rapid releases of metal salts and nutrients following the deposition of volcanic ash into aqueous environments deposition of volcanic ash into aqueous environments leads to dissolution of adsorbed metal salts and aerosols increasing the bioavailability of key nutrients volcanogenic fertilization events could increase marine primary productivity leading to a drawdown of atmospheric co2 here we conduct flow through experiments on unhydrated volcanic ash samples from a variety of locations and sources measuring the concentrations and fluxes of elements into de ionized water and two contrasting ocean surface waters comparisons of element fluxes show that dissolution of adsorbed surface salts and aerosols dominates over glass dissolution even in sustained low ph conditions these surface ash leachates appear unstable decaying in situ even if kept unhydrated volcanic ash from recent eruptions is shown to have a large fertilization potential in both fresh and saline water fluorine concentrations are integral to bulk dissolution rates and samples with high f concentrations display elevated fluxes of some nutrients particularly fe si and p bio limiting micronutrients are released in large quantities suggesting that subsequent biological growth will be limited by macronutrient availability importantly acidification of surface waters and high fluxes of toxic elements highlights the potential of volcanic ash leachates to poison aqueous environments in particular large ph changes can cause undersaturation of caco3 polymorphs damaging populations of calcifying organisms deposition of volcanic ash can both fertilize and or poison aqueous environments causing significant changes to surface water chemistry and biogeochemical cycles

measuring volcanic plume and ash properties from space the remote sensing of volcanic ash plumes from space can provide a warning of an aviation hazard and knowledge on eruption processes and radiative effects in this paper new algorithms are presented to provide volcanic plume properties from measurements by the michelson interferometer for passive atmospheric sounding mipas the advanced along track scanning radiometer aatsr and spinning enhanced visible and infrared imager seviri a challenge of remote sensing is to provide near real time methods to identify and so warn of the presence of volcanic ash to achieve this a singular vector decomposition method has been developed for the mipas instrument on board the environmental satellite envisat this method has been applied to observations of the ash clouds from the eruptions of nabro and the puyehue cordon caulle in 2011 and lead to a more sensitive volcanic signal flag which was capable of tracking changes in the volcanic signal spectra as the plume evolved a second challenge for remote sensing is to identify the ash plume height this is a critical parameter for the initialisation of algorithms that numerically model the evolution and transport of a volcanic plume as mipas is a limb sounder the identification of ash also provides an estimate of height provided the plume is above about 6 km this is complemented by a new algorithm stereo ash plume height retrieval algorithm saphra that identifies plume height using the parallax between images provided by along track scanning radiometer type instruments the algorithm was tested on an image taken at 14 01 gmt on 6 june 2011 of the puyehue cordon caulle eruption plume and gives a height of 11 9 1 4 km which agreed with the value derived from the location of the plume shadow 12 7 1 8 km this plume height was similar to the height observed by mipas 12 1 5 km at 02 56 gmt on 6 june the quantitative use of satellite imagery and the full exploitation of high resolution spectral measurements of ash depends upon knowing the optical properties of the observed ash laboratory measurements of ash from the 1993 eruption of mt aso japan have been used to determine the refractive indices from 1 to 20 m these preliminary measurements have spectral features similar to ash values that have been used to date albeit with slightly different positions and strengths of the absorption bands the refractive indices have been used to retrieve ash properties plume height optical depth and ash effective radius from aatsr and seviri instruments using two versions of oxford ral retrieval of aerosol and cloud orac algorithm for aatsr a new ash cloud type was used in orac for the analysis of the plume from the 2011 eyjafjallajokull eruption for the first 500 km of the plume orac gave values of plume height 2 5 6 5 km optical depth 1 2 5 and effective radius 3 7 m which are in agreement with other observations a weakness of the algorithm occurs when underlying cloud invalidates the

descriptive nomenclature and classification of pyroclastic deposits and fragments recommendations of the iugs subcommission on the systematics of igneous rocks

a comparison of burial maturity and temperature histories of selected wells from sedimentary basins in the netherlands sedimentary basins in the netherlands contain significant amounts of hydrocarbon resources which developed in response to temperature and pressure history during mesozoic and cenozoic times quantification and modelling of burial maturity and temperature histories are the major goals of this study allowing for a better understanding of the general geological evolution of the different basins as well as petroleum generation all major basins in the netherlands encountered at least one time of inversion and therefore moderate to high amounts of erosion in order to determine the amount of inversion the basins have experienced a 1d study was performed on 20 wells within three basins west netherlands central netherlands and lower saxony basins new vitrinite reflectance values were obtained and existing data re evaluated to gain a good data base the burial histories of six wells two for each studied basin are presented here to demonstrate the differences in basin evolution that led to their present shape and petroleum potential the permo triassic subsidence phase can be recognized in all three basins but with varying intensity in the jurassic the basins experienced different relative movements that culminated in the cretaceous when the influence of the inversion caused erosion of up to 2 500 m most wells show deepest burial at present day whereas the timing of maximum temperature differs significantly springer verlag 2007

hydrocarbon reserves of gachsaran oilfield sw iran geochemical characteristics and origin abstract biomarkers and carbon isotope data were used to depict geochemical properties and to delineate source of the crude oils from asmari and bangestan reservoirs of the giant gachsaran oilfield sw iran despite the distinct horizons of the reservoirs and severe petrophysical heterogeneity inside each reservoir all oil samples show an identical level of thermal maturity furthermore similar source related parameters reflect identical source rock for both reservoirs they indicate carbonate marl source deposited in a marine environment under anoxic suboxic conditions strong marine organic matter signatures of predominantly algal origin along with evidence of a terrigenous angiosperm plant contribution were detected geochemical evidence suggests that the gachsaran field asmari and bangestan oils being sourced from a mix of organic rich kazhdumi and pabdeh source rocks of albian and middle eocene early oligocene ages respectively carbon isotope composition and v ni ratio signatures indicate kazhdumi formation as the main source rock meanwhile significant presence of oleanane and less than unity values of c 29 c 30 hopanes ratio demonstrate a partial contribution of pabdeh formation this contradiction could be explained by two scenarios 1 incorporating very immature non expelled pabdeh oils into the mature kazhdumi oils during migration or 2 partial charge form low maturity pabdeh oils that is insufficient to impact a typical mixed signature over the geochemical fingerprint of the reservoired oils additionally geochemical similarities give rise to an assumption of reservoir and trap inter connection for this giant field

2d basin modeling study of the binak trough northwestern persian gulf iran abstract the northwestern part of the persian gulf is one of the most prominent hydrocarbon exploration and production areas oilfields are located in structural highs formed around the cenomanian depression known as binak trough to evaluate the highly variable source rock maturity timing of hydrocarbon generation as well as migration pattern and the remaining hydrocarbon potential of the early cretaceous source rocks burial and thermal histories were constructed for four production wells and one pseudo well in addition two cross sections covering the depression and the structural highs around the trough were investigated by 2d basin modeling to provide a better regional overview on basin evolution the modeling results indicate that whereas the cretaceous source rocks are immature or early mature at the location of oilfields they reached sufficient maturity to generate and expel considerable amounts of hydrocarbons in the binak depression the main phase of oil generation and expulsion from the cretaceous source rocks is relatively recent and thus highly favorable for the conservation of hydrocarbon accumulations trap charging occurred through the late miocene to pliocene after the zagros folding 2d models predict that the albian source rock still has significant hydrocarbon generation potential whereas the lower neocomian source rock has reached already a high transformation ratio within the deep kitchen area oil migration occurs in both lateral and vertical directions this migration pattern could explain the distribution of identified oil families in the northwestern part of the persian gulf

regional stratigraphy of the zagros fold thrust belt of iran and its proforeland evolution the latest neoproterozoic through phanerozoic stratigraphy of the zagros fold thrust belt of iran has been revised in the light of recent investigations the revised stratigraphy consists of four groups of rocks each composed of a number of unconformity bounded megasequences representing various tectonosedimentary settings in the lowest group ranging in age from latest precambrian to devonian the uppermost neoproterozoic to middle cambrian rocks constitute a megasequence of evaporites siliciclastic deposits and interlayered carbonates which were deposited in pull apart basins that developed by the najd strike slip fault system this megasequence is overlain by a second one middle to late cambrian in age which consists of shallow marine siliciclastic and carbonate rocks representing deposition in an epicontinental platform the overlying shales siltstones and partly volcanogenic sandstones of ordovician silurian and devonian age are local remnants of stratigraphic units that were extensively eroded during development of several major unconformities the second group consists of two megasequences one permian and the other triassic composed of widespread transgressive basal siliciclastic rocks and overlying evaporitic carbonates of an equatorial epi pangean very shallow platformal sea the third group is composed of four megasequences formed of shallow and deep water carbonates with some siliciclastic and evaporite deposits which accumulated on a neo tethyan continental shelf during earliest jurassic through late turonian time the fourth group comprises siliciclastic and carbonate deposits of a largely underfilled nw to se trending forward and backward migrating late cretaceous to recent proforeland basin which has evolved as an integral part of the zagros orogen this last group consists of three megasequences ix x and xi with distinctive lateral and vertical facies variations which reflect specific tectonic events megasequence ix comprises uppermost turonian to middle maastrichtian prograding and retrograding siliciclastic and carbonate deposits whose accumulations reflect emplacement obduction of ophiolite slivers and subsequent collisional events in the zagros orogen megasequence x consists of uppermost maastrichtian to upper eocene siliciclastic and carbonate rocks which deposited first progradationally in front of the zagros orogenic wedge with reduced contractional tectonic activity and then retrogradationally due to intensified thrust stacking in the interior parts of the orogen megasequence xi consists of oligocene and lower miocene carbonate strata deposited retrogradationally shortly after a period of intensified late eocene thrust faulting in the deformational wedge and an overlying succession of upward coarsening northeasterly derived siliciclastic deposits of lower miocene to recent age which are composed of erosional byproducts of the southwest vergent zagros thrust sheets

