new discoveries of mud volcanoes on the eastern mediterranean ridge data from two mud volcanoes discovered on the eastern mediterranean ridge are presented showing that these features have erupted episodically within historical time both volcanoes mark the site of active gas and fluid venting from deep within the sedimentary pile large volumes of mud breccia have been extruded onto the volcano slopes for the first time clasts up to c 1 m in size have been recovered from sea floor mud volcanoes the submarine clasts show lithologies ranging from shallow water bioclastic sandstones to marls and limestones dated using microfauna as oligocene miocene and perhaps cretaceous in age deep towed video footage of one of the volcanoes shows clasts up to several metres across within the crater area deep towed high resolution side scan sonar data and core data are presented to compare the two examples the paper documents the discovery of the two volcanoes the dublin mud volcano and the stoke on trent mud volcano the clasts that have been recovered from them the intermittence of the eruptions as interpreted from gravity core data and how the volcanoes contrast with other mud volcanoes further to the west

ice sheet sources of sea level rise and freshwater discharge during the last deglaciation we review and synthesize the geologic record that constrains the sources of sea level rise and freshwater discharge to the global oceans associated with retreat of ice sheets during the last deglaciation the last glacial maximum 26 19 ka was terminated by a rapid 5 10 m sea level rise at 19 0 19 5 ka sourced largely from northern hemisphere ice sheet retreat in response to high northern latitude insolation forcing sea level rise of 8 20 m from 19 to 14 5 ka can be attributed to continued retreat of the laurentide and eurasian ice sheets with an additional freshwater forcing of uncertain amount delivered by heinrich event 1 the source of the abrupt acceleration in sea level rise at 14 6 ka meltwater pulse 1a 14 15 m includes contributions of 6 5 10 m from northern hemisphere ice sheets of which 2 7 m represents an excess contribution above that derived from ongoing ice sheet retreat widespread retreat of antarctic ice sheets began at 14 0 15 0 ka which together with geophysical modeling of far field sea level records suggests an antarctic contribution to this meltwater pulse as well the cause of the subsequent younger dryas cold event can be attributed to eastward freshwater runoff from the lake agassiz basin to the st lawrence estuary that agrees with existing lake agassiz outlet radiocarbon dates much of the early holocene sea level rise can be explained by laurentide and scandinavian ice sheet retreat with collapse of laurentide ice over hudson bay and drainage of lake agassiz basin runoff at 8 4 8 2 ka to the labrador sea causing the 8 2 ka event

shredding of environmental signals by sediment transport 1 landscapes respond to climate tectonic motions and sea level but this response is mediated by sediment transport understanding transmission of environmental signals is crucial for predicting landscape response to climate change and interpreting paleo climate and tectonics from stratigraphy here we propose that sediment transport can act as a nonlinear filter that completely destroys shreds environmental signals this results from ubiquitous thresholds in sediment transport systems e g landsliding bed load transport and river avulsion this morphodynamic turbulence is analogous to turbulence in fluid flows where energy injected at one frequency is smeared across a range of scales we show with a numerical model that external signals are shredded when their time and amplitude scales fall within the ranges of morphodynamic turbulence as signal frequency increases signal preservation becomes the exception rather than the rule suggesting a critical re examination of purported sedimentary signals of external forcing citation jerolmack d j and c paola 2010 shredding of environmental signals by sediment transport geophys res lett 37 l19401 doi 10 1029 2010gl044638

chromium and nickel as indicators of source to sink sediment transfer in a holocene alluvial and coastal system po plain italy abstract a reliable quantitative estimate of changes in source to sink sediment transfer requires that high resolution stratigraphic studies be coupled with accurate reconstructions of spatial and temporal variability of the sediment routing system through time source to sink patterns from the contributing upland river catchments to the deltaic and coastal system are reconstructed from the holocene succession of the po plain on the basis of selected geochemical indicators sediment supplied to the delta area by the major trunk river the po exhibits naturally high cr and ni values which invariably exceed the maximum permissible concentrations for unpolluted sites this anomaly reflects remarkable sediment contribution from ultramafic ophiolitic parent rocks cropping out in the po drainage basin western alps and nw apennines in contrast alluvial and coastal plain deposits supplied by ophiolite free apenninic catchments invariably display lower cr and ni contents for constant sediment provenance domain cr and ni distribution is observed to be controlled primarily by hydraulic sorting clay silt deposits floodplain swamp and lagoon bay facies associations invariably show higher metal concentrations than their sandy counterparts fluvial channel distributary channel and beach ridge facies associations from a stratigraphic perspective in sedimentary basins characterized by strong differences in sediment composition geochemical fingerprinting of individual facies associations framed by surfaces of chronostratigraphic significance is proposed as an invaluable approach towards an accurate quantitative assessment of sediment storage in alluvial and coastal depositional systems as opposed to volumetric reconstructions based on lithologic or geometric criteria alone

shoreline response to autogenic processes of sediment storage and release in the fluvial system 1 experimentally determined shoreline migration rates show high frequency autogenic variability superimposed on low frequency allogenic shoreline responses induced by eustatic base level change this variability persists even when the shoreline migration is averaged laterally indicating time variation in total sediment discharge reaching the shoreline the magnitude of autogenic variability in shoreline migration rate changes by roughly a factor of 3 depending on the shoreline migration direction it is strongest during transgression when the shoreline is on average migrating against the mean sediment flow and weakest during regression when the shoreline is migrating with the mean sediment flow we propose that this time variation is due to overall sediment storage and release in the fluvial system we use a one dimensional geometric model to model the autogenic signals observed in the experiment the model uses small periodic changes in the fluvial slope to represent the effects of storage and release of supplied sediment due to intrinsic variation in the transport efficiency of the fluvial system the periodic pulses of sediment discharge to the shoreline required in the model to explain the variations in shoreline migration can exceed by an order of magnitude the mean allogenic sediment discharge the slope variability required in the model to explain the autogenic shoreline signals is 1 4 of the mean slope this is well within the range of observed variability in depositional fluvial slopes we propose that at least part of this observed variability is real that is the long profile slope of a depositional river system may have an intrinsic elasticity of a few percent of its mean value even under steady forcing autogenic slope variation of this magnitude could readily produce parasequence scale deposits in the stratigraphic record

worldwide initiation of holocene marine deltas by deceleration of sea level rise radiocarbon dated deltaic sequences of holocene age from different parts of the world began to accumulate within a restricted time range from about 8500 to 6500 years ago evaluation of major delta processes indicates that deceleration in sea level rise was the key factor in holocene delta formation within many deltas there is as much as a 2000 year age range between basal deposits in seaward and landward cores this age difference records the progressive landward migration of near mean sea level depositional environments during the lower to mid holocene establishment of a chronostratigraphic framework for holocene delta development provides a fundamental global baseline for distinguishing sea level change from vertical land motion by tectonism and isostasy and for evaluating rates of future marine incursion into low lying deltas

benthic ostracoda and foraminifera from the north adriatic sea italy mediterranean sea a proxy for the depositional characterisation of river influenced shelves abstract we investigated the distribution of ostracoda and benthic foraminifera from the shallow 20 m diversified meiofaunal assemblages occur with ostracoda discriminating sediment starved areas enriched in sand our results demonstrate that the combined use of ostracoda and benthic foraminifera represents a powerful tool for the depositional characterisation of river influenced shelves and to achieve detailed palaeogeographical reconstructions from shallow marine successions

separating natural and anthropogenic vertical movements in fast subsiding areas the po plain n italy case the geological and the anthropogenic components of vertical movement act on different time scales millions to thousands years and hundreds to tens of years respectively this peculiarity has been used in order to separate the factors controlling sea level changes in the po plain area the component due to long term geological processes is calculated from stratigraphic data commercial wells and seismic lines adding to this long term component the contribution of pleistocene deglaciation obtained from analytical models an estimate of the total natural component of vertical velocities is obtained the validity of these values is confirmed by comparison with velocities obtained from archaeological data and detailed palynological and paleontological analyses the anthropogenic components can be inferred by comparison between the total natural vertical velocities we calculate and vertical velocities obtained from other data sets two applications are proposed using tide gauge records and geodetic data respectively

