new evidence for the origin of hypersaline pore fluids in the mediterranean basin abstract the br cl li cl and b cl ratios and boron isotope compositions of hypersaline pore fluids from dsdp sites 372 and 374 were measured in an attempt to evaluate the origin of the brines in site 374 the relationships between the cl concentrations up to 5000 mm and br cl 12 10 3 na cl as low as 0 1 b cl 2 5 10 3 and 11b values 43 55 o ofthedeepporewererbetween 300 and 055 mfsf loceted withinthe mesniniansediments feflecrremnantoof 65 fold evaporated sea water the original evaporated sea water was modified by 1 dilution with overlying or less saline water by about 30 and 2 slight dissolution of nacl evaporites the variations in 11b show a continuous increase in 11b values with depth in site 374 up to 66 7 oat adepthof 000 mfsf upperpliocene marlsecliments hhe conspicuous 11b enrichment trend is consistent with elemental boron depletion which was calculated from the expected boron concentrations of evaporated sea water with corresponding br cl and na cl ratios li cl variations also show a depletion of li relative to evaporated sea water the apparent depletions of b and li as well as the 11b enrichment reflect uptake of these elements by clay minerals at low water sediment ratios

a new method to assess long term sea bottom vertical displacement in shallow water using a bottom pressure sensor application to campi flegrei southern italy we present a new methodology using bottom pressure recorder bpr measurements in conjunction with sea level water column and barometric data to assess the long term vertical seafloor deformation to a few centimeters accuracy in shallow water environments the method helps to remove the apparent vertical displacement on the order of tens of centimeters caused by the bpr instrumental drift and by seawater density variations we have applied the method to the data acquired in 2011 by a bpr deployed at 96 m depth in the marine sector of the campi flegrei caldera during a seafloor uplift episode of a few centimeters amplitude lasted for several months the method detected a vertical uplift of the caldera of 2 5 1 3 cm achieving an unprecedented level of precision in the measurement of the submarine vertical deformation in shallow water the estimated vertical deformation at the bpr also compares favorably with data acquired by a land based gps station located at the same distance from the maximum of the modeled deformation field while bpr measurements are commonly performed in deep waters where the oceanic noise is relatively low and in areas with rapid large amplitude vertical ground displacement the proposed method extends the capability of estimating vertical uplifts from bpr time series to shallow waters and to slow deformation processes

boron isotope geochemistry as a tracer for the evolution of brines and associated hot springs from the dead sea israel abstract a boron isotope study combined with analyses of elemental boron lithium and chlorine is used to suggest that brines from the dead sea and on shore hypersaline thermal springs hamme yesha hamme zohar and hamme mazor are the products of interaction of evaporated seawater with detrital sediments the high 11b values of the dead sea brines 55 7 to 57 4 versus nbs 951 and the hot springs 52 2 to 55 7 and low b li ratios 2 0 to 2 3 and 2 5 to 2 7 respectively relative to seawater indicate preferential removal of 10b from the brines and hence boron adsorption onto clay minerals the brackish en feshcha springs and the freshwater en dawid and nahal arugot springs yield lower b contents and 11b values 37 7 to 40 6 and 33 8 to 36 9 respectively the 11b values and b contents of diluted dead sea brines lie on calculated mixing lines between the composition of the brackish and freshwater springs with the composition of the dead sea the 11 b values of the hot springs however given their boron content are significantly lower than those of the mixing lines thus waters from the hot springs cannot be a mixing product of the dead sea brine with freshwater instead the dead sea brine has evolved from the brines of the hot springs through further isotopic fractionation and boron adsorption onto detrital sediments

halide systematics in interstitial waters of ocean drilling sediment cores abstract the distribution of dissolved halides cl br i in interstitial waters of deep drill holes in the ocean is discussed for a number of environments hemi pelagic sediments hydrate containing sediments sediments affected by halide brines and also in hydrothermal environments the importance of the diagenesis of organic c in the production of i and br is discussed with reference to the observations of dissolved so 4 2 and nh 4 in the pore fluids more importantly in the zone of methano genesis below the so 4 2 reduction zone and usually associated with high organic c accumulation rates increases in i and br are of importance and usually are much higher than the increases observed in the so 4 2 reduction zone in pore fluids affected by dissolution of evaporites the br cl is often a strong indicator of the degree of evaporation of seawater demonstrated from results obtained in the mediterranean sea dissolution of halites on the other hand leads to br cl much lower than those of sea water in hydrothermal sediments there is no doubt that i and br contents of the fluids are influenced by hydrothermal alteration of the sediments and their organic c but signals are not clear the present study provides an overview of previous dsdp and odp studies of halide distributions in sedimentary pore waters in addition to other contributions on halide distributions in sedimentary pore waters in this symposium volume

