geology and tectonics of the betic zone se spain abstract the southern margin of the iberian continent comprises a complex geological history which can be traced back into the proterozoic when a gneissic basement was formed a cover of nevado filabride rocks was deposited onto this proterozoic basement during the palaeozoic the permian intrusion of the bedar granite suggests that the palaeozoic sedimentary rocks now exposed in the betic cordilleras have been affected by the hercynian orogeny similar to that of palaeozoic rocks in the adjoining ossa morena zone the hercynian basement was probably covered by alpujarride carbonates in the mesozoic when rifting opened tethys and intruded 140 ma old basic dyke swarms the palaeozoic basement of the betic cordilleras comprises a suture of late cretaceous subduction 80 85 ma b p this can be inferred from hp lt metamorphic facies obducted in coeval thrust slices of nevado filabride rocks the nevado filabride nappes include mesozoic carbonates transformed into marbles macael the suture was probably annnealed after the closure of tethys the mesozoic boundary between africa and europe and the rifting in tethys ceased during the palaeogene when the atlas mountains were formed 36 ma b p subsequently relative movements between africa and europe in the neogene were accommodated by strike slip faults these define the iberian microplate moving eastward by atlantic spreading and possibly subducting under italy neogene deformation of iberia is most intensive in southeastern spain due to emplacement of a mantle diapir under the alboran area this occurred early in the neogene aquitanian and caused nappe spreading involving alpujarride and malaguide rocks the subsequent neogene history has now been studied in great detail and is reviewed here it involves clear examples of calc alkaline volcanism most probably not related to subduction seismic motion along strike slip faults within the iberian microplate and syntectonic deposition in intermontane neogene basins

estimation of rock physics properties from seismic attributes part 2 applications abstractthe estimation of quantitative rock physics properties is of great importance for reservoir characterization and monitoring in co2 storage or enhanced oil recovery as an example we have combined the high resolution results of full waveform inversion fwi methods with rock physics inversion because we consider a generic and dynamic rock physics model our method is applicable to most kinds of rocks for a wide range of frequencies the first step allows determination of viscoelastic effective properties i e quantitative seismic attributes whereas the rock physics inversion estimates rock physics properties porosity solid frame moduli fluid phase properties or saturation this two step workflow is applied to time lapse synthetic and field cases the sensitivity tests that we had previously carried out showed that it can be crucial to use multiparameter inputs to accurately recover fluid saturations and fluid properties however due to the limited data availability and difficulties in get

late oligocene miocene syn late orogenic successions in western and central mediterranean chains from the betic cordillera to the southern apennines the identification of syn and late orogenic flysch deposits extending from the betic cordillera to the southern apennines assists in the reconstruction of the tectonic sedimentary evolution of the perimediterranean chains a microplate was located between the european and african plates during the late jurassic early cretaceous bordered northwards by the piemontese ocean and southwards by another north africa flysch basin or maghrebian ocean the piemontese ocean and the northern margin of the microplate were structured from the late cretaceous to the eocene to create an eo alpine chain the southern margin of the microplate was deformed in the aquitanian when the internal areas of the maghrebian ocean were characterized by syn orogenic flysch deposits this episode culminated with metamorphism 25 22 ma and nappe emplacement which destroyed the former palaeogeography and created an orogenic belt alkapeca afterwards a lower burdigalian late orogenic cycle started in the deformed area which as a result of the opening of the algero provencal basin caused the fragmentation of the alkapeca its thrusting on the flysch basin and the collision with the north africa and south iberia margins these latter were folded and thrusted the flysch units pushed over the external domain and also back thrusted langhian late orogenic deposits suture the new tectonic features finally the whole orogen was thrust onto the foredeep during the middle late miocene

mixing processes in modern estuarine sediments from the gulf of khambhat western india abstract sandy and muddy detritus from two distinctive end member provenance terrains basaltic and granitic are transported to the estuaries of the gulf of khambhat by fluvial discharge and opposing tidal currents making this embayment ideal for investigating the effects of mineralogical and geochemical mixing on sediment composition in estuarine depositional systems rivers flowing predominantly from the north over precambrian metasediments and granites supply a felsic plutoniclastic sand to the gulf whilst a mafic volcaniclastic sand sourced by deccan basalts is transported by rivers draining the western ghats and from the local coastal erosion in the southern part of the gulf sediments from the tapti estuary are rich in basaltic rock fragments 50 and are characterised by a distinctly basaltic source composition la sc 0 25 0 86 th sc 0 12 0 40 cr th 13 121 eu eu 0 93 1 68 and lree hree 2 96 6 57 by contrast the sediments of the sabarmati inner estuary are rich in quartz grains 80 as evident from the major and trace element compositions la sc 1 38 6 63 th sc 0 58 2 98 cr th 0 58 19 39 eu eu 0 46 0 86 and lree hree 2 90 11 40 the detrital compositions of the remaining major estuaries the narmada dhadhar and mahi scatter across a broad range in a qfr diagram and contain varying amounts of quartz feldspar and rock fragments in the narmada estuary the mixed signature characterised by ree values including eu eu 0 42 2 28 and lree hree 4 37 14 80 is caused by the presence of diverse rock types that crop out in the source area in the mahi estuary which largely flows across felsic source terrains the compositional signature is controlled by mixing of felsic detritus from riverine input with mafic sediments from seaward side in the estuary the two end member detrital compositions plutoniclastic and volcaniclastic are mixed in the macro tidal estuaries mixing of sediment takes place where fluvial currents and tidal flows interact and the proportion of mixing varies systematically from outer to central to inner estuary a high degree of mixing of felsic sediments with deccan basalt derived sediments takes place in the outer estuary resulting in felsic mafic ratios of 40 60 sediments in the central estuaries 65 35 and in the fluvial dominated inner estuaries 90 10 are characterised by moderate to minor degrees of mixing the mixing in estuaries is systematic and is reflected in both the mineralogy and geochemistry of the sediments provenances of ancient estuarine successions should therefore be interpreted with great care incorporating awareness of the mixing processes which influence sediment compositions to different degrees in estuaries especially those characterised by strong tidal currents

application of actualistic sand petrofacies in hydrogeology an example from the northern sacramento valley california usa diverse detrital source areas surrounding the sacramento valley of northern california and the abundance of deep water wells from which sand samples can be acquired make this an ideal natural laboratory in which to apply actualistic sand petrofacies methods in solving hydrogeologic subsurface problems discriminant analysis identifies four distinct compositional suites petrofacies representing four distinct sources metamorphic m volcanic v mixed volcanic and metamorphic vm and mixed volcanic metamorphic and sedimentary vms proportions of aphanitic metamorphic volcanic and sedimentary lithic fragments using the gazzi dickinson point counting method are the primary distinguishing parameters the combined surface and subsurface mapping of lithofacies and petrofacies confirms that the tehama and tuscan formations interfinger in the subsurface near the center of the northern sacramento valley the pliocene pleistocene tehama formation along the west side predominantly consists of metamorphiclastic detritus derived from the klamath mountains and the coast ranges including the franciscan complex and the great valley group the pliocene pleistocene tuscan formation along the east side predominantly consists of volcaniclastic detritus derived from the southern end of the cascade range and the modoc plateau these petrofacies results complement regionally integrated surface mapping and subsurface data in order to construct regional cross sections showing basin architecture the general correspondence between lithofacies and petrofacies provides a powerful tool for further investigation but the lack of correspondence in a few cases indicates where additional work is warranted the simultaneous study of sand composition and three dimensional geologic relations provides additional insights regarding the architecture of aquifers knowledge of which improves water resource development and management

the recycled orogenic sand provenance from an uplifted thrust belt betic cordillera southern spain the betic cordillera of southern spain represents an uplifted foreland fold thrust belt source rock types of the betic cordillera include metamorphic mainly phyllite schist quartzite and gneiss sedimentary siliciclastic and carbonate volcanic felsic to intermediate pyroclasts and mantle derived peridotite gabbro serpentinite and serpentine schist rocks the fluvial systems range that transect the betic cordillera are the major detrital source of sediment along the southern spanish coast supplying sand to beaches and offshore depositional systems in the alboran sea basin three key sand petrofacies derived from the betic mountain belt reflect the main clastic contribution of known source rocks all the sands are quartzolithic ranging from quartz rich to lithic rich fluvial systems draining the sierra de los filabres the sierra nevada the sierra de gador and the ma laga mountains and their related beaches constitute a metamorphic sedimenticlastic quartzolithic sand petrofacies qm34610 f463 lt6269 lm72614 lv264 ls26613 derived dominantly from the nevado fila bride alpuja rride and mala guide complexes this quartzolithic petrofacies extends from northeast of almeria to torremolinos southwest of ma laga and northeast of algeciras only one beach sand sample east of cabo de gata is volcanolithic volcanic detritus mainly having felsitic textures is derived from miocene 15 7 ma pyroclastic sequences cropping out in the southeast of the chain this metamorphic sedimenticlastic quartzolithic petrofacies changes in the coastal stretch from torremolinos to marbella where drainage systems cut across the serrania de ronda here source rock types include peridotite gabbro and serpentinite of the ronda peridotite massif and metamorphic rocks of the ma laguide and alpuja rride units the fluvial and beach sands of this area are quartzolithic qm32612 f1063 lt58611 and include abundant peridotite and serpentinite grains the latter quartzolithic petrofacies changes abruptly from algeciras to ca diz where the sand becomes quartz rich qm7765 f462 lt1964 this sand petrofacies is derived predominantly from recycling of sedimentary sequences mainly the quartzarenite turbidite units of the gibraltar arc the algeciras flysch this petrofacies is characterized by higher proportion of quartz grains and abundant sedimentary lithic fragments lm163 lv161 ls9863 the three onshore petrofacies plot in the recycled orogen provenance compositional field and the lithic to transitional to quartzose recycled subfields of dickinson 1985 they vary from lithic to transitional and quartzose depending on their source lithologies in the betic foreland fold thrust belt these actualistic petrofacies best describe the nature and distribution of sand petrofacies derived from a collisional fold thrust belt where primary and recycled source rocks are interfingered deep marine turbidites of the alboran basin have basinwide quartzolithic sands having close compositional relations with betic cordillera onshore sand petrofacies comparison of detrital modes from mainland to deep marine environments provides a suitable basis for interpreting the miocene to pleistocene sand dispersal history in the alboran basin these modern quartzolithic petrofacies are used to interpret analogous ancient collisional sandstone petrofacies of the alpine orogenic belt of the western central mediterranean region and of other collisional orogenic systems as a broader point of view

