use of ground probing radar and resistivity surveys for archaeological investigations in japan geophysical methods are normally used to estimate the distribution of cultural relics before digging objects of archaeological interest are usually located within a few meters of the surface therefore geophysical methods suitable for archaeological exploration are those which provide high resolution at shallow depths the most commonly used geophysical methods are ground probing radar resistivity and magnetometry of these methods we used mainly ground probing radar and resistivity surveys in archaeological investigations at four sites three of the sites were in gumma prefecture japan they were covered with volcanic deposits loam or pumice using ground probing radar we were able to locate ancient dwellings burial mounds and a distribution of archaeologically significant culture layers at the other site in nara prefecture we located part of the remains of an ancient city in this investigation the resistivity method and ground probing radar were combined to determine the loc

fast monostatic gpr modeling we propose the exploding reflector method to simulate a monostatic survey with a single simulation the exploding reflector used in seismic modeling is adapted for ground penetrating radar gpr modeling by using the analogy between acoustic and electromagnetic waves the method can be used with ray tracing to obtain the location of the interfaces and estimate the properties of the medium on the basis of the traveltimes and reflection amplitudes in particular these can provide a better estimation of the conductivity and geometrical details the modeling methodology is complemented with the use of the plane wave method the technique is illustrated with gpr data from an excavated tomb of the nineteenth century

nd isotope composition of conodonts an accurate proxy of sea level fluctuations abstract analyses of the nd isotope composition of conodonts from the anti atlas morocco the montagne noire france and the rhenohercynian domain germany provide insight into the temporal and lateral variations in seawater geochemistry in the western part of the variscan sea during the late devonian most of the isotopic excursions accurately record changes in sea level the end values decreased during regression phases when erosion accelerated supply of unradiogenic nd from old continental sources a rise in sea level generated a positive shift in end values due to input of more radiogenic oceanic water into the seawater reservoir of the shelf areas the method has great potential for sea level research paleoceanography and correlation because sea level changes can be precisely recognized even in successions with uniform monotonous lithologies however it has a significant limitation being valid only in epeiric seas and shelf areas we have used the nd isotope record to reconstruct the eustatic sea level changes in late frasnian early famennian time the onset of the organic rich kellwasser units coincides with negative trends in end values this accords with oxygen deficiency at the sea bottom being initiated by short term regressive events which in turn would be consistent with cooling periods of glacial origin as previous authors have suggested

recognising the taghanic crisis in the devonian terrestrial environment and its implications for understanding land sea interactions the late mid devonian eday marl formation from the orcadian basin scotland is a terrestrial equivalent of the marine devonian taghanic crisis the eday marl from orkney contains a high resolution archive of climatic change controlled by the relative strength of the seasonal insolation this includes several distinct and discrete episodes of basin flooding as demonstrated by the deposition of lacustrine laminites bedded evaporites marginal sheet flood sands and marine influenced bioturbated sheet sands these flooding events are intercalated with intense and sustained episodes of aridity indicating that insolation was relatively weak and the monsoon climate was ineffective at drawing in seasonal rainfall recognition of these basin flooding events has enabled the definition of three new units the wha taing roeberry and berstane members the eday marl formation can be correlated offshore and also recognised within marginal facies as an aeolian intercalation an environmental hydrological and climatic interpretation is given for the different events recognised in the eday marl this sequence of events when combined with the palynological age dates enables a detailed correlation to be made with the marine tully formation of new york state this suggests that regressions forced by climatic aridity are significant for understanding the deposition of the shallow water carbonates of the tully formation in what is otherwise a clastic depositional system comparison with the pelagic marine record shows that the latter as yet gives only limited resolution of the taghanic crisis recognising the taghanic as a rapid alternation of cool arid and relatively hotter pluvial events provides a unifying explanation for the associated collapse in the terrestrial vegetation and the parallel faunal changes in the marine realm