escalating co2 degassing at the pisciarelli fumarolic system and implications for the ongoing campi flegrei unrest abstract this short communication aims at providing an updated report on degassing activity and ground deformation variations observed during the ongoing 2012 2019 campi flegrei caldera unrest with a particular focus on pisciarelli currently its most active fumarolic field we show that the co2 flux from the main pisciarelli fumarolic vent referred as soffione has increased by a factor 3 since 2012 reaching in 2018 2019 levels 600 tons day that are comparable to those typical of a medium sized erupting arc volcano a substantial widening of the degassing vents and bubbling pools and a further increase in co2 concentrations in ambient air up to 6000 ppm have also been detected since mid 2018 we interpret this escalating co2 degassing activity using a multidisciplinary dataset that includes thermodynamically estimated pressures for the source hydrothermal system seismic and ground deformation data from this analysis we show that degassing deformation and seismicity have all reached in 2018 2019 levels never observed since the onset of the unrest in 2005 with an overall uplift of 57 cm and 448 seismic events in the last year the calculated pressure of the campi flegrei hydrothermal system has reached 44 bar and is rapidly increasing our results raise concern on the possible evolution of the campi flegrei unrest and reinforce the need for careful monitoring of the degassing activity at pisciarelli hopefully with the deployment of additional permanent gas monitoring units

nature and origin of sedimentary clasts associated with mud volcanoes in the nile deep sea fan relationships with fluid venting abstract during the last 10 years several marine geological geophysical surveys conducted on the nile deep sea fan have provided much new information about the large fluid seepage phenomenon which characterizes this passive margin segment among the data more than 60 sediment cores have been recovered in this area rock clasts were collected from eight of them as well as during deep sea dives notably in the area of isis osiris and amon mud volcanoes in few areas especially in the western and the north eastern provinces of the nile fan some clasts consist of crust fragments resulting from cementation of muddy sediment by precipitation of high mg calcite these clasts correspond to a simple cementation of the mud by precipitation of high mg calcite as a consequence no obvious textural or faunal difference with the ambient matrix mud can be observed these clasts are made of autochthonous crusts derived from microbial anaerobic oxidation of methane and release of bicarbonate and sulphide in the surrounding pore water these clasts also lack aragonite in most of the other cases menes caldera isis osiris and amon mud volcanoes allochthonous clasts characterized by low mg calcite cement siderite or dolomite mixed with expelled mud outcrop on the seafloor nannofossils have allowed us to date some of these clasts most of the ages range from pliocene to pleistocene one clast is lower cretaceous in age the lithological facies often indicate coastal or deltaic environments some clasts are closely linked to an evaporite rich environment halite gypsum and analcime they all provide useful information on the nature of buried sedimentary series covering the margin their presence on the seafloor is due to the expulsion of a pressurized mixture of sediment water and gas this process is believed to have used pre existing tectonic conduits

the behaviour of zirconium hafnium and rare earth elements during the crystallisation of halite and other salt minerals abstract halite crystals from messinian and tortonian evaporites from sicily and spain and current precipitated halite crystals and the relative parent brines active evaporation systems were investigated in order to evaluate the zr hf and rare earth element ree behaviour halite crystallisation from evaporating brines fractionates zr hf and ree through a two step process during the first step dissolved complexes of studied elements are scavenged onto the surfaces of crystallising halite during the second step elements are co precipitated into the crystal lattice as it grows the first step mechanism is determined by the dissolved ree speciation in saltworks where carbonate ree complexes occur surface complexation of ree onto halite crystals does not occur on the contrary surface ree complexes onto halite crystals are forming in the dead sea water where aqueous ree speciation is dominated by chloride complexes under the latter conditions halite crystallises with cubic and cubic octahedral composite habitus octahedral planes involve the formation of strong coulombic interactions mainly with hf h 2 o 3 oh 5 rather than with zr h 2 o 4 oh 4 0 complexes as a consequence newly formed halite in the dead sea shows strong subchondritic zr hf ratios based on these indications analyses carried out on salt minerals from messinian and tortonian evaporites in sicily and spain show that their overall ree content can be considered a discriminating parameter between authigenic minerals and diagenetic modified materials however features of shale normalised ree patterns are driven by the mineralogical composition of evaporites rather than their authigenic or secondary nature on the contrary the zr hf signature of salt minerals is influenced by their origin indeed subchondritic zr hf values are found in primary salt minerals whereas larger zr hf values are recognised in those diagenetically modified calculated distribution coefficients of zr hf and ree are employed for modelling the ree distribution in halite equilibrated with the deep sea brines from typo medee and thetis basins eastern mediterranean the obtained indications allow us to discriminate brines formed by dissolution of evaporites relative to those representing relics of fossil evaporated seawater

