non trionychid turtles from the paleocene of alberta canada turtle fossils of paleocene age have been recovered from four formations in alberta canada the upper paleocene part of the scollard formation the upper paleocene portion of the willow creek formation and the exclusively paleocene porcupine hills and paskapoo formations at least three non trionychid turtle taxa can be recognized definitely present are a generically indeterminate baenid the macrobaenid judithemys backmani and the chelydrid protochelydra zangerli the carapace of a juvenile chelydrid could be either a juvenile of p zangerli or a fourth distinct taxon the macrobaenid j backmani and the chelydrid p zangerli are the most abundant non trionychid turtles from the paleocene of alberta the turtles from the paleocene of alberta differ from those of comparable age in new mexico usa and other more southern localities in the north american western interior in i the presence of macrobaenids and chelydrids and ii the absence of kinosternoids these differences mirror those of the

zonal flow stationary wave relationship during el nino implications for seasonal forecasting abstract an analysis of the northern hemispheric zonal mean flow anomalies during el nino is performed and the dynamical effect of such atmospheric flows on the wintertime climatological stationary waves over the pacific north american pna region is assessed only in the subtropical latitudes can one identify a statistically significant zonal flow anomaly during the el ni os of the historical record strong zonal flow anomalies in the midlatitudes are observed during individual el ni o events although these appear to be manifestations of chaotic atmospheric behavior the observational results are confirmed by gcm climate simulations using prescribed ssts for the 1982 93 period the principal sst forced zonal flow signal in these experiments is located on the equatorward flank of the subtropical jet using a linear diagnostic modes the authors find the climatological stationary waves over the pna region to be insensitive to zonal mean flow anomalies in the subtropics on the other hand zonal mean ano

the significance of the theropod collections of the royal tyrrell museum of palaeontology to our understanding of late cretaceous theropod diversity1 significant specimens of theropod dinosaurs were part of the collections that were transferred to the royal tyrrell museum of palaeontology when it split off from the provincial museum of alberta in 1981 collecting activity of the institution increased dramatically in the period leading up to the opening of the building and displays in 1985 and resulted in the recovery and preparation of many fine theropod skeletons new specimens have been added to the collection every year since the museum opened several mostly small taxa are only represented by isolated bones partial skeletons and or teeth theropod specimens also include footprints coprolites eggs and feathers in amber although theropods are relatively rare in comparison with herbivorous dinosaurs the tyrrell has managed to build one of the finest research collections of late cretaceous forms thirty seven species of theropods in the tyrrell are currently accepted as being valid of which 30 are from the upper cretaceous deposits of alberta

vertebrate fossils dinosauria from the bonnet plume formation yukon territory canada dinosaurs and other terrestrial vertebrates are poorly documented in the mesozoic of the canadian polar region here we provide a complete review of the upper cretaceous maastrichtian vertebrate fauna of the bonnet plume formation in the northeastern yukon territory canada which includes the description of the first newly collected dinosaur bones from this unit in almost half a century previously reported fragmentary dinosaur remains collected in the early 1960 s pertain to an indeterminate hadrosaurid new material includes a poorly preserved forelimb bone and a pedal phalanx these new remains pertain to at least one species of non hadrosaurid ornithischian dinosaur and the humerus is tentatively referred to a small bodied basal ornithopod the new vertebrate fossils from the bonnet plume formation provide further evidence of vertebrates from this unit however directed field surveys in 2008 and 2009 suggest that vertebrate fossils are not abundant a review of the known localities of terrestrial mesozoic vertebrates from the canadian arctic indicate that it had a relatively diverse community of terrestrial vertebrates including dinosaurs during the late cretaceous but emphasizes our limited knowledge of the mesozoic arctic and considerable potential for future exploration and discovery

maintenance of northern summer stationary waves in a gcm abstract the maintenance of northern summer stationary waves is studied with data from a 15 year integration of the general circulation model gcm experiment performed at the geophysical fluid dynamics laboratory the model has relatively high resolution rhomboidal 30 wavenumbers 9 vertical levels and simulates the summertime stationary waves reasonably well a steady linear baroclinic model is used to understand the various forcing mechanisms for the northern summer stationary waves the linear model response to global diabatic heating is found to play a dominant role in maintaining the summertime stationary waves in the gcm especially in the subtropics this response to diabatic heating shows a baroclinic structure in the vertical with a node at about 0 5 on the other hand stationary nonlinear interaction terms are found to be largely responsible for the extratropical equivalent barotropic stationary wave features it is hypothesized that this nonlinear interaction is a result of the therm

calibration and validation of reservoir models the importance of high resolution quantitative outcrop analogues rapidly developing methods of digital acquisition visualization and analysis allow highly detailed outcrop models to be constructed and used as analogues to provide quantitative information about sedimentological and structural architectures from reservoir to subseismic scales of observation terrestrial laser scanning lidar and high precision real time kinematic gps are key survey technologies for data acquisition 3d visualization facilities are used when analysing the outcrop data analysis of laser scan data involves picking of the point cloud to derive interpolated stratigraphic and structural surfaces the resultant data can be used as input for object based models or can be cellularized and upscaled for use in grid based reservoir modelling outcrop data can also be used to calibrate numerical models of geological processes such as the development and growth of folds and the initiation and propagation of fractures

