minor and trace element partitioning between immiscible ocelli matrix pairs from lamprophyre dikes and sills monteregian hills petrographic province quebec many lamprophyre dike and sill rocks in the monteregian hills petrographic province of southwestern quebec contain felsic segregations ocelli which have been interpreted as globules of immiscible liquid philpotts 1976 ocelli and matrix material were separated from a number of these rocks and analyzed for major and trace elements the major element data when plotted on a greig diagram outline a field of possible silicate liquid immiscibility at higher alumina alkali content than that previously mapped in iron rich experimental systems the trace element data support a liquid immiscibility hypothesis for the formation of these ocelli since high charge density cations are preferentially concentrated in the matrix mafic material a result which is consistent with theoretical and experimental studies

globular ferropicritic rocks at pechenga kola peninsula russia liquid immiscibility versus alteration abstract the uppermost volcanic unit of the early proterozoic pechenga group comprises ferropicritic volcanic and hypabyssal rocks which possess well developed light weathering globular up to 10 cm in size or layer like structures mesoscopicly similar to those found in some archean ocellar komatiites these structures are superficially reminiscent of features attributed to liquid immiscibility including spheroidal aggregates in all stages of coalescence however several lines of field microscopical mineralogical and chemical evidence argue against the immiscibility hypothesis these include identical modal proportions grain sizes morphologies and orientations of crystalline phases in the globules and matrix as strikingly demonstrated for example by the spinifex textured varieties of the globular rocks a solid state hydrothermal metamorphic diffusional process that affected the originally glassy mesostasis is concluded to be the only feasable mechanism for the formation of the globular structures in the pechenga ferropicrites

empirical model of 90 120 km horizontal winds from wind imaging interferometer green line measurements in 1992 1993 an empirical model of horizontal winds is developed based on wind imaging interferometer windii green line observations between 90 and 120 km in 1992 1993 the model includes mean winds solar diurnal and semidiurnal tides and some planetary wave components as well as annual and semiannual variations in these fields its formulation is similar to that of hwm 90 and hwm 93 of hedin et al 1991 1996 but greatly modified and extended to use the higher resolution global wind measurements now available from windii while the technique will only reach fruition when results can be combined from the wind measurements of several years by the different instruments on the uars satellite this interim but updated model provides improved representation of the temporal and geographic variations of the wind fields compared to the current reference models the model generated climatological mean wind diurnal tides and some samples of the entire wind motion fields are presented and compared with the windii measurements and analysis results obtained from the data sets by different methods to check the consistencies between the model representations and the observations this study also reveals a dual cell structure in the meridional component of the diurnal tides with two amplitude maxima centered around 95 and 102 km near 20 latitude and strongly symmetric about the equator at equinox large interannual variabilities are found to exist in both diurnal wind components with maximum amplitudes of 40 and 55 m s for the zonal and meridional respectively at the vernal equinox of 1992

structure of the nonmigrating semidiurnal tide above antarctica observed from the timed doppler interferometer 1 spatial structure and temporal evolution of the nonmigrating semidiurnal tidal components over antarctica are determined by analyzing horizontal wind measurements in the mesosphere and lower thermosphere mlt collected using timed doppler interferometer tidi on the nasa thermosphere ionosphere mesosphere energetics and dynamics timed satellite from 2002 to 2007 the data were organized into six specific intervals of approximately 60 days corresponding to the timed yaw periods the results confirm the existence of a westward propagating zonal wave number 1 w1 semidiurnal tidal component in the antarctic mlt meridional wind field prior to the austral summer solstice this wave achieves a peak amplitude near 20 m s 1 at 90 km and is vertically stratified while extending latitudinally from the pole to 60 s a similar structure is observed in the zonal wind field however the amplitude maximizes around the austral summer solstice during the yaw period spanning 15 november to 15 january in addition to a strong latitudinal gradient in amplitude the w1 component also shows a vertical wavelength from 20 km near the pole to 40 km at 60 s the amplitude and phase agree well with ground based meteor radar observations from the south pole evidence for significant though weaker standing s0 and w3 components is also found these components diminish in the vicinity of the pole and appear during the winter months with latitudinally restricted structures the vertical wavelength of the s0 component during the summer is 25 km similar to the w1 component during the winter the wavelength of the s0 component becomes nearly evanescent

