the bucobello 322 ka fossil bearing volcaniclastic flow deposit in the eastern vulsini volcanic district central italy mechanism of emplacement and insights on human activity during mis 9 abstract we present a multidisciplinary study of a fossiliferous site located in the vulsini volcanic district on the western side of the tiber river valley north of rome highlighting the peculiar geologic factors that contributed to the origin and preservation of an outstanding archaeological record testifying of the early human frequentation in this region mighty explosive eruptions since at least 500 ka affected the investigated area eventually culminating in the formation of the huge bolsena caldera tectonic deformation accompanying volcanic activity caused large fault displacements shaping the ground surface and contributing to route the path and possibly to trigger the catastrophic emplacement of volcaniclastic flows a sedimentary trap originated by fault scarp cutting through a streambed was likely the cause for the large accumulation of bones and stone artifacts ripped up and carried by a volcaniclastic flow at 322 ka the analysis of the fossil assemblage reveals both gnawing traces by carnivores and cut marks from the percussion tools employed by humans to butch the carcasses however the occurrence of retouched and unretouched blanks within the lithic assemblage also testifies for provenance from a wider area of human activity which included hunting and scavenging probably at a nearby butchering site

m2 baroclinic tide variability modulated by the ocean circulation south of japan we analyze a concurrent simulation result of the ocean circulation and tidal currents using a data assimilative ocean general circulation model covering the western north pacific with horizontal resolution of 1 36 to investigate possible interactions between them four sites of active m2 internal tide variability in open ocean hot spots such as tokara strait izu ridge luzon strait and ogasawara ridge are detected from both the satellite observation and the simulation energy cycle analysis of the simulated m2 baroclinic tide indicates two types of the hot spots dissipation tokara strait and izu ridge and radiation luzon strait and ogasawara ridge dominant sites energy conversion from barotropic to baroclinic m2 tides at the hot spots is modulated considerably by the lower frequency changes in the density field modulation at the two spots tokara strait and izu ridge is affected by the kuroshio path variation together with the seasonal variation of the shallow thermocline at the other two sites influence from changes in the relatively deep stratification through the kuroshio intrusion into south china sea luzon strat and mesoscale eddy activity ogasawara ridge is dominant in the modulation

shear wave splitting and subcontinental mantle deformation splitting observations are interpreted in terms of the strain induced lattice preferred orientation of mantle minerals especially olivine we consider three hypotheses concerning the origin of the continental anlsotropy 1 strain associated with absolute plate motion as in the oceanic upper mantle 2 crustal stress and 3 the past and present internal deformation of the subcontinental upper mantle by tectonic episodes it is found that the last hypothesis is the most successful namely that the most recent significant episode of internal deformation appears to be the best predictor of q for stable continental regions this is interpreted as fossil anisotropy whereas for presently active regions such as alaska the anisotropy reflects present day tectonic activity in the stable portion of north america there is a good correlation between delay time and lithospheric thickness this is consistent with the anisotropy being localized in the subcontinental lithosphere and suggests that intrinsic anisotropy is approximately constant the acceptance of this hypothesis has several implications for subcontinental mantle deformation first it argues for coherent deformation of the continental lithosphere crust and mantle during orogenies this implies that the anisotropic portion of the lithosphere was present since the deformational episode and rules out the addition of undeformed material to this layer by subsequent underplating or conductive growth of the thermal boundary layer one of the most important issues in the study of orogenies is the need to reconcile the formation of thickened lithosphere with the paradoxically high mantle temperatures often associated with orogenic episodes most efforts to date have focussed on modes of deformation whereby the cold lithospheric mantle is removed by convective instability or delamination and replaced by warm asthenosphere these models however are incompatible with the evidence for preserved coherent lithospheric deformation rather the deformed mantle appears to have been heated in place we suggest that the elevated mantle temperatures may be due to the strain heating accompanying the deformation

complex anisotropy in d beneath the eastern pacific from sks skks splitting discrepancies article i nfo although observations of seismic anisotropy in the lowermost mantle are abundant the mechanism which generates anisotropy in the d layer is not well understood most observational constraints on d anisotropy come from the splitting of shear waves that propagate nearly horizontally through the lowermost mantle however anisotropy in the d layer can also give rise to discrepancies in shear wave splitting for sks and skks phases for the same event station pair as these phases sample different regions of the lowermost mantle here i report observations of strongly discrepant sks skks splitting observed at broadband stations in western mexico and california in particular strong skks splitting with fast polarization directions near 60 and delay times up to 3 s is observed for a group of raypaths that sample a region of the d layer beneath the eastern pacific ocean a comparison of skks splitting with sks splitting observed from the same events as well as with sks splitting observed at a variety of backazimuths at each station suggests that the anomalous anisotropic structure is in the lowermost mantle my preferred model for the unusual anisotropic geometry in this region is large shear deformation in d at the edge of a region where slab material impinges upon the core mantle boundary resulting in lattice preferred orientation of lower mantle minerals

major explosive activity in the monti sabatini volcanic district central italy over the 800 390 ka interval geochronological geochemical overview and tephrostratigraphic implications abstract a review of the existing chronological stratigraphic and chemo petrologic data of the major eruptive units from the early phase of activity 800 390 ka in the monti sabatini volcanic district msvd belonging to the ultra potassic magmatic region of central italy is presented along with new radioisotopic age determinations and geochemical analyses through the combined use of electron microprobe glass compositions selected trace element compositions and single crystal 40ar 39ar age determinations we provide a new chrono and chemo stratigraphic classification of the products emplaced in the 800 390 ka time interval besides giving insights on the petrologic evolution of the roman comagmatic region the large dataset provides fundamental information that is applicable to tephrostratigraphic studies in the wide region encompassing the tyrrhenian sea margin to the adriatic sea basin distal tephras from this volcanic activity also act as important geochronologic markers for the coastal sedimentary successions deposited in response to glacio eustatic fluctuations as well as for successions in the quaternary tectonic basins of the central and southern apennines an innovative approach based on the use of discrimination diagrams of zr y vs nb y ratios for fingerprinting altered volcanic rocks recently developed and successfully employed in archaeometric studies is here combined to the glass compositions for classifying the msvd deposits and tested on two distal tephra layers showing its potentiality for tephrostratigraphic correlation

small scale lateral variations in azimuthally anisotropic d structure beneath the cocos plate abstract shear waves from intermediate and deep focus south american events recorded by california broadband seismometers reveal complex anisotropy in the lowermost mantle scs waves densely sample the d region beneath the cocos plate just west of central america 1 16 n 267 277 e our data show evidence for significant near source anisotropy which we constrain for each event by performing polarization analyses on an expanded dataset of s waveforms scs waveforms are corrected for upper mantle and near source anisotropy and estimates of d anisotropy are made using the covariance method we find splits between fast and slow components of scs ranging from 0 4 to 2 5 s with an average of 1 6 s fast polarization directions in the southern portion of our study area are approximately orthogonal to the raypaths north of 7 latitude there is a rapid change in fast polarization direction to nearly raypath parallel beyond 10 latitude fast directions are more highly scattered than in southern regions past work in the region has inferred strong lateral variations in shear wave velocity but fairly uniform transverse isotropy in contrast our results indicate that the lowermost mantle beneath the cocos plate has azimuthal anisotropy that varies laterally over scales of 100 200 km in addition our data suggest connections between previously imaged topography on the d discontinuity and the character of anisotropy

history of glacial terminations from the tiber river rome insights into glacial forcing mechanisms 1 we document the aggradational history of the tiber river delta through the last 17 000 years by means of 17 new 14c ages from peat or wood collected from the delta sediment an abrupt change in sediment clast size grading from gravel to clay occurred between 13 63 0 20 and 12 80 0 15 ka indicating that it was synchronous with the last glacial termination with no appreciable phase lag knowing this phase relationship enables us to reduce the magnitudes of age uncertainties for aggradational sections corresponding to glacial terminations ix through iii which we had dated previously by 40ar 39ar methods glacial terminations viii vi and iv precede beyond 95 confidence the ages predicted by northern hemisphere summer insolation maxima additionally we find that each of these seven glacial terminations follows particularly mild insolation minima which we suggest may be regarded as the preconditioning factor to trigger a glacial termination