focal mechanisms of recent seismicity at campi flegrei italy abstract the present study analysed volcano tectonic earthquakes that occurred in the caldera of campi flegrei italy from 2000 to 2019 to compute source focal mechanisms we used data from a large number of seismic stations to estimate reliable fault plane solutions for 71 events of a maximum duration magnitude md ranging between 0 5 md 2 5 we found that most solutions were of a normal type and were rake angle negative focal mechanisms in 86 of the cases only a few earthquakes occurred on normal dip slip faults the majority occurred on varying degrees of oblique slip only one event had a pure reverse mechanism and it was located far from the caldera centre the spatial distribution of the computed mechanisms exhibited a remarkable mix of fault orientations without any relationship to the location area or source depth the predominance of normal kinematics on high angle and nearly vertical faults and the very shallow source depth exhibited good agreement with the fact that seismicity at campi flegrei occurred during periods of ground uplift in fact ground uplift elongated the shallowest crust thus reducing the normal stress on existing locked faults this facilitated earthquakes particularly those characterised by normal dip slip and strike slip mechanisms in contrast ground subsidence produced a horizontal shortening of the upper crust which increased the normal stress on high angle faults and reduced earthquake occurrence our results indicate that the driving force of the recent volcano tectonic seismicity in the study region is the ongoing ground uplift

using 81kr and noble gases to characterize and date groundwater and brines in the baltic artesian basin on the one million year timescale abstract analyses for 81 kr and noble gases on groundwater from the deepest aquifer system of the baltic artesian basin bab were performed to determine groundwater ages and uncover the flow dynamics of the system on a timescale of several hundred thousand years we find that the system is controlled by mixing of three distinct water masses interglacial or recent meteoric water 18 o 10 4 with a poorly evolved chemical and noble gas signature glacial meltwater 18 o 18 with elevated noble gas concentrations and an old high salinity brine component 18 o 4 5 90 g cl l with strongly depleted atmospheric noble gas concentrations the 81 kr measurements are interpreted within this mixing framework to estimate the age of the end members deconvoluted 81 kr ages range from 300 ka to 1 3 ma for interglacial or recent meteoric water and glacial meltwater for the brine component ages exceed the dating range of the atta 3 instrument of 1 3 ma the radiogenic noble gas components 4 he and 40 ar are less conclusive but also support an age of 1 ma for the brine based on the chemical and noble gas concentrations and the dating results we conclude that the brine originates from evaporated seawater that has been modified by later water rock interaction as the obtained tracer ages cover several glacial cycles we discuss the impact of the glacial cycles on flow patterns in the studied aquifer system

inflation predictable behavior and co eruption deformation at axial seamount deformation of the ground surface at active volcanoes provides information about magma movements at depth improved seafloor deformation measurements between 2011 and 2015 documented a fourfold increase in magma supply and confirmed that axial seamount s eruptive behavior is inflation predictable probably triggered by a critical level of magmatic pressure a 2015 eruption was successfully forecast on the basis of this deformation pattern and marked the first time that deflation and tilt were captured in real time by a new seafloor cabled observatory revealing the timing location and volume of eruption related magma movements improved modeling of the deformation suggests a steeply dipping prolate spheroid pressure source beneath the eastern caldera that is consistent with the location of the zone of highest melt within the subcaldera magma reservoir determined from multichannel seismic results

sequence of thrusting and syntectonic sedimentation in the eastern sub atlas thrust belt dades and mgoun valleys morocco a series of balanced cross sections across the sub atlas thrust belt and the northern ouarzazate basin are used to illustrate the structural geometry and the timing of deformation at the southern front of the high atlas mountains of morocco the selected area is among the best sedimentary records of mountain building of the entire orogenic system the study of the relationships between thrusts and synorogenic continental formations enables the unraveling of kinematic sequences and the proposal of a relative chronology of deformation active thrusting in the area occurred in a rather continuous fashion from the oligocene to the pliocene punctuated by a major erosional phase imprecisely placed in late oligocene to early miocene times detrital sedimentary facies indicate that uplift in the hinterland of the high atlas to the north of the sub atlas belt was taking place already by mid eocene times although it might have commenced locally even earlier within the sub atlas zone the exposed faults did not propagate in a simple piggy back fashion but show evidence of a complex synchronous sequence with events of fault reactivation and out of sequence thrusting

