flow transmission along an arid zone anastomosing river cooper creek australia cooper creek is characterized by an exceptionally wide floodplain and a complex system of anastomosing channels which together can accommodate a large range of highly variable flows in consequence flood frequency curves are unusually steep with minimal tributary contribution over the two study lengths currareva nappa merrie 400 km and nappa merrie innamincka 32 km downstream output is largely controlled by upstream input so that similar flow regimes and hydrograph forms can be maintained despite transmission losses and the variable activation of channels input output relationships defined in terms of total flow volume and peak discharge suggest that above a threshold flow of about 25 duration transmission losses exceed 75 on average over the currareva nappa merrie length the large difference in absorption between primary channels on the one hand and subsidiary channels and the floodplain surface on the other means that transmission losses vary non linearly with stage they are relatively low when flow is confined to the primary channels but increase at higher stages as lesser channels and the floodplain are activated early levels do not recur until flows of 0 5 duration are attained when output input ratios increase rapidly with discharge the influences of seasonality and background flow on output discharge are small relative to that of input discharge despite the long river distance peak flows at currareva and nappa merrie are well correlated however over the shorter nappa merrie innamincka length with its more confined system of channels correlations are better and transmission losses less they vary from 60 just above the threshold discharge to lo at flows below 20 duration over this length outflow hydrographs can be effectively estimated by the three parameter muskingum procedure at least on an event by event basis but further application must await additional records to understand fully how the parameters vary in an environment where streamflow is transmitted through a highly variable system of channels

regional recharge to a karst aquifer estimated from chemical and isotopic composition of diffuse and localised recharge south australia the relative importance of different recharge mechanisms has been investigated for a karstic area in a subhumid to semi arid region of south australia the chemical and isotopic signature 2h and 18o of regional groundwater sampled from shallow bores in the study area as well as water from sinkholes swamps drainage bores and water extracted from soil in the unsaturated zone has been measured point estimates of recharge based on data from the unsaturated zone have been combined with temporal and spatial trends in the isotopic and chemical signature of the groundwater to provide a regional estimate for recharge for different land elements for approximately half of the study area which has predominantly clay soils recharge is low 10 mm year 1 and the groundwaters within the study area are derived from lateral flow from the east for the remaining area recharge has significantly increased since agricultural development and has affected the groundwater system groundwater within the vicinity of irrigation areas has shown marked increases in salinity over the past 30 years owing to the impact of irrigation drainage waters other areas not under irrigation but cleared of native vegetation and replaced by shallow rooting pastures also show increased salinity in parts where there are sandy soils in these areas saline soil water from the unsaturated zone has been displaced by the increased recharge since clearing the effect of clearing on areas of clay surface soils has not increased recharge to the same extent and groundwater salinity levels are largely unchanged areas where salinity levels are rising correlate well with increased 14c activity and depleted 13c concentrations of the groundwater suggesting that these isotopes may be an early indicator of areas of enhanced recharge

permo carboniferous magmatism of the northeast german basin abstract variscan continent continent collision in central europe was followed by a period of syn to late tectonic magmatism involving the extrusion of large volumes of permosilesian age volcanic rocks particularly in the northeast german basin the volcanic suite up to ca 2000 m thick comprises rhyolites acid and basic andesites and tholeiitic and alkali basalts tectono geochemical analysis in conjunction with volume calculations and petrography reveals changes in volcanic activity over time a total of five eruptive stages are recognised beginning in the stephanian and extending up into the upper rotliegend permian these include the stephanian late carboniferous andesite pre ignimbrite stage i lower rotliegend permian age explosive ignimbrite stage ii post ignimbrite stage iii late rhyolite stage iv and upper rotliegend permian age late basalt stage v in addition several volcanic centres including at least two large caldera like structures are recognised the total calculated volume for the northeast german basin volcanics is ca 48 000 km3 comprising rhyolitic rocks and ignimbrites ca 70 andesitic rocks ca 26 and basalts with cogenetic dolerites ca 4 regional variations in composition and geochemistry are related to diverse crust mantle regimes which correlate with differing positions relative to the heterogeneous basement of the variscan foredeep or within the rhenohercynian orogenic zone the crustal thickening and increasing generation depth of the mafic magmas from north to south may reflect the presence of a pre existing subduction influenced basaltic magma source

