nonlinear simulations of jupiter s 5 micron hot spots large scale nonlinear simulations of jupiter s 5 micron hot spots produce long lived coherent structures that cause subsidence in local regions explaining the low cloudiness and the dryness measured by the galileo probe inside a hot spot like observed hot spots the simulated coherent structures are equatorially confined have periodic spacing propagate west relative to the flow are generally confined to one hemisphere and have an anticyclonic gyre on their equatorward side the southern edge of the simulated hot spots develops vertical shear of up to 70 meters per second in the eastward wind which can explain the results of the galileo probe doppler wind experiment

mid archaean evolution of the eastern indian craton geochemical and isotopic evidence from the bonai pluton abstract the archaean eastern indian craton consists of several granitoid batholiths intruding greenstone like sequences the bonai pluton one such body in the central sector of the craton consists of a dominant porphyritic and a subordinate equigranular variety ranging in composition from trondhjemite to granite xenoliths of massive trondhjemite migmatite and quartzite occur in both phases the granitoid xenoliths represent remnants of a sialic crust and are the oldest recognizable element in the bonai pluton these are high al 2 o 3 trondhjemites with a highly fractionated rare earth element ree pattern a pb pb isochron age of 3369 57 ma has been obtained from a few spatially related xenoliths the porphyritic and equigranular granitoids show similar petrographic characteristics and most of the samples show a calc alkaline trondhjemitic association a few granite samples however belong to a normal calc alkaline association the trondhjemitic samples are of the low al 2 o 3 type with fractionated light ree lree flat heavy ree hree and a marked negative eu anomaly granites of the calc alkaline association have an identical ree pattern pb isotopic data for all samples together yield a pb pb isochron age of 3163 126 ma the ree characteristics of the two trondhjemite suites can be generated by partial melting of a mafic source with variable residual phases at different depths on the other hand the normal calc alkaline granite may be generated by partial melting of trondhjemite similar in composition to that represented by the 3369 ma xenoliths isotopic ages and the chemical nature of the bonai pluton are similar to those identified in the adjacent singhbhum granite complex it is suggested that the entire eastern indian craton has a common mid archaean history the earliest sialic crust formed at 3400 ma and was followed by trondhjemitic addition at 3300 ma during this phase restricted reworking of the older sialic crust produced calc alkaline granites

residence of ree y th and u in granites and crustal protoliths implications for the chemistry of crustal melts a systematic study with laser ablation icp ms scanning electron microscopy and electron microprobe revealed that 70 95 wt of ree except eu y th and u in granite rocks and crustal protoliths reside within reeythu rich accessories whose nature composition and associations change with the rock aluminosity the accessory assemblage of peraluminous granites migmatites and high grade rocks is composed of monazite xenotime in low ca varieties apatite zircon thorthosilicate uraninite and betafite pyrochlore metaluminous granites have allanite sphene apatite zircon monazite and thorthosilicaie peralkaline granites have aeschinite fergusonite samarskite bastnaesite fluocerite allanite sphene zircon monazite xenotime and th orthosilicate granulite grade garnets are enriched in nd and sm by no less than one order of magnitude with respect to amphibolite grade garnets granulitegrade feldspars are also enriched in lree with respect to amphibolite grade feldspars accessories cause non henrian behaviour of ree y th and u during melt solid partitioning because elevated fractions of monazite xenotime and zircon in common migmatites are included within major minerals their behaviour during anatexis is controlled by that of their host settling curves calculated for a convecting magma show that accessories are too small to settle appreciably being separated from the melt as inclusions within larger minerals biotite has the greatest tendency to include accessories thereby indirectly controlling the geochemistry of ree y th and u we conclude that ree y th and u are unsuitable for petrogenetical modelling of granitoids through equilibrium based trace element fractionation equations

diagenetic origin for quartz pebble conglomerates the occurrence of quartz pebble conglomerates qpc in the rock record increases backward through time from the tertiary through the precambrian the positive correlation between qpc abundance and age is valid both for numbers of reported qpc and for qpc as a percentage of all conglomerate and at both the era and the period level qpc are usually interpreted as being due to intense chemical weathering protracted transport or sediment recycling but none of these can account for the age distribution of qpc which is the opposite of the global mass age distribution for sedimentary rocks precambrian and tertiary conglomerates with similar sources and sedimentology have vastly different clast populations nonquartzose clasts being much more abundant in the younger rocks comparison of the petrology of qpc and polymict conglomerates shows that qpc have consistently higher proportions of diagenetic secondary matrix and pressure solved grain contacts we conclude that diagenetic factors play an important role in qpc formation by preferentially destroying less durable clasts

the galileo probe doppler wind experiment measurement of the deep zonal winds on jupiter during its descent into the upper atmosphere of jupiter the galileo probe transmitted data to the orbiter for 57 5 min accurate measurements of the probe radio frequency driven by an ultrastable oscillator allowed an accurate time history of the probe motions to be reconstructed removal from the probe radio frequency profile of known doppler contributions including the orbiter trajectory the probe descent velocity and the rotation of jupiter left a measurable frequency residual due to jupiter s zonal winds and microdynamical motion of the probe from spin swing under the parachute atmospheric turbulence and aerodynamic buffeting from the assumption of the dominance of the zonal horizontal winds the frequency residuals were inverted and resulted in the first in situ measurements of the vertical profile of jupiter s deep zonal winds a number of error sources with the capability of corrupting the frequency measurements or the interpretation of the frequency residuals were considered using reasonable assumptions and calibrations from prelaunch and in flight testing it is found that beneath the cloud tops about 700 mbar the winds are prograde and rise rapidly to 170 m s at 4 bars beyond 4 bars to the depth at which the link with the probe was lost nearly 21 bars the winds remain constant and strong corrections for the high temperatures encountered by the probe have recently been completed and provide no evidence of diminishing or strengthening of the zonal wind profile in the deeper regions explored by the galileo probe

motions in jovian hot spot plume regions using voyager images abstract we have measured the motions and wind velocity vectors in six jovian hot spot plume areas latitudes 0 to 12 using high resolution voyager 1 and 2 images separated by one jovian rotation 10 hr rapid changes in cloud forms take place in a few hours at scales from 100 to 2000 km no large scale organized motions e g diagonal convergence along the plume tails toward hot spots or circulation patterns such as those recently reported using galileo images separated by 1 hr have been found we show that particle evaporation and cloud element mixing in the upper ammonia cloud could be fast enough to dissipate the small cloud elements such as those used as tracers by the galileo ssi team in less than 10 hr

dating the oldest terrestrial rocks fact and fiction abstract this paper is a review of well documented geochronological and related isotopic evidence for the age and total crustal residence time of the oldest known terrestrial rocks mainly using rb 1bsr sm 1bnd and u 1bpb decay schemes the oldest known stable sialic crust of true continental character predominantly composed of calc alkaline orthogneisses was produced during major mantle differentiation some 3 7 3 5 ga ago and is represented on several continents enclaves of older supracrustal rocks as well as a major remnant of a volcano sedimentary sequence of greenstone belt affinity dated at 3 8 ga are preserved within the surrounding gneisses in southern west greenland recent ionmicroprobe evidence for 4 1 ga old detrital zircon grains in a younger early archaean metasedimentary sequence in western australia is also discussed several cases are reviewed where claims for early archaean 3 4 ga dates are believed to be erroneous and to result from oversimplistic and incorrect interpretation of isotopic data some of the geological and geochemical mechanisms which have given rise to claims for spuriously old sm 1bnd u 1bpb and pb pb dates are critically discussed to supplement published data we present several new sets of whole rock sm 1bnd and pb pb isotopic data from west greenland labrador zimbabwe and eastern india relevant to the overall topic of this review

sr and nd isotopes in river sediments from the ganga basin sediment provenance and spatial variability in physical erosion 1 sr and nd concentrations and isotope compositions in sediment of the ganga river from gangotri to rajmahal and its tributaries have been measured to determine provenance and the spatial variability in physical erosion among the ganga subbasins sr and nd in silicates range from 37 to 138 and from 10 to 36 g g with 87sr 86sr and nd of 0 7474 0 8428 and 25 5 to 15 5 respectively the results suggest that 65 of ganga mainstream sediments are derived from the higher himalayan crystallines highlighting intense physical erosion in this region the 87sr 86sr values of sediments in the gangetic plain show nearly identical trends during two seasons with a sharp and significant decrease at barauni downstream of gandak confluence this brings out the major impact of the sediment contribution from the gandak to the ganga mainstream model calculation suggests that about half of the ganga sediment at rajmahal is sourced from the gandak the erosion rates in the himalayan subbasins of the ganga range between 0 5 and 6 mm a where a is years with the gandak having the highest erosion rate high relief and intense precipitation over the headwater basins of the gandak appear to drive the rapid and focused erosion of this basin the results of this study and those in literature suggest that the eastern syntaxis brahmaputra the western syntaxis indus and the gandak have much higher physical erosion rates than the other himalayan basins focused erosion in the hot spots of these river basins contributes significantly to the global riverine sediment budget and influence regional tectonics

sm nd isotopic and geochemical study of the archean tonalite amphibolite association from the eastern indian craton we report the results of a sm nd isotopic major element and rare earth element ree study of the older metamorphic group omg tonalite amphibolite association of the eastern indian craton the older metamorphic tonalite gneisses omtg have been previously dated to be 3 8 ga using sm nd isotope systematies and 3 2 3 4 ga by rb sr and pb pb dating the results of this study indicate that the protoliths of the omg amphibolites are 3 3 ga isochron age 3 30 0 06 ga nd 0 9 0 7 and therefore the omtg which intrude into the associated amphibolites cannot be any older than 3 3 ga the amphibolites display light ree enrichment ce yb n 2 2 6 7 la 30 100 x chondrite and nearly flat heavy ree patterns tb lu n 1 2 1 9 the basaltic parents of the amphibolites were probably generated by the partial melting of a spinel lherzolite mantle strong linear relationships between the amphibolites and tonalites in 147sm 144nd 143nd 144nd space isochron age 3 29 0 04 ga nd 0 8 0 8 imply that they are genetically related the tonalites display fractionated ree patterns la 100 300 x chondrite with moderate heavy ree depletions tb lu n 1 9 3 4 the isotopic major element and ree data are consistent with the derivation of the omtg from partial melting of omg amphibolites or equivalent rocks at amphibolegarnet stabilization depths an initial nd t value of 0 9 0 7 for the amphibolites indicates the presence of a slightly depleted mantle source at 3 3 ga with 147sm 144nd between 0 20 and 0 22 it is suggested that the growth of continental crust in the eastern indian craton occurred in response to magmatic underplating in a plume setting

