space weathering of asteroid surfaces abstract visible and near infrared spectra of reflected sunlight from asteroid surfaces exhibit features that hold the promise for identifying surface mineralogy however the very surfaces that are observed by remote sensing are also subject to impingement by micrometeoroids and solar wind particles which are believed to play the dominant role in space weathering which is the time dependent modification of an asteroid s reflectance spectrum such space weathering has confused the interpretations of telescopic spectra of asteroids especially concerning the possible association of common ordinary chondritic meteorites with so called s type asteroids recent spacecraft studies of asteroids especially of eros by near shoemaker have documented aspects of space weathering processes but we still do not understand the physics of space weathering well enough to confidently assay mineralogy of diverse asteroids by remote sensing a review of the intellectual history of this topic reveals the complexity of

mid infrared lightcurve of vesta abstract we present a thermal mid infrared lightcurve of asteroid 4 vesta and use this to infer variations in thermophysical properties over the surface vesta was observed over three nights during the may 2007 opposition with the infrared telescope facility on mauna kea mid infrared observations are compared to a model based on the standard thermal model which is draped over a vesta shape model derived from hubble space telescope observations a visible lightcurve with similar aspect was used to estimate the albedo as vesta rotates shape and albedo can explain some of the features observed in the mid infrared lightcurve however variations in the thermophysical properties such as the beaming parameter over vesta s surface are required to completely explain the observations in order to match the mid infrared magnitudes observed of vesta a beaming parameter of 0 862 is required which is higher than other main belt asteroids such as ceres and pallas 0 756 indicating a smoother and or rockier surface on vesta variations in the beaming parameter with longitude are invoked to reproduce the observed thermal variations surface materials with relatively high beaming values indicating a smoother and or rockier surface in the eastern hemisphere of vesta coincide with locations where impact excavations may have produced surfaces that are younger and brighter relative to the western hemisphere

holocene hydrological changes in south western mediterranean as recorded by lake level fluctuations at lago preola a coastal lake in southern sicily italy abstract this paper presents a high resolution lake level record for the holocene at lago preola sicily southern italy based on a specific sedimentological approach with a chronology derived from ams radiocarbon dates it gives evidence of three major successive palaeohydrological periods with 1 a pronounced dryness during the early holocene until ca 10300 cal bp 2 a highstand from ca 10300 to 4500 cal bp and 3 a marked lowstand from 4500 cal bp to present large amplitude lake level fluctuations characterise two transition phases at ca 10300 9000 and 6400 4500 cal bp period 2 was interrupted between 8300 and 7000 cal bp by a dry phase that was punctuated to ca 7300 cal bp by the deposition of a tephra from neighbouring pantelleria island comparisons of the preola record with other palaeohydrological records along north south and west east transects in the mediterranean show contrasting patterns of hydrological changes north south of around 40 n latitude the records highlight a mid holocene period characterised by lake level minima maxima humid mid holocene conditions over the mediterranean south of 40 n were probably linked to a strong weakening of the hadley cell circulation and of monsoon winds we suggest that the maximum of humidity in the mediterranean during the mid holocene was characterised by humid winters to the north of 40 n and humid summers to the south on a multi centennial scale the high resolution palaeohydrological reconstructions in the central mediterranean area reveal a strong climate reversal around 4500 4000 cal bp with contrasting changes in the hydrological cycle in addition to seasonal and inter hemispherical changes related to orbital forcing this major oscillation might be related to non linear responses of the climatic system to the gradual decrease in summer insolation at northern latitudes another major climate oscillation around 7500 7000 cal bp may have resulted from the combined effects of 1 a strong rate of change in insolation and 2 variations in solar activity finally comparisons of the preola lake level record with sicilian pollen records suggest a strong influence of moisture availability on vegetation development in sicily very dry early holocene conditions probably prevented the expansion of coastal evergreen forests while decreasing moisture availability since the onset of the late holocene may have exacerbated effects of intensive land use

a magnetic anomaly associated with an albedo feature near airy crater in the lunar nearside highlands 1 we describe a strong crustal magnetic anomaly recently identified in lunar prospector magnetometer data that is associated with a previously unreported albedo feature near the crater airy in the lunar nearside highlands other workers have demonstrated a correlation between magnetic anomalies and the enigmatic bright markings known as lunar swirls we have used earth based telescopic spectra and clementine multispectral images to investigate the compositional and optical maturity characteristics of the airy swirl the airy albedo feature does not exhibit the complex sinuous structure of well known swirls such as the reiner gamma formation but does possess a bright loop and central dark lane another strong magnetic anomaly in the apollo 16 descartes region corresponds to a simple diffuse bright albedo spot on this basis we suggest that a continuum of swirl morphologies exists on the moon with the airy feature representing an intermediate or incipient swirl form

coupling ground and airborne geophysical data with upscaling techniques for regional groundwater modeling of heterogeneous aquifers case study of a sedimentary aquifer intruded by volcanic dykes in northern ireland in highly heterogeneous aquifer systems conceptualization of regional groundwater flow models frequently results in the generalization or negligence of aquifer heterogeneities both of which may result in erroneous model outputs the calculation of equivalence related to hydrogeological parameters and applied to upscaling provides a means of accounting for measurement scale information but at regional scale in this study the permo triassic lagan valley strategic aquifer in northern ireland is observed to be heterogeneous if not discontinuous due to subvertical trending low permeability tertiary dolerite dykes interpretation of ground and aerial magnetic surveys produces a deterministic solution to dyke locations by measuring relative permeabilities of both the dykes and the sedimentary host rock equivalent directional permeabilities that determine anisotropy calculated as a function of dyke density are obtained this provides parameters for larger scale equivalent blocks which can be directly imported to numerical groundwater flow models different conceptual models with different degrees of upscaling are numerically tested and results compared to regional flow observations simulation results show that the upscaled permeabilities from geophysical data allow one to properly account for the observed spatial variations of groundwater flow without requiring artificial distribution of aquifer properties it is also found that an intermediate degree of upscaling between accounting for mapped field scale dykes and accounting for one regional anisotropy value maximum upscaling provides results the closest to the observations at the regional scale

holocene vegetation history of the kotihi lagoon northwest peloponnesus greece abstract pollen diagrams are presented from two sediment cores from the area of kotihi lagoon in the northwestern peloponnesus greece radiocarbon dates indicate that the analyzed sediments accumulated during the last 7000 years six pollen assemblage zones are recognized the oldest zone middle neolithic in age is characterized by dominance of herbaceous types nap the second zone dated to the late and final neolithic shows a considerable increase in the abundance of arboreal types ap and a decrease in herbaceous taxa the third zone from the bronze age did not register any substantial change in the vegetation but the various communities changed considerably in the fourth zone from the iron age to roman period the abundance of arboreal types varied in the fifth zone medieval in age and in the sixth zone corresponding to the ottoman period arboreal pollen abundances continued to prevail during the last 3000 years human activity was the main factor influencing the vegetation in the study area

geoscience of ancient mediterranean harbours abstract although much has been written on the subject of ancient mediterranean harbours the relatively new area of harbour geoarchaeology remains dispersed in the geoscience and archaeological literature over a decade of research has amassed rich and varied datasets of anthropogenically forced coastal evolution with a remarkable number of between site analogies this new research field also shows the rich potential of geoscience to reconcile important archaeological questions no single publication however has yet drawn on these geological patterns to yield a detailed overview suitable for geoscientists and environmental archaeologists the aim of this review article is to 1 discuss how ancient harbours have come to be preserved in the geological record 2 expound the basic principles and palaeoenvironmental tools underpinning ancient harbour geoarchaeology 3 outline some of the most significant research advances made and 4 discuss a new chrono stratigraphic model applicable to harbour sequences

human influence and the changing geomorphology of mediterranean deltas and coasts over the last 6000 years from progradation to destruction phase the present geomorphology of the mediterranean s coasts is largely a product of an intricate long term relationship between nature and human societies a cradle of ancient civilisations the mediterranean has seen its shores occupied by humans since prehistory and is therefore a particularly pertinent unit of analysis the morphotectonic context and other forcing agents e g climate shaped out a highly diversified coastal morphology and generated a sediment supply regime potentially favourable to the formation of numerous open coast deltas and bay head deltas in infilled rias as sea level stabilised during the mid holocene this supply of riverine sediment has also been the key agent in mediating human occupation of the mediterranean s clastic coasts expressions of this relationship have been extensively archived in clastic coastal deposits including base level deltaic and estuarine sedimentary sinks which comprise records to explore the interactions between geosystems and the human environment the stratigraphic sequences in these coastal sedimentary archives comprise in many places a clearly identified anthropogenic signature notably in ancient harbours some of which underwent extremely rapid silting up due to massive sediment sourcing generated by new agricultural practices from the neolithic onwards increasing human influence especially over the last 3000 years has been in turn an important driver of changes in sediment supply strongly modulating deltaic development pulses of sediment supply from catchments rendered vulnerable by human perturbations during the roman period resulted in a new cycle of inception of many other deltas and in rapid delta growth e g the ebro the po the arno and the ombrone another progradation dynamic during the little ice age at a time of strong rural population growth river discharge increases technological developments and urbanisation further consolidated delta growth understanding the life cycle of these deltas since their initial formation is in turn key to unravelling the relative role of natural and anthropogenic forcing agents rapid climate changes are deemed to have contributed through both the stripping of landscapes rendered fragile by human activities and active fluvial sediment transport to the coast but disentangling climate change effects from human impacts in the mediterranean remains a challenge the patterns of subsequent deltaic growth and delta morphodynamics reflect adaptations to pulsed sediment supply river discharge variations the microtidal fetch limited context of the mediterranean and direct engineering interventions the progradation dynamic of the roman period and little ice age contrasts markedly with the situation of common coastal destabilisation over the last two centuries particularly well documented for the last 50 years this period has been characterised by reduced sediment flux to base level geosystems due to catchment reforestation retenion within reservoirs fluvial regulation and dredging resulting in the erosion of deltas and barrier lagoon and beach dune systems large stretches of shoreline and narrow coastal plains have been massively engineered for coastal defence and protection against erosion but also for the construction of marinas leisure harbours and artificial beaches resulting in the emergence of veritable artificial seafronts these interventions have collectively and progressively raised societies to a pervasive and overarching position in the geomorphic stability instability of the mediterranean s coasts a situation that will be exacerbated by pressures from sea level rise paving the way for rampant coastal erosion and delta destruction

