deposits from wave influenced turbidity currents pennsylvanian minturn formation colorado u s a turbidity currents generated nearshore have been suggested to be the source of some sandy marine event beds but in most cases the evidence is circumstantial such flows must commonly travel through a field of oscillatory flow caused by wind generated waves little is known however about the interactions between waves and turbidity currents we explore these interactions through detailed process oriented sedimentological analysis of sandstone event beds from the pennsylvanian minturn formation in north central colorado u s a the minturn formation exhibits a complex stratigraphic architecture of fan delta deposits that developed in association with high topographic relief in a tectonically active setting an 20 35 m thick unconformity bounded unit of prodelta deposits consists of dark green shale and turbidite like sandstone beds with tool marks produced by abundant plant debris some of the sandstone event beds most abundant at distal localities contain reverse to normal grading and sequences of sedimentary structures that indicate deposition from waxing to waning flows in contrast proximal deposits in some cases less than a kilometer away contain abundant beds with evidence for deposition by wave dominated combined flows including large scale hummocky cross stratification we interpret the majority of these event beds as a record of deposition from hyperpycnal flows i e turbidity currents generated directly from highly concentrated river plumes which accelerated and decelerated in response to a rising and falling flood discharge additional support for this interpretation includes the following 1 a variety of sole marks including flute and gutter casts as well as tool marks made by relatively large up to tens of centimeters across woody debris i e groove prod and chevron marks 2 consistent unimodal orientation of sole marks and abundant ripple cross stratification which indicate strong downslope directed flow 3 a well documented sedimentological framework for the formation of fan delta deposits adjacent to nearby highlands and 4 plant fossils typical of middle to high elevation habitats that are abundant in the turbidite beds but absent in underlying and overlying shoreline and marginal marine deposits which have a separate floral assemblage differences in grain sizes vertical stratification sequences and bed thicknesses between outcrops are interpreted to result from the spatial distribution of wave effects the time history of hyperpycnal flows and the interaction of these processes the latter varied both spatially and temporally and produced a wide range of bed types which are incorporated into a new conceptual model for storm influenced hyperpycnal flows

clinoforms and clinoform systems review and dynamic classification scheme for shorelines subaqueous deltas shelf edges and continental margins abstract clinoforms are inclined and normally basinward dipping horizons developed over a range of spatial and temporal scales in both siliciclastic and carbonatic systems the study of clinoform successions underpins sequence stratigraphy and all efforts to reconstruct the relative partitioning of reservoir seal and source rocks along shoreline to basin floor profiles here we review clinoform research and propose a more systematic description and classification of clinoforms this is a crucial step to improve predictions of facies and lithology distribution within shoreline to continental shelf and abyssal plain successions together with the genesis drivers and dynamics of their constituent sedimentary units four basic clinoform types are here distinguished in delta shorelines lacustrine and marine environments on the basis of their overall spatial and temporal scale morphology outbuilding dynamic and geodynamic and depositional setting 1 2 delta scale clinoforms which in turns are sub divided into shoreline and delta scale subaqueous clinoforms 3 shelf edge clinoforms and 4 continental margin clinoforms delta scale clinoform sets are tens of metres high and typically represent 1 103 kyr with progradation rates ranging from 1 000 100 000 m kyr for shorelines and subaerial deltas to 100 20 000 m kyr for subaqueous deltas shelf edge clinoform sets are hundreds of metres high and are nucleated and accreted in 0 1 20 myr usual progradation rates of 1 100 m kyr by successive cross shelf transits of delta scale clinoforms continental margin clinoform sets are thousands of metres high hallmark key geodynamic crustal boundaries e g continent ocean transition and slowly prograde basinwards in ca 5 100 myr with typical rates of 0 1 10 m kyr as a consequence of the very different progradation rates and of the difficulty of large scale clinothems to backstep during transgressions shorelines are the most dynamic clinoforms with regards to position continental margins the least and shelf edges are intermediate shortly after a transgression therefore the four clinoform types may prograde synchronously along shoreline to abyssal plain transects forming compound clinoform systems during the subsequent regressive cycle however due to the dissimilarity in progradation rates different clinoform types will normally merge progressively with each other giving rise to hybrid clinoforms e g shelf edge deltas and fewer depositional breaks in slope are distinguished along a single shoreline to abyssal plain transect overall all clinoform systems are the result of the dynamic evolution of compound and hybrid clinoforms along a temporal and spatial continuum regulated by the cyclical backstepping of the smaller scale system within natural progradational retrogradational cycles of larger scale clinothem outbuilding all clinothem types may show either an accretionary active or draping passive style depending on the proximity to the sediment source draping clinothems are nearly always composed of condensed fine grained sediments while actively accreting clinothems can be composed of predominantly coarse grained i e reservoir forming or predominantly fine grained i e non reservoir lithotypes a novel hierarchical classification scheme for both recent and ancient clinoforms is here proposed consisting of 12 classes the four basic clinoform types delta scale shoreline delta scale subaqueous shelf edge and continental margin are sub divided into eight accretionary active and draping passive sub types 8 division each accretionary sub type is then sub divided into a sandstone prone and mudstone prone variant 12 division which can be at least tentatively predicted on the basis of the clinoform morphology even in the absence of direct stratigraphic logs

confounding effects of coral growth and high sst variability on skeletal sr ca implications for coral paleothermometry massive corals offer continuous records of climate locked within their skeleton with the most commonly applied paleo thermometer being sr ca recently however problems with sr ca thermometry indicate that the intrinsic variance of single core sr ca time series differs between cores here we compare the sr ca records and growth parameters of two porites lutea colonies sampled from the same reef zone 0 72 km apart with two gridded sst datasets ersst and hadisst off ne madagascar specifically we address seasonal and interannual variability as well as trend differences between records over the same 43 year period the two gridded sst datasets showed strong seasonality and weak positive enso anomalies on a slow 43 year warming trend at significantly different rates both the coral sr ca records showed the same clear seasonality and similar amplitudes in sst however on interannual timescales they displayed diverging 43 year sr ca trends and opposite responses to weak enso anomalies moreover their growth response also differed as one coral showed increasing extension calcification rates and sr ca ratios cooling over the 43 years while the other coral showed decreasing extension calcification rates and sr ca ratios warming further during positive enso events the calcification rates of the two corals were negatively correlated while skeletal density anomalies were opposite possible explanations to why these corals are so different may be related to the corals growth response to sst changes the growth response of individual corals to increasing sst seems to be opposite which in turn are likely related to biological factors consequently coral growth responses explain much of the inter colony sr ca variability

insights from stratigraphic modeling mud limited versus sand limited depositional systems quantitative stratigraphic modeling provides new perspectives on the controls on basin fill stacking patterns gross lithology distributions and submarine fan deposition in siliciclastic systems our modeling relates basin fill geometries to the ratio of space creation vs sediment supply facies components differentially distribute sand mud mixtures below rising base level surfaces across a basin profile we model alluvial architecture shoreline position shelf width and the occurrence of turbidite sands as a function of relative base level rise and varying receiving basin geometries slope unconformities and onlapping submarine fans are the erosional and depositional responses to changing basin physiography sediment budgeting reveals two types of siliciclastic systems sand limited systems develop in shallow basins or on basin margin platforms have broad muddy wave graded shelves and are subject to exposure and major basinward shifts of shoreline with minor sea level falls mud limited systems develop during progradation into deep water basins have narrow shelves with turbidites in a base of slope position and are not particularly susceptible to major basinward shifts in facies we emphasize the fundamental importance of basin physiography and lithology budgeting as well as sea level in contrast to eustatically based models in addition to accommodation and sediment supply alluvial architecture and basin depth also act as primary controls on shelf width basin fill geometry and submarine fan deposition