collision orogen provenance western alps detrital signatures and unroofing trends abstract the alps are perhaps the best studied thrust belt formed during continent continent convergence collision orogen shallow intermediate and deep structural levels can be distinguished within the alpine thrust stack each shedding sediments with distinct petrographic and mineralogical signatures in modern first cycle sands carried by alpine rivers bulk composition rank of metamorphic lithic grains metamorphic index mi and dense mineral assemblages all faithfully mirror the tectono metamorphic history of exposed basement and cover units the shallow structural level widely preserved in the ligurian alps consists of remnant ocean turbidites shedding sedimentary to very low rank metasedimentary detritus documentclass aastex usepackage amsbsy usepackage amsfonts usepackage amssymb usepackage bm usepackage mathrsfs usepackage pifont usepackage stmaryrd usepackage textcomp usepackage portland xspace usepackage amsmath amsxtra usepackage ot2 ot1 fontenc newcomman

p t d histories from quartz a case study of the application of the titaniq thermobarometer to progressive fabric development in metapelites 1 this study investigates the ability of quartz to record segments of the pressure temperature deformation p t d path in poly deformed metamorphic terranes and the associated application of the ti in quartz thermobarometer titaniq metapelites from the strafford dome eastern vermont were selected for this study because they record progressive fabric development during prograde metamorphism and have well constrained p t d histories from previous work results of this investigation are in agreement with previous studies and demonstrate that quartz in these samples records additional distinct intervals of the p t d path six preserved quartz equilibration events include 1 early prograde growth during burial 2 kyanite in quartz producing reactions 3 prenappe emplacement equilibration during isobaric heating 4 precipitation of quartz in quartz feldspar domains during crenulation cleavage development due to solution transfer 5 quartz producing chlorite out reactions during heating postnappe emplacement and 6 retrograde quartz overgrowths from an influx of siliceous fluids modeling quartz volume allows for the identification of quartz producing reactions in p t space the same may be done for ti phases to better constrain activities during reequilibration events an integration of cathodoluminescence imaging microstructural and petrographic investigation isochemical forward stability modeling and thermobarometry allows identification and interpretation of zoning patterns in quartz to unravel histories that would otherwise not be obtainable

compositional evolution of siliciclastic sediments recording the tectonic stability of a pericratonic rift mesozoic kutch basin western india abstract this study presents a combined petrographical and geochemical investigation to track the compositional changes in the mesozoic sedimentary record during the evolution of the pericratonic rift basin of kutch the mesozoic sequence of the proven petroliferous basin of kutch representing 3000 m thick siliciclastic and carbonate deposition within a time frame of 70 ma consists of jhurio jhumara jhuran and bhuj formations in ascending order of succession the dominance of arkosic sandstones and the abundance of zircon and monazite indicate predominantly felsic source rocks the concentration of individual trace elements such as th sc zr v ni and ratios like th sc cr v y ni th co la sc support the predominantly felsic source rock the lree enrichment and the negative eu anomaly corroborate the predominantly felsic source however concentrations of v ni and ti reveal the mafic input in older stratigraphic units while gdn ybn indicates dominant post archean source across the mesozoic succession younger stratigraphic units reveal contributions from the archean rocks from nagar parkar and aravalli highland regions the cia values suggest intermediate to intense weathering while the icv data record a shift from immature sediments in the older formations to mature and recycled types in the younger formations the high value of zr sc as well a high content of hf reflects the addition of zircon by recycling or by erosional unroofing of older continental rocks major oxide sio2 na2o and k2o and trace elements la th and hf bear the passive margin setting for the kutch basin during the mesozoic the decrease in feldspar content in sandstones increase in the concentration of zr and hf in shale and a decrease in values of icv from older to younger stratigraphic units corresponds to the compositional evolution related to increased stability of the kutch basin during the transition from early syn rift to post rift

the 4 d microgravity method for waterflood surveillance a model study for the prudhoe bay reservoir alaska forward and inverse gravity modeling is carried out on a suite of reservoir simulations of a proposed water injection in the prudhoe bay reservoir alaska a novel surveillance technique is developed in which surface gravity observations are used to monitor the progress of a gas cap waterflood in the reservoir at 8200 ft 2500 m depth this cost effective method requires that high precision gravity surveys be repeated over periods of years differences in the gravity field with time reflect changes in the reservoir fluid densities preliminary field tests at prudhoe bay indicates survey accuracy of 5 10 gal can be achieved for gravity data using a modified lacoste romberg g type meter or scintrex cg 3m combined with the navstar global positioning system gps forward gravity modeling predicts variations in surface measurements of 100 gal after 5 years of water injection and 180 250 gal after 15 years we use a constrained least squares method to invert synthetic gravity data for subsurface densi

the piermont allochthon revisited and redefined at its type locality discussion timms 2004 1 has made a significant contribution to understanding a controversial structural feature of central new england the piermont allochthon see hadley 1942 2 1950 3 rumble 1969 4 moench 1990 5 1992 6 1996 7 1999 8 billings 1992 9 rankin 1996 10

provenance signatures recorded in transgressive sandstones of the upper cretaceous iberian seaway abstract maximum mesozoic transgressions flooded many continental areas worldwide forming a wide and shallow seaway on the iberian microplate during the late cretaceous several siliciclastic and mixed siliciclastic carbonate units developed along the iberian massif cratonic area while at the same time epeiric carbonate platforms spanned iberia these siliciclastic deposits unconformably cover the variscan basement as well as the permian and triassic deposits this study focuses on sandstone provenance in central spain in a transgressive relatively quiet tectonic setting with a wide rock variety in the potential source areas results shown in this paper can be applied in analogue systems transgressive sandstones often form important hydrocarbon reservoirs due to their high primary porosity the cretaceous siliciclastic deposits are included in four formations ranging in age from the cenomanian to the early coniacian the deposits were initially of fluvial origin followed by a coastal tidal setting quantitative petrographic analysis of sandstones from these formations reveals compositional variations related to provenance and weathering degree the oldest formation utrillas fm was deposited on a paleorelief surface sandstone composition changes from arkosic sandstones in the depressed area petrofacies p1a to younger quartzarenites when sediments were deposited on top of the paleotopographic high petrofacies p1b quartz grains in both sub petrofacies are angular to subangular and the framework is poorly sorted intense weathering conditions are deduced for petrofacies p1b manifested by grain infiltration clay coatings and the absence of plagioclase grains and alteration features on k feldspars all these observations have been related to wetter conditions during p1b deposition main source areas of the utrillas fm were ordovician metasediments and orthogneisses permian volcanic rocks and triassic buntsandstein facies petrofacies 2 encompasses the three coastal tidal formations constituted mainly by subarkoses generally showing a subangular and poorly sorted framework the deduced source areas are mainly associated with variscan granitoids pre ordovician schists and paragneisses and ordovician metasediments glauconite and carbonate grains support intrabasinal inputs the low degree of sorting of this petrofacies related to a low energy sedimentary environment produced lower values of original porosity compared to transgressive sandstone hydrocarbon reservoirs also intrabasinal inputs promoted carbonate cementation and contribute to almost occlude the porosity

4d gravity response of compacting reservoirs analytical approach abstracttime lapse gravity is a technique sensitive to subsurface change in mass and in mass distribution we attempted to devise a method to predict gravity effects caused by redistribution of subsurface mass induced by reservoir compaction first displacements and strains due to compaction were modeled using a geomechanical model then 4d gravity effects were derived from the displacements and the volumetric strains computed in and around the reservoir a sensitivity study was carried out for geomechanical parameters such as poisson s ratio as well as for geometrical parameters such as reservoir radius and depth finally changes in gravity due to compaction were compared to changes induced by reservoir fluid substitution given a rigid basement close below a strongly compacting reservoir our modeling case showed that the deformation itself could give gravity changes comparable to changes caused by reservoir fluid density changes which are the changes traditionally targeted by gravity monitoring

the effects of source lithology transport deposition and sampling scale on the composition of southern california sand the transverse ranges of southern california represent an uplifted and variably dissected mesozoic magmatic arc and mesozoic to holocene sedimentary and volcanic strata deposited in convergent and transform tectonic settings modern sand within part of the western transverse ranges represents first order sampling scale of the santa monica and the san gabriel mountains second order sampling scale of the santa clara river draining both mountain ranges and third order sampling scale of the beach system between the mouth of the santa clara river and the eastern santa monica mountains and turbidite sand of the hueneme mugu submarine fan source lithology includes plutonic and metamorphic rocks of the san gabriel mountains and sedimentary and volcanic rocks of the santa monica mountains first order sands have large compositional variability sand from local coastal drainage of the santa monica mountains ranges from basaltic feldspatholithic to quartzofeldspathic sand of the san gabriel mountains local drainages has three distinct petrofacies ranging from metamorphiclastic feldspatholithic to mixed metamorphi plutoniclastic and plutoniclastic quartzofeldspathic second order sand is represented by the main channel of the santa clara river the sand has an abrupt downstream compositional change from feldspathic to quartzofeldspathic third order sand beaches and deep sea turbidite samples of the santa monica basin is quartzofeldspathic beach sand is more quartz rich than is santa clara river sand whereas turbidite sand is more feldspar rich than is beach sand deep sea sand has intermediate composition with respect to second order samples of the santa clara river and third order samples of the beach system suggesting that 1 the santa clara river is the main source of sediments to the marine environment and 2 local entry points from canyons located near local drainages may generate turbidity currents during exceptional flood conditions petrologic data of modern sand of the study area are highly variable at first and second order scale whereas third order sand is homogenized the homogenized composition of deep marine sand is similar to the composition of most ancient sandstone derived primarily from the mesozoic dissected magmatic arc of southern california this study of the western transverse ranges illustrates the effects of source lithology transport depositional environment and sampling scale on sand composition of a complex system which provides insights regarding actualistic petrofacies models

