mass and heat flux of volcanic gas discharging from the summit crater of iwodake volcano satsuma iwojima japan during 1996 1999 abstract volcanic gas of iwodake has been discharged continuously from high temperature 900 c maximum fumaroles and a degassing vent which formed on the central floor of the summit crater after 1994 although most of the high temperature fumaroles located on the crater wall before 1991 many fumaroles appeared on the crater floor associated with the vent opening suggesting a shift of thermal activity from the peripheral to the central crater a large amount of volcanic gas has been discharged from the fumaroles and vent since heat has been transferred from ascending gas to the surrounding soil a region showing a surface temperature anomaly has developed around the fumaroles and vent to quantify iwodake thermal activity heat and volcanic gas mass fluxes were estimated during 1996 1999 using infrared thermal images and plume velocity and temperature data which were observed by a pitot tube and thermocouple the estimated gas mass flux was compared with the cospec data to investigate the accuracy of our estimation the gas mass flux had been decreased from 230 kg s in october 1996 to 30 kg s in november 1999 although the vent diameter had increased from 20 to 70 m during the same period this mass flux variation had indicated the decline of degassing rate the degassing depth was estimated from the volcanic gas mass flux and temperature the depth showed a tendency of magma head migration to shallower depth during 1996 1999 which was consistent with the drastic change of the surface manifestation

u pb dating of monazite and its application to geological problems monazite is an underutilized mineral in u pb geochronological studies of crustal rocks it occurs as an accessory mineral in a wide variety of rocks including granite pegmatite felsic volcanic a

thermal characterization of the vulcano fumarole field ground based thermal infrared surveys can contribute to complete heat budget inventories for fumarole fields however variations in atmospheric conditions plume condensation and mixed pixel effects can complicate vent area and temperature measurements analysis of vent temperature frequency distributions can be used however to characterise and quantify thermal regions within a field we examine this using four thermal infrared thermometer and thermal image surveys of the vulcano fossa fumarole field italy during june 2004 and july 2005 these surveys show that regions occupied by low temperature vents are characterised by distributions that are tightly clustered around the mean i e the standard deviation is low highly peaked positive kurtosis and skewed in the low temperature direction negative skewness this population is associated with wet fumaroles where boiling controls maximum temperature to cause a narrow distribution with a mode at 90 100 c in contrast high temperature vent regions have distributions that are widely spread about the mean i e the standard deviation is high relatively flat negative kurtosis and skewed in the high temperature direction positive skewness in this dry case fumaroles are water free so that maximum temperatures are not fixed by boiling as a result greater temperature variation is possible we use these results to define two vent types at vulcano on the basis of their thermal characteristics 1 concentrated localized regions of high temperature vents and 2 dispersed low temperature vents these occur within a much larger region of diffuse heat emission across which surfaces are heated by steam condensation the heat from which causes elevated surface temperatures for vulcano s lower fumarole zone high and low temperature vents occupied total areas of 3 and 6 m2 respectively and occurred within a larger 430 m2 vent free zone of diffuse heat emission for this lower zone we estimate that 21 43 103 w of heat was lost by diffuse heat emission a further 4 5 103 w was lost by radiation from high temperature vents and 6 5 103 w from low temperature vents thus radiative heat losses from high and low temperature vents within vulcano s lower fumarole zone respectively account for 10 and 15 of the total heat lost from this zone this shows that radiation from open vents can account for a non trivial portion of the total fumarole field heat budget

pre 2 8 ga crust in the opatica gneiss belt a potential source of detrital zircons in the abitibi and pontiac subprovinces superior province canada ages of detrital zircons in post 2 7 ga metasedimentary rocks of the southern abitibi and northern pontiac subprovinces require that pre 2 8 ga crust was exposed during or following deformation of the 2 70 and 2 68 ga and the belt forms a high grade crystalline core to a south vergent mountain belt along the northern margin of the abitibi subprovince erosion of the opatica and northern abitibi during thrusting would shed detritus southward in advance of a south vergent thrust system the lac rodayer complex may be the enigmatic source of 2 8 ga detrital zircons within turbidites of the southern abitibi and northern pontiac subprovinces

thermal monitoring of hydrothermal activity by permanent infrared automatic stations results obtained at solfatara di pozzuoli campi flegrei italy 1 a permanent automatic infrared ir station was installed at solfatara crater the most active zone of campi flegrei caldera after a positive in situ calibration of the ir camera we analyze 2175 thermal ir images of the same scene from 2004 to 2007 the scene includes a portion of the steam heated hot soils of solfatara the experiment was initiated to detect and quantify temperature changes of the shallow thermal structure of a quiescent volcano such as solfatara over long periods ambient temperature is the main parameter affecting ir temperatures while air humidity and rain control image quality a geometric correction of the images was necessary to remove the effects of slow movement of the camera after a suitable correction the images give a reliable and detailed picture of the temperature changes over the period october 2004 to january 2007 which suggests that origin of the changes were linked to anthropogenic activity vegetation growth and the increase of the flux of hydrothermal fluids in the area of the hottest fumaroles two positive temperature anomalies were registered after the occurrence of two seismic swarms which affected the hydrothermal system of solfatara in october 2005 and october 2006 it is worth noting that these signs were detected in a system characterized by a low level of activity with respect to systems affected by real volcanic crisis where more spectacular results will be expected results of the experiment show that this kind of monitoring system can be a suitable tool for volcanic surveillance

geochronological constraints on late archean magmatism deformation and gold quartz vein mineralization in the northwestern anialik river greenstone belt and igneous complex slave province n w t three phases of the anialik river igneous complex aric give u pb zircon ages in the range 2705 2683 ma and three units from the adjacent northwestern anialik river greenstone belt argb give ca 2678 ma ages titanite from unsheared aric rocks crystallized during localized metamorphism and deuteric alteration between 2693 and 2683 ma hydrothermal titanite in wall rocks to gold mineralized shear zones crystallized during early shear zone development 2670 1 ma and was subsequently locally altered to rutile with gold occurring within the rutile bearing assemblage unaltered second generation hydrothermal titanite overgrowing the rutile assemblage crystallized during later brittle ductile movement 2656 2 ma and provides a minimum age for gold mineralization relatively high 207pb 204pb ratios of pb in gold associated galena suggest that it was partly derived from significantly older crustal material possibly underlying the igneous complex and greenstone belt this interpretation is consisten

titanite rutile thermochronometry across the boundary between the archaean craton in karelia and the belomorian mobile belt eastern baltic shield abstract u pb isotopic dating has been carried out on titanites and rutiles from the karelian protocraton the belomorian mobile belt and the intervening junction zone these are some of the principal archaean crustal units in the baltic shield which have undergone regeneration to various degrees during the palaeoproterozoic palaeoproterozoic resetting of u pb titanite ages was complete in the belomorian belt and almost complete in the junction zone while it hardly affected the karelian protocraton in the latter major crustal cooling occurred at 2 71 2 69 ga after a major igneous event at 2 74 2 72 ga but a tectonothermal event at 2 65 2 64 ga was less comprehensive in the belomorian belt a northeastern marginal zone immediately underlying the collisional thrusting suture of the lapland kola orogen has somewhat higher titanite ages of ca 1 94 1 87 ga than the central zone where these ages range between 1 87 and 1 82 ga comparison between the titanite and rutile u pb ages suggests a postorogenic cooling rate between 2 and 4 ma in these parts of the belt the neoarchaean junction zone between the karelian and belomorian provinces was a zone of particularly intense tectonic magmatic and hydrothermal activity during or after the palaeoproterozoic lapland kola orogeny dominant newly grown titanites in that zone have ages as young as 1 78 1 75 ga and the age differences between the titanite and rutile u pb ages are substantially smaller than elsewhere

u pb dating of granites in the neoproterozoic sergipano belt ne brazil implications for the timing and duration of continental collision and extrusion tectonics in the borborema province abstract the sergipano belt is the outcome of collision between the pernambuco alagoas massif and the sao francisco craton during neoproterozoic assembly of west gondwana field relationships and u pb geochronology of granites intruded in garnet micaschists of the macurure domain are used to constrain the main collisional event d 2 in the belt the granites are divided into two groups the pre collisional granites pre to early d 2 and the syn collisional granites syn to tardi d 2 the latter were emplaced as sheets along the s 2 axial plane foliation or they were collected at the hinge zones of f 2 folds a u pb shrimp zircon age of 628 12 ma was obtained for the pre collisional camara tonalite two u pb tims titanite ages were obtained for the syn collisional granites 584 10 ma for the angico granite and 571 9 ma for the pedra furada granite and these ages are close to the garnet whole rock sm nd isochron of 570 ma found for the peak of metamorphism in the sergipano belt the ages of the camara tonalite 628 ma and the pedra furada granite 571 ma mark respectively the maximum age for beginning of the d 2 event and minimum age for the end in the macurure domain using these ages the main neoproterozoic d 2 collisional event has been in operation in the sergipano belt for at least 57 million years correlation with coeval granitoids farther north in the borborema province indicate that while in the sergipano belt the syn d 2 granites ca 590 570 ma were emplaced under compression in the borborema province they emplaced under extensional conditions related to regional strike slip shear zones these contrasting emplacement settings for contemporaneous neoproterozoic granitoids are explained by a combination of continent continent collision and extrusion tectonics

subsurface structure of the solfatara volcano campi flegrei caldera italy as deduced from joint seismic noise array volcanological and morphostructural analysis 1 the joint application of different seismological techniques for seismic noise analysis and the results of a volcanological and morphostructural survey have allowed us to obtain a detailed and well constrained image of the shallow crustal structure of the solfatara volcano campi flegrei caldera italy horizontal to vertical spectral ratios inversion of surface wave dispersion curves and polarization analysis provided resonance frequencies and peak amplitudes shear wave velocity profiles and polarization pattern of coherent ambient noise these results combined in a unique framework indicate that the volcanic edifice is characterized by lateral and vertical discontinuities and heterogeneities in terms of shear wave velocity lithological contrasts and structural setting the interpretation of the seismological results with the volcanological and morphostructural constraints supports the hypothesis that the volcano has been characterized by a complex and intense activity with the alternation of constructive and destructive phases during which magmatic and phreatomagmatic explosions built a complex tuff cone later reworked by atmospheric agents and altered by hydrothermal activity the differences in the velocity structure between the central and eastern parts of the crater have been interpreted as resulting from a possible eastward migration of the eruptive vent along the deformational features affecting the area and to the presence of viscous lava and lithified tuff bodies within the feeding conduits which are buried under a covering of reworked materials of variable thickness the observed fault and fracture systems partially inherited from regional structural setting and exhumed during volcanism and ground deformation episodes also seems to strongly control wave propagation affecting the noise polarization properties

coal petrology and coal seam gas contents of the walloon subgroup surat basin queensland australia abstract core exploration and appraisal drilling over the last four years have targeted the juandah upper and taroom lower coal measures of the middle jurassic walloon subgroup of the injune creek group these wells have shown that the high volatile bituminous perhydrous coals of the walloon subgroup have gas contents of between 1 and 14 m 3 t and some wells have encountered gas flows at rates of over 30 000 m 3 day this recent work has confirmed the initial supposition that the coals within the walloon subgroup contain sufficient quantities of gas to be economically viable as a coal seam gas source coal volumes depth and structure have also been confirmed from the initial work what has become apparent during this work is the variability in gas content across each of the seams in the juandah and taroom coal measures and the variability in coal petrographic composition of these two units are controlled by many factors what has also become apparent is that the taroom coal measures have a lower average gas content than the overlying juandah coal measures the obvious conclusion is that the difference in gas content is related to a difference in coal petrology not only do the gas contents of these coal intervals differ their gas adsorption capacities also differ with the taroom coal measures coals displaying on average lower gas content and lower gas adsorption capabilities again the obvious cause would be coal petrological differences but the juandah and taroom coal measures coals have similar maceral percentages an understanding of the relationship between gas desorption gas adsorption and coal composition is vital in determining which areas in the basin offers the most economically viable targets for the commercialisation of coal seam gas in the surat basin

hydrogeologic factors affecting gas content distribution in coal beds gas content in coal is not fixed but changes when equilibrium conditions within the reservoir are disrupted therefore gas content distribution in coal varies laterally within individual coal beds vertically among coal beds in a single well and within thicker coal beds major hydrogeologic factors affecting gas content variability include gas generation coal properties and reservoir conditions gas generation affects gas content variability on a regional scale whereas coal properties influence gas content distribution on a regional and local scale reservoir conditions affect gas content more locally within specific fields or individual wells the potential for high gas content is controlled directly by the amount of thermogenic and secondary biogenic gases generated from the coal which in turn are controlled by burial history maceral composition and basin hydrodynamics variability in mineral matter ash and moisture content sorption behavior among macerals diffusion coefficients and permeability result in heterogeneous gas content distribution gas content decreases with decreasing pressure and temperature and coal beds become undersaturated with respect to methane during basin uplift and cooling gas content generally increases where conventional and hydrodynamic trapping of coal gases occur and may decrease in areas of active recharge with downward flow potential and or convergent flow where there is no mechanism for entrapment