computer simulations of jupiter s deep internal dynamics help interpret what juno sees we describe computer simulations of thermal convection and magnetic field generation in jupiter s deep interior that is its convective dynamo results from three different simulations highlight the importance of including the dynamics in the very deep interior although much of the convection and field generation seems to be confined to the upper part of the interior a long debated question is to what depth do jupiter s zonal winds extend below its surface our simulations suggest that if global latitudinally banded patterns in jupiter s near surface magnetic and gravity fields were detected by juno nasa s orbiting spacecraft at jupiter bolton s et al 2017 science 356 821 825 they would provide evidence for jupiter s zonal winds extending deep below the surface one of our simulations has also maintained for a couple simulated years a deep axisymmetric inertial wave with properties at the surface that depend on the size of the model s small rocky core if such a wave was detected on jupiter s surface its latitudes and oscillation frequency would provide evidence for the existence and size of jupiter s rocky core

jupiter s main auroral oval observed with hst stis 1 an extended series of fuv images obtained on 7 days during winter 2000 2001 with fixed pointing yielded highly accurate tracking of emisson features as jupiter rotated they provided newly detailed measurements of the degree of corotation of auroral emissions and their variations with changing central meridian longitude this 2 month data set provides a statistical average location of the auroral emission and leads to the definition of new reference ovals the overall auroral morphology pattern is shown to be fixed in system iii longitude and unchanged over a 5 year period when arranged in central meridian longitude ranges the images show a significant contraction of the northern main oval as the central meridian longitude increases from 115 to 255 the main auroral oval brightness is globally very stable in comparison with its terrestrial counterpart it is shown to vary with magnetic local time increasing from noon to dusk and then decreasing again in the magnetic evening hectometric emissions observed simultaneously with galileo and cassini reveal interplanetary shocks propagating outward from the sun which may be related to the contraction of the main auroral oval observed in the hst images taken on 14 december 2000 in addition we find that a brightening and a significant contraction of the main oval observed on 13 january 2001 corresponded to a time of increased solar wind dynamic pressure

mesoscale and submesoscale processes in the southeast atlantic and their impact on the regional thermohaline structure the turbulent processes in the cape basin the southeasternmost gate of the atlantic ocean play a key role in the transport and mixing of upper to intermediate water masses entering the area from the indian ocean making them especially relevant for the indo atlantic transfer of heat and salt in this paper two numerical simulations at different horizontal resolutions are used to study meso and submesoscale dynamics their phenomenology their evolution and their impact on the local water masses submesoscale processes seasonally affect both the upper and intermediate layers but there are clear dynamical differences between the two layers several types of instabilities underline this spatial and temporal variability near the surface mixed layer instabilities occur during winter while mesoscale driven instabilities as the symmetric type prevail in summer the connection between these two seasonal regimes is ensured in anticyclonic eddies and within the mixed layers by charney baroclinic instabilities involved in the local formation and subduction of mode water that we have dubbed as agulhas rings mode water intermediate depths are instead characterized by mesoscale mechanisms of density compensation and lateral stirring of the tracer variance triggering a significant filamentogenesis whose vertical scales are comparable to those mentioned in previous studies this leads to a particularly efficient mixing of antarctic intermediate waters of indian and atlantic origins lagrangian estimates highlight the new and significant role of fine scale structures in setting the water masses properties of upper and lower thermocline waters materializing the indo atlantic exchange and therefore potentially affecting the global ocean circulation

geochemistry of archean shales from the pilbara supergroup western australia archean clastic sedimentary rocks are well exposed in the pilbara block of western australia shales from turbidites in the gorge creek group ca 3 4 ae and shales from the whim creek group ca 2 7 ae have been examined the gorge creek group samples characterized by muscovite quartzchlorite mineralogy are enriched in incompatible elements k th u lree by factors of about two when compared to younger archean shales from the yilgarn block alkali and alkaline earth elements are depleted in a systematic fashion according to size when compared with an estimate of archean upper crust abundances this depletion is less notable in the whim creek group such a pattern indicates the source of these rocks underwent a rather severe episode of weathering the gorge creek group also has fairly high b content 85 29 ppm which may indicate normal marine conditions during deposition rare earth element ree patterns for the pilbara samples are characterized by light ree enrichment lanybn 7 5 and no or very slight eu depletion eueu 0 82 0 99 a source comprised of about 80 felsic igneous rocks without large negative eu anomalies felsic volcanics tonalites trondhjemites and 20 mafic ultramafic volcanics is indicated by the trace element data very high abundances of cr and ni cannot be explained by any reasonable provenance model and a secondary enrichment process is called for

emplacement of clay into sand by infiltration abstract laboratory experiments and examination of core samples from holocene sand bodies demonstrate that vadose infiltration of muddy water through sand is an effective mechanism by which clay can be emplaced into sand infiltrated clays form coatings on and bridges between sand sized framework grains clay particles are mostly oriented parallel to grain surfaces in coatings and perpendicular to grain surfaces in bridges the amount of clay emplaced as coatings and bridges is determined by complexly interacting variables that include sand grain size clay particle size clay particle shape concentration of suspended sediment and clay composition of these relatively coarse sand sizes and high concentrations of suspended sediment appear to promote the emplacement of the most infiltrated clay in holocene sands the formation of grain coatings and bridges is facies dependent infiltrated clays are most effectively emplaced in environments characterized by high suspended sediment concentrations fluctuating water levels and minimal sediment reworking e g point bar and delta plain in contrast virtually no infiltrated clay is emplaced in environments characterized by low suspended sediment concentration and continuous reworking e g beach and tidal delta

sheared bedding parallel quartz vein as an indicator of deformation processes abstract monomineralic veins are well known as good recording of filling and precipitation processes however they are also able to register the action of deformation in rocks we used monomineralic quartz veins from quadrilaterro ferrifero brazil to represent how the deformation actuated during the transformation of different structures they were analyzed using a combination of a u stage and ebsd two main types of quartz aggregates are distinguished single crystals with subgrain development and strain free grains of quartz we interpret the microstructures and textures as the result of a combination of concurrent crystal plasticity microfracturing solution transfer and recrystallization the single quartz grains were deformed by dislocation glide however as the c axis orientation of the grain was not favorable for further glide on basal planes the deformation was accommodated by microfracturing new grains were formed along the deformed zones with crystallographic orientations suitable for gliding on basal planes as the deformation proceeded the new grains continue to develop until the vein was completely recrystallized into an aggregate of granular grains

the 10 october 1999 hip 9369 occultation by the northern polar region of jupiter ingress and egress lightcurves analysis abstract the occultation of bright star hip9369 by the northern polar region of jupiter was observed from four locations in north and south america providing four data sets for ingress and egress the inversion of the eight occultation lightcurves provides temperature profiles at different latitudes ranging from 55 n to 73 2 n we estimate the errors on the profiles due to the uncertainties of the inversion method and compare the value of the temperature at the deepest level probed 50 bar with previous observations the shape of the temperature gradient profile is found similar to previous investigations of planetary atmospheres with propagating and breaking gravity waves we analyze the small scale structures in both lightcurves and temperature profiles using the continuous wavelet transform the calculated power spectra of localized fluctuations in the temperature profiles show slopes close to 3 for all eight profiles we also isolate and reconstruct the three dimensional geometry of a single wave mode with vertical and horizontal wavelengths of respectively 3 and 70 km the identified wave is consistent with the gravity wave regime with a horizontal phase speed nearly parallel to the planetary meridian nevertheless the dissipation of the corresponding wave in jupiter s stratosphere should preclude its detection at the observed levels and an acoustic wave cannot be ruled out

geochemistry of banded iron formation of orissa india major and trace element analyses of representative samples of various types of banded iron formation and its various minerals associated sediments iron ores and volcanic tuff from different localities of orissa india are presented in this paper the orissa banded iron formation is classified as precambrian banded iron formation and is similar to the oxide facies iron formation of lake superior type the orissa iron formation consists only of iron oxide and silica with total absence of iron silicate sulfide and carbonate minerals and is devoid of terrigenous material the trace element content suggests the source of the underlying quartzite to be a continental igneous rock mass while the interbedded tuff are of undoubted volcanic origin the overlying iron formation were chemically precipitated as oxidate sediments in which the principal iron mineral magnetite was formed at low temperature in a shallow marine environment from the overwhelming similarity of major and trace element contents of all the samples from the different localities it is postulated that these detached outcrops originated in the same continous basin

sedimentary rocks and crustal evolution tectonic setting and secular trends a significant change in the composition of turbidites deposited at active tectonic settings is seen at the archean post archean transition in comparison to post archean active margin turbidites archean greenstone turbidites exhibit more uniform th sc ratios but with a similar average greater hree depletion gd n yb n 2 less eu depletion eu eu mostly 0 85 and an absence of low th u ratios th u 3 these data indicate that differing mantle sources and or conditions of mantle melting existed during the archean and that intracrustally differentiated rocks older cratons or young differentiated arcs were relatively unimportant as provenance components for archean turbidites in contrast some sedimentary rocks preserved in archean platformal sequences of high grade terranes display significant negative eu anomalies similar to the majority of post archean shales indicating that the general process of cratonization including intracrustal differentiation has taken place since at least 3

jupiter s interior and deep atmosphere the initial pole to pole passes with the juno spacecraft on 27 august 2016 the juno spacecraft acquired science observations of jupiter passing less than 5000 kilometers above the equatorial cloud tops images of jupiter s poles show a chaotic scene unlike saturn s poles microwave sounding reveals weather features at pressures deeper than 100 bars dominated by an ammonia rich narrow low latitude plume resembling a deeper wider version of earth s hadley cell near infrared mapping reveals the relative humidity within prominent downwelling regions juno s measured gravity field differs substantially from the last available estimate and is one order of magnitude more precise this has implications for the distribution of heavy elements in the interior including the existence and mass of jupiter s core the observed magnetic field exhibits smaller spatial variations than expected indicative of a rich harmonic content