delamination and detachment of a lithospheric root abstract orogens can be formed by shortening of the lithosphere on time scales much shorter than that of thermal diffusion for time scales of a few ma the major part of the uplift of an orogen which may occur during the transition from crustal shortening to extension may be due to delamination of the mantle lithosphere rather than to convective thinning the negative buoyancy forces of a lithospheric root may cause lateral shortening while the lithospheric root delaminates peels off from the crust detaches and is replaced by hot upwelling asthenosphere this provides a large input of heat into the crust geological observations show that the late orogenic phase may be characterized by volcanic activity high temperature low pressure metamorphism extension high heat flow and a rapid within a few ma increase of the topography we present dynamically and thermally consistent numerical models of the evolution of an orogenic root mantle rheology is based on laboratory data of olivine while models with the rheology of olivine do not allow for delamination due to its very high viscosity the incorporation of a quasi brittle rheology is necessary for modelling delamination of the mantle lithosphere successful delamination models are always associated with a rapid change in topography we examined the parameter range of our models and found different regimes of behaviour of the orogenic root of the mantle lithosphere no delamination delamination delamination and full detachment for a fixed viscosity of the upper crust of 1023 pa s delamination occurs for a range of viscosities of 1023 pa s to 1020 pa s for the lower crust depending on the thickness of the lithospheric root but full detachment of the delaminated lithospheric slab only occurs if the viscosity of the lower crust is greater than approximately 1021 pa s hot asthenosphere is welling up into the gap opening during delamination further implications of our models are lithospheric roots or unsupported slabs of at least 100 170 km depth extent are needed to provide sufficient negative buoyancy to allow delamination and detachment in all delamination models significant amounts of lower crustal material are subducted into the mantle in applying our models to selected orogens we argue that mantle delamination may have played an important role in the variscan and the himalayan orogenies

emplacement textures in late palaeozoic andesite sills of the flechtingen roslau block north of magdeburg germany

the application of electromagnetic techniques to groundwater recharge investigations abstract the use of electrical methods for estimating spatial patterns of groundwater recharge was evaluated at a field site in southeastern australia here recharge increased from less than 0 2 mm year 1 under native eucalyptus vegetation to between 1 and 14 mm year 1 under dryland agriculture this increase in recharge results in progressive leaching of salts in the soil profile differences in recharge can be estimated from differences in depth of leaching the estimated recharge rates are correlated with soil texture with higher recharge rates generally occurring through sandier soils the relationships of recharge to salt content and soil texture both contribute to lower apparent electrical conductivities for higher recharge rates the effect of recharge rate on measured apparent electrical conductivities was modelled for various geophysical devices including frequency domain fem and time domain tem electromagnetic instruments and direct current resistivity the soil texture effect was shown to have a greater effect than the solute leaching effect in determining the correlation between recharge and apparent electrical conductivity analysis of sensitivity to geological noise showed that variations in soil type below 2 m could disguise any correlation correlations between recharge rate measured at core sites from chloride tracer techniques and apparent electrical conductivity measured with fem electromagnetic devices supported the conclusions of the model for dc resistivity and tem methods correlations between recharge and apparent electrical conductivity were not significant although for resistivity this may be due partly to the small number of measurements made the fem device most sensitive to variations in recharge had an operating frequency of 9 8 khz at lower frequencies the sensitivity is reduced as the instruments are sensing too deeply the poor correlations for tem as compared with fem are due probably to the relatively deeper penetration of the tem instrument used in the study rather than any inherent differences between the techniques because the major reason for the correlation between recharge and apparent electrical conductivity is soil texture in this area the geophysical devices are mostly mapping soil type

road impacted sediment and water in a lake ontario watershed and lagoon city of pickering ontario canada an example of urban basin analysis abstract the world is increasingly urban but there are few studies of how contaminated water and sediment move through urban basins with their built landscapes and complexly disturbed geology the central canadian city of pickering ontario sprawls across a small 27 km 2 densely urbanized pop 53 000 watershed and is underlain by pleistocene glacial sediments and thick artificial fill deposits almost 80 of the area is hardened by impervious cover road and rail lines cover 40 and include canada s busiest highway 12 lane highway 401 177 000 vehicles per day in 2003 the basin discharges to lake ontario through a small 85 ha shallow 2000 mg l 1 occur during winter thaws in creeks downstream of the highway enhanced stream bank erosion as a consequence of flashy storm runoff from road surfaces moves 100 tonnes of contaminated sediment to frenchman s bay each year instantaneous suspended sediment concentrations in storm runoff are as high as 1600 g m 3 and loadings of sulphate so 4 2 nutrients reach 594 kg h 1 metals and e coli in road runoff are all elevated well above canadian water quality standards these findings underscore findings from other urban areas regardless of regional climate that transportation corridors are a major global source of contaminated water and sediment

