an analytical model of the response of the meridional overturning circulation to changes in wind and buoyancy forcing abstractan analytical model of the full depth ocean stratification and meridional overturning circulation for an idealized atlantic basin with a circumpolar channel is presented the model explicitly describes the ocean response to both southern ocean winds and the global pattern and strength of prescribed surface buoyancy fluxes the construction of three layers defined by the two isopycnals of overturning extrema allows the description of circulation and stratification in both the upper and abyssal ocean the system is fully solved in the adiabatic limit to yield scales for the surface layer thickness buoyancies of each layer and overturning magnitudes the analytical model also allows scaling of the antarctic circumpolar current acc transport the veracity of the three layer framework and derived scales is confirmed by applying the analytical model to an idealized geometry eddy permitting ocean general circulation model consistent with previous results the abyssal overturning is found to scale

the adiabatic pole to pole overturning circulation abstractthe adiabatic pole to pole cell of the residual overturning circulation roc is studied in a two hemisphere semienclosed basin with a zonally reentrant channel occupying the southernmost eighth of the domain three different models of increasing complexity are used a simple analytically tractable zonally averaged model a coarse resolution numerical model with parameterized eddies and an eddy resolving general circulation model two elements are found to be necessary for the existence of an adiabatic pole to pole cell 1 a thermally indirect wind driven overturning circulation in the zonally reentrant channel analogous to the deacon cell in the antarctic circumpolar current acc region and 2 a set of outcropping isopycnals shared between the channel and the semienclosed region of the northern hemisphere these points are supported by several computations varying the domain geometry the surface buoyancy distribution and the wind forcing all three models give results that are qualitat

a recent tectonic reorganization in the south central mediterranean abstract new geodetic data combined with seismicity geologic and geochemical information document a major tectonic reorganization in the central mediterranean around 0 8 0 5 ma when rapid trench migration and consequent tyrrhenian back arc extension which dominated the region s evolution since the tortonian 10 8 ma essentially stopped in response the african convergence in sicily was transferred to a back thrust in the southern tyrrhenian characterized by frequent m5 6 earthquakes in the last 20 years a diffuse transform boundary formed across northeastern sicily to connect the sicilian and calabrian plate boundaries causing opening of the messina straits home to large historical earthquakes and unusual volcanism in the aeolian island arc and the intraplate mount etna a divergence of the ionian region from the main part of africa with northeastward motions that reflect the joint influence of african push and hellenic slab pull and are transmitted to calabria and adria could explain motions observed in the sicily channel calabria and apulia as well as the high level of southeastern sicilian seismic activity

sea level change along the italian coast during the holocene and projections for the future published and new sea level data are used to provide projections of sea level change in italy for the year 2100 by adding new isostatic and tectonic component to the ipcc and rahmstorf projections comparison of the observations from more than 130 sites with different geomorphological and archaeological sea level markers with the predicted sea level curves provides estimates of the vertical tectonic contribution to the relative sea level change the results are based on the most recent anu model for the ice sheets of both hemispheres including an alpine deglaciation model on the basis of the eustatic tectonic and isostatic components to the sea level change projections are provided for marine inundation scenarios for the italian coastal plains for the year 2100 that today are at elevations close to current sea level

on the abruptness of bolling allerod warming abstractprevious observations and simulations suggest that an approximate 3 5 c warming occurred at intermediate depths in the north atlantic over several millennia during heinrich stadial 1 hs1 which induces warm salty water wsw lying beneath surface cold freshwater this arrangement eventually generates ocean convective available potential energy ocape the maximum potential energy releasable by adiabatic vertical parcel rearrangements in an ocean column the authors find that basin scale ocape starts to appear in the north atlantic 67 5 73 5 n and builds up over decades at the end of hs1 with a magnitude of about 0 05 j kg 1 ocape provides a key kinetic energy source for thermobaric cabbeling convection tcc using a high resolution tcc resolved regional model it is found that this decadal scale accumulation of ocape ultimately overshoots its intrinsic threshold and is released abruptly 1 month into kinetic energy of tcc with further intensification from cabbeling tcc has convective

an indicator of the multiple equilibria regime of the atlantic meridional overturning circulation recent model results have suggested that there may be a scalar indicator s monitoring whether the atlantic meridional overturning circulation moc is in a multiple equilibrium regime the quantity s is based on the net freshwater transport by the moc into the atlantic basin it changes sign as soon as the steady atlantic moc enters the multiple equilibrium regime because of an increased freshwater input in the northern north atlantic this paper addresses the issue of why the sign of s is such a good indicator for the multiple equilibrium regime changes in the atlantic freshwater budget over a complete bifurcation diagram and in finite amplitude perturbation experiments are analyzed in a global ocean circulation model the authors show that the net anomalous freshwater transport into or out of the atlantic resulting from the interactions of the velocity perturbations and salinity background field is coupled to the background steady state state freshwater budget and hence to s the sign of s precisely shows whether this net anomalous freshwater transport is stabilizing or destabilizing the moc therefore it can indicate whether the moc is in a single or multiple equilibrium regime

a revision of the 1693 eastern sicily earthquake and tsunami the 1693 earthquake was a disastrous event affecting eastern sicily southern italy where it caused over 60 000 victims and total destruction of several villages and towns in the districts of siracusa ragusa and catania the earthquake was followed by a tsunami that struck the ionian coasts of sicily and the messina strait and was probably observed even in the aeolian islands historical documents on sea waves and flooding though not abundant allow us to form a picture of the tsunami first attack and inundation the first water movement all along the sicilian coastline was a strong sea withdrawal followed by a violent sea return and coastal flooding the main purpose of this research is to put constraints on the focal mechanism of this earthquake on the basis of the available documents on the tsunami 1 by simulating tsunami from different possible sources via numerical modeling based on finite element technique and shallow water approximation and 2 by choosing the source best fitting the tsunami data as the most plausible cause for this tsunami the relevance of this study should also be evaluated in light of the circumstance that no certain indication on the earthquake fault can be deduced from the available macroseismic data alone solving the source problem for this event one of the largest occurring in southeastern sicily in historical times is a significant contribution to understanding the seismotectonic regime of the region and to assessing the related earthquake and tsunami hazard risk with implications on mitigation policies

late quaternary slip rates on the acireale piedimonte normal faults and tectonic origin of mt etna sicily abstract mt etna is located along the east coast of sicily near the boundary between the continental crust of the hyblean plateau and the mesozoic oceanic crust of the ionian basin the main active faults near mt etna cut the base of its eastern flank forming a 30 km long system of nne and nnw trending ene chelon fault segments the acireale piedimonte system showing dip slip and oblique right lateral motion most segments are associated with shallow depth seismicity and all have late pleistocene to holocene vertical slip rates ranging between 1 and 2 mm yr typical of major active normal faults worldwide eruptive fissures arranged in nne to ne trending zones cut the highest slopes of the volcano on the footwall of the normal fault system structural analysis suggests that current motions along both the active faults and eruptive fissures are kinematically compatible and simply linked with ongoing wnw ese directed regional extension such extension characterizes at a greater scale the active tectonics of southern italy where all large shallow historical earthquakes have remained confined within a narrow normal fault belt or rift zone stretching from the northern calabrian arc to southeastern sicily the southernmost west dipping faults of that rift zone in calabria aspromonte cut across the calabro peloritan thrust belt to join the mostly east dipping acireale piedimonte faults along the western boundary of ionian oceanic lithosphere which continues southwards as the malta escarpment we thus relate magmatism at etna to dilational strain on the footwall of an east facing crustal scale normal fault at the bend where the siculo calabrian rift zone veers 60 eastwards as it begins to cross the calabrian arc leaving the east facing margin of the ionian sea to catch up with the west facing margin of the tyrrhenian sea farther north