micromorphological and physico chemical analyses of cultural layers in the urban soil of a medieval city a case study from krakow poland abstract this study assessed the impact of human activity on the properties of urban soils and the formation of cultural layers cls over several hundred years by examining the micromorphological physical and chemical features of those soils the study relied on a soil profile exposed during archaeological excavations carried out in the main market square mms of krakow poland in 2007 two parts of the profile were distinguished the upper section of the soil profile was composed of 13 cultural layers while the base layer was composed of macroscopically unchanged natural soil cls with similar soil textures clearly differed from the natural horizons nhs exhibiting higher organic carbon corg total nitrogen nt caco3 and available phosphorus pol levels the ranges of cl corg nt caco3 and pol levels are 14 3 118 g kg 1 1 1 10 6 g kg 1 10 5 79 0 g kg 1 and 163 510 mg kg 1 respectively while nh levels are 0 39 5 5 g kg 1 0 13 0 54 g kg 1 1 2 2 5 g kg 1 and 50 1 214 mg kg 1 respectively cls were characterised by lower ph values compared to nhs an a horizon development index adi was used to assess the degree of advancement of pedogenesis in the different layers additionally correlation coefficients between adi and the pol content as well as between adi and the corg content were calculated a micromorphological assessment revealed differences between the structural makeups voids and c f5 m related distributions of cls and nhs a greater number of artefacts were found in cls compared to nhs including fragments of bones ash and black carbon bc the presence of artefacts decreased gradually in the buried soil horizons giving way to bc which is the most stable organic compound found in soil the study also demonstrated the role of cl in the storage of organic carbon stocks in urban soils

a log normal spectral analysis of inorganic grain size distributions from a canadian boreal lake core towards refining depositional process proxy data from high latitude lakes better methods for interpreting grain size spectra will enhance current understanding of past transport depositional processes a high resolution inorganic grain size dataset has been measured from a freeze core extracted from alberta lake e a boreal fresh water lake 40 km east of the athabasca oil sands in north eastern alberta canada the grain size spectra are remarkably consistent throughout the core exhibiting a structure comprising six persistent grain size distributions below ca 250 m plus a rare medium sand distribution automated deconvolution of the grain size spectra produced poor results constraining the modes of two of the distributions produced deconvolution solutions that were statistically excellent and consistent with the structure of each spectrum statistical analysis of the constrained solutions indicates that deconvolution successfully extracted independent grain size populations conversely the multimodal spectra generate traditional measures for example mean grain size that are inconsistent combinations of different individual populations and thus are poor proxies of transport depositional processes alberta lake e is situated in a boreal wetland landscape where sediment delivery is dominated by overland flow transport during spring melt this context means that the alberta lake e grain size spectra can be interpreted to reflect i a bedload component transported during short duration high discharge events that reflect the intensity of the melt and ii a finer suspended load component representing material whose magnitude is controlled by the volume of the spring melt stratigraphically bedload and suspended load populations demonstrate different short wavelength and long wavelength cyclicity suggesting that spring melt is likely to be driven by cyclic external forcing factors the links between the grain size spectra and spring melt have potential for generating proxy records that better capture the external controls over spring melt in boreal systems and the risks associated with these energetic hydrodynamics this is exemplified by the coarsest alberta lake e distributions which indicate that more intense spring melt dynamics occurred in pre historical times this article is protected by copyright all rights reserved

sedimentation by river induced turbidity currents field measurements and interpretation turbidity currents initiated from spring runoffs of an influent river were observed in the upper region of a reservoir in hokkaido japan by measuring water temperature velocity and suspended sediment concentration their profiles offer some physical parameters for the sedimentary conditions assuming the turbidity currents to be quasi uniform the bottom sediment deposited by the turbidity currents was then collected by a portable core sampler the bottom sediment consists of more than 90 silt and clay and thus offers a hydraulically smooth bed for shear flow a plane bed as a bed configuration was formed on the reservoir bed probably because of the low shear velocity and small grain size of sediment using a graphic method with log normal probability paper the bottom sediment is divided into several overlapping log normal subpopulations grain size analysis indicates that the bottom sediment may be regarded as cohesionless criteria for complete deposition of transported grains can then be incorporated into the extended shields diagram giving the minimum shear stress to erode bottom sediment applying the new diagram to the grain size distribution of the bottom sediment it is suggested that each of the log normal subpopulations was deposited in each of four different modes of deposition i e traction saltation or intermittent suspension suspension and suspension under equilibrium the last mode may be observed under a sedimentary condition where upward flux of suspended sediment by eddy diffusion is almost equal to its depositional flux due to gravity the mean and critical grain sizes for bottom sediment and each of the corresponding subpopulations decrease consistently with an increase of fd2 log10re fd is the densimetric froude number and re is the flow reynolds number correlates inversely with shear velocity which bears a linear relationship to mean velocity these results lead to the conclusion that relatively fine suspended sediment is deposited as a result of decreasing bottom friction with a relative decrease of turbulent energy

geometry and facies of tertiary clinothems spitsbergen sandstone clinothems from the battfjellet formation palaeogene on spitsbergen are locally exceptionally well preserved along depositional dip parallel mountainsides the clinothems are more than 1 km wide and more than 100 m thick superposition of several sandstone clinothems separated by mudstones reflects repeated shoreline progradation and transgression deposition took place partly on post transgressional depositional shelves and partly by contributing seaward sloping wedges or clinothems to a ramp progradation shorelines dominated both by mouth bar and shoreface environments have been identified the clinothems are organized into an overall progradational architecture with a geometry having features in common with progradational seismic facies

the ratio in the cenozoic bengal abyssal fan sediments and its use as a paleostream energy indicator abstract the tio 2 al 2 o 3 ratio in the cenozoic bengal abyssal fan sediments displays decisive potential as a paleostream velocity indicator the reason for this is that even in the finest fan suspendates hydrodynamic sorting determines the amounts of heavy tio2 rich minerals relative to lighter al2o3 rich clay minerals in five deep sea drilling project cores 213 217 which have been recovered in and south of the bay of bengal tio 2 al 2 o 3 ratios increase linearly with time from the late miocene to recent the increase reflects fan progradation and intensified bottom current activity on the southern bengal fan these processes are related to the himalayan elevation by factors such as the maturation of northern india river systems evolution of orographic monsoon rains and elevation attributed increases in denudation rates

basin floor fans in the north sea sequence stratigraphic models vs sedimentary facies discussion original article shanmugan g r b bloch s m mitchell g w j beamish r j hodgkinson j e damuth t straume s e syvertsen and k e shields 1995 aapg bulletin v 79 p 477 512

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

eocene clinoform growth in front of a storm wave dominated shelf central basin spitsbergen no significant sand delivery to deepwater areas abstract eocene shelf slope clinoforms on spitsbergen reflect asymmetric basin infill across the coastal plain shelf slope and deepwater segments of a foreland basin although four main types of clinoforms are recognized in the basin this study focuses on clinoforms generated by a storm wave regime on the shelf margin the key aspect of this type of clinoform type 3 is that only modest volumes of sand were delivered across the shelf edge onto the slope and little or no sand onto the basin floor despite the sand prone nature of the sediment delivery system right to the shelf edge the sedimentology and geometry of a series of such clinoforms are documented along a continuously exposed outcrop transect some 800 m high and 4 km long sandstone units of individual clinoforms are 2 12 m thick and are separated by thicker shale clinothems have subhorizontal topset and bottomset segments and steeper mid portions and are up to 150 m high nearly an order of magnitude higher than the deltas and shorefaces that constructed them this clinoformal configuration is thus interpreted to reflect shelf shelf edge slope and base of slope depositional environments and water depths at least as great as the decompacted clinoform amplitudes exposed shelf segments dip up to 0 4 degrees whereas slope segments some 2150 m wide dip up to 4 degrees the shelf and upper slope reaches of clinothems consist of hummocky and swaly cross stratified sandstone units without any significant interbedded shale on the middle slope and below these sandstone units become finer grained are ripple and plane parallel laminated and separated with interbedded shale individual topsets of clinothems are interpreted to have formed by strandplain or wave dominated delta progradation across the morphological shelf platform during short periods of sea level stillstand or slight fall the shale units immediately above sandy clinothems developed during longer intervals of relative sea level rise when the wave dominated shoreline retreated back across the shelf platform the long term trajectory of shelf margin growth shows a significant aggradational component during overall progradation compared to other clinoforms in this same basin where the sediment delivery system was fluvially driven and brought great volumes of sand onto the basin floor and slope respectively storm wave generated clinoforms brought only limited sand to the upper slope and little or no sand to the basin floor

basin floor fans of the central tertiary basin spitsbergen relationship of basin floor sand bodies to prograding clinoforms in a structurally active basin