solution properties of rare earth elements in silicate melts inferences from immiscible liquids abstract the partitioning behavior of rare earth elements ree between immiscible silicate liquids was investigated as a function of temperature and total ree oxide concentration ree preferentially partition into the end member liquids that are rich in network modifying cations with two liquid partition coefficients greater than any other cation the two liquid partition coefficients of ree in a given experiment are essentially identical to one another no evidence was seen to suggest that the solution mechanisms of ree in high silica liquids vary with differences in their ionic radii two lattice models of trace element solution behavior fail to remove the compositional dependence of ree two liquid partition coefficients due to the assumption that all network forming and network modifying cations mix ideally with one another as a result it is probably incorrect to derive physical interpretations from the results of the application of two lattice models the results are applied to the origins of the lree enriched phenocryst matrix partition coefficients seen for some ferromagnesian minerals in high silica rhyolites since liquids with extremely high concentrations of t o t linkages do not strongly discriminate between the ree on the basis of their ionic radii the anomalous ree crystal matrix partition coefficient patterns are best explained as the result of contamination of these minerals by lree accessory phases

spherulitic crystallization in lamprophyric magmas and the origin of ocelli ocelli are rounded structures containing polycrystalline feldspar aggregates and minor amounts of mafic minerals they occur in lamprophyre dykes all over the world ocelli are usually interpreted in terms of liquid immiscibility1 3 in alkaline lamprophyre dykes along the south coast of norway4 ocelli are closely associated with globular structures varioles which i have assumed5 were formed as a result of a splitting of the magma into two fractions the re examination of these norwegian dykes reported here however has shown that varioles ocelli and leucocratic feldspar rich segregations formed by spherulitic and closely related growth mechanisms from under cooled volatile rich magmas without an intervening stage of liquid phase separation

nonmigrating diurnal tides observed in global thermospheric winds 1 nonmigrating diurnal tides between 90 and 270 km are inferred from upper atmosphere research satellite uars wind imaging interferometer windii winds this study represents the first known effort to directly analyze tidal wave number structure and propagation direction in winds observed over this altitude range prominent diurnal tides include an eastward propagating wave number 3 a zonally symmetric tide and a westward propagating wave number 2 uars high resolution doppler imager winds between 60 and 100 km were analyzed identically and show excellent consistency with windii tides observed tides were compared with tidal fits to hough mode extensions windii tides are generally damped more slowly above 120 km than fitted tides and the zonally symmetric tide indicates a thermospheric source not captured by hough mode extensions our study provides additional confirmation that tides act as direct coupling agents between the troposphere and the thermosphere and f region in addition to their role in the e region dynamo

pechenga ferropicrites and other early proterozoic picrites in the eastern part of the baltic shield ti poor komatiites and ti rich picrites exist among the widely occurring primitive mgo rich volcanics in the early proterozoic successions of the kola peninsula both have been encountered in the imandra varzuga belt but only picrites are found in the pechenga complex the picritic rocks are divided into two types the first type restricted to the kolasjoki and pilgujarvi suites and the tominga series is called ferropicrite due to its exceptionally high total iron content which usually exceeds 14 feotot the second type found in the south pechenga series and in the umba and panarechka suites has more typical iron content and geochemically resembles suisaarian picrites from southern karelia ferropicrites occur as pillow lavas lava breccias tuffs massive lavas and up to 50 m thick differentiated spinifex textured flows in addition to high feotot contents these rocks are characterized by low al2o3 contents and by high concentrations of tio2 zr and other incompatible elements they are strongly lree enriched and have immobile trace element characteristics similar to within plate transitional or alkali basalts it is shown that with regard to both the major and trace element compositions the parental magma of the ni bearing intrusions of the pilgujarvi suite is similar to ferropicrite suggesting that the emplacement of the intrusions took place contemporaneously with ferropicritic volcanism the high incompatible element contents of the ferropicritic rocks rule out a genetic relationship with associated tholeiitic basalts proposed geotectonic settings for the pechenga area including an intracratonic rift zone a passive continental margin an oceanic island arc a mature continental volcanic arc and a collisional suture zone are discussed the presence of ti rich picritic rocks does not support a subduction related environment

