preliminary assessment of resources and economic potential of individual gas hydrate accumulations in the gulf of mexico continental slope abstract some global estimates suggest that gas hydrates represent the largest reservoir of fossil fuel however only a few studies of the resource and economic potential of individual gas hydrate accumulations exist here we estimate the volume of hydrate bound gas at gc green canyon blocks 184 185 gc 234 235 gb garden banks 388 mc mississippi canyon 798 842 gc 204 mc 852 853 and at atwater valley 425 426 sites in the gulf of mexico at water depths 500 2000 m the structural accumulations may contain from 4 7 10 8 to 1 3 10 11 m 3 of gas at standard temperature and pressure the resources in individual gas hydrate accumulations are comparable by volume with the reserves in very small to major conventional gas fields various geologic technologic and economic factors affect the economic potential of studied accumulations the mc 852 853 appears to be characterized by the most favorable combination of these factors and thus is suggested to have the highest economic potential the economic potential of gas hydrate accumulations at gc 204 gb 388 and at 425 426 sites is ranked as average gas hydrate accumulations at gc 234 235 gc 184 185 and mc 798 842 sites contain only small volumes of hydrate bound gas and likely have no economic potential future gas hydrate research should focus on the detailed study of large structural gas hydrate accumulations from which gas may be profitably recovered e g the mc 852 853 site

loki io a periodic volcano loki is the most powerful volcano in the solar system it has been observed to be in continuous though variable activity since 1979 synthesis of more than a decade of groundbased data suggests that loki eruptions are cyclic with a 540 day period application of a simple lava cooling model to temperatures in loki patera and eruption start and end times implies that brightenings are due to a resurfacing wave propagating across the patera the data are most consistent with lava lake overturn but resurfacing by lava flows cannot be ruled out a porosity gradient in the lake crust could cause lava lake overturn to occur periodically on the timescale observed

paleoecological control of ostracode distribution in a pennsylvanian auernig cyclothem of the carnic alps austria abstract pennsylvanian kasimovian ostracodes from the lower part of the auernig group carnic alps austria inhabited a shallow marine and open marine environment paleontological investigations of two ostracode faunas brought significant differences between the ostracode assemblage of the anthracoporella dasycladalean algae mound environment and the one from the overlying nodular limestone additionally paleoecological data are obtained from the overall microfacies of mound and mound cover rocks and from their respective fossil associations these data are used to interpret ostracode environments mound ostracode assemblages show a smaller number of dominant species contain remarkably tiny forms for example the bolliid solleikope parva fohrer 1991 and are dominated by smooth shelled to less ornamented carapaces this is probably because large size and sculpture elements such as spines and thorns would have been restricting for a life in an anthracoporella jungle some species for example carnizzia auricula fohrer 1997b are adapted to the mound environment because of their morphological features and are very rare to absent outside of the anthracoporella mounds ostracode faunas collected from the overlying nodular limestone are completely different they are characterized by a higher number of dominant species and show a broad variety of morphological features these faunas are dominated by the highly ornamented members of the families amphissitidae scrobiculidae kirkbyidae kellettinidae and paraparchitidae representatives of the family bairdiidae e g bairdia are the most abundant species in anthracoporella mounds and in the mound cover rocks this group of ostracodes requires open marine and shallow marine conditions but within these parameters there is a high paleoecological tolerance with regard to these paleoecological limits bairdia is an opportunistic species anthracoporella mound ostracodes of other pennsylvanian shelf regions have so far not been reported as to the mound cover ostracodes there are close relationships of the carnic alps ostracodes to those of the cantabrian mountains spain

new estimates for io eruption temperatures implications for the interior abstract the initial interpretation of galileo data from jupiter s moon io suggested eruption temperatures 1600 c tidal heating models have difficulties explaining io s prodigious heat flow if the mantle is 1300 c although we suggest that temperatures up to 1450 c may be possible in general io eruption temperatures have been overestimated because the incorrect thermal model has been applied much of the thermal emission from high temperature hot spots comes from lava fountains but lava flow models were utilized we apply a new lava fountain model to the highest reported eruption temperature the ssi observation of the 1997 eruption at pillan this resets the lower temperature limit for the eruption from 1600 to 1340 c additionally viscous heating of the magma may have increased eruption temperature by 50 100 c as a result of the strong compressive stresses in the ionian lithosphere while further work is needed it appears that the discrepancy between observations and interior models is largely resolved