nummulitic banks in the upper lutetian buil level ainsa basin south central pyrenean zone the impact of internal waves nummulites a particularly abundant and diverse genus of larger benthonic foraminifera formed huge accumulations banks during the eocene which are often good hydrocarbon reservoirs especially in north africa despite their economical interest these accumulations are not well understood and their origin is still under discussion reasons for this debate are the absence of living nummulites accumulations and the high variability of facies including the size shape and extension of the banks which reflect the array of processes controlling sediment production and accumulation the nummulitic banks near santa maria de buil in the ainsa basin south pyrenean foreland basin are composed of recurrent facies associations within mappable bed units bounded by physical surfaces the depositional processes that produced the nummulites deshayesi accumulations are interpreted considering the shape of the banks the type of bounding surfaces the distribution of sedimentary textures nummulites test shapes and the associated skeletal components within the banks this integrative analysis indicates that nummulitic banks accumulated from mass flows with very poor sediment sorting textural and compositional differences among banks suggest that globose nummulites thrived in the shallower part of the mesophotic zone with abundant nummulithoclasts whereas flat nummulitic forms thrived in deeper mesophotic clay dominated settings interbedded with nummulitic banks coral biostromes and coral mounds bearing operculina discocyclina and asterocyclina represent in situ accumulation near the base of the photic zone internal waves waves that propagate along the pycnocline are thought to be the triggering mechanism for the density flows internal waves and induced bottom currents are sporadic but strong enough to bring sediments into suspension in contrast to surface waves both fair weather and storm whose impact is strongest near the sea surface and decreases with bathymetry the impact of internal waves is usually strongest in the mid shelf region and weaker in shallow water this explains the compositional character of the nummulitic banks

architecture of the tectonically influenced sobrarbe deltaic complex in the ainsa basin northern spain abstract the syn tectonic sobrarbe deltaic complex eocene of the ainsa basin spanish pyrenees is confined by lateral thrust ramps and influenced by intra basinal growth anticlines six facies associations have been distinguished within the deltaic complex i slope marls and turbidite sandstones ii distal delta front silty and bioturbated sandstones iii proximal delta front and delta plain deposits tidal inlet tidal flat mouth bar bay distributary channel and floodplain environments iv biogenic deposits at flooding surfaces v collapse zone sediments and vi nummulite dominated shallow marine carbonates the deltaic complex comprises four composite sequences which each contain a number of minor sequences of the genetic maximum flooding surface bounded type regressive unconformities and their correlative surfaces separate the composite sequences cs and each cs can be divided into lowstand transgressive and highstand components at the base the comaron cs is a wnw prograding deltaic complex containing six minor sequences characterized by basinward stepping sandstone wedges separated by transgressive mudstones double regressive unconformities are often associated with these sandstone wedges proximally in the basin growth of the intra basinal arcusa anticline caused gentle folding of the comaron cs and syn growth strata at the base of the overlying las gorgas cs contain a prominent forced regressive sandstone wedge the las gorgas sandbody and display thinning of bedsets onto the crest of the anticline moreover it can be demonstrated that relative sea level rise took place in the growth synclines at the same time as a fall in relative sea level occurred on the growth anticlines the tectonic deformation caused a shift in the direction of deltaic progradation towards the north northwest as demonstrated by the well developed clinoforms in the highstand sequence set of the las gorgas cs a second phase of tectonic activity this time triggering large scale collapse of the delta front occurred at the transition between the las gorgas and barranco el solano cs tilting of the basin floor led to the development of coeval transgressive and regressive strata separated by a fulcrum line of zero net vertical movement of the shoreline in the post tilt phase reduced sediment supply and accelerated subsidence led to widespread transgression and a change from clastic to carbonate dominated sedimentation this phase was terminated by a gradual increase in sediment supply causing progradation of a mixed clastic carbonate system dominated by large nummulite banks and bioturbated shoreface marls and sandstones finally a pronounced fall in relative sea level associated with the transition to the buil cs triggered slope instabilities and eventually established fluvial conditions all over the study area with the exception of the anticline crests the relatively high rate of tectonic subsidence in the study area suppressed relative sea level falls resulting in development of discontinuous lowstand strata and bounding surfaces the segmented nature of many regressive unconformities may be related to incremental growth of thrust related structures and each segment is separated from neighbouring segments by gaps of limited vertical and lateral displacement precursors of progressive unconformities are seen in the upper proximal part of the comaron cs by downdip fanning and updip convergence of minor sequences these differentially tilted stratal units provide reliable indicators of syn sedimentary tectonism

anatomy of shelf deltas at the edge of a prograding eocene shelf margin spitsbergen although shelf edge deltas are well imaged seismic features of holocene and pleistocene shelf margins documented outcrop analogues of these important sand prone reservoirs are rare the facies and stratigraphic architecture of an outcropping shelf edge delta system in the eocene battfjellet formation spitsbergen is presented here as well as the implications of this delta system for the generation of sand prone shelf margin clinoforms the shelf edge deltas of the battfjellet formation on litledalsfjellet and hogsnyta produced a 3 5 15 km shelf edge attached slope apron 70 m of sandstones proximally tapering to zero on the lower slope the slope apron consists of distributary channel and mouth bar deposits in its shelf edge reaches passing downslope to slope channels chutes that fed turbiditic lobes and spillover sheets in the transgressive phase of the slope apron estuaries developed at the shelf edge and these also produced minor lobes on the slope the short headed mountainous rivers that drained the adjacent orogenic belt and fed the narrow shelf and the shelf edge position of the discharging deltas made an appropriate setting for the generation of hyperpycnal turbidity currents on the slope of the shelf margin the abundance of organic matter and of coal fragments in the slope turbidites is consistent with this notion evidence that many of the slope turbidites were generated by sustained turbidity currents that waxed then waned includes the presence of scour surfaces and thick intervals of plane parallel laminae within turbidite beds in the slope channels and thick spillover lobes with repetitive alternations of massive and flatlaminated intervals the examined shelf edge to slope system now preserved mainly below the shelf break and dominated by sediment gravity flow deposits has a threefold stratigraphic architecture a lower progradational part in which the clinoforms have a slight downward directed trajectory a thin aggradational zone and an upper part in which clinoforms backstep up onto the shelf edge a greatly increased density of erosional channels and chutes marks the regressive to transgressive turnaround within the slope apron and this zone becomes an angular unconformity up near the shelf edge this unconformity with both subaerial and subaqueous components is interpreted as a sequence boundary and developed by vigorous sand delivery and bypass across the shelf edge during the time interval of falling relative sea level the studied shelf margin clinoforms accreted mostly during falling stage sea level below the shelf edge but the outer shelf later became estuarine as sea level became re established above the shelf edge

a snapshot of climate variability at tahiti at 9 5 ka using a fossil coral from iodp expedition 310 1 the integrated ocean drilling program iodp expedition 310 recovered drill cores from the drowned reefs around the island of tahiti 17 40 s 149 30 w many of which contained samples of massive corals from the genus porites herein we report on one well preserved fossil coral sample a 13 6 cm long porites sp dated by uranium series techniques at 9523 33 years monthly 18o and sr ca determinations reveal nine clear and robust annual cycles coral 18o and sr ca determinations estimate a mean temperature of 24 3 c 3 2 c colder than modern for tahiti at 9 5 ka however this estimate is viewed with caution since potential sources of cold bias in coral geochemistry remain to be resolved the interannual variability in coral 18o is similar between the 9 5 ka coral record and a modern record from nearby moorea the seasonal cycle in coral sr ca is approximately the same or greater in the 9 5 ka coral record than in modern coral records from tahiti paired analysis of coral 18o and sr ca indicates cold wet warm dry interannual anomalies opposite from those observed in the modern instrumental record

the non tropical coral cladocora caespitosa as the new climate archive for the mediterranean high resolution weekly trace element systematics abstract high resolution weekly laser ablation icp ms trace element analyses b sr u mg ba are reported for the scleractinian coral cladocora caespitosa collected from the northern adriatic sea geochemical ratios sr ca b ca mg ca u ca ba ca were measured in a 38 mm long 10 years growth external coralline portion wall region and generally exhibit a close relationship with the in situ measured weekly fortnightly data on sea surface temperature sst available for the last 6 years in particular b ca ratios tuned to fine scale variations in sst show a high degree of correlation r 0 856 n 136 with sst and indicate that coral calcification only occurs above a minimum temperature threshold of 14 16 c in addition the ranges of trace element variability are larger than those typically recorded in tropical corals consistent with the large seasonal variations in sst of the adriatic this study thus demonstrates the feasibility of extracting and exploiting high resolution geochemical records from non tropical corals such as c caespitosa as a proxy for sst