disintegration of the continental margin of northwestern gondwana late devonian of the eastern anti atlas morocco the devonian early carboniferous sequence in the eastern anti atlas represents a complete record of the last stage of the depositional and tectonic evolution along the northwestern margin of gondwana as a consequence of early variscan block faulting a platform and basin topography was established during the middle and late devonian platforms were covered by condensed cephalopod limestones sedimentation in the basins was mainly argillaceous with calcareous and turbiditic intercalations in the latest famennian early tournaisian the whole area was covered by delta deposits in the south passing into turbidites and olistostromes toward a continental slope farther north this sedimentary and structural evolution reflects the gradual foundering and disintegration of the northwestern continental margin of gondwana prior to the collisional stage in the late visean late carboniferous

calibrating the devonian time scale a synthesis of u pb id tims ages and conodont stratigraphy the recalibrated devonian time scale represents an important improvement of devonian chronology regarding two aspects firstly a data set of 13 biostratigraphically well bracketed u pb id tims zircon and monazite ages constitutes the framework of the scale secondly approximately time linear biostratigraphic scales have been used for the interpolation between the isotopic ages the new construction thus represents a biochronometric time scale which allows the assignment of numeric ages not only to stage boundaries but also to each biozone boundary the method of interpolation applied also enables the projection of the geochronological error onto the time scale according to the newly calibrated scale the devonian lasted 57 4 5 7 ma from 418 1 3 0 to 360 7 2 7 ma this is compared to previously published time scales the longest time span ever calculated for this period the age interpolations for the eight stage boundaries are famennian tournaisian devonian carboniferous 360 7 2 7 ma frasnian famennian 376 1 3 6 ma givetian frasnian 383 7 3 1 ma eifelian givetian 388 1 2 6 ma emsian eifelian 391 9 3 4 ma pragian emsian 409 1 3 8 ma lochkovian pragian 412 3 3 5 ma pridolian lochkovian silurian devonian 418 1 3 0 ma full size table table options view in workspace download as csv the duration of the middle devonian is calibrated here as quite short with 8 2 ma and the emsian and the famennian are the longest stages with interpolated durations of 17 2 and 15 4 ma respectively together all devonian stages contain 57 conodont zones including subzones according to the standard conodont zonation giving a mean duration of about 1 ma in the highly resolved part of the time scale mid eifelian to the devonian carboniferous boundary zonal resolution averages 0 6 ma in contrast the lowest resolution is shown in the early emsian to mid eifelian interval with zonal durations of up to 5 5 ma serotinus zone

ground penetrating radar surveys used in archaeological investigations during 1982 and 1983 two ground penetrating radar surveys were carried out in conjunction with archaeological investigations in canada the first survey was a detailed high resolution radar survey at the site of a sixteenth century basque whaling station on the labrador coast designed to locate the graves of the basques the second was a rapid low resolution reconnaissance survey as part of a prehistory impact assessment program at the site of the new national museum of man in hull quebec both surveys were experimental and were designed to see whether ground penetrating radar would be useful for identifying and locating anomalies of archeological significance radar was successful in detecting archeological anomalies several meters in size at both locations and the high resolution survey was moderately successful in identifying basque graves ongoing work involves comparing radar results with the archaeological investigations to increase the understanding of how radar can be applied to archaeology a

thermal and burial history of the cracow silesia region southern poland assessed by conodont cai analysis abstract conodont colour alteration cai data have been applied in the reconstruction of palaeothermal conditions in the cracow silesia region southern poland the analysis of conodont cai values supplemented by electron spin resonance esr data provided a complex maturity pattern which coincides well with the tectonostratigraphical divisions of this region during the variscan and alpine diastrophic cycles the palaeozoic rocks in the upper silesian coal basin attained the observed thermal maturity during late carboniferous or permian time just after the tectonic inversion of the basin vertical maturity trends suggest that palaeo geothermal gradients were significantly higher than the present values the irregular maturity pattern recognized in the cracow myszkow zone is related to the thermal overprint of intrusive igneous rocks on the maturity field resulting from the relatively shallow burial this pattern has not been modified by mesozoic hydrothermal events the low maturity level of devonian and early carboniferous rocks in the substrate of the carpathian foredeep is a product of the subsidence during miocene time the implications for hydrocarbon generation and further exploration are discussed the cai data are consistent with other indicators of organic metamorphism previously used in this region the study highlights also features about the conodont colour alteration such as the influence of silica mobilization on conodont colour which limit the application of the cai method