archean banded iron formations of india abstract archean banded iron formations bifs are important lithologies for understanding the early earth processes greenstone belts in the four archean cratonic nucleii of peninsular india namely singhbhum bastar dharwar and bundelkhand host bif units that can be important candidates for case studies the bifs in these greenstone successions represent both algoma and superior type associations the oldest record comes from the paleoarchean southern eastern and western iron group of the singhbhum craton and the sargur supracrustals of the dharwar craton mesoarchean and neoarchean greenstone belts in the dharwar and bundelkhand cratons record a number of cycles of bif deposition in a spectrum of depositional settings from manganiferous arenite carbonate shelf associations to deep water volcanics and graywacke associations the bifs from the neoarchean bailadila group in the bastar craton were deposited in siliciclastic shelf association compositional variations in major trace and ree patterns have been evaluated from published data high grade iron ores are mainly mined from the bifs and locally mn ores occur in association as well microbial carbonates associated with some of the paleoarchean as well as neoarchean iron manganese formations suggest early life activities the lithological association of the archean iron formations have been explained in terms of both active margin and passive margin depositional settings bifs in association with manganiferous formations as old as paleoarchean time provide an opportunity to probe into the redox stratification of oceanic hydrosphere and in turn the oxygenation of early atmosphere

saturn s equinoctial auroras received 23 october 2009 accepted 24 november 2009 published 23 december 2009 1 we present the first images of saturn s conjugate equinoctial auroras obtained in early 2009 using the hubble space telescope we show that the radius of the northern auroral oval is 1 5 smaller than the southern indicating that saturn s polar ionospheric magnetic field measured for the first time in the ionosphere is 17 larger in the north than the south despite this the total emitted uv power is on average 17 larger in the north than the south suggesting that field aligned currents facs are responsible for the emission finally we show that individual auroral features can exhibit distinct hemispheric asymmetries these observations will provide important context for cassini observations as saturn moves from southern to northern summer citation nichols j d et al 2009 saturn s equinoctial auroras geophys res lett 36 l24102 doi 10 1029 2009gl041491

alumina rich rocks from the early precambrian of the kaapvaal craton as indicators of paleosols and as products of other decompositional reactions within early archaean to early proterozoic pelites and volcanics of the kaapvaal craton rocks with above 20 al2o3 are widely distributed the alumina rich nature of these rocks is ascribed to decompositional reactions during which up to about 60 of the original material was leached out of the source rock and removed in solution many of these rocks also show diagenetic enrichment in k2o of up to 10 the decomposition reactions in many cases affected the source rocks without disturbing fine structures such as perlitic devitrification cracks in volcanic glass granules the origin of the majority of these rocks can be ascribed to decomposition during subaerial weathering they represent paleosols for other occurrences the stratigraphic context rules out an explanation as paleosols the origin of this type is ascribed to subaqueous decomposition of lavas or tuffs assisted by hydrothermal exhalations it is shown that alumina rich rocks in greenschist belts almost exclusively formed subaqueously whereas the younger occurrences mostly are of weathering origin geotectonic differences are invoked to explain this contrast rocks of similar chemical composition are described from the canadian shield zimbabwe western australia india and the baltic shield they illustrate that the preservation potential of these rocks is high only the study of the stratigraphic context will allow a conclusion on whether a particular occurrence is the product of weathering or subaqueous decomposition

first measurements of jupiter s zonal winds with visible imaging spectroscopy abstract we present the first measurements of jupiter s wind profile ever obtained with doppler velocity measurements in the visible hitherto knowledge about atmospheric dynamics has been obtained with cloud tracking techniques which consist of tracking visible features from images taken at different dates however cloud tracking indicates the motion of large cloud structures which is an indication of the speed of iso pressure regions rather than the speed of the actual atmospheric particles doppler imaging is as challenging motions are usually less than 100 m s 1 as appealing because it measures the speed of cloud particles instead of large cloud structures significant difference could appear in the case of atmospheric waves interfering with cloud structures here we present the first scientific results of a doppler imaging spectrometer that is dedicated to giant planet seismology and atmospheric dynamics by providing instantaneous line of sight velocity maps of the planets of the solar system the instrument has been developed in the framework of the projects jovial jovian oscillations through velocity images at several longitudes and jive in nm jovian interiors from velocimetry experiment in new mexico it is a fourier transform spectrometer with a fixed optical path difference working in the mid visible domain which monitors the position of solar fraunhofer lines that are reflected in the planets upper atmospheres after describing the instrument principle and the different steps of data reduction we report measurement of the average zonal wind speed of jupiter as a function of latitude from datasets obtained in 2015 and 2016 with two different telescopes when the planet was close to its opposition our results are consistent between the two years we compare the results with wind profiles obtained by cloud tracking on hst hubble space telescope images taken at the same epoch and identify a significant discrepancy in the north equatorial belt and northern part of the equatorial zone

207pb 206pb zircon ages and the evolution of the singhbhum craton eastern india an ion microprobe study1this paper is dedicated to prof a k saha one of the senior co authors who passed away after submission of the paper 1 abstract we used an ion microprobe to measure 207 pb 206 pb ages of single zircons from four key lithologies from the singhbhum craton of eastern india detrital zircons from the oldest recognized sedimentary sequence of the craton the older metamorphic group yielded 3 5 3 6 ga ages indicating that crustal formation had already been initiated by 3 6 ga in this region this data also established an older limit of 3 5 ga for the age of sediment deposition the first appearance of extensive continental crust in the singhbhum region marked by the emplacement of the older metamorphic tonalite gneisses is dated at 3 44 ga our data from both of these units reveal that a 3 2 ga event induced overgrowths within each of these pre existing zircon populations we determine an age of 3328 7 ma for the singhbhum granite phase ii the most widespread of this granite s three phases the emplacement of the two phases of the mayurbhanj granite marking the youngest major episode of acid plutonism in this craton took place in rapid succession at 3 1 ga marking the broad scale stabilization of this terrain

agulhas ring formation as a barotropic instability of the retroflection 1 agulhas leakage is an important link in the global ocean circulation as it transfers a significant volume of relatively warm and salty water from the indian ocean to the atlantic ocean the main route of this transfer is through the shedding of large agulhas rings from the agulhas retroflection in this paper we study the dynamics of the ring formation process by analyzing the stability of the indian atlantic supergyre in a reduced gravity model we show that the ring shedding process results from a barotropic instability of the steady circulation in the agulhas retroflection region the destabilizing mode appears to be linked to a rossby basin mode of the combined south indian atlantic basin which is localized in the retroflection region by the background flow

a study of the stability of jovian zonal winds from hst images 1995 2000 abstract we present a five year study of the temporal stability of jupiter s zonal wind velocity profile at cloud level based on hubble space telescope images obtained from 1995 to 2000 we used the correlation of east west albedo scans in pairs of images separated by one jovian rotation to retrieve the zonal winds the resolution in the hst images ranged from 140 to 190 km pixel 1 independent measurements of the motions of individual cloud tracers were used to control the above profiles three wavelengths were used in this analysis 410 nm violet continuum 892 nm methane absorption band and 953 nm red continuum our study indicates that globally jupiter s zonal flow did not change during this five year interval and it does not depend on the observed wavelengths when comparing our mean profile with that obtained 16 years ago using voyager data we find a reasonable agreement we note however a small shift in the latitude of the jets poleward of latitude 30 probably due to image navigation uncertainties however true changes in the intensity of the jets at 24 n and 32 n are found results also indicate that the 7 s jet has remained stable since the voyager era in addition we extend in this paper our previous study of the 24 n with new data from year 2000 the new data confirm the jet s stability during the 1995 2000 period finally we present the average profile for this period including error estimation in a table that extends the latitudinal coverage of limaye s 1986 icarus 65 335 352 voyager profile up to latitudes 68 s and 77 n

prevalent lightning sferics at 600 megahertz near jupiter s poles lightning has been detected on jupiter by all visiting spacecraft through night side optical imaging and whistler lightning generated radio waves signatures1 6 jovian lightning is thought to be generated in the mixed phase liquid ice region of convective water clouds through a charge separation process between condensed liquid water and water ice particles similar to that of terrestrial cloud to cloud lightning7 9 unlike terrestrial lightning which emits broadly over the radio spectrum up to gigahertz frequencies10 11 lightning on jupiter has been detected only at kilohertz frequencies despite a search for signals in the megahertz range 12 strong ionospheric attenuation or a lightning discharge much slower than that on earth have been suggested as possible explanations for this discrepancy13 14 here we report observations of jovian lightning sferics broadband electromagnetic impulses at 600 megahertz from the microwave radiometer 15 onboard the juno spacecraft these detections imply that jovian lightning discharges are not distinct from terrestrial lightning as previously thought in the first eight orbits of juno we detected 377 lightning sferics from pole to pole we found lightning to be prevalent in the polar regions absent near the equator and most frequent in the northern hemisphere at latitudes higher than 40 degrees north because the distribution of lightning is a proxy for moist convective activity which is thought to be an important source of outward energy transport from the interior of the planet16 17 increased convection towards the poles could indicate an outward internal heat flux that is preferentially weighted towards the poles9 16 18 the distribution of moist convection is important for understanding the composition general circulation and energy transport on jupiter observations of broadband emission from lightning on jupiter at 600 megahertz show a lightning discharge mechanism similar to that of terrestrial lightning and indicate increased moist convection near jupiter s poles

heat production heterogeneity of the indian crust beneath the himalaya insights from the northern indian shield abstract crustal thermal structure of the himalaya depends partly on the thermal properties of the indian crust that has subducted beneath the himalayan range and partly accreted to it in most studies the indian crust is assigned uniform thermal properties mostly derived from the data from southern india we show here that this might actually not be a good assumption based on the in situ heat production measurements at 279 sites in the bundelkhand craton chottanagpur gneissic complex and singhbhum craton the dominant rocks granites and gneisses in the bundelkhand craton and chottanagpur gneissic complex are characterized by high heat production 3 93 6 52 w m 3 whereas the rocks in the singhbhum craton are low in heat production 1 41 3 27 w m 3 thereby suggesting a large variation of heat production in the northern indian shield the available surface heat flow values also show consistently large variation from 56 to 96 mw m 2 the crustal heat production heterogeneity within the indian crust has to be duly considered in the interpretation of thermobarometric and thermochronological data of the himalaya