discovery of a basaltic asteroid in the outer main belt visible and near infrared spectroscopic observations of the asteroid 1459 magnya indicate that it has a basaltic surface magnya is at 3 15 astronomical units au from the sun and has no known dynamical link to any family to any nearby large asteroid or to asteroid 4 vesta at 2 36 au which is the only other known large basaltic asteroid we show that the region of the belt around magnya is densely filled by mean motion resonances generating slow orbital diffusion processes and providing a potential mechanism for removing other basaltic fragments that may have been created on the same parent body as magnya magnya may represent a rare surviving fragment from a larger differentiated planetesimal that was disrupted long ago

surface lithologic heterogeneity of asteroid 4 vesta abstract high precision spectrophotometry of 4 vesta the third largest asteroid was used to establish the surface composition of this body and to investigate mineralogical variations across its surface the average surface of vesta is analogous to howardite and or polymict eucrite assemblages regolith derived members of the hed meteorite suite which consist of a eucrite matrix containing differing amounts of a diogenite component color and or spectral changes which exhibit a consistent relationship to rotational phasing are evident in 16 of 18 studies of vesta dating back to 1929 including the present work after elimination of possible sources of spurious spectral or color changes it is concluded that these variations arise from hemispheric variations in surface materials and hence provide a means of spatially resolving subhemispheric compositional units on the surface of vesta the background surface of vesta is a relatively dark howardite or polymict eucrite pyroxene plagioclase assemblage with several compositionally distinct bright regions clustered in one hemisphere viewed around the maximum in vesta s lightcurve these include what appears to be an olivine bearing unit suggested name leslie formation located near vesta s equator which probably represents an impact basin and or its associated ejecta that penetrated through the basaltic crust other high albedo compositional units including an apparently low calcium eucrite region and several diogenite pyroxenite regions at least one located near the southern pole may be smaller shallower impact basins by analogy to the eucrite meteorites which represent surface flows or shallow intrusions and which constitute the major component of the regolith derived howardites and polymict eucrites we conclude that the howardite polymict eucrite units represent a regolith gardened original surface of vesta it is probable that the low albedo of the background surface on vesta is due to an age related darkening effect similar to that inferred from the galileo images of gaspra and ida this mechanism is consistent with the correlation of absorption feature intensity with the lightcurve vesta appears to have an old eucritic surface darkened with age and represented among the meteorites by the regolith derived howardites and polymict eucrites on which several impacts on one hemisphere have exposed fresher brighter diogenite and olivine bearing material based on qualitative analysis of the mineralogical variations as a function of rotation a generalized lithologic map of vesta was produced there is reasonable control on the longitude of lithologic features but little control on their latitudes except where specifically noted in producing this map discrete circular features were used on the plausible assumption that impacts have been the most important geologic process on this surface for most of the age of the solar system the shape of the features has thus been assumed rather than derived and is subject to future revision as data improve

late glacial to mid holocene palaeoclimate development of southern greece inferred from the sediment sequence of lake stymphalia ne peloponnese abstract the sedimentary sequence of lake stymphalia ne peloponnese for the first time sheds light on the palaeoclimate development of southern greece from 15 to 5 ka bp new geochemical data based on high resolution x ray fluorescence scanning provide in situ and continuous analysis of predefined element suites on split core surfaces variations of elements over time were assessed constructing correlation matrices based on the calculation of pearson correlation coefficients the element suite includes al si k ca ti mn fe zn rb sr and zr a major result includes that changes in element behaviour are related to hydrological changes in the catchment precipitation lake level status and evaporation insolation solar activity and are ultimately driven by climate major trends shifts in elemental ratios correspond to the climate development in the eastern mediterranean region based on correlation of rb sr reflecting wet dry climates with foraminiferal proxies of marine core lc21 from the southern aegean sea and the stable oxygen isotope record of soreq cave israel the bolling allerod the younger dryas and the 8 2 ka cold event were identified

dawn completes its mission at 4 vesta the dawn mission was designed to test our hypothesis about the origin and evolution of the early solar system by visiting the largest differentiated basaltic asteroid 4 vesta believed to be a survivor from the earliest times of rocky body formation observations from orbit show that vesta is the parent body of the howardite eucrite diogenite meteorites vesta has an iron core and a eucritic diogenitic crust its surface is characterized by abundant impact craters but with no evident volcanic features it has two ancient impact basins in the southern hemisphere that are associated with circum planetary troughs the northern hemisphere is the more heavily cratered and contains the oldest terrains the surface of vesta is diverse with north south and east west dichotomies in the eucrite to diogenite ratio its surface contains both very bright and very dark material and its color varies strongly from region to region both the mineralogical and the elemental compositions agree with that expected for the hed parent body significant oh or h may be present in the upper crust and the presence of pits in fresh craters is consistent with the devolatilization of the surface after a collision either brought to or tapped a source of water on vesta the presence of dark material on the surface of vesta suggests efficient transport pathways for organic material and the mixing of the dark material with the more pristine pyroxene explains the varying albedo across the surface vesta has proven to be a reliable witness to the formation of the solar system

space weathering on airless bodies resolving a mystery with lunar samples using new techniques to examine the products of space weathering of lunar soils we demonstrate that nanophase reduced iron npfe0 is produced on the surface of grains by a combination of vapor deposition and irradiation effects the optical properties of soils both measured and modeled are shown to be highly dependent on the cumulative amount of npfe0 which varies with different starting materials and the energetics of different parts of the solar system the measured properties of intermediate albedo asteroids the abundant s type asteroids in particular are shown to directly mimic the effects predicted for small amounts of npfe0 on grains of an ordinary chondrite regolith this measurement and characterization of space weathering products seems to remove a final obstacle hindering a link between the abundant ordinary chondrite meteorites and common asteroids

impact excavation on asteroid 4 vesta hubble space telescope results hubble space telescope images of asteroid 4 vesta obtained during the favorable 1996 apparition show an impact crater 460 kilometers in diameter near the south pole color measurements within the 13 kilometer deep crater are consistent with excavation deep into a high calcium pyroxene rich crust or olivine upper mantle about 1 percent of vesta was excavated by the crater formation event a volume sufficient to account for the family of small vesta like asteroids that extends to dynamical source regions for meteorites this crater may be the site of origin for the howardite eucrite and diogenite classes of basaltic achondrite meteorites

first disk resolved spectroscopy of 4 vesta abstract vesta the second largest main belt asteroid will be the first to be explored in 2011 by nasa s dawn mission it is a dry likely differentiated body with spectrum suggesting that is has been resurfaced by basaltic lava flows not too different from the lunar maria here we present the first disk resolved spectroscopic observations of an asteroid from the ground we observed 4 vesta with the eso vlt adaptive optics equipped integral field near infrared spectrograph sinfoni as part of its science verification campaign the highest spatial resolution of 90 km on vesta s surface was obtained during excellent seeing conditions 0 5 in october 2004 we observe spectral variations across vesta surface that can be interpreted as variations of either the pyroxene composition or the effect of surface aging we compare vesta s 2 m absorption band to that of howardite eucrite diogenite hed meteorites that are thought to originate from vesta and establish particular links between specific regions and hed subclasses the overall composition is found to be mostly compatible with howardite meteorites although a small area around 180 e longitude could be attributed to a diogenite rich spot we finally focus our spectral analysis on the characteristics of vesta s bright and dark regions as seen from hubble space telescope s visible and keck ii s near infrared images