evidence of thermal driven processes triggering the 2005 2014 unrest at campi flegrei caldera abstract an accelerating process of ground deformation that began 10 years ago is currently affecting the campi flegrei caldera the deformation pattern is here explained with the overlapping of two processes short time pulses that are caused by injection of magmatic fluids into the hydrothermal system and a long time process of heating of the rock the short pulses are highlighted by comparison of the residuals of ground deformation fitted with an accelerating polynomial function with the fumarolic co 2 ch 4 and he ch 4 ratios which are good geochemical indicators of the arrival of magmatic gases the two independent datasets show the same sequence of five peaks with a delay of 200 days of the geochemical signal with respect to the geodetic signal the heating of the hydrothermal system which parallels the long period accelerating curve is inferred by temperature pressure gas geoindicators referring to a recent interpretation that relates variations in the fumarolic inert gas species to open system magma degassing we infer that the heating is caused by enrichment in water of the magmatic fluids and by an increment in their flux heating of the rock caused by magmatic fluids can be a central factor in triggering unrest at calderas

a first gps measurement of vertical seafloor displacement in the campi flegrei caldera italy abstract this study shows how the gps technique can be utilized for seafloor displacement measurements and improved the survey control infrastructure in campi flegrei caldera two thirds of which is submerged under the sea in the gulf of pozzuoli about 2 5 km from the coast where the sea depth is 97 m a continuous gps station cfb1 has been installed since the end of 2011 on the top of a elastic beacon buoy rigidly connected by a steel cable to the ballast on the sea bottom we investigate the use of gps data to estimate the vertical displacement of the seafloor under the buoy the gps data were processed in kinematic mode and the vertical component of the measurements was corrected for the errors due to the horizontal motion of the buoy induced by wind and sea currents we report here the results for approximately 17 months of continuous gps data acquisition and we show for the first time a measure of vertical displacement of the seabed in the gulf of pozzuoli from january 2012 to may 2013 the seafloor uplifted by about 3 4 cm the similarity of the pattern of the cfb1 time series compared to the permanent gps stations of the nevocgps network located onshore is remarkable evaluation of the pearson s correlation coefficient between these stations and cfb1 indicates that the stations are measuring the same phenomenon this result is important because all models of evolution of bradyseism in the campi flegrei caldera are based on the interpretation of measures only on the emerged part of the caldera without use of any measures to date in the gulf of pozzuoli the methodology shown in this paper is reliable over time and economical compared to other systems of measurement of marine geodesy the major limitation is the depth of the sea confining this technique to the shallow water up to 100 m depth however a large part of the submerged campi flegrei caldera is shallower than 100 m so geodetic monitoring by means of gps buoys at several sites in the gulf of pozzuoli would allow to extend interpretative models to the entire caldera submerged and emerged

relics of evaporated sea water in deep basins of the eastern mediterranean abstract reexamination of data on hypersaline bottom brines from the deep anoxic tyro and bannock basins in the eastern mediterranean reveals that despite their similar chlorinity 6 0 mole kg h 2 o their chemical composition is significantly different the brine in the tyro basin has a na chloride composition na cl 1 with conspicuously low ratios of conservative elements to chloride br cl 2 4 10 4 li cl 1 4 10 5 b cl 1 6 10 4 indicating dissolution of halite in contrast brines from the bannock basin are characterized by an mg chloride signature na cl 0 78 with relatively high ratios of conservative elements to chloride br cl 1 7 10 3 li cl 5 2 10 5 b cl 8 4 10 4 the contents of na mg k li cl br and b in the deep bannock brines brine ii are identical to those in evaporated sea water of a degree of evaporation of 12 13 whereas ca is enriched and so 4 is depleted in contrast to previous studies it is suggested that brine ii from the bannock basin is a relic of ancient evaporated sea water that was slightly modified by sulphate reduction and gypsum dissolution the interstitial ancient evaporated sea water was liberated and accumulated on the sea floor probably during the formation of the deep basins in the bannock area

gypsum precipitation from cold brines in an anoxic basin in the eastern mediterranean in 1968 hot brines from which gypsum had precipitated were discovered in the red sea in a divergent plate boundary setting with hydrothermal activity1 we now report the discovery of cold brines in an entirely different geodynamic situation a convergent plate boundary in the eastern mediterranean where the heatflow is very low2 and no hydrothermal activity occurs decimetric pure gypsum crystals precipitate from the cold brines which occupy the bottom of a rimmed anoxic basin near the southern edge of the mediterranean ridge close to the sirte abyssal plain nucleation of the crystals does not occur at the surface but from the deep brines because the salinity of the water is normal down to the depth of 3 000 m we propose the name bacino bannock for this basin after the consiglio nazionale delle ricerche r v bannock from which the bottom water brines were surveyed and sampled

