratios are found in the coarser shallow water sandstones of the horderley sandstone formation and decrease markedly in the succeeding beds accompanied by an increase in k 2 o higher values of carbonate corrected and hence related other major and minor elements like sio 2 cao p 2 o 5 mno and most trace elements correlate with the transgressive systems and maximum flooding surfaces of the three sequences recognized where they are related to condensation at those horizons chemical indices of alteration cia suggest that the horderley sandstone formation underwent greater predepositional physical weathering than lower and higher beds which is compatible with the petrography and were deposited during a cool phase within overall warm sandbian katian times trace element ratios suggest an oxic to suboxic depositional environment

geochemical correlation between metasediments of the mfongosi group of the natal sector of the namaqua natal metamorphic province south africa and the ahlmannryggen group of the grunehogna province antarctica abstract the whole rock geochemistry of metamorphosed greywackes arenites and arkoses within the mesoproterozoic namaqua natal maudheim province is interpreted with the aim of establishing geochemical correlations and defining common sediment source terrains metasediments of the mfongosi group of the natal sector of the namaqua natal metamorphic province were sampled from their type area in the mfongosi valley metagreywackes from the northern limits of the mfongosi valley directly adjacent to the kaapvaal craton show ocean island arc signatures while metagreywackes from the southern limits of the mfongosi valley near the contact with the madidima thrust of the natal nappe zone show mainly active continental margin signatures interleaved geochemically distinct low ca na high k metamorphosed arkoses to lithic arkoses indicate a minor passive margin sediment component geochemical classification of low grade ahlmannryggen group greywackes arenites and arkoses of the grunehogna province antarctica indicates both active and passive continental margin sediment sources an oceanic island arc signature is not evident in ahlmannryggen group data the active continental margin signature in both natal sector and grunehogna province metasediments potentially provides for a common link between these terranes discriminant function analysis using three pre defined provenance sub sets within the mfongosi group and two pre defined provenance sub sets within the ahlmannryggen group indicate that metasediments with active continental margin signatures from both groups are geochemically identical implying that the active continental margin of the grunehogna province shed immature sediments westwards african azimuths into the developing narrow or restricted mesoproterozoic mfongosi basin this was accompanied by minor sediment influx from a stable continental platform potentially the kaapvaal craton oblique and diachronous collision initiated in the southwestern portions of the combined natal sector grunehogna province system produced a laterally variable mfongosi group which formed in the mfongosi basin coarse grained sediments dominated in its eastern portions while basalts with thin sapropelite units dominated in its western portions

evaluation of probabilistic site specific seismic hazard methods and associated uncertainties with applications in the po plain northern italy site specific ground motion hazard as assessed by a probabilistic seismic hazard analysis one step approach that handles a single site sigma and its uncertainties and uses a simple logic tree is compared with a two step approach that includes bedrock motion evaluation and wave propagation through a local soil profile with consideration of the main epistemic uncertainties the one step analysis relies on accelerometer data from the po plain a sedimentary basin in northern italy where an earthquake sequence with two m w 6 0 events was extensively recorded in 2012 uniform hazard spectra uhs on soil and exposed bedrock are evaluated at three deep soil accelerometer sites mrn nvl and t0821 using residual measures available from other studies by which uncertainties in site terms s 2 s and single site sigma ss s are estimated despite similarity in geologic conditions at least one out of three sites in the one step analysis displays substantial differences in mean level t0821 or in the 84 16 percentile spread nvl depending on differences in site terms and single site sigma possibly caused by source to site propagation effects the two step approach was applied to the remaining site mrn using carefully selected and broadband matched acceleration signals and linear equivalent linear and nonlinear approaches as excitation in propagation analyses we found that assumptions on soil degradation curves dominate the variability of results the linear approach provided the best results based on 1 the similarity of the one step nonergodic uhs with the two step result based on the linear approach 2 the comparison with observed records at mrn during the 2012 sequence mainshocks showing peak ground acceleration and short period spectral levels well beyond those predicted by different nonlinear assumptions and 3 similar evidence from a set of 21 stations at deep soil sites of the japanese kik net

