information content of slug tests for estimating hydraulic properties in realistic high conductivity aquifer scenarios summary a recently developed unified model for partially penetrating slug tests in unconfined aquifers malama et al in press provides a semi analytical solution for aquifer response at the wellbore in the presence of inertial effects and wellbore skin and is able to model the full range of responses from overdamped monotonic to underdamped oscillatory while the model provides a unifying framework for realistically analyzing slug tests in aquifers with the ultimate goal of determining aquifer properties such as hydraulic conductivity k and specific storage s s it is currently unclear whether parameters of this model can be well identified without significant prior information and thus what degree of information content can be expected from such slug tests in this paper we examine the information content of slug tests in realistic field scenarios with respect to estimating aquifer properties through analysis of both numerical experiments and field datasets first through numerical experiments using markov chain monte carlo methods for gauging parameter uncertainty and identifiability we find that 1 as noted by previous researchers estimation of aquifer storage parameters using slug test data is highly unreliable and subject to significant uncertainty 2 joint estimation of aquifer and skin parameters contributes to significant uncertainty in both unless prior knowledge is available and 3 similarly without prior information joint estimation of both aquifer radial and vertical conductivity may be unreliable these results have significant implications for the types of information that must be collected prior to slug test analysis in order to obtain reliable aquifer parameter estimates for example plausible estimates of aquifer anisotropy ratios and bounds on wellbore skin k should be obtained if possible a priori secondly through analysis of field data consisting of over 2500 records from partially penetrating slug tests in a heterogeneous highly conductive aquifer we present some general findings that have applicability to slug testing in particular we find that aquifer hydraulic conductivity estimates obtained from larger slug heights tend to be lower on average presumably due to non linear wellbore losses and tend to be less variable presumably due to averaging over larger support volumes supporting the notion that using the smallest slug heights possible to produce measurable water level changes is an important strategy when mapping aquifer heterogeneity finally we present results specific to characterization of the aquifer at the boise hydrogeophysical research site specifically we note that 1 k estimates obtained using a range of different slug heights give similar results generally within 20 2 correlations between estimated k profiles with depth at closely spaced wells suggest that k values obtained from slug tests are representative of actual aquifer heterogeneity and not overly affected by near well media disturbance i e skin 3 geostatistical analysis of k values obtained indicates reasonable correlation lengths for sediments of this type and 4 overall k values obtained do not appear to correlate well with porosity data from previous studies

discrete plio pleistocene phases of tilting and counterclockwise rotation in the southeastern aegean arc rhodos greece early pliocene formation of the south aegean left lateral strike slip system the island of rhodos represents an uplifted block in the largely submerged southeastern aegean forearc it has a complex history of subsidence uplift and counterclockwise rotation during the plio pleistocene in response to the interplay between large scale geodynamic processes in this paper we present a new chronostratigraphic framework for the continental pliocene apolakkia basin of southwestern rhodos we combine these time constraints with recently published chronostratigraphic data from the marine plio pleistocene basins of northeastern rhodos to reconstruct rotational and vertical motions our palaeomagnetic results identify two rotation phases for rhodos c 10 9 6 counterclockwise ccw rotation between 3 8 and 3 6 ma and c 17 6 ccw rotation since 0 8 ma between these phases rhodos tilted to the se drowning the southeastern coast to a depth of 500 600 m between 2 5 and 1 8 ma then to the nw which resulted in the re emergence of the drowned relief between 1 5 and 1 1 ma we relate the rotations of rhodos to incipient formation of the south aegean sinistral strike slip system and the foundering of the rhodos basin the previously shown absence of messinian evaporites in the deep marine rhodos basin in combination with the 3 8 ma onset of ccw rotation of rhodos constrains the onset of the formation of the south aegean strike slip system between 5 3 and 3 8 ma the formation of this strike slip system is probably related to the interplay of oblique collision between the southeastern aegean region and the northward moving african plate the westward motion of anatolia gravitational spreading of the overthickened aegean lithosphere and the recently postulated southwestward retreat of the african subducted slab along a subduction transform edge propagator fault

selachians from the niobrara formation of the upper cretaceous coniacian of carrot river saskatchewan canada acid etching of a shell bed zone has enabled us to reclaim numerous fish remains for the niobrara formation coniacian of east central saskatchewan including teeth of the following new taxa odon