direct observations of microscale turbulence and thermohaline structure in the kuroshio front 1 direct observations of microstructure near the kuroshio front were conducted in august 2008 and october 2009 these show negative potential vorticity pv in the mixed layer south of the front where directly measured turbulent kinetic energy dissipation rates are an order magnitude larger than predicted by wind scaling these elevated dissipation rates scale better with an empirical scaling which considers local wind and ekman buoyancy flux driven by downfront wind near zero pv in the thermocline under the kuroshio mainstream is observed at 200 300 m depth with dissipation exceeding open ocean thermocline values by factors of 10 100 overall the large turbulent dissipation rates measured in the kuroshio can be categorized into two groups one characterized by low richardson number along the kuroshio front thermocline and the other characterized by high stratification away from the kuroshio mainstream the former is attributed to mixing by unbalanced frontal ageostrophic flows and the latter is attributed to internal wave breaking on average both groups appear in regions of large horizontal density gradients observed thermohaline structure shows low salinity tongues from the surface to over 300 m depth and deep cold tongues extending upward from 500 to 100 m depth in a narrow 20 km zone suggesting down and upwelling driven by geostrophic straining which is confirmed by quasigeostrophic omega equation solutions this implies that adiabatic along isopycnal subduction and diabatic diapycnal turbulent mixing acting in tandem at the kuroshio front likely contribute to npiw formation

variable azimuthal anisotropy in earth s lowermost mantle a persistent reversal in the expected polarity of the initiation of vertically polarized shear waves that graze the d layer the layer at the boundary between the outer core and the lower mantle of earth in some regions starts at the arrival time of horizontally polarized shear waves full waveform modeling of the split shear waves for paths beneath the caribbean requires azimuthal anisotropy at the base of the mantle models with laterally coherent patterns of transverse isotropy with the hexagonal symmetry axis of the mineral phases tilted from the vertical by as much as 20 are consistent with the data small scale convection cells within the mantle above the d layer may cause the observed variations by inducing laterally variable crystallographic or shape preferred orientation in minerals in the d layer

fluvial deposits as an archive of early human activity river terraces are well established as an important source of lower and middle palaeolithic artefacts in europe large collections having been assembled there during the years of manual gravel extraction now that many terrace sequences can be reliably dated and correlated with the oceanic record potentially useful patterns can be recognized in the distribution of artefacts the earliest appearance of artefacts in terrace staircases marking the arrival of the first tool making hominins in the region in question is the first of several archaeological markers within fluvial sequences the lower to middle palaeolithic transition with the appearance of levallois is another others may be more regional in significance the occurrences of clactonian mode 1 industry twisted ovate handaxes and bout coupe handaxes for example igcp project no 449 instigated the compilation of fluvial records from all over the old world comparison between british and central european sequences confirms the established view that there is a demarcation between handaxe making in the west and flake core industries in the east other centres of activity reported here have been in the middle east syria south africa and india data from such areas will be key in deciphering the story of the earlier out of africa migration that by pre homo sapiens people there is clear evidence for diachroneity between the first appearances of different industries in keeping with the well established idea of northward migration

high resolution investigation of shear wave anisotropy in d beneath the cocos plate 1 broadband shear wave signals from 16 deep south american earthquakes are used in a high resolution analysis of lowermost mantle structure beneath the cocos plate shear wave splitting of 162 scs phases is generally compatible with vertical transverse isotropy vti in the d region with little path length or spatial dependence across the 200 800 km2 area sampled assuming a 250 km thick d layer the vti has an average value of 0 63 scs s differential travel time anomalies for the same data indicate a lateral gradient in positive d transverse component velocity perturbations increasing northward s wave triplication arrivals from a shear velocity discontinuity at the top of d show splitting similar to the scs phases but with smaller magnitude vertical resolution remains limited but the data are consistent with vti material being concentrated in just the upper portion or at the top and bottom of d

observations of changing anisotropy across the southern margin of the african llsvp we present evidence for the presence of complex anisotropy in the lowermost mantle from 3 d waveform modelling of observed core diffracted shear waves that sample the southern edge of the african large low shear velocity province llsvp the anomalously strong amplitude of the sv component for the shear core diffracted phase at large distances indicates the presence of anisotropy we measure shear wave splitting parameters to determine which part of the elastic tensor is constrained by this particular data set the modelling is performed using the spectral element method the anisotropy is strong outside the llsvp weakens or rotates close to its boundary and appears to be absent inside the llsvp the presence of the llsvp margin may cause flow in the mantle to change direction the occurrence of strong anisotropy in the region of fast seismic velocities is compatible with lattice preferred orientation in post perovskite due to accommodation of flow through dislocation creep

new chronological framework mis 13 9 and depositional context for the lower palaeolithic sites north west of rome revisiting the early hominin in central italy abstract the paleolithic period in central italy is currently undergoing an extensive revision due to a significant chronological re examination of many archaeological sites recently several lower palaeolithic sites 20 km nw of rome previously dated within mis 9 335 300 ka i e la polledrara di cecanibbio torre in pietra castel di guido malagrotta and four sites along via aurelia have been geochronologically reassessed between 412 and 325 ka these sites in which abundant fauna artifacts and hominin remains have been found are remarkably well preserved a combination of geological factors and the peculiar geodynamic conditions of this region where tectonics volcanism and glacio eustatic forcing worked in concert allowed for the exceptional conservation of the remains in this paper we provide a review of these sites and analyze their depositional contexts showing that rapid filling of the fluvial incisions during glacial terminations combined with sudden emplacement of volcanic deposits caused the sealing of the archaeological materials accumulated at the bottom of the paleo valleys the aim of this paper is to contribute to a better understanding of these sites as well as to provide the archaeological implications of their new chronology and depositional contexts results allow to reconsider the hominin presence in central italy and highlight the importance to integrate archaeological investigations with modern geological studies combining sedimentological geochronological geomorphological and chronostratigraphical methods

evidence of enhanced turbulent dissipation in the frontogenetic kuroshio front thermocline 1 enhanced turbulent dissipation o 10 8 10 7 wkg 1 in the thermocline on the cyclonic side of the kuroshio front was observed during a period of frontogenesis using a microstructure profiler xbt and adcp along 143 e across the kuroshio front in august 2008 the eddy diffusivity corresponding to the mixing below the central jet is estimated to be o 10 4 10 3 m2 s 1 the strong turbulent mixing we observed in the kuroshio is in sharp contrast to previous field measurements which found that small scale diapycnal mixing in western boundary currents remains at levels typically measured in the open ocean thermocline the turbulence in the kuroshio is attributed to frontogenesis arising out of an estimated confluence rate of o 10 5 s 1 based on satellite altimeters suggesting the ubiquity of a forward energy cascade from mesoscale to microscale turbulence near ocean fronts as indicated by recent theoretical studies

ambiguities in human and elephant interactions stories of bones sand and water from castel di guido italy geoarchaeological and taphonomical studies have been carried out on the sequence and on the faunal remains of castel di guido central italy a middle pleistocene site with acheulean industry and faunas including elephas palaeoloxodon antiquus bos primigenius equus ferus and other taxa investigation focused on remains accumulated on the bottom of a depressed area probably an ephemeral stream channel sometimes acting as a seep the assemblage resulted prevalently from human activity as shown by the selection of the faunas by the thorough fracturing of the bones and by the occurrence of abundant chipped stone industry and bone bifaces it is still a matter of debate whether the animals were hunted or scavenged the present day distribution of the remains does not represent exactly their original configuration as in most sites of this type and age more likely the objects are partly in their original position and partly reworked and lie within a complex palimpsest of several phases of fluvial transport and human activity with the addition of external inputs of reworked bones and artefacts

