volcano dome dynamics at mount st helens deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets the surface deformation field measured at volcanic domes provides insights into the effects of magmatic processes gravity and gas driven processes and the development and distribution of internal dome structures here we study short term dome deformation associated with earthquakes at mount st helens recorded by a permanent optical camera and seismic monitoring network we use digital image correlation dic to compute the displacement field between successive images and compare the results to the occurrence and characteristics of seismic events during a 6 week period of dome growth in 2006 the results reveal that dome growth at mount st helens was repeatedly interrupted by short term meter scale downward displacements at the dome surface which were associated in time with low frequency large magnitude seismic events followed by a tremor like signal the tremor was only recorded by the seismic stations closest to the dome we find a correlation between the magnitudes of the camera derived displacements and the spectral amplitudes of the associated tremor we use the dic results from two cameras and a high resolution topographic model to derive full 3 d displacement maps which reveals internal dome structures and the effect of the seismic activity on daily surface velocities we postulate that the tremor is recording the gravity driven response of the upper dome due to mechanical collapse or depressurization and fault controlled slumping our results highlight the different scales and structural expressions during growth and disintegration of lava domes and the relationships between seismic and deformation signals

more than ten years of lusi a review of facts coincidences and past and future studies abstract the lusi mud eruption in east java indonesia has continued unabated for more than ten years with no end in sight this review summarizes what has been learned about this intriguing system from its inception to the current 2017 well established metastable geysering system that continuously erupts mud breccia gas steam and water we discuss the initiation of lusi highlighting discrepancies and evidence through the published data to build a comprehensive database that emphasizes how the results converge towards a natural scenario of this system we argue that attempts to understand constrain or predict the behaviour of this system that rely on a drilling trigger can not explain subsequent observations on the other hand we show that a well constrained conceptual model recognizing lusi as a volcanically linked hydrothermal system has provided important insights for the documented observations over the last eleven years the response of lusi to the yogykarta earthquake falls directly within the range of earthquake triggering phenomena globally of similar hydrothermal geothermal systems suggesting a natural trigger as the more likely culprit for the lusi phenomenon we also offer some future directions of additional scrutiny for understanding this newborn tectonic scale volcanic hydrothermal complex

oldest known terrestrial anorthosite at mount narryer western australia abstract fragments of a deformed and metamorphosed layered anorthosite gabbro ultramafic intrusion called the manfred complex occur as inclusions in 3650 and 3400 ma old banded granite gneisses at mount narryer in the western gneiss terrain of the yilgarn block the complex is typical of a world wide group of archaean anorthosites characterized by very large primary grain sizes of equidimensional calcic plagioclase this is the first recorded occurrence of these anorthosites in australia pb pb and sm nd whole rock and u pb zircon geochronology given in the accompanying two papers fletcher i r rosman k j r and libby w g 1988 precambrian res 38 343 354 kinny p d williams i s froude d o ireland t r and compston w 1988 precambrian res 38 325 341 shows that the manfred complex is about 3730 ma old it is therefore the oldest known terrestrial anorthosite complex and one of the oldest known rock units on earth

triggering and dynamic evolution of the lusi mud volcano indonesia abstract mud volcanoes are geologically important manifestations of vertical fluid flow and mud eruption in sedimentary basins worldwide their formation is predominantly ascribed to release of overpressure from clay and organic rich sediments leading to impressive build up of mud mountains in submarine and subaerial settings here we report on a newly born mud volcano appearing close to an active magmatic complex in a backarc sedimentary basin in indonesia the location of the mud volcano close to magmatic volcanoes results in a high background temperature gradient that triggers mineralogical transformations and geochemical reactions at shallow depth the eruption of 100 c mud and gas that started the 29th of may 2006 flooded a large area within the sidoarjo village in northeast java thousands of people have so far been evacuated due to the mud flood hazards from the eruption since the initial eruption the flow rate escalated from 5000 to 120 000 m 3 d during the first eleven weeks then the erupted volume started to pulsate between almost zero and 120 000 m 3 d in the period august 14 to september 10 whereas it increased dramatically following swarms of earthquakes in september before reaching almost 180 000 m 3 d in december 2006 sampling and observations were completed during two fieldwork campaigns on the site the eruption of boiling water is accompanied by mud aqueous vapour co 2 and ch 4 based on geochemical and field results we propose a mechanism where the eruptions started following the 27th of may earthquake due to fracturing and accompanied depressurization of 100 c pore fluids from 1700 m depth this resulted in the formation of a quasi hydrothermal system with a geyser like surface expression and with an activity influenced by the regional seismicity

dynamics of outgassing and plume transport revealed by proximal unmanned aerial system uas measurements at volcan villarrica chile volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing and on geological timescales constitute an important source of volatiles to the earth s atmosphere measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles however significant gaps remain in our global inventories of volcanic emissions particularly for co2 which requires proximal sampling of a concentrated plume for those volcanoes where the near vent region is hazardous or inaccessible unmanned aerial systems uas provide a robust and effective solution to proximal sampling of dense volcanic plumes in extreme volcanic environments here we present gas compositional data acquired using a gas sensor payload aboard a uas flown at volcan villarrica chile we compare uas derived gas timeseries to simultaneous crater rim multi gas data and uv camera imagery to investigate early plume evolution so2 concentrations measured in the young proximal plume exhibit periodic variations that are well correlated with the concentrations of other species by combining molar gas ratios co2 so2 1 48 1 68 h2o so2 67 75 and h2o co2 45 51 with the so2 flux 142 17 t day from uv camera images we derive co2 and h2o fluxes of 150 t day and 2850 t day respectively we observe good agreement between time averaged molar gas ratios obtained from simultaneous uas and ground based multi gas acquisitions however the uas measurements made in the young less diluted plume reveal additional short term periodic structure that reflects active degassing through discrete audible gas exhalations

isotopic disequilibrium and lower crustal contamination in slowly ascending magmas insights from proterozoic anorthosites abstract many proterozoic anorthosite massifs show crustal isotopic signatures that have for decades fuelled debate regarding the source of these temporally restricted magmas are these signatures indicative of lower crustal melting or of significant assimilation of crustal material into mantle derived magmas traditional whole rock isotopic tracers sr nd pb and os like other geochemical petrological and experimental tools have failed to identify unambiguously the origins of the crust like signature and resolve the source controversies for these feldspathic cumulate intrusives we make use of high precision sr nd and pb isotopic compositions of mineral phases plag opx mag and comagmatic high pressure orthopyroxene megacrysts as well as whole rock anorthosites leuconorites from the mealy mountains intrusive suite mmis and the nain plutonic suite nps to probe the origin of the crustal isotopic signatures and assess the importance of differentiation at lower crustal depths this selection of samples represents fragments from various stages of the polybaric ascent of the magmas while the study of the mealy mountains intrusive suite and the nain plutonic suite is instructive as each is intruded into crust of significantly different age and isotopic composition we observe marked differences in the whole rock isotopic composition of proterozoic anorthosites and high pressure megacrysts e g e nd t 2 to 10 intruded into crustal terranes of different ages and isotopic compositions evidence for varying degrees of internal isotopic disequilibrium nd sr pb in anorthosites from these different terranes reinforces the notion that crustal contamination and more importantly the nature of the crustal assimilant has a profound influence on the chemical signature of proterozoic anorthosites while most samples from the mmis and nps show significant and measurable nd and pb disequilibrium sr compositions cluster around zero this decoupling in disequilibrium geometries cannot be explained by melting of the lower crust assimilation of crust with distinctive sr nd and pb isotopic compositions does however explain the origin of decoupling in internal mineral isotopic compositions we also find unexpected patterns of internal isotopic disequilibrium such as isotopically radiogenic orthopyroxene relative to plagioclase and differences in plagioclase isotopic disequilibrium between orthopyroxene and olivine bearing samples these various lines of evidence provide strong support for the generation of crustal isotopic signatures through assimilation and not anatexis of the lower crust these isotopic data show that anorthosite petrogenesis likely involves significant differentiation and solidification at lower crustal depths followed by ascent of high crystallinity bodies 50 crystallinity to mid or upper crustal levels we show that protracted lower crustal differentiation imparts a clear chemical and isotopic signature on mantle derived magmas of proterozoic anorthosites and that this process is central in the development of such slowly ascending plagioclase rich magmas