process regime changes across a regressive to transgressive turnaround in a shelf slope basin eocene central basin of spitsbergen abstract the sedimentological architectural and stratigraphic database from one investigated shelf margin clinothem complex in the eocene central basin of spitsbergen suggests that dominating process regimes and facies products may change several times during a sea level cycle even though the basin wide processes are constant continuous mountainside exposures were investigated by a combination of walking out of stratigraphic surfaces and geometrical elements closely spaced detailed vertical sections and tracing on helicopter photo mosaics the clinothem complex represents a regressive to transgressive shoreline complex and consists of five clinothem sets recognized by specific stacking patterns and sedimentary facies the regressive part preserves wave and river dominated deltaic deposits in a progradational to aggradational stacking pattern the delta clinothems consist of tide influenced distributary channels wave and hyperpycnal flow dominated mouth bars that on the shelf sourced turbidite filled slope channels and slope lobes the transgressive part of the clinothem complex preserves strongly tide dominated estuarine deposits underlain by tidal ravinement surfaces that cut down into deposits of wave dominated deltas this change in facies product on the inner shelf from wave to tidal at the regressive to transgressive turnaround was however not a basin wide process change inasmuch as the distributary channels also reflect tidal influence this suggests that tidal currents were present only in areas protected from waves and amplified by the lateral confinement of the estuary there was a process regime change on the middle to outer shelf from wave dominated highstand and falling stage delta complex to river dominated and wave influenced early lowstand delta complex the delta complex prograded across the shelf during highstand and during falling stage the relative sea level fall forced the deltas out to shelf edge the early lowstand delta mouth bars are volumetrically dominated by hyperpycnites indicating dominance of riverine processes the proportion of the hyperpycnal flow deposits decreased during the late lowstand and the delta complex became wave dominated anew the process regime change from wave dominance to fluvial dominance and back to wave dominance is interpreted to have occurred due to the seaward and then landward shift of the feeding river system whereas the tidal effects were dependent on shelter from waves and on the shoreline configuration

anthropogenic soils in yaroslavl central russia history development and landscape reconstruction abstract the town of yaroslavl is located in central russia about 280 km n e of moscow the russian prince yaroslav the wise founded the town about 1000 years ago and gave his name to it the goal for archaeological and paleopedological research was to reconstruct the history of the place from the very beginning of anthropogenic impact several buried soils and cultural layers were studied using morphological chemical physical microbiomorphic and radiocarbon analyses two ancient ramparts were excavated in the central part of the modern town the results of paleoanthropogenic soils study in yaroslavl allow reconstruction of the early history of the locality initially the area was characterized by typical podzols supporting coniferous forests following the first stage of anthropogenic impact cutting of forests ploughing new agricultural soils formed here after that there was a period practically without any impact and natural soil formation processes began the second stage of anthropogenic activity started after approximately 250 350 years and a new ploughing horizon formed two ramparts were built one after another over that soil which was thus covered over and preserved for history the differences in the properties of soils from the site confirm that people arrived there over 1000 years ago perhaps 300 400 years earlier and that the town was built on soil that had already undergone several stages of cultivation a long history produced different natural and cultural layers subsoils with specific properties in all stages of development natural or artificial

three dimensional reconstruction of geological surfaces an example of growth strata and turbidite systems from the ainsa basin pyrenees spain the external and internal geometry of four turbidite systems outcropping around the buil syncline ainsa basin spanish pyrenees has been reconstructed with reservoir scale resolution in three dimensions 3 d the irregular geometry of the syncline and the resolution required for the reconstruction cannot be resolved with cross sections therefore reconstruction has been carried out with a new methodology that applies a 3 d dip domain geometrical model and 3 d restoration techniques to achieve reservoir scale resolution in kilometric scale reconstructions this methodology is aimed at resolving 3 d geometries in folded areas and regions with variable thickness stratigraphy the 3 d reconstruction of the buil syncline reveals the synsedimentary growth of an intrabasinal anticline and the foreland lithospheric flexure associated with tectonic loading north of the ainsa basin

an evaluation of quantitative reconstruction of past precipitation records using coral skeletal sr ca and δ18o data abstract coupled records of 18o and sr ca in porites coral have been used to derive hydrological conditions by removing the sr ca inferred temperature component from the 18o signal nanwan a semi enclosed bay in southern taiwan provides an opportunity to demonstrate the feasibility of quantitatively reconstructing past precipitation history recurrence of seawater 18o offsets between wet and dry seasons in the early 1990s is well correlated with the precipitation record even though the hydrological signal only accounts for 20 of the total annual coral 18o variation of ca 1 offsets can be found in the residual 18o of modern corals after removing the thermal effect which contributes to the other 80 the observed timing and amplitude of the seasonal seawater 18o offsets in nanwan and their correlation with precipitation are reproduced by hydrological models in the mid holocene the seasonal anomaly of residual 18o was twice that of the modern value based on the 9 yr sr ca 18o data recorded in a 6 73 ka porites coral hydrological models suggest an annual rainfall of 1800 3000 mm yr at the window during mid holocene 20 higher than that of the average of 30 yr modern instrumental records of 1500 2500 mm consistent with the qualitative pollen record from lake sediments the seasonal decrease of residual 18o in 5 of 9 yr was earlier than the increase of the coral sr ca inferred temperature which implies that these rainy seasons probably occurred from the early mid spring to mid summer earlier than that from late spring to late summer today the driving force may be related to the changes of solar insolation and the east asian monsoon it is cautioned that the variability of hydrographic conditions imposes restrictions on a precise calculation of the amount of paleo precipitation the dynamic nature of local tectonics monsoons and water circulation should be further addressed to precisely quantify precipitation over the past 10 000 yr from coral geochemical records

climate forcing of fine grained deep marine systems in an active tectonic setting middle eocene ainsa basin spanish pyrenees abstract a multi proxy approach to understand environmental change in deep time was undertaken on about 150 m of core from a 230 m long middle eocene core from the ainsa basin spanish pyrenees representing deep marine siliciclastic sediments using detailed sedimentary logging high resolution multi element xrf geochemistry total organic carbon and stable carbon isotopes the well a6 was drilled as part of an industry university consortium through siltstones fine very fine grained sandstone turbidites and hemipelagic structureless mudstones that were deposited as overbank and off axis deposits from a sandy submarine fan and interfan deposits for comparative mineralogy between the sandstone turbidites and siltstones scanning electron microscopy sem and x ray diffraction xrd were undertaken on selected samples the sandstone turbidites show enrichment of detrital elements such as si zr and ti that can be linked to greater quartz and heavy mineral content compared with adjacent siltstones structureless hemipelagic mudstones comprise mainly clay minerals and carbonate we interpret the sandstone turbidites as from hyperpycnal flows during high river sediment discharge whilst hemipelagic mudstones resulted from the suspension fall out of hypopycnal flows cyclostratigraphic analysis of the core reveals milankovitch cyclicity at frequencies of 0 03 cycles m short eccentricity 0 09 cycles m obliquity 0 15 cycles m precession couplet and 0 19 cycles m precession couplet orbital parameters appear to have controlled the cyclic delivery of coarser grained sediment by turbidity currents two equally plausible depositional models both as milankovitch driven can explain the cyclical changes in the deep marine sediments 1 climatic cycles with humid periods of enhanced chemical weathering increased storminess and greater riverine run off leading to high sediment flux to the deep basin as sandstone turbidites 2 climatic cycles with cooler conditions linked to high frequency small scale eustatic sea level fluctuations with lowstand shelf edge delta progradation resulting in greater volumes of coarse detrital sediment to the seafloor by hyperpycnal flows this study provides an insight into the likely depositional effects of orbitally induced climate change on the nature and delivery of terrigenous sediment into deep marine environments

regional synthesis of the productive neocomian complex of west siberia sequence stratigraphic framework we have developed a regional sequence stratigraphic framework for the productive neocomian complex of central west siberia sixteen depositional sequences have been identified on the basis of analysis of regional seismic lines and well logs a dip oriented well log transect that was constructed across the nizhnevartovsk and surgut arches reveals detailed features of the stratigraphic architecture and depositional history of the neocomian section in two dimensional view integration of ammonite biostratigraphic data led to development of a reliable chronostratigraphic framework for our sequence interpretation the neocomian marine complex ranges in thickness from 350 to 700 m and consists of the clinoform lower part and topset packages deposition of the clinoform package occurred during a period of at least 9 m y when clinoforms prograded more than 550 km from east to west progradation occurred through lateral shelf outbuilding mostly during lowstand periods when sandstone units accumulated in shelf edge deltas shoreline shelf systems at the shelf break zone and submarine fans in basinal parts achimov formation periods of progradation were commonly interrupted by regional transgressions with significant retreat of depocenters landward over the shelf up to 200 km the transgressive systems tracts on the shelf are laterally extensive shale horizons that represent useful markers for correlation the overlying highstand deposits are interpreted as thin but broad sand prone packages with generally progradational appearance the lowstand systems tracts on the shelf are locally present as fluvial sandstones that are incised into underlying highstand deposits