earth s atmosphere in dynamic coupling envisaged through atmospheric tides and atmospheric gravity waves a view on the past present future research in 1982 1985 an international scientific endeavor was attempted as the middle atmosphere program contributing successfully to exploring the last unknown part of the atmosphere on the planet earth the middle atmosphere now it seems timely for us to consider the whole atmosphere which extends from the ground to the upper atmosphere and further into space as an entity each part of the atmosphere couples not only horizontally globally but also vertically while the horizontal coupling is mainly important for conventional meteorology the vertical one is significant say for space physics and probably future meteorology and will be the present topic atmospheric waves play an important role for the dynamic coupling of the atmosphere transporting energy momentum and material mainly from below and releasing on the way in their propagation upward already in the last century the existence of the tidal dynamo for the geomagnetic sq variation in the upper atmosphere was known as a manifestation of the dynamic coupling by atmospheric tides atmospheric internal gravity waves are now found to play an important role among many others in the general circulation of the middle atmosphere which is another manifestation of the dynamic coupling of the atmosphere reviewing remarkable progress in the last 40 years in the research of this subject the author has suggested that frontiers of the future research would be to develop a gcm general circulation model to include the upper atmosphere and to establish an equatorial atmosphere observation system

on modeling migrating solar tides recent updates and extensions to a steady state two dimensional linearized model of global scale atmospheric waves have facilitated improved calculations of the subset of those waves which are subharmonics of a solar day and propagate with the apparent motion of the sun the model improvements are briefly described and some updated predictions of the migrating solar diurnal component are highlighted the latter represent the first numerical modeling effort to examine the seasonal variability of the migrating diurnal harmonic as it propagates into the mesosphere and lower thermosphere

global mesospheric tidal winds observed by the high resolution doppler imager on board the upper atmosphere research satellite this paper presents preliminary results of a study of mesospheric and lower thermosphedc diurnal tidal winds obtained with the high resolution doppler imager hi on the upper atmosphere research satellite uars zonal averages of the meddional and zonal wind fields are performed at fixed local times these analyses reveal tidal structures in the mean meridional wind field during the months of february and march 1992 results are presented for a typical day in february 1992 the observed maximum amplitude of meridional wind is approximately 75 m s 1 the observed vertical wavelength is about 20 km with amplitudes increasing linearly with height in addition to the tides the zonal wind field reveals many features of the mesospheric

liquid immiscibility in the archean greenstone belt of piumhi minais gerais brazil abstract liquid immiscibility has been used for explaining several modern situations either in effusive or in intrusive rocks liquid immiscibility is also proposed for explaining the variolitic structures in the archean rocks of the abitibi greenstone belt ontario the volcanic sequence of the lower portion of the greenstone belt of piumhi minas gerais brazil shows the occurrence of variolitic structure that may have been formed by liquid immiscibility this possibility is supported by the following points a the contact between varioles and matrix is very sharp b spinifex texture occurs both in the varioles and in the matrix and the single crystal may cross the varioles c the varioles and the matrix show contrasting compositions the latter has the composition of a basaltic komatiite and the former varies form that of an alkali basalt to andesite and d a test by a thermodynamic model from literature shows that although with some doubt the free energy of the possible parent liquid is higher than that of the two unmixed liquids

the meridional wind component of the thermospheric tide observed by windii on uars thermospheric meridional winds measured by the wind imaging interferometer windii on the upper atmosphere research satellite uars are analyzed for migrating solar tides for march april 1993 tidal signatures are extracted by zonally averaging and binning the data in equally spaced intervals of local time latitude and altitude an examination of the binned data reveals vertically propagating tides in the lower thermosphere with the diurnal tide dominating at low latitudes above 120 km evidence of vertical propagation ceases and the vertical gradients are significantly reduced in regions where both daytime and nighttime data are available fourier decomposition of the binned winds is used to extract the diurnal component of the tide this analysis reveals that the propagating diurnal tide attains a maximum amplitude of 65 m s at 20 n and 20 s at 95 km and exhibits a vertical wavelength of about 25 km