polyphase growth of accessory minerals during continental collision geochemical evidence from ultrahigh pressure metamorphic gneisses in the sulu orogen abstract an integrated study of petrology geochronology and geochemistry was performed for ultrahigh pressure metamorphic gneisses in the sulu orogen the results are used to elucidate the polyphase growth of such metamorphic minerals as zircon titanite and garnet in response to pressure temperature changes and fluid melt action during continental collision this provides insights into the property of metamorphic fluid melt and their effects on trace element mobility a combined result from ree patterns mineral inclusions and ti in zircon temperatures indicates three stages of zircon growth prograde growth occurred at 237 ma primarily at eclogite facies retrograde growth at 222 ma mostly at eclogite facies and the last growth at 205 ma at granulite facies the three stages of zircon growth are deciphered by distinct ree patterns and trace element compositions reflecting the differences in the property of metamorphic fluid melt the episodic growth of metamorphic zircon is primarily dictated by the episodic concentration of zr and si in metamorphic fluid melt relict domains of magmatic titanite are distinguished from metamorphosed and metamorphic domains by their distinctive ree patterns and trace element compositions the metamorphic titanite exhibit variably elevated nb contents and nb ta ratios suggesting nb ta fractionation due to breakdown of amphibole and or biotite during metamorphism polyphase growth of garnet is suggested by an integrated analysis of mineral inclusions and major and trace elements in large garnet grains trace element abundances vary in different zones of garnet which is ascribed to changes in the paragenesis and composition of matrix minerals involved in garnet forming reactions at different p t conditions therefore the metamorphic growth of zircon titanite and garnet would have occurred not only during prograde subduction but also during retrograde exhumation in the continental collision zones both metamorphic dehydration and partial melting would have taken place episodically during the collisional orogeny the breakdown of hydrous minerals at high to ultrahigh pressure conditions is a key to fluid liberation and element supply for the growth of these accessory minerals

timing of anatexis in the eastern adirondack highlands implications for tectonic evolution during ca 1050 ma ottawan orogenesis u pb sensitive high resolution ion microprobe shrimp analyses of zircons from migmatitic metapelites in the eastern adirondack highlands demonstrate that substantial anatexis took place ca 1050 ma during the late but still high grade ca 1090 1050 ma ottawan orogeny these results contrast with data from metapelites of the southwestern adirondack highlands and adirondack lowlands which indicate that anatexis occurred ca 1200 1160 ma during the shawinigan orogeny and subsequent ca 1155 ma anorthosite mangerite charnockite granite amcg magmatism ca 1180 1150 ma zircons from this western regime do not contain ca 1050 ma ottawan metamorphic overgrowths the absence of ca 1050 ma ottawan anatexis and overgrowths in the adirondack lowlands is explained by the observation that consistent with titanite cooling ages post 1150 ma temperatures did not exceed 700 c in the southwestern adirondack highlands the absence of ca 1050 ma anatexis can be accounted for by earlier dehydration of metapelites during ca 1180 1150 ma shawinigan amcg metamorphism the occurrence of ca 1050 ma anatexis and formation of metamorphic zircons in the eastern adirondacks cannot be explained by higher temperatures because geothermometry indicates that all of the adirondack highlands reached a nearly uniform 750 800 c during this period accordingly the occurrence of ca 1050 ma ottawan anatexis in the eastern regime is interpreted to be the result of 1 infl uxes of hydrous fl uids at ca 1050 ma or 2 decompression melting during late extensional exhumation a recently recognized low angle late ottawan ca 1050 ma fault system may have provided both fl uid conduits and footwall decompression the sense of displacement along the shear zone has not yet been unequivocally determined but preliminary investigations of kinematic indicators demonstrate normal displacement thus this structure may be an analogue of the ca 1050 ma northwest dipping carthage colton zone normal fault system that juxtaposed the adirondack lowlands against the adirondack highlands in this context these fault zones form a quasi symmetrical core complex or gneiss dome within which the high grade core of the adirondack highlands was tectonically exhumed a similar east dipping along strike normal fault in quebec tawachiche shear zone exhumed the eastern morin and lac taureau terranes at ca 1050 ma and may merge with the eastern adirondack shear zone described here

coal reservoir characteristics and coalbed methane resource assessment in huainan and huaibei coalfields southern north china abstract the huaibei and huainan coalfields in southern north china contain abundant coalbed methane cbm resources 1 1 10 12 m 3 net accumulated thicknesses of all minable coal seams are 18 32 m in huainan and 8 18 m in huaibei coalfields coal rank in the huainan coalfield high volatile a and b bituminous r o 0 65 0 85 is generally controlled by geothermal metamorphism in comparison coal rank in the huaibei coalfield varies from high volatile a bituminous to semi anthracites 0 8 to 2 8 r o and is controlled by the influence of the cretaceous yanshanian magmatic metamorphism in both coalfields coal reservoirs have low permeability values of 0 0013 0 224 md and porosity of 0 9 10 9 pores in coals are dominated by those with diameter 2 in both coalfields the abundance of microfractures in coals is related to the coal structures commonly more abundant in sheared coals 200 per 9 cm 2 than in the normally structured coals 2 the in place gas content is generally 8 16 m 3 t in huaibei and 10 30 m 3 t in huainan coalfields these data yield an estimated in place cbm resource of 375 247 10 9 m 3 for the huaibei and 722 677 10 9 m 3 for the huainan coalfields based on the cbm resource investigation and reservoir evaluation the most prospective target areas for cbm production are evaluated which include the nanping taoyuan mines of the southern suxian deep coal district and zhuxianzhuang and luling mines in eastern suxian area of the huaibei coalfield and the area around the panji 2 mine in panji xieqiao coal mining districts in the huainan coalfield

satellite derived surface temperature and in situ measurement at solfatara of pozzuoli naples italy ground thermal anomalies in volcanic hydrothermal systems where the outflow of hot fluids gives rise to fumarolic fields soil degassing and hot soils have up to now rarely been investigated by using satellite here we report a comparison between surface temperature derived by satellite data and a large data set of measured soil temperatures and co2 fluxes for a volcanic hydrothermal system the solfatara of pozzuoli campi flegrei italy surface temperatures derived from aster advanced spaceborne thermal emission and reflection radiometer data are compared with soil temperatures and co2 fluxes from four surveys performed in 2003 2010 and in 2014 the good match between the spatial distributions of computed and measured temperatures suggests the adequacy of satellite data to describe the solfatara thermal anomaly while the correspondence between temperatures and co2 fluxes evidences the link between degassing and heating processes the aster derived surface temperatures 14 37 c are coherent with those measured in the soil 10 97 c at 10 cm depth considering the effect of the thermal gradients which characterize the degassing area of solfatara this study shows that satellite data can be a very powerful tool with which to study surface thermal anomalies and can provide a supplementary tool to monitor thermal evolution of restless volcanoes

interpreting titanite u pb dates and zr thermobarometry in high grade rocks empirical constraints on elemental diffusivities of pb al fe zr nb and ce length scales of compositional heterogeneity in titanite from 750 to 1000 c metamorphic rocks from southern madagascar were measured to provide empirical constraints on elemental diffusivities the calculated pb diffusivity is comparable to experimental estimates of sr diffusivity because of this u pb dates from rocks that reached peak temperatures 900 c thus zr in titanite thermobarometry should not be reset by diffusion in all but the smallest grains in the hottest rocks al and nb diffuse at similar rates to zr ce and fe diffuse slower than pb but faster than zr differences in empirical and experimental estimates of elemental diffusivities might be related to the complexity of most natural titanite solid solutions compared to the near end member titanite used in experiments

evaluation of geological features for deep coalbed methane reservoirs in the dacheng salient jizhong depression china abstract the dacheng salient of the northeast jizhong depression is one of the most promising areas for deep coalbed methane cbm development in china this work investigates the permo carboniferous c p taiyuan and shanxi formation coals and cbm geology and gas accumulation characteristics in the dacheng salient based on field data from 24 wells and laboratory measurements of eight coal samples and eight mudstone and sandstones from exploration well d1 1 the results show that the coal rank in the dacheng salient is a high volatile c bituminous coal to low volatile bituminous coal 0 54 1 85 r o controlled by the magmatism in the region the coals vary from 2 94 to 8 58 in porosity and 0 263 m 2 g to 2 6 m 2 g in bet surface area the in situ permeability is low normally less than 0 5 10 3 m 2 methane isothermal adsorption measurements of five coal samples reveal that their maximum adsorption capacity on an as received basis varies from 17 13 to 25 98 m 3 t with an apparent relationship with ash yield the roof and floor of coal seams are mainly mudstone with minor quantities of sandy mudstone and carbonate all have the ability to be suitable cap rocks with adequate sealing capacity and large breakthrough pressure the in place gas content range from 10 23 to 1 41 m 3 t with a decreasing trend from no 3 to no 6 coal seam group in the d1 1 well due to effects by the active ground water near the east jinghai dacheng fault however the gas content and the gas saturation increase with burial depth and ground water salinity and decrease with coal rank finally based on a comprehensive analysis of coal thickness gas content hydrogeology conditions roof floor and depth properties this study reveals that the best prospective target areas for cbm production are the south central parts of the dacheng salient at1200 1600 m in depth

possible controls of hydrogeological and stress regimes on the producibility of coalbed methane in upper cretaceous tertiary strata of the alberta basin canada the coalbed methane potential and producibility of any coal bearing strata are strongly affected by the hydrogeological regime of formation waters and by coal permeability which in turn depends on the effective stress regime of the coals peat that accumulated in the alberta basin during the late cretaceous and early tertiary led to the formation of coal deposits that may contain significant coalbed methane resources the flow of formation waters plays an important role in the maintenance and producibility of this resource the present day flow is driven by gravity topography and erosional rebound and is controlled by rock permeability and the presence of gas saturated sandstones the estimated gas in place in the tertiary upper cretaceous coals decreases significantly with stratigraphic age ranging between less than 2 bcf mi2 in the lower coal zones and 12 bcf mi2 in the uppermost coals the gas content especially of the deeper coals is lower than would be expected for the corresponding coal rank and burial depth most likely because the underpressuring has caused the release of gas from the coals and accumulation in adjacent sands the shallow coals although of low rank may contain important amounts of late stage biogenic methane the salinity of formation water in shallow coal seams where the flow is driven by topography is low generally less than 1500 mg l although in places it reaches 3000 5000 mg l the salinity of formation water in the deeper underpressured strata in the west central part of the basin is significantly higher reaching 18 000 mg l this affects treatment and or disposal strategies with regard to the water produced concurrent to coalbed methane the producibility of this resource depends on coal permeability which decreases west southwestward with increasing burial depth from the order of several darcys in the shallow zones to millidarcys in the deep zones the minimum effective stress which affects coal permeability by closing fractures increases west southwestward from zero at the erosional edge of these strata to approximately 20 mpa near the rocky mountain deformation front fractures including those in coal seams will generally be vertical and will propagate on a southwest northeast axis along the direction of the maximum horizontal stress in a direction generally perpendicular to the rocky mountain deformation front considering the hydrogeological and stress regimes in conjunction with estimations of the gas content in coals the region with probably good coalbed methane potential and producibility are the ardley coal zone in the scollard formation and maybe to a lesser extent the coal zones of the stratigraphically deeper edmonton and belly river groups along their respective subcrop in central and southern alberta the deep edmonton and belly river strata in western and central alberta have most likely a reduced coalbed methane potential as a result of lower gas content and of low permeability these regional considerations need to be applied against local studies of coal thickness rank permeability and gas content to identify the best targets for coalbed methane exploration and production

geological controls on coalbed methane reservoir capacity and gas content the influence of coal composition and rank on coalbed methane reservoir capacity gas content and gas saturation have been investigated for a series of australian canadian and united states coals globally there is no or little correlation between coal rank and methane adsorption capacity as commonly assumed although in particular basins there are general trends with rank and composition micropore1 capacity and surface area determined from low pressure carbon dioxide adsorption isotherms 0 c decrease and then increase with rank passing through a minimum in the high volatile bituminous coal rank there is no consistent variation in modal micropore size or size distribution with rank for suites of isorank coals there is a poor permian bulli and wongawilli seams australia to good positive correlation gates formation coal seams lower cretaceous canada between vitrinite content and methane adsorption capacity dry ash free and as received bases for each isorank coal suite there is a good correlation between micropore capacity and abundance of vitrinite and high pressure methane adsorption capacity comparison of coals of similar composition but from different isorank suites indicates however that the coals with the highest methane adsorption capacity do not necessarily have the highest micropore capacity such results are counterintuitive most pore volume available for methane adsorption is generally assumed to be microporosity it is suspected that moisture prevents methane from accessing some microporosity or competes with methane for adsorption space carbon dioxide micropore capacity which is performed on a dry basis may thus not reflect the microporosity available for gas adsorption in moisture equilibrated coals alternatively because of differing physical and chemical properties of carbon dioxide and methane apparent microporosity available to carbon dioxide due to greater energy of adsorption may not be available to methane total desorbed gas from canister analyses of sydney basin australian coals suggests that most coals are under saturated for a small data set the degree of saturation is negatively correlated with permeability r 0 78 suggesting preferential gas leakage from the higher permeability coals which are vitrite rich some degree of under saturation is probably the result of increased reservoir capacity as a consequence of uplift of the coal seams and thus lower temperatures following gas generation rates of desorption are correlated with total gas content r 0 79 but do not correlate with rank or any compositional parameter