imaging of volcanic activity on jupiter s moon io by galileo during the galileo europa mission and the galileo millennium mission the solid state imaging ssi instrument provided the first high and medium resolution views of io as the galileo spacecraft closed in on the volcanic body in late 1999 and early 2000 while each volcanic center has many unique features the majority can be placed into one of two broad categories the promethean eruptions typified by the volcanic center prometheus are characterized by long lived steady eruptions producing a compound flow field emplaced in an insulating manner over a period of years of decades in contrast pillanian eruptions are characterized by large pyroclastic deposits and short lived but high effusion rate eruptions from fissures feeding open channel or open sheet flows both types of eruptions commonly have 100 km tall bright so2 rich plumes forming near the flow fronts and smaller deposits of red material that mark the vent for the silicate lavas

volcanic activity at tvashtar catena io abstract galileo s solid state imager ssi observed tvashtar catena four times between november 1999 and october 2001 providing a unique look at a distinctive high latitude volcanic complex on io the first observation orbit i25 november 1999 resolved for the first time an active extraterrestrial fissure eruption the brightness temperature was at least 1300 k the second observation orbit i27 february 2000 showed a large 500 km 2 region with many small hot regions of active lava the third observation was taken in conjunction with cassini imaging in december 2000 and showed a pele like annular plume deposit the cassini images revealed an 400 km high pele type plume above tvashtar catena the final galileo ssi observation of tvashtar orbit i32 october 2001 revealed that obvious to ssi activity had ceased although data from galileo s near infrared mapping spectrometer nims indicated that there was still significant thermal emission from the tvashtar region in this paper we primarily analyze the style of eruption during orbit i27 february 2000 comparison with a lava flow cooling model indicates that the behavior of the tvashtar eruption during i27 does not match that of simple advancing lava flows instead it may be an active lava lake or a complex set of lava flows with episodic overlapping eruptions the highest reliable color temperature is 1300 k although higher temperatures cannot be ruled out they do not need to be invoked to fit the observed data the total power output from the active lavas in february 2000 was at least 10 11 w

chemosynthetic mussels at a brine filled pockmark in the northern gulf of mexico a large 540 square meters bed of bathymodiolus n sp mytilidae bivalvia rings a pool of hypersaline 121 35 practical salinity units brine at a water depth of 650 meters on the continental slope south of louisiana the anoxic brine dissolved oxygen 0 17 milliliters per liter contains high concentrations of methane which nourishes methanotrophic symbionts in the mussels the brine which originates from a salt cored diapir that penetrates to within 500 meters ofthe sea floor fills a depression that was evidently excavated by escaping gas the spatial continuity of the mussel bed indicates that the brine level has remained fairly constant however demographic differences between the inner and outer parts of the bed record small fluctuations

lava lakes on io observations of io s volcanic activity from galileo nims during the 2001 fly bys abstract galileo s near infrared mapping spectrometer nims obtained its final observations of io during the spacecraft s fly bys in august i31 and october 2001 i32 we present a summary of the observations and results from these last two fly bys focusing on the distribution of thermal emission from io s many volcanic regions that give insights into the eruption styles of individual hot spots we include a compilation of hot spot data obtained from galileo voyager and ground based observations at least 152 active volcanic centers are now known on io 104 of which were discovered or confirmed by galileo observations including 23 from the i31 and i32 io fly by observations presented here we modify the classification scheme of keszthelyi et al 2001 j geophys res 106 e12 33 025 33 052 of io eruption styles to include three primary types promethean lava flow fields emplaced as compound pahoehoe flows with small plumes 200 km high plumes and rapidly emplaced flow fields and a new style we call lokian that includes all eruptions confined within paterae with or without associated plume eruptions thermal maps of active paterae from nims data reveal hot edges that are characteristic of lava lakes comparisons with terrestrial analogs show that io s lava lakes have thermal properties consistent with relatively inactive lava lakes the majority of activity on io based on locations and longevity of hot spots appears to be of this third type this finding has implications for how io is being resurfaced as our results imply that eruptions of lava are predominantly confined within paterae thus making it unlikely that resurfacing is done primarily by extensive lava flows our conclusion is consistent with the findings of geissler et al 2004 icarus this issue that plume eruptions and deposits rather than the eruption of copious amounts of effusive lavas are responsible for io s high resurfacing rates the origin and longevity of islands within ionian lava lakes remains enigmatic

