early pleistocene climate changes in the central mediterranean region as inferred from integrated pollen and planktonic foraminiferal stable isotope analyses vegetation inherited from a pliocene subtropical climate evolved through obliquity oscillations and global cooling leading to modern conditions an integrated highly time resolved record of pollen and stable isotopes 18o and 13c of globigerina bulloides was obtained to understand vegetation responses to early pleistocene climate changes continental and marine responses are compared in the central mediterranean region with a particular consideration of environmental changes during anoxic events pollen data illustrate vegetation dynamics as follows 1 development of mesothermic elements warm and humid conditions 2 expansion of mid and high altitude elements cooler but still humid conditions and 3 strengthening of steppe and herb elements cooler and dry conditions these successions correlate with precession 18o variations recorded by globigerina bulloides define two cycles mis 43 40 related to obliquity at northern low to mid latitudes the pollen signal records temperature and wetness changes related to precession even during global climate changes induced by obliquity this may result in unexpected increasing wetness during glacial periods which has to be considered specific to the central and eastern mediterranean region lastly an analysis of anoxic events reveals that enhanced runoff is indicated by increasing frequency of the riparian trees liquidambar and zelkova

discrete plio pleistocene phases of tilting and counterclockwise rotation in the southeastern aegean arc rhodos greece early pliocene formation of the south aegean left lateral strike slip system the island of rhodos represents an uplifted block in the largely submerged southeastern aegean forearc it has a complex history of subsidence uplift and counterclockwise rotation during the plio pleistocene in response to the interplay between large scale geodynamic processes in this paper we present a new chronostratigraphic framework for the continental pliocene apolakkia basin of southwestern rhodos we combine these time constraints with recently published chronostratigraphic data from the marine plio pleistocene basins of northeastern rhodos to reconstruct rotational and vertical motions our palaeomagnetic results identify two rotation phases for rhodos c 10 9 6 counterclockwise ccw rotation between 3 8 and 3 6 ma and c 17 6 ccw rotation since 0 8 ma between these phases rhodos tilted to the se drowning the southeastern coast to a depth of 500 600 m between 2 5 and 1 8 ma then to the nw which resulted in the re emergence of the drowned relief between 1 5 and 1 1 ma we relate the rotations of rhodos to incipient formation of the south aegean sinistral strike slip system and the foundering of the rhodos basin the previously shown absence of messinian evaporites in the deep marine rhodos basin in combination with the 3 8 ma onset of ccw rotation of rhodos constrains the onset of the formation of the south aegean strike slip system between 5 3 and 3 8 ma the formation of this strike slip system is probably related to the interplay of oblique collision between the southeastern aegean region and the northward moving african plate the westward motion of anatolia gravitational spreading of the overthickened aegean lithosphere and the recently postulated southwestward retreat of the african subducted slab along a subduction transform edge propagator fault

paleoenvironmental changes at the lower pleistocene montalbano jonico section southern italy global versus regional signals abstract integrated high resolution data from calcareous plankton assemblages foraminifera and nannofossils together with geochemical and mineralogical investigations have been collected at the on land montalbano jonico section southern italy in order to reconstruct the paleoenvironmental changes through marine isotope stages mis 23 37 time series analysis on globigerina bulloides and cassidulina carinata 18o records and on selected calcareous plankton proxies mainly revealed the occurrence of precession and obliquity forcing the deposition of sapropel layers which are interbedded in the montalbano jonico section was driven by water column stratification insolation cycle i 104 and enhanced sea surface water productivity insolation cycle i 112 i 102 and i 86 different paleoenvironmental conditions mark the sedimentary evolution of the section from 1240 to 1082 ka mis 37 mis 32 high percentage abundances of warm and oligotrophic planktonic foraminifera and calcareous nannofossil taxa indicate the establishment of oligotrophic and stratified surface water conditions a key paleoenvironmental change occurred during mis 31 from about 1080 to 1065 ka which was a very warm interglacial characterized by an increase of tropical subtropical globigerinoides ruber group and globigerinoides trilobus and low salinity braarudosphaera bigelowii sea surface water taxa during this interval more humid climate conditions coupled with changes in local paleomorphology may have triggered a higher and unusual freshwater input and the creation of a new entry point for sediment supply into the basin from a different drainage area from about 1065 to 1010 ka mis 30 mis 29 a cool and dry climate prevailed in the circum mediterranean area during a time of precession maxima this favored lowered sea surface temperatures and an increase of polar water neogloboquadrina pachyderma left coiling there are also indications of a reduction of the terrigenous input from the new source area from 1010 ka upward mis 28 mis 23 the higher abundances of globigerina bulloides turborotalita quinqueloba and calciosolenia spp indicate enhanced productivity conditions probably related to high turbidity of sea surface waters triggered by a more conspicuous sediment input from land analysis of the long term trends in the multiproxy patterns suggests that the major paleoenvironmental changes occurred as a consequence of the combined effect of orbitally controlled global climate and regional processes

stable isotope anomalies in mediterranean pleistocene records oxygen and carbon isotope records of twelve mediterranean cores raised from west alboran sea to east off israel and of four atlantic cores raised from the western side of gibraltar and located respectively inside below and beyond the modern mediterranean outflow are compared to open ocean records of core 71 139c from the north atlantic and core v19 30 from the east pacific oxygen isotope stratigraphies can be established for deep mediterranean records and the major events of the last 150 ka are easily identifiable for instance the five substages of stage 5 or the 18 ka event stage 2 are identified but the 10 ka event younger dryas is only recorded by globigerina bulloides and benthic foraminifera suggesting that the cooling affected only winter sst 14c dates for the two terminations ia and ib of the last deglaciation which are recorded in sediment cores from areas with high sedimentation rates faro ridge alboran sea sicilian strait are in good agreement with the dates published for the same termination in atlantic cores an intermediate step however has been identified in some cores at 14 ka and divides termination ia into two phases oxygen isotope anomalies are recorded by the shallow water species globigerinoides ruber they correspond to 1 a higher amplitude glacial interglacial change in 18o values which exceeds that of the open ocean by 1 in the western basin and by 1 7 in the eastern basin 2 large isotopic depletions during the deposition of sapropel s1 s3 and s5 they are interpreted as the result of fresh water run off responsible for a strong dilution in the shallower layers of the east mediterranean waters the isotopic effect of this dilution averages 0 75 for sapropel s1 and 1 6 for sapropel s5 during the last glacial maximum the mediterranean still acted as a concentration basin and a gradient of 18o values similar to the modern one 0 75 existed from west to east in the deep waters apparently deep water temperatures were lower during the last glacial but the decrease did not exceed 4 c in the eastern basin major anomalies are also contained in the 13c records of g bulloides and benthic foraminifera the 13c records from surface intermediate and deep waters of the eastern basin and from intermediate and deep waters of the western basin are opposite to that of the open ocean during glacial time 13c values were higher in intermediate and deep waters of the whole mediterranean and also in surface water of the eastern basin at the same time the 13c gradient of surface to deep waters was low this gradient increased during the last deglaciation while 13c values of g bulloides and benthic foraminifera decreased this decrease interrupted at 10 ka may have been related to increased fresh water run off from the bordering contintents due to increased precipitation especially in the tropical belt the 13c depletion is clearly recorded in the levantine and deep water masses and can be traced westward in the mediterranean outflow oxygen and carbon isotope anomalies recorded simultaneously in the east mediterranean by the shallow water species globigerinoides ruber during sapropel deposition indicate that increased precipitation on the bordering continents and strong fresh water run off during the time of the last deglaciation may have caused a density stratification and deep stagnation in the eastern basin uncertainties arise from the fact that in the mixing model deglacial mediterranean waters are mixed with continental fresh waters the isotopic characteristics of which are not entirely understood although increased surface water production of biogenic material can not be excluded as a possible cause of 13c depletion it appears that the river discharge including the nile as well as black sea input are also plausible sources for the fresh water layering

distribution patterns of live planktic foraminifers as related to regional hydrography and productive systems of the mediterranean sea abstract distribution patterns of live planktic foraminifers are examined at two times of the year late summer and late winter through horizontal plankton towing along a nw se transect across the west and east mediterranean basins and in the alboran sea french oceanographic cruises vicomed i ii and iii respectively foraminiferal production is significantly different in the two sampling periods and across the west and east mediterranean foraminiferal density is higher in winter than summer e g in the western basin 3700 specimens 1000 m3 in winter against 200 600 specimens 1000 m3 in summer the production averaged for the two sampling sets is higher in the western basin than in the eastern one however in late summer peaks of maximal production are observed in the central mediterranean strait of sicily and ionian basin 1000 to 2000 specimens 1000 m3 where the assemblages are dominated by globigerinoides ruber rosea and g ruber alba in the mediterranean sea frontal regions and semipermanent eddies which are essentially controlled by regional hydrography represent a significant portion of the regional production they also elicit a higher diversity of species their influence is observed in summer as well as in winter at the end of summer the rather shallow mixed layer hosts spinose symbiont bearing species such as g ruber alba g ruber rosea o universa and g trilobus at that season in the western basin the nutrient content of the mixed layer is generally low and the surface layer is rapidly nutrient depleted summer foraminiferal production remains low at the surface with respect to the winter production in the eastern basin late summer and autumn correspond to the biological spring summer foraminiferal production in surface waters is higher than in winter but standing crops are lower than in the western basin for the same species at the same period in summer however frontal structures and eddies are generally better developed than in winter in some particular cases frontal boundaries in the western basin eddies south of cyprus nutrients from intermediate layers can be upwelled through isopycnal or diapycnal mixing to the photic zone and allow for secondary blooms in the western basin these blooms favour the development of grazers at depth globorotalia truncatulinoides g inflata south of cyprus in the eastern basin oligotrophic conditions promote the development of heterotrophic organisms and predatory foraminifers have higher standing stocks g ruber alba g ruber rosea in winter the break down of the thermocline combined with deep turbulent mixing in the northwestern basin and the deepening of the mixed layer in the alboran sea and along the north african coast result in increased phytoplankton biomass and favour reproduction and proliferation of species such as g truncatulinoides or g inflata our observations indicate that the geographic and depth distribution of live foraminiferal species cannot be entirely explained by the general temperature and salinity differences among the different mediterranean basins but that they are strongly related to regional hydrographic patterns hydrography controls the seasonality and depth of the turbulent mixing which differ between the western and the eastern basins the depth of the mixed layer and its seasonal stratification and the strength of the pycnocline nutrient supply and primary production are mostly regulated by these dynamics one may therefore expect that the species assemblages on the sea floor and in deep sea cores will also correlate to the various hydrographic parameters of the overlying water masses

the 2 look tops mode design and demonstration with terrasar x burst mode acquisition schemes achieve wide coverage at the expense of a degraded azimuth resolution reducing therefore the performance on the retrieval of ground displacements in the azimuth direction when interferometric acquisitions are combined moreover the azimuth varying line of sight can induce discontinuities in the interferometric phase when local azimuth displacements are present e g due to ground deformation in this contribution we propose the interferometric 2 look terrain observation by progressive scans tops mode a sustaining innovation which records bursts of radar echoes of two separated slices of the doppler spectrum the spectral separation allows to exploit spectral diversity techniques achieving sensitivities to azimuth displacements better than with stripmap and eliminating discontinuities in the interferometric phase moreover some limitations of the tops mode to compensate ionospheric perturbations in terms of data gaps or restricted sensitivity to azimuth shifts are overcome the design of 2 look tops acquisitions will be provided taking the terrasar x system as reference to derive achievable performances the methodology for the retrieval of the azimuth displacement is exposed for the case of using pairs of images as well as for the calculation of mean azimuth velocities when working with stacks we include results with experimental terrasar x acquisitions demonstrating its applicability for both scenarios