a pressure packer system for conducting rising head tests in water table wells abstract the pressure system developed for fully saturated well screens has been modified for conducting rising head tests in water table wells installed in highly permeable aquifers the pressure system consists of a compressed air source and 1 inch diameter pvc piping with a packer attached at the end the pressure system was evaluated in a series of rising head tests conducted in a well at a superfund site in new england the well was tested with slugs and with the pressure system within each technique estimates of hydraulic conductivity showed no difference comparison of hydraulic conductivity estimates between techniques slug test vs pressure test showed differences due to stratigraphy the interval tested using slug tests crossed two stratigraphic units the pressure system tested only one of these units we conclude that the pressure system may be used to characterize the vertical hydraulic conductivity distribution in a series of successive tests by changing the packer position and the screened interval tested

ichthyornis aves from the early turonian late cretaceous of alberta an isolated left humerus from the cretaceous toothed bird ichthyornis is described the fossil comes from the vimy member of the kaskapau formation at watino alberta and is early turonian in age the watino specimen is the oldest well authenticated record of ichthyornis and the oldest cretaceous skeletal fossil of a bird from the western hemisphere the wide geographic distribution of ichthyornis within the western interior of north america is in keeping with nomadic habits as inferred from strongly flying modern marine birds

multi level slug tests in highly permeable formations 2 hydraulic conductivity identification method verification and field applications abstract using the developed theory and modified springer gelhar sg model an identification method is proposed for estimating hydraulic conductivity from multi level slug tests the computerized algorithm calculates hydraulic conductivity from both monotonic and oscillatory well responses obtained using a double packer system field verification of the method was performed at a specially designed fully penetrating well of 0 1 m diameter with a 10 m screen in a sand and gravel alluvial aquifer msea site shelton nebraska during well installation disturbed core samples were collected every 0 6 m using a split spoon sampler vertical profiles of hydraulic conductivity were produced on the basis of grain size analysis of the disturbed core samples these results closely correlate with the vertical profile of horizontal hydraulic conductivity obtained by interpreting multi level slug test responses using the modified sg model the identification method was applied to interpret the response from 474 slug tests in 156 locations at the msea site more than 60 of responses were oscillatory the method produced a good match to experimental data for both oscillatory and monotonic responses using an automated curve matching procedure the proposed method allowed us to drastically increase the efficiency of each well used for aquifer characterization and to process massive arrays of field data recommendations generalizing this experience to massive application of the proposed method are developed

vertebrates from the middle late cenomanian la cabana formation asturias northern spain palaeoenvironmental and palaeobiogeographic implications article i nfo the asturian la cabana formation middle late cenomanian in age has yielded a rich and diverse assemblage of vertebrate microremains the fauna consists of both marine and continental forms including chimaeroids various selachians and actinopterygians chelonians crocodilians plesiosaurs pterosaurs sauropod dinosaurs and marine squamates this mixed assemblage of autochthonous coastal and allochthonous continental elements comes mainly from a transgressive lag occurring near the base of the formation it also contains some remains which are probably reworked from older middle cenomanian deposits palaeontological taphonomic and sedimentologic data indicate a shallow platform and marine lagoon with addition of some continental elements a comparison with the late cenomanian vertebrate assemblage of charentes southwestern france shows numerous similarities between both areas some taxa only known from asturias and charentes e g the aigialosaur carentonosaurus suggest that the opening bay of biscay may have constituted a palaeobiogeographic area characterized by endemism during the mid cretaceous

a new paraclupeid fish clupeomorpha ellimmichthyiformes from a muddy marine pro delta environment middle cenomanian dunvegan formation alberta canada a black marine mudstone in allomember a of the middle cenomanian dunvegan formation alberta yielded a well preserved deep bodied fish skeleton attributable to a new genus and species tycheroichthys dunveganensis in the paraclupeidae clupeomorpha ellimmichthyiformes this new taxon appears most closely related to members of the subfamily paraclupeinae which includes largely freshwater and estuarine or marginal marine species known from south and central america and china the dunvegan formation represents a large delta complex deposited in the western interior seaway at about 65 n where mean sea water temperature may have been about 10 c the specimen was found about 60 km from the contemporaneous shoreline and in life apparently inhabited a shallow muddy pro delta environment characterized by high turbidity and variable salinity the fish may have died when it was engulfed by brackish floodwater that also introduced suspended mud that rapidly buried the body preventing physical disarticula