three dimensional structure of frontal waves and associated salinity minimum formation along the kuroshio extension abstract high resolution hydrographic observations were conducted in september 2002 to describe the detailed structure of frontal waves along the kuroshio extension frontal waves were observed both in the upper and intermediate layers which corresponded to the depths of north pacific subtropical mode water and north pacific intermediate water respectively the frontal wave in the upper layer preceded the intermediate depth frontal wave by about 1 4 wavelength the vertical phase lag created situations in which the low salinity oyashio water in the intermediate layer was superimposed below the upper layer high salinity kuroshio water thus forming a vertical salinity minimum the frontal waves with a wavelength of about 200 km and a phase speed of 0 2 0 3 m s 1 propagating in the downstream direction were consistent with those from satellite images vertical velocity fields were estimated with the quasigeostrophic omega equation downwelling around the trough from the crest to trough of the intermedia

strong internal waves generated by the interaction of the kuroshio and tides over a shallow ridge abstractthe kuroshio and tides significantly influence the oceanic environment off the japanese mainland and promote mass heat transport however the interaction between the kuroshio and tides int

spontaneous generation of near inertial waves by the kuroshio front abstractwhile near inertial waves are known to be generated by atmospheric storms recent observations in the kuroshio front find intense near inertial internal wave shear along sloping isopycnals even during calm weather recent literature suggests that spontaneous generation of near inertial waves by frontal instabilities could represent a major sink for the subinertial quasigeostrophic circulation an unforced three dimensional 1 km resolution model initialized with the observed cross kuroshio structure is used to explore this mechanism after several weeks the model exhibits growth of 10 100 km scale frontal meanders accompanied by o 10 mw m 2 spontaneous generation of near inertial waves associated with readjustment of submesoscale fronts forced out of balance by mesoscale confluent flows these waves have properties resembling those in the observations however they are reabsorbed into the model kuroshio front with no more than 15 dissipating or radiating away thus spontaneous generation o

patterns of shear and turbulence across the florida current abstract measurements by the multi scale profiler msp at seven stations spanning the straits of florida characterize levels and patterns of internal wave activity and mixing in this vertically sheared environment contrasting properties suggest five mixing regimes the largest and most vast is the interior regime where the background flow has an inverse richardson number ri 1 ranging up to 0 55 shear is dominated by fluctuations that are 1 4 times stronger than in the open ocean and turbulent diffusivities are similarly moderate at 1 4 10 5 m2 s 1 the high velocity core of the current near the surface at midchannel is associated with weak mixing to its west is a zone of high mean shear where strong stratification results in background ri 1 of only 0 4 fluctuations are weak and diffusivity is moderate intermittent shear features beneath the core have mean ri 1 1 and strong turbulence two regimes are related to channel topography adjacent to the steep eastern slope finescale shear is

paleo surfaces of glacio eustatically forced aggradational successions in the coastal area of rome assessing interplay between tectonics and sea level during the last ten interglacials abstract recently acquired geochronological and stratigraphic data provide new information on the sedimentary successions deposited by the paleo tiber river in the coastal and near coastal area of rome in consequence of the glacio eustatic changes allowing to better define their inner geometry and palaeogeographic spatial distribution in the present work we use this revised sedimentary dataset to provide a geochronologically constrained and tectonically adjusted record of paleo sea level indicators aimed at this scope we review literature data acquired in the last 35 years and using the new geochronological constraints we pinpoint the coastal to fluvial terraces of mis 5 and mis 7 mapping their relic surfaces in an area of 30 km along the coast north and south of the tiber river mouth and 20 km inland of the fluvial valleys of tiber and aniene rivers the geometry of these paleo surfaces provides constraints on the relative elevation of the sea level during the last interglacials and on the uplift rates in this region during the last 200 ka in particular we recognize the previously undetected terraces of mis 5 3 and mis 5 1 interstadials and we assess their spatial relationship with respect to mis 5 5 providing important information on sea level oscillations during this time span comparison with sea level indicators provided by previous aggradational successions deposited during past interglacials spanning mis 9 through mis 21 in the coastal area of rome also allows us to reconstruct the tectonic history and investigate its relationships with the middle pleistocene volcanic activity of the roman comagmatic region along the tyrrhenian sea margin of italy in the last 900 ka

chronostratigraphic constraints on middle pleistocene faunal assemblages and acheulian industries from the cretone lacustrine basin central italy integrated 40ar 39ar trace element stratigraphic palaeontological and palaethnological data provide geochronological and biochronological constraints for the sedimentary and tectonic history of a middle pleistocene fluvial lacustrine basin near rome cretone basin central italy which has yielded a significant record of mammal fossil remains and palaeolithic industry this work is a case study of the interplay between tectonics and glacio eustacy which strongly influenced the evolution of the tyrrhenian sea margin of central italy dating of tephra layers interbedded within the cretone basin lacustrine succession and reconstruction of relict terraced surfaces allow correlation with similar geochronologically constrained marine isotopic stages mis 15 5 terraced deposits along the coast coupled extensional tectonics and regional uplift over the last 600 ka caused the progressive uplifting and westward migration of the main fluvial lacustrine basin and the formation of a smaller satellite basin at its eastern margin here stable environmental conditions during mis 13 5 indicated continuous human and large mammal frequentation as testified by lithic industry and fossil remains ascribable to the acheulean and later early middle palaeolithic technocomplexes and galerian aurelian mammal faunas respectively in addition to providing independent age constraints to glacial sea level oscillations of this region the reconstructed chronostratigraphic setting for the cretone basin provides evidence for one of the oldest acheulean lithic assemblage of central italy as well as new biochronological and palaeobiogeographical data for some middle pleistocene mammal species of italy

fluvial deposits as an archive of early human activity progress during the 20 years of the fluvial archives group fluvial sedimentary archives are important repositories for lower and middle palaeolithic artefacts throughout the old world especially in europe where the beginning of their study coincided with the realisation that early humans were of great antiquity now that many river terrace sequences can be reliably dated and correlated with the globally valid marine isotope record potentially useful patterns can be recognized in the distribution of the find spots of the artefacts that constitute the large collections that were assembled during the years of manual gravel extraction this paper reviews the advances during the past two decades in knowledge of hominin occupation based on artefact occurrences in fluvial contexts in europe asia and africa as such it is an update of a comparable review in 2007 at the end of igcp project no 449 which had instigated the compilation of fluvial records from around the world during 2000 2004 under the auspices of the fluvial archives group an overarching finding is the confirmation of the well established view that in europe there is a demarcation between handaxe making in the west and flake core industries in the east although on a wider scale that pattern is undermined by the increased numbers of lower palaeolithic bifaces now recognized in east asia it is also apparent that although it seems to have appeared at different places and at different times in the later lower palaeolithic the arrival of levallois technology as a global phenomenon was similarly timed across the area occupied by middle pleistocene hominins at around 0 3 ma

anisotropy in the deep earth abstract seismic anisotropy has been found in many regions of the earth s interior its presence in the earth s crust has been known since the 19th century and is due in part to the alignment of anisotropic crystals in rocks and in part to patterns in the distribution of fractures and pores in the upper mantle seismic anisotropy was discovered 50 years ago and can be attributed for the most part to the alignment of intrinsically anisotropic olivine crystals during large scale deformation associated with convection there is some indication for anisotropy in the transition zone particularly in the vicinity of subducted slabs here we focus on the deep earth the lower mantle and core where anisotropy is not yet mapped in detail nor is there consensus on its origin most of the lower mantle appears largely isotropic except in the last 200 300 km in the d region where evidence for seismic anisotropy has been accumulating since the late 1980s mostly from shear wave splitting measurements recently a picture has been emerging where strong anisotropy is associated with high shear velocities at the edges of the large low shear velocity provinces llsvps in the central pacific and under africa these observations are consistent with being due to the presence of highly anisotropic mgsio 3 post perovskite crystals aligned during the deformation of slabs impinging on the core mantle boundary and upwelling flow within the llsvps we also discuss mineral physics aspects such as ultrahigh pressure deformation experiments first principles calculations to obtain information about elastic properties and derivation of dislocation activity based on bonding characteristics polycrystal plasticity simulations can predict anisotropy but models are still highly idealized and neglect the complex microstructure of polyphase aggregates with strong and weak components a promising direction for future progress in understanding the origin of seismic anisotropy in the deep mantle and its relation to global mantle circulation is to link macroscopic information from seismology and microscopic information mineral physics through geodynamics modeling anisotropy in the inner core was proposed 30 years ago to explain faster p wave propagation along the direction of the earth s axis of rotation as well as anomalous splitting of core sensitive free oscillations there is still uncertainty about the origin of this anisotropy in particular it is difficult to explain its strength based on known elastic properties of iron as it would require almost perfect alignment of iron crystals indeed the strongly anomalous p travel times observed on paths from the south sandwich islands to alaska may or may not be due to inner core anisotropy and will need to be explained before consensus can be reached on the strength of anisotropy in the inner core and its origin