stress evaluation in offshore regions of norway a review has been undertaken of all available information on crustal stresses in norwegian continental shelf and north sea the data have principally come from the results of borehole breakouts supplemented by focal mechanisms a simple model of a soft linear inclusion was developed to explain the rapid changes in stress orientation in the central graben area this example indicates that the stress field is affected locally by the geological or structural environment

insights on why graphic correlation shaw s method works in 1964 a b shaw presented a method of correlating fossiliferous sedimentary rocks based on interpretation of graphic plots of first and last occurrences of taxa because there is no way to determine the true total ranges of fossil taxa it is instructive to test the accuracy of the method using hypothetical datasets the dataset used here consists of 16 taxa in six sections with differing known rates of rock accumulation in all graphs a single straight line correlation was a reasonable interpretation the resulting ranges after the first and third rounds of compositing reproduce the true ranges but with small errors slight errors in the positioning of individual correlation lines are more likely to lengthen ranges artificially than to shorten them shaw s method works well because whereas actually sampled ranges will be shorter than true ranges errors in correlation will be likely to extend some ranges this or any exercise using simulated data is useful only if the hypothetical situation resem

late cretaceous and cenozoic intra plate compressional deformations in the alpine foreland a geodynamic model abstract the mesozoic grabens and wrench induced troughs of western and central europe developed in response to triassic early cretaceous intra plate tensional stresses which affected the arctic north atlantic and the tethys borderlands during the rifting phase preceding the opening of the respective oceans this resulted in the fragmentation of the continental crust of the alpine foreland during the late cretaceous and tertiary alpine orogeny collision related compressive stresses exerted on the foreland induced the reactivation of these fracture systems causing the inversion of mesozoic grabens and the uplifting of major basement blocks at distances up to 1300 km to the north of the present alpine deformation front the structural style of these inverted basins and basement uplifts is indicative of compressional and transpressional deformations the total amount of crustal shortening associated with these deformations is unlikely to exceed a few tens of kilometres these displacements require a coupling between the foreland and the orogen at the alpine a subduction zones and within the foreland a decoupling at intra crustal levels between the crust and mantle and or at deeper lithospheric levels the example of the alpine foreland indicates that compressive stresses inducing major deformations can be transmitted from a collisional plate boundary through continental lithosphere over distances of up to 1300 km circumstantial evidence suggests that collision related compressive stresses not large enough to give rise to significant deformations can be transmitted through continental lithosphere over even greater distances

reverse time migration migration of stacked or zero offset sections is based on deriving the wave amplitude in space from wave field observations at the surface conventionally this calculation has been carried out through a depth extrapolation we examine the alternative of carrying out the migration through a reverse time extrapolation this approach may offer improvements over existing migration methods especially in cases of steeply dipping structures with strong velocity contrasts this migration method is tested using appropriate synthetic data sets

orbital cyclostratigraphy of the devonian frasnian famennian transition in south china abstract superbundlesets bundlesets bundles and laminae were formed in the carbonate successions of the devonian frasnian famennian transition in guangxi south china their hierarchical structures ratio relationships and arrangement order within conodont zones are lasting and stable in the stratigraphical sequences and can be traced across the different facies belts and sedimentary basins the hierarchically organized superbundlesets bundlesets bundles and laminae correspond to a long eccentricity eccentricity obliquity and precession and sub milankovitch cyclothem respectively the ratio of long eccentricity to eccentricity is 1 4 below the boundary between frasnian famennian and 1 3 above the boundary between frasnian famennian eccentricity to obliquity is 1 3 and eccentricity to precession is 1 6 in the devonian since the eccentricity periodicity of 100 000 years remains essentially steady through geological time the periodicity of the long eccentricity obliquity precession and sub milankovitch cycle was 400 000 33 333 16 667 and 8000 or 17 000 years these ratios are different from those of the permian cretaceous and quaternary and coincide well with those calculated theoretically by berger et al science 255 1992 560 this reinforces the hypothesis of the slowing of the earth s rotation and the lengthening of precession and obliquity periods since at least the devonian time on the basis of the hierarchical milankovitch cyclothems the chronostratigraphical subdivision and correlation of the frasnian famennian transition can be made at the resolution of 100 000s and 10 000s of years the duration of the upper rhenana zone linguiformis zone and lower middle and upper triangularis zone is 0 6 0 8 0 3 0 3 and 0 3 ma respectively