heat flux measurement from thermal infrared imagery in low flux fumarolic zones example of the ty fault la soufriere de guadeloupe monitoring the geothermal flux of a dormant volcano is necessary both for hazard assessment and for studying hydrothermal systems heat from a magma body located at depth is transported by steam to the surface where it is expelled in fumaroles if the heat flow exceeds 500 w m2 if the heat flow is lower than 500 w m2 steam mainly condensates in the soil close to surface and produces a thermal anomaly detectable at the surface in this study we propose a method to quantify low heat fluxes from temperature anomalies measured at the surface by a thermal infrared camera once corrected from the atmospheric and surface effects thermal infrared images are used to compute 1 the excess of radiative flux 2 the excess of sensible flux and 3 the steam flux from the soil to the atmosphere these calculations require measurements of atmospheric parameters temperature wind velocity and humidity and estimations of surface parameters roughness and emissivity this method has been tested on a low flux fumarolic zone of the soufriere volcano guadeloupe island lesser antilles and compared to a flux estimation realized from the thermal gradient measurements into the soil the two methods show a good agreement and a similar precision 267 46 w m2 for the thermal infrared method and 275 50 w m2 for the vertical temperature gradient method if surface roughness is well calibrated

methanogenic pathways of coal bed gas in the powder river basin united states the geologic factor abstract coal bed gas of the tertiary fort union and wasatch formations in the powder river basin in wyoming and montana u s was interpreted as microbial in origin by previous studies based on limited data on the gas and water composition and isotopes associated with the coal beds to fully evaluate the microbial origin of the gas and mechanisms of methane generation additional data for 165 gas and water samples from 7 different coal bed methane bearing coal bed reservoirs were collected basinwide and correlated to the coal geology and stratigraphy the c1 c2 c3 ratio and vitrinite reflectance of coal and organic shale permitted differentiation between microbial gas and transitional thermogenic gas in the central part of the basin analyses of methane 13c and d carbon dioxide 13c and water d values indicate gas was generated primarily from microbial co2 reduction but with significant gas generated by microbial methyl type fermentation aceticlastic in some areas of the basin microbial co2 reduction occurs basinwide but is generally dominant in paleocene fort union formation coals in the central part of the basin whereas microbial methyl type fermentation is common along the northwest and east margins isotopically light methane 13c is distributed along the basin margins where d is also depleted indicating that both co2 reduction and methyl type fermentation pathways played major roles in gas generation but gas from the latter pathway overprinted gas from the former pathway more specifically along the northwest basin margin gas generation by methyl type fermentation may have been stimulated by late stage infiltration of groundwater recharge from clinker areas which flowed through highly fractured and faulted coal aquifers also groundwater recharge controlled a change in gas composition in the shallow eocene wasatch formation with the increase of nitrogen and decrease of methane composition of the coal bed gas other geologic factors such as burial thermal and maturation history lateral and vertical continuity and coalification of the coal beds also played a significant role in controlling methanogenic pathways and provided new perspectives on gas evolution and emplacement the early stage gas produced by co2 reduction has mixed with transitional thermogenic gas in the deeper central parts of the powder river basin to form old gas whereas along the basin margins the overprint of gas from methyl type fermentation represents new gas thus a clear understanding of these geologic factors is necessary to relate the microbiological biogeochemical and hydrological processes involved in the generation of coal bed gas

anatomy of an early archean gneiss complex 3900 to 3600 ma crustal evolution in southern west greenland the early archean complex of southern west greenland consists of polyphase tonalitic trondhjemitic granodioritic ttg and granitic amitsoq gneisses with inclusions of volcanic and sedimentary rocks gabbros and ultramafic rocks in this complex rocks of similar appearance and composition were found to be of different ages by u pb zircon dating the amitsoq gneisses comprise 3870 3820 3810 3760 3730 3700 and 3625 ma ttg and 3660 3650 and 3625 ma granites and their inclusions belong to several supracrustal sequences with a similar spread of ages these results show that the complex grew by episodic addition of new ttg and welding together of rocks of different ages a possible plate tectonics scenario is as follows melting of subducted mafic oceanic crust formed 3700 ma microcontinents consisting of ttg suites with predominantly mafic inclusions at 3650 ma collision between microcontinents caused crustal thickening high grade metamorphism and emplacement of leucogranites at 3625 ma subduction at the edge of the 3625 ma continental mass created a new crustal addition comprising both ttg and granite while granites were emplaced into the 3625 ma continental mass

archean gold mineralization in the wabigoon subprovince a product of crustal accretion evidence from u pb geochronology in the lake of the woods area superior province canada within the lake of the woods greenstone terrain in the wabigoon subprovince of northwest ontario gold is in faults shears and tension veins that developed in response to a late archean northwest directed contraction and emplacement of contemporaneous plutons nine rocks in this area have been dated using u pb analyses of zircon in order to obtain precise time constraints on gold mineralization and to compare its timing with the age of major crustal events in the region a mineralized dike at the duport mine shoal lake is 2716 pm 2 ma old whereas a later dike that cuts mineralized rocks has an age of 2709 pm 2 ma gold mineralization is therefore distinctly younger than calc alkaline and tholeiitic rocks dated at 2724 pm 2 ma in the shoal lake area and 2727 pm 2 ma in the high lake area to the north hydrothermal activity associated with mineralization at the duport mine overprints the amphibolite facies contact metamorphic aureole of the snowshoe bay batholith 2708 pm 7 ma

variations in pore characteristics in high volatile bituminous coals implications for coal bed gas content abstract the seelyville coal member of the linton formation pennsylvanian in indiana was studied to 1 understand variations in pore characteristics within a coal seam at a single location and compare these variations with changes occurring between the same coal at different locations 2 elaborate on the influence of mineral matter and maceral composition on mesopore and micropore characteristics and 3 discuss implications of these variations for coal bed gas content the coal is high volatile bituminous rank with r 0 ranging from 0 57 to 0 60 bet specific surface areas determined by nitrogen adsorption of the coals samples studied range from 1 8 to 22 9 m 2 g bjh adsorption mesopore volumes from 0 0041 to 0 0339 cm 3 g and micropore volumes determined by carbon dioxide adsorption from 0 0315 to 0 0540 cm 3 g the coals that had the largest specific surface areas and largest mesopore volumes occur at the shallowest depths whereas the smallest values for these two parameters occur in the deepest coals micropore volumes in contrast are not depth dependent in the coal samples examined for this study mineral matter content influenced both specific surface area as well as mesopore and micropore volumes it is especially clear in the case of micropores where an increase in mineral matter content parallels the decrease of micropore volume of the coal no obvious relationships were observed between the total vitrinite content and pore characteristics but after splitting vitrinite into individual macerals we see that collotelinite influences both meso and micropore volume positively whereas collodetrinite contributes to the reduction of mesopore and micropore volumes there are large variations in gas content within a single coal at a single location because of this variability the entire thickness of the coal must be desorbed in order to determine gas content reliably and to accurately calculate the level of gas saturation

u pb geochronology of zircon and polygenetic titanite from the glastonbury complex connecticut usa an integrated sem empa tims and shrimp study abstract u pb ages for zircon and titanite from a granodioritic gneiss in the glastonbury complex connecticut have been determined using both isotope dilution thermal ionization mass spectrometry tims and the sensitive high resolution ion microprobe shrimp zircons occur in three morphologic populations 1 equant to stubby multifaceted colorless 2 prismatic dark brown with numerous cracks and 3 elongate prismatic light tan to colorless cathodoluminescence cl imaging of the three populations shows simple concentric oscillatory zoning the zircon tims age weighted average of 207pb 206pb ages from group 3 grains 450 5 1 6 ma mswd 1 11 and shrimp age composite of 206pb 238 u age data from all three groups 448 2 2 7 ma mswd 1 3 are interpreted to suggest a relatively simple crystallization history titanite from the granodioritic gneiss occurs as both brown and colorless varieties scanning electron microscope backscatter bse images of brown grains show multiple cross cutting oscillatory zones of variable brightness and dark overgrowths colorless grains are unzoned or contain subtle wispy or very faint oscillatory zoning electron microprobe analysis empa clearly distinguishes the two populations brown grains contain relatively high concentrations of fe2o3 ce2o3 up to 1 5 wt nb2o5 and zr cerium concentration is positively correlated with total ree y concentration which together can exceed 3 5 wt oscillatory zoning in brown titanite is correlated with variations in ree concentrations in contrast colorless titanite both as discrete grains and overgrowths on brown titanite contains lower concentrations of y ree fe2o3 and zr but somewhat higher al2o3 and nb2o5 uranium concentrations and th u discriminate between brown grains typically 200 400 ppm u all analyses but one have th u between about 0 8 and 2 and colorless grains 10 60 ppm u th u of 0 0 17 in contrast to the zircon u pb age results shrimp u pb data from titanite indicate multiple growth episodes in brown grains oscillatory zoned cores formed at 443 6 ma whereas white in bse cross cutting zones are 425 9 ma colorless grains and overgrowths on brown grains yield an age of 265 8 ma using the total pb method or 265 5 ma using the weighted average of the 206pb 238u ages however empa chemical data identify zoning that suggests that this colorless titanite may preserve three growth events oscillatory zoned portions of brown titanite grains are igneous in origin white cross cutting zones probably formed during a previously unrecognized event that caused partial dissolution of earlier titanite and reprecipitation of a slightly younger generation of brown titanite colorless titanite replaced and grew over the magmatic titanite during the permian alleghanian orogeny these isotopic data indicate that titanite like zircon can contain multiple age components coupling shrimp microanalysis with empa and sem results on dated zones as presented in this study is an efficient and effective technique to extract additional chronologic data to reveal the complexities of igneous crystallization and metamorphic growth

effects of a volcanic plume on thermal imaging data ground based thermal imaging is becoming an increasingly important tool for volcano surveillance however the impact of volcanic plumes on quantitative measurements of surface temperature has not been previously evaluated here we use a radiative transfer model to simulate gas primarily h2o and so2 and aerosol absorptions over the path between a thermal camera and a heat source on stromboli volcano italy a ftir spectrometer was used to quantify path amounts of gases likely to be encountered when making thermal measurements of the active craters we find that when using a camera sensitive from 7 5 to 13 mu m underestimates of similar to 400 k may be produced when viewing a source with an actual temperature of 1200 k cameras that operate between 3 and 5 mu m are somewhat less susceptible to these errors

seismicity associated with the 2004 2006 renewed ground uplift at campi flegrei caldera italy abstract following the significant ground uplift 1 8 m of the 1982 1984 bradyseismic crisis the recent history of campi flegrei volcanic complex italy has been dominated by a subsidence phase recent geodetic data demonstrate that the subsidence has terminated and that positive ground deformation renewed in november 2004 at a low but accelerating rate leading to about 4 cm of uplift by the end of october 2006 as in previous episodes ground uplift has been accompanied by swarms of micro earthquakes m 1 4 in three distinct episodes october 2005 october 2006 and december 2006 hypocenters of these earthquakes are mainly located beneath the solfatara volcano at depths ranging between 0 5 and 4 km inversion of s wave spectra indicates source radius and stress drop on the order of 30 60 m and 104 9 105 pa respectively fault plane solutions indicate predominantly normal mechanisms accompanying the october 2006 swarm we detected intense long period lp activity for about 1 week these signals consist of weak monochromatic oscillations whose spectra exhibit a main peak at frequency 0 8 hz this peak is common to all the stations of the network and not present in the noise spectra suggesting that it is a source effect about 75 of the detected lps cluster into three groups of mutually similar events adjustment of waveforms using cross correlation allows for precise alignment and stacking which enhances signal onsets and permits accurate absolute arrival picks and thus better absolute as well as relative locations locations associated with the three different clusters are very similar and appear to delineate the se rim of the solfatara volcano at a depth of about 500 m the most likely source process for the lp events involves the resonance of a fluid filled buried cavity quality factors of the resonator cluster in a narrow interval around 4 which is consistent with the vibration of a buried cavity filled with a water vapour mixture at poor gas volume fractions we propose a conceptual model to interpret the temporal and spatial patterns of the observed seismicity

inherited pb components in magmatic titanite and their consequence for the interpretation of upb ages abstract the occurrence of inherited radiogenic pb components in 35 ma old magmatic titanite is reported here for the first time the about 810 ma age of the inherited components is identical to that contained in zircon from the same amphibole bearing syenite sample in both minerals the precambrian components were not totally reset during magmatic new growth at 35 ma this age pattern substantiates that the u pb chronometer in titanite is resistant to temperatures in excess of 712 c as is already known for zircon and monazite in consequence u pb ages from crystalline titanites have to be interpreted as the age of mineral formation or re crystallization rather than the time of u pb system closure during cooling of the rock

protoliths and petrogenesis of archean gneisses from the kenora area english river subprovince northwest ontario abstract archean gneissic rocks in the kenora area can be divided into three groups 1 1 remnants of a dominantly mafic supracrustal sequence 2 2 biotite tonalite gneisses 3 3 granitic pegmatoid gneisses from field petrographic and compositional data the biotite tonalite gneisses are interpreted as plutonic rocks derived by partial melting of the supracrustal sequence the granitic pegmatoid gneisses are considered to be the product of fractional crystallization of the tonalitic magma attempts were made to reconstruct this scheme by computer assisted trace element modelling using rees with the source rock constrained to one having a bulk composition similar to that of the fine grained amphibolites within the supracrustal sequence comparable to archean tholeiite elsewhere the most satisfactory source rock was found to be a two pyroxene garnet granulite quartz 5 plagioclase 25 35 clinopyroxene 30 40 orthopyroxene 15 25 garnet 5 15 this when 10 melted under equilibrium non modal conditions will yield a model melt with a ree pattern similar to that observed in the tonalites quartz eclogite granulite without garnet and amphibolite are not acceptable source rocks under the modelling conditions used the mineralogy of the optimum model source rock is similar to that expected in a quartz tholeiite melting between 45 and 50 km depth the granitic pegmatoid gneisses have very low ree content especially lrees and their patterns defied conventional modelling they may result from ree loss in residual fluids or the end result after precipitation of ree rich phases such as allanite