on the origin of the southern permian basin central europe abstract a detailed study of the structural and stratigraphic evolution of the southern permian basin during latest carboniferous to early jurassic times supported by quantitative subsidence analyses and forward basin modelling for 25 wells leads us to modify the conventional model for the rotliegend zechstein development of this basin the late permian early jurassic tectonic subsidence curves are typical for a permian to early triassic extensional stage that is followed by thermal subsidence however a purely extensional model is extremely problematic because active faulting during this time is minor and generally hard to document using inverse techniques to model the subsidence curves we quantitatively show that a significant component of late permian and triassic tectonic subsidence can be explained by thermal relaxation of early permian lithospheric thinning and by delayed infilling of paleo topographic depressions that developed during the early permian in this interpretation stephanian autunian wrenching resulted in thermal destabilisation of the lithosphere deep fracturing of the crust disruption and erosion of its sedimentary cover and regional uplift of the area of the future southern permian basin upon termination of wrench tectonics and associated volcanism towards the end of the autunian the southern permian basin began to subside in response to thermal contraction of the lithosphere the evolving basin was isolated from the world oceans and had subsided possibly up to some 700 m below their level at the beginning of upper rotliegend sedimentation after catastrophic flooding of this paleo topographic depression at the beginning of the zechstein changing sea level sedimentation and subsidence rates remained essentially in balance although the effects of triassic rifting overprinted parts of the southern permian basin its overall subsidence pattern persisted well into the jurassic in contrast to the remainder of the southern permian basin permian and triassic crustal extension contributed significantly to the subsidence of the polish trough

calderas and caldera structures a review abstract calderas are important features in all volcanic environments and are commonly the sites of geothermal activity and mineralisation yet it is only in the last 25 years that a thorough three dimensional study of calderas has been carried out utilising studies of eroded calderas geophysical analysis of their structures and analogue modelling of caldera formation as more data has become available on calderas their individuality has become apparent a distinction between caldera caldera complex cauldron and ring structure is necessary and new definitions are given in this paper descriptions of calderas based on dominant composition of eruptives basaltic peralkaline andesitic dacitic rhyolitic can be used and characteristics of each broad group are given styles of eruption may be effusive or explosive with the former dominant in basaltic calderas and the latter dominant in andesitic dacitic rhyolitic and peralkaline calderas four end member collapse styles occur plate or piston piecemeal trapdoor and downsag but many calderas have multiple styles features of so called funnel and chaotic calderas proposed in the literature can be explained by other collapse styles and the terms are considered unnecessary ground deformation comprises subsidence or collapse essential characteristics of a caldera and uplifting doming and fracturing due to tumescence and or resurgence frequent but not essential collapse may occur on pre existing structures such as regional faults or on faults created during the caldera formation and the shape of the collapse area will be influenced by depth size and shape of the magma chamber the final morphology of a caldera will depend on how the caldera floor breaks up whether collapse takes place in one event or multiple events whether vertical movement is spasmodic or continuous throughout the eruptive sequence and whether blocks subside uniformly or chaotically at one or more collapse centres a meaningful description of any caldera should therefore include number of collapse events presence or absence of resurgence caldera floor coherency caldera floor collapse geometry and dominant composition of eruptives

late paleozoic volcanism in the central part of the southern permian basin ne germany w poland facies distribution and volcano topographic hiati based on facies analysis of more than 5 500 m cores of 45 deep wells three large sub provinces have been defined for the lower rotliegend volcanic rocks in the central southern permian basin spb in northeastern germany and western poland additional data came from unpublished descriptions of more than 200 wells the three sub provinces are a the mecklenburg vorpommern sub province mvsp dominated by silica rich lava domes and subvolcanic intrusions b the eastern brandenburg sub province ebsp dominated by a mg andesite shield volcano complex which extends into western poland and c the flechtingen altmark sub province fasp with prominent ignimbrite sheets punctuated by lava domes and flows whereas in ne germany thickness of up to 2 300 m have been found in places in western poland ignimbrites and other pyroclastic deposits as well as andesitic and silica rich lava complexes accumulated successions of a few hundreds of meters a hiatus of up to 30 ma occurs between the lower rotliegend volcanic and sedimentary rocks asselian sakmarian and upper rotliegend ii sediments upper wordian capitanian upper rotliegend i deposits are known from a few wells and outcrops only previous studies postulated solely intrabasinal tectonics to account for this major unconformity however under semiarid to arid conditions as assumed for the rotliegend of the spb both sio2 rich lava complexes and silica poor shield volcanoes can be expected as being extremely resistant to weathering and erosion most probably these bodies drowned in a regolith formed by physical weathering rarely removed by torrential rain thus the silica rich lava complexes and the shield volcanoes in the central european basin system cebs can be viewed as long living morphological highs with intervolcanic depressions in between in these intervolcanic depressions syn to postvolcanic successions of conglomeratic to sandy alluvial fan sediments and lake to mud flat deposits accumulated during the upper rotliegend i they show numerous pedogenic horizons representing times of non deposition during the upper rotliegend ii the remaining volcano topography was filled up with alluvial eolian and playa deposits in some places in western poland covering was not complete until the zechstein latest permian at the same time soil formation and or erosion in the upper part of sio2 rich complexes and shield volcanoes remained subordinate consequently the volcano topographic hiatus on top of the volcanic complexes comprises the maximum period of time whereas in the intervolcanic depressions this time splits into periods of deposition and numerous minor intraformational hiati intrabasinal tectonic activity cannot be ruled out as one major control of the rotliegend depositional evolution in the subsiding spb however the presence of weathering resistant volcanic edifices led to the formation of long lasting depositional gaps in many regions of the central spb