stable isotope record of the eifelian givetian boundary kacak otomari event middle devonian from hungry hollow ontario canada the kacak event in the middle devonian eifelian givetian e g boundary is a period of apparent global anoxia coincident with widespread deposition of black shale in hemipelagic pelagic and som

how complete are cretaceous tertiary boundary sections a chronostratigraphic estimate based on graphic correlation cogent interpretations of data bearing on the cretaceous tertiary k t extinction controversy depend on the existence of accurate chronostratigraphic models for the various k t boundary sections we have employed the graphic correlation technique to summarize biostratigraphic and lithostratigraphic data from 15 intensively sampled k t boundary sections within a common chronostratigraphic model our results indicate that almost all of these sections along with 13 additional boundary sections not used to construct the model contain prolonged and in many cases multiple hiatuses of these 28 boundary sections only six were found to contain a continuous record of sediment accumulation across the k t boundary itself these six k t complete sections are el kef tunisia agost spain caravaca spain and three sections along the brazos river texas a comparative analysis of hiatus distributions among these 28 k t boundary sections also reveals the presence of systematic differences between continental shelf and deep sea depositional environments the lower danian interval immediately following the k t boundary and extending into biochronozones p0 and p1a is typically missing from the deep sea whereas boundary sections deposited in shallower middle neritic to upper slope environments are in most cases complete across the k t boundary these shallow neritic boundary sections however are in many instances disrupted by hiatuses at the p0 p1a boundary and again in the upper part of zone p1a these differential patterns of hiatus distribution between deep sea and continental shelf depositional settings appear to be linked to sea level fluctuations our data suggest that the apparently sudden mass extinction of planktonic foraminifera and anomalies in the occurrence of geochemical tracers that are characteristic of the k t boundary in deep sea sections may be artifacts of a temporally incomplete deep sea stratigraphic record

chronometric calibration of mid ordovician to tournaisian conodont zones a compilation from recent graphic correlation and isotope studies three available graphic correlation analyses are used to calibrate mid palaeozoic conodont zonations sweet s scheme for the mid to upper ordovician kleffner s for the mid to upper silurian and murphy berry s for the lower and middle lower devonian the scheme of sweet is scaled by applying the high precision u pb zircon date of tucker and others for the rocklandian and linked with that of kleffner by scaling the graptolite sequence of the ordovician silurian global stratotype section to fit two similarly derived dates from this sequence the top of kleffner s scheme all of murphy berry s as well as standard zones to the frasnian are calibrated by using tie points of the latest cambridge bp time scale gts 89 however the recent microbeam zircon date by claoue long and others for the hasselbachtal devonian carboniferous auxiliary stratotype is used to calibrate the standard famennian zones also the similarly derived but preliminary determination reported by roberts and others from the isismurra formation of new south wales is tentatively taken as the top of the tournaisian and so used to calibrate tournaisian zones despite the considerable extrapolation required to compile these schemes and their inherent errors the resultant time scale closely agrees with other dates of tucker and others from the llanvirn as well as the gts 89 homerian gorstian tie point this suggests that stratigraphic methods can be usefully applied to geochronometry the llandovery appears to have lasted longer 16 m y than usually envisaged and the ordovician silurian boundary may need to be lowered to approximately 443 5 ma certainly chrons varied widely in duration and further stratigraphic studies to estimate their relative durations as well as high resolution dating for their calibration will be crucial to more accurate biochronometries

