dinoflagellate cyst based modern analogue technique at test a 300 year record from the gulf of taranto eastern mediterranean abstract to test the performance of dinoflagellate cyst based palaeoenvironmental reconstructions derived via the modern analogue technique mat and a non quantitative method we have compared reconstructions of mixed layer temperature sea surface temperature and mixed layer salinity of a well dated site from the gulf of taranto to instrumental data of air temperature precipitation and river discharge two hypotheses are tested the reconstructions of dinoflagellate cyst based mat improve when a a local reference dataset rather than an extra regional reference dataset is used b the reference and downcore datasets are corrected for species specific preservation prior to analysis this is achieved by executing four experiments based on different reference datasets 1 a north atlantic dataset including all species 2 a north atlantic dataset including degradation resistant species 3 a mediterranean dataset including all species 4 a mediterranean dataset including degradation resistant species only we show that mat based reconstructions improve when a local rather than an extra regional reference dataset is used exclusively including species resistant to degradation improves the reconstruction if an extra regional reference dataset is used but leads to considerable loss of variability if the local reference dataset is used both mat based and qualitative reconstructions correlate to instrumental data for industrial times for pre industrial times mat reconstructions of variability in temperature and salinity do not co vary with variability in the instrumental data whereas qualitative reconstructions provide a relatively good fit we suggest this to be a result of the anthropogenic influence on coastal marine ecosystems existing today at the majority of the coastal sample sites in the reference dataset as a result conditions at these sites do not correspond to pre industrial conditions we advise users of dinoflagellate cyst transfer functions to pay more attention to this aspect

quantitative estimation of fluid pressure ratio of shear vein in an on land accretionary complex the yokonami melange the cretaceous shimanto belt kochi southwest japan abstract the fluid pressure ratio and effective friction coefficient of shear veins in an exhumed accretionary complex in the cretaceous shimanto belt southwest japan were constrained by fluid inclusion and stress inversion analyses the shear veins are considered to be developed along the decollement temperature and pressure conditions for shear veins were found to be in the range of 175 225 c and 143 215 mpa respectively fluid pressure ranged between the lines of 70 100 lithostatic pressure when the geothermal gradient was assumed on the basis of the slab age at the trench the effective friction coefficient of shear veins was estimated to be 0 1 0 2 by stress inversion analysis which corresponds to a fluid pressure ratio of 0 67 0 83 both pressure temperature and friction coefficient results indicate that the fluid pressure ratio is higher than about 0 7 in this paper we propose the procedure to constrain paleo fluid pressure ratio from natural materials wedge states were examined using the weak decollement friction coefficient with shallow and steep taper angles indicating that the wedge state is stable or compressively critical and is controlled by the fluid pressure ratio within the wedge

the late holocene gargano subaqueous delta adriatic shelf sediment pathways and supply fluctuations the gargano subaqueous delta formed on the eastern and southeastern sides of the gargano promontory in the western adriatic this subaqueous deposit represents the southernmost portion of the late holocene highstand systems tract hst growing along the western side of the adriatic as an extensive wedge of deltaic and shallow marine mud the late holocene hst rests above a regional downlap surface that marks the time of maximum landward shift of the shoreline attained around 5 5 cal kyr bp at the end of the late pleistocene holocene sea level rise high resolution seismic stratigraphic and tephra correlation indicate the presence of a thin basal unit recording condensed deposition between 5 5 and 3 7 cal kyr bp over much of the basin above this unit sediment accumulation rates increased to high values as much as 1 5 cm yr 1 reflecting the stabilisation of relative sea level and the forcing from high frequency climatic or anthropogenic changes affecting river dynamics the late holocene mud wedge of which the gargano subaqueous delta is a significant component reaches up to 35 m in thickness and has a volume of ca 180 km3 the shore parallel thickness distribution of the mud wedge reflects the dominant oceanographic regime of the basin and the asymmetric location of the mostly western sediment sources with a combined modern delivery of 51 7 106 t yr 1 of mean suspended load in sections perpendicular to the coast the late holocene mud wedge appears composed of forestepping clinoforms with gently dipping foresets typically 0 5 the gargano subaqueous delta is characterised by a submarine topset in water depths shallower than 25 28 m and accounts for about 1 7th of the total volume of the late holocene mud wedge despite the absence of direct river supply to the gargano area in the area of maximum interaction between shore parallel currents and basin morphology progradation occurs onto a flat and barren bedrock outcrop in about 50 80 m water depth the rapid transition from a thickness of 30 m of late holocene mud to nil is a good indication of the role of southward flowing bottom hugging shelf currents in causing the redistribution of sediment along the adriatic inner shelf additional evidence of this regime comes from 1 the most recent sigmoid defined at seismic stratigraphic scale deposited since the onset of the little ice age showing a shore parallel thickness distribution and a main depocentre to the southeast of the gargano promontory 2 the maximum values of sediment accumulation rates over the last century documented by 210pb measurements defining a narrow shore parallel belt immediately seaward of the depocentre of the most recent sigmoid the gargano subaqueous delta grows from the outbuilding of progressively younger progradational sigmoids that tend to parallel the previous ones the gargano subaqueous delta differs from other documented late holocene subaqueous deltas because its growth reflects 1 sediment transport dominated by bottom currents sub parallel to the strike of the composing clinoforms 2 a complex supply regime including the po delta 350 km to the north and several coalescing apennine rivers acting as line source 3 several alternating intervals of enhanced outbuilding and condensed deposition and 4 an in phase growth of the most recent sigmoid with the major progradation of the po delta during the little ice age