a review of palaeoclimates and palaeoenvironments in the levant and eastern mediterranean from 25 000 to 5000 years bp setting the environmental background for the evolution of human civilisation abstract the southern levant has a long history of human habitation and it has been previously suggested that climatic changes during the late pleistocene holocene stimulated changes in human behaviour and society in order to evaluate such linkages it is necessary to have a detailed understanding of the climate record we have conducted an extensive and up to date review of terrestrial and marine climatic conditions in the levant and eastern mediterranean during the last 25 000 years we firstly present data from general circulation models gcms simulating the climate for the last glacial maximum lgm and evaluate the output of the model by reference to geological climate proxy data we consider the types of climate data available from different environments and proxies and then present the spatial climatic picture for key climatic events this exercise suggests that the major northern hemisphere climatic fluctuations of the last 25 000 years are recorded in the eastern mediterranean and levantine region however this review also highlights problems and inadequacies with the existing data

paleoenvironmental changes since 3000 bc in the coastal marsh of vravron attica se greece abstract the coastal area of the vravron bay in the vicinity of the homonym archaeological site is a marshy plain located on the eastern part of the attica peninsula eastern greece in order to provide evidence for palaeoenvironmental changes and landscape evolution of the area detailed micropaleontological palynological and sedimentological analyses have been conducted at the underlying late holocene coastal deposits the recovered sediments lithostratigraphic units a d represent a continuous record of the environmental history of the area since the early bronze age covering all subsequent historical periods the base of the recovered deposits is older than the 3rd millennium bc until late medieval times the studied sequence contains plenty evidence for the existence of the natural port reported from the mycenaean lithostratigraphic unit a that infilled after repeated flooding events during the classic period lithostratigraphic unit b and gradually developed into a shallower marine environment lithostratigraphic unit c in the uppermost part of the sequence lithostratigraphic unit d a transition towards brackish environment with intense fresh water input is featured around 1540 ad signs of human agricultural activities in vravron appear since 3000 bc early bronze age and are linked to the history of inhabitation in the area

late quaternary alluviation and soil formation in the southern argolid its history causes and archaeological implications in the context of an archaeological survey of the southern argolid greece studies have been carried out to elucidate the evolution of the landscape since its earliest known human occupation about 50 000 years ago one of these studies was a detailed geological mapping of the late quaternary alluvium and soils in the area dated by means of thorium uranium disequilibria archaeological finds and historical information seven periods of alluviation were identified each of short duration relative to long intervening periods of stability and soil formation the three earliest alluvial phases falling before and during the last glacial interval range from about 330 000 to 32 000 years in age no alluviation accompanied the last glacial maximum around 20 000 years ago in fact a stable landscape persisted until about 4500 years ago when debris flows and widespread aggradation in the valleys resulted from major slope destabilization and soil erosion probably as a result of extensive land clearance in the early bronze age a subsequent stable period lasted through the many upheavals of the later bronze age the dark ages and the early historical period it came to an end with a brief phase of alluviation between about 300 and 50 bc stability returned through the late roman period notwithstanding considerable expansion of the settled area another period of destabilization this one marked by debris flows and hence major soil erosion is poorly fixed in time but probably coincides with expanded maquis clearance accompanying the resettlement of the area around ad 1000 subsequent events of soil erosion and aggradation vary in nature and timing from one drainage to the next and in some areas continue today nature and chronology of the soil forming and alluviation events show that simple correlations with climatic events do not suffice to explain them for the latter ones past about 2500 bc human activity seems to be the dominant cause but once again the relation between cause and effect is not straightforward land clearing or neglect of soil conservation efforts during economic downturns appear to have a more devastating effect upon the landscape than do intensive land use or total land abandonment

historical and pre historical tsunamis in the mediterranean and its connected seas geological signatures generation mechanisms and coastal impacts abstract the origin of tsunamis in the mediterranean region and its connected seas including the marmara sea the black sea and the sw iberian margin in the ne atlantic ocean is reviewed within the geological and seismotectonic settings of the region a variety of historical documentary sources combined with evidence from onshore and offshore geological signatures geomorphological imprints observations from selected coastal archeological sites as well as instrumental records eyewitnesses accounts and pictorial material clearly indicate that tsunami sources both seismic and non seismic e g volcanism landslides can be found in all the seas of the region with a variable tsunamigenic potential local regional and basin wide tsunamis have been documented an improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented from west to east the most important tsunamigenic zones are situated offshore sw iberia in the north algerian margin in the tyrrhenian calabria and messina straits in the western and eastern segments of the hellenic arc in the corinth gulf of central greece in the levantine sea offshore the dead sea transform fault and in the eastern side of the marmara sea important historical examples including destructive tsunamis associated with large earthquakes are presented the mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency 1 96 years is observed in the east mediterranean basin for most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co seismic slip by earthquake triggered submarine landslides or by a combination of both mechanisms in pre historical times submarine volcanic eruptions i e caldera collapse massive pyroclastic flows volcanogenic landslides and large submarine landslides caused important tsunamis although little is known about their source mechanisms we conclude that further investigation of the tsunami generation mechanisms is of primary importance in the mediterranean region inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent well documented aseismic landslide tsunamis e g 1963 corinth gulf 1979 cote d azur 1999 izmit bay 2002 stromboli volcano since the tsunami generation mechanisms are controlled by a variety of factors and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action future interdisciplinary research efforts on past tsunamis are needed

photometric mapping of asteroid 4 vesta s southern hemisphere with hubble space telescope abstract we present the surface mapping of the southern hemisphere of asteroid 4 vesta obtained from hubble space telescope hst from 105 images of vesta through four filters in the wavelengths best to characterize the 1 m pyroxene band we constructed albedo and color ratio maps of vesta these new maps cover latitudes 50 to 20 the southern hemisphere of vesta displays more diverse albedo and color features than the northern hemisphere with about 15 new albedo and color features identified the overall longitudinal albedo and color variations in the southern hemisphere are comparable with that of the northern hemisphere with a range of about 20 and 10 respectively the eastern hemisphere is brighter and displays more diogenitic minerals than the western hemisphere correlations between 1 m band depth and band width as well as between 1 m band depth and albedo are present on a global scale attributed to pyroxene composition variations the lack of correlations between albedo and the spectral slope indicates the absence of globalized space weathering the lack of a global correlation between 1 m band depth and topography suggests that the surface composition of vesta is not completely controlled by a single impact the distribution of compositional variation on vesta suggests a possible large impact basin evidence of space weathering is found in regions including the bright rim of the south pole crater where the steepest gravitational slope on vesta is and a dark area near a gravitationally flat area we propose to divide the surface of vesta into six geological units different from the background according to their 1 m absorption features and spectral slopes including two eucrite rich units a low ca eucrite unit a diogenite rich unit a space weathered unit and a freshly exposed unit no evidence of olivine rich area is present in these data

a late holocene record of environmental changes from kotihi lagoon elis northwest peloponnesus greece the late holocene instability of the coastline of elis was investigated using two boreholes three evolutionary stages are distinguished a from earlier than 7000 to 3810 cal bp there was a static coastline and predominantly lagoon floor sediments accumulated b from 3810 to 1400 cal bp the rate of sedimentation was higher than the rate of relative sea level change possibly because of the proximity of the mouth of the peneus river and predominantly fluvial sediments accumulated c from 1400 cal bp to present time landward migration of the coast and the re establishment of lagoonal facies was probably the result of the avulsion of the peneus river from 150 cal bp until present the rate of sedimentation in lagoon area was high about 5 2 mm a

speleothem evidence for late holocene climate variability and floods in southern greece abstract we present stable isotope data 18o 13c from a detrital rich stalagmite from kapsia cave the peloponnese greece the cave is rich in archeological remains and there are reasons to believe that flooding of the cave has directly affected humans using the cave using a combination of u th and 14c dating to constrain a site specific correction factor for 232th 238u detrital molar ratio a linear age model was constructed the age model shows that the stalagmite grew during the period from ca 950 bc to ca ad 830 the stable oxygen record from kapsia indicates cyclical changes of close to 500 yr in precipitation amount with rapid shifts towards wetter conditions followed by slowly developing aridity superimposed on this signal wetter conditions are inferred around 850 700 500 and 400 100 bc and around ad 160 300 and ad 770 and driest conditions are inferred to have occurred around 450 bc ad 100 150 and ad 650 detrital horizons in the stalagmite indicate that three major floods took place in the cave at 500 bc 70 bc and ad 450 the stable carbon isotope record reflects changes in biological activity being a result of both climate and human activities

the distribution of basaltic asteroids in the main belt abstract we present the observational results of a survey designed to target and detect asteroids whose photometric colors are similar to those of vesta family members and thus may be considered as candidates for having a basaltic composition fifty basaltic candidates were selected with orbital elements that lie outside of the vesta dynamical family optical and near infrared spectra were used to assign a taxonomic type to 11 of the 50 candidates ten of these were spectroscopically confirmed as v type asteroids suggesting that most of the candidates are basaltic and can be used to constrain the distribution of basaltic material in the main belt using our catalog of v type candidates and the success rate of the survey we calculate unbiased size frequency and semi major axis distributions of v type asteroids these distributions in addition to an estimate for the total mass of basaltic material suggest that vesta was the predominant contributor to the basaltic asteroid inventory of the main belt however scattered planetesimals from the inner solar system a 2 0 au and other partially fully differentiated bodies likely contributed to this inventory in particular we infer the presence of basaltic fragments in the vicinity of asteroid 15 eunomia which may be derived from a differentiated parent body in the middle main belt 2 5 a 2 8 we find no asteroidal evidence for a large number of previously undiscovered basaltic asteroids which agrees with previous theories suggesting that basaltic fragments from the 100 differentiated parent bodies represented in meteorite collections have been battered to bits burbine t h meibom a binzel r p 1996 meteorit planet sci 31 607 620