thermal history and source rock characterization of a paleozoic section in the awbari trough murzuq basin sw libya abstract in some areas of the murzuq basin sw libya the lower silurian member comprises highly radioactive shales hot shale which are regarded as the most significant factor controlling petroleum generation in the basin in this context it was the goal of our project to study the distribution and maturity of the hot shale in the framework of basin evolution organic geochemical organic petrological and basin modelling methods were used to obtain a more thorough understanding four wells from the northern and central part of the awbari trough have been selected for this study the hot shale contains mainly type ii kerogen with high toc values ranging from 3 to 23 which is considered as an indication for excellent source rock potential a good petroleum potential is further supported by hydrogen indices varying between 220 and 380 mg hc g toc numerical 1d basin modelling was performed for four wells in order to assess the thermal maturity of the tanezzuft hot shale and its evolution through time mean random equivalent vitrinite reflectance results using vitrinite like particles for lower silurian hot shale pyrolysis t max values and fluorescence colours indicate that the hot shale is immature to early mature in the southern part and clearly more mature in the northern part of the basin other potential source rocks from silurian tanezzuft middle upper devonian awaynat wanin and lower carboniferous marar formations were analysed thermal history modelling indicates that the present day geothermal gradients and heat flows vary at different locations but that paleotemperature evolution is mostly related to deepest burial peak temperatures were reached either in the late carboniferous before hercynian uplift occurred or in the jurassic cretaceous the latter scenario being more probable because much oil has been preserved

coalification pattern and thermal modelling of the permo carboniferous saar basin sw germany abstract palaeo heat flow values and thicknesses of eroded permo carboniferous sediments in the saar basin were evaluated using one dimensional thermal modelling techniques thermal burial and erosion histories for 16 wells were calibrated by comparing measured and calculated vitrinite reflectance using the kinetic easy r o algorithm and by comparing measured and calculated temperature data on the basis of 37 wells coalification maps were constructed revealing a syn kinematic coalification pattern thermal maturity of the sediments can only be explained by deep burial and moderate heat flows during time of maximum burial i e in the permo carboniferous calculated heat flow data range between 50 and 75 mw m 2 which implies a crustal thickness between 30 and 40 km during the time of maximum burial these values are in accordance with the geodynamic setting of the basin the influence of the permo carboniferous volcanism on the palaeo temperature distribution was overwhelmed by the subsequent deep burial during permian times between 1800 and 3000 m of permo carboniferous sediments were eroded different sedimentation and erosion histories are characteristic for anticlines and synclines respectively

composition resolved size distributions of volcanic aerosols in the mt etna plumes 1 particle size distributions for soluble and insoluble species in mt etna s summit plumes were measured across an extended size range 10 nm d 100 m using a combination of techniques automated scanning electron microscopy qemscan was used to chemically analyze many thousands of insoluble particles collected on pumped filters allowing the relationships between particle size shape and composition to be investigated the size distribution of fine silicate particles d 10 m was found to be lognormal consistent with formation by bursting of gas bubbles at the surface of the magma the compositions of fine silicate particles were found to vary between magmatic and nearly pure silica this is consistent with depletion of metal ions by reactions in the acidic environment of the gas plume and vent measurements of the size shape and composition of fine silicate particles may potentially offer insights into preemission synemission and postemission processes the mass flux of fine silicate particles from mt etna released during noneruptive volcanic degassing in 2004 and 2005 was estimated to be 7000 kg d 1 analysis of particles in the range 0 1 d m 100 by ion chromatography shows that there are persistent differences in the size distributions of sulfate aerosols between the two main summit plumes analysis of particles in the range 0 01 m d 0 1 m by scanning transmission electron microscopy stem shows that there are significant levels of nanoparticles in the mt etna plumes although their compositions remain uncertain

atmospheric chemistry of an antarctic volcanic plume 1 we report measurements of the atmospheric plume emitted by erebus volcano antarctica renowned for its persistent lava lake the observations were made in december 2005 both at source with an infrared spectrometer sited on the crater rim and up to 56 km downwind using a twin otter aircraft with the two different measurement platforms plume ages were sampled ranging from 1 min to as long as 9 h three species co carbonyl sulfide ocs and so2 were measured from both air and ground while co and ocs were conserved in the plume consistent with their long atmospheric lifetimes the downwind measurements indicate a so2 co ratio about 20 of that observed at the crater rim suggesting rapid chemical conversion of so2 the aircraft measurements also identify volcanogenic h2so4 hno3 and recognized for the first time in a volcanic plume ho2no2 we did not find nox in the downwind plume despite previous detection of no2 above the crater this suggests that near source nox was quickly oxidized to hno3 and ho2no2 and probably no3 aq possibly in tandem with the conversion of so2 to sulfate these fast processes may have been facilitated by cloud processing in the dense plume immediately downwind from the crater a further striking observation was o3 depletion of up to 35 in parts of the downwind plume this is likely to be due to the presence of reactive halogens bro and clo formedthrough heterogeneous processes in the young plume our analysis adds to the growing evidence for the tropospheric reactivity of volcanic plumes and shows that erebus volcano has a significant impact on antarctic atmospheric chemistry at least locally in the southern ross sea area

magnetostratigraphy of miocene pliocene zagros foreland deposits in the front of the push e kush arc lurestan province iran abstract the timing of the deformation in the zagros simply folded belt is poorly constrained because of the lack of an accurate absolute chronology of the syntectonic sedimentary sequences the foreland basin infill at the front of the push e kush arc is composed of fine grained fluvial plain deposits agha jari fm and coarse conglomerates at the top of the section bakhtyari fm a magnetostratigraphic study was carried out in a composite section spanning about 2800 m in order to date growth strata and to constrain the timing of the deformation in the mountain front flexure mff magnetostratigraphic correlation of the base of the agha jari fm with chron c5a yields an age of 12 8 to 12 3 ma for this base the transition to the conglomerates of the bakhtyari fm correlates with the upper gauss chron c2an at approximately 3 ma the deposition age of the top of the preserved bakhtyari fm is extrapolated around the pliocene pleistocene boundary the base of the agha jari fm growth strata and thus the beginning of the deformation in the front of the push e kush arc is dated at 8 1 7 2 ma the topmost preserved bakhtyari is folded in the ne flank of the changuleh anticline and is unconformably overlying the sw flank of the anaran anticline this indicates that the tectonic deformation in the front of the push e kush arc was active at least during 5 my the mff is a relatively long lived structure active from 8 1 to 7 2 ma to about the pliocene pleistocene boundary partly synchronous with the changuleh anticline to the foreland after mff tectonic cessation only the changuleh anticline remained active

capturing volcanic plumes in 3d with uav based photogrammetry at yasur volcano vanuatu abstract as a precise volume of volcanic ash plume is essential to understand the dynamic of gas emission exchanges and the eruptive dynamics we have measured in 3d using photogrammetry a small size volcanic plume at the summit of yasur volcano vanuatu the objective was to collect the altitude and planform shape of the plume as well as the vertical variations of the shape and size to reach this objective the authors have used the structure from motion photogrammetric method applied to a series of photographs captured in a very short period of time around and above the plume a total of 146 photographs at 3000 4000 pixel were collected as well as the geolocation the pitch tilt and orientation of the cameras the results revealed a mushroom like shape of the plume with a narrow ascending column topped by a turbulent mixing zone the volume of the plume was calculated to be 13 430 m3 512 m3 with the error being the cube of the linear error from the ground control points for a maximum height above the terrain of 63 m the included error was also kept high because of the irregular distribution of the ground control points that could not be collected in dangerous areas due to the ongoing eruption based on this research it is therefore worth investigating the usage of multiple cameras to capture plumes in 3d over time and the method is also a good complement to the recent development of photogrammetry from space which can tackle larger scale eruption plumes

optical modeling of volcanic ash particles using ellipsoids the single scattering properties of volcanic ash particles are modeled here by using ellipsoidal shapes ellipsoids are expected to improve the accuracy of the retrieval of aerosol properties using remote sensing techniques which are currently often based on oversimplified assumptions of spherical ash particles measurements of the single scattering optical properties of ash particles from several volcanoes across the globe including previously unpublished measurements from the eyjafjallajokull and puyehue volcanoes are used to assess the performance of the ellipsoidal particle models these comparisons between the measurements and the ellipsoidal particle model include consideration of the whole scattering matrix as well as sensitivity studies on the point of view of the advanced along track scanning radiometer aatsr instrument aatsr which flew on the envisat satellite offers two viewing directions but no information on polarization so usually only the phase function is relevant for interpreting its measurements as expected ensembles of ellipsoids are able to reproduce the observed scattering matrix more faithfully than spheres performance of ellipsoid ensembles depends on the distribution of particle shapes which we tried to optimize no single specific shape distribution could be found that would perform superiorly in all situations but all of the best fit ellipsoidal distributions as well as the additionally tested equiprobable distribution improved greatly over the performance of spheres we conclude that an equiprobable shape distribution of ellipsoidal model particles is a relatively good yet enticingly simple approach for modeling volcanic ash single scattering optical properties

magmatic structures in the tuolumne intrusive suite california a new model for the formation and deformation of ladder dikes understanding the growth and differentiation of silicic magma chambers is a central issue in volcanology we use field observations of meter scale ladder dikes from the tuolumne intrusive suite tis california usa together with analogue experiments and scaling theory to demonstrate that prior to solidification these features are deformed and broken by shearing motions in the magma chamber from field observations the majority of the ladder dikes are 1 exposed perpendicular to gravity in a nearly horizontal slice through a solidified magma chamber 2 located near a contact specifically where they occur in large clusters with either host rock or another intrusive unit in the tis and 3 oriented roughly perpendicular to that contact the ladder dikes show evidence of breakup at the meter scale as well as at the centimeter scale mafic felsic banding we hypothesize that the ladder dikes are buoyant plumes in a stirred magma chamber in particular their orientation and deformation are related to their rise or descent velocity the stirring velocity within the chamber and the rheological contrast between the plume and ambient material the comparison between field data and laboratory experiments suggests that most of the ladder dikes deformed in a regime dominated by breakup from yielding under tension