long period amplification in deep alluvial basins and consequences for site specific probabilistic seismic hazard analysis an example from the po plain northern italy this study deals with the impact of deep soil discontinuities on ground motion amplification in the po alluvial basin northern italy and consequently on long period probabilistic seismic hazard analysis estimates the focus is on castelleone where a seismic station of the italian national seismic network has been deployed since 2009 to define a detailed shear wave velocity v s profile extensive active and passive geophysical surveys were carried out the active measurements included seismic profiles examined through standard refraction techniques and multichannel analysis of surface waves the passive methods included ambient vibration measurements in both single and array configurations in particular three microtremor arrays with increasing apertures were performed to capture the experimental dispersion curve down to 0 2 hz the horizontal to vertical spectral ratio hvsr showed two main peaks at 0 17 and 0 70 hz a joint inversion of the experimental phase velocity dispersion and hvsr curves was performed to obtain the v s profile the data show two main discontinuities at 160 and 1350 m in depth according to the italian and european seismic codes the shallow v s discontinuity can be ascribed to the seismic bedrock i e v s 800 m s whereas the deeper one is observed at the transition between pliocene quaternary deposits and miocene marls preliminary site specific seismic hazard analysis in terms of displacement response spectra for periods up to 10 s shows that neglecting the effects of the deeper discontinuity implies underestimation in hazard estimates of up to about 49 for mean return period mrp of 475 years and about 57 for mrp of 2475 years with possible consequences regarding the design of very tall buildings and large bridges

packstones and floatstones ambiguous textures and origins in need of critical appraisal abstract the depositional textural classification of allochthonous limestones by dunham 1962 and its modifications by embry iii and klovan 1971 are widely used by carbonate petrologists during petrographic field studies and core examinations the origin and textures of packstones and floatstones used in this classification scheme need re appraisal towards their unified and unequivocal usage by carbonate petrologists in academia and the petroleum industry such usage will help avoiding inadequate interpretations of the depositional sequence stratigraphic or reservoir quality distribution models based on examination of jurassic cretaceous and holocene carbonate deposits from united arab emirates and oman it is suggested here that packstones should not be used to interpret energy of depositional environments because the majority are originally deposited as grainstones i e free of mud matrix thus sand and mud sized particles are expected to be hydraulically separated i e not deposited simultaneously therefore packstones might be originally grainstones that have incorporated variable amounts of mud matrix by various post depositional processes primarily bioturbation and or compaction deformation of peloids known as pseudomatrix dickinson 1970 we further observed that the 2 mm allochems in floatstones float in grainstones and packstones and not in mud wackestone matrix

strong motion from surface waves in deep sedimentary basins it is widely recognized that long period surface waves generated by conversion of body waves at the boundaries of deep sedimentary basins make an important contribution to strong ground motion the factors controlling the amplitude of such motion however are not widely understood a study of pseudovelocity response spectra of strong motion records from the los angeles basin shows that late arriving surface waves with group velocities of about 1 km sec dominate the ground motion for periods of 3 sec and longer the rate of amplitude decay for these waves is less than for the body waves and depends significantly on period with smaller decay for longer periods the amplitude can be modeled by the equation batchmode documentclass fleqn 10pt legalpaper article usepackage amssymb usepackage amsfonts usepackage amsmath pagestyle empty begin document mathrm log y f mathbf m r mathrm e c br mathrm b end document where y is the pseudovelocity response f m r e is an attenuation relation based on a general strong motion data set m is moment magnitude r e is the distance from the source to the edge of the basin r b is the distance from the edge of the basin to the recording site and b and c are parameters fit to the data the equation gives values larger by as much as a factor of 3 than given by the attenuation relationships based on general strong motion data sets for the same source site distance it is clear that surface waves need to be taken into account in the design of long period structures in deep sedimentary basins the ground motion levels specified by the earthquake provisions of current building codes in california at least accommodate the long period ground motions from basin edge generated surface waves for periods of 5 sec and less and earthquakes with moment magnitudes of 7 5 or less located more than 20 km outside the basin there may be problems at longer periods and for earthquakes located closer to the basin edge the results of this study suggest that anelastic attenuation may need to be included in attempts to model long period motion in deep sedimentary basins to obtain better data on surface waves in the future operators of strong motion networks should take special care for the faithful recording of the long period components of ground motion it will also be necessary to insure that at least some selected recorders once triggered continue to operate for a time sufficient for the surface waves to traverse the basin with velocities of about 1 km sec that time will be as long as 100 sec for a basin the size of the los angeles basin

