fluvial responses to tectonics and climate change during the late weichselian in the eastern part of the pannonian basin hungary abstract fine grained sandy silty channel belt and floodplain deposits of the berettyo koros rivers a main eastern transverse tributary system of the modern tisza river in the eastern part of the pannonian basin were deposited during the late pleistocene under net subsiding conditions the palaeo drainage network pattern of a 2500 km 2 large part of the alluvial plain was reconstructed based on interpretation of airborne photographs and analysis of 18th century topographic maps which show the natural river patterns that predate the introduction of river regulation schemes the investigation showed that a large meandering river system with two main channel belts surrounding a floodbasin entered the alluvial plain from the northeast and a braided river entered the alluvial plain from the southeast detailed sedimentary logs of seven continuous corings and several sand and clay pit sections were used to characterize different alluvial units optical luminescence dating osl of 25 quartz samples and four 14 c datings showed that the sediments are of late pleniglacial to late glacial age transport directions inferred from heavy mineral analyses combined with the osl ages strongly suggest that the large meandering system represents the palaeo tisza river which supposedly flowed along the northeast southwest striking ermellek depression during the late pleniglacial the braided river can be regarded as a precursor to the fekete and feher koros rivers which entered the alluvial plain from the southeast during the late glacial the interpretation of seismic profiles field measurements of neotectonic activity and variations in thickness of sediments along the studied profile revealed that river development was largely controlled by subsidence along the ermellek depression until 14 to 16 ky and by uplift of the southeastern part of the catchment area the studied fluvial successions also document the response of the palaeo tisza and koros system to the climate changes of the weichselian late pleniglacial late glacial period much of the sand from the meandering zones was deposited during the bolling allerod and sagvar lascaux interstadials whereas some dated sand units from the braided zone represent the older and younger dryas the error ranges of osl dates which often exceed the duration of weichselian substages and subdivisions prevented an unambiguous correlation of the studied sections with the millennial scale climate changes of the last 25 ky meandering and braided river activity coexisted under different climate conditions whereas locations of the main channel belts are related to subsidence anomalies the results of our study thus clearly indicate that tectonics was the primary control on river development

evolution of oceanic lithosphere a driving force study of the nazca plate the role of the evolution of oceanic lithosphere in driving oceanic plates is tested with elastic and viscous finite element modeling of the nazca plate results indicate that ridge push forces when distributed over that portion of the oceanic lithosphere giving rise to the force predict a stress state that varies more spatially than does previous modeling with ridge forces concentrated at the ridge crest in particular the component of stress normal to the ridge vanishes near the ridge for the new modeling predicted stresses for distributed ridge force models are still in qualitative agreement with the limited data on nazca intraplate stress stress states have also been calculated for a variety of slab pull models which include possible dependence on age rate and angle of subduction the predicted stresses vary substantially near the trench among these models with less variation farther from the trench combinations of ridge push and slab pull models are consistent with the earlier result of ah upper limit of about a factor of 2 for net slab pull over ridge push simple viscous modeling with only distributed ridge forces predicts relative motion between the nazca and south american plates that is in fairly poor agreement with the observed direction the fit to the observed direction could probably be improved by either including slab forces or the effect of the largely transform boundary with the antarctic plate

an extensive region of off ridge normal faulting earthquakes in the southern indian ocean an unusually large number of off ridge earthquakes have occurred within a broad region astride the southeast indian ridge the source mechanisms of nine of these earthquakes in lithosphere from 4 to 27 m y old have been determined with a formal inversion technique based on matching observed and synthetic p and sh waves all events occur in the oceanic mantle from 8 to 22 km below the seafloor the seismic moment and duration of faulting obtained from the inversion constrain the stress drop to lie between a few tens of bars and a few hundred bars for most of the events all of the off ridge earthquakes are characterized by normal faulting mechanisms with the t axes nearly parallel to the nearby ridge axis in sharp contrast to typical mid ocean ridge or intraplate earthquakes a variety of possible tectonic processes which might produce normal faulting in young oceanic lithosphere are considered as possible causes including bending stresses thermal stresses of various origins differential subsidence at a fracture zone off ridge volcanism latitudinal plate motions on a nonspherical earth basal shear stress from small scale convection and plate wide perturbations of the stress field due to the continental collision between india and asia no single mechanism is adequate to explain all the observed off ridge normal faulting earthquakes an apparent asymmetry in the observed seismicity with respect to the ridge suggests that the earthquakes on the antarctic and indian plates are caused by different processes the antarctic plate events can be satisfactorily attributed to the release of thermal and bending stresses associated with a residual depth anomaly between the kerguelen plateau and the southeast indian ridge a region which has been suggested as the site of a horizontal pipe for flow in the asthenosphere from the kerguelen hot spot to the vicinity of amsterdam and st paul islands on the southeast indian ridge the off ridge earthquakes in the indian plate are speculatively attributed to part of the plate wide response of the lithosphere to the ongoing continental collision

revealing the coastal event history of the andaman islands bay of bengal during the holocene using radiocarbon and osl dating earthquakes that trigger tsunamis are of great geological ecological and socio economic importance the knowledge of the recurrence interval of these events will give information about the hazard for a region coastal sediments on the andaman islands located in the eastern bay of bengal were investigated to find evidence for palaeotsunamis and palaeoearthquakes fieldwork was conducted on red skin island and north cinque island south of south andaman sediment material from event layers was dated by optically stimulated luminescence and radiocarbon dating method the results show evidence possibly for one earthquake at about 1 000 or 3 000 years before the present together with deposits from possible tsunamis and storms the complex pattern of co and post seismic uplift and subsidence of the andaman islands is reflected in the investigated sections and made it possible to reconstruct an event history for the last 3 000 years

statistical tests of additional plate boundaries from plate motion inversions we have investigated the application of the f ratio test a standard statistical technique to the results of relative plate motion inversions the method tests whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance this approach appears to be useful in determining whether additional plate boundaries are justified we confirm previous results favoring separate north american and south american plates with a boundary located between 30 n and the equator using chase s global relative motion data we show that in addition to separate west african and somalian plates separate west indian and australian plates with a best fitting boundary between 70 e and 90 e can be resolved these results are generally consistent with the observation that the indian plate s internal deformation extends somewhat westward of the ninetyeast ridge the relative motion pole is similar to minster and jordan s and predicts the nw se compression observed in earthquake mechanisms near the ninetyeast ridge

depth determination for shallow teleseismic earthquakes methods and results the depths of moderate sized shallow earthquakes can be routinely determined to an accuracy of several kilometers using teleseismic data alone making it possible to determine the vertical positions of earthquakes within the lithosphere this capability provides a valuable tool for plate tectonic studies since earthquake depths can be used to constrain lithospheric thermal and mechanical structure at plate boundaries and in intraplate regions two basic techniques are used for depth analyses surface wave spectra can be used to determine focal depths as mode excitation reflects the behavior of the eigenfunctions with depth the primary limitation on such studies stems from lateral heterogeneity of velocity structure the waveforms of body waves are also diagnostic of focal depth which controls the time separation between the direct arrival and near source surface reflections these studies can be limited by a partial trade off between depth and source time function duration the reliability of the body wave modeling approach now in general use is shown by excellent agreement between depths determined by different investigators using different algorithms the depth determination is robust to typical uncertainties in focal mechanism and near source structure the trade off with source time function duration generally does not produce major difficulties for small events ms 6 5 for larger events the trade off can be resolved using a approach in which for a given depth the time function yielding the best fit to a suite of seismograms is found by deconvolution deconvolution at a series of depths yields a misfit function whose minimum indicates the focal depth tests with synthetic data show that the deconvolution process yields reliable depth estimates even given uncertainties in focal mechanism and near source structure it successfully handles multiple sources moderate sized finite sources and horizontally propagating ruptures good results are obtained for vertically propagating ruptures until the fault area becomes so large that waveforms differ significantly from the point source approximation a number of important tectonic results have emerged from studies using these depth determination methods the maximum depth of oceanic intraplate seismicity increases with lithospheric age and is approximately bounded by the 750 c isotherm this depth roughly equals the flexural thickness of the lithosphere but is much less than the depth to the low velocity zone indicated by surface wave dispersion the maximum depth of continental intraplate seismicity is also temperature limited but by a lower temperature these observations are consistent with the rapid weakening of the appropriate rocks with depth predicted by standard temperature dependent rheologies the maximum depth of oceanic transform seismicity corresponds to an isotherm of about 400 c this temperature is lower than would be predicted from the intraplate results and may indicate that transforms are either hotter or weaker than expected the depths of ridge crest earthquakes large enough for teleseismic analysis are extremely shallow 0 8 km the depth distribution of seismicity in continental normal faulting regions provides constraints on the nature of the extension process at subduction zones precise depth determinations can resolve the upper and lower flexural regions in the bending downgoing plate precisely locate the plate interface and map the vertical extent and position of faulting in large earthquakes

intraplate seismicity and stresses in young oceanic lithosphere we have conducted a systematic study of oceanic intraplate seismicity in the period 1964 1983 occurring in lithosphere younger than 35 million years focal mechanisms determined for 26 events using first motions p wave modeling and surface wave amplitude radiation patterns along with 13 previously determined mechanisms indicate a diversity of faulting styles and stress orientations in young oceanic lithosphere there is no evidence for a worldwide transition from extension to compression at a specific lithospheric age tensional axes of normal faulting events are oriented oblique to the spreading direction and do not show extension in the spreading direction congressional axes of thrust events show a weak preferred orientation in the spreading direction presumably due to ridge push stresses however stress axes of thrust events in very young lithosphere age 9 ma do not show a correlation with the spreading direction suggesting that the ridge push force is small near the ridge these observations indicate that tensional stress in the spreading direction is concentrated in a very narrow zone at the ridge axis in agreement with models which assume that the axial region has very little tensile strength normal faulting events occur at greater depths and temperatures than thrust events possibly because rocks under tensional stress have strength maxima at higher temperatures alternatively the depths of the normal faulting events may be a result of the higher thermal gradients at depth in young lithosphere if thermoelastic stresses are important in generating this seismicity differential thermal contraction along fracture zones does not seem to be a significant source of near ridge intraplate seismicity high seismicity rates in young lithosphere noted previously on a global scale seem characteristic of all three major ocean basins additionally most of the total oceanic intraplate moment release takes place in young lithosphere however most of the events and more than 96 of the total moment release of the near ridge intraplate seismicity are contained in five areas two zones in the indian ocean one near chagos bank and the other in the amsterdam st paul region indicate tension parallel to the trend of the plate boundary a region of high seismicity near the east pacific rise between 3 and 7 n shows both normal and thrust faulting while another region on the cocos plate west of the panama fracture zone is characterized by strike slip faulting thrust strike slip and normal faulting events are found in a small seismically active zone of the south central pacific the extremely uneven distribution of seismicity if not a result of the relatively short time period studied 20 years indicates local perturbations strongly affect near ridge seismicity