hydrothermal petroleum genesis migration and deposition in guaymas basin gulf of california hydrothermal activity and seabed mounds have been explored in guaymas basin by the deep sea drilling project dsdp piston coring dredging and diving with the deep submersible research vessel dsrv alvin sedimentary organic matter derived primarily from immature degraded microbial detritus is easily converted to petroleum under the hydrothermal regime these petroleums are mature and migrate in the fluids and by diffusion to the seabed the fluid migration is aided by near critical aqueous solution and supercritical carbon dioxide and hydrocarbons petroleum compositions vary from condensates to naphthenic to waxy all with significant amounts of asphaltenes and hydrothermal products such as olefins and toxic polynuclear aromatic hydrocarbons pah the heavy ends condense at the seabed depositing mainly as a cement with the sulfides and other minerals and to a lesser extent as entrapped oil and crystalline wax in vugs and conduits of the mounds the pah are high temperature resynthesis aromatiza

nature and extent of the deep biosphere in the last three decades we have learned a great deal about microbes in subsurface environments once these habitats were rarely examined perhaps because so much of the life that we are concerned with exists at the surface and seems to pace its metabolic and evolutionary rhythms with the overt planetary solar and lunar cycles that dictate our own lives and it certainly remains easier to identify with living beings that are in our midst most obviously struggling with us or against us for survival over time scales that are easiest to track using diurnal monthly or annual periods yet research efforts are drawn again and again to the subsurface to consider life there no doubt this has been due to our parochial interests in the resources that exist there the water minerals and energy that our society continues to require and that in some cases are created or modified by microbes however we also continue to be intrigued by the scientific curiosities that might only be solved by going underground and examining life where it does and does not exist but really is life underground just a peculiarity of most life on the planet and only a recently discovered figment of life or is it actually a more prominent and fundamental if unseen theme for life on our planet our primary purpose in this chapter is to provide an incremental assembly of knowledge of subsurface life with the aim of moving us towards a more complete conceptual model of deep life on the planet we aim to merge the consideration of the subsea floor and the continental subsurface because it is only through such a unified treatment that we can reach a comprehensive view of this underground life we also provide some thoughts on a way forward with what we

analytical model of surface uplift above axisymmetric flat lying magma intrusions implications for sill emplacement and geodesy abstract in this paper we develop a new axisymmetric analytic model of surface uplift upon sills and laccoliths based on the formulation of a thin bending plate lying on an elastic foundation in contrast to most former models also based on thin bending plate formulation our model accounts for i axi symmetrical uplift ii both upon and outside the intrusion the model accounts for shallow intrusions i e the ratio a h 5 where a and h are the radius and depth of the intrusion respectively the main parameter of the model is the elastic length l which is a function of the elastic properties of the bending plate and of the elastic foundation the model exhibits two regimes depending on the ratio a l when a l a l 5 the uplift is mostly restricted upon the intrusion when the elastic foundation is very stiff our model converges towards that of a clamped plate we provide as supplementary material a matlab function that calculates the surface uplift from the set of system and control parameters we discuss three possible applications of our model i the model can be used to describe sill propagation by introducing a propagation criterion for realistic values our model reproduces well the behavior of horizontal intrusions simulated in experiments ii the model can also be used to compute the critical size of saucer shaped sills it shows for instance that a soft elastic foundation favors the horizontal spreading of sills before they form inclined sheets iii we show that the classical mogi point source model cannot be used to constrain sill properties from the surface uplift we thus propose that our model can be used as a valuable alternative to both simple analytical models like mogi s and more complex numerical models used to analyze ground deformation resulting from sill intrusions in active volcanoes

genesis and evolution of the watukosek fault system in the lusi area east java abstract detailed analysis of two dimensional seismic lines acquired in the ne java basin has been performed to unravel the subsurface geology of the region around the lusi mud eruption this work revealed the existence of a system consisting of a complex set of faults here called the watukosek fault system forming triangular deformation zones converging at the top of the early miocene carbonates this system continues downwards with vertical individual fault segments often bordering the steep margins of the carbonate platforms the analysis of data includes the interpretation of seismic lines regional structural data inferred from basement gravity maps and present day main direction of stress results suggest that a possible rotation of stress direction from n40e s40w to n s occurred during the post miocene history of the java back arc tectonic evolution the watukosek fault system was first generated as a tensional lineament during the e w sinistral transpressive strain which involved the basement in this phase synthetic and antithetic riedel faults formed the former controlling the nw se orientation of the structural highs represented by oligo miocene carbonate platforms as a consequence of the rotation of the main principal stress direction to a n s direction the watukosek fault and similar parallel lineaments became sinistral riedel shears developing intense triangular deformation zones based on the stratigraphic position of gentle anticlinal deformations with axis corresponding to the n40e s40w oriented triangular deformation zones the transpressive strain linked to the n s main stress compression occurred likely in the late pliocene early pleistocene the detailed examination of a stratigraphy at the wells bjp 1 and porong 1 as well as b the seismo stratigraphic architecture of the entire succession in the study area allowed a new subsurface interpretation and revision of the stratigraphic units below lusi the thick early miocene tuban formation is found sandwiched between the coheval upper kalibeng formation and the early miocene carbonate of the kujung formation which in turn overlain the older ngimbang formation

sedimentary succession and evolution of the mediterranean ridge western sector as derived from lithology of mud breccia clasts abstract rock fragments from mud breccia extruded by mud volcanoes discovered during the ttr 4 cruise of the r v gelendzhik on the western mediterranean ridge are represented by a number of different lithologies they provide important information on the composition genesis and age of the deep seated sedimentary series of the basin lithological description and age determination of the main rock types obtained as clasts from mud breccia were made on the basis of a study of ninety seven samples depositional processes and environments of their accumulation were determined using sedimentological criteria the sedimentary section through which mud volcanoes erupted on the western mediterranean ridge includes aptian albian claystones late cretaceous limestones paleogene siliciclastic rocks and a variety of miocene limestones and mudstones the rock clasts studied throw insight into the evolution of the western sector of the eastern mediterranean basin from at least aptian time the aptian albian clayey series have been deposited in the marine conditions of a relatively narrow basin with a high input of terrigenous clayey material during the late cretaceous the basin enlarged terrigenous input into deep parts of the basin decreased and carbonate pelagic sedimentation became prevalent regression in paleogene time led to the deposition of thick terrigenous siliciclastic series of deltaic prodeltaic sediments extensive turbidite systems were emplaced in the western sector of the eastern mediterranean during the miocene along with predominantly carbonate pelagic sedimentation