a review of aridity and groundwater surface hydrological studies are seen as inadequate in hyperarid and arid areas to provide reliable estimates of recharge in most such areas surface discharges are not present so that assessments of groundwater resources are dependent upon ground interpretation and denied the flow control found in assessments elsewhere groundwater models show that gradients are sustained by long term dewatering and very small amounts of modern indirect recharge recharge indications are well within the error of a hydrological balance discharges appear equally small the development of groundwater in arid areas frequently faces problems of salination due to recycling of irrigation water and rising groundwater heads abstraction is often inadequately managed so that uncontrolled mining of groundwater occurs the advantage that groundwater has however is that it offers staged development and staged appraisal

centrifuge modeling studies of site response in soft clay over wide strain range abstractcentrifuge models of soft clay deposits were shaken with suites of earthquake ground motions to study site response over a wide strain range the models were constructed in an innovative hinged plate container to effectively reproduce one dimensional ground response boundary conditions dense sensor arrays facilitate back calculation of modulus reduction and damping values that show modest misfits from empirical models low amplitude base motions produced nearly elastic response in which ground motions were amplified through the soil column and the fundamental site period was approximately 1 0 s high intensity base motions produced shear strains higher than 10 mobilizing shear failure in clay at stresses larger than the undrained monotonic shear strength the authors attribute these high mobilized stresses to rate effects which should be considered in strength parameter selection for nonlinear analysis this nonlinear response deamplified short period spectral accelerations and lengthened the

learning of dynamic soil behavior from downhole arrays an increasing number of downhole arrays are deployed to measure motions at the ground surface and within the soil profile measurements from these arrays provide an opportunity to improve site response models and to better understand underlying dynamic soil behavior parametric inverse analysis approaches have been used to identify constitutive model parameters to achieve a better match with field observations however they are limited by the selected material model nonparametric inverse analysis approaches identify averaged soil behavior between measurement locations a novel inverse analysis framework self learning simulations selfsim is employed to reproduce the measured downhole array response while extracting the underlying soil behavior of individual soil layers unconstrained by prior assumptions of soil behavior selfsim is successfully applied to recordings from lotung and la cienega the extracted soil behavior from few events can be used to reliably predict the measured response for other events the field extracted soil behavior shows dependencies of shear modulus and damping on cyclic shear strain level number of loading cycles and strain rate that are similar qualitatively to those reported from laboratory studies but differ quantitatively

basin geomorphological controls on the mechanism of recharge and discharge and its effect on salt storage and mobilization comparative study using geophysical surveys abstract downhole electromagnetic em profiles have been used to study the salt distribution in four catchments in the wheatbelt of western australia the good correlation r 2 0 7 0 9 obtained by relating the apparent conductivity profiles measured by the downhole em with salt profiles from soil cores enabled estimation of the salt storage in the uncored wells the salt distribution was compared with ground conductivity surveys using em31 and em34 instruments in three catchments and with an input aerial electromagnetic survey aem in a fourth catchment the study revealed the presence of five types of apparent electrical conductivity profiles eca which are correlated with the basin geomorphological units the conductivity profiles are 1 low eca recharge profile 2 subsurface peak discharge profile 3 two bulge profiles a single bulge accumulation weathering profile and a split aquifer development profile 4 reduced bulge leaching profile 5 high eca irregular palaeochannel profile the salt distribution showed a systematic increase in salinity from the watersheds to the valleys with salinity increasing upstream of geological structures the salt distribution was found to be controlled by the geomorphologic properties of the basins which control the hydrological and hydrogeological processes and by the recharge discharge mechanisms which influence salt mobilization and accumulation

facies architecture variations and seismogenic structures in the carboniferous permian saar nahe basin sw germany evidence for extension related transfer fault activity abstract sedimentary and volcanic strata in the late orogenic intermontane saar nahe basin preserve a record of sedimentary responses to motion on contemporaneously active faults studies of such deposits can constrain both concepts for lateral and vertical sedimentary facies development and geometric and kinematic models of intrabasinal extension during carboniferous permian syn rift development the saar nahe basin underwent a marked intrabasinal segmentation generated by the offsets of longitudinal normal faults and dextral oblique strike slip faults which were developed perpendicular to the sw ne basin elongation the latter are interpreted as transtensional transfer faults which compartmentalized the basin into segments of differing structural style bed thickness and facies development the fault zones themselves bound an assemblage of variously sized uplifted and downthrown blocks showing variable magnitudes and senses of displacement their activities are recorded by the contrasting depositional histories of tephrostratigraphically constrained sedimentary units occupying footwall and hanging wall block positions during basin filling the influence of faults on the depositional system is seen in their effect as topographic barriers thus restricting free dispersal and mixing of sediment particular sedimentary facies such as coals and biogenic limestones are confined to the immediate vicinity of the fault zones indicating the isolation of sediment starved areas near downthrown hanging walls other fault generated depressions acted as depositional traps favouring considerable accumulations of basaltic lavas volcaniclastic mass flows and fluvial channel deposits in contrast uplifted footwalls are characterized by the formation of unconformities and pedogenic features the abundance of syn tectonic deformation structures such as sediment filled fissures intraformational breccias series of micro faults clastic dykes and other water escape features within syn rift strata and their distinct spatial linkage to fault zones implies considerable seismically triggered processes associated with faulting the combined occurrence of abrupt variations in facies architecture across faults and seismotectonic structures suggests that the basin subsidence history involved a series of events rather than gradual change