present day geodynamics in the bend of the western and central alps as constrained by earthquake analysis summary the contrasted tectonics of the western central alps is examined using a synthesis of 389 reliable focal mechanisms the present day strain regime is mapped and interpolated for the entire alpine belt based on a newly developed method of regionalization the most striking feature is a continuous area of extension which closely follows the large scale topographic crest line of the alpine arc thrusting is observed locally limited to areas near the border of the alpine chain a majority of earthquakes within the alps and its forelands are in strike slip mode stress inversion methods have been applied to homogenous subsets of focal plane mechanisms in order to map regional variations in stress orientation the stress state is confirmed to be orogen perpendicular both for 3 in the inner extensional zones and 1 in the outer transcurrent transpressional zones extensional areas are well correlated with the part of the belt which presents the thickest crust as shown by the comparison with the bouguer anomaly and the average topography of the belt in the northwestern swiss alps extension is also correlated with currently uplifting zones these observations and our strain stress analyses support a geodynamic model for the western alps in which the current activity is mostly a result of gravitational body forces earthquakes do not provide any direct evidence for ongoing convergence in the alpine system but a relationship with ongoing activity of complex block rotations of the apulian microplate cannot be ruled out

cosmogenic nuclide derived rates of diffusive and episodic erosion in the glacially sculpted upper rhone valley swiss alps denudation rates of small tributary valleys in the upper rhone valley of the swiss central alps vary by more than an order of magnitude within a very small distance tens of kilometers morphometric data indicate two distinct erosion processes operate in these steep mountain valleys we determined the rates of these processes using cosmogenic beryllium 10 10be in pooled soil and stream sediment samples denudation in deep glacially scoured valleys is characterized by rapid non uniform processes such as debris flows and rock falls in these steep valleys denudation rates are 760 2100 mm kyr 1 in those basins which show minimal previous glacial modification denudation rates are low with 60 560 mm kyr 1 the denudation rate in each basin represents a binary mixture between the rapid non uniform processes and soil creep the soil production rate measured with cosmogenic 10be in soil samples averages at 60 mm kyr 1 mixing calculations suggest that the debris flows and rock falls are occurring at rates up to 3000 7000 mm kyr 1 these very high rates occur in the absence of baselevel lowering since the tributaries drain into the rhone trunk stream up stream of a knickzone the flux weighted spatial average of denudation rates for the upper rhone valley is 1400 mm kyr 1 which is similar to rock uplift rates determined in this area from leveling the pace and location of erosion processes are determined by the oscillation between a glacial and a non glacial state preventing the landscape from reaching equilibrium copyright 2010 john wiley sons ltd

continental depositional systems of the quaternary of the po plain northern italy abstract the po plain is a molasse foredeep bounded by two mountain chains apennines and alps apenninic thrusting is still active whereas the alpine one ended by early pliocene times the continental deposits form a veneer at the surface and form the topset of a prograding complex the po river divides the plain into two sectors with different sedimentary facies and body geometries to the south the alluvial fan and plain deposits are small embedded in clays and show elongate shapes to the north sedimentary bodies are laterally extensive tabular and with minor amounts of fine grained sediments this difference could be due to a different climatic conditions during quaternary ice ages on the two sides of the basin b different structural settings in the two sectors of the basin that produce a higher subsidence rate to the south c different lithologies in the source areas i e alps and apennines

soil and water losses from new citrus orchards growing on sloped soils in the western mediterranean basin ten representative research sites were selected in eastern spain to assess soil erosion rates and processes in new citrus orchards on sloping soils the experimental plots were located at representatives sites on limestone in areas with 498 to 715 mm year 1 mean annual rainfall north facing slopes herbicide treated and new less than 3 years old plantations ten rainfall simulation experiments 1 h at 55 mm h 1 on 0 25 m2 plots were carried out at each of the 10 selected study sites to determine the interill soil erosion and runoff rates the 100 rainfall simulation tests 10 10 m showed that ponding and runoff occurred in all the plots and quickly 121 and 195 s respectively following rainfall initiation runoff discharge was one third of the rainfall and sediment concentration reached 10 4 g l 1 the soil erosion rates were 2 4 mg ha 1 h 1 under 5 year return period rainfall thunderstorms these are among the highest soil erosion rates measured in the western mediterranean basin similar to badland mine spoil and road embankment land surfaces the positive relationship between runoff discharge and sediment concentration r2 0 83 shows that the sediment availability is very high soil erosion rates on new citrus orchards growing on sloped soils are neither tolerable nor sustainable copyright 2009 john wiley sons ltd