fluid sediment interactions at eastern mediterranean mud volcanoes a stable isotope study from odp leg 160 abstract pore fluids from two odp sites at eastern mediterranean mud volcanoes have been analyzed for their cl concentration and their 18o and d isotopic composition the cl data span a wide range of concentrations from extremely depleted with respect to seawater as low as 60 mm at the crest of milano dome site 970 to strongly enriched up to 5 4 m at napoli dome site 971 chloride enrichment is known to be due to dissolving messinian evaporites whereas the source of the low cl fluid is deduced from stable isotope data presented here the isotopic composition of the endmember fluid is found to be 10 for 18o and 32 for d for low as well as for high cl waters from this signature it can be concluded that neither gas hydrates nor meteoric water play a significant role in the freshening of the pore water several other processes altering the 18o d composition of pore waters are discussed and considered to be of only negligible influence the process characterizing the isotopic composition of the fluid is found to be clay mineral dehydration mainly smectite illite transformation corresponding to a depth range of 3 5 7 km and an elevated temperature of about 120 165 c a quantitative estimate shows that this reaction is capable of producing the observed extreme cl depletion

drone high resolution infrared imaging of the lusi mud eruption abstract the use of low cost hand held infrared ir thermal cameras based on uncooled micro bolometer detector arrays became more widespread during the recent years thermal cameras have the ability to estimate temperature values without contact and therefore can be used in conditions where targets are difficult or dangerous to reach such as volcanic eruptions since may 2006 the indonesian lusi mud eruption continues to spew boiling mud water aqueous vapour co2 ch4 and covers a surface of nearly 7 km2 here we performed surveys above and around the erupting crater using a specifically equipped remote controlled aerial vehicle drone despite the harsh logistics and the continuously varying gas concentrations we managed to collect ir images composing mosaics to estimate the crater zone spatial and temporal thermal variations as well as that in the surrounding regions in this manuscript we provide a a description of the main processes that affect and control the acquisition of ir images b an overview of still non disclosed physical model used by the thermal camera employed during our survey i e flir i7 ir c a method for capturing high resolution infrared images over an erupting clastic system d analysis and interpretation of the acquired data and scientific results the results show that it is possible to obtain good quality mosaics also in inaccessible areas such as erupting craters where fixed reference points are not constant and where the presence of ir attenuation factors introduce errors in terms of temperature estimates however the ir camera radiative transfer model based on lowtran model allows the control of only some of the parameters that affect the attenuation of the ir spectrum this results in obtained crater temperature estimates up to 20 lower than those measured with hand held thermometers providing however very important information about the thermal gradient and the potential radioactive absorption factors the imaged lusi vent thermal pattern suggests the presence of shallow convective chambers inside the caldera zone these are activated by the rise of boiling mud breccia that suddenly cools and sinks the thermal survey conducted on the dry mud region to the ne of the crater reveals temperatures matching with those measured directly on the field with a hand held thermometer here the presence of hot spot anomalies and colder circular features is consistent with the migration of deeper warm fluids along a faulted and fractured area and with widespread pools distribution

the arjuno welirang volcanic complex and the connected lusi system geochemical evidences abstract for the first time we present the geochemical characterization of fluids emitted from the arjuno welirang volcanic complex and compare the results with those obtained sampling the neighboring spectacular lusi eruption site java island indonesia the isotopic composition of the hydrothermal and cold waters from the welirang volcanic complex indicate a meteoric origin for these springs with values ranging from 65 to 50 and 6 to 1 vs v smow respectively for d and 18 o the water erupted from the lusi site showed clustered higher d and 18 o isotopic values ranging around 6 and 10 vs v smow respectively we ascribe these results to mixing between hydrothermal fluids meteoric water saline formation fluids and water released during clay mineral illitization ultimately altered by additional evaporation processes the chemical and isotopic composition of fluids emitted from fumaroles and hydrothermal springs of the welirang volcano showed a clear magmatic signature where a co 2 dominated gas reveals 13 c co2 ranging between 5 9 and 2 4 and helium isotope with r ra 7 3 these values are very close to those measured at lusi site r ra 7 that also have high co 2 ch 4 ratio 1 7 2 2 supporting the high contribution of magmatic gases moreover a great contribution of andesitic water has been recognized in the water vapour emitted from the summit fumaroles converging geochemical data indicate that the plumbing system of the lusi eruption site is connected at depth with the arjuno welirang volcanic complex these data support a scenario where hydrothermal fluids from the volcanic system migrated in the sedimentary basin triggering metamorphic reactions in the organic rich sediments that ultimately resulted in a venting system at the surface after eleven years of incessant activity this venting system remains constantly fed by the fluids from the volcanic complex and became world known as lusi the largest ongoing clastic geysering system on earth

lunar magma ocean crystallization revisited bulk composition early cumulate mineralogy and the source regions of the highlands mg suite abstract crystallization of the lunar magma ocean lmo has been numerically modeled and its products inferred from sample observations but it has never been fully tested experimentally this study is a reexamination of the lmo hypothesis by means of the first experimental simulation of lunar differentiation two end member bulk moon compositions are considered one enriched in refractory lithophile elements relative to earth and one with no such enrichment a two stage model of magma ocean crystallization based on geophysical constraints is simulated and features early crystal suspension and equilibrium crystallization followed by fractional crystallization of the residual magma ocean an initially entirely molten moon is assumed part 1 of this study presented here focuses on stage 1 of this model and considers the early cumulates formed by equilibrium crystallization differences in mantle mineralogy resulting from different bulk moon compositions and implications for the source regions of the highlands mg suite refractory element enriched bulk moon compositions produce a deep mantle that contains garnet and trace cr spinel in addition to low ca pyroxene and olivine in contrast compositions without refractory element enrichment produce a deep dunitic mantle with low ca pyroxene but without an aluminous phase the differences in bulk composition are magnified in the residual melt the residual lmo from the refractory element enriched composition will likely produce plagioclase and ilmenite earlier and in greater quantities both compositions produce mg rich early cumulate piles that extend from the core mantle boundary to 355 km depth if 50 equilibrium crystallization and whole moon melting are assumed these early lmo cumulates provide good fits for the source regions for a component of the high mg ni and co poor parental magmas of the mg suite cumulates if certain conditions are called upon the olivine in early lmo cumulates produced by either bulk moon composition is far too rich in cr to be reasonable for the source regions of the mg suite meaning either core formation in the presence of s and or c must be invoked to deplete the lmo and the crystallizing olivine in cr or that current estimates of the bulk lunar cr content are too high we infer that melts meeting the criteria of the mg suite parents could be produced from early lmo cumulates by solid state kreep and plagioclase hybridization near the base of the crust and subsequent partial melting additionally we propose a revised model for mg suite petrogenesis

significance of mud volcanism 1 mud volcanism and diapirism have puzzled geoscientists for 2 centuries they have been described onshore and offshore in many places on earth and although they occur in various tectonic settings the majority of the features known to date are located in compressional tectonic scenarios this paper summarizes the main thrusts in mud volcano research as well as the various regions in which mud volcanism has been described mud volcanoes show variable geometry up to tens of kilometers in diameter and several hundred meters in height and a great diversity regarding the origin of the fluid and solid phases gas predominantly methane water and mud may be mobilized at subbottom depth of only a few meters but in places can originate from several kilometers depth with minor crustal or mantle input the possible contribution of mud extrusion to global budgets both from quiescent fluid emission and from the extrusive processes themselves is important in regions where mud volcanoes are abundant such as the collision zones between africa and eurasia fluid flux through mud extrusion exceeds the compaction driven pore fluid expulsion of the accretionary wedge also quiescent degassing of mud volcanoes may contribute significantly to volatile budgets and hence to greenhouse climate