h3 as an ionospheric sounder of jupiter and giant planets an observational perspective thirty years of observations of h3 on jupiter have addressed many complex questions about the physics of the ionospheres of the giant planets spectroscopy imaging and imaging spectroscopy in the

rare earth elements in the indian banded iron formation abstract the normalised patterns of rare earth elements ree of the banded iron formation bif associated rocks and ores from eastern india show similarities to the patterns of the bif from other parts of the world but their absolute content is rather low for the chemically precipitated rocks of india the process of formation appears to have influenced the relative concentration as the clastic phases are richer in ree compared to the chemically precipitated rocks the observed ce and eu anomalies are similar to those reported for such rocks and have been ascribed to mineralogy and process of formation rather than to their temporal position or the source rock the bif of precambrian and younger age could very well be discriminated by the eu sm ratio the ree are selectively enriched in the fe oxides compared to silica during diagenetic differentiation but neither diagenesis nor metamorphism affects the distribution patterns of the ree as diagenetically unaffected supergene products and highly metamorphosed bif exhibit analogous normalised patterns

jupiter s equatorial plumes and hot spots spectral mapping from gemini texes and juno mwr we present multi wavelength measurements of the thermal chemical and cloud contrasts associated with the visibly dark formations also known as 5 m hot spots and intervening bright plumes on the boundary between jupiter s equatorial zone ez and north equatorial belt neb observations made by the texes 5 20 m spectrometer at the gemini north telescope in march 2017 reveal the upper tropospheric properties of 12 hot spots which are directly compared to measurements by juno using the microwave radiometer mwr jiram at 5 m and juno cam visible images mwr and thermal infrared spectroscopic results are consistent near 0 7 bar mid infrared derived aerosol opacity is consistent with that inferred from visible albedo and 5 m opacity maps aerosol contrasts the defining characteristics of the cloudy plumes and aerosol depleted hot spots are not a good proxy for microwave brightness the hot spots are neither uniformly warmer nor ammonia depleted compared to their surroundings at p 10 bars suggesting that the hot spot plume wave is a relatively shallow feature plain language summary to date our only direct measurement of jupiter s gaseous composition came from the descent of the galileo probe in 1995 however the results from galileo appeared to be biased due to the unusual meteorological conditions of its entry location a dark cloud free region just north of the equator known as a hot spot one of the aims of nasa s juno mission was to place the findings of the galileo probe into broader con text which requires a detailed characterisation of these equatorial hot spots and their neighbouring plumes we combine a data from juno microwave observations sounding conditions below the clouds and visible infrared observations revealing variations in cloud opacity with b observations from amateur observers to track the hot spots over time and c observations from the texes infrared spectrometer mounted on the gemini north telescope the latter provides the highest resolution thermal maps of jupiter s tropics ever obtained and reveals contrasts within and between the individual hot spots and plumes we find that the hot spots are distinguishable from their surroundings for relatively shallow pressures but that the deep measurements from juno and galileo are probably more representative of jupiter s north equatorial belt than previously thought

meteorology of jupiter s equatorial hot spots and plumes from cassini we present an updated analysis of jupiter s equatorial meteorology from cassini observations for two months preceding the spacecraft s closest approach the imaging science subsystem iss onboard regularly imaged the atmosphere we created time lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes hot spots are relatively cloud free regions that emit strongly at 5 lm improved knowledge of these features is crucial for fully understanding galileo probe measurements taken during its descent through one hot spots are quasistable rectangular dark areas on visible wavelength images with defined eastern edges that sharply contrast with surrounding clouds but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes hot spots exhibit significant variations in size and shape over timescales of days and weeks some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots impressive bright white plumes occupy spaces in between hot spots compact cirrus like scooter clouds flow rapidly through the plumes before disappearing within the dark areas these clouds travel at 150 200 m s 1 much faster than the 100 m s 1 hot spot and plume drift speed this raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip if a downward branch of an equatorially trapped rossby wave controls the overall appearance of hot spots however the westward phase velocity of the wave leads to underestimates of the true jet stream speed

jupiter s visible aurora and io footprint images obtained by the galileo spacecraft s solid state imaging ssi system represent the first survey of jupiter s northern auroral emissions at visible wavelengths and on the nightside of the planet these images captured the emissions with unprecedented spatial resolutions down to 26 km pixel 1 four classes of emission were observed 1 a continuous primary arc associated with the middle outer magnetosphere 2 a variable secondary arc associated with the region just beyond io s torus 3 diffuse polar cap emission and 4 a patch and tail associated with the magnetic footprint of io the primary arc emission occurs at an altitude 245 30 km above the 1 bar pressure level its horizontal width is typically a few hundred kilometers and its total optical power output varied between 10 10 and 10 11 w in observations taken months apart the location of the primary arc in planetary coordinates is similar to that on dayside images at other wavelengths and does not vary with local time the morphology of the primary arc is not constant changing from a multiply branched latitudinally distributed pattern after dusk to a single narrow arc before dawn emission from io s ionospheric footprint is distinct from both the primary and secondary arcs measurements of its optical power output ranged from 2 to 7 10 8 w

why is the h3 hot spot above jupiter s great red spot so hot recent observations of jupiter s great red spot indicate that the thermosphere above the storm is hotter than its surroundings by more than 700 k possible suggested sources for this heating have t

dynamics of saturn s polar regions we analyze data retrieved by the imaging science system onboard the cassini spacecraft to study the horizontal velocity and vorticity fields of saturn s polar regions latitudes 60 90 n in june december 2013 and 60 90 s in october 2006 and july december 2008 including the northern region where the hexagonal wave is prominent with the aid of an automated two dimensional correlation algorithm we determine two dimensional maps of zonal and meridional winds and deduce vorticity maps we extract zonal averages of zonal winds providing wind profiles that reach latitudes as high as 89 5 in the south and 89 9 in the north wind measurements cover the intense polar cyclonic vortices that reach similar peak velocities of 150 m s 1 at 88 5 the hexagonal wave lies in the core of an intense eastward jet at planetocentric latitude 75 8 n with motions that become nonzonal at the hexagonal feature in the south hemisphere the peak of the eastward jet is located at planetocentric latitude 70 4 s a large anticyclone the south polar spot sps similar to the north polar spot nps observed at the voyager times 1980 1981 has been observed in images from april 2008 to january 2009 in the south polar region at latitude 66 1 close to the eastward jet the sps does not apparently excite a wave on the jet we analyze the stability of the zonal jets finding potential instabilities at the flanks of the eastward jets around 70 and we measure the eddy wind components suggesting momentum transfer from eddy motion to the westward jets closer to the poles

jupiter s atmospheric jet streams extend thousands of kilometres deep the depth to which jupiter s observed east west jet streams extend has been a long standing question resolving this puzzle has been a primary goal for the juno spacecraft which has been in orbit around the gas giant since july 2016 juno s gravitational measurements have revealed that jupiter s gravitational field is north south asymmetric which is a signature of the planet s atmospheric and interior flows here we report that the measured odd gravitational harmonics j 3 j 5 j 7 and j 9 indicate that the observed jet streams as they appear at the cloud level extend down to depths of thousands of kilometres beneath the cloud level probably to the region of magnetic dissipation at a depth of about 3 000 kilometres by inverting the measured gravity values into a wind field we calculate the most likely vertical profile of the deep atmospheric and interior flow and the latitudinal dependence of its depth furthermore the even gravity harmonics j 8 and j 10 resulting from this flow profile also match the measurements when taking into account the contribution of the interior structure these results indicate that the mass of the dynamical atmosphere is about one per cent of jupiter s total mass

mesospheric temperature inversion and gravity wave breaking more than 500 nightly mean temperature profiles have been obtained since 1981 by two rayleigh lidars located in south of france 550 km apart in the mesosphere a temperature inversion a feature persisting for several days is frequently observed simultaneously at both sites from a statistical study of the inversion characteristics it is shown that its altitude ranges from 55 72 km in winter to 70 83 km in summer while its probability of occurrence presents a semi annual variation with a maximum higher in winter than in summer and a minimum lower in may than in september the seasonal variation of the temperature inversion is shown to be very similar to that of the mst radar echoes in the mesosphere associated to turbulent layers generated by the breaking of gravity waves a crude estimate of the amplitude growth with height of a gravity wave in the presence of an inversion layer indicates that the wave will break preferably inside and above this layer the persistence of a temperature inversion during several days with amplitude as large as 40 k is tentatively explained by the heating of the turbulent layers generated by the continuous breaking of gravity waves above the secondary minimum of temperature

growth of granite greenstone terranes at convergent margins and stabilization of archean cratons abstract archean granite greenstone terranes represent juvenile continental crust formed in a variety of plate tectonic settings and metamorphosed through a complex series of structural and magmatic events most archean granite greenstone terranes appear to have acquired their first order structural and metamorphic characteristics at convergent plate margins where large accretionary wedges similar in aspect to the chugach makran and altaids grew through offscraping and accretion of oceanic plateaux oceanic crustal fragments juvenile island arcs rifted continental margins and pelagic and terrigenous sediments buoyant slabs of parts of archean oceanic lithosphere may have been underplated beneath these orogens forming thick crustal roots characterized by interleaving between the depleted slabs and undepleted asthenosphere back stepping of the subduction zones after accretion of plateaux and arcs caused the arcs magmatic fronts to migrate trenchward through the accretionary wedges dehydration of the subducting slabs hydrated the mantle wedges below the new arcs and generated magmas sanukitoid suite in the mantle wedge whereas other magmas tonalite trondhjemite granodiorite or ttg suite appear to have been generated by melting of hot young subducted slabs eventual collision of these juvenile orogens with other continental blocks formed anatectic granites then thickened the crust beyond its ability to support its own mass which initiated gravitational collapse and decompressional release of syn to late tectonic granitoids from wedges of fertile mantle trapped between underplated oceanic lithospheric slabs and aided in the cratonization of the granite greenstone terranes deeply penetrating structural discontinuities such as shear zones and sutures provided pathways for fluids and granitoids to migrate into the mid and upper crust forming ore deposits and plutons most preserved granite greenstone terranes have been tectonically stable since the archean and form the cratonic interiors of many continents