the search for graves over the decades grave markers in old cemeteries have been lost geophysical exploration can sometimes locate the unmarked burials the two techniques which may be best for this search are a ground penetrating radar survey and a soil conductivity survey a ground penetrating radar survey with its capability for estimating the depth and shape of buried objects is particularly suitable with an electromagnetic induction survey the disturbed soil in the grave shaft can sometimes be detected as a change in electrical conductivity both of these surveys also can locate large metal objects these surveys have limitations at some sites the radar cannot profile deeply enough at others the soil strata are so complex that graves cannot be distinguished a conductivity survey can be degraded by metallic trash and other small objects in the topsoil it can give the best results where the earth is distinctly stratified results from nine surveys are illustrated here the sites are all in the u s a and the gra

full wave calibration of time and frequency domain ground penetrating radar in far field conditions full wave modeling of ground penetrating radar gpr data using green s functions for wave propagation in planar layered media and antenna characteristic global reflection and transmission functions for describing far field antenna effects including antenna medium interactions has shown a great potential for nondestructive characterization of soils and materials the accuracy of the retrieved parameters in the gpr data inversion depends on the accuracy of the gpr external calibration in this research we studied the stability and the repeatability of two different gpr systems namely frequency and time domain systems a combination of a vector network analyzer and 800 5200 mhz horn antenna was used as a frequency domain gpr fd gpr whereas a gssi gpr system using a 900 mhz bowtie antenna was used as a time domain gpr td gpr both gpr systems including their antennas were calibrated several times using measurements with the antennas at different heights over a perfect electric conductor pec in the laboratory as well as over a water layer in addition measurements were performed over a thin water layer and a relatively thick sandy soil layer as validating medium the results showed that the fd gpr is relatively stable while the td gpr presents a significant drift which can be accounted for using corrections based on the air direct coupling waves free space measurements water and pec based calibrations provided very similar results for the gpr calibration functions inversions for the water layer and the sandy soil layer provided reliable results and showed a high degree of the repeatability for both radar systems the error on the calibration based on inaccurate antenna heights over pec showed the significant errors on the inversion results for the directive antenna horn antenna but less error for the bowtie antenna this analysis demonstrated the general validity of the proposed far field radar modeling approach not only with respect to frequency and time domain radars but as well with respect to the calibrating medium

a climate driven model using time series analysis of magnetic susceptibility χ datasets to represent a floating point high resolution geological timescale for the middle devonian eifelian stage

regional patterns of tectonic stress in europe nearly 1500 stress orientation determinations are now available for europe the data come from earthquake focal mechanisms overcoring measurements well bore breakouts hydraulic fracturing measurements and young fault slip studies and sample the stress field from the surface to seismogenic depths three distinct regional patterns of maximum compressive horizontal stress shmax orientation can be defined from these data a consistent nw to nnw shmax stress orientation in western europe a wnw ese shmax orientation in scandinavia similar to western europe but with a larger variability of shmax orientations and a consistent e w shmax orientation and n s extension in the aegean sea and western anatolia the different stress fields can be attributed to plate driving forces acting on the boundaries of the eurasian plate locally modified by lithospheric properties in different regions on average the orientation of maximum stress in western europe is subparallel to the direction of relative plate motion between africa and europe and is rotated 17 clockwise from the direction of absolute plate motion the uniformly oriented stress field in western europe coincides with thin to medium lithospheric thickness approximately 50 90 km and high heat flow values 80 m w m2 in western europe a predominance of strike slip focal mechanisms implies that the intermediate principal stress is vertical the more irregular horizontal stress orientations in scandinavia coincide with thick continental lithosphere 110 170 km and low heat flow 50 m w m2 the cold thick lithosphere in this region may result in lower mean stresses associated with far field tectonic forces and allow the stress field to be more easily perturbed by local effects such as deglaciation flexure and topography the stress field of the aegean sea and western anatolia is consistent with n s extension in a back arc setting behind the hellenic trench subduction zone the stress field is influenced in places by regional geologic structures e g in the western alps where shmax directions show a slight tendency toward a radial stress pattern not all major geologic structures however appear to affect the shmax orientation e g in the vicinity of the rhine rift system horizontal stress orientations are continuous

