structural and mechanical controls on intrusion related deposits of the tombstone gold belt yukon canada with comparisons to other vein hosted ore deposit types abstract intrusion related gold deposits at the clear creek scheelite dome and dublin gulch properties of the tombstone gold belt tgb yukon territory have dominantly e striking steeply dipping auriferous quartz extension veins within intrusions in adjacent metasedimentary rocks gold is hosted in subvertical nw to nnw striking sinistral faults as veins and breccias in e striking extension veins and locally in e to ene striking fault veins these structural relationships indicate low magnitude broadly e w directed shortening and n s extension during stock emplacement and gold mineralisation at 92 ma the lack of any deviation or deflection of the extension vein orientations in the country rocks with respect to their orientation within the stocks indicates consistent stress trajectories in both rock types these tgb deposits formed at 5 8 km depth where mean and differential stresses may be greater in magnitude than in shallower porphyry environments many porphyry systems feature magmatic related stresses that dominated the local stress field with more variable vein orientations the result conversely orogenic gold systems usually exhibit strong dimensionality in vein orientations fault hosted mineralisation in metasedimentary rocks of the tgb deposits in this study is comparable in geometry but generally smaller in size than in many orogenic gold systems intrusion related systems of the tgb exhibit intermediate structural styles of mineralisation that provide a useful bridge in understanding the diversity of mechanically controlled structural styles in otherwise mostly unrelated gold deposit types

the kosice meteorite fall recovery and strewn field we provide the circumstances and details of the fireball observation search expeditions recovery strewn field and physical characteristics of the kosice meteorite that fell in slovakia on february 28 2010 the meteorite was only the 15th case of an observed bolide with a recovered mass and subsequent orbit determination despite multiple eyewitness reports of the bolide only three videos from security cameras in hungary were used for the strewn field determination and orbit computation multiple expeditions of professionals and individual searchers found 218 fragments with total weight of 11 3 kg the strewn field with the size of 593 km is characterized with respect to the space distribution of the fragments their mass and size frequency distribution this work describes a catalog of 78 fragments mass size volume fusion crust names of discoverers geographic location and time of discovery which represents the most complex study of a fresh meteorite fall from the analytical results we classified the kosice meteorite as an ordinary h5 chondrite

tidal distortions and flood dominance at five small tidal inlets in southern maine maximum and mean flood current velocities exceeded ebb current velocities by an average of more than 20 cm s 1 at five small inlets along the southern coast of maine distortion of the tidal wave as it interacts with these shallow inlets such that the rising tide duration averages 3 22 h less than the falling tide duration may be the cause of flood current dominance at these inlets tide records from three locations at ogunquit inlet located along the southern coast of maine show that the 29 day average tide duration asymmetry increases from a rising tide that is 0 07 h longer than the falling tide for the offshore record to a rising tide that is 2 15 and 5 15 h shorter than the falling tide for the inlet throat and bay records respectively previous field studies and numerical models of tidal asymmetry have not examined tidal distortion in very shallow inlets where the channels shoal to depths shallower than the forcing tide amplitude at the inlets investigated in this paper channels are shallower than the ocean tide amplitude by an average of 30 cm a model is presented that explains how the shallow inlet bathymetry truncates the ocean tide and produces an inlet tide characterized by an extended falling tide and a shortened rising tide duration the dominance of flood tidal currents at these inlets produces net landward sediment transport

post lgm upward shift of the mediterranean outflow water recorded in a contourite drift off nw spain abstract the nw iberian continental margin is characterised by a complex morphology and by a sedimentary system which was highly dynamic over glacial to interglacial times the sedimentary history of the continental slope was strongly influenced by the interaction of bottom currents with topographic highs of structural origin leading to the accumulation of several sediment drifts a combined analysis of gravity cores from different water depth with hydroacoustic data reveals the vertical behaviour of the upper mediterranean outflow water mow core after the last glacial maximum lgm a coarser grained interval during deglacial and early holocene times 17 2 to 9 9 cal ka bp points to an increase in bottom current strength this increase in velocity was probably related to oceanic density fronts which migrated through the 300 m thick transition zone between the underlying labrador sea water and the overlying mow radiocarbon dates timed the current strengthening to 17 2 cal ka bp and a following weakening of the bottom current to 13 3 cal ka bp at 1965 m water depth and to 9 9 cal ka bp at 1885 m water depth the depth dependent current weakening suggests an upward shifting of the transition zone by 80 m that was related either to an overall shallowing of mow or a vertical contraction of this water mass the upward movement happened over a time interval of approximately 3 4 thousand years in addition sediment core analysis reveals significant lateral heterogeneities within cm to dm thick sediment layers in the contourite drift these heterogeneities suggest a need of a detailed core coverage across current influenced deposits for palaeoceanographic studies to minimize misinterpretations