new information on shanshanosaurus huoyanshanensis a juvenile tyrannosaurid theropoda dinosauria from the late cretaceous of china shanshanosaurus huoyanshanensis from the subashi formation upper cretaceous of xinjiang in northwestern china has long been thought of as a distinctive genus of small theropod although usually assigned to its own family it has generally been included in the tyrannosaurid subfamily aublysodontinae in recent years restudy and description of the only known specimen reveal that it is not a small species but is a juvenile tyrannosaurine possibly tarbosaurus with a total estimated length of 2 3 m it is the smallest tyrannosaurid skeleton known shanshanosaurus provides the best information available on ontogenetic changes in these enormous carnivores and reveals that young tyrannosaurids had long low skulls huge pubic boots and well developed limb joints evidence suggesting that young tyrannosaurs had relatively longer forelimbs than the adults is not supported by shanshanosaurus

albanerpetontid amphibians from the late cretaceous santonian of iharkut hungary with remarks on regional differences in late cretaceous laurasian amphibian assemblages since its discovery in 2000 the iharkut fossil locality in the upper cretaceous santonian csehbanya formation of western hungary has yielded a taxonomically diverse assemblage of terrestrial and freshwater vertebrates that continue to provide insights into the diversity paleobiogeography and paleoecology of late cretaceous vertebrates in europe albanerpetontidae an extinct group of superficially salamander like amphibians that were widespread across laurasia during the latter part of the mesozoic are represented at iharkut by 16 fragmentary jaws here we describe and figure these specimens as albanerpetontidae genus and species indeterminate based on the age of the iharkut locality several premaxillary features the known distribution late early cretaceous late pliocene of the type genus albanerpeton and an unusually large dentary specimen we suggest that the iharkut albanerpetontid may pertain to a previously unrecognized species of albanerpeton but verification of that must await the re

multiscale diagnosis of the north american monsoon system using a variable resolution gcm abstract the onset and evolution of the north american monsoon system during the summer of 1993 were examined from regional to large scales using the national aeronautics and space administration nasa goddard earth observing system geos stretched grid gcm the model s grid spacing for the dynamical core ranges from 0 4 0 5 in latitude longitude over the united states to about 2 5 3 5 at the antipode and the physical package is solved on an intermediate 1 1 uniform grid a diagnostic analysis of the monsoon s onset reveals the development of a positive potential temperature anomaly at the surface that favors a lower level cyclonic circulation while a negative potential vorticity pv anomaly below the tropopause induces an upper level anticyclonic circulation ignoring diabatic effects this pattern is consistent with the superimposition of idealized pv and anomalies as previously discussed in the literature the inclusion of the smaller scale features of the core monsoon in the mod

the east atlantic west russia ea wr teleconnection in the north atlantic climate impact and relation to rossby wave propagation large scale winter teleconnection of the east atlantic west russia ea wr over the atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence a rotated empirical orthogonal function analysis of the upper tropospheric monthly height field captures successfully the ea wr pattern and its interannual variation with the north atlantic oscillation nao as the first mode ea wr s climate impact extends from eastern north america to eurasia the positive negative ea wr produces positive negative temperature anomalies over the eastern us western europe and russia east of caspian sea with negative positive anomalies over eastern canada eastern europe including ural mountains northeastern africa and the middle east these anomalies are largely explained by lower tropospheric temperature advections positive negative precipitation anomalies are found over the mid latitude atlantic and central russia around 60 e where lower level cyclonic anticyclonic circulation anomaly is dominant eastern canada and western europe including the mediterranean region are characterized by negative positive precipitation anomalies the ea wr is found to be closely associated with rossby wave propagation wave activity fluxes show that it is strongly tied to large scale stationary waves furthermore a stationary wave model swm forced with vorticity transients in the mid latitude atlantic 40 n or diabatic heat source over the subtropical atlantic near the caribbean sea produces well organized ea wr like wave patterns respectively sensitivity tests with the swm indicate enhancement of ea wr like blocking over west of scandinavia when the mean state is modified to have a positive nao component that enhances upper level westerlies between 40 and 60 n

an edentulous frog lissamphibia anura from the upper cretaceous campanian dinosaur park formation of southeastern alberta canada the frog tyrrellbatrachus brinkmani gen et sp nov is described on the basis of seven incomplete maxillae from vertebrate microfossil localities in the upper cretaceous campanian dinosaur park formation in the dinosaur provincial park area southeastern alberta canada the maxillae are distinctive in a unique suite of features related to size shape and proportions of the bone texture of the labial surface form of the surface for inferred contact with the squamosal form of the lamina horizontalis and the processus pterygoideus relative depth of the crista dentalis and in being edentulous i e lacking teeth the higher level affinities of tyrrellbatrachus are uncertain although certain features exclude it from several known families for example the presence of a processus pterygoideus excludes it from gobiatidae late cretaceous asia whereas the presence of a crista dentalis and of a relatively unreduced pars facialis exclude it from pipidae cretaceous recent africa and south ameri

physical processes involved in the 1988 drought and 1993 floods in north america abstract an analysis of the spring summer 1988 drought and 1993 floods over north america reveals a reversal in the sign of anomalies in several fields large sea surface temperature anomalies of opposite signs existed in the tropical pacific with strong la nina conditions in 1988 and a mature el nino in 1993 the distribution of tropical convection in the convergence zones and associated latent heating of the atmosphere were correspondingly altered implying a large scale switch in the anomalous tropical heating and forcing of extratropical quasi stationary waves in the atmosphere influencing the subtropical jet stream over the north pacific and across north america in 1988 the jet stream and the closely related storm track of high frequency disturbances in the upper troposphere were displaced into canada well north of the normal location the farthest north of any year from 1979 to 1993 in 1993 a broader jet stream and the storm track were displaced well south of normal to a more springlike location a

