fluvial response to paleo equatorial climate fluctuations during the late paleozoic ice age the maritimes basin of atlantic canada preserves a 12 km thick stratigraphic succession deposited within a low latitude predominantly continental setting during the late paleozoic this paper examines the utility of using such successions for paleoclimate analysis with specific reference to changes in fluvial style modern rivers in the subhumid and semiarid tropics preserve a suite of features that are distinct from those in humid and arid environments these features include an abundance of sedimentary structures formed under froude transcritical to supercritical flow conditions and the presence of in situ vegetation growing within the channel environment this fluvial style is indicative of prolonged low flow conditions punctuated by intense precipitation events in a strongly seasonal climatic setting fluvial channel bodies within the maritimes basin preserve a remarkably similar style compared with these modern systems suggesting that a subhumid strongly seasonal paleoclimate was the dominant imprint on parts of the preserved successions strongly seasonal deposits are concentrated within four discrete stratigraphic intervals e1 e4 ranging in duration from 2 to 6 m y these intervals are correlated across the entire basin and between basins characterized by markedly different tectonic regimes which suggests that a coherent regional climate signal is recorded intervals are separated by deposits characteristic of humid and arid river systems and the alternation between these different fluvial styles implies that several pronounced long term changes in precipitation and runoff regimes occurred during the carboniferous within the region furthermore these intervals broadly coincide with major periods of southern hemisphere glaciation which suggests that glaciation had a profound and controlling effect on paleotropical climate

horizontal lamination and the sequence of bed phases and stratification under upper flow regime conditions two forms of horizontal laminae have been produced under upper flow regime conditions in a flume by deposition on a plane bed and on low in phase waves upper plane bed laminae consist of approximately equal numbers of fining upward fu and coarsening upward cu textural laminae heavy minerals when present are typically within or form cu laminae in horizontal laminae formed under low in phase waves fu laminae may predominate and are significantly thicker than cu laminae heavy minerals are associated with the tops of some fu laminae and are absent from cu laminae deposits aggraded on plane beds and low in phase waves both display low angle 13 14 upstream grain imbrication upper plane bed horizontal laminae are attributed to the effects of the burst sweep cycle on local bedload transport bursts form fu laminae and sweeps form cu laminae some fu laminae in in phase wave deposits are thought to form with downstream migration of bed waves on which sand size decreases from trough to crest heavy minerals are concentrated in the tops of these fu laminae due to their enrichment on the crests of the migrating bed waves other fu and cu laminae in in phase wave deposits probably formed by the action of bursts and sweeps as on upper plane beds a sequence of bed phases and stratification formed under upper flow regime conditions is described based on the observations here combined with descriptions from the literature with increasing flow strength the gradual sequence of bed phases is 1 plane bed 2 low relief downstream migrating inphase waves increasing in amplitude and wavelength with increasing flow strength 3 stationary in phase waves 4 upstream migrating including breaking wave antidunes the sequence of stratification formed under these bed phases is 1 upper plane bed horizontal lamination 2 in phase wave horizontal lamination to in phase wave foreset cross laminae 3 in phase wave drape laminae 4 antidune backset cross laminae

stream driven high density gravelly traction carpets possible deposits in the trabeg conglomerate formation sw ireland and some theoretical considerations of their origin within high density flood flows a prominent mechanism of gravel transport and deposition is by stream driven high density traction carpet with a rheology similar to grain flow these gravel carpets are envisaged to form the basal portion of a bipartite high density flood flow decoupled from an overlying sand and silt laden turbulent flow several examples already documented in the literature are reviewed and an additional case from the lower old red sandstone of southwest ireland is presented two mechanisms of traction carpet initiation are discussed by rapid entrainment of gravel into suspension on rising stage followed by settling into the gravel traction carpet at peak and falling stage and by overconcentration of a normal low density bedload gravel entrainment suspension and traction carpet development are significantly easier if the flood water already carries a high concentration of sand and silt in suspension theoretical consideration further shows that gravelly traction carpets can be maintained in channels of relatively low gradient by the shear stress exerted by the high density sand bearing turbulent flood flow above this tangential shear stress is converted to dispersive pressure which aids buoyancy and quasi static grain to grain contacts in the support of the clasts within the gravel carpet the carpet is thought to have a quasi plastic rheology but behave much like a viscous fluid at high shear rates stream driven gravelly traction carpets are expected to produce sheet like units of clast to matrix supported conglomerate characterized by a parallel or an a p a i clast fabric these units may be ungraded normally or inversely graded depending on the rate of shear the viscosity of the flow and the celerity of deposition

a recent tectonic reorganization in the south central mediterranean abstract new geodetic data combined with seismicity geologic and geochemical information document a major tectonic reorganization in the central mediterranean around 0 8 0 5 ma when rapid trench migration and consequent tyrrhenian back arc extension which dominated the region s evolution since the tortonian 10 8 ma essentially stopped in response the african convergence in sicily was transferred to a back thrust in the southern tyrrhenian characterized by frequent m5 6 earthquakes in the last 20 years a diffuse transform boundary formed across northeastern sicily to connect the sicilian and calabrian plate boundaries causing opening of the messina straits home to large historical earthquakes and unusual volcanism in the aeolian island arc and the intraplate mount etna a divergence of the ionian region from the main part of africa with northeastward motions that reflect the joint influence of african push and hellenic slab pull and are transmitted to calabria and adria could explain motions observed in the sicily channel calabria and apulia as well as the high level of southeastern sicilian seismic activity

broadband waveform inversion of moderate earthquakes in the messina straits southern italy abstract we report the first application of the cut and paste cap method to compute earthquake focal mechanisms in the messina straits area by waveform inversion of pnl and surface wave segments this application of cap has furnished new knowledge about low magnitude earthquake mechanics that will be useful for improved understanding of the local geodynamics this is possible because the cap inversion technique can be applied to small earthquakes for which traditional moment tensor inversion methods are not appropriate and p onset focal mechanisms in the study area fail because of a lack of sufficient observations we estimate the focal mechanisms of 23 earthquakes with local magnitudes in the range of 3 4 occurring in the 2004 2008 time period and recorded by the broadband stations of the italian national seismic network and the mediterranean very broadband seismographic network mednet run by the istituto nazionale di geofisica e vulcanologia ingv the solutions show that normal faulting is the prevailing style of seismic deformation in the northern part of the study area while co existence of normal faulting and strike slip has been detected in the southern part in the whole area of investigation the t axes of focal mechanisms display a preferential northwest southeast direction of extension combined with the findings of previous investigations this improved database of focal mechanisms allows us to better detail the transitional area between the extensional domain related to subduction trench retreat southern calabria and the compressional one associated with continental collision western central sicily the observed spatial change of seismic deformation regime offers new data to current seismotectonic and seismic hazard investigations in the area of messina straits where a magnitude 7 2 earthquake caused more than 60 000 casualties on 28 december 1908

settlements of shallow foundations on sand a method to evaluate settlements and rotations of rigid shallow foundations on sand under the combined action of inclined and eccentric loads is presented experimental results obtained on a model strip foundation are shown first next a mathematical model is formulated which is based on the hypotheses that a the foundation and the soil can be considered as a macro element for which the loadings act as generalized stress variables while the displacements and rotation of the foundation are the corresponding generalized strain variables and b the constitutive law of the macro element that is the relationship between generalized stress and strain rates is rigid plastic strain hardening with a non associated flow rule constitutive functions and parameters are determined by means of simple calibration tests predictions of the theory are then compared with experimental results in tests where loadings vary in a complex way up to foundation failure it is shown that experimental evidence is well matched

flash flood sediments and ichnofacies of the late pleistocene homeb silts kuiseb river namibia abstract the homeb silt formation consists of eroded remnants of fine grained alluvium that were deposited within the kuiseb river valley in southern namibia during the late pleistocene in holocene times the river deeply incised its valley fill leaving steep walled castles of relict alluvium the homeb silts this study is based on the 25 m thick type exposure of homeb silts at homeb and describes flash flood sediments that were colonised by successive generations of opportunistic arthropods the stacked flood units each comprise a massive tabular siltstone bed overlain by a narrower interval of rapidly alternating sandstone and siltstone with claystone veneers these flood units are interpreted as having accumulated under semi arid climatic conditions by episodic back flooding of the kuiseb river into embayments and tributary mouths soon after deposition as the floodwaters subsided the sediment was colonised by burrowing sediment ingesting organisms mostly arthropods that produced a taenidium ichnofacies after the floodwaters had drained the exposed sediment was colonised by grasses and burrowed by terrestrial arthropods probably ants and termites resulting in an overprint of termitichnus ichnofacies with associated pelletal chambers thirteen horizons of rhizocretions and root tubules occur toward the top of the succession and indicate a gradual reduction in the frequency of flooding these immature calcic palaeosols suggest that the climate in the central namib desert 20 000 years ago was semi arid being wetter and more seasonal than the hyperarid conditions that prevail today