decadal response of global circulation to southern ocean zonal wind stress perturbation abstract a substantial component of north atlantic deep water formation may be driven by westerly wind stress over the southern ocean variability of this wind stress on decadal time scales may lead to circulation variability far from the forcing region the hybrid coordinate ocean model hycom a numerical ocean model is used to investigate the spatial patterns and the time scales associated with such wind variability the evolution of circulation and density anomalies is observed by comparing one 80 yr simulation forced in part by relatively strong southern hemisphere westerlies with a simulation driven by climatological wind the volume transport anomaly takes about 10 yr to reach near full strength in the entire southern hemisphere however in the northern hemisphere it grows for the duration of the run the southern hemisphere indo pacific volume transport anomaly is about twice the strength of that found in the atlantic in the thermocline water exits the southern westerlies belt in a broad f

estimating lorenz s reference state in an ocean with a nonlinear equation of state for seawater thestudyofthemechanicalenergybudgetoftheoceansusingthelorenzavailablepotentialenergy ape theoryisbasedonknowledgeof theadiabaticallyrearrangedlorenzreferencestateofminimumpotentialenergy thecompressibleandnonlinearcharacteroftheequationof state for seawater has been thought to cause the reference state to be ill defined casting doubt on the usefulness of ape theory for investigating ocean energetics under realistic conditions using a method based on the volume frequency distribution of parcels as a function of temperature and salinity in the context of the seawater boussinesq approximation which is illustrated using climatological data the authors show that compressibility effects are in fact minor the reference state can be regarded as a well defined one dimensional function of depth whichformsasurfaceintemperature salinity anddensityspacebetweenthesurfaceandthebottomoftheocean foraverysmallproportion of water masses this surface can be multivalued and water parcels can have up to two statically stable levels in the reference density profile of which the shallowest is energetically more accessible classifying parcels from the surface to the bottom gives a different reference density profile than classifying in the opposite direction however this difference is negligible this study shows that the reference state obtained by standard sorting methods is equivalent to though computationally more expensive than the volume frequency distribution approach the approachthatispresentedcanbeappliedsystematicallyandinacomputationallyefficientmannertoinvestigatetheapebudgetoftheocean circulation using models or climatological data

early cretaceous rifts of western and central africa an overview abstract the structure and evolution of early cretaceous rift basins in western and central africa are described two stages of rift development and fracturing have been identified 1 from neocomian to early aptian roughly e w and nw trending troughs upper benue n cameroon s chad sudan etc opened in response to a submeridian extensional regime in central africa while in western africa the n s trending transsaharian fault zone acted as a sinistral wrench 2 from middle aptian to late albian large northwest trending troughs e niger sudan sirte etc opened in response to a northeast extensional regime while the central african fault zone from benue to sudan exhibited strike slip movements generating pull apart basins these rift and fracture systems delimit three large blocks within the african plate a western block an arabian nubian block and an austral block the arabian nubian block tends to separate from the two other blocks migrating towards the north during the first stage of basin development and then towards the ne during the second stage the opening of the atlantic ocean was the dominant driving force for the western and austral blocks while the arabian nubian block probably moved in response to the opening of the indian ocean and to the evolution of the tethyan margin

petrophysical and microfacies analysis as a tool for reservoir rock typing and modeling rudeis formation off shore october oil field sinai abstract petrographically the lower miocene rudeis reservoir rock samples in october oil field can be summed up into three reservoir rock types rrts the rrt1 samples are mostly calcareous to ferruginated sandstones sometimes are fossiliferous whereas the rrt2 and rrt3 samples are carbonate rocks of grainstone and packstone microfacies respectively cementation by sparite and compaction are the most important porosity reducing diagenetic factors whereas dissolution and leaching out as well as fracturing are the most dominant porosity enhancing factors the petrophysical and reservoir quality studies include measuring density porosity permeability measurements as well as reservoir quality index rqi flow zone indicator fzi and reservoir potential index rpi calculations the permeability porosity plot is the key factor for discriminating the petrophysical behaviour into these three rock reservoir types petrophysically the studied sandstone rrt1 samples have the best storage capacity and reservoir quality the rqi fzi and the rpi indicate poor to very good reservoir quality whereas the rrt3 samples have the least prospective properties the rqi fzi and the rpi indicates impervious reservoir quality based on the fzi values the studied rudeis formation was discriminated into a number of hydraulic flow units 6 hfus hfu 5 6 are the best reservoir zones they are assigned in the central parts of the studied area whereas the least quality hfu 1 3 was assigned to the south in addition the mercury injection capillary pressure tests micp indicates that the rrt1 samples are ranked as iv fair to vi impervious ranks the rrt2 as v poor to vi whereas the rrt3 samples are impervious samples wettability of the studied rrt1 samples is mostly neutral

long term behaviour of the late quaternary normal faults in the straits of messina area calabrian arc structural and morphological constraints abstract the calabrian arc is located in the peri tyrrhenian orogenic belt of southern italy and is characterised by intense post collision dynamics this consists of rapid regional uplifting combined with active normal faulting affecting the tyrrhenian side of calabria and the ionian coast of sicily the siculo calabrian rift zone the effects of the two combined processes are well exposed in the straits of messina area that represent a major transfer zone located between two opposing sets of normal faults characterising the southern calabria and the northeastern sicily branches of the rift in the straits of messina region the distribution and elevation of the upper quaternary marine terraces suggest a southward propagation of the normal fault belt from calabria to sicily it occurred at about 125 ka after a long period of tectonic quiescence and was triggered by huge elastic releases in southern calabria the long term behaviour recorded on the distinct fault segments of the rift is to relate to the presence of a crustal barrier that influenced both the geometry and the fault propagation along the rift zone

eddy saturation of equilibrated circumpolar currents abstractthis study uses a sector configuration of an ocean general circulation model to examine the sensitivity of circumpolar transport and meridional overturning to changes in southern ocean wind stress and global diapycnal mixing at eddy permitting and finer resolution the sensitivity of circumpolar transport to forcing magnitude is drastically reduced at sufficiently high resolution there is little or no sensitivity of circumpolar transport to wind stress even in the limit of no wind in contrast the meridional overturning circulation continues to vary with southern ocean wind stress but with reduced sensitivity in the limit of high wind stress both the circumpolar transport and meridional overturning continue to vary with diapycnal diffusivity at all model resolutions the circumpolar transport becomes less sensitive to changes in diapycnal diffusivity at higher resolution although sensitivity always remains in contrast the overturning circulation is more sensitive to change in diapycnal

fault pattern and seismotectonic potential at the south western edge of the ionian subduction system southern italy new field and geophysical constraints abstract the south western edge of the calabrian arc in southern italy has been investigated throughout a joint analysis of field marine and geophysical data which provided constraints on the fault pattern and on the seismotectonic potential the study was focused on a poorly known sector of a larger belt of seismically active faults slicing across the ne corner of sicily the so called tindari fault system our data pointed out that the investigated area including the mainland and the ionian offshore is deformed by oblique faulting with a general nw se tectonic trend earthquake distribution and seismic profiles pointed out active deformation in the offshore while the mainland is characterized by the occurrence of a nw se oriented 20 km long structural belt however scarce seismicity has been recorded in the last 30 years alongside this tectonic structure accounting for a possible silent segment of the larger fault system tomographic images revealed that the moho discontinuity is deformed by a ne dipping lithospheric tectonic structure which has been here retained the main mode of deformation and responsible for coseismic displacement in the area as a whole field and geophysical data agree with a general nw se trend segmented pattern of recent active faults that have the potentiality of generating magnitude 6 5 7 earthquakes

pattern and rate of post 20 ka vertical tectonic motion around the capo vaticano promontory w calabria italy based on offshore geomorphological indicators abstract the magnitude and rate of late pleistocene holocene vertical tectonic movements offshore of the capo vaticano promontory western calabria southern italy have been measured on the basis of the present day depth variations of the edges of submerged depositional terraces and associated abrasion platforms that formed below the storm wave base during the sea level stillstand of the last glacial maximum lgm these depositional features represented by submerged prograding wedges and an associated terrace shaped upper boundary have been identified in high resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory and are referred to in this study as lowstand infralittoral prograding wedges lipws our new data and methods provide evidence that lipws can be used as geomorphological indicators of vertical movements in offshore settings with well controlled uncertainty removal of the non tectonic component of vertical changes using an ice volume equivalent eustatic sea level compilation indicates 11 3 2 m of uplift and 25 3 2 m of subsidence from southwest to northeast along the promontory over a distance of 22 km during the post lgm the resulting uplift and subsidence rates including both regional and local components for the last 20 350 1 35 years are 0 54 0 2 mm y and 1 23 0 25 mm y respectively these results are consistent with longer term estimates based on uplifted 215 82 ka old coastal terraces and late holocene shorelines this integration of offshore and coastal markers indicates a pattern of vertical movements characterized by a marked asymmetry associated with a northeast down tilt of the capo vaticano promontory the calculated tilt rate increases by one order of magnitude during the post lgm in respect to the time interval from 215 to 82 bp displacement associated with the nw se striking normal fault that bound the capo vaticano promontory to the gioia tauro basin ended in the pleistocene and thus does not contribute to the tilt of the promontory at least during the last 215 ka