io volcanism seen by new horizons a major eruption of the tvashtar volcano jupiter s moon io is known to host active volcanoes in february and march 2007 the new horizons spacecraft obtained a global snapshot of io s volcanism a 350 kilometer high volcanic plume was seen to emanate from the tvashtar volcano 62 n 122 w and its motion was observed the plume s morphology and dynamics support nonballistic models of large io plumes and also suggest that most visible plume particles condensed within the plume rather than being ejected from the source in images taken in jupiter eclipse nonthermal visible wavelength emission was seen from individual volcanoes near io s sub jupiter and anti jupiter points near infrared emission from the brightest volcanoes indicates minimum magma temperatures in the 1150 to 1335 kelvin range consistent with basaltic composition

volcanic hot spots on io correlation with low albedo calderas comparison of voyager imaging data with voyager 1 infrared observations iris and with ground based telescopic infrared data demonstrates a strong correlation between hot spots and low albedo features reflectivity 0 3 in all visual wavelengths on io most of these low albedo areas occur on the floors of volcanic calderas and many are associated with active or recent volcanism we use this correlation to identify additional hot spots in regions not observed by iris and to model their temperatures the major features discovered by this method are in a ringlike structure in the south polar region centered at 140 w 75 s and amaterasu patera 307 w 38 n our model temperature for the south polar feature is 280 50 k taking account of the high latitudes of these features the estimated global average heat flow from the hot spots becomes 1 8 0 5 w m 2 most of this heat emanates from just a few very large hot spots the global distribution of hot spots is further evidence that io is a dimorphous body the hemisphere centered on 310 w 30 s is much more volcanically active than the opposite hemisphere the styles of heat transfer in io conductive versus convective may be related to the global distribution of hot spots large eruptive plumes and large scale topographic relief the correlation between hot spots and dark areas is due to 1 the absence of the bright materials such as so2 frost which cover most of the surface and 2 the presence of a low albedo substance spectral properties of the low albedo features extracted from the voyager multispectral data are consistent with a number of candidate materials liquid sulfur boiled sulfur silicate sulfur mixtures zinc sulfide fe sulfate and fe chloride quenched sulfur allotropes on the other hand are redder than the low albedo features on io and are incompatible with the elevated temperatures of the hot spots some of the dark caldera floor materials may be liquid sulfur and or thermally altered boiled sulfur liquid sulfur would tend to collect in the topographic depressions and fractured bedrock of the calderas and this would explain the concentration of low albedo material in the calderas the presence of liquid sulfur is also suggested by the hot spot temperature distribution typically 200 400 k and by morphologies suggestive of lava lakes however the liquid boiled sulfur model does not seem to work for babbar and amaterasu paterae and the evidence for liquid sulfur is not conclusive

time variability of io s volcanic activity from near ir adaptive optics observations on 100 nights in 2013 2015 abstract jupiter s moon io is a dynamic target exhibiting extreme and time variable volcanic activity powered by tidal forcing from jupiter we have conducted a campaign of high cadence observations of io with the goal of characterizing its volcanic activity between aug 2013 and the end of 2015 we imaged io on 100 nights in the near infrared with adaptive optics on the keck and gemini n telescopes which resolve emission from individual volcanic hot spots during our program we made over 400 detections of 48 distinct hot spots some of which were detected 30 times we use these observations to derive a timeline of global volcanic activity on io which exhibits wide variability from month to month the timelines of thermal activity at individual volcanic centers have geophysical implications and will permit future characterization by others we evaluate hot spot detection limits and give a simple parameterization of the minimum detectable intensity as a function of emission angle which can be applied to other analyses we detected three outburst eruptions in august 2013 but no other outburst scale events were observed in the subsequent 90 observations either the cluster of events in august 2013 was a rare occurrence or there is a mechanism causing large events to occur closely spaced in time we also detected large eruptions though not of outburst scale within days of one another at kurdalagon patera and sethlaus gabija paterae in 2015 as was also seen in the galileo dataset the hot spots we detected can be separated into two categories based on their thermal emission those that are persistently active for 1 year or more at moderate intensity and those that are only briefly active are time variable and often reach large intensities a small number of hot spots in the latter category appear and subside in a matter of days reaching particularly high intensities although these are not bright enough to qualify as outbursts their thermal signatures follow the same pattern suggesting that a similar mechanism may be responsible for these events though at a smaller scale two eruptions seen at kurdalagon patera in january and april 2015 occurred simultaneously with a brightening of the neutral cloud and plasma torus which are sourced from io s atmosphere a plume at kurdalagon patera such as was seen by new horizons in 2007 could have been responsible for the influx of material that caused these brightenings