inertia gravity waves spontaneously generated by jets and fronts part i different baroclinic life cycles abstract the spontaneous generation of inertia gravity waves in idealized life cycles of baroclinic instability is investigated using the weather research and forecasting model two substantially different life cycles of baroclinic instability are obtained by varying the initial zonal jet the wave generation depends strongly on the details of the baroclinic wave s development in the life cycle dominated by cyclonic behavior the most conspicuous gravity waves are excited by the upper level jet and are broadly consistent with previous simulations of o sullivan and dunkerton in the life cycle that is dominated by anticyclonic behavior the most conspicuous gravity waves even in the stratosphere are excited by the surface fronts although the fronts are no stronger than in the cyclonic life cycle the anticyclonic life cycle also reveals waves in the lower stratosphere above the upper level trough of the baroclinic wave these waves have not been previously identified in idealized simulations the sensiti

a three dimensional radially anisotropic model of shear velocity in the whole mantle summary we present a 3 d radially anisotropic s velocity model of the whole mantle saw642an obtained using a large three component surface and body waveform data set and an iterative inversion for structure and source parameters based on non linear asymptotic coupling theory nact the model is parametrized in level 4 spherical splines which have a spacing of 8 the model shows a link between mantle flow and anisotropy in a variety of depth ranges in the uppermost mantle we confirm observations of regions with vsh vsv starting at 80 km under oceanic regions and 200 km under stable continental lithosphere suggesting horizontal flow beneath the lithosphere we also observe a vsv vsh signature at 150 300 km depth beneath major ridge systems with amplitude correlated with spreading rate for fast spreading segments in the transition zone 400 700 km depth regions of subducted slab material are associated with vsv vsh while the ridge signal decreases whilethemid mantlehasloweramplitudeanisotropy vsv in the lowermost 300 km which appears to be a robust conclusion despite an error in our previous paper which has been corrected here the 3 d deviations from this signature are associated with the large scale low velocity superplumes underthecentralpacificandafrica suggestingthatvsh vsv isgeneratedinthepredominant horizontal flow of a mechanical boundary layer with a change in signature related to transition to upwelling at the superplumes

plinian activity during the early eruptive history of the sabatini volcanic district central italy abstract the early activity of the sabatini volcanic district svd central italy was characterised by highly explosive eruptions that produced widespread subplinian and plinian fall deposits in this study four major eruptive units informally named as units a b c and d were recognised in the 514 449 ka age interval in particular unit d was emplaced during the early phase of the 449 ka tufo rosso a scorie nere pyroclastic flow forming eruption the most important event in the whole svd activity history estimates of relevant eruptive parameters indicate tephra fall volumes up to 4 km3 for individual units peak eruption column heights in the range of 14 29 km and corresponding mass eruption rates of 7 8 106 1 3 108 kg s isopach and isopleth maps of fallout deposits as well as the distribution of the proximal lag breccia of the tufo rosso a scorie nere consistently indicate a common vent area which does not correspond to any volcanic centre identified up to now in the svd this was located along ne sw trending tectonic lineaments that also controlled the location of the other major volcanic centres of the svd the characterisation by means of field aspects grain size componentry and density and chemical composition of juvenile clasts renders the studied fall deposits as valuable stratigraphic markers for the svd and well beyond it in fact their wide areal dispersals toward the e and se may allow correlations on a regional scale for the quaternary successions of intermountain basins of the central apennine and the adriatic sea basin successions finally the correct identification of distal tephra from plinian and co ignimbrite plumes and their attribution to specific explosive eruptions of the svd and the other volcanic districts of the roman province rather than to local intra apennine centres provides crucial implications for geodynamic reconstructions

lateral variations in d thickness from long period shear wave data we explore global variations in d shear wave structure by examining 12 years of long period global digital seismograph network gdsn data to identify reflected phases from the d layer in the lowermost mantle we restrict our search to epicentral distances between 63 and 74 where a precritical d reflection will lie between the s and scs arrivals with gdsn long period records a d signal at these ranges is generally obscured by the stronger neighboring phases so to isolate the d reflections we develop a technique for stripping away the interfering s and scs waveforms we interpret travel time variations in the observed sds phases in terms of variations in d thickness and generate maps of inferred d thickness for areas of good seismic coverage the regions of observed d reflections are beneath australasia north central asia the arctic alaska and central america we find considerable variation in d structure in these regions a result consistent with previous studies which have found evidence for lateral heterogeneity in d on average the estimated d thickness is 260 km but there is a fairly uniform distribution of thicknesses between 150 km and 350 km a possible correlation is observed between d thickness and regions of predicted strong horizontal mantle flow

energetics of barotropic and baroclinic tides in the monterey bay area abstracta detailed energy analysis of the barotropic and baroclinic m2 tides in the monterey bay area is performed the authors first derive a theoretical framework for analyzing internal tide energetics based on the complete form of the barotropic and baroclinic energy equations which include the full nonlinear and nonhydrostatic energy flux contributions as well as an improved evaluation of the available potential energy this approach is implemented in the stanford unstructured nonhydrostatic terrain following adaptive navier stokes simulator suntans results from three dimensional high resolution suntans simulations are analyzed to estimate the tidal energy partitioning among generation radiation and dissipation a 200 km 230 km domain including all typical topographic features in this region is used to represent the monterey bay area of the 152 mw energy lost from the barotropic tide approximately 133 mw 88 is converted into baroclinic energy through internal tide generation and 42 56

geochemical and sr nd isotopic characterization of middle pleistocene sediments from the paleontological site of la polledrara di cecanibbio sabatini volcanic district central italy abstract six stratigraphically related samples of freshwater sediments from the middle pleistocene paleontological site of la polledrara di cecanibbio to nw of rome in the sabatini volcanic district svd have been characterized by their mineralogical geochemical and sr nd isotopic compositions these volcaniclastic sediments filled a valley incised by a former watercourse flowing through volcanic rocks the samples are composed of abundant analcite after leucite subordinate augite sanidine fluorite except for the stratigraphically deepest and most sio 2 poor sample and minor anorthite quartz is present only in the stratigraphically uppermost samples the mineralogical composition is consistent with the origin of the sediments from different source rocks of the svd major and trace elements allow for distinguishing among the samples in particular the four stratigraphically uppermost samples share close sio 2 intermediate between the contents of the other two samples although several chemical characteristics of the polledrara samples can be explained by impact of supergene processes on the sediments the overall composition supports an origin from different source rocks of the svd in particular the tufi stratificati varicolori di la storta tfvls and older pyroclastic rocks the 87 sr 86 sr ratios of the samples 0 710182 0 710433 support the distinction of the sediments based on chemistry and mineralogy and their sabatinian origin the isotopic range overlaps that in the lavas of phases iii iv of the svd and is slightly lower than the range in the tfvls likely because of advanced analcitization of the sediments the ammonium acetate extracts from the samples show a narrow isotopic range 0 709613 0 709735 which is lower than the range of the bulk sediments but close to the isotopic composition of fossil elephant remains in the polledrara sediments lastly except for the most sio2 rich sample exhibiting a higher value 0 512227 the 143 nd 144 nd ratios of the other samples show a narrow range 0 512147 0 512171 and cannot be distinguished from each other the isotopic range is similar to that of the tfvls but higher than that of sabatinian lavas supporting the origin of the sediments from the former rocks