heat flow in vapor dominated areas of the yellowstone plateau volcanic field implications for the thermal budget of the yellowstone caldera the yellowstone caldera the 0 11 km 2 obsidian pool thermal area opta and the 0 25 km 2 solfatara plateau thermal area spta conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at 600 locations and from laboratory measurements of soil properties the conductive heat output is 3 6 0 4 mw and 7 5 0 4 mw from the opta and the spta respectively the advective heat output from soils is 1 3 0 3 mw and 1 2 0 3 mw from the opta and the spta respectively and the heat output from thermal pools in the opta is 6 8 1 4 mw these estimates result in a total heat output of 11 8 1 4 mw and 8 8 0 4 mw from opta and spta respectively focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor

factors affecting the accuracy of thermal imaging cameras in volcanology volcano observatories and researchers are recognizing the potential usefulness of thermal imaging cameras both before and during volcanic eruptions obvious applications include measurements of the surface temperatures of active lava domes and lava flows to determine the location of the most active parts of these potentially hazardous features if appropriate precautions are taken the new generation of thermal imaging cameras can be used to extract quantitative as well as qualitative information on volcanic activity for example they can be used to measure the temperature of lava on eruption and to reveal how the crust cools during flow emplacement this is important for the validation of lava flow models to ensure that meaningful temperatures are collected thermal imaging data must be corrected for instrumental errors emissivity of the surface being imaged atmospheric attenuation viewing angle and surface roughness controlled laboratory experiments have been undertaken to determine the emissivity of smooth and rough samples and the effects of viewing angle and to quantify the errors measured emissivities range from 0 973 0 002 for smooth samples of basalt and 0 984 0 004 for rough samples errors in emissivity corrected temperatures are within 15 c for lava at 1100 c variations from individual sensor receptors which provide individual pixel temperature data were found to be 0 6 and instrumental errors of the cameras used were 0 1 apparent temperatures were found to vary by less than the instrumental error for viewing angles up to 30 degrees from normal to lava and thereafter increased by 1 c per degree by increasing the apparent viewing distance of a small vent on mount etna from 1 5 to 30 m the maximum temperature is shown to decrease by 53 c due to integrated averaging of radiance over increased pixel areas at a viewing distance of 250 m the maximum temperature decreased by 200 c with a further 75 c decrease due to atmospheric attenuation for a relative humidity of 50 however errors in relative humidity measurements can lead to atmospheric attenuation correction inaccuracies up to 200 c at viewing distances of 1 km we show how temperatures measured using thermal imaging cameras can be corrected to give improved estimates of temperature distributions on the surface of active lava flows

titanite petrochronology linked to phase equilibrium modelling constrains tectono thermal events in the akia terrane west greenland abstract the mesoarchean akia terrane in west greenland contains a detailed magmatic and metamorphic mineral growth record from 3 2 ga to at least c 2 5 ga this time span makes this region an important case study in the quest to track secular changes in geodynamic style which may ultimately inform on the development of plate tectonics as a globally linked system of lateral rigid plate motions the common accessory mineral titanite has recently become recognised as a powerful high temperature geochronometer whose chemistry may chart the thermal conditions of its growth furthermore titanite offers the potential to record the time temperature history of mafic lithologies which may lack zircon although titanite suffers from higher levels of common pb than many other u pb chronometers we show how measurement of 207pb 206pb in texturally coeval biotite may assist in the characterization of the appropriate common pb composition in titanite titanite extracted from two samples of mafic gneisses from the akia terrane both yield u pb ages of c 2 54 ga although coeval their chemistry implies growth under two distinctly different processes in one case the titanite has elevated total ree high th u and grew from an in situ partial melt consistent with an identical date to granite dyke zircon in contrast the second titanite sample contains greater common pb lower total ree lower th u and grew from dominantly hydrothermal fluids zr in titanite thermometry for partial melt derived titanite with activities constrained by phase equilibrium modelling indicates maxima of c 690 c elsewhere in the akia terrane coeval metamorphism linked to growth of hydrothermal titanite is estimated at temperatures of c 670 c these new results when coupled with existing findings indicate punctuated repeated metamorphic events in the akia terrane in which high temperature conditions re occurred at least three times between 3 0 and 2 5 ga but crucially changed in style across a c 3 0 ga change point we interpret this change in metamorphism as reflecting a fundamental shift in geodynamic style in west greenland at 3 0 ga consistent with other estimates for the onset of widespread plate tectonic type processes

hydrodynamic and stratigraphic controls for a large coalbed methane accumulation in ferron coals of east central utah abstract upper cretaceous coals within the ferron sandstone member of the mancos shale contain large volumes of coalbed methane coals at the northern end of the 80 mile long 129 km ferron trend have produced more than 200 billion cubic feet bcf 5663 10 6 m 3 of coalbed methane with daily production of 260 million cubic feet per day mmcfd 7 36 10 6 m 3 day from 470 wells during november 2000 core data from exploratory wells drilled along trend to the south indicate that the gas content of the coals decreases dramatically from north to south even though the rank and maturity of the coals decreases only slightly the area with lowest gas content correlates with the outcrop of the ferron coals hydrodynamic studies have shown that the ferron coals are aquifers that are recharged from the wasatch plateau to the west regional mapping indicates that the productive fields are large stratigraphic traps where the coals pinchout updip into tight marine shales to the east much of the produced gas is secondary biogenic gas and migrated thermogenic gas that has moved from the wasatch plateau and south margin of the uinta basin respectively further south near the town of emery coals are present at the surface but most of the gas has been flushed out of the coals due to reduction of reservoir pressure and active water flow from the west therefore the entire ferron trend probably contained tremendous volumes of stratigraphically trapped coalbed methane before uplift and erosion exposed the southern coals to the atmosphere

the mechanisms of petrogenesis of the archaean continental crust comparison with modern processes the petrographic and chemical composition of magmatic rocks generated during the archaean appears to be different from that of post archaean rocks komatiites are widespread before 2 5 ga and rarely occur afterwards in addition the archaean continental crust is primarily ttg tonalitic trondhjemitic and granodioritic in composition exhibiting typical trondhjemitic differentiation trends whereas modern equivalents are granodioritic to granitic following classical calc alkaline differentiation trends this distinction becomes more prominent when rare earth elements ree are taken into account archaean ttg are yb poor ybn 8 5 and have high layb ratios 5 layb n 150 in comparison the post 2 5 ga granitoids emplaced in subduction zone geodynamic environments have high yb content 4 5 ybn 20 with very low layb n ratios 20 theoretical calculations and experimental petrology have shown that the ttg can be produced by partial melting of an archaean tholeiite transformed into garnet bearing amphibolite consequently the low heavy ree content of the ttg is explained by the influence of both residual garnet and hornblende in their source after 2 5 ga the role of these minerals in calc alkaline magma genesis becomes progressively less important which is interpreted in terms of a cooling earth model in modern subduction zone environments the subducted oceanic slab is relatively old and cold and the geothermal gradient along the benioff plane in low ca 10 c km consequently the down going lithosphere undergoes dehydration before partial melting is able to occur the liberated fluids are light ree and lile enriched and ascend into the overlying mantle wedge where they induced partial fusion the produced magmas separate from their mantle source region leaving a residue mainly composed of olivine and pyroxenes mantle derived magmas typically exhibit high yb contents due to low kdyb values for olivine and pyroxenes during the archaean the subducted lithosphere was relatively young and hot providing high geothermal gradients along the benioff zone thus partial melting of the subducted slab was possible at lower temperatures before dehydration would take place garnet and hornblende are the main residual phases accounting for the low yb contents of the archaean ttg this model can be tested using a modern analogue of archaean like subduction processes in south chile an oceanic ridge has subducted and all thermodynamic calculations indicate that this creates locally high geothermal gradients along the benioff zone thus in very small areas archaean like environments may be simulated in modern subduction zones the modern andesites produced in this environment show archaean geochemical characteristics with low ybn 5 whereas the majority of andesites along the andean arc have modern patterns with ybn ranging from 8 to more than 17 this conclusion was generalised to all young subducted lithospheres all over the world in conclusion it appears that since the archaean there has been a change in the site of continental crust genesis the location of calc alkaline magma source in subduction zone environments has migrated through time from the subducted slab to the mantle wedge this is a direct consequence of the progressive cooling of the earth

constraints on pb closure temperature in titanite based on rocks from the ungava orogen canada implications for u pb geochronology and p t t path determinations on the basis of multiequilibrium metamorphic pressure temperature p t estimates we have determined that 660 700 c is a reasonable minimum estimate of the closure t of pb diffusion in titanite a temperature significantly higher than previously suggested activity corrected reactions that produce titanite define narrow t stability fields 40 c that correspond closely to metamorphic p t determinations derived for coronitic garnet clinopyroxene hornblende samples growth of titanite occurring between 1789 and 1814 ma in the underthrust archean basement of the paleoproterozoic ungava orogen northern quebec is associated with retrograde metamorphism during underthrusting of the archean basement approx 1 b y after formation of the original granulitic assemblages

volcanology 2020 how will thermal remote sensing of volcanic surface activity evolve over the next decade abstract volcanological remote sensing spans numerous techniques wavelength regions data collection strategies targets and applications attempting to foresee and predict the growth vectors in this broad and rapidly developing field is therefore exceedingly difficult however we attempted to make such predictions at both the american geophysical union agu meeting session entitled volcanology 2010 how will the science and practice of volcanology change in the coming decade held in december 2000 and the follow up session 10 years later looking backward and forward volcanology in 2010 and 2020 in this summary paper we assess how well we did with our predictions for specific facets of volcano remote sensing in 2000 the advances made over the most recent decade and attempt a new look ahead to the next decade in completing this review we only consider the subset of the field focused on thermal infrared remote sensing of surface activity using ground based and space based technology and the subsequent research results this review keeps to the original scope of both agu presentations and therefore does not address the entire field of volcanological remote sensing which uses technologies in other wavelength regions e g ultraviolet radar etc or the study of volcanic processes other than the those associated with surface mostly effusive activity therefore we do not consider remote sensing of ash gas plumes for example in 2000 we had looked forward to a golden age in volcanological remote sensing with a variety of new orbital missions both planned and recently launched in addition exciting field based sensors such as hand held thermal cameras were also becoming available and being quickly adopted by volcanologists for both monitoring and research applications all of our predictions in 2000 came true but at a pace far quicker than we predicted relative to the 2000 2010 timeframe the coming decade will see far fewer new orbital instruments with direct applications to volcanology however ground based technologies and applications will continue to proliferate and unforeseen technology promises many exciting possibilities that will advance volcano thermal monitoring and science far beyond what we can currently envision

clues to the cause of the 2011 2013 campi flegrei caldera unrest italy from continuous gps data from 2006 to spring 2013 campi flegrei cf caldera italy was mostly uplifting at an increasing rate particularly high from 2011 we show that the 2011 2013 accelerated uplift and 1980 2010 inflation and deflation phases can be explained by a two source conceptual model similar to that proposed by amoruso et al 2014 reference model however pressurization of the sole thin quasi horizontal 4000 m deep source responsible for large scale 1980 2010 deformation can explain the whole 2011 2013 deformation while activity of the shallower solfatara hydrothermal source responsible for residual 1980 2010 deformation appears constant these results suggest a predominantly magmatic unrest in 2011 2013 near real time comparison of observations and reference model predictions can provide additional information for short term eruption forecasting at cf a similar approach could be followed also in other volcanic environments

textural geochronological and chemical constraints from polygenetic titanite and monogenetic apatite from a mid crustal shear zone an integrated epma sims and tims study abstract titanites extracted from a 520 9 ma syn orogenic syenite at otjimbingwe damara orogen namibia show shape colour and u pb systematics that vary with position in the syenite relative to a major shear zone most titanite fractions from syenite cropping out outside the shear zone are characterized by a medium brown anhedral core overgrown by a pale brown subhedral rim empa and sims analyses show that the cores are enriched in al fe and sometimes na mg and mn but also in ree nb and zr relative to the rim tims u pb ages from these titanites gave relatively imprecise 207pb 206pb ages between 680 21 ma and 695 20 ma as well as 570 8 ma to 604 9 ma mainly due to their low 206pb 204pb ratios combined th u pb relationships suggest that these titanites contain a component similar to ca 715 750 ma old titanite populations observed so far only in neoproterozoic syenites from the northern part of the orogen titanites from syenites within the shear zone are dark brown mostly euhedral to subhedral and display only occasionally a pale brown rim these titanites show decreasing concentrations of na mg al and fe and increasing concentrations of mn from core to rim interpreted to reflect growth zonation abundances of mree hree y nb and zr are higher in the rim than in the core 207pb 206pb ages obtained on these titanites range from 470 2 ma to 538 3 ma for most samples only the samples with the highest 206pb 204pb ratios between 350 and 230 have u pb ages similar to the previously published u pb zircon age of 520 9 ma from the same complex other titanite fractions with lower 206pb 204pb ratios have slightly older ages than ca 520 ma indicating some inheritance inherited titanite survived multiple metamorphic episodes in the damara orogen between ca 750 ma and 470 ma and the igneous event that lead to the intrusion of the otjimbingwe syenite at 520 ma these data imply a high closure temperature of u pb in titanite of 650 700 c consistent with previous studies coeval apatite has no apparent inheritance low 206pb 204pb ratios between 55 and 170 and u pb ages similar to or only slightly younger than the u pb zircon or titanite age obtained on the titanite fractions with the highest 206pb 204pb ratios assuming a closure temperature for u pb of 900 c for zircon 700 c for titanite and 450 c for apatite initial fast cooling of the complex can be inferred our data demonstrate that titanite can contain multiple age domains preserving a chronological and chemical record of previous igneous events