loess chronostratigraphy in eastern croatia a luminescence dating approach abstract in eastern croatia impressive loess palaeosol successions up to 30 m thick are exposed along the steep cliffs of the danube river between zmajevac and sarengrad the croatian loess record provides an excellent high resolution archive of climate and environmental change providing evidence for the interaction between accumulation and erosion of aeolian and fluvial sediments during the middle and late pleistocene sedimentological and pedological investigations including granulometry carbonate content and total organic carbon content and infrared optically stimulated luminescence irsl dating were carried out on samples collected from the loess sections at zmajevac erdut and sarengrad the loess successions are intercalated by at least four palaeosols or pedocomplexes which very likely correlate with middle and upper pleistocene interstadials and interglacials in all sediment successions investigated alluvial sediments are intercalated in the loess deposits indicating periods of fluvial activity the stratigraphically youngest alluvial sediments are exposed at the erdut section loess sandwiching these alluvial sediments yielded irsl age estimates of 61 5 6 2 and 53 8 5 4 ka the irsl age estimates give evidence for periods of increased accumulation of dust during the middle and late pleniglacial correlating with oxygen isotope stage ois 3 and ois 2 respectively during the penultimate glaciation and at least the antepenultimate glaciation however it is likely that irsl age estimates 60 ka are underestimated

lateral extrusion in the eastern alps part 1 boundary conditions and experiments scaled for gravity lateral extrusion encompasses extensional collapse gravitational spreading away from a topographic high in an orogenic belt and tectonic escape plane strain horizontal motion of wedges driven by forces applied to their boundaries in the eastern alps it resulted from 1 an overall northerly compression apulia against eurasia 2 a strong foreland bohemian massif 3 lack of constraint along a lateral boundary carpathian region and 4 a previously thickened gravitationally unstable thermally weakened crust eastern alpine orogenic belt six indentation experiments reproduce lateral extrusion at lithospheric scale the models have two to four lithospheric layers with a mohr coulomb rheology for the upper and a viscous rheology for the lower crust the lithosphere rests upon a low viscosity asthenosphere a broad indenter a narrow deformable area and a weakly constrained eastern margin fullfill as closely as possible conditions in the eastern alps indentation produces both thickening in front of the indenter and escape of triangular wedges lateral variations in crustal thickness become attenuated by gravitational spreading the overall fault pattern includes domains of reverse strike slip oblique normal and pure normal faults strike slip faults in conjugate sets develop serially the narrow width of the deformable area and the strength of the foreland determine the angles between the sets gravitational spreading produces a rhombohedral pattern of oblique and pure normal faults along the unconstrained margin opposite the unconstrained margin the indenter front shows thrusts and folds intersecting with the conjugate strike slip sets a triangular indenter favors spreading high velocity of indentation favors escape high confinement limits lateral motion inhibits spreading and favors thickening lateral extrusion in the eastern alps is best modeled by 1 a weak lateral confinement 2 a broad and straight indenter 3 a narrow width of the deformable area and 4 a rigid foreland crustal thickening lateral escape and gravitational spreading all contribute to the overall deformation

folding of oceanic lithosphere folding of the lithosphere just south of the bay of bengal appears as 1 undulations in acoustic basement topography and 2 as linear geoid undulations in the seasat altimeter data from the seasat data we find that the east west trending folds have wavelengths ranging from 130 to 250 km and clustering about 190 km the horizontal gravity disturbances due to the folds range in amplitude from 15 to 50 mgal elastic models of oceanic lithosphere have in the past been used to demonstrate the implausibility of lithosphere buckling or folding in response to compression these elastic models typically predict that compressive stresses of about 5 gpa are required to buckle oceanic lithosphere with an age comparable to that of the northeastern indian ocean 40 70 ma these stresses exceed the strength of lithospheric rock we use an elastic plastic model to show that oceanic lithosphere of this age should have a net compressive strength equal to about 12 of the elastic buckling stress we further demonstrate that loads approaching the net compressive strength cause the lithosphere to fold with a wavelength about 200 km i e the wavelength observed from seasat our results reinforce earlier speculation that this folding may be related to the himalayan orogeny

the impact of glaciers on the runoff and the reconstruction of mass balance history from hydrological data in the tropical cordillera blanca peru a 41 years series of runoff and precipitation data from the peruvian cordillera blanca demonstrates the high hygric seasonality in this tropical high mountain range in this area glaciers have a crucial impact on runoff which is of essential importance for the highly populated and cultivated valley of the callejon de huaylas particularly during the dry season whereas the mid latitudes glacier runoff amplifies the seasonal variation of runoff the effect of glaciers in the low latitudes is a smoothing one it decreases clearly with the decreasing degree of glaciation in addition particular circumstances of this tropical environment allow the reconstruction of a glacier mass balance history from the hydrological data for the second half of the 20th century it shows a high synchronicity with the global trend of periods with glacier mass loss and gain comparison with length variations of three individual glaciers indicate a rather fast reaction of these glaciers to changes in mass balance although the mass balance variations show some differences among the individual catchment basins the over all trend is uniform a general positive correlation of mass balance variations with soi is obvious but not regular

miocene pliocene tectonic evolution of the slovenian periadriatic fault implications for alpine carpathian extrusion models the periadriatic line pal is a remarkable several hundred kilometer long fault system of the alpine orogen its dextral character was documented by several authors using diverse criteria but detailed kinematics and timing of movements had not been investigated along its whole length structural and paleomagnetic measurements mapping and stratigraphic and sedimentological studies have helped to unravel the miocene pliocene evolution of the slovenian segment of the pal brittle deformation was characterized by nw se to n s compression and perpendicular tension deformation has resulted in dextral strike slip faulting folding and tilting of beds the first transpressional event corresponds to the first phase of lateral extrusion of the east alpine western carpathian northern pannonian block in the early miocene 24 17 5 ma after a short period of transtension during the karpatian 17 5 16 5 ma dextral transpression reoccurred during the middle miocene to pliocene and lasted up to the quaternary middle miocene dextral slip can be connected to the second phase of extrusion the highly deformed rocks within the dextral shear zones show variable clockwise sometimes counterclockwise rotations the mechanism of rotation seems to be complex ranging from regional rotation to local folding due to pure or simple shear domino type rotation

glacier recession and water resources in peru s cordillera blanca the tropical glaciers of the cordillera blanca peru are rapidly retreating resulting in complex impacts on the hydrology of the upper rio santa watershed the effect of this retreat on water resources is evaluated by analyzing historical and recent time series of daily discharge at nine measurement points using the mann kendall nonparametric statistical test the significance of trends in three hydrograph parameters was studied results are interpreted using synthetic time series generated from a hydrologic model that calculates hydrographs based on glacier retreat sequences the results suggest that seven of the nine study watersheds have probably crossed a critical transition point and now exhibit decreasing dry season discharge our results suggest also that once the glaciers completely melt annual discharge will be lower than present by 2 30 depending on the watershed the retreat influence on discharge will be more pronounced during the dry season than at other periods of the year at la balsa which measures discharge from the upper rio santa the glacier retreat could lead to a decrease in dry season average discharge of 30

mass balance model parameter transferability on a tropical glacier we explore the small scale spatial and temporal transferability of model parameters between two points in the ablation zone of tropical glaciar shallap cordillera blanca peru 9 s 77 w 4800 m a s l in order to provide a robust assessment of the performance of a process based glacier mass balance model relative surface height change is calculated at hourly time steps and cumulative values are compared to surface height measurements made at irregular intervals 14 64 days over the course of two continuous hydrological years august 2006 august 2008 best performing parameter combinations were determined for each point from the outcome of 1000 model simulations for which parameters were varied randomly within a defined range with these parameter combinations measurements for a specific location and time span are well reproduced transferring the parameter combination as optimized for one location to the other location in the ablation zone increases the errors of modeled cumulative mass balance by 5 1326 mm ice eq a 1 transferring the parameter combinations as optimized for one year to the other year increases the modeled errors in cumulative mass balance by 18 3179 mm ice eq a 1 model errors generally increase during periods with frequent snowfall and snow cover this could reflect either the inherent difficulty of modeling complex snow processes or the inability of the model to correctly capture the pattern of albedo evolution at this site the magnitude of errors associated with parameter transfer in space and time highlights the need for improving model performance for robust climatological and or hydrological analyses on tropical glaciers

dating of a last glacial loess sequence by relative geomagnetic palaeointensity a case study from the middle danube basin suttő hungary abstract a thorough rock and palaeomagnetic investigation of an almost 13 m thick upper pleistocene loess palaeosol sequence lpss outcropping near the village of sutt in northern hungary was conducted to obtain rock magnetic and palaeomagnetic based chronostratigraphies the results of our rock magnetic investigations indicate that the classical chinese model of magnetic enhancement showing increasing concentration dependent rock magnetic parameters in the course of pedogenesis is also valid for the northern carpathian basin we constructed a relative geomagnetic palaeointensity rpi record for the central part of the section by using the natural remanent magnetisation nrm after demagnetisation in alternating fields of 15 mt and by employing anhysteretic remanent magnetisation arm low field susceptibility k lf and saturation remanent magnetisation s irm as normalisers the three obtained rpi data sets show almost identical trends and are therefore regarded as reliable recorders of the palaeointensity of the earth s magnetic field the obtained rpi record allows for indirect dating of the lpss at sutt by correlation with the glopis and the piso stack the derived age model is in agreement with the osl based chronostratigraphy but contradicts the chronology based on the correlation between the susceptibility record and marine isotope stratigraphy mis which gives rise to the hypothesis of a possible decoupling of the palaeoclimate in the carpathian basin and the marine realm during early mis 3

why does near ridge extensional seismicity occur primarily in the indian ocean abstract the possibility that thermoelastic stresses due to plate cooling contribute significantly to the stress field and seismicity in young oceanic lithosphere has been a subject of considerable recent interest this effect is suggested by three key observations a decrease in seismicity with lithospheric age the fact that focal mechanisms show extension perpendicular to the spreading direction and a depth stratification of mechanism types a difficulty with this idea is that although thermoelastic stresses should be comparable in different regions the intraplate seismicity seems to occur in local concentrations in particular the ridge parallel extensional seismicity occurs preferentially in the central indian ocean region we explore the possibility that much of the data favoring thermoelastic stresses can be interpreted in terms of stresses resulting from individual plate geometry and local boundary effects in particular the dramatic concentration of extensional seismicity in the central indian ocean region is consistent with finite element results for the intraplate stress incorporating the effects of the himalayan collision and the various subduction zones the ridge parallel extensional stresses show a decrease with age similar to that of the seismicity as earthquakes in this area provide a major portion of the data for both ridge parallel extension and depth stratification these effects may be due more to the regional stress we thus propose that thermoelastic stresses provide a low level background in all plates but that the dominant effect is that of individual plate geometry and local boundary effects

the climate of the altiplano observed current conditions and mechanisms of past changes abstract the large scale controls on the climate of the south american altiplano are investigated using local observations reanalysis data and general circulation model experiments the objective is to gain understanding of causes of climate variability and climate change by relating mechanisms that operate on timescales ranging from the intraseasonal to the glacial interglacial our results suggest that on all timescales the climatic conditions on the altiplano are closely related to the upper air circulation with an easterly zonal flow aloft favoring wet conditions and westerly flow causing dry conditions different factors influence the upper air circulation on the different timescales intraseasonal variability is a reflection of the position and intensity of the bolivian high which is modulated by rossby waves emanating from the midlatitude south pacific the annual cycle of dry winter and wet summer conditions is caused by the seasonal expansion of the equatorial easterlies in the upper troposphere rather than direct insolation forcing over the altiplano or moisture changes in the source area interannual variability is primarily related to changes in the mean zonal flow over the altiplano reflecting changes in meridional baroclinicity between tropical and subtropical latitudes which in turn is a response to sea surface temperature changes in the tropical pacific orbitally forced changes in the land sea contrast drive continental scale circulation changes which significantly alter the zonal flow over the altiplano on glacial interglacial timescales the contrast in heating between northern and southern hemispheres during the glacial leads to upper air easterly anomalies throughout the tropics on modern timescales the marked submonthly seasonal and interannual changes of moisture over the altiplano cannot be accounted for by moisture changes in the humid tropical lowlands however the model experiments suggest that cooler conditions during a glacial reduce moisture availability from the tropical lowlands which counteracts the effect of the upper level circulation resulting in little overall change in precipitation this observational and modeling analysis provides a physical framework for relating the mechanisms of both internal and forced climate change on the altiplano on a wide range of timescales