trace element systematics of the neoarchean fiskenaesset anorthosite complex and associated meta volcanic rocks sw greenland evidence for a magmatic arc origin abstract new major and high precision icp ms trace element data on the neoarchean ca 2970 ma layered fiskenaesset complex and associated volcanic rocks southern west greenland provide new constraints on the petrogenesis and geodynamic setting of the complex the complex appears to have been emplaced as multiple sills of magma and crystal mush into oceanic crust tholeiitic basalts and gabbros forming an association of ca 550 m thick anorthosite leucogabbro gabbro and peridotite layers the fiskenaesset complex and the associated volcanic rocks were intruded by neoarchean tonalite trondhjemite and granodiorite ttg sheets during thrusting that was followed by several phases of isoclinal folding despite the intense deformation and amphibolite to granulite facies metamorphism primary cumulate textures and igneous layering are locally well preserved throughout the complex the presence of calcic plagioclase an75 95 and igneous amphibole in anorthosites gabbros and leucogabbros and hornblendite veins in peridotites suggests a hydrous magma source s the major and trace element compositions of tholeiitic basalts amphibolites suggest that they are petrogenetically related to the fiskenaesset complex by fractional crystallization the trace element systematics of the least altered anorthosites gabbros leucogabbros peridotites tholeiitic basalts and calc alkaline high magnesian andesites hma is collectively consistent with a supra subduction zone geodynamic setting on the log transformed tectonic discrimination diagram including la th sm th yb th and nb th ratios tholeiitic basalts display a trend projecting from mid ocean ridge basalt morb field to island arc basalt iab field this trend is interpreted as reflecting a transition from the neoarchean depleted upper mantle to a subarc mantle wedge following the initiation of intra oceanic subduction and arc migration collectively on the basis of field relationships petrographic features and geochemical characteristics the fiskenaesset complex is interpreted as a fragment of a neoarchean oceanic island arc on the basis of ree patterns anorthosites are divisible into four major groups 1 group 1 displays moderately depleted to slightly enriched lree and hree patterns 2 group 2 possesses strongly enriched lree and moderately depleted hree patterns 3 group 3 has strongly enriched lree and depleted hree patterns and 4 group 4 garnet anorthosite exhibits concave upward ree patterns that appear to have resulted from contamination of anorthositic magma by basaltic rocks or magma the different ree patterns in group 1 2 and 3 anorthosites are interpreted to reflect various depths of partial melting and variably enriched in incompatible elements source compositions the majority of anorthosites and leucogabbros were derived from depths above the garnet stability field

trinidad mud volcanoes where do the expelled fluids come from abstract in order to establish the origin of fluids expelled from mud volcanoes in trinidad we analyzed their major element trace element and isotopic h o sr compositions the mineralogical chemical and sr isotope compositions of associated expelled muds were also determined on the basis of their chemical and sr isotope compositions the fluids were divided into two groups those southwest and northeast of a major right lateral wrench fault the los bajos fault that both controls the chemical quality of the fluids and acts as a drain strontium isotopes were derived via mixing between a radiogenic source 0 71135 and a nonradiogenic source 0 70671 for both southwest and northeast groups however the nonradiogenic source possibly feeding the northeast group showed a lower sr concentration than that of the southwest group h and o isotope data show that the fluids became enriched in 18 o through interaction with wall rocks the fluids were originally oceanic but their properties were subsequently modified by diagenesis as evidenced by chemical data and mixing between fluids issued from two deep seated reservoirs and surface aquifer end members the gas phase expelled with the mud and the fluid through the mud volcanoes is composed mainly of methane with minor carbon dioxide the amount of expelled gas seems the same in samples from both sides of the los bajos fault the almost unique methane content of the gas phase and the large positive 18 o shifts of the reservoir end member as well as b li and ba contents reveal that the fluids from the deep seated reservoirs inherited their chemical compositions at high temperature fluid rock interactions estimates of equilibrium temperatures of the two deep seated reservoirs suggest that to acquire the estimated higher temperature 150 c the mud volcanoes must have been fed partly by a reservoir located at a depth of more than 3 km this depth corresponds to previous geologic information which located the deep seated reservoir in miocene sediments at such a comparable depth the mixing of the original fluids with a less deep seated reservoir and meteoric waters on the ascending path suggests the presence of a recharge mechanism and contributes to the dynamics of the expulsion itself

collecting field data in volcanic landscapes using small uas suas drones abstract the last several years have seen a very rapid increase in the development and availability of unmanned aerial vehicles systems uav or uas more commonly called drones uas are remotely operated aerial vehicles that can be fixed wing planes helicopters or aerial systems with multiple propellers small versions of uas here called suas in particular have become so prevalent that they can be easily purchased at general retail stores this paper seeks to review and summarize the use of suas in volcanic research given their size low cost and relative durability suas provide a light weight tool platform that is easy to transport to field locations quick to set up and easy to launch and control they require very little launch and recovery space because of these characteristics suas are useful in collecting immediate and real time aerial data especially in remote inaccessible dynamic and or hazardous volcanic environments in volcanic areas suas have been used for mapping sample collection thermal imaging magnetic surveys slope stability studies and as platforms for sensors to measure outgassing of co 2 and so 2 they are also becoming invaluable for real time hazard assessment during and after an eruption they are however limited by their flight time which is greatly affected by wind speeds since they are predominately made of plastic they are also impacted by the high thermal temperatures found in active volcanic areas which can degrade their structure and performance with continued technological improvement however suas have the potential to dramatically improve our ability to collect field data because of additional natural technological and legal challenges related to their use it is critical that users be aware of and adhere to all national and local laws associated with suas

generation of felsic crust in the archean a geodynamic modeling perspective abstract as a consequence of secular cooling of the earth there is generally no modern analog to assist in understanding the tectonic style that may have operated in the archean higher mantle temperatures and higher radiogenic heat production in the archean earth would have impacted the thickness and composition of the crust for this reason well constrained numerical modeling based on the fragmentary evidence preserved in the geological record is the most appropriate tool to evaluate hypotheses of archean crust formation the main lithology of archean gray gneiss complexes is the sodic tonalite trondhjemite granodiorite ttg suite melting of hydrated basalt at garnet amphibolite granulite or eclogite facies conditions is considered to be the dominant process that generated the archean ttgs taking into account geochemical signatures of possible mantle contributions to some ttgs models proposed for the formation of archean crust include subduction melting at the bottom of thickened continental crust and fractional crystallization of mantle derived melts under water saturated conditions we evaluated these hypotheses using a 2d coupled petrological thermomechanical tectono magmatic numerical model with initial conditions appropriate to the eoarchean mesoarchean based on the result of our experiments we identify three tectonic processes by which intermediate to felsic melts may be generated from hydrated primitive basaltic crust 1 delamination and dripping of the lower mafic crust into the mantle 2 local thickening of the crust and 3 small scale crustal overturns in the context of a stagnant deformable lid tectono magmatic geodynamic regime that is terminated by short lived subduction we identify two distinct types of continental crust the first type is a pristine granite greenstone like crust with dome and keel geometry formed over delaminating upwelling mantle which is mostly subjected to vertical tectonics processes by contrast the second type is a reworked accreted crust comprising strongly deformed granite greenstone and subduction related sequences and subjected to both strong horizontal shortening and vertical tectonics processes thus our study has identified a possible spatial and temporal transition from pristine granite greenstone like crust with dome and keel geometry to reworked accreted crust forming more felsic gneiss terranes in the archean we suggest that the contemporaneity of the proposed mechanisms can explain the variety and complexity of the archean geological record