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

millennial scale stratigraphy of a tide dominated incised valley during the last 14 kyr spatial and quantitative reconstruction in the tokyo lowland central japan spatial and quantitative analysis of infilling processes of the tide dominated incised valleys beneath the tokyo lowland during the last 14 kyr was undertaken by using data from 18 sediment cores 467 radiocarbon dates and 6100 borehole logs the post last glacial maximum valley fills consist of braided river meandering river estuary spit and delta systems in ascending order the boundary between the estuary and delta systems is regarded as the maximum flooding surface the maximum flooding surface beneath the tokyo lowland is dated at 8 ka in the arakawa valley and 7 ka in the nakagawa valley this age difference is due to the migration of the tone river from the arakawa valley to the nakagawa valley at 5 ka and suggests that the widely held view that the global initiation of deltas coincided with the abrupt rise of sea level at 9 to 8 ka is true only where there has been steady sediment supply from major rivers the meandering river system is dominated by sheet like sands that were deposited during lateral migration of channels during the younger dryas and isolated vertical sands within muds that reflect vertical aggradation of channels before and after the younger dryas the transition between these channel geometries is controlled by a threshold sea level rise of 4 to 7 mm yr 1 before migration of the tone river at 5 ka the tide dominated bay in the nakagawa valley was filled by upward fining laterally accreting muds the muds accreted from the margin to the axis of the bay such lateral accretion of suspended particles derived from outside the bay has been documented in other tide dominated coastal environments and is probably common in other similar settings after the migration of the tone river the bay was filled by upward coarsening deltaic sediments

understanding the origins of interannual thermocline variations in the tropical indian ocean 1 based on the data analysis of the 1000 hpa wind sst and ssh anomalies it is revealed that the atmospheric variations associated with indian ocean dipole iod or referred as indian ocean zonal dipole mode iozdm consist of a pair of anticyclones closely north and south of the equator with accompanying intense equatorial easterly anomalies while the atmospheric variations related to el nino southern oscillation enso include a strong anticyclone in the southeastern tropical indian ocean tio at higher latitudes with strong along shore wind anomalies near java sumatra coast the different atmospheric forcing patterns lead to the fact that oceanic thermocline variations associated with iod iozdm are more closely confined to the region north of 10 s while enso induced thermocline variations are dominant south of 10 s

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

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

composition and discrimination of sandstones a statistical evaluation of different analytical methods the discriminative power of four analytical approaches to sandstone composition is evaluated with respect to the separation of different formations and source areas the case study is cretaceous synorogenic sandstones litharenites from the eastern alps of europe which belong to four different formations and are derived from two source areas methods evaluated are light mineral analysis petrographic framework composition heavy mineral analysis major element xrf analysis and trace element xrf analysis the statistical parameters calculated percentages of well classified samples mahalanobis distance applying the logratio approach suggest that light mineral analysis has a significantly lower discriminative power than the other three methods taking into account the analytical expenditure for data acquisition trace element analysis appears to be the most efficient method for discrimination of at least the sandstone units examined although based on a single case study these results are interpreted to have a more general meaning with respect to sandstone discrimination based on composition concerning sandstone provenance trace element analysis provides a quick tool to estimate the discriminative potential of a sample suite i e the potential to discriminate between contrasting source areas if a provenance model already exists and discriminate functions between contrasting source areas are calculated trace element analysis is considered to be most efficient in correctly assigning an unknown sample to its source area these results cannot be extended to all kinds of sands and sandstones but they cast serious doubt on the belief that petrographic point count methods are the best approach to discriminate between sandstones

different impacts of various el nino events on the indian ocean dipole our early work wang and wang in j clim 26 1322 1338 2013 separates el nino modoki events into el nino modoki i and ii because they show different impacts on rainfall in southern china and typhoon landfall activity the warm sst anomalies originate in the equatorial central pacific and subtropical northeastern pacific for el nino modoki i and ii respectively el nino modoki i features a symmetric sst anomaly distribution about the equator with the maximum warming in the equatorial central pacific whereas el nino modoki ii shows an asymmetric distribution with the warm sst anomalies extending from the northeastern pacific to the equatorial central pacific the present paper investigates the influence of the various groups of el nino events on the indian ocean dipole iod similar to canonical el nino el nino modoki i is associated with a weakening of the walker circulation in the indo pacific region which decreases precipitation in the eastern tropical indian ocean and maritime continent and thus results in the surface easterly wind anomalies off java sumatra under the bjerknes feedback the easterly wind anomalies induce cold sst anomalies off java sumatra and thus a positive iod tends to occur in the indian ocean during canonical el nino and el nino modoki i however el nino modoki ii has an opposite impact on the walker circulation resulting in more precipitation and surface westerly wind anomalies off java sumatra thus el nino modoki ii is favorable for the onset and development of a negative iod on the frame of the bjerknes feedback

wavelet analysis of remote sensing and discharge data for understanding vertical ground movements in sandy and clayey terrains of the po delta area northern italy abstract subsidence phenomena change the proneness of urban and coastal areas to huge flooding particularly in river delta regions many natural and or anthropic processes can induce vertical ground movements identifying the causes of the observed phenomena is a useful even if not easy task for flood forecasting in order to improve the knowledge of natural versus anthropic contributions to vertical ground movements in the present work data analysis techniques polynomial regression analysis frequency analysis and cross wavelet and wavelet coherence analysis are used to analyze both the long and short time scale dependencies between continuous global positioning system cgps and variations of meteorological hydrogeological and hydrological data collected in the po river delta area northern italy from january 2009 to december 2015 the main findings are as follows i occurrence of positive correlations and periodic oscillations of about 2 3 years for all the analyzed meteorological hydrogeological and hydrological records ii a general decrease of the ground level with a faster soil lowering in clayey terrain with respect to sandy terrain and iii negative correlations between cgps and po river discharge records at the intra annual scale 2 6 months which are attributed to an isostatic rebound induced by the change of the river discharge due to precipitation changes over northern italy

parasequence types in shelfal mudstone strata quantitative observations of lithofacies and stacking patterns and conceptual link to modern depositional regimes mudstone strata have a vast variety of physical biogenic and chemical attributes at the lamina to bed scale approximately millimeters to decimeters thick our observations of more than 7 km of paleozoic to cenozoic mudstones revealed ordered patterns in this variety i e recurrent associations of lithofacies bedding style sedimentary structures and stratal architecture at bedset to parasequence scales approximately decimeters to meters thick we quantified characteristics of each association and their stacking patterns in vertical succession and linked them to sets of depositional processes most shelf mudstone strata appear to have accumulated in one of three facies association successions fass that can be related to depositional regimes through characteristic modes of sediment transport and accumulation as well as variations in benthic energy and oxygen levels we interpret these three fass as records of mud accumulation on different portions of continental shelves that were dominated by storm waves river floods or tidal currents each fas records a distinct parasequence type this approach can help fully integrate insights from oceanographic studies into more robust interpretations of the rock record and rock property maps

stepwise post glacial transgression in the rhone delta area as revealed by high resolution core data abstract integrated sedimentological and micropalaeontological benthic foraminifers and ostracods analyses of two continuous cores 40 m and 50 m long respectively recovered in the lower delta plain of modern petit rhone delta along with data from the previously studied core sf enable detailed reconstruction of the late pleistocene holocene palaeoenvironmental evolution of the rhone delta system through identification of nine microfossil assemblages and with the aid of 28 radiocarbon dates a high resolution picture of stratigraphic architecture is offered for the first time for the entire post glacial succession above late pleistocene fluvial channel gravels a retrograding pattern of swamp and estuarine bay deposits lower transgressive systems tract tst is overlain by vertically stacked late transgressive nearshore deposits upper tst this succession reflects the progressive landward migration of the palaeoshoreline driven by the rapid post glacial sea level rise which took place in the study area between ca 12 and 7 cal ky bp the following deceleration in sea level rise highstand phase induced the onset of deltaic sedimentation as evidenced by superposition of middle late holocene prodelta delta front and delta plain deposits within the cored succession at distal location the occurrence within prodelta deposits of a distinctive microfossil assemblage dominated by opportunistic benthic foraminifer valvulineria bradyana marks the onset of the rhone delta mud belt around 4 cal ky bp identification and lateral tracking of six separate flooding surfaces within the tst enable the characterization of five short term millennial to sub millennial scale depositional cycles with distinctive transgressive regressive internal architecture t r 1 5 the lower transgressive portions of cycles 1 3 11 8 9 8 cal ky bp mark abrupt shifts from freshwater to increasingly mixed brackish marine environments under conditions of rapid sea level rise in contrast the upper regressive portions represent the filling of newly formed accommodation space via extensive crevasse to bay head delta processes cycles 4 and 5 9 8 8 2 cal ky bp and the uppermost transgressive deposit below the maximum flooding surface document three distinct landward shifts of the shoreline that took place under conditions of rapidly increasing sea level rise the vertical stacking of these millennial scale cycles is interpreted to reflect the stratigraphic response to stepwise sea level rise during the early holocene the youngest flooding surface may represent the sea level signature of the 8 2 ka climate event