dinosaur footprints with skin impressions from the cretaceous of alberta and colorado cretaceous dinosaur footprints discovered in the j sandstone of the south platte formation dakota group in colorado and the st mary river formation of southwestern alberta exhibit the first repo

ordosemys leios n gen n sp a new turtle from the early cretaceous of the ordos basin inner mongolia ordosemys leios n gen n sp from the early cretaceous luohandong formation zhidan group ordos basin inner mongolia is a primitive aquatic turtle with a reduced fenestrated plastron it shares with the members of the centrocryptodira the presence of well formed articular surfaces on the cervical and caudal vertebrae within the centrocryptodira characters of the cervical vertebrae suggest it is more closely related to the polycryptodira than is the meiolaniidae ordosemys shares with the chelydridae the presence of two procoelous anterior caudals but this character may be primitive for the polycryptodira characters of the basicranial region of the braincase shared by ordosemys and the chelonioidea support a sister group relationship between these two taxa but a sister group relationship between ordosemys and the polycryptodira is more strongly supported by characters shared by the chelonioidea and other members of the polycryptodira

characteristics of summer stationary waves in the northern hemisphere abstract summer stationary waves in the northern hemisphere are separated by a midlatitude transition zone into the subtropical monsoon regime with a vertical phase reversal and the subarctic regime with a vertically uniform structure the dynamics and maintenance mechanism of the subtropical stationary waves have been investigated in the context of monsoon circulation depicted in terms of streamfunction with 40 yr ecmwf re analysis era 40 the dynamic characteristics of stationary waves in the transition zone and the subarctic region are thus the focus of this study the dynamics and maintenance mechanism of these waves were explored with the streamfunction budget and the velocity potential maintenance equations stationary waves across the transition region consist of anticyclonic shear zones over the north pacific and north atlantic and a cyclonic shear zone in east eurasia these transition elements are linked to subtropical oceanic anticyclones and continental thermal lows at high latitudes a th

a new specimen of utatsusaurus reptilia ichthyosauria from the lower triassic sulphur mountain formation of british columbia an incomplete skull and mandible of the primitive ichthyosaur utatsusaurus is described from the lower triassic vega phroso member of the sulphur mountain formation of british columbia the specimen contributes to our knowledge of the cranial anatomy of the genus which was previously known primarily from postcranial material and extends its geographic range to canada the presence of an isodont dentition in this primitive genus suggests that isodonty rather than heterodonty may be the primitive character state for the ichthyosauria

factors determining the extratropical response to equatorial diabatic heating anomalies abstract the steady linear response of a spherical baroclinic atmosphere to an equatorial diabatic heat source having a simple horizontal and vertical structure is examined this source is imposed upon representative zonally symmetric as well as zonally varying flows during the boreal winter two climatologies are considered one is a 6 year average of global observations analyzed at the european centre for medium range weather forecasts ecmwf the other is a 30 year average taken from a general circulation model gcm run at the geophysical fluid dynamics laboratory in princeton the extratropical response is found to be very sensitive to the basic state around which the governing primitive equations are linearized and in the case of the ecmwf climatology to the longitudinal position of the source with respect to the climatological waves there is also some sensitivity to the vertical level of maximum heating although again this is more evident in the case of the ecmwf basic state these results ar

a new species of zangerlia testudines nanhsiungchelyidae from the upper cretaceous redbeds at bayan mandahu inner mongolia and the relationships of the genus zangerlia neimongolensis sp nov is described on the basis of material from the upper cretaceous redbeds at bayan mandahu in inner mongolia zangerlia neimongolensis is similar to zangerlia testudinimorpha in the proportions of the carapace and plastron and presence of a knob at the posterior end of the neural series but differs from it in the arrangement of scutes covering the bridge the placement of zangerlia in the nanhsiungchelyidae is supported by derived features of the bridge peripherals and plastral scutes shared by z neimongolensis basilemys and nanhsiungchelys these are the presence of ventrally expanded sixth inframarginal scutes humeral scutes that are narrow at the midline and expanded laterally pectoral scutes that are wide at the midline and narrow laterally and large rectangular abdominal scutes the skull of zangerlia is more primitive than that of nanhsiungchelys the only other member of the family for which a skull is known it shows extensive emargination of the temporal and

teleconnections associated with northern hemisphere summer monsoon intraseasonal oscillation the boreal summer intraseasonal oscillation bsiso has strong convective activity centers in indian i western north pacific wnp and north american na summer monsoon sm regions the present study attempts to reveal bsiso teleconnection patterns associated with these dominant intraseasonal variability centers during the active phase of ism a zonally elongated band of enhanced convection extends from india via the bay of bengal and philippine sea to tropical central pacific with suppressed convection over the eastern pacific near mexico the corresponding extratropical circulation anomalies occur along the waveguides generated by the north african asian jet and north atlantic north european jet when the tropical convection strengthens over the wnpsm sector a distinct great circle like rossby wave train emanates from the wnp to the western coast of united states us with an eastward shift of enhanced meridional circulation in the active phase of nasm large anticyclonic anomalies anchor over the western coast of us and eastern canada and the global teleconnection pattern is similar to that during a break phase of the ism examination of the evolution of the bsiso teleconnection reveals quasi stationary patterns with preferred centers of teleconnection located at europe russia central asia east asia western us and eastern us and canada respectively most centers are embedded in the waveguide along the westerly jet stream but the centers at europe and russia occur to the north of the jet induced waveguide eastward propagation of the iso teleconnection is evident over the pacific north america sector the rainfall anomalies over the elongated band near the monsoon domain over the indo western pacific sector have an opposite tendency with that over the central and southern china mexico and southern us providing a source of intraseasonal predictability to extratropical regions the bsiso teleconnection along and to the north of the subtropical jet provides a good indication of the surface sir temperature anomalies in the nh extratropics