conodont based quantitative biostratigraphy for the eifelian of the eastern anti atlas morocco the measured ranges of 52 conodont taxa present in 7 eifelian sections of the eastern anti atlas in southern morocco have been as sembled by graphic correlation method into a chronostratigraphic framework the anti atlas regional composite developed in this study provides much higher stratigraphic res olution than the traditionally used conodont zonation it allows a subdivision of the eifelian into 65 7 composite standard units derived from the jebel ou driss section which was se lected as the standard reference section the framework appears to have a linear fit to time giving the first image of the relative duration of the conodont zones in the upper emsian to lower givetian interval the costatus kockeli anus and lower varcus chrons appear to have lasted more than two times longer than the partitus australis and or hemiansatus chrons an alternative upper eifelian lower givetian conodont zonation with zones of more equal duration is proposed several conodont index taxa in the anti atlas area display an almost synchronous appearance independent of fa cies conditions and shelf paleobathymetry the analysis by graphic correlation reveals significant differences in rate of sediment accu mulation between the tafilalt platform which had condensed sedimentation 2 5 m m y and the mader basin characterized by rates up to 40 m m y area the devonian rocks offer excellent condi tions for detailed biostratigraphical studies their depositional history reflects the process of disin tegration of the northern margin of the sahara cra ton wendt 1985 1988 in contrast to the rather uniformly developed upper silurian and lower devonian sedimentary rocks differential subsi dence affected the area during eifelian time and thus a platform to basin topography of the shelf began to originate this phase is biostratigraphi cally relatively well constrained conodonts were found in many sections providing a base for cor relation of eifelian rocks in the anti atlas bul tynck and hollard 1980 bultynck and jacobs 1981 bultynck 1985 1987 1989 1991 the fauna dominated by polygnathus elements is lo cally very abundant but some stratigraphically important eifelian index taxa are rare or absent so that the position of some zonal boundaries e g the base of the eifelian cannot be precisely rec ognized this is why bultynck 1987 proposed two alternative conodont zonations for the upper eifelian lower givetian interval in order to provide a more accurate basis for correlation of eifelian rocks and events in north ern africa we used the graphic correlation method to develop a composite standard section based on conodont data from the eastern anti at las our regional chronostratigraphic framework anti atlas regional composite provides a much more linear biostratigraphic subdivision than any previously used conodont zonation it offers moreover the best possible stratigraphic resolu tion useful for detailed analysis of the sedimen tary evolution of the study area during the middle devonian this contribution constitutes a first ap proach in the construction of the eifelian com posite standard with worldwide applicability in conventional biostratigraphy fossil zones are used to achieve correlation the graphic cor relation technique however produces a frame work that is founded on biostratigraphy but inte grates all the biostratigraphic events onto a composite standard this method was developed by shaw 1964 and was subsequently extended e g miller 1977 sweet 1979 edwards 1984 1989 to be applicable to nonpaleontologic and nonunique but chronostratigraphically signifi cant events including magnetic polarity data key lithological marker beds various geophysical log type data and stable isotope logs it constitutes a powerful tool for the analysis of synchroneity or nonsynchroneity of geologic events integrated with sequence stratigraphy and sedimentological data shaw s method of graphic correlation is one of the standard techniques applied in modern basin analysis e g neal et al 1994 geologic setting

tertiary compressional structures on the faroe rockall plateau in relation to northeast atlantic ridge push and alpine foreland stresses abstract a number of compressional anticlinal structures are identified in the western and northern part of the faroe rockall plateau these structures occur on that part of the faroe rockall plateau which was above sea level during the latest phase of paleocene plateau basalt extrusion three post basalt compressional phases have affected the plateau most of the compressional structures in the northern part of the plateau are related to ne sw to ene wsw oriented stress which we date to late paleocene early eocene the oligocene phase is interpreted as resulting from n s directed compressional stress which also mainly affected the compressional structures on the northern part of the plateau compressional stress from the northwest seemed to affect the whole of the faroe rockall plateau and we suggest it to be of miocene age it is proposed that during the late paleocene early eocene phase of compression local structure and anomalously oriented gravitational ridge push from the now extinct aegir axis contributed to a local ne sw compressional stress system the two later deformation phases were apparently connected to the regional northwest european stress system with small local modifications