rate of outward growth of the mediterranean ridge accretionary complex abstract the position as a function time of the deformation front on the southwest flank of the mediterranean ridge accretionary complex is constrained as follows 1 a the deformation front is now active 2 b the site of core ban84 05gc was still near the abyssal plain when displaced shallow water benthic foraminifera of inferred african provenance were redeposited within an upper pliocene age unit 3 c the site of core ban84 05gc on the outer flank of the mediterranean ridge was already within the topographically rugged accretionary complex when a pliocene debris flow was emplaced 4 d dsdp site 125 had already been uplifted into a topographically elevated position when lower pliocene pelagic ooze was deposited 5 e a gypsum bearing breccia in dsdp site 125 requires that the site was either on the abyssal plain or within the tectonically active outer perimeter of the accretionary complex during the messinian salinity crisis 6 f dsdp site 377 had already been uplifted into a topographically elevated position when middle miocene age pelagic marl was deposited 7 g dsdp site 377 was still on or near the abyssal plain when early to lower middle miocene age smectite bearing turbidites of inferred african provenance were deposited and 8 h the mediterranean ridge began to grow by offscraping against a backstop formed by the alpine nappes of the hellenic arc at the time that subduction began 33 ma together these constraints define a range of potential growth curves for the mediterranean ridge with a rate of outward growth of approximately 0 5 to 2 cm yr this growth rate is faster than that inferred for most other modern accretionary prisms both as an absolute value and as a fraction of the subduction velocity an unusually thick incoming section and or an unusually weak evaporitic decollement may contribute to the rapid growth rate the inferred age of accretion does not increase linearly with distance from the deformation front rather there is an apparent acceleration of the rate of outward growth through time this observation may reflect a true acceleration of growth rate in response to the onset of back arc extension in the overriding plate aegean sea and or in response to the development of a weak basal decollement following the introduction of halite into the incoming stratigraphic section alternatively the non linearity of the age vs distance curve may indicate that shortening of the offscraped sediments continues across the breadth of the mediterranean ridge rather than being confined to the outer flank

global positioning system measurements of present day crustal movements in the arabia africa eurasia plate collision zone we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1994 at 54 sites extending east west from the caucasus mountains of southern russia georgia and armenia to the aegean coast of turkey and north south from the southern edge of the eurasian plate pontus block to the northern edge of the arabian platform viewed from a eurasia fixed reference frame sites on the northern arabian platform move n38 13 w at 20 3 mm yr roughly consistent with the velocity implied by nuvel 1a circuit closure n23 7 w at 24 2 mm yr the motion of arabia appears to be transferred directly to the region of turkey north of the suture however eastern turkey is characterized by distributed deformation while central western turkey is characterized by coherent plate motion involving westward displacement and counterclockwise rotation of the anatolian plate internal deformation within the central part of the anatolian plate is less than 2 mm yr the anatolian plate is decoupled from eurasia along the right lateral strike slip north anatolian fault naf this different response in eastern and western turkey to the collision of arabia may result from the different boundary conditions the hellenic arc forming a free boundary to the west and the asian continent and oceanic lithosphere of the black and caspian seas forming a resistant boundary to the north and east we derive a best fitting euler vector for anatolia eurasia motion of 29 2 0 8 n 32 9 0 4 1 3 0 1 m y the mapped surface trace of the naf corresponds well to a small circle about this pole the new euler vector implies an upper bound for naf slip rate of 30 2 mm yr i e assuming all relative motion is accommodated along the naf using the nuvel 1a euler vector for arabia eurasia and the gps euler vector for anatolia eurasia we determine an arabia anatolia euler vector of 31 2 n 45 2 e 0 9 0 1 m y and an upper bound on the east anatolian fault slip rate of 15 3 mm yr the aegean trough region of western turkey deviates significantly from coherent plate rotation in addition to rotating with anatolia this region shows roughly n s extension at a rate of 14 5 mm yr taken together with satellite laser ranging results along the hellenic arc the contemporary pattern of deformation indicates increasing motions toward the arc suggesting that the westward displacement and counterclockwise rotation of anatolia is driven both by pushing from the arabian plate and by pulling or basal drag associated with the foundering african plate along the hellenic subduction zone

deformational styles of the eastern mediterranean ridge and surroundings from combined swath mapping and seismic reflection profiling abstract recent swath mapping and seismic reflection profiling across the eastern levantine branch of the mediterranean ridge mr in the eastern mediterranean sea illustrate a strong variability of the deformational styles that characterize this precollisional accretionary prism along a north south cross section of the mr a structural analysis based on surface mapping combined with vertical seismic reflection data reveals two main structural domains a southern outer domain consists of a series of three disconnected distinct fold belts folding affects a sedimentary cover which includes an approximately 2 km thick pliocene and quaternary wedge in this domain resting on fairly thick messinian evaporitic sequences that act as probable decollement layers the mr inner domain includes three regions showing evidences of strong internal deformations and of numerous probable mud cones and mud flows but no seismic evidence of significant underlying messinian evaporites can be detected the inner sub regions are thrusting northwards over an area made of faulted and locally uplifted acoustic basement blocks that constitute the southernmost extension of the crete continental margin acting as a continental buttress for the mr this innermost domain is itself structurally disconnected from the crete continental margin by the en echelon pliny troughs system that shows evidence of left lateral displacement altogether the different structural and sedimentary cover patterns reveal a strong contrast between both mr inner and outer domains and important lateral variations within the inner mr itself strike slip faulting seams to characterizes both areas and large scale mud accumulations potentially exist in the northern one our results support a model of imbricated accretionary prisms including at least two stages 1 a pre messinian stage during which the inner mr probably developed in response to northward subduction of the african lithosphere beneath southern europe and 2 a messinian to post messinian period during which the kinematics of the aegean anatolian microplates and the presence of thick messinian deposits became prevalent and which led to the creation of the outer mr folded wedge piling against the previous one in our interpretation the occurrence of thick messinian evaporites in this area induces important local and regional modifications of the structural pattern strike slip activities reflect partitioning related to oblique subduction and likely lateral escape of the sedimentary cover in the whole studied area