middle turonian dinosaur paleoenvironments in the upper cretaceous kaskapau formation northeast british columbia the kaskapau formation is a mudstone dominated wedge up to 950 m thick that spans late cenomanian to middle turonian time the formation has a prominent wedge geometry and was deposited in the foredeep of the western canada foreland basin in outcrop in northeast british columbia nearshore sandstones are locally well developed and include rare wedges of nonmarine strata on quality creek near tumbler ridge 11 m of nonmarine strata contain abundant dinosaur tracks and the first in situ dinosaur bone reported from british columbia this site at a paleolatitude of about 67 n preserves a rare glimpse of turonian terrestrial environments during global eustatic highstand three main dinosaur habitats are recognized strandplain and beach ridge freshwater lake and brackish lagoon back beach sandstone has a relief of about 2 5 m interpreted as beach ridges sandy coals containing abundant dinosaur tracks represent inter ridge slough deposits overlying lake deposits comprising laminated muds with freshwa

paleobiogeography of the cretaceous western interior seaway of north america the vertebrate evidence abstract distribution patterns of marine vertebrates of the cretaceous western interior seaway of north america are analysed in a biogeographical context the analysis is based on fossil vertebrate assemblages from the following lower campanian localities 1 anderson river fauna n w t 2 pembina fauna southern manitoba 3 sharon springs fauna south dakota wyoming 4 niobrara fauna kansas 5 mooreville fauna alabama due to the cosmopolitan nature of many marine vertebrates relative abundance is used in preference to presence absence data in identifying faunal distribution patterns the analysis demonstrates the presence of two faunal subprovinces in the seaway the northern interior subprovince is characterized by a low diversity in all groups and is dominated by plesiosaurs hesperornithiforms and the mosasaur platecarpus the southern interior subprovince is characterized by a high diversity in all groups and is dominated by sharks turtles and the mosasaur clidastes these biogeographical subdivisions support the hypothesis of warm temperature and cool temperate zones in the seaway that have been proposed on the basis of invertebrate faunas

a middle cenomanian euselachian assemblage from the dunvegan formation of northwestern alberta a euselachian assemblage was recovered from the middle cenomanian dunvegan formation situated in northwestern alberta this assemblage is the most northern described within the western interior seaway and provides an important insight into the euselachian faunal diversity of this little known region of the seaway despite its high paleolatitude the assemblage contains a number of elasmobranch taxa including hybodus squalicorax archaeolamna cretodus dallasiella and cretoxyrhina the dunvegan assemblage also contains the first known reports from canada of the odontaspid shark johnlongia parvidens the cretoxyrhinid shark protolamna carteri and the ray pseudohypolophus mcnultyi this assemblage extends the northern geographical range of all taxa preliminary comparisons with other middle cenomanian western interior seaway assemblages show that the core composition of the dunvegan assemblage is remarkably similar to that of other time equivalent assemblages however conspicuously absent are species t

thrust loads and foreland basin evolution cretaceous western united states two dimensional modeling of loading during the formation of the idaho wyoming thrust belt shows that regional isostatic compensation by flexure of an elastic lithosphere is sufficient to control the formation of a foreland basin the flexural rigidity of the lithosphere is inferred to have been approximately 1023 nm 1030 dyne cm on the basis of palinspastic comparison of predicted downwarping due to the thrust plate loads to the shape of the sedimentary wedge on the west side of the cretaceous western interior seaway erosion of part of the uplifted thrust plates redistributed the load depositing it farther to the east thereby causing subsidence over a much wider area than could have been accomplished only by the loading by thrust plates paleotopography after major cretaceous thrust events was calculated the resulting mountainous terrain gentle alluvial plain and flat sea floor correspond well with the topography of the modern foreland thrust belt and basin system in the andes of south america and to paleogeographic reconstructions in the western united states thrust belt topography is controlled by the subsurface geometry of the thrust faults particularly the positions of ramp zones and by isostatic subsidence

late cretaceous campanian actinopterygian fishes from the kristianstad basin of southern sweden although a diverse range of aquatic vertebrates are documented from the upper cretaceous mid campanian marine strata of the kristianstad basin in southern sweden only chondrichthyans and marine amniotes have been described in detail to date in contrast coeval actinopterygians are virtually unreported yet their remains are extremely abundant at most sampled localities a comprehensive assessment of these fossils has identified the first late cretaceous actinopterygian fauna from the fennoscandian shield incorporating indeterminate lepisosteids the durophagous pycnodontid anomoeodus subclavatus the predatory pachycormid protosphyraena sp a large ichthyodectid pachyrhizodontids resembling pachyrhizodus the enchodontid enchodus cf gladiolus and indeterminate small teleosts these taxa are diagnosed mainly from isolated teeth and scales implying substantial taphonomic loss prior to burial moreover the prolific recovery of actinopterygian skeletal remnants in recent excavations suggests that historical collecting biases rather than ecological paucity have contributed to their under representation in the swedish cretaceous record palaeobiogeographically the kristianstad basin actinopterygians show compositional resemblance to assemblages from the northern european platform and the western interior seaway of north america advocating distributional communication across the boreal proto atlantic ocean