a new genus of ichthyosaur from the late triassic pardonet formation of british columbia bridging the triassic jurassic gap both the genus shastasaurus and the family shastasauridae have long been hard to define due to the fragmentary nature of the type specimens consequently recent interpretations of the genus have been based almost entirely on shastasaurus neoscapularis from the late triassic pardonet formation of british columbia two new specimens of this taxon from pink mountain british columbia demonstrate that it does not belong in the genus shastasaurus this paper describes the new specimens and refers the species to metashastasaurus gen nov post cranially the skeleton of metashastasaurus resembles that of shastasaurids differing primarily only in the shape of the scapula and fibula however the skull has a unique combination of characters including large diamond shaped frontals that enter the supratemporal fenestrae and very narrow posterior extensions of the nasals which contact the postfrontals it also differs from the skull of shastasaurus in the presence of both a parietal ridge and postparietal she

three dimensional imaging of a deep marine channel levee overbank sandstone behind outcrop with emi and gpr deepwater channel levee overbank sandstones are important sources of oil and gas but their internal stratigraphy is complex and not well understood one means to better characterize this complex stratigraphy is through the study of outcrops such as the dad sandstone member of the lewis shale figure 1 in carbon county wyoming u s pyles and slatt 2000 figure 1 top the outcrop of the dad sandstone member of the lewis shale a series of channel fill sandstones dip toward the lower right west the lowermost sandstone is the subject of this study this sandstone trends along the outcrop face toward the lower right but is juxtaposed against shale toward the west at the same stratigraphic level the gpr line on the lower left of the figure modified from young et al 2003 shows the base of the channel fill sandstone red line where it intersects the ground surface northwest of the base of the sandstone at equivalent radar times the lithology is shale the lower right figure shows the emi volume in plan view with sandstone in yellow and shale in gray note the bend in the sandstone at the location where the channel base intersects the ground surface channel levee overbank systems are a result of multiple sediment gravity flows the channel itself is formed from aggradation of levees over long periods of time as sediment flows within the channel fine particles are expelled over the channel edges thus forming the levees coarser particles not deposited on the levee are transported beyond the channel to form frontal splays or lobes sediment may slump off the levee walls onto the channel floor during this time interval channels are later backfilled with sand and or mud as transport energy diminishes probably during an early rise in sea level the materials that fill the channel can be configured in different arrangements

first report of protoceratopsians neoceratopsia from the late cretaceous judith river group alberta canada protoceratopsians are best known in north america from associated skeletal material of montanoceratops from the early maastrichtian of montana and campanian of alberta and leptoceratops from the la

reinterpretation of middle cambrian stratigraphy of the rifted western laurentian margin burgess shale formation and contiguous units sauk ii megasequence rocky mountains canada abstract until recently research on the renowned fossil animals of the burgess shale has advanced to a greater degree than an understanding of the rocks in which they are found studies addressing lithostratigraphy and hydrothermal petrography of the so called inner carbonate belt and adjacent chancellor group however have begun to re evaluate long standing hypotheses on the middle cambrian of western canada tectonic activity along the kicking horse rim buried remnants of neoproterozoic rifting during the cambrian period had more influence on local sedimentation than previously thought notably large scale collapse of the cathedral carbonate platform margin at 509 ma bp is evidence of reactivated basement faults these failures produced listric megatruncation surfaces having near vertical escarpments 150 m in height where they terminate against the platform the majority of what have been interpreted as shed olistoliths from the cathedral platform margin is herein shown instead to be carbonate mud mounds these grew in situ along the face of the cathedral escarpment and are associated with fossiliferous intervals in overlying basinal mudstones at three distinct stratigraphic horizons two within the burgess shale during the delamaran and marjuman stages the mounds nucleated where deep seated normal faults intersected the seafloor building primarily during periods of relative sea level transgression mound growth is associated with syndepositional exhalative activity inferred from stratigraphic relations sedimentology and geochemistry the new name monarch formation is proposed for the initial post collapse beds and mounds deposited against the cathedral escarpment early glossopleura zone the variably defined term takakkaw tongue is thereby confined to pre collapse slope deposits coeval to and correlative with the cathedral formation

northern hemisphere teleconnection patterns during extreme phases of the zonal mean circulation abstract regional climate anomalies associated with year to year changes in the tropospheric zonal mean zonal wind are examined this study focuses on the wintertime northern hemisphere extratropics and compares seasonal mean anomalies associated with to those associated with the el nino southern oscillation during the 1947 94 period dynamical model experiments indicate that a single zonal index characterized by out of phase anomalies at 35 and 55 n is of primary importance for zonal flow stationary wave interactions in the northern hemisphere extratropies such fluctuations in the zonal mean zonal flow are shown to occur independently of tropical sst variability consistent with earlier studies dynamical model experiments and regression analyses of the historical data indicate that such a zonal index explains a significant fraction of the wintertime stationary wave variability in several regions the principal centers of action reside within wave trains over the north pacific north american