holocene development of the yellow river s subaqueous delta north yellow sea high resolution seismic profiles from the north yellow sea reveal a 20 40 m thick subaqueous clinoform delta that wraps around the eastern end of the shandong peninsula extending into the south yellow sea this complex sigmoidal oblique clinoform containing an estimated 400 km 3 of sediment overlies prominent relict transgressive surfaces the nearshore topset of the clinoform 50 m contain less than 1 m of holocene sediment with low sedimentation rates 1 mm year in contrast to other clinoforms the shandong clinoform appears to be a compound subaqueous deltaic system with what we interpret to be proximal and distal phases of clinoform development the underlying proximal sequence formed proximally between f11 and 9 2 ka in response to a temporary pause in the rapid postglacial sea level rise after the meltwater pulse 1b mwp 1b and increased discharge from the yellow river to the north yellow sea due to intensification of the summer monsoon a flooding surface appears to separate the proximal and distal phases corresponding to the next rapid sea level rise 9 5 9 2 ka bp mwp 1c since 9 2 ka bp an overlying distal sedimentary sequence has accumulated reflecting the backstepping and shifting river mouth westward to the gulf of bohai some inputs from coastal erosion and nearby small streams may be locally important along shore transport cross shelf advection and upwelling in the north yellow sea have reworked post lgm sediment and have helped maintain the morphology of the clinoform in the shandong mud wedge d 2004 elsevier b v all rights reserved

multiproxy assessment of holocene relative sea level changes in the western mediterranean sea level variability and improvements in the definition of the isostatic signal abstract a review of 917 relative sea level rsl data points has resulted in the first quality controlled database constraining the holocene sea level histories of the western mediterranean sea spain france italy slovenia croatia malta and tunisia we reviewed and standardized the geological rsl data points using a new multi proxy methodology based on 1 modern taxa assemblages in mediterranean lagoons and marshes 2 beachrock characteristics cement fabric and chemistry sedimentary structures and 3 the modern distribution of mediterranean fixed biological indicators these rsl data points were coupled with the large number of archaeological rsl indicators available for the western mediterranean we assessed the spatial variability of rsl histories for 22 regions and compared these with the ice 5g vm2 gia model in the western mediterranean rsl rose continuously for the whole holocene with a sudden slowdown at 7 5 ka bp and a further deceleration during the last 4 0 ka bp after which time observed rsl changes are mainly related to variability in isostatic adjustment the sole exception is southern tunisia where data show evidence of a mid holocene high stand compatible with the isostatic impacts of the melting history of the remote antarctic ice sheet our results indicate that late holocene sea level rise was significantly slower than the current one first estimates of gia contribution indicate that at least in the northwestern sector it accounts at least for the 25 30 of the ongoing sea level rise recorded by mediterranean tidal gauges such contribution is less constrained at lower latitudes due to the lower quality of the late holocene index points future applications of spatio temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of mediterranean sea level rise

from river to shelf anatomy of a high frequency depositional sequence the late pleistocene to holocene tiber depositional sequence the late pleistocene holocene tiber delta succession represents the most recent and one of the best preserved high frequency low rank depositional sequences developed along the latium continental margin of the italian peninsula several previous studies have established a robust data set from which it has been possible to describe the stratigraphic architecture of the entire tiber depositional sequence from the landward to seaward sectors and over a distance of 60 km the tiber depositional sequence shows many characteristics found in other late pleistocene to holocene deltaic and coastal successions of the mediterranean area the stratigraphic architecture of the tiber depositional sequence is controlled mainly by glacioeustasy although factors such as tectonic uplift volcanism and subsidence exert an influence at a local scale the resulting depositional model allowed discussion of some important points such as 1 the genesis of the tiber mixed bedrock alluvial valley extending from the coastal plain to the innermost portion of the shelf recording i multiple episodes of incision during relative sea level fall and ii a downstream increase of depth and width of the valley during the base level fall and the subsequent base level rise 2 the different physical expression of the tiber depositional sequence boundary from landward to seaward and its diachronous and composite character 3 the maximum depth reached by the tiber early lowstand delta at the end of the sea level fall is estimated at ca 90 m below the present sea level and not at 120 m as suggested by previous works 4 the backward position of the tiber late lowstand delta relative to the deposit of early lowstand 5 the change of the channel pattern and of the stacking pattern of fluvial deposits within the lowstand systems tract transgressive systems tract and highstand systems tract all of these features indicate that the late pleistocene holocene tiber delta succession even if deposited in a short period of time from a geological point of view represents the result of the close interaction among many autogenic and allogenic factors however global eustatic variations and sediment supply under the control of climatic changes can be considered the main factors responsible for the stratigraphic architecture of this sedimentary succession which has been heavily modified by human activity only in the last 3000 years

principles of regression and transgression the nature of the interplay between accommodation and sediment supply the rate of change of accommodation at the shoreline a and the rate of sediment supply s are the primary factors controlling regression and transgression in the geological record or retreat and advance of a coastal depositional system the generally accepted notion here referred to as the a s ratio concept stating that the migration of a shoreline is controlled principally by the magnitude of the ratio of a to s is insufficient and somewhat misleading partly owing to the problem of dimensional confusion the interplay of a and s inevitably results in autoretreat of the shoreline whereby the seaward advance of any shoreline is halted and is subsequently turned to landward retreat provided there is a continuous rise of relative sea level how effective the autoretreat process is depends for a given period of relative sea level rising upon the length of potential time period for the seaward advance of shoreline and is proportional to a 2 s and a super 1 5 s super 0 5 in two and three dimensional sediment dispersal modes respectively autoretreat becomes more effective as a increases and or s decreases a functions more critically to the effectiveness than s does the a s ratio concept is only approximately applicable when autoretreat is less effective i e with very low a and or very high s in this sense the autoretreat theory and the a s ratio concept are complementary to each other the autoretreat mechanism is expected to be substantially useful not only in fluvial deltas but also in many other depositional systems e g barrier islands whose evolution has been considered in terms of the a s ratio concept

global sea level control on local parasequence architecture from the holocene record of the po plain italy abstract holocene deposits exhibit distinct predictable and chronologically constrained facies patterns that are quite useful as appropriate modern analogs for interpreting the ancient record in this study we examined the sedimentary response of the po plain coastal system to short term millennial scale relative fluctuations of sea level through high resolution sequence stratigraphic analysis of the holocene succession meters thick parasequences form the building blocks of stratigraphic architecture above the younger dryas paleosol a prominent stratigraphic marker that demarcates the transgressive surface early holocene parasequences s 1 3 record alternating periods of rapid flooding and gradual shoaling and are stacked in a retrogradational pattern that mostly reflects stepped post glacial eustatic rise conversely middle to late holocene parasequences s 4 8 record a complex pattern of coastal progradation and delta upbuilding that took place following sea level stabilization at highstand starting at about 7 cal ky bp the prominent transgressive surface at the base of parasequence 1 correlates with the period of rapid global sea level rise at the onset of the holocene mwp 1b whereas flooding surfaces associated with parasequences 2 and 3 apparently reflect minor early holocene eustatic jumps reported in the literature changes in shoreline trajectory parasequence architecture and lithofacies distribution during the following eustatic highstand had instead an overwhelming autogenic component mostly driven by river avulsions delta lobe switching local subsidence and sediment compaction we document a 1000 year delayed response of the coastal depositional system to marine incursion farther inland from the maximum landward position of the shoreline a dramatic reduction in sediment flux due to fluvial avulsion resulted in marine inundation in back barrier position whereas coastal progradation was simultaneously taking place basinwards we demonstrate that the landward equivalents of marine flooding surfaces parasequence boundaries may be defined by brackish and freshwater fossil assemblages and traced for tens of kilometers into the non marine realm this makes millennial scale parasequences whether auto or allogenic in origin much more powerful than systems tracts for mapping detailed extents and volumes of sediment bodies the holocene parasequences of the po coastal plain with strong age control and a detailed understanding of sea level variation may provide insight into the driving mechanisms and predictability of successions characterized by similar depositional styles but with poor age constraint resulting in more robust interpretations of the ancient record