cryptotephra from lipari volcano in the eastern gulf of taranto italy as a time marker for paleoclimatic studies we present the first tephroanalysis based on geochemical fingerprinting of volcanic glass shards from eastern apulian shelf sediments in the gulf of taranto italy high sedimentation rates in the gulf are ideal for high resolution paleoclimate studies which rely on accurate age models cryptotephrostratigraphy is a novel tool for the age assessment of marine sediment cores in the absence of discrete tephra layers high resolution quantitative analysis of glass shard abundance in the uppermost 45 cm of a gravity core identified two cryptotephras microprobe analysis of glass shards supported by an accelerator mass spectrometry 14c based age model identified the pronounced primary cryptotephra at 36 cm bsf below sea floor as the felsic ad 776 monte pilato eruption on the island of lipari whereas the thinner mafic tephra layer at 1 5 cm bsf is associated with the ad 1944 eruption of somma vesuvius identifying these tephra layers provides an additional 14c independent stratigraphic framework for further paleoclimatic studies allowing us to link mediterranean climate and hydrology to orbital variation and large scale atmospheric processes our results underline the importance of qualitative tephrostratigraphy in a highly geodynamic region where solely quantitative approaches have demonstrated to bear a high potential for false correlations between tephra layers and eruptions

distribution and stable isotopes of plant wax derived n alkanes in lacustrine fluvial and marine surface sediments along an eastern italian transect and their potential to reconstruct the hydrological cycle reconstructing terrestrial water budgets is of prime importance for understanding past climate and environment to shed more light on how plant wax derived n alkanes may be used for this purpose we investigated the distribution and stable isotopic compositions of hydrogen d and carbon 13c of plant wax derived n c29 and c31 alkanes in terrestrial coastal and offshore surface sediments in relation to hydrology along a nw se transect east of the italian apennines from the po river to the eastern gulf of taranto the plant wax average chain length increases southward and may relate to increasing temperature and or aridity the plant wax d of the terrestrial and coastal samples also increases southward and mainly reflects changes in the d of precipitation the 13c of plant waxes is primarily interpreted in terms of c3 vegetation changes rather than varying contributions by c4 plants the plant wax 13c d composition of the po river and apennine rivers differs considerably from that in southern italy and suggests a mainly southern source for plant waxes in marine sediments of the gulf of taranto this calibration provides a basis for the reconstruction of past changes in the italian water balance and n alkane source areas

origin and distribution of terrestrial organic matter in the nw mediterranean gulf of lions exploring the newly developed bit index the branched and isoprenoid tetraether bit index is based on the relative abundance of nonisoprenoidal glycerol dialkyl glycerol tetraethers gdgts derived from organisms living in terrestrial environments versus a structurally related isoprenoid gdgt crenarchaeol produced by marine crenarchaeota the bit index varies between 0 and 1 representing marine and terrestrial organic matter om end members respectively hopmans et al earth planet sci lett 224 107 116 2004 in this study the applicability of the bit index to trace terrestrial om is tested in combination with other organic parameters toc c n ratio 13corg total lipid and n alkane in the gulf of lions a river dominated continental margin of the western mediterranean we analyzed a variety of soils and riverbed sediments from the continent as well as surface sediments from the shelf and canyons the bit index in soils and riverbed sediments shows high values 0 9 while it varies between 0 02 and 0 83 in marine sediments decreasing seaward from the inner shelf to the slope for marine surface sediments high bit values are associated with lower 13corg values as well as higher toc contents and higher n alkane concentrations our results confirm that the bit index can be applied in coastal marine environments in order to characterize terrestrial om as proposed by hopmans et al 2004 therefore the bit index is a useful addition to the proxies presently available for studying the origin and distribution of om in continental margins and especially valuable in multiproxy studies

geochemical and mineralogical variations as indicators of provenance changes in late quaternary deposits of se po plain combined geochemical and mineralogical characterisation of mudstone prone successions can provide suitable indicators of sediment provenance a case study from the late quaternary depositional sequence of southeastern po plain shows that major changes in geochemical and mineralogical composition can be ascribed to changes in sediment dispersal patterns occurring during the last 30 ka in response to fluctuating sea level the po river with a mixed contribution from the alpine and apenninic chains and its southern tributaries flowing from the apennines acted as the major feeders for the study area during the late quaternary chromium and nickel among trace elements and serpentine and dolomite among minerals appear as the major provenance indicators for the study succession allowing distinction of an apenninic chromium and serpentine poor province from a mixed alpine apenninic po related chromium and serpentine rich province the relatively low cr al2o3 and serpentine silicate ratios recorded in sediments of late pleistocene age 30 ka bp which accumulated at the last glacial maximum suggest that during lowstand times and early stages of transgression the southeastern po plain was beyond the po river influence being fed uniquely by rivers of apenninic provenance increasing cr al2o3 and serpentine silicate ratios recorded within back barrier transgressive deposits 8 10 ka bp in the comacchio and ravenna sectors reflect a major change in sediment supply taking place during the holocene when partially barred environments largely connected with the open sea became established in the study area and po derived detritus was delivered to estuaries and lagoons by littoral drift maximum chromium and serpentine values are recorded at peak transgression and during the following sea level highstand 6 ka bp present when sediment supply exceeded the rate at which new accommodation space was created leading to extensive po delta progradation the drop in cr al2o3 and serpentine silicate ratios recorded in some cores at top of the holocene succession reflects the local reestablishment behind the prograding po delta complexes of an alluvial plain drained by rivers of apenninic provenance as a result of distributary channel switching and delta lobe abandonment geochemical and mineralogical analyses show negligible compositional variations between pleistocene and holocene deposits landward of the line of maximum marine incursion especially close to the basin margin in these instances sample composition throughout the entire stratigraphic succession clearly suggests an ongoing supply from the adjacent apenninic chain comparison with sand compositional analyses from major sand bodies of the same stratigraphic succession highlights the complementary but fundamental role of geochemical and mineralogical characterisation of clays for provenance research