basement terrane correlations and crustal recycling in the western superior province nd isotopic character of granitoid and felsic volcanic rocks in the wabigoon subprovince n ontario canada abstract the western superior province represents a collage of mesoarchean continental 3 2 2 8 ga and neoarchean continental arc and oceanic 2 8 2 66 ga crustal fragments nd isotope data presented here for 89 felsic volcanic and plutonic rocks have been combined with compiled data to generate a data set of over 240 analyses from the wabigoon and winnipeg river subprovinces these samples from both oceanic and continental environments have been used as crustal probes their nd isotopic character used to investigate the extent of basement terranes the ancestry of crustal fragments their interaction with each other and the degree of sialic crustal reworking the wabigoon and winnipeg river subprovinces include three isotopically distinct terranes 1 the winnipeg river terrane comprises the winnipeg river subprovince the north central wabigoon and the north eastern wabigoon subprovince this region is dominated by neoarchean granitoid rocks with mesoarchean vestiges of previous workers have suggested that the boundary between the western wabigoon and winnipeg river terranes represents a cryptic suture resulting from a collision at circa 2 71 ga the boundary between the western wabigoon and marmion terranes although obscured by late intrusions may be a continuation of this suture zone the boundary between the winnipeg river and marmion terranes in the central wabigoon is also cryptic isotopic data suggest that the marmion terrane is allochthonous with respect to the winnipeg river terrane common magmatism in these two terranes at 2 93 2 87 ga suggests that they may have collided during this time in the eastern wabigoon subprovince this collision zone is speculated to occur at the humboldt bay high strain zone a complex history of crustal recycling throughout the mesoarchean and neoarchean is revealed which demonstrates the importance of autochthonous development of granite greenstone terranes in a continental environment the data also support models of tectonic accretion during the archean indicated by the presence of granite greenstone terranes of allochthonous origin

diffuse carbon dioxide emissions from hidden subsurface structures at asama volcano japan we measured diffuse carbon dioxide co2 flux and soil temperature around the summit of asama volcano japan to assess the diffuse degassing structure around the summit area soil co2 flux was measured using an accumulation chamber method and the spatial distributions of co2 flux and soil temperature were derived from the mean of 100 sequential gaussian simulations results show that soil co2 flux was high on the eastern flank of kamayama cone and the eastern rim of maekake crater the outer cone these areas mostly correspond to high temperature anomalies the average emission rate of diffuse co2 was calculated to be 12 6 t day 1 12 2 14 6 t day 1 such diffuse emissions account for 12 of the total diffuse and plume co2 emissions from the summit area the diffuse co2 anomalies probably reflect permeable zones controlled by local topography and hidden fractures bordering maekake crater the permeable zones are connected to the low electrical resistivity zone inferred to indicate both a hydrothermal fluid layer and an upper sealed layer made of clay minerals magmatic gas from the main conduit ascends to the volcano surface through this fluid layer and the permeable zones these insights emphasize that the pathways and the connection between the pathways and the source of diffuse co2 combine to create the pattern of heterogeneous diffuse co2 emission seen at the surface only by using a combination of gas measurements and geophysical tools can we begin to understand the dynamics of this system as a whole

origin and accumulation of petroleum in deep precambrian reservoir in baxian sag bohai bay basin china abstract the baxian sag is a mature exploration area the exploitation of deep sedimentary formation is becoming increasingly important as the further development potential of shallow plays faces growing challenges the discovery of the niudong gas condensate field from deep precambrian reservoirs indicates that potentially significant hydrocarbon resources remain to be discovered in deeper stratigraphic units this study was undertaken to better understand the generation and accumulation of hydrocarbons in deep reservoirs through integrated petroleum geochemistry fluid inclusion analysis and source rock analysis geochemical parameters of condensate and gas suggest that condensate and gas in precambrian reservoir have similar thermal maturity and are directly derived from gas prone source rock at high maturity levels the regional structure section and hydrocarbon distribution indicate that gas condensate in the nd1 well is more likely derived from lacustrine source rock in the paleogene shahejie formation refined source kitchen analysis indicates that lacustrine source rocks in the shahejie formation display a high degree of heterogeneity including organo facies c d e and f differences in the nature and composition of the expelled petroleum exist between organo facies due to variations in kerogen composition the orderly spatial distributions of gas oil ratio gor api gravity and gas carbon isotopes denote that the various fronts expelled hydrocarbons at different maturity levels from different organo facies this reflects the dynamic scenario of petroleum migration and accumulation from kitchen to shallow reservoirs the precambrian reservoir in nd1 well has experienced multiple charging with hydrocarbon expulsion at different maturity levels while hydrocarbons of lower maturity have arrived into the shallower reservoirs condensate and gas expelled at high maturation levels have efficiently accumulated in deeper prospects

polyphase tectono magmatic episodes as revealed by shrimp u pb geochronology and microanalysis of zircon and titanite from the central okcheon belt korea abstract the south central okcheon belt of the southern korean peninsula experienced polyphase granitic magmatism and deformation during the mesozoic this study presents integrated results of ion microprobe u pb geochronology and microtextural and microchemical analyses of zircon and titanite from pre tectonic baegnok and cheongsan and post tectonic boeun and sokrisan plutons with respect to the cheongsan shear zone the baegnok granodiorite sample yielded coherent zircon and titanite 206pb 238u ages of 225 6 1 8 and 223 9 4 4 ma indicating a rapid early cooling of the pluton the cheongsan k feldspar megacryst bearing biotite granite sample yielded a coeval zircon 206pb 238u age of 224 7 1 8 ma on the other hand the titanite grains from this rock are categorized into two age populations corresponding to the late triassic 214 3 7 9 ma and the late cretaceous 96 2 8 2 ma growth the older population is clearly of igneous origin considering partly preserved oscillatory zoning in back scattered electron images therefore the age indicates contrasting early cooling paths of the two pre tectonic plutons the younger population is interpreted to be the product of superimposed metasomatic reactions involving plagioclase ilmenite rutile epidote and calcite the two populations show different patterns in their atomic al fe ratios zircons from the boeun and sokrisan plutons yielded 206pb 238u ages of 172 2 2 1 and 94 2 2 1 ma respectively with the latter being indistinguishable from the younger titanite age of the cheongsan pluton the shrimp u pb age of syn deformational fine grained titanite grains lying on sigmoidal foliations in a mylonite from the cheongsan shear zone has a large error 165 47 ma due to their low u pb ratios possibly affected by post tectonic magmatic activities this study highlights the importance of detailed microanalysis prior to the isotopic dating of samples that have experienced complex tectono magmatic episodes

minto block superior province missing link in deciphering assembly of the craton at 2 7 ga plate tectonic models of the superior province are rooted in the granite greenstone and metasedimentary belts of the southern part of the craton north striking domains of the minto block in the northeastern part of the province evolved at similar times in 3 1 2 8 2 725 and 2 69 ga events requiring expansion of models of late archean assembly to accommodate minto geology western and eastern protocratons 3 1 2 8 ga rifted at 2 79 ga to produce an ocean basin that was mostly consumed by subduction at 2 725 ga the leaf river plutonic suite of cale alkalic hornblende biotite orthopyroxene clinopyroxene granodiorite represents magmatic arcs built on the protocratons whereas the intervening goudalie domain containing fault bounded fragments of rifted continental crust rift volcanics primitive oceanic crust 2724 ma island arc rocks and a 2718 ma back arc assemblage marks the suture terminal collision at 2 7 ga led to thickening and crustally derived granitoid magmatism the southern superior province also experienced vigorous activity between 2 725 and 2 69 ga as island arcs oceanic plateaus continental fragments and accretionary prisms were amalgamated progressively from north to south in a regime of dextral transpression then stitched by granites a northern proto superior craton had continental magmatic arcs built on its eastern and southern flanks in response to west northwest directed subduction orthogonal convergence in the east produced wide plutonic arcs in contrast to terrane accretion tectonics in the more oblique regime along the southern margin

fumarole monitoring with a handheld infrared camera volcan de colima mexico 2006 2007 abstract this paper describes a methodology for the monitoring of fumarole temperatures at medium ranges 6 km using a handheld infrared camera wavelength range 8 13 5 m as a relationship between fumarole temperatures gas flux and volcanic activity has been demonstrated by a number of studies fumarole temperature data has a potential use as a monitoring tool volcan de colima is an andesitic stratovolcano with a 300 m diameter summit crater formed by the destruction of the 2004 lava dome by a series of explosions in 2005 between january 2006 and august 2007 sequences of thermal images were recorded from a viewpoint 6 km to the north during regular 24 48 hour monitoring excursions the temperatures of fumaroles on the crater rim and the ground surface on the volcano s flanks were measured a methodology was developed to remove data affected by clouds or volcanic water vapour based on rates of temperature change and scatter within the data for the remaining data it is demonstrated mathematically that at this range typical variations in atmospheric transmissivity will affect the apparent temperatures by 2 c while a 25 change in fumarole heat flux would change it by 5 10 c the mean night time apparent temperature of the fumaroles was calculated for each excursion and showed an irregular decline over the 19 month period subtracting the radiant heat flux of flank rocks from those of the fumaroles removes seasonal variations and gives the clearest view of trends in the fumarole heat flux a sharp drop in fumarole temperature during february 2007 coincided with the emergence of a lava dome in the crater the declining fumarole temperature is interpreted to reflect decreasing gas flux from the crater in line with a change in eruptive regime from frequent small ash rich explosions to slow effusion of lava

integrated thermal infrared imaging and structure from motion photogrammetry to map apparent temperature and radiant hydrothermal heat flux at mammoth mountain ca usa abstract this work presents a method to create high resolution cm scale orthorectified and georeferenced maps of apparent surface temperature and radiant hydrothermal heat flux and estimate the radiant hydrothermal heat emission rate from a study area a ground based thermal infrared tir camera was used to collect 1 a set of overlapping and offset visible imagery around the study area during the daytime and 2 time series of co located visible and tir imagery at one or more sites within the study area from pre dawn to daytime daytime visible imagery was processed using the structure from motion photogrammetric method to create a digital elevation model onto which pre dawn tir imagery was orthorectified and georeferenced three dimensional maps of apparent surface temperature and radiant hydrothermal heat flux were then visualized and analyzed from various computer platforms e g google earth arcgis we demonstrate this method at the mammoth mountain fumarole area on mammoth mountain ca time averaged apparent surface temperatures and radiant hydrothermal heat fluxes were observed up to 73 7 c and 450 w m 2 respectively while the estimated radiant hydrothermal heat emission rate from the area was 1 54 kw results should provide a basis for monitoring potential volcanic unrest and mitigating hydrothermal heat related hazards on the volcano

time span of plutonism fabric development and cooling in a neoproterozoic magmatic arc segment u pb age constraints from syn tectonic plutons sark channel islands uk abstract new u pb zircon and titanite dates from syn tectonic plutons on the british channel island of sark constrain the time span of plutonism fabric development and cooling in this part of the neoproterozoic cadomian magmatic arc the tintageu leucogneiss is a mylonitic unit that was dated previously at 615 6 4 2 2 3 ma the port du moulin quartz diorite which intruded the tintageu unit contains a high strain solid state deformation fabric that is less intense than but parallel to fabrics in the leucogneiss and yields a u pb zircon date of 613 5 2 3 1 5 ma the little sark quartz diorite also displays solid state deformation fabrics in addition to relict magmatic textures and yields a u pb zircon date of 611 4 2 1 1 3 ma the north sark granodiorite is largely penetratively undeformed exhibits mainly magmatic fabrics and textures and has a u pb zircon date of 608 7 1 1 1 0 ma two fractions of titanite from each intrusion are essentially concordant and are identical within error with mean dates of 606 5 0 4 ma port du moulin quartz diorite 606 2 0 6 ma little sark quartz diorite 606 4 0 6 ma north sark granodiorite the new u pb data in combination with previous u pb and 40 ar 39 ar data and previous field studies confirm the syn tectonic nature of the sark plutons and quantify the time span ca 7 m y required for intrusion and sufficient crystallization of each body to record incremental strain during waning deformation titanite u pb and hornblende 40 ar 39 ar dates mark final cooling about 2 m y after intrusion of the last pluton

effects of igneous intrusions on coal petrology pore fracture and coalbed methane characteristics in hongyang handan and huaibei coalfields north china article i nfo the effects of igneous intrusions have proved to be important for the exploration and development of coalbed methane in many coal basins however the studies of the influences of localized intrusions on coalbed meth ane reservoirs are still insufficient in the context of five typical dike sill intrusion patterns i e dike cut through dike cut in floor intrusion by sill roof intrusion by sill and dual intrusions of roof and floor by sills this study investigates the changes of coal organic composition and pores fractures resulting from igneous intrusions the influences of igneous intrusions on coal composition mainly include the decrease of vitrinites especially telocollinite and the increase of inertinites contents as well as the formation of secondary devolatilization vacuoles and of exogenous desiccation microfractures the vacuoles have size of 0 1 10 m and the microfractures are commonly developed with a wide space and a significantly short length the microfractures typically have irregular dendritic filamentous and turtleback textures and densi ties of hundreds per 9 cm 2 the influences of igneous intrusions on coal pores and fractures vary significantly depending on the intrusion patterns the coal ranks after the intrusion and the nature of the adjacent forma tion surrounding the intrusion for the coals with a vrr 4 2 the intrusion significantly reduced the coal pore development for the coals with a vrr from 2 1 4 2 the development of the coal pores improved with decreasing distance to the contact for the coals with a vrr b2 1 the intrusion resulted in a slight improvement of the coal pore development a possible explanation for the increasing gas content near the intrusion is that the secondary vacuoles and microfractures induced an increase in the gas storage capacity and in the permeability of the coal reservoir the detailed intrusion patterns of sills and dikes contribute to the formations of the coalbed methane accumulation in coal seams and to the coal generated gas accumula tion in the reservoir of the highly permeable surrounding rocks

