charge transfer and in cloud structure of large charge moment positive lightning strokes in a mesoscale convective system 1 lightning observations in the very high frequency band and measurements of ultra low frequency magnetic fields are analyzed to investigate the charge transfer and in cloud structure of eight positive cloud to ground cg strokes in a mesoscale convective system although no high altitude images were recorded these strokes contained large charge moment changes 1500 3200 c km capable of producing nighttime sprites even though the convective region of the storm was where the flashes originated and where the cg strokes could occur the charge transferred to ground was mainly from the stratiform region the post stroke long continuing currents were connected to highly branched negative leader extension into the stratiform region while the storm dissipated the altitude of negative leader propagation in the stratiform area dropped gradually from 8 to 5 km indicating that in some and perhaps all of these strokes it was the upper positive charge in the stratiform region that was transferred

permafrost and climate in europe monitoring and modelling thermal geomorphological and geotechnical responses we present a review of the changing state of european permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of svalbard and the discontinuous high altitude mountain permafrost of iceland fennoscandia and the alps the paper focuses on methodological developments and data collection over the last decade or so including research associated with the continent scale network of instrumented permafrost boreholes established between 1998 and 2001 under the european union pace project data indicate recent warming trends with greatest warming at higher latitudes equally important are the impacts of shorter term extreme climatic events most immediately reflected in changes in active layer thickness a large number of complex variables including altitude topography insolation and snow distribution determine permafrost temperatures the development of regionally calibrated empirical statistical models and physically based process oriented models is described and it is shown that though more complex and data dependent process oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed we report on recent research into ground ice formation including ice segregation within bedrock and vein ice formation within ice wedge systems the potential impacts of climate change on rock weathering permafrost creep landslides rock falls debris flows and slow mass movements are also discussed recent engineering responses to the potentially damaging effects of climate warming are outlined and risk assessment strategies to minimise geological hazards are described we conclude that forecasting changes in hazard occurrence magnitude and frequency is likely to depend on process based modelling demanding improved understanding of geomorphological process response systems and their impacts on human activity

transionospheric attenuation of 100 khz radio waves inferred from satellite and ground based observations 1 around fifty loran long range navigation transmitters in the northern hemisphere currently launch continuously pulsed 100 khz radio waves into the earth s atmosphere for marine navigation it is discovered that the 100 khz radio waves from the loran transmissions can be detected by the demeter satellite at an altitude of 660 km above the transmitters these novel electric field measurements in space enable the determination of the nocturnal transionospheric attenuation by comparison with ground based electric field measurements the electric field measurements on the satellite indicate that the nocturnal transionospheric attenuation of 100 khz radio waves from loran transmissions is equivalent to a nocturnal subionospheric attenuation of the 100 khz radio waves at a distance of 7 9 mm the radio waves exhibit an average subionospheric attenuation of 5 db mm and it is concluded that the nocturnal transionospheric attenuation of 100 khz radio waves is 35 45 db this result enables future space missions to quantify the intensity of lightning discharges associated with transient luminous events and terrestrial ray flashes

lightning induced brightening in the airglow layer this report describes a transient luminosity observed at the altitude of the airglow layer about 95 km in coincidence with a lightning flash in a tropical oceanic thunderstorm directly beneath it this event provides new evidence of direct coupling between lightning and ionospheric events this luminous event in the ionosphere was the only one of its kind observed during an examination of several thousand images of lightning recorded under suitable viewing conditions with space shuttle cameras several possible mechanisms and interpretations are discussed briefly

ice age at the middle late jurassic transition a detailed record of sea surface temperatures in the northern hemisphere based on migration of marine invertebrate fauna ammonites and isotopic thermometry 18o values of shark tooth enamel indicates a severe cooling at the middle late jurassic transition mljt about 160 ma ago the magnitude of refrigeration 1 3 c for lower middle latitudes and its coincidence in time with an abrupt global scale fall of sea level documented through sequence stratigraphy are both suggestive of continental ice formation at this time ice sheets may have developed over the high latitude mountainous regions of far east russia the drastic cooling just post dated the middle late callovian widespread deposition of organic rich marine sediments e g northwestern europe central atlantic and arabian peninsula this thermal deterioration can thus be ascribed to a downdraw in atmospheric co2 via enhanced organic carbon burial which acted as a negative feedback effect i e the inverse greenhouse effect the glacial episode of the mljt climaxed in the late callovian lasted about 2 6 myr and had a pronounced asymmetrical pattern composed of an abrupt 0 8 myr temperature fall opposed to a long term 1 8 myr stepwise recovery the glacial conditions at the mljt reveal that atmospheric co2 levels could have dropped temporarily to values lower than 500 ppmv during mesozoic times

array analysis of electromagnetic radiation from radio transmitters for submarine communication the array analyses used for seismic and infrasound research are adapted and applied here to the electromagnetic radiation from radio transmitters for submarine communication it is found that the array analysis enables a determination of the slowness and the arrival azimuth of the wave number vectors associated with the electromagnetic radiation the array analysis is applied to measurements of 20 24 khz radio waves from transmitters for submarine communication with an array of 10 radio receivers distributed over an area of 1 km 1 km the observed slowness of the observed wave number vectors range from 2 7 ns m to 4 1 ns m and the deviations between the expected arrival azimuths and the observed arrival azimuths range from 9 7 to 14 5 the experimental results suggest that it is possible to determine the locations of radio sources from transient luminous events above thunderclouds with an array of radio receivers toward detailed investigations of the electromagnetic radiation from sprites

syn depositional alteration of coral reef framework through bioerosion encrustation and cementation taphonomic signatures of reef accretion and reef depositional events the development of coral reef framework and the preservational character of both in situ and rubble coral is strongly influenced by a range of physical chemical and biologically mediated taphonomic processes these operate at or just below the reef framework water interface and can be defined as having either a constructive or destructive effect upon primary reef framework i e coral constituents constructional activities add additional calcium carbonate to the primary framework structure via secondary framework growth and early cementation destructive processes which remove or degrade primary and secondary framework carbonate are associated with the effects of either physical mainly storm disturbance or biological erosion termed bioerosion key bioeroding groups include the grazing fish and echinoid groups as well as the activities of an array of infaunal borers these include specific groups of sponges bivalves and worms termed macroborers as well as cyanobacteria chlorophytes rhodophytes and fungi termed microborers the relative importance of each process and the rates at which they operate vary spatially across individual reef systems in addition many of these processes leave distinctive signatures on or in the coral framework in some cases e g calcareous encrusters these are the skeletons of the organisms themselves whilst in other cases the organism may leave behind a trace of their activity e g macro and microborers these represent useful palaeoenvironmental tools firstly because they often have good preservation potential and secondly because the range and extent of many of the individual species groups and processes involved exhibit reasonably well constrained environment and or depth related distributions as a result these taphonomically important organisms or processes can be used to delineate between reef environments in core or outcrop and to aid the interpretation of reef depositional processes and events this review summarises current understanding regarding the distribution of these species processes within contemporary reef settings and considers the suites of taphonomic signatures that may aid in the recognition and interpretation of depositional environments and events