lowermost mantle anisotropy beneath the north pacific from differential s scs splitting summary seismic anisotropy is an important tool for studying the nature origin and dynamics of the lowermost mantle d we introduce differential s scs splitting as a tool for removing the effect of near source and near receiver anisotropy to estimate splitting accrued in the d region this is applicable to events recorded at epicentral distances between 60 and 85 near source anisotropy has often been ignored in previous studies of lowermost mantle anisotropy we apply differential s scs splitting to records from canadian national seismic network stations of western pacific earthquakes these sample the lowermost mantle beneath the north pacific the residual splitting in scs which we attribute to d shows lag times between 1 0 and 3 9 s given the near horizontal ray path of scs in d we interpret the recovered fast directions as the orientation of the fast shear wave in the plane defined by the vertical and transverse directions and observe a clearly non vti transverse isotropy with a vertical axis of symmetry style of anisotropy the largest population of results shows an approximately southeasterly dipping symmetry axis which we speculate might be explained by descending palaeoslab material being swept horizontally across the core mantle boundary towards an upwelling region beneath the central pacific non vti symmetry and the many possible contributions to d anisotropy from lower mantle minerals melt and subducted materials suggest that our understanding of the lowermost mantle could be greatly improved by trying to resolve a more general style of anisotropy

ongoing research at the late middle pleistocene site of la polledrara di cecanibbio central italy with emphasis on human elephant relationships abstract the site of la polledrara di cecanibbio latium italy is related to deposits of the pg6 sequence middle pleistocene aurelia formation mis 10 and 9 the sediments are mainly volcaniclastic in composition and constitute the filling of incised valleys mainly characterized by fluvial deposits at the base passing upward to fluvio lacustrine and palustrine deposits containing abundant fossil mammal remains and artifacts the arrangement of the specimens and taphonomic observations suggest that most of the transport of the bones occurred during flooding events followed by progressive swampy phases resulting in the formation of areas with stagnant and muddy waters where some elephants became trapped as indicated by remains in partial anatomical articulation recent excavations carried out at the site permit a better definition of the palaeoenvironmental reconstruction already partially outlined in previous publications in particular an area showing a close correlation between the skeleton of an elephant and human activity allows documentation and better understanding of some aspects of human elephant interaction probably mainly represented by scavenging activity

d anisotropy beneath southeast asia 1 earthquakes from the banda sea and flores sea region recorded at the kyrgyz network in the tien shan region show evidence for anisotropy in the lowermost mantle beneath south east asia shear wave splitting is measured for the scs phase after a receiver side correction is applied individual results show scatter in measured time lag and fast direction but stacking these gives a stable estimate of 0 8 0 04 s and 43 4 degrees this equates to a fast shear wave with a polarisation deviation from horizontal at the bounce point of around 9 degrees the simplest model to explain is a transversely isotropic medium with a slight dip to the east and an inferred anisotropy of 0 25 this is compatible with previous observations of vsh vsv for this region scenarios which might explain the observed anisotropy include sheared melt pockets or aligned post perovskite crystals associated with palaeosubduction of the pacific plate and indian plate

dynamics and energetics of trapped diurnal internal kelvin waves around a midlatitude island abstractthe generation of trapped and radiating internal tides around izu oshima island located off sagami bay japan is investigated using the three dimensional stanford unstructured nonhydrostatic terrain following adaptive navier stokes simulator suntans that is validated with observations of isotherm displacements in shallow water the model is forced by barotropic tides which generate strong baroclinic internal tides in the study region model results showed that when diurnal k1 barotropic tides dominate resonance of a trapped internal kelvin wave leads to large amplitude internal tides in shallow waters on the coast this resonance produces diurnal motions that are much stronger than the semidiurnal motions the weaker freely propagating semidiurnal internal tides are generated on the western side of the island where the m2 internal tide beam angle matches the topographic slope the internal wave energy flux due to the diurnal internal tides is much higher than that of the semidiurnal tides

shear wave splitting at central tien shan evidence for rapid variation of anisotropic patterns at active collisional belts the fast polarization axis of shear wave splitting is generally aligned parallel to the strike of the belt which has been proposed to indicate mantle strain that is coherent with crustal deformation a notable exception is central tien shan where anomalous patterns of splitting have previously been observed we here analyze shear wave splitting of sks phases across north central tien shan using digital data from the kyrgyzstan broadband seismic network knet we find a pattern of short wavelength anisotropic heterogeneity that supports complex mantle flow due to small scale convection the along strike variations in mantle structure contrast with the coherent pattern of crustal shortening and indicate that mantle flow is not directly coupled to crustal deformation in this region

palaeoloxodon exploitation at the middle pleistocene site of la polledrara di cecanibbio rome italy the site of la polledrara di cecanibbio rome central italy clearly documents a close connection between elephant remains and the subsistence strategies of human beings a carcass of a straight tusked elephant was recently discovered in sediments that represent the edge of a former swampy area some limbs are still in anatomical connection and the skeleton is associated with a lithic industry that according to taphonomic data was produced in situ the spatial distribution of elephant bones exceptionally well preserved because of the characteristics of the sediment allows hypothesizing the dynamics of death and burial the almost complete articulated skeleton lies gently bent on its left side though the anterior and posterior limbs maintain a nearly standing position the forelimbs are pointing slightly downward the left hind limb is stretched while the knee of the right one is bent downward with the foot sole facing up the anatomical connection of the bones association excludes any fluvial transport even though some skeletal elements such as vertebrae ribs pelvis and scapulae are missing the carcass belongs to an adult palaeoloxodon antiquus as suggested by the morphological and biometric characteristics of molariform teeth and long bones a large quantity of lithic tools was recovered around the carcass mainly along its right side the presence of more than six hundred lithic implements cores tools flakes and working debris some of them presenting wear traces indicating their use on soft animal tissues meat and hide and associated with the elephant skeleton documents human activity related to the exploitation of the carcass by scavenging the lithic industry on small flint pebbles was produced at the site as indicated by the refitting and by the presence of working debris and indicates very simple chaines operatoires traces of intentional fracturing on the femurs evidence the exploitation on the elephant carcass by humans a marrow extraction and the procurement of raw material for the production of bone tools are also documented by various remains found in sediments deposited during both fluvial and palustrine phases

seismic anisotropy of oceanic upper mantle shear wave splitting methodologies and observations we develop methodologies to obtain accurate measurements of shear wave splitting and apply these techniques to examine the pattern of oceanic upper mantle anisotropy to obtain high quality estimates of receiver splitting at island stations we devise a stacking method that finds the optimum splitting parameters and 95 error region for teleseismic shear wave phases from a suite of earthquake events to obtain additional measurements in oceanic regions we develop techniques to measure splitting parameters and errors for ss phases that sample upper mantle anisotropy at their bounce points however we find the data are often of low resolution and anomalous characteristics are sometimes found that make splitting difficult to interpret ten second splitting of ss is observed across the banjo seismic array but we cannot unambiguously attribute this signal to mantle anisotropy at the bounce the receiver splitting methods are used to assess the adequacy of a two anisotropic layer model for the pacific region with fast polarization azimuth in the lithosphere oriented in the fossil spreading direction and in the asthenosphere oriented in the absolute plate motion direction this model has been proposed to explain surface wave data in the pacific ocean but our splitting results demonstrate that oceanic anisotropy patterns are more heterogeneous than would be predicted while the island splitting measurements could reflect the influence of individual hotspot upwellings hotspot effects do not appear to be universally dominant we propose that splitting observations alternatively indicate broad scale differences in the underlying character of oceanic upper mantle anisotropy associated with coherant patters of lithospheric structure and asthenospheric flow in particular splitting surface wave models and regional studies all support a model where lithospheric anisotropy throughout the south pacific has been erased or reoriented toward the absolute plate motion direction whereas more limited observations in the north pacific indicate that the fossil lithospheric signature appears to be preserved