volcano surveillance using infrared cameras abstract volcanic eruptions are commonly preceded accompanied and followed by variations of a number of detectable geophysical and geochemical manifestations many remote sensing techniques have been applied to tracking anomalies and eruptive precursors and monitoring ongoing volcanic eruptions offering obvious advantages over in situ techniques especially during hazardous activity whilst spaceborne instruments provide a distinct advantage for collecting data remotely in this regard they still cannot match the spatial detail or time resolution achievable using portable imagers on the ground or aircraft hand held infrared camera technology has advanced significantly over the last decade resulting in a proliferation of commercially available instruments such that volcano observatories are increasingly implementing them in monitoring efforts improved thermal surveillance of active volcanoes has not only enhanced hazard assessment but it has contributed substantially to understanding a variety of volcanic processes drawing on over a decade of operational volcano surveillance in italy we provide here a critical review of the application of infrared thermal cameras to volcano monitoring following a summary of key physical principles instrument capabilities and the practicalities and methods of data collection we discuss the types of information that can be retrieved from thermal imagery and what they have contributed to hazard assessment and risk management and to physical volcanology with continued developments in thermal imager technology and lower instrument costs there will be increasing opportunity to gather valuable observations of volcanoes it is thus timely to review the state of the art and we hope thereby to stimulate further research and innovation in this area

heat flux based strategies for the thermal monitoring of sub fumarolic areas examples from vulcano and la soufriere de guadeloupe although it is relatively easy to set up the monitoring of soil temperature in sub fumarolic areas is quite rarely used to monitor the evolution of hydrothermal systems indeed measurements are highly sensitive to environmental conditions in particular daily and seasonal variations of atmospheric temperatures and rainfalls which can be only partially filtered by the established statistical analysis in this paper we develop two innovative processing methods both based on the computation of the heat flux in the soil the upward heat flux method uhf designed for dry environments consists in computing both the conductive and convective components of the heat flux between two thermocouples placed vertically in the cases of wet environments the excess of total heat method eth allows the integration of rain gauges data in order to correct the heat balance from the superficial cooling effect of the precipitations the performances of both processing techniques are faced to established methods temperature gradient and coefficient of determination on soil temperature time series from two test volcanoes at la fossa di vulcano italy the uhf method undoubtedly detects three thermal crises between 2009 and 2012 enabling to quantify not only the intensity but also the precise timing of the heat flux increase with respect to corresponding geochemical and seismic crises at la soufriere de guadeloupe french lesser antilles despite large rainfalls dramatically influencing the thermal behavior of the soil a constant geothermal heat flux is retrieved by the eth method confirming the absence of fumarolic crisis during the observation period february august 2010 being quantitative robust and usable in almost any context of sub fumarolic zones our two heat flux based methods increase the potential of soil temperature for the monitoring but also the general interpretation of fumarolic crises together with geochemical and seismological observations a spreadsheet allowing direct computation of uhf and eth is provided as supplemental material

geochronological constraints on the tectonic evolution of a late archaean greenstone belt wabigoon subprovince northwest ontario canada abstract u pb isotopic age analyses have been carried out on zircon and titanite from rocks near the contact between the kakagi lake savant lake volcanic belt ksvb within the wabigoon subprovince and the english river subprovince in northwest ontario canada two tonalite gneisses intruded by mafic dykes at tannis lake and caribou lake have minimum zircon ages of 3051 ma and 3075 ma respectively this contrasts with a 2775 1 ma age on zircon from a felsic tuff located within a lower predominantly mafic volcanic sequence in the interior of ksvb these data combined with previous studies indicate that ksvb is presently flanked by older sialic crust in the sioux lookout and kashaweogama lake areas lower mafic volcanic sequences are unconformably overlain by sedimentary units that are in sheared contact with overlying calc alkaline volcanic units titanite and zircon analyses from clasts within a basal conglomerate indicate a maximum age for deposition of 2698 4 ma this late age is confirmed by a 2703 2 ma zircon age for an unconformably underlying porphyry intrusion one clast gives a zircon age of 2903 16 ma suggesting that the sediments were at least partly derived from older material in the english river subprovince data from previous studies show that the structurally overlying calc alkaline volcanic sequences are at least 30 ma older than the sediments the absence of zircon inheritance in all but the youngest ksvb sequences as well as geological and geochemical arguments suggest that the greenstone belt evolved largely in an ensimatic environment in isolation from older sialic material the intervening oceanic crust must therefore have been consumed by subduction which led to arc magmatism and eventual collision between the arc ksvb and continental material english river subprovince the sediments unconformably overlying the lowermost mafic volcanic sequences were deposited in a partly subaerial continental environment since chemical and textural evidence suggests the lower mafic volcanic sequences were deposited in an oceanic environment they must have been obducted onto the edge of a continental block this was perhaps followed by nappe and thrust emplacement on top of the sediments of calc alkaline sequences derived from earlier arc magmatism continued compression resulted in isoclinal folding of the supracrustal sequences into their present vertical positions

polygenetic titanite records the composition of metamorphic fluids during the exhumation of ultrahigh pressure metagranite in the sulu orogen

controls on methane sorption capacity of indian coals details of methane sorption properties of some indian coals ranging in rank from high volatile bituminous c 0 62 ro max to medium volatile bituminous coal 1 46 ro max were investigated to determine the major factors influencing gas adsorption capacity and desorption rate variables studied included moisture content mineral matter content rank and coal type maceral composition adsorption isotherm analysis of dry coals showed that adsorption capacity followed a second order polynomial trend with rank equilibrium moist samples showed a linear increase in adsorption capacity with rank and had a significantly reduced adsorption capacity compared to the dry coals with the reduction being related to the moisture content mineral matter acted as a simple diluent to the gas adsorption capacity of the coals and was found to be nonadsorbent adsorption capacity moist was reduced by 0 32 cm3 g 10 ft3 gas t for every 1 increase in the ash yield bright and dull coal lithotypes showed strong separation in their adsorption capacities on an as analyzed basis with the bright coals adsorbing greater quantities of gas on a dmmf basis however no relationship was observed between coal type and gas storage capacity comparison of maceral composition with adsorption capacity dry confirmed this observation effective diffusivity de of methane through the coal was seen to be affected by coal type and rank effective diffusivity de decreased as rank increased which is related to the increasing microporous nature of the coal bulk coals tested had 2 3 times larger effective diffusivities than bright coals and dull coals had intermediate rates the larger de values for the bulk coals may be related to the presence of collodetrinite coupled with mineral matter which acts as higher permeability pathways for the gas compared with the high ash dull coals dominated by inertinite macerals differences were noted with similar age permian australian coals where methane adsorption capacities were larger and coal type had a stronger influence on adsorption capacity begin page 202

geochronology of the lumby lake greenstone belt a 3 ga complex within the wabigoon subprovince northwest ontario the lumby lake greenstone belt lies within the central predominantly metaplutonic terrane of the western wabigoon subprovince it is conformable with gneiss of the marmion lake tonalite batholith u pb analyses of zircons from two felsic tuffs and a quartz porphyry within the greenstone belt give a scattered lead loss pattern indicative of early disturbance the ages of the oldest concordant fractions agree however and define an age of 2999 1 m y for emplacement of these felsic units zircons from a tonalite gneiss within the marmion lake batholith are also somewhat disturbed the oldest abraded fraction is concordant and has an age of 3003 5 m y indicating that the gneiss is probably close in age to the supracrustal rocks u pb analyses of rutile from one of the felsic units give an age of 2690 5 m y and record the effect of late archean metamorphism three titanite fractions from the tonalite gneiss agree within error and have an age of 2809 1 m y the age and consistency of the titanite fractions indicate that titanite in this rock was formed as a result of a metamorphic event and was never subsequently disturbed this age is therefore a minimum estimate for high grade metamorphism of the gneiss the presence of a pre 2809 ma fabric in a gneiss of regional extent suggests that an early metamorphic deformational event affected this area these data constitute the first firm evidence for extensive 3 0 ga crust in the southern superior province and give the first evidence of a regional deformational event which predates cratonization of the superior province

coalbed methane characteristics of gates formation coals northeastern british columbia effect of maceral composition the majority of research reported on methane adsorption characteristics of coal seams has focused on vitrinite rich coals however western canadian coals are more inertinite rich than those of the western united states and are shown to differ in gas adsorption characteristics the influence of maceral composition upon gas adsorption characteristics of medium volatile coal samples from the middle cretaceous gates formation of northeastern british columbia was investigated lithotype coal facies samples were analyzed for surface area maceral and mineral composition and methane adsorption standard coal analyses were also performed proximate low temperature ash and equilibrium moisture the vitrinite content of the samples analyzed ranges from 18 to 95 vol min ral matter free the ash yield varies from 4 4 to 33 7 wt both maceral composition and mineral matter content have an important influence on adsorption characteristics as indicated by carbon dioxide surface areas and methane adsorption isotherms on a mineral matter free basis the amount of methane adsorbed generally increases with vitrinite enrichment the lowest methane adsorption occurs in the sample with the highest inertinite content carbon dioxide surface areas of the lithotypes range from 87 to 176 m2 g on a raw coal basis and from 99 to 184 m2 g on a mineral matter free basis surface area generally decreases with increased mineral matter content and increases with increased vitrinite content the increase in adsorption of both methane and carbon dioxide with increased vitrinite concentration is interpreted a resulting from differences in the pore size distribution of vitrinite and inertinite vitrinite is predominantly microporous whereas inertinite is meso to macroporous the monolayer volumes of carbon dioxide as calculated from the dubininradushkevich equation are higher than those of methane as determined from the langmuir equation but are correlated the methane adsorption isotherms and surface area data indicate that the maceral compositional variations in coal are at least as significant as coal rank in determining the potential volume of adsorbed methane and thus the coalbed methane potential of a deposit

the characteristics of coal reservoir pores and coal facies in liulin district hedong coal field of china the composition rank coal facies and coal pore structure characteristics of 15 coal samples were investigated systemically using methods of lithotype analysis maceral analysis proximate analysis mercury porosimetry analysis and nitrogen adsorption analysis these samples were directly collected from the working faces of no 4 8 9 seams in liulin district eastern margin ordos basin china four types of paleoenvironment including a wet forest swamp an intergradation forest swamp a drained forest swamp and a fresh water peat swamp were distinguished by lithotype and merceral analysis an r cluster analysis was performed to demonstrate the correlations between the coal facies and the pore structures the results showed that coal rank is the primary factor affecting the development of micropores and transition pores whereas coal facies control the development of seepage pores in similar coalification conditions especially in a local district and in a seam this work suggests that the vertical variations observed in coal properties macerals vitrinite reflectance mineral matters porosity bet specific area pore size distributions and pores connectivity were controlled by groundwater level fluctuations indicated by variations in the ground water index gwi in the ancient mires due to different accommodation and peat accumulation rates comparison of the porosity characteristics of various coal reservoirs developed in various coal facies indicates that wet forest swamp facies is favorable to the formation of a coalbed methane reservoir because of reasonable pore structure and good connectivity intergradation forest swamp facies rank the second and drained forest swamp facies are less advantageous

p t t paths and differential alleghanian loading and uplift of the bronson hill terrane south central new england late paleozoic u pb ages of sphene and 4 0 ar 3 9 ar cooling ages of amphibole and muscovite from rocks of the bronson hill terrane in connecticut and central massachusetts reflect a late paleozoic alleghanian overprinton acadian metamorphic rocks prograde alleghanian sphenes crystallized during the late pennsylvanian and eliminate the possibility that amphibole ages reflect delayed permian cooling from devonian acadian metamorphism fourteen new amphibole ages from connecticut form a north to south trend of decreasing age from 294 to 245 ma while in massachusetts four new amphibole ages together with three others from the literature produce a random carboniferous pattern seven new muscovite ages support existing data indicating uniform cooling throughout the bronson hill terrane through 350 c in the early triassic the rate of permian cooling defined by amphibole muscovite pairs increases from 4 c my in northern connecticut to 50 c my near long island sound hinged loading and hinged but delayed exhumation in the southern part of the bronson hill terrane with the hinge in central connecticut explain these ages and cooling rates as well as a southerly increasing metamorphic field gradient one dimensional thermal modeling indicates that loading of bronson hill rocks must have begun by the late mississippian the time of peak alleghanian metamorphic temperature decreases southward from early permian in northern connecticut to late permian to the south these results demonstrate that the metamorphic effects of the alleghanian orogeny are not restricted to the avalon terrane of southeastern new england on the contrary the alleghanian orogeny reset 4 0 ar 3 9 ar mineral ages recrystallized minerals partially melted felsic rocks and transposed fabrics at least as far west as the bronson hill terrane in south central new england