succession in a jurassic marine cavity community and the evolution of cryptic marine faunas a cavity dwelling fauna from the middle jurassic of the western interior shows a succession controlled by increasing restriction of the cavities most likely by sediment infilling the succession proceeds from large and ubiquitous bivalves to smaller serpulids cyclostome bryozoans and thecideidine brachiopods there is a concurrent decrease in biomass and percent cover this jurassic fauna demonstrates that marine cavity dwelling faunas were specifically adapted to their environments at least 160 m y ago

properties of natural supraglacial debris in relation to modelling sub debris ice ablation as debris covered glaciers become a more prominent feature of a shrinking mountain cryosphere there is increasing need to successfully model the surface energy and mass balance of debris covered glaciers yet measurements of the processes operating in natural supraglacial debris covers are sparse we report measurements of vertical temperature profiles in debris on the ngozumpa glacier in nepal that show i conductive processes dominate during the ablation season in matrix supported diamict ii ventilation may be possible in coarse surface layers iii phase changes associated with seasonal change have a marked effect on the effective thermal diffusivity of the debris effective thermal conductivity determined from vertical temperature profiles in the debris is generally 30 higher in summer than in winter but values depend on the volume and phase of water in the debris surface albedo can vary widely over small spatial scales as does the debris thickness measurements indicate that debris thickness is best represented as a probability density function with the peak debris thickness increasing down glacier the findings from ngozumpa glacier indicate that the probability distribution of debris thickness changes from positively skewed in the upper glacier towards a more normal distribution nearer the terminus although many of these effects remain to be quantified our observations highlight aspects of spatial and temporal variability in supraglacial debris that may require consideration in annual or multi annual distributed modelling of debris covered glacier surface energy and mass balance copyright 2012 john wiley sons ltd

coordinated observations of sprites and in cloud lightning flash structure 1 the temporal and spatial development of sprite producing lightning flashes is examined with coordinated observations over an asymmetric mesoscale convective system mcs on 29 june 2011 near the oklahoma lightning mapping array lma sprites produced by a total of 26 lightning flashes were observed simultaneously on video from bennett colorado and hawley texas enabling a triangulation of sprites in comparison with temporal development of parent lightning in particular negatively charged stepped leaders in three dimensional space in general prompt sprites produced within 20 ms after the causative stroke are less horizontally displaced typically 30 km however both prompt and delayed sprites are usually centered within 30 km of the geometric center of relevant lma sources with affinity to negative stepped leaders during the prior 100 ms interval multiple sprites appearing as dancing jumping events associated with a single lightning flash could be produced either by distinct strokes of the flash by a single stroke through a series of current surges superposed on an intense continuing current or by both our observations imply that sprites elongated in one direction are sometimes linked to in cloud leader structure with the same elongation and sprites that were more symmetric were produced above the progression of multiple negative leaders this suggests that the large scale structure of sprites could be affected by the in cloud geometry of positive charge removal based on an expanded dataset of 39 sprite parent flashes by including more sprites recorded by one single camera over the same mcs the altitude above mean sea level msl of positively charged cloud region tapped by sprite producing strokes declined gradually from 10 km msl 35 c to around 6 km msl 10 c as the mcs evolved through the mature stage on average the positive charge removal by causative strokes of sprites observed on 29 june is centered at 3 6 km above the freezing level or at 7 9 km above ground level

a study of the possibility of sprites in the atmospheres of other planets 1 sprites are a spectacular type of transient luminous events which occur above thunderstorms immediately after lightning they have shapes of giant jellyfish carrots or columns and last tens of milliseconds in earth s atmosphere sprites mostly emit in red and blue wavelengths from excited n2 and n2 and span a vertical range between 50 and 90 km above the surface the emission spectra morphology and occurrence heights of sprites reflect the properties of the planetary atmosphere they inhabit and are related to the intensity of the initiating parent lightning this paper presents results of theoretical calculations of the expected occurrence heights of sprites above lightning discharges in the co2 atmosphere of venus the n2 atmosphere of titan and the h2 he atmosphere of jupiter the expected emission features are presented and the potential of detecting sprites in planetary atmospheres by orbiting spacecraft is discussed

oxygen and carbon isotope composition of callovian lower oxfordian middle upper jurassic belemnite rostra from central poland a record of a late callovian global sea level rise abstract oxygen and carbon isotope data of well preserved and stratigraphically well dated belemnite rostra are presented from a callovian lower oxfordian succession of the polish jura chain south central poland that was deposited in a deep shelf environment palaeotemperatures calculated from belemnite 18 o values 9 to 14 c indicate relatively constant climatic conditions during studied callovian and early oxfordian intervals belemnite 13 c temporal trends which are interpreted to record primary variation in the isotope composition of dissolved inorganic carbon reservoir display a prominent positive carbon isotope shift up to around 1 7 vpdb in the upper callovian this excursion is preceded and followed by a drop in average 13 c values of belemnite rostra of around 1 the late callovian carbonate carbon isotope excursion is likely linked to the enhanced storage of organic carbon in shelf sediments during a global sea level rise the presented data are not compatible with the theory of prolonged global glaciation at the middle late jurassic transition

bioerosion in an equatorial middle jurassic coral sponge reef community callovian matmor formation southern israel abstract the matmor formation middle jurassic callovian 165 161 mya in southern israel contains abundant coral sponge patch reefs and large crinoids which have been extensively bioeroded by bivalves worms barnacles phoronids and others producing eight ichnospecies it is significant for the evolutionary history of bioerosion because this is the first equatorial middle jurassic boring ichnofauna to be documented when compared to contemporaneous ichnofaunas this assemblage is of average diversity and abundance but has only rare sponge borings and contains abundant specimens of oichnus paraboloides as shallow pits on crinoid stems the matmor formation surprisingly lacks carbonate hardgrounds which are otherwise abundant in subtropical and temperate equivalents

pollen analysis and 14c age of moss remains in a permafrost core recovered from the active rock glacier murtel corvatsch swiss alps geomorphological and glaciological implications within the framework of core drilling through the permafrost of the active rock glacier murtel corvatsch in the swiss alps subfossil stem remains of seven different bryophyte species were found at a depth of 6 m below surface and about 3 m below the permafrost table in samples from massive ice the composition of the moss species points to the former growth of the recovered mosses in the nearest surroundings of the drill site a total of 127 pollen and spores captured by the mosses and representing 23 taxa were determined the local vegetation during deposition time must be characterized as a moss rich alpine grassland meadow rich in cyperaceae poaceae chenopodiaceae and asteraceae comparable to today s flora present around the study site for l4 c analysis accelerator mass spectrometry had to be used due to the small sample mass about 0 5 mg carbon content the mean conventional 14 c age of 2250 100 years 1 variability corresponds to ranges in the calibrated calendar age of 470 170 bc and 800 bc to ad 0 at statistical probabilities of 68 and 95 respectively this result is compared with the present day flow field as determined by high precision photogrammetry and with information about the thickness vertical structure and flow of the permafrost from borehole measurements total age of the rock glacier as a landform is on the order of 10 4 years the development of the rock glacier most probably started around the onset of the holocene when the area it now occupies became definitely deglaciated the bulk of the ice rock mixture within the creeping permafrost must be several thousand years old characteristic average values are estimated for 1 surface velocities through time cm a 1 2 long term ice and sediment accretion rates mm a 1 on the debris cone from which the rock glacier develops 3 retreat rates 1 2 mm a 1 of the cliff which supplies the debris to the debris cone and rock glacier and 4 ice content of the creeping ice rock mixture 50 90 by volume the pronounced supersaturation of the permafrost explains the steady state creep mode of the rock glacier