source rock distribution and maturation in the zagros orogenic belt provenance of the asmari and bangestan reservoir oil accumulations abstract the zagros orogenic belt of iran is one of the most prolific petroliferous areas accounting for approx 12 of proven global reserves correlation techniques reveal that a majority of the oils variously reservoired in asmari oligo miocene and bangestan group upper cretaceous anticlinal structures share a common provenance oils of the n e khuzestan fields are an exception showing a conspicuously different origin candidate source potential for the crucial central zagros embayment and contiguous areas was assessed on field survey and from well materials collected during the decade from 1968 onwards although varying locally in vertical and lateral distribution attractive sources occur throughout the section included were silurian shales the sargelu middle jurassic garau gadvan lower cretaceous kazhdumi albian gurpi upper cretaceous and pabdeh paleogene fms maturation of these source units was essentially controlled by the foredeep subsidence related to the zagros orogeny being a neogene event hydrocarbon generation and migration are very recent and essentially synorogenic consolidation of this information with the real distribution of candidate sources application of carbon isotope based source oil assignments and biomarker results successfully differentiated the provenance of the generic oil groupings over much of khuzestan the kazhdumi was recognised as the major contributor elsewhere the pabdeh fm yields isotopically distinctive oils in n e khuzestan evaluation of this basin allowed identification of prolific source rocks in low energy euxinic argillaceous lime mudstones similarly it provided an early application of pyrolysis techniques carbon isotopic correlations and subsidence history maturation migration modelling approaches now routinely employed in basin evaluation

combined use of seviri and modis for detecting measuring and monitoring active lava flows at erupting volcanoes multispectral data acquired by spinning enhanced visible and infrared imager seviri onboard the geostationary platform meteosat second generation msg2 located at 0deg longitude were analyzed to assess the payload suitability for quantitative volcano monitoring in times of good infrared transparency of the troposphere seviri data proved particularly suited to detect the onset of effusive eruptions and to monitor the related lava flows with 15 min refresh rates after development of a code allowing for fast automated processing of the 96 data streams downlinked daily by msg2 thorough monitoring tests were carried out on the 2007 eruptions of stromboli aeolian islands italy and piton de la fournaise reunion island france the results in radiant flux and effusion rate provided by use of thermal mid and short infrared bands of seviri were validated by exploiting simultaneous modis overpasses by terra and aqua up to four times daily

retrieval of microphysical and morphological properties of volcanic ash plumes from satellite data application to mt ruapehu new zealand a quantitative analysis of the properties of several mt ruapehu new zealand ash plumes has been performed using multispectral satellite data from the avhrr 2 and atsr 2 instruments the analysis includes identification of the plume from background clouds using the reverse absorption effect in the thermal channels modelling and retrieval of particle sizes determination of the plume height from cloud shadows stereoscopy and meteorological data and estimates of the mass of fine particles radii less than 10 m a new spectral technique for identifying opaque silica rich ash clouds is demonstrated by utilizing the near infrared 1 6 m and visible 0 67 m channels of the atsr 2 and the optical properties of a simple volcanic cloud are presented for use in radiative transfer studies it is found that the ruapehu eruption cloud contained silica rich ash particles with radii generally less than a few micrometres the distribution of fine particles is monomodal with a dominant mode peak of about 3 m radius mass loadings of fine particles are found to be in the range 1 to 7 mg m 3 and are consistent with estimates of mass loadings of volcanic clouds from eruptions of other volcanoes the height of the plume top derived from radiosonde data and plume top temperatures in the opaque regions was found to be between 7 5 and 8 5 km while the plume thickness was estimated to be between 1 5 and 3 km cloud height derived from atsr 2 stereoscopy on a different plume gave heights in the range 5 to 8 km the results of this study provide important information on the optical properties of nascent volcanic eruption plumes this information may prove useful in determining the potential effects of volcanic clouds on local climate and in assessing any hazard to aviation

time and temperature in petroleum formation application of lopatin s method to petroleum exploration n v lopatin in the soviet union has developed a method for taking both time and temperature into account as factors in thermal maturation of kerogen lopatin s time temperature index of maturity tti values correlate with the thermal regimes corresponding to generation and preservation of hydrocarbons because such information is potentially of great interest for oil exploration a calibration and evaluation have been made of lopatin s method within the limitations of the data presently available the following statements can be made 1 the rate of the chemical reactions involved in thermal maturation of organic material appears to double with every 10 c 18 f rise in temperature 2 threshold values of lopatin s time temperature index of maturity tti are 15 onset of oil generation 75 peak oil generation 160 end oil generation 500 40 oil preservation deadline 1 000 50 oil preservation deadline 1 500 wet gas preservation deadline 65 000 dry gas preservation deadline 3 tti values calculated from lopatin reconstructions consistently agree with other maturation parameters commonly used by petroleum geochemists potential applications of lopatin s method for oil exploration include timing of oil generation calculation of volume of hydrocarbons generated within a basin and determination of economic deadlines

structural framework of the zagros fold thrust belt iran abstract data gleaned from the literature on the zagros have been compiled and used in conjunction with new interpretations to provide a better picture of the structures sedimentation history and deformation of this hydrocarbon rich mountain belt the belt parallel mountain front the n s trending kazerun izeh and e w trending bala rud fault zones are defined as the master structural elements of the belt these fault zones divide the zagros basin into zones with different stratigraphic successions and different rheological profiles this resulted in different structural styles developing along the belt during the subsequent collision the kazerun and izeh fault zones acted as the depositional system transition zone between the lurestan and fars regions in jurassic cretaceous time and partly controlled the distribution of the kazhdumi formation one of the major source rocks by the end of the cretaceous the nw se trending mountain front fault divided the present folded belt of the zagros into a major foreland basin to the southwest and a piggyback basin to the northeast activity along other major transfer fault zones including the izeh kazerun and bala rud fault zones occurred at this time and controlled the sedimentation and subsidence of the dezful embayment the main target region for hydrocarbon exploration these fault zones controlled the thickness of the asmari formation one of the main reservoirs and also the considerable thickness and facies changes of the gachsaran formation the major seal to the asmari formation the present morphology of the mountain belt is interpreted as being mainly related to the pinning of the mountain front fault to the northwest of the dezful embayment and to the north of the strait of hormuz

fine ash content of explosive eruptions abstract in explosive eruptions the mass proportion of ash that is aerodynamically fine enough to cause problems with jet aircraft or human lungs 50

reference data set of volcanic ash physicochemical and optical properties uncertainty in the physicochemical and optical properties of volcanic ash particles creates errors in the detection and modeling of volcanic ash clouds and in quantification of their potential impacts in this study we provide a dataset that describes the physicochemical and optical properties of a representative selection of volcanic ash samples from nine different volcanic eruptions covering a wide range of silica contents 50 80 wt sio2 we measured and calculated parameters describing the physical size distribution complex shape and dense rock equivalent mass density chemical bulk and surface composition and optical complex refractive index from ultra violet to near infrared wavelengths properties of the volcanic ash and classified the samples according to their sio2 and total alkali contents into the common igneous rock types basalt to rhyolite we found that the mass density ranges between 2 49 and 2 98 g cm3 for rhyolitic to basaltic ash types and that the particle shape varies with changing particle size d 100 m the complex refractive indices in the wavelength range between 300 nm and 1500 nm depends systematically on the composition of the samples the real part values vary from n 1 38 to 1 66 depending on ash type and wavelength and the imaginary part values from k 0 00027 to 0 00268 we place our results into the context of existing data and thus provide a comprehensive dataset that can be used for future and historic eruptions when only basic information about the magma type producing the ash is known

investigating the use of the saharan dust index as a tool for the detection of volcanic ash in seviri imagery abstract despite the similar spectral signatures of ash and desert dust relatively little has been done to explore the application of dust detection techniques to the problem of volcanic ash detection the saharan dust index sdi is routinely implemented for dust monitoring at some centres and could be utilised for volcanic ash detection with little computational expense thereby providing a product that forecasters already have some familiarity with to complement the suite of existing ash detection tools we illustrate one way in which the index could be implemented for the purpose of ash detection by applying it to three scenes containing volcanic ash from the 2010 eyjafjallajokull eruption iceland and the 2011 eruption of puyehue chile it was also applied to an image acquired over etna in january 2011 where a volcanic plume is clearly visible but is unlikely to contain any ash these examples demonstrate the potential of the sdi as a tool for ash monitoring under different environmental and atmospheric conditions in addition to presenting a valuable qualitative product to aid monitoring this work includes a quantitative assessment of the detection skill using a manually constructed expert ash mask the optimum implementation of any technique is likely to be dependent on both atmospheric conditions and on the properties of the imaged ash which is often unknown in a real time situation here we take advantage of access to a truth rarely available in a real time situation and calculate an ash mask based on the optimum threshold for the specific scene which is then used to demonstrate the potential of the sdi the sdi mask is compared to masks calculated from a simplistic implementation of the more traditional split window method again exploiting our access to the truth to set the most appropriate threshold for each scene and to a probabilistic method that is implemented without reference to the truth and which provides useful insights into the likely cloud ash contamination of each pixel since the sensitivity of the sdi and split window methods to the tailored thresholds was not tested such tailoring is unlikely to be possible in a real situation this study presents the maximum anticipated skill for the sdi in the context of the maximum skill anticipated for the split window method although both are likely to be lower in a real time situation the results for the sdi are comparable to those of the other methods with a true skill score of 80 02 for the eyjafjallajokull night time scene compared to 88 81 and 46 63 for the split window and probabilistic method respectively and 90 06 for the eyjafjallajokull day time scene compared to 97 61 and 56 96 for the puyehue image the sdi resulted in a true skill score of 74 85 while the split window approach achieved 99 62 these results imply that the sdi which is already implemented operationally at some centres for dust detection could be a useful complement to existing ash monitoring techniques