reflection seismic constraints on paleozoic crustal structure and moho beneath the ne german basin abstract a 330 km long ne sw trending seismic transect across the ne german basin combined with a 75 km long perpendicular cross line in the basin centre reveals the structure of this intracontinental basin between the stable precambrian baltic shield and the weaker mid european variscides the combination of high fold vibroseis and low fold explosive seismic profiling images both upper and lower crustal structures in detail distinct faults related to a rift stage are not observed below the permian sedimentary basin but there is evidence of lower crustal thinning a moho pattern less reflective below the basin centre than at the margins may be related to magmatic underplating the rather flat lying moho dips slightly towards the basin margins structures further north suggest a southern extent of baltica below the ne german basin the caledonian accretionary wedge may be outlined by sw dipping mid crustal reflectors beneath the basin

water recharge and solute transport through the vadose zone of fractured chalk under desert conditions this study focuses on water flow and solute migration through unsaturated fractured chalk in an arid area the chalk underlies a major industrial complex in the northern negev desert where groundwater contamination has been observed four dry drilling holes were bored through the vadose zone core and auger samples collected at 30 to 50 cm intervals were used for chemical and isotopic analyses enabling the construction of the following profiles 1 a tritium profile to estimate the rate of water flow through the unsaturated zone 2 oxygen 18 and deuterium profiles to assess the evaporation of water at land surface before percolation and in the upper part of the vadose zone after infiltration and 3 chloride and bromide profiles as tracers for inert solutes and pollutants the tritium and bromide profiles showed the rate of infiltration through the unsaturated matrix to be very slow 1 6 11 cm yr the chemical and isotopic data from the core holes suggested that the pore water changes characteristics with depth close to land surface the pore water is strongly evaporated 18o 5 94 and highly concentrated 29 meq cl 100 g rock but changes gradually with depth to amore dilute concentration 4 meq cl 100 g rock and isotopically depleted composition 18o 4 4 closer to the isotopic composition of precipitation and groundwater nearby monitoring wells have shown anthropogenic contribution of heavy metals organic compounds and tritium nativ and nissim 1992 a conceptual model is proposed in which a small portion of the rainwater percolates downward through the matrix while a larger percentage of the percolating water moves through preferential pathways in fractures the water flowing through the fractures penetrates the matrix across the fracture walls where it increases the tritium concentrations depletes the stable isotopic composition and dilutes the salt concentrations the observed rapid downward migration of tritium and heavy metals through the profuse fractures makes the chalk inefficient as a hydrologic barrier

permo carboniferous climate early pennsylvanian to late permian climate development of central europe in a regional and global context a well justified stratigraphical correlation of continental successions and new palaeogeographic reconstruction of pangaea reveal new insights into the northern pangaean climate development influenced by palaeogeography palaeotopography glacio eustatic sealevel changes and ocean currents the overall permo carboniferous aridization trend was interrupted by five wet phases these are linked to the gondwana icecap the aridization and weakening of wet phases over time were not only caused by the drift of northern pangaea to the arid climatic belt but also by the successive closure of the rheic ocean which caused the expansion of arid semi arid environments in the lower middle permian the end of the gondwana glaciation rearranged ocean circulation leading to a cold coast parallel ocean current west of northern pangaea blocking moisture coming with westerly winds the maximum of aridity was reached during the roadian wordian the trans pangaean mountain belt was non existent its single diachronous parts never exceeded an average elevation of 2000 m the maximum elevation shifted during time from east to west the hercynian orogen never acted as an orographic east west barrier and the inter tropical convergence zone was widely displaced causing four seasons dry summer winter wet spring autumn at the equator and a strong monsoon system the climate history of the european realm during the late carboniferous pennsylvanian and permian is stored in many solitary basins fig 1 within the hercynian orogen and the foreland basin the story of westphalian climate is well known because of the numerous investigations of the coal bearing variscan foredeep the younger westphalian is characterized by a slight aridization abbink van kronijnenburgvan cittert 2003 oplustil 2004 which was accompanied by an increase of seasonality nevertheless the environment was strongly influenced by the ocean and epi continental seas with multiple transgression events the last extensive marine ingression was the aegir mansfield band westphalian b c the post westphalian climate development is more differentiated and