shear wave splitting and waveform complexity for lowermost mantle structures with low velocity lamellae and transverse isotropy 1 shear waves that traverse the lowermost mantle exhibit polarization anomalies and waveform complexities that indicate the presence of complex velocity structure above the core mantle boundary synthetic seismograms for horizontally and vertically polarized shear waves sh and sv respectively are computed using the reflectivity method for structures with low velocity sheets lamellae and for comb like models approximating long wavelength vertical transverse isotropy vti motivated by evidence for partial melt in the deep mantle lamella parameter ranges include 1 vp from 5 to 10 vs 3 vp 2 100 to 300 km thickness of vertical stacks of lamella 3 lamella spacing and thickness varying from 0 5 to 20 km and 4 lamellae concentrated near the top bottom or throughout the d region at the base of the mantle such lamellae represent in effect horizontally emplaced dikes within d excessively complex waveforms are produced when more than 20 of d volume is comprised of low velocity lamellae many lamellae models can match observed sdiff splitting 1 10 s delays of svdiff but typically underpredict scs splitting 1 4 s delays of scsv vti model parameters are selected to address d observations and include 1 0 5 to 3 anisotropy 2 discontinuous d shear velocity increases up to 3 3 d thicknesses from 100 to 300 km and 4 vti concentrated at the top bottom or throughout d vti models readily match observed splits of scs and sdiff we discuss lamellae and vti model attributes in relationship to waveform complexities splitting magnitude triplications from a high velocity d discontinuity and apparently reversed polarity svdiff onsets the possible presence of melt filled lamellae indicates that local chemical or thermal perturbations can produce regions that exceed the solidus within d such melt could occur in the bulk of d because the melt is either close to neutral buoyancy advective velocities exceed percolative velocities or both

observations of near inertial internal gravity waves radiating from a frontal jet abstractshipboard adcp and towed ctd measurements are presented of a near inertial internal gravity wave radiating away from a zonal jet associated with the subtropical front in the north pacific three dimensional spatial surveys indicate persistent alternating shear layers sloping downward and equatorward from the front as a result depth integrated ageostrophic shear increases sharply equatorward of the front the layers have a vertical wavelength of about 250 m and a slope consistent with a wave of frequency 1 01f they extend at least 100 km south of the front time series confirm that the shear is associated with a downward propagating near inertial wave with frequency within 20 of f a slab mixed layer model forced with shipboard and ncep reanalysis winds suggests that wind forcing was too weak to generate the wave likewise trapping of the near inertial motions at the low vorticity edge of the front can be ruled out because of the extension of the features well south of it instead the authors

barotropic and baroclinic m2 tides in the monterey bay region abstract a high resolution 250 m primitive equation model is used to simulate the depth averaged and baroclinic m2 tides in the monterey bay region the model shows a high level of skill in comparisons with sea level observations adcp current observations within the submarine canyon are reasonably well reproduced the modeled depth averaged currents have a complex spatial pattern with magnitudes in excess of 0 1 m s 1 near moss landing during the second half of flood ebb tide the flow is into out of the bay through the canyon but out of into the bay over the shelf regions this depth averaged flow pattern is not evident in a diagnostic run implying a feedback between the internal tides and the pressure gradient in the bay the depth integrated baroclinic total minus depth averaged energy fluxes show a complex beamlike pattern due to the interaction of energy from multiple sources the beams have magnitudes up to 1 kw m 1 interspersed with regions of near zero depth integrated flux energy en

independent 40ar 39ar and 14c age constraints on the last five glacial terminations from the aggradational successions of the tiber river rome italy we use 13 new 40ar 39ar and 4 new 14c datings of volcanic deposits and organic material found within near coastal aggradational successions deposited by the tiber river near rome italy to integrate a larger dataset previously achieved in order to offer independent age constraints to the sea level fluctuations associated with late quaternary glacial cycles during the last 450 ka results are compared with the chronologically independently constrained red sea relative sea level curve and with the astronomically tuned deep sea benthic 18o record we find good agreements for the timings of change and in several cases for both the amplitudes and timings of change during glacial terminations t 1 t 2 t 3 and t 5 there is one striking exception namely for glacial termination t 4 that led into interglacial marine isotope stage mis 9 t 4 in our results is dated a full 18 ka earlier than in the red sea and deep sea benthic 18o records which are in good agreement with each other in spite of their independent chronological constraints the observed discrepancy is beyond the scale of the combined age uncertainties one possible explanation is that the documented aggradation represents an early phase triggered by a smaller event in the sea level record but the thickness of the aggradational sediment sequence then suggests that the amplitude of this earlier sea level rise is underestimated in the red sea and benthic 18o records also this would imply that the aggradational succession of the main t 4 deglaciation has not yet been located in the study region which is hard to reconcile with our extensive fieldwork and borehole coverage unless unlikely non deposition or complete erosion resolving this discrepancy will improve understanding of the timing of deglaciations relative to the orbitally modulated insolation forcing of climate and will require further focused research both into the nature and chronology of the tiber sequences of this period and into the chronologies of the red sea and deep sea benthic 18o records

azimuthal anisotropy in the d layer beneath the caribbean 1 the lowermost mantle beneath central america has anisotropic seismic velocity structure manifested in shear wave splitting of signals from south american earthquakes recorded at north american broadband recording stations prior studies of deep mantle anisotropy in this region have characterized the structure as having vertical transverse isotropy vti which is sufficient to explain a general trend of early tangential sh component arrivals however vti models cannot quantitatively match systematic waveform complexities in the onset of many of the shear waves that graze this region after accounting for splitting effects of upper mantle anisotropy beneath the recording stations we model the corrected waveform data using full wave theory for mantle velocity models with an anisotropic d layer this is the first attempt to quantitatively model a large data set including azimuthal anisotropy in d the models include transverse isotropy with either a vertical or tilted symmetry axis the latter resulting in azimuthal anisotropy for some initial shear wave polarizations tilted transverse isotropy tti produces small reversed polarity arrivals on the sv components at the arrival time of sh consistent with the data geographical variations in the azimuth of the tti symmetry axis are indicated by the data the lack of azimuthal coverage prevents unique resolution of the tti orientation and also precludes distinguishing between tti and other azimuthal anisotropy structures such as that predicted for lattice preferred orientation of minerals nonetheless our modeling demonstrates the need for laterally varying anisotropic structure of more complex form than vti for this region

generation mechanism of internal waves by tidal flow over a sill the generation mechanism of internal waves by relatively strong tidal flow over a sill is clarified analytically special attention is directed to the role of the tidal advection effect which is examined by use of characteristics an internal wave which propagates upstream is gradually formed over the sill through the interference among infinitesimal amplitude internal waves elementary waves emanated from the sill at each instant of time in the accelerating decelerating stage of tidal flow the effective amplification of an internal wave takes place as the froude number exceeds falls below unity because during this period the internal wave slowly travels downstream upstream crossing over the sill where elementary waves are efficiently superimposed when the strength of the tidal advection effect is appropriate the internal wave formed in the accelerating stage ac wave and that formed in the decelerating stage dc wave overlap so that the resultant wave height becomes very large since the relative position of ac and dc waves varies depending on the strength of the tidal advection effect the resultant internal wave form is strongly affected by it when the tidal advection effect is strong the ac wave is carried too far downstream to interfere with the dc wave and hence the resultant wave form consists of two crests and two troughs when the tidal advection effect is moderate the optimum interference between ac and dc waves occurs and the resultant wave form consists of one crest and one trough with its horizontal scale approaching that of the sill when the tidal advection effect is weak the internal wave height becomes very small since elementary waves propagate almost freely in the tidal flow without coming close together and the resultant wave form approaches a sinusoidal wave of tidal frequency

how islands stir and fertilize the upper ocean 1 large differences between the upstream and lee side flow characteristics of an isolated island in the kuroshio have been identified from a three dimensional velocity survey and from vertical profiles of fine and micro structure in the island wake the relative vorticity is o 10f the horizontal current divergence indicates upwelling of o 0 01 m s 1 and the rate of dissipation of kinetic energy is o 10 4 w kg 1 isopycnal surfaces shoal by 60 m on the lee side and surface nitrate concentration increases seven fold flow blockage by the island and the izu ogasawara ridge on its flanks induces horizontal and vertical flow separation the associated lateral and vertical shear drive the upwelling and the vertical mixing in the wake and produces a very pronounced island mass effect