atmospheric energy deposition modeling and inference for varied meteoroid structures abstract asteroids populations are highly diverse ranging from coherent monoliths to loosely bound rubble piles with a broad range of material and compositional properties these different structures and properties could significantly affect how an asteroid breaks up and deposits energy in the atmosphere and how much ground damage may occur from resulting blast waves we have previously developed a fragment cloud model fcm for assessing the atmospheric breakup and energy deposition of asteroids striking earth the approach represents ranges of breakup characteristics by combining progressive fragmentation with releases of variable fractions of debris and larger discrete fragments in this work we have extended the fcm to also represent asteroids with varied initial structures such as rubble piles or fractured bodies we have used the extended fcm to model the chelyabinsk benesov kosice and tagish lake meteors and have obtained excellent matches to energy deposition profiles derived from their light curves these matches provide validation for the fcm approach help guide further model refinements and enable inferences about pre entry structure and breakup behavior results highlight differences in the amount of small debris vs discrete fragments in matching the various flare characteristics of each meteor the chelyabinsk flares were best represented using relatively high debris fractions while kosice and benesov cases were more notably driven by their discrete fragmentation characteristics perhaps indicating more cohesive initial structures tagish lake exhibited a combination of these characteristics with lower debris fragmentation at high altitudes followed by sudden disintegration into small debris in the lower flares results from all cases also suggest that lower ablation coefficients and debris spread rates may be more appropriate for the way in which debris clouds are represented in fcm offering an avenue for future model refinement

regional scale landslide susceptibility mapping using the weights of evidence method an example applied to linear infrastructure large landslides are common in the gently sloping clay plains of the saint lawrence lowlands of eastern canada these tend to occur along rivers carved into the marine soils deposited in the former champlain sea which occupied the area roughly 10 000 years ago this paper presents a landslide susceptibility model developed at the regional scale using a bivariate statistical method the weights of evidence method the analysis considers the association of existing large landslides in a portion of the study area with key terrain features such as ground elevation flow accumulation in adjacent streams soil type soil thickness and land use the resulting model identifies three different levels of susceptibility low low to moderate and moderate to high these descriptors are related statistically to the probability of encountering existing large landslides within 500 m 1 or 2 km respectively the model is tested along primary railway corridors and isolates 8 of the total length for further consider

gis based weights of evidence modelling of rainfall induced landslides in small catchments for landslide susceptibility mapping landslide susceptibility mapping is a vital tool for disaster management and planning development activ ities in mountainous terrains of tropical and subtropical environments in this paper the weights of evidence modelling was applied within a geographical information system gis to derive landslide susceptibility map of two small catchments of shikoku japan the objective of this paper is to evaluate the importance of weights of evidence modelling in the generation of landslide susceptibility maps in relatively small catchments having an area less than 4 sq km for the study area in moriyuki and monnyu catchments northeast shikoku island in west japan a data set was generated at scale 1 5 000 relevant thematic maps representing various factors e g slope aspect relief flow accumulation soil depth soil type land use and distance to road that are related to landslide activity were generated using field data and gis techniques both catchments have homogeneous geology and only consist of cretaceous granitic rock thus bedrock geology was not considered in data layering during gis analysis success rates were also estimated to evaluate the accuracy of landslide suscepti bility maps and the weights of evidence modelling was found useful in landslide susceptibility mapping of small catchments