relative sea level changes and regional tectonic evolution of seven coastal areas in nw greece since the mid holocene abstract this study presents relative sea level rsl curves for seven coastal areas in akarnania and the northwestern peloponnese nw greece since the mid holocene rsl fluctuations are deduced from 48 14c ams dated sedimentological sea level markers from 27 vibracores drilled in near coast geological archives as well as from six geoarchaeological sea level indicators of known ages seven palaeo sea level curves including uncertainty bands are reconstructed for a coastal zone spanning a distance of 150 km considerable intra regional differences in sea level evolution exist these differences are mainly due to tectonic reasons in general rsl in northwestern greece has never been higher than today rates of local sea level rise were highest until 5500 5000 cal bc up to 12 3 m ka and lowest during 4000 500 cal bc 0 2 1 4 m ka during the past 2500 or so years rsl has accelerated anew 0 7 2 7 m ka calculating differences between local mean sea level curves provides quantitative information on intra regional differences of tectonic activity the coastal plains of palairos and elis show signs of uplift whereas the mytikas and boukka plains are strongly subsiding compared to other areas of the eastern mediterranean northwestern greece has been subject to significant net long term subsidence regional tectonic events rtes were detected for the time around 4000 2500 500 and 250 cal bc as well as around 250 and 1250 cal ad rtes are characterized by changes of uplift subsidence rates or by the redirection of local tectonic movements the question if some of the rtes were of a supra regional nature is still open from a geodynamic point of view the results presented show that akarnania s southwestern fringe is being downwarped while the tectonic block as a whole is moving towards the southwest strongest subsidence rates are observed for central akarnania at akarnania s fringes subsidence is reduced by the influence of strong uplift of adjacent areas such as around preveza and the northern peloponnese

poseidon s horses plate tectonics and earthquake storms in the late bronze age aegean and eastern mediterranean abstract in light of the accumulated evidence now published the oft denigrated suggestion that major earthquakes took place in the aegean and eastern mediterranean areas during the late 13th and early 12th centuries bc must be reconsidered a new study of earthquakes occurring in the aegean and eastern mediterranean region during the 20th century utilizing data recorded since the invention of seismic tracking devices shows that this area is criss crossed with major fault lines and that numerous temblors of magnitude 6 5 enough to destroy modern buildings let alone those of antiquity occur frequently it can be demonstrated that such major earthquakes often occur in groups known as sequences or storms in which one large quake is followed days months or even years later by others elsewhere on the now weakened fault line when a map of the areas in the aegean and eastern mediterranean region affected i e shaken by 20th centuryad earthquakes of magnitude 6 5 and greater and with an intensity of vii or greater is overlaid on robert drews map of sites destroyed in these same regions during the so called catastrophe near the end of the late bronze age it is readily apparent that virtually all of these lba sites lie within the affected high shaking areas while the evidence is not conclusive based on these new data we would suggest that an earthquake storm may have occurred in the late bronze age aegean and eastern mediterranean during the years 1225 1175bc this storm may have interacted with the other forces at work in these areas c 1200bc and merits consideration by archaeologists and prehistorians

contemporaneous alkaline and tholeiitic magmatism in the ponta grossa arch parana etendeka magmatic province constraints from u pb zircon baddeleyite and 40ar 39ar phlogopite dating of the jose fernandes gabbro and mafic dykes abstract we report the first high precision id tims u pb baddeleyite zircon and 40ar 39ar step heating phlogopite age data for diabase and lamprophyre dykes and a mafic intrusion jose fernandes gabbro located within the ponta grossa arch brazil in order to constrain the temporal evolution between early cretaceous tholeiitic and alkaline magmatism of the parana etendeka magmatic province u pb dates from chemically abraded zircon data yielded the best estimate for the emplacement ages of a high ti p sr basaltic dyke 133 9 0 2 ma a dyke with basaltic andesite composition 133 4 0 2 ma and the jose fernandes gabbro 134 5 0 1 ma a 40ar 39ar phlogopite step heating age of 133 7 0 1 ma from a lamprophyre dyke is identical within error to the u pb age of the diabase dykes indicating that tholeiitic and alkaline magmatism were coeval in the ponta grossa arch although nearly all analysed fractions are concordant and show low analytical uncertainties 0 3 0 9 ma for baddeleyite 0 1 0 4 ma for zircon 2 pb loss is observed in all baddeleyite fractions and in some initial zircon fractions not submitted to the most extreme chemical abrasion treatment the resulting age spread may reflect intense and continued magmatic activity in the ponta grossa arch

optical space weathering on vesta radiative transfer models and dawn observations abstract exposure to ion and micrometeoroid bombardment in the space environment causes physical and chemical changes in the surface of an airless planetary body these changes called space weathering can strongly influence a surface s optical characteristics and hence complicate interpretation of composition from reflectance spectroscopy prior work using data from the dawn spacecraft pieters c m et al 2012 nature 491 79 82 found that accumulation of nanophase metallic iron npfe0 which is a key space weathering product on the moon does not appear to be important on vesta and instead regolith evolution is dominated by mixing with carbonaceous chondrite cc material delivered by impacts in order to gain further insight into the nature of space weathering on vesta we constructed model reflectance spectra using hapke s radiative transfer theory and used them as an aid to understanding multispectral observations obtained by dawn s framing cameras fc the model spectra for a howardite mineral assemblage include both the effects of npfe0 and that of a mixed cc component we found that a plot of the 438 nm 555 nm ratio vs the 555 nm reflectance for the model spectra helps to separate the effects of lunar style space weathering lssw from those of cc mixing we then constructed ratio reflectance pixel scatterplots using fc images for four areas of contrasting composition a eucritic area at vibidia crater a diogenitic area near antonia crater olivine bearing material within bellicia crater and a light mantle unit referred to as an orange patch in some previous studies based on steep spectral slope in the visible northeast of oppia crater in these four cases the observed spectral trends are those expected from cc mixing with no evidence for weathering dominated by production of npfe0 in order to survey a wider range of surfaces we also defined a spectral parameter that is a function of the change in 438 nm 555 nm ratio and the 555 nm reflectance between fresh and mature surfaces permitting the spectral change to be classified as lssw like or cc mixing like when applied to 21 fresh and mature fc spectral pairs it was found that none have changes consistent with lssw we discuss vesta s lack of lssw in relation to the possible agents of space weathering the effects of physical and compositional differences among asteroid surfaces and the possible role of magnetic shielding from the solar wind

solar wind as the origin of rapid reddening of asteroid surfaces a comparison of the laboratory reflectance spectra of meteorites with observations of asteroids revealed that the latter are much redder with the spectral difference explained by space weathering though the actual processes and timescales involved have remained controversial a recent study of young asteroid families concluded that they suffered only minimal space weathering here we report additional observations of those families revealing that space weathering must be a very rapid process the final colour of a silicate rich asteroid is acquired shortly after its birth within 10 6 years of undergoing a catastrophic collision this rapid timescale favours solar wind implantation as the main mechanism of space weathering as laboratory experiments have shown that it is the most rapid of several competing processes we further demonstrate the necessity to take account of composition when evaluating weathering effectiveness as both laboratory and asteroid data show an apparent dependence of weathering on olivine abundance the rapid colour change that we find implies that colour trends seen among asteroids are most probably due to compositional or surface particle size properties rather than to different relative ages apparently fresh surfaces most frequently seen among small near earth asteroids may be the result of tidal shaking that rejuvenates their surfaces during planetary encounters

an assessment of human versus climatic impacts on holocene soil erosion in ne peloponnese greece soil erosion is a natural geomorphological process which can be triggered by both natural climate tectonics or both and anthropogenic e g agriculture perturbation of the ecosystem evidence has accrued that the holocene climate experienced large fluctuations in amplitude and suggestions of human impact on the ecosystem provided by the neolithic revolution dating back to the early holocene have been made the question of whether man or climate was the dominant factor responsible for holocene soil erosion remains unresolved to resolve the reasons for holocene sediment redistribution high resolution chronometric data on sediments derived from colluvial and alluvial archives from southern greece were obtained and combined with available archaeological and paleoclimatic data from the eastern mediterranean these data show a significant correlation between sedimentation rates and settlement history climatic fluctuations are only weakly correlated with sedimentation history the results show high sedimentation rates during the early neolithic 7th millennium bc in southern greece suggesting that holocene soil erosion was triggered by human activity and then amplified by enhanced precipitation this would explain the high sedimentation rates during the early neolithic in connection with enhanced precipitation in the eastern mediterranean which continued until the mid holocene