from foreland to forearc domains new multichannel seismic reflection survey of the mediterranean ridge accretionary complex eastern mediterranean abstract the mediterranean ridge of the eastern mediterranean sea is a huge accretionary wedge emplaced as a consequence of the africa aegean plate convergence that has a rate estimated at 40 mm yr processing of recent multichannel seismic data and integration with previous results seismic profiling swath bathymetry sonar have facilitated the study of the overall deformation pattern of the area which includes three distinct major structural domains facing various forelands 1 1 the outer domain is bounded southward by the present day wedge toe and towards the north by topographic slope breaks and clear changes in deformational style beneath the ionian and levantine mediterranean ridge branches the base of messinian evaporites seems to act as a major decollement level 2 2 the central or crestal domain the shallowest one shows evidence of mud diapiric and mud volcano activity and is overthrusting northward over the inner domain facing the libyan margin this area which displays spectacular mud volcano fields appears much wider and shallower 3 3 the less deformed inner domain is bounded northward by the hellenic trench system beneath its ionian inner area seismic velocities characteristic of continental crust have been recorded while within its levantine region it is made of a series of disconnected and uplifted basement blocks strabo seamounts along the matapan and pliny trenches structures which could be caused by transpressive deformation are locally observed we believe that both the north south structural arrangement and the clear west east lateral variations of the mediterranean ridge relate to its progressive collision against the libyan margin promontory this event which may have initiated 5 6 myr ago may have induced a a differentiated paleogeography of messinian evaporites later available for tectonic accretion leading to the further lateral structural variations of the outer domain and b strain partitioning between the central mediterranean ridge and the hellenic trench system

annual rainfall and nitrogen isotope correlation in macropod collagen application as a palaeoprecipitation indicator abstract collagen has been extracted and analysed for 15 n from modern kangaroos macropods macropus eugenii m antilopinus m fuliginosus m rufus m robustus in western australia and south australia comparison of nitrogen isotope ratios with annual rainfall for the respective areas produced a good negative correlation for macropods but not for other marsupials this may be related to metabolic adaptations in macropods to compete against water loss hence the correlation between 15 n and annual rainfall may be species specific nitrogen isotope analyses on collagenic material extracted from fossil macropods macropus spp have been determined from two late pleistocene deposits in south australia corroboration with spore pollen and sedimentological data confirm that 15 n of collagenic material can be used as a proxy for palaeoprecipitation levels in australia this has great potential for understanding palaeoclimatic changes especially drought periods in australia during the pleistocene

european mediterranean regional centroid moment tensors 1997 2000 the mediterranean region is seismically very active and undergoing rapid deformation earthquakes as strong as m 6 are present but relatively rare on the other hand moderate magnitude seismicity 4 5 m 5 5 is widespread and often damaging an improved knowedge of moderate magnitude earthquakes can contribute significantly to a better understanding of active tectonics in the region harvard centroid moment tensors cmt today represent the most widely used reference for reliable source mechanisms but modelling seismic sources with the cmt technique for earthquakes with magnitude less than m 5 5 5 is quite difficult since 1997 we are using an extension of the standard cmt algorithm to compute regional centroid moment tensors rcmt for moderate magnitude earthquakes mw as low as 4 0 analyzing intermediate period surface waves from regional and teleseismic seismograms we routinely apply the algorithm to european mediterranean seismicity to produce a catalog of seismic moment tensors for events with magnitude between 4 5 and 5 5 which generally are not included in the harvard cmt catalog in this paper we show the results for earthquakes that occurred between 1997 and 2000 consisting of 252 solutions and we discuss the characteristics of the catalog and the areas where these new data are most relevant

wide angle images of the mediterranean ridge backstop structure the mediterranean ridge is an accretionary wedge consisting of a large pile of tectonically deformed sediments in the past the mediterranean ridge has been interpreted as a prism related to hellenic subduction however geophysical evidence pasiphae cruise 1988 has indicated the presence of a high velocity body southward of the hellenic trench which was subsequently interpreted as an extended continental backstop during the recent imerse project coincident wide angle and normal incidence seismic data were collected over the ridge along the ne sw medriff corridor explora cruise 1994 the objectives of the imerse project were to acquire the seismic observations necessary for a high resolution structural model of the western mediterranean ridge including the structure of the newly interpreted continental backstop here we present the results of recent re modelling of two ship expanding spread seismic refraction data esp 8 and 9 recorded during the pasiphae cruise the modelling of these data has allowed an approximate constraint on the position of the juncture between the mediterranean accretionary complex and its buttress also presented are processing and modelling results of the recently acquired imerse wide angle data travel time modelling of these data has allowed the construction of six multi azimuth velocity depth models these models show the existence of high velocity material at depth p wave velocity 5 km s inferred to be extended backstop and constrain its southward extent all models show the presence of a messinian evaporite layer near the surface the evaporite layer is observed to vary in thickness from 0 to 2 0 km with the existence of local thickening and thinning due to depositional factors tectonism and salt dissolution in addition combined analysis of the wide angle velocity models with coincident seismic reflection and swath bathymetry data indicates that the geometry of the continental backstop varies laterally as a consequence of transform faulting possibly related to the southward rotation of the peloponnesus thrust sheet and backstop emplacement

investigation of palaeodiet in the north caucasus south russia bronze age using stable isotope analysis and ams dating of human and animal bones abstract this paper addresses the question of human palaeodietary adaptation in the eneolithic and early bronze age periods of the north caucasus south russia using stable isotope analysis one of the key questions is the presence of fish in the diet ams radiocarbon dating of archaeological bone collagen has also been carried out to investigate potential radiocarbon reservoir effects in human skeletal material as a result of an aquatic diet a fish component has previously been suggested in the diet of iron age and bronze age humans across eurasia by isotopic research and radiocarbon dating of contemporaneous human and animal bones in the north caucasus however isotopic data is scant this study presents a new set of stable isotopic data from several early bronze age sites mainly belonging to the maikop culture of the north caucasus the results show that the diversity in climate and environment across the northern caucasus may be a causal factor for the patterns observed in the stable isotope values of terrestrial herbivores this affects the isotopic values of the humans consuming them the differences in 15 n and 13 c ranges of both humans and fauna were found to correlate strongly with geography and climate the most enriched isotopic values are found in the dry steppe areas to the north overall a relatively high enrichment in 15 n values of humans compared to local terrestrial herbivores and carnivores was observed this indicates that aquatic resources were probably part of the bronze age diet in the region although the extent of this needs further investigation the dramatic effect of environmental factors on isotopic values in the early bronze age of the north caucasus illustrates how confident conclusions cannot be drawn on the basis of a small number of samples from widely differing regions and time periods radiocarbon dating can provide a useful tool for identifying dietary derived reservoir ages in humans potentially caused by a fish diet with two possible exceptions the nine human animal bone pair dated as part of this study showed no consistent indication for a consistent reservoir effect