the final galileo ssi observations of io orbits g28 i33 abstract we present the observations of io acquired by the solid state imaging ssi experiment during the galileo millennium mission gmm and the strategy we used to plan the exploration of io despite galileo s tight restrictions on data volume and downlink capability and several spacecraft and camera anomalies due to the intense radiation close to jupiter there were many successful ssi observations during gmm four giant high latitude plumes including the largest plume ever observed on io were documented over a period of eight months only faint evidence of such plumes had been seen since the voyager 2 encounter despite monitoring by galileo during the previous five years moreover the source of one of the plumes was tvashtar catena demonstrating that a single site can exhibit remarkably diverse eruption styles from a curtain of lava fountains to extensive surface flows and finally a 400 km high plume over a relatively short period of time 13 months between orbits i25 and g29 despite this substantial activity no evidence of any truly new volcanic center was seen during the six years of galileo observations the recent observations also revealed details of mass wasting processes acting on io slumping and landsliding dominate and occur in close proximity to each other demonstrating spatial variation in material properties over distances of several kilometers however despite the ubiquitous evidence for mass wasting the rate of volcanic resurfacing seems to dominate the floors of paterae in proximity to mountains are generally free of debris finally the highest resolution observations obtained during galileo s final encounters with io provided further evidence for a wide diversity of surface processes at work on io

io s active volcanoes during the new horizons era insights from new horizons imaging in february 2007 the new horizons spacecraft flew by the jupiter system obtaining images of io the most volcanically active body in the solar system the multicolor visible imaging camera mvic a four color visible to near infrared camera obtained 17 sets of images the long range reconnaissance imager lorri a high resolution panchromatic camera obtained 190 images including many of io eclipsed by jupiter we present a complete view of the discrete point like emission sources in all images obtained by these two instruments we located 54 emission sources and determined their brightnesses these observations the first that observed individual ionian volcanoes on short timescales of seconds to minutes demonstrate that the volcanoes have stable brightnesses on these timescales the active volcanoes tvashtar 63n 124w and e girru 22n 245w were observed by both lorri and mvic both in the near infrared nir and methane ch4 filters tvashtar was additionally observed in the red filter which allowed us to calculate a color temperature of approximately 1200 k we found that with some exceptions most of the volcanoes frequently active during the galileo era continued to be active during the new horizons flyby we found that none of the seven volcanoes observed by new horizons multiple times over short timescales showed substantial changes on the order of seconds and only one e girru exhibited substantial variation over minutes to days increasing by 25 in just over an hour and decreasing by a factor of 4 over 6 days observations of tvashtar are consistent with a current eruption similar to previously observed eruptions and are more consistent with the thermal emission of a lava flow than the fire fountains inferred from the november 1999 observations these data also present new puzzles regarding ionian volcanism since there is no associated surface change or low albedo feature that could be identified nearby the source of the emission from e girru is a mystery furthermore the in eclipse glows we observe over many paterae are likely to be gas emission from interaction with the magnetosphere but the details of that process are not clear