quantitative evidence that compaction of holocene sediments drives the present land subsidence of the po delta italy 1 deltas are highly dynamic coastal systems that over the last few decades have generally experienced a substantial area loss caused by trapping of river sediments in upland drainage basins as well as land subsidence due to natural and anthropogenic causes a major example is the po delta in the mediterranean in northeastern italy this area has experienced as much as 3 m of land subsidence from the 1930s to the 1970s primarily because of the extraction of gas bearing waters however present subsidence rates are largely unknown and the ground settlement is supposedly controlled by natural long term deep processes we have combined radar interferometric point target analysis ipta with previous geomorphological investigations on aerial satellite images and seismic surveys and geochronological data from core samples and geomechanical in situ tests to assess the current sinking of the delta and to understand the processes controlling the vertical movement the high density of the measurable point targets more than 15 000 allows characterization of the spatial variation in the vertical land motions vlm ranging from 1 to 15 mm yr we find that subsidence rates are significantly correlated with the age of highly compressible holocene deposits that compose the shallowest 30 40 m of the sedimentary sequence a typical log type consolidation equation applicable at the scale of the entire delta has been obtained we conclude that the consolidation of late holocene sediments is the major cause of the present land subsidence in the po river delta this finding has significant impact on the understanding of many other modern deltas that were formed in the lower holocene epoch

sedimentary response to late quaternary sea level changes in the romagna coastal plain northern italy data from 17 continuously cored boreholes 40 170 m deep reveal the subsurface stratigraphy of the romagna coastal plain sedimentological and microfaunal data allow the distinction of eight facies associations of late pleistocene holocene age including 18 lithofacies and 16 faunal associations ten 14c dates provide the basis to establish a sequence stratigraphic framework for the succession corresponding to the upper part 35 ky bp of the last glacio eustatic cycle the eight facies associations can be grouped into lowstand transgressive and highstand systems tracts the upper part of the lowstand systems tract consists of alluvial plain deposits these accumulated during the late pleistocene when the shoreline was 250 km south of its present day position a pronounced stratigraphic hiatus between 25 and 8 8 ky bp is invariably recorded at the upper boundary transgressive surface of these pleistocene indurated and locally pedogenized alluvial deposits the succeeding postglacial history is represented by a well developed transgressive regressive cycle transgressive deposits interpreted to reflect the rapid landward migration of a barrier lagoon system include two wedge shaped paralic and marine units these thicken in opposite directions and are separated by a ravinement surface above the transgressive deposits the maximum flooding surface mfs marks the change from a transgressive barrier lagoon complex to a prograding wave dominated delta system early po delta the mfs can be traced landwards where it constitutes the base of lagoonal deposits an aggradational to progradational stacking pattern of upper delta plain marsh lower delta plain lagoon bay and delta front beach ridge deposits reflects the progressive increase in the sediment supply accommodation ratio during the following highstand the alluvial deposits capping the sequence accumulated by the 13th century ad in response to an avulsion event that caused abandonment of the former po delta lobe and the northward migration of the po river towards its present position

from static to dynamic provenance analysis sedimentary petrology upgraded abstract the classical approach to sandstone petrology established in the golden years of plate tectonics and based on the axiom that detrital modes of sandstone suites primarily reflect the different tectonic settings of provenance terranes has represented a benchmark for decades the composition of sand and sandstone however simply provides us with a distorted image of the lithological structure of source terranes and gives us little clue whether they are allochthonous or autochthonous orogenic or anorogenic young or old what we may able to see reflected in detrital modes is the nature of source terranes continental arc oceanic and the tectonostratigraphic level reached by erosion in space and time the proposed new approach to the petrology of sand and sandstone 1 starts with a simple classification scheme circulated since the 1960s which is purely descriptive objective and free of ill defined ambiguous terms and 2 focuses on the nature and tectonostratigraphic level of source terranes further steps are essential to upgrade provenance analysis acquiring knowledge from modern settings is needed to properly identify and wherever possible correct for physical and chemical processes introducing environmental and diagenetic bias and thus address nature s complexities with adequate conceptual tools equally important is the integration of multiple techniques ideally including bulk sediment multi mineral and single mineral methods bulk sediment petrography remains the fundamental approach that allows us to capture the most precious source of direct provenance information represented by the mineralogy and texture of rock fragments bulk sediment geochemistry applicable also to silt and clay carried in suspension is a superior method to check for hydraulic sorting chemical weathering and fertility of detrital minerals in different sediment sources detrital geochronology thermochronology and isotope geochemistry reveal the diverse time structures of source rocks and have become necessary complementary techniques in modern provenance analysis inferences on geodynamic processes need independent geological information and come last but if tackled properly they can lead us much farther than the standard label obtained by using triangular diagrams uncritically as if they were infallible oracles

mud re distribution in epicontinental basins exploring likely processes abstract fine grained clastic sediments are very common in the interior deposits of ancient epicontinental seas not only do they make up the gross lithology in these basins but they can also be traced for more than 1000 km offshore from basin margins given that epicontinental seas were overall shallow and in many parts most likely less than 100 m deep basin floor slopes can safely be expected to be in the 0 01 to 0 001 range for much of depositional history known processes that bring muds to the basin margin and beyond are hypopycnal river plumes hyperpycnal fluvial discharge events storm setup relaxation flows and gravity driven fluidized muds with the exception of river plumes all of these processes require the presence of sufficient slope for sustained movement due to that constraint these processes combined might in the majority of situations have been able to move muddy sediments on the order of 100 km offshore whereas this is sufficient to distribute mud across marginal shelf seas it becomes problematic in the case of much larger epicontinental seas for example those of upper devonian or upper cretaceous times extended in places for thousands of kilometers and thus a process is needed that can move muddy sediments the rest of the way flume studies of the bedload transport of mud combined with observations from the rock record suggest that wind or tide induced bottom current circulation was most likely essential for moving muddy sediments from the periphery of epicontiental seas to their interiors remobilization of seafloor muds during frequently recurring lowering of sea level is likely to have aided in this process

why was the indian ocean dipole weak in the context of the extreme el nino in 2015 abstractthe indian ocean witnessed a weak positive indian ocean dipole iod event from the boreal summer to autumn in 2015 while an extreme el nino occurred over the tropical pacific this was different from the case in 1997 98 when an extreme el nino and the strongest iod took place simultaneously the analysis here suggests that the unique sea surface temperature anomaly ssta pattern of el nino in 2015 might have contributed to the weak iod that year el nino in 2015 had a complex ssta pattern with positive warming over the central and eastern tropical pacific such a combination of the classic el nino also known as cold tongue el nino and the recently identified central pacific el nino also known as el nino modoki ii had opposite remote influences on the tropical indian ocean the classic el nino reduced the strength of the walker circulation over the tropical indian ocean but this was offset by el nino modoki ii this study points out that the iod can be strongly modulated by combined el ni

indian ocean dipolelike variability in the csiro mark 3 coupled climate model abstract coupled ocean atmosphere variability in the tropical indian ocean is explored with a multicentury integration of the commonwealth scientific and industrial research organisation csiro mark 3 climate model which runs without flux adjustment despite the presence of some common deficiencies in this type of coupled model zonal dipolelike variability is produced during july through november the dominant mode of variability of sea surface temperature resembles the observed zonal dipole and has out of phase rainfall variations across the indian ocean basin which are as large as those associated with the model el nino southern oscillation enso in the positive dipole phase cold sst anomaly and suppressed rainfall south of the equator on the sumatra java coast drives an anticyclonic circulation anomaly that is consistent with the steady response gill model to a heat sink displaced south of the equator the northwest southeast tilting sumatra java coast results in cold sea surface temperature