abiotic methane on earth 1 over the last 30 years geochemical research has demonstrated that abiotic methane ch4 formed by chemical reactions which do not directly involve organic matter occurs on earth in several specific geologic environments it can be produced by either high temperature magmatic processes in volcanic and geothermal areas or via low temperature 100 c gas water rock reactions in continental settings even at shallow depths the isotopic composition of c and h is a first step in distinguishing abiotic from biotic including either microbial or thermogenic ch4 herein we demonstrate that integrated geochemical diagnostic techniques based on molecular composition of associated gases noble gas isotopes mixing models and a detailed knowledge of the geologic and hydrogeologic context are necessary to confirm the occurrence of abiotic ch4 in natural gases which are frequently mixtures of multiple sources although it has been traditionally assumed that abiotic ch4 is mainly related to mantle derived or magmatic processes a new generation of data is showing that low temperature synthesis related to gas water rock reactions is more common than previously thought this paper reviews the major sources of abiotic ch4 and the primary approaches for differentiating abiotic from biotic ch4 including novel potential tools such as clumped isotope geochemistry a diagnostic approach for differentiation is proposed

processes controlling water and hydrocarbon composition in seeps from the salton sea geothermal system california usa water mud gas and petroleum bearing seeps are part of the salton sea geothermal system ssgs in southern california seeps in the davis schrimpf seep fi eld 14 000 m 2 show considerable variations in water temperature ph density and solute content water rich springs have low densities 98 vol halogen geochemistry of the waters indicates that mixing of deep and shallow waters occurs and that near surface dissolution of halite may overprint the original fl uid compositions carbon isotopic analyses suggest that hydrocarbon seep gases have a thermogenic origin this hypothesis is supported by the presence of petroleum in a water dominated spring composed of 53 saturated compounds 35 aromatics and 12 polar compounds the abundance of polyaromatic hydrocarbons and immature biomarkers suggests a hydrothermal formation of the petroleum making the ssgs a relevant analogue to less accessible hydrothermal seep systems e g the guaymas basin in the gulf of california

deep and shallow sources for the lusi mud eruption revealed by surface deformation the lusi mud eruption in east java indonesia began in may 2006 and continues to the present previous analyses of surface deformation data suggested an exponential decay of the pressure in the mud source but did not constrain the location geometry and evolution of the possible source s of the erupting mud and fluids to map the surface deformation we employ multitemporal interferometric synthetic aperture radar and analyze a well populated l band data set acquired by the advanced land observing satellite alos between may 2006 and april 2011 we then apply a time dependent inverse modeling scheme volume changes occur in two regions beneath lusi at 0 3 2 0 km and 3 5 4 75 km depth the cumulative volume change within the shallow source is 2 3 times larger than that of the deep source the observation and model suggest that a shallow source plays a key role by supplying the erupting mud but that additional fluids do ascend from depths 4 km on eruptive timescales

prediction of coal face rockbursts and microseismicity in deep longwall coal mining a new method is proposed for predicting rockbursts as well as microseismicity in deep longwall coal mining the method is able to predict failure in the coal seam and in the rock mass by using 3 d elastic numerical stress analyses these locations were compared with the results of microseismic monitoring fracturing intensity and its variation with respect to face advance were represented by the maximum shear seismic moment release rate the seismic moment method was applied to three cases in the horonai coal mine and in the miike coal mine japan the first case considered panels w8 5u and ws 5 in the horonai coal mine at 1055 and 1125m deep even though no rockburst occurred areas where microseismic events were concentrated were predicted it was also clear by comparing calculated maximum shear seismic moment release rate to observed data that the magnitude of the seismicity and its variation with respect to the face advance were also successfully predicted the second case corresponded to panel w6 3 in the same mine from 915 to 985m deep microseismic monitoring had not yet been introduced however the rockburst in this panel was successfully predicted as fracturing of coal seam elements at the coal face the last case considered panels e3 e6 in the miike coal mine at 600 and 650 m deep respectively the location and intensity of microseismicity were again predicted in addition toppling as well as rockbursts were also predicted relations between the extent of the relief zone ahead of the coal face and the occurrence of rockbursts are discussed an effective method to prevent rockburst hazard is also proposed

mud volcanism an updated review abstract mud volcanism or sedimentary volcanism represents one of the most intriguing phenomena of the earth s crust with important implications in energy resource exploration seismicity geo hazard and atmospheric budget of greenhouse gases since the first review papers were issued at the beginning of 2000s a large amount of new geological geophysical and geochemical data has been acquired which clarified ambiguous concepts and significantly improved our knowledge of mud volcanism here we offer an updated review of the knowledge and implications of mud volcanoes with emphasis on the terminology used to describe different processes and structures the physical chemical and morphological characteristics of the several fluid emission structures the chemical properties of the released fluids in particular the molecular and isotopic composition of the gas the mud volcano formation dynamics and the several implications for petroleum exploration geo hazards and global atmospheric methane budget this review integrates new fluids data collected in azerbaijan and is complemented with field observations from various mud volcano provinces worldwide although the total number of mud volcanoes on earth is still uncertain 600 main onshore structures with a large variety in shapes and sizes are documented in recent global data sets and several thousand are assumed to exist in the oceans it is clear that a mud volcanoes are broadly distributed throughout the globe in active margins compressional zones of accretionary complexes thrust and overthrust belts passive margins deep sedimentary basins related to active plate boundaries as well as delta regions b they are specifically located in hydrocarbon bearing basins along anticline axes strike slips and normal faults and fault related folds in petroleum systems c they represent a specific category of natural gas oil seepage manifestation often related to deep and pressurised reservoirs d the main engine driving mud volcanism is given by a combination of gravitative instability of shales and fluid overpressure build up followed by hydrofracturing e hydrocarbons are generally of thermogenic origin while microbial gas is released in only a few cases mud volcanism on other planets e g mars and titan and microbial activity associated with gas seepage represent emerging issues and opportunities for future research

the lusi drone a multidisciplinary tool to access extreme environments abstract extreme and inaccessible environments are a new frontier that unmanned and remotely operated vehicles can today safely access and monitor the lusi mud eruption ne java island indonesia represents one of these harsh environments that are totally unreachable with traditional techniques here boiling mud is constantly spewed tens of meters in height and tall gas clouds surround the 100 m wide active crater the crater is surrounded by a 600 m diameter circular zone of hot mud that prevents any approach to investigate and sample the eruption site in order to access this active crater we designed and assembled a multipurpose drone the lusi drone is equipped with numerous airborne devices suitable for use on board of other multicopters during the missions three cameras can complete 1 video survey 2 high resolution photogrammetry of desired and preselected polygons and 3 thermal photogrammetry surveys with infra red camera to locate hot fluids seepage areas or faulted zones crater sampling and monitoring operations can be pre planned with a flight software and the pilot is required only for take off and landing a winch allows the deployment of gas mud and water samplers and contact thermometers to be operated with no risk for the aircraft during the winch operations that can be performed automatically the aircraft hovers at a safety height until the tasks controlled by the winch embedded processor are completed the drone is also equipped with gps connected co2 and ch4 sensors gridded surveys using these devices allowed obtaining 2d maps of the concentration and distribution of various gasses over the area covered by the flight path the device is solid stable even with significant wind affordable and easy to transport the lusi drone successfully operated during several expeditions at the ongoing active lusi eruption site and proved to be an excellent tool to study other harsh or unreachable sites where operations with more conventional methods are too expensive dangerous or simply impossible