climate controlled multidecadal variability in north african dust transport to the mediterranean high resolution laser ablation inductively coupled plasma mass spectroscopy scanning of resin embedded laminated sediments is used to detail variability in the composition and magnitude of recent eolian dust deposition in the eastern mediterranean the composition of dust accumulating in the anoxic atalante basin varies in response to the strength of the summer blocking mode of mediterranean climate dust sources located upwind on the westerly airflow are favored during phases of weaker blocking hence stronger summer westerlies this mode is in turn correlated to the pronounced multidecadal oscillation in mediterranean sea surface temperature related to the atlantic multidecadal oscillation suggesting that coupled ocean atmosphere dynamics control the large scale transport of dust in the region variable precipitation in dust source regions may also exert an influence on the relative flux of dust from each source and hence the net composition of dust deposited in the basin persistent oscillations in the composition of deeper sediments indicate that the basin offers a high potential archive for reconstruction of climate controlled variability in dust transport prior to the instrumental era

dense low salinity outflow from the adriatic sea under mild 2001 and strong 1999 winter conditions 1 quasi synoptic temperature salinity and oxygen measurements in the adriatic and northern ionian seas mediterranean sea during two different winter conditions are presented in addition to the confirmation of previous knowledge about deepwater formation in the eastern mediterranean measurements give more insight into processes in the adriatic sea in winter and especially into the fate of the dense low salinity water masses transported by the west adriatic current wac and its spreading into the ionian sea a mild winter season without dense water production in the shallow areas of the adriatic sea was encountered during a cruise in february 2001 dense water outflow restricted to the deeper parts of the strait of otranto was nevertheless present during that mild winter and also in previous records of a cruise in autumn 1999 thus even in times of no deepwater production in the southern adriatic sea observations reveal a continuous flow of adriatic deep water adw through the strait of otranto and downslope in the northern ionian sea strong winter conditions are represented by a cruise carried out in february 1999 at that time cold and fresh water with density higher than that of south adw was observed on the italian shelf the dense coastal current is continued around cape santa maria di leuca at the heel of the italian boot in the gulf of taranto where the width of the shelf rapidly decreases dense coastal water is released to depth and transformed by intrusion and mixing with ambient water plumes and patches with horizontal extensions smaller than distances of a station grid are resolved by towed measurements in the 200 m upper layer with a multisensor chain products of coastal water transformation may be found at any depth on the western slopes of the ionian sea the new observations of dense water carried by the wac and plunging down to the level of neutral buoyancy in the gulf of taranto seem to confirm the hypothesis that the wac could be the origin of cold lenses found below the thermocline in the central ionian sea sellschopp and onken 2000

core top calibration of δ18o and δ13c of g ruber white and u mediterranea along the southern adriatic coast of italy we carried out an extensive survey of the oxygen and carbon isotope composition of the planktic species g ruber white and of the benthic species u mediterranea along the southern italian coast of the adriatic sea and in the gulf of taranto comparison with seasonal satellite based sea surface temperature maps and water column profiles as well as with several sets of water samples allows estimation of the effect of salinity and different nutrient supply on the 18o and 13c of foraminifera the results indicate that g ruber white while being highly affected by different salinity and nutrient distributions related to circulation patterns of major water masses dominantly record summer temperature conditions u mediterranea reflect the recent environmental conditions such as nutrient supply and bottom water temperature characteristics along the southern italian coast and clearly show the transition from a near coastal eutrophic system to an offshore oligotrophic system

geochemistry and particle size of surface sediments of gulf of manfredonia southern adriatic sea abstract in this study we describe mechanisms influencing the spatial distribution of the surface sediments in the gulf of manfredonia seventy three samples were collected on a regional grid and analyzed for grain size major and trace elements and organic matter content sediments contain marine derived carbonate as well as terrigenous fractions indicating highly heterogeneous sediment composition dictated by different provenance and complex transport processes principal component analysis provides information about processes involved in the formation and dispersal of the sediments the regional sediment distribution is function of the gulf s morphology and sedimentary inputs from fluvial sources mainly from the ofanto river and from the north and central adriatic basin biogenic carbonate reefs identified in two restricted coastal areas add complexity to sediment shelf dispersal the north adriatic current flowing southward transports and deposits sediments from the northern basin in the offshore area of the gulf while an inner anticyclonic current distributes and mixes northern and fluvial sediment with a clockwise pattern in order to better assess the fluvial contribution also bedload samples from the main river debouching into the gulf were sampled enabling the identification of geochemical indexes to distinguish the role of both fluvial inputs and hydrodynamic processes affecting solid particles dispersion within the gulf this study provides a contribution to a qualitative estimate of the sediment supply entailed in the southwestern adriatic basin

glacial interglacial changes in southern africa compound specific δ13c land plant biomarker and pollen records from southeast atlantic continental margin sediments this is part 2 of a study examining southwest african continental margin sediments from nine sites on a north south transect from the congo fan 4 s to the cape basin 30 s representing two glacial mis 2 and 6a and two interglacial stages mis 1 and 5e contents distribution patterns and molecular stable carbon isotope signatures of long chain n alkanes c27 c33 and n alkanols c22 c32 as indicators of land plant vegetation of different biosynthetic types were correlated with concentrations and distributions of pollen taxa in sediments of the same time horizons selected single pollen type data reveal details of vegetation changes but the overall picture is best illustrated by summing pollen known to predominantly derive from c4 plants or c4 plus cam plants the c4 plant signals in the biomarkers are recorded in the 13c data and in the abundances of c31 and c33n alkanes and the c32n alkanol calculated clusters of wind trajectories for austral summer and winter situations for the holocene and the last glacial maximum afford information on the source areas for the lipids and pollen and their transport pathways to the ocean this multidisciplinary approach provides clear evidence of latitudinal differences in leaf wax lipid and pollen composition with the holocene sedimentary data paralleling the current major phytogeographic zonations the northern sites congo fan area and northern angola basin get most of their terrestrial material from the congo basin and the angolan highlands dominated by c3 plants airborne particulates derived from the western and central south african hinterland dominated by deserts semideserts and savannah regions are rich in organic matter from c4 plants as can be expected from the present and glacial positions of the phytogeographic zones the carbon isotopic signatures of n alkanes and n alkanols both become isotopically more enriched in 13c from north to south in the northern part of the transect the relative importance of c4 plant indicators is higher during the glacials than in the interglacials indicating a northward extension of arid zones favoring grass vegetation in the south where grass rich vegetation merges into semidesert and desert the difference in c4 plant indicators is small