simulation of large scale dynamics in the mesosphere and lower thermosphere with the doppler spread parameterization of gravity waves 2 eddy mixing and the diurnal tide turbulence is thought to be produced by gravity waves that become unstable in the upper atmosphere owing to a relatively short vertical wavelength of the solar diurnal tide turbulent viscous type mixing is expected to be particularly important for tidal dissipation in the mesosphere and lower thermosphere mlt within the doppler spread parameterization dsp of gravity waves the vertical eddy exchange coefficients may be calculated from the gw energy deposition rate the dsp as implemented in the spectral mesosphere lower thermosphere model is shown to provide realistic simulations of both the diurnal tide and turbulent mixing in the mlt in particular the vertical structure and seasonal variations of eddy mixing agree well with in situ observations and independent estimates from global thermal balance the seasonal variations of turbulence are found to be primarily responsible for a strong semiannual variation of the diurnal tide in agreement with recent satellite observations

atmospheric tide 2 the solar and lunar semidiurnal components solar and lunar semidiurnal wind and temperature oscillations from the surface to 400 km are simulated for average solar activity conditions utilizing the numerical tidal model described in part 1 hough mode decomposition of the solstitial solar semidiurnal tide excited by h2o and o3 insolation absorption below 80 km indicates that it is characterized by a predominance of 2 2 below 60 km about equal contributions of 2 2 2 3 and 2 4 between 70 and 90 km mostly 2 4 with some 2 5 and 2 2 between 90 and 120 km and a predominance of 2 2 above 140 km with secondary contributions from 2 3 and 2 5 the solstitial lunar semidiurnal tide is characterized by a predominance of 2 2 below 70 km 2 4 with secondary contributions from 2 2 2 3 and 2 5 between 80 and 110 km and by 2 2 with a fairly strong secondary contribution from 2 3 above 120 km similar descriptions for both the solar and lunar oscillations apply at equinox except that the asymmetric 2 3 and 2 5 modes are absent relative to the solar component lunar temperature and wind amplitudes are sufficiently large 20 in the lower and upper thermosphere to account for some of the observed variability previously attributed to the solar tide amplitudes of the 2 4 and 2 5 modes above 100 km are significantly affected by mesospheric eddy diffusion coefficients in excess of 2 106 cm s 1 the total solar semidiurnal exospheric temperature oscillation for average solar conditions ranges from 10 20 k poleward of 40 n to 40 60 k equatorward of 30 n and has its origin in three sources of excitation all of comparable importance 1 euv solar radiation absorption in the lower thermosphere 100 200 km 2 in situ momentum coupling due to the interaction of diurnal winds and diurnally varying ion drag and 3 tides propagating upwards from below 100 km in addition the calculations are compared with rocket meteor radar partial reflection thomson scatter and satellite data to evaluate the consistency of the model with observations

observations of tidal temperature and wind perturbations in the mesopause region above urbana il 40 n 88 w na lidar and mf radar measurements of temperature and horizontal winds were conducted simultaneously during several continuous 24 h periods in march and april 1996 at the urbana atmospheric observatory the data are used to determine the amplitude and phase profiles of the 24 and 12 h tides in the mesopause region between about 82 and 100 km the measured amplitudes and phases of the tidal components of the horizontal winds are generally consistent with the predictions of the global scale wave model gswm the measured 24 h temperature amplitude is comparable to the gswm predictions between 85 and 96 km but is significantly larger than gswm above 96 km the measured phase progression is downward below 94 km with an inferred vertical wavelength of 14 1 km above 94 km the temperature phase progression is upward with a vertical wavelength of 12 1 km the measurements suggest the presence of a diurnal heat source in the lower thermosphere which is generating a strong downwardly propagating 24 h wave

unusual ocellar textures in diabases from the sarmiento ophiolite complex chile unusual ocellar textures from the base of the sheeted dikes unit in the sarmiento ophiolite are described there are significant chemical differences between these ocelli and the surrounding diabasic matrix the mesoscopic textural evidence and the chemical evidence suggest an origin of these ocelli by liquid immiscibility or magma mixing