a new hydrothermal scenario for the 2006 lusi eruption indonesia insights from gas geochemistry abstract the 29th of may 2006 gas and mud eruptions suddenly appeared along the watukosek fault in the north east of java indonesia within a few weeks several villages were submerged by boiling mud the most prominent eruption site was named lusi to date november 2011 lusi is still active and a 7 km2 area is covered by the burst mud breccia the mechanisms responsible for this devastating eruption remain elusive while there is consensus about the origin of the erupted mud the source of water is uncertain the origin of the gas is unknown and the trigger of the eruption is still debated in order to shed light on these unknowns we acquired a wide set of data of molecular and isotopic composition of gas sampled in several lusi vents in the surrounding mud volcanoes in the closest natural gas field wunut and in the hydrothermal vents at the neighbouring volcanic complex in the period 2006 2011 the boiling fluids erupted in the crater zone are apparently co2 dominated while colder ch4 dominated and c2 c3 bearing fluids are identified at several sites around the crater zone gas genetic diagrams maturity plots and gas generation modelling suggest that the hydrocarbons are thermogenic 13c1 up to 35 13c2 up to 20 deriving from marine kerogen with maturity of at least 1 5 ro for instance in the 4400 m deep ngimbang source rocks co2 released from the crater and surrounding seeps is also thermogenic 13c from 15 to 24 related to kerogen decarboxylation or thermal ch4 oxidation in deep rocks although three vents just outside the crater showed an apparent inorganic signature 7 5 4000 m magmatic intrusions and hydrothermal fluids responsible for the enhanced heat that altered source rocks and or gas reservoirs the neighbouring magmatic arjuno complex and its fluid pressure system combined with high seismic activity could have played a key role in the lusi genesis and evolution within this new model framework lusi is better understood as a sediment hosted hydrothermal system rather than a mud volcano

the geochemistry and origin of the hydrothermal water erupted at lusi indonesia abstract the spectacular lusi mud eruption started in northeast java the 29th of may 2006 despite extensive research the origin of the erupted water remains elusive and poorly constrained here we present a comprehensive study of the geochemistry of lusi waters compared with those collected from surrounding areas all collected between 2006 and 2013 including data from mud volcanoes and volcano hosted hydrothermal springs within this broad context the geochemical characteristics of the fluids expelled in the lusi region suggest that we can classify the waters in three groups 1 meteoric waters expelled in cold springs and artesian wells 2 hydrothermal waters typically mixed with meteoric waters and 3 formation water from marine sediments altered by diagenetic processes such as clay mineral dehydration samples collected from the lusi crater are cl and na dominated up to 527 mm and 471 7 mm respectively similar to seawater indicating that altered sedimentary formation waters are predominant in this system in addition they are enriched in sr up to 808 4 m and other elements commonly associated with hydrothermal systems such as li up to 877 6 m compared to 26 m in seawater some of these elements are up to ten times enriched compared to seawater values high temperature fluid mineral interactions in the subsurface appear to have facilitated the transfer of li and other mobile elements into the fluids high temperature fluid mineral interaction reactions are also supported by si concentrations significantly higher compared to other sampled mud volcanoes in the island crater samples also show the highest 18o values 5 after correction for evaporation compared to 1 at the mv localities 87sr 86sr ratios vary between of 0 7077 and 0 7083 and seem to reflect a general mixture of fluids from clay mineral dehydration carbonate recrystallization alteration of volcanic rocks and hydrothermal imprint eight years of geochemical monitoring indicate that the composition of the deep sourced lusi fluids remain fairly constant through time thus our findings show that the lusi crater waters represent a regional geochemical anomaly and we suggest that a combination of high temperatures in the source region and fluid rock interactions with silicates and possibly carbonate rich lithologies can explain the data this is consistent with a model where the emitted gases migrate from a deep seated 4 km source region likely associated with the presence of hot igneous intrusions and or high t reactions related to the presence of neighbouring active volcanoes

re os isotopic evidence for a lower crustal origin of massif type anorthosites massif type anorthosites are large igneous complexes of proterozoic age they are almost monomineralic representing vast accumulations of plagioclase with subordinate pyroxene or olivine and fe ti oxides the 930 myr old rogaland anorthosite province in southwest norway1 represents one of the youngest known expressions of such magmatism the source of the magma and geodynamic setting of massif type anorthosites remain long standing controversies in precambrian geology with no consensus existing as to the nature of the parental magmas or whether these magmas primarily originate in the earth s mantle or crust at present massif type anorthosites are believed to have crystallized from either crustally contaminated mantle derived melts that have fractionated olivine and pyroxenes at depth2 or primary aluminous gabbroic to jotunitic melts derived from the lower continental crust3 here we report rhenium and osmium isotopic data from the rogaland anorthosite province that strongly support a lower crustal source for the parental magmas there is no evidence of significantly older crust in southwest scandinavia and models invoking crustal contamination of mantle derived magmas fail to account for the isotopic data from the rogaland province initial osmium and neodymium isotopic values testify to the melting of mafic source rocks in the lower crust with an age of 1 400 1 550 myr

crustal evolution and the temporality of anorthosites abstract types of rock such as komatiite which formed entirely or dominantly during restricted time periods in solar system history are important indicators of how planetary bodies evolved in deep time in this paper we characterize three different types of temporally restricted anorthosites and discuss their significance to the broad scale evolution of planetary processes primordial anorthosites which constitute the bulk of the lunar crust were sampled during apollo and luna missions and have subsequently been identified in our meteorite collections they are characterized by very calcic plagioclase an93 98 and all have magmatic crystallization ages 4 3 ga suggesting that the earliest planetary crust forming processes on the moon and possibly elsewhere involved substantial if not total melting the magma ocean hypothesis which has endured for nearly 50 years argues that the lunar anorthositic rocks represent global flotation cumulates of plagioclase which crystallized after extensive precipitation and sinking of olivine and pyroxene another possibility revitalized by critical filtering of age data involves serial magmatism whereby the lunar crust was constructed by younger smaller episodic magmatic events on earth two distinct types of temporally restricted anorthosites offer opportunities to understand the evolution of terrestrial geodynamics tectonics and magmatic processes archean megacrystic anorthosites formed only between 3 73 and 2 49 ga as small bodies

isotopic evidence 87sr 86sr δ7li for alteration of the oceanic crust at deep rooted mud volcanoes in the gulf of cadiz ne atlantic ocean the chemical and isotopic composition of pore fluids is presented for five deep rooted mud volcanoes aligned on a transect across the gulf of cadiz continental margin at water depths between 350 and 3860 m generally decreasing interstitial li concentrations and sr 87 sr 86 ratios with increasing distance from shore are attributed to systematically changing fluid sources across the continental margin although highest li concentrations at the near shore mud volcanoes coincide with high salinities derived from dissolution of halite and late stage evaporites clayey terrigenous sediments are identified as the ultimate li source to all pore fluids investigated light delta li 7 values partly close to those of hydrothermal vent fluids delta li 7 11 9 parts per thousand indicate that li has been mobilized during high temperature fluid sediment or fluid rock interactions in the deep sub surface intense leaching of terrigenous clay has led to radiogenic sr 87 sr 86 ratios similar to 0 7106 in pore fluids of the near shore mud volcanoes in contrast non radiogenic sr 87 sr 86 ratios similar to 0 7075 at the distal locations are attributed to admixing of a basement derived fluid component carrying an isotopic signature from interaction with the basaltic crust this inference is substantiated by temperature constraints from li isotope equilibrium calculations suggesting exchange processes at particularly high temperatures 200 degrees c for the least radiogenic pore fluids of the most distal location advective pore fluids in the off shore reaches of the gulf of cadiz are influenced by successive exchange processes with both oceanic crust and terrigenous fine grained sediments resulting in a chemical and isotopic signature similar to that of fluids in near shore ridge flank hydrothermal systems this suggests that deep rooted mud volcanoes in the gulf of cadiz represent a fluid pathway intermediate between mid ocean ridge hydrothermal vent and shallow marginal cold seep due to the thicker sediment coverage and slower fluid advection rates the overall geochemical signature is shifted towards the sediment diagenetic signal compared to ridge flank hydrothermal environments c 2009 elsevier ltd all rights reserved

strike slip faults mediate the rise of crustal derived fluids and mud volcanism in the deep sea we report on newly discovered mud volcanoes located at 4500 m water depth 90 km west of the deformation front of the accretionary wedge of the gulf of cadiz and thus outside of their typical geotectonic environment seismic data suggest that fluid flow is mediated by a 400 km long strike slip fault marking the transcurrent plate boundary between africa and eurasia geochemical data cl b sr 87 sr 86 sr d 18 o dd reveal that fluids originate in oceanic crust older than 140 ma on their rise to the surface these fluids receive strong geochemical signals from recrystallization of upper jurassic carbonates and clay mineral dehydration in younger terrigeneous units at present reports of mud volcanoes in similar deep sea settings are rare but given that the large area of transform type plate boundaries has been barely investigated such pathways of fluid discharge may provide an important yet unappreciated link between the deeply buried oceanic crust and the deep ocean