a well established early middle pleistocene marine sequence on south east zakynthos island western greece magneto biostratigraphic constraints and palaeoclimatic implications the chronostratigraphy of a long onshore early middle pleistocene marine sedimentary sequence on the south east part of zakynthos island greece is presented correlation of the succession with the isotope record of ocean drilling program site 963 reveals the combined influence of tectonics and eustacy in this area the sequence is divided into three formations by two main unconformities that apparently relate to sea level lowstands associated with two major northern hemisphere glaciations those of marine isotope stages mis 22 and 12 the zakynthos sequence in many ways is comparable with the italian valle di manche section magnetostratigraphic and rock magnetic analyses supported by biostratigraphy document the position of the matuyama brunhes chron boundary 0 77 ma the top and base of the jaramillo subchron 0 99 1 07 ma the cobb mountain subchron 1 173 1 185 ma and the top of the olduvai subchron 1 78 ma the underlying strata are constrained exclusively by detailed nannofossil biostratigraphy extending at least to the lowermost pleistocene at around 2 54 ma and therefore certainly incorporating the base of the olduvai subchron 1 95 ma and possibly the gauss matuyama chron boundary 2 58 ma in addition a remarkable increase in sedimentation rate from 3 2 and 28 cm ka 1 to 167 cm ka 1 and hence resolution above the matuyama brunhes boundary middle pleistocene reveals one short lived magnetic excursion possibly 17a 0 66 ma within the normal polarity brunhes chron copyright 2011 john wiley sons ltd

magnetic polarity stratigraphy of pliocene pleistocene marine sediments from rhodos eastern mediterranean abstract a magnetic polarity stratigraphy extending from the end of the gilbert chron 3 5 ma into the brunhes chron 0 73 ma has been constructed from three partly overlapping sections of an 25 m thick sequence of marine pliocene pleistocene sediments of the sgourou formation rhodos the natural remanent magnetization is carried by detrital maghemite magnetite phases normal polarity magnetic overprints most likely of viscous origin were successfully removed from normal polarity zones only the secondary overprints of the reversed polarity magnetizations cannot be removed by alternating field a f demagnetization polarity zones have nevertheless been unambiguously determined by detailed analysis of the behaviour of the samples during step wise a f demagnetization the fad of hyalina baltica base of emilian occurs below the jaramillo subchron and is the only available biostratigraphic datum cytheropteron testudo pliocene pleistocene boundary is not found in undoubted specimens within this sequence on the assumption of a continuous accumulation rate a one to one correlation with the established geomagnetic polarity time scale gpts has been performed within this time frame a thin but pronounced volcanic ash layer is dated to 2 95 ma coinciding with the age of igneous activity on nearby islands k ar dated to 3 0 3 15 ma age depth relationships suggest that deposition of the sediment occurred in three distinct phases with different deposition rates and these are probably related to local tectonic events

changes in vegetation and marine environments in the eastern mediterranean rhodes greece during the early and middle pleistocene pollen records marine faunal associations and stable isotope compositions of sediments from rhodes greece have been determined to track environmental changes in the eastern mediterranean during the early and middle pleistocene a detailed chronostratigraphic curve based on magnetostratigraphic data was obtained by correlating pollen spectra with the mediterranean oxygen isotopic curve of ocean drilling program site 975 five sedimentary sequences that correspond to marine oxygen isotope stage mis 31 27 and to mis 20 17 have been investigated in the confined tsampika microbasin high amplitude pinus variations confirm glacio eustatic changes deduced from changes in marine faunal associations and sedimentary depositional environments reflecting climatic cycles identified in the marine carbonate oxygen isotope record eight vegetation successions characterized by the dominance first of mesothermic elements then of mid and high altitude elements with pinus and ending with maxima in herb and steppe elements have been documented most of them were probably driven by changes in insolation occurring in high northern latitudes obliquity impact during the late early pleistocene and early middle pleistocene

the sapropel record of the eastern mediterranean sea results of ocean drilling program leg 160 research on sediments recovered during ocean drilling leg 160 has concentrated on two issues the first concerned the stratigraphy of sapropel formation the second was oriented to clarify specific processes that explain sapropel origin progress has been made in the construction of stratigraphic composites out of sedimentary sequences from individual holes at each of the palaeoceanographic sites on the composites initial work has resulted in the establishment of high resolution and intermediate resolution stratigraphies for three sites 963 964 967 correlation of sedimentary cycles to astronomical insolation cycles extends the stratigraphies to sites 969 and 966 the sapropel occurrences in the marine and land sequences over the entire eastern mediterranean are correlated with the resolution that can be obtained from isotope studies groups of sapropels occurred simultaneously over the entire basin in detail however the temporal and facies patterns of sapropel sequences differ between individual sites and depositional basins the differences may be related to effects of water depth diagenesis and post depositional tectonic attenuation of sequences studies on the geochemistry and facies of sapropels agree that anoxic conditions favoured preservation of organic matter in sapropels caused the enrichment of trace metals associated with sapropels and helped to preserve primary sedimentary structures besides all evidence is consistent with elevated fluxes of organic matter and associated elements during sapropel events

structural architecture of the rhodes basin a deep depocentre that evolved since the pliocene at the junction of hellenic and cyprus arcs eastern mediterranean abstract interpretation of 1500 km of multi channel seismic reflection profiles shows that the rhodes basin evolved in two distinct tectonic stages a protracted miocene convergence episode p1 resulted in the development of a mainly sse verging fold thrust belt this period corresponds with the emplacement of the lycian nappes to the northeast and fold thrust complexes on the island of rhodes to the west this phase of deformation ceased in the late miocene the absence of evaporites in the rhodes basin suggests that this region must have remained above the depositional base of marine evaporite environment during the messinian the morphology of the m reflector and the architecture of the lowermost pliocene growth strata in the central portion of the rhodes basin demonstrate the existence of rugged paleo relief over the pre existing miocene fold thrust belt in early pliocene the middle pliocene quaternary phase of deformation is characterised by ne sw sinistral transpression p2 and rapid regional subsidence the p2 deformation occurred in response to an actively curving hellenic arc and the increasing obliquity of its eastern limb the pliny strabo trenches or fault zones to the convergence vector of the african plate during this time the p1 structures became re activated as transpressional faults further facilitating the rapid subsidence we envisage the evolution of the rhodes basin as the result of subsidence associated with loading of the large imbricate thrust panels that carry the western tauride mountains in the north at present the pliny strabo fault zones are delineated as a ne sw trending 30 50 km wide zone that continue into the western segment of the rhodes basin this fault zone is further correlated with the similar trending 50 km wide burdur fethiye fault zone in southwestern turkey

fossil assemblages associated with submerged beachrock beds as indicators of environmental changes in terrigenous sediments examples from the gelasian early pleistocene of rhodes greece the lower pleistocene kritika member of the rhodes formation is composed of predominantly siliciclastic deposits that are sometimes intercalated with hardbottoms formed by drowning of former beachrock beds a wide variety of sclerobionts occur in this environment very different from the poorest soft bottom populations occurring in other levels of the kritika member the most characteristic abundant and frequently diverse are the encrusting forms coralline algae bivalves serpulid worms and bryozoans numerous other groups of sessile and vagile organisms are associated with these crust forming communities a number of skeletal organisms sometimes including zooxanthellate coral colonies formed small carbonate buildups on top of several beachrock beds boring organisms also occur evidence for a two step deepening succession over the previously formed beachrock is provided by palaeontological and sedimentological data the rapidly cemented sandy conglomeratic beds were first colonised by a relatively shallow water around 20 m biocoenosis of mostly encrusting organisms another association with encrusting and erect organisms was later established in a deeper environment 20 40 m a comparison with holocene beachrock occurring on the coast of rhodes was also undertaken their submerged part provided habitat for poorer but similar biotas to those occurring in the kritika member the lower pleistocene beachrock and associated organogenic fossil assemblages indicate repeated drowning episodes during deposition of the kritika member and provide help in sequence stratigraphic interpretations of these siliciclastic deposits notably they can be used as indicators of relative sea level changes

facies associations in warm temperate siliciclastic deposits insights from early pleistocene eastern mediterranean rhodes greece diverse abundant and usually well preserved communities of skeletal organisms occur in the lower pleistocene gelasian siliciclastic deposits of the greek island of rhodes benthic foraminifers molluscs and bryozoans have been studied in four measured and sampled sections located in the northern part of the island among these bottom dwelling organisms numerous extant taxa are good environmental indicators and combined with field observations and sedimentological data they provide information on the probable conditions in which they developed the siliciclastic deposits of the kritika formation have been divided into 14 different bio and lithofacies which have been further grouped into four facies associations corresponding to four different environmental settings 1 continental to fluviatile 2 brackish water lagoonal deltaic 3 infralittoral 0 20 m and 4 upper circalittoral depths of 20 40 m but also down to c 50 60 m among the marine facies associations several characteristic biocoenoses have been recognized soft bottoms fine to coarse sands and gravels seagrass meadows biogenic calcareous crusts on drowned beachrock slabs red algal rhodoliths and bivalve shell beds in the studied sections 13 superimposed genetic sequences have been documented the repetition of similar facies associations within each sequence suggests 1 a possibly eustasy controlled cyclic sedimentation 2 a general subsidence of rhodes during the deposition of the studied facies associations and 3 a mostly constant range of environmental conditions i e sedimentation rates and temperature throughout the gelasian

drainage basin delineation for outlet glaciers of northeast greenland based on sentinel 1 ice velocities and tandem x elevations abstract the drainage divides of ice sheets separate the overall glaciated area into multiple sectors these drainage basins are essential for partitioning mass changes of the ice sheet as they specify the area over which basin specific measurements are integrated the delineation of drainage basins on ice sheets is challenging due to their gentle slopes accompanied by local terrain disturbances and complex patterns of ice movement until now in greenland the basins have been mostly delineated along the major ice divides which results in large drainage sectors containing multiple outlet glaciers however when focusing on measuring glaciological parameters of individual outlet glaciers more detailed drainage basin delineations are needed here we present for the first time a detailed and fully traceable approach that combines ice sheet wide velocity measurements by sentinel 1 and the high resolution tandem x global dem to derive individual glacier drainage basins we delineated catchments for the northeast greenland ice sheet with a modified watershed algorithm and present results for 31 drainage basins even though validation of drainage basins remains a difficult task we estimated basin probabilities from monte carlo experiments and applied the method to a variety of different ice velocity and dem datasets finding discrepancies of up to 16 in the extent of catchment areas the proposed approach has the potential to produce drainage areas for the entirety of the greenland and antarctic ice sheets

the rhodes basin a post miocene tectonic trough abstract new light is shed on the enigmatic rhodes deep marine basin by a set of underway geophysical data across it including swath bathymetry seismic reflection profiles gravity and magnetic data this deep trough as much as 4485 m to the east of the island of rhodes and close to southwestern turkey contains no messinian evaporites and only a thin pliocene quaternary sedimentary section