an improved elastic viscoplastic soil model this paper develops an improved and accessible framework for modelling time dependent behaviour of soils using the concepts of elasticity and viscoplasticity the mathematical description of viscop

factors affecting groundwater recharge following clearing in the south western murray basin abstract data from 18 field studies in the south western murray basin australia and a simple water balance model were used to study the importance of factors which affect diffuse recharge in that area generally as the texture of the soil became heavier the recharge decreased under cropped land as the clay content in the top 2 m of the soil profile increased from 0 to 20 recharge decreased by one order of magnitude from about 30 to about 3 mm year 1 for a mean annual rainfall of 310 380 mm as mean annual rainfall increased the mean annual recharge also increased sites with an average clay content of about 10 in the top 2 m and a mean annual rainfall of 270 mm had an estimated recharge of about half that of sites with a mean annual rainfall of 310 380 mm data from land which was grazed but not cropped showed similar relationships however the data set did not allow a detailed analysis of the effect of land use on recharge

volcanic geomorphology an overview abstract the review examines the role of geomorphology in analyzing the volcanoes on earth five objectives are stressed first classifications of volcanic landforms should be improved to take care of the complexity in volcanic landform generation as magmatic systems style of eruption and the erupted material all influence the morphology second geomorphology should contribute to the science of volcanology through its capability in reconstructing growth stages in complex volcanoes and also in analyzing the structural factors which contribute to the catastrophic collapse of volcanoes third geomorphology can contribute to physical volcanology by assessing the effects of topography on transport erosion and deposition of volcanogenic flows and identifying the sources and climatic tectonic conditions which govern the emplacement of volcaniclastic deposits fourth volcanic geomorphology a identifies sedimentary facies associations b constructs facies models for dynamic volcano delivery systems and c analyzes the characteristics of sediment gravity flows in order to determine relevant parameters for modelling their behaviour fifth process oriented geomorphology is critical in developing accurate methods for measuring rates of geomorphic processes that shape ephemeral volcanic constructs and for evaluating and comparing geomorphic impacts on disturbed catchments and the related hydrologic response before during and after eruptions this should help to refine parameters for the exponential decay model finally volcanic geomorphology is essential for risk assessment through geomorphic hazard zonation and composite risk zonation such treatments are necessary in order to face the enhanced challenge posed by the combination of natural hazards and the increasing number of people who are at risk around volcanoes

sedimentation volcanism and subvolcanic intrusions in a late palaeozoic intramontane trough the intra sudetic basin sw poland

tectonic evolution of the mid polish trough modelling implications and significance for central european geology abstract the polish basin forms the easternmost part of the permian mesozoic northwest european basin the depocentral axis of the polish basin the mid polish trough mpt is superimposed on the boundary between the west european phanerozoic and east european proterozoic crustal domains within the trans european suture zone the presence of this fundamental crustal boundary may be paramount in structurally controlling the position of the mpt concentrating stresses during post variscan wrench and extensional tectonics in central europe tectonic subsidence analysis of the preserved and reconstructed stratigraphic record of the polish basin indicates the occurrence of an initial late permian early triassic 255 241 ma rifting phase that was followed by subsequent episodes of increased tectonic subsidence during the oxfordian kimmeridgian 157 152 ma and beginning in the cenomanian 97 ma the oxfordian kimmeridgian episode is interpreted as corresponding to a second extensional event which correlated with intersified rifting and wrench activity within the arctic north atlantic rift system and along the northern tethyan margin while the cenomanian may be considered a precursor of compressional deformations in the basin which culminated in basin inversion in the latest cretaceous and paleocene forward modelling results in view of existing geophysical interpretations which show the presence of a deep moho and a very velocity lower crustal layer beneath thempt suggest that permo mesozoic basic development may be related at least in part to the intrusion of mantle material into and densification of the lower crust rather than exclusively to crustal extension and thinning

unsaturated zone tritium and chlorine 36 profiles from southern australia their use as tracers of soil water movement in this paper we present seven unsaturated zone profiles of 36cl and three 3h profiles from southern australia all profiles show single peaks corresponding to high radionuclide fallout from nuclear testing in the 1950s and 1960s the profiles are used to estimate rates of water movement leading to recharge of the groundwater among these profiles is the first profile on which high concentrations of 36cl have been found below a 2 m depth in this profile 3h and 36cl peaks coincide in six of the seven profiles total 36cl fallout was found to be between 1 2 and 2 4 1012 atoms m 2 and is of similar magnitude to that found at similar latitudes in the northern hemisphere comparisons of soil water fluxes estimated with 3h 36cl and chloride are briefly discussed

a new chloride leaching approach to the estimation of diffuse recharge following a change in land use abstract a new approach has been developed to estimate the increase in groundwater recharge following land use modification the approach uses the degree of leaching of chloride to quantify soilwater drainage below the root zone which ultimately leads to groundwater recharge it is more general than similar previously reported techniques for analysing transient chloride profiles to infer recharge rates and hence has wider application we have applied the technique to a field situation in southern australia where clearing of native vegetation for agricultural production leads to large increases in groundwater recharge the examples serve to demonstrate the technique and some of the practical difficulties in the application of solutes techniques to recharge estimation