on the effects of petrographic composition on coalbed methane sorption abstract the effect of petrographic composition on the methane sorption capacity has been determined for a suite of coals and organic rich shales subbituminous and bituminous coals were separated into bright and dull lithotypes by hand picking the methane sorption capacities range between 0 5 and 23 9 cm 3 g at a pressure of 6 mpa the low volatile bituminous canmore coal and the anthracite sample have the highest capacities with the natural coke having the lowest for low rank coals there is no significant difference between bright and dull samples except for one coal with the dull sample having a greater sorption capacity than its bright equivalent for higher rank coals the bright samples have a greater methane capacity than the dull samples and the difference between sample pairs increases with rank the boghead coal samples have the highest sorption capacities in the liptinite rich coals suite and are higher than subbituminous to medium volatile bituminous samples pore size distribution indicates that methane is held as solution gas in liptinite rich coals and by physical sorption in micropores in liptinite poor coals these contrasting processes illustrate that liptinite rich samples need to be independently assessed the positive relationship between reactive inertinite content and methane sorption capacity occurs within the subbituminous to medium volatile bituminous coals because the reactive inertinite is structurally similar to vitrinite and have a higher microporosity than non reactive inertinite reactivity of inertinite should be assessed in cbm studies of dull coals to provide a better understanding of petrographic composition effects on methane capacity

monitoring active fumaroles through time lapse electrical resistivity tomograms an application to the pisciarelli fumarolic field campi flegrei italy abstract volcanoes are usually monitored through observations of many physical and chemical phenomena in the most dangerous cases as the one of the campi flegrei caldera italy great amount of data are collected both in discrete or continuously and regularly stored however how to transform such mass of data in a deeper understanding of the volcano dynamics is still an open question dissimilar information are in fact always hard to compare but just integrating all the available knowledge hazardous events could be prevented in a reliable way fluids as water and gasses mobilized in the subsoil by the heat induced by deep magmatic sources are widely recognized as the first engine of similar occurrences and the volcanic gas emissions represent together with the seismic activity one of the most considered precursors at the same time the electrical geophysical methods are the most applied in order to detect and characterize the fluid patterns in the subsoil so the integration of geoelectrical and geochemical observations should represent one of the most pursued approach in volcanoes monitoring on the contrary standard way to compare such data has been not yet codified the ert tomograms capability to individuate that parts of the subsoil where gasses cumulate is well understood in literature however we look for indications about its proficiency in associating the electrical resistivity changes relative to these zones once compared to the geochemical time series to deep related contributes distinguishing them from the seasonal ones the electrical signature of the fluid patterns reconstructed through a time lapse ert approach could be of relevance to better characterize the volcanic phenomena and their origins in this paper a first test of ert and geochemical time series integration was performed to enhance the understanding of the pisciarelli fumarolic field evolution now the most active area in the whole campi flegrei caldera

the difficulties of dating mafic dykes an antarctic example archaen gneisses of the vestfold hills of east antarctica are transected by several compositionally discrete suites of tholeiitic dykes a representative of one of those suites which has been dated in the present study shows that not only rb sr whole rock isochrons but also u pb zircon techniques if not properly applied can produce erroneous crystallisation ages two zircon populations were recovered from the mafic dyke itself one of which is 2 483 9 ma in age and clearly of xenocrystic origin the other yields an age of 1 025 56 ma which is not ascribed to the magmatic crystallisation of the dyke but rather to the time that it underwent metamorphic metasomatic alteration as a response to high grade tectonism in the adjacent mobile belt it is presumed that the zircon in question formed by the breakdown of another mineral or minerals possibly magmatic baddeleyite due either to ingress of a siliceous fluid or more probably by the release of silica from the breakdown of pyroxene to amphibole a cogenetic 1 2 cm wide felsic vein of late magmatic early hydrothermal origin also contains two zircon populations again most of the grains therein which are interpreted as of xenocrystic origin grew at 2 483 9 ma however a few euhedral zircons with very high u and th contents grew at 1 248 4 ma which is taken to be the formation age of both the felsic vein and the enclosing mafic dyke

u pb geoehronology and evolution of the english river subprovince an archean low p high t metasedimentary belt in the superior province u pb isotopic data for zircon monazite and titanite are used to assess the evolution of the late archean english river subprovince ers and adjacent domains of the winnipeg river subprovince in the northern superior province ontario the ers consists of turbiditic metasedimentary rocks deposited during the final stages of magmatic and tectonic accretion within the greenstone granite uchi subprovince to the north at around 2720 to 2710 ma the sedimentary rocks were intruded by a suite of calc alkalic plutons at 2698 ma major regional deformation amphibolite to granulite facies metamorphism anatexis and emplacement of an extensive peraluminous granitic suite culminated at 2691 ma late episodes of metamorphism metasomatism and emplacement of pegmatites occurred locally at circa 2680 and 2669 ma in contrast the winnipeg river subprovince to the south consists of widespread tonalitic suites formed mainly between 3200 and 2800 ma and granodioritic to granitic intrusions formed between 2710 and 2690 ma metamorphism occurred at around 2710 ma in southern domains and a distinct granulite facies event at around 2680 ma affected central and northern domains of the winnipeg river subprovince the rapid sequence of events recorded in the ers supports the notion that metamorphism was caused by thermal perturbations related to injection of granitic magmas these melts were generated through partial melting of the lower crust by a thermal anomaly presumably caused by mantle upwelling related to collapse of the inactivated subducting plate the short lived nature of the metamorphic events and their cyclicity follow the behaviour predicted by recent models linking the evolution of strain rates to episodes of segregation and upward magma transfer in the course of prolonged orogenic events

long term tir imagery processing for spatiotemporal monitoring of surface thermal features in volcanic environment a case study in the campi flegrei southern italy the tir monitoring system was partially funded by the 2000 2006 national operating programme and by the italian civil protection department in the framework of the 2004 2006 agreement with the istituto nazionale di geofisica e vulcanologia

contrasting types of late archean plutonic rocks in northwestern ontario implications for crustal evolution in the superior province abstract the late archean aulneau and lount lake batholiths have contrasting geochemical characteristics that are interpreted to be a consequence of derivation from different sources the aulneau batholith which was intruded into low grade metavolcanic rocks of the wabigoon subprovince is characterized by high na2o and low k2o rb and y together with enriched light rare earth elements lree near chondritic heavy rare earth elements hree negligible eu anomalies and mantle type initial sr and nd isotopic compositions these geochemical characteristics are consistent with derivation from the partial melting of metamorphosed tholeiitic basalt in contrast the lount lake batholith which was intruded into older 2 83 3 17 ga tonalitic plutonic rocks of the winnipeg river subprovince has relatively high k2o rb y and ree low na2o and prominent eu anomalies the initial sr and nd isotopic compositions of the lount lake batholith are consistent with a crustal source at least 200 400 ma older than the crystallization age of the batholith these geochemical characteristics indicate that the lount lake batholith originated from the partial melting of deeper level equivalents of the tonalitic metaplutonic rocks 2 83 3 17 ga which they intrude these results suggest that reworked 3 0 ga crust may be extensive in the winnipeg river subprovince and that the geochemical and isotopic signature of late archean plutonic rocks may be a useful reconnaissance tool in the identification of areas of extensive older crust the results can be interpreted within a uniformitarian model diachronous ensimatic magmatic arcs represented by the winnipeg river and western wabigoon subprovinces developed independently collision of these arcs at 2707 8 ma marks the cessation of subduction and related magmatic activity and the initiation of high grade metamorphism and melting in tectonically thickened portions of the crust

multistage zircon and titanite growth and inheritance in an archean gneiss complex winnipeg river subprovince ontario abstract the paper presents results from a u pb isotopic investigation of zircon and titanite from three phases of the archean sioux lookout gneiss complex at the margin of the gneissic plutonic winnipeg river subprovince wrs of the superior province the data reveal an intricate data pattern caused by inheritance and multistage crystallization and record the timing of two major orogenic events followed by a protracted post metamorphic evolution a zircon age of 2889 3 ma for a foliated pink granite correlates with that of similar units elsewhere in the superior province and reflects one of the first major episodes of crustal assembly in the pre kenoran evolution of the region tonalite and diorite from the same site yield zircon and titanite ages of 2704 2 and 2705 5 ma which correspond to the timing of major magmatism related to kenoran collision of the wrs with the adjacent wabigoon volcanic domains tonalite and diorite both contain abundant xenocrystic zircon moreover the late kinematic diorite also includes xenocrystic titanite which has a minimum age of 2730 ma and coexists with younger ca 2705 ma titanite and zircon two generations of titanite are also present in both the tonalite and the granite the earliest one reflects the 2704 ma plutonic metamorphic event whereas the second one indicates post metamorphic crystallization at 2650 and 2627 ma caused by superimposed hydrothermal activity and retrogression the data support the concept that the titanite can remain a closed system to pb diffusion at elevated temperatures as long as the crystals escape magmatic or metamorphic recrystallization conversely they also show that titanite can easily be produced by low temperature processes hence generalized interpretation of titanite ages in terms of regional cooling can be inappropriate

high precision u pb ages for granulite metamorphism and deformation in the archean kapuskasing structural zone ontario implications for structure and development of the lower crust abstract precise u pb isotopic ages for two subhorizontal granulite gneisses in the kapuskasing structural zone indicate that formation and emplacement occurred more than 50 m y after cessation of volcanism in the steeply folded nearby greenstone belts by successive stages of ductile underplating across a zone of crust mantle delamination volcanism and batholith formation had ceased by 2700 and 2680 ma respectively while granulite formation occurred between 2660 and 2640 ma and ductile deformation continued until 2585 ma emplacement of the oldest granulite caused the development of shear planes and melting in the older overlying tonalite while emplacement of the younger granulite caused rupturing and rehydration of the overlying older granulite widespread tectonic underplating is implied since all superior province granulites have similar young ages anomalous ar ages that post date accretion by about 150 m y and scrambled pb pb and rb sr whole rock systems also suggest that late low temperature alteration accompanied this event temporal relationships and the presence of post volcanic 2670 ma conglomerate cobbles at granulite grade support a model of ductile underplating of a post accretion thermally softened back arc fore arc complex with components welded onto an overlying volcanic plutonic complex at successively deeper levels multistage deformation in active fault zones and hydrothermal emplacement of major gold deposits in greenstone belts are coeval with ductile underplating with ages between 2670 and 2585 ma anomalously abundant gold production from archean rocks may indicate that shallow underplating granulitization and devolatization was a widespread phenomenon at this time post accretion ductile underplating must be considered as a primary cause of seismic reflectors in archean terrains

recent activity of nisyros volcano greece inferred from structural geochemical and seismological data this study summarizes the results of structural geochemical and seismological surveys carried out at nisyros volcano aegean sea greece during 1999 2001 field mapping and mesostructural measurements at the summit caldera lakki plain indicate that faults follow two main strikes ne sw and n s the n s striking fault depicts extensional features accommodating the left lateral component of motion of the ne sw striking main faults the ne sw preferred strike of the lakki faults and of the mineral filled veins as well as the distribution and ne sw elongation of the hydrothermal craters indicate that tectonics plays a major role in controlling the fluid pathway in the nisyros caldera the same ne sw trend is depicted by co2 anomalies revealed through detailed soil co2 flux surveys thus indicating a structural control on the pattern of the hydrothermal degassing degassing processes account for a thermal energy release of about 43 mw most of which occurs at lofos dome an area that was affected by hydrothermal eruptions in historical times the seismic study was conducted in june 2001 using a deployment specifically aimed at detecting signals of magmatic hydrothermal origin our instruments recorded local and regional earthquakes a few local long period events lp and bursts of monochromatic tremor local earthquake activity is concentrated beneath the caldera at depths generally shallower than 6 km plane wave decomposition of tremor signal indicates a shallow 200 m source located in the eastern part of the caldera conversely lp events depict a source located beneath the central part of the caldera in the area of lofos dome at depths in the 1 2 km range in agreement with geochemical and structural measurements these data suggest that both the deeper and shallower part of the hydrothermal system are subjected to instability in the fluid flow regimes probably consequent to transient pressurization of the reservoir these instabilities may be related to input of hot fluids from the deeper magmatic system as suggested by the variations in geochemical parameters observed after the 1997 1999 unrest episode the significance of seismological and geochemical indicators as precursors of hydrothermal explosive activity at nisyros is discussed

u pb geochronology of the mazinaw terrane an imbricate segment of the central metasedimentary belt grenville province ontario the mazinaw terrane in the central metasedimentary belt of the grenville province comprises volcanic sedimentary and plutonic rocks that were intensely folded and faulted and metamorphosed to as high as upper amphibolite facies u pb geochronology establishes an early period of magmatism and sedimentation at about 1280 1240 ma probably in a marginal basin setting and a multistage rhetamorphic evolution in the period between 1100 and 980 ma which was probably related to crustal thickening by imbrication during compression and wedging of the terrane some of the earliest magmatism formed calc alkalic volcanic rocks of kashwakamak formation at 1276 2 ma an associated sedimentary assemblage was intruded by the helena trondhjemite stock at 1267 5 ma a younger succession formed between 1250 and 1240 ma includes the bimodal volcanic mazinaw lake formation alaskitic granites of the norway lake and abinger plutons and a granodioritic gneiss phase of the cross lake pluton these units were covered