10 years of lusi eruption lessons learned from multidisciplinary studies lusi lab abstract the spectacular lusi eruption started in northeast java indonesia on may 29th 2006 continuously erupting mud water gas oil and clasts ever since lusi provides an unprecedented opportunity to study the birth and the evolution of a large scale and hot mud eruption lusi is interpreted as a hybrid between a traditional hydrocarbon driven piercement structure mud volcano and a hydrothermal system fuelled by magmatic heat lusi is therefore an exciting natural laboratory for understanding analogue modern and palaeo piercement systems such as mud volcanoes sediment hosted hydrothermal systems and hydrothermal vent complexes this special issue collects recent multidisciplinary work completed in the framework of the erc funded lusi lab project these studies were conducted at and near lusi contributions span across disciplines such as engineering geochemistry geophysics geology and numerical modelling including fieldwork laboratory and theoretical approaches the acquired results contribute to characterise the dynamics of complex interactions between volcanism and an ongoing erupting clastic system lusi still saves many mysteries that will be unravelled by future scientific investigations

evidence for the submarine weathering of silicate minerals in black sea sediments possible implications for the marine li and b cycles 1 the role of sediment diagenesis in the marine cycles of li and b is poorly understood because li and b are easily mobilized during burial and are consumed in authigenic clay mineral formation their abundance in marine pore waters varies considerably exchange with the overlying ocean through diffusive fluxes should thus be common nevertheless only a minor li sink associated with the low temperature alteration of volcanic ash has been observed we describe a low temperature diagenetic environment in the black sea dominated by the alteration of detrital plagioclase feldspars fluids expelled from the odessa mud volcano in the sorokin trough originate from shallow 100 400 m deep sediments which are poor in volcanic materials but rich in anorthite these fluids are depleted in na k li b and 18o and enriched in ca2 and sr2 indicating that anorthite is dissolving and authigenic clays are forming using a simple chemical model we calculate the ph and the partial pressure of co2 pco2 in fluids associated with this alteration process our results show that the ph of these fluids is up to 1 5 ph units lower than in most deep marine sediments and that pco2 levels are up to several hundred times higher than in the atmosphere these conditions are similar to those which favor the weathering of silicate minerals in subaerial soil environments we propose that in black sea sediments enhanced organic matter preservation favors co2 production through methanogenesis and results in a low pore water ph compared to most deep sea sediments as a result silicate mineral weathering which is a sluggish process in most marine diagenetic environments proceeds rapidly in black sea sediments there is a potential for organic matter rich continental shelf environments to host this type of diagenesis should such environments be widespread this new li and b sink could help balance the marine li and li isotope budgets but would imply an apparent imbalance in the b cycle

transient deformation of karst aquifers due to seasonal and multiyear groundwater variations observed by gps in southern apennines italy we present gps hydrological and grace gravity recovery and climate experiment observations in southern apennines italy pointing to a previously unnoticed response of the solid earth to hydrological processes transient patterns in gps horizontal time series near to large karst aquifers are controlled by seasonal and interannual phases of groundwater recharge discharge of karst aquifers modulating the extensional 3 mm yr strain within the tectonically active apennines we suggest that transient signals are produced below the saturation level of the aquifers and above a poorly constrained depth in the shallow crust by time dependent opening of sub vertical fluid filled conductive fractures we ascribe this process to the immature karstification and intense tectonic fracturing favouring slow groundwater circulation and to multi year variations of the water table elevation influenced by variable seasonal recharge the vertical component displays seasonal and multi year signals more homogeneously distributed in space and closely correlated with estimates of total water storage from grace reflecting the elastic response of the lithosphere to variations of surface water loads the different sensitivities of vertical and horizontal components to the hydrologically induced deformation processes allow us to spatially and temporally resolve the different phases of the water cycle from maximum hydrological loading at the surface to maximum hydrostatic pressure beneath karst aquifers finally we suggest that transient deformation signals in the geodetic series of the apennines are correlated to large scale climatic patterns northern atlantic oscillation through their influence on precipitation variability and trends at the regional scale

thermal and chemical evolution of the terrestrial magma ocean abstract the earth is likely to have experienced a magma ocean stage during accretion thermal and chemical evolution of magma ocean is investigated based on a one dimensional two phase flow heat and mass transfer model differentiation at lower mantle pressure depends on the type of magma ocean and surrounding atmosphere if the magma ocean is formed by the blanketing effect of a solar type proto atmosphere extensive differentiation proceeds at lower mantle pressure if the magma ocean is formed by the blanketing effect of an impact induced steam atmosphere no differentiation at lower mantle pressure is likely if a very deep magma ocean is formed by a giant impact whether differentiation proceeds at lower mantle pressure or not depends on grain size viscosity of melt and or properties of a transient atmosphere on the contrary chemical differentiation likely proceeds at upper mantle pressure irrespective of magma ocean type a shallow magma ocean can remain for 100 200 my without any heating processes

uavs for volcano monitoring a new approach applied on an active lava flow on mt etna italy during the 27 february 02 march 2017 eruption abstract mt etna italy with 55 effusive events in the last six years is one of the most active volcanoes in the world with a million people living on its flank and thousands of tourists who visit it every summer for this reason the lava flow monitoring for risk mitigation and civil protection purposes is one of the fundamental tasks of the cartographic laboratory of the istituto nazionale di geofisica e vulcanologia osservatorio etneo this activity was traditionally performed using data collected from the field with terrestrial gps surveys and from helicopter taking visible and thermal images during the 27 february 02 march 2017 eruption the flyeye team applied unmanned aerial vehicles to monitor the active lava flow two high resolution uav surveys were performed on the lava flow field on the south flank of mt etna between 3050 and 2600 m a s l obtaining almost 1170 images structure from motion techniques were applied to create orthophotos and digital elevation models dem of the lava flow field and surroundings the obtained dem has a resolution of 14 2 and 20 7 cm px for the main lava flow and the west branch respectively on the wall the 96 of the lava flow field was mapped using aerial images by uav covering an area of 0 3 106 m2 lava flow volume was calculated with the topographic approach difference between post and pre eruption surface dem 2017 and dem 2014 respectively the impossibility of spreading the gcps homogenously distorted the resulting dem for this reason it was necessary to align the lava flow point clouds obtained from the photogrammetry software to the basal 2014 dem subtracting the two dems a lava flow thickness grid resulted leading to a total volume of 1 4 106 m3 and an error estimation of about 20 finally dividing the total volume for the effusion duration 63 h a mean output rate of 6 2 m3 s resulted the calculated volcanological parameters have the same order of magnitude of the previous activity of mt etna between 2011 and 2016 this research demonstrates that uav photogrammetry was successfully exploited during an eruptive crisis allowing a first fast processing to obtain an orthophoto of the lava flow field useful for decision makers and a further slower processing for the realization of a high resolution dem the latter makes it possible to update the topography another important argument for civil protection purpose this paper describes a methodology that could be applied during other natural events in extreme environmental conditions