deformation of the western mediterranean ridge importance of messinian evaporitic formations abstract multichannel seismic data were acquired across several areas of the mediterranean ridge m r in the eastern mediterranean sea during the mcs prismed survey march 1993 the m r is a wide high standing and elongated swell emplaced between the southern aegean and africa as a consequence of the long term convergence and the ongoing collision between europe and africa sedimentary piling and associated deformation have built a thick deformed sediment wedge the internal geological structures of which remain poorly understood processing of two mcs lines pm 02 and pm 03 across the western branch of the mediterranean ridge reveals that messinian evaporite bearing formations which were deposited within the deep ionian oceanic basin 5 my ago play an important part in the present structural deformation of the m r accretionary wedge within the outer m r the messinian lower evaporites are believed to act as one of the main decollement levels while the top of these formations may operate as a disharmonic layer below thin plio quaternary sediments the present day m r toe appears to be affected by ductile flow deformation however most of the accreted outer wedge is believed to have resulted from the progressive piling up and associated thrusting of messinian and overlying plio quaternary sediments toward the northeast i e toward the central m r domain a major backthrust zone indicates a structural boundary between the outer wide and convex m r and its inner rather flat domain which is inferred to act as a backstop

structure of the mediterranean ridge accretionary complex from seismic velocity information seismic velocities obtained from ocean bottom hydrophone expanding spread profile and multi channel seismic data were used to compile a velocity model for the mediterranean ridge along a 220 km long transect extending from the sirte abyssal plain to the cleft region near the hellenic trough a 200 300 m thin layer of plio quaternary sediments with velocities of 1800 2200 m s 1 covers the whole ridge the messinian evaporites 4000 4500 m s 1 occur in the southwest as a tectonically thickened layer and in a basin just northeast of the crest of the ridge in the intervening region however the evaporites appear absent and the seismic velocities are generally lower arched reflectors imaged in the depth migrated section suggest that the sediments beneath the ridge crest belong to a pre messinian accretionary wedge beneath the messinian evaporites a northeastward thinning layer of probable tertiary sediments shows laterally increasing velocities from 3300 m s 1 to 4600 m s 1 assuming that the layer thinning is caused by compaction due to increased overburden alone we have calculated a porosity reduction from 15 to 4 and an associated fluid expulsion of 10 km3 km 1 along the trench axis this corresponds to c 60 of the initial fluid volume of an undeformed sediment column from the abyssal plain the almost impermeable evaporitic cap over these sediments leads to high fluid pressures at the base of the evaporites likely to make this horizon the basal decollement of the modern accretionary system a 2 5 km thick unit of probable mesozoic carbonates with velocities of 4500 4600 m s 1 is inferred at c 8 km depth the top of the oceanic crust occurs at a depth of about 10 km the results from this study have widespread implications for the understanding of the regional geological history

crustal investigation of the hellenic subduction zone using wide aperture seismic data abstract we present the results of a wide aperture seismic onshore offshore study crete seismic experiment in the cretan region as part of the hellenic arc compressional system three seismic lines were carried out on and around the island of crete in order to investigate the crustal structure of the region up to 119 three component recording stations were deployed on each profile that observed seismic energy generated by a 48 l airgun array and eight 20 kg landshots a total of 6208 shots were fired upon completing the fieldwork the vertical components of all stations were evaluated 300 common receiver gather crg sections of the ocean bottom seismographs obs and land stations as well as 100 common source gather csg sections of the land shots and selected airgun shots were compiled and modeled in order to generate a 2d p wave velocity depth model for each profile the accuracy of the model depends on the depth and position along the profiles and does not exceed 5 for both depth and p wave velocity we identified strong lateral variations in crustal and sedimentary thickness mainly in a north south direction but also along strike east west the crust is continental and has a maximum thickness of 32 5 km below northern central crete its subdivision in an upper v p 5 8 6 3 km s locally up to 6 5 km s and a lower v p 6 4 6 9 km s part is justified by a first order discontinuity with v p velocity a contrast of up to 0 6 km s the eastern part of crete shows a significantly thinner crust of 24 to 26 km to the north the crustal thickness decreases to 15 km below the central cretan sea the prominent decrease of the moho depth north of central crete is interpreted to represent the northern end of a microcontinent that was subducted in oligocene times and later surfaced by buoyant escape stockhert et al 1999 thomson et al 1999 the p t t d history of the high pressure rocks of crete greece denudation by buoyant escape in exhumation processes normal faulting ductile flow and erosion ring u lister g willet s brandon m eds spec publ of the geol soc of london p 154 to the south and southwest of the island the continental crust gradually thins to a minimum of 17 km and at approximately 100 km off the southern coast of crete it is in contact with oceanic crust below the mediterranean ridge upper mantle velocities were determined to be 7 7 km s below the cretan sea and 8 0 km s south of crete below the continental cretan crust a 6 to 7 km thick layer with v p velocities between 6 6 and 7 1 km s was identified on each line and could be followed by reflections to a depth of 42 km it is decoupled from the overlying continental crust at central crete and is interpreted as oceanic crust presently under subduction towards the nne below the aegean sea

physical properties and state of the crust and upper mantle of the eastern mediterranean sea deduced from geophysical data abstract by evaluating the geophysical information available for the eastern mediterranean sea ems a crustal thickness map and some conclusions as to the nature of the crustal type were drawn it was found that the ionian abyssal plain is floored by an oceanic type of crust which is 14 km thick and covered by sediments of the order of 8 km thick the herodotus abyssal plain in the levantine sea is floored by a crust 22 km thick and covered by sediments ranging between 10 and 15 km thick the eastern mediterranean rise extending more or less continuously from the apulian plateau to rhodes and the south of the antalya basin is of a thickness ranging between 28 and 34 km the thickness of its sedimentary cover is of the order of 10 km the borders of the eastern mediterranean sea are built up of thick continental crust for example the hellenides of western greece range between 40 and 44 km thick and western turkey has a similar crustal thickness the crust of sicily also exceeds 40 km whereas the southern and eastern borders of the ems are approximately 30 32 km thick tectonically the northern border of the ems is built up of active continental margins defined by the calabrian hellenic and cyprus antalya arcs whereas the southern border represents a passive continental margin controlled mainly by subsidence and stretching to the east the dead sea megashear limits the area the deep basins of the eastern mediterranean sea are tectonically controlled by subsidence and partial stretching the mediterranean ridge or rise is still an area of dispute regarded by some authors as a subsiding continental fragment and separated from the hellenic arc by the hellenic trench whereas others consider it to be a zone of crustal shortening thickened mainly by thrusting both the western and southwestern borders of the mediterranean rise and the hellenides are controlled by compressional processes similar to those deforming the calabrian arc the stravo and pliny trenches to the east southeast border of the hellenic arc are partly affected by strike slip movements various plate tectonic models of the area have been proposed by several authors though the complexity of the deformation hardly permits reliable reconstructions the lack of reliable paleomagnetic information and the absence of linear magnetic anomalies do not favour the application of plate tectonic concepts vertical processes due to the uprising of lithothermal systems below the hellenic and calabrian arcs may also be regarded as the driving force controlling the present day deformation