sand composition and sedimentary evolution of a late quaternary depositional sequence northwestern adriatic coast italy abstract in order to detect temporal and spatial variations in detrital supply in the upper part of the last depositional sequence of late pleistocene holocene age we conducted a combined petrographic and stratigraphic study in the romagna coastal plain south of the po delta northern italy we analyzed heavy minerals and the bulk composition of sands from cores and surface samples by using petrographic and stratigraphic data on composition of modern beach and major river deposits new aspects of detrital dispersal mechanisms and the depositional history of the study area are documented the heavy mineral distribution coupled with the dolostone and volcanic rock fragment contents of bulk sands allow identification of three different petrofacies petrofacies a petrofacies b and petrofacies c which have been interpreted as of apenninic mixed eastern alps po river basin and po river catchment basin provenance respectively distribution of the three petrofacies changed through time in response to landward and seaward shifting of the coastline during the late pleistocene lowstand a pure apenninic provenance characterized the romagna coastal plain petrofacies a during the holocene transgression when the shoreline migrated tens of kilometers west of its present position eastern alpine sediment sources fed littoral facies petrofacies b probably as a result of southward transport by littoral drift this sediment supply continued during the early regressive phases and was cut off by a change in coastal morphology related to the development of the early po delta this led to the establishment of a sediment supply entirely related to the po river catchment basin petrofacies c changes in the compositional signature of sand in the youngest beach ridges mark the abandonment of the early po delta due to an avulsion event and testify to the establishment of a coastal system fed by rivers draining the apennines petrofacies a we emphasize sand petrography as an important tool in studying the internal architecture of sandy clastic depositional units on detailed spatial scales and its use in deciphering the depositional history of complex sedimentary successions fig 1 location of the study area end page 829

the vaca muerta quintuco system tithonian valanginian in the neuquen basin argentina a view from the outcrops in the chos malal fold and thrust belt the vaca muerta quintuco system uppermost lower tithonian lower valanginian is a thick shallowing upward sedimentary cycle consisting of dark bituminous shales marlstones limestones and sandstones cropping out in the neuquen basin west central argentina this paper analyzes three outcrop sections in chos malal area northem neuquen province detailed facies analysis allows us to differentiate six facies associations representing basinal to proximal outer ramp facies of a homoclinal carbonate ramp system vaca muerta formation and basinal to shoreface facies of a mixed carbonate siliciclastic shelf system quintuco formation prograding westward from the eastern margin of the basin two sequence hierarchies were recognized 5 composite depositional sequences third order and 15 high frequency sequences fourth order fluctuations in organic matter content within the vaca muerta formation suggest a relationship with depositional sequences finding the highest values associated with transgressive systems tract whereas the transition to the quintuco formation shows a strong decrease in total organic carbon the x ray diffraction studies show an increase of clay minerals and quartz in the transgressive systems tract of the vaca muerta formation and an increase in the content of calcite in highstand systems tracts this pattern is reversed in the quintuco formation our sequence stratigraphic approach contributes to the understanding of the relationship between organic matter clay minerals facies stacking pattern and relative sea level changes in this exceptional shale oil and shale gas unconventional reservoir this study may be helpful for a better postulate of petrophysical and geomechanical models for unconventional exploration

a depositional model for offshore deposits of the lower blue gate member mancos shale uinta basin utah usa depositional models that use heterogeneity in mud dominated successions to distinguish and diagnose environments within the offshore realm are still in their infancy despite significant recent advances in understanding the complex and dynamic processes of mud deposition six cored intervals of the main body of the mancos shale the lower blue gate member uinta basin were examined sedimentologically stratigraphically and geochemically in order to evaluate facies heterogeneity and depositional mechanisms unique sedimentological and geochemical features are used to identify three offshore environments of deposition the prodelta the mudbelt and the sediment starved shelf prodelta deposits consist of interlaminated siltstone and sandstone and exhibit variable and stressed trace fossil assemblages and indicators of high sedimentation rates the prodelta was dominated by river fed hyperpycnal flow mudbelt deposits consist of interlaminated siltstone and sandstone and are characterized by higher bioturbation indices and more diverse trace fossil assemblages ripples scours truncations and normally graded laminations are abundant in prodelta and mudbelt deposits indicating dynamic current conditions mudbelt sediment dispersal was achieved by both combined flow above storm wave base and current enhanced and wave enhanced sediment gravity flows below storm wave base sediment starved shelf deposits are dominantly siltstone to claystone with the highest calcite and organic content bioturbation is limited to absent sediment starved shelf deposits were the result of a combination of shelfal currents and hypopycnal settling of sediment despite representing the smallest volume sediment starved shelf deposits are the most prospective for shale hydrocarbon resource development due to elevated organic and carbonate content sediment starved shelf deposits are found in either retrogradational to aggradational parasequence sets or early distal aggradational to progradational parasequence sets bounding the maximum flooding surface an improved framework classification of offshore mudstone depositional processes based on diagnostic sedimentary criteria advances our predictive ability in complex and dynamic mud dominated environments and informs resource prospectivity

millennial scale depositional cycles from the holocene of the po plain italy the holocene depositional history of southeastern po plain on time scales of 103 yr is reconstructed based upon integrated sedimentological and micropalaeontological analyses of nine continuously cored boreholes about 40 m deep major palaeoenvironmental changes include the rapid landward migration of a barrier estuary lagoon system during the early middle holocene transgressive systems tract tst followed by extensive delta progradation in the last 6000 yr highstand systems tract hst detailed facies analysis of cores combined with the identification of 12 microfossils benthic foraminifer and ostracod associations allow an ultra high resolution sequence stratigraphic framework to be reconstructed particularly eight small scale high frequency cycles about 3 5 m thick and spanning intervals of time of about 1000 yr can be physically traced throughout the study area interpretation of these cycles which are invariably bounded by sharp flooding surfaces and generally show internal shallowing upward trends parasequences indicates that relative sea level changes during the holocene were episodic and punctuated by rapid phases of sea level rise followed by periods of stillstand or decreasing sea level rise from seaward to landward locations parasequence boundaries document beach barrier migration bay head delta abandonment and increasing accommodation in the coastal plain the ensuing phases of sea level stillstands resulted in the progressive filling of the newly formed accommodation space through beach progradation extensive mud deposition in behind barrier lagoonal estuarine and marsh deposits and aggradation in bay head delta systems at the head of estuaries eustacy appears to be the major controlling factor of the retrogradational stacking pattern of parasequences within the tst by contrast a complex interplay of eustacy sediment supply and subsidence with an increasing influence of autocyclic mechanisms such as channel avulsion and delta lobe abandonment controlled facies architecture within the hst the maximum flooding surface cannot be assumed to be synchronous its timing being strongly dependent upon local variations in sediment influx and subsidence this study shows that the micropalaeontologic characterization of mud prone coastal plain and estuarine successions in terms of water depth and salinity can lead to very accurate sequence stratigraphic interpretations allowing identification of parasequence boundaries that may not be detected by conventional stratigraphic approach

structure and origin of holocene cold events abstract the present interglacial the holocene spans the period of the last 11 700 years it has sustained the growth and development of modern society the millennial scale decreasing solar insolation in the northern hemisphere summer lead to northern hemisphere cooling a southern shift of the intertropical convergence zone itcz and a weakening of the northern hemisphere summer monsoon systems on the multidecadal to multicentury scale periods of more stable and warmer climate were interrupted by several cold relapses at least in the northern hemisphere extra tropical area based on carefully selected 10 000 year long time series of temperature and humidity precipitation as well as reconstructions of glacier advances the spatiotemporal pattern of six cold relapses during the last 10 000 years was analysed and presented in form of a holocene climate atlas hoclat see http www oeschger unibe ch research projects holocene atlas a clear cyclicity was not found and the spatiotemporal variability of temperature and humidity precipitation during the six specific cold events 8200 6300 4700 2700 1550 and 550 years bp was very high different dynamical processes such as meltwater flux into the north atlantic low solar activity explosive volcanic eruptions and fluctuations of the thermohaline circulation likely played a major role in addition internal dynamics in the north atlantic and pacific area including their complex interaction were likely involved

late quaternary multiple incised valley systems an unusually well preserved stratigraphic record of two interglacial valley fill successions from the arno plain northern tuscany italy

storage thresholds for relative sea level signals in the stratigraphic record the tug of relative sea level rsl set by climate and tectonics is widely viewed as the most important boundary condition for the evolution of deltas however the range of amplitudes and periodicities of rsl cycles stored in deltaic stratigraphy remains unknown experimental results presented here suggest that extraction of rsl cycles from the physical stratigraphic record requires their magnitudes and periodicities to be greater than the spatial and temporal scales of the internal autogenic dynamics of deltas these results predict stratigraphic storage of information pertaining to rsl cycles during icehouse earth conditions however these thresholds commonly overlap with the magnitudes and periodicities of rsl cycles for major river deltas during greenhouse earth conditions suggesting stratigraphic signal shredding this theory suggests quantitative limits on the range of paleo rsl information that can be extracted from stratigraphy which could aid the prediction of deltaic response to climate change