fine sediment mass balance in the western adriatic continental shelf over a century time scale abstract to obtain a quantitative estimate of the sediment accumulating on the muddy belt extending along the western adriatic continental shelf a budget was calculated based on the mass accumulation rates measured from more than one hundred activity depth profiles of 210 pb 137 cs depth distributions were used when possible to support 210 pb results 210 pb profiles show quasi monotonic declines in the foreset region of the central adriatic clinoform in the prodelta of the rivers po and isonzo 210 pb profiles are characterized by intervals of low and uniform activity which are thought to be produced by flood deposition since the north adriatic is shallow and occasionally affected by storms from bora wind sediments are not in steady state and their accumulation is the net result of recurring deposition resuspension and winnowing events in the western adriatic mass accumulation rates range between 0 04 and 6 6 g cm 2 yr 1 peak values were recorded in the po and isonzo prodeltas and along a narrow belt between pescara and the gargano promontory furthermore the latter depocentre is located immediately seaward of the offlap break 40 50 m water depth and parallels that of the most recent sigmoid of the hst the integration of mass accumulation rates throughout the mud wedge of the north and central adriatic gave a value of 42 0 tg yr 1 of sediment accumulating along the italian coast the balance between sediment accumulation and riverine sediment supply 46 6 tg yr 1 suggests an export of 4 6 tg yr 1 to the south adriatic basin and or the mediterranean sea the along shore sediment transport is very effective and in particular 16 2 tg yr 1 of sedimentary material 35 of the riverine supply is transferred from north to central adriatic through the ancona section

major and trace elements of stream sediments from the lowermost amazon river geochemical results from river bottom sediments taken from the lowermost amazon river are presented bedload sediments were analyzed for 10 major and 38 minor elements mud bulk sediments exhibit a tendency to a slight enrichment in cr mn rb sr zr cs ba and hf pointing to the importance of these elements in the silt fraction generally cu zn rb cs ba and sn are clearly associated with clay minerals while y zr hf th and u are associated with heavy minerals the location of this area in an intensive chemical weathering environment results in the strong modification of sediment composition chemical weathering processes strongly modify original sediment composition and can be recognized apart from provenance processes on the basis of their geochemical signature discriminant analysis makes the detection of less marked differences in sediment characteristics possible thus improving the accuracy of distinctions between groups the amazon mouth and xingu mouth xm are discriminated principally by the textural maturity of their sediments the jari mouth jm shows highest co and fe2o3 contents despite similarities between the amazon north branch anb and amazon south branch asb the anb can be differentiated on the basis of its higher sr p2o5 and na2o contents the asb on the basis of its higher zn mno and cao contents and the estreitos de breves est based on its higher abundance of ni and cu higher contents in p2o5 fe and mn are related to laterite covers

the 5 5 4 5 kyr climatic transition as recorded by the sedimentation pattern of coastal deposits of the apulia region southern italy coastal marine holocene deposits of the apulia region considered as indicators of palaeoclimatic conditions were studied our data show that 1 up to c 5500 cal yr bp a phase of accumulation of flint pebbles from the gargano headland occurred at the riviera sud di manfredonia adriatic coast their transport from the gargano headland north of the study site is incompatible with the current northward littoral drift and is best explained by a prevalence and dominance of ne and e winds and 2 after c 4500 cal yr bp there was a rapid accumulation of sediments at the marina di ugento ionian coast which is best explained by a prevalence and dominance of s sw and se winds the two different wind regimes identified can be explained by a change in the mean pressure configuration in the central mediterranean the first phase until c 5500 cal yr bp consisted of more frequent cyclogenesis to the east southeast of the italian peninsula followed by a second phase from c 4500 cal yr bp of more

unraveling north african riverine and eolian contributions to central mediterranean sediments during holocene sapropel s1 formation hydroclimate variability has exerted a fundamental control on the alternating deposition of organic lean marl and organic rich sapropel sediments in the eastern mediterranean sea ems however the exact mechanisms regarding the freshwater sources and related changes are still debated here sr and nd isotopes and high resolution elemental data are used to constrain different riverine and eolian supplies to the central mediterranean over the past 9 8 ka the detrital sediments in core cp10bc taken at the margin of the libyan shelf in the southwestern ionian sea can be described by a three endmember mixing system based on sr and nd isotopic compositions the same systematics can also be deduced from ti and k compositional variability the endmembers comprise saharan dust aegean nile and libyan soil representing the eolian supply from north africa the riverine inputs from the aegean nile areas as well as the riverine and shelf derived fluxes from the libyan tunisian margin respectively for the sapropel s1 period in particular we find important detrital supplies from fossil river wadi systems along the libyan tunisian margin activated by intensified african monsoon precipitation combining the temporal profiles with the consistent variability observed in the 87sr 86sr 1000 sr diagram such libyan contribution has been most prominent during the uppermost period of sapropel s1 in core cp10bc this observation is in agreement with hydroclimate reconstructions of northwestern libya comparison of the sr nd isotope data between core cp10bc and four cores taken along a west east transect throughout the ems shows that this detrital supply originated mainly from western libya tunisia and was transported as far eastward as 25 e while being diluted by an increasing nile contribution