magmatic degassing at erta ale volcano ethiopia abstract here we report measurements of the chemical composition and flux of gas emitted from the central lava lake at erta ale volcano ethiopia made on 15 october 2005 we determined an average so 2 flux of 0 69 0 17 kg s 1 using zenith sky ultraviolet spectroscopy of the plume and molar proportions of magmatic h 2 o co 2 so 2 co hcl and hf gases to be 93 58 3 66 2 47 0 06 0 19 and 0 04 respectively by open path fourier transform infrared ftir spectrometry together these data imply fluxes of 7 3 0 7 0 008 0 03 and 0 004 kg s 1 for h 2 o co 2 co hcl and hf respectively these are the first ftir spectroscopic observations at erta ale and are also some of the very few gas measurements made at the volcano since the early 1970s gerlach t m 1980b investigation of volcanic gas analyses and magma outgassing from erta ale lava lake afar ethiopia journal of volcanology and geothermal research 7 3 4 415 441 we identify significant increases in the proportion of h 2 o in the plume with respect to both co 2 and so 2 across this 30 year interval which we attribute to the depletion of volatiles in magma that sourced effusive eruptions during the early 1970s and or to fractional magma degassing between the two active pit craters located in the summit caldera

variation of structural style and basin evolution in the central zagros izeh zone and dezful embayment iran abstract structural style and its relationship to sedimentary facies and the evolution of sedimentary depocenters since late cretaceous times have been studied on the basis of one regional balanced transect and several updated isopach maps in the izeh zone and the dezful embayment central zagros this study relies on fieldwork data existing geological maps seismic data and well information a new structural classification for part of the zagros sedimentary cover is presented to highlight the different mechanical behavior of the formations in the stratigraphic column it shows the existence of several local decollement levels activated during folding these decollement levels separate lithotectonic units which accommodate shortening in different ways the lower paleozoic is the basal decollement level throughout the studied area triassic evaporites albian shales eocene marls and miocene evaporites can act as intermediate decollement levels and present variable facies in the central zagros lateral facies and thickness variations the sedimentary overburden and the close relationship with inherited fault patterns influenced the wavelength amplitude and style of folding in the study area furthermore surface structures do not necessarily coincide with deeper objectives where these disharmonic levels are involved in folding the evolution of sedimentary depocenters from the late cretaceous obduction episode until early miocene collision is described based on updated isopach maps and tectonic subsidence curves this analysis shows continuous compression and movements along n s and nw se trending faults in the zagros basement which predate the neogene zagros folding and influence sedimentation history it also indicates a southwestward migration of the depocenters through time in addition to the basement involvement below some folds during the zagros orogeny

ftir remote sensing of fractional magma degassing at mount etna sicily abstract the chemical composition of volcanic gas emissions from each of the four summit craters of mount etna was measured remotely in may 2001 using a fourier transform infrared ftir spectrometer operated on the upper flanks of the volcano the results reveal constant hci hf ratio but distinct so2 hc1 and so2 hf ratios in the emitted gases which in the light of melt inclusion data for etna basalts can be interpreted in terms of escape of gases from partially and variably degassed magma at different depths beneath the summit gases released from the three main summit craters bocca nuova voragine and northeast had an identical composition controlled by bulk degassing of a single magma body that had previously lost c 25 0 of its original sulphur the similar gas composition at all three main craters suggests that these are connected to a central conduit system that branches at relatively shallow depth measurements of the bulk volcanic plume on the same day c 7 km downwind show that degassing from these craters dominated the total gas output of the volcano and that no significant chemical evolution occurred within the plume over a time scale of c 12 min weaker gas emissions from the southeast crater were comparatively depleted in so2 so2 hc1 and so2 hf ratios a factor of two lower implying that this crater is fed either by a separate conduit or by a branch of the central conduit whose geometry favours solubility controlled volatile fractionation still lower so2 hc1 and so2 hf ratios measured for residual degassing of a lava flow erupted from the southeast crater verify the lower solubility and earlier escape of sulphur compared to halogens at etna fractional magma degassing is also implied by strong chemical contrasts between the bulk volcanic plume and fissure gas emissions measured during the july august 2001 flank eruption these results highlight the ability of ftir spectrometry to detect fine spatial and temporal variations in magma degassing processes and thereby constrain models of shallow plumbing systems introduction magmas contain dissolved volatiles h20 co2 s c1 f etc with differing solubility behaviom which gradually reach a saturation pressure and exsolve into a separate gas phase bubbles during magma ascent and crystallization this volatile phase plays a central role in magmatic and volcanic processes e g anderson 1975 and its chemical composition changes from depth to the surface according to the pressure controlled solubility behaviour of each volatile species but also as a function of the dynamics of magma supply and ascent sparks 2003 this volume in fact gas bubbles may rise with either the same velocity as surrounding magma allowing continuous gas melt equilibration and single step bulk gas emission at the surface or with a higher velocity thereby reaching the surface independently of the parental magma batch e g sparks 1978 vergniolle jaupart 1986 in the latter case chemical equilibrium between gas and magma may be inhibited sustained high gas fluxes in excess of lava production on basaltic volcanoes such as etna and stromboli typically require a separated bubble flow and in the long term convective renewal of volatile rich magma from depth francis

measurements of the complex refractive index of volcanic ash at 450 546 7 and 650 nm the detection and quantification of volcanic ash is extremely important to the aviation industry civil defense organizations and those in peril from volcanic ashfall to exploit the remote sensing techniques that are used to monitor a volcanic cloud and return information on its properties the effective complex refractive index of the volcanic ash is required this paper presents the complex refractive index determined in the laboratory at 450 0 nm 546 7 nm and 650 0 nm for volcanic ash samples from eruptions of aso japan grimsvotn iceland chaiten chile etna italy eyjafjallajokull iceland tongariro new zealand askja iceland nisyros greece okmok alaska augustine alaska and spurr alaska the becke line method was used to measure the real part of the refractive index with an accuracy of 0 01 the values measured differed between eruptions and were in the range 1 51 1 63 at 450 0 nm 1 50 1 61 at 546 7 nm and 1 50 1 59 at 650 0 nm a novel method is introduced to derive the imaginary part of the refractive index from the attenuation of light by ash the method has a precision in the range 10 3 10 4 the values for the ash imaginary refractive index ranged 0 22 1 70 10 3 at 450 0 nm 0 16 1 93 10 3 at 546 7 nm and 0 15 2 08 10 3 at 650 0 nm the accuracy of becke and attenuation methods was assessed by measuring the complex refractive index of hoya neutral density glass and found to have an accuracy of 0 01 and 2 10 5 for the real and imaginary parts of the refractive index respectively

quantitative shape measurements of distal volcanic ash 1 large scale volcanic eruptions produce fine ash 200 m which has a long atmospheric residence time 1 hour or more and can be transported great distances from the volcanic source thus becoming a hazard to aircraft and public health ash particles have irregular shapes so data on particle shape size and terminal velocities are needed to understand how the irregular shaped particles affect transport processes and radiative transfer measurements in this study a methodology was developed to characterize particle shapes sizes and terminal velocities for three ash samples of different compositions the shape and size of 2500 particles from 1 distal fallout 100 km of the 14 october 1974 fuego eruption basaltic 2 the secondary maxima 250 km of the 18 august 1992 spurr eruption andesitic and 3 the miocene ash hollow member nebraska rhyolitic were measured using image analysis techniques samples were sorted into 10 to 19 terminal velocity groups 0 6 59 0 cm s using an air elutriation device grain size distributions for the samples were measured using laser diffraction aspect ratio feret diameter and perimeter measurements were found to be the most useful descriptors of how particle shape affects terminal velocity these measurement values show particle shape differs greatly from a sphere commonly used in models and algorithms the diameters of ash particles were 10 120 larger than ideal spheres at the same terminal velocity indicating that irregular particle shape greatly increases drag gas adsorption derived surface areas are 1 to 2 orders of magnitude higher than calculated surface areas based on measured dimensions and simple geometry indicating that particle shapes are highly irregular correction factors for surface area were derived from the ash sample measurements so that surface areas calculated by assuming spherical particle shapes can be corrected to reflect more realistic values

the initial giant umbrella cloud of the may 18th 1980 explosive eruption of mount st helens abstract the initial eruption column of may 18th 1980 reached nearly 30 km altitude and released 10 17 joules of thermal energy into the atmosphere in only a few minutes ascent of the cloud resulted in forced intrusion of a giant umbrella shaped cloud between altitudes of 10 and 20 km at radial horizontal velocities initially in excess of 50 m s the mushroom cloud expanded 15 km upwind forming a stagnation point where the radial expansion velocity and wind velocity were equal the cloud was initiated when the pyroclastic blast flow became buoyant the flow reduced its density as it moved away from the volcano by decompression by sedimentation and by mixing with and heating the surrounding air observations indicate that much of the flow covering an area of 600 km 2 became buoyant within 1 5 minutes and abruptly ascended to form the giant cloud calculations are presented for the amount of air that must have been entrained into the flow to make it buoyant assuming an initial temperature of 450 c and a magmatic origin for the explosion these calculations indicate that the flow became buoyant when its temperature was approximately 150 c and the flow consisted of a mixture of 3 25 10 11 kg of pyroclasts and 5 0 10 11 kg of air if sedimentation is considered these figures reduce to 1 1 10 11 kg of pyroclasts and 1 0 10 11 kg of air