p and s deep velocity structure of the hellenic area obtained by robust nonlinear inversion of travel times we derived a new model for the p and s velocity structure of the lithosphere in the subduction area of the hellenic arc and the aegean sea from the inversion of travel times of local events the inversion technique applied is nonlinear since three dimensional ray tracing is incorporated at the same time an appropriate preconditioning of the final linearized system is used in order to reduce ray density effects on the results the p s coherency is controlled by an additional damping of the vp vs ratio the study focuses mainly on the structure of the hellenic subduction in the southern aegean region interesting features and details of the subducted slab can be recognized in the final tomographic images on the western part the shallower section of the slab is dipping at a very small angle 10 this changes to approximately 25 for the deeper part of the subduction resulting in a prominent kink at a depth of about 70 km which is in accordance with the general characteristics of the associated benioff zone the smaller eastern part of the slab is not resolved with the same detail but a clearly steeper subduction zone can be recognized moreover detailed information about the crustal thickness variations are inferred from the velocity structure and correlate very well with the existing results from refraction experiments finally the results confirm the recent suggestion concerning the existence of a low velocity crustal layer at shallow depths 10 15 km in the accretionary prism of the alpine belt

vegetation phytomass and carbon storage in northern eurasia during the last glacial interglacial cycle and the holocene abstract the phytomass the biomass of terrestrial vegetation is one of the main reservoirs of carbon as carbon makes up approximately 0 45 of the phytomass by weight ajtay g l ketner p duvigneaud p 1979 terrestrial primary production and phytomass in bolin b degens e t kempe s ketner p eds the global carbon cycle scope 13 wiley chichester pp 123 181 during the glacial interglacial climatic rhythm both composition and geographical distribution of vegetation over northern eurasia have been repeatedly subjected to major changes accompanied by corresponding changes of phytomass and carbon storage of special interest are three key intervals within the last 125 000 years the mikulino eem interglacial optimum about 125 ka bp the last glacial maximum 18 20 ka bp and the holocene optimum 5 5 6 ka bp these intervals correspond to the extreme states of the environment vegetation which existed in northern eurasia 125 18 20 and 5 5 6 ka bp accumulated 377 1 gt 66 1 gt and 292 1 gt of phytomass which corresponds to 169 7 gt 29 9 gt and 131 4 gt of carbon respectively compared to present day carbon storage in the phytomass of potential vegetation taken as 100 these values are 155 27 and 120 respectively

the hellenic subduction zone a tomographic image and its geodynamic implications new tomographic images of the hellenic subduction zone demonstrate slab penetration in the aegean upper mantle to depths of at least 600 km beneath greece the lower part of the slab appears to be detached at a depth of about 200 km whereas it still seems to be unruptured beneath the southern aegean schematically we derive minimum time estimates for the duration of the hellenic subduction zone that range from 26 to 40 ma this is considerably longer than earlier estimates which vary between 5 and about 13 ma

crustal thickness beneath libya and the origin of partial melt beneath as sawda volcanic province from receiver function constraints this study investigates crustal thickness and properties within the libyan region results obtained from 15 seismic stations belonging to the libyan center for remote sensing and space science are reported in addition to 3 seismic stations publically available using receiver functions the results show crustal thicknesses ranging from 24 km to 36 km with uncertainties ranging between 0 10 km to 0 90 km more specifically crustal thickness ranges from 32 km to 36 km in the southern portion of the libyan territory then becomes thinner between 24 km and 30 km in the coastal areas of libya and thinnest between 24 km and 28 km in the sirt basin the observed high vp vs value of 1 91 at one station located at the as sawda volcanic province in central libya indicates the presence of either partial melt or an abnormally warm area this finding suggests that magma reservoirs beneath the libyan territory may still be partially molten and active thereby posing significant earthquake and volcanic risks the hypothesis of an active magma source is further demonstrated though the presence of asthenospheric upwelling and extension of the sirt basin this study provides a new calculation of unconsolidated sediment layers by using the arrival time of the p to s converted phases the results show sediments thicknesses of 0 4 km to 3 7 km with the vp vs values ranging from 2 2 to 4 8 the variations in crustal thickness throughout the region are correlated with surface elevation and bouguer gravity anomalies which suggest that they are isostatically compensated

fish tanks of eastern crete greece as indicators of the roman sea level abstract the ancient fish tanks and fish traps of crete are relics of the roman domination of the island they were usually constructed near the major urban centers of that period the direct relationship of their various functional characteristics with past sea levels and the relatively accurate determination of their construction dates establish them as sensitive indicators of sea level change through space and time the fish tanks presented in detail in this study namely those of matala chersonissos mochlos and sitia and the fish trap in the gulf of zakros have all been reported recorded and or interpreted in regard to their operation by previous researchers in the absence of a comprehensive interdisciplinary approach to the issue uneven methodologies inaccurate data and wrong measurements have led to erroneous conclusions about sea level during their operation and about the size and direction of vertical tectonic movements in eastern crete during the upper holocene the present study is based on a new underwater survey in the course of which the architectural and functional features of the ancient constructions were reexamined precisely their depth from modern sea level was measured and their relationship with coastal landforms indicative of a past sea levels was investigated a review of their manner of operation and their modern submerged position allowed the definition of a roman mean sea level 1 24 m 0 09 m below the present one the submersion of the central and eastern parts of crete included in the same tectonic block with a total length of at least 150 km at an average tectonic rate of 0 65 mm year during the last 1900 100 years occurred as is shown by historical evidence during a paroxysmal tectonic event probably related to the strong earthquake of 1604

records of climatic changes in the carbonate profiles of russian chernozems abstract the carbonate profiles of chernozems bear important information on soil processes and can be successfully used for paleoenvironmental reconstruction in the northern caucasus region russia carbonate profiles of chernozems were compared under anthropogenic irrigation and natural changes of moisture regime the results for irrigation served as the basis for understanding the response to natural climatic changes a soil chronosequence consisting of soils buried under archaeological mounds dated to 5000 3800 4000 and 1600 1700 bp and modern surface soils was studied in a similar way the soils buried 5000 and 3800 4000 bp had distinctive migrational and segregational carbonate accumulations cas the migrational forms occurred in the surface horizons and contained 89 92 calcite with the highest dissociation temperatures in the soils buried 1600 1700 bp the carbonate profile was clearly defined in terms of migrational cas they occurred only in the deeper horizons had no clear boundaries and were diffused throughout the soil mass in the modern surface soils the migrational cas have almost disappeared and the segregational cas have the largest halos of recrystallised carbonates the values of 13c for cas in the soils buried 5000 and 3800 4000 bp were lighter than in the soils buried 1600 1700 bp and the modern surface soils 10 6 to 9 9 and 9 6 to 8 8 respectively we conclude that the climate of the region during the second half of the holocene changed from relatively dry and warm in the atlantic period 5000 bp to more humid and cooler in the early subboreal 5000 4000 bp since 4000 bp the climatic conditions have remained relatively stable with some changes in moisture regime resulting from human activities in recent centuries