an evaluation of bagnold s dimensionless conefficient of proportionality using measurements of sandwave movement abstract only a few observations are currently available from the tidal marine environment which can be used to evaluate sediment transport formulae research carried out on sandwave movement indicates that most of the sediment transport is restricted to the crestal area mean rates of sediment transport were calculated from volumetric changes between successive slack waters over a nine day period spanning spring tides the results were used in conjunction with boundary layer flow measurements to calculate the threshold velocity for the movement of sediment and also to evaluate bagnold s 1963 dimensionless coefficient of proportionality k comparisons are made with the flume data of guy et al 1966 for the appropriate sediment grain size the dependence of k upon normalised excess shear stress was found to be weaker than that suggested by sternberg 1972 within the range of flow velocities considered there was no indication that k tended towards a constant at high flow velocities

rumanova h5 chondrite slovaki an h5 chondrite was found near the village of rumanova slovakia dominant minerals of the meteorite are enstatite olivine kamacite taenite and troilite the minor minerals are oligoclase augite pigeonite accessory chromite whitlockite and chlorapatite the composition of olivine fa19 0 and low ca orthopyroxene fs17 0 and the density and chemical composition of the meteorite correspond to those of an h chondrite normal zoning of ni in metal grains and parallel planar fractures in olivine suggest weak shock metamorphism of stage s3 due to moderate oxidation of metal iron hydroxides were formed corresponding to weathering stage w2

a statistical model for presence of late season frozen ground in discontinuous permafrost at dublin gulch yukon this paper describes geostatistical analyses completed at a discontinuous permafrost site in central yukon to develop a predictive model for the presence of late season frozen ground in support of planning and design for potential site develop ment the most important factors in the bivariate statistical model were soil type as determined through terrain analysis and slope aspect as inferred from available topographic data the other three factors included in the final model were profile curvature slope angle and ground elevation each interpreted from available topographic data the resulting model subdivides the site into three broad classes of frozen ground likelihood low where frozen ground can be expected to be encountered in late summer at 15 of observation locations medium where 50 of the ground is expected to remain frozen and high where 85 of the ground is expected to remain frozen new test pit and borehole data from the summer of 2012 were used to verify model performance the inferred correlations between frozen ground and soil type aspect curvature slope and elevation obtained in this case study may provide useful information relative to expected permafrost occurrence at sites in central yukon with similar geology and physiography

stability of bedforms in a tidal environment abstract large scale bedforms developed in a tide dominated salt estuary near sapelo island georgia are morphologically separated into two distinct groups megaripples include bedforms 4 to 15 m in wavelength and 10 to 75 cm in height sand waves are 15 to 45 m in wavelength and 85 to 130 cm in height and can be further subdivided into megarippled forms and smooth crested forms ebb oriented geometry of large scale bedforms is maintained through both ebb and flood portions of the tidal cycle bedforms are in equilibrium with peak tidal flow and ebb orientation is the direct result of large pressure gradients and related bed shear values that develop during the ebb bedform heights can be statistically related to flow power shear velocity water depth and sediment grain size mean flow velocity values used in many previous studies of bedform stability did not produce significant f statistic values in a multiple linear regression procedure used to discern relationships among variables stability fields of bedform types can be empirically defined using parameters statistically significant in the regression analysis flow power shear velocity water depth and sediment grain size were used in various combinations to construct bivariate plots showing separate stability fields of sand waves and megaripples

the relative importance of landward directed tidal sediment transport versus freshwater flood events in the normanby river estuary cape york peninsula australia variation in freshwater discharge into the tropical estuaries of northern australia is extreme between wet and dry seasons and the resultant effect upon sedimentary processes in relation to the geomorphological evolution of the coastal plain is largely undocumented observations of tidal height currents and suspended sediment concentrations were taken over a 3 week period in july 1994 dry season in the mesotidal normanby river estuary northeastern australia the estuary and adjacent inner shelf were surveyed using a 3 5 khz seismic system and an echo sounder and sampled with a total of 175 grab samples and 17 vibrocores sediment sampling occurred in july 1994 december 1994 and march 1996 the latter following the 1995 96 wet season flood tidal currents dominate the estuary at spring tides with peak velocities of 0 85 m s 1 recorded at the mouth measured tidally driven sediment transport is landward at the mid estuary site and extrapolation gives estimates of 15 000 30 000 tonnes of bedload and ca 50 000 tonnes of suspended load moved landward per year the surficial sediments in the main estuarine channel are inferred to be holocene and are 1 delta front sediments which extend to at least 6 km seawards of the mouth 2 lower estuarine silts located at 2 11 km landwards of the mouth and 3 channel dune sands 13 to 50 km i e nearly to the tidal limit all dunes surveyed on the river bed during the dry season showed a strong asymmetry with lee faces consistently facing landward whether surveyed at high or low water indicating landward bedload sediment transport in the dry season an underlying hard regional surface is exposed at 11 13 km landward of the estuary mouth in the absence of direct measurements we have estimated sediment transport during wet season freshwater flood events a major freshwater flood event may transport only 6000 32 000 tonnes of bedload seawards and modern wet season events appear incapable of supplying sand in significant quantities to the inner shelf we infer that for the late holocene the frequency magnitude and duration of wet season events has been insufficient to reverse the landward bedload transport driven by tidal currents in the dry season