preliminary results from the sprites94 aircraft campaign 1 red sprites the dual jet aircraft sprites94 campaign yielded the first color imagery and unambiguously triangulated physical dimensions and heights of upper atmospheric optical emissions associated with thunderstorm systems low light level television images in both color and in black and white b w obtained during the campaign show that there are at least two distinctively different types of optical emissions spanning part or all of the distance between the anvil tops and the ionosphere the first of these emissions dubbed sprites after their elusive nature are luminous structures of brief 16 ms duration with a red main body that typically spans the altitude range 50 90 km and possessing lateral dimensions of 5 30 km faint bluish tendrils often extend downward from the main body of sprites occasionally appearing to reach cloud tops near 20 km in this paper the principal characteristics of red sprites as observed during the sprites94 campaign are described the second distinctive type of emissions blue jets are described in a companion paper wescott et al this issue

perturbation of the carbon cycle at the middle late jurassic transition geological and geochemical evidence a compilation of new and published stratigraphic paleontological and geochemical data is used to detect the reciprocal influences of carbon cycling and global environmental changes in the jurassic a major perturbation of the surface carbon cycling accompanied by pronounced climate and sea level fluctuations waxing and waning of continental ice affected earth history around the middle late jurassic transition mljt we establish the respective timing of changes of carbonate and organic matter sedimentation and global fluctuations of sea surface temperatures paleobiogeography and o isotope paleothermometry and sea level sequence stratigraphy so that causative mechanisms and feedback effects can be considered it is apparent that the global sea level rise and warming initiated in the late bathonian led to a constriction of carbonate platforms to low latitudes and enhanced marine organic deposition sea level and temperature optima were achieved several million years later during the middle callovian a detailed record of sea surface temperatures in the northern hemisphere based on migration of marine fauna and isotopic thermometry indicates that a drastic climatic decline set in during the early late callovian just post dating the increased capture of organic matter by marine sediments this decline in temperature is interpreted in terms of an inverse greenhouse effect triggered by drawdown of co 2 consequent upon excess carbon burial the magnitude of refrigeration and its coincidence in time with an abrupt global scale fall of sea level are both suggestive of continental ice formation at this time carbonate sedimentation was jeopardized at the mljt as a result of both global cooling and presumed p c o 2 lowering and resumed abruptly during the middle oxfordian by spreading again over mid latitude zones salient conclusions are that 1 the pattern of excess carbon burial coincident with elevated temperature but followed by climatic deterioration supports the general hypothesis that a major control on mesozoic climate was the abundance of atmospheric co 2 2 significant masses of continental ice may have formed during this part of the jurassic and correlatively high co 2 levels were certainly not sustained throughout this period 3 the global carbonate sedimentation budget correlated with the surface temperature and sea level but the latitudinal spreading of type tropical carbonates was not simply related to the thermal status of seawaters 4 on a global scale the c o r g and c i n o r g burial rates were coupled apparently through the correlation existing between the co 2 level and surface temperature

television image of a large upward electrical discharge above a thunderstorm system an image of an unusual luminous electrical discharge over a thunderstorm 250 kilometers from the observing site has been obtained with a low light level television camera the discharge began at the cloud tops at 14 kilometers and extended into the clear air 20 kilometers higher the image which had a duration of less than 30 milliseconds resembled two jets or fountains and was probably caused by two localizd electric charge concentrations at the cloud tops large upward discharges may create a hazard for aircraft and rocket launches and by penetrating into the ionosphere may initiate whistler waves and other effects on a magnetospheric scale such upward electrical discharges may account for unexplained photometric observations of distant lightning events that showed a low rise rate of the luminous pulse and no electromagnetic sferic pulse of the type that accompanies cloud to earth lightning strokes an unusually high rate of such photometric events was recorded during the night of 22 to 23 september 1989 during a storm associated with hurricane hugo

altitude time development of sprites 1 data from sprites using a 16 channel multi anode photometer map have been recorded at 0 1 ms resolution the majority of the sprites have onsets at an altitude of 70 75 km and subsequently propagate both upward and downward from this initial altitude the statistical lifetime of the emissions measured by the blue sensitive map is approximately 1 3 ms the velocities of propagation are between 107 and 108m s 1 with larger velocities being measured at higher altitudes the larger propagation velocities of the upward and downward sprite luminosity channels are consistent with the characteristics of highly over voltage streamers in the mesosphere

fast low level light pulses from the night sky observed with the skyflash program this paper presents further discussion of and new data on fast subvisual increases in the luminosity of the night sky described in our previous papers a detailed technical description of the simple telescopic photometers used in the project skyflash and their mode of operation including the detection of polarized rayleigh scattered flashes is provided distant lightning storms account for many of the events and the complex relations between short and long luminous pulses with and without sferics are shown by examples from a new computerized data system supplemented by two low light level tv cameras of particular interest are the previously observed long events having a slow rise and fall 20 ms duration and showing small polarization and no coincident sferic a group of such events on september 22 23 during the invasion of u s coasts by hurricane hugo is discussed in detail the recently observed plume cloud top to stratosphere lightning event is suggested as a possible source type for these flashes an alternative source may be exploding meteors recently identified during skyflash observations by low light level television techniques as the origin of some sky wide flash events described herein

diverse sclerozoan assemblages encrusting large bivalve shells from the callovian middle jurassic of southern poland a diverse sclerozoan assemblages consisting of both encrusting and boring biota are described from the large limid bivalves ctenostreon from the callovian hardground setting of zalas in southern poland at least 27 encrusting and seven bioerosion taxa are reported here which makes this assemblage not only one of the most diverse in the middle jurassic but the richest in encrusting taxa from the callovian the encrusters consist of cryptic biota of which sedentary polychaetes and cyclostome bryozoans dominate with respect to both species number and abundance the bioerosion traces are dominated by tiny pits referred to the ichnogenus oichnus probably made by some soft bodied biota in the present case followed by the borings of acrothoracican barnacles rogerella the first colonizers of the bivalve shells probably were borers as they only occur in the host shells the encrusting pioneers presumably were oysters and oyster like bivalves followed by opportunistic serpulid sabellid polychaetes and cyclostome bryozoans the last colonizers were calcisponges and thecideide brachiopods in comparison to the only known late callovian shallow and reef associated tropical sclerozoans of israel the assemblage from the open marine deeper setting of poland is much richer in encrusting taxa such a surprising high encruster diversity in the marine northern paleo latitude may have resulted from the deeper and calmer environment with a both reduced sedimentation rate and algal cover and without any significant salinity changes the factors that are thought to have impacted the tropical and shallow marine sclerozoans from israel