onshore to offshore anatomy of a late quaternary source to sink system po plain adriatic sea italy abstract in understanding the evolution of siliciclastic systems late quaternary analogs may enable reliable predictive models of facies tract architecture the po plain adriatic sea system where a wealth of research has been conducted during the last 20 years represents one of the most intensively investigated late quaternary successions with the aid of a chronologically well constrained stratigraphy paleoenvironmental evolution is tracked for the first time from fluvial to deep marine realms over 1000 km in length vertical stacking trends onshore and stratal terminations offshore are the key observations that allow identification of surfaces with sequence stratigraphic significance systems tract boundaries in the distinct segments of the system recurring motifs in stratigraphic architecture showing tight coupling of sedimentary responses among source area catchment basin and coastal and marine depocenters reveal a cyclicity driven by glacio eustatic fluctuations in the milankovitch band due to high rates of subsidence middle pleistocene forced regressive systems tracts are exceptionally expanded and the mis5e mis2 interval late pleistocene preserves a nearly continuous record of fourth order 100 kyr stepwise sea level fall the stratigraphic architecture of last glacial maximum deposits highlights the genetic relations between channel belt development pedogenesis and sediment delivery to the lowstand delta through narrow incised valley conduits the late glacial holocene succession records the last episode of sea level rise and stabilization through well developed patterns of shoreline transgression regression tst hst that can be readily traced updip from offshore to onshore locations architectural styles across the whole system reflect a dominance of allogenic forcing in the tst as opposed to a predominantly autogenic control on stratigraphic development in the hst external drivers of facies architecture were also effective on millennial timescales the younger dryas cold reversal which marks the transgressive surface on land records a short lived episode of subaqueous progradation that is correlative onshore with widespread immature paleosol development and small sized channel belt formation quantitative assessment of sediment budgets over different time intervals requires precise positioning of the key bounding surfaces based on this approach we outline for the first time over the entire po adriatic basin an estimate of the sediment volumes stored in each systems tract

the alps with little ice evidence for eight holocene phases of reduced glacier extent in the central swiss alps glacially deformed pieces of wood organic lake sediments and clasts of reworked peat have been collected in front of alpine glaciers since ad 1990 the palaeoglaciological interpretation of these organic materials is related to earlier phases of glacier recession surpassing that of today s shrunken glaciers and to tree growth and peat accumulation in the valleys now occupied by the glaciers glacial transport of the material is indicated by wood anatomy incorporated silt sand and gravel particles missing bark and deformed treerings a total of 65 samples have been radiocarbon dated so far and clusters of dates provide evidence of eight phases of glacier recession 9910 9550 9010 7980 7250 6500 6170 5950 5290 3870 3640 3360 2740 2620 and 1530 1170 calibrated years bp allowing for the timelag between climatic fluctuations glacier response and vegetation colonization these recession phases may lag behind climatic changes by 100 200 years

a source to sink compositional model of a present highstand an example in the low rank tiber depositional sequence latium tyrrhenian margin italy abstract our source to sink compositional model of sediment distribution in the present highstand of the tiber depositional sequence has important implications for sediment source lithology generation transport and deposition in the tiber river system sand compositional trends reflect provenance mixing anthropic intervention and the effects of local autogenic factors in continental to marine depositional environments fluvial feldspatho quartzo lithic sand results from the contribution of the major tributaries of the tiber drainage basin which can be divided into two sub basins separated by the corbara dam built in the 1950s upstream drainage basin sand has a siliciclastic sedimentary lithic signature whereas carbonate and volcanic lithic fragments dominate downstream drainage basin sand downstream sand is further modified in the coastal environment by hydraulic sorting and mixed with detritus derived from the recycling of coastal dune sand and altered volcaniclastic paleosols the latter are associated with lower course floodplain and channel deposits which produce a quartzo feldspatho lithic sand sediment grain size zonation in the marine environment is influenced by coastal hydrodynamics which in turn produce two detrital populations with distinct compositional signatures and hydraulic behavior coarser minerals essentially pyroxene phenocrysts and finer feldspar grains are progressively concentrated in higher energy and lower energy environments respectively biogenic continental shelf and slope deposits off the tiber river mouth show very little riverine influence this study of the last highstand system tract in the tiber depositional sequence clarifies the effects of hydraulic sorting grain size dependence and sediment reworking in controlling the final composition of modern sand this knowledge can be used to better understand detrital modes of ancient sedimentary successions

sequence stratigraphy and the resolution of the fossil record sequence stratigraphy a major theoretical achievement of earth sciences integrates facies associations and stratal architecture within a chronological framework of the geological record the sequence stratigraphic model implies that sediment supply to the basin preservation potential of individual horizons and the resolution of paleontological data co vary with base level fluctuations especially for siliciclastic depositional systems using holocene transgressive regressive successions of the po plain italy we assessed the model s hypotheses by analyzing 249 marine mollusk shells dated individually using 14 c calibrated amino acid racemization methods as postulated by the model the temporal resolution of the fossil record frequency of depositional events and net accumulation rates decreased upward concomitantly through the transgressive systems tract reaching minima in the condensed section maximum flooding zone the reverse trend with increasingly frequent thicker and less time averaged beds was observed throughout the overlying highstand systems tract the results quantify the postulated sequence stratigraphic asymmetry in temporal resolution of the fossil and sedimentary records

linking holocene vegetation dynamics palaeoclimate variability and depositional patterns in coastal successions insights from the po delta plain of northern italy abstract mediterranean deltaic coastal plains represent relatively underexplored depositional archives that record the holocene response of vegetation and depositional systems to high frequency climate changes in this study we examine a 25 m thick succession of holocene age core em2 recovered in the innermost portion of the po delta plain of northern italy applying an integrated palyno stratigraphic approach the existence of a paludal freshwater setting inland of the line of maximum marine transgression favoured a low degree of pollen transportation application of cluster analysis to this palynological record leads to the identification of pollen derived biomes and seven auto ecological groups of taxa that discriminate environmental signal depositional facies and regional climate conditions within a well dated coastal record percentage variations of hygrophytes aquatics and pasture meadow herbs reveal local environmental dynamics enabling the detailed facies characterisation of the cored succession especially in terms of water table conditions framed into a chronologically constrained high resolution facies context the proportion of montane taxa climate degradation indicator relative to mediterranean taxa and quercus other deciduous trees climate optimum indicators highlight a vegetation climate variability in the plain that fits with bond events especially for the early mid holocene i e preboreal and boreal oscillation 8 2 ka event supporting a strong mediterranean north atlantic climate connection for the first time pollen from a continental succession of the adriatic area clearly depicts the effects of the 8 2 ka cooling event on vegetation patterns progressive degradation in high altitude communities and depositional dynamics increased fluvial activity assessing the major role played by climate changes in shaping coastal landscapes in addition to glacio eustatic variations

the role of foraminifera as indicators of the late pleistocene holocene palaeoclimatic fluctuations on the deltaic environment the example of tiber delta succession tyrrhenian margin italy abstract the palaeoclimatic and palaeoenvironmental reconstruction of the last 39 0 kyr of the central tyrrhenian shelf are presented in this paper micropalaeontological sedimentological and stable isotopic data integrated by radiocarbon dates were determined from three cores drilled in the tiber delta sequence tds which constitutes one of the most complete late quaternary high frequency depositional sequences in the mediterranean area short period climate variations that induced short period events caused changes in the tiber run off and increased the sediment supply and grain size in the delta system the three cores with different thicknesses record all the system tracts forming the tds three intervals corresponding to the early and late lowstand transgressive and highstand system tracts tst and hst were recognised the first is characterised by shoreface inner shelf deposits and corresponds to a general cooling period characterised by short warmer periods approximately 1 0 kyr confirming the climatic variability of mis 3 mis 2 a very condensed deposition affected the second interval which is characterised by a very low sedimentation rate corresponding to the tst of tds the third interval corresponding to holocene shelf deposits shows small climatic oscillations that mark an enhanced seasonality typical of the modern tyrrhenian regime at the millennial scale two warm intervals copper age and late bronze age ii century ac alternating with two cold humid intervals bond cycle b3 rcc 4 2 3 8 kyr bp of mayewski events and the little ice age have been recognised