satellite observations of thermospheric tides results from the wind imaging interferometer on uars thermospheric winds measured by the wind imaging interferometer windii on the upper atmosphere research satellite are analyzed for migrating solar tides the data cover a 2 year period commencing february 1992 and are obtained from the atomic oxygen o 1s 557 7 nm emission which provides observations of the 90 to 200 km altitude range during daytime and the 90 to 110 km range at night the subtropical lower thermosphere is dominated by the diurnal propagating tide which exhibits a vertical wavelength of approximately 22 km grows in amplitude up to 95 km and decays rapidly above where molecular diffusion greatly reduces the vertical shears although the phase remains fairly uniform throughout the year a pronounced semiannual oscillation is observed in the diurnal tide amplitude at both 20 n and 20 s the meridional and zonal wind components attain their maximum values at equinox of approximately 70 and 40 m s respectively while the solstitial minima are nearly a factor of 2 smaller at 35 n the diurnal tide semiannual amplitude oscillation is still present in the lower thermosphere but above 100 km it is replaced by an annual cycle with a maximum in july and august this contrasts with 35 s where the july august peak is absent and the semiannual oscillation extends to 110 km at midlatitudes the zonal and meridional winds are of similar magnitude and no significant hemispheric asymmetries in amplitudes are observed in the lower thermosphere the semidiurnal tide amplitude exhibits an annual oscillation with maximum values of 30 to 40 m s occurring in june july near 100 km at 35 n 35 s and the equator a bimodal structure in the seasonal variation of the semidiurnal phase is observed this feature is characterized by rapid equinoctial transitions and is particularly well defined at the equator examination of the equatorial middle thermosphere indicates that the semidiurnal tide attains its maximum amplitude at 140 km and exhibits a vertical wavelength of approximately 60 km these findings indicate the predominance of the antisymmetric 2 3 hough mode in the tropics

diurnal tide in the equatorial middle atmosphere as seen in lims temperatures abstract the distribution of day night temperature differences in the middle atmosphere determined by the nimbus 7 lims experiment is described day night differences maximize at and are approximately symmetric about the equator successive centers of opposite sign increase in amplitude with altitude the pattern having a vertical wavelength of 25 km profiles of rocket meridional wind at kwajalein 8 7 n and ascension island 8 0 s taken near local noon and averaged over the lims data period exhibit maxima which support the tidal interpretation of the equatorial temperature pattern these characteristics are in general agreement with previous observational and theoretical results for the solar driven diurnal tide substantial time variations in amplitude and in location of the temperature maxima are observed the diurnal tide near the equatorial stratopause appears to be influenced by the phase of the semiannual oscillation

diurnal migrating tide as seen by the high resolution doppler imager uars 1 monthly mean global meridional winds the high resolution doppler imager hrdi instrument on board the upper atmosphere research satellite measures global winds in the mesosphere and lower thermosphere on a day to day basis the horizontal coverage of the hrdi data is excellent and provides a unique opportunity to study global scale dynamic phenomena however the local time resolution and coverage are limited because of the nature of the satellite sampling the lack of local time coverage makes conventional methods of data analysis e g fourier analysis both difficult and erroneous an original method of analysis based on a numerical model of atmospheric thermal tides is proposed and applied to the hrdi data the tidal model is solved for the tidal oscillations in the meridional wind component the simulated diurnal meridional tidal winds are used as a first guess in the analysis the results of the model are adjusted to give meridional migrating tidal winds that have maximum consistency with hrdi measurements this technique is used to derive monthly mean tidal oscillations of the meridional velocity the derived tidal amplitudes show profound seasonal changes that seem to be consistent with gravity wave breaking theory the results are compared with mf radar data it is found that in the upper mesosphere and lower thermosphere the tidal amplitudes obtained by hrdi can be bigger than those from mf radars by a factor of 2