the geochronology of the gorjanovic loess section in vukovar croatia abstract along the right bank of the danube river in croatia up to 30 m thick loess palaeosol sequences are exposed a detailed geochronological study was performed on the gorjanovic loess section at vukovar by the means of infrared stimulated luminescence irsl dating the section consists of loess intercalated by three palaeosols and a tephra layer fourteen samples were collected and dated using the elevated temperature post ir irsl protocol a modified single aliquot regenerative dose sar protocol for the equivalent dose de determination on fine grained polymineral material both the irsl signal at 50 c and the post ir irsl signal at 225 c were recorded fading tests were performed for both signals and the ages were fading corrected the loess palaeosol sequence can be correlated to the penultimate glacial last interglacial last glacial period mis6 mis2 an even older loess record at the site under study was previously described but is not exposed anymore owing to the embankment the fading corrected irsl and the fading corrected post ir irsl results are in excellent agreement the post ir irsl signal at 225 c shows less fading than the irsl signal at 50 c and can successfully be used for the dating of older loess

neogene quaternary structures in the border zone between alps dinarides and pannonian basin hrvatsko zagorje and karlovac basins croatia analysis of neogene quaternary structures from seismic lines surface measurements and geological mapping is presented from the border zone between the alps dinarides and pannonian basin first early miocene extension was possibly characterised by ene directed extension it was partly synchronous with nw se shortening second middle miocene extension was possibly characterised by nw se to wnw ese directed extension again this event was followed by a new generation of thrusts related to end sarmatian shortening the last late miocene e w to wnw ese directed extension was followed by a final shortening that created major map scale folds basement pop ups and inverted former basins geometry onlap and thickness patterns of the youngest syn tectonic basin fill indicate that this last n s to nw se directed shortening started in late pontian and continued up to the present time when taking into account the wider surrounding area it seems that the structures related to this latest shortening are arranged in often perpendicular directions centred at the eastern end of the periadriatic lineament to explain this fan like pattern of synchronous shortenings a kinematic model is proposed combining counter clockwise rotation with north or northwestward shift of the dinaridic block with respect to the more stable alpine buttress

basin and river profile morphometry a new index with a high potential for relative dating of tectonic uplift abstract geomorphometry may be a powerful tool to describe the characteristics of the landscape s response to tectonic signals but the meaning of morphometric indices is often obscured by the interplay between the many variables controlling the geomorphological evolution moreover although the so called hypsometric integral refers to the basin scale most indices are generally derived from the river long profiles and thus focus mainly on the short term response of a drainage network to base level change providing limited information in regions of older and or moderate uplift here using the rhenish shield western europe an area of moderate quaternary uplift as a test case i attempt to build an index yielding a comprehensive view of the stage attained by the landscape s response and indirectly an evaluation of the timing of the triggering base level change this index called r 1 is a ratio of differences between the three integrals linked respectively to the classical basin s hypsometric curve to the main river s long profile and at the intermediate level to a drainage network s hypsometric curve while its ratio form minimizes the lithological effect on r 1 this index is strongly correlated with basin size regional correlation coefficients are in the range 0 88 0 93 reflecting the way an erosion wave propagates from the outlet of a basin toward its headwaters therefore it is not directly usable as a proxy for relative uplift age however one can show that the relation between r 1 and basin size is theoretically expected to change with time following uplift the slope s r of the linear relation r 1 f ln a first increases rapidly but briefly then it gradually diminishes over several million years this is fully confirmed by the analysis of r 1 and s r in the study area once its initial increase is completed assumedly in a few ten thousand years s r appears to be a reliable indicator of relative uplift or any other cause of base level lowering age

intraplate earthquakes and the state of stress in oceanic lithosphere abstract the sources of stress responsible for oceanic intraplate earthquakes and their usefulness for inferring the tectonic stress field are investigated through a synthesis of the source mechanisms of 58 of the largest such events determined by inversion of long period p and sh waveforms further constraints are provided by the global distribution of oceanic intraplate seismicity and a calculation of the seismic moment release per unit volume of seismogenic lithosphere as a function of lithosphere age although frequently associated with relict tectonic features large oceanic intraplate earthquakes are generally reliable indicators of the state of stress in the source region most oceanic intraplate seismicity occurs in young lithosphere

on the origin of the cocos nazca spreading center to investigate the mechanism underlying the break up of the farallon plate into the cocos plate and nazca plate we analyze the state of stress in the farallon plate at about 30 m y b p just prior to the fragmentation to this purpose we use finite element methods and a reconstruction of regional plate boundaries appropriate for 30 m y b p a key role in the model is played by the dependence of two important plate tectonics forces slab pull and ridge push on the age of oceanic lithosphere the results show a highly tensional stress field with maximum principal stresses of 5 to 6 kbar north south tension in the vicinity of present day panama is proposed to have been the cause for the fragmentation of the farallon plate and the inception of spreading along the new cocos nazca plate boundary because the kind of plate interaction that gave rise to the high level of tensional stresses in the farallon plate is not restricted to the area of this study the proposed mechanism seems to shed light on the problem of fragmentation of oceanic plates in general

an outline of neotectonic structures and morphotectonics of the western and central pannonian basin abstract neotectonic deformation in the western and central part of the pannonian basin was investigated by means of surface and subsurface structural analyses and geomorphologic observations the applied methodology includes the study of outcrops industrial seismic profiles digital elevation models topographic maps and borehole data observations suggest that most of the neotectonic structures in the pannonian basin are related to the inverse reactivation of earlier faults formed mainly during the miocene syn and post rift phases typical structures are folds blind reverse faults and transpressional strike slip faults although normal or oblique normal faults are also present these structures significantly controlled the evolution of landforms and the drainage pattern by inducing surface upwarping and river deflections our analyses do not support the postulated tectonic origin of some landforms particularly that of the radial valley system in the western pannonian basin the most important neotectonic strike slip faults are trending to east northeast and have dextral to sinistral kinematics in the south western and central eastern part of the studied area respectively the suggested along strike change of kinematics within the same shear zones is in agreement with the fan shaped recent stress trajectories and with the present day motion of crustal blocks derived from gps data

stable isotope data from loess malacofauna evidence for climate changes in the pannonian basin during the late pleistocene abstract loess is terrestrial clastic sediment composed dominantly of silt sized particles formed by the accumulation of wind blown dust it is usually inter bedded with palaeosol horizons forming loess palaeosol successions lps due to its characteristics loess represents a high quality record of climate changes in the late pleistocene the thickest and best studied loess sections in the republic of croatia are located in the eastern croatian province of baranja near the danube river this area is a southern part of the pannonian basin zmajevas lps was selected in this study grain size distribution indicates that the loess from zmajevac lps in baranja is typical loess comparable with other loess profiles in the pannonian basin the faunal assemblages in the loess samples prove the dominance of transitional palaeoecological assemblage types whereas uniformly defined types are rare helicopsis striata assemblage is dominant while columella columella and chondrula tridens assemblages are present in smaller proportion for additional information about palaeoclimate and palaeoecology in pannonian basin stable oxygen and carbon isotope ratios were measured in mollusc shells stable oxygen values range from 5 76 to 2 45 stable carbon isotope values range from 8 83 to 6 84 stable oxygen values show significant palaeotemperature changes during the late pleistocene with the average growing season ags temperature range of 13 24 c or 9 457 c depending on which formula is applied the overall climate was much cooler then present stable carbon isotope values point to dominance of c3 vegetation type during the late pleistocene in southern part of the pannonian basin

implications of oceanic intraplate seismicity for plate stresses driving forces and rheology abstract recent studies of earthquakes occurring within the oceanic lithosphere provide valuable information about stresses in the lithosphere plate tectonic driving forces and the rheology of the lithosphere asthenosphere and mantle focal mechanisms indicate that oceanic lithosphere older than 35 million years is almost entirely in deviatoric compression both compressional and extensional events occur in younger lithosphere in young lithosphere mechanisms generally indicate compressive stress in the spreading direction or extension oblique to the spreading direction extension in the spreading direction is not observed using the constraint of compression in the spreading direction in old lithosphere models of the stresses produced by a combination of ridge push and basal drag forces require the magnitude of the drag be less than a few bars for rapidly moving plates and a few tens of bars for slow moving plates assuming that basal drag results from mantle return flow the upper limits on drag can be converted to constraints on the viscosity structure of the asthenosphere and mantle using simple two dimensional models if return flow occurs in a mantle of viscosity 10 22 poise comparable to the results from glacial rebound studies the predicted basal drag is too high unless a thin asthenosphere with viscosity less than 10 19 to 10 20 poise depending on flow depth is present the intraplate stress data thus are consistent with the idea of oceanic plates largely decoupled from the underlying mantle the strength of the lithosphere is constrained by the maximum depth of oceanic intraplate seismicity which increases with lithospheric age and appears to be bounded by a 700 800 c isotherm this limiting depth is approximately equal to the flexural elastic thickness of the lithosphere and is consistent with experimental olivine rheologies which predict rapid weakening at high temperatures similar phenomena are important for estimating the fraction of seismic and aseismic slip on transform faults and in determining the extent of rupture for large trench normal faulting events

can the snowline be used as an indicator of the equilibrium line and mass balance for glaciers in the outer tropics because the glacier snowline is easy to identify on optical satellite images and because in certain conditions it can be used as an indicator of the equilibrium line it may be a relevant parameter for the study of the relationships between climate and glaciers although several studies have shown that the snowline altitude sla at the end of the hydrological year is a good indicator of the equilibrium line altitude ela for mid latitude glaciers such a relationship remains conjectural for tropical glaciers indeed unlike in mid latitudes tropical climate conditions result in a distinct seasonality of accumulation ablation processes we examine this relationship using direct field ela and mass balance measurements made on glaciar zongo bolivia 168 s and glaciar artesonraju peru 98 s and the sla retrieved from satellite images acquired in the past two decades we show that on glaciers in the outer tropics 1 ablation is reduced during the dry season in austral winter may august the sla does not change much and satellite images acquired between may and august could be used to compute the sla and 2 the highest sla detected on a number of satellite images acquired during the dry season provides a good estimate of the annual ela however as snowfall events can occur during the dry season the sla detected on satellite images tends to underestimate the ela thus we recommend validating the sla computed from satellite images with field data collected on a benchmark glacier before measuring the sla on other glaciers in the same mountain range for which no field data are available this study is a major step towards extending the measurement of glacier parameters ela and mass balance at the scale of a whole mountain range in the outer tropics to better document the relationships between climate and glaciers