basin modelling a new comprehensive method in petroleum geology abstract integrated basin modelling is used to understand and reconstruct the geological and thermal evolution of a sedimentary basin to quantify this information and hence to derive among other results the history of generation migration and accumulation of petroleum this new methodical approach is rapidly gaining world wide recognition throughout the geo scientific community because it offers two distinct advantages when addressing geological problems firstly it enables a logical quantitative treatment of very complex interrelated geological processes and secondly it permits these processes to be examined on the basis of an absolute geological time scale the prerequisites for basin modelling are 1 the translation of logical and consistent geological concepts into numerical form and then into suitable computer programs and 2 the application of these programs using high speed computers with large memories using such an approach is an important part of modern petroleum exploration because 1 1 provision is made for total coverage of the basin by allowing extrapolation to non drilled often deeper parts of the basin accessible only by using seismic data 2 2 a three dimensional view of the basin can be constructed and followed through geological time 3 3 an internal logic is utilised which is consistent with physical and chemical laws 4 4 geological geophysical and geochemical data are integrated and modelled iteratively and therefore control each other this paper shows the rapidly widening scope of basin modelling and points out some of the present day limitations and necessary research directions for the future it describes concepts for modelling of tectonic processes and for simulating expulsion of liquid petroleum

size resolved chemical composition of aerosol emitted by erebus volcano antarctica 1 persistent open vent degassing of erebus volcano antarctica is a significant point source of gases and aerosol to the austral polar troposphere we report here on the chemical composition and size distribution of the erebus aerosol focusing on the water soluble fraction the aerosol was sampled at the rim of the active crater using a cascade impactor which collected and sized particles in 14 size bins from 10 to 0 01 m the soluble fraction of the erebus aerosol is distinct from other volcanic sources in several respects it is dominated by chloride bearing particles over 30 of total mass and has an unusually high cl so42 molar ratio of 3 5 coarse particles contribute little to the total mass of the soluble fraction elevated concentrations of f cl br and so42 are found in a narrow particle size fraction of 0 1 0 25 m the detection of particulate br reinforces our understanding of the potential for quiescent volcanic emissions to deplete tropospheric ozone the small aerosol size reflects the low atmospheric temperature and humidity which inhibit particle growth halide alkali metal salts na k cl f appear to be the most abundant species in the aerosol the concentration of pb is high compared to other volcanoes its exsolution may be promoted by the high abundance of halogens in erebus magma despite the previously reported high nox content in the plume we did not detect significant quantities of nitrate in the near vent aerosol our findings emphasize the potential regional significance of emissions from erebus for understanding the antarctic atmospheric composition and glaciochemical records

environmental effects of ashfall in argentina from the 2008 chaiten volcanic eruption analyses of air water and vegetation samples collected in june 2008 offer new insights into the environmental effects of the may 2008 chaiten eruption on argentina which was subject to significant ashfall between 42 s and 46 s results from air filtration in the ash affected town of esquel with samples analysed by gravimetry and scanning electron microscopy show the total mass of resuspended ash in the air is well correlated with traffic activity however this variation is primarily related to varying amounts of the largest particles with little variation in the amounts of fine ash particles i e d results from water and vegetation sampling with samples analysed by inductively coupled plasma mass spectrometry and ion chromatography indicate that ashfall resulted in significant compositional changes in ephemeral lakes and coiron grass festuca pallescens for b cd zn tl cu and ni there are strong linear correlations between concentrations and ash thickness where 2 mm in both datasets these results suggest that the eruption of chaiten led to significant changes in the concentrations of trace volatile elements within the environment analysis of vegetation samples collected in january 2009 indicates that the elevated element concentrations in coiron grass persisted for 8 months these results offer insights into the environmental fate of volatile trace elements emitted during volcanic eruptions

geochemical characteristics and hydrocarbon generation modeling of the kazhdumi early cretaceous gurpi late cretaceous and pabdeh paleogene formations iranian sector of the persian gulf abstract the marls and argillaceous limestones of the early cretaceous kazhdumi late cretaceous gurpi and paleogene pabdeh formations are considered as potential source rock candidates in this area the present study characterizes hydrocarbon potential type of organic matter and thermal maturity of these three formations in the iranian sector of the persian gulf also 1d basin modeling was used to analyse the burial history and timing of hydrocarbon generation in these formations a total of 179 cutting samples from 25 wells were evaluated through rock eval pyrolysis and organic petrography average total organic carbon toc content for the samples of the kazhdumi gurpi and pabdeh formations that were analyzed for the current study is 1 2 0 9 and 1 wt respectively all three formations show lower toc contents in central part relative to eastern and western parts of the study area rock eval pyrolysis and organic petrography show that the organic matter in all three formations is mainly composed of type ii and mixed type ii iii kerogen this study shows that the kazhdumi gurpi and pabdeh formations in iranian offshore areas are not as rich as onshore areas and specifically in the dezful embayment in terms of organic matter quantity and quality thermal history modeling indicates that constant heat flow values in the range of 64 73 mw m 2 gives the best fit between measured and calculated vitrinite reflectance and bottom hole temperature the rock eval t max vitrinite reflectance and the generated models suggested that in the eastern parts of the study area the kazhdumi formation is at the last stage of oil generation and the gurpi and pabdeh formations are within the main oil generation window hydrocarbon generation began in the early eocene middle eocene and early miocene in the kazhdumi gurpi and pabdeh formations respectively in the western parts of the persian gulf the kazhdumi formation is within the main oil window with hydrocarbon generation took place during the oligocene and the gurpi and pabdeh formations are early mature and immature respectively all three formations are thermally immature in the central part of the persian gulf the kazhdumi formation shows positive correlation with the crude oils of the cretaceous and tertiary reservoirs taken from the northwestern persian gulf the pabdeh and gurpi formations show no correlation with crude oils produced in the northwestern and southeastern persian gulf

eruptive history geochronology and magmatic evolution of the puyehue cordon caulle volcanic complex chile forty three 40 ar 39 ar age determinations of lava flows domes ignimbrites and dikes plus 14 c dates from seven distal tephra layers combined with stratigraphy geochemistry and sr and th isotope data establish an eruptive chronology for the puyehue cordon caulle volcanic complex at 40 5 s in the andean southern volcanic zone svz the complex preserves 131 km 3 of lava and tephra that erupted from numerous vents widely separated in time and space approximately 80 of the total volume consists of basaltic to andesitic lava that formed two broad shield volcanoes between 314 and 70 ka the modern puyehue stratovolcano was built on the southerly shield during the past 69 k y following a hiatus of 25 k y puyehue has erupted 15 km 3 of basaltic to rhyolitic magma that spans the entire compositional range found in the southern svz and evolved via at least six phases including 1 basaltic andesitic to dacitic lavas between 69 and 32 ka 2 a shift to bimodal magma compositions that is first expressed by a rhyodacite mingled with inclusions of mgo rich basaltic andesite at 34 ka 3 dacitic to rhyolitic flows and domes from 19 to 12 ka 4 basaltic to basaltic andesitic flows between 15 and 12 ka 5 subsequent rhyolitic dome growth in several effusive and explosive stages between 7 and 5 ka followed by 6 a powerful series of phreatomagmatic and sub plinian eruptions at ca 1 1 ka that obliterated the preceding rhyolite domes and formed the present 2 5 km diameter 280 m deep summit crater along the cordon caulle fissure zone 5 km 3 of rhyodacitic to rhyolitic lavas domes and cones have formed during the past 16 5 k y including explosive and effusive eruptions in 1921 1922 and 1960 eruptive rates were nonuniform over time with background growth at 0 04 km 3 k y or less punctuated by spurts at up to 0 90 km 3 k y the time averaged rate 0 42 km 3 k y is nearly double that at the tatara san pedro complex 500 km to the north during the past 300 k y these findings indicate that within a single arc the magmatic and eruptive fluxes at individual frontal volcanoes can be highly variable the last three stratocone building events on puyehue began during periods of deglaciation suggesting a relationship between unloading of ice and ease of magma ascent puyehue basalt exhibits subtle changes in 238 u 230 th 87 sr 86 sr and trace element composition over time that signal shifts in the composition and degree of melting of the mantle wedge or the extent to which basalt was modified by assimilation of heterogeneous crustal melts the complex has become exceptionally bimodal and more explosive over time with recent rhyolites evolving by extreme crystal fractionation of mafic magma and lesser volumes of andesite and dacite created via mixing of rhyolite and basalt despite the high flux of basalt during the past 300 k y no large silicic magma reservoir formed in the upper crust instead 238 u 230 th data favor rapid ascent of several small bodies of basaltic and silicic magma from the lower crust promoted perhaps by conduits that reflect strike slip faulting beneath the complex

possible forced folding in the taurus zagros belt of northern iraq the folds in the taurus zagros belt of northern iraq have generally been considered to be decollement buckle folds this implies the presence of a decollement horizon at or near the base of the sedimentary cover the infra cambrian hormuz salt and a passive role of the precambrian basement in the tectonic evolution of the folded belt structural stratigraphic geophysical and remote sensing evidence suggests that forced folding due to faulting in the basement has played a significant role in the development of many of the folds in this region this is clear from the substantial evidence of basement faulting the lack of any convincing evidence for the presence of an extensive and regional decollement horizon i e the hormuz salt between the basement and the cover rocks and the geometries of the folds and related mesostructures the study shows that in the taurus foothills zone the folds are short oval in plan shape and arranged in an en echelon pattern along two sets of dislocation zones in the basement however the folds in the zagros foothills zone are longer linear and arcuate in plan shape many of the studied folds show similar features to those observed in the rocky mountains u s a