elves lightning induced transient luminous events in the lower ionosphere observations of optical phenomena at high alti tude a bove thunderstorms using a multichannel high speed photometer and image intensified ccd cameras were carried out at yucca ridge field station 40040 n 104o 56 w colorado as part of the sprites 95 campaign from 15 june to august 6 1995 these newneasurements indicate that diffuse optical flashes with a duration of i ms and a hori zontal scale of 100 300 km occur at 75 105 km altitude in the lower ionosphere just after the onset of cloud to ground lightning discharges but preceding the onset of sprites here we designate these events as alves to distinguish them from i ed sprites this finding is consistent with the production of diffuse optical emissions due to the heating of the lower ionosphere by electromagnetic pulses generated by lightning discharges as suggested by several authors

the temporal resolution of epibiont assemblages are they ecological snapshots or overexposures abstract the effects of time averaging on the fossil record of soft substrate marine faunas have been investigated in great detail but the temporal resolution of epibiont assemblages has been inferred only from limited duration deployment experiments individually dated shells provide insight into the temporal resolution of epibiont assemblages and the taphonomic history of their hosts over decades to centuries epibiont abundance and richness were evaluated for 86 dated valves of the rhynchonelliform brachiopod bouchardia rosea collected from the inner shelf maximum abundance occurred on shells less than 400 yr old and maximum diversity was attained within a century taphonomic evidence does not support models of live host colonization net accumulation or erasure of epibionts over time encrustation appears to have occurred during a brief interval between host death and burial with no evidence of significant recolonization of exhumed shells epibiont assemblages of individually dated shells preserv

relict rock glaciers as indicators of mediterranean palaeoclimate during the last glacial maximum late wurmian in northwest greece relict rock glaciers have been identified and mapped in the high cirques of mount tymphi in the pindus mountains of northwest greece they are periglacial forms and represent the most recent cold stage landforms in an area that displays widespread evidence of pleistocene glaciation it is likely that these features formed during the last glacial maximum late wurmian as talus rock glaciers and beneath small cirque glaciers as debris rock glaciers comparisons with modern rock glacier climate relationships suggests mean annual temperatures of ca 8 9 c lower than present at their time of formation this temperature reconstruction is in good agreement with recent palaeoclimatic reconstructions for the northern mediterranean based on a general circulation model moreover as rock glaciers are typical of cold and relatively dry mountain regions their presence is consistent with palaeobotanical and lake level data suggesting a cold and relatively dry climate for the last glacial maximum in greece however the presence of small cirque glaciers above some rock glaciers suggests that although precipitation must have been low enough to preclude glacier extension down to lower altitudes it was not so low as to inhibit glacier formation entirely copyright 2003 john wiley sons ltd

growth of ferruginous oncoliths in the bajocian middle jurassic of europe limonitic oncoliths from the bajocian of europe widely known as snuff boxes grew by accretion of bundles of laminae on one side followed by overturning and accretion of laminae on the other side a diverse hard substrate encrusting fauna grew interleaved with the ferruginous laminations the palaeoecological preferences of this fauna indicate that its growth and hence the accumulation of the laminations took place on the gloomy undersides of the oncoliths this upsidedown growth is supported by characteristics of the lamination bundles themselves and by the predominant present day orientations of the snuff boxes the abundance of the associated fauna and the lack of carbonate dissolving macroborers cutting the laminae suggest an original ferric composition precipitation was probably under the control of non photosynthetic microorganisms that inhabited the microenvironments represented by the oncoliths lower surfaces

a new equatorial very shallow marine sclerozoan fauna from the middle jurassic late callovian of southern israel abstract tropical jurassic sclerozoan faunas are poorly known yet they are critical to our understanding of jurassic biogeography and the evolution of hard substrate communities a diverse assemblage of hard substrate fossils is here described from subunits 53 and 54 of the upper matmor formation callovian of hamakhtesh hagadol in the negev desert of southern israel this region was on or very near the equator during the middle jurassic the fauna is dominated by flat platter shaped sponges actostroma and scleractinian corals microsolena some of which have the depressed centers and raised rims of microatolls which form today in the shallowest subtidal zone associated with reef systems the coral and calcareous sponge platters are encrusted on their top surfaces by one species of serpulid worm and many small coral and sponge recruits with narrow attachments and mushroom shaped or conical skeletons growing upwards the undersurfaces of the platters are encrusted by another serpulid species at least two calcareous sponges rare cyclostome bryozoans oysters plicatulid bivalves and numerous thecideide brachiopods the first known from the jurassic of the region the upper and undersurfaces of the platters are often bored by bivalves forming the ichnospecies gastrochaenolites torpedo these borings were occasionally reoccupied by a nestling mytilid bivalve on the undersurfaces of the skeletal platters this encrusting fauna of the matmor formation apparently lived in a shallow lagoon on the landward side of a coral reef the fossils in the surrounding muddy sediments are primarily echinoids oysters and rhynchonellid and terebratulid brachiopods this sclerozoan fauna is an evidence that jurassic tropical hard substrate faunas were serpulid rich and bryozoan poor as predicted but more diverse at twelve species than expected this community was also ecologically divided into open and cryptic assemblages like its jurassic equivalents in the temperate and subtropical waters of europe and north america

mountain permafrost development and challenges of a young research field an overview is given of the relatively short history important issues and primary challenges of research on permafrost in cold mountain regions the systematic application of diverse approaches and technologies contributes to a rapidly growing knowledge base about the existence characteristics and evolution in time of perennially frozen ground at high altitudes and on steep slopes these approaches and technologies include 1 drilling borehole measurement geophysical sounding photogrammetry laser altimetry gps sar surveying and miniature temperature data logging in remote areas that are often difficult to access 2 laboratory investigations e g rheology and stability of ice rock mixtures 3 analyses of digital terrain information 4 numerical simulations e g subsurface thermal conditions under complex topography and 5 spatial models e g distribution of permafrost where surface and microclimatic conditions are highly variable spatially a sound knowledge base and improved understanding of governing processes are urgently needed to deal effectively with the consequences of climate change on the evolution of mountain landscapes and especially of steep mountain slope hazards as the stabilizing permafrost warms and degrades interactions between glaciers and permafrost in cold mountain regions have so far received comparatively little attention and need more systematic investigation

on the thermal regime of an arctic valley glacier a study of white glacier axel heiberg island n w t canada from 1974 to 1981 a total of 32 bore holes was drilled on white glacier and vertical ice temperature profiles measured the data obtained allowed the construction of three longitudinal and four transverse profiles of the two dimensional temperature distributions thus an extensive layer of temperate or near temperate ice was discovered close to the bedrock in the lowest part of the glacier tongue it was also found that the temperature distribution cannot be in a steady state since there is a temperature minimum 100 150 m below the glacier surface in the accumulation area a simple numerical model calculation shows that this minimum can be mostly explained by the general climatic warming since 1880 the 10 m temperatures show diffuse relations to climatic conditions and balance zones a simple scheme for extrapolating surface temperatures is discussed