the transition from wave dominated estuary to wave dominated delta the late quaternary stratigraphic architecture of tiber river deltaic succession italy abstract this paper presents a detailed description of the stratigraphic architecture of the late pleistocene holocene tiber delta succession in order to document the passage from wave dominated estuary to wave dominated delta in the broader context of late quaternary sea level fluctuations this succession constitutes a sequence stratigraphic unit known as tiber depositional sequence tds which was deposited during the last glacial interglacial cycle last 120 ka our study is based on the examination of an enormous amount of data derived from the stratigraphy of about 300 wells petrographical and paleontological data foraminifera ostracoda pollen and plant macrofossils 14 c dating and from the integration of geomorphological and geoarcheological data recently a 100 m deep core pesce luna well was studied through a multidisciplinary approach and a detailed description of sedimentary facies foraminifer and ostracod assemblages pollen and 14 c dating is presented in this paper the new data allowed to produce three new correlation panels and to describe in more detail with respect to previous interpretations the stratigraphic depositional architecture of the tds which internally shows the preservation of sediment deposited during the early and late lowstand the transgressive and the highstand systems tracts alluvial and coastal depositional systems characterize the early lowstand phase of the tds which developed during the eustatic sea level fall between about 120 and 30 26 yr bp during the late lowstand phase which is characterized by stillstand and slow eustatic sea level rise a prograding delta and an aggrading incised valley fluvial fill developed the tiber incised valley was transformed into a wave dominated estuary during the transgressive phase tst whereas a coastal shelf sedimentation took place during the subsequent highstand phase hst this study confirms the lithofacies distribution resulting from transgression and infilling of the wave dominated estuaries but also shows how the transition to a wave dominated delta prograding at the time of sea level highstand occurred changes in sediment input climatic variations and more recently human activities played a major role in the development of the tiber delta during the last 20 000 yr bp in the last 3000 years a relationship between progradational phases of the delta and flood events of the tiber river has been highlighted suggesting also the formation and merging of barrier spits to the mainland

muddy prodeltaic hyperpycnites in the lower genesee group of central new york usa implications for mud transport in epicontinental seas abstract recent studies of marine continental shelves show that hyperpycnal flows are responsible for offshore transport of large volumes of sediment detailed facies analysis and petrography of the lower genesee group in the northern appalachian basin nab shows a wealth of sedimentary textures and fabrics that indicate mud deposition by lateral transport across and along the shelf under energetic conditions intervals of silt rich mudstones and muddy siltstones with internal scours diffuse stratification soft sediment deformation normal and inverse lamina set grading and a reduced intensity and diversity of bioturbation occur in multiple facies types and interrupt what appears to be the overall background sedimentation these intervals and their sedimentary features are interpreted as products of high density fluvial discharge events which generated turbulent flows that carried fine grained clastics several tens of kilometers offshore from the paleoshoreline recognizing these sediments as products of river flood and storm wave generated offshore directed underflows challenges previous depositional models for organic rich mudstones in the lower genesee succession which call for clastic starvation and suspension settling of clay and silt in a deep stratified basin rapid deposition of fine grained intervals from hyperpycnal plumes in a setting favoring preservation of organic rich mudstones calls for a reappraisal of the depositional setting of not only the genesee group but also of comparable mudstone successions in the appalachian basin and elsewhere

el nino modoki and its possible teleconnection 1 using observed data sets mainly for the period 1979 2005 we find that anomalous warming events different from conventional el nino events occur in the central equatorial pacific this unique warming in the central equatorial pacific associated with a horseshoe pattern is flanked by a colder sea surface temperature anomaly ssta on both sides along the equator empirical orthogonal function eof analysis of monthly tropical pacific ssta shows that these events are represented by the second mode that explains 12 of the variance since a majority of such events are not part of el nino evolution the phenomenon is named as el nino modoki pseudo el nino modoki is a classical japanese word which means a similar but different thing the el nino modoki involves ocean atmosphere coupled processes which include a unique tripolar sea level pressure pattern during the evolution analogous to the southern oscillation in the case of el nino hence the total entity is named as el nino southern oscillation enso modoki the enso modoki events significantly influence the temperature and precipitation over many parts of the globe depending on the season the impacts over regions such as the far east including japan new zealand western coast of united states etc are opposite to those of the conventional enso the difference maps between the two periods of 1979 2004 and 1958 1978 for various oceanic atmospheric variables suggest that the recent weakening of equatorial easterlies related to weakened zonal sea surface temperature gradient led to more flattening of the thermocline this appears to be a cause of more frequent and persistent occurrence of the enso modoki event during recent decades

paleoenvironmental reconstruction of late quaternary succession by foraminiferal assemblages of three cores from the san benedetto del tronto coast central adriatic sea italy new shelf records based on benthic foraminiferal assemblages allowed reconstruction of the paleoenvironmental evolution of the central adriatic sea during the late quaternary four distinct assemblages related to four different environments were identified based on multivariate analyses cluster analysis and principal component analysis circalittoral shallow water with vegetation deltaic and shallow marine with riverine influence two main phases were recognized by comparing the study area with the northern and southern portion of the adriatic basin the first phase was characterized by the last glacial lowstand or the beginning of the last pleistocene transgression the foraminiferal assemblage distribution was controlled by sea level changes and by the location of the ancient po river delta likely placed at the northern margin of the mid adriatic deep a subsequent deepening from a deltaic to normal marine shallow water environment occurred river supply decreases consistently from the bottom to the top of the cores due to the northern migration of the po delta the second phase which occurred during the holocene was characterized by sea level stabilization and modern water circulation pattern circalittoral foraminiferal assemblage typical of the outer mud belt developed during this second phase

quantitative bathymetric models for late quaternary transgressive regressive cycles of the po plain italy abstractin marine settings quantitative bathymetric models can be developed using various water depth proxies including epibiont distribution sedimentologic features and the distribution of benthic taxa in time and space here the late quaternary bathymetric history of the po coastal plain italy has been reconstructed using mollusk samples from a network of 16 cores multiple analytical approaches have been applied in a comparative fashion a direct ordination approach was used to estimate sample bathymetry using weighted averaging of genera with known preferred depth weighted averaging carries an advantage of analytical simplicity and produces direct ordination models expressed in environmentally meaningful units indirect ordination methods based on depth estimates developed using posteriori calibrated ordination strategies correspondence and detrended correspondence analysis calibrated against present day bathymetric data yielded results consistent with weighted averaging regardless of the

holocene flood frequency across the central alps solar forcing and evidence for variations in north atlantic atmospheric circulation the frequency of large scale heavy precipitation events in the european alps is expected to undergo substantial changes with current climate change hence knowledge about the past natural variability of floods caused by heavy precipitation constitutes important input for climate projections we present a comprehensive holocene 10 000 years reconstruction of the flood frequency in the central european alps combining 15 lacustrine sediment records these records provide an extensive catalog of flood deposits which were generated by flood induced underflows delivering terrestrial material to the lake floors the multi archive approach allows suppressing local weather patterns such as thunderstorms from the obtained climate signal we reconstructed mainly late spring to fall events since ice cover and precipitation in form of snow in winter at high altitude study sites do inhibit the generation of flood layers we found that flood frequency was higher during cool periods coinciding with lows in solar activity in addition flood occurrence shows periodicities that are also observed in reconstructions of solar activity from 14 c and 10 be records 2500 3000 900 1200 as well as of about 710 500 350 208 suess cycle 150 104 and 87 gleissberg cycle years as atmospheric mechanism we propose an expansion shrinking of the hadley cell with increasing decreasing air temperature causing dry wet conditions in central europe during phases of high low solar activity furthermore differences between the flood patterns from the northern alps and the southern alps indicate changes in north atlantic circulation enhanced flood occurrence in the south compared to the north suggests a pronounced southward position of the westerlies and or blocking over the northern north atlantic hence resembling a negative nao state most distinct from 4 2 to 2 4 kyr bp and during the little ice age south alpine flood activity therefore provides a qualitative record of variations in a paleo nao pattern during the holocene additionally increased south alpine flood activity contrasts to low precipitation in tropical central america cariaco basin on the holocene and centennial time scale this observation is consistent with a holocene southward migration of the atlantic circulation system and hence of the itcz driven by decreasing summer insolation in the northern hemisphere as well as with shorter term fluctuations probably driven by solar activity