the use of scenarios to evaluate the tsunami impact in southern italy this paper outlines the main contributions to the definition and evaluation of tsunami hazard and risk resulting from studies undertaken in italy in recent years and emphasises that adopting characteristic cases or scenarios is a very useful and advantageous technique three main cases are given as valuable examples that is the 1627 gargano tsunami the 1693 eastern sicily tsunami and the 1908 messina straits tsunami since 1 they characterise three distinct tsunamigenic regions 2 they are instances of destructive events and 3 they have been extensively studied in the last decade the paper elucidates the state of the art of the research on these events clarifies the chief points of agreement and disagreement among scientists and illustrates the main issues that are to be addressed by future research to provide reliable assessment of tsunami risk and to implement efficient countermeasures to defend the life of people coastal structures and the coastal environment against the attacks of tsunamis

the role of vertical eddy flux in southern ocean heat uptake 1 the role of changing vertical eddy heat flux on southern ocean heat uptake is investigated in an idealized eddy permitting ocean model enhanced air sea heat flux drives deep reaching southern warming due to a reduction in the isopycnal meridional temperature gradient and therefore decreased upward eddy heat flux this mechanism is qualitatively similar in models with either permitted or parameterized eddies due to its dependence on the isopycnal temperature gradient rather than the dynamical response of the eddy field in contrast increased wind stress drives mid depth southern ocean cooling through an enhancement of the eddy field and resultant eddy heat divergence the transient cooling extends over multiple decades while the mean flow adjusts to balance the faster eddy response this wind driven cooling mechanism has not been captured by coarse resolution models with fixed eddy parameterizations and is a possible candidate for the recent cooling observed in the southern ocean

integrated geological and petrophysical characterization of oligocene deep marine unconventional poor to tight sandstone gas reservoir abstract the present study aims to evaluate discriminate and delineate the geological and petrophysical situation of oligocene reservoir wells at salamat 1 and atoll 1 in north damietta offshore concession in the mediterranean sea it deals with a combined interpretation of the core analysis density porosity permeability and mercury injection capillary pressure micp and petrography data thin sections scanning electron microscope and x ray diffraction as well as well log gamma ray density neutron micro spherical logs msfl shallow and deep resistivity and modular formation dynamic tester logs and the subsurface geologic data as well as some available seismic sections to clarify the geological and the petrophysical characterization of the oligocene unconventional tight sandstone gas reservoir salamat structure north damietta offshore mediterranean sea egypt petrophysically the studied sandstone core samples can be summed up into two reservoir rock types rrt where poor reservoir quality is assigned to one group while the other is characterized by tight reservoir properties these two rrts are discriminated into four microfacies two arenite groups and two wacke groups filling the pore spaces with detrital clays are the most important reservoir quality reducing factors the seismic data indicates that the studied area is composed of rupelian chattian multi channel system located off shore with many sand channels distributed in the area the lower and upper chattian sand channels comprise the most important reservoir bodies in atoll 1 well to the northeast of the study are gas bearing bodies whereas the rupelian sand channels to the northwest at salamat 1 well are the most important gas bearing channels integration between the available core and well log data indicated that the best storage and flow capacity are assigned to the other water bearing sand channels rather the gas bearing channels in both salamat 1 and atoll 1 wells

multiproxy assessment of holocene relative sea level changes in the western mediterranean sea level variability and improvements in the definition of the isostatic signal abstract a review of 917 relative sea level rsl data points has resulted in the first quality controlled database constraining the holocene sea level histories of the western mediterranean sea spain france italy slovenia croatia malta and tunisia we reviewed and standardized the geological rsl data points using a new multi proxy methodology based on 1 modern taxa assemblages in mediterranean lagoons and marshes 2 beachrock characteristics cement fabric and chemistry sedimentary structures and 3 the modern distribution of mediterranean fixed biological indicators these rsl data points were coupled with the large number of archaeological rsl indicators available for the western mediterranean we assessed the spatial variability of rsl histories for 22 regions and compared these with the ice 5g vm2 gia model in the western mediterranean rsl rose continuously for the whole holocene with a sudden slowdown at 7 5 ka bp and a further deceleration during the last 4 0 ka bp after which time observed rsl changes are mainly related to variability in isostatic adjustment the sole exception is southern tunisia where data show evidence of a mid holocene high stand compatible with the isostatic impacts of the melting history of the remote antarctic ice sheet our results indicate that late holocene sea level rise was significantly slower than the current one first estimates of gia contribution indicate that at least in the northwestern sector it accounts at least for the 25 30 of the ongoing sea level rise recorded by mediterranean tidal gauges such contribution is less constrained at lower latitudes due to the lower quality of the late holocene index points future applications of spatio temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of mediterranean sea level rise

response of southern ocean convection and abyssal overturning to surface buoyancy perturbations abstractthis study explores how buoyancy driven modulations in the abyssal overturning circulation affect southern ocean temperature and salinity in an eddy permitting ocean model consistent with previous studies the modeled surface ocean south of 50 s cools and freshens in response to enhanced surface freshwater fluxes paradoxically upper ocean cooling also occurs for small increases in the surface relaxation temperature in both cases the surface cooling and freshening trends are linked to reduced convection and a slowing of the abyssal overturning circulation with associated changes in oceanic transport of heat and salt for small perturbations convective shutdown does not begin immediately but instead develops via a slow feedback between the weakened overturning circulation and buoyancy anomalies two distinct phases of surface cooling are found an initial smaller trend associated with the advective overturning adjustment of up to 60 yr followed by more rapid surface cooling during the co

sedimentary and tectonic evolution of the eastern hyblean plateau southeastern sicily during late cretaceous to quaternary time abstract two palaeogeographic domains have been distinguished in the cretaceous quaternary sequences which crop out in the hyblean region of southeastern sicily in the northeast shallow water algal bryozoan calcarenites of oligocene miocene age overlie either cretaceous rudist limestones or volcanics further to the northeast the stratigraphic gap increases as the miocene limestone thins and in the a g i p well catania 10 plio pleistocene sediments and volcanics directly overlie upper jurassic rocks in the southwestern part of the hyblean plateau pelagic sediments occupy the cretaceous miocene interval they were deposited in a shallow basin dipping gently towards the southwest the transition between the two zones is marked by much evidence of synsedimentary tectonic activity such as widespread slumping and the development of megabreccias composed of cretaceous and eocene blocks the palaeogeographic picture is one of carbonate reefs and volcanic seamounts developing in the upper cretaceous they formed platforms fault bounded to the west and southwest from which were derived the detrital sediments found in the basin and occasional spectacular gravity slides in present day terms the structural high probably corresponds to the northeastern margin of the hyblean plateau and in part to the siracusa syracuse malta escarpment the pattern is little changed in the upper miocene with volcanoclastics of phreatomagmatic origin intercalated with coral bioherms overlying algal bryozoan calcarenites upper tortonian lower messinian limestones with a restricted fauna indicate a shallow water environment which grades up into continental conditions in the eastern hyblean plateau the tertiary sequence is capped by pliocene submarine to subaerial mafic lava flows lower pleistocene sediments consist of biocalcarenites and clays which fill deep graben delimited by plio pleistocene faults the inshore continuation of the malta syracuse escarpment system of faults from a tectonic standpoint the hyblean region a gently deformed segment of the african continental margin acted as a foreland during tertiary times a cretaceous eocene tectonic phase was responsible for the palaeogeographic pattern which existed during most of the cenozoic the present pattern is the result of three main tectonic phases following the regional upper miocene uplift of early middle pliocene plio pleistocene and middle pleistocene recent age which influenced the tectonic evolution of the present ionian coast and the malta syracuse escarpment