segregation vesicles gas filter pressing and igneous differentiation some vesicles in certain subaerial flows of basalt and basaltic andesite are partially filled with dark partly glassy segregation material the segregation material has about three times the concentration of k o tio and p o as the associated host rock therefore the segregation materials are inferred to be frozen residual liquids that migrated into the vesicles several possible processes for filling the vesicles are examined within the context of the cooling time implied by heat conduction the preferred process is one in which the residual liquid migrates through a porous and permeable but rigid network of interlocking crystals in response to a pressure gradient generated by vapor saturated crystallization as crystallization proceeds h o is concentrated in the residual liquid and gas this produces a higher pressure in the gas poor matrix than in the vesicles and forces liquid to migrate into the vesicles textural features suggestive of or consistent with the process include 1 vesiculation

modeling of the february 1996 peruvian tsunami the february 1996 peruvian earthquake generated a larger tsunami than expected from its surface magnitude this discrepancy as well as the long rupture duration indicate that this event is a tsunami earthquake the associated tsunami was strong locally with runup heights of 1 to 5 meters along a coastline of 400 km it is shown that this tsunami can be modeled for a seismic moment of 2 1020 nm using a rigidity of 2 1010 n m the tsunami propagation is modeled solving long wave equations by a finite difference method the maximum run up heights in the region of chimbote can be simulated using a grid increment of 10 meters the propagation of this small tsunami across the pacific ocean is modeled taking into account frequency dispersion the only notable amplification occurred in the marquesas islands where wave heights of 2 meters were observed and are simulated

global structure and seasonal and interannual variability of the migrating diurnal tide seen in the saber timed temperatures between 20 and 120 km 1 the present paper is focused on the global spatial altitude and latitude structure and seasonal and interannual variability of the migrating diurnal tide derived from the sounding of the atmosphere using broadband emission radiometry thermosphere ionosphere mesosphere energetics and dynamics saber timed temperature measurements for 6 full years january 2002 to december 2007 the tidal results are obtained by a new analysis method where the tides migrating and nonmigrating and the planetary waves zonally traveling and stationary are simultaneously extracted from the satellite data it has been found that above 70 km height the saber migrating diurnal tide reflects mainly the distinctive features of the first symmetric propagating 1 1 mode while below this height it reflects the features of the first symmetric trapped 1 2 mode the trapped component amplifies near 50 km and its phase is close to 1600 lt the seasonal behavior of the diurnal tide over the equator is dominated by semiannual variation with a primary maximum in february march 18 k average amplitude for 6 years and a secondary maximum in august september 15 k the tidal amplitude grows rapidly in the mesosphere lower thermosphere however it undergoes some decay near 90 km defining ubiquitous double peaked vertical structure a very rapid reduction in amplitude is detected at heights near 115 km however above this level the diurnal tide amplifies again the vertical wavelength of the propagating diurnal tide is 20 km over the equator at middle latitudes it is not very different from that over the equator but its magnitude depends on the season in the winter it is longer than that in summer the interannual variability of the diurnal tide indicates a clear correlation with the stratospheric quasi biennial oscillation

ground melting and ocellar komatiites a lead isotopic study at kambalda western australia stratigraphically and geographically restricted ocellar komatiite flows at kambalda western australia appear to represent the products of ground melting of sulphidic sediments by komatiites in lava channels that localized the fe ni cu sulphide ores an immiscible sulphide liquid formed and gravitationally separated from the melted sediment xenomelt the resultant buoyant silicate liquid being partly or wholly assimilated by the turbulently convecting komatiite magma rarely the xenomelt gravitationally migrated to the top of flows and overflowed into the less turbulent lava levees where it collected to form a separate layer overlying a komatiitic layer within a single flow there was selective preservation of the hybrid felsic layer as an upper ocellar unit within an ocellar komatiite flow in lava levees flanking lava channels the ocellar unit is enriched in elements previously concentrated in the sediments and shows u th pb isotopic systematics akin to the underlying sediments moreover the partitioning relationships of u and pb between the immiscible xenomelt and sulphide liquid enhances the range of u pb ratios for components of the ocellar unit thus allowing sufficient spread of modern uranogenic pb isotopic ratios to form isochrons albeit imprecise ones the range and similarity of model th u data from these flows 2 8 3 9 and adjacent sulphidic sediments 2 3 4 4 mostly 2 8 3 9 contrasts with the generally invariable th u within kambalda ultrabasic basic flows 3 6 3 9 and further supports the ground melting hypothesis