crustal shortening and vertical strain partitioning in the middle atlas mountains of morocco the ne sw trending middle atlas mountains of morocco are obliquely oriented within the late cenozoic regional stress field resulting in deformation that is partitioned into strike slip faulting and thrust related folding in the central middle atlas thrusting is confined to a 20 km wide fold belt between two relatively rigid crustal blocks that are obliquely converging we suggest that in addition to strain partitioning observed in plan view a partitioning of deformation between the upper and lower crust may be necessary to reconcile estimated crustal thickening and horizontal shortening within the fold belt cross section balancing based on field observations demonstrates a relatively modest amount of cenozoic horizontal shortening 4 7 km normal to the fold belt producing 800 m of structural relief yet geophysical data suggest this contraction has not produced a significant crustal root beneath the fold belt that is the belt does not appear to be isostatically compensated assuming all horizontal shortening was accommodated by crustal thickening beneath the fold belt implies much greater thickening than is suggested by constraints on the preshortened crustal thickness it thus appears that thickening does not accommodate all of the contraction we suggest one possible solution the upper crust shortens by thickening faulting and folding whereas the lower crust deforms laterally

high rate gps data on active volcanoes an application to the 2005 2006 mt augustine alaska usa eruption volcanic eruptions are usually preceded by measurable signals of growing unrest the most evident of which are the increase in seismicity and ground deformation it is also important to identify precursors of a possible renewal of the volcanic activity and to distinguish between an eruptive activity characterized by an intrusion with the related destructive power and a migration of magma stored in the main conduits the 2005 2006 eruption at mt augustine alaska usa is a good example of a massive migration of magmatic fluids from depth about 1 km b s l under the effect of gas overpressure the movements recorded by high rate gps hrgps data 15 s of sampling and processing rate from the stations deployed on the volcano define the dimensions and the characteristics of the shallow plumbing system in this study we propose a model of the different stages preceding the effusive phase the precursory phase where gas overpressure in the body of the volcano opens the terminal conduit

chloride bromide δ11b systematics of a thick clay rich aquitard system boron cl and br concentrations and boron isotopic compositions 11b were used to provide insight into the sources and water sediment interactions of fossil water in a thick nonfractured aquitard system in saskatchewan canada the aquitard system consists of 80 m of late pleistocene clay rich till disconformably overlying 77 m of late cretaceous marine clay the clay is underlain by a regional sand aquifer variations in cl and br confirmed the presence of well defined conservative mixing relationships between four types of fluids present in the aquitard system 1 low cl water from the base of the fractured and oxidized till zone at 4 m depth 2 water characterized by an elevated cl peak 190 mg l at about 12 m 3 glacial meltwater present between 20 and 60 m depth and 4 more saline water cl up to 1000 mg l from the underlying cretaceous clay and sand aquifer glacial meltwater has low cl 11b 20 and cl br ratios 50 the low cl br ratio of the glacial meltwater is similar to that of modern inland precipitation which suggests that the br budget in the atmosphere 20 30 ka b p was similar to that of today and that br enrichment in the atmosphere may be a natural process the relatively low cl br ratio 150 and 11b values of the saline water in the sand aquifer 35 and 39 respectively and pore water in the cretaceous clay 25 6 and 32 6 respectively are not consistent with simple dilution of seawater but suggest dilution and modification of fifteenfold evaporated seawater with a low cl br and a high 11b value 39 this evaporitic seawater may have been entrapped in the cretaceous clay upon or after its deposition and subsequently flushed from the clay by fresher water we suggest that the refreshening process modified the original brine into na hco3 water type and extracted boron with 11b 39 from the adsorbed sites in contrast increase of cl in the upper section of the till the 12 m peak resulted in apparent depletion of dissolved boron and relative 11b enrichment which can be explained by adsorption processes the b 11b relationships can thus be used to trace water clay interactions in aquitard systems

a late cenozoic age for long wavelength surface uplift of the atlas mountains of morocco the atlas mountains have been uplifted by two mechanisms cenozoic thickening of the crust and thinning of the mantle lithosphere due to a buoyant thermal anomaly previously inferred by indirect criteria to have started some 15 ma because crustal shortening related uplift and mantle related uplift affect the topography at different spatial scales we use scattered direct surface evidence to clarify the palaeoelevation dynamics uplifted messinian shallow marine sediments in the