two phase stratigraphic model of foreland basin sequences application of flexural models to nonmarine foreland basin evolution indicates that two different stratigraphic styles of basin fill may develop over time basin subsidence is most rapid during times of thrust load emplacement associated sedimentation is coarse grained immediately adjacent to the thrust front and grades rapidly into fine grained deposits that cover most of the basin the distal part of the basin may also contain deposits derived from streams that flow from beyond the basin toward the thrust belt subsequent removal of the thrust load by erosion and other processes results in flexural rebound of the thrust belt and adjacent foreland basin during this postorogenic phase of adjustment a regional unconformity develops in the proximal part of the foreland basin proximal deposits along with thrust derived sediment are redeposited in the distal foreland basin and beyond this two phase model of foreland sedimentation predicts that coarsening upward sequences in the proximal and distal parts of the basin have reciprocal significance the proximal sequence represents thrust belt advance whereas the distal sequence represents thrust belt cessation

geochemical and petrological evidence for subduction accretion processes in the archean eastern indian craton the composition of sandstones often provides key evidence about the tectonic weathering and transport processes operating on the surface at the time of deposition petrologic and geochemical analyses of little metamorphosed middle late archean sandstones from the eastern indian craton show that the sedimentary rocks were derived from dominantly 3 3 ga old amphibolites of the older metamorphic group omg and tonalites of the older metamorphic tonalite gneisses omtg the two oldest lithologic units of this craton chondrite normalized rare earth element ree patterns of the sandstones show a light ree enriched signature with la sm n varying from 5 2 to 6 7 with no eu anomaly while the heavy rees display flat patterns with gd lu n values of 0 9 1 6 primitive mantle normalized incompatible and compatible trace element plots of these sandstones demonstrate an overall similarity with global proterozoic archean sandstones including strong nb ta negative anomalies in an fsm nd vs ond 0 diagram the sandstones plot precisely between the regional amphibolites and tonalites we infer from the ree abundances and the fsm nd vs ond 0 plot that the sandstones represent a bimodal mechanical mixture of omg and omtg the low ce pb ratios of these rocks of 1 4 indicate a variably pb enriched archean crust and that the ce pb ratio acquired the continental crustal signature distinctly different from those of the bulk silicate earth and mantle values at least as early as mid archean strong nb ta depletion relative to the primitive mantle suggests the sandstones were derived from subduction related magmatic arc sources this latter suggestion is strongly supported by the low nb ta and high zr sm ratios of these sandstones identical to archean tonalite trondhjemites that require based on recent trace element partitioning results their protoliths to have formed by subduction melting of lowmagnesium amphibolites or metamorphosed hydrous basalts 1 2 the average nd model ages of the sandstones are greater than the sm nd crystallization ages of the omg and omtg at v3 3 ga the geochemical data presented here can be collectively interpreted to suggest the presence of subduction accretion processes operational in the midarchean eastern indian craton because the omg and omtg the source rocks of the sandstones formed in a subduction related arc setting the basement rocks upon which this arc was constructed must have been older this observation and the depleted mantle nd model ages tdm of the sandstones ranging from 3 6 to 4 0 ga strongly indicate the presence of continental crust in this eastern indian craton older than 3 3 ga and possibly as old as