crayfish burrows from the latest cretaceous lower cantwell formation denali national park alaska their morphology and paleoclimatic significance abstract latest cretaceous strata of the lower cantwell formation denali national park central alaska range contain an abundance of megafloral remains and invertebrate and vertebrate trace fossils though dominated by herbivorous dinosaur footprints the abundance and diversity of fossil bird tracks are unique we present newly discovered crayfish burrows from several areas along a 50 km transect with denali national park most crayfish burrows from the lower cantwell formation are preserved only in cross section and range from approximately 5 10 cm in diameter where preserved in full relief and terminations present burrow depth is generally the cantwell formation fills the cantwell basin a 135 km long and up to 35 km wide east west trending basin bracketed by the hines creek fault to the north and the mckinley fault to the south basin fill comprises up to 4000 m of continental deposits interpreted as braided rivers alluvial fans floodplains swamps and ponds crayfish burrows provide evidence of water table level soil moisture fluctuations as well as insight into mean annual temperatures at the time of deposition of the lower cantwell formation a late cretaceous high latitude paleoecosystem despite a relatively high latitudinal setting 71 n paleolatitude the late cretaceous i e campanian maastrichtian mean annual temperature based on the distribution of similar present day crayfish burrows was more like that of southernmost ontario canada where the northernmost burrowing crayfish are found today the burrow depth suggests 1 no permafrost was present and 2 the phreatic zone was 30 50 cm below the paleo ground surface based on the presence of these crayfish burrows the paleoclimate is interpreted as humid continental koppen scheme with average summer high temperatures between 25 c and 28 c and average winter low temperatures between 6 c and 0 c these estimates compare somewhat favorably with previous clamp estimates of a warm monthly mean temperature of 17 08 1 6 c and a cold monthly mean temperature of 2 31 1 9 c

origin of crude oils in the jinhu depression of north jiangsu south yellow sea basin eastern china abstract the chemical compositions of 20 crude oils and the extracts of potential source rocks from the jinhu depression of the north jiangsu south yellow sea basin eastern china were studied in detail by geochemical methods in order to understand their genetic relationship the oil samples were collected from the major producing fields in the western slope ws and the biandong yangjiaba minqiao uplift belt bmy the rock samples studied selected after rock eval pyrolysis screening of a large suite of samples consist of 20 shale samples in the e 2 f 2 member of the paleocene funing formation from the oilfield areas ws and bmy and the sanhe sag all within the jinhu depression geochemical characteristics indicate only one single family of oils a number of biomarker features support deposition of the source rocks for these oils under conditions of enhanced salinity stratified water columns a wide thermal maturity range for the oils as indicated by sterane isomerization ratios was not substantiated by other maturity parameters the genetic relationships between the oils and the e 2 f 2 member of the paleocene funing formation present in the deeper parts of the sanhe and longgang sags were suggested using a wide range of molecular parameters variation in the sterane concentrations in source rocks with different maturity suggests that migrational contamination and or in situ extractions of organic matter from caprocks or intra reservoir shales by mature oils could potentially produce oils with apparent immaturity at the molecular level secondary alteration e g biodegradation of oils in the reservoir could also have a similar effect on the bulk oil compositions although we do not discount the possible presence of minor amounts of immature oils exploration focus in the jinhu depression as well as many other rift basins in eastern china should be on mature oils derived from the deep source kitchens

upper holocene sea level changes in the west saronic gulf greece abstract along the peloponnesian coast of the saronic gulf and on the coast of aegina and poros islands submerged coastal geomorphological features related directly with submerged ancient coastal constructions indicate three distinct sea levels submerged tidal notches incised on the carbonate basement beachrocks formed in the intertidal zone and archaeological indicators such as the ancient harbour installations in kenchreai and epidaurus and on aegina island the extended coastal buildings and constructions in agios vlasis psifta and palaiokastro methana and vagionia on poros island are used to determine the age and magnitude of submersion and the extent of the upper holocene marine transgression by the correlation of geomorphological historical and archaeological indications three distinct sea levels were identified at 3 30 0 15 m 0 90 0 15 m and 0 55 0 05 m initial change in sea level occurred definitely after ad 400 100 the intermediate change is dated between ad 1586 and 1839 and the most recent change after 1839 sea transgression followed a long period of sea level stability which lasted at least 2200 years from the middle bronze age to the late roman period

palaeoecology of an early permian playa lake trace fossil assemblage from castle peak texas usa abstract the early permian choza formation of the clear fork group at castle peak in texas usa contains a diverse and remarkably abundant trace fossil assemblage comprising exquisitely preserved arthropod trackways diplichnites gouldi types a and b diplichnites isp a and b lithographus isp and cf kouphichnium isp striated trails cruziana problematica and isolated resting traces rusophycus carbonarius and r furcosus surface or shallow subsurface grazing trails or burrows gordia indianensis helminthoidichnites tenuis treptichnus isp a nodular trail and unilobate epichnial trails backfilled deposit feeding burrows planolites beverleyensis meniscate backfilled burrows taenidium barretti horizontal branching networks and tetrapod trackways dromopus palmatus erpetopus willistoni varanopus curvidactylus and cf amphisauropus isp trace fossils formed in and around the margins of a shallow ephemeral playa lake within an alluvial plain and provide evidence of temporary communities comprising arthropods most notably notostracan branchiopod crustaceans as well as euthycarcinoids myriapods insects and tetrapods including protorothyridid captorhinid and araeoscelid reptiles and rare amphibians periodic influxes of water into the alluvial plain filled various depressions creating temporary habitats and flourishes of life and activity the trace fossil assemblage is typical of the scoyenia ichnofacies and is similar to other assemblages from a range of different transitional subaqueous to subaerial settings indicating that the distribution of trace fossils is not inextricably linked to the depositional setting itself but rather to the environmental factors that arise such diverse trace fossil assemblages probably reflect relatively long lived ephemeral water bodies whereas more impoverished examples probably represent shorter lived ephemeral water bodies assemblages such as castle peak with abundant delicate arthropod trackways probably reflect low energy conditions conducive to the presence of an abundant vagile epifauna and the preservation of their trackways whereas assemblages with open vertical burrows tend to lack arthropod trackways and probably reflect higher energy conditions trace fossil assemblages dominated by arthropod and tetrapod trackways may represent fleeting preservation windows following sheetfloods on floodplains

a new view of italian seismicity using 20 years of instrumental recordings in this paper we show the seismicity of the past 20 years that occurred in italy and surrounding regions hypocentral locations have been obtained by using p and s wave arrival times from the ingv national and several regional permanent seismic networks more than 48 000 events selected from an original data set of about 99 780 are used to reconstruct the most complete seismic picture of the italian region so far the seismicity distribution allows inference on seismotectonics of this complex region of subduction versus continental collision our results clearly reveal the geometry of the adria and the ionian subduction and a continuous normal fault belt in the upper crust following the apennines mountain range the depth of the seismogenic layer is computed from the cut off of seismicity at depth and shows large variations along and across the seismic active regions earthquakes are generated by the different velocity of slab retreat and the subsequent asthenospheric upwelling d 2004 elsevier b v all rights reserved

evidence of relative sea level rise along the coasts of central apulia italy during the late holocene via maritime archaeological indicators abstract we investigated archaeological sites located along the coasts of central apulia italy to estimate the relative sea level changes which have occurred in this region since the bronze age and test the most recent model of predicted sea level for this region surveys focused on six sites located on both the adriatic and ionian coasts of apulia at the feet of the carbonatic murge plateau a tectonically stable zone as of the last 125 ka the sites present the remains of ancient settlements ranging from the bronze age circa ii millennium bc to the messapian and magna grecia age c 2 5 ka bp the roman c 2 ka bp and middle ages c 1 ka bp the archaeological sea level markers investigated in these sites provided new insight into the history of the relative sea level changes which have occurred in this region during the last c 3 3 ka bp data from 17 archaeological settlements from the above mentioned sites placed above or below the present sea level were analyzed the intervening relative sea level changes successive to their construction were estimated via the submergence of the functional elevations of significant architectural features related to the mean sea level at the time during which the settlements were functioning the r s l changes were estimated using detailed topographic surveys tide analyses and or hydrodynamic equations although not all archaeological markers allowed univocal interpretations r s l rise at about 2 25 0 20 m as of the bronze age and at least 0 90 0 20 m in the last 2 0 1 5 ka was estimated a comparison between the elevation of the marker and two different predicted sea level models seems to confirm a tectonic stability of the investigated region in the last c 3 3 ka bp

high energy ephemeral stream deltas an example from the upper silurian holmestrand formation of the oslo region norway abstract the late orogenic deposits of the upper silurian holmestrand formation of the oslo region norway comprises sharply alternating ephemeral stream and sandy beach face deposits the formation is divided into three units reflecting the down slope change on an extensive ephemeral stream delta system the lower unit of the formation comprises ephemeral stream sediments as stacked sheet sandstone bodies deposited on a broad coastal floodplain each sheet is bounded by a lower intraclast strewn scoured surface overlain by massive horizontally stratified low angle and trough cross bedded sandstones in the medial and upper units of the formation the ephemeral stream sediments alternate with beach face deposits forming ephemeral stream deltas the ephemeral stream deltas are marked by intraclast strewn scoured surfaces and dominated by trough cross bedded sandstones they may contain escapement burrows marine bioturbation and wave working of the delta surfaces the beach face deposits are composed of alternating irregular horizontally stratified sandstones with current and wave ripple cross lamination and tabular cross bedded sandstones deposition took place in a coastal non to micro tidal shallow water environment influenced by longshore currents and low palaeo wave energy seven ichnotaxa are recognized and support the sedimentary record of a transitional environment between a broad coastal floodplain and a shallow marine environment the presence of calcretes indicate an arid to semi arid palaeo climate