the history of the monti sabatini and alban hills volcanoes groundwork for assessing volcanic tectonic hazards for rome abstract the volcanic rocks of rome provide chronostratigraphic constraint that is of use to geologists archaeologists and paleontologists identifying the areal distribution of these rocks their mode of emplacement and a detailed chronology of the eruptive events also is crucial for assessing local natural hazards in a volcanic tectonic context and for recognizing whether the volcanoes may erupt again in the future we have identified and dated many of the volumetrically significant eruptive units from the monti sabatini and alban hills colli albani and propose a formalized volcanic stratigraphy for rome it is probable that seismic events triggered some eruptions as several ignimbrites from the two volcanoes have statistically indistinguishable ages following a 200 kyr period of dormancy that was coincident with a pulse of regional uplift the alban hills appears to have begun recently circa 45 ka a new eruptive cycle therefore accurate assessment of volcanic tectonic hazards and estimation of possible future volcanic activity is necessary for the safety of the five million people living near these volcanoes

suspended particulate layers and internal waves over the southern monterey bay continental shelf an important control on shelf mud belts 1 physical and optical measurements taken over the mud belt on the southern continental shelf of monterey bay california documented the frequent occurrence of suspended particulate matter features the majority of which were detached from the seafloor centered 9 33 m above the bed in fall 2011 an automated profiling mooring and fixed instrumentation including a thermistor chain and upward looking acoustic doppler current profiler were deployed at 70 m depth for 5 weeks and from 12 to 16 october a long range autonomous underwater vehicle performed across shelf transects individual spm events were uncorrelated with local bed shear stress caused by surface waves and bottom currents nearly half of all observed spm layers occurred during 1 week of the study 9 16 october 2011 and were advected past the fixed profiling mooring by the onshore phase of semidiurnal internal tide bottom currents at the start of the 9 16 october period we observed intense near bed vertical velocities capable of lifting particulates into the middle of the water column this updraft event appears to have been associated with nonlinear adjustment of high amplitude internal tides over the mid and outer shelf these findings suggest that nonlinear internal tidal motions can erode material over the outer shelf and that once suspended this spm can then be transported shoreward to the middle and shallow sections of the mud belt this represents a fundamental broadening of our understanding of how shelf mud belts may be built up and sustained

lower mantle tomography and phase change mapping a lower mantle s wave triplication scd has been recognized for many years and appears to be explained by the recently discovered perovskite pv to postperovskite ppv phase change seismic observations of scd display 1 rapid changes in strength and timing relative to s and scs and 2 early arrivals beneath fast lower mantle regions while the latter feature can be explained by a clapeyron slope of 6 mpa k and a velocity jump of 1 5 when corrected by tomographic predictions it does not explain the first feature here we expand on this mapping approach by attempting a new parameterization that requires a sample of d near the scs bounce point vs where the phase height hph and velocity jump are functions of vs these parameters are determined by modeling dense record sections collected from usarray and passcal data where grand s tomographic model is the most detailed in d structure beneath central america we also address the range of to generate new global models of the phase boundary and associated temperature variation we conclude that a near 9 mpa k is most satisfactory but requires to be nonuniform with a range from about 1 0 to 4 0 with some slow region samples requiring the largest values moreover the edges of the supposed buckled slabs delimitated by both p and s waves display very rapid changes in phase boundary heights producing scd multipathing these features can explain the unstable nature of the scd phase with easy detection to no detection commonly observed the fine structure at the base of the mantle beneath these edges contains particularly strong reflections indicative of local ultralow velocity zones which are predicted in some dynamic models

structure constraints and instability leading to the post perovskite phase transition of mgsio3 abstract recent experience with rietveld refinement of structural analogues and literature surveys suggests anion anion repulsion limits the stability of the perovskite phase including in the mgsio3 perovskite to post perovskite transition assuming rigid octahedral coordination still to be tested experimentally the critical point where intra and inter octahedral anion anion distances are equal provides a useful metric for predicting the pressure of the perovskite post perovskite transition and the clapeyron slope of the phase boundary once pressure and temperature derivatives of relevant structure parameters are known the inter octahedral anion anion distances and the polyhedral volume ratio are rigorously formulated as a function of octahedral rotation in this work assuming the orthorhombic pbnm perovskite structure where regular octahedra share each corner and conform to the in and anti phase rotation schemes designated by space group symmetry these mathematical expressions are consistent with structure data from 70 perovskite structured materials surveyed in the literature at ambient as well as extreme conditions and define structure constraints such as the minimum polyhedral volume ratio which must be reached before the phase transition to the post perovskite structure type can proceed the formalism we present is general for perovskite pbnm and dependent on the accuracy with which structures can be determined from sometimes compromised high pressure diffraction data

a nonhydrostatic mesoscale ocean model part i well posedness and scaling abstract the incompressibility and hydrostatic approximations that are traditionally used in large scale oceanography to make the hydrodynamic equations more amenable to numerical integration result in the primitive equations these are ill posed in domains with open boundaries and hence not well suited to mesoscale or regional modeling instead of using the hydrostatic approximation the authors permit a greater deviation from hydrostatic balance than what exists in the ocean to obtain a system of equations that is well posed with the specification of pointwise boundary conditions at open or solid boundaries these equations formulated with a free surface boundary model the mesoscale flow field accurately in all three dimensions even the vertical it is essential to retain the vertical component of the coriolis acceleration in the model since it is nonhydrostatic

a potential post perovskite province in d beneath the eastern pacific evidence from new analysis of discrepant sks skks shear wave splitting

inferences on flow at the base of earth s mantle based on seismic anisotropy we applied global waveform tomography to model radial anisotropy in the whole mantle we found that in the last few hundred kilometers near the core mantle boundary horizontally polarized s wave velocities vsh are on average faster by 1 than vertically polarized s wave velocities vsv suggesting a large scale predominance of horizontal shear this confirms that the d region at the base of the mantle is also a mechanical boundary layer for mantle convection a notable exception to this average signature can be found at the base of the two broad low velocity regions under the pacific ocean and under africa often referred to as superplumes where the anisotropic pattern indicates the onset of vertical flow

mesoscale eddy internal wave coupling part i symmetry wave capture and results from the mid ocean dynamics experiment abstract vertical profiles of horizontal velocity obtained during the mid ocean dynamics experiment mode provided the first published estimates of the high vertical wavenumber structure of horizontal velocity the data were interpreted as being representative of the background internal wave field and thus despite some evidence of excess downward energy propagation associated with coherent near inertial features that was interpreted in terms of atmospheric generation these data provided the basis for a revision to the garrett and munk spectral model these data are reinterpreted through the lens of 30 years of research rather than representing the background wave field atmospheric generation or even near inertial wave trapping the coherent high wavenumber features are characteristic of internal wave capture in a mesoscale strain field wave capture represents a generalization of critical layer events for flows lacking the spatial symmetry inherent in a parallel shear flow or isolated vortex

p and s wave reflectors in d beneath southeast asia summary earthquakes from the south pacific region recorded at the kyrgyz seismic network knet and the ghengis network both part of the tien shan continental dynamics study have been analysed to search for evidence of reflections from the d region the reflection points of this source receiver combination are in a seismically fast area beneath southeast asia employing several array methods we find evidence for reflections from a d reflector in both p and s waves the reflector depth generally agrees for both wave types there is some evidence for a second deeper reflector in this region migrating the data suggests a lower seismic reflector beneath the northeastern end of the study region the waveforms of p and s waves imply that the upper reflector has a negative impedance contrast for p but a positive impedance contrast for s several possibilities are discussed for generating the observed reflector s with the post perovskite phase transition in combination with a cold slab being the preferred explanation