core top calibration of the lipid based u37k and tex86 temperature proxies on the southern italian shelf sw adriatic sea gulf of taranto abstract the mediterranean sea is at the transition between temperate and tropical air masses and as such of importance for studying climate change the gulf of taranto and adjacent sw adriatic sea are at the heart of this region their sediments are excellently suited for generating high quality environmental records for the last millennia with a sub decadal resolution the quality of these records is dependent on a careful calibration of the transfer functions used to translate the sedimentary lipid signals to the local environment here we examine and calibrate the u 37 k and tex 86 lipid based temperature proxies in 48 surface sediments and relate these to ambient sea surface temperatures and other environmental data the u 37 k based temperatures in surface sediments reflect winter spring sea surface temperatures in agreement with other studies demonstrating maximum haptophyte production during the colder season the tex 86 based temperatures for the nearshore sites also reflect winter sea surface temperatures however at the most offshore sites they correspond to summer sea surface temperatures additional lipid and environmental data including the distribution of the bit index and remote sensed chlorophyll a suggest a shoreward increase of the impact of seasonal and spatial variability in nutrients and control of planktonic archaeal abundance by primary productivity particle loading in surface waters and or overprint by a cold biased terrestrial tex 86 signal as such the offshore tex 86 values seem to reflect a true summer signal to the effect that offshore u 37 k and tex 86 reconstruct winter and summer temperature respectively and hence provide information on the annual temperature amplitude

stratigraphic framework of the apulian deep water coral province ionian sea abstract shallow sediment lithology and stratigraphy were investigated at selected areas off santa maria di leuca sml on the apulian margin between 350 and 1200 m water depth in order to define the sea bottom character on which coral mounds have developed according to existing geophysical data and in situ observations deep coral growth in the sml area creates patches of colonies typically settled on hard substrates on the upper flanks and or near the top of mound like structures and elongated ridges the sedimentary stratigraphy is strongly influenced by the local topography which is modeled by tectonic and geomorphological forcing large scale erosional features slope failure and sediment mass accumulation are evident from seismic investigations additionally sites of preferential sediment accumulation due to the action of bottom currents are identified as a result a complex sedimentary pattern characterizes this part of the apulian margin with strong lateral variability in sediment type and age although hemipelagic silty clay constitutes the main lithology there are sites characterized by periodic accumulation of silt and fine sand and local re deposition of coarse biogenic sand from the surrounding areas and from shallower depths excluding one site where mid pleistocene sediments are brought very close to the bottom surface due to wide scale erosion all collected sediments are late pleistocene to holocene in age and fall biostratigraphically within the emiliania huxleyi acme nannofossil zone reworking detected through nannofossil analysis is common in most cores excluding the ones taken from topographic highs and is variable in extent from site to site and within the sediment column it includes cretaceous to early pleistocene species suggesting provenance from extended successions or various stratigraphic levels outcropping on the submerged apulian margin or in adjacent land sections reworking is often associated with a high content of lithogenic particles and an increase in the coarser silt fraction coral debris was collected at many stations both at the sediment surface and within the stratigraphic sequence with varying abundance in relation to proximity to the coral colonies radiometric dating and micropaleontological analyses at some sites allow us to propose a sequence of coral colonization phases

the glacial interglacial transition and holocene environmental changes in sediments from the gulf of taranto central mediterranean abstract an extensive high resolution sedimentological geochemical survey was done using geo acoustics xrf core scans icp aes ams 14c dating and grain size analyses of sediments in 11 cores from the gulf of taranto the southern adriatic sea and the central ionian sea spanning the last 16 cal ka bp comparable results were obtained for cores from the gallipoli shelf eastern gulf of taranto and the southern adriatic sea suggesting that the dominant provenance of gallipoli shelf sediments is from the western adriatic mud belt the 210pb and 14c dated high accumulation rate sediments permit a detailed reconstruction of climate variability over the last 16 cal ka bp although the glacial interglacial transition is generally dry and stable these conditions are interrupted by two phases of increased detrital input during the bolling allerod and the late younger dryas the event during the younger dryas period is characterized by increased sediment inputs from southern italian sources this suggests that run off was higher in southern compared to northern italy at approximately 7 cal ka bp increased detrital input from the adriatic mud belt related to sea level rise and the onset of deep water formation in the adriatic sea is observed and is coincident with the end of sapropel s1 formation in the southern adriatic sea during the mid to late holocene we observed millennial scale events of increased detrital input e g during the roman humid period and of decreased detrital input e g medieval warm period these dry wet spells are consistent with variability in the north atlantic oscillation nao a negative state of the nao and thus a more advanced penetration of the westerlies into the central mediterranean that result in wet conditions in the research area concord with events of high detrital input e g during the roman humid period in contrast a positive state of the nao resulting in dry conditions in the mediterranean dominated during events of rapid climate change such as the medieval warm period and the bronze age

biogenic barium and the detrital ba al ratio a comparison of their direct and indirect determination biogenic barium concentrations obtained from direct determination by a three step sequential extraction procedure are compared to those obtained from the widely used indirect normative calculation based on total digestion a comparison of the biogenic barium from the direct sequential extraction and the indirect normative calculation clearly shows that the detrital ba al ratio is the critical factor in the normative approach and that erroneous assumptions based on this ratio may introduce significant errors to the calculated biogenic barium overall the crustal average ba al ratio of 0 005 0 01 is much higher than our directly determined global average of 0 0037 this would result in an underestimation of the biogenic barium and thus of the primary productivity calculated using the ba flux obtained from the normatively calculated ba record using our ba al det ratio of 0 0037 leads to normatively calculated biogenic barium results that are in reasonable agreement with the biogenic barium from sequential extraction for samples of the atlantic pacific and indian ocean our directly determined regional ba al det ratios deviate from those calculated or assumed from hinterland ratios and our global average ba al det is lower than the one commonly reported therefore in sediments with a significant terrigenous fraction the sequential extraction technique is always required