observation of sprites over the asian continent and over oceans around taiwan 1 sprites were observed over thunderstorms in the southern china and in oceans around taiwan the observation sites were on the ali mountain of taiwan s central ridge area with an altitude of 2413 m and in the campus of national cheng kung university with an altitude of 50 m for the observed land sprites 90 of them were either carrots or columniforms and 64 of the sprites occurred in groups among the observed oceanic sprites 89 of them were carrots but only 22 of the sprites occurred in groups we define a sprite active system as a thunderstorm that continuously produces at least one sprite in a 10 minute interval the active sprites generating periods for the observed thunderstorms were typically shorter than 30 minutes the sprite production rates for these asian thunderstorms are estimated to be between i 2 10 4 events km2 hr and i 1 10 3 events km2 hr

sprite observations in the northern territory of australia sprites a form of brief luminous discharge in the upper atmosphere above a thunderstorm were observed and imaged on two video cameras in australia s northern territory these were the first such ground based observations made outside the united states sprite discharges typically took place between the altitudes of 50 km and 80 km and spanned an average width of 44 km many of the sprite events were of long duration with an average of 145 ms these spatial and temporal features were similar to those observed from the ground and the air in the united states during the longer events some luminous discharge elements were observed to decay as other new elements formed as the new elements were often laterally displaced from the old the sprites sometimes appeared to dance across the sky this phenomenon has been observed in colorado and named dancing sprites the lateral progression of sprite elements observed in the northern territory was overwhelmingly in one direction and covered distances of up to 90 km

a 10 300 year old permafrost core from the active rock glacier lazaun southern otztal alps south tyrol northern italy two cores were drilled on rock glacier lazaun in the southern otztal alps n italy the average ice content of core lazaun i is 43 vol and of core lazaun ii is 22 vol radiocarbon dating of plant macrofossil remains of core lazaun i yielded ages ranging from 8960 cal yr bp at a depth of ca 23 5 m to 2240 cal yr bp at a depth of 2 8 m indicating that the ice near the base is approximately 10 300 yr old the rock glacier was intact since that time and the ice persisted even during warm periods of the holocene an ice free debris layer between 16 8 and 14 7 m separates the rock glacier into two frozen bodies inclinometer measurements indicate that both frozen bodies are active and that deformation occurs within a shear horizon at a depth of 20 25 m at the base of the lower frozen body and to a minor extent at a depth of approximately 14 m at the base of the upper frozen body the ice free debris layer in the middle of the lazaun rock glacier indicates a more than five centennial long drought period which dates to about 4300 3740 cal yr bp

recent warming of mountain permafrost in svalbard and scandinavia 1 three deep boreholes 100 m in mountain permafrost were recently drilled in svalbard janssonhaugen and in scandinavia tarfalaryggen and juvvasshoe for long term permafrost monitoring these holes form part of a latitudinal transect of boreholes in permafrost through europe established by the permafrost and climate in europe pace project six year thermal time series data collected from the three boreholes are presented these data provide the first opportunity for temporal trends in permafrost temperatures in svalbard and scandinavia to be analyzed results show that the permafrost has warmed considerably at all three sites significant warming is detectable down to at least 60 m depth and present decadal warming rates at the permafrost surface are on the order of 0 04 0 07 c yr 1 with greatest warming in svalbard and in northern scandinavia the present regional trend shows accelerated warming during the last decade

plate tectonic evolution of the southern margin of eurasia in the mesozoic and cenozoic abstract thirteen time interval maps were constructed which depict the triassic to neogene plate tectonic configuration paleogeography and general lithofacies of the southern margin of eurasia the aim of this paper is to provide an outline of the geodynamic evolution and position of the major tectonic elements of the area within a global framework the hercynian orogeny was completed by the collision of gondwana and laurussia whereas the tethys ocean formed the embayment between the eurasian and gondwanian branches of pangea during late triassic early jurassic times several microplates were sutured to the eurasian margin closing the paleotethys ocean a jurassic cretaceous north dipping subduction boundary was developed along this new continental margin south of the pontides transcaucasus and iranian plates the subduction zone trench pulling effect caused rifting creating the back arc basin of the greater caucasus proto south caspian sea which achieved its maximum width during the late cretaceous in the western tethys separation of eurasia from gondwana resulted in the formation of the ligurian penninic pieniny magura ocean alpine tethys as an extension of middle atlantic system and a part of the pangean breakup tectonic system during late jurassic early cretaceous times the outer carpathian rift developed the opening of the western black sea occurred by rifting and drifting of the western central pontides away from the moesian and scythian platforms of eurasia during the early cretaceous cenomanian the latest cretaceous paleogene was the time of the closure of the ligurian pieniny ocean adria alcapa terranes continued their northward movement during eocene early miocene times their oblique collision with the north european plate led to the development of the accretionary wedge of the outer carpathians and its foreland basin the formation of the west carpathian thrusts was completed by the miocene the thrust front was still propagating eastwards in the eastern carpathians during the late cretaceous the lesser caucasus sanandaj sirjan and makran plates were sutured to the iranian afghanistan plates in the caucasus caspian sea area a north dipping subduction zone jumped during paleogene to the scythian turan platform the shatski terrane moved northward closing the greater caucasus basin and opening the eastern black sea the south caspian underwent reorganization during oligocene neogene times the southwestern part of the south caspian basin was reopened while the northwestern part was gradually reduced in size the collision of india and the lut plate with eurasia caused the deformation of central asia and created a system of nw se wrench faults the remnants of jurassic cretaceous back arc systems oceanic and attenuated crust as well as tertiary oceanic and attenuated crust were locked between adjacent continental plates and orogenic systems

recent observations of lightning discharges from the top of a thundercloud into the clear air above a note of inquiry published in a magazine read by airplane pilots has elicited 15 new observations of a rare form of lightning that comes out of the cloud top goes up vertically and terminates in the clear air above these confirm previous observations showing that this phenomenon usually occurs above very large and energetic thunderclouds however small clouds with tops at 15 000 ft mean sea level 5000 m have been observed to exhibit this rare form of lightning also one of the more spectacular observations was made over the severe storm system that produced the devastating tornadoes of april 11 1965

blue starters brief upward discharges from an intense arkansas thunderstorm this paper documents the first observations of a new stratospheric electrical phenomenon associated with thunderstorms on the night of 30 june ut 1 july 1994 30 examples of these events which we have called blue starters were observed in a 6 m 44 s interval above the very energetic arkansas thunderstorm where blue jets were first observed the blue starters are distinguished from blue jets by a much lower terminal altitude they are bright and blue in color and protrude upward from the cloud top 17 18 km to a maximum 25 5 km 83 655 ft in altitude all blue starters events were recorded from two small areas near texarkana texas arkansas where hail 7 0 cm in diameter was falling comparison to cloud to ground cg lightning flashes revealed 1 blue starters were not observed to be coincident with either positive or negative cg flashes but they do occur in the same general area as negative cg flashes 2 cumulative distributions of the negative cg flashes in 5 s before and after the starter and within a radius of 50 km shows a significant reduction for about 3 s following the event in the two cells where starters and jets were observed the energy deficit is approximately 109 j it is possible that blue starters are a short lived streamer phenomenon