field experiments of beach scarp erosion during oblique wave stormy conditions normandy france abstract a field based experimental study of beach scarp morphodynamic evolution was conducted on the shoreface of a macrotidal sandy beach subject to storms combined with spring tide events luc sur mer france both video and in situ measurements on an artificial berm are used to understand beach scarp evolution over one tide during stormy conditions image time stacks are used to analyze the swash action on the beach scarp and topographical data of the scarp are recorded with a terrestrial scanner laser to quantify the morphodynamic response of the beach scarp to wave action this work provides a new and unique dataset about beach scarp changes and berm morphology in particular under rising tide and oblique wind wave conditions during one stormy event the berm was completely destroyed however contrasting alongshore changes were measured during the erosive phase with different crest and foot scarp retreats and eroded volumes between the west and the east side of the berm the beach in front of the scarp also shows a contrasting residual evolution indicating an evident longshore sediment transport on the study area as a consequence of incident oblique wave conditions a strong connection between beach evolution and beach scarp changes is clearly identified the scarp erosion increases on the west side of the berm when the beach level is lowered and reduces when the beach surface rises on the east side the beach slope and foreshore elevation as a result of a longshore sediment transport between east and west profiles influence swash activity overall water depth and swash activity became progressively different along the scarp during the experiment swash measurements indicate that the presence of the beach scarp strongly influences the swash motion at high tide the reflection of the uprush on the scarp front induces a collision between the reflected backwash and the following uprush dynamic these collisions reduce and sometimes stop the motion of the following uprush reducing the incoming swash excursion consequently the scarp presence modifies the swash interaction that normally appears on a planar beach surface with a beach scarp the swash energy level is substantially attenuated and its spectrum is characterized by a large band the number of uprush impacts on the scarp front calculated from video images reaches about 25 per 5 min in spite of the swash energy attenuation due to swash swash interactions these impacts provoke the berm destruction in about two hours however the onshore migration of the swash zone induced by the rising tide appears to be important to explain scarp destruction compensating the attenuated swash activity due to backwash uprush interactions

landscape response to recent tectonic deformation in the sw pannonian basin evidence from dem based morphometric analysis of the bilogora mt area ne croatia abstract bilogora mt area is a transpressional structure located in the ne of croatia linked with the tectonic evolution of the drava depression the structure formed during pliocene and quaternary from the inversion of nw striking drava depression boundary fault which originated as a normal fault and was reactivated as a dextral strike slip fault during pliocene and quaternary time bilogora mt area underwent more than 400 m of differential uplift while still ongoing tectonic deformation is documented by historical and instrumental seismicity 3 5 m l 5 6 in this geomorphic study the recent deformation in the bilogora mt area although obscured by landscape evolution variables was assessed using dem based landscape morphometry and a set of morphometric indexes local relief and slope angle variability distributions were combined with morphometric indexes computed at the scale of the drainage basin we analyzed hypsometric curves with the hypsometric integral hi basin asymmetry af and parameters of longitudinal stream profiles c f c max l l and k sn analyzed morphometric parameters were combined into a cumulative index of relative tectonic activity rta this index summarizes drainage basin response to the possible recent tectonic activity results suggest that most of the tectonic activity is probably located along the ne front of the bilogora mt area in its nw and central part this activity could be likely related to recent tectonic activity along the kalnik mt fault zone and drava depression boundary fault zones respectively a subordinate area characterized by recent tectonic activity could be suggested within the southernmost part of the study area quaternary activity in this area is probably related to ne striking faults in vicinity of the town daruvar that continue towards the northeast into the study area though methodology presented here represents a good identification tool of possible ongoing deformation this study will be followed by detailed fieldwork and paleoseismological investigations at the identified locations

loess is not just the accumulation of dust most regrettably there is much misuse of terminology in connection with the concept of loess and the interpretation of its origin people often speak and write incorrectly about loess accumulation even loess specialists who are aware of the fact that loess as a concept has to satisfy at least 10 criteria loess is not simply dust carried and deposited by wind dust only becomes loess after the passage of a certain amount of time in a given geographical zone i e only through diagenesis in certain ecological environments to state that loess is of aeolian origin is an oversimplification and an incorrect definition because an aeolian origin applies only to the dust from which the loess has been formed we are aware of the fact that airborne dust cannot be transformed into loess in every geographical environment but only under those conditions typical of semi arid grassland or steppe or forested steppe the process primarily occurs where the rate of dust accumulation exceeds sheet wash or weathering soil formation rates if the rate of dust accumulation is less than that of surface erosion or of soil biogenetic processes the dust then develops into soil or through intensive weathering and increased precipitation into loam or clay only part of the aeolian dust transported and deposited in a zone suitable for loess formation remains there permanently and is transformed in situ into loess dust not affected by diagenesis is usually further transported by snowmelt or rainwash and is only transformed into loess after it has been redeposited the loess itself however is easily erodible and its minerals are readily reworked and reaccumulated and given the appropriate conditions it readily undergoes diagenesis again we do not always have sufficient evidence to determine whether a given loess body is of primary or secondary origin traditionally the minerals making up primary loess have been regarded as originating in dust accumulated by aeolian processes secondary loess by contrast is different from typical loess in many ways and it is not unusual to find various loess series in which superimposed dust fractions have been transformed into loess by different processes recently we have observed that the origin of various types of loess is governed by differences in litho ecological conditions rather than by the way in which the mineral material from which the loess is derived dust has been primarily accumulated loessification is therefore determined by environmental conditions

historical seismicity near chagos a complex deformation zone in the equatorial indian ocean abstract over the last twenty years chagos bank has a seismicity rate disproportionate to its supposed intraplate location earthquake relocation also shows a high seismicity rate in pre wwssn time 1912 1963 with seven events located off of the central indian ridge including large events in 1912 m 6 8 and 1944 m 7 2 this study uses the moment variance technique a systematic search for the mechanism which best fits p pp sh love and rayleigh amplitudes to determine the focal mechanisms of two pre wwssn earthquakes a test with a recent event of known mechanism demonstrates that accurate focal parameter determination is possible even when only a few good records are available moment variance analysis shows a thrust faulting mechanism for the 1944 event northeast of chagos bank near the chagos laccadive ridge and a strike slip focal mechanism for a smaller 1957 event west of chagos bank the 1944 event one of the largest oceanic intraplate earthquakes known moment 1 4 1027 dyne cm indicates that the chagos seismicity reflects not an isolated occurrence of normal faulting as previously thought but rather regional tectonic deformation extending northeast of chagos bank and including thrust normal and strike slip events this seismicity and previously studied seismicity near the ninetyeast ridge and central indian basin suggest a broad zone of deformation stretching across the equatorial indian ocean this zone contains all known magnitude seven oceanic intraplate earthquakes not associated with subduction zones or continental margins suggesting that elsewhere such extensive deformation occurs only along plate boundaries this study proposes that a slow diffuse plate boundary extends east from the central indian ridge to the ninetyeast ridge and north to the sumatra trench a recent plate motion study confirms this boundary and suggests that it separates the australian plate from a single indo arabian plate

glacier climate interaction at low latitudes in the low latitudes there is an absence of major thermal seasonality yet there are three different climate regimes related to global circulation patterns and their seasonal oscillation the humid inner tropics the dry subtropics and intermediate between these two the outer tropics for the respective glacier regimes the vertical profiles of specific mass balance vbps are modeled considering vertical gradients of accumulation air temperature and albedo the duration of the ablation period and a factor for the ratio between melting and sublimation the model is first calibrated with data from hintereisferner austrian alps and is then applied to tropical conditions the simulated vbp matches well the measured profiles from irian jaya and mount kenya due to lack of field evidence the subtropical vbp cannot be verified directly however application of the respective model versions separately to the humid and dry seasons of the outer tropical glaciar uruashraju cordillera blanca peru provides reasonable results glaciers in the humid inner tropics are considered to be most sensitive to variations in air temperature while dry subtropical glaciers are most sensitive to changes in air humidity the two seasons of the outer tropics have to be viewed from these different perspectives

the freezing level in the tropical andes peru an indicator for present and future glacier extents along with air temperatures the freezing level height flh has risen over the last decades the mass balance of tropical glaciers in peru is highly sensitive to a rise in the flh mainly due to a decrease in accumulation and increase of energy for ablation caused by reduced albedo knowledge of future changes in the flh is thus crucial to estimating changes in glacier extents since in situ data are scarce at altitudes where glaciers exist above 4800 m above sea level asl reliable flh estimates must be derived from multiple data types here we assessed the flhs and their spatiotemporal variability as well as the related snow rain transition in the two largest glacier covered regions in peru by combining data from two climate reanalysis products tropical rainfall measuring mission trmm precipitation radar bright band data micro rain radar data and meteorological ground station measurements the mean annual flh lies at 4900 and 5010 m asl for the cordillera blanca and vilcanota respectively during the wet season the flh in the cordillera vilcanota lies 150 m higher compared to the cordillera blanca which is in line with the higher glacier terminus elevations coupled model intercomparison project version 5 cmip5 climate model projections reveal that by the end of the 21st century the flh will rise by 230 m 190 m for representative concentration pathway rcp 2 6 and 850 m 390 m for rcp8 5 even under the most optimistic scenario glaciers may continue shrinking considerably assuming a close relation between flh and glacier extents under the most pessimistic scenario glaciers may only remain at the highest summits above approximately 5800 m asl

using fill terraces to understand incision rates and evolution of the colorado river in eastern grand canyon arizona 1 the incision and aggradation of the colorado river in eastern grand canyon through middle to late quaternary time can be traced in detail using well exposed fill terraces dated by a combination of optically stimulated luminescence uranium series and cosmogenic nuclide dating this fluvial history provides the best bedrock incision rate for this important landscape and highlights the complications and advantages of fill terrace records for understanding river long profile evolution and incision the use of fill terraces as distinct from strath terraces for calculating incision rates is complicated by the cyclic alluviation and incision they record in the example of the grand canyon this has led to various rates being reported by different workers and rates that tend to be overestimates in shorter records we illustrate that a meaningful long term bedrock incision rate of 140 m m y can be extracted from the grand canyon record by linking episodes when the colorado river is floored on bedrock variable incision rates reported in the greater region may be to some degree due to inconsistent calculations our data also highlight that the colorado river has been a mixed alluvial bedrock river through both time and space and has been a bedrock river for less than half of its pleistocene history this strong temporal variation combined with the varying bedrock the river encounters on its path heightens the challenge of understanding the tectonic climatic and drainage integration controls on the form and evolution of the colorado river s long profile

earthquake source mechanisms from body waveform inversion and intraplate tectonics in the northern indian ocean double couple point source parameters for 11 of the largest intraplate earthquakes in the northern indian ocean during the last 20 y were determined from a formal inversion of long period p and sh waveforms nine of the events have centroid depths at least 17 km below the seafloor well into the upper mantle two have centroid depths as great as 39 km using the source mechanisms of these earthquakes we distinguish two major intraplate tectonic provinces in the northern indian ocean to the west of the ninetyeast ridge in the southern bay of bengal intraplate earthquakes have thrust faulting mechanisms with p axes oriented n s the centroid depths of these earthquakes range from 27 to 39 km below the seafloor lithospheric shortening in this region is thus accomplished by thrust faulting in the strong core of the oceanic upper mantle while other geophysical evidence suggests that shallow sedimentary and crustal layers apparently deform predominantly by folding in the immediate vicinity of the ninetyeast ridge earthquakes display strike slip mechanisms with left lateral motion on planes parallel to the ridge this type of faulting occurs from at least 10 s to the northern end of the ninetyeast ridge near 10 n where the ridge meets the sunda arc seismic activity diminishes to the east of the ninetyeast ridge but is also characterized by strike slip faulting despite these variations in deformational style the inferred orientation of greatest compressive stress in the northern indian ocean displays a consistent long wavelength pattern over a large portion of the indian plate varying smoothly from nearly n s in the bay of bengal to nw se in the northeastern indian ocean this plate wide stress pattern and the high level of intraplate seismicity in the northern indian ocean are likely the results of substantial resistance along the himalayan continental collision zone to the continued northward motion of the western portion of the indian plate oceanic intraplate earthquakes in other regions where the level of deviatoric stress associated with the long wavelength part of the stress field is likely to be smaller need not be comparably reliable indicators of the plate wide stress field