the fethiye burdur fault zone a component of upper plate extension of the subduction transform edge propagator fault linking hellenic and cyprus arcs eastern mediterranean abstract the hellenic and cyprus arcs that mark the convergent boundary of the african and aegean anatolian plates are offset along a subduction transform edge propagator step fault running ne sw along the pliny and strabo trenches the continuation of the fault to the northeast through the rhodes basin and into sw anatolia is assessed seismic reflection profiles show that the structural architecture of the northern sector of the rhodes basin includes a large crustal scale fold thrust belt which is overprinted by numerous faults with small extensional stratigraphic separations a protracted episode of convergence in the miocene resulted in the development of a prominent ne sw striking and nw verging fold thrust belt in the rhodes basin the absence of evaporites in the rhodes basin and several seaward prograded vertically stacked quaternary delta successions resting at 2500 3500 m water depth collectively suggest that the rhodes basin must have remained above the depositional base of marine evaporite environment during the messinian and that the region must have subsided very rapidly during the pliocene quaternary during the pliocene quaternary a ne sw trending belt developed across the rhodes basin while the structural framework of this belt was characterised by reactivated thrusts in the central portion of the basin a prominent zone of ne sw striking and nw and se dipping faults with extensional separations developed in the northern portion of the basin two seismic profiles running parallel to the present day coastline provide the much needed linkage between the fethiye burdur fault zone onland and the reactivated thrusts in central rhodes basin and show that the pliocene quaternary zone of high angle faults with extensional separations clearly link with the similarly trending and dipping strike slip faults onland in the esen valley thus providing the continuity between the pliny strabo trenches in the southwest and the fethiye burdur fault zone in the northeast mapping of many faults in parts of the fethiye burdur fault zone shows evidence for sinistral strike slip but total displacement across the fault zone is at maximum a few tens of kilometres the step fault thus appears to have diminishing displacement associated with it as it propagates upwards into the upper plate from its originating tear in the subducting plate

plio pleistocene climate evolution trends and transitions in glacial cycle dynamics abstract we describe the evolution of climate system dynamics by examining the climate response to changes in obliquity and precession over the last 5 3 myr in particular we examine changes in the shape of glacial cycles and the power of obliquity and precession response in benthic 18 o when the exponential trend in 18 o variance is removed its spectral power exhibits strong proportional responses to amplitude modulations in orbital forcing over most of the plio pleistocene precession responses correlate with modulations in forcing for the last 5 myr but 41 kyr response is sensitive to obliquity modulation only before 1 4 myr where responses are sensitive to modulations in forcing we demonstrate that glacial cycles are orbitally forced rather than being self sustained or paced by orbital changes the shapes of glacial cycles have several nonlinear properties which may be indicative of glacial interglacial differences in climate sensitivity or response time the saw tooth asymmetry of glacial cycles first appears shortly after the onset of major northern hemisphere glaciation and the relative duration of interglacial stages decreases at 1 4 myr collectively trends in the shape of glacial cycles and the sensitivity of 18 o to obliquity and precession are suggestive of major transitions in climate dynamics at approximately 2 5 and 1 4 myr but show no significant change associated with the appearance of strong 100 kyr cycles during the mid pleistocene transition

orbital variations in planktonic foraminifera assemblages from the ionian sea during the middle pleistocene transition abstract the middle pleistocene transition 1 2 0 7 ma is the most recent re organization of the global climate system which includes variations in the frequency and amplitude of glacial interglacial cycles increased ice sheet volume sea surface temperature cooling and a significant drop in the co 2 atmospheric levels here we present high resolution planktonic foraminifera data mean sampling resolution of about 780 years from core lc10 recovered in the ionian sea eastern mediterranean between 1 2 and 0 9 ma selected taxa among them g ruber t quinqueloba and g bulloides show significant periodicities that can be associated to orbital cycles mainly precession and obliquity the planktonic foraminifera based paleoclimatic curve exhibits a cooling linear trend that can be associated to similar phenomena observed in the north atlantic on the other hand we refer to the influence of the north african monsoon the occurrence of two peaks of the low salinity tolerant species g quadrilobatus that fall in coincidence of sapropel layers finally we discuss the distribution pattern of n pachyderma sinistral coiling with peaks up to about 20 between mis 30 and 28 and compare it to middle late quaternary records of the sicily channel and western mediterranean

ionospheric phase screen compensation for the sentinel 1 tops and alos 2 scansar modes variations of the ionosphere can significantly disrupt synthetic aperture radar sar acquisitions and interferometric measurements of ground deformation in this paper we show how the ionosphere can also strongly modify c band interferograms despite its smaller influence at higher frequencies thus ionospheric phase screens should not be neglected their compensation improves the estimation of ground deformation maps the split spectrum method is able to estimate the dispersive ionospheric component of the interferometric phase we describe the implementation of this method for the burst modes tops and scansar to estimate and remove ionospheric phase screens we present sentinel 1 interferograms of the 2016 taiwan earthquake and alos 2 interferograms of the 2015 nepal earthquake which show strong ionospheric phase gradients and their corrected versions finally to validate the results and better understand the origin of these ionospheric variations we compare the estimated differential ionosphere with global total electron content maps and local global positioning system measurements

paleobathymetry in the backstripping procedure correction for oxygenation effects on depth estimates abstract this paper aims to provide a straightforward and easily applicable method for estimating the depositional depth evolution of marine basins vertical movements of the basin floor can be reconstructed from the sedimentary record and more accurately constrained when information from the sedimentary history is combined with palaeodepth estimates derived from fauna to this end we propose to extend an existing method based on the percentage of planktonic foraminifera with respect to the total planktonic and benthic foraminiferal association which is expressed as the percentage planktonics p the ratio between planktonic and benthic foraminifera is related to water depth and the p generally increases with increasing distance to shore however next to water depth the oxygen level of bottom waters has a profound effect on the abundance of benthic foraminifera and as such influences the p depending on basin configuration the oxygen level at the sea floor can vary on milankovitch time scales and is reflected by the fraction of benthic foraminiferal species that indicate an effect of oxygen stress on the biotic system these species can be used as stress markers and their percentage with respect to the total benthic population is here expressed as s to assess whether the effect of sea floor oxygenation impairs depth reconstructions we studied the percentage of planktonic foraminifera p in five well dated sedimentary successions from the lower pliocene of crete corfu and milos in greece additionally we assessed whether different foraminiferal size fractions and counting methods affect the determination of the percentage of planktonic foraminifera the palaeobathymetric evolution calculated for each basin was confirmed for all successions by an independent check on depth related occurrences of benthic foraminifera after correction for bathymetry changes of the basin due to sedimentation compaction and eustatic sea level variations the vertical movement history of the basin floor was inferred we propose a standard methodology for reconstructions of palaeobathymetry of marine sedimentary successions from foraminiferal associations

insar time series estimation of the ionospheric phase delay an extension of the split range spectrum technique repeat pass interferometric synthetic aperture radar insar observations may be significantly impacted by the propagation delay of the microwave signal through the ionosphere which is commonly referred to as ionospheric delay the dispersive character of the ionosphere at microwave frequencies allows one to estimate the ionospheric delay from insar data through a split range spectrum technique here we extend the existing split range spectrum technique to insar time series we present an algorithm for estimating a time series of ionospheric phase delay that is useful for correcting insar time series of ground surface displacement or for evaluating the spatial and temporal variations of the ionosphere s total electron content tec experimental results from stacks of l band sar data acquired by the alos 1 japanese satellite show significant ionospheric phase delay equivalent to 2 m of the temporal variation of insar time series along 445 km in chile a region at low latitudes where large tec variations are common the observed delay is significantly smaller with a maximum of 10 cm over 160 km in california the estimation and correction of ionospheric delay reduces the temporal variation of the insar time series to centimeter levels in chile the ionospheric delay correction of the insar time series reveals earthquake induced ground displacement which otherwise could not be detected a comparison with independent gps time series demonstrates an order of magnitude reduction in the root mean square difference between gps and insar after correcting for ionospheric delay the results show that the presented algorithm significantly improves the accuracy of insar time series and should become a routine component of insar time series analysis

the middle pleistocene transition characteristics mechanisms and implications for long term changes in atmospheric pco2 abstract the emergence of low frequency high amplitude quasi periodic 100 kyr glacial variability during the middle pleistocene in the absence of any significant change in orbital forcing indicates a fundamental change internal to the climate system this middle pleistocene transition mpt began 1250 ka and was complete by 700 ka its onset was accompanied by decreases in sea surface temperatures ssts in the north atlantic and tropical ocean upwelling regions and by an increase in african and asian aridity and monsoonal intensity during the mpt long term average ice volume gradually increased by 50 m sea level equivalent whereas low frequency ice volume variability experienced a 100 kyr lull centered on 1000 ka followed by its reappearance 900 ka although as a broad band of power rather than a narrow persistent 100 kyr cycle additional changes at 900 ka indicate this to be an important time during the mpt beginning with an 80 kyr event of extreme sst cooling followed by the partial recovery and subsequent stabilization of long term north atlantic and tropical ocean ssts increasing southern ocean sst variability primarily associated with warmer interglacials the loss of permanent subpolar sea ice cover and the emergence of low frequency variability in pacific ssts and global deep ocean circulation since 900 ka ice sheets have been the only component of the climate system to exhibit consistent low frequency variability with the exception of a near universal organization of low frequency power associated with marine isotope stages 11 and 12 all other components show an inconsistent distribution of power in frequency time space suggesting a highly nonlinear system response to orbital and ice sheet forcing most hypotheses for the origin of the mpt invoke a response to a long term cooling possibly induced by decreasing atmospheric pco2 none of these hypotheses however accounts for the geological constraint that the earliest northern hemisphere ice sheets covered a similar or larger area than those that followed the mpt given that the mpt was associated with an increase in ice volume this constraint requires that post mpt ice sheets were substantially thicker than pre mpt ice sheets indicating a change in subglacial conditions that influence ice dynamics we review evidence in support of the hypothesis that such an increase in ice thickness occurred as crystalline precambrian shield bedrock became exposed by glacial erosion of a thick mantle of regolith this exposure of a high friction substrate caused thicker ice sheets with an attendant change in their response to the orbital forcing marine carbon isotope data indicate a rapid transfer of organic carbon to inorganic carbon in the ocean system during the mpt if this carbon came from terrigenous sources an increase in atmospheric pco2 would be likely which is inconsistent with evidence for widespread cooling apparently rapid carbon transfer from terrestrial sources is difficult to reconcile with gradual erosion of regolith a more likely source of organic carbon and nutrients which would mitigate pco2 rise is from shelf and upper slope marine sediments which were fully exposed for the first time in millions of years in response to thickening ice sheets and falling sealevels during the mpt modeling indicates that regolith erosion and resulting exposure of crystalline bedrock would cause an increase in long term silicate weathering rates in good agreement with marine sr and os isotopic records we use a carbon cycle model to show that a post mpt increase in silicate weathering rates would lower atmospheric pco2 by 7 12 ppm suggesting that the attendant cooling may have been an important feedback in causing the mpt