facies control on sandstone composition and influence of statistical methods on interpretations in the john henry member straight cliffs formation southern utah usa abstract the upper cretaceous john henry member of the straight cliffs formation preserves regressive shoreface and channel facies and transgressive lagoonal tidal inlet facies that suggest distinct modal sandstone compositions detrital modes from six sandstone facies upper shoreface lower shoreface deflected mouth bars fluvial channels tidal inlets and washover fans and their spatial and temporal variations provide additional data regarding the depositional environments and setting of the john henry member three statistical methods were utilized univariate standard deviation and confidence interval and multivariate logratio transformations to assess the compositional difference between facies using estimation of means both univariate statistical methods have some inherent problems standard deviation does not account for sample size while the confidence interval method incorporates a t test to account for only some of the uncertainty of small sample size the results of the univariate methods differ slightly and both indicate statistically distinct sandstone compositions based on facies multivariate statistics are much more robust and suggest similar trends yet display different compositional means and have inconclusive confidence fields as they incorporate all of the uncertainty associated with small sampling sizes in general sandstone compositions become more quartz rich and compositionally mature as sediment is transported from proximal fluvial environments to distal upper shoreface environments this trend reflects the degree of preferential reworking or winnowing of unstable grains prior to lithification more complicated relationships are observed as facies distributions shift through space and time sandstone compositions support a deflected wave dominated deltaic interpretation for the john henry member in this area sandstone compositions become more lithic rich from north to south corresponding to the facies distribution of upper shoreface and deflected mouth bars respectively mouth bars occur at the intersection of the fluvial channel and the coastline where sand is deflected via longshore drift to the southern portion of the field area upper shoreface facies located further away from mouth bar facies are heavily reworked by wave processes and contain more mature quartz rich modal compositions additionally high feldspathic and lithic concentrations in tidal inlet facies suggest that this facies was sourced closer to mouth bars rather than updrift upper shoreface sediments a shift in sandstone composition occurs at the end of the second transgressive regressive cycle of the john henry member throughout the rogers canyon area this compositional change is concurrent with a relatively large basinward shift in facies which suggests that it reflects the transition from regressive to transgressive facies associated with the relative sea level fall rather than a change in the main sediment source area

sand composition in an iberian passive margin fluvial course the tajo river the tajo river the 10th largest river in europe drains part of the western passive margin of europe that includes multiple tectonic elements of the iberian plate modern fluvial sand composition in the tajo river drainage basin reflects the nature of the source region which lies in the central part of the iberian peninsula four fluvial petrographic provinces a b c and d can be established in the tajo drainage basin corresponding well with the four principal structural units drained 1 the iberian range 2 the hesperian massif 3 the tertiary tajo basin and 4 the neogene santarem lisboa basin province a corresponds to the tajo river head and is characterized by quartzolithic sedimenticlastic sands qm67f4lt29 and rs79rg3rm18 these sands have been derived from diverse mesozoic siliciclastics and carbonates of the iberian range province b appears in the upper reaches of the tajo river course and is quartzofeldspathic qm57f34lt9 with diverse rock fragments rs34rg23rm43 sources are hercynian granitoids and metasediments and neogene clastics and minor carbonates of the tertiary tajo basin province c extends along the middle course of the tajo river with quartzofeldspathic metamorphiclastic sand modes qm60f33lt7 rs4rg21rm75 the sources are metamorphic rocks intruded by plutonites of the hesperian massif province d is quartzofeldspathic qm55f39lt6 with a dominance of phaneritic rock fragments rs5rg33rm62 and corresponds to the lower reaches of the tajo river where siliciclastic deposits of the neogene santarem lisboa basin are the main sources sands plot on provenance discrimination diagram qmflt within the recycled orogen field tajo river head and continentalblock fields upper middle and lower course in addition we have proven the usefulness of the rsrgrm diagram to discriminate the defined fluvial provinces originating from heterogeneous parent rock textures and mineralogy climate does not exert any strong influence on the petrogenesis of the tajo river drainage basin sand and erosion in the source areas may be described in terms of weathering limited denudation regime by contrast mixing with tributary supplies is the main process that modifies composition in the tajo river sand the establishment of fluvial provinces related to the main bedrock structural units reflects the great relevance of tributaries from each province in the generation of the tajo river sand and the low significance of inherited sandy load from previous provinces the abundance of granitoid rock fragments rsrgrm rg in fluvial sand of both tributaries and main channel of the tajo river drainage basin faithfully represents the relative abundance of granodiorite monzogranite bedrock exposure in each subbasin metasedimentary and metamorphic bedrock outcrop area is overrepresented by metamorphic rock fragments rsrgrm rm in both sand from tributaries and from the tajo main trunk river this is manifested by differences of 18 23 between means of metasedimentary outcrop area and the rsrgrm rm mean in the sand from provinces b and c d respectively sedimentary mainly carbonate outcrop area is underrepresented or not represented by sedimentary rock fragments rsrgrm rs in sand of the tajo river this underrepresentation causes a difference between means of sedimentary outcrop area and the rsrgrm rs mean of 21 17 1 and 10 7 in sands from province a b and c d respectively this fact confirms the rapid loss of these grains during transport because of their labile nature

possible paleostress tensor configurations derived from fault slip data in eastern vermont and western new hampshire the configuration of six possible paleostress tensors have been derived from 152 faults measured in eastern vermont and western new hampshire populations of potentially genetically related faults were separated using two techniques tensor configurations for each population were derived using a linear least squares inversion method based in part on the work of reches 1987 and a grid search inversion method which tests over 100 000 possible tensors for compatibility with all or portions of the data faults belonging to the oldest population set r n 24 occur primarily in high grade rocks this set is composed of semiductile northeast trending reverse and west northwest trending left lateral faults fault fabrics of quartz rods and thin mylonite layers suggest that the host rocks were at crustal levels of 8 10 km during faulting the derived tensor indicates a roughly east west 1 and near vertical 3 set r faults are offset by normal faults sets n1 and n2 and are interpreted to be pre mesozoic in age perhaps related to late paleozoic alleghanian compression normal and normal oblique faults mineralized with chlorite calcite and strained quartz n 73 have been separated into two populations sets n1 n 49 and n2 n 24 even though these faults are likely of similar age host rocks were probably at moderate crustal depths of perhaps 5 km during faulting faults of both sets are most likely related to mesozoic rifting tensor configurations indicate that 1 plunges steeply northwest n1 and southeast n2 and 3 plunges gently roughly east west these faults cut presumably mesozoic age dikes and are themselves offset by normal oblique faults set t and right lateral faults set rl strongly deviatoric near vertical 1 suggests a thermally driven tectonic regime during the development of normal faulting in new england set t n 25 is composed of normal oblique slip faults mineralized similarly as sets n1 and n2 the plunge of 1 is 50 n and 3 plunges gently east field relations indicate set t faults document the transition from normal sets n1 and n2 to strike slip faulting regimes set rl a compatible sequence of mesozoic stress fields is suggested de boer et al 1988 north northeast trending right lateral faults of set rl n 7 are mineralized with quartz limonite calcite chlorite calcite twins are bent and fractured and quartz grains show minor internal strain suggesting that these faults developed while host rocks were at relatively shallow crustal levels the plunge of 1 is gently northeast and 3 plunges gently east southeast seven distinctly mineralized feldspar siderite quartzoalcite 1imonite chlorite gently northwest dipping thrust faults of set f define the sixth tensor these faults are cut by essentially vertical east side up faults and are assumed to be mesozoic in age by analogy with similar faults in western massachusetts

the effects of source rocks and chemical weathering on the petrogenesis of siliciclastic sand from the neto river calabria italy implications for provenance studies plutonic and gneissic rocks of the sila massif in the uppermost portion of the neto drainage basin calabria southern italy weather and erode under a humid mediterranean climate during the development of weathering profiles a combination of chemical weathering and granular disintegration processes occurred chemical weathering involves a loss of both plagioclase mainly during grus generation and k feldspar mainly during soil formation this loss is attributed to transformation of plagioclase to clay minerals and to leaching and dissolution of k feldspar sand composition is quartzofeldspathic and nearly homogeneous along the main channel of the neto river even where the river cuts across a blanket of sedimentary cover thus fluvial transport does not alter sand composition within the neto drainage basin petrographic indices are effective in 1 discriminating between contributions from similar granite and gneiss source rocks qm f 2 relating the provenance of plutoniclastic and gneissiclastic sand found in the headwaters to grus horizons qm f q rg and 3 distinguishing between upstream first cycle and downstream multicycle sand q rg this last distinction is further emphasized by considering both aphanitic and phaneritic varieties of rock fragments rgrmrs diagram chemical weathering is the main sand producer within the regolithic environment in northern calabria in addition rapid erosion resulting from steep slopes removes weathered products and rapid and short transport leads to minimal sediment maturation in general the f q index is climate and relief dependent thus it should be used in conjunction with palaeoclimatic and palaeophysiographic evidence for provenance interpretations of ancient quartzofeldspathic sandstones