the holocene sea level story since 7500 bp lessons from the eastern mediterranean the black and the azov seas abstract this paper addresses the obvious controversy between the so far published sea level curves of the black sea and the mediterranean it starts with a discussion of the methods of reconstructing sea level curves the evaluation of sea level indicators and the application of the radiocarbon dating method at least since 7500 bp when the black sea and the mediterranean were connected both water bodies must have reacted synchronously on glacio eustatic changes it is documented that none of the mediterranean sea level curves shows the major wiggles postulated for the black sea which are supposed to reflect trans and regression cycles the very shallow bathymetric condition of the azov sea and the northern black sea should have led to considerable and traceable shoreline displacements there is neither archaeological nor historical evidence of mid and late holocene regressions of several meters the tectonic setting of the black and azov seas implicates that the tectonic signal often overrides the eustatic one therefore only local sea level curves can be established in this paper based on vibracores a locally valid sea level curve for the taman peninsula is demonstrated layers of paralic peat were used as sea level indicators and for 14 c dating the shape of this curve follows the one known from the mediterranean this study also revealed that the present peninsula of taman evolved out of a former archipelago

vestan lithologies mapped by the visual and infrared spectrometer on dawn we present global lithological maps of the vestan surface based on dawn mission s visible infrared vir spectrometer acquisitions with a spatial sampling of 200 m the maps confirm the results obtained with the data set acquired by vir with a spatial sampling of 700 m that the reflectance spectra of vesta s surface are dominated by pyroxene absorptions that can be interpreted within the context of the distribution of howardites eucrites and diogenites heds the maps also partially agree with the ground and hubble space telescope observations they confirm the background surface being an assemblage of howardite or polymict eucrite as well as the location of a diogenitic rich spot however there is no evidence of extended olivine rich regions in the equatorial latitudes diogenite is revealed on the rheasilvia basin floor indicating that material of the lower crust mantle was exposed vir also detected diogenites along the scarp of matronalia rupes and the rims of severina and a nearby unnamed crater and as ejecta of antonia crater the diogenite distribution is fully consistent with petrological constraints although the mapped distribution does not provide unambiguous constraints it favors the hypothesis of a magma ocean

modal mineralogy of the surface of vesta evidence for ubiquitous olivine and identification of meteorite analogue abstract the observations of the surface of 4 vesta by the visible and infrared mapping spectrometer vir onboard the dawn spacecraft reveals that its composition is dominated by pyroxenes with olivine in very localized spots to derive new constraints on the surface composition of the asteroid we apply a scattering model to vir reflectance spectra the model is first calibrated by performing a non linear deconvolution of laboratory spectra of mineral mixtures and howardite eucrite diogenite hed meteorites abundance estimates of minerals are accurate to within 15 25 for the analyzed samples while the estimated particle sizes are within the intervals of actual sizes grain size effects complicate spectral deconvolution and estimation of modal abundances of samples both hed and mineral mixtures that contain olivine the magnesium rich olivine detection threshold is 10 20 for large grain sizes 100s m and several 10s for small grain sizes

well productivity in the ponta grossa dike swarm brazil an integrated study with magnetic data inversion and clustering analysis of model solutions abstract dike swarms are mega structures observed in different geological contexts which may affect groundwater flow systems these structures are well recognizable from airborne magnetic however it is difficult to obtain quantitative information about distribution and mean properties of dikes that generate the observed magnetic anomalies this work presents a procedure to perform magnetic data inversion along profiles transecting the ponta grossa dike swarm pgds and determine its mean properties with application of cluster analysis to obtained solutions next the mean model solutions are correlated with a regional database of borehole productivity suggesting that more productive wells are found close to a group of shallow dikes of the pdgs in southeastern brazil for the area mainly composed by sedimentary rocks the wells situated over shallow dikes show higher values of specific capacity by a factor of 14 5 than those not close to a dike in the same domain for the area mainly composed by granitic rocks the productivity of wells over dikes is still higher a factor of 4 3 higher than those with no dikes a conceptual model is presented to explain the higher productivity of wells close to the dikes as resulting from fracturing on host rock caused by dikes emplacement only a group of shallow dikes seems to be associated with more productive wells

tracking mid to late holocene depositional environments by applying sedimentological palaeontological and geochemical proxies amvrakikos coastal lagoon sediments western greece mediterranean sea abstract this study presents sedimentological palaeontological geochemical mineralogical and organic petrography data from a 30 m deep core representing a mid to late holocene lagoonal depositional environment of a coastal area of amvrakikos gulf western greece three horizons were dated using 14c the sedimentological palaeontological and geochemical interpretations of the lagoonal sediments reveal three major lithological units deposited between around 5200 and 1600 bp the upper lithological unit extended to a depth of 11 20 m the middle from 11 20 to 21 30 m and the lower one from 21 30 to 30 00 m a mean rate of sedimentation of 5 7 mm y and a maximum rate of 12 6 mm y were estimated the mineralogical analysis and the magnetic susceptibility of the core points to a constant sediment source supply the mid to late holocene depositional environment mainly reflects inundation by the braid plain of the arachthos and secondarily by the louros river the reconstruction of the depositional environments corresponds to a shallow marine and deltaic brackish lagoon and specifically to an environment proximal to river supply the high rates of sedimentation as well as the interpretation of depositional environments indicate that the coastal sedimentological processes during the mid to late holocene were mainly controlled by the progradation of river deltas moreover the geochemical proxies the recovered molluscs and the microfauna as well as the organic petrography analyses indicate periods of dysoxic and hypoxic conditions these holocene dysoxic and hypoxic events indicate that the recent dystrophic crises in the amvrakikos gulf are not only the result of human activities but also the contribution of natural processes

the nisi fault as a key structure for understanding the active deformation of the nw peloponnese greece abstract the previously unknown nisi fault in nw peloponnese was ruptured during the 2008 movri mountain earthquake attaining a maximum offset of 25 cm the fault is interpreted as a branch of a flower structure above a blind strike slip fault we investigate the nisi fault seismotectonic evolution using morphotectonic analysis in order to determine whether the landscape is affected by tectonic forcing and paleoseismology to determine earthquake recurrence interval and fault slip rates we applied several geomorphic indices such as the asymmetry factor af the stream length gradient index sl the valley floor width to valley height ratio vf the mountain front sinuosity smf the drainage basin shape bs and the hypsometric curve hc in four large drainage basins of the study area the results show that fault related vertical motions and the associated tilting influenced the drainage geometry and the landscape development values of stream gradient indices sl are relatively high close to the fault trace mountain front sinuosity smf mean values along the fault zones range from 1 12 to 1 23 valley floor width to valley height ratios vf mean values along the studied fault range between 0 21 and 2 50 drainage basin shape bs mean values along the fault range from 1 04 to 3 72 lateral fault growth was likely achieved by propagation primarily towards north northwestward the paleoseismic history of the fault investigated by a trench and 14c dating of seven samples indicates two morphogenic earthquakes in the last 1 kyr therefore we suggest that the nisi fault displays a slip rate on the order of 1 mm yr and a recurrence interval ranging between 300 and 600 years from a seismotectonic point of view the fault is classified as high activity rate with abundant but discontinuous geomorphic evidence of its activity other similar faults affecting the western peloponnese can be envisaged with a similar procedure additionally the seismic history and surface expression of the nisi fault resembles other faults of similar length in greece and italy particularly a crucial issue in terms of seismic risk management is that neotectonic analysis has to be envisaged carefully on short in length faults since these faults can be possibly related to strong earthquakes

a late holocene record of environmental changes from the aliki lagoon egion north peloponnesus greece abstract aliki lagoon is a small lagoon located on the micro tidal south coast of the gulf of corinth greece the sediments of the lagoon recovered in three cores provide a record of late holocene environmental change including tectonic subsidence tsunami layers and change in local vegetation and sedimentation four periods of rapid environmental changes were identified over a 5000 yr long record these date from about 4700 3000 2500 and 2000 yr bp each change is linked to activity on the egion fault a deepening of the lagoonal bottom and a rise in relative sea level six tsunami events are recorded and have been caused by earthquakes on the egion fault three events 4700 3000 and 2500 bp eliki fault 2350 40 yr bp and two more distal fault ruptures the vegetation history and pollen zones are similar to those recognised by jahns vegetation hist archaebot 2 1993 187 on the argive plain 100 km southeast of the lagoon five successive sedimentological configurations are established in relation to the time frame provided by the tectonic activity 1 crevasse splay 2 fresh to brackish water marsh 3 and 4 brackish to hypersaline blind lagoon and 5 brackish to hypersaline blind lagoon or brackish open lagoon

high resolution environmental reconstruction in sw peloponnese greece covering the last c 6000 years evidence from agios floros fen messenian plain a paleolimnological record from the central messenian plain southwestern peloponnese southern greece indicates rapid changes in the water level and chemistry of a transient lake on the flanks of the taygetos mountains during the last c 6000 years the analyses are based on diatoms as well as carbon and nitrogen isotopes from bulk sediments in a 7 5 m long sediment core retrieved from the drained fen of agios floros at the northern banks of the ancient river pamisos the sequence consists of fen peat in the uppermost section underlain by lacustrine sediments which are punctuated by two layers of clay with diatomaceous silt bands high accumulation rate is recorded in the oldest part of the section up to 23 mm yr particularly during two decadal long periods centered at c 5700 and c 5300 cal bp the diatom record reveals pronounced peaks in the planktonic taxon cyclotella distinguenda which correspond to the laminated sequences reflecting the rapid development of a deep lake with an open water