liquid immiscibility and melt segregation in alkaline lamprophyres from labrador abstract sannaites alkaline lamprophyres with ti rich mica and or amphibole and k feldspar forming part of the aillik bay alkaline dyke swarm contain two varieties of leucocratic globular structures type i are interpreted to represent immiscible silicate liquids whereas type ii are caused by segregation of late stage melt type i globules are characterised by enrichment in al 2 o 3 sio 2 na 2 o and k 2 o and depletion in cao mgo feo total fe tio 2 and p 2 o 5 relative to the sannaite groundmass mafic minerals inside and outside the type i globules have cores of similar composition but rims which follow different trends type ii globular structures are commonly zoned they have a carbonate analcite inner zone interpreted as the site of a former gas bubble and an outer zone representing late stage liquid minerals in the outer zones show extreme zonation along chemical trends similar to those in the groundmass but contrasting with those in type i globules boundary nucleation is common in type ii but rare in type i the aillik bay sannaites are believed to lie at the alkali alumina rich extremity of the miscibility gap rocks with type ii structures frequently have a two stage groundmass which may be caused by metastable immiscibility compositionally adjacent to the stable miscibility gap

immiscibility synthesis as an indication of cooling rates of basalts abstract silicate liquid immiscibility of iron rich and silica rich compositions have been experimentally reproduced at various cooling rates to evaluate the possible effect of cooling rate on the size of the globules the experiments were performed at constant cooling rates from 1 to 32 c hr under atmospheric pressure and controlled oxygen fugacity a tholeiitic basalt which occurs as a 36 cm thick dike in the izu peninsula japan was used as starting material the sample was melted at the liquidus temperature 1190 5 c and cooled to 1000 c two immiscible liquids occur in the charges as do in the dike in the experiments the size of the globules is strongly related to the cooling rate the diameter of the globules decreases exponentially with increasing cooling rate and the number of globules decreases with decreasing cooling rate these facts together with the typical coalescence shape suggests a growth of globules by coalescence rather than a decrease of the nucleation rate compositional variations of the liquid just prior to splitting within each charge do not affect those of the two immiscible liquids however the compositional differences between the two liquids slightly increase with decreasing cooling rate using the cooling rate vs size relationships the size of globules in basalts allows a cooling rate estimate in the izu dike the 10 largest silica rich globules range from 2 3 m to 0 8 m in the center and the margin suggesting cooling rates of about 15 c hr and greater than 32 c hr respectively at temperatures near 1000 c other estimates from natural samples show a good agreement between deduced cooling rates and observed textures

global distribution and interannual variations of mesospheric and lower thermospheric neutral wind diurnal tide 1 migrating tide 1 using the timed doppler interferometer tidi mesospheric and lower thermospheric neutral wind multiyear data set 2002 2007 and ncar time general circulation models gcm 1 2 annual run results 2002 2005 at the tidi sampling points we study the migrating diurnal tide s global distribution interannual and seasonal variations in connection with the mean zonal wind interannual variations a strong quasi biennial oscillation qbo effect on the diurnal tide was observed in the tidi data and reproduced to a lesser degree in the time gcm run the migrating diurnal tide amplitude is larger during the eastward phase of the stratospheric qbo and weaker during the westward phase westward mesospheric equatorial mean zonal winds appeared during the eastward phase of the stratospheric qbo in 2002 2004 and 2006 the strongest qbo effect on both the migrating diurnal tide and mean zonal winds was observed during the march equinox the stronger tides may be related to the weaker gravity wave filtering in the stratosphere during the eastward phase stratospheric qbo the tidi data also exhibit large interhemispheric asymmetry the westward mean zonal winds in the mesosphere appeared to be associated with the enhanced diurnal tide the time gcm 1 2 diurnal tide amplitudes are in general smaller than those observed by the tidi instrument limited vertical spatial resolution for the time cgm 1 2 is suggested as the cause future improvements are expected with a higher spatial resolution in the model