regional deformation and offshore crustal local faulting as combined processes to explain uplift through time constrained by investigating differentially uplifted late quaternary palaeoshorelines the foreland hyblean plateau se sicily

a 125 kyr long geological record of seismic source repeatability the messina straits southern italy and the 1908 earthquake ms7 2 the occurrence of characteristic earthquakes along segments of major active belts has been described as early as the beginning of the century the large 1908 messina straits blind normal faulting earthquake provides an opportunity to investigate the repetition of characteristic earthquakes and the persistency of the main features of the fault zone over a time scale in the order of 100 kyr we have compared seismological and geodetic descriptions of the 1908 rupture process with long term crustal deformation recorded at different stratigraphic levels by marine terraces marine sedimentary units and landscape features the wealth of elevated coastal features in and around a region affected by large normal faulting earthquakes indicates that coseismic strain is superimposed on much faster uplift on a regional scale we investigated in detail the pattern of deformation of the 125 kyr old lowest emergent terrace and found that it mimics the pattern of elevation changes observed following the earthquake this suggests 1 that the 1908 earthquake is characteristic 2 that its segment boundaries have been stationary during the past 125 kyr and 3 that even the locations of the regions of largest coseismic release do not change through many seismic cycles based on a comparison between observed heights of the 125 kyr terrace and 1908 displacements we estimated an average repeat time of 1000 yr for a 1908 type earthquake we also investigated the height position age and state of deformation of older terraces and found 1 that uplift of the region started about 1 ma and has since continued rather uniformly at 0 9 1 4 mm yr 1 2 that during this time the straits have narrowed at a rate of 10 20 mm yr 1 and 3 that all the main geomorphic features of the messina straits result from the interaction of fast regional uplift 1908 type coseismic subsidence and global sea level fluctuations

comparison of fractal models using nmr and ct analysis in low permeability sandstones abstract fractal geometry provides an effective method for characterization of the complex and irregular pore structure of eocene shahejie low permeability sandstones in the raoyang sag the bohai bay basin china laboratory measurements including porosity permeability scanning electron microscope sem thin sections nuclear magnetic resonance measurements nmr and x ray computed tomography ct technology are used to provide insights into the fractal characteristics of pore structure in sandstones of eocene shahejie formation in the bohai bay basin china quantitative ct analysis reveals the pore radius is not always linear to t2 transverse relaxation time value obtained from the nmr tests but instead power function of t2 fractal analysis was performed on the t2 distribution using various fractal models and the related fractal dimensions are calculated the fractal dimensions calculated using various fractal models are correlated with nmr parameters and permeability the fractal curves break into two segments at the t2cutoff t2 separating the immovable and movable fluids value or smaller when using fractal model and fractal model and only the large scale pore networks can be described by the fractal geometry mostly the entire pore size distributions micro pores to large scale pore networks can be described by the fractal model and the calculated fractal dimensions are in accordance with the ct scanning and thin section data and are strongly correlated with the t2gm geometric mean of t2 permeability and bvi bulk volume of immovable fluids the fractal behaviors of pore size distributions from nmr analysis have implications for pore structure evaluation in low permeability sandstones with similar geological settings

determination of electrofacies using wireline logs based on multivariate statistical analysis for the kareem formation gulf of suez egypt beyond the traditional use of well logs electrofacies were introduced to define a set of log responses that can be used to characterize a bed and permitted it to be distinguished from the other rock units classification of a formation into electrofacies can be used in reservoir characterization and discrimination due to the hydrocarbon potential of the kareem formation we used the conventional well logs of four boreholes and a traditional core analyses data from one of these wells to identify electrofacies of the kareem formation in the southern gulf of suez multivariate statistical analyses such as principal component analysis pca and cluster analysis were used for this purpose the multivariate statistical analyses were applied to the raw log data the normalized data and the standardized log data three pc components were obtained from the analyses and six distinctive electrofacies were extracted from the dendrogram plot these electrofacies showed good correlation with the lithofacies that were described from core analysis in addition applying the reservoir zonation of the studied formation using the stratigraphic modified lorenz sml plot and the sum of squared errors sse methods led to its discrimination into four hydraulic flow units the deduced flow units were validated against the available core data

the energetics of southern ocean upwelling abstractthe ocean s meridional overturning circulation is closed by the upwelling of dense carbon rich waters to the surface of the southern ocean it has been proposed that upwelling in this region is driven by strong westerly winds implying that the intensification of southern ocean winds in recent decades may have enhanced the rate of upwelling potentially affecting the global overturning circulation however there is no consensus on the sensitivity of upwelling to winds or on the nature of the connection between southern ocean processes and the global overturning circulation in this study the sensitivity of the overturning circulation to changes in southern ocean westerly wind stress is investigated using an eddy permitting ocean sea ice model in addition to a suite of standard circulation metrics an energy analysis is used to aid dynamical interpretation of the model response increased southern ocean wind stress enhances the upper cell of the overturning circulation through creation of avail

a proposal for the kinematic modelling of w dipping subductions possible applications to the tyrrhenian apennines system in w dipping subduction zones there is a general eastward progression of the back arc basin accretionary wedge foredeep complex with the forward progression early stages of the complex are revealed by slices of upper crust and sedimentary cover abandoned to the west left floating above a new section of mantle a major shear zone should form at the new moho separating upper crust slices of earlier accretionary stages and the eastward flowing mantle the mantle wedging at the top of the subduction plane could be responsible for the uplift of the central parts of the belt the retreating of the subduction hinge is interpreted as due to the push generated by the eastward mantle flow detected in the hot spot reference frame the foredeep depth is mainly a function of the radius of curvature of the subduction hinge the frontal wedge is constructed from the stacking of the upper layers of the subducting plate and the syntectonic clastics that fill the foredeep which are progressively involved in thrusting and later by extension in order to preserve volume balance the lithosphere of the eastern plate before subduction has to be the same size as that which has been subducted due to the longer length of the arc with respect to the original length of the linear margin between the two converging plates laterally stretched subducted lithosphere is predicted at depth w dipping subductions usually have a short life probably due to their inherent capability to produce new lateral heterogeneities of the lithosphere the thin back arc which are a key factor in controlling and generating new subductions both e and w dipping this model is applied to the apennines tyrrhenian sea system

the transient response of the southern ocean pycnocline to changing atmospheric winds 1 the vertical density structure of the southern ocean is dynamically linked to wind stress at the surface but the nature of this coupling is not fully understood observations from the last several decades show a significant increase in the strength of westerly winds over the southern ocean but an appreciable change in the tilt of constant density surfaces isopycnals has not yet been detected there using a combination of theory and idealized numerical simulations we show that the response of the density structure occurs on centennial timescales making it difficult to detect significant changes with a few decades of hydrographic observations dynamic coupling between the circumpolar current and northern basins regulates the slow adjustment of the density structure our results provide a new interpretation for recent observations and highlight the importance of the interaction between regional southern ocean dynamics and global ocean circulation citation jones d c t ito andn s lovenduski 2011 thetransientresponseofthe southern ocean pycnocline to changing atmospheric winds geophys res lett 38 l15604 doi 10 1029 2011gl048145

does net e p set a preference for north atlantic sinking abstractthe present day global meridional overturning circulation moc with formation of north atlantic deep water nadw and the absence of a deep water formation in the north pacific is often considered to be caused by the fact that the north pacific basin is a net precipitative while the north atlantic is a net evaporative basin in this paper the authors study the effect of asymmetries in continent geometry and freshwater fluxes on the moc both in an idealized two dimensional model and in a global ocean model this study approaches the problem from a multiple equilibria perspective where asymmetries in external factors constrain the existence of steady moc patterns both this multiple equilibria perspective and the fact that a realistic global geometry is used add new aspects to the problem in the global model it is shown that the atlantic forced by net precipitation can have a meridional overturning circulation with northern sinking and a sea surface salinity that resembles the present day sali