formation of the neoarchean bad vermilion lake anorthosite complex and spatially associated granitic rocks at a convergent plate margin superior province western ontario canada abstract the bad vermilion lake anorthosite complex henceforth the bvla complex in western ontario is one of the well exposed anorthosite bearing archean layered intrusions in the superior province canada this study presents new whole rock major and trace element data for the various units of the complex oxygen isotope data for the anorthosite and major and trace element data for the spatially associated granitic rocks intruding the bvla complex to constrain their petrogenetic and geodynamic origin zircons from granitic rocks have yielded a 207pb 206pb age of 2716 18 ma constraining the minimum intrusion age of the complex despite deformation and greenschist facies metamorphism primary igneous textures are locally well preserved in the bvla complex its whole rock major and trace elemental compositions and the oxygen isotopic systematics appear not to have been substantially modified by deformation and metamorphism mantle like oxygen isotope signatures and major and trace element compositions are inconsistent with significant crustal contamination of the bvla complex during its emplacement the existence of primary calcic igneous plagioclase coherent negative nb anomalies nb nb 0 08 0 88 and geochemical similarities between gabbros from the bvla complex and gabbros from cenozoic arcs collectively suggest an intra oceanic subduction zone geodynamic setting for the complex near flat ree patterns in the various units of the bvla complex suggest that they were derived from melting of a shallow source beneath a subarc mantle wedge trends in immobile major e g mgo and trace e g zr element data indicate that the mineralogical composition of the complex can be explained by fractional crystallization and accumulation of olivine orthopyroxene clinopyroxene plagioclase and possibly amphibole compositionally the bordering granitic rocks are a2 type and strongly enriched in th and ree 100 times chondrite and depleted of ba sr eu and ti we suggest that they formed in a post collisional extensional tectonic regime following emplacement of the bvla complex in an oceanic arc

strike slip faulting as a trigger mechanism for overpressure release through piercement structures implications for the lusi mud volcano indonesia piercement structures such as hydrothermal vent complexes pockmarks and mud volcanoes are found in various geological settings but are often associated with faults or other fluid focussing features this article aims to investigate and understand the mechanisms responsible for the formation of piercement structures in sedimentary basins and the role of strike slip faulting as a triggering mechanism for fluidization for this purpose four different approaches were combined fieldwork analogue experiments and math

massive layer of pure anorthosite on the moon 1 we present a new global survey of the purest anorthosite pan rock using the spectral profiler onboard kaguya we found that pan rocks are widely distributed over the moon including the feldspathic highland terrain and the south and north polar regions all pan sites are associated with huge impact structures with diameters larger than 100 km based on the global distributions of pan and olivine rich sites we propose the existence of a massive pan layer with a thickness of 50 km below an uppermost mafic rich mixed layer with a thickness of 10 km below the pan layer a lower crustal layer with olivine rich materials may be present on the nearside but not on the far side of the moon the existence of a pan layer with a thickness of 50 km suggests an al2o3 abundance of 33 to 34 wt in the lunar crust which is higher than previous estimates of 32 wt our data indicate the massive production event of pan during the early stage of the formation of the moon supporting the lunar magma ocean scenario

disturbance of isotope systematics during experimental shock and thermal metamorphism of a lunar basalt with implications for martian meteorite chronology to better determine the effects of impact related processes on radiometric chronometers in meteorites we undertook an isotopic study of experimentally shocked and heated samples of lunar basalt 10017 shock experiments at 55 gpa were completed on one subsample and a second subsample was heated in an evacuated quartz tube at 1000 c for 170 h a third subsample was maintained as a control samarium neodymium rb sr 238 u 206 pb and 206 pb 207 pb isotopic analyses were completed on mineral fractions leached and unleached leached whole rocks and complementary acid leachates disturbance in the shocked and heated samples was evaluated through comparison of their isochron diagrams with those of the control sample the sm nd isotope system was the least disturbed the rb sr isotope system was more disturbed and the 238 u 206 pb and 206 pb 207 pb isotope systems were the most disturbed by shock and annealing samples that experienced extended heating demonstrated greater isotopic disturbances than shocked samples in some cases the true crystallization age was preserved and in others age information was degraded or destroyed in no case did the experiments generate isochrons that maintained linearity while being rotated or completely reset although our results show that neither experimental shock nor thermal metamorphism alone can account for the discordant ages represented by different isotope systems in some martian meteorites we postulate that shock metamorphism may render a meteorite more susceptible than its unshocked counterpart to subsequent disturbance during extended impact related heating or aqueous alteration the combination of these processes may result in the disparate chronometric information preserved in some meteorites

implications of melting for stabilisation of the lithosphere and heat loss in the archaean abstract the increased depth and volume of melting induced in a higher temperature archaean mantle controls the stability of the lithosphere heat loss rates and the thickness of the oceanic crust the relationship between density distributions in oceanic lithosphere and the depth of melting at spreading centres is investigated by calculating the mineral proportions and densities of residual mantle depleted by extraction of melt fractions the density changes related to compositional gradients are comparable to those produced by thermal effects for lithosphere formed from a mantle which is 200 c or more hotter than modern upper mantle if archaean continental crust formed initially above oceanic lithosphere the compositional density gradients may be sufficient to preserve a thick archaean continental lithosphere within which the archaean age diamonds are preserved the amount of heat advected by melts at mid ocean ridges today is small but heat advected by melting becomes proportionally more important as higher mantle temperatures lead to a greater volume of melt and as the rate of production of oceanic plates increases archaean tectonics could have been dominated by spreading rates 2 3 times greater than now and with mantle temperatures between ca 1600 c and 1800 c at the depth of the solidus mid ocean ridge melting would produce a relatively thick but light refractory lithosphere on which continents could form protected from copious volcanism and high mantle temperatures

significance of hydrocarbon seepage relative to petroleum generation and entrapment near surface indications of migrating hydrocarbons provide the petroleum systems analyst critical information about source organic matter type maturation organic maturity migration migration pathway delineation and in selected geologic settings specific prospect hydrocarbon charge all petroliferous basins exhibit some type of near surface signal but the hydrocarbon leakage to surface is not always detectable with conventional seep detection methods understanding the petroleum seepage system hence petroleum dynamics of a basin is key to understanding and using near surface geochemical methods for basin assessment and prospect evaluation the relationships between near surface hydrocarbon seepage and subsurface petroleum generation and entrapment are often complex the petroleum seepage system contain four key elements seepage activity qualitative expressions of relative leakage rates active vs passive and episodic vs continuous seepage type concentration of migrated thermogenic hydrocarbon relative to in situ material macro vs micro migration focus major direction of bulk flow leakage relative to the subsurface hydrocarbon generation and or entrapment and near surface seep disturbances near surface processes which can greatly alter or block seepage signals the rate and volume of hydrocarbon seepage to the surface greatly control near surface geological and biological responses and thus are the best method of sampling and analysis to detect hydrocarbon leakage effectively to properly predict subsurface petroleum properties interpretation of near surface geochemical data must recognize many potential problems including recent organic matter input transported hydrocarbons bacterial alteration mixing contamination and fractionation effects surface geochemical data should always be integrated with other geological data calibration datasets to determine the utility of near surface geochemical techniques within particular basinal settings are essential when evaluating prospects for hydrocarbon charge