observed spectral properties of near earth objects results for population distribution source regions and space weathering processes abstract we present new visible and near infrared spectroscopic measurements for 252 near earth neo and mars crossing mc objects observed from 1994 through 2002 as a complement to the small main belt asteroid spectroscopic survey smass http smass mit edu combined with previously published smass results we have an internally consistent data set of more than 400 of these objects for investigating trends related to size orbits and dynamical history these data also provide the basis for producing a bias corrected estimate for the total neo population stuart and binzel 2004 icarus 170 295 311 we find 25 of the 26 bus 1999 phd thesis taxonomic types are represented with nearly 90 of the objects falling within the broad s q x and c complexes rare a and e types are more common in the mc than neo population about 5 compared to 3 orbits in terms of possible space weathering effects we see a size dependent transition from ordinary chondrite like q type objects to s type asteroids over the size range of 0 1 to 5 km where the transition is effectively complete at 5 km a match between the average surface age of 5 km asteroids and the rate of space weathering could constrain models for both processes however space weathering may proceed at a very rapid rate compared with collisional timescales in this case the presence or absence of a regolith may be the determining factor for whether or not an object appears space weathered thus 0 1 to 5 km appears to be a critical size range for understanding the processes timescales and conditions under which a regolith conducive to space weathering is generated retained and refreshed

crustal deformation in the central ionian islands greece results from dgps and dinsar analyses 1995 2006 abstract ground deformation studies based on differential gps dgps and differential interferometric sar dinsar analyses have been conducted in the seismically active area of the central ionian islands local gps networks were installed in cephallonia 2001 and zakynthos 2005 the cephallonian network has been remeasured five times and zakynthos once as of july 2006 the studies have yielded detailed information regarding both local and regional deformations that are occurring in the area for lefkas island dinsar analysis march to september 2003 revealed 56 mm of uplift in the central and western parts and is attributed to the august 2003 earthquake mw 6 3 that occurred offshore to the west synthetic dinsar modelling of the magnitude and extent of deformation is consistent with the seismologically deduced parameters for the ruptured segment along the lefkas transform fault subsidence for cephallonia island dinsar analysis 1995 to 1998 indicated ground deformation up to 28 mm located in small sections of the island further interferometric analysis for the period 2003 to 2004 encompassing the occurrence of the lefkas earthquake in august 2003 indicated 28 mm of uplift in the northern part while during the next two years 2004 to 2005 further uplift of at least 56 mm had taken place at the western and northern part of the island dgps measurements for the period 2001 to 2006 revealed a clockwise rotation of the island with respect to a centrally located station on aenos mt the horizontal component of deformation generally ranged from 6 to 34 mm with the largest values at the western and northern parts of the island considering the vertical deformation two periods are distinguished the first one 2001 to 2003 is consistent with anticipated motions associated with the main geological and tectonic features of the island the second one 2003 to 2006 has been tentatively attributed to dilatancy in which relatively small uplift 20 40 mm occurred along the southern and southeastern parts of the island while larger magnitudes 50 mm happened at the western part paliki peninsula these large magnitudes of uplift over an extended area 50 km in conjunction with an accelerated benioff strain determined from the analysis of the seismicity in the broader region are consistent with dilatancy this effect commenced some time after 2003 and is probably centered in the area between zakynthos and cephallonia if this interpretation is correct it may foreshadow the occurrence of a very strong earthquake s sometime during 2007 to 2008 in the above designated region

late glacial holocene climate variability at the south eastern margin of the aegean sea abstract new micropaleontological palynological and geochemical results from a relatively shallow 500 m sediment core ns 14 in the south eastern aegean sea provide a detailed picture of the regional expression of sapropel s1 formation in this sub basin of the eastern mediterranean sea specifically freshwater input during 10 6 10 0 ka bp has preceded the deposition of s1 further decrease in surface water salinity is evidenced between 10 0 and 8 5 ka bp at the lower part of s1a which in respect to s1b is featured by warmer 19 5 c and more productive surface waters associated with dysoxic bottom conditions a series of coolings detected within the s1 depositional interval may be linked to outbursts of cold northerly air masses and relevant pulses in the deep intermediate water ventilation that caused the s1 interruption between 7 9 and 7 3 ka bp and culminated during the deposition of s1b with the decline of deep chlorophyll maximum dcm at 6 5 ka bp the climate instability and the relevant absence of anoxia weakened the organic matter preservation in the shallow south eastern aegean margin during the s1 times ns 14 record provides evidence for a distinct mid holocene warm up to 25 c and wet phase associated with the deposition of the sapropel like layer smh sapropel mid holocene between 5 4 and 4 3 ka bp the smh layer could represent evidence of on going albeit weak african monsoon forcing only expressed at the south eastern edge of the aegean sea its end is associated with the 4 2 ka bp northern hemisphere mega drought event and the termination of the african humid period at 3 8 ka bp

an extension of the bus asteroid taxonomy into the near infrared the availability of asteroid spectral measurements extending to the near infrared resulting from the development of new telescopic instruments such as spex rayner 2003 provides a new basis for classifying asteroid reflectance spectra we present an asteroid taxonomy classification system based on reflectance spectrum characteristics for 371 asteroids measured over the wavelength range 0 45 to 2 45 microns this system of 24 classes is constructed using principal component analysis following most closely the visible wavelength taxonomy of bus 1999 which itself builds upon the system of tholen 1984 nearly all of the bus taxonomy classes are preserved with one new class sv defined for each class we present boundary definitions spectral descriptions and prototype examples a flow chart method is presented for classifying newly acquired data spanning this wavelength range when data are available only in the near infrared range 0 85 to 2 45 microns classification is also possible in many cases through an alternate flow chart process within our sample several classes remain relatively rare only 6 objects fall into the a class 349 dembowska and 3628 boznemcova reside as the only objects in their respective r and o classes eight q class objects are all near earth asteroids we note 1904 massevitch as an outer main belt v type while 15 other v type objects have inner main belt orbits consistent with an association with vesta

impact origin of the vesta family the compelling petrographic link consolmagno and drake 1977 gaffey 1983 between basaltic achondrite meteorites and the 530 km diameter asteroid 4 vesta has been tempered by a perceived difficulty in launching rocks from this asteroid s surface at speeds sufficient to bring them to earth wasson and wetherill 1979 without obliterating vesta s signature crust i address this impasse in response to recent imaging zellner et al 1996 dumas and hainaut 1996 of a 450 km impact basin across vesta s southern hemisphere thomas et al 1997 and model the basin forming collision using a detailed two dimensional hydrocode with brittle fracture including self gravitational compression cf asphaug and melosh 1993 a 42 km diameter asteroid striking vesta s basaltic crust atop a denser mantle and iron core at 5 4 km s launches multikilometer fragments up to 600 m s without inverting distal stratigraphy according to the code this modeling together with collisional dynamical rheological and exposure age timescales marzari et al 1996 welten et al 1996 and observations of v type asteroids binzel and xu 1993 suggests a recent 1 ga impact origin for the vesta family and a possible vesta origin for earth approaching v type asteroids cruik shank et al 1991

a preliminary global map of the vector lunar crustal magnetic field based on lunar prospector magnetometer data processing and mapping of the lunar prospector magnetometer data is supported by the nasa discovery data analysis program

age of the ponta grossa dike swarm brazil and implications to parana flood volcanism the ponta grossa dike swarm pgds occurs in a nw trending 200 km wide zone exposed just east of the parana basin in southeastern brazil the predominantly basaltic dikes intrude crystalline basement paleozoic mesozoic sediments and rarely flows of the parana etendeka flood volcanic province pep the pgds resembles the failed arm of a rift rift rift triple junction related to the separation of south america and africa detailed geochemical studies of the dikes including major minor trace element and sr nd isotopic analyses indicate that they probably represent feeders for the voluminous phase of flood volcanism represented by relatively uncontaminated predominantly high tio2 lavas of the northern pep where lava accumulations reach 1700 m thick 40ar 39ar stepwise degassing data using both laser and radiofrequency induction furnace on plagioclase separates from eighteen dikes and one sill yield seventeen plateau ages three are between 120 7 1 3 ma and 125 8 0 6 ma and fourteen are clustered between 129 2 0 4 ma and 131 4 0 5 ma isochron ages are not significantly different from the plateau ages and plateau ages are adopted in all but two cases as being the most accurate age estimates the age probability distribution for the dominant pulse 131 4 0 4 to 129 2 0 4 ma shows a pronounced peak at 130 5 ma this distribution probably reflects the magma production history in the region the new geochronologic data are consistent with conclusions based on paleomagnetic and chemical stratigraphic data that the pgds is younger than the volumetrically dominant majority of volcanism in the southern pep which occurred at 133 132 ma the younger commonly ne trending dikes may reflect the initiation of full drift which was coincident with major basin development in the adjacent continental borderland at 125 120 ma the pgds may indeed represent the failed arm of a rift rift rift triple junction but the triple junction did not coincide exactly in time or space with the site that would be inferred for plume impact