seismicity and earthquake focal mechanisms in north western croatia article i nfo the seismicity of nw croatia seismically the most vulnerable part of the country is presented based on historical records and reanalysed and relocated earthquakes occurring after 1908 the improved picture of the distribution of seismicity shows consistent grouping of foci in space mostly within eight epicentral areas the database of fault plane solutions has been considerably enlarged and now lists 22 earthquakes the earthquake mechanisms consistently reveal the subhorizontal to moderately dipping p axis predominantly n s directed in the central part of studied area to nw se and ne sw directed in the western and eastern parts respectively they indicate the prevalence of compressional tectonics with reverse faulting in the central part versus strike slip motions in the western and eastern sectors these data are in agreement with stress calculations and kinematics of quaternary structures obtained by geological studies the completeness of the catalogue estimated by comparing the cumulative activity rate for a large number of subcatalogues to the reference contemporary rate exhibits large spatial heterogeneity taking this into account we have computed and mapped the parameters of the frequency magnitude recurrence relation the b value and the activity rate

rates of river incision across the main tectonic units of the pamir identified using optically stimulated luminescence dating of fluvial terraces calculated incision rates along the panj the main river of the pamir are used to investigate any influence by tectonics or climate on the architecture of the river the depositional ages of panj river terraces were calculated using optically stimulated luminescence osl dating of terrace sand fluvial incision rates were generated by integrating the terrace depositional ages with accurate kinematic gps measurements of terrace heights above the modern panj we investigated 16 terraces along the panj at the western pamir margin and one terrace from the vakhsh river to the north of the pamir the results reveal brief periods of fluvial deposition over the past 26 kyr the oldest panj terrace depositional ages coincide with early mis 2 and mis 2 1 glaciations on the pamir plateau younger terrace ages have no apparent link with glacial cycles terraces with varying heights above the modern panj at different localities yielded similar depositional ages this suggests that local conditions have determined fluvial incision rates combining all of the terrace measurements the average incision rate of the panj over the last 26 kyr has been 5 6 mm yr a high mean incision rate of 7 3 mm yr was calculated from terraces where the panj has cut a steep sided valley through the shakhdara dome significantly lower incision rates 2 3 mm yr were calculated from terraces where the panj flows along the southern boundaries of the shakhdara and yazgulom domes at those localities graded segments of the panj river profile and increased valley widths are indicative of local base levels downstream of the yazgulom dome river incision rates are generally lower 4 5 mm yr than the panj average however there is one exception where higher incision rates 6 mm yr were calculated upstream of the darvaz fault zone a major tectonic feature that forms the western boundary of the pamir the vakhsh river terrace to the north of the pamir yielded a lower incision rate 3 mm yr compared to the panj average variation in incision rates along the panj does not correspond to changes in rock type or river catchment area instead incision rates appear to have been primarily influenced by river capture across the southern and central metamorphic domes of the pamir wherever the panj cuts these domes it displays a convex river profile the combination of localized river profile convexity and changes in incision rates across the pamir domes indicates that the dome boundaries have been active recently

model study of the spatial distribution of the energy and mass balance of morteratschgletscher switzerland to investigate the spatial distribution of the energy and mass balance fluxes of a glacier a two dimensional mass balance model was developed and applied to morteratschgletscher switzerland the model is driven by meteorological input from four synoptic weather stations located in the vicinity of morteratschgletscher the model results were compared to observations made on the glacier the calculated mean specific mass balance is 0 47 m w e for 1999 and 0 23 m w e for 2000 net shortwave radiation shows a minimum at around 3350 m a s l due to the effects of shading slope aspect reflection from the slopes and obstruction of the sky ignoring these effects results in a 37 increase in the annual incoming shortwave radiation on the glacier causing 0 34 m w e more ablation a 1 c change in the air temperature results in a shift of 0 67 m w e in the mean specific mass balance while altering the precipitation by 10 causes a change of 0 17 m w e

accretion and lateral variations in tectonic structure along the peru chile trench abstract extensive marine geophysical data sets on the deformational characteristics of the oceanic crust and of sediments in and near the peru chile trench notably those presented by schweller kulm and co workers have established the presence of significant north south variations along the trench in this paper we investigate the physical basis for these variations by studying the stress field in the nazca plate with emphasis on the region near the trench finite element methods were employed to calculate the stress distribution the resulting regional stress field near the trench is characterized by compression normal to the trench at latitudes between 1 s and approximately 16 s tension in the range 16 s 27 s and again compression from 27 s to 45 s many conspicuous and hitherto unexplained variations along the trench system can be understood by taking into account these lateral changes a close correlation appears to exist between the latitude ranges with compression and tension normal to the trench and the accreting and non accreting provinces of the peru chile trench respectively the basis for this correlation must be sought in the role which grabens in the seaward trench slope play in the subduction or accretion of sediments deep grabens can trap the sediments and carry them down into the subduction zone leaving little or no material to be accreted onto the margin the regional stress field is superimposed on the stresses generated in bending the nazca plate prior to subduction tension in the direction normal to the trench as inferred for the nazca plate off southern peru and northern chile 16 s 27 s lowers the neutral plane in the bending plate and increases the tensional stresses near the surface this promotes the formation of grabens and consequently the subduction of sediments similarly compression normal to the trench counteracts the formation of deep grabens in the latitude ranges 1 s 16 s and 27 s 45 s thus favouring accretion of sediments from this study we infer that the regional stress field may have a significant effect on the topography of the seaward trench slope taking into account the role of regional stress in graben formation not only explains first order latitudinal variations in accretion and subduction of sediments along the peru chile trench but it is also expected to contribute significantly to understanding similar variations observed in other subduction zones

luminescence dating of the stratzing loess profile austria testing the potential of an elevated temperature post ir irsl protocol abstract feldspar infrared stimulated luminescence irsl signals saturate at 2000 gy i e 500 700 ka assuming a dose rate of 3 4 gy ka typical for loess and it is therefore theoretically possible to date middle pleistocene loess however the accuracy of age estimates is hampered by anomalous fading which leads to significant age underestimation fading corrections have been proposed but these corrections are reliant on inherent assumptions and in any case are inapplicable at large doses as the growth curve approaches saturation recent studies have identified a post ir irsl signal that shows less fading and is thus less dependent on accurate fading corrections this study builds upon these investigations and applies a post ir irsl sar dating protocol to polymineral fine grain samples of the loess palaeosol sequence in stratzing lower austria after a preheat at 320 c 60 s and an ir bleach at 50 c 200 s irsl was measured at 290 c for 200 s the same set of conditions were used to measure the response to a test dose recycling ratios recuperation and dose recovery tests show that this protocol is suitable for the loess under investigation although finite residual doses of up to 20 gy are observed for the oldest samples the natural signal is in or close to saturation indicating that fading is negligible in nature this observation is inconsistent with the measured laboratory fading rates of 1 1 5 decade and needs further investigation

70 years of lake evolution and glacial lake outburst floods in the cordillera blanca peru and implications for the future climate change glacier retreat and glacial lake outburst floods glofs are intertwined the cordillera blanca in peru has one of the world s longest glof records and here we assess the evolution of glacial lakes in the region between 1948 and 2017 and investigate the links to documented glofs we also model future lake evolution under two climate scenarios to provide an assessment of current and future glof triggering potential our analysis shows that the number of lakes as well as the total lake area has increased during the historical period the formation of new lakes is however not uniform among different lake types with bedrock dammed lakes exhibiting the largest increase in recent decades we argue that moraine dammed lakes have already formed at the majority of potential locations in the cordillera blanca and that the next generation of lakes which are expected to form in response to glacier retreat over topographically suitable areas will be predominantly bedrock dammed based on a regional glof inventory we show that the peak frequency of glofs occurred from the late 1930s to early 1950s while glofs originating from moraine dammed lakes dominated in this period recent glofs have originated from bedrock dammed lakes at the same time the majority of glofs originated from lakes in a proglacial phase i e in contact with glacier even though the share of proglacial lakes did not exceed 12 at any time step during the analysed period while many moraine dammed lakes evolved into the glacier detached evolutionary phase bedrock dammed lakes became a major lake dam type among proglacial lakes over the remainder of the 21st century a further increase in lake area of up to 10 is anticipated with up to 50 new bedrock dammed lakes likely to develop as glaciers retreat there is little difference in lake development and glof triggering potential under climate scenarios driven by rcp 2 6 and 8 5 based on topographic disposition recent and future lakes do not individually appear more or less susceptible to landslide impact than lakes that already developed earlier in the 20th century synthesizing these findings we forecast that bedrock dammed lakes will become the dominant source of glofs in the next decades because such dams are inherently more stable we expect overall lower glof magnitudes compared to documented glofs from moraine dammed lakes

stress in the indo australian plate cloetingh s and wortel r 1986 stress in the ind austr ian plate in b johnson and a w bally editors intraplate deformation characteristics processes and causes tectonophysics 132 49 67 we modelled the state of stress in the indo australian plate in order to investigate quantitatively variations observed in tectonic style the numerical procedure incorporates the dependence of slab pull and ridge push on the age of the oceanic lithosphere estimates are presented for the average net resistive forces at the himalayan collision zone the suction force acting on the overriding indo australian plate segment at the tonga kermadec trench and the drag at the base of the lithosphere our modelhng shows a concen ation of compressive stresses of the order of 3 5 lcbar in the ninetyeast ridge area the effects of the compressive resistance associated with himalayan collision and subduction of young lithosphere off the northern part of the sunda arc are focused in this region the stress field as calculated gives a consistent explanation for the observed concentration of seismic activity stein and okal 1978 and significant deformation in the oceanic crust weissel et al 1980 mcadoo and sandwell 1985 in the area the calculated stress field in the area adjacent to the southeast and central india ridges is characterized by tension parallel to the spreading axis this explains the concentration of near ridge normal faulting seismicity with t axes subparaile1 to the spreading ridge in the indian ocean as recently observed by bergman et al 1984 and wiens and stein 1984 the regional stress field along the strike of the sunda arc varies from compression seaward of and parallel to the sumatra trench segment to tension perpendicular to the java flores segment this explains the selective occurrence of well developed grabens seaward off the java flores segment of the trench observed by hilde 1983 our modelling shows that the observed rotation of the stress field denham et al 1979 in the australian continent is mainly the consequence of its geographic position relative to the surrounding trench segments and the variations of the forces acting on the down going slab in each of these the state of compression in west and central australia is induced by the action of resistive forces at the himalayan and banda arc collision zones the joint occurrence of high levels of compression in the plate s interior and normal faulting seismicity in the near ridge areas is a transient feature unique to the present dynamic situation of the indo australian plate