geochemical variability induced by entrainment sorting quantified signals for provenance analysis abstract a substantial part of the mineralogical and chemical heterogeneity of clay poor sands at the bed scale results from tractive redistribution of the grains in the bedload since coarse and light particles are more easily entrained than denser and smaller heavy minerals the latter commonly concentrate in grain scale lags that alternate with sand depleted in these minerals when sampled and analysed at the centimetre scale this primary heterogeneity translates into nice geochemical covariations between the minor trace elements that concentrate in some heavy minerals zr ti p cr v y ce among others regressing these variations allow us to derive two chemical fingerprints of the sand one records the proportions between some heavy minerals the other the average composition of framework grains i e a sand composition corrected from the contribution of heavy minerals both relate to provenance and allow different sand beds to be compared in appropriate spider diagrams the construction of these diagrams their potential use and their limitations are discussed using two contrasting examples continental channel sandstones from the ravenscar group middle jurassic yorkshire uk illustrate how these geochemical fingerprints vary from the local to the group scales and how robust they are against diagenetic overprint at ravenscar the zr vs ti v cr covariations record the presence of ti oxides and magnetite together with zircon and of volcanic lithoclasts at the deposition stage despite a high degree of diagenetic alteration overbank sandstones lateral to channels from the deep marine gres d annot formation eocene oligocene alps illustrates how apatite and monazite delivered by a dominantly granitic source generate covariations between zr and p y ce and th contents with characteristically steep slopes

seasonality variations in the central mediterranean during climate change events in the late holocene abstract holocene rapid climate change rcc events such as the little ice age lia are thought to have influenced average annual temperatures only marginally but to have affected winter temperatures relatively strongly with summer temperatures relatively unaffected reconstructing climate change at a seasonal resolution is crucial to fully capture holocene climate variability mediterranean climate is highly seasonal being influenced by the subtropical high pressure belt in summer and the mid latitude westerlies combined with outbreaks of polar winds in winter we identified events of high and low detrital input to the gulf of taranto central mediterranean sea anticipated to be linked to humid and dry conditions respectively and thereby potentially reflecting seasonal contrasts these events represent the bronze age ba roman humid period rhp medieval climate anomaly mca lia and present day and were selected for the analysis of single specimen globigerinoides ruber white carbonate chemistry mg ca 18o and 13c the dynamic range found for these parameters for the measured single individuals in the most recent interval reflects the present day seasonal contrasts in temperature and precipitation albeit with a bias towards the summer season these results are compared with high resolution 15 years sample sea surface temperature sst and bottom water temperature bwt reconstructions based on the 18o of g ruber white and mg ca of benthic foraminifer hyalinea balthica although the seasonal temperature contrast remains relatively stable significant winter cooling is observed during the ba and lia connections between high latitude climate winter conditions and low latitude climate summer conditions appear not straightforward during rcc events this results in changes in the moisture balance and in shifts in seasonal dominance between rccs during the lia winter like conditions cold and humid prevail throughout the year in contrast winters are dry and cold during the ba and are accompanied by dry and warm summers suggesting year round aridity and a relatively high seasonal temperature contrast this could have had a profound impact on early agriculture in southern italy

shelf edge erosion sediment failure and inception of bari canyon on the southwestern adriatic margin central mediterranean abstract we investigate the impact of regional tectonic setting and sedimentary dynamics on the onset of bari canyon the main sediment conduit on the southwestern adriatic margin sam since the middle pleistocene deposition on the sam a foreland basin relative to the southern apennines was primarily controlled by glacio eustatic cycles however a number of tectonic structures active since the early cenozoic impacted on the stacking of progradational deposits and on the overall slope setting and stability along the sam four depositional sequences accomplished the progradation of the shelf margin between ca 450 kyr bp and the last glacial maximum lowstand ca 20 ka bp these sequences are variably dissected by two large scale erosional features on the upper slope 1 bari canyon and 2 gondola slide headscarp further north the shelf facing these two major erosional structures shows several smaller scale incisions that merge with the sequence boundaries between each of the four stacked depositional sequences the distribution of these erosional features reflects the location of tectonic structures that are still active suggesting that both the intense erosion and the sediment failure in these areas were enhanced by tectonic deformation we define the age of these older episodes of shelf edge erosion and mass wasting that were conducive to the inception of bari canyon as we know it today moreover we envisage the following predisposing factors as responsible for the inception and subsequent evolution of bari canyon a long term regional uplift and margin tilt likely controlling the lateral variability in shelf width and shelf slope profile b rapid margin progradation during the deposition of middle late pleistocene sequences c recent tectonic deformation resulting in gentle folds growing during the canyon evolution

latitudinal and downcore 0 750 ka changes in n alkane chain lengths in the eastern equatorial pacific abstract the n alkane c 31 c 29 c 31 ratios from surface sediments in the eastern equatorial pacific eep exhibit higher values to the north and lower values to the south across the southern edge 2 4 n of the intertropical convergence zone itcz since plants tend to synthesize longer chain length n alkanes in response to elevated temperature and or aridity the higher c 31 c 29 c 31 ratios at northern sites suggest a higher contribution of vegetation under hot and or dry conditions this is consistent with the observation that northern sites receive higher levels of plant waxes transported by northeasterly trade winds from northern south america where hot and dry conditions prevail furthermore from a sediment core covering the past 750 ka core hy04 4 n 95 w we found that c 31 c 29 c 31 ratios exhibit a long term decrease from mis marine oxygen isotope stage 17 to 13 during this period the zonal sst sea surface temperature gradient in the equatorial pacific increased suggesting an increase in walker circulation such intensified walker circulation may have enhanced moisture advection from the equatorial atlantic warm pool to the adjacent northern south america causing arid regions in northern south america to contract which may explain long term decrease in n alkane chain lengths

provenance of surface sediments along the southeastern adriatic coast off italy an overview multi proxy studies are necessary to understand sediment composition and related provenance on continental shelfs here it is shown that the spatial distribution of geochemical composition and grain size for surface sediments along the southeastern italian coast is related to provenance and mechanisms influencing sediment pathways a northern adriatic italian provenance can be distinguished from a southern apennine river source this is done independent of grain size using the element ratios ce ni and zr cr furthermore the origin of organic matter is determined using bulk carbon isotopes and the c n ratio integrating these results with those from complementary studies on 18o and 13c of globigerinoides ruber white the bit index stable isotopes of plant waxes and dinoflagellate cyst distribution from the same set of samples reveals that sediments from the northwestern adriatic are transported as far southward as the gallipoli shelf eastern gulf of taranto by the western adriatic current wac along the wac there is a consistent southward decrease in po river northern apennines provenance and a concomitant decrease in terrestrial soil organic matter om whereas the percentage of marine om increases the provenance for gallipoli shelf sediments is for 80 attributed to po river northern apennines sources and for 20 to southern italian sources om in the eastern gulf of taranto contains more marine om than other areas within the wac whereas om and sediments from the western part of the gulf of taranto have a more local riverine provenanc