effect of volcanic dykes on coastal groundwater flow and saltwater intrusion a field scale multiphysics approach and parameter evaluation volcanic dykes are common discrete heterogeneities in aquifers however there is a lack of field examples of and methodologies for comprehensive in situ characterization of their properties with respect to groundwater flow and solute transport we have applied an integrated multi physics approach to quantify the effect of dolerite dykes on saltwater intrusion in a coastal sandstone aquifer the approach involved ground geophysical imaging passive magnetics and electrical resistivity tomography well hydraulic testing and tidal propagation analysis which provided constraints on the geometry of the dyke network the subsurface saltwater distribution and the sandstone hydrodynamic properties and connectivity a three dimensional variable density groundwater model coupled with a resistivity model was further calibrated using groundwater and geophysical observations a good agreement of model simulations with tide induced head fluctuations geophysically derived pore water salinities and measured apparent resistivities was obtained when dykes hydraulic conductivity storativity and effective porosity are respectively about three one and one orders of magnitude lower than the host aquifer the presence of the dykes results in barrier like alterations of groundwater flow and saltwater intrusion preferential flowpaths occur parallel to observed dyke orientations freshwater inflows from upland recharge areas concentrate on the land facing side of the dykes and saltwater penetration is higher on their sea facing side this has major implications for managing groundwater resources in dyke intruded aquifers including in coastal and island regions but also provides wider insights on preferential pathways of groundwater flow and transport in highly heterogeneous aquifer systems this article is protected by copyright all rights reserved

geologic mapping of vesta from 1994 hubble space telescope images we utilize the 56 images of asteroid 4 vesta obtained through four mineralogically diagnostic filters by the hubble space telescope zellneret al 1997 icarus to construct a geologic map vesta s surface is found to be geologically diverse and to be dichotomous at a hemispheric scale the eastern hemisphere longitude definition from thomaset al 1997 icarus is dominated by units interpreted to be impact excavated plutonic material composed of magnesium rich and calcium poor pyroxene the mineralogy of this region is most analogous to diogenite meteorites several eastern hemisphere units which have the deepest and broadest 1 m absorption bands may contain a substantial olivine component the locations of these units are consistent with a previous map based on rotationally resolved groundbased spectroscopy gaffey 1997 icarus the western hemisphere is dominated by units interpreted to consist of a single component of iron rich and relatively calcium rich pyroxene analogous to surface basalts such as eucrite meteorites we investigate the spectral properties of 20 representative surface regions and find a correlation between the 1 m absorption band depth and albedo the units with lower albedos have shallower band depths such a relation could arise from differences in lithologies differences in surface particle sizes or from a weathering effect which decreases albedo and band depth over time because of vesta s geologic diversity and hemispheric dichotomy it is apparent that any major impact events such as those possibly related to the formation of the vesta family binzel and xu 1993 science260 186 191 did not globally resurface the planet the spectral evidence for remnants of a basaltic crust implies that the oldest units on the surface date back to the time of their emplacement most likely 4 5 byr ago if a weathering process exists which alters the albedo then the lowest albedo units such as the feature with the proposed name olbers most likely represent remnants of vesta s ancient basaltic crust

geomorphic responses to long term land use changes in eastern macedonia greece distinct phases of stream aggradation soil erosion and landscape stability in the basin of drama eastern macedonia greece over the past 7000 years can be tied directly to long term land use changes during the middle and late holocene 1 4 m of alluvial fill accumulated in the centre of the basin and along the angithis valley low levels of alluvial aggradation were recorded during the late neolithic and the early bronze age 7400 4000 cal bp in the centre of the basin along the lower course of the river xeropotamos the rate of aggradation has doubled since the late bronze age 0 5 0 6 mm year 1 compared to the holocene as a whole 0 25 mm year 1 moderate rates of alluvial fill were experienced during the late bronze age 3600 3000 cal bp but the most significant destabilisation of the soils occurred later than in many regions of greece two historical phases of alluvial aggradation and soil erosion are identified in the antique and the early byzantine era 3rd century bc 7th century ad and more significantly in the ottoman period beginning of the 15th to the 20th century ad in the latter period the rate of accumulation was three to five times greater than in the late holocene almost three millennia intervened between the arrival of the first farmers and the onset of erosion this is mainly explained by the settlement pattern during the neolithic and the early bronze age it seems that the early farmers preferred to cultivate the more stable soils on the gentle slopes at the centre of the basin during the late bronze age the land use pattern changed the soils then under cultivation on the foothills were less stable and the steeper slopes were more susceptible to erosion this limited the potential for forest restoration after the first noticeable land clearance and probably explains the extent of alluvial aggradation since the antique era the intensity of land use has increased the two phases of accelerated alluviation in historical times are clearly linked to land use changes particularly with the upstream progression of cropping and grazing onto more sensitive lands in foothills and mountainous areas though this was also influenced by climatic fluctuations the major period of aggradation in the ottoman period is clearly associated with both climatic and anthropogenic factors it seems that the early historic deforestation and agricultural activities rendered river systems more sensitive to relatively modest changes in climate

late pleistocene and holocene sea level change in greece and south western turkey a separation of eustatic isostatic and tectonic contributions summary sea level change during late pleistocene and holocene times is a combination of eustatic isostatic and tectonic contributions in the central mediterranean sea region of greece and western turkey the isostatic components are important due to the changing gravitational potential of the earth the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans including the mediterranean changes in relative sea level due to these glacio hydro isostatic adjustments have reached amplitudes of 1 mm yr 1 during the last few thousand years a model for the isostatic contribution to sea level change including the movement of shorelines due to the combined eustatic isostatic changes is developed based on earth model and ice sheet parameters estimated from sea level observations from other areas comparisons of this model with observations of sea level change permit rates of vertical movement to be estimated for late holocene time allowance for the isostatic factors makes a significant difference to these rates the plains of argolis lakonia messinia and navarine in the southern peloponnese for example appear to be tectonically stable on time scales of a few thousand years and longer consistent with the position of the last interglacial shoreline close to the present day sea level the observations here of a rising sea level are largely the consequence of the glacio hydro isostasy and not of a long term tectonic process crete as a whole is subject to tectonic uplift but at variable rates and forms part of an arcuate zone of uplift extending from rhodes and karpathos in the east to kithera in the west at rates that locally exceed 4 mm yr 1 the southern shore of the gulf of corinthos is also subject to uplift at rates approaching 1 5 mm yr 1 these isostatically corrected estimates for the past few thousand years are in agreement with longer term estimates based on the position of the last interglacial shoreline only on the perachora peninsula do the tectonic rates over these two time intervals appear to be in disagreement with the late holocene rates being much higher than the long term rates

comprehensive approaches to 3d inversion of magnetic data affected by remanent magnetization three dimensional 3d inversion of magnetic data to recover a distribution of magnetic susceptibility has been successfullyusedformineralexplorationduringthelastdecade however the unknown direction of magnetization has limited the use of this technique when significant remanence is present we have developed a comprehensive methodology for solving this problem by examining two classes of approaches and have formulated a suite of methods of practical utility the first class focuses on estimating total magnetization direction and then incorporating the resultant direction into an inversion algorithm that assumes a known direction thesecondclassfocusesondirectinversionoftheamplitude of the magnetic anomaly vector amplitude data depend weaklyuponmagnetizationdirectionandareamenabletodirect inversion for the magnitude of magnetization vector in 3d subsurface two sets of high resolution aeromagnetic dataacquiredfordiamondexplorationinthecanadianarctic areusedtoillustratethemethods usefulness

was the piraeus peninsula greece a rocky island detection of pre holocene rocky relief with borehole data and resistivity tomography analysis according to historical documents piraeus was a rocky island consisting of the steep hill of munichia known as modern day kastella it was connected to the mainland by a low lying stretch of land halipedon that would flood with sea water most of the year and was used as a salt field whenever it dried up apart from being an area of archaeological interest the extended area of halipedon is densely populated thus being of geotechnical interest and is currently being investigated through borehole and geophysical data analysis 52 boreholes were lithologically geomorphologically analyzed and results from 11 resistivity tomography profiles were considered lithostratigraphy of the borehole data was classified into three lithostratigraphic units cultural deposits pleistocene holocene deposits pre holocene bedrock marls of piraeus the deeper unit shows a big depression in the southeastern part of the survey area and a circular sinking channel in its north part these depressions were probably covered by the sea at a time when the southern part of the piraeus peninsula was an island this is confirmed by stratigraphical and geophysical investigation in the area where resistivity tomography profiles could be performed the big southeastern depression is covered by the river sediments implying a high sedimentation rate