paleogene sediment provenance and paleogeographic reconstruction of the south yellow sea basin east china constraints from detrital zircon u pb geochronology and heavy mineral assemblages abstract this study presents new zircon u pb geochronological and heavy mineral assembly data from paleogene rocks to constrain the provenance and paleogeographic evolution of the south yellow sea basin sysb east china heavy minerals are mainly ilmenite garnet epidote zircon and pyrite detrital zircon ages from the paleocene funing to eocene sanduo formations can be grouped into five major populations 100 300 ma 400 500 ma 600 900 ma 1700 2100 ma and 2300 2700 ma paleocene funing sediments mainly contain zircons of 220 ma 760 ma 1850 ma and 2500 ma consistent with zircons from the daibie sulu orogen the south china craton and the north china craton lower eocene dainan sediments show different detrital zircon ages and heavy mineral assemblages indicating a change in sediment sources the daibie sulu orogen served as a major source for the north depression sediments of the southern segment of the south depression were derived mainly from the daibie sulu orogen and the north china craton from the west while sediments of the northern segment of the south depression received a southwestward supply from the central uplift with detrital zircon peak ages of 440 ma detrital zircon age spectra of sanduo samples resemble those of dainan samples with peaks at 120 ma 220 ma 440 ma 800 ma 1850 ma and 2500 ma suggesting that they share common sources the results allow the reconstruction of an updated paleogeographic model for the paleogene of the south yellow sea basin

skolithos linearis haldeman 1840 at its early cambrian type locality chickies rock pennsylvania analysis and designation of a neotype abstract the trace fossil skolithos with its simple vertical to very slightly inclined tubular form is widely recognized and globally distributed in early cambrian to holocene strata representing deep sea to continental paleoenvironments the type species skolithos linearis was first described in 1840 by samuel s haldeman based on his observations of early cambrian quartzite at chickies rock a well known landmark on the east bank of the susquehanna river in pennsylvania the original description was meager no illustrations were published no holotype was established and no specimens directly associated with haldeman are known to exist today a neoholotype proposed by howell 1943 is invalid as it does not conform to requirements of the international code of zoological nomenclature as a result the iconic ichnogenus skolithos is inadequately characterized and some of the numerous ichnospecies that have subsequently been named are not unequivocally assignable to it in order to stabilize this important ichnogenus and to provide a basis for the taxonomic revision it urgently requires we have studied s linearis at its type locality our new material is described and illustrated here and we have designated a neotype accessioned by the u s national museum of natural history smithsonian institution the stratigraphy and regional geologic setting of chickies rock the sedimentology and environment of deposition of cross bedded quartzite with abundant s linearis constituting classic pipe rock and the structural deformation of this fabric are reviewed given the simple morphology of skolithos disparate organisms in several phyla have been proposed as its maker we concur in the general view that cambrian trace fossils assigned to s linearis were most probably made by burrowing phoronids or polychaete annelids the global abundance of largely monospecific pipe rock in analogous cambro ordovician settings is recognized as a characteristic feature of the ecology of shallow marine environments of that time the stage has now been set for a thorough re evaluation of all existing ichnospecies assigned and related to the ichnogenus skolithos

combined loading of spudcan foundations on clay laboratory tests recent research has shown that work hardening plasticity theory provides a suitable framework for interpreting and predicting the load displacement behaviour of rigid shallow foundations under combined vertical moment and horizontal loading most previous work has however been restricted to footings on granular soils this paper describes a series of laboratory tests conducted at unit gravity using a small circular footing and specimens of reconstituted kaolin the results indicate that work hardening plasticity concepts can also be applied to the modelling of shallow foundation behaviour on undrained clay the footing shape chosen for the experiments is representative of the spudcan foundations which support the legs of jack up drilling platforms a novel testing apparatus allows independent control of the vertical rotational and horizontal footing displacements within a single vertical plane tests conducted at constant vertical penetration are used to investigate the shape and size of the combine

comments on the paper reconnaissance of upper jurassic morrison formation ichnofossils rocky mountain region usa paleoenvironmental stratigraphic and paleoclimatic significance of terrestrial and freshwater ichnocoenoses by stephen t hasiotis

diagenetic effects on porosity permeability relationships in red beds of the lower triassic bunter sandstone formation in the north german basin abstract carbonate and anhydrite cement clay clasts and inter granular clay are the main components that reduce reservoir quality in the studied bunter sandstone formation the impacts of these parameters on porosity and permeability are determined by combining petrographic mineral quantification with conventional core analysis of samples from the danish part of the north german basin the depositional environments are considered because they largely control the distribution of cements clays and grain sizes the lateral variability of depositional environments is defined by the position in the basin and the proximity to the source areas the stratigraphic distribution of depositional environments is related both to local topography and to climate because high aridity promoted aeolian deposition the bunter sandstone formation has high porosity and permeability in most of the sandstone intervals in the northern north german basin the reservoir quality is good as long as the cements and clays are present as confined bodies that leave the remaining pore spaces available for flow in contrast inter granular clay and pervasive cementation hinder virtually all flow through the sandstone the ephemeral fluvial deposits have an average porosity and permeability of 20 3 and 810 md respectively and the values are 24 6 and 807 md for the aeolian sandstones excluding the unconsolidated aeolian sands which presumably have higher porosity and permeability the aeolian sandstones of the volpriehausen member have very good reservoir quality since they have a thickness of about 25 m are laterally continuous are largely clay free and the cement occurs in small amounts the sandstones of the solling member consist mainly of ephemeral fluvial deposits which generally have good reservoir quality however some intervals have high contents of inter granular clays or pervasive carbonate anhydrite or halite cement and these components reduce the permeability significantly the lateral distribution of the ephemeral fluvial sandstones is variable and therefore difficult to predict when planning a geothermal exploration well thus the volpriehausen member is the preferred target

do red beds indicate paleoclimatic conditions a permian case study abstract terrestrial red beds have long been interpreted as desert deposits by comparison with modern red deserts more recently red beds have been interpreted as evidence of seasonally dry conditions and a permo triassic pangean monsoon red beds of cala viola sardinia are identified as paleosols and used to reconstruct late permian paleoclimatic conditions reconstruction of paleoenvironmental conditions based on the paleosols of the cala viola indicates warm humid conditions with no evidence of dry conditions as in a desert or of extreme seasonality as in a monsoon instead it is suggested that the red color of the paleosols is a result of former good drainage and that red color in general does not indicate specific paleoclimatic conditions

luminescence chronology of pleistocene marine terraces of capo vaticano peninsula calabria southern italy abstract quaternary terrace deposits exposed on the capo vaticano peninsula calabria southern italy have been investigated in order to obtain new osl age estimates six samples were collected from unconsolidated sediments associated with the major marine terraces these form a flight of seven distinct levels distributed between about 600 m and 30 m of altitude the samples were analysed by optically stimulated luminescence osl technique the obtained results provided reliable age estimates showing numerical ages ranging between 214 25 ka and 62 6 ka age determinations combined with geological and morphological information provide new constraints for correlating the distinct orders of marine terraces with the last seven interglacial stages of the eustatic curve this correlation indicates that in the middle late pleistocene this portion of the southern calabrian arc was affected by a vigorous uplift characterized by rates up to 2 mm y

origin of red beds in the paleoproterozoic franceville basin gabon and implications for sandstone hosted uranium mineralization red beds are extensively used as evidence for an oxygenated atmosphere in the paleoproterozoic red beds in the unmetamorphosed ca 2 15 ga fa formation of the franceville basin gabon were geochemically petrographically and mineralogically characterized to constrain the process of their formation and their relationship to atmospheric oxygenation in the early paleoproterozoic petrographic observations indicate that ferric oxides are dispersed in clay filling intergranular pores and along platy cleavage in altered phyllosilicates grain coating hematite is generally rare to absent in most samples suggesting hematite precipitation after sediment deposition and during burial diagenesis textures and geochemical data suggest that iron was likely sourced internally by alteration of iron bearing minerals such as biotite and chlorite in sediments and redistributed in rocks during late diagenesis positive correlation between fe mg ratio and 56fe values of bulk samples suggests mixing relationship with end members being authigenic hematite and iron bearing silicates biotite and chlorite the lack of relationship between fe3 fet ratios and iron isotope compositions suggest that the isotopically heavy iron oxide was already present in the sediments during early diagenesis and was incorporated into green reduced facies that likely replaced red facies during diagenesis and burial large range of 56fe values extending towards positive values up to 1 permil is similar to that observed in archean and paleoproterozoic iron formations or modern groundwater derived fe oxyhydroxides suggesting partial oxidation of fe under mildly oxidizing conditions during early diagenesis