characterization of the white ovals on jupiter s southern hemisphere using the first data by the juno jiram instrument during the first perijove passage of the juno mission the jovian infrared auroral mapper jiram observed a line of closely spaced oval features in jupiter s southern hemisphere between 30 s and 45 s in this work we focused on the longitudinal region covering the three ovals having higher contrast at 5 m i e between 120 w and 60 w in system iii coordinates we used the jiram s full spectral capability in the range 2 4 3 m together with a bayesian data inversion approach to retrieve maps of column densities and altitudes for an nh3 cloud and an n2h4 haze the deep under the saturation level volume mixing ratio and the relative humidity for gaseous ammonia were also retrieved our results suggest different vortex activity for the three ovals updraft and downdraft together with considerations about the ammonia condensation could explain our maps providing evidences of cyclonic and anticyclonic structures

a numerical study of the agulhas retroflection the role of bottom topography abstract the oceanic circulation near the eastern margin of the african continent is dominated by the poleward flow of the agulhas current the agulhas current separates from the african coast near the southern tip of the continent makes an abrupt turn to the east known as the agulhas retroflection and flows into the indian ocean as a meandering jet called the agulhas return current the object of this study is to investigate possible causes for the agulhas retroflection a series of process oriented experiments are conducted with the princeton ocean model a primitive equation numerical model in sigma coordinates the model is started from rest forced at its surface with different wind stress distributions and run until dynamical equilibria are reached after which the steady states of the model are analysed in these experiments the effects of inertia wind stress distribution and realistic bottom topography on the agulhas retroflection are analyzed the results of these experiments indicate tha

reconnection and dipolarization driven auroral dawn storms and injections jupiter displays many distinct auroral structures among which auroral dawn storms and auroral injections are often observed contemporaneously however it is unclear if the contemporaneous nature

rare earth element systematics of the chemically precipitated component in early precambrian iron formations and the evolution of the terrestrial atmosphere hydrosphere lithosphere system irrespective of provenance age and metamorphic grade the chemically precipitated component in early precambrian 2 3 ga iron formations ifs displays smyb cn 1 which reflects the corresponding ratios of contemporaneous seawater in conjunction with end if end shale jacobsen and pimentel klose 1988a b this rare earth element ree signature reveals that the ree distribution in early precambrian ifs must be explained by mixing between a marine bottom and a surface water component and that the rees and by analogy the fe cannot be derived from weathering of a continental source eusm n ratios of detritus free ifs are controlled by the marine bottom water component where eusm cn 1 results from ree input from high temperature high t hydrothermal fluids which received their ree signature during high t alteration of oceanic crust at spreading centres decreasing eusm cn of ifs with decreasing depositional age reflect the vaning importance of high t compared to low t 200 c hydrothermal fluids hence oceanic crust alteration for the ree budget of marine bottom waters and are related to decreasing upper mantle temperatures smyb n ratios of detritus free ifs are controlled by the marine surface water component whose ree distribution is affected by the same processes which operate today in the entire ocean mixing calculations reveal that smyb cn in early precambrian marine surface waters was significantly lower than it is today to explain this difference two mechanisms are discussed on the basis of higher pco2 and lower po2 levels of the precambrian atmosphere 1 1 higher co32 in precambrian river and coastal waters and 2 2 redox cycling of the rees at an oceanwide chemocline which separated anoxic and oxic water masses however these processes are synergetic and could have operated in unison the ree distribution in precambrian ifs is described as a result of mixing in a multicomponent system where high t and low t hydrothermal fluids contributed to the marine bottom water and ree input from the dissolved ree pool in river waters after some modification in estuaries dominated the ree distribution in marine surface waters after mixing of bottom and surface waters their combined ree load was quantitatively scavenged onto precipitating iron oxihydroxides or iron carbonates and deposited with the chemically precipitated component after addition of variable amounts of clastic detritus this eventually resulted in the ree distribution observed in precambrian ifs

a survey of small scale waves and wave like phenomena in jupiter s atmosphere detected by junocam in the first 20 orbits of the juno spacecraft around jupiter we have identified a variety of wave like features in images made by its public outreach camera junocam because of juno s unprecedented and repeated proximity to jupiter s cloud tops during its close approaches junocam has detected more wave structures than any previous surveys most of the waves appear in long wave packets oriented east west and populated by narrow wave crests spacing between crests were measured as small as 30 km shorter than any previously measured some waves are associated with atmospheric features but others are not ostensibly associated with any visible cloud phenomena and thus may be generated by dynamical forcing below the visible cloud tops some waves also appear to be converging and others appear to be overlapping possibly at different atmospheric levels another type of wave has a series of fronts that appear to be radiating outward from the center of a cyclone most of these waves appear within 5 of latitude from the equator but we have detected waves covering planetocentric latitudes between 20 s and 45 n the great majority of the waves appear in regions associated with prograde motions of the mean zonal flow juno was unable to measure the velocity of wave features to diagnose the wave types due to its close and rapid flybys however both by our own upper limits on wave motions and by analogy with previous measurements we expect that the waves junocam detected near the equator are inertia gravity waves

neptune and uranus ice or rock giants existing observations of uranus and neptune s fundamental physical properties can be fitted with a wide range of interior models a key parameter in these models is the bulk rock ice ratio and models broadly fall into ice dominated ice giant and rock dominated rock giant categories here we consider how observations of neptune s atmospheric temperature and composition h2 he d h co ch4 h2o and cs can provide further constraints the tropospheric co profile in particular is highly diagnostic of interior ice content but is also controversial with deep values ranging from zero to 0 5 parts per million most existing co profiles imply extreme o h enrichments of 250 times solar composition thus favouring an ice giant however such high o h enrichment is not consistent with d h observations for a fully mixed and equilibrated neptune co and d h measurements can be reconciled if there is incomplete interior mixing ice giant or if tropospheric co has a solely external source and only exists in the upper troposphere rock giant an interior with more rock than ice is also more compatible with likely outer solar system ice sources we primarily consider neptune but similar arguments apply to uranus which has comparable c h and d h enrichment but no observed tropospheric co while both ice and rock dominated models are viable we suggest a rock giant provides a more consistent match to available atmospheric observations this article is part of a discussion meeting issue future exploration of ice giant systems

changes in jupiter s zonal velocity between 1979 and 2008 abstract we show that the peak velocity of jupiter s visible cloud level zonal winds near 24 n planetographic increased from 2000 to 2008 this increase was the only change in the zonal velocity from 2000 to 2008 for latitudes between 70 that was statistically significant and not obviously associated with visible weather we present the first automated retrieval of fast 130 m s 1 zonal velocities at 8 n planetographic latitude and show that some previous retrievals incorrectly found slower zonal winds because the eastward drift of the dark projections associated with 5 m hot spots fooled the retrieval algorithms we determined the zonal velocity in 2000 from cassini images from nasa s planetary data system using a global method similar to previous longitude shifting correlation methods used by others and a new local method based on the longitudinal average of the two dimensional velocity field we obtained global velocities from images acquired in may 2008 with the wide field planetary camera 2 wfpc2 on the hubble space telescope hst longer term variability of the zonal winds is based on comparisons with published velocities based on 1979 voyager 2 and 1995 1998 hst images fluctuations in the zonal wind speeds on the order of 10 m s 1 on timescales ranging from weeks to months were found in the 1979 voyager 2 and the 1995 1998 hst velocities in data separated by 10 h we find that the east west velocity uncertainty due to longitudinal fluctuations are nearly 10 m s 1 so velocity fluctuations of 10 m s 1 may occur on timescales that are even smaller than 10 h fluctuations across such a wide range of timescales limit the accuracy of zonal wind measurements the concept of an average zonal velocity may be ill posed and defining a temporal mean zonal velocity as the average of several zonal velocity fields spanning months or years may not be physically meaningful at 8 n we use our global method to find peak zonal velocities of 110 m s 1 in 2000 and 130 m s 1 in 2008 zonal velocities from 2000 cassini data produced by our local and global methods agree everywhere except in the vicinity of 8 n there the local algorithm shows that the east west velocity has large variations in longitude vast regions exceed 140 m s 1 our global algorithm and all of the velocity extraction algorithms used in previously published studies found the east west drift velocities of the visible dark projections rather than the true zonal velocity at the visible cloud level therefore the apparent increase in zonal winds between 2000 and 2008 at 8 n is not a true change in zonal velocity at 7 3 n the galileo probe found zonal velocities of 170 m s 1 at the 3 bar level if the true zonal velocity at the visible cloud level at this latitude is 140 m s 1 rather than 105 m s 1 then the vertical zonal wind shear is much less than the currently accepted value

jupiter s ionosphere results from the first galileo radio occultation experiment the galileo spacecraft passed behind jupiter on december 8 1995 allowing the first radio occultation measurements of its ionospheric structure in 16 years at ingress 24 s 68 w the principal peak of electron density is located at an altitude of 900 km above the 1 bar pressure level with a peak density of 105 cm 3 and a thickness of 200 km at egress 43 s 28 w the main peak is centered near 2000 km altitude with a peak density of 2 104 cm 3 and a thickness of 1000 km two thin layers possibly forced by upwardly propagating gravity waves appear at lower altitudes in the ingress profile this is the first in a two year series of observations that should help to resolve long standing questions about jupiter s ionosphere