borehole image analysis of the nankai accretionary wedge odp leg 196 structural and stress studies electrical images recorded with resistivity at bit rab from two sites drilled during ocean drilling program odp leg 196 were analyzed to study the effects of subduction at the nankai margin for the first time in the history of scientific deep sea drilling in odp in situ complete borehole images of the decollement zone were obtained analyses of all drilling induced fracture data indicated that the maximum horizontal compressive stress shmax axes have an azimuth of 303 and analyses of breakout data from rab images indicated an azimuth of 310 these azimuths approximate the convergence direction of the philippine sea plate towards the eurasian plate the frontal thrust at site 808 was encountered at about 389 mbsf density porosity resistivity and gamma ray data change across the frontal thrust the decollement zone at the deformation front was identified between 937 and 965 mbsf the base of the decollement is sharply defined as the maximum extent of conductive fracturing and is marked by abrupt changes in physical properties mikada h becker k moore j c klaus a austin g l bangs n l bourlange s broilliard j bruckmann w corn e r davis e e flemings p b goldberg d b gulick s s hansen m b hayward n hills d j hunze s ienaga m ishiguro h kinoshita m macdonald r d mcneill l obana s hong o s peacock s pettigrew t l saito s sawa t thaiprasert n tobin h j tsurumi h 2002 proc odp initial rep 196 college station tx ocean drilling program the upper boundary of the decollement is marked by several sets of conductive fractures and by high variability in physical properties the decollement zone is characterized by intense brittle fracturing these fractures are considered to be the consequence of cyclic stresses and high fluid pressures in this zone we analyzed fracture dips and their orientations at both sites and found that they are all consistent with a unique stress field model surrounding the two sites

fault activity and marine terracing in the capo vaticano area southern calabria during the middle late quaternary abstract the capo vaticano peninsula is a structural high bordered by several normal fault segments mainly striking ne sw and wnw ese and belonging to the so called siculo calabrian rift zone both the two fault systems extend in the tyrrhenian offshore and show recent activity in the capo vaticano peninsula six orders of marine terraces with their preserved paleoshorelines and a top surface have been recognised they form a continuous set of morphological elements ascribed to the last seven principal high stands of the eustatic curve occurred from 330 to 60 kyr on the basis of new chronological data available in the recent literature the morphotectonic analysis of the paleoshorelines allowed recognition of a deformation pattern characterised by a northeastward tilting of the area and to quantify the uplift rates moreover vertical slip rates ranging between 0 25 and 2 5 mm yr have been calculated for a wnw ese trending fault segment the coccorino fault in this structural framework the late quaternary uplift of the capo vaticano peninsula can be related to the activity of both the ne sw and wnw ese striking normal fault systems added to the regional component of uplift the recent activity of these structures is also suggested by the 1905 seismic event that occurred offshore of the capo vaticano peninsula

roots of etna volcano in faults of great earthquakes abstract results from several seismic methods allow us to sketch the deep structure of etna and its ionian margin under etna a volume of high velocity material is found in a structurally high position the emplacement of this suggests spreading of the surrounding medium just offshore down to the east normal faults penetrate through the upper crust the deeper crustal structure beneath appears upwarped from the basin towards etna juxtaposed with the crust of sicily a thinner crust reaches from the ionian basin under etna and the mantle is upwarped in such a structure magma can then be viewed as a melted lens capping a mantle upwarp at shallow depth rather than in an intracrustal chamber this reduces the conflict between estimates of its volume from excess output of volatiles and short residence times a link in time is indicated between volcanic and seismic activity at a large scale over the millennium the reported ends of episodes of high output rates of magma are followed by the reported occurrences of magnitude 7 earthquakes which caused destruction in southeastern sicily several steep active normal fault have been imaged to a depth of 10 km the crust up to 30 km offshore of the cities of catania and augusta which may be fault planes for such large earthquakes they expand and prolongate the system of the timpe faults on the eastern flank of etna thus linking large scale tectonics offshore with the volcano etna developed together with normal faulting upwarp and spreading during the recent evolution of the former ionian subduction activation of the material at depth at the lateral edge of the slab by vertical motion with extension above could produce the peculiar type of etna magmatism

the contribution of tectonics to relative sea level change during the holocene in coastal south eastern sicily new data from boreholes abstract in order to detect ongoing vertical crustal movement and assess both tectonic instability and marine invasion risk in the south eastern sicily coastal area holocene sea level indicators have been compared to the sea level curve for the same period a stratigraphical and sedimentological study accompanied by 14 c ams dating has been carried out using seven boreholes in the most depressed coastal sectors the catania plain the lagoonal environments between augusta and siracusa and the vendicari lagoon south of siracusa the distinct boreholes showed irregular transitional successions represented by infralittoral beach sands lagoon and brackish marsh deposits moreover 14 c ams dating on gastropod and bivalves collected at various depths indicated a holocene age for these deposits that lie directly on the lower middle pleistocene substratum taking into account that the infralittoral and lagoon sediments occurring in the analysed coastal areas were deposited during the holocene sea level rise and that the gastropod and bivalve fragments sampled in the boreholes are with good approximation sea level indicators the short term vertical motion undergone by this region during the holocene can be estimated comparing the sampling depth below the present sea level of the dated shells to the sea level rising curve for the central eastern sicily coast the coastal plains between catania and siracusa resulted involved during the holocene in tectonic uplifting with rates varying from about 1 mm y in the catania area to 0 5 mm y in the siracusa area conversely in the same period the south eastern most coastal sector of sicily can be considered tectonically stable these results are comparable to uplift rates obtained from geomorphologic and archaeological sea level markers and are consistent with a remote effect of the active normal fault system located in the ionian offshore between catania and siracusa

the diagenetic destruction of porosity in plutoniclastic petrofacies the miocene diligencia and eocene maniobra formations orocopia mountains southern california usa

mesozoic and cenozoic rocks from malta escarpment central mediterranean sedimentary rocks of triassic neogene age are present on the malta escarpment of the eastern mediterranean upper triassic dolomitic limestones of shallow water origin at depths between 2 5 and 3 5 km are similar in lithofacies to coeval platform carbonates of the siracusa syracuse belt of southern sicily jurassic rocks include lower middle liassic shallow water limestones followed by condensed hemipelagic lime deposits indicative of sinking and starving of the former platform cretaceous materials are represented by both red marls rich in planktonic faunas and reworked volcaniclastic breccias including shallow water skeletal material paleogene rocks are both shallow water limestones with corals algae and bivalves and redeposited calcarenites of lithofacies similar to those from surface and subsurface of the ragusa zone oligocene lower miocene rocks from the escarpment are also similar in lithology to the coeval ragusa deposits tortonian is represented by hemipelagic marls indicating open marine environment pervasive dolomitization on lime crusts and on initial stage fissure fillings with strongly positive isotopic oxygen ratio is thought to be a product of messinian evaporitic drawdown pliocene sediments belong to the trubi facies and consist of pelagic foraminiferal chalk an impressive vertical relief existed by miocene times as attested by messinian crusts and veins on or in rocks as old as late triassic our data do not provide evidence that this morphologic feature necessarily coincides with a continent ocean transition the present escarpment was produced by faulting erosion and defacement

malta escarpment fault zone offshore eastern sicily pliocene quaternary tectonic evolution based on new multichannel seismic data 1 the malta escarpment represents the dominant morphological feature offshore eastern sicily linking the deep ionian basin to the east with the hyblean carbonate platform to the west interpretation of purposely acquired multichannel seismic data allows division of the malta escarpment into two portions characterized by different tectonic structures along the segment south of siracusa the malta escarpment is not affected by recent faulting and appears as a steep surface that flattens out toward the ionian basin a recent deformation characterized by a broad area of uplift occurs 20 30 km east from the slope along a nnw sse trend the segment of the malta escarpment extending north of siracusa on the other hand is characterized by the presence of nnw sse east dipping recent extensional faults and related sedimentary basins the observed structural features support the occurrence of a lithospheric tear between the ionian oceanic basin and the hyblean plateau