repeatable site and path effects on the ground motion sigma based on empirical data from southern california and simulated waveforms from the cybershake platform in this study we use two sets of residuals of the response spectral values to identify the repeatable effects due to specific ray paths and sites that are generally included in the standard deviation of the ground motion prediction equations gmpes one empirical set of residuals from the abrahamson et al 2014 gmpe and one set derived from simulated waveforms of the cybershake platform comparisons of the residuals at an oscillator period of 3 s lower usable limit of the 3d cybershake simulations show similarities between the site effects estimated from the two datasets with a correlation coefficient of 0 63 but the path effects are not similar correlation coefficient 0 for more than half of the sites evaluated comparing the cybershake path effects for moderate m w 6 5 and large m w 8 earthquakes showed that in most cases path effects from large magnitude earthquakes can be approximated using path effects from smaller earthquakes that have the same closest point to a site attention should be used when very large magnitude m w 8 events are involved and the fault crosses the sites finally the method for performing a fully nonergodic site specific probabilistic seismic hazard analysis including source path and site terms is outlined

provenance of late palaeozoic metasediments of the patagonian proto pacific margin southernmost chile and argentina in this provenance study of late palaeozoic metasediments of the eastern andean metamorphic complex eamc along the south patagonian proto pacific margin of gondwana the palaeogeological setting of the continental margin in devonian carboniferous and permian times is reconstructed the study is based on detrital heavy mineral contents chemical compositions of tourmaline grains and whole rock element and nd sr isotopic compositions element and isotopic compositions reveal that devonian carboniferous metaturbidites deposited before the development of a late carboniferous permian magmatic arc along the margin were mainly fed from felsic recycled old continental rocks the last recycling phase involved erosion of metasediments that were exposed in patagonia feeder systems to the basin cut either through epidote rich or garnet rich metasediments in permian time eamc metaturbidites were deposited next to the evolving magmatic arc and were derived from felsic crustal rocks two provenance domains are recognised the metasediments of the northern one are chemically similar to those of the devonian carboniferous metasediments this domain was fed from the metasedimentary host rocks of the magmatic arc the southern domain probably was fed from the arc proper as indicated mainly by the dominance of metaplutonic lithic fragments abundant detrital biotite and the major element composition of the metasediments

on the role of stiff soil deposits on seismic ground shaking in western liguria italy evidences from past earthquakes and site response abstract in this work we analyze the macroseismic fields of the main historical earthquakes occurred in western liguria northwestern italy in order to identify possible relations between the isoseismal patterns and the local geological setting anomalies in the spatial distribution of macroseismic intensities are often attributed to site effects we observed that in the region of study such anomalies are mainly located in areas characterized by outcropping pliocene soil deposits mainly made up of stiff silty and marly clays to investigate the influence of such deposits on ground response both horizontal to vertical spectral ratio measurements and numerical site response analyses were carried out for all sites analyzed the spectral ratio curves show marked amplification peaks between 2 and 5 hz following such empirical evidence equivalent linear ground response analyses were performed in order to examine the relation between the measured resonance frequencies and the response of a set of soil columns presenting pliocene marly clayey deposits at their top to this end a database of geotechnical and geophysical properties including 50 reference soil profiles was compiled this database was used to define alternative numerical models considering three different ranges of thickness of the pliocene marly clayey deposits between 5 and 35 m 30 and 65 m 60 and 105 m results show marked amplification effects in the ranges 1 3 hz 2 5 hz and 3 10 hz depending on the thickness of the investigated soil deposits these frequency ranges are in agreement with those observed from the experimental measurements which are therefore proved adequately representative of the resonance frequencies of the pliocene marly clayey deposits therefore based on our findings such deposits can be considered an essential factor in producing the anomalies observed in the isoseismal patterns of the macroseismic fields of the historical earthquakes occurred in western liguria

petrography geochemistry and nd isotope systematics of metaconglomerates and matrix rich metasedimentary rocks implications for the provenance and tectonic setting of the labrador trough canada the new quebec orogen consists of a supracrustal belt that was reworked when the superior craton collided with the core zone terrane during the paleoproterozoic trans hudson orogeny within the new