acoustic and petrophysical properties of a clastic deepwater depositional system from lithofacies to architectural elements scales an analysis of acoustic petrophysical and stratigraphic heterogeneities has been completed at three scales for an outcropping subcropping deep water stratigraphic sequence lithofacies core plug lithostratigraphic unit well log and architectural element seismic measurement techniques instruments included outcrop measured sections behind outcrop drilling logging coring and subsequent core and log analysis ground penetrating radar shallow seismic reflection and electromagnetic induction at the lithofacies scale four rock types are defined 1 heterogeneous sandstones and 2 uniform sandstones which differ in their grain composition and sedimentary structures but do not differ significantly in average porosity permeability and acoustic impedance and 3 organic rich shales and 4 organic poor shales which exhibit significantly higher acoustic impedance than either sandstone type there is an inverse relation between porosity and permeability versus acoustic impedance ofthe lithofa

hesperornis aves from ellesmere island and palynological correlation of known canadian localities a tarsometatarsus of hesperornis from the kanguk formation on ellesmere island is described and illustrated and constitutes the northernmost occurrence of the genus palynological evidence and stra

djadokhta formation correlative strata in chinese inner mongolia an overview of the stratigraphy sedimentary geology and paleontology and comparisons with the type locality in the pre altai gobi because the bayan mandahu redbeds of inner mongolia share similar sedimentary facies and fossil assemblages with the djadokhta formation of pre altai gobi the two units are interpreted as stratigr

extraordinary preservation in a new vertebrate assemblage from the late cretaceous of mongolia we report here a new locality ukhaa tolgod brown hills from the upper cretaceous of the gobi desert of mongolia which shows an unmatched abundance of well preserved vertebrate fossils including the highest concentration of mammalian skulls and skeletons from any mesozoic site in the main collecting area about 4 km2 recovered and uncollected articulated skeletons of thero pod ankylosaurian and protoceratopsian dinosaurs represent over 100 individuals specimens collected also include skulls many with associated skeletons of over 400 mammals and lizards skeletons including the first known skull of the bird mononykus and nest sites that preserve the first known theropod dinosaur embryos1 in contrast to other mesozoic localities the diversity and abundance of theropods mammals and lizards are unusually high the exceptional preservation of vertebrates from the red bed facies of the gobi upper cretaceous has been attributed to arid conditions2 4 possibly involving catastrophic death and burial during major sandstorms5 although fossils are found in fluvial facies at ukhaa tolgod high concentrations of excellent specimens in aeolian facies support the argument for rapid entombment in sand this contrasts with conditions for the terrestrial upper cretaceous in north and south america where accretionary preservation of fossils in fluvial deposits predominates

a new articulated freshwater fish clupeomorpha ellimmichthyiformes from the horseshoe canyon formation maastrichtian of alberta canadathis article is one of a series of papers published in this special issue on the theme albertosaurus horseshoeichthys armaserratus gen et sp nov clupeomorpha ellimmichthyiformes sorbinichthyidae is described from the horseshoe canyon formation maastrichtian albertosaurus bonebed locality alberta canada horseshoeichthys armaserratus is classified as an ellimmichthyiform based on the following characters the presence of a sixth infraorbital with a sensory canal that leads to the fifth infraorbital absence of a supraorbital bone subrectangular predorsal scutes parietals in contact with each other at the midline and two supramaxillae the specimen is classified in the sorbinichthyidae family as it has abdominal ribs articulating in pits on the centra posterior spines on predorsal scutes and absence of a median spine on predorsal scutes a new genus and species is proposed based on the presence of anteriorly y shaped mesethmoid supraorbital subrectangular predorsal scutes with coarse rounded serrae on the posterior margin and a large anterior projection scales with serrae on the ci

marine turtles from the late cretaceous of alberta canada previously reported and new specimens of marine turtles from the late campanian of alberta canada provide additional information on the diversity and distribution of chelonioid turtles at this time an articulated carapace from the bearpaw formation previously interpreted as lophochelys niobrarae is considered to be a juvenile of a specifically indeterminate chelonioid and is referred to lophochelys sp isolated neurals and a hyoplastron from nonmarine estuarine deposits in the uppermost beds of the dinosaur park formation are tentatively referred to lophochelys sp these specimens suggest that this chelonioid could enter freshwater environments a new chelonioid kimurachelys slobodae gen et sp nov is recognized on the basis of two mandibles and a maxilla from the uppermost beds of the dinosaur park formation of southeastern alberta a partial postcranial skeleton of an indeterminate chelonioid from the bearpaw formation provides additional evidence that chelonioids of this formation included taxa that were phylogenetically intermediate between chelonioids of the late santonian and members of the crown group

the regional forcing of northern hemisphere drought during recent warm tropical west pacific ocean la nina events northern hemisphere circulations differ considerably between individual el nino southern oscillation events due to internal atmospheric variability and variation in the zonal location of sea surface temperature forcing over the tropical pacific ocean this study examines the similarities between recent northern hemisphere droughts associated with la nina events and anomalously warm tropical west pacific sea surface temperatures during 1988 1989 1998 2000 2007 2008 and 2010 2011 in terms of the hemispheric scale circulations and the regional forcing of precipitation over north america and asia during the cold season of november through april the continental precipitation reductions associated with recent central pacific la nina events were most severe over north america eastern africa the middle east and southwest asia high pressure dominated the entire northern hemisphere mid latitudes and weakened and displaced storm tracks northward over north america into central canada regionally over north america and asia the position of anomalous circulations within the zonal band of mid latitude high pressure varied between each la nina event over the northwestern and southeastern united states and southern asia the interactions of anomalous circulations resulted in consistent regional temperature advection which was subsequently balanced by similar precipitation modifying vertical motions over the central and northeastern united states the spatial variation of anomalous circulations resulted in modest inter seasonal temperature advection variations which were balanced by varying vertical motion and precipitation patterns over the middle east and eastern africa the divergence of moisture and the advection of dry air due to anomalous circulations enhanced each of the droughts