burial history and thermal maturity assessment of upper cretaceous lower tertiary formations in the cankiri basin turkey abstract a burial history and thermal maturity investigation has been carried out on upper cretaceous lower tertiary deposits from the cankiri basin this basin which contains post deformational deposits of campanian maastrichtian to pliocene ages forms part of a rich hydrocarbon province defined by the presence of potential hydrocarbon source rocks the stratigraphic sequence was recorded at the cankiri bayat areas and topuzsaray 1 and sagpazar 1 wells at each area the succession was found to be incomplete and important unconformities were present indicating periods of non deposition and or erosion these unconformities are of variable extent a potential source rock interval of upper ypresian and lutetian the yoncali formation which has only the organic rich strata among the other formations in the cankiri basin has been identified it is composed of laminated dark gray shales dominated by type iii kerogen with turbiditic sandstones which were deposited in relatively deep water conditions total organic carbon content values range from 0 5 to 1 0 assessments of time temperature index tti values indicate that the top of the main zone of oil generation is at a depth of 3000 3250 m and the onset of oil generation window for the bayat area took place in the miocene 10 5 my ago and continued into the present coal samples collected from the karabalcik formation of lutetian age are high in ash and sulfur petrographic identifications on the polished blocks in reflected light indicate that the coal samples include abundant huminite vitrinite group macerals mean random huminite vitrinite reflectance values of the coal samples are between 0 51 and 0 53 rrandom oil av 0 52 rr oil indicating low rank coals subbituminous a high volatile c bituminous according to the astm classification

comprehensive source rock evaluation of the kazhdumi formation in the iranian zagros foldbelt and adjacent offshore abstract the kazhdumi formation is regarded as one of the most prolific hydrocarbon sources in the zagros foldbelt and adjacent offshore rock eval pyrolysis data were collected from 2300 rock samples of the kazhdumi formation in 64 wells core and cutting including 37 oil and gas fields and five outcrops 200 vitrinite reflectance measurements were carried out to calibrate and map thermal maturity over the study area palynofacies analyses and thermal history modeling were applied on the wells located in the study area based on the total organic carbon toc map the kazhdumi formation toc values range from 0 to 11 in the central part of dezful embayment its average value is about 5 while average toc value of the kazhdumi formation is lower than 0 5 in qatar gawbandi paleo high hydrogen index hi values represented types ii and iii kerogen for central part of the dezful embayment and qatar gawbandi paleo high respectively t max ranges from 370 to 455 c in the study area the maximum and minimum values for this parameter are recorded in the central dezful embayment and central persian gulf anticlines respectively vitrinite reflectance vr r map also confirms the concluded results of t max data reconstructed burial history and thermal modeling of three wells are also in full agreement with the results of other maturity evidence t max and vr r palynofacies analyses revealed that this formation in the central persian gulf south pars field clearly represents the dominance of terrigenous elements which were resulted from a close proximity to a fluvio deltaic source however towards the northwest amorphous organic matter aom dominates in central dezful embayment indicating a distal dysoxic anoxic environmental condition

optical properties of the ash from el chichon volcano we have measured visible wavelength optical properties of the ash from the 1982 el chichon eruptions these measurements were made on ash samples collected at three surface sites at distances between 12 and 80 km from the volcano the most distant sample is taken as most representative of the silicate ash injected into the stratosphere the measured optical properties are expressed as a complex refractive index n with the aerosol absorption expressed as the imaginary component of the refractive index nim each of these samples showed quite low values of absorption with nim at 500 nm ranging from 1 5 10 3 for the 12 km sample to 1 0 10 3 for the 80 km sample based on these measurements we estimate that n for the stratospheric silicate ash is given by n 1 53 0 001i

reconstructing eruptive source parameters from tephra deposit a numerical study of medium sized explosive eruptions at etna volcano since the 1970s multiple reconstruction techniques have been proposed and are currently used to extrapolate and quantify eruptive parameters from sampled tephra fall deposit datasets atmospheric transport and deposition processes strongly control the spatial distribution of tephra deposit therefore a large uncertainty affects mass derived estimations especially for fall layer that are not well exposed this paper has two main aims the first is to analyse the sensitivity to the deposit sampling strategy of reconstruction techniques the second is to assess whether there are differences between the modelled values for emitted mass and grainsize versus values estimated from the deposits we find significant differences and propose a new correction strategy a numerical approach is demonstrated by simulating with a dispersal code a mild explosive event occurring at mt etna on 24 november 2006 eruptive parameters are reconstructed by an inversion information collected after the eruption a full synthetic deposit is created by integrating the deposited mass computed by the model over the computational domain i e an area of 7 5 104 km 2 a statistical analysis based on 2000 sampling tests of 50 sampling points shows a large variability up to 50 for all the reconstruction techniques moreover for some test examples power law errors are larger than estimated uncertainty a similar analysis on simulated grain size classes shows how spatial sampling limitations strongly reduce the utility of available information on the total grain size distribution for example information on particles coarser than 4 is completely lost when sampling at 1 5 km from the vent for all columns with heights less than 2000 m above the vent to correct for this effect an optimal sampling strategy and a new reconstruction method are presented a sensitivity study shows that our method can be extended to a wide range of eruptive scenarios including those in which aggregation processes are important the new correction method allows an estimate of the deficiency for each simulated class in calculated mass deposited providing reliable estimation of uncertainties in the reconstructed total whole deposit grainsize distribution

geochemistry of upper miocene lower pliocene source rocks in the hellenic fold and thrust belt zakynthos island ionian sea western greece abstract the southwestern margin of the hellenic fold and thrust belt situated along the southern edge of the dinarides albanides hellenides continental convergent zone has been studied in terms of its hydrocarbon generating potential the upper miocene lower pliocene tortonian to zanclean clastic sedimentary succession at zakynthos island provides an excellent opportunity to evaluate the source rock potential of such a system twenty seven mudstone samples were analyzed using organic geochemical techniques such as rock eval pyrolysis bitumen extraction open column chromatography and gas chromatography mass spectrometry the obtained data indicate that the sedimentary sequence contains units with sufficient organic material of good enough quality to be considered as potential source rocks the input of terrestrial organic material and associated gaseous generating potential is indicated by 1 rock eval pyrolytic yields and calculated values of hydrogen and oxygen indices 2 n alkane distribution with dominant long chain components 3 high terrigenous to aquatic organic material ratios 4 odd to even predominance values 5 low sulfur content and 6 occurrence of gammacerane the kerogen is immature as evidenced by 1 t max and production index values 2 odd to even predominance values 3 low diasterane to sterane and pr ph ratios 4 low 20s 20s 20r and sterane ratios and 5 presence of gammacerane

organic geochemistry and petrography of kazhdumi albian cenomanian and pabdeh paleogene potential source rocks in southern part of the dezful embayment iran there are several source rock units in the zagros basin but the cretaceous kazhdumi and paleogene pabdeh formations probably have produced the majority of the commercial hydrocarbons in this area among the hydrocarbon provinces of iran the dezful embayment which is located southwest of zagros mountains is one of the most prolific regions in the middle east numerous studies have been made in the northern part of the dezful embayment but relatively few have been done in its southern part the present study focuses on organic matter characterization of two potential source rocks kazhdumi and pabdeh formations in southern part of the dezful embayment cuttings samples 114 were collected from 10 wells and evaluated using rock eval pyrolysis and organic petrography in order to characterize the content and type of organic matter and thermal maturity the results showed that the average total organic carbon toc content of kazhdumi and pabdeh formations are 2 48 and 1 62 wt respectively the highest toc contents for both formations are found in the northern compartment and decreased gradually toward the south pyrolysis data reveal that organic matter has a fair to very good hydrocarbon generation potential and are classified as type ii iii and type iii rock eval t max and vitrinite reflectance show that the majority of samples are in the early mature to mature stage of the oil generation window c 2012 elsevier ltd all rights reserved

so2 as a possible proxy for volcanic ash in aviation hazard avoidance 1 airborne volcanic ash poses a significant danger to aircraft but is difficult to quantify accurately using satellite data while sulphur dioxide is much easier to detect accurately but is much less of a direct hazard to aviation this paper investigates the reliability of using so2 as a proxy for the location of volcanic ash using an so2 retrieval from the infrared atmospheric sounding interferometer iasi and ash detections from iasi and the advanced along track scanning radiometer aatsr using a numerical missed ash fraction applied to the eruptions of eyjafjallajokull in 2010 and puyehue cordon caulle in 2011 reveals that the so2 flag typically misses 30 of the detectable ash furthermore the missed ash fraction is found to be highly variable both between the two eruptions and over the course of each eruption with values of over 80 found on some days the detection threshold of the aatsr ash flag is also investigated using radiative transfer calculations allowing the threshold of the iasi flag to be inferred and these are related to the ash contamination levels

simultaneous retrieval of volcanic ash and so2 using msg seviri measurements 1 volcanic ash and sulphur dioxide masses from the november 2005 eruption of karthala volcano comoros islands are simultaneously retrieved using rapid scan multispectral infrared measurements from the spin enhanced visible and infrared imager on board the meteosat second generation geosynchronous satellite retrievals are made every 15 min which show that the ash and so2 separate in the vertically sheared atmosphere producing a fast moving upper level 12 km so2 cloud a slower moving middle level 8 km ash cloud and a boundary layer 3 km so2 plume the total mass of fine ash is 0 1 0 05 tg sio2 the upper level so2 mass is 0 19 0 01 tg s while the boundary layer so2 mass is 0 009 0 01 tg s these are the first simultaneous satellite measurements of ash and so2 from an erupting volcano and confirm previous ideas about vertical separation we suggest care must be exercised when using so2 as a tracer for volcanic ash in aviation hazard warning systems