provenance of sand on the poverty bay shelf the link between source and sink sectors of the waipaoa river sedimentary system abstract the poverty shelf north island new zealand is a segment of the waipaoa sedimentary system wss a margins source to sink focus site our petrographic analysis of sand from shelf core samples indicates that the sand fraction is mainly derived from intra and potentially extrabasinal sources but surprisingly the major fluvial system that drains into poverty bay the waipaoa river mean qfl xqyfzl is not the dominant source only one vibracore at the mouth of poverty bay contained sand qfl xqyfzl potentially derived from the waipaoa river the shelf sand mean qfl xqyfzl more strongly resembles beach sand mean qfl xqyfzl collected along the coast which is likely sourced from pervasive local cliff erosion of miocene pliocene sedimentary units that exhibit similar sandstone detrital modes mean qfl xqyfzl texturally coarser more poorly sorted and more angular sand is located along the outer shelf while finer well sorted sand characterizes the mid shelf these findings suggest a shorter transport history for the material near the outer shelf bathymetric high areas and this observation along with the composition data suggests that they were sourced by erosion of locally exposed miocene pliocene units a potential extrabasinal source of shelf sediment is indicated by anomalous prolate and equant shaped greywacke torlesse and minor red chert pebbles collected in two outer shelf box cores on the lachlan anticline these are not lithologies found within the terrestrial segment of the wss or strata comprising the outer shelf highs the clast shapes are also distinctly different from the oblate shaped pebble sized greywacke gravel clasts on beaches in hawke bay rather these sediments are more similar to torlesse stream gravel seismic and multibeam data support the possibility that during the most recent sea level lowstand the hawke bay fluvial system flowed into poverty canyon bringing these unique gravels onto what is now the poverty outer shelf the presence of the torlesse gravel is significant in that it highlights how the wss was not a closed sedimentary system in the past just as recent sedimentary research has shown in the case today

a new sea floor gravimeter a new reservoir management application uses precise time lapse gravity measurements on the sea floor to detect seawater infiltration in offshore natural gas fields during production reservoir models for the north sea troll field predict gravity changes as large as 0 060 mgal within a 3 5 year period we have constructed and deployed a new instrument the rovdog remotely operated vehicle deployed deep ocean gravimeter system for this application because the measurements must be relocated accurately within 3 cm we required a gravimeter which could be handled by an rov and placed atop sea floor benchmarks we have built an instrument based upon the scintrex cg 3m land gravimeter motorized gimbals level the gravimeter sensor within a watertight pressure case precision quartz pressure gauges provide depth information a shipboard operator remotely controls the instrument and monitors the data the system error budget considers both instrumental and field measurement uncertainties the instrument prototy

evolution of the western continental margin french italian alps sandstone mineralogy as an index of plate tectonic setting most plate tectonic developmental models for the western or french italian alps show that the western or french continental margin of the tethyan locally piedmont ocean exhibited several contrasting types of structural behavior from late paleozoic through tertiary time initially this margin acted as a rifted passive progressively subsiding atlantic type margin from late paleozoic through jurassic time during the cretaceous and tertiary active volcanism blueschist metamorphism and indications of rapid uplift and erosion suggest that active subduction of the piedmont and valais ocean basin s occurred producing a himalayan like sutured orogenic highland local island arc trench inland sea systems and possibly even transform faults all characteristics of orogenically active continental margins like those of the modern mediterranean and around the perimeter of the present day pacific ocean compiled analyses of modern sands from present day ocean basins and continental margins have been used

the piermont allochthon revisited and redefined at its type locality discussion timms 2004 1 has presented a very restricted interpretation of an important structural feature in the new england appalachians that i originally termed the piermont allochthon and interpreted as a far traveled acadian thrust sheet moench et al 1987 2 moench 1990 3 as described

transient salt transport modeling of shallow brine beneath a freshwater lake the sea of galilee israel during a lake highstand phase in the late pleistocene the former saline lake lisan covered the topographic depression of kinarot basin currently occupied by the freshwater lake sea of galilee it was hypothesized that during this period the dense saline waters of lake lisan percolated into the sediment the recession of the saline lake from the basin and the rapid formation of a freshwater lake triggered solute transport from the sediment into the lake a one dimensional numerical model of solute transport that considers sediment compaction was developed to simulate chloride transport from the sediment into the lake simulation results were compared with measured chloride concentration profiles in sediment cores on the basis of a sensitivity analysis results are in agreement with the hypothesis that lake lisan solutes are currently discharged into the sea of galilee the calculated upward water velocity in the sediment ranges between 9

sourceland controls on the composition of beach and fluvial sand of the northern tyrrhenian coast of calabria italy implications for actualistic petrofacies abstract the northern tyrrhenian margin of calabria in southern italy provides a natural laboratory for sampling sand at different scales small drainages first order rivers draining mountain ranges second order and marine environments beach to deep marine third order calabrian mountain ranges represent an uplifted and variable dissected thrust belt constituted by palaeozoic through pleistocene plutonic metamorphic ophiolitic carbonate and siliciclastic rocks the modern setting includes a mountainous coast having high rates of fluvial discharge and the deep marine paola basin the composition of modern fluvial and beach sands is useful for the interpretation of sediment transported into deeper water environments modern beach and fluvial sands of the northern tyrrhenian margin of calabria define three distinct petrologic provinces from north to the south 1 the lao littoral province has calclithite sand derived from erosion of dominantly carbonates of the southern apennines 2 the coastal range littoral province has quartzolithic sand derived from dominantly metamorphic schist and phyllite coastal range and 3 the santa eufemia littoral province has quarzofeldspathic sand derived from dominantly metamorphic coastal range and sila massif and plutono metamorphic mount poro provenances deep marine turbidites of the paola basin have basinwide quartzolithic turbidite sands having close compositional relations with coastal range littoral petrofacies only at the northern boundary of the paola basin calclithite turbidite sand record deep water dispersal of the lao littoral sands comparison of detrital modes from mainland to deep marine environments contribute to the models of dispersal pathways and geographical extension of actualistic sand petrofacies

provenance of mesozoic to cenozoic circum mediterranean sandstones in relation to tectonic setting abstract the composition and stratigraphic relations of clastic strata in diverse sedimentary basins of the circum mediterranean region reflect a complete record of provenance relations since break up of pangea neo tethyan taphrogenesis and subsequent plate convergence between the two major plates of europe and africa and other related microplates of iberia adria mesomediterranean and toward to the eastern mediterranean the anatolian microplate since plate reorganization after the breakup of pangea at the end of paleozoic earliest mesozoic clastic wedges filled sedimentary basins within geodynamic settings evolving from intracontinental rifts rifted continental margins protoceanic basins arc trench basin systems remnant ocean basins foreland basin systems and intramontane and back arc basins within the circum mediterranean region the changing nature of clastic particles in these clastic wedges reflect the provenance relations from different source rocks within the spatial and temporal evolving geo puzzle terranes including relations between ophiolite bearing uplifted continental crust both shallow to deep crust terranes volcanic and sedimentary particularly carbonate strata source rocks mixed siliciclastic and carbonate shallow to deep marine clastic wedges are diffuse in many filled basin systems along the mediterranean as such as occurrence of volcaniclastic layers interbedded with siliciclastic wedges the variable mosaic of source terranes within the mediterranean region offered the possibility to investigate provenance relations with a new plane of precision and sophistication discriminating grain particles in clastic wedges using spatial extrabasinal versus intrabasinal and temporal coeval versus noncoeval distinction of detrital signals the spatial temporal approach in deciphering particles in clastic rocks has been widely used to detail the basinal dispersal pathways in different geotectonic settings wherever mixed silicate and carbonate terranes act as the major source rocks from rifted continental margins to collisional orogens

geochemistry of asara shale member of karaj formation central alborz iran provenance source weathering and tectonic setting abstract the asara shale member of the karaj formation middle to upper eocene in age includes mixed volcaniclastic siliciclastic and carbonate strata in the alborz mountains northern iran these strata have been geochemically analyzed to constrain their source area provenance most of the major and trace element contents of asara shale samples are generally similar to the upper continental crust ucc values and their chemical index of alteration cia values 31 7 50 9 suggesting a semi arid climate in a weathering limited source area moreover correlation of major element oxides suggests the controlling effect of plagioclase and clay minerals on these data when xrd analysis and sem images indicate clastic sourced illite and chlorite in the samples probably due to the weathering of volcanic ash and glass in an aqueous transport and depositional environment however the chondrite normalized ree plot of mudrocks of the asara shale show a similarity with the ucc composition mineral composition and geochemistry of the asara shale mudrocks reveal the rapid reworking of penecontemporaneous volcaniclastic deposits which had covered the surrounding areas instead of their epiclastic genesis related to erosion and transport major trace and rare earth element ree data imply a felsic composition of the volcanic source related to an active continental margin continental island arc and most probably back arc tectonic setting for the depositional basin inferring a mid upper eocene extensional volcanism in a subduction complex

provenance and paleodrainage patterns of upper jurassic and lower cretaceous synrift sandstones in the flemish pass basin offshore newfoundland east coast of canada upper jurassic to lower cretaceous synrift sandstones from two industry exploratory wells in the flemish pass basin were studied for provenance using heavy mineral proxies these sandstones were deposited during the north atlantic rifting stage at which time rifting intensified between iberia and the grand banks several heavy mineral methods were used including in situ u pb geochronology and morphological and chemical analysis of detrital zircons chemical discrimination of detrital tourmalines and heavy mineral ratios clastic bed load material entering the northern flemish pass basin during the tithonian to berriasian was connected to transport systems reaching west as far as 400 to 500 km 249 311 mi source areas to the west included igneous rocks and associated cover sequences of the avalon zone as well as the magmatic rocks metasedimentary rocks and associated cover sequences present in the central mobile belt the eastward directed input of bed load material into the basin is considered to have resulted in the concentration of sandstone units along its western margin with deteriorating reservoir grade toward the east given the regional extent of drainage systems it is likely that similar constraints apply to equivalent sandstones in the adjacent east orphan basin by the valanginian barremian paleodrainage orientations had switched and bed load material began to enter the flemish pass basin from more proximal areas to the southeast with the avalon zone basement overall no evidence exists to support sediment sourcing from the iberian margin or the flemish cap galicia bank continental fragment to the east and material from these areas is instead interpreted to have been shed into the incipient atlantic ocean or bay of biscay also no evidence exists to support sourcing from grenville basement farther to the west implying that a drainage divide may have existed somewhere between central and western newfoundland west of which material was presumably being transported to the south or southwest