geochemical and petrological evidence for subduction accretion processes in the archean eastern indian craton the composition of sandstones often provides key evidence about the tectonic weathering and transport processes operating on the surface at the time of deposition petrologic and geochemical analyses of little metamorphosed middle late archean sandstones from the eastern indian craton show that the sedimentary rocks were derived from dominantly 3 3 ga old amphibolites of the older metamorphic group omg and tonalites of the older metamorphic tonalite gneisses omtg the two oldest lithologic units of this craton chondrite normalized rare earth element ree patterns of the sandstones show a light ree enriched signature with la sm n varying from 5 2 to 6 7 with no eu anomaly while the heavy rees display flat patterns with gd lu n values of 0 9 1 6 primitive mantle normalized incompatible and compatible trace element plots of these sandstones demonstrate an overall similarity with global proterozoic archean sandstones including strong nb ta negative anomalies in an fsm nd vs ond 0 diagram the sandstones plot precisely between the regional amphibolites and tonalites we infer from the ree abundances and the fsm nd vs ond 0 plot that the sandstones represent a bimodal mechanical mixture of omg and omtg the low ce pb ratios of these rocks of 1 4 indicate a variably pb enriched archean crust and that the ce pb ratio acquired the continental crustal signature distinctly different from those of the bulk silicate earth and mantle values at least as early as mid archean strong nb ta depletion relative to the primitive mantle suggests the sandstones were derived from subduction related magmatic arc sources this latter suggestion is strongly supported by the low nb ta and high zr sm ratios of these sandstones identical to archean tonalite trondhjemites that require based on recent trace element partitioning results their protoliths to have formed by subduction melting of lowmagnesium amphibolites or metamorphosed hydrous basalts 1 2 the average nd model ages of the sandstones are greater than the sm nd crystallization ages of the omg and omtg at v3 3 ga the geochemical data presented here can be collectively interpreted to suggest the presence of subduction accretion processes operational in the midarchean eastern indian craton because the omg and omtg the source rocks of the sandstones formed in a subduction related arc setting the basement rocks upon which this arc was constructed must have been older this observation and the depleted mantle nd model ages tdm of the sandstones ranging from 3 6 to 4 0 ga strongly indicate the presence of continental crust in this eastern indian craton older than 3 3 ga and possibly as old as

auroral evidence of io s control over the magnetosphere of jupiter 1 contrary to the case of the earth the main auroral oval on jupiter is related to the breakdown of plasma corotation in the middle magnetosphere even if the root causes for the main auroral emissions are io s volcanism and jupiter s fast rotation changes in the aurora could be attributed either to these internal factors or to fluctuations of the solar wind here we show multiple lines of evidence from the aurora for a major internally controlled magnetospheric reconfiguration that took place in spring 2007 hubble space telescope far uv images show that the main oval continuously expanded over a few months engulfing the ganymede footprint on its way simultaneously there was an increased occurrence rate of large equatorward isolated auroral features attributed to injection of depleted flux tubes furthermore the unique disappearance of the io footprint on 6 june appears to be related to the exceptional equatorward migration of such a feature the contemporary observation of the spectacular tvashtar volcanic plume by the new horizons probe as well as direct measurement of increased io plasma torus emissions suggest that these dramatic changes were triggered by io s volcanic activity

comparison of isotopic and petrographic provenance indicators in sediments from tertiary continental basins of new mexico abstract isotopic variations of nd in sedimentary rocks provide a new tool for provenance determination we have compared the isotopic technique with classic petrographic indicators of provenance in sediments from two tertiary basins of the rio grande rift north central new mexico the siliciclastic sediments in these basins were derived from varying proportions of precambrian basement and oligocene volcanic rocks which are isotopically and petrographically distinct in the analyzed sediments a good correspondence exists between petrographic and isotopic provenance indicators the data also suggest that the isotopic tracer is more sensitive to minor detrital input from a second source than is the framework petrology the similar sm nd ratios for all analyzed sediments and the identical isot pic values of interlayered mudstone and sandstone indicate that no significant fractionation of sm and nd occurs during the formation of the sediments thus the nd model ages of the sediments preserve the crust formation age of the source the sr isotopic and concentration data show trends generally similar to the nd data but they do not indicate the sedimentary provenance as clearly this ambiguity is a consequence of strong rb sr source heterogeneities and rb sr fractionation during the sedimentary cycle

small lightning flashes from shallow electrical storms on jupiter lightning flashes have been observed by a number of missions that visited or flew by jupiter over the past several decades imagery led to a flash rate estimate of about 4 10 3 flashes per square kilometre per year refs 1 2 the spatial extent of voyager flashes was estimated to be about 30 kilometres half width at half maximum intensity hwhm but the camera was unlikely to have detected the dim outer edges of the flashes given its weak response to the brightest spectral line of jovian lightning emission the 656 3 nanometre h line of atomic hydrogen1 3 6 the spatial resolution of some cameras allowed investigators to confirm 22 flashes with hwhm greater than 42 kilometres and to estimate one with an hwhm of 37 to 45 kilometres refs 1 7 9 these flashes with optical energies comparable to terrestrial superbolts of 0 02 1 6 1010 joules have been interpreted as tracers of moist convection originating near the 5 bar level of jupiter s atmosphere assuming photon scattering from points beneath the clouds 1 3 7 8 10 12 previous observations of lightning have been limited by camera sensitivity distance from jupiter and long exposures about 680 milliseconds to 85 seconds meaning that some measurements were probably superimposed flashes reported as one1 2 7 9 10 13 here we report optical observations of lightning flashes by the juno spacecraft with energies of approximately 105 108 joules flash durations as short as 5 4 milliseconds and inter flash separations of tens of milliseconds with typical terrestrial energies the flash rate is about 6 1 10 2 flashes per square kilometre per year more than an order of magnitude greater than hitherto seen several flashes are of such small spatial extent that they must originate above the 2 bar level where there is no liquid water14 15 this implies that multiple mechanisms for generating lightning on jupiter need to be considered for a full understanding of the planet s atmospheric convection and composition small lightning flashes detected on jupiter by juno have shallow origins above the 2 bar level of jupiter s atmosphere where temperatures are too low for liquid water to exist

changes in jupiter s zonal wind profile preceding and during the juno mission abstract we present five epochs of wfc3 hst jupiter observations taken between 2009 2016 and extract global zonal wind profiles for each epoch jupiter s zonal wind field is globally stable throughout these years but significant variations in certain latitude regions persist we find that the largest uncertainties in the wind field are due to vortices or hot spots and show residual maps which identify the strongest vortex flows the strongest year to year variation in the zonal wind profiles is the 24 n jet peak numerous plume outbreaks have been observed in the northern temperate belt and are associated with decreases in the zonal velocity and brightness we show that the 24 n jet peak velocity and brightness decreased in 2012 and again in late 2016 following outbreaks during these years our february 2016 zonal wind profile was the last highly spatially resolved measurement prior to juno s first science observations the final 2016 data were taken in conjunction with juno s perijove 3 pass on 11 december 2016 and show the zonal wind profile following the plume outbreak at 24 n in october 2016

the dusk flank of jupiter s magnetosphere limited single spacecraft observations of jupiter s magnetopause have been used to infer that the boundary moves inward or outward in response to variations in the dynamic pressure of the solar wind at earth multiple spacecraft observations have been implemented to understand the physics of how this motion occurs because they can provide a snapshot of a transient event in progress here we present a set of nearly simultaneous two point measurements of the jovian magnetopause at a time when the jovian magnetopause was in a state of transition from a relatively larger to a relatively smaller size in response to an increase in solar wind pressure the response of jupiter s magnetopause is very similar to that of the earth confirming that the understanding built on studies of the earth s magnetosphere is valid the data also reveal evidence for a well developed boundary layer just inside the magnetopause

2 8 ga old anorogenic granite acid volcanics association from western margin of the singhbhum orissa craton eastern india abstract the tamperkola granite acid volcanics association occurring at the western margin of the archaean singhbhum orissa iron ore craton soc eastern india is intrusive into the darjing group which represents a sequence of mobile belt metasediments in this part of the soc the darjing group rests unconformably on the bonai granite 3 2 ga old absence of any deformational imprints of the country rock metasediments on the tamperkola granite acid volcanics together with its undeformed and unmetamorphosed nature its alkali feldspar dominant mineralogy and its high sio 2 and na 2 o k 2 o and low mgo and cao contents suggest that this granite acid volcanics association is anorogenic in nature two representative samples one each from the granite and the acid volcanics have been dated by in situ 207 pb 206 pb zircon dating method using a small ion microprobe minimum age of crystallisation of the acid volcanics is found to be 2 8 ga strong peak in the 207 pb 206 pb frequency diagram and equality of the observed and expected errors in radiogenic 207 pb 206 pb ratios suggest that this age probably represents the true age of formation of the volcanics the age data place the deposition and metamorphism of the mobile belt metasediments of the darjing group in between 3 2 and 2 8 ga occurrence of 2 9 2 8 ga old small granitoid plutons alkali feldspar granite to syenogranite in composition is also known from the southern margin of the soc therefore it appears that around 2 9 2 8 ga small alkali granite bodies formed at the marginal part of this cratonic block after its stabilisation at 3 1 ga

the archaean nucleus of singhbhum the present state of knowledge abstract the supracrustal rocks of the older metamorphic group omg consisting of metasediments and ortho amphibolite constitute the oldest unit in the archaean nucleus of singhbhum however there are indications that still older 3 4 3 8 ga crust of both sialic and mafic composition existed in this region the omg ortho amphibolites were formed by partial melting of mantle with near chondritic composition ca 3 3 ga ago probably as a result of plume activity shortly afterwards partial melting of the underplated mafic material produced a tonalitic melt older metamorphic tonalitic gneiss omtg which intruded the omg supracrustals and the entire suite was deformed and metamorphosed to upper amphibolite facies subsequent to this melting of the omg ortho amphibolites and the lower crustal material of probable andesitic composition produced melts varying in composition from tonalite to granite and these intruded in different phases to produce plutons of singhbhum granite bonai granite and kaptipada granite which together form volumetrically the major part of the archaean nucleus the older omg and omtg occur as enclaves within these younger granitoids the time difference between the emplacements of the omtg and the early phases of younger granitic intrusion was of the order of 100 200 ma thus serial additions of juvenile material led to the formation of a stable microcontinent by 3 2 ga thermally triggered stretching in this microcontinent produced basins peripheral to the present day singhbhum granite pluton and in these basins the younger supracrustal rocks of the iron ore group iog consisting of bif associated argillaceous and subordinate arenaceous rocks and mafic lavas were laid down there is inadequate field or geochronological evidence to resolve the issue of whether the different iron ore basins were coeval or not meagre geochronological data suggest that some of the bifs are older than ca 3 1 ga post iog activity is confined to the intrusion of mafic dyke swarms and formation of intracratonic basins the ages of both being uncertain