warm season subseasonal variability and climate extremes in the northern hemisphere the role of stationary rossby waves abstractthis study examines the nature of boreal summer subseasonal atmospheric variability based on the new nasa modern era retrospective analysis for research and applications merra for the period 1979 2010 an analysis of the june july and august subseasonal 250 hpa meridional wind anomalies shows distinct rossby wave like structures that appear to be guided by the mean jets on monthly subseasonal time scales the leading waves the first 10 rotated empirical orthogonal functions reofs of the 250 hpa wind explain about 50 of the northern hemisphere wind variability and account for more than 30 60 of the precipitation surface temperature variability over a number of regions of the northern middle and high latitudes including the u s northern great plains parts of canada europe and russia the first reof in particular consists of a rossby wave that extends across northern eurasia where it is a dominant contributor to monthly surface temperature and precipitation variability and

origins of dinosaur bonebeds in the cretaceous of alberta canada upper cretaceous dinosaur bonebeds are common in alberta canada and have attracted continuous scientific attention since the 1960s since its inception the royal tyrrell museum of palaeontology has documented the presence of hundreds of these sites and has been involved directly in the scientific study of many tens because many of these bonebeds have been used to address questions about the paleobiology and paleoecology of dinosaurs questions have arisen about bonebed origins and preservation in the cretaceous of alberta this study of 260 bonebeds delineates broad paleoenvironmental settings and associations and taphonomic signatures of assemblages as a first step in assessing patterns of dinosaur bonebed origins in the upper cretaceous of alberta bonebeds are known predominantly from the belly river group and the horseshoe canyon lower st mary river wapiti and scollard formations in these units bonebeds are mostly associated with river channel and alluvial wetland settings that were influen

is midlatitude convection an active or a passive player in producing global circulation patterns abstract the ability of persistent midlatitude convective regions to influence hemispheric circulation patterns during the northern hemisphere summer is investigated global rainfall data over a 15 yr period indicate anomalously large july total rainfalls occurred over mesoscale sized midlatitude regions of north america and or southeast asia during the years of 1987 1991 1992 and 1993 the anomalous 200 hpa vorticity patterns for these same years are suggestive of rossby wave trains emanating from the regions of anomalous rainfall in the midlatitudes results from an analysis of an 11 yr mean monthly 200 hpa july wind field indicate that in the climatological mean rossby waveguides are present that could assist in developing a large scale response from mesoscale sized regions of persistent convection in the midlatitudes this hypothesis is tested using a barotropic model linearized about the 200 hpa july time mean flow and forced by the observed divergence anomalies the model results are in qualit

second known occurrence of the early paleocene plesiadapiform pandemonium mammalia primates with description of a new species pandemonium hibernalis sp nov from a middle puercan earliest paleocene locality in the upper scollard formation wintering hills southern alberta represents the second discovered occurrence of the enigmatic plesiadapiform primate pandemonium van valen and the first from canada the holotype of pandemonium hibernalis is the only known specimen of pandemonium documented by multiple teeth from a single individual pandemonium hibernalis closely resembles the type species pandemonium dis from purgatory hill middle late puercan tullock formation montana but differs in having wider more bunodont lower molar crowns and a more expanded posterior talonid lobe of m3 specializations suggesting enhanced capacity for crushing and grinding of soft food materials during mastication pandemonium hibernalis joins other recent discoveries in alberta and elsewhere in the north american western interior in documenting a moderate radiation of basal plesiadapiforms that evolved unexpectedly early during primate e

physical mechanisms of the 1993 summer floods abstract the physical mechanisms responsible for the onset and maintenance of the 1993 summer floods were examined using the localized eliassen palm flux diagnostics and solutions of a single level primitive equation model linearized about a meridionally varying basic state the unusually long persistent summer pattern is linked with the marked transient eddy activity in late may and june the feedback of eddies in the time mean flow caused a strengthening and eastward extension of the pacific jet and a strengthening of the jet over north america results from the model suggest that the summer pattern may be interpreted as that of a lee trough forced by the rocky mountains in the presence of a strong westerly mean flow maintained by the eddies upstream composites from cases similar to that of the 1993 summer exhibit strong low level southerly flow cast of the rockies and suggest that the low level jet may be an important mechanism to sustain the anomalous rainfall it is concluded that the effect of the

maintenance of circulation anomalies during the 1988 drought and 1993 floods over the united states the large scale circulation anomalies associated with the 1988 drought and the 1993 floods are investigated with the national centers for environmental prediction reanalysis data and a linear stationary wave model the transient vorticity and thermal forcings are explicitly calculated and the diabatic heating is derived as a residual in the thermodynamic energy equation using the april june amj data for 1988 and june august jja data for 1993 the linear stationary wave model is able to reproduce the main features of the geopotential height anomaly for the two seasons when all forcings are included this provides a basis for further investigation of stationary wave response to different forcing mechanisms using the linear model within the linear model framework the linear model responses to different forcings are examined separately the results indicate that the 1988 anomaly over the united states is a result of both the diabatic heating and the transient vorticity and thermal forcings the large anticyclonic anomalies over the north pacific and canada are forced mainly by the diabatic heating the 1993 anomaly however is dominated by the response to transient vorticity forcing by further separating the linear model responses to regional diabatic heating anomalies in 1988 the results indicate that the western north pacific heating is entirely responsible for the anticyclonic center over the north pacific which causes the northward shift and intensification of the pacific jet stream the eastern north pacific heating cooling couplet is the most important for maintaining the north american circulation