preparation and characterization of bone and tooth collagen for isotopic analysis abstract criteria are presented for the identification of diagenetic alteration of carbon and nitrogen isotope ratios of bone and tooth collagen prepared by a widely used method measurements of collagen concentrations in tooth and bone atomic c n ratios and carbon and nitrogen concentrations in collagen of 359 historic and prehistoric african humans and modern and prehistoric east african non human mammals are described carbon isotope ratios of collagen lipids from four bones are also presented compared to bone whole teeth have significantly lower collagen concentrations lower carbon and nitrogen concentrations in collagen and similar c n ratios carbon and nitrogen concentrations and c n ratios are relatively constant over a wide range of collagen concentrations however prehistoric specimens with very low collagen concentrations have highly variable c n ratios very low carbon and nitrogen concentrations in collagen and stable carbon and nitrogen isotope ratios unlike collagen at the transition from well preserved to poorly preserved collagen the most reliable indicator of collagen preservation is the concentration of carbon and nitrogen in collagen concentrations of c and n drop abruptly by an order of magnitude at this transition point these attributes provide simple criteria for assessing sample quality since collagen preservation can vary greatly within prehistoric sites these attributes should be reported for each specimen use of purification procedures that remove acid and base soluble contaminants and particulate matter carbonates fulvic acids lipids humic acids sediments and rootlets are recommended wider adoption of these procedures would insure comparability of results between laboratories and permit independent and objective evaluation of sample preservation and more precise dietary climatic and habitat interpretations of collagen isotopic analyses

a crustal model for the eastern alps region and a new moho map in southeastern europe in the last two decades south central europe and the eastern alps have been widely explored by many seismic refraction experiments e g celebration 2000 alp 2002 sudetes 2003 although quite detailed images are available along linear profiles a comprehensive three dimensional crustal model of the region is still missing this limitation makes this region a weak spot in continental wide comprehensive representations of crustal structure to improve on this situation we select and collect 37 published active source seismic lines in this region after geo referencing each line we sample them along vertical profiles every 50 km or less along the line and derive p wave velocities in a stack of homogeneous layers separated by discontinuities depth of crystalline basement top of lower crust and moho we finally merge the information using geostatistical methods and infer s wave velocity and density using empirical scaling relations we present here the resulting crustal model for a region encompassing the eastern alps dinarides pannonian basin western carpathians and bohemian massif covering the region within 45 circ text 51 circ hbox n and 11 circ text 22 circ hbox e with a resolution of 0 2 circ times 0 2 circ we are also able to extend and update the map of moho depth in a wider region within 35 circ text 51 circ hbox n and 12 circ text 45 circ hbox e gathering moho values from the collected seismic lines other published dataset and using the european plate reference epcrust as a background all the digitized profiles and the resulting model are available online

the structure and evolution of the western mediterranean ridge the mediterranean ridge is a unique accretionary complex consisting of five key elements the frontal slope the upper slope the crest of the ridge the cleft area and the inner plateau the imerse data show that these correspond roughly to the locus of frontal accretion of underplating of a pre messinian wedge of complex faulting and possible strike slip tectonics and of a backstop of hellenic nappes covered by a messinian forearc basin the frontal portion of the complex is a post messinian accretionary wedge composed of messinian evaporites and overlying tightly folded plio quaternary sediments underlain by pre messinian sequences attached to the african plate the basal detachment at the front of the wedge occurs at the base of the evaporites moving further to the northeast the upper slope the basal detachment cuts to deeper levels leading to the development of duplex structures where pre messinian units are subcreted beneath the messinian evaporites just behind the subcreted units the evaporites thin and may be absent on the crest of the ridge this region we interpret as the site of a pre messinian accretionary wedge we suggest that following the deposition of thick evaporites in the messinian the pre messinian accretionary tectonics continued as subsurface accretion subcretion beneath the evaporites although the crest of the ridge is largely devoid of evaporites local deep evaporite basins observed here formed as local closed basins on top of the pre messinian wedge we infer that the messinian sealevel was at about the level of the ridge crest that is 3000 m below present allowing for isostatic adjustment to the removal of the water load this would imply a sealevel drop of at least 2000 m the cleft basins mark the northeast limit of the accretionary complex thick evaporite deposits to the northeast beneath the inner plateau may have been deposited in a messinian forearc basin the evaporites of the inner plateau are underlain by a thin pre messinian sequence and by crystalline basement of the hellenic nappes this basement forms the backstop to the accretionary complex

study of the crustal thickness and the subducting lithosphere in greece from gravity data the area of greece has experienced a complex tectonic history dominated by the subduction of the african plate beneath eurasia in this study the variations of the crustal thickness in the area of greece were obtained by means of the multiple source werner deconvolution mswd method applied to gravity data thicknesses of 40 49 km are estimated beneath the hellenides mountain belt to the west eastward thinning of the crust to thicknesses ranging from 25 km in the north to 30 km in the south is seen in the aegean region these results are in good agreement with recent seismological results demonstrating that the mswd method successfully treated the problem using the crustal model we derived we computed the gravity effect of the crust and extracted it from the bouguer anomaly we also extracted the gravity effect of the subducting lithosphere from the bouguer anomaly producing a residual map where most of the original gravity variation has been successfully removed the remaining anomalies appear related to near surface features and an area of low velocity mantle in the central aegean sea

the moho depth map of the european plate summary the european plate has a 4 5 gy long and complex tectonic history this is reflected in the present day large scale crustal structures a new digital moho depth map is compiled from more than 250 data sets of individual seismic profiles 3 d models obtained by body and surface waves receiver function results and maps of seismic and or gravity data compilations we have compiled the first digital high resolution map of the moho depth for the whole european plate extending from the mid atlantic ridge in the west to the ural mountains in the east and from the mediterranean sea in the south to the barents sea and spitsbergen in the arctic in the north in general three large domains within the european plate crust are visible the oldest archean and proterozoic crust has a thickness of 40 60 km the continental variscan and alpine crust has a thickness of 20 40 km and the youngest oceanic atlantic crust has a thickness of 10 20 km