thermoelastic stress how important as a cause of earthquakes in young oceanic lithosphere we present a series of exploratory models which test the hypothesis that thermoelastic stress is a significant contributor to the state of stress in young oceanic lithosphere less than 35 m y in age in support of this hypothesis is the concentration of seismicity in lithosphere younger than 15 m y where cooling rates are relatively high most near ridge earthquakes have focal depths between the moho and the depth of the 800 c isotherm thrust and strike slip events dominate the shallowest seismicity while the focal mechanisms of the deeper events are generally characterized by normal faulting to assess the importance of thermal stress in the generation of near ridge earthquakes we model the lithosphere as an elastic half space in which the response to cooling is computed using the method of thermoelastic displacement potentials a key assumption in the models is that stress is relieved on time scales generally short compared with the age of the lithosphere a further assumption in some models is that material will not contribute thermal stress until it has cooled below an elastic blocking temperature normal faulting is predicted throughout the lithosphere in thermal stress models based on simple half space cooling models in which a cooled surface layer is incorporated to simulate the effect of hydrothermal circulation on shallow thermal structure predict stresses that can match the locations of both thrust and normal faulting earthquakes near mid ocean ridges the addition of a ridge push stress to the computed thermal stress enhances the likelihood of thrust faulting in the uppermost lithosphere at ages greater than about 15 m y but probably contributes little to the stress field at younger ages though these simple models are limited by several simplifying assumptions particularly in the immediate vicinity of the ridge axis they support the hypothesis that thermoelastic stress can play a major role in the tectonics of young oceanic lithosphere

evaluation of recent glacier recession in the cordillera blanca peru ad 1962 1999 spatial distribution of mass loss and climatic forcing we use a combination of aerial photogrammetry satellite imagery andd ifferential gps mapping to quantify the volume of ice lost between ad 1962 and 1999 from three glaciers on nevado queshque in the cordillera blanca peru 101s the largest averagedsurface lowering thinning occurredin the southwest aspect 22 m andthe least in the eastern aspect 5 m a heuristic sensitivity analysis indicates that 9 3 w m 2 was requiredto melt the total observedice loss andthis can be explainedby sensible heat transfer relatedto a temperature rise of 1 1c combinedwith a latent heat d ecrease relatedto a 0 14 g kg 1 increase in specific humidity a first difference analysis of temperature records from 29 stations in the cordillera blanca shows an average rising trend of 0 261c per decade over the 37 year interval more than adequate to supply the hypothesized sensible heat transfer a simple transmittivity model within a digital elevation model indicates solar radiation related to altered cloudiness was not a predominant climatic forcing the distribution of glacier area with altitude calculated with the digital terrain model explains the observed asymmetrical ice melt r 2005 elsevier ltd all rights reserved

tectonic activity in the croatian part of the pannonian basin abstract three main stages in structural development of the sw pannonian basin are differentiated the onset of extensional tectonics between the oligocene and the early miocene main extensional processes in the early and middle miocene and prevailing transpression in the pliocene and quaternary the neotectonic phase is given special attention in this paper structural fabrics allow to subdivide the area into three large structural zones corresponding to the western southern and central marginal part of the pannonian basin in croatia these zones are bounded by important faults the periadriatic drava fault the medvednica fault zone and the southern marginal fault of the pannonian basin the recent displacements within the dinarides and the eastern alps form the boundary conditions for active transpressional deformation in the western marginal part of the pannonian basin dextral transcurrent displacement is evident in the zone of the periadriatic drava wrench fault the formation of the new types of structures is observed especially in zones of compression along the faults narrowing of the area between the sava and drava rivers causes structural changes in the marginal parts of the corresponding basins i e in the areas close to the slavonian mts recent tectonic activity is marked by the occurrence of earthquakes which are most common in the northwestern part of croatia the spatial distribution of hypocentres and of seismotectonically active zones is used to reconstruct probable displacements and the structural style of deformation in depth the earthquake sources in the vicinity of the medvednica fault and the periadriatic drava fault are given special attention

luminescence dating of late holocene dunes showing remnants of early settlement in cuddalore and evidence of monsoon activity in south east india abstract in this study dunes from south east india were dated using optically stimulated luminescence osl to reconstruct the depositional history a belt of dunes has developed parallel to the coast between pondicherry and karikal in tamil nadu south east india in the area between cuddalore and porto novo the dune belt is 5 km wide a transect from the coast to the most western dune inland was investigated changes in the environmental conditions are recorded in the dunes they show features including unconformities changes in the direction of bedding erosional features water escape structures and remnants of human settlements the osl results show that strong changes in the environmental conditions occurred about 100 and 300 years ago the latter event marks also the termination of settlement in this place the settlement period started about 1500 years previously the periods of sand mobility and stabilisation of the land surface by soil formation correlate with changes in the precipitation record of india the investigated dunes very likely reflect fluctuations in the monsoon activity during the last 3500 years in south east india

tropical glacier meltwater contribution to stream discharge a case study in the cordillera blanca peru original abstract discharge measurements climate observations and hydrochemical samples gathered monthly 1998 99 in the yanamarey and uruashraju glacier fed catchments of the cordillera blanca peru permit an analysis of the glacier meltwater contribution to stream flow these glacier catchments feed the rio santa which discharges into the pacific ocean based on a water balance computation glacier melt contributes an estimated 35 of the average discharge from the catchments for comparison a volumetric end member mixing model of oxygen isotopes shows glacier melt contributes 30 45 to the total annual discharge based on stream geochemistry discharge from the yanamarey glacier catchment provides 30 of the annual volume discharged from the querococha watershed which is 10 glacierized by analogy the larger rio santa watershed also 10 glacierized receives at least 12 of its annual discharge from melting glacier ice tributary watersheds to the rio santa with larger fractions of glacier cover have less variable runoff and enhanced discharge demonstrating that the glaciers effectively buffer stream discharge seasonally with continued glacier melting stream flow will likely become more variable and there will be less dry season runoff

tracing the origin of loess in hungary with the help of heavy mineral composition data abstract heavy mineral composition of the fine sand fraction in the hungarian loess sediments provides important data about the closer sources of the loess in the carpathian basin quantitative detrital heavy mineral compositions of 216 loess loess like sediment and paleosol samples were compared to each other and to recent fluvial sands and different cenozoic sands and sandstones of hungary using statistical methods cluster analysis principal component analysis and discriminant analysis usually garnet is the most frequent detrital heavy mineral in the studied loess sections followed by chlorite magnetite epidote and amphiboles old loess and young loess have similar compositions indicating uniform or similar sources based on the similarities the garnet rich loess sediments could originate from aeolian reworking of the floodplain sediments of the danube and other rivers of transdanubia and the local cenozoic sands of the uplifting transdanubian central range and transdanubian hilly region the biotite and tourmaline rich loess in south transdanubia and the loess with high pyroxene content in the north hungarian range had some material from nearby sources weathered granitoids and volcanic rocks respectively or sediments of local rivers which carried detritus of these rocks the new results presented in this paper confirm numerous earlier ideas about the origin of loess in the carpathian basin but also suggest newly identified sources of the loess particles at several locations

phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration abstract progress in understanding the structural evolution of the pannonian basin is reported this has been driven by the application of seismic stratigraphy constrained by magnetostratigraphic data and the recent release of a great amount of hydrocarbon exploration data this has led to a redefinition and better understanding of the syn rift period and style of rifting in addition a complex structural evolution history during the post rift phase has been recognized two compressive events are defined one in the early stage and another in the late stage of evolution the importance of these findings for hydrocarbon exploration includes an improved knowledge of the timing of trap formations and a possible explanation for remarkably variable reservoir pressures in pools of the great hungarian plain

tectonic implications of the gps velocity field in the northern adriatic region 1 continuous and episodic gps observations between 1991 and 2004 show that adria moves independently of both stable eurasia and nubia adria moves nne at 3 4 5 mm yr increasing from n to s relative to eurasia and may be fragmenting along the gargano dubrovnik seismic zone the observed 2 3 mm yr of n s adria eurasia convergence is taken up by contraction across a narrow 70 km zone in the eastern alps and concomitant extrusion of the alpine north pannonian unit the adria central dinarides boundary is a broader collisional zone with intense 1 1 5 mm yr shortening near shore and 2 mm yr spread across the dinarides the remaining 1 2 mm yr motion e of the alps and ne of the dinarides is absorbed by the inverted contracting pannonian basin leaving no significant deformation above 0 5 mm yr in the western and northern carpathians and european platform

diagnosing the imbalance of glaciar santa rosa cordillera raura peru for glaciar santa rosa in the cordillera raura peru the extent and volume are determined for 1980 and 1961 from topographic mapping and for two undated earlier stages lme and max from moraines the regime of the glacier in terms of ice flow and mass balance is evaluated for the 1977 83 period more than half of the water discharge from the glacier is not renewed by precipitation but supplied by the ice thinning the rate of surface lowering of 2 m a 1 liquid water equivalent corresponds to an energy amount for melting of 22 w m 2 sensitivity analyses of glaciar yanamarey in the nearby cordillera blanca show that such a decrease of energy available for melting could be produced by a cloudiness increase of one tenth an air temperature decrease of more than 2 c a decrease in specific humidity of 1 g kg 1 or some combination of heat budget processes such changes in the atmospheric environment would be required to stabilize the glacier at its recent volume as another indication of the recent imbalance the maximum volume flux is found about 100 m below the equilibrium line altitude under continuation of recent climatic conditions the glacier may disappear within a few decades these inferences corroborate a recent assessment for the neighboring cordillera blanca

correlation of loess paleosol sequences in east and central asia with se central europe towards a continental quaternary pedostratigraphy and paleoclimatic history abstract as recent small climatic fluctuations on a 102 103 year time scale can be correlated worldwide and represent a decline of mean annual temperature of only 1 c major climatic changes on at least a 105 year scale glacial interglacial cycles and probably a 104 year scale the approximate length of an interglacial must be of similar ages throughout the temperate climatic belt of the northern hemisphere this concept allows continental pedostratigraphical correlations detailed knowledge of the genesis of paleosols is needed to establish loess paleosol stratigraphies that can be used for paleoclimatic reconstruction most paleosols however are truncated and largely recalcified from overlying loess micromorphological studies allow primary and secondary carbonates to be distinguished and provide unequivocal evidence of clay illuviation this enables the recognition of typical loess weathered loess and the recognition of different genetic soil horizons such as cb bc ah bw and bt horizons for the brunhes epoch the sequence at karamaydan tadjikistan is more detailed than the corresponding section in luochuan china and even more than in se central europe except for the last glaciation the very good correlation with the deep sea oxygen isotope record which includes the development of an accurate astronomical time scale allows a detailed chronostratigraphical subdivision of the loess paleosol sequence in karamaydan which therefore should be regarded as a key sequence for reconstructing the climatic history of the brunhes epoch this implies that the loess paleosol sequences in se central europe are less complete than thought earlier pedocomplexes in karamaydan correspond with single paleosols in se central europe e g the f6 paleosol in stari slankamen correlates with pedocomplexes pk vi and v at karamaydan which were formed over a period of about 140 ka although pedogenesis was interrupted several times by loess deposition the f6 soil is therefore an example of a welded paleosol as are the f5 the f4 and the f2 paleosols in se central europe for most of the matuyama epoch the central and lower parts of the sequence at chashmanigar show more pronounced paleosols than the equivalent parts at luochuan in se central europe only at stari slankamen are three strongly developed though truncated paleosols f9 f11 above neogene sediments mineralogical investigations of the silt and clay subfractions show that there is little difference in the type and amount of pedogenic clay mineral formation between the holocene soils and the paleosols of the brunhes epoch at karamaydan and of the matuyama epoch at chashmanigar this suggests that the interglacial climates represented by the b or bt horizons of the buried paleosols of late middle and early pleistocene age were similar to that of the holocene