stratigraphic evidence of a middle pleistocene climate driven flexural uplift in the alps 1 this interdisciplinary study on the subsurface stratigraphy of the po plain northern italy brings new evidence in support of a climate driven erosional unloading of the alps since the middle pleistocene a newly acquired high resolution seismic profile and a critical review of industrial seismic lines were integrated with sedimentologic observations on four magnetostratigraphically dated continental cores to reconstruct a three sequence evolution of the pleistocene clastic infill in the northern po basin during the first sequence ps1 1 4 0 87 ma characterized by sedimentation rates of 34 cm kyr outpacing regional subsidence meandering river systems prograded over the basin passing downstream to a cyclothemic shelfal succession the second sequence ps2 0 87 0 45 ma heralded by a regional unconformity r surface correlated to the onset of the major pleistocene glaciations was characterized by widespread continental sedimentation of generally distal braidplain the third sequence ps3 0 45 ma to present marked at the base by another regional unconformity y surface is characterized by proximal braided fluvial deposition under combined conditions of confinement erosion and bypass we interpret the ps3 sequence as deposited under the effects of a flexural uplift of the northern po plain during the middle pleistocene starting at 0 45 ma in response to the long term erosional unloading of the alps triggered by the waxing and waning of alpine glaciers since the late early pleistocene global cooling 0 9 ma according to our modeling erosion on a relatively limited area of the alpine mountain chain ranging from 1 3 to 1 7 mm yr in the axial sector to 0 1 0 3 mm yr at the margins has been able to trigger rock uplift over a wider area including the proximal peripheral basins

grain size control of mineralogy and geochemistry in modern river sediment new guinea collision papua new guinea the new guinea collision includes diverse sediment source areas associated with arc continent collision to the west of the solomon sea triple junction and with subduction of oceanic crust to the southeast and northeast of the triple junction twenty seven sediment suites each comprising up to seven gravel sand and mud samples from the same locality were analysed to determine mineralogical and geochemical variation with changing grain size this paper deals primarily with the mineralogical variation compositional variation from coarse to fine grained fractions is generally 50 of each variable s abundance with many variables showing greater than 100 variation in contrast variation due to analytical error is generally less than 10 between year variation generally ranges from 15 to 25 and downstream variation is generally less than 50 petrographic results indicate that sediment composition is fundamentally dependent on grain size the principal control on sediment composition is mechanical weathering of rock fragments and compositional sorting of the constituent mineral phases while the gazzi dickinson method for point counting sediment reduces modal variability and in most cases provides robust provenance discrimination it is unsuitable for discerning faint source rock signatures often revealed by grain size dependent compositional variation only the upper plate magmatic arc provenance signature is evident from recalculated modal and geochemical data and that signature does not reflect the modern upper plate magmatic arc detailed petrographic analysis of grain types as opposed to recalculated modal or geochemical data is required to elucidate both upper and lower plate provenances and discriminate between ancient and contemporary arc provenances

provenance of cretaceous synorogenic sandstones in the eastern alps constraints from framework petrography heavy mineral analysis and mineral chemistry abstract the detrital components of cretaceous sedimentary rocks in the northern calcareous alps reflect the early alpine geodynamic evolution of the austroalpine microplate two contrasting source areas are distinguished on the base of light and heavy mineral analysis the first source area is located at the southeastern margin of the austroalpine and is composed of palaeozoic sediments and metamorphic rocks mesozoic carbonate rocks and ultrabasic rocks derived from the suture zone of the vardar meliata ocean the second source area is located in the northwest in a lower austroalpine position near the transpressive plate margin that juxtaposes austroalpine and penninic units this source area comprises palaeozoic low grade metamorphic rocks including high pressure hp rocks late palaeozoic meta sediments mesozoic carbonate rocks and ultrabasic rocks from obducted slices of penninic oceanic crust chemical analyses of detrital white mica amphibole and garnet support the discrimination between the two source areas tourmaline chemistry calls for a significant amount of metasedimentary rocks in the source area granitoid rocks and high grade metamorphic rocks are rare blue amphibole phengite and chloritoid composition suggest the erosion of lower blueschist facies rocks in the northwestern source area we suggest a modified model of austroalpine valanginian to coniacian tectono sedimentary evolution which is based on 1 an onset of subduction of the penninic ocean no earlier than late cretaceous 2 deposition of the analyzed sedimentary rocks in piggyback basins and 3 a reconstruction of provenance as proposed in this study