bedrock infiltration estimates from a catchment water storage based modeling approach in the rain snow transition zone summary estimates of bedrock infiltration from mountain catchments in the western u s are essential to water resource managers because they provide an estimate of mountain block recharge to regional aquifers on smaller scales bedrock infiltration is an important term in water mass balance studies which attempt to estimate hydrologic states and fluxes in watersheds with fractured or transmissive bedrock we estimate the a daily time series of bedrock infiltration in a small catchment in the rain snow transition zone in southwest idaho using the difference between measured stream discharge and modeled soil drainage the accuracy of spatial patterns in soil water storage are optimized rather than the more common approach of minimizing error in integrated quantities such as streamflow bedrock infiltration is estimated to be 289 mm 50 mm for the 2011 water year which is 34 12 of the precipitation 95 confidence soils on the southwest facing slope drain more often throughout the snow season but the northeast facing slope contributes more total soil drainage for the water year peaks in catchment soil drainage and bedrock infiltration coincide with rain on snow events

magma and sediment ii problems of interpreting palaeovolcanics buried in the stratigraphic column president9s anniversary address 1982 the preservation of volcanoes never more than partial involves a complex interaction of processes and these operate over periods of time which are often undervalued from a review of the relative rates of these processes it seems that short lived structures such as surtseyan ash rings may be preserved albeit in modified form around their whole circumference for larger composite volcanoes however growth and remoulding by activity is balanced by penecontemporaneous and later erosion in such a way that the central and most of the proximal zones are likely to be removed before they can be buried either by transported volcaniclastic or regional epiclastic sediments even the preservation of distal zones may be asymmetrical a one sided hinge line subsidence sedimentation model is therefore suggested to explain the elongate lens shaped aspects of the many extrusive piles known to lie approximately concordantly within stratigraphic sequences formed in both continental and littoral environments

integration of viscoplastic effects in a one dimensional constitutive model for ground response analysis during an earthquake strain rate effects affect both the stiffness and damping behaviour of soils yet existing constitutive models for ground response analysis are typically formulated within a r

water movement in desert soil traced by hydrogen and oxygen isotopes chloride and chlorine 36 southern arizona abstract understanding soil water movement is important for water resource management and for analyzing pollutant transport in the vadose zone seasonal variations in shallow soil profiles may have profound effects on deep soil water and solutes we have investigated seasonal soil water movement in the top meter of undisturbed desert soil in the southern arizona using 2 h 18 o cl and bomb 36 c1 six soil profiles were sampled from a young terrace holocene during 1991 to 1992 on a seasonal basis one soil profile was sampled from an older terrace latest pleistocene in october 1992 and one from a yet older fan surface late pleistocene in march 1992 the results indicate that repeated seasonal cyclic movement of soil water in the top 60 80 cm active zone tends to produce a consistent stable isotope composition for the soil water below the active zone in different seasons the deep 18 o on the oldest surface is about 6 heavier than on the younger surfaces probably resulting from greater evaporative loss due to the larger proportion of fines in the older soil this deep isotopic composition is closely related to the composition of the local average annual precipitation an annual average evaporation rate of 35 mm year 1 was estimated using a steady state diffusion model whereas the actual regional evapotranspiration rate is 175 250 mm year 1 this suggests that about 80 of the soil water is lost through transpiration and first stage evaporation before quasi steady state is reached the long term average infiltration rate below the active zone is about 4 mm year 1 for the younger terrace based on both chloride mass balance and bomb 36 cl and 0 02 mm year 1 for the older terrace and the fan surface based on chloride mass balance the correlation between the deep 18 o the reduction of downward flux and the surface age suggests that increasing soil development has resulted in a significant decrease of soil water infiltration and hence an increase in evaporation and surface runoff

identification of areas of recharge and discharge using landsat tm satellite imagery and aerial photography mapping techniques abstract aerial photographs ap and landsat tm colour composites were used to map the geomorphology geology and structures of the salt river system of western australia geomorphic features identified are sand plains dissected etchplain colluvium lateritic duricrust and rock outcrops the hydrogeomorphic units include streams lakes and playas palaeochannels and palaeodeltas the structural features are linear and curvilinear lineaments ring structures and dolerite dykes suture lines control the course of the main river channel permeable areas around the circular granitic plutons were found to be the main areas of recharge in the uplands recharge was also found to occur in the highly permeable areas of the sandplains discharge was shown to be primarily along the main drainage lines on the edge of the circular sandplains in depressions and in lakes the groundwater occurrence and hydrogeological classification of the recharge potential of the different units were used to classify the mapped areas into recharge and discharge zones the results also show that tm colour composites provide a viable source of data comparable with ap for mapping and delineating areas of recharge and discharge on a regional scale