boron isotope geochemistry of salt sediments from the dongtai salt lake in qaidam basin boron budget and sources abstract dongtai salt lake in qaidam basin contains abundant boron and lithium resources and has the highest reserve of lithium found in the world but the origin of these resources is highly controversial in this study we carried out a detailed study on chemical compositions and boron isotope characteristics of salt sediments collected from a drill core in the dongtai salt lake the evaporite carbonate and silicate phases of the sediments show 11 b values of 6 4 to 2 2 17 3 to 0 5 and 14 6 to 2 8 respectively which suggest a non marine origin for the salt lake the variation of 11 b vs k identified the evolution process of the salt lake the geochemical hydrochemical signatures and the reserve estimation of boron resources approved the dominant sources of saline resources containing abundant b k and li from the inflowing nalenggele river the boron isotopic fractionation factors between evaporite and brine i e evaporite brine vary from 0 9869 to 0 9955 and the linear variation of evaporite brine vs li mg molar ratios reflects the boron isotopic fractionation during crystallization of the salts the positive correlation between 11 b and b in the carbonate phase reflects the ph control on the incorporation of boron into the carbonates and the equilibrium isotope fractionation follows the rayleigh isotope fractionation rule in a closed system the variation of 11 b values in the silicate phase behaved as an oscillating pattern and the more negative shift of 11 b values corresponds to the mudstone strata deposited under warm humid climate conditions indicating the influence of intensive weathering

geochemical constraints for the origin of thermal waters from western turkey the combined chemical composition b and sr isotopes and the basic geologic setting of geothermal systems from the menderes massif in western turkey have been investigated to evaluate the origin of the dissolved constituents and mechanisms of water rock interaction four types of thermal water are present 1 a na cl of marine origin 2 a na hco3 type with high co2 content that is associated with metamorphic rocks of the menderes massif 3 a na so4 type that is also associated with metamorphic rocks of the menderes massif with h2s addition and 4 a ca mg hco3 so4 type that results from interactions with carbonate rocks at shallow depths the na cl waters are further subdivided based on br cl ratios water from the cumali seferihisar and bodrum karaada systems are deep circulated seawater br cl sea water whereas water from canakkale tuzla br cl sea water are from dissolution of messinian evaporites good correlations between different dissolved salts and temperature indicate that the chemical composition of the thermal waters from non marine geothermal systems is controlled by 1 temperature dependent water rock interactions 2 intensification of reactions due to high dissolved co2 and possibly hcl gasses and 3 mixing with overlying cold groundwater all of the thermal water is enriched in b the b isotopic composition 11b 2 3 to 18 7 n 6 can indicate either leaching of b from the rocks or b oh 3 degassing flux from deep sources the large ranges in b concentrations in different rock types as well as in thermal waters from different systems suggest the water rock mechanism 87sr 86sr ratios of the thermal water are used to differentiate between solutes that have interacted with metamorphic rocks 87sr 86sr ratio as high as 0 719479 and carbonate rocks low 87sr 86sr ratio of 0 707864

seafloor deformation and forecasts of the april 2011 eruption at axial seamount the axial seamount submarine volcano exhibits an inflation deflation cycle comparable to similar volcanoes on land measurements of ocean bottom pressure document the entire inflation deflation cycle between eruptions at axial seamount in 1998 and 2011 and imply that the timing of submarine eruptions could be more predictable than that of their subaerial counterparts

boron isotope and geochemical evidence for the origin of urania and bannock brines at the eastern mediterranean effect of water rock interactions the origin of hypersaline brines from urania and bannock deep anoxic basins in the eastern mediterranean sea has been investigated by integrating geochemical data and boron isotopic ratios bottom brines from urania basin have chloride contents up to 4200 mmole kg h2o and a marine na cl ratio 0 87 all the other ionic ratios are different from the marine ratios and show a relative enrichment in ca k br and b and depletion in mg and so4 as normalized to the chloride ion the 11b values of the urania brines 11b 29 8 2 9 n 7 are lower than that of mediterranean seawater 39 the concentrations of cl and na which make up 95 of the total dissolved ions in molal units suggest that the urania brines were derived from eightfold evaporated seawater the relative enrichment of ca and depletion of mg and so4 reflect dolomitization gypsum precipitation and sulfate reduction processes which modified the original evaporated seawater while the brines were entrapped as interstitial waters in the sedimentary section of the mediterranean the relative enrichments of br b and k and the low 11b value of the urania brines suggest high temperatures interactions of the evaporated sea water with sediments mass balance calculations suggest that desorption of exchangeable b from the sediments 11b 20 modified the marine b isotopic composition of the original eightfold evaporated seawater potassium was also leached from clay minerals whereas br was contributed from degradation of organic matter in the sediments this is consistent with a thermal anomaly up to 45 c recorded at depth in the region of urania basin in contrast bottom brines and shallow interstitial fluids from bannock basin with low temperatures 15 c show marine 11b 11b 39 6 2 8 n 5 38 5 2 2 n 5 respectively and b cl ratios 7 10 4 the b isotope data confirm that the bannock brines were derived from twelvefold evaporated seawater we argue that the brines from both basins are relics of fossil evaporated seawater that was entrapped in late miocene sediments and accumulated in the deep basins of the mediterranean seafloor