reservoir zonation rock typing and compartmentalization of the tortonian serravallian sequence temsah gas field offshore nile delta egypt abstract the present study aims to evaluate the petrophysical properties and to discriminate the tortonian wakar and the serravallian sidi salem formations in the offshore temsah gas field north egypt into distinctive rock types the measured conventional core data includes helium and summation fluids porosities grain and bulk densities horizontal and vertical permeabilities as well as the water saturation also the reservoir quality index rqi flow zone indicator fzi and reservoir potentiality index rpi were calculated to establish a successful reservoir zonation in the temsah field the tortonian serravallian sequence has been discriminated into four reservoir rock types rrts which are described based on its lithologic composition as 1 sandy to argillaceous carbonates rrt1 2 siliceous pebbly sandstones rrt2 and 3 argillaceous to calcareous sandstones rrt3 and 4 calcareous to dolomitic sandstones rrt4 based on the petrophysical interpretation and ranking for the studied samples samples of rrt2 have very good rank due to presence of very good porosity excellent permeability and good to very good rqi and fzi values which are assigned as the best reservoir rock type in the tortonian serravallian sequence the petrophysical behavior of rrt4 shows the lowest reservoir quality impervious rqi and poor fzi the examined sequence has been sliced into reservoir zones each zone has its hydraulic flow unit range that represents the studied rock types in each zone based on the applied pressure tools including repeat formation tester rft and the modular formation dynamic tester mdt both the wakar and sidi salem reservoirs represent completely isolated compartments therefore ranking both reservoirs and estimating their hydrocarbon potential must be done separately for each reservoir

energetics of multidecadal atlantic ocean variability abstractoscillatory behavior of the atlantic meridional overturning circulation moc is thought to underlie atlantic multidecadal climate variability while the energy sources and sinks driving the mean moc have received intense scrutiny over the last decade the governing energetics of the modes of variability of the moc have not been addressed to the same degree this paper examines the energy conversion processes associated with this variability in an idealized north atlantic ocean model in this model the multidecadal variability arises through an instability associated with a so called thermal rossby mode which involves westward propagation of temperature anomalies applying the available potential energy ape framework from stratified turbulence to the idealized ocean model simulations the authors study the multidecadal variability from an energetics viewpoint the analysis explains how the propagation of the temperature anomalies leads to changes in ape which are subsequently converted into t

sea level change during the holocene in sardinia and in the northeastern adriatic central mediterranean sea from archaeological and geomorphological data abstract we provide new data on relative sea level change from the late holocene for two locations in the central mediterranean sardinia and ne adriatico they are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea level elevation twelve submerged archaeological sites were studied six aged between 2 5 and 1 6 ka bp located along the sardinia coast and a further six dated 2 0 ka bp located along the ne adriatic coast italy slovenia and croatia for sardinia we also use beach rock and core data that can be related to holocene sea level the elevations of selected significant archaeological markers were measured with respect to the present sea level applying corrections for tide and atmospheric pressure values at the time of surveys the interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea these data are compared with predictions derived from a new glacio hydro isostatic model associated with the last glacial cycle sardinia is tectonically relatively stable and we use the sea level data from this island to calibrate our models for eustatic and glacio hydro isostatic change the results are consistent with those from another tectonically stable site the versilia plain of italy the northeast adriatic italy slovenia and croatia is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions this indicates that the adriatic coast from the gulf of trieste to the southern end of istria has tectonically subsided by 1 5 m since roman times

quaternary normal faulting in southeastern sicily italy a seismic source for the 1693 large earthquake summary we present geological and morphological data combined with an analysis of seismic reflection lines across the ionian ovshore zone and information on historical earthquakes in order to yield new constraints on active faulting in southeastern sicily this region one of the most seismically active of the mediterranean is avected by wnw ese regional extension producing normal faulting of the southern edge of the siculo calabrian rift zone our data describe two systems of quaternary normal faults characterized by diverent ages and related to distinct tectonic processes the older nw se trending normal fault segments developed up to 400 kyr ago and striking perpendicular to the main front of the maghrebian thrust belt bound the small basins occurring along the eastern coast of the hyblean plateau the younger fault system is represented by prominent nnw sse trending normal fault segments and extends along the ionian ovshore zone following the ne sw trending avola and rosolini ispica normal faults these faults are characterized by vertical slip rates of 0 7 3 3 mm yr 1 and might be associated with the large seismic events of january 1693 we suggest that the main shock of the january 1693 earthquakes m 7 could be related to a 45 km long normal fault with a right lateral component of motion a long term net slip rate of about 3 7 mm yr 1 is calculated and a recurrence interval of about 550 50 yr is proposed for large events similar to that of january 1693

review of diagenetic facies in tight sandstones diagenesis diagenetic minerals and prediction via well logs abstract the tight sandstones are characterized by low porosity low permeability complex pore structure and strong heterogeneity due to the extensive diagenetic modifications they experienced understanding of the impact of diagenetic alterations on reservoir quality is crucial to the hydrocarbon exploration and production in tight sandstones diagenetic facies which is the comprehensive description of the diagenesis and diagenetic minerals determines the formation and distribution of sweet spot by correlating the diagenetic facies to well log responses the subsurface distribution of porosity and permeability can be predicted however the prediction of diagenetic facies and reservoir quality via well logs in tight sandstones remains a challenging task this paper critically reviews the impact of diagenesis and diagenetic minerals on reservoir quality in tight sandstones and establishes a model for prediction of diagenetic facies via well logs as assessed from peer reviewed papers in the literature as well as from the authors personal experiences this review begins with reviewing the impacts of compaction cementation dissolution and various types of diagenetic minerals on reservoir quality evolution the definition and classification schemes of diagenetic facies are then discussed and the reservoir quality as well as diagenetic evolution sequence of various diagenetic facies is summarized the same diagenetic facies commonly display similar compositional and textural attributes matrix and cement as well as porosity systems the well log responses gr ac den cnl and rt of various diagenetic facies are summarized by the calibration of log values with cores and related thin sections by translating the diagenetic facies to conventional well logs a predictable model which can be used for subsurface reservoir quality prediction is established then the theory of ecs logs is reviewed and the application of ecs logs in diagenetic facies evaluation is discussed at last the quantitative characterization for various type and degree of diagenesis is reviewed and the subsurface diagenetic facies is predicted by quantitative calculation of the compactional porosity loss cementational porosity loss and dissolution porosity content via well logs correlating the diagenetic facies to well logs provides a powerful tool to predict the distribution of high quality reservoirs in tight sandstones this review will provide insights into the reservoir quality evaluation and sweet spot prediction via well logs in tight sandstones

residual topography lithospheric structure and sunken slabs in the central mediterranean abstract the central mediterranean comprises subduction collision and backarc extension all in a relatively small area in this paper we analyze the topography of this region examining the influence of subducting slabs on overriding plates we take the observed surface elevation remove the contribution of the crust to it and use the residual topography to identify regions that are unusually low unusually high or normal then we calculate lithospheric thickness where local isostasy applies the results provide information about the structure of the lithosphere in this complex region and about the vertical tectonics in particular we found a difference between the south tyrrhenian subduction zone and the apennines consistent with the processes of slab rollback and slab break off respectively in the south tyrrhenian the edge of the oceanic plate is strongly pulled down whereas the edge of the overriding plate the calabrian peninsula is uplifted this opposite trend indicates weak plate coupling that is the subducting slab which is rapidly rolling back hangs almost entirely on the oceanic plate and the overriding plate is free in contrast in the apennines high residual topography and uplifting are detected on both sides of the mountain belt consistent with complete break off of the subducted lithosphere