provenance evolution and unroofing history of a modern arc continent collision evidence from petrography of plio pleistocene sandstones eastern taiwan abstract plio pleistocene sandstones from the coastal range of eastern taiwan provide a record of shifting source areas and unroofing events in adjacent arc and accretionary wedge terranes during the early stages of are continent collision in latest miocene and early pliocene time arc derived sediments were deposited in a precollisional forearc basin between the luzon volcanic arc and the manila trench sandstones of this age are rich in zoned plagioclase volcanic lithic fragments and pelagic foraminifera and contain only minor quartz and sedimentary metasedimentary lithic fragments in contrast lower pliocene to lower pleistocene sandstones are poor in feldspar and volcanic fragments and contain abundant sedimentary and metasedimentary lithic fragments this reflects a provenance shift f om the volcanic arc to the uplifted meta sedimentary accretionary wedge of proto taiwan which resulted from the early pliocene onset of arc continent collision a refined classification of sedimentary and metasedimentary lithic fragments is introduced here and used to interpret the early evolution of the collisional orogen lithic fragments are rich in pelitic minerals and are divided into 1 sedimentary ls mudstone shale siltstone chert and argillite 2 low grade metamorphic lm1 slate slatey siltstone and quartzite and 3 medium grade metamorphic lm2 phyllite schist phyllitic quartzite and quartz mica albite aggregate a good correlation is observed between these lithic fragment types and bedrock lithologies exposed in the present day central range of taiwan based on this correlation the change in relative abundance of sedimentary and metasedimentary lithic fragments through time has been used to interpret an unroofing sequence for the collisional fold and thrust belt lower pliocene taiwan derived sandstones are rich in sedimentary lithic fragments ls which were shed from the accretionary wedge during the earliest stages of arc continent collision from early pliocene to early pleistocene time sandstones became progressively depleted in ls lithic fragments and enriched first in lm1 and later in lm2 fragments as deeper levels in the metamorphic complex were uplifted and exposed to erosion regional metamorphism of biotite grade rocks lm2 occurred at about 4 5 ma at depths of 12 15 km ernst 1983 and were uplifted to the surface by about 1 4 ma this study these ages give an uplift rate of 4 to 5 km m y which is in good agreement with independent estimates based on fission track studies raised coral reefs quaternary elevation changes and present day denudation rates thus it appears that sandstone detrital modes of clastic orogenic sequences can be used to interpret specific aspects of unroofing and tectonic evolution in nearby active mountain belts

feasibility analysis for time lapse seafloor gravity monitoring of producing gas fields in the northern carnarvon basin offshore australia abstracthighly accurate seafloor gravity data can detect small density changes in subsurface hydrocarbon reservoirs by precisely repositioning the gravimeters on the seafloor in producing gas fields these small density changes are primarily caused by production related changes to the pressure and gas fluid saturations in the reservoir pore space knowledge of the pressure and saturation changes is vital to optimize the gas recovery especially in offshore environments in which wells are expensive and sparse we assessed the feasibility of time lapse seafloor gravity monitoring for the giant gas fields in australia s premier hydrocarbon province the northern carnarvon basin we determined that gravity monitoring is more feasible for reservoirs with a large areal extent and or shallow burial depths with high porosities and high net to gross sand ratios forward modeling of the gravity responses using simple equivalent geometry shapes and full 3d complex heterogeneous models predicted that density change

the oligocene ophiolite derived breccias and sandstones of the val marecchia nappe insights for paleogeography and evolution of northern apennines italy abstract ophiolite derived debrites microbreccias and olistoliths are interbedded in the monte morello and argille varicolori formations of the val marecchia nappe constituting the highest tectonic unit of the north eastern apennines and usually considered as having originated from the external ligurian domain the ophiolite derived clastic rocks were supplied exclusively by an oceanic sequence consisting of peridotite gabbro basalt radiolarite pelagic limestone and shale they are interbedded within a succession made up of fine grained carbonate and siliciclastic turbidites and of pelagic claystones petrographic and sedimentological features of the ophiolite derived breccia and sandstone units testify to an intrabasinal source area for these clastic rocks rather than an extrabasinal origin from subaerially exposed oceanic crust forming the inner flank of the basin as previously suggested due to their oligocene earliest miocene age the deposits in which debrites and olistoliths occur are related to early neo alpine tectonic events that caused reactivation and or inversion of old normal transform faults unstable fault escarpments provided a preferential path for submarine landslide and turbidite emplacement debrites microbreccias and olistoliths therefore were added to the basin fill of fine grained turbidite and pelagic deposits this study suggests that the val marecchia nappe succession was deposited on an oceanic substratum stratigraphy and age of the succession of this nappe can be well framed only in the evolution of the sub ligurian domain whereas they conflict with the interpretation of the val marecchia nappe as a nappe originated from the external ligurian domain as suggested previously by most authors this interpretation also requires an oceanic substratum for the sub ligurian domain i e the existence of an oceanic belt external to the ligurian domain which was deformed only in the early miocene the sub ligurian domain therefore would be an eastern branch of the central tethys and would represent the extension in the northern apennines of the maghrebian lucanian oceanic realm as recognized in the betic cordillera maghrebian chain and southern apennines

gravimetric monitoring of gas production from the troll field four surveys of relative gravity and depth measurements have been conducted over the troll field since gas production began in 1996 precision in gravity intrasurvey repeatability measured as standard deviation has improved from 26 gal to 4 5 gal in two surveys in 2002 and 2005 the scatter of 74 station depth differences standard deviation has improved to 1 0 cm with modeled subsidence removed for the same two surveys subsidence of up to 3 cm is observed above the thickest reservoir of troll east between 2002 and 2005 time lapse gravity shows a general slight average increase in troll east 95 confidence for the interval centered at 5 2 4 4 gal which is likely caused by edgewater influx one gravity station close to troll a shows a 9 gal gravity increase indicating 2 2 m water rise repeated logging in a nearby well indicates 2 8 m rise these two observations agree within uncertainty bounds gravity decrease in troll west is explained by oil production and a downward moving gas oil con

tectonic evolution of the southern apennines thrust belt italy as reflected in modal compositions of cenozoic sandstone the composition of sandstones derived from erosion of the southern apennines orogen provides constraints for cenozoic tectonic evolution clastic wedges were derived mainly from the strongly deformed calabrian arc allochthon this key tectonic element is interpreted as a thrust sheet of european crust moved about 300 400 km eastward during the paleogene to neogene toward the adria foreland during the paleogene to early miocene the liguride complex oceanic terrane was deposited in a remnant ocean basin east of the calabrian arc related to northwestward subduction of ligurian oceanic lithosphere beneath the european margin upper paleogene quartzofeldspathic and volcanolithic liguride sandstones testify to provenance from the subduction complex to the magmatic arc respectively upper oligocene to lower miocene quartzolithic sandstone suggests a recycled orogen provenance i e metasedimentary rocks in the growing accretionary calabrian arc final closure of the liguride remnant ocean basin and onset

sandstone petrology and provenance of the siwalik group northwestern pakistan and western southeastern nepal abstract the siwalik group consists of a neogene sedimentary succession 5 8 km thick deposited as the himalayan foreland basin developed following collision between the indian and eurasian continents it consists of fluvial deposits composed of shale siltstone and sandstone in the lower part and thick sandstone and conglomerate in the upper part this paper presents new petrologic data on the sandstone composition of two coeval petrofacies of siwalik group in two areas the potwar plateau of northwestern pakistan and the surai khola and bakiya khola localities of western and southeastern nepal in both regions detrital modes reflect a collisional orogen provenance petrologic parameters indicate derivation from mid crustal rocks and overlying sedimentary strata ascribed to different tectonostratigraphic units of the high himalaya and tibetan zone the siwalik sandstones of the potwar plateau nw pakistan are composed of low to medium grade metamorphic and sedimentary detritus and subordinately of ophiolitic and volcanic detritus abundant metamorphic detritus consists of phyllite fine grained schist lithics and coarse grained gneiss derived from the high and or lesser himalaya sedimentary detritus is represented by abundant limestone radiolarian chert siltstone shale very fine grained quartzarenite and other sandstone grains the siliciclastic grains probably were eroded from older terrigenous sequences belonging to the tethys himalayan and lesser himalayan zones uplifted during the india eurasia collision ophiolitic volcanic lithic grains and radiolarian chert reflect a provenance from the indus suture and tran himalayan belt the sandstones of western and southeastern nepal surai khola and bakiya khola sections have higher quartz and lower feldspar contents than those of northwestern pakistan and contain sedimentaclastic western nepal and metamorphiclastic sandstones southeastern nepal comparison of the data presented here with previous work on pre and post siwalik sandstones of the himalaya range and of the remnant ocean basins along both sides of the indian peninsula also derived from the himalayan suture belt suggests abundant quartzolithic detritus from the eocene to the present varying proportions of lithic populations in time are related to rapid uplift of the himalayas and intense unroofing of sedimentary metasedimentary and deeper terranes