the first close up images of jupiter s polar regions results from the juno mission junocam instrument during juno s first perijove encounter the junocam instrument acquired the first images of jupiter s polar regions at 50 70 km spatial scale at low emission angles poleward of 64 68 planetocentric latitude where jupiter s east west banded structure breaks down several types of discrete features appear on a darker background cyclonic oval features are clustered near both poles other oval shaped features are also present ranging in size from 2000 km down to junocam s resolution limits the largest and brightest features often have chaotic shapes two narrow linear features in the north associated with an overlying haze feature traverse tens of degrees of longitude junocam also detected an optically thin cloud or haze layer past the northern nightside terminator estimated to be 58 21 km approximately three scale heights above the main cloud deck junocam will acquire polar images on every perijove allowing us to track the state and evolution of longer lived features

retroflection of part of the east greenland current at cape farewell the east greenland current egc and the smaller east greenland coastal current egcc provide the major conduit for cold fresh polar water to enter the lower latitudes of the north atlantic they flow equatorward through the western irminger basin and around cape farewell into the labrador sea the surface circulation and transport of the cape farewell boundary current region in summer 2005 is described the egcc merges with arctic waters of the egc to the south of cape farewell forming the west greenland current the egc transport decreases from 15 5 sv south of cape farewell to 11 7 sv in the eastern labrador sea where the water becomes known as irminger sea water the decrease in egc transport is balanced by the retroflection of a substantial proportion of the boundary current 5 1 sv into the central irminger basin a new pathway for fresh water into the interior of the subpolar gyre

on sverdrup discontinuities and vortices in the southwest indian ocean abstract the southwest indian ocean is distinguished by discontinuities in the wind driven sverdrup circulation these connect the northern and southern tips of madagascar with africa and the southern tip of africa with south america in an analytical barotropic model with a flat bottom the discontinuities produce intense westward jets those off the northern tip of madagascar and the southern tip of africa are always present while the strength of that off southern madagascar depends on the position of the zero curl line in the indian ocean the jet is strong if the line intersects madagascar but weak if the line is north of the island all three jets are barotropically unstable by the rayleigh kuo criterion the authors studied the development of the instability using a primitive equation model with a flat bottom and realistic coastlines the model produced westward jets at the three sites and these became unstable after several weeks generating 200 300 km scale eddies the eddies generated west of

nd sr isotopic provenance and trace element geochemistry of amazonian foreland basin fluvial sands bolivia and peru implications for ensialic andean orogeny nd and sr isotopes and the trace element contents including the rare earths were determined for fluvial sands of lithic arenite composition from the madre de dios foreland basin of bolivia and peru on standard petrologic ternary diagrams the sands fall in the recycled orogen provenance field and thus are similar to typical ancient foreland basin composition the average rare earth elemental pattern of the sands is identical to the upper continental crustal average as estimated from post archean composite shales of different continents ratios ofth u co th la sc and th sc of the fluvial sands are intermediate between an average magmatic arc and an upper crustal average compositions the dispersion of some trace elemental patterns in the sands can be attributed to fractionation of dense minerals including zircon during the sedimentation process the variations of nd isotopes in conjunction with the petrographic parameters of lithic metamorphic lm and volcanic lv fragments allow a two fold classification of the sands these two sand types can be interpreted in terms of mixing among three different provenances one volcanic rock suite with less negativeend o parameter than the other volcanic suite and a third metasedimentary source withend o value of around 12 which is considered to be similar to the average western brazilian shield composition thus the overall compositions of the sands has been modeled as mechanical mixtures of two components an andean magmatic arc and the brazilian shield derived metasediments the model is strongly supported by a plot ofend o versusesr o of the sands in this plot the type 1 and 2 sands define two coherent hyperbolic trends contiguous with two different portions of the andean magmatic trend this relationship has been interpreted to indicate that the observed andean magmatic trend in anesr o end o diagram is the result of varying degrees of contamination of a primitive arc type magma by the precambrian continental crust of the western brazilian shield the depleted mantle average nd model age of 1 46 ga for the fluvial sands reflects the average age of the brazilian continental crustal source the development of the andean orogenic belt has been discussed schematically with the isotopic data of the sands the model describes a trailing edge prism of sediments derived from the brazilian shield during the late paleozoic early mesozoic the prism becomes part of the fold thrust belt during the andean orogeny in the neogene when the foreland basin develops with the basin fill partly derived from the fold thrust belt the sedimentary rocks in the fold thrust belt are also a major source of contaminants for the andean magmas the contiguous nature of the andean magmatic trend and the fluvial sand data in theesr o end o diagram suggests that the ensialic andean magmatic arc has remained connected to its parent continent the western brazilian shield throughout the development of the andean orogeny

the structural and geochemical evolution of the singhbhum granite batholithic complex india abstract the singhbhum granite batholithic complex of eastern india is composed mainly of a the older metamorphic group tonalite trondhjemite gneiss omtg 3800 ma old whch intruded synkinematically into the enveloping older metamorphic group omg 3800 ma old and b the singhbhum granite sbg consisting of three distinct but closely related phases of at least twelve separate magmatic units of granodiorite granite 2950 ma old and a number of patches of granitised omg orthoamphibolites geochemical studies including ree and lil elements suggest that a the omg orthoamphibolites were derived either by re melting of a k poor basalt lkt or of mantle peridotite with high concentration of lil elements b the omg tonalite was derived by partial melting of amphibolite and c the singhbhum granite magmas appear to have formed in two distinct modes i partial melting of amphibolite for the magmas of phases i and ii and ii partial melting of a siliceous garnet bearing granulite for magmas of the phase iii units

diagenetic and metamorphic history of the umm nar bif eastern desert egypt the umm nar bif was formed in a sedimentary environment it is confined to an upper stratigraphic zone of pre pan african metamorphosed shelf deposits during the pan african deformational history the bif and the host metasediments were tectonically overlain by ophiolitic melange succession the metasediments and the melange were subjected to a major folding phase and then thrust over the shaitian sheared granite prior to the intrusion of syn to late orogenic granitoids the bif is divisible into two main types oxide bands including magnetite and hematite and oxide silicate bands including magnetite hematite and stilpnomelane the associated gangues are quartz calcite epidote garnet plagioclase graphite and muscovite rhythmic banding and lamination cross lamination and flaser structure are the most prominent primary features in the if bands the iron minerals and the associated gangue show a variety of textural aspects and microscopic interrelationships which indicate successive episodes of mineral accumulation and formation involving deposition recrystallization blastic growths overgrowths replacement and deformations during continuous burial and subsequent tectonic deformations

anelastic torsional oscillations in jupiter s metallic hydrogen region abstract we consider torsional alfven waves which may be excited in jupiter s metallic hydrogen region these axisymmetric zonal flow fluctuations have previously been examined for incompressible fluids in the context of earth s liquid iron core theoretical models of the deep seated jovian dynamo implementing radial changes of density and electrical conductivity in the equilibrium model have reproduced its strong dipolar magnetic field analysing such models we find anelastic torsional waves travelling perpendicular to the rotation axis in the metallic region on timescales of at least several years being excited by the more vigorous convection in the outer part of the dynamo region they can propagate both inwards and outwards when being reflected at a magnetic tangent cylinder at the transition to the molecular region they can form standing waves identifying such reflections in observational data could determine the depth at which the metallic region effectively begins also this may distinguish jovian torsional waves from those in earth s core where observational evidence has suggested waves mainly travelling outwards from the rotation axis these waves can transport angular momentum and possibly give rise to variations in jupiter s rotation period of magnitude no greater than tens of milliseconds in addition these internal disturbances could give rise to a 10 change over time in the zonal flows at a depth of 3000 km below the surface

clusters of cyclones encircling jupiter s poles the familiar axisymmetric zones and belts that characterize jupiter s weather system at lower latitudes give way to pervasive cyclonic activity at higher latitudes two dimensional turbulence in combination with the coriolis effect that is the large meridionally varying coriolis force on the giant planets of the solar system produces alternating zonal flows the zonal flows weaken with rising latitude so that a transition between equatorial jets and polar turbulence on jupiter can occur simulations with shallow water models of giant planets support this transition by producing both alternating flows near the equator and circumpolar cyclones near the poles jovian polar regions are not visible from earth owing to jupiter s low axial tilt and were poorly characterized by previous missions because the trajectories of these missions did not venture far from jupiter s equatorial plane here we report that visible and infrared images obtained from above each pole by the juno spacecraft during its first five orbits reveal persistent polygonal patterns of large cyclones in the north eight circumpolar cyclones are observed about a single polar cyclone in the south one polar cyclone is encircled by five circumpolar cyclones cyclonic circulation is established via time lapse imagery obtained over intervals ranging from 20 minutes to 4 hours although migration of cyclones towards the pole might be expected as a consequence of the coriolis effect by which cyclonic vortices naturally drift towards the rotational pole the configuration of the cyclones is without precedent on other planets including saturn s polar hexagonal features the manner in which the cyclones persist without merging and the process by which they evolve to their current configuration are unknown

archean greenstone belt magmatism and the continental growth mantle evolution connection constraints from th u nb lree systematics of the 2 7 ga wawa subprovince superior province canada abstract an extensive database including th u nb ree systematics for diverse magmatic and sedimentary lithologies of 2 7 ga wawa greenstone belts provide new constraints on the mechanism of crustal growth in the southern superior province and controls on its composition the greenstone belts are characterized by collages of oceanic plateaus oceanic island arcs and trench turbidites these lithotectonic fragments were tectonically assembled in a large subduction accretion complex following juxtaposition these diverse lithologies were collectively intruded by syn kinematic ttg tonalite trondhjemite granodiorite plutons and ultramafic to felsic dykes and sills with subduction zone geochemical signatures intra oceanic basalts are characterized by near flat ree patterns and nb u and nb th ratios generally greater than primitive mantle values consistent with positive nd values they are associated with komatiites the association being interpreted as an ocean plateau sequence erupted from a mantle plume bimodal arc volcanic sequences trench turbidites and contemporaneous ttg suites are characterized by fractionated ree with nb u and nb th ratios less than primitive mantle values mixing hyperbolae between oceanic plateau and magmatic arc sequences pass through the estimated composition of bulk continental crust suggesting that crustal growth in the late archean was by tectonic sedimentary and chemical mixing of oceanic plateau and arc sequences at convergent plate boundaries mixing calculations suggest that oceanic plateau and subduction zone components in the wawa continental crust are represented by 6 12 and 88 94 respectively high nb u and nb th ratios of plateau tholeiitic basalts are interpreted as a complementary reservoir to arc magmatism low nb u and nb th hundreds of millions of years prior to recycling of oceanic lithosphere through a subduction zone high nb u nb th and its incorporation into a mantle plume from which 2 7 ga plateau tholeiites erupted the variably high nb u ratios of the plateau basalts are consistent with early extraction of large quantities of the protoliths magmatic precursor of continental crust from the southern superior province asthenospheric mantle