pattern and rate of post 20 ka vertical tectonic motion around the capo vaticano promontory w calabria italy based on offshore geomorphological indicators abstract the magnitude and rate of late pleistocene holocene vertical tectonic movements offshore of the capo vaticano promontory western calabria southern italy have been measured on the basis of the present day depth variations of the edges of submerged depositional terraces and associated abrasion platforms that formed below the storm wave base during the sea level stillstand of the last glacial maximum lgm these depositional features represented by submerged prograding wedges and an associated terrace shaped upper boundary have been identified in high resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory and are referred to in this study as lowstand infralittoral prograding wedges lipws our new data and methods provide evidence that lipws can be used as geomorphological indicators of vertical movements in offshore settings with well controlled uncertainty removal of the non tectonic component of vertical changes using an ice volume equivalent eustatic sea level compilation indicates 11 3 2 m of uplift and 25 3 2 m of subsidence from southwest to northeast along the promontory over a distance of 22 km during the post lgm the resulting uplift and subsidence rates including both regional and local components for the last 20 350 1 35 years are 0 54 0 2 mm y and 1 23 0 25 mm y respectively these results are consistent with longer term estimates based on uplifted 215 82 ka old coastal terraces and late holocene shorelines this integration of offshore and coastal markers indicates a pattern of vertical movements characterized by a marked asymmetry associated with a northeast down tilt of the capo vaticano promontory the calculated tilt rate increases by one order of magnitude during the post lgm in respect to the time interval from 215 to 82 bp displacement associated with the nw se striking normal fault that bound the capo vaticano promontory to the gioia tauro basin ended in the pleistocene and thus does not contribute to the tilt of the promontory at least during the last 215 ka

new insights on the relative sea level change during holocene along the coasts of tunisia and western libya from archaeological and geomorphological markers new data of sea level changes for the mediterranean region along the coasts of northern africa are presented data are inferred from archaeological sites of punic roman age located along the coast of tunisia between tunis and jerba island and along the western coast of libya between sabratha and leptis magna data are based on precise measures of presently submerged archaeological markers that are good indicators of past sea level elevation nineteen selected archaeological sites were studied in tunisia and four in libya all aged between 2 0 and 1 5 ka bp the functional elevations of significant archaeological markers were measured with respect to the sea level at the time of measurements applying corrections for tide and atmospheric pressure values the functional elevations of specific architectural parts of the sites were interpreted related to sea level at the time of their construction providing data on the relative changes between land and sea observations were compared against sea level change predictions derived from the glacio hydro isostatic model associated with the last glacial cycle the results indicate that local relative sea level change along the coast of tunisia and libya has increased 0 2 0 5 m since the last 2 ka besides minor vertical tectonic movements of the land the observed changes are produced by eustatic and glacio hydro isostatic variations acting in the mediterranean basin since the end of the last glacial maximum

submarine depositional terraces in the tyrrhenian sea as a proxy for paleo sea level reconstruction problems and perspective abstract in the last decade great effort was put in the study of relative sea level changes on mediterranean coastlines through the integration of geophysical modelling and proxy data of paleo shorelines in this paper we show potential and limitations of using additional marine geomorphic sedimentary markers for earlier and lower sea levels these markers are submarine depositional terraces sdts i e deposits formed by a set of small prograding sedimentary wedges having a terraced shape and found at variable shallow water depths mainly the first 150 m on continental and insular shelves in the tyrrhenian sea the shallowest terraces near shore have their edges at depths between 10 m and 30 m approximating the modern local storm wave base level their formation is thought to be associated with the modern sea level highstand and thus can be used as the modern analogue for deeper terraces formed in the past when the sea level was on the middle and outer shelf mid shelf terraces have their edges at variable depths between 40 m and 90 m and probably formed during the last sea level rise they show a patchy spatial distribution and a large variability in their internal structure so that they are not suitable for correlation on a regional scale shelf edge terraces have their edges at depths between 120 m and 170 m which is close or deeper than the last glacial maximum lgm sea level stand they show a remarkable lateral continuity and a prograding internal structure similar to those at shallower depth and thus represent a proxy for the sea level position at around 20 ka however the position of sdts edges is not a direct measure of paleo sea level positions because their depth depends on a complex interplay of several factors such as the base of the storm wave and its variation in response to coastal physiography as well as the occurrence of subsequent erosional or depositional processes depending on the geophysical and mapping methods used to determine their depth the associated error range can also differ based on the analysis of these complexities and a wide range of physiographic settings of the tyrrhenian sea we discuss these error ranges in order to assess potential and limitation of the sdt for analyses of vertical mobility of an area

numerical modelling of the september 8 1905 calabrian southern italy tsunami summary this paper presents a study of the tsunami following the disastrous earthquake that occurred on the 8th of september 1905 in calabria southern italy the shock caused devastation in many towns and villages leading to more than 500 victims according to coeval sources the tsunami was not catastrophic but was large enough to inundate low lying lands in several coastal segments and to affect boats no specific study was ever devoted to this tsunami in the literature our analysis is carried out by means of numerical modelling and aims at filling this gap since the source fault of the earthquake has not yet been identified we study three tsunamis produced by likely potential sources according to macroseismic data and the seismotectonic knowledge of the region namely the capo vaticano cv fault the vibo valentia vv fault and the lamezia la fault we compute tsunami waves under the hypotheses that the sea floor deformation is caused by a shear double couple dislocation taking place over a rectangular fault and that sea waves propagate according to the shallow water approximation the three tsunamis cause either a pure initial depression vv and la or a predominant initial depression cv of the sea surface in the gulf of st eufemia one very relevant finding is that tsunami energy is trapped within a narrow channel along the calabrian coast to the north of the source with the consequence that wave amplitudes computed here are much larger than the values expected in the case of an ordinary energy decay law with distance energy trapping along southern coastal segments is less efficient only a small fraction of tsunami energy penetrates the straits of messina to the south propagation to the west is affected by the aeolian islands that produce a quasi shadow zone on the side opposite to the tsunami impact the la tsunami is found to be too weak to be compatible with observations a sensitivity analysis concerning some parameters of the faults namely length width and slip magnitude has been performed in order to explore their influence on the tsunami features the main result of this paper is that we cannot discriminate between the cv and vv sources both are in agreement with some historical observations whilst they do not match others we believe that a better tuning of the source mechanism over these faults can improve the agreement between model computations and historical observations

dendropoma lower intertidal reef formations and their palaeoclimatological significance nw sicily abstract most carbonate rocky shores of nw sicily are marked by a coalescence of shells of the gastropod dendropoma in a construction that is variably developed as a response to wave impact here we review all the available information on these constructions and find that the fossil reefs are reliable sea level indicators the thickness of the reef samples never exceeds 30 40 cm below sea level whereas all 14 c dates fall within a range of few centuries some small fragments ejected by violent sea storms date back to 2500 years cal bp no samples older than 6200 years cal bp have been detected so far the present distribution of mediterranean vermetid platforms should result from a northward migration related to the long term effect of the holocene sea surface temperature sst warming some consideration on the morphology of the reefs and the comparison with the available data point out that dendropoma reefs are excellent biological indicators of sea level fluctuations especially when detected and sampled in tectonically stable areas as those in nw sicily

basin scale changes in floodplain paleosols implications for interpreting alluvial architecture abstract floodplain paleosols in time equivalent strata of the willwood for mation differ in terms of paleodrainage and degree of pedogenic development ancient soils were more poorly drained and more strongly developed in one area compared to a second area about 45 km away this difference in drainage is attributed to parent material the more poorly drained paleosols formed in an area with less permeable clay rich floodplain deposits in the stratigraphic interval that accumulated more slowly paleosols are more strongly developed less numerous and thicker than in the more rapidly accumulating stratigraphic interval these differences are attributed not only to different sediment accumulation rates which are commonly considered to control the degree of ped ogenic development but also to differences in avulsion frequency a simple model is offered to show how paleosols change with varying basin subsidence rates and the relationship between avulsion frequency and accumulation rate when avulsion frequency increases more rapidly than sediment accumulation rate an increase in subsidence rate causes strongly developed paleosols to be overlain by a stratigraphic interval with paleosols that are less well developed thinner and more densely spaced when avulsion frequency is not related to accumulation rate as early models of alluvial architecture assumed an increase in subsidence rate produces a stratigraphic section in which strongly developed paleosols are overlain by paleosols that are less well developed thicker and more widely spaced study of the thickness and degree of development of floodplain paleosols can be used together with more traditional studies of alluvial architecture to provide a clearer understanding of the factors that influenced the stratigraphic architecture in a particular alluvial basin

modeling long term ground deformation due to the cooling of a magma chamber case of basiluzzo island aeolian islands italy 1 we estimate the long term vertical deformation of basiluzzo island located in the volcanic arc of the aeolian islands italy by inferring the subsidence of a roman age submerged wharf dated 2000 50 years ago we model the crustal deformation that produced this displacement as a cooling magma chamber emplaced during the formation of the island this is the first attempt to model crustal deformation using the subsidence of a submerged archaeological structure nowadays the top of the wharf which can be considered an unconventional leveling benchmark is located near punta levante at an average depth of 3 20 0 10 m below actual sea level and it is still in good conservation its present location is due to combined effect of sea level rise and volcanic and tectonic activity that occurred since it was built taking into account the architectural features of the wharf and that the mean sea level rise of the mediterranean sea has been estimated as 0 45 m during the last 2000 years flemming and webb 1986 we estimate a total subsidence of 3 75 0 10 m at a rate of about 1 87 mm yr 1 anzidei et al 2002 we propose a possible mechanism for the long term subsidence which occurred on a timescale of thousands of years by considering the earth s crust as a maxwell body we assume that the magmatic source is located directly beneath basiluzzo dome and underwent progressive solidification and subsequent volume reduction since its emplacement 50 000 years ago