active volcanism on io as seen by galileo ssi abstract active volcanism on io has been monitored during the nominal galileo satellite tour from mid 1996 through late 1997 the solid state imaging ssi experiment was able to observe many manifestations of this active volcanism including 1 changes in the color and albedo of the surface 2 active airborne plumes and 3 glowing vents seen in eclipse about 30 large scale tens of kilometers surface changes are obvious from comparison of the ssi images to those acquired by voyager in 1979 these include new pyroclastic deposits of several colors bright and dark flows and caldera floor materials there have also been significant surface changes on io during the galileo mission itself such as a new 400 km diameter dark pyroclastic deposit around pillan patera while these surface changes are impressive the number of large scale changes observed in the four months between the voyager 1 and voyager 2 flybys in 1979 suggested that over 17 years the cumulative changes would have been much more impressive there are two reasons why this was not actually the case first it appears that the most widespread plume deposits are ephemeral and seem to disappear within a few years second it appears that a large fraction of the volcanic activity is confined to repeated resurfacing of dark calderas and flow fields that cover only a few percent of io s surface the plume monitoring has revealed 10 active plumes comparable to the 9 plumes observed by voyager one of these plumes was visible only in the first orbit and three became active in the later orbits only the prometheus plume has been consistently active and easy to detect observations of the pele plume have been particularly intriguing since it was detected only once by ssi despite repeated attempts but has been detected several times by the hubble space telescope at 255 nm pele s plume is much taller 460 km than during voyager 1 300 km and much fainter at visible wavelengths prometheus type plumes 50 150 km high long lived associated with high temperature hot spots may result from silicate lava flows or shallow intrusions interacting with near surface so2 a major and surprising result is that 30 of io s volcanic vents glow in the dark at the short wavelengths of ssi these are probably due to thermal emission from surfaces hotter than 700 k with most hotter than 1000 k well above the temperature of pure sulfur volcanism active silicate volcanism appears ubiquitous there are also widespread diffuse glows seen in eclipse related to the interaction of energetic particles with the atmosphere these diffuse glows are closely associated with the most active volcanic vents supporting suggestions that io s atmopshere is dominated by volcanic outgassing globally volcanic centers are rather evenly distributed however 14 of the 15 active plumes seen by voyager and or galileo are within 30 of the equator and there are concentrations of glows seen in eclipse at both the sub and antijovian points these patterns might be related to asthenospheric tidal heating or tidal stresses io will continue to be observed during the galileo europa mission which will climax with two close flybys of io in late 1999

ground based observations of time variability in multiple active volcanoes on io abstract since before the beginning of the galileo spacecraft s jupiter orbital tour we have observed io from the ground using nasa s infrared telescope facility irtf we obtained images of io in reflected sunlight and in eclipse at 2 3 3 5 and 4 8 m in addition we have measured the 3 5 m brightness of an eclipsed io as it is occulted by jupiter these lightcurves enable us to measure the brightness and one dimensional location of active volcanoes on the surface during the galileo era two volcanoes were observed to be regularly active loki and either kanehekili and or janus at least 12 other active volcanoes were observed for shorter periods of time including one distinguishable in images that include reflected sunlight these data can be used to compare volcano types and test volcano eruption models such as the lava lake model for loki

charting thermal emission variability at pele janus patera and kanehekili fluctus with the galileo nims io thermal emission database nited abstract using the nims io thermal emission database nited a collection of over 1000 measurements of radiant flux from io s volcanoes davies a g et al 2012 geophys res lett 39 l01201 doi 10 1029 2011gl049999 we have examined the variability of thermal emission from three of io s volcanoes pele janus patera and kanehekili fluctus at pele the 5 m thermal emission as derived from 28 night time observations is remarkably steady at 37 10 gw m 1 re affirming previous analyses that suggested that pele an active rapidly overturning silicate lava lake janus patera also exhibits relatively steady 5 m thermal emission 20 3 gw m 1 in the four observations where janus is resolved from nearby kanehekili fluctus janus patera might contain a pele like lava lake with an effusion rate qf of 40 70 m3 s 1 it should be a prime target for a future mission to io in order to obtain data to determine lava eruption temperature kanehekili fluctus has a thermal emission spectrum that is indicative of the emplacement of lava flows with insulated crusts effusion rate at kanehekili fluctus dropped by an order of magnitude from 95 m3 s 1 in mid 1997 to 4 m3 s 1 in late 2001

observations and temperatures of io s pele patera from cassini and galileo spacecraft images abstract pele has been the most intense high temperature hotspot on io to be continuously active during the galileo monitoring from 1996 2001 a suite of characteristics suggests that pele is an active lava lake inside a volcanic depression in 2000 2001 pele was observed by two spacecraft cassini and galileo the cassini observations revealed that pele is variable in activity over timescales of minutes typical of active lava lakes in hawaii and ethiopia these observations also revealed that the short wavelength thermal emission from pele decreases with rotation of io by a factor significantly greater than the cosine of the emission angle and that the color temperature becomes more variable and hotter at high emission angles this behavior suggests that a significant portion of the visible thermal emission from pele comes from lava fountains within a topographically confined lava body high spatial resolution nightside images from a galileo flyby in october 2001 revealed a large relatively cool