triangulation of sprites associated halos and their possible relation to causative lightning and micrometeors sprite halos were recently identified as an impulsive but spatially diffuse phenomenon that sometimes occurs just prior to but distinct from sprites the lack of discernible spatial structure and the temporal development sequence in halos differs markedly from the highly structured bodies and tendrils and the complex development sequences of sprites however both phenomena are thought to result from an electric field due to charge moment changes usually associated with large positive cloud to ground cg lightning but also following negative cg flashes three dimensional triangulations of sprites and sprite halos were made between stations in south dakota and wyoming in august 1999 during the nasa sprites99 balloon campaign halos were found to have a gaussian 1 e diameter of 66 km and 1 e thickness of 4 km comparison with the location of the underlying lightning strokes as recorded by the national lightning detection network nldn confirms that the horizontal position of sprites may be laterally offset by as much as 50 km from the underlying parent lightning discharge as has been previously reported the point of maximum apparent brightness for sprite halos occurs at an altitude of 78 km similar to that of sprites however unlike sprites this point tends to be centered directly above the underlying parent lightning discharge 4 6 2 7 km mean distance from the center of the halo to the nldn location this difference in spatial location relative to the underlying lightning suggests that the electrical breakdown associated with discrete sprites may require a random ionizing event such as a micrometeor in contrast sprite halos do not appear to require such a random component

palaeoecology and evolution of marine hard substrate communities abstract marine organisms have occupied hard substrates since the archaean shells rocks wood and sedimentary hardgrounds offer relatively stable habitats compared to unconsolidated sediments but the plants and animals which inhabit them must develop means to gain and defend this premium attachment space hard substrate communities are formed by organisms with a variety of strategies for adhering to and or excavating the substrates they inhabit while mobile grazers organically attached and even soft bodied organisms may leave evidence of their former presence in ancient hard substrate communities a superior fossil record is left by sessile encrusters with mineralised skeletons and by borers which leave trace fossils furthermore encrusters and borers are preserved in situ retaining their spatial relationships to one another and to the substrate spatial competition ecological succession oriented growth and differential utilisation of exposed vs hidden substrate surfaces can all be observed or inferred hard substrate communities are thus excellent systems with which to study community evolution over hundreds of millions of years here we review the research on modern and ancient hard substrate communities and point to some changes that have affected them over geological time scales such changes include a general increase in bioerosion of hard substrates particularly carbonate surfaces through the phanerozoic this is at least in part analogous to the infaunalisation trends seen in soft substrate communities encrusting forms show an increase in skeletalisation from the palaeozoic into the mesozoic and cenozoic which may be a response to increasing levels of predation hard substrate communities considering borers and encrusters together show a rough increase in tiering through the phanerozoic which again parallels trends seen in soft substrate communities this extensive review of the literature on living and fossil hard substrate organisms shows that many opportunities remain for large scale studies of trends through time at the community and clade levels palaeontologists will especially benefit by closer integration of their work with that of neontologists particularly in aspects of ecology such as larval recruitment competition and succession

implications of lightning charge moment changes for sprite initiation 1 we report impulse lightning charge moment changes defined as occurring in the first 2 ms after return stroke onset in all cloud to ground lightning strokes detected by the national lightning detection network in three storms during which above thunderstorm sprite video was recorded after analyzing strokes that both did and did not produce sprites and carefully accounting for lightning sprite delay times we found that sprite initiation on all three nights is consistent with a sharp charge moment threshold essentially all charge moment changes above and none below this threshold produced sprites with short delays 5 ms from the source lightning on two nights this threshold was approximately 600 c km and on the other it was approximately 350 c km this internight variability is probably due to expected variability in the nighttime mesospheric conductivity and the thresholds themselves are consistent with predictions of conventional breakdown theory additionally we found only one negative polarity lightning stroke from all three storms that exceeded this threshold indicating that the rarity of documented sprites produced by negative strokes may be largely explained by the lack of sufficiently big negative strokes in the u s high plains

sprites triggered by negative lightning discharges high altitude air breakdown manifested as red sprites is reported in close association with negative cloud to ground lightning cg on at least two occasions above an unusual storm on august 29 1998 data from high speed photometry low light level video and receivers of lightning electromagnetic signatures in the frequency range 10 hz to 20 khz are used to establish the association and indicate that the causative cg discharges effected unusually large vertical charge moment changes mqv of up to 1550 c km in 5 ms the existence of sprites caused by cg s rather than the regularly associated cg s has immediate implications for sprite models and observations

epibiont shadowing a hitherto unrecognized way of preserving soft bodied fossils outlines of soft bodied sessile epibionts that grew attached to the surfaces of calcareous shells in ancient seas are sometimes preserved by a process termed epibiont shadowing processes that altered the surface of the shell were prevented from happening immediately beneath the attached epibiont leaving a shadow of its attachment site following its death and decay microboring around the perimeter of the epibiont by presumed endolithic cyanobacteria gave rise to endolithic shadows and dissolution of the calcareous substrate maybe beneath larger smothering organisms produced solution shadows of smaller organisms that protected their sites of attachment from such etching effects recognition of this type of preservation allows the stratigraphic range of certain soft bodied groups to be extended details of the shadows may yield information about the morphological construction of the groups in question

engineering geomorphology of rock glaciers a partnership between geomorphology and engineering is facilitating human development in this harsh environment rock glaciers provide locations for urban water sources construction borrow sources drill sites shaft and tunnel portals ski tower supports and dam abutments rock glaciers as dynamic landforms necessitate proper identification in the field placing structures on in or adjacent to rock glaciers requires an appreciation and understanding of their temporal stability internal and surface characteristics provide important clues to the development and deformation of rock glaciers rock glaciers play a significant role in the alpine debris transport system active movement and mass wasting are perhaps the most obvious geologic hazards affecting engineered works the structure of the rock glacier is conducive to the production of a steady continuous supply of meltwater during summer months thus rock glaciers serve as alpine aquifers consideration of rock glaciers as potential aquifer sources requires caution because of the long term impact of climate change on the temporal nature of the landform from the rock glaciers that we have monitored for water quality characteristics it appears that they provide quality potable water this paper provides a foundation for appreciation and understanding of rock glaciers from an engineering geomorphologic point of view the approach taken in this paper provides practical important information to aid the engineer and engineering geologist in prudent evaluations of rock glaciers as potential sites for human development and uses the bottom line of our paper is rock glaciers must be avoided for essentially all structures