gravity modelling of the hellenic subduction zone a regional study abstract the hellenic subduction zone is clearly expressed in the arc shaped distribution of earthquake epicenters and gravity anomalies which connect the peloponnesos with crete and anatolia in this region oceanic crust of the african plate collides northward with continental crust of the aegean microplate which itself is pushed apart to the south west by the anatolian plate and at the same time is characterised by crustal extension the result is an overall collision rate of up to 4 cm year and a retreating subduction process recent passive and active seismic studies on and around crete gave first but not in all details consistent structural results useful for supporting gravity modelling this was undertaken with the aim of presenting the first 3d density structure of the entire subduction zone gravity interpretation was based on a bouguer map newly compiled using data from land marine and satellite sources the anomalies range from 170 mgal cretan sea to 10 mgal mediterranean ridge 3d gravity modelling was done applying the modelling software igmas the computed bouguer map fits the low frequency part of the observed one which is controlled by variations in moho depth less than 20 km below the cretan sea and extending 30 km below crete and the extremely thick sedimentary cover partly up to 18 km of the mediterranean ridge the southernmost edge of the eurasian plate with its more triangular shaped backstop area was traced south off crete only 50 to 100 km further to the south the edge of the african continent was traced as well in between these boundaries there is african oceanic crust which has a clear arc shaped detachment line situated at the eurasian continental edge the subduction arc is open towards the north its slab separates hotter mantle material lower density below the updoming moho of the cretan sea from colder one higher density in the south subjacent to the upper continental crust of crete is a thickened layer of lower crust followed by the subducted oceanic crust with some mantle material as intermediate layer the depth of the oceanic moho below crete is 50 km the presence and structure of subducted or underplated sediments remains uncertain

quaternary marine terraces as indicators of neotectonic activity of the ierapetra normal fault se crete greece abstract along the southern coast of the island of crete a series of east west oriented late pleistocene marine terraces exist demonstrating the significant coastal uplift of this area five uplifted terraces were mapped in detail and correlated with middle late pleistocene sea level stands following the global sea level fluctuations these terraces are deformed by the vertical movements of the nne ssw trending and dipping west ierapetra normal fault the elevation of the inner edges of the terraces was estimated at several sites by using aerial photographs and detailed topographic maps and diagrams supported by extensive field observations in this way detailed geomorphological maps were constructed utilizing gis technology all these allowed us to obtain rates of 0 3 mm yr for the regional component of uplift and 0 1 mm yr for the vertical slip movements of the ierapetra fault based on the obtained rates and the existence of coastal archaeological roman ruins it is concluded that ierapetra fault should have been reactivated sometime after the roman period

gravity data inversion for moho depth modeling in the hellenic area the main objective of this study is the determination of the moho discontinuity in the hellenic area based on gravity data inversion high resolution 2 arcmin and accuracy 2 to 3 mgal gravity data were used in the computations following the parker oldenburg iterative method and a low pass filter was applied to gravity information towards the convergence of the final solution to determine the cut off wavenumber of the filter we tested different mean depths and density contrasts of the crust and the mantle mohorovicic discontinuity the selected density contrast and mean depth of the mohorovicic discontinuity are those which agree with the moho depth interpreted from deep seismic imaging data by comparing the moho depth estimated covering both land and marine areas and including the ionian and aegean sea with those interpreted from previous studies it is shown that our solution is consistent with the available seismic data interpretation moreover the resolution of the gravity data and the appropriate filtering used in this study contributed to the representation of local features of the moho discontinuity finally area dependent discrepancies detected between the moho depths of the current solution and those derived from previous studies are extensively discussed

social differentiation and land use at an early iron age princely seat bioarchaeological investigations at the glauberg germany excavations at the late hallstatt early la tene 6th 4th century bc princely seat of the glauberg hesse germany revealed exceptionally furnished graves in monumental mounds simple inhumations in associated ditches and non normative burials of up to eight individuals in conical storage pits the study presented here addresses bioarchaeological characteristics of these burials and their implications for social differentiation and the sphere of influence of the princely seat it includes osteological adna and multi isotope analyses of 27 human individuals and faunal remains one of the outstandingly rich graves tumulus 1 grave 1 contained the skeleton of a young man the prince who consumed a superior diet based on c3 plants that also included considerable amounts of animal protein the oxygen isotope composition of his enamel is characteristic for the study area while the strontium isotope data reflect connections beyond the near environs of the princely seat and a conceivable non local origin the individuals in the conical pits had numerous joint lesions indicating a strenuous lifestyle they lack evidence for maternal relationships and differ from the prince and other iron age burials due to substantial millet consumption and rather low shares of animal protein their heterogeneous strontium isotope ratios suggest connections to the western wetterau area where settlements may have formed the economic hinterland of the glauberg hillfort the results reflect both the role of the princely seat in the wider regional context and early iron age social complexity

the crust of the western mediterranean ridge from deep seismic data and gravity modelling summary we present a crustal cross section of the western mediterranean ridge from the african margin to the aegean sea constrained by the morphology of the ridge new seismic reflection and refraction results obtained during a two ship cruise performed in december 1988 pasiphae cruise the distribution of seismicity and gravity modelling morphologically the western mediterranean ridge can be divided into three main units from the sirte abyssal plain to the hellenic trench a broad outer unit a narrow central unit and an inner unit the seismic front orgeaward extent of the interplate seismicity between the african lithosphere and the cretan arc is located 50 km seaward of the hellenic trench seismicity is thus distributed widely over the innermost unit of the ridge suggesting that brittle material is present at shallow depth beneath the inner portion of the mediterranean ridge the refraction results of the pasiphae cruise show that the crust in the ionian basin and beneath the outer and central units of the western mediterranean ridge is oceanic and that the moho discontinuity progressively deepens towards the hellenic arc in agreement with the accretionary prism model high velocity material occurs at shallow depth beneath the innermost unit of the ridge gravity modelling also indicates a significant increase in density beneath the inner unit we consequently interpret the inner unit of the ridge as the backstop of the western mediterranean ridge prism possibly composed of peloponnesus thrust sheets

the african plate a history of oceanic crust accretion and subduction since the jurassic we present a model for the jurassic to present evolution of plate boundaries and oceanic crust of the african plate based on updated interpretation of magnetic gravity and other geological and geophysical data sets location of continent ocean boundaries and age and geometry of old oceanic crust jurassic and cretaceous are updated in the light of new data and models of passive margin formation a new set of oceanic palaeo age grid models constitutes the basis for estimating the dynamics of oceanic crust through time and can be used as input for quantifying the plate boundary forces that contributed to the african plate palaeo stresses and may have influenced the evolution of intracontinental sedimentary basins as a case study we compute a simple model of palaeo stress for the late cretaceous time in order to assess how ridge push slab pull and horizontal mantle drag might have influenced the continental african plate we note that the changes in length of various plate boundaries especially trenches do not correlate well with absolute plate motion but variations in the mean oceanic crust age seem to be reflected in acceleration or deceleration of the mean absolute plate velocity