origin and age of pore waters in an actively venting gas hydrate field near sado island japan sea interpretation of halogen and 129i distributions abstract a gas hydrate field with highly active venting of methane was recently found near sado island in the eastern japan sea piston cores were collected from active venting sites and nearby locations in the umitaka spur joetsu knoll area during two cruises in 2004 ut04 and 2005 ky05 08 we report here halogen concentrations and 129 i i ratios in pore waters associated with gas hydrates from these expeditions the strongly biophilic behavior of i and to a lesser degree of br together with the presence of the long lived iodine radioisotope 129 i allow evaluation of potential source materials for methane in gas hydrate systems depth profiles of all three halogens particularly the very rapid downward increases of br and i concentrations strongly suggest input of deep fluids enriched in br and i but the profiles also display the effects of gas hydrate formation and dissociation although the 129 i i ratios are modified by 129 i from seawater and sediments at shallow depth likely ratios of the deep fluids are estimated to be between 400 10 15 and 600 10 15 equivalent to a late oligocene to early miocene age ages in the active methane venting sites typically are closer to the old end of this range than those in the reference sites this age range suggests that the methane associated with venting and gas hydrate formation in this area is derived from organic materials accumulated during the initial opening of the japan sea the umitaka spur joetsu knoll gas hydrate field demonstrates the movement of deep fluids associated with the release of significant amounts of methane from the seafloor processes which might be important components of mass transfer and carbon cycle in the shallow geosphere

volcano monitoring using gps developing data analysis strategies based on the june 2007 kīlauea volcano intrusion and eruption 1 the global positioning system gps is one of the most common techniques and the current state of the art used to monitor volcano deformation in addition to slow several centimeters per year displacement rates gps can be used to study eruptions and intrusions that result in much larger tens of centimeters over hours days displacements it is challenging to resolve precise positions using gps at subdaily time intervals because of error sources such as multipath and atmospheric refraction in this paper the impact of errors due to multipath and atmospheric refraction at subdaily periods is examined using data from the gps network on k lauea volcano hawai i methods for filtering position estimates to enhance precision are both simulated and tested on data collected during the june 2007 intrusion and eruption comparisons with tiltmeter records show that gps instruments can precisely recover the timing of the activity

effective resolution and drift of paroscientific pressure sensors derived from long term seafloor measurements 1 starting with the installation of the noaa tsunami early warning system dart in 1983 the paroscientific digiquarz broadband depth sensor has been deployed for long term ocean bottom pressure measurements in numerous marine investigations the sensor turned out to be very reliable with a good signal repeatability within a broad measuring range and high resolution however up to now its long term drift noise level and effective resolution under in situ conditions at the seafloor are only known from a few published studies and for a few sensors in this study we analyze 118 long term seafloor pressure time series longer than 2 months and up to a maximum time period of 9 years to investigate effective resolution and long term drift under in situ conditions the data are from dart ifm geomar lolem and cork stations the noise level of the data and therefore the mean sensor resolution are lower than an upper threshold of 20 7 pa corresponding to 2 07 mm equivalent water level for stations installed directly on the seafloor the noise level of cork sensors is much larger with a median value of 127 pa long term sensor drift is assumed to be composed of an initial exponential part and a subsequent linear drift in situ mean drift is 0 88 0 73 kpa a determined from all available data with a slight increase of drift with deployment depth for the first time we are able to quantify effective pressure resolution and drift of the widely used paroscientific pressure gauges under in situ conditions our results provide important constrains for the interpretation of seafloor pressure records however in situ self calibration procedures for the paroscientific sensors are still needed in order to benefit from high effective resolution and long term stability and also to increase accuracy especially for the monitoring of geodynamic processes at the seafloor

potassium and boron co depletion in canadian shield brines evidence for diagenetic interactions between marine brines and basin sediments abstract hypersaline ca cl brines of marine origin deep within the crystalline rocks of the canadian shield are typically highly depleted in potassium and boron compared to their concentrated seawater parent brine while this depletion in both solutes is not accompanied by a major alteration in their original marine b k ratios their initial marine 11 b has been lowered to 20 30 values that are intermediate between that of present day seawater 39 and typical crustal values 3 5 together these observations eliminate 3 of 4 potential k and b removal mechanisms that may have operated at various times over the long history of shield brines 1 co precipitation in late stage evaporative salts in the marine basin where the brine was formed 2 incorporation in secondary feldspars formed either within basin sediments or the host rocks and 3 in situ adsorption by secondary clay minerals on fracture surfaces rather the 11 b values together with the consistency in the depleted but similar k br and b br ratios suggest that k and b were removed from shield brines by fixation in illitic clay minerals this likely occurred during the diagenetic illitization of smectite in argillaceous marine sediments through which the brine infiltrated prior to penetrating the underlying crystalline basement rocks