thermal stress and the spacings of transform faults bathymetric charts are used with satellite altimeter profiles to locate major ridge transform intersections along five spreading ridges the ridges are the mid atlantic ridge the east pacific rise the chile rise the pacific antarctic rise and the southeast indian ridge analysis of these data show spacings between transform faults w increase linearly with spreading rate w 6 28 m y this linear correlation is explained by a thermoelastic model of a cooling strip of lithosphere spreading at a rate the traction free boundaries of the thin elastic strip simulate cracks in the lithosphere at transform faults a two dimensional thermoelastic solution for the in plane stress shows the largest stress component is tensional and parallel to the ridge stresses are zero at the ridge and increase as age to a maximum value at an age of w 4 all stress components are small for ages greater than w when the transform spacing is large compared with the spreading rate w 100 m y thermal stresses exceed the strength of the lithosphere for ages between 0 and 30 ma the observed maximum ratio of transform spacing to spreading rate w 10 m y results in low thermal stresses that only exceed the strength of the lithosphere for ages less than 1 ma thus transform faults relieve most of the thermal stress model predictions also agree with earthquake studies showing that normal faults in young lithosphere have tensional axes aligned with the ridge moreover oceanic intraplate earthquakes rarely occur in lithosphere older than 30 ma as predicted by the model these and other geophysical observations confirm turcotte s hypothesis that transform faults are thermal contraction cracks

heat transfer and intraplate deformation in the central indian ocean nineteen new heat flow measurements made across deformed oceanic lithosphere in the central indian ocean and previously published data show that heat flow is significantly higher than predicted by models for cooling oceanic lithosphere over much of the region many of the temperature depth profiles are nonlinear upward convection of water is the most likely explanation for the curvature of the temperature profiles since other possible causes including variations in bottom water temperatures conductivity changes with depth in the sediments and experimental error can be eliminated this interpretation requires water velocities of the order of 7 x 10 sup 8 m s which is unusual because the lithosphere is relatively old 72 82 m y and a thick sedimentary cover 1 2 5 km is present these observations suggest that the processes causing deformation of the plate have increased the heat flux through the sediment water interface we infer that extra heat is being generated at shallow depths perhaps less than 35 km in the plate although the specific mechanism by which deformational energy is converted into heat is difficult to determine

first post ir irsl dating results of quaternary deposits from bilogora ne croatia implications for the pleistocene relative uplift and incision rates in the area abstract bilogora is a hilly terrain in the sw pannonian basin along the sw margin of the drava depression in croatia it is genetically linked to the tectonic evolution of the drava depression during the neogene and quaternary and the associated palaeo drava river system the quaternary sedimentary succession is represented by four aggradational drava river terraces composed of thick series of gravel intercalated by sand silt and clays stratigraphically the oldest terraces exposed in the investigated area are unconformably overlain by pleistocene loess and loess like deposits in order to establish a chronological framework of the quaternary deposits luminescence dating was applied on loess and loess like sediments as well as sand intercalated within the terrace gravel deposits the dating was performed on feldspar coarse grains from the sand and on the polymineral fine grained material from loess using the pirir 290 protocol the luminescence signals of the sand are in saturation and therefore very likely point to a middle pleistocene age of the river terrace whereas the covering loess can be correlated to the last glacial the obtained pirir 290 dating results indicate the timing of the abandonment of the investigated river terrace whereas the relation of the relative displacement values of the investigated river terrace to the obtained age could imply the relative uplift rates of the area according to the relative displacement values sampling heights above the present drava river level and the obtained pirir 290 ages of 359 ka and 450 ka the calculated relative uplift rates were 0 56 mm a for mucna reka and 0 43 mm a for cabuna for the same sampling locations the calculated relative incision rates of the drava river were of 0 09 and 0 22 mm a the results of relative uplift rates show a higher value concentrated in the nw part of bilogora being associated with multiple mapped neotectonic active faults in the drava depression boundary fault zone and kalnik mt fault zone on the other hand the low incision rates that probably accommodate a portion of the tectonic uplift of bilogora point to lower erosion of the paleo drava river moreover the drava river is dominated by the aggradation of alluvial deposits during the quaternary we believe that the computed incision rates represent only one relative portion of the drava process whereas the tectonics sediment transportation and accumulation were dominant processes in the study area and can be correlated with the climate oscillations during the pleistocene and holocene

tectonic stresses in the lithosphere various types of observables earthquake focal mechanisms in situ measurements and geological deformations give information about the large scale lithospheric stress field the latter has often been explained by postulating appropriate forces acting at the edges and beneath the plates this approach ignores the role of mass heterogeneities within the lithosphere here we analyze the effect of both boundary and internal forces on the stress pattern and show that both contributions are of comparable magnitude the presence of internal sources makes the problem three dimensional we show however that it can be reduced to a two dimensional plane stress formulation whereby the edge forces are expressed by the non hydrostatic stresses and the basal shear is increased by the addition of a term proportional to the gradient of the mean vertical stress for the oceanic lithosphere we derive a compression that increases with age the comparison with geophysical observables yields an upper bound of a few bars on the magniude of the basal drag for the continents we infer the existence of an underlying upper mantle somewhat denser than under oceans

the mid hungarian line a zone of repeated tectonic inversions abstract the mid hungarian line is a major tectonic feature of the intra carpathian area separating two terranes of different origin and tectonic structure although this tectonic line was known from borehole records it has not been described in seismic sections the study presents interpreted seismic lines crossing the supposed trace of the mid hungarian line these seismic sections show north dipping normal faults and thrust faults as well as cross cutting young strike slip faults a complex tectonic history is deduced including intra oligocene early miocene thrusting middle miocene extension local late miocene inversion and late miocene pliocene normal faulting and left lateral wrenching in the light of our seismic study we think that the best candidate for the mid hungarian line is a north dipping detachment fault beneath large masses of neogene volcanics the auxiliary structures to the north seen on seismic sections suggest that it moved as a south vergent thrust fault during the palaeogene early miocene which later was reactivated as a set of normal faults the northern alcapa unit overrode the southern tisza dacia unit along this fault zone the same relative positions are observed in the northern termination of the line other structures along the supposed trace of the line are north dipping normal or strike slip faults which frequently were reactivated as smaller thrust faults during the late neogene palaeogene early miocene thrusting along the line might be the result of the opposite tertiary rotations of the two major units as suggested by palaeomagnetic measurements and earlier models

revisiting the loess palaeosol sequence in paks hungary a post ir irsl based chronology for the young loess series in hungary many loess palaeosol sequences have been found to be discontinuous in order to allow for correlations with other quaternary records reliable chronologies are needed we therefore apply post ir infrared ir stimulated luminescence post ir irsl pirir290 dating to the uppermost 20 m of the loess sequence at paks the pirir290 ages are compared with blue quartz osl ages to test for potential age overestimation due to poor signal re setting and the observed good agreement is taken to imply that the more difficult to bleach pirir290 signal was reset prior to deposition our pirir290 based chronology reveals that most of the late pleistocene loess was deposited during marine isotope stage mis 3 and during the last glacial maximum lgm this is in disagreement with formerly published ages the discrepancy can most likely be explained by anomalous fading resulting in an age underestimate this conclusion is supported by our uncorrected standard irsl ages we further confirm that the basaharc double soil complex can be correlated with mis 7 the underlying loess and soils cannot be dated accurately because the pirir290 signal approaches saturation

age dependence of oceanic intraplate seismicity and implications for lithospheric evolution we have determined depths for 16 oceanic intraplate earthquakes using body wave modeling a data set composed of these and 11 other well constrained depths shows that the maximum depth of seismicity deepens with increasing lithospheric age and appears to be bounded by a 700 800 c isotherm the maximum depth to which intraplate earthquakes occur is approximately equal to the flexural elastic thickness but much less than the seismic thickness from surface wave dispersion the maximum faulting depth is consistent with the predictions of rapid weakening at high temperatures for dry olivine rheologies determined by experimental rock mechanics oceanic intraplate earthquakes can occur at greater depths and temperatures than has previously been reported for continental crustal events presumably because oceanic lithosphere is stronger at high temperatures both the number of earthquakes and the cumulative seismic moment decrease with lithospheric age the cause of this trend is unclear possibilities include nonrandom location of preexisting weak zones with respect to the age provinces fault strengthening with age or a decrease in the stress level a decrease in intraplate stress with age is opposite that expected from ridge push stresses which increase with age but may result either from thermoelastic stresses which are greatest in young lithosphere or near ridge stress concentrations due to local heterogeneities in the spreading process

fluvial terrace formation in the eastern fenwei basin china during the past 1 2 ma as a combined archive of tectonics and climate change abstract the key to understanding the fluvial response to climate change and surface uplift is a thorough distinguishing between their roles in terrace formation previous studies have tended to attribute the fluvial behavior of deposit incision alternation to climate cyclicity a preliminary explanation is proposed here for terrace formation in the eastern part of the fenwei basin china the observed fluvial terrace sequence was developed by the yellow river deeply downcutting into the emei platform which was uplifted within the eastern fenwei basin and therefore it probably records the tectonic history of this platform on the basis of the magnetostratigraphy and optically stimulated luminescence osl dating a ca 1 2 ma chronology was established for this terrace sequence pedostratigraphic analysis of the loess deposits accumulated on each tread reveals that the terrace deposits are overlain immediately by a paleosol bed suggesting that the abandonment of these terraces due to fluvial incision occurred at the transitions from glacial to interglacial climates the glacial interglacial climate cycle probably has a temporal control on the fluvial behavior of deposit incision alternation even though the yellow river develops in the subsiding fenwei basin the terrace generation may be sporadic and in the form of unusual stacked pattern before the emei platform was uplifted within the eastern fenwei basin the terrace staircases however formed in synchrony with glacial interglacial climate cycles since this platform began to uplift in the late middle pleistocene this result indicates that uplift may be necessary in large terrace staircase genesis it can force the river system to downcut deeply enough during climatic transitions to separate terrace levels adequately favoring the generation and subsequent preservation of the terrace treads the terrace sequence of the yellow river in the eastern fenwei basin therefore can be considered as a combined archive of climate change and local tectonic activity

decadal changes in glacier parameters in the cordillera blanca peru derived from remote sensing we present spatial patterns of glacier fluctuations from the cordillera blanca peru glacier area terminus elevations median elevations and hypsography at decadal timescales derived from 1970 aerial photography 2003 spot5 satellite data geographic information systems gis and statistical analyses we derived new glacier outlines from the 2003 spot images and ingested them in the global land and ice measurements from space glims glacier database we examined changes in glacier area on the eastern and western side of the cordillera in relation to topographic and climate variables temperature and precipitation results include 1 an estimated glacierized area of 569 6 21 km 2 in 2003 2 an overall loss in glacierized area of 22 4 from 1970 to 2003 3 an average rise in glacier terminus elevations by 113 m and an average rise in the median elevation of glaciers by 66 m showing a shift of ice to higher elevations especially on the eastern side of the cordillera and 4 an increase in the number of glaciers which indicates disintegration of ice bodies annual air temperature showed a significant upward trend in the last 30 years with larger temperature increases at lower elevations there was a slight but not significant decrease in precipitation our results are consistent with glacier retreat and warming trends noted in the last three decades in the tropics

regional stress field of the indian plate we have calculated the regional stress field in the indian plate implementing dependence of slab pull and ridge push on the age of the oceanic lithosphere in the finite element procedure the high level of the calculated stress field order of a few kbar and the dominance of compression in the plate are consequences of the unique dynamic situation of the present day indian plate the calculated stress field explains the concentration of intraplate deformation in the region of the ninetyeast ridge and yields insight into the variations in stress directions in the australian continent