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

sea level fall below the shelf edge without basin floor fans a fall of sea level to below the shelf edge formation of type 1 sequence boundary increases greatly the likelihood of sand delivery into deep water basin floor areas although an unusually high sediment supply can bring significant volumes of sediment to the shelf edge at any time an eocene ypresian data set from seismic scale mountainside outcrops of shelf slope clinoforms illustrates that a fall of sea level below the shelf edge produces significant sand accretion on the shelf margin but brings no sand out onto the basin floor fall and subsequent rise of relative sea level are documented by the style and topographic position of successive shelf edge to slope clinoforms each representing a shelf edge delta with its greatly extended slope apron of turbidite lobes sheets and chutes a downslope shift of clinothems at the shelf edge and a headward cannibalization of the oldest perched slope deltas are the criteria for recognition of 1 the time interval of sea level fall and 2 the position of sea level below the shelf edge the lowest sea level is recorded by the most basinward clinothem set with a high density of erosive turbidite chutes at its upper surface the sequence boundary wave eroded terraces at its updip near shelf edge end identify the shoreline position at lowest sea level aggradation and landward stepping of clinothems reflect subsequent rise of relative sea level the fall to rise configuration and especially the occurrence of peak erosion at the time of lowest sea level are compelling evidence for placing the type 1 sequence boundary at the fall to rise turnaround and not along the surface onto which the clinothems downlap the excellent exposure downdip as well as along strike of the clinoform complex demonstrates the absence of sand accumulation beyond the base of slope the slope turbidites were produced from dilute nonignitive flows and caused significant shelf margin accretion the data show that such slopes can be extremely sand prone and that sea level fall below the shelf edge does not necessarily result in basin floor sand deposits beyond the base of slope particularly where canyons have not been eroded into the slope

sea surface temperature and salinity reconstruction from coral geochemical tracers massive scleractinian corals secrete an aragonitic skeleton which incorporates a large array of chemical tracers corals present several advantages for palaeoclimate research they grow continuously and can live up to 1000 years they are easy to date and they can be sampled at high resolution weekly to monthly resolution both live and fossil corals can be collected in the field in the past two decades significant efforts have been made to identify robust tracers of sea surface temperature sst and salinity sss in corals to date sr ca and 18o are considered to be the most reliable sst tracers although changes in seawater 18o can significantly alter sst reconstructed from coralline 18o because these variations in seawater 18o can be linked to sss changes this initial problem can in fact be turned into an advantage and provide us with an sss tracer the sst component in the coral 18o signal can either be evaluated through sr ca measurements or in some case simply filtered out however there is still much uncertainty concerning the exact mode of incorporation of trace elements and stable isotopes into the coral skeleton the effects of growth rate light intensity feeding habits ph and water chemistry are still poorly documented a review of the strength and weaknesses of sr ca and 18o is presented together with some examples of sst and sss reconstructions other potential sst tracers are also reviewed it is expected that the ability to grow corals in aquarium under controlled conditions and that the development of sophisticated analytical techniques at the micrometric level should help us understand better the robustness of each tracers and the factors controlling their incorporation in coral aragonite

turbidite variability and architecture of sand prone deep water slopes eocene clinoforms in the central basin spitsbergen abstract the architecture and turbidite variability within six wedge shaped downslope thinning sand prone slope accumulations are documented from eocene shelf margins on spitsbergen the central basin formed as a small foreland or piggy back basin and the studied turbidites accumulated mainly on the slope portion of sand prone clinoforms that developed during depocenter migration and infilling of the basin the shelf margin clinoforms have amplitudes minimum water depths from 100 to 350 meters and their shelf slope and basin floor segments are well imaged and can be walked out along many of the mountainsides only a small percentage of the clinoforms are sand prone and these developed when sea level occasionally fell to or below the shelf edge of the sand prone clinoforms some had their sand budget partitioned mainly out onto the basin floor basin floor fans but most trapped the sand on the slope only the latter are now visible as downslope thinning wedges some 2 5 3 5 km in downdip extent the turbidites within this type of clinoform have been examined and classified the lower slope to base of slope segment of the studied clinoform complexes are dominated by lobes consisting of broad shallow channels and sheet like turbidites becoming heterolithic and muddy out on the basin floor beds on the lower slope vary from thick up to 4 5 meters ungraded or laminated sandstones to thinner ungraded sandstones with coarse cappings the middle slope segment of clinoform complexes is dominated by narrow channels chutes that feed downslope to progradational chute mouth lobes chutes contain ungraded and laminated sandstone beds up to 3 m thick whereas the chute mouth lobes show alternations of thinner ungraded to laminated or rippled sandstones these lobes become more heterolithic and muddy downslope the shelf edge to upper slope segment of clinoform complexes is dominated by upward coarsening and thickening sheetsands of steep fronted shelf edge deltas the sandsheets of the delta front can be traced updip into mouth bar and distributary channel sandstones it is argued that shelf margin accretion represented by the sand prone slope wedges was achieved mainly by sand laden currents that flooded from the shelf edge as hyperpycnal flows this hypothesis is supported by 1 the direct connection between channel and mouth bar systems at the shelf edge and the turbidites of the slope lobes 2 the systematic progradational character of the slope lobes 3 the absence of large scale slump scars gullies or canyons on the slope and 4 the dominance of a type of turbidite that implies deposition from sustained flow detailed examination of the architecture of one of the slope wedges shows that there are unconformities developed within the stratigraphy below the shelf edge and that these erosional terraces beheaded the deltas perched on the uppermost slope the erosion surfaces indicate fall of sea level to this position despite the magnitude of this fall up to 80 meters the lack of canyons on the slope prevented the construction of basin floor fans such falls of sea level on non canyoned slopes simply promote sand prone accretion of the shelf margin

double and triple depth digging and anthrosol formation in a medieval and modern era city wroclaw sw poland geoarchaeological research on past horticultural practices abstract buried humus rich horizons up to 0 60 m thick poor in archaeological artefacts and other anthropogenic materials were identified during an archaeological rescue excavation conducted at monastery grounds located near the centre of wroclaw sw poland as indicated by historical sources the monks settled in the 18th century in a suburb area which had been used for agriculture and gardening since the middle ages the paper discusses the origin of the thick humus horizon in the context of various concepts of dark earths formation three hypotheses were considered linking the soil formation with 1 natural pedogenesis in alluvial material 2 ancient settlement and human activity resulting in accumulation of materials and 3 past modern agricultural and horticultural activities in order to reveal the origin of this humus rich horizon and investigate the possible involvement of anthropogenic factors in its creation an interdisciplinary research protocol was adopted which involved a historical query and archaeobotanical micromorphological and physico chemical soil analyses it was argued that the studied soil poor in archaeological artefacts is in fact a relatively young anthropogenic soil which had been formed by triple and double depth digging rigosol and enrichment of the soil in certain kinds of anthropogenic material anthrosol but without surface up building typical for soils with plaggic and terric horizons this led to a transformation of the original soil cover increasing the thickness of its a horizon and adapting it for supporting gardens and orchards these practices which most likely took place in the late medieval and modern era period up to the 19th century have been completely forgotten until now in this light the discovered rigosol anthrosol may be considered an artefact of horticultural agricultural land use in the former suburbs which were absorbed by the rapidly growing city during the last century it is also postulated that rigosols anthrosols may be widespread among dark earths in some medieval suburban and present day urbanized areas of cities and should be investigated during archaeological research