vesta s uv lightcurve hemispheric variation in brightness and spectral reversal abstract spectra of asteroid 4 vesta obtained in october 1990 with the international ultraviolet explorer are reanalyzed and reinterpreted a large portion of the eastern hemisphere based on the prime meridian definition of thomas et al 1997a is darker at uv wavelengths than much of the western hemisphere the uv lightcurve is in contrast with the visible lightcurve which shows that the eastern hemisphere is brighter than the western these iue spectra of vesta thus may be evidence for the spectral reversal first seen on the moon by apollo 17 where the visibly brighter lunar highlands are darker than the maria at far uv wavelengths this effect was linked to space weathering when it was noted wagner et al 1987 that the spectral reversal appears in the laboratory spectra of lunar soils but not powdered lunar rocks we investigate vesta s uv lightcurve and spectral reversal and its possible connection with space weathering the addition to grain coatings of small amounts of submicroscopic iron smfe through vapor deposition causes drastic spectral changes at uv visible wavelengths hapke 2001 while the longer wavelength spectrum remains largely unaffected other laboratory results e g hiroi and pieters 1998 indicate that the uv visible wavelength range is affected by simulated weathering processes in a manner similar to what is seen on vesta it is likely that vesta has experienced relatively minor amounts of space weathering as indicated by the spectral reversal along with the subtle visible near infrared weathering effects e g binzel et al 1997

compositional variations in the vestan rheasilvia basin abstract we present and describe the maps of spectral parameters such as pyroxene band centers and depths reflectance at 1 4 m and 2 8 m band depth in the rheasilvia quadrangle we found a broad anti correlation between pyroxene band centers and depths while the reflectance is not correlated with the pyroxene spectral parameters in addition we found that the rheasilvia quadrangle is free of oh absorption signatures we also derived lithological maps with improvements in the spatial resolution with respect to previous lithological maps of the same region we confirm that the central mound is dominated by eucritic howarditic pyroxene while diogenitic lithology has been found mainly in a region delineated by tarpeia severina and mariamne craters we found small scale variations in the composition of pyroxene these variations identify lithological units that extend for tens of km although small units of less than 1 km have also been found we consider this fact as an indication of a high level of compositional heterogeneity within the vestan crust

the socio environmental history of the peloponnese during the holocene towards an integrated understanding of the past published archaeological palaeoenvironmental and palaeoclimatic data from the peloponnese in greece are compiled discussed and evaluated in order to analyse the interactions between humans and the environment over the last 9000 years our study indicates that the number of human settlements found scattered over the peninsula have quadrupled from the prehistoric to historical periods and that this evolution occurred over periods of climate change and seismo tectonic activity we show that societal development occurs both during periods of harsh as well as favourable climatic conditions at some times some settlements develop while others decline well known climate events such as the 4 2 ka and 3 2 ka events are recognizable in some of the palaeoclimatic records and a regional decline in the number and sizes of settlements occurs roughly at the same time but their precise chronological fit with the archaeological record remains uncertain local socio political processes were probably always the key drivers behind the diverse strategies that human societies took in times of changing climate the study thus reveals considerable chronological parallels between societal development and palaeoenvironmental records but also demonstrates the ambiguities in these correspondences and in doing so highlights some of the challenges that will face future interdisciplinary projects we suggest that there can be no general association made between societal expansion phases and periods of advantageous climate we also propose that the relevance of climatic and environmental regionality as well as any potential impacts of seismo tectonics on societal development need to be part of the interpretative frameworks

chemotaxonomy in some mediterranean plants and implications for fossil biomarker records the increasing utilization of n alkanes as plant derived paleo environmental proxies calls for improved chemotaxonomic control of the modern flora in order to calibrate fossil sediment records to m

fugitives from the vesta family abstract spectroscopic observations of asteroid 4 vesta and numerous members of the vesta family located in the inner asteroid belt have determined that these objects have reflectance properties of basaltic material a plausible hypothesis is that the surface of vesta was punctured by large impacts in the past which dispersed fragments of its basaltic crust into space and produced one of the most prominent asteroid families ever created in the belt until recently vesta was the only known object in the asteroid belt which underwent differentiation and survived to the present epoch since 2000 many new small basaltic asteroids have been discovered in the inner and outer parts of the asteroid belt possibly representing fragments from distinct differentiated bodies these discoveries may help us to better understand the number and nature of objects in the inner solar system that underwent geological differentiation to investigate these issues we performed extensive numerical simulations whose aim was to reproduce as precisely as possible the dynamical evolution of vesta s ejected fragments over timescales comparable to the family s age specifically we numerically integrated the orbital evolution of 6600 test bodies with orbits that started within the vesta family and dynamically evolved over 2 gy our model included gravitational perturbation of all planets except mercury and the yarkovsky effect the results show that a relatively large fraction of the original vesta family members may have evolved out of the family borders defined by clustering algorithms and are now dispersed over the inner asteroid belt we compared the orbital distribution of our model fragments with the orbital locations of known basaltic asteroids in various parts of the inner main belt to find that i most basaltic asteroids with semimajor axis a 2 3 au located outside the vesta family s borders in the inner main belt including 809 lundia and 956 elisa are most likely fugitives from the vesta family that have evolved to their current orbits via various identified dynamical pathways our results also suggest that the vesta family is at least 1 gy old ii interestingly orbits of many basaltic asteroids with 2 3 a 2 5 au like those of 4796 lewis and 5379 abehiroshi are displaced from the vesta family to low inclinations and are not obtained in our simulations with sufficient efficiency we propose that i these small basaltic asteroids may be fragments of differentiated bodies other than 4 vesta or ii they were liberated from the vesta s surface before or during the late heavy bombardment epoch 3 8 gy ago and their orbital inclinations separated from that of vesta when secular resonances swept through the region

synergy of tectonic geomorphology applied geophysics and remote sensing techniques reveals new data for active extensional tectonism in nw peloponnese greece abstract in tectonically active areas such as in the northwest peloponnese of western greece geomorphic processes are strongly influenced by active faulting in many cases such faults cannot be easily identified in this paper we apply multidisciplinary analysis morphotectonic indices neotectonic mapping geophysical surveys and remote sensing techniques to map the recently recognized east west trending pineios river normal fault zone with a high degree of accuracy and to better understand its contribution to the evolution of the ancient region of elis during holocene time fault activity seems to be related to frequent changes in river flow patterns and to displacements of the nearby shoreline we argue that fault activity is the main reason for migration of pineios river mouth as documented for several time periods during historical time quantitative constraints on deformation caused by the faulting were applied through the application of the morphotectonic indices proposed in this paper including drainage network asymmetry and sinuosity and mountain front sinuosity all of which indicate that this is a highly active structure slip rates calculated to be as high as 0 48 mm yr for the last 209 ka based on previously published dating were verified by applied geophysical methods the fault surface discontinuity was identified at depth using vertical electrical resistivity measurements and depositional layers of different resistivity were found to be clearly offset displacement increases toward the west reaching an observed maximum of 110 m the most spectacular landform alteration due to surface deformation is the north south migration of the river estuary into completely different open sea areas during the late quaternary mainly during the holocene the sediment transport path has been altered several times due to these changes in river geometry with and the most recent seeming to have occurred almost 2000 years ago the river estuary migrated to its contemporary position along the southern coast settled on the hanging wall inducing retrograding of the northern coast and settled on the foot wall with rates reaching the order of 0 52 m yr as concluded from historical and recently acquired remote sensing data

the ad 365 crete earthquake and possible seismic clustering during the fourth to sixth centuries ad in the eastern mediterranean a review of historical and archaeological data abstract historical and archaeological data are used to test geological claims that in the fourth to sixth centuries ad the eastern mediterranean experienced an unusual clustering of destructive earthquakes the early byzantine tectonic paroxsym a review of historical accounts of a notable earthquake at this time that of 21 july ad 365 indicates that this event destroyed nearly all the towns in crete and was followed by a tsunami which devastated the nile delta the ad 365 event was also probably responsible for reported or observed destruction in ancient towns of west cyprus and libya this earthquake is most likely to be identified with a hellenic arc subduction zone event of great m 8 magnitude as testified by up to 9 m of uplift in western crete dated by previous geological studies to around this time historical and archaeological data also support the hypothesis that the fourth to sixth centuries ad was a period of abnormally high seismicity in the eastern mediterranean the high seismicity rates of this period may reflect a reactivation of all plate boundaries in the region dead sea transform east anatolian fault north anatolian fault hellenic arc cyprus arc fault

the history of holocene soil erosion in the phlious basin ne peloponnese greece based on optical dating anthropogenic induced soil erosion has occurred in the mediterranean during historic and pre historic times but precise timeframes for periods of past soil erosion are largely missing due to the lack of datable material and suitable dating methods in this study optical dating of colluvial sediments from the phlious basin ne peloponnese greece was applied the results show that soil erosion derived colluvium formed under a mediterranean type climate can be successfully dated by optical stimulated luminescence osl and a high resolution chronology of holocene soil erosion could be established colluvial formation occurred in the early holocene but increased distinctly in the seventh millennium parallel with the onset of the neolithic the start of farming activities other periods of strong colluviation are the middle and late bronze age second millennium the roman period first century to sixth century and the period since the sixteenth century rates of reduced colluviation occurred during