line of sight displacement from alos 2 interferometry mw 7 8 gorkha earthquake and mw 7 3 aftershock interferometric synthetic aperture radar insar is a key tool for the analysis of displacement and stress changes caused by large crustal earthquakes particularly in remote areas a challenge for traditional insar has been its limited spatial and temporal coverage especially for very large events whose dimensions exceed the typical swath width of 70 100 km this problem is addressed by the alos 2 satellite whose palsar 2 instrument operates in scansar mode enabling a repeat time of 2 weeks and a swath width of 350 km here we present insar line of sight displacement data from alos 2 palsar 2 observations covering the mw 7 8 gorkha nepal earthquake and its mw 7 3 aftershock that were acquired within 1 week of each event the data are made freely available and we encourage their use in models of the fault slip and associated stress changes the mw 7 3 aftershock not only extended the rupture area of the main shock toward the east but also left a 20 km gap where the fault has little or no coseismic slip we estimate this unslipped fault patch has the potential to generate a mw 6 9 event

mediterranean climate and oceanography and the periodic development of anoxic events sapropels mediterranean sapropels are layers with elevated organic carbon concentrations that contrast with surrounding sediments which are organic poor sapropels occur quasi periodically in sedimentary sequences of the last 13 5 million years and exist both in the eastern and western mediterranean sub basins they have been the subject of extensive study based on records from both short conventional and long ocean drilling program sediment cores and from a wide variety of uplifted marine sediment sequences on the basin margins and islands previous syntheses in the 1990s and 2000s have discussed how the formation of sapropels is commonly ascribed to deep sea anoxia enhanced export productivity or a combination of these effects however a wealth of new evidence and insights has emerged during the past 1 2 decades based on traditional and novel proxy data as well as modelling which has revealed intriguing new aspects and nuances to the reconstructed conditions hence it is timely to present a new synthesis of current understanding of the processes behind the formation of sapropels which have over the past decade also become a matter of commercial interest in sub salt hydrocarbon exploration in this review we present a context of modern mediterranean climate and oceanography followed by an integrated assessment of the growing understanding of climatological and ocean circulation changes that were associated with sapropel deposition we find that sapropels predominantly formed during astronomically timed episodes when climatic and oceanographic conditions and ecological responses broadly preconditioned the basin for sapropel deposition there is strong correspondence with times of monsoon intensification fuelling runoff from north africa into the mediterranean sea while preconditioning due to sea level rise and regional precipitation and runoff may have contributed as well within these broad episodes of surface buoyancy gain and resultant decline in deep water ventilation specific deposition under dysoxic anoxic or even euxinic conditions occurred within a clearly dynamic system that was characterised by complex spatial and depth dependent patterns gradients with distinct temporal variability on at least decadal to centennial millennial timescales in the final section we evaluate the implications of different modes of deep water removal from silled basins to investigate why sapropels are more frequently and often more intensely developed in the eastern mediterranean than in the western mediterranean

interferometric processing of sentinel 1 tops data sentinel 1 s 1 has an unparalleled mapping capacity in interferometric wide swath iw mode three subswaths imaged in the novel terrain observation by progressive scans tops sar mode result in a total swath width of 250 km s 1 has become the european workhorse for large area mapping and interferometric monitoring at medium resolution the interferometric processing of tops data however requires special consideration of the signal properties resulting from the scansar type burst imaging and the antenna beam steering in azimuth the high doppler rate in azimuth sets very stringent coregistration requirements making the use of enhanced spectral diversity esd necessary to obtain the required fine azimuth coregistration accuracy other unique aspects of processing iw data such as azimuth spectral filtering image resampling and data deramping and reramping are reviewed giving a recipe like description that enables the user community to use s 1 iw mode repeat pass sar data interferometric results from s 1a are provided demonstrating the mapping capacity of the s 1 system and its interferometric suitability for geophysical applications an interferometric evaluation of a coherent interferometric pair over salar de uyuni bolivia is provided where several aspects related to coregistration deramping and synchronization are analyzed additionally a spatiotemporal evaluation of the along track shifts which are directly related to the orbital instrument timing error measured from the sar data is shown which justifies the necessity to refine the azimuth shifts with esd the spatial evaluation indicates high stability of the azimuth shifts for several slices of a datatake

geodetic model of the 2015 april 25 mw 7 8 gorkha nepal earthquake and mw 7 3 aftershock estimated from insar and gps data

on the timing and forcing mechanisms of late pleistocene glacial terminations insights from a new high resolution benthic stable oxygen isotope record of the eastern mediterranean abstract benthic oxygen isotope records of deep marine sedimentary archives have yielded a wealth of information regarding ice sheet dynamics and climate change during the pleistocene however since they often lack independent age control these records are generally bound by a fixed phase relationship between orbital forcing and the climate response e g ice volume changes we present the first long 1 2 ma benthic oxygen isotope record from the eastern mediterranean based on odp sites 967 and 968 which clearly reflects the behavior of global climate on a glacial interglacial scale throughout the late pleistocene time period the age model for our record is based on tuning the elemental ratio of titanium versus aluminum ti al against insolation the ti al record is dominated by the precession related changes in northern african climate i e monsoonal forcing and hence largely independent of glacial interglacial variability we found the largest offset between our chronology and that of the widely applied open ocean stacked record lr04 lisiecki and raymo 2005 for t vii 624 ka which occurred 9 kyr earlier according to our estimates though in agreement with the aicc2012 d ice chronology of epica dome c bazin et al 2013 spectral cross correlation analysis between our benthic 18 o record and 65 n summer insolation reveals significant amounts of power in the obliquity and precession range with an average lag of 5 5 0 8 kyr for obliquity and 6 0 1 0 kyr for precession in addition our results show that the obliquity related time lag was smaller 3 0 3 3 kyr prior to 900 ka than after 5 7 1 1 kyr suggesting that on average the glacial response time to obliquity forcing increased during the mid pleistocene transition much later than assumed by lisiecki and raymo 2005 finally we found that almost all glacial terminations have a consistent phase relationship of 45 45 with respect to the precession and obliquity driven increases in 65 n summer insolation consistent with the general consensus that both obliquity and precession are important for deglaciation during the late pleistocene exceptions are glacial terminations t iiib t 36 and potentially t 32 and t vii t 24 and t 34 which show this consistent phase relationship only with precession only with obliquity our findings point towards an early 1200 ka onset of the mid pleistocene transition vice versa the timing of t vii which can only be explained as a response to obliquity forcing indicates that the transition lasted until at least after mis 15

ionospheric correction of insar time series analysis of c band sentinel 1 tops data the copernicus sentinel 1a b satellites operating at c band in terrain observation by progressive scans tops mode bring unprecedented opportunities for measuring large scale tectonic motions using interferometric synthetic aperture radar insar although the ionospheric effects are only about one sixteenth of those at l band the measurement accuracy might still be degraded by long wavelength signals due to the ionosphere we implement the range split spectrum method for correcting ionospheric effects in insar with c band sentinel 1 tops data we perform insar time series analysis and evaluate these ionospheric effects using data acquired on both ascending dusk side of the sentinel 1 dawn dusk orbit and descending dawn side tracks over representative midlatitude and low latitude geomagnetic latitude areas we find that the ionospheric effects are very strong for data acquired at low latitudes on ascending tracks for other cases ionospheric effects are not strong or even negligible the application of the range split spectrum method despite some implementation challenges largely removes ionospheric effects and thus improves the insar time series analysis results

mediterranean quaternary sapropels an immediate response of the african monsoon to variation of insolation abstract in the subsurface of the east mediterranean sea eleven discrete basin wide organic rich black sapropels were deposited during the last 465 000 years they are dated by oxygen isotopic chronostratigraphy the most recent sapropel has been shown to be the consequence of heavy nile river summer floods due to increased monsoonal summer precipitation over ethiopia and not of scandinavian ice sheet meltwater influx into the east mediterranean sea as was previously believed while most sapropels were deposited during interglacials two thick sapropels formed during glacial periods as shown by their position in the oxygen isotopic stratigraphy and by their pollen record in core rc9 181 the new evidence presented here is that the sapropel sequence in this core including the two glacial sapropels correlates on a one to one basis with the highest values of an index of insolation on top of the atmosphere the concept of this index derives from an analysis of the african monsoon process the index variation is computed for the last 465 000 years from the caloric northern summer insolation in the tropical latitudes controlled by variations of the earth s orbital parameters it is conjectured that this index might be linked through the climate system to the monsoonal precipitation which in africa produces the nile river summer flood

obscuring of long eccentricity cyclicity in pleistocene oceanic carbon isotope records abstract long eccentricity 400 kyr cycles in carbon isotope records from the pacific and atlantic oceans and the mediterranean sea of the past 5 0 ma are compared all records show maximum 13c values 13cmax at eccentricity minima during the pliocene but this relationship obscured in the pleistocene after 1 6 ma in particular for the open ocean deep water 13c records since a clear anti phase relationship was set up between oceanic 18o and 13c in the 100 kyr band from this time we attribute the obscured 400 kyr signal to a major change in the oceanic carbon reservoir probably associated with restructure of the southern ocean a similar change occurred in the miocene at 13 9 ma when the 400 kyr cyclicity in 13c records flattened out together with a drastic cooling and antarctic ice sheet expansion a remarkable exception is the mediterranean surface water 13c record which remained paced by the long term eccentricity cycle throughout the pliocene and pleistocene suggesting a low latitude climatic origin of the 400 kyr signal that is independent of glacial interglacial forcing since the earth is currently passing through an eccentricity minimum it is crucial to understand the nature of the 13cmax events

timing of late pliocene to middle pleistocene tectonic events in rhodes greece inferred from magneto biostratigraphy and 40ar 39ar dating of a volcaniclastic layer we discovered a volcaniclastic layer in the plio pleistocene coastal sequences on the island of rhodes aegean fore arc greece here we present an integrated isotopic magnetostratigraphic and biostratigraphic planktonic foraminifers study for the haraki section where this layer is found intercalated in several meters of sedimentary rocks corresponding to the lindos bay clay member of the rhodes formation 40ar 39ar dating of the volcaniclastic layer provides an age of 1 89 0 09 ma which is consistent with our planktonic foraminiferal data magnetostratigraphic results show that the entire haraki section is of normal polarity and according to the isotopic results this corresponds to the olduvai subchron 1 95 1 77 ma the new age determination provides severe constraints for deciphering the sedimentary and tectonic evolution of rhodes since the late pliocene which can be summarized in the following 1 500 to 600 m drowning during the latest pliocene that could be related to the westward motion of the anatolian plate 2 at least 520 m of uplift at around 1 4 1 3 ma related to activity of the sinistral strike slip of the pliny trench the deep rhodes basin being separated from the island of rhodes 3 a counterclockwise rotation of rhodes younger than 1 2 1 1 ma and possibly synchronous with the young clockwise rotation of the western aegean arc