metamorphic p t paths from calcic pelitic schists from the strafford dome vermont usa metamorphism of the gile mountain formation and waits river formation in the strafford dome and townshend brownington syncline in east central vermont records two nappe style events d1 and d2 followed by doming d1 formed a muscovite biotite ilmenite schistosity subparallel to compositional layering so and was followed by heating to garnet grade the temperature and pressure at the end of d1 are estimated to be c 450d c and 6 8 kbar d2 variably crenulated and folded s1 during a nearly isothermal pressure increase of 1 2 kbar calculated from compositions of garnet which have inclusions trails with progressive crenulation and rotation of the s1 fabric similar p t paths are computed for most of the area suggesting that the later schistosity developed during emplacement of a regional nappe 3 6 km thick there is a general lack of d3 dome stage microstructures near the strafford willoughby arch staurolite and kyanite overgrew s2 in pelites and plagioclase with increasing xan overgrew s2 in calcic pelites reflecting post d2 heating to a maximum of 550 600d c metamorphic pressures at the end of d2 are fairly constant on the west side of the dome indicating minor dome stage uplift in contrast pressures at the thermal peak of metamorphism decrease by more than 4 kbar east of the dome the observed pattern of isotherms and isobars is mainly the result of post metamorphic differential uplift and unroofing finally a minor retrograde metamorphism produced the assemblage albite epidote k feldspar muscovite chlorite with grade increasing east toward the connecticut river

gravity changes and natural gas extraction in groningen gravity observations made over the groningen gasfield from 1978 onwards are available the existing gravity data were reanalysed and a new survey was carried out the observed gravity changes obtained during four surveys spanning an 18 year period were compared with the gravity effect due to natural gas extraction computed from the reservoir model and the production data the random error in the gravity values is small enough to detect the effect of gas extraction after a few years up to 2 gal year the trends obtained from observed and calculated gravity changes agree well within their expected error margins after statistical data snooping due to the inadequate measurement set up of the previous surveys systematic errors present in the gravity data hampered the use of this data for refinement of the reservoir and the production models however with improved gravity monitoring in particular a very systematic network set up and well calibrated instruments this should now be feasible by using the network analysis from the 1996 measurements for the planning of a network in space and time most of the current problems can be avoided

provenance of volcaniclastic beach sand in a magmatic arc setting an example from lipari island aeolian archipelago tyrrhenian sea lipari an active volcanic island in the aeolian magmatic arc is an excellent area to determine the effects of multiple source lithology climate weathering transport and depositional environment on epiclastic sand composition volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the gazzi dickinson method and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using gis several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized and divided into two categories of provenance lithotypes lavas and pyroclastic rocks ranging in composition from basaltic andesitic to andesitic to rhyolitic volcanic lithic fragments from lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork felsitic vitric and microlitic textures moreover high amounts of detrital less durable minerals such as pyroxene olivine and fe oxides illustrate how the analysed sands preserve the source rock s provenance signals applying the concept of sand generation index we see that these lithotypes have different propensities to create detritus in terms of both grain size and composition clastic contribution from pyroclastic rock outcrops such as pumice is not found in the size ranges studied suggesting that these pumiceous source rocks probably only produce gravel or very fine sand and silt this finding has implications for the stratigraphic record because pumice clasts ranging from medium to fine grain size could be underrepresented in older volcaniclastic deposits and overrepresented in other size fractions

paleostress analysis of atlantic crustal extension in the quebec appalachians abstract a paleostress analysis using normal fault slip data and jurassic dike trends has been conducted in the quebec and new england appalachians stress tensor analysis of fault slip by a numerical inversion method has distinguished homogeneous and directionally consistent e w and nw se oriented extensional stress regimes in the quebec appalachians and st lawrence lowlands the directions of extension compare well with the mean direction of extensional stress inferred from the jurassic dolerite dike trend in new england both extensions are interpreted as the result of rift related stress associated with the separation of north america and africa early in the late triassic early jurassic fragmentation of pangea the paleostress field configuration is assumed to be related to the direction of divergent plate motion the n s and ne sw late proterozoic faults that bordered the quebec reentrant and taconian acadian structures of the quebec appalachians appear to have played a significant role in the dis

textural and compositional controls on modern beach and dune sands new zealand textural compositional physical and geophysical determinations were carried out on 111 beach and dune sand samples from two areas in new zealand the kapiti foxton coast sourced by terranes of andesite and greywackes and the farewell spit wharariki coast sourced by a wide variety of paleozoic terranes our aim is to understand how long shore drift beach width and source rock control the sedimentological and petrographic characteristics of beach and dune sands furthermore this study shows the usefulness of specific minerals quartz plagioclase with magnetite inclusions monomineralic opaque grains to interpret the physical processes fluvial discharges long shore currents winds that distribute beach and dune sands in narrow and wide coastal plains this was done by means of direct grain size and modal analyses and indirect specific gravity magnetic non magnetic separations m nm magnetic susceptibility measurements hysteresis loops methods results are compared with beach sands from hawaii oregon the spanish mediterranean elba island and southern california compositionally the kapiti foxton sands are similar to first order immature sands which retain their fluvial signature this results from the high discharge of rivers and the narrow beaches that control the composition of the kapiti foxton sands the abundance of feldspar with magnetite inclusions controls the specific gravity of the kapiti foxton sands due to their low content of opaque minerals and coarse grain size magnetic susceptibility of the sands is related mainly to the abundance of feldspars with fe oxides volcanic lithics and free opaque minerals the farewell spit wharariki sands are slightly more mature than the kapiti foxton sands the composition of the farewell spit wharariki sands does not reflect accurately their provenance due to the prevalence of long shore drift waves little river input and a wide beach low abundance of feldspar with magnetite inclusions and free opaque grains produces poor correlations between specific gravity sg and fe oxide bearing minerals the small correlation between opaque grains and m nm may be related to grain size the magnetic susceptibility of farewell spit wharariki sands is low due to the low content of grains with magnetite inclusions hysteresis and isothermal remnant magnetization irm agree with the magnetic susceptibility values copyright 2006 john wiley sons ltd

towards a southern european tethyan palaeomargin provenance signature sandstone detrital modes and detrital zircon u pb age distribution of the upper cretaceous paleocene monte bignone sandstones ligurian alps nw italy constraining the source terranes of alpine siliciclastic flysch sequences is crucial for building a clearer picture of the palaeogeography and geodynamic evolution of the western tethys in the framework of impending continental collision this paper presents an integrated study that involves palaeocurrent dispersal analysis sandstone petrography and detrital zircon geochronology of the upper cretaceous paleocene monte bignone sandstones a siliciclastic turbidite system deposited during the pre collisional evolution of the ligurian alps palaeocurrent analysis illustrates an overall eastward transport of the proximal sediments in the present configuration considering the ca 45 50 counter clockwise rotation of the tertiary piedmont basin and of the corsica sardinia block in the late paleogene this indicates the derivation of the sediments from the northern margin of the piedmont ligurian ocean sandstone petrography records a stratigraphic evolution from quartzose sandstones towards lithic and then to lithic sub arkosic composition this trend is interpreted to reflect the gradual unroofing of the provenance terrane the lithotypes of the recycled sedimentary rock fragments and the up section increase in dolostone and carbonate clast proportions suggest the erosion of the sedimentary cover of the southern european palaeo margin new geochronological data u pb detrital zircon ages correspond to the pre alpine stages of crustal growth recorded in the variscan maures tanneron massif and therewith confirm the derivation of the sediments from the passive palaeo european margin this conclusion highlights the importance of the lower plate in providing the source of coarse clastic deep water successions during pre collisional convergent steps results from this multi proxy provenance analysis contribute to better defining the detrital signatures associated to the continental micro fragments that constituted the palaeo european plate as it supplied deep sea siliciclastic sediments into the piedmont ligurian ocean prior to continental collision

reply to comment on alternating contractional and extensional events in the alpujarride nappes of the alboran domain betics gibraltar arc

a source to sink compositional model of a present highstand an example in the low rank tiber depositional sequence latium tyrrhenian margin italy abstract our source to sink compositional model of sediment distribution in the present highstand of the tiber depositional sequence has important implications for sediment source lithology generation transport and deposition in the tiber river system sand compositional trends reflect provenance mixing anthropic intervention and the effects of local autogenic factors in continental to marine depositional environments fluvial feldspatho quartzo lithic sand results from the contribution of the major tributaries of the tiber drainage basin which can be divided into two sub basins separated by the corbara dam built in the 1950s upstream drainage basin sand has a siliciclastic sedimentary lithic signature whereas carbonate and volcanic lithic fragments dominate downstream drainage basin sand downstream sand is further modified in the coastal environment by hydraulic sorting and mixed with detritus derived from the recycling of coastal dune sand and altered volcaniclastic paleosols the latter are associated with lower course floodplain and channel deposits which produce a quartzo feldspatho lithic sand sediment grain size zonation in the marine environment is influenced by coastal hydrodynamics which in turn produce two detrital populations with distinct compositional signatures and hydraulic behavior coarser minerals essentially pyroxene phenocrysts and finer feldspar grains are progressively concentrated in higher energy and lower energy environments respectively biogenic continental shelf and slope deposits off the tiber river mouth show very little riverine influence this study of the last highstand system tract in the tiber depositional sequence clarifies the effects of hydraulic sorting grain size dependence and sediment reworking in controlling the final composition of modern sand this knowledge can be used to better understand detrital modes of ancient sedimentary successions

western mediterranean sand deposits as a raw material for roman glass production abstract during the late roman and byzantine period natron glass was made from its raw materials in a limited number of primary production centres in egypt and syro palestine for the earlier hellenistic and roman period no primary furnaces have been found and the location of primary production during this era remains unclear ancient authors such as strabo and pliny the elder suggest that glassmaking sands were found near the river belus israel in egypt near the mouth of the volturno river italy and also in spain and france however primary production in the western part of the mediterranean is not supported by any direct archaeological evidence and possible sand raw materials from these regions have never been evaluated for their suitability to produce glass in this study 178 modern beach sands from spain france and italy were analysed for their major and minor elemental compositions by calculating the composition of the glasses that can be produced with these sediments after the addition of pure natron and comparison with the composition of typical roman natron glass we were able to judge whether or not these sands are suitable for roman glass production the results indicate that good glassmaking sands are rather rare only a very limited number of the 178 analysed beach sands would produce a glass with major and minor elemental compositions within the ranges of roman imperial natron glass the rest of the analysed sands are unsuitable for glass production in their present form due to their insufficient sio 2 high al 2 o 3 and fe 2 o 3 and either too low or too high cao contents if the sand raw material was too low in cao extra lime could be added to the glass batch in the form of shell or limestone this was taken into account in a second calculation overall we were able to define six limited areas where suitable sand raw materials would have been available to the roman glassmaker good glassmaking sands occur in the basilicata and puglia regions se italy and tuscany w italy after the addition of an extra source of lime also sands from the huelva province sw spain the murcia region se spain and from the provence se france would produce glasses with a typical roman composition