clinoform development by advection diffusion of suspended sediment modeling and comparison to natural systems clinoforms are the building blocks of prograding stratigraphic sequences these sig moid shaped surfaces can be found forming today on modem deltas sedimentation rate profiles over the clinoform surface of these deltas show low rates of sediment accumulation on both topset and bottomset regions with a maximum accumulation rate on the upper foreset region we pres ent a model for the formation of clinoforms that relies on the interpretation of modem clinoform sedimentation as a result of the distribution of shear stresses at the mouth of a river model clino form surfaces are generated using an equation for the conservation of suspended sediment concentration together with a conservation of fluid equation for simple time averaged flow velocity fields in the model suspended sediment is advected horizontally into a basin and gravitational settling of sediment particles is counteracted by vertical turbulent diffusion in shallow water shear stresses are too large to allow deposition and sediment bypasses the topset region with increasing water depth near bed shear stresses decrease and sediment is allowed to deposit at the foreset region with gradually decreasing rates toward deeper water this sedimentation pattern leads to progradation of the clinoform surfaces through time the clinoform surfaces produced by the model capture the fundamental morphological characteristics of natural clinoforms these include the gradual slope rollover at the topset and bottomset steeper foreset slopes with increased grain size and an increase in foreset slope through time as clinoforms prograde into deeper water because the parameters controlling the model clinoforms have a direct relation to physical quantities that can be measured in natural systems the model is an important step toward unraveling the physical processes associated with these deposits

linking river flood dynamics to hyperpycnal plume deposits experiments theory and geological implications turbid river plumes entering ocean or lake water of lesser density i e hyperpycnal plumes can plunge to form turbidity currents providing an important link between terrestrial sediment sources and marine depositional sinks a leading hypothesis suggests that hyperpycnal plume deposits accurately record the rising and falling discharge of a flooding river in terms of sediment size grading bedform sequence and deposit thickness which if correct has significant implications for unraveling river dynamics reservoir potential and earth history from marine event beds herein we present one of the first experimental flume studies aimed at testing this hypothesis results indicate that depth averaged hyperpycnal plume velocities can be uncorrelated or even anti correlated with river discharge at certain seabed locations because of translation of the plunge point resulting from temporal variations in discharge and sediment concentration through the duration of a river flood an advection length scale of settling sediment is found to be an important control on hyperpycnal plume deposits where coarse sediment sand is most likely to record multiple flow accelerations and decelerations related to plunge point translation even for a river flood with a single peaked hydrograph in contrast fine sediment mud is relatively insensitive to local plunge point dynamics and is most likely to preserve directly rising and falling river discharge finally it was found that the necessary fluvial sediment concentration to form a plunging plume can be much larger than the concentration typically used assuming density equivalence because of deposition upstream of the plunge point

quantifying the kinematics of detachment folds using three dimensional geometry application to the mediano anticline pyrenees spain the kinematics of detachment folds have been described by three different models 1 hinge migration is responsible for fold amplification 2 fold amplification is due to limb rotation and 3 both hinge migration and limb rotation cause fold amplification a numerical method is proposed to determine which of these mechanisms is responsible for the formation of natural detachment folds this procedure consists of measuring and plotting geometric data collected from cross sections constructed across the termination of a fold where shortening dies out laterally or in an area with a lateral shortening gradient assuming that observed spatial variations in fold geometry reflect temporal geometric evolution the procedure allows determination of equations that govern the kinematics of the particular detachment fold analyzed to validate the results obtained from the application of this technique to natural examples they must be contrasted with other indicators of fold amplification mechanisms such as microstructures mesostructures and syntectonic sediment patterns this analysis is applied to an asymmetric growth fold the mediano anticline in the southern pyrenees of spain and shows that it grew due to limb rotation and minor hinge migration these data coupled with analysis of the growth stratal patterns using reverse and forward modeling techniques are used to derive deformation rates and to display the kinematics of this fold

black carbon in soils and sediments analysis distribution implications and current challenges this review highlights the ubiquity of black carbon bc produced by incomplete combustion of plant material and fossil fuels in peats soils and lacustrine and marine sediments we examine various definitions and analytical approaches and seek to provide a common language bc represents a continuum from partly charred material to graphite and soot particles with no general agreement on clear cut boundaries formation of bc can occur in two fundamentally different ways volatiles recondense to highly graphitized soot bc whereas the solid residues form char bc both forms of bc are relatively inert and are distributed globally by water and wind via fluvial and atmospheric transport we summarize chronologically the ubiquity of bc in soils and sediments since devonian times differentiating between bc from vegetation fires and from fossil fuel combustion bc has important implications for various biological geochemical and environmental processes as examples bc may represent a significant sink in the global carbon cycle affect the earth s radiative heat balance be a useful tracer for earth s fire history build up a significant fraction of carbon buried in soils and sediments and carry organic pollutants on land bc seems to be abundant in dark colored soils affected by frequent vegetation burning and fossil fuel combustion thus probably contributing to the highly stable aromatic components of soil organic matter we discuss challenges for future research despite the great importance of bc only limited progress has been made in calibrating analytical techniques progress in the quantification of bc is likely to come from systematic intercomparison using bcs from different sources and in different natural matrices bc identification could benefit from isotopic and spectroscopic techniques applied at the bulk and molecular levels the key to estimating bc stocks in soils and sediments is an understanding of the processes involved in bc degradation on a molecular level a promising approach would be the combination of short term laboratory experiments and long term field trials

facies architecture and latest pleistocene holocene depositional history of the po delta comacchio area italy abstract integrated sedimentological and micropaleontological study of 16 cores and 137 piezocone penetration tests approximately 40 m deep in the comacchio area enables the documentation of the depositional history of southeastern po plain in the last 30 ka in response to fluctuating sea level sedimentation within an alluvial plain was the dominant feature across the entire study area during the pronounced sea level fall that culminated in the last glacial maximum thin lowstand fluvial sediments form the lower part of a shallow incised valley above the last glacial maximum unconformity whereas a characteristic paleosol separates the last glacial alluvial plain deposits from the overlying postglacial deposits in the interfluves transgressive and highstand deposits show a well developed stacking pattern of retrogradational coastal plain and estuarine and progradational deltaic facies detailed reconstruction of transgressive paleogeography shows evolutionary features that can be useful for refin

the temperature relationship in coralline aragonite influence of variability in and skeletal growth parameters this paper provides an evaluation of two of the most likely pitfalls of sr ca thermometry i e the effect of biogenic cycling of sr vs ca in the surface ocean and the effect of variable extension rate on sr incorporation in coralline aragonite the authors also report calibration of the sr ca temperature relationship for three coral species porites lobata pocillopora eydouxi and pavona clavus collected for the hawaiian and galapagos islands analyses of seawater samples show significant spatial and depth variability in the sr ca ratio the uncertainty introduced by this effect is estimated to be 0 2 degrees c for corals located in tropical oligotrophic waters and potentially larger for corals located in upwelling areas sr ca along two different growth axes of a galapagos pavona clavus with annual extension rates of approximately 6 and 12 mm y respectively indicate an offset of 1 2 degrees c with higher sr ca values associated with slower extension rates the offset observed between the two growth axes may be the result of variations in extension and or calcification rate these results are important in determining past sea surface temperatures for reconstruction of paleoclimates

late quaternary depositional architecture of po and tevere river deltas italy and worldwide comparison with coeval deltaic successions abstract po and tevere rivers form two of the most important deltas of the whole mediterranean area detailed investigations have been carried out in the last decade beneath the present delta plains of these two river systems using borehole data correlation with the aid of radiocarbon dates and other dating methods pollens archaeology a detailed sequence stratigraphic framework has been constructed in both areas especially for the last glacial interglacial cycle regional subsidence combined with short term sea level fluctuations of relatively high amplitude played a fundamental role in creating subtracting accommodation during the long phase of falling sea level which followed the tyrrhenian substage 5e transgressive event a discontinuous record of this phase is present in the subsurface of the po plain whereas poor or no preservation has been detected in the tevere area progradational lowstand wedges accumulated during the last glacial maximum mostly in the central part of the basins far from the present deltas and are lacking in the study areas where a hiatal surface is invariably recorded below the transgressive deposits glacioeustasy exerted a major control on sedimentation in both areas during the latest pleistocene holocene sea level rise infilling of fluvial valleys and rapid landward migration of barrier lagoon systems in the context of wave dominated estuaries characterized the transgressive phase in both po and tevere systems in place drowning and transgressive submergence mechanisms of barrier migration were effective predominantly between 13 5 and 9 ka bp in contrast shoreface retreat was dominant in the late transgressive phase the maximum flooding surface mfs can be traced physically from continental to marine deposits and has similar characteristics in the po and tevere river systems being marked by peat layers or lagoonal deposits at landward locations and by distinctive lithological characteristics and micro and macrofossils assemblages basinwards above the mfs the early highstand systems tract records initially the filling of the lagoons followed by the rapid progradation of wave dominate delta systems and flanking strandplains autocyclic processes such as distributary channel avulsion delta lobe abandonment and local subsidence due to sediment compaction were the fundamental controlling factors on sedimentation during deposition of the hst the stratigraphic architecture of the post glacial po and tevere delta complexes closely resembles the basic facies successions documented from coeval deposits of wave dominated and wave influenced clastic coasts both locally within the mediterranean area and in other parts of the world our study emphasizes however some additional features and major differences with previously published depositional models including i the development of backstepping wave dominated estuaries during transgression ii consistent changes through time in the mechanism of barrier migration iii a later construction of the delta systems with respect to what traditionally considered