grain size geochemistry and organic pollutants in modern fluvial deposits in eastern moravia czech republic modern fluvial deposits from both small and large rivers were studied at 14 monitoring sites over 2 years 4 successive sampling seasons in the area of eastern moravia czech republic grain size geochemistry content of persistent organic pollutants pahs pcbs hchs ddts hcbs and pecb and toc were examined with the aim to understand their mutual relations and seasonal variations in sediment character and pollutant content sand and silt fraction predominate and the clay content is relatively low differences in provenance for various river systems were recognised both regional and seasonal variations in terms of content of persistent organic pollutants were documented the content of toc and mud was shown to play an important role in the accumulation of chlorinated persistent organic pollutants pcbs hchs ddts and hcb

quantification of the effects of secondary matrix on the analysis of sandstone composition and a petrographic chemical technique for retrieving original framework grain modes of altered sandstones abstract most studies of sandstone provenance involve modal analysis of framework grains using techniques that exclude the fine grained breakdown products of labile mineral grains and rock fragments usually termed secondary matrix or pseudomatrix however the data presented here demonstrate that when the proportion of pseudomatrix in a sandstone exceeds 10 standard petrographic analysis can lead to incorrect provenance interpretation petrographic schemes for provenance analysis such as qfl and qfr should not therefore be applied to sandstones containing more than 10 secondary matrix pseudomatrix is commonly abundant in sandstones and this is therefore a problem for provenance analysis the difficulty can be alleviated by the use of whole rock chemistry in addition to petrographic analysis combination of chemical and point count data permits the construction of normative compositions that approximate original framework grain compositions provenance analysis is also complicated in many cases by fundamental compositional alteration during weathering and transport many sandstones particularly shallow marine deposits have undergone vigorous reworking which may destroy unstable mineral grains and rock fragments in such cases it may not be possible to retrieve provenance information by either petrographic or chemical means because of this pseudomatrix rich sandstones should be routinely included in chemical petrological provenance analysis because of the many factors both pre and post depositional that operate to increase the compositional maturity of sandstones petrologic studies must include a complete inventory of matrix proportions grain size and sorting parameters and an assessment of depositional setting

development and testing of a 3d seismic velocity model of the po plain sedimentary basin italy abstract we built a 3d seismic model of the po plain and neighboring regions of northern italy covering altogether an area about 600 km by 300 km with an approximately 1 km spaced grid we started by collecting an extensive and diverse set of geological and geophysical data including seismic reflection and refraction profiles borehole logs and available geological information major geological boundaries and discontinuities have thus been identified and mapped into the model we used kriging to interpolate the geographically sparse information into continuous surfaces delimiting geological bodies with laterally varying thickness seismic wave properties have been assigned to each unit using a rule based system and v p v s and derived from other studies sedimentary strata although with varying levels of compaction and hence material properties may locally reach a thickness of 15 km and give rise to significant effects in seismic wave propagation we have used our new model to compute the seismic response for two recent earthquakes to test its performance results show that the 3d model reproduces the large amplitude and the long duration of shaking seen in the observed waveforms recorded on sediments whereas paths outside the basin may be well fit by more homogeneous 1d hard rock structure we conclude that the new model is suited for simulation of wave propagation mostly for t 3 s and may serve well as a constraint for earthquake location and further improvements via body or surface wave inversion

unit hydrograph derived from a spatially distributed velocity field a unit hydrograph model is proposed in which the watershed is decomposed into subareas which are individual cells or zones of neighbouring cells the unit hydrograph is found for each subarea and the response at the outlet to excess rainfall on each subarea is summed to produce the watershed runoff hydrograph the cell to cell flow path to the watershed outlet is determined from a digital elevation model a constant flow velocity is assigned to each cell and the time lag between subarea input and response at the watershed outlet is found by integrating the flow time along the path from the subarea to the outlet the response function for a subarea is modelled as a lagged linear reservoir in which the flow time is equal to the sum of a time of translation and an average residence time in the reservoir it is shown that the assumption of a spatially varying but time invariant velocity field underlying this model produces a linear system model for all subareas whose outputs can be summed in the manner indicated an example application is presented for the 8 70 km2 severn watershed at plynlimon in wales using a 50 m digital elevation model in which the cell velocity is calculated by modifying an average watershed velocity according to the terrain slope and the drainage area of each cell the resulting model reasonably reproduces the observed unit hydrograph