trace fossils from carboniferous floodplain deposits in western argentina implications for ichnofacies models of continental environments abstract floodplain deposits from the carboniferous tupe formation of western argentina contain a low diversity ichnofauna of invertebrates and plants the assemblage consists of archaeonassa fossulata didymaulichnus lyelli helminthoidichnites tenuis palaeophycus tubularis planolites isp and root traces this ichnofauna is characterized by the dominance of very simple forms superficial or very shallow trace fossils combination of locomotion grazing and dwelling structures and production by arthropods and vermiform organisms primary sedimentary fabrics are disturbed only by plant trace fossils while animal trace fossils are mostly restricted to bedding surfaces resulting in the virtual absence of bioturbation the poorly defined morphology of the ichnofossils and the absence of backfilled striated trace fossils and structures indicative of subaerial exposure suggest subaqueous production the envisaged depositional environment is a freshwater body developed in a floodplain and overfilled by overbank deposits a review of floodplain ichnofaunas documented from the stratigraphic record indicates that two recurrent assemblages may be recognized the first assemblage is characterized by low to rarely moderate diversity of invertebrate trace fossils moderate to high diversity of vertebrate structures and common presence of meniscate backfilled structures bilobate trace fossils with scratch marks arthropod trackways and tetrapod trackways it is regarded as an example of the scoyenia ichnofacies developed in desiccated floodplains the second type of floodplain assemblage illustrated by the example documented in this paper is characterized by grazing trails locomotion trails and dwelling burrows low to rarely moderate ichnodiversity simple trace fossils and superficial to very shallow structures although formed in floodplain environments also this type of assemblage is remarkably different from the scoyenia ichnofacies it is here regarded as an example of the mermia ichnofacies basic features of these ichnofaunas reflect subaqueous production of the assemblage the lower ichnodiversity of these floodplain assemblages in comparison with their equivalents from lacustrine basins is probably an expression of the less stable conditions and temporary nature of floodplain water bodies our study supports the view that ichnofacies are not indicators of sedimentary environments but reflect sets of environmental factors

organic geochemistry of the lacustrine shales from the cretaceous taizhou formation in the gaoyou sag northern jiangsu basin abstract the shale from the cretaceous taizhou formation is an important source rock in the gaoyou sag northern jiangsu basin fifty three shale core samples analyzed for total organic carbon toc and rock eval pyrolysis analyses were used to evaluate the geochemistry of this shale twenty one samples of them were analyzed using solvent extraction extract fractionation gas chromatography mass spectrometer gc ms of the saturated fraction and organic petrology analyses based on the test results the shale of the taizhou formation contains mainly type ii iii organic matter and is chiefly oil prone and oil gas prone as a fair to good oil source rock with a small quantity of gas source rock vitrinite reflectance rock eval pyrolysis and biomarker suggest that in this sag the shale of the taizhou formation is mainly in the early mature stage and within the oil window so the shale generates chiefly liquid oil the gaoyou sag is an oil generating sag the saturated fraction and biomarker composition of the shale provide evidence that the taizhou formation shale was formed mainly in a reductive sedimentary environment with anoxic fresh to low salinity water the organic matter came chiefly from plankton and partly from land plants and bacterial organisms

millstone coastal quarries of the mediterranean a new class of sea level indicator abstract the coasts of italy still preserve several remnants of coastal quarries built in antiquity that now provide insights into the intervening sea level changes occurred during the last millennia in this paper we show and discuss a new class of sea level indicator consisting of millstones carved along the rocky coast of southern italy since 2500 bp that are currently submerged they were extracted from beachrocks sandstones or similar sedimentary rocks easier for carving by ancient carving tools our study focuses on 10 coastal sites located at capo d orlando avola and letojanni in sicily soverato tropea and capo dell armi in calabria castellabate palinuro and scario in campania and polignano san vito in apulia unfortunately only limited archaeological information is available for these anthropic structures scario one of these millstone quarries discussed here has been dated through independent archaeological remains allowing us to restrict the exploitation age to the end of xvii century present day elevations of these coastal sites were obtained through geo archaeological surveys calibrated using the nearest tidal stations together with geomorphological and tectonic interpretations data were compared against the latest sea level predictions based on glacio hydro isostatic models our results allow proposal of the age range of these millstone quarries and to estimate the intervening relative sea level changes since the time when they were carved

trace fossils from marginal lacustrine deposits of the cretaceous jinju formation southern coast of korea abstract trace fossils from the cretaceous jinju formation of the south coast of korea occur in interbedded medium to fine grained sandstone of a moderate energy lake shoreface and mudstone shales of a periodically exposed low energy shallow lake and interfingerings of both of the above the trace fossils are represented by beaconites antarcticus beaconites coronus cochlichnus anguineus diplichnites octopodichnus cf didactylus diplichnites type a diplichnites isp helminthopsis hieroglyphica palaeophycus sulcatus palaeophycus tubularis planolites annularis planolites beverleyensis protovirgularia dichotoma skolithos magnus taenidium barretti and sauropod tracks the diplichnites specimens are among the first arthropod trackways recorded from the cretaceous two of the four trackway bearing ichnocoenoses present in the study area are considered representative of composite ichnofacies sinusoidal burrows or trails and simple irregular interface burrows or trails probably formed in wet possibly submerged soupground softground conditions in low or medium energy lake margins and represent the mermia ichnofacies trackways and meniscate burrows probably formed on the subsequently subaerially exposed lake margins following lake regression and represent an overprinting by the scoyenia ichnofacies the other two trackway bearing ichnocoenoses are from the scoyenia ichnofacies alone

facies architecture and palaeoenvironmental implications of the upper cretaceous santonian csehbanya formation at the iharkut vertebrate locality bakony mountains northwestern hungary abstract the csehbanya formation santonian exposed in the iharkut open pit bakony mountains hungary is made up of a cyclic alternation of conglomerate sandstone and variegated siltstone and clay deposited in a fluviolacustrine environment as a result of continuous excavation since 2002 it has yielded rich and diverse continental vertebrate and plant assemblages a facies and architectural analysis of the csehbanya formation at this location identified four main lithofacies associations with eight subtypes consisting of 1 lenticular sandstones representing river channels 2 conglomerates with sandstone coarse grained likewise representing channel deposits 3 heterolithic channel fill high density flash flow deposits 4 splay sandstones produced by crevasse splays 5 dark sandy siltstone small scale stagnant pool deposits with high organic content 6 greenish grey claystone deposits of shallow lakes and ponds 7 reddish moderately drained paleosols and 8 yellowish mottled hydromorphic paleosols the sedimentological investigations revealed that the terrestrial deposits exposed by the iharkut open pit were formed in an anastomosing fluvial system because i the alluvial architecture is characterized by large proportion of overbank deposits encasing the channel sandstone bodies ii the ribbon shaped sandstone bodies are dominant iii cross bedding and lateral accretion are almost completely absent in the channel fill deposits and iv the sandstone bodies are clearly isolated from each other embedded in floodplain sediments suggesting multiple co existing channels the most important vertebrate fossil site sz 6 was examined in special detail because it shows peculiar lithological features the layers richest in fossils unit 1 of sz 6 site are interpreted as a lag deposit formed during an episodic high density flash flood event representing a relatively short time interval i e probably within a single rainy season

avulsion deposits in lower eocene alluvial rocks bighorn basin wyoming abstract eocene alluvial rocks in the northern bighorn basin can be subdivided into three major kinds fine grained deposits on which cumulative paleosols developed lithologically heterogeneous packages associated with immature paleosols and major sheet sandstone bodies the heterogeneous packages which alternate vertically with the cumulative paleosols are dominated by fine grained deposits and also contain ribbon sandstone bodies and thin 1 m sheet sandstone bodies most ribbon sandstones are less than 3 m thick and are more common in the middle and upper parts of the packages cut and fill deposits with fine grained fills are locally important because the lithologic packages are readily apparent in the field because of the immature or simple paleosols developed on the fine grain d facies they are referred to as simple paleosol packages the major sheet sandstones were deposited by meandering trunk rivers and locally overlie and truncate the other deposits contrary to classical models of meandering streams only a portion of the fine grained rocks in the study area were deposited by overbank flooding of a trunk channel on the basis of their stratigraphic position and few ribbon sandstones the upper parts of some simple paleosol packages are interpreted as ancient levee deposits associated with a trunk channel farther from the trunk channel overbank floods deposited alluvium on which the cumulative paleosols formed the greater parts of the simple paleosol packages including their fine grained deposits were deposited rapidly during channel avulsion ribbon sandstone bodies represent ancient splay channels on the avulsion belt simple paleosol packages in the willwood formation support the contention of smith et al 1989 that n many meandering river systems a significant portion of the fine grained deposits were deposited as the trunk channel avulsed deposits that resemble the simple paleosol packages may provide a means of recognizing avulsion episodes in other alluvial sequences