record of a tectonically controlled regression captured by changes in carbonate skeletal associations on a structured island shelf mid pleistocene rhodes greece the plio pleistocene warm temperate carbonate deposits along the se coast of rhodes greece formed on a highly structured island shelf during a major transgression regression cycle which reached bathyal depth during maximal transgression the complex palaeobathymetry exhibits many characteristics of submarine canyons especially of so called blind or headless canyons a canyon type which is especially common in the modern mediterranean this study presents the palaeoenvironmental evolution of one of these canyons which is today represented by the lardos valley eastern central rhodes the studied section comprises the middle pleistocene 900 300 ka and describes a shallowing upward trend from bathyal to circalitoral depth thin fossiliferous debris flow layers document turnovers and abundance changes in fauna and floral of hard bottom communities which developed on the adjacent basement slopes and highs the comparison of the obtained results with other studies from the southeastern coast of rhodes suggests a high degree of diachroneity of lithological boundaries of these plio pleistocene deposits which can be best explained by progressive infill of small depocentres located at different altitude levels hence lithological changes are interpreted to be time transgressive from distal low altitude to proximal high altitude during transgression while time transgressive from proximal to distal during regression consequently the best chronostratigraphic correlation horizon is the surface of maximal transgression the most probable age for this surface could be estimated at 1 1 to 0 8 ma 0 2 0 5 ma younger than previous estimates furthermore the current lithostratigraphic schemes for the plio pleistocene deposits of southeastern rhodes are reviewed and revised highlights the studied outcrop documents the uplift of rhodes during the middle pleistocene the plio pleistocene stratigraphy of rhodes is reviewed and revised the studied sedimentary unit is interpreted as submarine canyon deposit diachroneity of canyon deposits is most likely due to different altitudes of small depocentres

an onshore bathyal record of tectonics and climate cycles at the onset of the early middle pleistocene transition in the eastern mediterranean early pleistocene calabrian clays of the lindos bay formation have been uplifted and are exposed today on the eastern coast of rhodes hellenic forearc greece the hemipelagic origin of these sediments and the excellent preservation of the microfossils they contain make the lindos bay formation a unique element in the eastern mediterranean which has the potential to constitute a paleoclimate referential framework of the region for the early middle pleistocene transition empt in this context 98 samples were collected in the type locality section of the lindos bay formation stable isotope 18o 13c analyses were carried out on benthic uvigerina peregrina and planktonic globigerina bulloides foraminifera for the interval between 1100 ka and 858 ka we identify and continuously reconstruct the climate cycles that occurred between marine isotope stages mis 32 and 21 counts of planktonic foraminifera were further carried out and allow connecting the conditions occurring locally in the surface waters with the glacial interglacial cycles during the onset of the empt while sub tropical taxa dominate the assemblages glacials were associated with short term 10 kyr influxes of temperate to subpolar species suggesting cooling and or increasing productivity in the surface waters correlating with the deposition of sapropels in the eastern mediterranean deep sea finally planktonic benthic foraminiferal ratios show that the section deposited at upper bathyal depths between 450 m and 150 m during the late early pleistocene the eastern coast of rhodes has locally undergone repeated transient and possibly very rapid vertical motions which are overprinted on a regional tectonically forced regressive trend

early middle pleistocene transitions linking terrestrial and marine realms abstract marked by a progressive increase in the amplitude of climate oscillations an evolving waveform and a shift towards a quasi 100 ky frequency the early middle pleistocene transition empt previously known as the mid pleistocene transition or mid pleistocene revolution 1 4 0 4 ma represents a fundamental transformation in the earth s climate state the empt began with a substantial change in climate dynamics and ended with the mid brunhes event signaling the establishment of a new steady state the reasons for the empt while uncertain appear to involve a non linear response of the earth climate system the physical and biotic responses to this transition amplified by the growth of northern hemisphere ice sheets have been profound two important chronostratigraphic markers characterize the empt the jaramillo subchron 1 070 0 988 ma and the matuyama brunhes chron boundary 773 ka the latter has been chosen as the primary guide for the lower middle pleistocene subseries boundary as it lies at the approximate midpoint of the empt and aids in global recognition both in marine and terrestrial deposits the jaramillo subchron has received less attention but the late early pleistocene is important in europe because it saw the progressive transition from the villafranchian to galerian mammal faunas and expansion of hominins into western and northern europe the jaramillo subchron is represented by marine isotope stages mis 31 to 28 with mis 30 already showing the asymmetrical sawtooth pattern characteristic of the middle pleistocene indeed while variation in the 40 ky band obliquity remains strong throughout the empt low frequency variability begins at around 1250 1200 ky which coincides with a progressive increase in global ice volume against a backdrop of increasingly severe glacial cycles notably during mis 36 34 24 22 the so called 0 9 ma event 16 and 12 pronounced phases of warming are also documented globally including the super interglacial mis 31 the early phase of the empt is characterized by important glaciations beginning with mis 36 and continuing to mis 24 22 a major intensification of the east asian monsoon system intensification of loess deposition in northern europe development of open landscapes in western siberia increased fluvial incision higher amplitude sea level change and spread of large mammals across northern eurasia and a strong reduction in the north atlantic thermohaline circulation in europe the loss of thermophilous plant taxa during the empt and indeed throughout the quaternary is a reminder of the progressive cooling that took place here and elsewhere

planktonic benthonic foraminiferal ratios modern patterns and tertiary applicability abstract the abundance of planktonic specimens in foraminiferal assemblages was determined in numerous bottom samples from inner neritic to deep oceanic depths along the atlantic margin of the northeastern united states the results augment previous studies in other areas that have shown a general increase in percentage of planktonic specimens in total foraminiferal bottom assemblages as water depth increases the patterns found in this area of complex shelf bathymetry and hydrography illustrate the influence on the planktonic benthonic percentages of water depth distance from shore different water mass properties and downslope movement of tests in high energy areas the patterns found in the 661 samples from the atlantic margin were compared with results from 795 stations in the gulf of mexico pacific ocean and red sea the relative abundance of planktonic specimens and water depth correlates positively in all open oceanic areas even though taxonomic composition and diversity of the faunas from different areas is variable the variation of planktonic percentages in bottom samples within most depth intervals is large so that a precise depth determination cannot be made for any given value however an approximate upper depth limit for given percentages can be estimated for open ocean environments a decrease in planktonic percentages is seen in the lower salinity and higher turbidity coastal waters of the gulf of maine planktonic percentages intermediate between the lower values in the less saline coastal waters and the higher values in the normal open oceanic conditions occur in the transitional area between the gulf of maine and the open marine atlantic ocean to the east similarly lowered values in another area of restricted oceanic circulation occur in the high salinity clear but nutrient poor waters of the gulf of aqaba off the red sea a comparison of the similarity of modern planktonic percentage values to those found in earlier tertiary assemblages was made to confirm the usefulness of this measure in the fossil record in some stratigraphic sections in upper paleocene and lower eocene strata of the eastern gulf coastal plain water depths inferred from trends and values of planktonic percentages consistently match paleobathymetry constructed from physical stratigraphic characteristics and paleogeographic relationships

sentinel 1 insar measurements of deformation over discontinuous permafrost terrain northern quebec canada abstract differential synthetic aperture radar interferometry d insar has been applied in permafrost environments to detect surface deformation caused by freeze thaw processes in the active layer and underlying permafrost the effectiveness of sentinel 1 insar in monitoring ground surface deformation over continuous permafrost terrain above the treeline has been proven the heterogeneous landscape and developed vegetation cover increase the difficulty of applying d insar in sub arctic discontinuous permafrost terrain the potential of sentinel 1 insar in such an environment has not been fully explored in this study we explore the capabilities and limitations of applying sentinel 1 time series data for monitoring surface deformation over discontinuous permafrost terrain the interferometric coherence time series from september 2016 to april 2018 were analyzed over typical landscapes in discontinuous permafrost environments and their thaw subsidence curves are revealed by the small baseline subset sbas insar technique the seasonal thaw subsidence in the summer of 2017 was in the range of 15 80 mm in the study area the land cover types with thaw subsidence magnitudes from low to high are exposed land peatland lichen low shrub lichen dominated and wetland low vegetation the difference in displacement pattern between lichen dominated and wetland low vegetation dominated permafrost terrains is especially clear at the end of the thawing stage in september and october the differences in thaw subsidence magnitude and pattern reveal the influence of the soil water content in the active layer and permafrost properties on the thaw subsidence patterns we also compared the sentinel 1 retrieved cumulative displacement with the x band terrasar x and l band alos palsar results the difference of retrieved deformation magnitude using the three sensors is amplified when shrubs are more developed the findings indicate that sentinel 1 time series with a 6 day or 12 day span work well over discontinuous permafrost terrain above the tree line i e tundra tundra wetlands and less developed shrub tundra environments during the thawed season but the results and accuracy are not promising over developed shrub tundra and especially forest tundra environments

after the deluge mediterranean stagnation and sapropel formation in an east mediterranean marine core the upper sapropel begins soon after the start of a global event a very heavy precipitation which occurred in the equatorial latitudes during the late glacial early holocene this heavy precipitation in africa channelled by the nile river across 35 of latitude produced a low salinity surface layer in the east mediterranean in this confined basin with high bottom salinity the steep salinity gradient stratified the water column the stagnant bottom waters triggered the sapropel formation cretaceous sapropels in the tropical oceans may result from the same chain of events in warm humid climates with contrasting wet and dry seasonal rhythm

evolution of ocean temperature and ice volume through the mid pleistocene climate transition earth s climate underwent a fundamental change between 1250 and 700 thousand years ago the mid pleistocene transition mpt when the dominant periodicity of climate cycles changed from 41 thousand to 100 thousand years in the absence of substantial change in orbital forcing over this time an increase occurred in the amplitude of change of deep ocean foraminiferal oxygen isotopic ratios traditionally interpreted as defining the main rhythm of ice ages although containing large effects of changes in deep ocean temperature we have separated the effects of decreasing temperature and increasing global ice volume on oxygen isotope ratios our results suggest that the mpt was initiated by an abrupt increase in antarctic ice volume 900 thousand years ago we see no evidence of a pattern of gradual cooling but near freezing temperatures occur at every glacial maximum

review and new aspects concerning the formation of eastern mediterranean sapropels abstract in this paper it is proposed that the formation of eastern mediterranean sapropels occurred in an anti estuarine type of circulation which was to some degree weakened relative to the present in response to reduction of the eastern mediterranean excess of evaporation over freshwater input this reduction of excess evaporation would have been imposed by intensifications of 1 the indian ocean summer sw monsoon influencing the eastern mediterranean via increased nile discharge and 2 the system of mediterranean depressions an element of the westerly atlantic system causing increased precipitation and decreased evaporation both the indian ocean summer monsoon and the westerly atlantic system would be intensified in response to the occurrence of distinct minima in the cycle of precession it is demonstrated that reduced excess evaporation whether or not coinciding with global phases of deglaciation would lead to reduction of surface water salinities in the eastern mediterranean causing isolation of previously formed high salinity cooler deep water thus mixing was severely reduced possibly even restricted to eddy diffusion with only occasional convective events that because of the existing density gradient hardly ever would reach the deepest parts of the basin the consequently diminished oxygen advection down from a few hundred meters in the water column favoured preservation of the sinking organic matter this would however suffice only to enable the formation of sapropels with low organic carbon contents the high organic carbon contents observed in various sapropels are argued to reflect superimposed increases of export production the described scenario accounts for previously reported 1 increases of organic carbon content with increasing depth of deposition within individual sapropels and 2 asymmetrical sequences of sapropel deposition characterized by gradual build up and rather abrupt ending it is furthermore in agreement with 3 isotopic and faunal reconstructions of the history of exchange transports through both the strait of sicily and the strait of gibraltar and 4 faunal and floral reflections of the presence or absence of a distinct deep chlorophyll maximum with its associated increases in export production indicating the presence or absence of a shallow pycnocline within the euphotic layer moreover the described scenario 5 is in no way conflicting with the reports of sapropels in the western mediterranean and 6 seems to be endorsed by occasionally intercalated intervals suggestive of somewhat improved oxygenation amidst anoxic benthic desert levels a situation that has been observed in a few quaternary and pliocene sapropels