geologic mapping of the amirani gish bar region of io implications for the global geologic mapping of io abstract we produced the first geologic map of the amirani gish bar region of io the last of four regional maps generated from galileo mission data the amirani gish bar region has five primary types of geologic materials plains mountains patera floors flows and diffuse deposits the flows and patera floors are thought to be compositionally similar but are subdivided based on interpretations regarding their emplacement environments and mechanisms our mapping shows that volcanic activity in the amirani gish bar region is dominated by the amirani eruptive center aec now recognized to be part of an extensive combined amirani maui flow field a mappable flow connects amirani and maui suggesting that maui is fed from amirani such that the post voyager designation maui eruptive center should be revised amirani contains at least four hot spots detected by galileo and is the source of widespread bright sulfur flows and active dark silicate flows being emplaced in the promethean style slowly emplaced compound flow fields the floor of gish bar patera has been partially resurfaced by dark lava flows although other parts of its floor are bright and appeared unchanged during the galileo mission this suggests that the floor did not undergo complete resurfacing as a lava lake as proposed for other ionian paterae there are several other hot spots in the region that are the sources of both active dark flows confined within paterae and so2 and s2 rich diffuse deposits mapped diffuse deposits around fractures on mountains and in the plains appear to serve as the source for gas venting without the release of magma an association previously unrecognized in this region the six mountains mapped in this region exhibit various states of degradation in addition to gaining insight into this region of io all four maps are studied to assess the best methodology to use to produce a new global geologic map of io based on the newly released combined galileo voyager global mosaics to convey the complexity of ionian surface geology we find that a new global geologic map of io should include a map sheet displaying the global abundances and types of surface features as well as a complementary gis database as a means to catalog the record of surface changes observed since the voyager flybys and during the galileo mission

high temperature silicate volcanism on jupiter s moon io infrared wavelength observations of io by the galileo spacecraft show that at least 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on earth today in at least one case the eruption near pillan patera two independent instruments on galileo show that the lava temperature must have exceeded 1700 kelvin and may have reached 2000 kelvin the most likely explanation is that these lavas are ultramafic magnesium rich silicates and this idea is supported by the tentative identification of magnesium rich orthopyroxene in lava flows associated with these high temperature hot spots

io in the near infrared near infrared mapping spectrometer nims results from the galileo flybys in 1999 and 2000 galileo s near infrared mapping spectrometer nims observed io during the spacecraft s three flybys in october 1999 november 1999 and february 2000 the observations which are summarized here were used to map the detailed thermal structure of active volcanic regions and the surface distribution of so2 and to investigate the origin of a yet unidentified compound showing an absorption feature at 1 m we present a summary of the observations and results focusing on the distribution of thermal emission and of so2 deposits we find high eruption temperatures consistent with ultramafic volcanism at pele such temperatures may be present at other hot spots but the hottest areas may be too small for those temperatures to be detected at the spatial resolution of our observations loki is the site of frequent eruptions and the low thermal emission may represent lavas cooling on the caldera s surface or the cooling crust of a lava lake high resolution spectral observations of emakong caldera show thermal emission and so2 within the same pixels implying that patches of so2 frost and patches of cooling lavas or sulfur flows are present within a few kilometers from one another thermal maps of prometheus and amirani show that these two hot spots are characterized by long lava flows the thermal profiles of flows at both locations are consistent with insulated flows with the amirani flow field having more breakouts of fresh lava along its length prometheus and amirani each show a white ring at visible wavelengths while so2 distribution maps show that the highest concentration of so2 in both ring deposits lies outside the white portion visible measurements at high phase angles show that the white deposit around prometheus extends into the so2 ring this suggests that the deposits are thin and that compositional or grain size variations may occur in the radial direction so2 mapping of the chaac region shows that the interior of a caldera adjacent to chaac has almost pure so2 the deposit appears to be topographically controlled suggesting a possible origin by liquid flow