approaching the seismogenic source of the calabria 8 september 1905 earthquake new geophysical geological and biochemical data from the s eufemia gulf s italy abstract recognizing the seismogenic source of major historical earthquakes particularly when these have occurred offshore is a long standing issue across the mediterranean sea and elsewhere the destructive earthquake m 7 that struck western calabria southern italy on the night of 8 september 1905 is one such case having various authors proposed a seismogenic source with apparently diverse hypotheses and without achieving a unique solution to gain novel insight into the crustal volume where the 1905 earthquake took place and to seek a more robust solution for the seismogenic source associated with this destructive event we carried out a well targeted multidisciplinary survey within the gulf of s eufemia se tyrrhenian sea collecting geophysical data oceanographic measurements and biological chemical and sedimentary samples we identified three main tectonic features affecting the sedimentary basin in the gulf of s eufemia 1 a ne sw striking ca 13 km long normal fault here named s eufemia fault 2 a wnw striking polyphased fault system and 3 a likely e w trending lineament among these the normal fault shows evidence of activity witnessed by the deformed recent sediments and by its seabed rupture along which locally fluid leakage occurs features in agreement with the anomalous distribution of prokaryotic abundance and biopolymeric c content resulted from the shallow sediment analyses the numerous seismogenic sources proposed in the literature during the past 15 yr make up a composite framework of this sector of western calabria that we tested against a the geological evidence from the newly acquired dataset and b the regional seismotectonic models such assessment allows us to propose the ne sw striking normal fault as the most probable candidate for the seismogenic source of the 1905 earthquake reappraising a major historical earthquake as the 1905 one enhances the seismotectonic picture of western calabria further understanding of the region and better constraining the location of the seismogenic source may be attained through integrated interpretation of our data together with a on land field evidence and b seismological modeling

sandy high energy flood sedimentation some criteria for recognition with an example from the devonian of s w england abstract many modern sand deposits resulting from episodic floods in semi arid zones are dominated by parallel laminations but parallel laminated sands are not a major feature in perennial streams single flood events may deposit over 1 5 m of parallel laminated sand hence ancient parallel laminated sand dominated alluvial deposits may be the product of ephemeral flows the trentishoe formation hangman sandstone group middle devonian of north devon consists in part of laterally extensive beds of parallel laminated fine grained red sandstones that build multistorey sand bodies individual beds are little more than 1 m thick but may extend laterally for hundreds of metres a vertical sequence of erosion surface sparse silt clasts parallel laminations silt drape is often found suggesting high flow stage deposition of plane bedded sand followed by a very rapid waning of flow with silt fallout in the final stages of the flood this sequence bears marked similarity to certain modern ephemeral flow sands

the italian cmt dataset from 1977 to the present abstract the ingv harvard european mediterranean regional centroid moment tensor rcmt catalog collects solutions routinely computed since 1997 for earthquakes with moderate magnitude 4 5 m 5 5 in the mediterranean region the database represents an extension to smaller magnitudes of the harvard global cmt catalog based on analysis of seismograms recorded at regional distance and modeling of intermediate period surface waves the catalog includes about 600 events 200 of which in the italian region this study extends the catalog back in time for the italian region as long as made possible by available digital data i e since 1977 with the same analysis and inversion method used for current seismicity as a result we present here 65 new moment tensors for years between 1977 and 1997 these solutions represent 45 of the total number of events analyzed the existing seismograms being often too scarce to allow a stable solution the new dataset includes events in many seismic zones where moderate seismicity had previously been scarcely documented e g the po plain the central to southern apennines and the adriatic sea the complete dataset including previously determined rcmts and cmts represents the seismic deformation in the italian area during the last 25 years

architectural styles and sedimentology of the fluvial lower beaufort group karoo basin south africa abstract the permo triassic beaufort group comprises in excess of 3000 m of sandstone and mudstone rich fluvial deposits that vary both laterally and vertically in abundance architecture and clustering styles the lower 1370 m has been studied in detail detailed stratigraphic logging and photographic interpretation have been carried out on river cliffs and hillside sections and sedimentary structures have been mapped by close inspection of clean outcrops seven fluvial architectural styles have been identified encompassing sand body and sand body cluster scales 1 flat topped sheets dominated by lateral accretion 2 concave up topped sheets dominated by lateral accretion 3 heterolithic ribbons dominated by lateral accretion 4 flat topped ribbons with attached splays dominated by downstream accretion 5 unconfined moderately amalgamated concave up topped complexes 6 unconfined strongly amalgamated sheet complexes and 7 valley confined strongly amalgamated ribbon complexes the internal architecture of each indicates mixed lateral and downstream accretion modes on several scales with local variability lateral accretion deposits differ from typically published facies models in that trough cross bedding is rare possibly the result of an inability to generate dunes due to the dominant very fine sandstone grain size the observed architecture and sedimentary structures are the product of 1 a semiarid climate producing fluvial and debris flows and cementation of sediment packages at the surface which exerts a strong control on the magnitude of channel scour the nature of channel fill and compaction history 2 local variability in subsidence rate causing variation in the vertical spacing of channel belts channel slope and plan form and variation in preservation of topographically higher features e g levees 3 relative position in a fluvial megafan influencing suspended load to bedload partitioning from proximal to distal locations and formation of channel belt complexes and 4 relative sea level changes causing incised valley formation and fill only in the most distal parts of the system

upper regime parallel lamination as the result of turbulent sediment transport and low amplitude bed forms a series of laboratory experiments has been carried out in which parallel laminated deposits were produced from an upper regime plane bed the laminae had thicknesses of a few mm and could be traced continuously over distances up to the length and width of the depositional area 0 3 m by 1 5m fluctuations in bed elevation were measured both during deposition and at equilibrium much of the bed fluctuation occurs at time scales that are too long to be due directly to turbulence as most theories for lamina formation would require we suggest instead that extremely low amplitude bed forms are present even on apparently flat beds and that the migration of these bed forms produces laterally continuous lamination all the lamination produced in the laboratory experiments was normally graded using high speed photography it was observed that the normal grading results from rapid deposition of a layer of loosely packed coarse sand several grain diameters thick followed by the slow sieving out of a well packed surface layer of finer sand the initial deposition is the result of small scale turbulent fluctuations in boundary shear stress the sieving out that follows results in a smooth surface whose low friction coefficient temporarily inhibits further deposition we term this process glazing the alignment of small scale turbulent scour and fill structures along the paths traced by migrating bedform troughs produces laterally continuous parallel lamination

sedimentology and alluvial architecture of the bajo barreal formation upper cretaceous in the golfo san jorge basin outcrop analogues of the richest oil bearing fluvial succession in argentina abstract this study addresses the sedimentology architecture and dimensions of fluvial deposits in the bajo barreal formation upper cretaceous in the codo del senguerr anticline golfo san jorge basin argentina the stratigraphic framework of the 450 650 m thick alluvial succession was carried out through description and interpretation using 18 detailed sedimentary logs along a 4 5 km wide exposure where 314 fluvial channels were analysed the bajo barreal formation is a high accommodation fluvial succession dominated by fine grained floodplain deposits with isolated to vertically stacked sheet like low sinuosity or braided fluvial channels of limited lateral mobility clustered in several coeval channel belts in which fluvial channels were relocated by avulsion the lower member consists of reworked ash fall materials preserved in floodplain areas 78 floodplain sandstones 4 and fluvial channels 18 the mean thickness of sandbodies is 2 96 m n 118 and mean true width is 112 m mean w t 43 with thicker and wider sandbodies in upper levels of the member the upper member consists of grey siltstones and mudstones preserved in extensive lowland areas 78 and fluvial channels 19 with scarce preservation of sandstones in the proximal floodplain 3 fluvial channels are narrow low sinuosity sheets with comparable thickness mean 3 21 m n 196 but greater width than those of the lower member mean width 147 m mean w t 50 paleoflow data from 298 fluvial sandbodies indicates a paleoflow direction toward the se az 112 rivers flowed parallel to inherited early cretaceous normal faults and are oriented to high angle 70 to the current axis of the codo del senguerr anticline suggesting that the uplift of the anticline occurred after the deposition of the formation the variation in geometry of fluvial channels in both members of the bajo barreal formation could help in planning and developing primary and or enhanced oil recovery projects in nearby oilfields and provide data necessary for modelling the subsurface connectivity of hydrocarbon reservoirs