luminescence and amino acid racemization chronology of the loess paleosol sequence at suttő hungary abstract the loess paleosol sequences in hungary provide an excellent upper pleistocene climate archive of the carpathian basin loess deposits up to 20 m thick cover the sutt travertine complex located in the very northern part of hungary next to the right bank of the danube river the loess is intercalated with two weakly developed greyish horizons two thinner brownish steppe like soils and a pedocomplex including a reddish brown clay enriched horizon covered by a chernozem like paleosol infrared optically stimulated luminescence irsl dating was applied on polymineral fine grain material to determine the depositional age of the loess the uppermost loess yields irsl age estimates ranging from 15 to 40 ka the loess on top of the pedocomplex yields irsl age estimates ranging from 48 to 60 ka the pedocomplex most likely correlates with the marine oxygen isotope stage mis 5 interglacial period the loess from below the pedocomplex was deposited during the penultimate glaciation as evidenced by amino acid racemization aar results further independent age control is provided by radiocarbon dating for the upper part of the profile and by uranium series 230th 234u ages correlating the travertine below the loess with mis 7 8 the magnetic susceptibility record through the sequence shows a strong correlation with the loess layers and soil horizons

wind erosion under cold climate a pleistocene periglacial mega yardang system in central europe western pannonian basin hungary abstract mega yardangs are known to form under extremely arid warm or in some instances moderate climates here we report on the mega yardang field of the pannonian basin hungary which was uniquely formed under periglacial probably semi arid conditions and discuss its implications on factors controlling yardang formation in general the yardang field is composed of advanced streamlined forms and of less aerodynamic ridges separated by well developed corridors the length of the largest features exceeds 60 km their height varies around 150 m together with ventifacts deflation hollows and wind blown sand areas the yardang field is part of an integrated eolian feature system driven by northerly to northwesterly winds dating of ventifact surfaces with in situ produced cosmogenic nuclides places the onset of significant wind erosion to the early pleistocene 1 5 ma osl dated young loess from which well developed yardangs were sculpted and wind blown sands show that eolian action continued until the early holocene the long temporal range of wind erosion compared to average yardang formation rates and the rarity of advanced yardang forms indicate intermittent and relatively short most probably millennial scale deflation periods since the early holocene the system has been inactive and demonstrates that yardangs can persist in a recognizable form for several millennia even under less arid conditions the main control on yardang formation appears to be the existence of strong unidirectional winds in the pannonian basin facilitated mainly by the channeling effect of topographic lows in the surrounding mountain chains yardangs can form even under semi arid climates however the rarity of these occurrences suggests that this requires a special association of environmental conditions yardang formation is facilitated by homogeneous lithology namely by widespread weakly consolidated sandy sediments the distribution of yardang fields is controlled by vertical neotectonic movements which provided uplifted areas to be sculptured and topographic obstacles that sheltered downwind sediments faulting can be excluded as a controlling factor in mega yardang formation nor is the role of jointing supported

source mechanisms of earthquakes near mid ocean ridges from body waveform inversion implications for the early evolution of oceanic lithosphere to investigate the early tectonic evolution of oceanic lithosphere we present a synthesis of the characteristics of near ridge earthquakes i e earthquakes which occur off the axis of major mid ocean spreading centers but in lithosphere less than 35 m y old near ridge seismicity for the past two decades has been rather evenly distributed along the major ridge systems with the exception of the central indian ocean and the eastern part of the cocos plate which have experienced a high rate of earthquake activity during that time for 32 near ridge earthquakes we determined the double couple orientation seismic moment centroid depth and source time function using a formal inversion technique based on matching synthetic and observed p and sh waveforms all types of faulting styles are observed seismogenic deformation in young oceanic lithosphere is concentrated in the first 15 m y and occurs almost entirely in the uppermost mantle from just below the moho to depths at which the temperature estimated from standard thermal models exceeds 800 c thrust faulting is not observed at depths greater than 10 km below the seafloor the deepest near ridge earthquakes are generally characterized by normal faulting focal mechanisms with the t axis oblique or perpendicular to the local spreading direction most of these earthquakes occur in the central indian ocean the transition from mechanisms characteristic of ridge axes to those characteristic of the near ridge environment occurs within the first few million years for lithosphere less than 35 m y old horizontal compressive stress associated with the cooling and subsidence of the lithosphere ridge push does not appear to be the dominant source of stress released in earthquakes this result may be used to place a lower bound of several hundred bars on the typical stress difference in young oceanic lithosphere this bound together with the observed depth of faulting implies that the strain rate associated with seismic deformation is locally at least 10 15 s 1 we propose that thermoelastic stresses associated with plate cooling play an important role in near ridge earthquakes this source of stress can account for the mechanisms and depths of many near ridge earthquakes and for the concentration of activity in very young lithosphere the comparative aseismicity of the oceanic crust may reflect the concentration of thermoelastic stress below the moho due to different material properties for the crust and upper mantle or the early release of thermoelastic stresses through hydrothermal circulation and cracking throughout the crust at or near the ridge axis the higher level of near ridge seismicity in the indian ocean may be the result of modification or enhancement of the more typical near ridge stress state by such local processes as the continental collision between india and asia or active secondary convection beneath the young lithosphere of the indian plate

historically unprecedented global glacier decline in the early 21st century observations show that glaciers around the world are in retreat and losing mass internationally coordinated for over a century glacier monitoring activities provide an unprecedented dataset of glacier observations from ground air and space glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass balance data relating to the impact that glaciers exercise on global sea level fluctuations or on regional runoff in this study we provide an overview and analysis of the main observational datasets compiled by the world glacier monitoring service wgms the dataset on glacier front variations 42000 since 1600 delivers clear evidence that centennial glacier retreat is a global phenomenon intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the little ice age or holocene glaciological and geodetic observations 5200since 1850 show that the rates of early 21st century mass loss are without precedent on a global scale at least for the time period observed and probably also for recorded history as indicated also in reconstructions from written and illustrated documents this strong imbalance implies that glaciers in many regions will very likely suffer further ice loss even if climate remains stable

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

luminescence dating of upper pleistocene loess from the island of susak in croatia abstract the loess paleosol sequence on the island of susak is a detailed late pleistocene archive of climate change in the north adriatic sea of croatia quaternary deposits on susak are up to 90 m thick and consist of loess loess derivatives and sand intercalated by numerous paleosols and at least three tephra layers infrared stimulated luminescence irsl dating was carried out on polymineral fine grained material thirteen samples were collected from two sections on susak to study the timing of loess accumulation and soil formation the single aliquot regenerative sar protocol as well as the multiple aliquot additive dose maad protocol were applied for equivalent dose d e determination the irsl ages were fading corrected independent age control is provided by radiocarbon dating of charcoal remains the results show that loess and loess derivatives from the investigated sections represent a very detailed record correlating to the marine isotope stage mis 3 with short periods of stronger sand deposition and occasional volcanic activity the extraordinary thickness of the deposits is very likely related to the vicinity of the river po plain which extended to the southeast due to marine regressions of the adriatic sea during the cold periods of the pleistocene

the neogene evolution and hydrocarbon potential of the pannonian basin in croatia sedimentary basin fill of the central paratethys in croatia consists of variable deposits the oldest are the egerian and eggenburgian paralic and marine sediments that were determined only in the western marginal part of the studied area the neogene sedimentary sequence in major subsidences the sava and drava basins starts with ottnangian karpatian transitional deposits that are covered by badenian marine and pannonian pontian brackish to freshwater formations pliocene and quaternary terrestrial deposits cover major parts of the former depositional basins three stages of structural development of the sw pannonian basin are differentiated initial structural changes between oligocene and early miocene main extensional processes that prevailed in early and middle miocene and transpression during pliocene and quaternary the newly formed structures are essential for hydrocarbon accumulation the main source rocks are lower to middle miocene marly limestones and limy marls hydrocarbon accumulations are found in the uplifted and fractured parts of the neogene basement and in the lower to middle miocene coarse grained clastics but the most important reservoir rocks are the upper miocene sandstones

a diffuse plate boundary model for indian ocean tectonics it is suggested that motion along the virtually aseismic owen fracture zone is negligible so that arabia and india are contained within a single indo arabian plate divided from the australian plate by a diffuse boundary the boundary is a zone of concentrated seismicity and deformation commonly characterized as intraplate the rotation vector of australia relative to indo arabia is consistent with the seismologically observed 2 cm yr of left lateral strike slip along the ninetyeast ridge north south compression in the central indian ocean and the north south extension near chagos

sensitivities of the equilibrium line altitude to temperature and precipitation changes along the andes abstract equilibrium line altitudes elas of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales however accurate interpretations of ela fluctuations rely on a quantitative understanding of the sensitivity of elas to changes in climate we applied a full surface energy and mass balance model to quantify ela sensitivity to temperature and precipitation changes across the range of climate conditions found in the andes model results show that ela response has a strong spatial variability across the glaciated regions of south america this spatial variability correlates with the distribution of the present day mean climate conditions observed along the andes we find that elas respond linearly to changes in temperature with the magnitude of the response being prescribed by the local lapse rates ela sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere temperature sensitivities are greatest in the inner tropics precipitation becomes more important in the subtropics and northernmost mid latitudes these results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes

differential thermal stresses in the earth summary rocks have a significant thermal expansion coefficient and a high modulus of elasticity small thermal changes can therefore generate very substantial stresses a convenient idealized example is the mechanically free cooling thermal boundary layer in a material that suddenly turns from plastic to rigid in cooling through a rigidus temperature this simplified case can be solved analytically for both a linear and an error function temperature profile a compressed layer develops near the surface with a logarithmic singularity of stress at the boundary at a depth of 0 2 of the elastic thickness the stress changes to tensile and peaks at 15 per cent of the confined shrinkage stress in the middle of the rigid layer the situation is similar to the stresses in one half of a piece of tempered glass like the tempered glass both the cooling lithosphere and a plated boundary to a magma chamber are subject to breakage when cracks are induced in the tensile layer positive pore magma pressure is required to overcome confining pressure at depth in the lithosphere but cracking could become catastrophic in the plated boundary to a near surface magma chamber

dating middle pleistocene loess from stari slankamen vojvodina serbia limitations imposed by the saturation behaviour of an elevated temperature irsl signal abstract recent advances in post ir irsl dating have led to breakthroughs in dating upper middle pleistocene loess sequences here an elevated temperature post ir ir protocol using a second ir stimulation temperature of 290 c is applied to eleven polymineral fine grain 4 11 m samples from the lower part of the middle lower pleistocene stari slankamen loess palaeosol sequence with the aim of refining the site s age model and investigating the behaviour of both the ir50 and the pirir290 signals in material close to or in luminescence signal saturation both signals from the 8 samples below the prominent erosion surface represented by a gravel layer at 13 m were found to be in field saturation i e no systematic increase in burial dose with depth the average ratio of the sensitivity corrected natural signal to the laboratory saturation level for the pirir290 is 1 00 0 03 n 8 indicating that field saturation is equal to laboratory saturation for this signal minimum equivalent dose estimates were calculated from 2 d0 values giving minimum age estimates of 230 390 ka this result suggests an upper limit for dating these loess deposits of 300 ka the age estimate of the younger sample ssk2 is in good agreement with the quartz osl age showing that the pirir290 signal is bleachable in nature and can be used to date material as young as 20 ka our data suggest that the loess unit v l2 accumulated during marine isotope stage mis 6 and that the erosional event marked by an unconformity and gravel layer between loess units v l2 and v l3 has a minimum age of 170 ka pedocomplex v s1 can be correlated with the complete mis 5 period furthermore we suggest a minimum age of 250 ka for the loess unit v l3 and palaeosols v s3 v s4 and v s5 considerably older than proposed by many previous studies