palaeoenvironments of deposition of neogene laminated diatom mat deposits from the eastern equatorial pacific from studies of benthic foraminifera sites 844 849 851 abstract massive sedimentation of mats of the diatom thalassiothrix longissima forming laminated diatom mat deposits ldm occurred intermittently in the equatorial pacific throughout the neogene from at least 15 to 4 8 m y ago the background deposition was otherwise calcareous nannofossil diatom ooze no benthic foraminifera have been used to reconstruct the benthic environment of deposition and the role of both surface waters as a source of food and bottom waters including their corrosivity during ldm deposition three ldm events were studied site 844 11 4 ma early tortonian site 849 4 8 ma early zanclian and 6 6 6 8 ma early messinian a control section of no spanning the 4 8 ma event was studied from site 851 in addition the carbonate high no immediately preceding the 4 8 ma event was examined in site 849 from the foraminiferal evidence it can be shown that the ldm was deposited under conditions of normal oxygenation because infaunal taxa are present throughout and there was an increase in epifaunal taxa such as cibicides spp however there was a reduction in test size probably because only those smaller than 250 m were able to move through the restricted sediment pore spaces caused by the diatom mat meshwork the rate of accumulation of tests is highest in ldm interval and may reflect reduced predation from macrofaunal endobenthos among the epifaunal taxa nuttallides spp show a decrease in abundance in the ldm and even immediately preceding it this may be linked to a greater influence of corrosive aabw species known to feed opportunistically on phytodetritus epistominella exigua and alabaminella weddellensis are common in both no and ldm the increased relative abundance of a weddellensis in the ldm may be due to this species being smaller than e exigua and better able to exploit the food resource within the restrictive mat meshwork the foraminiferal results corroborate the previous interpretation that preservation of lamination in the ldm is due to the physical exclusion of macro endobenthos rather than oxygen depletion of the bottom waters

organic matter origin and distribution in suspended particulate materials and surficial sediments from the western adriatic sea italy abstract in this study organic carbon oc total nitrogen tn stable carbon isotopic 13 c oc and cuo reaction product compositions were used to identify the sources of organic matter om and to quantify the relative importance of allochthonous and autochthonous contributions to the western adriatic sea italy suspended particulate material 195 samples and surficial sediments 0 1 cm 70 samples from shallow cross shelf transects were collected in february and may 2003 respectively vertical water column profiles were acquired along the same transects data include depth potential temperature salinity density and chlorophyll fluorimetry along the western adriatic shelf in the near shore region the phytoplankton growth was influenced by dynamics of the buoyant plumes from the po and appennine rivers a small amount of very fine terrigenous material remained suspended within the coastal current and was exported southward along the shelf to the slope high variability in the bulk composition was detected in the po prodelta surficial sediments whereas the western adriatic shelf although a larger area exhibited a narrower range of values a significant decoupling was observed between suspended particles in the water column and surficial deposits the organic material collected in the water column was compositionally heterogeneous with contributions from marine phytoplankton riverine estuarine phytoplankton and soil derived om frequent physical reworking of surficial sediments likely leads to the efficient oxidation of marine oc resulting in the observed accumulation and preservation of refractory soil derived oc delivered by the po and appennine rivers

geochemical compositions and provenance discrimination of the central south yellow sea sediments geochemical compositions and sedimentation rates of surface and core sediments in the central south yellow sea were analyzed for the identification of sediment origins the sediment accumulation rates measured by 210 pb geochronology decrease significantly from the western part to the central area calcium carbonate total organic carbon and most elements are more enriched in the western muddy sediments than in the sandy eastern part overall geochemical compositions of the central south yellow sea sediments vary between those of chinese and korean river sediments supplied into the sea although caco3 content exhibits regional variations in the central south yellow sea the discrimination diagram of sc al vs cr th distinctly suggests that the muddy holocene sediments in the central western part are derived ultimately from chinese rivers especially the huanghe river whereas the eastern sandy sediments primarily came from the korean rivers during the postglacial transgression 2007 elsevier b v all rights reserved

high resolution bathymetry and acoustic geophysical data from santa maria di leuca cold water coral province northern ionian sea apulian continental slope abstract a total of 800 km 2 of multibeam echo sounder coverage roughly 800 km of chirp sonar data and 18 km of side scan sonar profiles 100 500 khz were acquired a few km offshore santa maria di leuca south eastern italy from 200 m to 1300 m water depth the explored area belongs to the upper slope of the gently south eastward dipping apulian continental margin northern ionian sea acoustic datasets were collected by three different oceanographic expeditions where evidence of living cold water coral cwc colonies were documented by previous surveys and samples high resolution multibeam bathymetry indicated an extensive rough seafloor with an irregular faulted upper surface to the west reflecting large scale tectonic control on the margin and a highly disrupted upper slope formed by prominent downslope mass movements to the north a broad area in the east was influenced by mass transport deposition which resulted in a very complex hummocky seafloor mainly shaped by detached block like features and failure related bedforms i e low scarps downslope lineations and compressional ridges from the shallow seismic stratigraphic data failure events appeared to be multiple and recurrent and chaotic reflectors both buried and exposed at the seafloor affected most of the investigated area drift sedimentation was also recognised along a central large ridge resulting in an interplay between contour currents and downslope turbidity currents the spatial distribution of the cwc reefs was inferred from the acoustic facies interpretation based on video images and ground truthed by sediment samples it appeared that 1 within the investigated area living coral frameworks were located along large topographic highs facing the main flow of the bottom currents where hard and firm substrata and or failure related sediment bedforms occurred 2 cwc mainly settled on clustered and isolated mound like features tens to a few hundreds of metres long and no more than 25 m high and were located between 600 and 900 m water depth within the broad area affected by downslope mass transport deposits such mound like morphologies could thus be interpreted as a result of sediment accreted by coral growth with the consequent sediment trapping on small scale positive seafloor irregularities formed by different types of pleistocene exposed mass transport deposits their burial prevented by bottom currents