fossil marine actinopterygian fishes from the kaskapau formation upper cretaceous turonian near watino alberta turonian fossil marine fishes occur at several localities near watino alberta in sandstones and in shale concretions of the vimy member kaskapau formation the actinopterygian fossils in the san

correlation of physical surfaces bentonites and biozones in the cretaceous colorado group from the alberta foothills to southwest saskatchewan and a revision of the belle fourche second white specks formational boundary new allostratigraphic correlations in west central alberta show that flooding surfaces in the sunkay and basal vimy members of the blackstone formation can be traced eastward from burnt timber creek for 500 km to western saskatchewan and for 350 km northward into the dunvegan and kaskapau formations at burnt timber creek a miliammina manitobensis microfauna in the lowest 1 m of the sunkay member indicates equivalence to the westgate formation and an overlying 70 cm conglomerate is correlative with the fish scales formation overlying mudstones contain foraminifera of the verneuilinoides perplexus zone indicative of the middle cenomanian belle fourche formation the base of the second white specks formation as currently defined in core in eastern alberta equates in outcrop with the lower part of the sunkay rather than the base of the vimy member as previously thought the base of the second white specks formation should be placed about 35 m higher in the stratotype core a bentonite located 9 3 m

mid cenomanian vertebrate faunas of the western interior seaway of north america and their evolutionary paleobiogeographical and paleoecological implications abstract the western interior seaway wis was an epicontinental sea that extended north south through the middle of north america during the last half of the cretaceous linking the tethys sea to the south with the boreal paleo arctic ocean to the north aptian maastrichtian sedimentary deposits from the seaway crop out in the western interior basin of canada and the united states vertebrate remains are commonly well preserved and in certain stratigraphic units abundant the classic vertebrate fauna of the wis from the upper cretaceous niobrara chalk has been studied for 150 years but relatively little has been known of the seaway s earlier faunas until recent years studies of mid cenomanian vertebrate faunas particularly from lag deposits bonebeds and calcarenites in canada and the united states have significantly altered the previous picture of the overall biodiversity and biogeography of the wis during the mid cretaceous these mid cenomanian faunas include diverse fish assemblages of chondrichthyans cartilaginous fishes and osteichthyans bony fishes as well as various forms of tetrapods including marine turtles plesiosaurs and hesperornithiform and ichthyornithiform birds our compilation of faunas indicates that at least 70 vertebrate taxa are recorded from five mid cenomanian wis localities situated in alberta saskatchewan the black hills region of south dakota and wyoming kansas and colorado the faunas include 41 chondrichthyans 21 osteichthyans 10 non avian tetrapods and five avian taxa our study combined with previous faunal studies suggests that the combination of the following eight chondrichthyan species characterizes mid cenomanian time which has been referred to as the woodbinian age in the marine realm of north america ptychodus decurrens p occidentalis squalicorax curvatus cretodus semiplicatus carcharias amonensis c saskatchewanensis eostriatolamia tenuiplicatus and cretomanta canadensis this is the geologic time when non ptychodontid hybodonts became rare faunal components in most areas and when a number of other fish lineages particularly teleosts emerged and diversified many of these persisted into the early campanian or the niobrara age that followed the woodbinian therefore mid cenomanian time in the wis can also be characterized by the genesis of the niobraran fauna a significant radiation and diversification of fish taxa the five mid cenomanian wis localities highlighted in this study are separated by as much as 18 latitude a north south distance of more than 2300 km these faunas demonstrate some clinal trends such as more diverse faunas of benthic chondrichthyans mixed with dolichosaurid lizards to the south and a more diverse fauna of birds to the north however the faunas overall show strong taxonomic homogeneity particularly among many chondrichthyans that were cosmopolitan indicating that passage throughout the seaway as well as to both the boreal and tethys oceans was utilized these faunas also demonstrate high osteichthyan diversity in the northern waters of the wis which were once thought to have supported only a depauperate cold adapted fauna because of the surprisingly great diversity in vertebrate taxa ecosystem structure and dynamics of the wis during the mid cenomanian were unquestionably complex