classifying el nino modoki i and ii by different impacts on rainfall in southern china and typhoon tracks based on their opposite influences on rainfall in southern china during boreal fall this paper classifies el nino modoki into two groups el nino modoki i and ii which show different origins and patterns of sst anomalies the warm sst anomalies originate in the equatorial central pacific and subtropical northeastern pacific for el nino modoki i and ii respectively thus el nino modoki i shows a symmetric sst anomaly distribution about the equator with the maximum warming in the equatorial central pacific whereas el nino modokiii displays an asymmetric distribution with the warmsstanomaliesextending fromthe northeastern pacifictotheequatorialcentralpacific additionally thewarmsstanomaliesintheequatorialcentralpacific extend farther westward for el nino modoki ii than for el nino modoki i similar to the canonical el nino el nino modoki i is associated with an anomalous anticyclone in the philippine sea that induces south westerly wind anomalies along the south coast of china and carries the moisture for increasing rainfall in southern china for el nino modoki ii an anomalous cyclone resides east of the philippines associated with northerly wind anomalies and a decrease in rainfall in southern china the canonical el nino and el nino modoki i are associated with a westward extension of the western north pacific subtropical high wnpsh whereas el nino modoki ii shifts the wnpsh eastward differing from canonical el nino and el nino modoki i el nino modoki ii corresponds to northwesterly anomalies of the typhoon steeringflow which are unfavorable for typhoons to make landfall in china

the modern po delta system lobe switching and asymmetric prodelta growth the modern po delta system comprising five main delta lobes has been investigated by integrating vhr seismic surveys recorded offshore from water depths as shallow as 5 m to the toe of the prodelta in about 30 m with accurate historical cartography extending back several centuries previous studies give sedimentological and geochronological information from precisely positioned sediment cores this combined historical and stratigraphic reconstruction of the modern po prodelta allows volumetric reconstructions indicating an average sediment load of 9 4 10 6 ty r 1 for po di pila and po di goro gnocca lobes this estimate is remarkably consistent with the total sediment load of 11 5 10 6 ty r 1 available for parts of the last century from a gauge station at the apex of the delta plain in pontelagoscuro these integrated stratigraphic studies allow to explain the key characters of the po delta system a the marked asymmetry of the whole delta prodelta system reflecting prevailing sediment dispersal to the south of each individual delta outlet b the shoreparallel overlapping of successive prodelta lobes fed by distinct river outlets of ever changing relative importance c the delta outlets being artificially forced in a fixed position so that natural avulsion is prevented and delta lobes undergo headland retreat leaving a marked erosion on the prodelta d the presence of prodelta lobes showing widespread bcut and fillq features ranging from 100 to 300 m and depths up to 4 5 m filled with massive silt to very fine sand offshore of short lived very active distributary channels e g po di tolle lobe and suggesting that in some particular interval short lived episodes of submarine erosion are induced by catastrophic increases in river discharge of natural origin or induced by human maintenance the seismic stratigraphy of the modern po delta documents that markedly distinct prodelta architectures form when a newly activated lobe is located updrift north in this case or downdrift south of the one that is retreating in the first case the abandoned lobe becomes sheltered by the new rapidly advancing one in the opposite case the retreating lobe is updrift and a substantial portion of the sediment is cannibalized and transported to the new lobe downdrift d 2005 elsevier b v all rights reserved

systematic vertical and lateral changes in quality and time resolution of the macrofossil record insights from holocene transgressive deposits po coastal plain italy abstract in siliciclastic marine settings skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into biological and sequence stratigraphic processes to investigate taphonomic signatures of transgressive intervals we analysed three cores along a depositional profile from the high resolution chrono and stratigraphic framework of the holocene po coastal plain in northern italy coupled multivariate taphonomic and bathymetric trends delineated spatial and temporal gradients in sediment starvation bypassing suggesting that quality and resolution of the fossil record vary predictably along the studied depositional profile moreover integration of taphonomic bathymetric and fossil density trends across the study area reveals distinctive signatures useful in characterizing facies associations and determining surfaces and intervals of sequence stratigraphic significance within the southern po plain succession taphonomic degradation of macroskeletal remains increases from proximal nearshore to distal offshore locations this trend is discernible for both biologically driven bioerosion and physically driven e g dissolution abrasion shell alterations compared to the up dip most proximal core the down dip core is distinguished by shell rich lithosomes affected by ecological condensation co occurrence of environmentally non overlapping taxa and by higher taphonomic alteration the onshore offshore taphonomic trend likely reflects variation in sediment accumulation along the depositional profile of the holocene northern adriatic shelf with surface near surface residence time of macroskeletal remains increasing down dip due to lower accumulation rates these results indicate that during transgressive phases changes in sea level base level are likely to produce down dip taphonomic gradients across shelves where the quality and resolution of the fossil record both deteriorate distally radiocarbon calibrated amino acid racemisation dates on individual bivalve specimens and the chronostratigraphic framework for this profile suggest jointly that the high levels of taphonomic degradation observed distally developed over millennial time scales 8ky whereas in proximal setting overall low taphonomic degradation and geochronologic constrains point to centennial scale time averaging during the late transgression phase patterns documented in the holocene transgressive and lowermost regressive deposits of the southern po plain may be characteristic of siliciclastic dominated depositional systems that experience high frequency base level fluctuations

wave enhanced sediment gravity flows and mud dispersal across continental shelves reappraising sediment transport processes operating in ancient mudstone successions recent studies of marine shelf sediment dispersal show that wave enhanced sediment gravity flows are widespread phenomena and can transport large volumes of fluid mud rapidly across low gradient shelves flow evolution is controlled by sediment supply seabed gradient and spatial distribution of wave energy at the seabed using existing flow models we predict that such flows in mud dominated sediments will develop a three part microstratigraphy produced by changing flow conditions beginning with wave induced turbulent resuspension then development of a wave enhanced sediment gravity flow prior to lutocline collapse and suspension settling petrographic examination of modern flow deposits collected from the eel shelf reveals that resultant beds possess a microstratigraphy consistent with our hypothesis a silt rich basal subunit with curved ripple laminae abruptly overlain by a subunit composed of continuous intercalated silt clay laminae and an upper clay rich drape analyses of beds from ancient mud rich outer shelf and basinal successions cleveland ironstone jurassic uk and mowry shale cretaceous united states show that they too contain beds with this three part organization suggesting that such flows were active in these ancient settings too recognition of these microstructures in these ancient mud dominated successions demonstrates that sediment in these settings was commonly reworked and transported advectively downslope by high energy events contrasting with previous interpretations of these units that deposition was dominated by quiescent suspension settling identification of these recognition criteria now allows the products of this newly recognized sediment dispersal mechanism to be identified in other shale dominated successions

holocene evolution of the song hong red river delta system northern vietnam abstract the song hong red river delta located on the western coast of the gulf of bac bo tonkin in the south china sea formed as a result of the song hong sediment discharge throughout the holocene the river s sedimentary basin upstream from the delta plain is not large the delta plain comprises emerged tidal mangrove flats formed during the sea level highstand at 2 3 m 6 4 cal kyr bp and a beach ridge strandplain with straight to lobate beach ridges on the landward and seaward sides of the delta plain respectively the delta affords us the opportunity to examine river mouth morphodynamics comprehensively in relation to sediment discharge and sea level changes in this paper we describe the holocene evolution of the song hong delta system and the river mouth morphodynamics on the basis of seven sediment cores each 30 70 m long taken from the delta plain during 1999 2001 and 101 radiocarbon dates obtained from the core sediments sediments from the seven cores consisting of incised valley fills since the last glacial maximum can be divided in ascending order into fluvial sediments composed of gravelly sand and mottled clay tide influenced estuarine sediments containing shell and wood fragments and deltaic sediments composed of tide influenced sand and mud deposits in which the contents of sand and wood fragments increase upward by applying sequence stratigraphic concepts a transgressive surface can be identified at the gravelly sand mottled clay boundary and the maximum flooding surface can be identified at the estuarine deltaic sediments boundary the lowstand systems tract transgressive systems tract and highstand systems tract record 15 15 9 and 9 0 cal kyr bp respectively during the past 9 kyr the majority of the sediment discharged by the song hong accumulated in the incised valley and enhanced progradation at the river mouth the river mouth prograded from the bay head toward the gulf and its morphology changed from funnel shaped 9 6 cal kyr bp to straight 6 2 cal kyr bp and finally to lobate 2 0 cal kyr bp the morphological change from a funnel shaped to straight coast is interpreted to have been closely related to a hydrologic regime shift from a tide dominated bay head setting to a wave influenced open coast setting the cessation of the sea level rise at 6 cal kyr bp may have played only a small role in the change of river mouth morphology because the progradation rate decelerated from 22 to 4 m yr instead of accelerating at that time the river mouth morphodynamic change from straight to lobate was largely caused by an increase in the song hong sediment discharge from 17 27 9 2 cal kyr bp to 49 million t yr 2 0 cal kyr bp as a result of anthropogenic deforestation along the upper reaches of the song hong