organic geochemistry of crude oils and cretaceous source rocks in the iranian sector of the persian gulf an oil oil and oil source rock correlation study abstract the marls and argillaceous limestones of the cretaceous kazhdumi formation ahmadi member of the sarvak formation and gurpi formation are considered to be important source rock candidates in the persian gulf to evaluate their source rock characteristics 265 cutting samples of these rock units from 20 fields in offshore iran were analyzed using rock eval pyrolysis organic petrography stable carbon isotope composition and biomarker analysis 1d basin modeling was also applied to analyze the burial and thermal history of these source rock candidates based on the results the kazhdumi and gurpi formations which have fair source rock potential and the ahmadi member which has fair to good source rock characteristics were deposited in a marine reducing environment with marine organic matter as the main input different maturity indicators showed that the ahmadi member and kazhdumi formation are thermally immature to mature and the gurpi formation is immature to early mature in the study area the results of the modeling suggested that the kazhdumi formation and ahmadi member in the southeastern parts of the study area are within the main oil window and that the gurpi formation has just begun to generate hydrocarbons all three formations are thermally immature in the eastern parts in the western parts of the persian gulf the kazhdumi formation is early mature and the other formations are immature the biomarker and stable carbon isotope parameters of these rock units were compared with 20 crude oil samples in the southeastern persian gulf based on the hierarchical cluster analysis hca principal component analysis pca and carbon isotope composition the studied crude oils were divided into two groups group i oils from cretaceous reservoirs were probably derived from cretaceous source rocks while group ii oils from jurassic and cretaceous reservoirs with jurassic rocks as the expected source rocks the performed oil source rock correlation shows a positive correlation between the group i oils and the ahmadi member

remote sensing of active volcanoes the synoptic coverage offered by satellites provides unparalleled opportunities for monitoring active volcanoes and opens new avenues of scientific inquiry thermal infrared radiation can be used to monitor levels of activity which is useful for automated eruption detection and for studying the emplacement of lava flows satellite radars can observe volcanoes through clouds or at night and provide high resolution topographic data in favorable conditions radar inteferometery can be used to measure ground deformation associated with eruptive activity on a centimetric scale clouds from explosive eruptions present a pressing hazard to aviation therefore techniques are being developed to assess eruption cloud height and to discriminate between ash and meterological clouds the multitude of sensors to be launched on future generations of space platforms promises to greatly enhance volcanological studies but a satellite dedicated to volcanology is needed to meet requirements of aviation safety and volca

intrusion triggering of the 2010 eyjafjallajokull explosive eruption the ash cloud that brought chaos to european air traffic in april this year was the result of emissions from an icelandic volcano that had been intermittently active for about 18 years a combination of detailed space based geodetic measurements and seismic monitoring of the eyjafjallajkull volcano in the run up to the ash producing explosive summit eruption reveals an unusual deformation pattern that may be attributed to its off rift setting with relatively cool subsurface structure and limited magma at shallow depth as to the predictability of such a dramatic reawakening the immediate precursors to the initial eruption of the volcano in 2010 were subtle and difficult to detect but the clear signs of volcanic unrest during the weeks months and years preceding it may provide better clues to the catastrophic explosion

remote sensing of volcanoes and volcanic processes integrating observation and modelling introduction volcanoes are often remote and have footprints that may extend across many hundreds or thousands of square kilometres they are generally inaccessible during eruption and may continue to be inaccessible for extended periods of time after eruption while their products can be scattered or dispersed over regional or global scales consequently since direct measurement can only provide us with part of the picture of many volcanic processes remote sensing is now playing an increasingly important role in advancing understanding of the science underlying volcanic behaviour on this planet and beyond e g mouginis mark et al 2000 sparks et al 2012 satellite airborne and ground based remote sensing are increasingly vital tools for monitoring active or potentially active volcanoes and assessing their likely real time or time averaged impact fig 1 at the same time the synoptic scale surveys that are often well suited to remote sensing techniques allow us to address questions about the fundamental processes that control volcano behaviour in a way that is not necessarily possible from individual case studies new research is often driven by technological advancements in the development of novel sensors or launching of new platforms meaning that the space agencies are increasingly involved in identifying scientific questions and priorities e g ferruci et al 2012 multiple and complementary data streams are increasingly being used both to monitor active volcanoes and advance volcanological science the key geophysical parameters that comprise monitoring data streams typically include the categories of i seismicity ii surface deformation iii thermal measurements and iv gas flux and composition data as major components while measurements of seismicity remain the domain of ground based seismometers remote sensing techniques have made major contributions in each of the others this special publication volume is concerned with the use of remote sensing at volcanoes it is split into three parts roughly arranged from the subsurface to the surface and then further afield as volcanic products are injected and dispersed into the atmosphere the papers span a range of applications of remote sensing techniques to monitor and understand a surface deformation b surface thermal anomalies and c gas fluxes as well as tracking ash and gas plumes from eruptions to gain insights into the extent of a volcano s impacts volcanology is driven in part by the operational concerns surrounding volcano monitoring and hazard and crisis management but the goal of volcanological science is at its heart to understand the processes that underlie volcanic activity this special publication is also concerned with how we go from observations to this deeper understanding including the progress that can be made by integrating observations and modelling while this volume focuses mainly on satellite based remote sensing integrating datasets from different platforms is also of vital importance and so papers on airborne remote sensing and measurement from both manned and unmanned aircraft are also included

petroleum system analysis of the northwestern part of the persian gulf iranian sector abstract geochemical geological and geophysical data were used to identify and update genetic oil families potential source rocks and hydrocarbon generation kitchen as well as probable migration pathways in the northwestern part of the persian gulf rock eval analysis was performed on 52 cutting samples of prospective cretaceous tertiary source rocks according to the results most of the samples have poor to fair potential for hydrocarbon generation except for the albian formation which possesses good to excellent source rock characteristics in the study area two genetic oil families were identified based on source and age related biomarkers as well as stable carbon isotope ratios for 23 crude oil samples family i occurs in upper jurassic lower cretaceous reservoirs mainly in the surmeh hith basin whereas family ii occurs in lower cretaceous tertiary reservoirs mainly in the garau gotnia basin all attempts to correlate the identified families to prospective source rocks failed due to substantial maturity differences between the oils and rock samples inversion correlation based on detailed isotopic and biomarker analyses however confirms that the carbonates and marls of the neocomian and albian formations are the main oil generating facies for families i and ii respectively the geographical extension and composition of the identified oil families are highly affected by source rock facies distribution and migration pathways 2d cross sections provided in the region indicate the dominance of lateral and vertical migration pathways from the binak depression as the main hydrocarbon generation kitchen toward the structural highs in the study area

automated high time resolution measurements of so2 flux at soufriere hills volcano montserrat we report here the first results from an automated telemetered uv scanning spectrometer system for monitoring so2 emission rates at soufriere hills volcano montserrat two spectrometers receive light by way of a motor driven stepping prism and telescope in order to make vertical scans of the volcanic plume spectral data from these spectrometers situated 2 800 m apart and 4 500 m from the volcano are relayed back to the observatory every 4 5 s via radio modems a full scan of the plume is accomplished every 1 6 min by the time synchronised spectrometers and a so2 emission rate is calculated using the so2 slant concentrations scan angles and plume speeds estimated from the wind speed from a telemetered weather station near to the volcano the plume s position and dimensions are calculated using the angular data from the two spectrometers the plume height varies significantly diurnally and seasonally and is important in order to minimise the error on so2 emission rates the new scanning system scanspec provides so2 emission rates from 08 00 to 16 00 h local time every day preliminary results highlight a number of features of the so2 time series and plume dynamics and give our first indications of the errors and limits of detection of this system so2 emission rates vary widely on all time scales minutes days months this new system has already provided the first real and consistent indication that so2 emission rates vary on a minutes to hours basis which can be correlated with volcanic activity for example rockfall and pyroclastic flow activity it is anticipated that this system at soufriere hills will yield information on shallow processes occurring on short time scales periods of minutes to hours as well as deep processes relating to magma supply rates which will be associated with longer wavelength so2 signals of weeks to months

progressive unconformities within an evolving foreland fold thrust belt zagros mountains a major angular unconformity between the bakhtyari conglomerates and the underlying agha jari formation has long been interpreted as indicating that orogeny in the zagros simply folded zone took place in plio pleistocene times this study uses field evidence of unconformities between older units in conjunction with geological maps and cross sections to argue that the front of the zagros simply folded zone has propagated in time and space these unconformities indicate that deformation started as early as end eocene in the northeast of the simply folded zone and propagated progressively to the southwest where unconformable contacts are only seen between younger units as shortening continued the southwest migration of the deformation front drove the foreland basin in front of it to its present position along the persian gulf and mesopotamia the climax of orogeny took place at end pliocene time when the most extensive unconformity in the zagros simply folded zone developed between the upper bakhtyari formation and older units active seismicity and documented present uplift imply that the simply folded zone is still propagating southwestward

detachment folding in the central and eastern zagros fold belt iran salt mobility multiple detachments and late basement control abstract detachment folding has been studied on the basis of field and subsurface examples from the central and eastern zagros iran we discuss different aspects of detachment folding well illustrated in the studied area in particular we focus on salt mobility multiple decollements and late basement control salt mobility concerns the hormuz basal detachment and the gachsaran upper detachment for the latter it is shown that mobility results not only from folding related diapirism but also from early gravity driven migration from growing anticlines towards intervening synclines concentric folding between two detachment levels is directly observed in the izeh zone central zagros where it is shown that the wave length depends on the distance between the two active decollements and that the fold shape is a function of the level of erosion throughout the zagros detachment folds mainly developed during an initial thin skinned phase of deformation which was followed by the current thick skinned stage this succession is particularly well expressed in the eastern zagros where basement faults cut early detachment folds obliquely