recycled detrital quartz grains are sedimentary rock fragments indicating unconformities examples from the chhattisgarh supergroup bastar craton india abstract recycled detrital quartz grains are unequivocally identified if there are overgrowths on abraded overgrowths we argue that the presence of such recycled grains even in small quantities in successions of quartz arenites indicates derivation from one or more sedimentary units from below an intrabasinal unconformity or an extrabasinal unroofing surface as do detritus from characteristic rock fragments in polymict clastic rocks in fact detrital grains with inherited overgrowths are sedimentary rock fragments we apply this petrographic criterion to evaluate the presumed unconformities that bound the singhora chandarpur raipur and the kharsiya groups of the essentially mesoproterozoic chhattisgarh supergroup in the bastar craton a critical ur craton vis a vis columbia and rodinia optical examination of about 6000 grains in 12 thin sections reveal few recycled quartz grains in sandstone samples of the chandarpur group but about 4 recycled quartz grains with inherited abraded overgrowths in a sandstone unit of the raipur group characteristic rock fragments from a tuffaceous unit at the top of the raipur group are found in the basal sandstone of the kharsyia group the data indicate that the presumed unconformities below the kharsyia group and the raipur group are real but the one above the singhora group cannot be confirmed on the basis of recycled grains published age spectra of detrital zircons from these sandstones are compatible with the above inferences drawn from detrital quartz and rock fragment petrography

global sensitivity analysis for crosswell seismic and neutron capture measurements in co2 storage projects abstractquantification of reservoir uncertainty is an essential part of a monitoring design a systematic approach that quantitatively links predicted uncertainties in a monitoring program to the underlying reservoir variability is however needed we developed a methodology for quantifying uncertainty in crosswell seismic monitoring combined with neutron capture logging and applied global sensitivity analysis gsa to compute and rank contributions of uncertain reservoir parameters to the predicted uncertainty of the measurements the workflow is illustrated by a numerical study using a simplified model of a co2 storage site where crosswell measurements have not actually been taken synthetic seismic responses are computed through the integration of multiphase flow a new thermodynamically consistent fluid substitution model and a fast marching eikonal solver we quantified uncertainty in first arrival times to illustrate the potential utility of crosswell seismic surveys and their limitation consiste

provenance changes for arenaceous formations of the northern apennines italy a complex pattern of provenances is displayed by 15 formations in the northern apennines composed chiefly of turbidites that were deposited during the alpine orogenesis q f l and qp lv ls values can be used to characterize specific source areas that existed in the apennine region from cretaceous through miocene time whereas sandstone mineralogy can be used to infer plate tectonic setting such an approach must make allowances for both the size of the area studied and the tectonic framework that existed prior to sandstone deposition in an early stage of the compressive phase of the tethys late cretaceous both arkose and litharenite were derived from cratonic blocks whereas volcanic sandstone was derived from uplifted oceanic sediments and lavas sediments recording the main oligo miocene collisional tectonic phases accumulated in two principal tectonic settings 1 intermontane successor basins and 2 foreland basins in the first case individual formations exhibit a wide provenance variability arkosic lithic sandstone recycled orogen volcanic sandstone magmatic arc and arkose were deposited simultaneously in the second case basins filled with thick turbidite sequences composed of arkose and lithic arkose which were supplied by basement rocks uplifted along the edge of the european craton and or by the nascent orogenic belt

weathering profiles in granitoid rocks of the sila massif uplands calabria southern italy new insights into their formation processes and rates abstract in this paper we characterized several weathering profiles developed on granitoid rocks in the sila massif upland calabria southern italy integrating detailed macro and micromorphological observations with physico mechanical field tests and petrographic mineralogical and geochemical analyses we focused our attention on the main weathering and pedogenetic processes trying to understand apparent discrepancies between weathering grade classes based on field description and geomechanical properties and two common weathering indices such as the micropetrographic index ip and the chemical index of alteration cia our results showed that sericite on plagioclase and biotite chloritization that represent inherited features formed during late stage hydrothermal alteration of granitoid rocks may cause an overestimation of the real degree of weathering of primary mineral grains under meteoric conditions especially in lower weathering grade classes moreover the frequent identification of fe mn oxides and clay coatings of illuvial origin rather than or in addition to those formed in situ both at the macro and microscale may also explain an overestimation of the weathering degree with respect to field based classifications finally some apparent inconsistencies between field geomechanical responses and chemical weathering were interpreted as related to physical weathering processes cryoclastism and thermoclastism that lead to rock breakdown even when chemical weathering is not well developed hence our study showed that particular caution is needed for evaluating weathering grades because traditional field and geochemical petrographic tools may be biased by inherited hydrothermal alteration physical weathering and illuvial processes on the basis of chronological constraints to soil formation obtained from a 42 ka old volcanic input mixed to granite parent materials detected in the soil cover of the sila massif upland a first attempt to estimate soil formation rates was achieved for different depths of corresponding weathering profile zones soil formation rates ranged from 0 01 0 07 mm a 1 for a and bw horizons weathering class vi to 0 04 0 36 mm a 1 for the underlying saprolite c and cr layers class v by comparing these results with the corresponding erosion rates available in the literature for the study area that range from

the 4d microgravity method for waterflood surveillance part ii gravity measurements for the prudhoe bay reservoir alaska between 1994 and 2002 a series of experiments was conducted at prudhoe bay alaska aimed at the development of an effective 4d or time lapse gravity technique theoretical investigations had pointed out the potential for monitoring water injection in the 2500 m deep reservoir but it was not clear that gravity measurements of sufficient accuracy could be made in the arctic environment during the course of these experiments new techniques and instrumentation were introduced and perfected for both gravity and position measurements gravity stations are located using high precision global positioning system gps techniques without permanent monuments robust methods for meter drift control have improved noise resistance in relative gravimeter surveys absolute gravity measurements with a field portable instrument maintain absolute gravity levels among surveys a 4d gravity difference noise of 12 gal standard deviation has been established at prudhoe bay for gps controlled relative gravimeter surveys

alternating contractional and extensional events in the alpujarride nappes of the alboran domain betics gibraltar arc in the western alpine system neogene extensional tectonics triggered the development of marine basins on the concave side of tight orogenic arcs as happened within the alboran crustal domain the hinterland of the gibraltar arc a detailed analysis of the structural and metamorphic records of one of the main alboran domain complexes however plainly reveals a complex tectonic evolution prior to the development of the miocene arc back arc system which includes a major intraorogenic extensional event this large scale subvertical shortening that can be assessed from the pt paths of representative tectonic units was subsequent to the continental crust subduction inferred from high pressure low temperature mineral asssemblages the crustal section was thinned in nearly isothermal conditions its thickness being reducted to at least 1 3 of the initial value yet still before the miocene a second contractional event led to the overthrusting of high grade metamorphic rocks over other low grade rocks accompanied by subordinate overturning of the metamorphic zones since migration of the gibraltar arc is roughly balanced by crustal spreading in the back arc available data concerning miocene extension suggest that the alboran domain can be restored to its appropriate position several hundred kilometers to the east thus a collision belt that underwent significant intraorogenic extension must have existed in what is now the western south balearic basin

stable isotope evidence for regional scale fluid migration in a barrovian metamorphic terrane vermont usa we measured the c and o isotopic composition of carbonate minerals in the waits river formation eastern vermont to determine the extent of fluid infiltration during regional metamorphism over an approx 2000 km2 area in a deep seated 25 km barrovian terrane from a petrologic study of this terrane ferry proposed the existence of a large regional metamorphic hydrothermal system with two first order features 1 on the scale of the entire terrane fluid flow was focused into the axes of two major antiforms of regional extent 2 on a smaller scale about 100 km2 flow was further focused around synmetamorphic granitic plutons that intruded along the axes of the antiforms we find isotopic evidence for both the regional hydrothermal activity along the antiforms and the more intense fluid flow around synmetamorphic plutons the evidence for hydrothermal activity around the plutons is large heavy isotope depletions up to 6 9 in 18ocarb and 13ccarb in diopside zone rocks adjacent to the plutons these isotopic shifts are greater than can be explained solely by prograde metamorphic reactions we find two lines of evidence for the more diffuse regional flow that was focused into axes of the antiforms first 18ocarb and 13ccarb within individual outcrops become increasingly homogeneous with increasing grade towards antiform axes indicating that the rocks equilibrated with a permeating fluid second there are depletions in 18o near the margins of the waits river formation which can be interpreted as a dispersed advective infiltration front displaced toward the antiform axes these fronts were modelled using eq 13 of bickle and baker and imply time integrated fluid of 105 106 cm3 cm2 which are consistent with values derived by ferry from measured progress of prograde devolatilization reactions