sea level change and vertical land movements since the last two millennia along the coasts of southwestern turkey and israel abstract this paper provides new relative sea level data inferred from coastal archaeological sites located along the turkish coasts of the gulf of fethye 8 sites and israel between akziv and caesarea 5 sites the structures selected are those that for effective functioning can be accurately related to sea level at the time of their construction thus their positions with respect to present sea level provide a measure of the relative sea level change since their time of construction useful information was obtained from the investigated sites spanning an age range of 2 3 1 6 ka bp the inferred changes in relative sea level for the two areas are distinctly different from a rise of 2 41 to 4 50 m in turkey and from 0 to 0 18 m in israel sea level change is the combination of several processes including vertical tectonics glacio hydro isostatic signals associated with the last glacial cycle and changes in ocean volume for the israel section the present elevations of the mis 5 5 tyrrhenian terraces occur at a few meters above present sea level and vertical tectonic displacements are small data from gps and tide gauge measurements also indicate that any recent vertical movements are small the mis 5 5 shorelines are absent from the investigated section of the turkish coast consistent with crustal subsidence associated with the hellenic arc the isostatic signals for the israel section of the coast are also small ranging from 0 11 mm yr to 0 14 mm yr depending on site and earth model and the observed eustatic average sea level change corrected for this contribution is a rise of 13 5 2 6 cm during the past 2 ka this is attributed to the time integrated contribution to sea level from a combination of thermal expansion and other increases in ocean volume the observed sea levels from the turkish sites in contrast indicate a much greater rise of up to 2 2 mm yr since 2 3 ka bp occurring in a wide area between knidos and kekova the isostatic signal here is also one of a rising sea level of up to 1 mm yr and site and earth model dependent and the corrected tectonic rate of land subsidence is 1 48 mm yr this is the primary cause of dramatic relative sea level rise for this part of the coast

crevasse splay processes and deposits in an ancient distributive fluvial system the lower beaufort group south africa abstract up to 12 of the mud prone ephemeral distributive fluvial system stratigraphy in the permo triassic lower beaufort group south africa comprises tabular fine grained sandstone to coarse grained siltstone bodies which are interpreted as proximal to distal crevasse splay deposits crevasse splay sandstones predominantly exhibit ripple to climbing ripple cross lamination with some structureless and planar laminated beds a hierarchical architectural scheme is adopted in which 1 m thick crevasse splay elements extend for tens to several hundreds of meters laterally and stack with other splay elements to form crevasse splay sets up to 4 m thick and several kilometers in width and length paleosols and nodular horizons developed during periods or in areas of reduced overbank flooding are used to subdivide the stratigraphy separating crevasse splay sets deposits from crevasse splays differ from frontal splays as their proximal deposits are much thinner and narrower with paleocurrents oblique to the main paleochannel in order for crevasse splay sets to develop the parent channel belt and the location where crevasse splays form must stay relatively fixed during a period of multiple flood events beaufort group splays have similar geometries to those of contemporary perennial rivers but exhibit more lateral variability in facies which is interpreted to be the result of more extreme fluctuations in discharge regime sharp based crevasse splay packages are associated with channel avulsion but most are characterized by a gradual coarsening upward interpreted to represent progradation the dominance of progradational splays beneath channel belt deposits may be more characteristic of progradational stratigraphy in a distributive fluvial system rather than dominated by avulsion processes in a trunk river system this stratigraphic motif may therefore be an additional criterion for recognition of distributive fluvial systems in the ancient record

fault activity and marine terracing in the capo vaticano area southern calabria during the middle late quaternary abstract the capo vaticano peninsula is a structural high bordered by several normal fault segments mainly striking ne sw and wnw ese and belonging to the so called siculo calabrian rift zone both the two fault systems extend in the tyrrhenian offshore and show recent activity in the capo vaticano peninsula six orders of marine terraces with their preserved paleoshorelines and a top surface have been recognised they form a continuous set of morphological elements ascribed to the last seven principal high stands of the eustatic curve occurred from 330 to 60 kyr on the basis of new chronological data available in the recent literature the morphotectonic analysis of the paleoshorelines allowed recognition of a deformation pattern characterised by a northeastward tilting of the area and to quantify the uplift rates moreover vertical slip rates ranging between 0 25 and 2 5 mm yr have been calculated for a wnw ese trending fault segment the coccorino fault in this structural framework the late quaternary uplift of the capo vaticano peninsula can be related to the activity of both the ne sw and wnw ese striking normal fault systems added to the regional component of uplift the recent activity of these structures is also suggested by the 1905 seismic event that occurred offshore of the capo vaticano peninsula

criteria for differentiating microbial caddisfly bioherms from those of marine polychaetes in a lacustrine setting paleocene second member funing formation subei basin east china abstract paleogene carbonate successions from lacustrine basins across east china yield microbial bioherms containing abundant agglutinated fossil tubes historically these have been interpreted as the dwellings of polychaetes introduced by marine incursions this is problematic because these tubes are associated with abundant non marine fauna and algae diverse and exceptionally well preserved fossil tubes from carbonate microbial bioherms were studied in outcrops and drill cores of the second member of the paleocene funing formation subei basin east china detailed macro meso and micro structural investigations of these tube dominated bioherms reveal that the putative marine polychaete tubes better fit the morphologies and construction styles of lacustrine caddisfly insecta trichoptera larval cases eliminating the need for a marine influence on this lacustrine setting individual caddisfly cases are commonly 10 25 mm in length and 1 2 5 mm in diameter and form slightly curved tapered tubes or coiled spirals twelve tubular case construction styles were further identified based on caddisfly case wall structures and dominant grain types caddisfly cases are commonly single walled with rarer nested instar cases comprising double or triple walls of different sizes most cases are fully agglutinated with neatly arranged similarly sized and closely connected particles of clastic grains carbonate particles plant fragments and phosphatic fish bones sparsely agglutinated cases are also present but much rarer and conform to the silk larval cases of caddisflies the caddisfly cases appear as gregarious aggregations within carbonate microbial bioherms the microbial caddisfly bioherms in this study are commonly developed on carbonate hardground or mudstone within the wave washed high energy shallow lacustrine littoral zone and can be traced along the western paleolake margin of the jinhu depression of the subei basin for up to 60 km the bioherms are composed of repeated microbial caddisfly couplets made up of randomly arranged and similarly sized caddisfly cases encrusted by domed planar columnar or cauliflower like microbial layers cyclic microbial caddisfly couplets fit well with caddisfly biology but are not known to occur with marine polychaetes this is the first report of microbial caddisfly bioherms in cenozoic strata of china and is the oldest cenozoic record of caddisflies in china

new insights on the subsidence of lipari island aeolian islands southern italy from the submerged roman age pier at marina lunga abstract lipari island belongs to the aeolian archipelago located in the southern tyrrhenian sea italy which is one of the most active volcanic areas of the mediterranean basin although this region has been settled since prehistory only during roman times were coastal installations built in these islands in this study we present and discuss data on the relative sea level change estimated from a submerged pier of roman age dated 2100 100 bp this structure about 140 60 m is located along the coast of marina lunga corresponding to the present location of the main harbor of lipari island this pier which was accidentally discovered in 2008 during preliminary excavations for the construction of a new pier is a valuable indicator of relative sea level changes and vertical land movements its top surface is presently located at 9 1 0 05 m while the foundations at the outer end of the pier are at 11 6 0 05 m above a shoreline placed at 13 0 0 05 m we studied this site through direct archaeological investigations and ultra high resolution multibeam bathymetry the current submergence of this pier can be explained by the cumulative effect of the relative sea level changes caused by the regional glacio hydro isostatic signal active since the end of the last glacial maximum and the local volcano tectonic land subsidence from our investigations a relative sea level change at 12 3 0 7 m with a subsidence rate at 5 79 0 01 mm y 1 and an average value of volcano tectonic contribution at 5 17 0 01 m y 1 for the last 2100 100 years bp is estimated from comparison against the latest predicted sea level model for the southern tyrrhenian sea these rates of relative sea level change led to the disuse of the harbor after around the fourth century ad in agreement with archaeological interpretations our results provide new insights on the recent evolution of this active volcanic area

sea level in roman time in the central mediterranean and implications for recent change instrumental records indicate that ocean volumes during the 20th century have increased so as to raise eustatic sea level by f1 2 mm year and the few available records suggest that this is higher than for the previous century geological data indicate that ocean volumes have increased since the main phase of deglaciation about 7000 years ago but whether this continued into the recent past remains unclear yet this is important for establishing whether the recent rise is associated with global warming or is part of a longer duration non anthropogenic signal here we present results for sea level change in the central mediterranean basin for the roman period using new archaeological evidence these data provide a precise measure of local sea level of 1 35f0 07 m at 2000 years ago part of this change is the result of ongoing glacio hydro isostatic adjustment of the crust subsequent to the last deglaciation when corrected for this using geologically constrained model predictions the change in eustatic sea level since the roman period is 0 13f0 09 m a comparison with tide gauge records from nearby locations and with geologically constrained model predictions of the glacio isostatic contributions establishes that the onset of modern sea level rise occurred in recent time at f100f53 years before present d 2004 elsevier b v all rights reserved

a systematic framework for formulating convex failure envelopes in multiple loading dimensions the failure envelope approach is widely used to assess the ultimate capacity of shallow foundations for combined loading and to develop foundation macro element models failure envelopes are typic