estimates of sand transport in the oosterschelde tidal basin using current velocity measurements abstract estimates of sand transport have been made from mid depth velocity measurements in the oosterschelde tidal basin southwestern netherlands this involves 1 the use of a two region composite boundary layer model in deriving the local spatially averaged bed shear stress from velocity distributions over large bedforms megaripples and sandwaves the two regions are divided at 100 cm above the bed with an outer region roughness length of 1 5 cm and an inner region roughness length of 0 15 cm 2 the application of a modified bagnold s transport equation with the transport coefficient k depending on dimensionless excess shear stress in the form of a power law the calculations indicate very active sand movement in the present day oosterschelde tidal basin local sediment circulation may develop around shoals channel floor erosion may occur in parting areas of sediment transport the net sediment transport is mainly in the ebb direction estimates of sediment budget for the last 20 years show that large amounts of sand have been eroded from the oosterschelde tidal basin and transported to the ebb delta area these results are comparable with other estimates from echo sounding data reflecting the rapid adjustment of the basin to the increased tidal prism such active sediment redistribution and major morphological evolution processes would have important influence on the structural organization and sequential development of estuary ebb delta deposits information about the sedimentary processes in present day estuary tidal basins is valuable for a better understanding of ancient examples

an entry model for the tagish lake fireball using seismic satellite and infrasound records we present instrumental observations of the tagish lake fireball and interpret the observed characteristics in the context of two different models of ablation from these models we estimate the pre atmospheric mass of the tagish lake meteoroid to be 56 tonnes and its porosity to be between 37 and 58 with the lowest part of this range most probable these models further suggest that some 1300 kg of gram sized or larger tagish lake material survived ablation to reach the earth s surface representing an ablation loss of 97 for the fireball satellite recordings of the tagish lake fireball indicate that 1 1 1012 j of optical energy were emitted by the fireball during the last 4 s of its flight the fraction of the total kinetic energy converted to light in the satellite pass band is found to be 16 infrasonic observations of the airwave associated with the fireball establish a total energy for the event of 1 66 0 70 kt tnt equivalent energy the fraction of this total energy converted to acoustic signal energy is found to be between 0 10 and 0 23 examination of the seismic recordings of the airwave from tagish lake have established that the acoustic energy near the sub terminal point is converted to seismic body waves in the upper most portion of the earth s crust the acoustic energy to seismic energy coupling efficiency is found to be near 10 6 for the tagish lake fireball the resulting energy estimate is near 1 7 kt corresponding to a meteoroid 4 m in diameter the seismic record indicates extensive nearly continuous fragmentation of the body over the height intervals from 50 to 32 km seismic and infrasound energy estimates are in close agreement with the pre atmospheric mass of 56 tonnes established from the modeling the observed flight characteristics of the tagish lake fireball indicate that the bulk compressive strength of the pre atmospheric tagish lake meteoroid was near 0 25 mpa while the material compressive strength most appropriate to the recovered meteorites was closer to 0 7 mpa these are much lower than values found for fireballs of ordinary chondritic composition the behavior of the tagish lake fireball suggests that it represents the lowest end of the strength spectrum of carbonaceous chondrites or the high end of cometary meteoroids the bulk density and porosity results for the tagish lake meteoroid suggest that the low bulk densities measured for some small primitive bodies in the solar system may reflect physical structure dominated by microporosity rather than macroporosity and rubble pile assemblages