sprite observations above the u s high plains in relation to their parent thunderstorm systems transient luminous events sprites blue jets elves above large mesoscale convective systems mcss over the u s high plains have been routinely monitored from the yucca ridge field station near fort collins colorado using ground based low light video systems we analyzed 36 sprites above the nebraska mcs of august 6 1994 the results lend further support to the hypothesis that sprites are almost uniquely associated with positive cloud to ground cg lightning flashes sprite associated cgs also averaged substantially larger peak currents than the remaining cg population 81 ka versus 30 ka in this storm system there is some evidence that sprite associated cgs also have higher stroke multiplicity this study yields no evidence of sprites associated with negative cg events in the central united states an additional requirement appears to be that the parent mcs has a contiguous radar reflectivity area exceeding 20 25 000 km 2 the majority of the sprites occur above the large stratiform precipitation region and not the high reflectivity convective core of the mcs triangulation of a limited number of paired images from september 7 1994 suggests that the sprite is generally centered within 50 km of the parent cg assuming the cg provides the range single image photogrammetric analyses provide estimates of the maximum vertical extent of the sprites for this storm the sprite tops averaged 77 km with a maximum of 88 km the bases averaged 50 km but with a few sprite tendrils extending as low as 31 km

secular oscillations in the carbonate mineralogy of reef building and sediment producing organisms driven by tectonically forced shifts in seawater chemistry the primary mineralogy of oolites and early marine carbonate cements led sandberg nature 305 1983 19 22 to divide the phanerozoic eon into three intervals of aragonite seas and two intervals of calcite seas hardie geology 24 1996 279 283 has shown that these oscillations together with synchronous oscillations in the mineralogy of marine potash evaporites can be explained by secular shifts in the mg ca ratio of seawater driven by changes in spreading rates along mid ocean ridges the hardie model also predicts that high mg calcite should precipitate along with aragonite as it does in today s aragonite sea we have uncovered oscillations in the carbonate mineralogy of hypercalcifying organisms ones that have produced massive skeletons large reefs or voluminous bodies of sediment that correspond to sandberg s aragonite seas and calcite seas and that are predicted by the hardie model particular groups of corals sponges and algae appear to have been dominant reef builders only when favored by an appropriate mg ca ratio in seawater in early and middle paleozoic calcite seas calcite i reefs were dominated by calcitic tabulate heliolitid and rugose corals and calcitic stromatoporoids in contrast during the period of late paleozoic early mesozoic aragonite seas aragonite ii aragonitic groups of sponges scleractinian corals and phylloid algae as well as high mg calcitic red algae were principal reef builders during late cretaceous time at the acme of calcite ii massive rudists displaced aragonitic hermatypic corals in today s aragonite sea aragonite iii scleractinian corals are again dominant reef builders along with high mg calcitic coralline algae major sediment producing algae exhibit temporal patterns similar to those of reef builders calcitic receptaculitids flourished during calcite i whereas aragonitic dasycladaceans did not become dominant rock formers until aragonite ii during calcite ii calcitic nannoplankton formed massive coccolith chalks in warm shallow seas of the late cretaceous after the mg ca ratio of seawater had reached a very low value and calcium concentration a very high value as the mg ca ratio of seawater rose and calcium concentration fell during the cenozoic era individual coccoliths on average became less massive and encrusted cells less thickly by pliocene time during aragonite iii the prominent genus discoaster secreted only narrow rayed coccoliths that covered less than 25 of the cell surface also during aragonite iii the aragonitic green alga halimeda emerged as the dominant skeletal sediment producer in reef tracts the influence of seawater chemistry on skeletal secretion appears to have been especially strong for morphologically simple taxa that exert relatively weak control over their own calcification such groups include algae sponges corals and bryozoans morphological simplicity also permits these groups to adopt vegetative or colonial modes of growth that confer success in competition for space on reefs this linkage in addition to the basic chemical demands of hypercalcification has given the mg ca ratio of seawater strong control over the success of individual reef building taxa more generally this ratio appears to have strongly influenced evolutionary changes in the skeletal mineralogy of sponges and cheilostome bryozoans throughout their history we conclude that throughout phanerozoic time a chain of causation has extended from mid ocean ridge processes via seawater chemistry to the mineralogical and biological composition of reef communities and bioclastic carbonate deposits

comments on debris covered glaciers in the sierra nevada california and their implications for snowline reconstruction by d h clark m m clark and a r gillespie

characteristics of luminous structures in the stratosphere above thunderstorms as imaged by low light video an experiment was conducted in which an image intensified low light video camera systematically monitored the stratosphere above distant 100 800 km mesoscale convective systems over the high plains of the central u s for 21 nights between 6 july and 27 august 1993 complex luminous structures were observed above large thunderstorm clusters on eleven nights with one storm system 7 july 1993 yielding 248 events in 410 minutes their duration ranged from 33 to 283 ms with an average of 98 ms the luminous structures generally not visible to the naked dark adapted eye exhibited on video a wide variety of brightness levels and shapes including streaks aurora like curtains smudges fountains and jets the structures were often more than 10 km wide and their upper portions extended to above 50 km msl

electrical discharge from a thundercloud top to the lower ionosphere for over a century numerous undocumented reports have appeared about unusual large scale luminous phenomena above thunderclouds1 2 3 4 5 6 and more than 80 years ago it was suggested that an electrical discharge could bridge the gap between a thundercloud and the upper atmosphere7 8 since then two classes of vertically extensive optical flashes above thunderclouds have been identified sprites9 10 11 and blue jets12 13 14 sprites initiate near the base of the ionosphere develop very rapidly downwards at speeds which can exceed 107 m s 1 ref 15 and assume many different geometrical forms16 17 18 19 in contrast blue jets develop upwards from cloud tops at speeds of the order of 105 m s 1 and are characterized by a blue conical shape12 13 14 but no experimental data related to sprites or blue jets have been reported which conclusively indicate that they establish a direct path of electrical contact between a thundercloud and the lower ionosphere here we report a video recording of a blue jet propagating upwards from a thundercloud to an altitude of about 70 km taken at the arecibo observatory puerto rico above an altitude of 42 km normally the upper limit for blue jets and the lower terminal altitude for sprites the flash exhibited some features normally observed in sprites as we observed this phenomenon above a relatively small thunderstorm cell we speculate that it may be common and therefore represent an unaccounted for component of the global electric circuit

coordinated analysis of delayed sprites with high speed images and remote electromagnetic fields 1 simultaneous measurements of high altitude optical emissions and magnetic fields produced by sprite associated lightning discharges enable a close examination of the link between low altitude lightning processes and high altitude sprite processes we report results of the coordinated analysis of high speed sprite video and wideband magnetic field measurements recorded simultaneously at yucca ridge field station and duke university from june to august 2005 sprites were detected following 67 lightning strokes all of which had positive polarity our data showed that 46 of the 83 discrete sprite events in these sequences initiated more than 10 ms after the lightning return stroke and we focus on these delayed sprites in this work all delayed sprites were preceded by continuing current moments that averaged at least 11 ka km between the return stroke and sprites the total lightning charge moment change at sprite initiation varied from 600 to 18 600 c km and the minimum value to initiate long delayed sprites ranged from 600 for 15 ms delay to 2000 c km for more than 120 ms delay we numerically simulated electric fields at altitudes above these lightning discharges and found that the maximum normalized electric fields are essentially the same as fields that produce short delayed sprites both estimated and simulation predicted sprite initiation altitudes indicate that long delayed sprites generally initiate around 5 km lower than short delayed sprites the simulation results also reveal that slow 5 20 ms intensifications in continuing current can play a major role in initiating delayed sprites