very coarse grained beaches as a response to generalized sea level drops in a complex active tectonic setting pleistocene marine terraces at the cadiz coast sw spain abstract the studied pleistocene deposits at the cadiz coast are located on the current intertidal zone or at cliffs parallel to the actual coast 6 50 m a s l from the localities of el puerto de santa maria to chiclana five sequences of very coarse grained beaches have been recognized and dated they unconformably overlie pliocene units and are formed by clast supported conglomerate and coarse grained sandstone chronological ages 87 sr 86 sr and ams 14 c analysis and stratigraphic correlation stand that the oldest marine terrace is the one placed topographically higher and towards the se of cadiz city dated as early pleistocene 1 3 ma after it the sea retreatment produces subaerial exposure of sequence 1 and the development of several calcrete profiles and a paleokarst subsequent sea level rises allow the sedimentation of sequences 2 3 and 4 during early middle pleistocene 1 to 0 8 ma in areas close to cadiz city with subaerial exposure recorded at the top of sequences 3 and 4 during the very upper pleistocene sedimentation of sequence 5 occurs towards the se of cadiz city based on the spatial position of sequence 5 we can conclude that this area constituted a downthrown block during the latest pleistocene in relation to neotectonic processes and diapirism sandstone framework hybrid arenites reveals that main source areas for these marine terraces include units from the betic orogene betic external zones triassic and jurassic rocks and the gibraltar arc the guadalquivir basin passive margin iberian massif the guadalquivir foreland basin marine miocene and pliocene record and local inputs of pleistocene units the siliciclastic supplies from sources were mainly constant during the sedimentation of all set of sequences suggesting maturation processes as reworking and recycling of homogenized sediments during transport early diagenetic processes have been identified as carbonate cementation neomorphism and dissolution outlining the deduced sea level fluctuations during deposition of pleistocene sequences the marine terraces arrangement and its comparison with regionally adjacent areas allows to deduce that the southern and central portuguese coast iberian massif and of the southern and southeastern spanish coast betic orogene were predominantly tectonically raising during pleistocene however the cadiz gulf coast formerly guadalquivir foreland basin was mainly sinking during the same time interval

gravimetric monitoring of gas reservoir water influx a combined flow and gravity modeling approach knowledge of the magnitude and distribution of water influx can be essential for managing water drive gas fields geophysical fieldwide monitoring can give valuable information particularlyoffshorewherewellcontrolissparseand observationwellsareexpensive advancesintheaccuracyof seafloor time lapse gravimetry have made this method feasible it can quantify which areas are flooded providing information complementary to well monitoring production and 4d seismic data gravimetric monitoring may aid materialbalance calculations which are vital for assessing reservoirdrive mechanism and estimating initial and remaining gas volumes in addition it can constrain reservoir simulation models our goal is to produce better physical insight into typical density changes occurring in water drive gas fields andtheirassociatedsurface gravityresponse itisfeasibleto monitor displacement of gas by water in reservoirs that are only a few meters thick gravimetric monitoring can detect edgewater encroachment in early stages with current accuracy the method is applicable for gas reservoirs of modest size 210 8 m 3 in situ gas volume at medium depths 2k m

detectability of petrophysical properties of subsurface co2 saturated aquifer reservoirs using surface geophysical methods the process of capturing carbon dioxide co2 and injecting it into deep saline aquifers is becoming an important method to reduce future atmospheric emissions of co2 key challenges facing carbon capture and storage ccs are the storage reservoir s size and safety the storage size can be addressed by focusing on large saline aquifer reservoirs the safety concern may be lower if co2 is injected into depleted hydrocarbon reservoirs because their cap rock integrity is already proven but such capping systems are generally potentially compromised by poorly cemented abandoned wells and compared to saline aquifers their storage size is small therefore the long term focus of ccs is on saline aquifers to reduce the corresponding risks comprehensive long term monitoring is inevitable

actualistic ophiolite provenance the cyprus case abstract the island of cyprus represents an excellent site to assess quantitatively petrologic clastic response to actively obducting oceanic sources in order to define an actualistic reference for ophiolite provenance in terms of framework composition and heavy mineral suites an improved methodology an extension of the classic ternary qfl logic to include a wider spectrum of key indexes and ratios provides an accurate synthesis of modal data and allows differentiation of three main petrographic provinces and at least seven subprovinces diagnostic signatures of detritus from various levels of an oceanic lithospheric source and criteria for distinguishing provenance from suprasubduction versus mid oceanic ophiolites are also outlined modern sands derived from the troodos ophiolite contain variable proportions of largely pelagic carbonate to chert boninite to basalt diabase to metabasite plagiogranite to gabbroic and cumulate grains supplied from progressively deeper seated levels of the multilay

reductive deposition of graphite at lithological margins in east central vermont a sr c and o isotope study o sr and c isotopes from east central vermont are used to provide information on the timing and volume of metamorphic fluid flow the results are then used to assess the evidence for redox transformations between c species oxygen profiles are homogenised on a metre scale comparison with sr isotopes suggest that o alteration may have occurred over a significantly larger timescale than that of sr possibly because o was modified during dewatering and diagenesis in addition to the high temperature alteration recorded by strontium sr isotope distributions are consistent with cross layer fluid fluxes of 104 106 moles m 2 absolute values depend on the sr fluid rock distribution coefficient which is poorly known however reaction progress constraints suggest that fluxes were towards the lower end of this range high 13c values observed at lithological boundaries cannot be explained by volume loss or closed system processes and are taken to indicate reductive precipitation of graphite as a result of mixing between co2 and ch4 bearing fluids mass balance calculations indicate that redox reactions occurring under metamorphic conditions convert a minimum of 10 of the co2 released from limestones into graphite thus providing a potentially important control on the average residence time of c within the crust with implications for c cycling models

sedimentology and composition of sands injected during the seismic crisis of may 2012 emilia italy clues for source layer identification and liquefaction regime abstract in may 2012 widespread sand blows formed along buried channels in the eastern sector of the po plain northern italy as a consequence of a series of seismic events with main shocks of mw 6 1 and 5 9 at san carlo ferrara a trench dug a few week after the earthquakes exposed sand dikes cutting through an old reno river channel levee system that was diverted in the 18th century and was deposited starting from the 14th century unit a this sequence overlies a holocene muddy floodplain deposits and contains scattered sandy channel deposits unit b and a pleistocene channel sand unit unit c sands with inverse and normal grading concave layering and vertical lamination coexisting along the dikes suggest multiple rhythmic opening and closing of the fractures that were injected and filled by a slurry of sand during the compression pulses and emptied during the extension phase the pulse mechanism may have lasted for several minutes and formed well stratified sand volcanoes structures that formed at the top of the fractures sands from dikes and from the various units show well defined compositional fields from lithoarenitic to quartz feldspar rich compositions sands from the old reno levee and channel fill unit a have abundant lithic fragments derived from the erosion of apennine sedimentary carbonate and terrigenous successions composition of the sand filling the dikes show clear affinities with sand layers of the old reno river channel unit a and clearly differ from any sand from deeper holocene and pleistocene layers unit b and c which are richer in quartz and feldspar and poorer in sedimentary lithic fragments sorting related to sediment flux variations did not apparently affect the sand composition across the sedimentary structures textural and compositional data indicate that the liquefaction processes originated from a relatively shallow source consisting of channel sands located within unit a at 6 8 to 7 5 m depth

interpreting provenance relations from sandstone detrital modes southern italy foreland region stratigraphic record of the miocene tectonic evolution abstract the southern italy orogen preserves deep marine turbitic clastic wedges that record the key tectonic events during structural growing over the adria margin the regional tectonic transition from thick skinned calabrian accretion and deformation during late paleogene to middle miocene to thin skinned southern apennines thrusting since early middle miocene is recorded by diverse contrasting petrofacies in uppermost paleogene and miocene sandstones of dominantly turbiditie deposits most of these sandstones reflect in time quartzolithic and quartzofeldspathic and arkosic petrofacies derived from growing and unroofing calabrian terranes quartzose petrofacies mainly indicate provenance from cratonal african margin during langhian and or from lowland internal domains before its deformation during the cretaceous to paleogene volcaniclastic sandstone petrofacies also testify active volcanism during the late paleogene to early miocene these variable compositions indicate strong palaeogeographic constraints for the central western mediterranean during the neogene reflecting provenance relationships from differentiate source rocks these include interplays between ophiolitiferous uplifted continental shallow to deep crust terranes volcanic and sedimentary mostly carbonate source rocks sandstone detrital modes provide an example of the close relations between clastic compositions and growing orogen in southern italy and may contribute to unravel the geodynamic history of other major orogens

modern sand from obducted ophiolite belts sultanate of oman and united arab emirates abstract oman and the united arab emirates host the largest ophiolites on earth and are characterized by arid tropical climate and desert conditions they thus provide an unexcelled natural laboratory in which to study sediments derived from allochthonous oceanic lithosphere and to define an actualistic petrogenetic model for obduction orogen provenance spectacularly exposed in se arabia are two distinct obducted ophiolite sequences sama il and masirah that contrast widely in formation setting spreading rate detachment level thermal state during emplacement and relief masirah beach sand chiefly consists of basaltic diabase to metadiabase plagioclase gabbroic and dunite grains from progressively deeper seated levels of the multilayered oceanic crust dense minerals include diopsidic clinopyroxene and hornblende from gabbros epidote and tremolite actinolite from altered dikes and augite from basaltic lavas in contrast sand from the sama il ophiolite includes cellular serpentinite grains and en

application of actualistic models to unravel primary volcanic control on sedimentation taveyanne sandstones oligocene northalpine foreland basin abstract this work is focused on the taveyanne sandstones gres de taveyanne an oligocene volcaniclastic turbidite sequence cropping out in the northern alpine molassa between se france and central switzerland with the aim to investigate the temporal relationship between volcanic activity and sediment supply detailed stratigraphic sedimentological and petrographic xrd analyses on mudstones and point counts on sandstones studies conducted on three sections col de l oulette and flaine in se france taveyanne in sw switzerland allow a discrimination of three main facies among which only one is extremely enriched in volcaniclastic detritus and characterized by features similar to those of disaggregated pyroclastic density current deposits the other two facies are characterized by variable to no volcanic detritus but supplied by crystalline and sedimentary detritus such sediment trends are similar to those of modern volcanically controlled source to sink systems this allows a reinterpretation of the taveyanne sandstones as a syn volcanic turbidite system episodically supplied by large amounts of volcanic detritus which periodically modified the drainage paths moreover the well known temporal and spatial persistence of such modifications in modern settings leads to conciliate the syn volcanic supply with the location of the volcanic centers in the internal part of the alps without invoking particular climatic and tectonic conditions controlling foreland sedimentation