rossby wave propagation and the rapid development of upper level anomalous anticyclones during the 1988 u s drought abstract the upper tropospheric circulation is investigated for the three months of april may and june 1988 during which the great plains region of the united states experienced one of its most severe droughts in history it is found that during this period the april june amj seasonal mean anomaly was not representative of the variability of 10 day low pass anomalies rather over north america large fluctuations on monthly and shorter timescales occurred with the dominant streamfunction anomalies not strongly anticyclonic until june in fact the amj anomaly was dominated by two episodes of rapidly developing intense anomalous anticyclones in early and late june examination of the daily 10 day low pass streamfunction anomalies at 300 mb suggests that propagating rossby waves originating in the west pacific played a dominant role in the initiation of these intense anomalous anticyclones numerical experiments with a linear time dependent barotropic model also support this hypothesis these result

taphonomy of debris flow hosted dinosaur bonebeds at dalton wells utah lower cretaceous cedar mountain formation usa abstract a taphonomic study of the lower cretaceous dalton wells dw dinosaur bonebeds near moab utah provides insight into the origins preservational biases and paleobiological significance of one of the richest and most diverse early cretaceous dinosaur sites known the bonebeds occur in a stacked succession of debris flows at the base of the yellow cat member of the cedar mountain formation which was deposited in a seasonally dry alluvial lacustrine setting although only 5 of the locality has been collected more than 4200 bones were recovered representing an assemblage overwhelmingly dominated by dinosaurs with a minimum of 67 individuals that represent at least eight genera the assemblage also includes eight elements from four non dinosaurian reptiles the dinosaur fauna is sauropod dominated mni minimum number of individuals 41 a basal macronarian mni 15 venenosaurus mni 3 a camarasaurid mni 2 and a large number mni 21 of generically unassigned sauropod elements other dinosaurs include the theropods utahraptor mni 9 nedcolbertia mni 2 a possible ornithomimid mni 2 plus a large iguanodontid mni 4 and the ankylosaurid gastonia mni 9 patterns of skeletal articulation and clustering ontogenetic representation and bone surface modification indicate that the assemblage accumulated and was exposed for more than a year as the result one or more multiple mass mortality events likely droughts that culled large numbers of subadults from the biocoenose carcasses and disarticulated elements were reworked then later transported a short distance and buried by a succession of debris flows skeletal representation data patterns of sorting breakage burrows abrasion and scratch marks provide evidence for sorting trampling and scavenging prior to debris flow reworking pre debris flow sorting is attributed to earlier hydraulic winnowing of easily transported elements the intensity and thoroughness of breakage involving 97 of the elements suggest highly focused high load impacts compatible with trampling by sauropods and iguanodontids lightly abraded and vertically displaced elements indicate episodes of trampling in soft mud trampling occurred before and after debris flow transport theropod tooth marks are uncommon but bone scavenging by osteophagous insects was common and severe resulting in substantial damage to articular surfaces comparisons of dw and other debris flow hosted bonebeds indicate that there are few consistent patterns among fossil assemblage and bone modification data however there are numerous similarities in the geological and spatial taphonomy datasets from these sites resulting from the similar physico hydraulic conditions under which elements were transported reworked and buried geologically and taphonomically dalton wells is similar to the blagoveshchensk monodominant hadrosaur bonebed in the udurchukan formation of eastern russia which also is interpreted as a debris flow hyperconcentrated flow deposit dalton wells also shares geologic and taphonomic characteristics with four bonebeds southeast of the town of green river utah and all occur at the base of the yellow cat member the uniform stratigraphic occurrences of the dalton wells blagoveshchensk and the green river sites resting on an unconformity and their shared sedimentologic and taphonomic features indicate that these sites originated in response to similar tectonic depositional and biostratinomic factors

introduction to the special issue commemorating the 30th anniversary of the royal tyrrell museum of palaeontology with a summary of the museum s early history and its research contributions located just west of drumheller in southern alberta canada the royal tyrrell museum of palaeontology rtmp is nestled among outcrops of the upper cretaceous horseshoe canyon formation exposed along the red deer river valley fig 1 since it officially opened on 25 september 19851 the museum has become one of alberta s must see tourist attractions a significant contributor to the local economy and earned an international reputation for the quality of its palaeontological collections and the research conducted by its scientists the rtmp is unique within canada in being the only government supported museum dedicated to palaeontology and it is one of the few such institutions in the world fig 1 the royal tyrrell museum of palaeontology a front of museum and main entrance circa 2010 looking westwards and with horizontal beds of the upper cretaceous horseshoe canyon formation exposed in the walls of the red deer river valley in the distance b aerial photograph oblique angle and looking to the north northeast the museum sits on top of the number 7 coal seam sensu gibson 1977 and at the base of the horsethief member of the horseshoe canyon formation d a eberth pers comm 2015 that stratigraphic position correlates with an age of about 71 5 ma i e late campanian and lies within the upper part of the edmontosaurus regalis pachyrhinosaurus canadensis dinosaur assemblage zone see eberth et al 2013 fig 6 c the iconic running theropod logo that until recently graced the exterior of the museum below a life sized tyrannosaurid sculpture by brian cooley one of many such sculptures by cooley that have been featured at the museum since its opening in 1985 and with the education wing opened in 2003 as the atco tyrrell learning centre in the background d the cretaceous alberta life sized diorama opened in 2007 an example of a rtmp exhibit that relies heavily on discoveries and interpretations by museum researchers in this case work done in the albertosaurus bonebed and at other localities throughout the horseshoe canyon formation all photographs courtesy of the royal tyrrell museum of palaeontology this special issue of the canadian journal of earth sciences presents a collection of papers commemorating the rtmp s 30th or pearl anniversary our rationale for doing a 30th anniversary volume was two fold first it is an opportunity to showcase the breadth of research conducted by current and former museum scientists as well as by some colleagues having a history of collaboration with the rtmp the 13 invited papers included in this volume are a mix of review and original research papers all thematically focused on the geology and palaeontology of alberta to varying degrees each contribution is the result of work supported by the rtmp and relies on specimens housed in the museum s collections second the 30th anniversary is an opportunity to reflect on the rtmp s history and its research program as is typical for most institutions the rtmp has done little to formally document its own history this year likely will be the last major milestone for which the original generation of museum staff are still working and available to share their recollections about the museum fieldwork and research already deaths and departures have winnowed away part of the original