earthquake mechanisms and active tectonics of the hellenic subduction zone summary we use improved focal mechanisms and centroid depth estimates of earthquakes combined with gps velocities to examine the tectonics of the hellenic subduction zone and in particular the processes occurring at both ends of the hellenic arc nubia aegean convergence is accommodated by shallowly dipping thrust faulting along the subduction zone interface as well as by steeper splay faults in the overriding material from a comparison of observed and expected seismic moment release over the last 100 yr combined with existing knowledge of the longer term documented historical record we confirm earlier suggestions that most 80 per cent of this convergence is accommodated aseismically that is that the subduction zone is uncoupled this conclusion is robust even allowing for rare very large earthquakes on splay faults such as that of ad 365 and also allowing for the contribution of small earthquakes the downgoing nubian plate deforms by arc parallel contraction at all depths from 200 km seaward of crete to at least 100 km within the subducting slab extensional t axes of earthquakes are aligned downdip within the descending slab suggesting that even if the aseismic prolongation of the slab has reached the 670 km mantle discontinuity it does not transmit stresses to shallower depths shallow thrust faulting earthquakes on the subduction interface show a divergence of slip vectors round the arc and gps measurements show that this is accommodated mainly by e w extension on normal faults in the overriding aegean material the eastern end of the subduction zone south of rhodes displays distributed deformation in the overriding material including a mixture of strike slip and splay thrust faulting and probably involves rotations about a vertical axes here slip on the interface itself is by thrust faulting with slip vectors oblique to the arc but parallel to the overall nubia aegean convergence there is no evidence for slip partitioning in the traditional sense in the west the subduction zone terminates in a distributed zone of parallel ne sw strike slip faults of which the most prominent is the kefalonia transform fault ktf a flexural gravity anomaly confirms that the deep bathymetric escarpment of the ktf is a lateral ramp formed as the ionian islands are emplaced sw onto the apulian lithosphere and enhanced by minor thrust faulting with slip vectors perpendicular to the scarp distributed parallel strike slip faults both sw and ne of mainland central greece terminate in e w graben in central greece which accommodate the overall ne sw shear by clockwise block rotation central greece therefore acts as a relay zone between the strike slip faulting of the ne aegean and the ionian islands western peloponnese

plio pleistocene cliff bound wedge shaped warm temperate carbonate deposits from rhodes greece sedimentology and facies abstract the pliocene to pleistocene temperate carbonates of rhodes were deposited in a tectonically active region strongly influenced by a complicated and rapidly changing topography provided by the highly tectonised late cretaceous lindos limestone as basement rock deposition on this basement took place in accommodation loci restricted to micrograbens and their downslope extension to the foot of steep submarine cliffs to basement neptunian dykes and depressions in the basement rock consequently the sediments comprise a high degree of facies variability and are typically thin and laterally discontinuous the integration of several outcrops is necessary for the reconstruction of the stratigraphy and the relative sea level changes the sediments were deposited during a large scale tectonically driven transgressive regressive cycle in water depths changing from zero to several hundreds of metres at the studied lindos pefkos road cutting the kolymbia limestone bound to the foot of lindos limestone cliffs marks the onset of the marine deposition in the late pliocene its fabric is a rudstone consisting of unsorted angular lindos limestone clasts up to boulder size with a matrix dominated by molluscs and coralline algae the overlying plio pleistocene st paul s bay limestone consists of deep water float and rudstones containing the white coral community dominated by the coral lophelia pertusa its matrix shows a complex fabric of up to five sediment zones separated by differing states of lithification in this maximum flooding phase mineralised hardgrounds indicate depositional hiati the subsequent shallowing phase is represented by the cape arkhangelos calcarenite a series of distinctive facies of very patchy distribution they are characterised by the bryozoan brachiopod facies overlain by a facies heavily dominated by the bivalve mytilaster sp mytilaster facies conspicuous for the mytilaster facies is the inverse concave up stacking pattern of shelly material this facies is followed by a serpulid framestone and associated serpulid rudstone neptunian dykes cut through the first two facies and are filled with an intraformational breccia grading into a breccia with abundant mytilaster facies clasts neptunian dyke facies the sedimentology and interpretation of each facies include a description of the ichnology in particular the bioerosion peculiar to each facies the separation of different gravity transport processes in steep submarine environments is rarely described and most of the literature concentrates on siliciclastic dominated coarse grained sandy or gravely sand delta environments for a classification of the transport processes of the examined deposits the following criteria were evaluated sediment body symmetry inclination of the palaeorelief sediment constituents fabric complexity sedimentary structures and availability of fine matrix sedimentary structures and grading can be camouflaged in carbonates due to density differences of bioclasts however bioclast orientations such as bivalve stacking patterns can give information about the sedimentary process we suggest the inverse concave up stacking pattern of bivalve shells to be a texture potentially indicative for debris falls because of the above mentioned criteria we classified the kolymbia limestone as rock fall deposits and the st paul s bay limestone as well as the mytilaster facies of the cape arkhangelos calcarenite as debris fall deposits the bryozoan brachiopod facies could not be classified with certainty because of the lack of sedimentary structures and bioclast orientation however a grain flow or most likely a debris fall transport process seems probable

plio pleistocene high low latitude climate interplay a mediterranean point of view abstract the high low latitude climate interplay during the plio pleistocene global cooling is not yet well understood insight on the mediterranean region can provide some clues about past significant climate changes since the basin reflects the climate dynamics of both high latitude and low latitude regions being connected to the north atlantic and subjected to monsoon influence here we shade light on this connection problem by performing a spectral analysis on an eastern mediterranean stack of planktonic records spanning the last 5 ma and by further comparing it to north atlantic and pacific deep and surface water records our main conclusion is that the mediterranean detected the main global climate transitions over the last 5 myr although sapropel depositions indicate that it remained influenced by the african summer monsoon during the whole interval our analysis reveals that until 2 2 ma the mediterranean planktonic record is driven by regional processes dominated by precession the progressive emergence of the 41 kyr frequency in the mediterranean records around 2 8 ma suggests that since this date the mediterranean was more and more affected by the high latitude climate dynamics forcing than by the low latitude one moreover during the ongoing plio pleistocene cooling the 41 kyr frequency signal in the mediterranean records anticipated high latitude deep water response to the intensification of the northern hemisphere glaciations nhg and lagged the signal in tropical latitudes finally toward 1 2 ma the results suggest that the progressive shift from the 41 kyr to the 100 kyr frequency was led by the northern high latitudes overall our results confirm that the mediterranean is an ideal site to study the interplay between high and low latitude climates

slip model of the 2015 mw 7 8 gorkha nepal earthquake from inversions of alos 2 and gps data we use surface deformation measurements including interferometric synthetic aperture radar data acquired by the alos 2 mission of the japanese aerospace exploration agency and global positioning system gps data to invert for the fault geometry and coseismic slip distribution of the 2015 mw 7 8 gorkha earthquake in nepal assuming that the ruptured fault connects to the surface trace of the main frontal thrust mft fault between 84 34 e and 86 19 e the best fitting model suggests a dip angle of 7 the moment calculated from the slip model is 6 08 1020 nm corresponding to the moment magnitude of 7 79 the rupture of the 2015 gorkha earthquake was dominated by thrust motion that was primarily concentrated in a 150 km long zone 50 to 100 km northward from the surface trace of the main frontal thrust mft with maximum slip of 5 8 m at a depth of 8 km data thus indicate that the 2015 gorkha earthquake ruptured a deep part of the seismogenic zone in contrast to the 1934 bihar nepal earthquake which had ruptured a shallow part of the adjacent fault segment to the east

toward operational compensation of ionospheric effects in sar interferograms the split spectrum method the differential ionospheric path delay is a major error source in l band interferograms it is superimposed to topography and ground deformation signals hindering the measurement of geophysical processes in this paper we proceed toward the realization of an operational processor to compensate the ionospheric effects in interferograms the processor should be robust and accurate to meet the scientific requirements for the measurement of geophysical processes and it should be applicable on a global scale an implementation of the split spectrum method which will be one element of the processor is presented in detail and its performance is analyzed the method is based on the dispersive nature of the ionosphere and separates the ionospheric component of the interferometric phase from the nondispersive component related to topography ground motion and tropospheric path delay we tested the method using various advanced land observing satellite phased array type l band synthetic aperture radar interferometric pairs with different characteristics high to low coherence moving and nonmoving terrains with and without topography and different ionosphere states ionospheric errors of almost 1 m have been corrected to a centimeter or a millimeter level the results show how the method is able to systematically compensate the ionospheric phase in interferograms with the expected accuracy and can therefore be a valid element of the operational processor

neogene sapropels in the mediterranean a review for 50 years the existence of sapropels organic carbon rich sediments deposited within plio pleistocene sediments of the mediterranean sea has been known initially research concentrated on material recovered in relatively short gravity piston cores taken from the eastern basins where sequences were found to be well developed preserved and had extensive spatial coverage in the main previous studies concentrated upon establishing a workable stratigraphy spatial correlation of individual layers and determining the probable depositional mechanisms however despite a plethora of research papers some issues still remain unresolved this is in part due to a lack of agreement between investigators sampling and analytical short comings restricted sample size and the fact that in many instances like was not being compared with like recently the limit of sapropels in the western basin has been further extended as a result the palaeoceanographic palaeoclimate models which had previously been developed for deposition of sapropels in the eastern basin have been modified most recently strong links have been established between astronomical cyclicity and sapropel formation this review paper provides a summary of sapropel research to date and ongoing sapropel research in the mediterranean some of which appears in this thematic issue of marine geology it is fitting that this thematic issue of marine geology be dedicated to the memory of colette vergnaud grazzini and rob kidd who in many ways helped to initiate the resurgence in sapropel studies in the 1970s in the mediterranean perhaps in 50 more years we will know all of the answers 1999 elsevier science b v all rights reserved

toward full exploitation of coherent and incoherent information in sentinel 1 tops data for retrieving surface displacement application to the 2016 kumamoto japan earthquake sentinel 1 s continuous observation program over all major plate boundary regions makes it well suited for earthquake studies however decorrelation due to large displacement gradients and limited azimuth resolution of the terrain observation by progressive scan tops data challenge acquiring measurements in the near field of many earthquake ruptures and prevent measurements of displacements in the along track direction here we propose to fully exploit the coherent and incoherent information of tops data by using standard interferometric synthetic aperture radar insar split bandwidth interferometry in range and azimuth swath burst overlap interferometry and amplitude cross correlation to map displacements in both the line of sight and the along track directions application to the 2016 kumamoto earthquake sequence reveals the coseismic displacements from the far field to the near field by adding near field constraints the derived slip model reveals more shallow slip than obtained when only using far field data from insar highlighting the importance of exploiting all coherent and incoherent information in tops data