distribution of exchangeable fixed organic and total nitrogen in interbedded turbiditic pelagic sediments of the madeira abyssal plain eastern north atlantic abstract nitrogen compounds in the interbedded turbiditic pelagic sediments of the madeira abyssal plain from hereon map have been divided in separate extracted fractions such as exchangeable nitrogen nex fixed nitrogen nfix and organic nitrogen norg nex is found to be directly proportional to the amount of organic matter corg in the sediment and is not related to the amount of ammonium in the porewater only at a relatively low corg content is the nex determined by the mineralogy of the sediment the norg as determined from norg ntot nfix nex is strongly related with corg the nfix content and the n fix al ratio for organic rich sediments are high compared with other sediments and have not changed upon post depositional oxidation of the organic matter post depositional oxidation of organic matter through oxygen does lead to a decrease in the c n ratio of the remaining organic matter in the organic rich turbidites the c n ratio calculated for the organic matter that has been decomposed through oxygen is similar to that calculated through stoichiometric modelling for decomposition under reducing circumstances c n ratios of 17 and 18 respectively this implies that for the sediments of the map the c n ratio is identical for organic matter decomposed under oxygenated and under reducing conditions

riverine supply to the eastern mediterranean during last interglacial sapropel s5 formation a basin wide perspective abstract organic rich sapropel sediments were repeatedly deposited in the eastern mediterranean sea ems in response to insolation driven freshwater forcing however the exact freshwater sources and causal associated paleoclimate related processes remain unresolved sapropel s5 formed during the insolation maximum of the last interglacial is one of the most intensely developed sapropels of the late quaternary here detrital sediments of sapropel s5 obtained from 8 cores together with 13 ems surface samples are analyzed for major elements rare earth elements ree and sr and nd isotopes this permits a basin wide investigation of the source and distribution of river borne material to the ems for sapropel s5 and its comparison to the present day and the holocene sapropel s1 period during the sapropel s5 there was minor saharan dust input the marked east west geochemical gradient in s5 detrital sediments across the ems is therefore attributed to mixing between fluvial contributions being nile discharge aegean adriatic riverine inputs and libyan tunisian paleodrainage fluxes the offshore distribution of nile sediments during sapropel s5 was comparable to those during s1 and the present the nile sediment contribution appears to be only dominant for the levantine basin decreasing to negligible values south of crete this rather limited sediment delivery despite inferred increased runoff during s5 is related to denser vegetation cover on the ethiopian highlands by contrast small rivers around the aegean and adriatic sea brought large amounts of detrital material into the ems this is particularly noticeable around crete and the northern ionian sea the enhanced riverine input is probably due to strong precipitation seasonality over the northern ems borderlands particularly for the early phase of the last interglacial maximum furthermore there are substantial fluvial contributions from the libyan tunisian margin to the ionian sea sediments in particular during the last part of sapropel s5 the inferred river borne material was transported via paleodrainage systems reactivated by intensified monsoon precipitation and derived from central saharan mountains compared to sapropel s1 these s5 related paleodrainage fluxes were not only stronger but also had a more predominant provenance from eastern rather than western libya in addition a similar averaged endmember of saharan dust sources is revealed by ree signatures

dynamic surface water alterations during sapropel s1 preserved in high resolution shallow water sediments of taranto gulf central mediterranean abstract the high sedimentation rate and shallow water depositional depth of the sediments at site dp 30 in the gulf of taranto central mediterranean provide unique biogenic signals that are usually not preserved in deeper records this permits the reconstruction of long and short term surface water modifications across the sapropel s1 period 10 6 5 ka including calcareous nannofossil data at centennial scale resolution the peculiar patterns of key taxa allowed the recognition of distinct long to short term surface water changes that provide valuable evidence on climate conditions leading to sapropel deposition as a long term pattern s1 is marked by a distinct increase of helicosphaera carteri thought to reflect increased detrital input land derived nutrients in the surface water related to a higher influence of the western adriatic current a concomitant pattern of increased black organic particles in the sediments supports a connection between organic matter preservation at the seafloor and nutrient availability in the surface water decreased salinity in the surface water testified by an increase of braurudosphaera bigelowii develops from 9 2 up to 6 5 ka at higher frequencies additional changes occurred in surface subsurface waters during the formation of s1 at shallow depths starting from 11 ka the relative abundance pattern of florisphaera profunda indicates a gradual nutrient enrichment in the subsurface waters and the development of a deep chlorophyll maximum dcm which becomes well established at the onset of sapropel s1 between 10 and 9 ka a further change in the plankton ecosystem occurs between 9 and 8 2 ka when reduced coccolithophore production is concomitant with diatom occurrence and enhanced br ti level implying a productivity increase from 8 to 6 5 ka coccolithophore productivity is re established in relation to a reduction both in surface water stratification and turbidity nutrient availability characterizing the final phase of sapropel formation the turbidity in the surface waters was briefly reduced at 8 2 and 7 3 ka when also oxygen conditions at the seafloor improved a centennial variability in turbidity low light conditions in surface waters is evident across s1 and is illustrated by the abundance patterns of h carteri and gladiolithus flabellatus the occurrence of ascidian spicules also represents a distinct biotic signal across the s1 layer indicating an increase of shallow water biogenic carbonate or an aragonitic near coastal source surface water modifications at longer and shorter time scales accompanying the deposition of sapropel s1 in the gulf of taranto occurred nearly simultaneously and with a magnitude that is comparable to changes observed in s1 deposits in the central and eastern mediterranean basin and slope settings