sediment facies and late holocene progradation of the mekong river delta in bentre province southern vietnam an example of evolution from a tide dominated to a tide and wave dominated delta abstract the mekong river delta southern vietnam is a typical mixed tide and wave energy delta with a wide delta plain formed during the last 6 ka and is one of the largest deltas in the world three cores were taken from bentre province in the lower delta plain with the objective to describe the sediment facies and to clarify the changes from tide dominated to tide wave dominated delta of the mekong river delta during the late holocene three cores bt1 bt2 and bt3 were obtained in 1997 holocene sediments in bt1 and bt3 with thickness ranging from 10 to 20 m were mainly composed of deltaic sediments unconformably overlying the late pleistocene sediments the bt2 core however consisted of transgressive estuarine sediments covered by deltaic sediments infilling the paleo mekong river incised valley which is more than 70 m deep and was formed during the last glacial period the deltaic sediment facies and succession in the bt2 and bt3 cores taken from the outer delta plain with beach ridges were different from those of the bt1 core taken from the inland delta plain the bt2 and bt3 cores provide a good example of tide and wave dominated delta sediments and were characterized by a coarsening upward delta front facies covered by a fining upward subtidal to intertidal flat facies followed by a coarsening upward foreshore dune facies these changes from the inland delta plain to the beach ridge delta plain were accompanied by changes in progradation rates and subaqueous delta topography caused by increased wave influence

seawater transport during coral biomineralization cation transport during skeletal growth is a key process controlling metal calcium me ca paleoproxy behavior in coral to characterize this transport cultured corals were transferred into seawater enriched in the rare earth element tb 3 as well as stable isotopes of calcium strontium and barium subsequent nanosims ion images of each coral skeleton were used to follow uptake dynamics these images show a continuous region corresponding to new growth that is homogeneously enriched in each tracer isotope ratio profiles across the new growth boundary transition rapidly from natural abundance ratios to a ratio matching the enriched culture solution the location of this transition is the same for each element within analytical resolution the synchronous incorporation of all these cations including the dissimilar ion terbium which has no known biological function in coral suggests that 1 there is cation exchange between seawater and the calcifying fluid and 2 these elements are influenced by similar transport mechanisms consistent with direct and rapid seawater transport to the site of calcification measured using isotope ratio profiles seawater transport rates differ from place to place on the growing coral skeleton with calcifying fluid turnover times from 30 min to 5 7 h despite these differences all the elements measured in this study show the same transport dynamics at each location using an analytical geochemical model of biomineralization that includes direct seawater transport we constrain the role of active calcium pumping during calcification and we show that the balance between seawater transport and precipitation can explain observed me ca variability in deep sea coral

strontium heterogeneity and speciation in coral aragonite implications for the strontium paleothermometer sea surface temperatures ssts have been inferred previously from the sr ca ratios of coral aragonite however microanalytical studies have indicated that sr in some coral skeletons is more heterogeneously distributed than expected from sst data strontium may exist in two skeletal phases as sr substituted for ca in aragonite and as separate srco3 strontianite domains variations in the size quantity or both of these domains may account for small scale sr heterogeneity here we use synchrotron x ray fluorescence to map sr ca variations in a porites lobata skeleton at a 5 m scale variations are large and unrelated to changes in local seawater temperature or composition selected area extended x ray absorption fine structure exafs spectroscopy of low and high sr areas indicates that sr is present as a substitute ion in aragonite i e domains of sr carbonate strontianite are absent or in minor abundance variations in strontianite abundance are not responsible for the sr ca fluctuations observed in this sample the sr microdistribution is systematic and appears to correlate with the crystalline fabric of the coral skeleton suggesting sr heterogeneity may reflect nonequilibrium calcification processes nonequilibrium incorporation of sr complicates the interpretation of sr ca ratios in terms of sst particularly in attempts to extend the temporal resolution of the technique the micro exafs technique may prove to be valuable allowing the selection of coral microvolumes for sr ca measurement where strontium is incorporated in a known structural environment

filter or conveyor establishing relationships between clinoform rollover trajectory sedimentary process regime and grain character within intrashelf clinothems offshore new jersey u s a abstract clinoform geometries and trajectories are widely used to predict the spatial and temporal evolution of sand distribution but most analytical approaches underplay the significance of topset and shelf process regime in determining how and when sediment is conveyed downdip or stored on the continental shelf we present an integrated study of clinoform rollover trajectory and detailed grain character analysis to assess the role of topset process regime in determining sand distribution and sediment character across clinothems this study targets the topset foreset and bottomset deposits of four successive miocene intrashelf clinothem sequences which represent deposition under either river dominated or wave dominated conditions seismic reflection data was combined with core analysis and grain character data derived from 664 samples collected from three cored research boreholes in river dominated clinothems the transfer of coarse grained sediment occurs under both rising and flat to falling clinoform rollover trajectories suggesting that process regime is more important in determining sediment delivery than clinoform trajectory river dominated systems are effective conveyors of sediment into deeper water wave dominated clinothems deposited exclusively under rising clinoform rollover trajectories largely retain sand within topset and foreset deposits wave dominated systems are effective sediment filters notably deposition under either river or wave dominated topset process regimes results in quantifiable differences in grain character attributes along clinoform profiles sediments in river dominated systems are coarser less well rounded and more poorly sorted and show greater intersequence and intrasequence variability than those in wave dominated systems prediction of sediment character is more challenging in river dominated systems this study highlights the need for caution when attempting to predict downdip sand distribution from clinoform trajectory alone and provides a novel perspective into downdip grain character profiles under end member topset process regime conditions the results of this study can be used to better constrain sediment grain size and grain shape distributions in process based forward models and have widespread applications in prediction of reservoir quality in both frontier and mature hydrocarbon basins

coral li mg thermometry caveats and constraints abstract the coral li mg temperature proxy is revisited through an in depth trace element analysis of scleractinians collected live from tropical to polar environments the dataset consists of li ca mg ca sr ca and li mg ratios from 64 coral specimens belonging to 8 different taxa including both reef building zooxanthellate and cold water non zooxanthellate species from a wide range of water temperature 1 to 29 5 c salinity 34 71 to 38 61 and depth 3 to 670 m our results showed that the reliability of the li mg temperature proxy is strongly limited by the organic matter associated with the coral skeleton which is most evident within the green bands observed in tropical corals organic rich bands can double the mg content otherwise present in the skeleton which may ultimately lead to a temperature overestimation exceeding 15 c we found that this bias can be overcome by the treatment of coral skeletons with a specific oxidizing cleaning protocol we also detected the presence of calcite deposits within the aragonite skeleton of some antarctic living coral specimens which strongly affects the robustness of the li mg proxy given its temperature sensitivity of 1 5 c 1 calcite therefore to obtain reliable reconstructions a correction needs to be applied when organic matter and or calcite contamination is present which requires the scrupulous assessment of the integrity of the aragonite prior to geochemical analyses given that some species entrap more organic matter than others and that some are more prone to calcite contamination a taxon related effect is apparent here we show that the tropical species porites spp pseudodiploria strigosa and orbicella annularis and the cold water species madrepora oculata caryophyllia antarctica and flabellum impensum are all suitable candidates for reconstructing seawater temperatures the integrated results across a wide temperature range from extreme cold to tropical shallow waters yield an overall precision for the li mg temperature proxy of 1 0 c as quantified by the standard error of estimates if calculated from the 95 prediction intervals the uncertainty of the temperature estimates is 0 9 c at 1 c 1 5 c at 12 c and 2 6 c at 25 c however the uncertainty for the tropical corals e g porites can be reduced to 0 6 c if a li mg and sr ca multi regression approach is applied