on the time scale of thermal cycles associated with open vent degassing thermal imagery obtained with portable infrared cameras is widely used to track and measure volcanic phenomena in the case of explosive eruptions both air and ground based thermal monitoring have enabled collection of data streams from relatively safe distances analysis of these data have enabled the characterisation of different explosive regimes parameterisation of eruptive plumes and assessment on the dynamics occurring in the shallow system here we explore the suitability of infrared imagers for investigating the short time scale eruptive behaviour of three basaltic volcanoes we present high time resolution thermal image data sets recorded at etna stromboli and k lauea volcano at the time of observations all three exhibited pulsed degassing signal processing of the mean apparent temperature time series highlights four broad classes of cyclic temperature changes at the three volcanoes based on characteristic time scales revealed in the periodograms 1 15 s 2 20 50 s 3 1 10 min and 4 12 90 min based on previous studies and integrating time series results with qualitative visible and thermal observations and in case of k lauea also with so2 column amounts in the plume we hypothesise that short cycles relate mainly to bursting of overpressured gas bubbles at the magma surface while long cycles might be associated with mechanisms of gas slug formation and ascent and to the emplacement and drainage of a lava lake at k lauea slow fluctuations may reflect periodic variations of the lava lake surface level the data from all three volcanoes reveal superimposition of degassing cycles of different frequencies suggesting link through common magmatic processes and physical properties

mineral matter in coals cleat minerals and their origin in some coals from the english midlands abstract in four coal seam profiles from the cannock coalfield west midlands the cleat joint frequency is a function of lithotype greatest in vitarin and is inversely related to bed thickness the cleat minerals were studied 1 under the microscope optical and electron 2 by x ray diffraction and 3 chemically the minerals present are pyrite marcasite sphalerite galena sulphides quartz kaolinite silicates ankerite calcite carbonates and apatite this sequence has features in common with diagenetic sequences recorded in other rock types and it is concluded that the cleat minerals in coal form in response to pore fluid evolution and movement during burial diagenesis the elements are thought to originate from both the coal and the associated sediments mainly mudrocks similarities in diagenetic sequences are in part a reflection of the importance of organic maturation reactions in all the rock types in the sequence whereas differences are attributed to the dominance of these reactions in the coal itself

time series analysis of high temperature fumaroles monitored on the island of vulcano aeolian archipelago italy abstract the exhalation activity at the la fossa cone vulcano island aeolian archipelago italy has been ongoing for more than 1 century many of the monitored geochemical and geophysical parameters have showed transient variations of energy release the time series analyses of fumarole temperatures presented in this paper enabled the sequence of observations to be defined and information from different monitoring stations to be integrated the motion of fluids feeding the fumaroles of the la fossa cone is driven by the thermal and kinetic energies that balance the seismic and volcanic forces active in the region and the temperatures of the fumaroles reflect the local response of the hydrothermal system to these forces during a 14 year period of observation from 1998 to 2012 fumarole temperatures showed various trends but also cyclic variations characterized by sharp increases the repetition of these variations during periods with different trends indicates that no physical variation occurred from the hydrothermal source to the surface during the analyzed period and after each periodic geochemical crisis the previous thermal conditions were restored although the continuous monitoring of high temperature fumaroles was limited to only a few sites the observed trends characterized the most important fumaroles in the area of vulcano island an evaluation of thermal energy release based on these spatially discrete measurements would be a speculative exercise in thermodynamics but the analyses of the recorded data represent a step forward in interpreting the signals from ongoing volcanic activity and in assessing the seismic risk

differential response of u pb systems in coexisting accessory minerals winnipeg river subprovince canadian shield implications for archean crustal growth and stabilization the u pb isotopic systems of zircon monazite titanite and some apatite and the pb isotopic composition of k feldspar have been investigated in three areas of the winnipeg river subprovince wrs of the superior province canada in order to define the timing of magmatic and metamorphic processes in this archean gneissic granitoid terrain

constraints on the geodynamic evolution of the southern superior province u pb la icp ms analysis of detrital zircon in successor basins of the archean abitibi and pontiac subprovinces of ontario and quebec canada abstract to investigate the tectonic development of the southern superior province new u pb laser ablation inductively coupled mass spectrometry analysis of detrital zircon was conducted on graywacke samples from successor basins of the abitibi and pontiac subprovinces the three successor basin successions investigated are the 2690 2685 ma porcupine assemblage and the 2679 2669 ma timiskaming assemblage of the abitibi subprovince and the 2682 ma sedimentary rocks of the pontiac subprovince predominately neoarchean zircon grains 80 95 of the total zircon population reflect local sources in the abitibi and pontiac subprovinces the successor basins were deposited within 100 ma of the majority of the detrital zircon grains primary crystallization ages which is consistent with patterns observed at modern convergent margin settings porcupine assemblage samples contain 5 mesoarchean zircon while pontiac subprovince and timiskaming assemblage samples contain 18 and 13 respectively no local mesoarchean sources exist in the abitibi or pontiac subprovinces suggesting input from an adjacent hinterland the higher proportion of mesoarchean zircon in the timiskaming assemblage relative to the porcupine assemblage suggests that detritus from the hinterland was more prevalent during the later stages of collision probably as a result of progressive uplift and denudation of the hinterland the high proportion of mesoarchean zircon in the pontiac subprovince sedimentary rocks may reflect an additional mesoarchean source comparison to previously published geochronology data for the superior province indicates that the hinterland was to the northwest and is in part composed of the winnipeg river marmion and opatica subprovinces patterns of contractional deformation successor basin formation and felsic plutonism progressively young to the south in the southern superior province and are interpreted in terms of accretionary processes detrital transport across subprovince or terrane boundaries progressive hinterland emergence and foreland directed propagation of the deformational front recorded by successor basins is similar to that observed in modern style collisional or accretionary orogens

monitoring super volcanoes geophysical and geochemical signals at yellowstone and other large caldera systems earth s largest calderas form as the ground collapses during immense volcanic eruptions when hundreds to thousands of cubic kilometres of magma are explosively withdrawn from the earth s crust over a period of days to weeks continuing long after such great eruptions the resulting calderas often exhibit pronounced unrest with frequent earthquakes alternating uplift and subsidence of the ground and considerable heat and mass flux because many active and extinct calderas show evidence for repetition of large eruptions such systems demand detailed scientific study and monitoring two calderas in north america yellowstone wyoming and long valley california are in areas of youthful tectonic complexity scientists strive to understand the signals generated when tectonic volcanic and hydrothermal hot ground water processes intersect one obstacle to accurate forecasting of large volcanic events is humanity s lack of familiarity with the signals leading up to the largest class of volcanic eruptions accordingly it may be difficult to recognize the difference between smaller and larger eruptions to prepare ourselves and society scientists must scrutinize a spectrum of volcanic signals and assess the many factors contributing to unrest and toward diverse modes of eruption

polymetamorphic evolution of the lewisian complex nw scotland as recorded by u pb isotopic compositions of zircon titanite and rutile u pb isotopic relations in zircon and titanite of granulite and amphibolite gneisses in the lewisian complex and bordering laxford front reveal complex discordance patterns indicating multiple late archean and early proterozoic crystallization overgrowth and pb loss events the earliest stages in the evolution of the complex remain poorly resolved zircon ages of 2710 ma date high grade metamorphism and magmatism probably related to tectonic and magmatic accretion in a continental arc setting a distinct event at 2490 2480 ma possibly initiated by metamorphism and deformation at high grade conditions caused amphibolitization of the granulites and emplacement of granitic pegmatites this event can be correlated with development of inverian shear zones and formation of granitoid layers along the laxford front the emplacement of a younger generation of granitoid sheets during the laxfordian event fromed hydrothermal titanite at 1754 ma in gneisses south of the laxford bridge and partially reset older titanite at scourie growth of secondary titanite and rutile also occurred during subsequent low grade metamorphism at 1690 1670 ma

secular variation in greenstone sequence development emphasizing superior province canada abstract evidence from the superior province of the canadian shield suggests the existence of several distinct lithostratigraphic associations in greenstone belts 1 quartz arenite and carbonate bearing sequences 2 mafic ultramafic volcanic sequences 3 mafic to felsic volcanic cycles and 4 timiskaming type sequences of fluviatile sediments and calc alkaline to alkaline volcanics recently recognized quartz arenite bearing sequences in the sachigo and wabigoon subprovinces are from base to top quartz arenite stromatolite bearing carbonate oxide facies iron formation and komatiite or tholeiite primary structures in the quartz arenites indicate shallow water deposition and represent mature sedimentation granitoid provenance of these sediments is postulated based upon petrography of coarse arenites and clasts of associated conglomerates the few dated superior province quartz arenite bearing sequences are 2 85 ga the shallow water origin of the primary structures and biota and the areal extent of the quartz arenite and carbonate sequences invite comparison with platform sediments at passive margins platform sequences unconformably overlie 3 ga granitoid rocks and older mafic volcanics where original lower contacts are preserved in two localities mafic volcanic sequences contain sheet flows iron formations and deep water argillites based on physical volcanology and sedimentology these sequences are compared to modern deep water mafic plain and hawaiian volcanism they generally underlie mafic to felsic volcanic cycles and overlie platform sequences mafic sequences are 2740 2700 ma in age mafic to felsic volcanic cycles consist of deep water tholeiitic flows overlain by shallow water to subaerial intermediate to felsic pyroclastics and flows the facies style of volcanism petrography and geochemistry of the mafic to felsic cycles most closely resemble the characteristics of crust in continental magmatic arc systems this type of lithostratigraphic association varies in age from 2775 to 2700 ma in the superior province with minor exceptions timiskaming type sequences consist of fluviatile conglomerate immature arenites and wackes with subaqueous to subaerial volcanics of variable chemistry longitudinal and lateral variation within fault bounded basins is extreme and the sequences have generally been affected by only late stages of deformation the combination of rock types facies distribution the fault bounded nature of the repositories and the locus of sedimentation along zones of transcurrent displacement suggest timiskaming sequences are best compared with modern pull apart basins superior province timiskaming sequences are within the superior province platform sequences are the earliest postorogenic lithostratigraphic unit in greenstone belts followed by mafic plain sequences arc volcanics and pull apart basins we suggest that platform sequences based upon limited evidence are preceded by an orogeny and that pull apart basins represent a subsequent orogeny the lithostratigraphic units above have distinct metallogenic associations 1 platform sequences based upon compilation of several shields may contain detrital au and u and oxide facies iron formations associated felsic volcanics contain no recognized volcanogenic cu zn deposits in the superior province the following metallogenic associations are noted 2 mafic plain sequences contain komatiite flow related ni deposits cu ni and platinum group deposits are associated with flows and coeval intrusions 3 arc volcanic sequences contain volcanogenic cu zn sulphide deposits and scarce deposits of porphyry type cu mo and 4 timiskaming sequences and related plutonism are related to lode au

new remote sensing techniques for the detection and quantification of earth surface co2 degassing abstract earth degassing specifically of carbon dioxide co 2 is of increasing interest with respect to the global carbon budget related climate effects earthquake and volcano eruption mechanisms as well as plant physiological reactions in gas rich environments investigations in all of these disciplines require the detection of surface co 2 degassing structures and quantification of their emissions we introduce minimal thermal change detection based on infrared imaging as a new remote sensing tool for the detection of earth surface thermal anomalies suiting among others to discover earth degassing locations of any origin the method allows for seamless areal search and monitoring of degassing structures in any terrain as proof of concept infrared imaging measurements were performed at the bossoleto vent on the eastern master fault of the siena graben tuscany italy it is known for the migration of a large amount of co 2 rich gas from deep geothermal reservoirs field data acquired confirmed the qualification of the method detection of co 2 degassing locations from infrared image time series worked reliably and optimal detection conditions were identified dry calm cloudless weather between dusk and dawn a simple model of heat exchange processes involved and observed was developed in a first attempt this model was applied to determine the gas exit temperature the area of gas thermal reach and the gas flux from recorded image series it is the first method that allows remote areal survey of mofette fields and the associated co 2 flux quantification sole from infrared image time series

u pb zircon ages and the evolution of the michipicoten plutonic volcanic terrane of the superior province ontario the archean michipicoten greenstone belt of the superior province in ontario is made up of supracrustal rocks divided into lower middle and upper metavolcanic rocks with associated metasedimentary rocks the belt has been intruded by granitic rocks and is also surrounded by granitic terranes based on u pb zircon geochronology it appears that volcanism in the area extended from at least 2749 to 2696 ma and plutonism and tectonic activity extended from at least 2888 to 2615 ma the various granitic and also one gabbroic plutons both internal and external to the greenstone belt were emplaced concomitantly with the three volcanic cycles as well as before and after the formation of the volcanic rocks zircon ages reported here together with previously published ages show that the area evolved in six major volcanic and plutonic events i 2888 ma plutonism ii 2743 ma volcanism and plutonism iii 2717 ma volcanism and plutonism iv 2696 ma volcanism and plutonism v 2668 ma plutonism and vi

drone with thermal infrared camera provides high resolution georeferenced imagery of the waikite geothermal area new zealand abstract drones are now routinely used for collecting aerial imagery and creating digital elevation models dem lightweight thermal sensors provide another payload option for generation of very high resolution aerial thermal orthophotos this technology allows for the rapid and safe survey of thermal areas often present in inaccessible or dangerous terrain here we present a 2 2 km 2 georeferenced temperature calibrated thermal orthophoto of the waikite geothermal area new zealand the image represents a mosaic of nearly 6000 thermal images captured by drone over a period of about 2 weeks this is thought by the authors to be the first such image published of a significant geothermal area produced by a drone equipped with a thermal camera temperature calibration of the image allowed calculation of heat loss 43 12 mw from thermal lakes and streams in the survey area loss from evaporation conduction and radiation an rgb visible spectrum orthomosaic photo and digital elevation model was also produced for this area with ground resolution and horizontal position error comparable to commercially produced lidar and aerial imagery obtained from crewed aircraft our results show that thermal imagery collected by drones has the potential to become a key tool in geothermal science including geological geochemical and geophysical surveys environmental baseline and monitoring studies geotechnical studies and civil works