large scale natural gradient tracer test in sand and gravel cape cod massachusetts 3 hydraulic conductivity variability and calculated macrodispersivities hydraulic conductivity k variability in a sand and gravel aquifer on cape cod massachusetts was measured and subsequently used in stochastic transport theories to estimate macrodispersivities nearly 1500 k measurements were obtained by borehole flowmeter tests and permeameter analyses of cores the geometric mean for the flowmeter tests 0 11 cm s is similar to that estimated from other field tests the mean for the permeameter tests 0 035 cm s is significantly lower possibly because of compaction of the cores the variance for the flowmeter 0 24 is also greater than that for the permeameter 0 14 geostatistical analyses applying negative exponential models with and without nuggets reveal similar spatial correlation structures for the two data sets estimated correlation scales range from 2 9 to 8 m in the horizontal and from 0 18 to 0 38 m in the vertical estimates of asymptotic longitudinal dispersivity b 35 0 78 m are similar in magnitude to that observed in the natural gradient tracer test 0 96 m previously conducted at this site

late cretaceous cenomanian to campanian paleoenvironmental history of the eastern canadian margin of the western interior seaway bonebeds and anoxic events abstract upper cretaceous strata in the pasquia hills of the northern manitoba escarpment eastern saskatchewan canada provide a detailed paleoenvironmental and sea level record of the eastern margin of the western interior seaway sediments deposited during the cenomanian turonian greenhorn marine cycle are dominantly black mudstones deposited in a stratified water column with bottom water anoxia recurrently reaching into the photic zone a middle cenomanian sea level lowstand event followed by transgression left a series of bonebeds within the belle fourche member of the ashville formation indicating a sedimentary environment starved of coarse siliciclastics maximum sea level resulted in the formation of limestone beds within the favel formation further favoured by reduced terrigenous sediment input compared to the western margin limestone sedimentation was followed by a phase of increased freshwater input under lower sea level conditions and reducing zoo and phytoplankton diversities during final greenhorn regression eastern saskatchewan probably turned into a restricted basin severely limiting marine circulation poor or absent benthic foraminiferal assemblages and biomarker analysis suggest prevailing watermass stratification throughout the cenomanian turonian transgressive regressive cycle this was caused either by a freshwater lid stratification of boreal and tethyan derived watermasses or both to various intensities affected by changing sea level basin oxygenation during niobrara time varies between localities along the eastern margin as documented by presence absence of benthic and planktic foraminifera

the use of electrical resistivity tomograms as a parameterization for the hydraulic characterization of a contaminated aquifer abstract hydraulic characterization of a contaminated aquifer is an important step in depollution processes because its hydraulic parameters control the choice and efficiency of the depollution protocol to be adopted the characterization presented in this article uses a 3d electrical resistivity imagery to identify the spatial heterogeneities of a contaminated aquifer under tidal influence indeed we use a 3d resistivity model as a source of information to parameterize the reconstruction of the hydraulic conductivity in 3d by inverting a set of hydraulic data acquired on the 13 monitored wells in response to two pumping tests this parameterization relies on the identification of the main electro facies in the resistivity model in the saturated zone which will then be exploited in the hydraulic characterization to find their corresponding hydraulic conductivity values this strategy of parameterization permits to reduce the number of the hydraulic conductivity parameters to be identified to eight hydro facies with a stochastic algorithm called the adaptive metropolis algorithm the hydraulic responses associated with the pumping tests are obtained once the natural effect of the tide is removed the hydraulic conductivity model has permitted to highlight the main heterogeneities in the aquifer in which the hydraulic conductivity is ranging between 10 4 6 10 2 8 m s this range of variability reveals the permeable and smooth character of the aquifer in which the presence of coarse sand and flint blocks enhances its transmissivity these permeable zones are electrically identified by resistive anomalies in the 3d electrical resistivity imaging

an organic geochemical study of cenomanian turonian sediments from the western interior seaway canada abstract bulk geochemical and biomarker data were collected for three cenomanian turonian late cretaceous sections in the western canada sedimentary basin western interior seaway canada rock eval and biomarker analyses indicate an east west thermal maturity trend due to progressive deeper burial associated with the tectonic flexure of the foreland basin the source of extractable organic matter is dominantly marine with a minor terrestrial contribution a pseudohomologous family of 2 2 dimethylalkanes 2 2 dmas in the c 16 c 28 range with an even number of carbon atoms exclusively was tentatively identified from mass spectral data in samples from the pasquia hills region easternmost section the specific origin of 2 2 dimethylalkanes remains unclear the presence of isorenieratene derivatives indicates that the northern part of the western interior seaway experienced photic zone euxinic events throughout the transgressive highstand and regressive phases of the greenhorn cycle the differential occurrence of isorenieratane between the canadian sections and the united states transect at maximum sea level high stand indicates that the water column of the northern part of the wis was less oxygenated whereas the water column in the southern wis was more dynamic and well mixed