the kosice meteorite fall atmospheric trajectory fragmentation and orbit the kosice meteorite fall occurred in eastern slovakia on february 28 2010 22 25 ut the very bright bolide was imaged by three security video cameras from hungary detailed bolide light curves were obtained through clouds by radiometers on seven cameras of the european fireball network records of sonic waves were found on six seismic and four infrasonic stations an atmospheric dust cloud was observed the next morning before sunrise after careful calibration the video records were used to compute the bolide trajectory and velocity the meteoroid of estimated mass of 3500 kg entered the atmosphere with a velocity of 15 km s 1 on a trajectory with a slope of 60 to the horizontal the largest fragment ceased to be visible at a height of 17 km where it was decelerated to 4 5 km s 1 a maximum brightness of absolute stellar magnitude about 18 was reached at a height of 36 km we developed a detailed model of meteoroid atmospheric fragmentation to fit the observed light curve and deceleration we found that kosice was a weak meteoroid which started to fragment under the dynamic pressure of only 0 1 mpa and fragmented heavily under 1 mpa in total 78 meteorites were recovered in the predicted fall area during official searches other meteorites were found by private collectors known meteorite masses ranged from 0 56 g to 2 37 kg the meteorites were classified as ordinary chondrites of type h5 and shock stage s3 the heliocentric orbit had a relatively large semimajor axis of 2 7 au and aphelion distance of 4 5 0 5 au backward numerical integration of the preimpact orbit indicates possible large variations of the orbital elements in the past due to resonances with jupiter

a note on tidal asymmetry in the severn estuary a one dimensional non linear numerical model is used to investigate the tidally averaged frictional stress and set up of water level due to tidal asymmetry in the severn estuary these quantities depend on the overtides in the region a linearized model of the overtides is applied to calculations of the m4 currents in order to delineate the mechanisms responsible for their generation the relative importance of individual non linear mechanisms to the tidally averaged stress and set up is determined these mechanisms are interactions between tidal flow and changes in depth or breadth over a cross section frictional interaction between the tidal flow and stokes drift interaction between the tidal fluctuations in water depth and frictional retardation and non linear advection

tidal dynamics and substrate response in a salt marsh estuary abstract the tidal wave in the duplin river a well mixed salt marsh estuary on the georgia coast displays distinctive forms of asymmetry in the horizontal and vertical tides ebb current speeds reach a maximum of up to 30 higher than corresponding flood currents and maximum ebb and flood discharges are both displaced toward the time of high water duration of the flooding tide can be more than one hour longer than duration of the corresponding ebbing tide tidal asymmetry is clearly reflected in the tidally varying dynamic balance of the estuary estimated from a simplified equation of motion the ebb related pressure gradient term and corresponding shear stress term at the bed are an order of magnitude greater than flood related pressure gradient and bed shear ebb dominated asymmetry in the duplin river is attributed to interaction of the principal lunar m2 tide with its first harmonic overtide m4 generation of the m4 tide is thought to be from non linearities that arise from continuity of the salt marsh estuary which is best described by a changing basin area model substrate response to ebb dominated tidal dynamics is the development of largescale bedforms that maintain ebb oriented geometry through both ebb and flood tide bedforms are in equilibrium with maximum ebb related bed shear values which result in sand transport rates that are an order of magnitude greater during ebb compared with flood tide

the dynamics of a megaripple field in northern spencer gulf south australia abstract the composition form and migration of megaripples in a megaripple field in a tidal channel of northern spencer gulf south australia were examined over a year migration rates of megaripples ranged from about 2 m yr 1 for sandwaves 3 m high to about 8 m yr 1 for megaripples 0 4 m high migration of the wave form was regular at some sites but irregular at others where differential migration and erosion gave rise to branching or coalescence of megaripples winter migration rates were greater than summer rates at most sites estimates of sediment transport rates at two cross sections of the field suggest only slow and minor net flood transport of sediment of 40 70 m 3 yr 1 sediments are predominantly medium grained sand well sorted at the megaripple crests and elsewhere on fast moving megaripples and poorly sorted in troughs between megaripples the predominantly negative skewness values of the sediments support the conclusion that tidal currents selectively rework the sediments with little input of new material