initiation of turbidity currents outcrop evidence for eocene hyperpycnal flow turbidites abstract the most widely used although not as widely documented explanation for initiation of turbidites is the conversion of catastrophic sediment failures into turbidites such instantaneous sediment failures generate short lived surge type flows that deposit turbidite beds described as bouma sequences in this communication we present data from the eocene central basin of spitsbergen that shows turbidite systems that are volumetrically dominated by thick ungraded and laminated sandy turbidite beds deposited by gradual aggradation from sustained flows sustained flows are long lived and more or less continuous they can be generated by a variety of mechanisms e g 1 instability during volcanic eruptions and the consequent remobilisation of unconsolidated material 2 seismically triggered subaerial sliding within the drainage 3 storm surges 4 retrogressive slope failure 5 breaching and 6 hyperpycnal flows our database shows that in the eocene central basin the sustained flows were generated by hyperpycnal flows i e by direct river effluent the hyperpycnal flow turbidites have been recognized on the basis of 1 physical connection between fluvial and turbidite channels at the shelf edge 2 abundance of thick turbidite sandstone beds 3 sand prone nature of the turbidite systems 4 downslope changes of individual thick sandy turbidite beds and their collapsed pinch out segments 5 great abundance of continental material leaves coal fragments in turbidite beds 6 low abundance of associated slumped or debris flow beds and 7 the occurrence of turbidites in systematically accreted shelf margins these features strongly suggest that hyperpycnal flow generated by direct river effluent deposited significant number of turbidite beds in the documented slope and basin floor turbidite successions we also argue that the hyperpycnal flows are preferentially fed into the deepwater slopes beyond the shelf edge during the falling stage and lowstand of relative sea level the turbidite beds were studied in the context of seismic scale 1 15 km dip oriented outcrops by measuring detailed vertical sections following individual beds and packages of beds downslope for distances over 5 km lateral mapping and helicopter taken photomosaics

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

the influence of the evolution of the pyrenees on adjacent basins abstract important thicknesses of syn and post orogenic sediments are observed in the southern part of the aquitaine basin and in the north of the ebro basin their deposition cannot be explained only as a result of the extensional history of the early cretaceous thus the influence of the compression associated with the pyrenees formation upon the subsidence of these basins is studied europe and iberia are considered to behave as two semi infinite elastic plates the evolution through time of the sedimentary thicknesses is explained by the deflections of these two plates induced not only by the topographic load of the pyrenees but also by additional forces 10 12 n m that may have their origin in the formation of a cold lithospheric root during the shortening a series of calculations is presented for an approximately north south profile across the aquitaine basin the pyrenees and the ebro basin a good fit for the shape of the basins and the gravity anomalies was obtained with flexural rigidities of 1 5 10 23 nm for the northern plate and the outer part of the southern plate and 1 4 10 21 nm for the inner part of the southern plate

shelf edge delta regime as a predictor of deep water deposition abstract shelf edge delta depositional style and particularly the presence of river dominated shelf edge deltas is a reliable indicator of deep water sand delivery as documented by a dataset of some 29 shelf margin clinoforms shelf edge delta regime defined as the sum of the effects of fluvial tidal wave and other oceanographic currents impacting deltas as they arrive at the shelf edge is a key predictor for likelihood of sand transport off the shelf edge to deep water conventional sequence stratigraphic concepts assume that delivery of sand to the deep water occurs primarily during falling and lowstand of relative sea level and that basinward transport is associated with shelf edge incision and sediment bypass recent analysis of outcrop and subsurface datasets has shown that sediment can also be transported to the deep water during rising and highstand of sea level provided sediment flux is high in addition some examples with documented shelf edge entrenchment associated with sea level fall did not deliver significant sand volumes to the deep water in contrast to the emphasis given to sea level and supply the role of the shelf edge delta itself and especially its process regime has received relatively little attention the data suggest that the behavior and process regime of the delta at the shelf edge is critical except where shelf width is minimal

properties of ancient deeply transformed man made soils cultural layers and their advances to classification by the example of early iron age sites in moscow region abstract the central part of european russia has been inhabited for several thousands of years its population being rather large in number by way of example we consider the dyakovo archeological culture dated to the early iron age numerous sites and settlements attributed to that culture are noted for the presence of typical anthrosols and technosols deeply transformed man made soils cultural layers in the course of the work we investigated thoroughly two soils related to settlements of the early iron age archeological excavations yielded numerous artifacts in situ this proves that the sites have been inhabited in the past though abandoned long since the cultural layers however have not been buried under later sediments far from it they stayed exposed and subjected to transformations by soil forming processes at present the sites are not in any use and are mostly overgrown with modern vegetation aside from the morphological description chemical analyses of the soils at the archeological sites have been performed a proportion of organic and inorganic matter total phosphorus ph being defined it should be noted that no typical zonal soils have been found at the sites in spite of the zonal vegetation overgrowing the areas instead there appeared soils of a peculiar kind showing specific properties when studying them the background soils were used as a reference so it seems that the time lapse between the early iron age and the present days a millennium and a half was insufficient for a complete transformation of the man made soils cultural layers it is rather difficult to choose a proper name of those soils the term technosol is hardly applicable as there are no human settlements there at present neither can the soils be considered as natural because they are radically different from the latter in characteristics and contain artificial materials in abundance

river dominated shelf edge deltas delivery of sand across the shelf break in the absence of slope incision shelf edge deltas record the potential magnitude of sediment delivery from shallow water shelf into deep water slope and basin floor and if un incised represent the main increment of shelf margin growth into the basin for that period the three dimensional complexity of shelf edge delta systems and along strike variability at the shelf edge in particular remains understudied the permian triassic kookfontein formation of the tanqua karoo basin south africa offers extensive three dimensional exposure 100 km2 and therefore a unique opportunity to evaluate shelf edge strata from an outcrop perspective analysis of stratal geometry and facies distribution from 52 measured and correlated stratigraphic sections show the following i in outer shelf areas parasequences are characterized by undeformed river dominated storm wave influenced delta mouth bar sandstones interbedded with packages showing evidence of syn depositional deformation the amount and intensity of soft sediment deformation increases significantly towards the shelf edge where slump units and debris flows sourced from collapsed mouth bar packages transport material down slope ii on the upper slope mouth bar and delta front sandstones pinch out within 2 km of the shelf break and most slump and debris flow units pinch out within 4 km of the shelf break iii further down the slope parasequences consist of finer grained turbidites characterized by interbedded thin tabular siltstones and sandstones the results highlight that river dominated shelf edge deltas transport large volumes of sand to the upper slope even when major shelf edge incisions are absent in this case transport to the upper slope through slumping debris flows and un channellized low density turbidites is distributed evenly along strike

earthquake and flood induced turbidites in the saguenay fjord quebec a holocene paleoseismicity record abstract a 38 m long piston core from the deep basin of the saguenay fjord quebec recorded rapidly deposited layers rdl interpreted to represent major floods and earthquakes over the past 7200 years high resolution physical magnetic and sedimentological analyses revealed at least 14 rdl generally with a sandy base and a light gray color interbedded with hemipelagic sediments digital x radiography and grain size analyses at

thick turbidite successions from supply dominated shelves during sea level highstand emphasis on the association between relative sea level lowstand and the formation of sandy deep water fans has tended to downplay the significance of high sediment supply and its potential to create deep water fans even during sea level highstands the lance fox hills lewis shelf margin in southern wyoming suggests that high supply was critical in causing the accretion of this moderately wide maastrichtian shelf margin at a minimum rate of 47 8 km m y and the generation of large sand rich fans during every shoreline regression across the shelf it is surprising that fans developed from shelf margin clinoforms that show systematically rising shelf edge trajectories proxy for rising relative sea level as well as from those that show flat trajectories stable to falling relative sea level however the latter producing more sediment bypass resulted in bigger and thicker fans whereas the former produced somewhat smaller and thinner fans we term the former highstand fans and suggest caution in using the lowstand model for high supply systems