climatic signature of two mid late holocene fluvial incisions formed under sea level highstand conditions pisa coastal plain nw tuscany italy abstract a multi proxy stratigraphic geomorphological palynological geophysical study of mid late holocene deltaic alluvial deposits beneath the pisa plain tuscany italy reveals short term enhances of fluvial activity under relative sea level highstand hst conditions last 7000 cal yr bp early hst delta progradation led to the progressive infill of a broad lagoon area 5000 cal yr bp followed by the development of a stable alluvial depositional environment 4000 cal yr bp the intense phase of alluvial aggradation was punctuated by two events of enhanced fluvial incision that cut down to 10 m the underlying lagoonal substrate the two erosive events which reflect centennial scale changes in the aggradation degradation ratio are chronologically constrained to the eneolithic bronze age transition 3800 cal yr bp and to the bronze iron age transition 2900 2800 cal yr bp respectively a detailed pollen profile highlights the correlation between these erosive events and two phases of increased humidity abies peaks 1 and 2 recorded in several sites of europe this correlation suggests a key role of climate fluctuations in triggering channel incision the peculiar high compressibility of the lagoonal substrate can also have acted as a factor able to foster the deepening of the channels in contrast the role of relative sea level changes and human impact on the activation of the two erosive processes appears negligible

isopycnal mixing in ocean circulation models abstract a subgrid scale form for mesoscale eddy mixing on isopycnal surfaces is proposed for use in non eddy resolving ocean circulation models the mixing is applied in isopycnal coordinates to isopycnal layer thickness or inverse density gradient as well as to passive scalars temperature and salinity the transformation of these mixing forms to physical coordinates is also presented

deformation of the 125 ka marine terrace in italy tectonic implications in peninsular italy marine terraces and shorelines created during oxygenisotope substage 5e known historically as the tyrrhenian highstand provide a reliable and homogeneous datum of vertical motions during the past 125 000 years published accounts of 121 locations on the tyrrhenian inner edge were reinterpreted and used to calculate both local and regional uplift rates the data show arching of southern italy between the tyrrhenian and the adriatic coasts and of the calabrian arc between the sangineto and the longi taormina tectonic lineaments at rates of up to 1 2 mm yr for the past 125 ka they also suggest that the present configuration of the southern apennines is the product of post early pleistocene regional uplift superimposed on tortonian to early pleistocene thrusting uplift patterns are characterised by different wavelength in different geodynamic settings suggesting a close link with the depth of the causative tectonic sources

sensitivity of the southern ocean overturning circulation to surface buoyancy forcing 1 the sensitivity of the southern ocean overturning to altered surface buoyancy forcing is investigated in a series of eddy permitting idealised simulations the modelled response indicates that heat and freshwater fluxes in the southern hemisphere mid latitudes may play a significant role in setting the strength of the overturning circulation enhanced buoyancy fluxes act to increase the meridional overturning up to a limit approaching the wind driven ekman transport the sensitivity of the overturning to surface buoyancy forcing is strongly dependent on the relative locations of the wind stress profile buoyancy forcing and upwelling region the numerical simulations provide support for the hypothesis that changes in upwelling during deglaciations may have been driven by changes in heat and freshwater fluxes instead of or in addition to changes in wind stress

the impact of diagenesis on the heterogeneity of sandstone reservoirs a review of the role of depositional facies and sequence stratigraphy diagenesis exerts a strong control on the quality and heterogeneity of most clastic reservoirs variations in the distribution of diagenetic alterations usually accentuate the variations in depositional porosity and permeability linking the types and distribution of diagenetic processes to the depositional facies and sequence stratigraphic framework of clastic successions provides a powerful tool to predict the distribution of diagenetic alterations controlling quality and heterogeneity the heterogeneity patterns of sandstone reservoirs which determine the volumes flow rates and recovery of hydrocarbons are controlled by geometry and internal structures of sand bodies grain size sorting degree of bioturbation provenance and by the types volumes and distribution of diagenetic alterations variations in the pathways of diagenetic evolution are linked to 1 depositional facies hence pore water chemistry depositional porosity and permeability types and amounts of intrabasinal grains and extent of bioturbation 2 detrital sand composition 3 rate of deposition controlling residence time of sediments at specific near surface geochemical conditions and 4 burial thermal history of the basin the amounts and types of intrabasinal grains are also controlled by changes in the relative sea level and therefore can be predicted in the context of sequence stratigraphy particularly in paralic and shallow marine environments changes in the relative sea level exert significant control on the types and extent of near surface shallow burial diagenetic alterations which in turn influence the pathways of burial diagenetic and reservoir quality evolution of clastic reservoirs carbonate cementation is more extensive in transgressive systems tract tst sandstones particularly below parasequence boundaries transgressive surface and maximum flooding surface because of the abundance of carbonate bioclasts and organic matter bioturbation and prolonged residence time of the sediments at and immediately below the sea floor caused by low sedimentation rates which also enhance the formation of glaucony eogenetic grain coating berthierine odinite and smectite formed mostly in tst and early highstand systems tract deltaic and estuarine sandstones are transformed into ferrous chlorite during mesodiagenesis helping preserve reservoir quality through the inhibition of quartz cementation the infiltration of grain coating smectitic clays is more extensive in braided than in meandering fluvial sandstones forming flow barriers in braided amalgamated reservoirs and may either help preserve porosity during burial because of quartz overgrowth inhibition or reduce it by enhancing intergranular pressure dissolution diagenetic modifications along sequence boundaries are characterized by considerable dissolution and kaolinization of feldspars micas and mud intraclasts under wet and warm climates whereas a semiarid climate may lead to the formation of calcrete dolocrete cemented layers turbidite sandstones are typically cemented by carbonate along the contacts with interbedded mudrocks or carbonate mudstones and marls as well as along layers of concentration of carbonate bioclasts and intraclasts commonly hybrid carbonate turbidite arenites are pervasively cemented proximal massive turbidites normally show only scattered spherical or ovoid carbonate concretions improved geologic models based on the connections among diagenesis depositional facies and sequence stratigraphic surfaces and intervals may not only contribute to optimized production through the design of appropriate simulation models for improved or enhanced oil recovery strategies as well as for co2 geologic sequestration but also support more effective hydrocarbon exploration through reservoir quality prediction

on the driving processes of the atlantic meridional overturning circulation because of its relevance for the global climate the atlantic meridional overturning circulation amoc has been a major research focus for many years yet the question of which physical mechanisms ultimately drive the amoc in the sense of providing its energy supply remains a matter of controversy here we review both observational data and model results concerning the two main candidates vertical mixing processes in the ocean s interior and wind induced ekman upwelling in the southern ocean in distinction to the energy source we also discuss the role of surface heat and freshwater fluxes which influence the volume transport of the meridional overturning circulation and shape its spatial circulation pattern without actually supplying energy to the overturning itself in steady state we conclude that both wind driven upwelling and vertical mixing are likely contributing to driving the observed circulation to quantify their respective contributions future research needs to address some open questions which we outline

assessing tectonic subsidence from estimates of holocene relative sea level change an example from the nw mediterranean magra plain italy new sedimentological sea level indicators are presented from the river magra coastal plain in nw italy chronologically well constrained paralic peats and organic sediments which had been deposited in a defined relationship with sea level were recovered in four of the seven boreholes considered in this work their evolution scatters in the time span of the past 6000 years since the cores are located within a single sedimentary basin it was possible to correct the elevation of marker horizons for the effect of sediment compaction by means of both a field and a geotechnical method thus seven reliable index points for the mid to late holocene sea level rise were obtained the age depth model derived from them was compared with that of sea level predictions from two different glacial isostatic adjustment gia models available for the area in both cases the modelled sea level estimates overlie the index points suggesting lower relative sea level elevation than the one predicted considering the combin

the eastern mediterranean mesozoic basin evolution and oil habitat 1 the eastern mediterranean mesozoic basin extends from northwestern egypt to southeastern turkey the basin originated in the triassic and early jurassic as continental blocks separated from north africa and arabia forming a zone of extension clastics carbonates and evaporites were deposited in an extensional sag basin and in grabens triassic carbonate reservoirs sealed by evaporites are oil and gas productive in syria and iraq jurassic paralic and shaly beds and basinal limestones deposited in the widening basin and in grabens are oil sources in egypt and israel from the middle jurassic to the late cretaceous the extensional basin became a passive margin on which clastics alternated cyclically with carbonate platforms this sequence provided sandstone and carbo ate reservoirs sealed by shale and marl late cretaceous convergence along the taurus zagros front and compression and shear in the platform and basin area coincided with regional high sea level organic rich chalk marl shale and limestone were deposited from the late cretaceous into the early tertiary over most of the basin area the greater part of known reserves in the region is derived from these beds which generated oil into multiple faulted reservoirs in deep grabens and downwarps from egypt to syria and into upper cretaceous to paleocene reef limestones in syria iraq and turkey