vegetation response to obliquity and precession forcing during the mid pleistocene transition in western mediterranean region odp site 976 abstract the odp leg 161 site 976 alboran sea is a deep sea section sampled at a water depth of 1108 m in the western mediterranean sea pollen analysis provides a vegetation and climate record of the mid pleistocene transition mpt roughly one million years ago the age model tied to biostratigraphic events was revised by aligning the pollen climate index pci to mediterranean kc01b and global lr04 oxygen isotope records the studied time slice spans the interval 1 09 ma mis 31 to 0 90 ma mis 23 across this interval past phytogeography of nowadays extinct taxa which were rare allows a successful application of the modern analogues technique mat to quantitative climate reconstructions for the mpt five long term obliquity related vegetation successions o1 to o5 and eight short term precession related vegetation successions p1 to p8 are observed within the studied interval these vegetation successions regardless of their duration show the same pattern the progressive replacement of temperate trees by mountainous taxa and then by herbs and steppe maxima precession related successions correspond therefore to as dramatic vegetation changes as those driven by obliquity including a final steppe phase under deteriorated climate conditions wavelet analysis of the pci record shows that the western mediterranean experienced a shift at 1 01 ma from precession dominated frequencies 1 05 1 01 ma to obliquity dominated frequencies 1 01 0 9 ma there is therefore an apparent discrepancy between wavelet analysis results and vegetation dynamic analysis which suggests that obliquity and precession are recorded throughout the entire studied interval this discrepancy could result from the fact that the pci record sums somehow similar vegetation changes wet to dry occurring at different periodicities such a complex vegetation dynamics is mathematically rendered through a single parameter i e principal component which does not successfully catch the subtle combinations of variability occurring at two close periodicities furthermore the pollen inferred early pleistocene vegetation dynamic and climate of the western mediterranean region does not show a decrease of the obliquity response relative to the precession response at the onset of the mpt

stable carbon and oxygen isotope compositions of invertebrate carbonate shells and the reconstruction of paleotemperatures and paleosalinities a case study of the early pleistocene of rhodes greece abstract the coastal sediments of rhodes in the eastern mediterranean have recorded transgression regression cycles that took place during the early pleistocene the sedimentary deposits from the kritika member of the rhodes formation consist in conglomerates sandstones siltstones and clays deposited in brackish to shallow marine environments faunal associations are dominated by molluscs and reveal rapid ecological changes carbon and oxygen isotope ratios of aquatic skeletal carbonates show that these ecological changes were most likely driven by large salinity changes while water temperature remained rather constant at about 22 0 1 5 c the tectonic activity of the island rather than glacio eustatic variations of climatic origin is advocated to be responsible for the ecological and salinity changes and sea level variations recorded in the sedimentary sequence

paleoenvironmental changes during sapropel 19 i cycle 90 deposition evidences from geochemical mineralogical and micropaleontological proxies in the mid pleistocene montalbano jonico land section southern italy an integrated micropaleontological geochemical and mineralogical study has been performed across the mid pleistocene sapropel 19 i cycle 90 from the montalbano jonico land section southern italy to reconstruct the paleoenvironmental conditions at time of its formation the sapropel interval is characterized by two oxygen depletion phases phase a and c interrupted by a temporary re oxygenation interval phase b the beginning and the end of sapropel deposition are dated at 957 0 81 kyr and 950 0 86 kyr respectively the duration of the interruption is estimated to 0 350 0 32 kyr the multiproxy approach highlights that deposition of sapropel 19 reflects a period of enhanced freshwater runoff induced by a wetter climate as a consequence of a more efficient fluvial erosion a higher terrigenous input mostly ascribable to a southern apennines source and an increased turbidity of surface waters accompanied most of sapropel deposition biotic and abiotic proxies document that different paleoenvironmental conditions occur through phases a c the beginning of phase a is characterized by warm on land paleoclimate as well as warm and oligotrophic surface water conditions during the upper part of phase a temperature starts decreasing and surface waters appear more productive this change probably represents the prelude to cooler and drier conditions characterizing phase b which displays a river supply reduction and an eolian input increase sahara dust during phase c the restored depleted oxygen environment at the bottom sediments is clearly coupled with the re establishment of humid conditions and increased river supply at the same time enhanced mixing of water column a cooler paleoclimate and increased productivity of surface waters are recorded the latter likely favored by the enhanced mixing of water column and also increased delivery of land derived nutrients the end of phase c is marked by a restored normal run off enhanced productivity in surface waters and low oxygen conditions at the bottom sediments persist slightly above phase c the overall results suggest that the onset of sapropel deposition is related to water stratification that caused low oxygen exchanges with the sea bottom although enhanced productivity characterizes most of the sapropel deposition it was not the primary factor triggering sapropel deposition

brucite and carbonate assemblages from altered olivine rich materials on ceres the mineralogy of the dwarf planet ceres has long remained uncertain the infrared spectral features of this planetary body are indicative of minerals derived from the aqueous alteration of olivine rich materials suggesting that ceres is not represented by any known meteorite the dwarf planet ceres is the largest object in the asteroid belt and is generally thought to be a differentiated body composed primarily of silicate materials and water ice1 2 some remotely observed features however indicate that ceres may instead have a composition more similar to that of the most common types of carbonaceous meteorite3 4 5 6 7 in particular ceres has been shown to have a distinct infrared absorption feature centred at a wavelength of 3 06 m that is superimposed on a broader absorption from 2 8 to 3 7 m refs 5 8 which suggests the presence of oh or h2o bearing phases the specific mineral composition of ceres and its relationship to known meteorite mineral assemblages however remains uncertain here we show that the spectral features of ceres can be attributed to the presence of the hydroxide brucite magnesium carbonates and serpentines a mineralogy consistent with the aqueous alteration of olivine rich materials we therefore suggest that the thermal and aqueous alteration history of ceres is different from that recorded by carbonaceous meteorites and that samples from ceres are not represented in existing meteorite collections

forearc uplift rates deduced from sediment cores of two coastal lakes in south central chile abstract the present paper introduces a new approach for deriving information about local forearc tectonics and related uplift rates based on the study of lake sediments we investigated two coastal lakes at the south central chile margin lakes lanalhue and lleu lleu located south of the arauco peninsula 38 s both lakes developed within the valleys of ancient rivers that once drained to the pacific ocean being subsequently dammed by rising sills in the late pleistocene early holocene seismic profiling and sedimentological analyses of cores from both lakes revealed similar successions consisting of marine to brackish sediments covered by lacustrine deposits radiocarbon dating indicates that the marine lacustrine transition occurred at 8 ka and 8 15 ka respectively the correlation of this transition with global sea level curves allowed the calculation of local uplift rates for the holocene uplift rates for the lake basins amount to 0 42 0 71 and 0 49 0 44 mm a respectively which are consistent with rates determined from a late pleistocene marine terrace in the area however conspicuously higher though likely transient vertical movements at 8 83 2 7 mm a and 11 36 1 77 mm a respectively were calculated for the sills that block both lakes nowadays these barriers are interpreted to be the surface expression of a blind reverse fault associated to the morguilla fault system a seismically active structure that controls uplift and folding along the adjacent arauco peninsula

sedimentary evolution of a late pleistocene temperate red algal reef coralligene on rhodes greece correlation with global sea level fluctuations autochthonous red algal structures known as coralligene de plateau occur in the modern warm temperate mediterranean sea at water depths from 20 to 120 m but fossil counterparts are not so well known this study describes from an uplifted coastal section at plimiri on the island of rhodes a 450 m long by 10 m thick late pleistocene red algal reef coralligene facies interpreted as being a coralligene de plateau and its associated deposits the coralligene facies constructed mainly by lithophyllum and titanoderma sits unconformably upon the plio pleistocene rhodes formation and is overlain by a maerl facies 2 m a mixed siliciclastic carbonate facies 0 2 m and an aeolian sand facies 2 5 m the three calcareous facies of heterozoan character are correlated with established members in the lindos acropolis formation in the north of the island while the aeolian facies is assigned to the new plimiri aeolianite formation the palaeoenvironmental and genetic stratigraphic interpretations of these mixed siliciclastic carbonate temperate water deposits involved consideration of certain characteristics associated with siliciclastic shelf and tropical carbonate shelf models such as vertical grain size trends and the stratigraphic position of zooxanthellate coral growths integration of these results with electron spin resonance dates of bivalve shells indicates that the coralligene facies was deposited during marine isotope stage 6 to 5e transgressive event ca 135 to 120 ka in water depths of 20 to 50 m and the overlying maerl facies was deposited during regression from marine isotope stage 5e to 5d ca 120 to 110 ka at water depths of 25 to 40 m the capping aeolian sand facies involving dual terrestrial subunits is interpreted as having formed during each of the glacial intervals marine isotope stages 4 71 to 59 ka and 2 24 to 12 ka with soil formation during the subsequent interglacial periods of marine isotope stages 3 and 1 respectively accumulation rates of about 0 7 mm year 1 are estimated for the coralligene facies and minimum accumulation rates of 0 2 mm year 1 are estimated for the maerl facies the existence of older red algal reefs in the plimiri region during at least marine isotope stages 7 245 to 186 ka and 9 339 to 303 ka is inferred from the occurrence of reworked coralligene type lithoclasts in the basal part of the section and from the electron spin resonance ages of transported bivalve shells

integrated stratigraphy and astronomical tuning of lower middle pleistocene montalbano jonico section southern italy abstract astronomical calibration of the lower middle pleistocene montalbano jonico section located in the lucania basin southern italy is presented previous papers widely discussed the integrated stratigraphy calcareous nannofossils sapropel stratigraphy benthic and planktonic oxygen stable isotopes and the paleoenvironmental features of this section and its potential suitability for the selection of the middle pleistocene global stratotype section and point gssp in this study new planktonic 18 o data additional biostratigraphical constraints and new tephrochronology on volcaniclastic layers occurring within the studied record are reported the new chronostratigraphic framework provides a robust base for correlation of the oxygen isotope stratigraphy for the montalbano jonico section with the glacial and interglacial fluctuations of the oceanic and mediterranean 18 o reference deep sea records specifically the lower part of the montalbano jonico section interval a provides correlation of the planktonic and benthic 18 o cycles to marine isotope stage mis 36 to mis 23 interval a includes a distinct peak of left coiled neogloboquadrinids the globoratalia crassaformis influx the first occurrence of gephyrocapsa omega and the first common occurrence and last common occurrence of reticulofenestra asanoi these stratigraphical constraints support the tuning of five sapropel layers included in this part of the section to insolation cycles i 112 i 104 i 102 i 90 and i 86 the upper part of the section interval b which includes the temporary disappearance td2 of g omega and tephra layer v5 ar ar age dated at 719 5 12 6 ka is consistent with identification of mis 22 to mis 16 in the planktonic 18 o pattern the 18 o time series of the whole section was reconstructed using the midpoints of individual sapropels and their correlative precession minima visual comparison of the 18 o pattern with the record available at the mediterranean odp site 975 and in the upper part of the section the ar ar age of tephra v5 the developed astronomical tuning revealed that the montalbano jonico section covers an interval from 1240 ka to 645 ka a significant change in sedimentation rate occurs between intervals a 0 53 m ky and interval b 0 91 m ky at about 870 ka and is consistent with a sea level drop from a bathyal to a circalittoral environment bioevents recognised in the montalbano jonico section have been dated according to the astronomical calibration and age assignments of tephra v1 v4 and v6 v9 are also proposed the montalbano jonico section fills the gap between the top of the vrica section and the base of the ionian informal middle pleistocene stage and represents a mediterranean reference section for the mid pleistocene transition