hydro physical characterization of contrasting soils in a semiarid zone of the ebro river valley ne spain summary the arid agricultural lands of the monegros desert in the central ebro basin ne spain show contrasting white patches wps and dark patches dps evidencing their different soil composition the white patches have shallow soils with low or nil crop development in most years soil at the dark patches uses to be deeper and winter cereal attains better development this paper analyzes soil hydro physical features in order to identify differences in soil physical properties between white and dark soils for this purpose 20 pairs of wp dp soils were studied on several agricultural plots each sampled pair was under the same soil condition three soil treatment st were studied freshly tilled soil mb cropped c and fallowed soil f the gypsum and calcium carbonate content organic matter om content and particle size distribution for the 0 10 cm depth soil were determined field measurements for the 1 10 cm depth soil layer were soil bulk density b soil penetration resistance spr saturated hydraulic conductivity k 1 10 and sorptivity s 1 10 the water retention curve wrc was determined in the lab on undisturbed soil cores for the 1 10 cm depth soil layer additional field measurements of soil surface crust sorptivity s crust and hydraulic conductivity k crust at saturation were also performed the results show that wp soils have significantly p b k and s values in both the surface crust and the 0 10 cm depth soil layer on average k 1 10 in dp was 1 4 times higher than that measured in wp dp showed a better defined microstructure and retained more water retention at near saturation conditions than wp soil treatments have a significant effect on b spr s 1 10 k 1 10 and on the wrc parameters overall b and spr was the lowest under mb with maximal s 1 10 and k 1 10 values under c compared to c and f mb presented the highest volume of structural porosity and the lowest water retention at near saturation conditions

accretion structural style and syn contractional sedimentation in the eastern mediterranean sea we analyse four multichannel seismic profiles collected by ogs from 1971 to 1979 along the outer part of the mediterranean ridge accretionary complex in order to understand the nature of the deformation affecting african plate sediments as they approach the africa europe plate boundary tectonic style as revealed by our data and previous studies varies considerably along the plate boundary and this variation suggests the division of the margin in three provinces characterised by different structural patterns and deformation rates 1 near orthogonal terminal subduction initial collision ionian and sirte foredeeps 2 incipient continental collision collision of continental promontories of the african margin off the cyrenaica peninsula 3 oblique terminal subduction initial collision herodotus foredeep this work aims to relate the tectonic features revealed by the seismic profiles to the geodynamic and stratigraphic parameters of the convergent margin these are essentially related to the geometry of subduction rate of convergence and obliquity and to the lithology of the incoming sedimentary section as well as the accumulation rate in the foredeep in the sirte province accumulation rate in the foredeep is relatively low and deformation is related to thrusting and folding which accounts for sediment shortening and uplift at the outer deformation front in the provinces of oblique terminal subduction the rate of normal convergence is lower the sedimentary section is thicker and the foredeep fed by the nile river has an higher syn tectonic sedimentation rate here deformation produces a broad band of large wavelength and high amplitude folds folding in this area is produced both by plate convergence related shortening and by movement of salt triggered by differential loading of the prograding nile deep sea fan in the area of incipient continental collision the foredeep is a v shaped trough as the abyssal plain has been completely subducted and the folded sediments of the accretionary complex rest directly on the african continental slope such differences in structural style are explained by great differences in strain rate that in the herodotus foredeep province has been calculated as at least four times weaker than in the western sector two factors contribute to decrease strain rate syn contractional accumulation and normal component of the effective convergence rate the former increases from west to east and possibly causes overpressuring on the decollement level salt mobilisation landward and seaward vergent folding and a very low surface taper in the herodotus foredeep the latter decreases from west to east and favours thrusting in the western sector

two ship deep seismic soundings in the basins of the eastern mediterranean sea pasiphae cruise summary new results from a two ship refraction and oblique reflection deep seismic cruise are presented to discuss the nature of the crust in the ionian sirte and herodotus abyssal plains these expanding spread profiles were processed and analysed in both the x t and p domains arrival times of reflected and refracted branches are matched by ray tracing in both domains in spite of a shallow evaporitic sequence messinian evaporites deposited on top of a thick sedimentary pile responsible for velocity inversions on many profiles we obtain excellent velocity control down to moho depth pmp and pn 8 4 8 6 km s 1 arrivals are observed the three basins have a relatively thin crust 8 to 11 km overlain by a thick sedimentary cover up to 10km in the herodotus abyssal plain the moho boundary and main crustal units identified in the basins can be followed beneath the calabrian prism to the west and beneath the mediterranean ridge to the east the crustal structure is of oceanic type for both the ionian and sirte basins where typical oceanic layer 2 and 3 are recognized the thin crust of the herodotus basin may be interpreted either as oceanic or thinned continental crust about 10 km thick the top of the crust of the herodotus basin is much deeper therefore the herodotus basin is probably significantly older than the ionian basin triassic versus early cretaceous in age

global positioning system constraints on plate kinematics and dynamics in the eastern mediterranean and caucasus we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1997 at 189 sites extending east west from the caucasus mountains to the adriatic sea and north south from the southern edge of the eurasian plate to the northern edge of the african plate sites on the northern arabian platform move 18 2 mm yr at n25 5 w relative to eurasia less than the nuvel 1a circuit closure rate 25 1 mm yr at n21 7 w preliminary motion estimates 1994 1997 for stations located in egypt on the northeastern part of africa show northward motion at 5 6 2 mm yr also slower than nuvel ia estimates 10 1 mm yr at n2 4 e eastern turkey is characterized by distributed deformation while central turkey is characterized by coherent plate motion internal deformation of 2 mm yr involving westward displacement and counterclockwise rotation of the anatolian plate the anatolian plate is de coupled from eurasia along the right lateral strike slip north anatolian fault naf we derive a best fitting euler vector for anatolia eurasia motion of 30 7 0 8 n 32 6 0 4 e 1 2 0 1 myr the euler vector gives an upper bound for naf slip rate of 24 1 mm yr we determine a preliminary gps arabia anatolia euler vector of 32 9 1 2 n 40 3 1 1 e 0 8 0 2 myr and an upper bound on left lateral slip on the east anatolian fault eaf of 9 1 mm yr the central and southern aegean is characterized by coherent motion internal deformation of 2 mm yr toward the sw at 30 1 mm yr relative to eurasia stations in the se aegean deviate significantly from the overall motion of the southern aegean showing increasing velocities toward the trench and reaching 10 1 mm yr relative to the southern aegean as a whole