boron isotope geochemistry of australian salt lakes boron isotope geochemistry has been investigated in brines groundwaters and sediments from the modern australian salt lakes of victoria south australia and western australia by applying negative thermal ionization mass spectrometry techniques the geochemical history of the brines has been reconstructed by using 11b bcl and nacl ratios the victorian volcanic crater lakes of southeastern australia have water salinities of up to 60 g l molar nacl ratios 0 87 similar to the marine ratio molar bcl ratios of 2 9 10 4 to 4 9 10 4 and 11b values of 54 to 59 relative to nbs 951 the depletion of total b and the high positive 11b values relative to seawater bclratio 7 9 10 4 11b 39 are attributed to a marine cyclic salt origin together with adsorption processes in closed systems with low water sediment wr ratios in contrast salt lakes from south australia and western australia which are large shallow playas associated with halite gypsum and detrital clay minerals have interstitial and surface brines characterized by salinities of 80 to 280 g l molar nacl ratios of 0 85 to 1 molar bcl ratios of 4 10 6 to 4 10 4 and 11 values of 25 to 48 the 11 values of these brines are different from those of groundwaters from the great artesian basin 11 15 9 to 2 2 with high molar bcl ratios of 1 10 3 to 3 8 10 2 country rocks 11b 8 7 to 6 8 and modern detrital sediments present in these salt lakes 11b 3 2 to 12 3 the 11b values of these salt lakes overlap with those of surface and brackish waters 11b 28 to 35 and with the b isotopic composition of seawater 11b 39 both low molar nacl ratios 39 of some brines indicate interaction of the brines with detrital sediments within the salt lake systems 11 values 39 suggest mixing of brines of marine origin from which b was partly removed by adsorption with waters of terrestrial origin with low 11 values nacl ratios are used as indicators of the origin of the salts as well as of halite dissolution precipitation the 11 values and bcl ratios are sensitive to a marine or non marine origin adsorption of boron onto clays and the effective water sediment ratio at low wr ratios the preferential removal of 10b from the solution affects the bulk solution whereas at high wr ratios the 11 value of a solution is not affected by adsorption although the 11 value of borate minerals may be a discriminant of marine or non marine origin boron isotopes are less distinctive in evaporative environments where boron is not an abundant component and where water sediment interaction occurs

temporal stability and origin of chemoclines in the deep hypersaline anoxic urania basin submarine brine lakes feature sharp and persistent concentration gradients between seawater and brine though these should be smoothed out by free diffusion in open ocean settings the anoxic urania basin of the eastern mediterranean contains an ultrasulfidic hypersaline brine of messinian origin above a thick layer of suspended sediments with a dual modeling approach we reconstruct its contemporary stratification by geochemical solute transport fundamentals and show that thermal convection is required to maintain mixing in the brine and mud layer the origin of the urania basin stratification was dated to 1650 years b p which may be linked to a major earthquake in the region the persistence of the chemoclines may be key to the development of diverse and specialized microbial communities ongoing thermal convection in the fluid mud layer may have important yet unresolved consequences for sedimentological and geochemical processes also in similar environments

paired deformation sources of the campi flegrei caldera italy required by recent 1980 2010 deformation history we analyze 1980 2010 ground displacements to discern similarities or differences between campi flegrei cf inflations and deflations and highlight possible anomalies in particular areas we show that the deformation pattern can be decomposed into two stationary constant over time except for a mere scaling factor parts both of them are satisfied by simple deformation sources a quasi horizontal elongated crack oriented nw to se and embedded in an elastic layered half space at a depth of about 3600 m satisfies large scale deformation all source parameters but potency volume change are constant over time residual deformation is confined to the area of the solfatara fumarolic field and satisfied by a small spheroid located at about 1900 m in depth again all source parameters but potency are constant over time the histories of the two sources are somewhat similar but not equal supporting the existence of a genuine local deformation source at solfatara against the emergence of a mere distortion of large scale deformation although reality is probably much more complex our simple model explains 1980 2010 cf deformation within ground displacement data errors and is consistent with solfatara geochemical conceptual models fumarolic geochemical data and seismic attenuation imaging of cf the observation that the cf deformation pattern can be decomposed into two stationary parts is hardly compatible with several recent works which proposed multiple sources with different features acting in different periods fluid injections implying ample changes of large scale deformation pattern over time complex spatio temporal patterns of distributions of volumetric sources