dynamics of the stationary anomalies associated with the interannual variability of the midwinter pacific storm track the roles of tropical heating and remote eddy forcing abstract the leading mode of interannual variability of the midwinter pacific storm track is such that the storm track is weaker during the winters when the pacific jet is strong and stronger when the jet is weak in this paper experiments are conducted using a stationary wave model as well as an idealized global circulation model to explore the roles of anomalous tropical heating and eddy fluxes in forcing the observed pacific jet anomalies it is found that enhanced tropical heating over the region 60 e to the date line 25 s to 25 n acts to force a stronger and narrower pacific jet on average tropical heating may account for about one third of the strong jet anomaly but there is significant year to year variability moreover tropical heating does not appear to contribute to the weak jet anomaly much of the pacific jet anomalies are forced by anomalous eddy fluxes by examining the regional contributions from the pacific the atlantic and asia it is found that local eddy feedback over the paci

nanometre size diamonds in the cretaceous tertiary boundary clay of alberta starting with the discovery of an iridium anomaly at the cretaceous tertiary boundary in italy1 the idea that a large asteroid or comet struck the earth at the end of the cretaceous period has gained wide acceptance2 4 although some workers suggest that massive volcanic eruptions can also explain the observations5 the abundance of small diamonds 3 5 nm in size in chondritic meteorites6 7 prompted us to search for such diamonds in the cretaceous tertiary boundary clay of the red deer valley of alberta the knudsen s farm locality dissolution and oxidation of this clay yielded 45 ng g 1 of a white fraction consisting of more than 97 carbon which was absent from rocks above and below the boundary layer we present evidence that this material is indeed diamond which strengthens further the case for an extraterrestrial impact the diamond indium ratio in the boundary clay may constrain the type of impactor our estimate 1 22 1 is close to the value found in type c2 chondritic meteorites2

protoceratopsian embryos from inner mongolia people s republic of china new protoceratopsid fossils from bayan mandahu include the smallest specimens of protoceratops and bagaceratops recovered to date none of these specimens were found associated with dinosaur eggshe

role of transients in the dynamics of east asian summer seasonal mean circulation anomalies a study of 1993 and 1994 abstract by using the national centers for environmental prediction reanalysis data and a nonlinear barotropic model the transient activities and the possible role of transient vorticity fluxes in the maintenance of east asian summer seasonal mean circulation anomalies associated with japan s extremely cool and wet summer of 1993 and hot and dry summer of 1994 are examined data analysis shows that the summertime atmospheric circulation and the transient activity anomalies exhibit nearly opposite patterns over east asia during these two years vorticity budget calculations indicate that the anomalies of transient activities in these two years produced strong transient vorticity flux forcing anomalies that are comparable in magnitude to the divergent forcing anomalies over east asia the nonlinear barotropic model when forced by the anomalous divergence and transient vorticity flux forcing together produces simulations that bear resemblance to the observed summertime seasonal mean circulation anomalies

fishes from the lower triassic portion of the sulphur mountain formation in alberta canada geological context and taxonomic composition the sulphur mountain formation in alberta canada comprises shales siltstones and limestones laid down on the continental shelf and shoreline along the western margin of the north american craton during the early and middle triassic at least 13 taxa of fossil marine fishes have been found at a number of triassic localities along the front ranges and foothills in alberta common taxa boreosomus birgeria bobasatrania australosomus saurichthys parasemionotids and coelacanths found at localities in alberta are similar to those found at the classic lower and middle triassic localities near wapiti lake british columbia and in east greenland spitzbergen madagascar and china the occurrence of lower triassic fishes in western alberta shows that this fauna was widespread occurring over at least 1000 km of shoreline and that ecological and environmental factors were similar along the western edge of the panthalassic ocean during the early triassic

a review of leidyosuchus canadensis lambe 1907 archosauria crocodylia and an assessment of cranial variation based upon new material cranial morphology of leidyosuchus canadensis lambe 1907 is reviewed based on previously undescribed material seven skulls and eight mandibles this species can be distinctively diagnosed by more than 10 derived features new information supports the contention that l canadensis is the sole representative of leidyosuchus and indicates that it is very different from the other species previously assigned to this taxon the membership of l canadensis within alligatoroidea is also demonstrated by new information revealed in this study ontogenetic and individual variation in the cranial anatomy of l canadensis are documented the contact of the premaxillary maxillary suture with the incisive foramen is not diagnostic of the taxon rather it exhibits individual variation leidyosuchus is endemic to north america there was no faunal interchange of crocodyliforms between north america and central asia during the last two stages of the late cretaceous

allometric growth in tyrannosaurids dinosauria theropoda from the upper cretaceous of north america and asia many tyrannosaurid skeletons have been collected in canada the united states and mongolia these fossils tend to represent mature individuals but juveniles are also known skeletons of five gene