the strain rate field in the eastern mediterranean region estimated by repeated gps measurements we use the combined gps velocity field of the eastern mediterranean for the period 1988 to 1996 to determine crustal deformation strain rates in a region comprising the hellenic arc the aegean sea and western anatolia we interpret the velocity field and determine the strain rate tensor by the spatial derivatives of the collocated motion vectors the region following the line marmara sea north aegean trough northern central greece and the central ionian islands is associated with strong right lateral shear motion with maximum shear strain rates of 180 nano strain a 180 10 9 a in the central aegean sea n s oriented extensional processes prevail reaching 100 nano strain a the southern aegean is characterized by relatively small strain rates maximum extensional components of the strain rate tensor reaching 150 nano strain a in a n s direction are found in central greece the hellenic arc is associated with moderate arc parallel extension and strong compression perpendicular to it projections of the strain rates parallel to the major fault zones reveal that the northern aegean is governed by the westward continuation of the north anatolian fault zone which is associated with strong dextral shearing maximum 220 nano strain a accompanied by numerous large earthquakes in this century

gravity instruments past present future geophysicists and geodesists have traditionally demanded high levels of accuracy from gravity sensors to make notoriously difficult measurements of extremely small differences in the earth s gravity field the earth s gravity field ranges from about 983 000 mgal at the poles to about 978 000 mgal at the equator yet we demand accuracies in the range of less than 1 mgal for typical surface measured exploration targets this means resolution of 1 part per million compared with the earth s gravitational field

greek tectonics and seismicity abstract the validity of existing tectonic models for the area of greece is examined in the light of the new recalculated parameters for earthquakes of the region makropoulos and burton 1981 relocated hypocentral positions are extracted from the catalogue to form radial and vertical distance depth cross sections centred on a reference point near the mid point of the aegean volcanic arc and these are used to form a three dimensional topography of the base of earthquake occurrence below 60 km isodepth maps are extracted from this topography as both three and two dimensional map presentations these maps reveal several significant features of deep seated tectonic processes in the region isodepths exceeding 150 km are seen in the northwest aegean and these are more closely linked to the sporadhes and gulf of thermaicos rather than the north aegean trough the 150 km isodepths are also seen in the northeast aegean straddling the dardanelles in the northeastern part of the peloponnesus gulf of saronikos and eastern gulf of corinth in the southern peloponnesus towards crete and extending from north of kos to south of rodos the largest extent of deepest activity is seen south of rodos and this continues towards southwest of turkey the subduction zone of the hellenic arc is clear but smooth benioff zones are not the norm and these data show that structural complexity is more readily observed it is concluded that none of the proposed tectonic models completely explain the observed activity over the whole area and rather than propose yet another model places where further work is still particularly necessary are identified

a 3 d density velocity model between the cretan sea and libya abstract a 3 d density model for the cretan and libyan seas and crete was developed by gravity modelling constrained by five 2 d seismic lines velocity values of these cross sections were used to obtain the initial densities using the nafe drake and birch empirical functions for the sediments the crust and the upper mantle the crust outside the cretan arc is 18 to 24 km thick including 10 to 14 km thick sediments the crust below central crete at its thickest section has values between 32 and 34 km consisting of continental crust of the aegean microplate which is thickened by the subducted oceanic plate below the cretan arc the oceanic lithosphere is decoupled from the continental along a nw se striking front between eastern crete and the island of kythera south of peloponnese it plunges steeply below the southern aegean sea and is probably associated with the present volcanic activity of the southern aegean sea in agreement with published seismological observations of intermediate seismicity low density and velocity upper mantle below the cretan sea with 3 25 103 kg m3 and vp velocity of compressional waves around 7 7 km s which are also in agreement with observed high heat flow density values point out at the mobilization of the upper mantle material here outside the hellenic arc the upper mantle density and velocity are 3 32 103 kg m3 and vp 8 0 km s respectively the crust below the cretan sea is thin continental of 15 to 20 km thickness including 3 to 4 km of sediments thick accumulations of sediments located to the ssw and sse of crete are separated by a block of continental crust extended for more than 100 km south of central crete these deep sedimentary basins are located on the oceanic crust backstopped by the continental crust of the aegean microplate the stretched continental margin of africa north of cyrenaica and the abruptly terminated continental aegean microplate south of crete are separated by oceanic lithosphere of only 60 to 80 km width at their closest proximity to the east and west the areas are floored by oceanic lithosphere which rapidly widens towards the herodotus abyssal plain and the deep ionian basin of the central mediterranean sea crustal shortening between the continental margins of the aegean microplate and cyrenaica of north africa influence the deformation of the sediments of the mediterranean ridge that has been divided in an internal and external zone the continental margin of cyrenaica extends for more than 80 km to the north of the african coast in form of a huge ramp while that of the aegean microplate is abruptly truncated by very steep fractures towards the mediterranean ridge changes in the deformation style of the sediments express differences of the tectonic processes that control them that is subduction to the northeast and crustal subsidence to the south of crete strike slip movement between crete and libya is required by seismological observations

an integrated gravity model for europe s crust and upper mantle we present an integrated gravity model of the european lithosphere based on an analysis of a number of new data sets leading to a much higher resolution than provided by previous models first of all a recent crustal model eucrust 07 is used to quantify the crustal contribution to the observed gravity field and to identify the effect of mantle heterogeneity the new gravity field model is based on a combination of satellite champ and grace and terrestrial data we also use these data sets to estimate residual mantle gravity anomalies and residual topography reflecting the effect of mantle density variations induced by temperature and compositional heterogeneity the separation of these effects is vital for a proper assessment of mantle structure and evolution in addition we utilize a new tomographic model for p and s velocity anomalies beneath europe which is a priori corrected for crustal structure using eucrust 07 the seismic velocity anomalies were subsequently converted into temperature anomalies using a mineral physics approach we estimate the effect of temperature variations on the gravity field and subtract it from the total mantle field the residual fields point to an important role of compositional density anomalies in the upper mantle a number of key features of the compositional density distribution so far invisible in seismic tomography data are detected for the first time

geodetic determination of the kinematics of central greece with respect to europe implications for eastern mediterranean tectonics we use a new satellite laser ranging global positioning system slr gps solution at seven sites in anatolia and aegea to obtain a better definition of the extrusion motion of the anatolian aegean block with respect to europe we show that this motion can be described in a first approximation by a counterclockwise rotation which transfers most of the motion of arabia to anatolia we combine 78 displacement vectors obtained at common points of two triangulation nets measured in central greece in 1895 and 1975 with the slr gps measurements to compute the velocity field over greece with respect to europe these measurements indicate that central greece is a zone of extension between the anatolian aegean counterclockwise rotation to the south and the northern greece clockwise rotation to the north this extension is principally localized within the gulf of corinth to the east but is distributed to the west we then extrapolate this velocity field to the whole aegea and western anatolia using recently published gps results as well as the slr results the narrow dextral north anatolian fault which limits the velocity field to the north progressively gives way to a much wider boundary zone where extension becomes dominant we show that the collision between the mediterranean ridge and africa began 3 6 ma and we describe the modifications that this collision has produced on the kinematic pattern both in aegea and on the mediterranean ridge