the energetics of a collapsing meridional overturning circulation a well studied example of natural climate variability is the impact of large freshwater input to the polar oceans simulating glacial melt release or an amplification of the hydrological cycle such forcing can reduce or entirely eliminate the formation of deep water in the polar latitudes and thereby weaken the atlantic meridional overturning circulation moc this study uses a series of idealized eddy permitting numerical simulations to analyze the energetic constraints on the atlantic ocean s response to anomalous freshwater forcing inthismodel thechangesinmocarenotcorrelatedwiththeglobalinputofmechanicalenergy both kinetic energy and available potential energy ape increase with northern freshwater forcing while the moc decreases however a regional analysis of ape density supports the notion that local maxima in ape density control the response of the moc to freshwater forcing perturbations a coupling between ape input and changes in local density anomalies accounts for the difference in time scales between the recovery and collapse of the moc

energetics of weakening and recovery of the atlantic overturning in a climate change simulation 1 an idealized climate change simulation is used to investigate the energetics of the atlantic meridional overturning circulation amoc at the stages of its weakening and recovery there is a good correlation between the strength of the amoc and the available potential energy ape in the upper 3 km of the ocean integrated north of 50 n or globally both during the weakening and recovery buoyancy forcing is important at both stages in the southern ocean the ape gradually builds up and correlates with the depth of pycnocline in the atlantic ocean this suggests that mechanical forcing plays an important role in the recovery of the amoc

deep burial diagenesis and reservoir quality evolution of high temperature high pressure sandstones examples from lower cretaceous bashijiqike formation in keshen area kuqa depression tarim basin of china the deep high temperature high pressure lower cretaceous bashijiqike sandstone buried to depths as great as 6 5 7 1km is an important natural gas reservoir in keshen gas field kuqa depression of the tarim basin reservoir quality is a critical risk factor in the development of these ultradeep reservoirs integrated approaches incorporating routine core analyses mineralogical petrographic and geochemical analyses have been used to investigate the diagenetic history of these rocks and their impact on reservoir quality with the aim to unravel the mechanisms for maintaining anomalously high porosities in sandstones that are buried to such a great depth these sandstones are dominantly fine to medium grained moderately to good sorted lithic arkoses and feldspathic litharenite most primary pores have been lost by mechanical compaction or carbonate cementation and the reduction of porosity by mechanical compaction was more significant than by cementation dissolution of framework grains contributed to the enhancement of reservoir quality eogenetic diagenetic alterations mainly include mechanical compaction precipitation of calcite cements and grain coating clays mesogenetic diagenesis is characterized by dissolution of framework grain by organic acids and subsequent precipitation of clay minerals and quartz infiltration of meteoric water related to teleodiagenesis would result in dissolution of the framework grains the meteoric leaching events during teleodiagenesis are of great importance for the bashijiqike sandstones grain coating clay minerals mixed layer illite smectite clays help to preserve porosity at depth by retarding quartz cementation and pressure solution the unique burial regime as early stage shallow burial with late stage rapid deep burial contributes to porosity preservation in eodiagenesis fluid overpressure caused by intense structural compression in the middle himalayan movement retarded compaction and helped preserve porosity in the late rapid deep burial stage anomalously high porosities are mainly found in medium grained good sorted sandstones with grain coating clays but with low clay and carbonate cement content of which the porosity is preserved primarily and enhanced secondarily the lowest porosities are associated with sandstones that are tightly compacted or cemented with carbonates or rich in detrital matrix porosity depth trends may vary significantly with lithofacies due to its differences in textural and compositional attributes five lithofacies are defined in terms of detrital composition and texture type and degree of diagenesis the reservoir quality prediction models of various lithofacies are constructed and the results of this study provide insights into mechanisms for maintaining anomalously high porosity and permeability in high temperature high pressure sandstone reservoirs and may help explain hydrocarbon distribution

submerged archaeological sites along the ionian coast of southeastern sicily italy and implications for the holocene relative sea level change abstract precise measurements of submerged archaeological markers in the siracusa coast southeastern sicily italy provide new data on relative sea level change during the late holocene four submerged archaeological sites have been studied and investigated through direct observations two of them are greek archaic in age 2 5 2 7 ka and are now 0 98 1 48 m below sea level the other two developed during the bronze age 3 2 3 8 ka and are now 1 03 1 97 m below sea level these archaeological data have been integrated with information derived from a submerged speleothem collected in a cave located along the siracusa coast at 20 m depth the positions of the archaeological markers have been measured with respect to present sea level corrected for tide and pressure at the time of surveys these data were compared with predicted sea level rise curves for the holocene using a glacio hydro isostatic model the comparison with the curve for the southeastern sicily coast yields a tectonic component of relative sea level change related to regional uplift uplift rates between 0 3 and 0 8 mm yr have been estimated

simulated impact of altered southern hemisphere winds on the atlantic meridional overturning circulation 1 previous work has suggested that the strength and latitudinal position of the southern hemisphere sh mid latitude westerly winds has an important impact on climate and the atlantic meridional overturning circulation amoc we probe this hypothesis by conducting ensembles of experiments using the gfdl cm2 1 coupled ocean atmosphere model with altered sh wind stress we find consistent with previous work that enhanced reduced and poleward equatorward displaced sh westerly winds lead to an amoc intensification weakening while the amoc takes more than a century to respond fully to the altered sh winds initial effects in the north atlantic can occur within a few decades the amoc changes generate sst and surface air temperature responses in the north atlantic and adjacent continental regions in the southern hemisphere the atmosphere responds to the altered ocean circulation with a further strengthening and poleward movement of the sh winds thereby constituting a modest positive feedback

faulting and earthquake triggering during the 1783 calabria seismic sequence summary between the 1783 february 5 and 1783 march 28 five earthquakes struck the southern part of calabria the main shock february 5 and the first aftershock february 6 devastated the region ene of the messina strait the greatest damage occurred along the foot of the aspromonte mountains south of san giorgio morgeto and along the tyrrhenian coast south of palmi a surface break about 18 km long with several feet of downthrow to the west formed along the cittanova santa cristina fault as a result of the main shock on february 7 a third large shock ruined villages at the foot of the serre mountains north of san giorgio morgeto morphological and structural evidence combined with a reassessment of observations made at the time of the earthquakes suggest that these three shocks were shallow 20 km and related to slip on the west dipping ne striking cittanova sant eufemia palmi scilla and serre normal faults respectively which juxtapose the basement of the aspromonte and serre mountains with the pleistocene deposits of the gioia tauro and mesima basins and border the palmi coastal high the three faults belong to an active rift that stretches from northern calabria to offshore the ionian coast of sicily the spatial coupling between the 1783 events is investigated by resolving changes of coulomb failure stress the main shock 1783 february 5 m 7 on the cittanova and sant eufemia faults increased that stress by several bars on the scilla fault triggering the 1783 february 6 earthquake m 6 5 the cumulative effect of these two shocks was to raise the coulomb stress by more than 1 bar on the sw part of the serre fault which was subsequently the site of the 1783 february 7 shock m 6 5 in turn the first three events increased the stress by about 1 bar on the ne part of this latter fault leading to the 1783 march 1 shock m 5 7 the gap between the 1783 february 7 and 1783 march 1 events may be related to the previous occurrence of an earthquake 124 yr before 1659 november 5 m 6 which had already released stress locally the occurrence of the last 1783 event 28 march is not as simply accounted for by coulomb modelling in part because it remains unclear which fault slipped and how deep this event was overall the 1783 sequence increased the coulomb failure stress by several bars south of the messina strait and north of the epicentral region of the 1693 se sicily catania noto earthquakes 125 yr later this same region was the site of the 1908 messina earthquake also a normal faulting event our study thus provides one convincing example in which coulomb stress modelling brings insight into the spatial dynamics of seismic sequences