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

morphology temperature and eruption dynamics at pele abstract the pele region of io has been the site of vigorous volcanic activity from the time of the first voyager i observations in 1979 up through the final galileo ones in 2001 there is high temperature thermal emission from a visibly dark area that is thought to be a rapidly overturning lava lake and is also the source of a large sulfur rich plume we present a new analysis of voyager i visible wavelength images and galileo solid state imager ssi and near infrared mapping spectrometer nims thermal emission observations which better define the morphology of the region and the intensity of the emission the observations show remarkable correlations between the locations of the emission and the features seen in the voyager images which provide insight into eruption mechanisms and constrain the longevity of the activity we also analyze an additional wavelength channel of nims data 1 87 m which paradoxically because of reduced sensitivity allows us to estimate temperatures at the peak locations of emission measurements of eruption temperatures on io are crucial because they provide our best clues to the composition of the magma high color temperatures indicative of ultramafic composition have been reported for the pillan hot spot and possibly for pele although recent work has called into question the requirement for magma temperatures above those expected for ordinary basalts our new analysis of the pele emission near the peak of the hot spot shows color temperatures near the upper end of the basalt range during the i27 and i32 encounters in order to analyze the observed color temperatures we also present an analytical model for the thermal emission from fire fountains which should prove generally useful for analyzing similar data this is a modification of the lava flow emission model presented in howell howell r r 1997 icarus 127 394 407 adapted to the fire fountain cooling curves first discussed in keszthelyi et al keszthelyi l jaeger w milazzo m radebaugh j davies a g mitchell k l 2007 icarus 192 491 502 when applied to the i32 observations we obtain a fire fountain mass eruption rate of 5 1 10 5 kg s 1 for the main vent area and 1 4 10 4 kg s 1 for each of two smaller vent regions to the west these fire fountain rates suggest a solution to the puzzling lack of extensive lava flows in the pele region much of the erupted lava may be ejected at high speed into the fire fountains and plumes creating dispersed pyroclastic deposits rather than flows we compare gas and silicate mass eruption rates and discuss briefly the dynamics of this ejection model and the observational evidence

a photographic and acoustic transect across two deep water seafloor mounds mississippi canyon northern gulf of mexico in the northern gulf of mexico a series of seafloor mounds lie along the floor of the mississippi canyon in atwater valley lease blocks 13 and 14 the mounds one of which was drilled by the chevron joint industry project on methane hydrates in 2005 are interpreted to be vent related features that may contain significant accumulations of gas hydrate adjacent to gas and fluid migration pathways the mounds are located w150 km south of louisiana at w1300 m water depth new side scan sonar data multibeam bathymetry and near bottom photography along a 4 km northwest southeast transect crossing two of the mounds labeled d and f reveal the mounds detailed morphology and surficial characteristics mound d w250 m in diameter and 7 10 m in height has exposures of authigenic carbonates and appears to result from a seafloor vent of slow to moderate flux mound f which is w400 m in diameter and 10 15 m high is covered on its southwest flank by extruded mud flows a characteristic associated with moderate to rapid flux chemosynthetic communities visible on the bottom photographs are restricted to bacterial mats on both mounds and mussels at mound d no indications of surficial gas hydrates are evident on the bottom photographs published by elsevier ltd

thermal signature eruption style and eruption evolution at pele and pillan on io the galileo spacecraft has been periodically monitoring volcanic activity on io since june 1996 making it possible to chart the evolution of individual eruptions we present results of coanalysis of near infrared mapping spectrometer nims and solid state imaging ssi data of eruptions at pele and pillan especially from a particularly illuminating data set consisting of mutually constraining near simultaneous nims and ssi observations obtained during orbit c9 in june 1997 the observed thermal signature from each hot spot and the way in which the thermal signature changes with time tightly constrains the possible styles of eruption pele and pillan have very different eruption styles from september 1996 through may 1999 pele demonstrates an almost constant total thermal output with thermal emission spectra indicative of a long lived active lava lake the nims pillan data exhibit the thermal signature of a pillanian eruption style a large vigorous eruption with associated open channel or sheet flows producing an extensive flow field by orbit c10 in september 1997 the high mass eruption rate high liquidus temperature at least 1870 k eruption at pillan is the best candidate so far for an active ultramafic magnesium rich komatiitic flow on io a style of eruption never before witnessed the thermal output per unit area from pillan is however consistent with the emplacement of large open channel flows magma temperature at pele is 1600 k if the magma temperature is 1600 k it suggests a komatiitic basalt composition the power output from pele is indicative of a magma volumetric eruption rate of 250 to 340 m3 s 1 although the pele lava lake is considerably larger than its terrestrial counterparts the power and mass fluxes per unit area are similar to active terrestrial lava lakes