a new age within mis 7 for the homo neanderthalensis of saccopastore in the glacio eustatically forced sedimentary successions of the aniene river valley rome abstract field observations as well as borehole sedimentological and geochronologic data allow us to reconstruct the geologic setting of the aniene river valley in northern rome framing it within the recently recognized picture of temporally constrained glacio eustatically forced aggradational successions of this region the sedimentary successions cropping out in this area include those described in the literature of the early 20th century in saccopastore where two skulls of homo neanderthalensis were recovered based on the geometry elevation and sedimentologic features of the investigated sedimentary deposits the stratigraphic record of saccopastore is correlated with the aggradational succession deposited in response to sea level rise during glacial termination iii at the onset of mis 7 i e 250 ka corresponding to the local vitinia formation as opposed to previous correlation with the mis 5 interglacial and a locally defined tyrrhenian stage 130 ka this previous attribution was based on the interpretation of the sedimentary succession of saccopastore occurring between 15 and 21 m a s l as a fluvial terrace formed around 130 ka during the riss wurm interglacial ca 6 m above the present day alluvial plain of the aniene river in contrast to this interpretation a 40ar 39ar age of 129 2 ka determined for this study on a pyroclastic flow deposit intercalated in a fluvial lacustrine sequence forming a terrace 37 m a s l near the coast of rome constrains the aggradational succession in this area to mis 5 precluding the occurrence of an equivalent fluvial terrace at lower elevation in the inland sector of saccopastore we therefore interpret the stratigraphic record of saccopastore as the basal portion of the aggradational succession deposited in response to sea level rise during mis 7 whose equivalent fluvial terrace occurs around 55 m a s l in this region we also review the published paleontological and paleoethnological records recovered in saccopastore and demonstrate their compatibility with the faunal assemblages and lithic industries occurring in the sedimentary deposits of the vitinia formation while we show the lack of any unequivocal late pleistocene mis 5 affinity we therefore propose that the chronostratigraphic position of the saccopastore deposits containing the two skulls should be around 250 000 years as opposed to a previously preferred age of 130 000 years the revised age makes these skulls the oldest italian occurrences of h neanderthalensis and provides evidence for a substantially coeval appearance and evolutionary path with respect to central northern europe

anisotropy as cause for polarity reversals of d reflections recordings of seismic events that sample the deep mantle can test different hypotheses of mantle processes and composition seismic reflections from structures in the d region the bottom 200 400 km of the earth s mantle can provide information on the velocity contrasts in this region by studying the waveforms and polarities of the d reflections in p and s waves we can potentially distinguish between different explanations for the observed structures such as phase transitions mineral texture or thermal anomalies here we use source receiver combinations that contain reflections from d in two different regions that are both characterised by fast seismic velocities in tomographic models beneath the caribbean a positive s velocity contrast but negative p wave velocity contrast across the d reflector has been reported previously consistent with a model of a phase change in mgsio3 in the second fast velocity region eurasia we detect positive p and s wave velocity contrasts in two orthogonal paths crossing in the lowermost mantle indicating a different scenario for d a path that crosses this region in 45 to the other two great circle paths shows evidence for a negative p velocity contrast one explanation to reconcile observations in both regions is a phase transition from perovskite to post perovskite with a fraction of 12 preferred crystal alignment in the post perovskite phase depending on the travel direction of the waves with respect to the flow direction in the lower mantle positive or negative velocity jumps can be expected other anisotropic models are considered but cannot fully explain the range of observations we find in the data c 2011 elsevier b v all rights reserved

tidal synchronicity of the 26 december 2004 sumatran earthquake and its aftershocks 1 the frequency of earthquake incidence along the andaman sunda java trench plate boundary region has been investigated for the ten lunar month period 28 october 2004 19 august 2005 encompassing the 26 december 2004 earthquake during this period variations in earthquake activity correlate with the tidal force cycles maxima in earthquake activity occur around the times of new and full moons typically lagging by 0 3 days this relationship is consistent with earthquake inducement via ocean tidal loading also during this period the earthquake incidence associated with new and full moons at the western end of the region was a 38 and b 86 higher than the period averages for the full and declustered major earthquake catalogs respectively

in the elephant everything is good carcass use and re use at castel di guido italy abstract castel di guido is a typical middle pleistocene elephant site where intentionally fragmented bones of elephant and of other large mammals were found together with acheulean biface like industry including bifaces made of various stone types and of elephant bone associated with flint tools on pebbles and flakes following a first interpretation of the evidence the site represented a single and short phase of use and elephants horses aurochs and few other species were killed and butchered on site or partly brought to the site to be butchered after having been killed elsewhere the bones were intentionally fractured for marrow extraction and left to season before being used as raw material for artefact production further evidence deriving from more recent studies suggests that the site lasted for much longer time and is in fact an intricate palimpsest of several phases of human use and partial reworking castel di guido results largely from anthropic processes deriving from peculiar behavioural aspects of the early neandertal groups that frequented the site the carcasses of various taxa were exploited for food and the elephant ones also for raw material in bone tool production this choice was probably due to limited availability of good quality flint or other hard rocks in the area because of these characteristics castel di guido is an ideal ground for exploring the aspects of use re use and recycling of food and raw material resources and of tools several stone and some bone tools show clear evidence of recycling such as subsequent knapping or refashioning phases put into evidence by different wear of the surfaces these characteristics point to long continuity of use of the site for similar purposes which is in accordance with the very different preservation of the remains that were partly reworked by short range fluvial processes these aspects indicate that the bones of large taxa mostly elephant were part of a complex subsistence system characterised by hunting and scavenging on one side and an extremely fuzzy boundary among use re use and recycling on the other one this system was based on the recycling or transfunctionalisation of the carcasses which were exploited for food consumption meat and possibly marrow and later for raw material procurement over a long time of permanence and availability on the surface of the site

correlation of fluviodeltaic aggradational sections with glacial climate history a revision of the pleistocene stratigraphy of rome volcanic horizons interbedded with fluviodeltaic clastic sediments of the tiber and fosso galeria river valleys near rome provide a unique opportunity to date five middle pleistocene fining upward aggradational sections 40 ar 39 ar ages from the interbedded volcanic beds illustrate that aggradation occurred on an approximate 100 k y cycle and was initiated by sea level rise associated with glacial melting the age constraint additionally shows that aggradation occurs rapidly in response to sea level change and thus ages from volcanic strata within the aggradational sections provide high resolution constraint on the timing of relative sea level rise the established chronology is consistent with other glacial proxies and their radioisotopically or orbitally based time scales for the timing of glacial terminations vi and v but is significantly older than most records for the timing of termination iii ultimately the age of each termination should be determined by radioisotopic means and to that end the work here shows that fluviodeltaic sedimentology provides valuable information for middle pleistocene time scale calibration

reassessing the sedimentary deposits and vertebrate assemblages from ponte galeria area rome central italy an archive for the middle pleistocene faunas of europe abstract the ponte galeria area is part of the larger campagna romana and hosted the inner delta of the tiber river since the beginning of the middle pleistocene allowing the deposition of a series of glacio eustatically controlled fluvial lacustrine sedimentary successions very rich in fossil mammal remains due to its richness of fossiliferous sites this area represents an exceptional archive for the study and understanding of the biochronological paleobiogeographical and paleoenvironmental evolution during the middle pleistocene in europe a series of recent studies using the 40 ar 39 ar ages of tephra intercalated within the sedimentary deposits provided a large amount of geochronological data linking these aggradational successions to the different marine isotopic stages in the present paper we present a complete review of the faunal assemblages identified so far in the ponte galeria area and we constrain the ages of the faunal units by placing them within the new chronostratigraphic scheme by means of this interdisciplinary approach we re calibrate the mammal assemblages collected in this area and reconstruct a new biochronological and paleobiogeographic framework for the italian peninsula during the middle pleistocene in particular we distinguish six well defined biochronological units slivia ponte galeria isernia fontana ranuccio torre in pietra and vitinia in the studied area covering a time span of ca 0 6 myr from the early to middle pleistocene transition to at least marine isotope stage 7 this period is characterized in europe by the mid pleistocene revolution global climate change and by the transition at first between villafranchian and galerian taxa and later between the galerian and aurelian ones according to the reviewed data the persistence of villafranchian taxa is recorded in italy at the beginning of the middle pleistocene probably due to favorable climatic conditions or delay in dispersal of competitive species while the faunal turnover between the villafranchian and galerian species was completed around 0 6 0 5 ma during this time bos primigenius and other temperate warm taxa were widespread in the peninsula earlier than in western europe in contrast typical aurelian taxa usually related with temperate cold climatic conditions ursus spelaeus megaloceros giganteus occurred later in italy than in other western european areas