long term tracking of circumpolar cyclones on jupiter from polar observations with junocam abstract we use observations from the junocam instrument on the juno spacecraft to map the polar regions of jupiter between 2016 and 2018 these polar maps track the long term evolution of the pentagonal and octagonal structures of circumpolar cyclones cpcs the south polar pentagonal and north polar octagonal arrangements of the cpcs have remained largely stable over the last 2 years of observation the morphologies of individual cyclones also remain largely stable for 1 2 years although some changes are observed so that the location of each cpc is uniquely identifiable at both north and south poles individual cyclones move around the center to a limited extent and there is a gap of variable width between one pair of south polar cpcs measurements at consecutive closest approaches perijoves 53 days apart show small movements of individual cyclones both eastward and westward however the south polar cpcs have a long term systematic westward drift rate of 1 5 0 2 per orbit or 0 040 0 005 m s whereas north polar cpcs do not show a consistent drift in longitude around the perimeter of the southern pentagon we detect no rapid jet in short term animations and we provide evidence that anticyclonic white ovals may have a range of longitudinal drifts between 44 and 15 per orbit 1 8 to 0 7 m s measurement of the angular velocities within the cyclones shows increasing angular velocity with decreasing radius except in the inner bright cloud deck of one class of northern cpcs which are inferred to have smaller or even negative angular velocities very near the center tangential wind velocities within the cyclones range up to 100 m s and even 100 m s in the southern polar cyclone and are maximal between radii of 900 1600 km overall we find that the behavior of the polar cyclones constellations compares well to vortex crystal theory even though the theory does not include anticyclonic vorticity

quantification of the effects of secondary matrix on the analysis of sandstone composition and a petrographic chemical technique for retrieving original framework grain modes of altered sandstones abstract most studies of sandstone provenance involve modal analysis of framework grains using techniques that exclude the fine grained breakdown products of labile mineral grains and rock fragments usually termed secondary matrix or pseudomatrix however the data presented here demonstrate that when the proportion of pseudomatrix in a sandstone exceeds 10 standard petrographic analysis can lead to incorrect provenance interpretation petrographic schemes for provenance analysis such as qfl and qfr should not therefore be applied to sandstones containing more than 10 secondary matrix pseudomatrix is commonly abundant in sandstones and this is therefore a problem for provenance analysis the difficulty can be alleviated by the use of whole rock chemistry in addition to petrographic analysis combination of chemical and point count data permits the construction of normative compositions that approximate original framework grain compositions provenance analysis is also complicated in many cases by fundamental compositional alteration during weathering and transport many sandstones particularly shallow marine deposits have undergone vigorous reworking which may destroy unstable mineral grains and rock fragments in such cases it may not be possible to retrieve provenance information by either petrographic or chemical means because of this pseudomatrix rich sandstones should be routinely included in chemical petrological provenance analysis because of the many factors both pre and post depositional that operate to increase the compositional maturity of sandstones petrologic studies must include a complete inventory of matrix proportions grain size and sorting parameters and an assessment of depositional setting

infrared observations of io from juno abstract the jovian infrared auroral mapper jiram on board the nasa juno spacecraft is a dual band imager and spectrometer primarily designed to study the jovian atmosphere and aurorae in addition to its primary goal jiram has been used to obtain images and spectra of the galilean satellites jupiter s largest moons when the spacecraft attitude was favourable to achieve this goal here we present jiram s first images and spectra of io these observations are used to characterize the location and possible morphology and some temperatures of io s volcanic thermal sources the identification of so2 and the possible identification of other materials a new hot spot volcano is identified close to the south pole of io and others are seen in lower latitude regions which were previously unmapped images of the same region taken 2 months apart also show variations of hot spot intensity possibly due to new lava flows or to lava flow breakouts

preliminary jiram results from juno polar observations 2 analysis of the jupiter southern h3 emissions and comparison with the north aurora the jupiter infrared auroral mapper jiram aboard juno observed the jovian south pole aurora during the first orbit of the mission h3 trihydrogen cation and ch4 methane emissions have been identified and measured the observations have been carried out in nadir and slant viewing both by a l filtered imager and a 2 5 m spectrometer results from the spectral analysis of the all observations taken over the south pole by the instrument are reported the coverage of the southern aurora during these measurements has been partial but sufficient to determine different regions of temperature and abundance of the h3 ion from its emission lines in the 3 4 m wavelength range finally the results from the southern aurora are also compared with those from the northern ones from the data taken during the same perijove pass and reported by dinelli et al 2017

origin of jupiter s cloud level zonal winds remains a puzzle even after juno how far jupiter s cloud level zonal winds penetrate into its interior a question related to the origin of the winds has long been a major puzzle about jupiter there exist two different views the shallow scenario in which the cloud level winds are confined within the thin weather layer at cloud top and the deep scenario in which the cloud level winds manifest thermal convection in the deep interior we interpret using two different models corresponding to the two scenarios the high precision measurements of jupiter s equatorially antisymmetric gravitational field by the juno spacecraft we demonstrate based on the thermal gravitational wind equation that both the shallow and deep cloud level winds models are capable of explaining the measured odd gravitational coefficients within the measured uncertainties reflecting the nonunique nature of the gravity inverse problem we conclude that the high precision juno gravity measurements cannot provide an answer to the long standing question about the origin of jupiter s cloud level zonal winds

preliminary results on the composition of jupiter s troposphere in hot spot regions from the jiram juno instrument the jupiter infrared auroral mapper jiram instrument on board the juno spacecraft performed observations of two bright jupiter hot spots around the time of the first juno pericenter passage on 27 august 2016 the spectra acquired in the 4 5 m spectral range were analyzed to infer the residual opacities of the uppermost cloud deck as well as the mean mixing ratios of water ammonia and phosphine at the approximate level of few bars our results support the current view of hot spots as regions of prevailing descending vertical motions in the atmosphere but extend this view suggesting that upwelling may occur at the southern boundaries of these structures comparison with the global ammonia abundance measured by juno microwave radiometer suggests also that hot spots may represent sites of local enrichment of this gas jiram also identifies similar spatial patterns in water and phosphine contents in the two hot spots

resetting of neodymium isotopes and redistribution of rees during sedimentary processes the early proterozoic chelmsford formation sudbury basin ontario canada abstract the rees abundances and neodymium isotope compositions of sandstones and siltstones from the early proterozoic chelmsford formation reveal that the rees in some samples were redistributed during the early proterozoic by surficial processes and that prior to redistribution the nd isotope system was partially reset the chelmsford formation is a coarse grained turbidite sequence the youngest of three clastic units that fill the sudbury basin in ontario it is constrained to have been derived from nearby late archean superior province rocks by petrography major and trace element chemistry and pb isotopic compositions of whole rocks and feldspar although ree patterns and nd model ages for samples from around the base of the formation reflect their derivation from undisturbed superior province rocks tdm 2800 ma five samples from higher in the stratigraphic section show evidence that up to 60 of their la has been removed and sm nd has increased by up to 60 these samples also have anomalously high nd model ages tdm 3400 to 4400 ma the presence of pronounced positive ce anomalies in the samples with anomalous tdm indicates the influence of surficial processes on the ree composition the data scatter about a vertical array on a plot of f sm nd vs ndt 1800 nd calculated at 1800 ma approximately the depositional age with values of f sm nd between 0 45 and 0 14 mixing of nd from other sources is difficult to reconcile with the petrography major and trace element geochemistry and nd and pb isotopes removal of an lree enriched phase from the sedimentary system provides a viable mechanism to produce the ree and nd isotopic characteristics of the chelmsford formation samples neodymium isotopes require that this phase was partially isotopically equilibrated with the matrix sediment near the time of sedimentation this study shows the dangers of indiscriminate use of nd model ages in provenance studies and demonstrates that the simultaneous examination of sm nd and nd isotopes on f sm nd vs nd or isochron plots is required for the recognition of sedimentary redistribution of the ree

morphology of the uv aurorae jupiter during juno s first perijove observations on 27 august 2016 the nasa juno spacecraft performed its first close up observations of jupiter during its perijove here we present the uv images and color ratio maps from the juno uvs uv imaging spectrograph acquired at that time data were acquired during four sequences three in the north one in the south from 5 00 ut to 13 00 ut from these observations we produced complete maps of the jovian aurorae including the nightside the sequence shows the development of intense outer emission outside the main oval first in a localized region 255 295 system iii longitude and then all around the pole followed by a large nightside protrusion of auroral emissions from the main emission into the polar region some localized features show signs of differential drift with energy typical of plasma injections in the middle magnetosphere finally the color ratio map in the north shows a well defined area in the polar region possibly linked to the polar cap

eastern indian 3800 million year old crust and early mantle differentiation samarium neodymium data for nine granitic and tonalite gneisses occurring as remnants within the singhbhum granite batholith in eastern india define an isochron of age 3775 89 x 10 6 years with an initial 143 nd 144 nd ratio of 0 50798 0 00007 this age contrasts with the rubidium strontium age of 3200 x 10 6 years for the same suite of rocks on the basis of the new samarium neodynium data field data and petrologic data a scheme of evolution is proposed for the archean crust in eastern india the isotopic data provide evidence that parts of the earth s mantle were already differentiated with respect to the chondritic samarium neodymium ratio 3800 x l0 6 years ago