vegetation changes during the late early pleistocene at montalbano jonico province of matera southern italy based on pollen analysis pollen analysis of the early pleistocene montalbano jonico section in southern italy reveals cyclic changes driven by climate and eustasy as illustrated by mesothermic vs steppe elements for climate and pinus vs caryophyllaceae amaranthaceae chenopodiaceae and ephedra for eustasy these results are directly compared with oxygen isotope data on globigerina bulloides constrained within a biostratigraphic framework based on nannofossils and foraminifers facilitating a new age calibration for the section marine isotopic stages 37 to 23 1 250 0 900 ma are recorded and compared with global and mediterranean oxygen isotope curves high frequency changes in pollen are related to the mediterranean curve globigerinoides ruber from odp site 967 and superimposed the lr04 stack curve during the early pleistocene pollen recorded global and regional climate changes related to obliquity and precession respectively and regional tectonic evolution precession forcing was caused by mediterranean wetness related to precession the intensified precession effect over climatic cycles that is expected during the middle pleistocene transition is not recorded in the montalbano jonico interval a vegetation changes

sea level and deep sea temperature variability over the past 5 3 million years ice volume and hence sea level and deep sea temperature are key measures of global climate change sea level has been documented using several independent methods over the past 0 5 million years myr older periods however lack such independent validation all existing records are related to deep sea oxygen isotope 18o data that are influenced by processes unrelated to sea level for deep sea temperature only one continuous high resolution mg ca based record exists with related sea level estimates spanning the past 1 5 myr here we present a novel sea level reconstruction with associated estimates of deep sea temperature which independently validates the previous 0 1 5 myr reconstruction and extends it back to 5 3 myr ago we find that deep sea temperature and sea level generally decreased through time but distinctly out of synchrony which is remarkable given the importance of ice albedo feedbacks on the radiative forcing of climate in particular we observe a large temporal offset during the onset of plio pleistocene ice ages between a marked cooling step at 2 73 myr ago and the first major glaciation at 2 15 myr ago last we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep sea temperature a novel approach to the estimation of sea level and deep sea temperature has been used to determine these quantities over the past 5 3 million years this approach based on oxygen isotope records from the eastern mediterranean shows that temperature and sea level histories are broadly correlated but also show intriguing temporal offsets most records of past sea level variation and associated changes in ocean temperature rely on variations in oxygen isotopes recorded in deep sea marine microorganisms these signals unfortunately are confounded by other influences making it difficult to extract a clear climate related signal eelco rohling and colleagues now present a novel approach to estimating sea level and deep sea temperature variations for the past 5 3 million years the record based on oxygen isotope variations from the eastern mediterranean avoids the issues of the deep sea approach and generally corresponds to an independent record of the past 1 6 million years as expected temperature and sea level are broadly correlated but also show intriguing temporal discontinuities as at the initiation of plio pleistocene ice ages when a major sea level drop lagged a sharp temperature decline by several hundred thousand years

paleoproductivity the benthic planktonic ratio in foraminifera as a productivity index abstract when the effects of differential dissolution are excluded the benthic to planktonic ratio in deep sea foraminifera can be read as a productivity index for pelagic conditions we use the bz index which is the product of the benthic planktonic ratio in percent and the depth of deposition which controls supply of organic matter for hemipelagic conditions we use bz d which is the product of the bz value and a factor for proximity to the shore square root of distance from land which controls coastal productivity anomalous values readily stand out from the normal populations which cluster around typical values of bz or bz d off northwest africa wherever calcite dissolution can be excluded as a factor because of presence of aragonite these anomalies are due to lateral supply of redeposited organic matter

climate forcing of terrigenous sediment input to the central mediterranean sea since the early pleistocene clay mineralogy of odp site 964 in the ionian sea was investigated in order to reconstruct variations in detrital sediment input to the central mediterranean sea and to reconstruct the corresponding climatic processes over the last 1500 kyr the clay mineralogy of odp site 964 indicates a major shift in sedimentary sources from the saharan desert which is characterized by a clay mineral assemblage of palygorskite illite kaolinite to the apennine peninsula characterized by an illite smectite clay assemblage at 700 kyr prior to 700 kyr the low smectite content 10 20 and the strong precessional cycles in the variations of kaolinite illite and palygorskite indicate that terrigenous sediment to the central mediterranean sea mainly originated from saharan dust and was strongly affected by the african monsoon with a minor contribution of sediment deriving from the apennine peninsula an increase in the illite kaolinite ratio in the maxima of boreal summer insolation indicates a decreased dust input from the southern sahara as a result of the northward displacement of the african monsoon itcz system a gradual increase in smectite content has been identified between 1050 and 500 kyr probably associated with environmental vegetation and or hydrological changes in southern europe linked to the occurrence of the mpt and partly to tectonic uplift in the apennine peninsula a marked increase in terrigenous flux is observed at around 350 kyr coeval with a major phase of uplift in the calabrian arc

the depth dependency of planktonic benthic foraminiferal ratios constraints and applications abstract study of the ratio between planktonic and benthic foraminifera in a great number of areas shows that variation of this ratio with depth can be described using organic matter flux equations essentially the share of benthic foraminifera in the total association is inversely proportional to depth as is the amount of organic matter resulting from primary productivity reaching the sea bottom variation in the p b ratio from area to area appears to be strongly dependent on the amount of inbenthic living foraminifera if the ratios are corrected for this the regressions between the proportion of planktonic foraminifera p and depth appear to be near identical in the gulf of mexico the gulf of california the west coast of the usa and the adriatic sea this regression can be described by depth e 3 58718 0 03534 p a study of the behaviour of this function in nine cores from the adriatic upper quaternary reveals that the palaeodepth reconstructions are not influenced by fluctuations in productivity and temperature but that they are significantly influenced by redeposition of fine grained deposits

development of a prograding carbonate wedge during sea level fall lower pleistocene of rhodes greece a lower pleistocene carbonate platform is described from north east rhodes greece it comprises a succession of warm temperate calcarenites the cape arkhangelos calcarenite facies group developed in a steep sided coastal basin the depositional setting for the sediments is a carbonate wedge developed within a larger scale forced regression deposition began with aggradation of storm dominated lower and upper shoreface deposits later the development of a prograding platform produced giant clinoform foresets a marked alternation of cross bedded and bioturbated clinoforms indicates seasonal transport of carbonate material off the platform periodically the platform edge has been deeply scoured by exceptional storms after which further deposition repaired the platform margin and progradation resumed more than 20 such major storm cycles are preserved applying sequence stratigraphy to this succession leads to two different possible interpretations one with a lowstand systems tract and one with a forced regressive systems tract depending on the scale of view the implications of this are discussed the present example shows clearly that the application of sequence stratigraphic models to real carbonate sequences requires careful consideration of scale and context before interpretations are made

tectonic and anthropogenic deformation at the cerro prieto geothermal step over revealed by sentinel 1a insar the cerro prieto geothermal field cpgf lies at the step over between the imperial and the cerro prieto faults in northern baja california mexico while tectonically this is the most active section of the southern san andreas fault system the spatial and temporal deformation in the area is poorly resolved by the sparse global positioning system gps network coverage moreover interferograms from satellite observations spanning more than a few months are decorrelated due to the extensive agricultural activity in this region here we investigate the use of frequent short temporal baseline interferograms offered by the new sentinel 1a satellite to recover two components of deformation time series across these faults following previous studies we developed a purely geometric approach for image alignment that achieves better than 1 200 pixel alignment needed for accurate phase recovery we construct interferometric synthetic aperture radar time series using a coherence based small baseline subset method with atmospheric corrections by means of common point stacking we did not apply enhanced spectral diversity because the burst discontinuities are generally small 1 4 mm and can be effectively captured during the atmospheric corrections with these algorithms the subsidence at cpgf is clearly resolved the maximum subsidence rate of 160 mm yr due to extraction of geothermal fluids and heat dominates the 40 mm yr deformation across the proximal ends of the imperial the cerro prieto and the indiviso faults

the last 1 35 million years at tenaghi philippon revised chronostratigraphy and long term vegetation trends abstract in addition to being of interest to ancient greek and roman historians the site of philippi ne greece has long been noted in quaternary circles for providing the longest continuous european pollen record spanning the last one million years here the original age model is re evaluated and a new marine terrestrial correlation is proposed an astronomical calibration procedure based on a correspondence between changes in certain vegetation elements and march and june perihelion configurations suggests that the base of the sequence extends back to 1 35 million years ago the revised chronological framework for the tenaghi philippon sequence provides an opportunity to examine the long term behaviour of individual taxa and vegetation trends within the context of global climate changes comparisons reveal a close correspondence between the terrestrial and marine records in terms of orbital and suborbital variability however joint time frequency analysis of the arboreal pollen record shows that the obliquity and eccentricity precession signals persist into the 100 kyr and 41 kyr worlds respectively suggesting the operation of additional climate mechanisms that are independent of high latitude glacial interglacial effects unlike ice core and marine sequences no change in the magnitude of interglacial tree population expansions is observed after the mid brunhes event instead the tenaghi philippon record suggests a major shift in the vegetational composition of interglacials after mis 16 with the establishment of forests of reduced diversity and a modern appearance

rupture process of the mw 7 9 2015 gorkha earthquake nepal insights into himalayan megathrust segmentation we investigate the rupture process of the 25 april 2015 gorkha earthquake mw 7 9 using a kinematic joint inversion of teleseismic waves strong motion data high rate gps static gps and synthetic aperture radar sar data the rupture is found to be simple in terms of coseismic slip and even more in terms of rupture velocity as both inversion results and a complementing back projection analysis show that the main slip patch broke unilaterally at a steady velocity of 3 1 3 3 km s this feature likely contributes to the moderate peak ground acceleration 0 2 g observed in kathmandu the 15 km deep rupture occurs along the base of the coupled portion of the main himalayan thrust and does not break the area ranging from kathmandu to the front the limitation in length and width of the rupture cannot be identified in the preearthquake interseismic coupling distribution and is therefore discussed in light of the structural architecture of the megathrust

improved correction of seasonal tropospheric delay in insar observations for landslide deformation monitoring abstract synthetic aperture radar interferometry insar provides an effective tool to study slow moving landslides however insar observations are often contaminated by tropospheric artefacts due to spatial and temporal variations of atmospheric refractivity particularly the topography dependent stratified delays may introduce seasonal oscillation biases into insar measured deformation time series under steep terrains which cannot be removed by conventional spatial and temporal filtering in this study we proposed two complementary approaches to correct the stratified tropospheric delays for time series insar analysis when studying single landslides one is the iterative linear model ilm as an improved version of the traditional linear model lm the other is to fuse tropospheric delays predicted by several global weather models fdwm with different temporal intervals and spatial resolutions both methods are integrated into the standard small baseline subset sbas time series analysis procedure we evaluated the proposed methods in three landslide prone areas in southwest china using sentinel 1 datasets the experimental results demonstrated that the ilm method removed the seasonal stratified delays mixed in deformation time series unaffected by the deforming points the fdwm method achieved an optimal combination of tropospheric delay predictions by four weather models i e era interim era5 hres ecmwf and merra 2 validations using in situ gps measurements suggested that the original root mean squared rms values of interferometric phases declined by more than 35 after both ilm and fdwm corrections the ilm had better performances than the fdwm to correct stratified delay for single landslides whereas the fdwm can be an effective alternative when the ilm is inapplicable in case of limited coherent points

independent component analysis and parametric approach for source separation in insar time series at regional scale application to the 2017 2018 slow slip event in guerrero mexico