a comprehensive study of distribution laws for the fragments of kosice meteorite in this study we conduct a detailed analysis of the kosice meteorite fall february 28 2010 to derive a reliable law describing the mass distribution among the recovered fragments in total 218 fragments of the kosice meteorite with a total mass of 11 285 kg were analyzed bimodal weibull bimodal grady and bimodal lognormal distributions are found to be the most appropriate for describing the kosice fragmentation process based on the assumption of bimodal lognormal bimodal grady bimodal sequential and bimodal weibull fragmentation distributions we suggest that prior to further extensive fragmentation in the lower atmosphere the kosice meteoroid was initially represented by two independent pieces with cumulative residual masses of approximately 2 and 9 kg respectively the smaller piece produced about 2 kg of multiple lightweight meteorite fragments with the mean around 12 g the larger one resulted in 9 kg of meteorite fragments recovered on the ground including the two heaviest pieces of 2 374 kg and 2 167 kg with the mean around 140 g based on our investigations we conclude that two to three larger fragments of 500 1000 g each should exist but were either not recovered or not reported by illegal meteorite hunters

sediment transport and trapping in marsh systems implications of tidal flux studies although the concept that marshes act as major sediment sinks may be accurate when viewing them over the last few millennia tidal transport studies suggest considerable variability with most marshes presently exporting material on an annual basis high salinity marshes along the mid atlantic coast of the united states appear to be losing 1 2 kg m 2 yr 1 while submerged upland marshes on the delmarva peninsula are eroding at rates of up to 14 kg m 2 yr 1 by comparison at least one deltaic marsh on the dutch coast along with several estuarine marshes appear to be accumulating sediment in order to assess the trapping ability of marshes in large estuaries we constructed a sediment budget for chesapeake bay which included a variety of wetland types calculations indicate that estuarine marshes trap 5 11 of the annual chesapeake bay sediment input or about one half that previously estimated it appears that most sedimentation in estuaries and perhaps other coastal systems occurs in subtidal flats below the limit of emergent marsh vegetation as mud flats become vegetated and estuarine infilling proceeds there may be a tendency for tidal currents to become ebb dominated which promotes a net export of particulates the extent to which major storm events are capable of returning enough material to balance the long term accretionary budget of tidal marshes and keep them abreast of rising sea level is open to question differences in tidal dynamics seasonal changes in sea levels and higher temperatures may help explain why in the u s southern marshes are more susceptible to export and eventual erosion than northern marshes we hypothesize that another factor the recent reductions of terrigenous sediment inputs from the southern river systems of the u s may also be critical sediment starvation may have led to undernourishment of wetland systems of the coastal zone over the last half century which may be reflected in the net export measured in the tidal marshes in this region furthermore we postulate that changes in sediment inputs are more important than eustatic sea level rise in causing the past losses of marshes which are now undergoing mass erosion thus future wetland survival will depend as much as particulate inputs to the coastal zone as on the prospects of a global rise in sea level and more efforts should be made to quantify the sediment budgets of tidal marshes

on bagnold s sediment transport equation in tidal marine environments and the practical definition of bedload bagnold s sediment transport equation has proved to be important in studying tidal marine environments this paper discusses three problems concerning bagnold s transport equation and its practical application 1bagnold s suspended load transport equation and the total load transport equation with are incorrect from the viewpoint of energy conservation in these equations the energy loss due to bedload transport has been counted twice the correct form should be for suspended load transport and for total load transport with 2the commonly used bagnold s transport coefficient k varies as a non linear function of the dimensionless excess shear stress which can be represented best by the power law where the coefficient a and exponent b depend on sediment grain size d the empirical values of a and b for fine to medium grained sands are determined using guy et al s 1966 flume experiment data 3the sediment transport rates predicted from this equation are compared with bedform migration measurements in the flume and the field this comparison shows that the sediment transport rates measured from bedform migrations are higher than the predicted bedload transport rates but comparable to the calculated total load bedload plus intermittent suspended load transport rates this indicates that bedform migration involves both bedload and intermittent suspended load transport as a logical conclusion bedform migration data should be compared with bagnold s total load transport equation rather than with his bedload transport equation in this respect the term bed material might be more appropriate than the term bedload for estimating sediment transport rate from bedform migration data the sediment transport rates predicted from this modified bagnold transport equation are in good agreement with field measurements of bedform migration rates in four individual tidal marine environments which cover a wide range of sediment grain size flow velocity and bedform conditions ranging from small ripples megaripples to sandwaves

climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones northern canada1 21this article is one of a series of papers published in this cjes special issue on the theme of fundamental and applied research on permafrost in canada 2earth science sector ess contribution 20110128 climate ground temperature relations are examined under a range of conditions for 10 sites across northern canada the sites are located between 60 n and 83 n and at elevations of 40 to 1840 m ab

mountain permafrost probability mapping using the bts method in two climatically dissimilar locations northwest canada the basal temperature of snow bts method was used to predict permafrost distribution in two climatologically dissimilar mountain environments in northwest canada permafrost probability maps with 30 m 30 m grid cells were generated for part of the ruby range yukon territory 425 km2 and for the haines summit area northern british columbia 536 km2 using winter bts measurements in conjunction with late summer ground truthing by probing and digging pits to physically verify the presence of permafrost bts values and hence permafrost distribution were modeled using elevation and potential incoming solar radiation pisr for the ruby range pisr was not significant at haines summit probably because persistent cloudiness associated with its more maritime climatic regime reduced aspect induced variability in insolation probability maps indicate that 66 of the ruby range area and 43 of the haines summit area are underlain by permafrost therefore the ruby range should be classified as extensiv

mineralogy petrography geochemistry and classification of the kosice meteorite the kosice meteorite was observed to fall on 28 february 2010 at 23 25 ut near the city of kosice in eastern slovakia and its mineralogy petrology and geochemistry are described the characteristic features of the meteorite fragments are fan like mosaic lamellar and granular chondrules which were up to 1 2 mm in diameter the fusion crust has a black gray color with a thickness up to 0 6 mm the matrix of the meteorite is formed mainly by forsterite fo80 6 diopside enstatite fs16 7 albite troilite fe ni metals such as iron and taenite and some augite chlorapatite merrillite chromite and tetrataenite plagioclase like glass was also identified relative uniform chemical composition of basic silicates partially brecciated textures as well as skeletal taenite crystals into troilite veinlets suggest monomict breccia formed at conditions of rapid cooling the kosice meteorite is classified as ordinary chondrite of the h5 type which has been slightly weathered and only short veinlets of fe hydroxides are present the textural relationships indicate an s3 degree of shock metamorphism and w0 weathering grade some fragments of the meteorite kosice are formed by monomict breccia of the petrological type h5 on the basis of ree content we suggest the kosice chondrite is probably from the same parent body as h5 chondrite moravka from czech republic electron microprobe analysis empa with focused and defocused electron beam whole rock analysis wra inductively coupled plasma mass and optical emission spectroscopy icp ms icp oes and calibration free laser induced breakdown spectroscopy cf libs were used to characterize the kosice fragments the results provide further evidence that whole rock analysis gives the most accurate analyses but this method is completely destructive two other proposed methods are partially destructive empa or nondestructive cf libs but only major and minor elements can be evaluated due to the significantly lower sample consumption

observations and analysis of giant sand wave fields on the taiwan banks northern south china sea abstract understanding sand wave dynamics is of importance in marine science and also has relevance in engineering giant sand wave fields wave heights up to 10 m are not common and thus have been relatively rarely studied this paper presents the first study on bedform changes related to giant sand wave geomorphology on the taiwan banks using data from three repeated multi beam bathymetric surveys 2011 2012 and 2013 and a spatial cross correlation method different sand transport patterns are obtained classical crest perpendicular migration is observed in the small sand waves with migration rates of 1 5 m a and migration is parallel with the current direction however the giant sand waves are immobile over the observed periods and along crest transport sand transport has been observed that is perpendicular to the predominant current direction statistical results support these findings and thus illustrate a type of sediment transport pattern that differs from other sand wave fields around the world it is concluded that the giant sand waves act as a bathymetric obstacle thus changing the direction of bottom currents flowing over them resulting in a change in sediment transport pattern on the taiwan banks

comparisons of measured and predicted sediment transport rates in tidal currents abstract this paper describes bedload transport measurements in a large scale sedimentary system on the british continental shelf steady flow sediment transport theories are applied to oscillatory tidal currents and various equations are compared with measured transport rates from tracer dispersion experiments the effects of waves on both measured and predicted rates are briefly considered and the predicted directions of sediment movement compared with those inferred from sedimentological data