observations of two sprite producing storms in colorado two sprite producing thunderstorms were observed on 8 and 25 june 2012 in northeastern colorado by a combination of low light cameras a lightning mapping array polarimetric and doppler radars the national lightning detection network and charge moment change measurements the 8 june event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h the majority of sprites occurred during a lull in convective strength as measured by total flash rate flash energy and radar echo volume mean flash area spiked multiple times during this period however total flash rates still exceeded 60 min sup 1 and portions of the storm featured a complex anomalous charge structure with midlevel positive charge near 20degc the storm produced predominantly positive cloud to ground lightning all sprite parent flashes occurred on the northeastern flank of the storm where strong westerly upper level flow was consistent with advection of charged precipitation away from convection providing a pathway for stratiform lightning the 25 june event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h the sprites again occurred during a convective lull with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area however all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud the results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms

permafrost heat flow and the geothermal regime at prudhoe bay alaska temperature measurements through permafrost in the oil field at prudhoe bay alaska combined with laboratory measurements of the thermal conductivity of drill cuttings permit an evaluation of in situ thermal properties and an understanding of the general factors that control the geothermal regime a sharp contrast in temperature gradient at approx 600 m represents a contrast in thermal conductivity caused by the downward change from interstitial ice to interstitial water at the base of permafrost under near steady state conditions interpretation of the gradient contrast in terms of a simple mode for the conductivity of an aggregate yields the mean ice content approx 39 and thermal conductivities for the frozen and thawed section 8 1 and 4 7 mcal cm s sup 0 c respectively these results yield a heat flow of approx 1 3 hfu which is similar to other values on the alaskan arctic coast the anomalously deep permafrost is a result of the anomalously high conductivity of the siliceous ice rich sediments curvature in the upper 160 m of the temperature profiles represents a warming of approx 1 8 sup 0 c of the mean surface temperature and a net accumulation of 5 6 kcal cm sup 2 by the solid earth surface during the last 100 years or so rising sea levelmore and thawing of ice rich sea cliffs probably caused the shoreline to advance tens of kilometers in the last 20 000 years inundating a portion of the continental shelf that is presently the target of intensive oil exploration a simple conduction model suggests that this recently inundated region is underlain by near melting ice rich permafrost to depths of 300 500 m its presence is important to seismic interpretations in oil exploration and to engineering considerations in oil production with confirmation of the permafrost configuration by offshore drilling heat conduction models can yield reliable new information on the chronology of arctic shorelines less

global sprite occurrence locations and rates derived from triangulation of transient schumann resonance events 1 we estimated locations and rates of sprite occurrences on a global scale using 1 100 hz elf magnetic field waveform data obtained at syowa station in antarctica and onagawa observatory in japan from the elf data obtained in a period between june 19 2001 and january 20 2002 we identified 715 500 events of transient schumann resonances srs the locations and polarizations of these parent cloud to ground cg discharges were determined by a triangulation method the charge moments of these cg discharges were calculated with a normal mode expansion model of sr waves from these results and the empirical sprite initiation probability reported by hu et al 2002 the global occurrence rate of sprites is estimated to be about 720 events day on average it is also found that the active regions of sprite occurrences are located in north and south america africa and south east asia

periglacial geomorphology in the 21st century abstract periglacial geomorphology defined in a classical manner experiences at the moment a strong development nevertheless there remain weaknesses which are often derived from the fact that the clear laws of physics are seldom fully applied in the open non isolated systems under discussion in the next century important tasks in periglacial geomorphic research are the development of a better understanding of the physical nature of periglacial processes of the relationships between periglacial processes and landforms of former present and of future periglacial environments based on reliable models the future of periglacial geomorphology is exciting because it has to predict the environmental changes which occur in high latitude and high altitude periglacial geosystems if the present models of climatic changes are correct this provides challenging possibilities for broad scale geomorphic prediction and experimentation

facies variations across the middle upper jurassic boundary in western europe and the relationship to sea level changes abstract a facies analysis of callovian oxfordian boundary beds has been carried out on numerous sections across western europe with the aim of constructing marine bathymetric curves for each geographic area onshore outcrops in northwest and northeast scotland and borehole cores from the beatrice field in the inner moray firth basin were studied virtually all the sediments are siliciclastic and often thick an early callovian transgression is recorded from skye and northeast scotland but the influence of local tectonics limits the lateral extent of distinctive lithological units within england the callovian succession differs considerably from that found elsewhere the most interesting unit is the upper callovian hackness rock a condensed bed with chamositic ooids which is thought to signify deposition at a time of rising relative sea level the basal oxfordian contains an organic rich clay that may reflect a period of maximum flooding associated with anoxic conditions and the clays above are likely to have been deposited during the ensuing regression in central and southern england the callovian oxfordian boundary occurs within the oxford clay the change from the lower to the middle oxford clay middle upper callovian boundary marks a regional shallowing of the sea signified by higher silt and kaolinite content while the topmost callovian the lamberti limestone is condensed and marks a time of relatively high sea level with a fall in the proportion of kaolinite four regions in france were studied normandy poitou burgundy and ardeche the normandy succession is very similar to that in dorset with the stage boundary occurring at the junction of two clay formations a period of maximum flooding occurred at this boundary before initial regression in the early oxfordian resulted in a renewed terrigenous input the other regions generally have a very condensed calcareous callovian often with a pelagic character the condensed iron ooidal limestones of the spanish iberian chain were deposited in a relatively deep water offshore setting the majority of sections record a phase of severe sediment starvation during the latest callovian and earliest oxfordian zones which are likely to reflect a period of maximum flooding in the swiss jura the most significant period of negligible sedimentation rates occurred in the two zones across the stage boundary clear deepening or shallowing trends cannot readily be recognised in the offshore succession of the swabian alb the comparison of a series of bathymetric curves has led to the recognition of regional sea level events in western europe during the callovian early oxfordian interval a regional sea level rise occurred during the middle and late callovian reaching its greatest extent in the latest callovian lamberti zone and highstand conditions and incipient sea level fall characterised the early oxfordian a literature review of boundary beds in seven further regions from five continents has shown that a middle callovian sea level rise and late callovian early oxfordian phase of high sea level can be recognised on a global scale the european regional sea level changes are therefore considered to be eustatic in origin and probably related to sea floor spreading in the atlantic a eustatic curve has been constructed and compared with two other such curves it differs from that of hallam also based on the facies analysis technique but is quite similar to that of exxon workers based on sequence stratigraphic concepts