elastic and large strain nonlinear seismic site response from analysis of vertical array recordings abstractstrong ground motions from the mw 6 6 2007 niigata ken chuetsu oki earthquake were recorded by a free field downhole array at a nuclear power plant site conditions consist of about 70 m of medium dense sands overlying clayey bedrock with groundwater located at 45 m ground shaking at the bedrock level had a geometric mean peak acceleration of 0 55g which reduced to 0 4g at the ground surface indicating nonlinear site response one dimensional ground response analysis of relatively weak motion aftershock data provides good matches of the observed resonant site frequencies and amplification levels provided small strain damping levels somewhat larger than those from laboratory tests are applied nonlinear ground response analyses of strong motion data using laboratory based modulus reduction and damping relations valid up to moderate strain levels 0 5 produce unrealistic strain localization at a velocity contrast a procedure is presented to more realistically represent the large strain por

strain rate effect on soil secant shear modulus at small cyclic strains the effects of the shear strain rate d dt on the secant shear modulus gs of three clays and three sands at small cyclic shear strain amplitudes c under simple shear loading conditions are described the amplitude c varied between 0 0003 and 0 02 and between 0 0002 and 0 04 s for all six soils gs increases with such that the gs versus log data plot approximately along a straight line the slope of this line is g strain rate shear modulus parameter while its normalized value g gs n g shear strain rate modulus factor for the clays tested g ranges between 2 5 and 7 5 mpa and n g between 2 0 and 11 5 for the sandy soils g ranges between 0 2 and 3 0 mpa and n g between 0 2 and 6 0 both g and n g decrease moderately with increasing c i e the largest g and n g were obtained at the smallest c for five soils the families of the normalized modulus reduction curves gs gmax log c were constructed such that each curve pertains to a constant it was found that ha

the late paleozoic felsic lava dominated large igneous province in northeast germany volcanic facies analysis based on drill cores in the deep subsurface of the northeast german basin products of extensive volcanism are present that formed during the waning phase of the variscan orogeny permian carboniferous boundary large volumes 48 000 km3 of dominantly felsic magma were emplaced in the northern foreland of the variscan mountains in a terrestrial semi arid environment most of these units were inferred by previous authors to represent the products of explosive volcanic eruptions such as ignimbrites however a detailed analysis of the volcanic texture and lithofacies association shows that most units are best interpreted as coherent lavas emplaced either as extrusive units or as shallow intrusions with important implications for the reconstruction of the paleo environment this study shows that detailed textural examination of drill cores provide important observations which can be applied as criteria for the interpretation of the mode of volcanic eruptions furthermore phenocryst logging and geochemical fingerprinting based on immobile element ratios can be employed for the classification and discrimination of individual emplacement units

magmatic flare up at the carboniferous permian boundary in the ne german basin revealed by shrimp zircon ages shrimp ages of 12 volcanic samples indicate intense magmatic activity to have occurred at the carboniferous permian boundary throughout much of the ne german basin rhyolitic crystal rich samples have been taken from quarries in the halle volcanic complex hvc and in the flechtingen ignimbrite and from drill cores of the kotzen mirow friedland and penkun areas ten samples yielded 206pb 238u ages between 302 and 297 ma 3 ma respectively which indicate that the magmatic activity took place concentrated in a relatively short time span throughout much of the ne german basin two hvc samples have ages of 307 and 294 ma this remarkably synchronous magmatic activity occurred during the initial phase of the basin development considering published volume estimates 48 000 km3 extrusion rates during this time period probably were in the order of 0 01 km3 a 1 implying magma production rates of 0 1 km3 a 1 the calc alkaline sio2 rich volcanic rocks originated from magmas that presumably formed during anatexis and subordinate magma mixing in an intra continental transtensional setting the basaltic magma which must have provided the thermal input into the lower crust probably formed during decompressional melting of lithospheric mantle fertilised by previous magmatic processes the dated volcanic rocks occur in three geotectonic provinces namely the a mid german crystalline rise which forms the northern part of the internal variscides the b external variscides and the variscan foreland which is considered as c eastern avalonia many of the old zircons found in the hvc samples reflect the magmatic activity of the mid german crystalline rise 325 400 ma however cadomian 500 650 ma and older gondwanian elements 1674 2373 ma are also present although the flechtingen and kotzen areas are located within the external variscides it seems more likely that the middle to lower crust that experienced anatexis formed part of the eastern avalonia plate overridden by the variscan front thus the old zircons found in flechtingen 350 and 538 ma and kotzen 345 ma but certainly those present in the penkun drill cores 1483 ma represent eastern avalonia tectonic history the anatectic magmas in the friedland area probably formed partly from baltic crust thrusted below eastern avalonia during the caledonian orogeny among the old zircons from the friedland samples in addition to proterozoic ages 1456 ma we found testimony of caledonian 443 ma and of clearly post caledonian 387 ma magmatism