thermal monitoring of lascar volcano chile using infrared data from the along track scanning radiometer a 1992 1995 time series lascar volcano 22 22 s 67 44 w is the most active volcano of the central andes of northern chile activity since 1984 has been characterised by periods of lava dome growth and decay within the active crater punctuated by explosive eruptions we present herein a technique for monitoring the high temperature activity within the active crater using frequent measurements of emitted shortwave infrared swir radiation made by the spaceborne along track scanning radiometer atsr the atsr is an instrument of low spatial resolution pixels 1 km across that shares certain characteristics with the modis instrument planned for use as a volcano monitoring tool in the nasa eos volcanology project we present a comprehensive time series of over 60 cloud and plume free nighttime atsr observations for 1992 1995 a period during which lascar experienced its largest historical eruption variations in short wavelength infrared flux relate directly to changes in high temperature surfaces within the active crater from these data interpretations can be made that supplement published field reports and that can document the presence and status of the lava dome during periods where direct ground based observations are lacking our data agree with less frequent information collected from sensors with high spatial resolution such as the landsat thematic mapper oppenheimer et al 1993 and are consistent with field observations and models that relate subsidence of the dome to subsequent explosive eruptions matthews et al 1997 most obviously lascar s major april 1993 eruption follows a period in which the magnitude of emitted shortwave infrared radiation fell by 90 at this time subsidence of the 1991 1992 lava dome was reported by field observers and this subsidence is believed to have impeded the escape of hot volatiles and ultimately triggered the eruption smithsonian institution 1993a extrapolating beyond the period for which field observations of the summit are available our data show that the vulcanian eruption of 20 july 1995 occurred after a period of gradual increase in short wavelength infrared flux throughout 1994 and a more rapid flux decline during 1995 we attribute this additional otherwise undocumented cycle of increasing and decreasing swir radiance as most likely representing variations in degassing through fumaroles contained within the summit crater alternatively it may reflect a cycle of dome growth and decay the explosive eruption of 17 december 1993 appears to have followed a similar but shorter variation in swir flux and we conclude that large explosive eruptions are more likely when the 1 6 m signal has fallen from a high to a low level the atsr instrument offers low cost data at high temporal resolution despite the low spatial detail of the measurements atsr type instruments can provide data that relate directly to the status of lascar s lava dome and other high temperature surfaces we suggest that such data can therefore assist with predictions of eruptive behaviour deduced from application of physical models of lava dome development at this and similar volcanoes

burial history reconstruction and thermal maturity modeling for the middle cretaceous early miocene petroleum system southern dezful embayment sw iran abstract the middle cretaceous early miocene petroleum system is the most important hydrocarbon system in the zagros basin rock eval pyrolysis organic petrography and thermal 1d modeling were performed on wells located in the southern dezful embayment the results provide information on organic matter quantity and quality as well as burial and thermal histories of source rocks in the framework of the basin evolution a total of 98 cutting samples from bk 4 kk 1 si 4 and rs 2 wells were pyrolyzed by rock eval 6 also thermal maturity of organic matter derived from tmax of rock eval was interpreted in conjunction with vitrinite reflectance data 50 samples the toc values of the sequences mainly range from 0 5 to 2 5 wt the average values of tmax and vitrinite reflectance indicate that samples from the wells have reached maturities corresponding to early mid oil generation reconstruction of thermal history suggests that various steady heat flow values 62 54 50 and 56 mw m2 for bk 4 kk 1 si 4 and rs 2 wells respectively resulted in the best fit between the calculated and the observed vitrinite reflectance and bottom hole temperatures in our modeling thus values of heat flow decrease from 60 mw m2 in the southern basin margin to about 50 mw m2 along the ne of the dezful embayment and the zagros basin according to our modeling results the onset of oil generation from source rocks in the studied area occurs well after deposition of the seal rock and formation of traps ensuring entrapment and preservation of migrated hydrocarbons

petroleum source rock potential of the piranj oil field zagros basin abstract zagros basin constitutes one of the most prolific hydrocarbon producing habitats and the second largest basin in the middle east the piranj oil field is part of the middle cretaceous early miocene petroleum system in zagros basin and southwest of iran this study mainly focuses on organic matter characterization and thermal history of two potential source rock s name gurpi and pabdeh formations to evaluate the candidate source rocks 50 cuttings and core samples of these rock units from well m 11 the only well drilled up to the probable source rocks were analysed using rock eval pyrolysis and organic petrography in addition 1d basin modelling and reconstruction of burial history were applied to analyse the thermal history of these source rocks the green shale limestone and marls of pabdeh formation with average 2 52 wt total organic matter toc and hydrogen index hi higher than 250 is more favourite source rock in comparison with dark shale and limestone of gurpi formation by 1 8 wt and hi r from 0 44 to 1 23 indicate that samples from the well m 11 have reached maturities corresponding to early to peak oil generation reconstruction of the thermal history suggests various steady heat flow values 53 91 mw m 2 resulted in the best fit between the observed and the calculated bottom hole temperatures bht and vitrinite reflectance v r in the model rock eval pyrolysis results and vitrinite reflectance v r suggest that the most of samples are in the early mature to mature stage of hydrocarbon generation furthermore according to the modelling results petroleum generation from the studied source rocks has began after deposition of related seal rocks and formation of traps which ensures entrapment and preservation of migrated hydrocarbon

the respiratory health hazards of volcanic ash a review for volcanic risk mitigation studies of the respiratory health effects of different types of volcanic ash have been undertaken only in the last 40 years and mostly since the eruption of mt st helens in 1980 this review of all published clinical epidemiological and toxicological studies and other work known to the authors up to and including 2005 highlights the sparseness of studies on acute health effects after eruptions and the complexity of evaluating the long term health risk silicosis non specific pneumoconiosis and chronic obstructive pulmonary disease in populations from prolonged exposure to ash due to persistent eruptive activity the acute and chronic health effects of volcanic ash depend upon particle size particularly the proportion of respirable sized material mineralogical composition including the crystalline silica content and the physico chemical properties of the surfaces of the ash particles all of which vary between volcanoes and even eruptions of the same volcano but adequate information on these key characteristics is not reported for most eruptions the incidence of acute respiratory symptoms e g asthma bronchitis varies greatly after ashfalls from very few if any reported cases to population outbreaks of asthma the studies are inadequate for excluding increases in acute respiratory mortality after eruptions individuals with pre existing lung disease including asthma can be at increased risk of their symptoms being exacerbated after falls of fine ash a comprehensive risk assessment including toxicological studies to determine the long term risk of silicosis from chronic exposure to volcanic ash has been undertaken only in the eruptions of mt st helens 1980 usa and soufriere hills montserrat 1995 onwards in the soufriere hills eruption a long term silicosis hazard has been identified and sufficient exposure and toxicological information obtained to make a probabilistic risk assessment for the development of silicosis in outdoor workers and the general population a more systematic approach to multi disciplinary studies in future eruptions is recommended including establishing an archive of ash samples and a website containing health advice for the public together with scientific and medical study guidelines for volcanologists and health care workers

fracture controlled magma conduits in an obliquely convergent continental magmatic arc magnetic fabric patterns of two mid cretaceous nested plutons 102 1 and 96 3 ma in the central sierra nevada batholith provide evidence that felsic magma emplacement and ascent occurred via north trending steeply dipping planar fracture conduits oriented obliquely to the arc u pb geochronology data indicate that emplacement of the plutons was separated by 2 to 10 m y and that they were emplaced in part via the same conduit magnetic fabrics in the younger pluton are related to its final emplacement which was strongly influenced by a system of host rock joints formation of the north trending conduits at 100 ma can be related to a small arc parallel dextral shear component that produced tension fractures and that was associated with high angle oblique convergence by 90 ma convergence had become sufficiently oblique for the development of nearly arc parallel structures which were then favored as magma conduits

study of hydrocarbon generation and 1d 2d modeling of hydrocarbon migration at the karanj and parsi oilfields southern dezful embayment sw iran abstract this study is a 2d basin modeling to determine the petroleum system i e cretaceous neogene play of the karanj and parsi oilfields in the southern dezful embayment sw iran this system is characterized by occurrence of source rocks of middle cretaceous late cretaceous and paleocene to eocene kazhdumi pabdeh and gurpi formation reservoirs of upper cretaceous and late oligocene early miocene ilam sarvak and asmari formations and seals of paleocene and miocene pabdeh and gachsaran formation considering temperature transformation ratio and vitrinite reflectance the maturity of source rocks kazhdumi pabdeh and gurpi formation was investigated a maturity history analysis showed that the maturity of kazhdumi pabdeh and gurpi formation started during 70 60 and 4 ma respectively generation and expulsion of hydrocarbons started 16 ma in the kazhdumi formation and 3 ma in the pabdeh formation that continued up to the present the analysis of the transformation ratio indicates transformation of significant amounts of kazhdumi source rocks for generating hydrocarbons migration of hydrocarbons from the kazhdumi formation is mainly vertically upward from pabdeh formation migration is both vertically upward to the asmari reservoir and downwards to the ilam sarvak reservoir however some local traps have formed due to the hydrocarbon accumulation above the faults our results reveal that petroleum generation migration and entrapment occurred at proper timing which facilitated the migration of hydrocarbons and their accumulation in the reservoirs

geological history and petroleum system of the mittelplate oil field northern germany the geological history of germany s largest and most productive petroleum accumulation the mittelplate oil field in schleswig holstein northern germany is reconstructed by simulating the structural and thermal evolution along a 2d cross section the mittelplate field is located at the western flank of the busum salt dome at the transition from the schleswig holstein mainland to the german north sea sector organic geochemical data confirm the lower jurassic posidonia shale to be the predominant oil source rock in the schleswig holstein area the studied section is characterized by salt walls and salt domes built up by permian evaporites reconstruction of the structural and thermal evolution of the mittelplate field by means of basin modelling reveals the dominating influence of salt dynamics on the entire petroleum system the development of secondary rim synclines during salt rise provided accommodation space for the deposition of the posidonia shale as well as the deltaic middle jurassic reservoir sandstones the rise of the nearby oldenswort salt wall controlled the timing of maturation and petroleum generation during cenozoic times hydrocarbon migration from the posidonia shale into the reservoirs occurred up dip from the deeper subsiding rim syncline into the structural trap with the middle jurassic reservoir sandstones pinching out at the flank of the busum salt dome along the modelled 2d section the field s recent temperature field and its complex reservoir architecture are reconstructed