origins of massive type sandstones in braided river systems abstract this study details largely ignored massive type predominantly structureless sandstones preserved within braided fluvial successions of carboniferous to triassic age architectural element analysis reveals that these sediments were deposited within sand dominated perennial systems of low braiding index cross stratified braid bar deposits are interbedded with and laterally equivalent to geometrically distinct largely structureless massive type sandbodies identified as two separate architectural elements channel like smc and sheet like sms sub divisions within these broad categories define six geometric units which are texturally distinct from each other and from the structured sediments of the same lithological unit since massive type sandstone elements have many features in common with the deposits of highly concentrated laminar sediment water flows they are interpreted in terms of similar depositional processes smc elements form elongate channel like features which trend both at high angles to and parallel with the palaeoflow of host fluvial channels the lower bounding surfaces of smc elements may be either erosive or non erosive and describe symmetrical cross sections with margins dipping 250 m parallel and transverse to the fluvial palaeoflow direction established from cross stratified sandstones of adjacent architectural elements the basal surface of sms elements may either be undulose where the sandbodies are termed smsu or erosional where they are termed smse internally smsu elements preserve parallel laminae marginal to basal scours diffuse sweeping laminae isolated cross sets and water escape structures the smsu sediments are compositionally identical to the structured sandstones with which they are associated and are interpreted as the result of deposition from highly concentrated stream flows developed through flooding and entrainment of sandy floodplain material along the basal surface of smse elements scours in excess of 4 5 m are preserved which are elongate both parallel and oblique to fluvial flow these are commonly lined with a mudclast breccia and or massive sandstone with crude laminae developed parallel with the margin in the upper portion of smse elements diffuse dune structures and sweeping laminae are preserved smse units are texturally and compositionally immature with respect to the cross stratified sandstones with which they are associated thus they are believed to be of first cycle origin and are interpreted as the deposits of highly concentrated flows possibly generated by glacial outburst floods or jokulhaups

anatomy and dimensions of fluvial crevasse splay deposits examples from the cretaceous castlegate sandstone and neslen formation utah u s a abstract crevasse splay deposits form a volumetrically significant component of many fluvial overbank successions up to 90 in some successions yet the relationships between the morphological form of accumulated splay bodies and their internal facies composition remains poorly documented from ancient successions this work quantifies lithofacies distributions and dimensions of exhumed crevasse splay architectural elements in the campanian castlegate sandstone and neslen formation mesaverde group utah usa to develop a depositional model fluvial crevasse splay bodies thin from 2 1 m average to 0 8 m average and fine from a coarsest recorded grain size of lower fine sand to fine silt away from major trunk channel bodies internally the preserved deposits of splays comprise laterally and vertically variable sandstone and siltstone facies associations proximal parts are dominated by sharp and erosional based sandstone prone units which may be structureless or may comprise primary current lineation on beds and erosional gutter casts medial parts comprise sets of climbing ripple strata and small scale deformed beds distal parts comprise sets of lower stage plane beds and complex styles of lateral grading into fine grained floodbasin siltstones and coals lithofacies arrangements are used to establish the following i recognition criteria for crevasse splay elements ii criteria for the differentiation between distal parts of crevasse splay bodies and floodplain fines and iii empirical relationships with which to establish the extent ca 500 m long by 1000 m wide and overall semi elliptical planform shape of crevasse splay bodies these relationships have been established by high resolution stratigraphic correlation and palaeocurrent analysis to identify outcrop orientation with respect to splay orientation this permits lateral changes in crevasse splay facies architecture to be resolved facies models describing the sedimentology and architecture of crevasse splay deposits preserved in floodplain successions serve as tools for determining both distance from and direction to major trunk channel sandbodies

the holocene sea level story since 7500 bp lessons from the eastern mediterranean the black and the azov seas abstract this paper addresses the obvious controversy between the so far published sea level curves of the black sea and the mediterranean it starts with a discussion of the methods of reconstructing sea level curves the evaluation of sea level indicators and the application of the radiocarbon dating method at least since 7500 bp when the black sea and the mediterranean were connected both water bodies must have reacted synchronously on glacio eustatic changes it is documented that none of the mediterranean sea level curves shows the major wiggles postulated for the black sea which are supposed to reflect trans and regression cycles the very shallow bathymetric condition of the azov sea and the northern black sea should have led to considerable and traceable shoreline displacements there is neither archaeological nor historical evidence of mid and late holocene regressions of several meters the tectonic setting of the black and azov seas implicates that the tectonic signal often overrides the eustatic one therefore only local sea level curves can be established in this paper based on vibracores a locally valid sea level curve for the taman peninsula is demonstrated layers of paralic peat were used as sea level indicators and for 14 c dating the shape of this curve follows the one known from the mediterranean this study also revealed that the present peninsula of taman evolved out of a former archipelago

sea level change during the holocene in sardinia and in the northeastern adriatic central mediterranean sea from archaeological and geomorphological data abstract we provide new data on relative sea level change from the late holocene for two locations in the central mediterranean sardinia and ne adriatico they are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea level elevation twelve submerged archaeological sites were studied six aged between 2 5 and 1 6 ka bp located along the sardinia coast and a further six dated 2 0 ka bp located along the ne adriatic coast italy slovenia and croatia for sardinia we also use beach rock and core data that can be related to holocene sea level the elevations of selected significant archaeological markers were measured with respect to the present sea level applying corrections for tide and atmospheric pressure values at the time of surveys the interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea these data are compared with predictions derived from a new glacio hydro isostatic model associated with the last glacial cycle sardinia is tectonically relatively stable and we use the sea level data from this island to calibrate our models for eustatic and glacio hydro isostatic change the results are consistent with those from another tectonically stable site the versilia plain of italy the northeast adriatic italy slovenia and croatia is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions this indicates that the adriatic coast from the gulf of trieste to the southern end of istria has tectonically subsided by 1 5 m since roman times

evidence of active subsidence at basiluzzo island aeolian islands southern italy inferred from a roman age wharf abstract the aeolian arc southern tyrrhenian sea italy is one of the most active volcanic areas of the mediterranean basin affected by volcanic hydrothermal and seismic activity ancient populations settled this region since historical times building coastal installations which currently are valuable archaeological indicators of relative sea level changes and vertical land movements in this study we show and discuss data on the relative sea level change estimated from a submerged wharf of roman age dated between 50 b c and 50 a d located at basiluzzo island this structure has been studied through marine surveys and archaeological interpretations and is presently located at a corrected depth of 4 10 0 2 m we explain this submergence by a cumulative effect of the relative sea level change caused by the regional glacio hydro isostatic signal active since the end of the last glacial maximum and the local volcano tectonic land subsidence finally a total subsidence rate of 2 05 0 1 mm yr 1 with a volcano tectonic contribution of 1 43 0 1 mm yr 1 for the last 2 ka bp is inferred from the comparison against the latest predicted sea level curve for the southern tyrrhenian sea suggesting new evaluations of the volcano tectonic hazard for this area of the aeolian islands

occurence of the trace fossil beaconites antarcticus in the lower carboniferous fluviatile rocks of county mayo ireland abstract large straight curved or sinuous endichnial burrows with a meniscus pattern of infilling are described from lower carboniferous red beds of county mayo ireland the burrows have been identified as beaconites antarcticus the burrows show a strong facies association being concentrated in the upper parts of sandstones deposited during floods in shallow possibly ephemeral stream channels they appear to be absent from the overlying non red fluvial sandstones which show evidence for deeper more sinuous and more permanent channels it is suggested that burrowing was related to varying moisture content of the sediment the burrows were probably formed by locomotory back packing of arthropods or vertebrates but the precise nature of the producer remains unknown

flaser and wavy bedding in ephemeral streams a modern and an ancient example abstract flaser and wavy bedding are sedimentary structures characterized by alternating rippled sand and mud layers these structures often are considered to form mostly in tidally influenced environments published examples from fluvial environments are rare flaser and wavy bedding were found in two ephemeral stream deposits the jurassic kayenta formation and the modern wash in seven mile canyon both located in southeastern utah usa these examples demonstrate that flaser bedding can form and be preserved in ephemeral streams

invertebrate trace fossils in semi arid to arid braided ephemeral river deposits of the mississippian middle member of the mauch chunk formation eastern pennsylvania usa abstract the rapid diversification of terrestrial ecosystems was initiated in the silurian and subsequently continued through the mississippian detailed collecting of the middle member of the mississippian mauch chunk formation in eastern pennsylvania has yielded a number of important vertebrate and invertebrate trace fossils indicating the presence of a significant terrestrial biotic diversity during the early carboniferous this report illustrates the diverse invertebrate trace fossil assemblage associated with the ephemeral river systems of the mauch chunk the mauch chunk invertebrate ichnoassemblage consists of backfilled burrows of deposit feeders both meniscate taenidium and non meniscate planolites that typically cross cut bedding arthropod trackways diplichnites diplopodichnus stiaria kouphichnium and stialla striated trails cruziana and resting traces rusophycus and surface or shallow subsurface grazing trails or burrows gordia tetrapod footprints mostly made by temnospondyl amphibians are also part of this ichnoassemblage the mauch chunk invertebrate ichnoassemblage corresponds well to the scoyenia ichnofacies in consisting of simple burrows trackways striate and bilobate trails and pits and simple meniscate burrows typically trace fossils of the scoyenia ichnofacies indicate opportunistic behaviors in subaerial environments that are temporarily or periodically inundated indeed the palaeoenvironmental setting of these traces is a semi arid to possibly arid braided ephemeral river system with extensive overbank deposits the invertebrate traces were developed both as infaunal burrows in the tops and within channel sandstones and as surface and grazing traces on in channel mudstone draped bedforms and in proximal overbank deposits the in channel mudstone draped bedforms display both vertebrate and invertebrate trace fossils the mauch chunk invertebrate ichnofossil assemblage resembles other devonian through triassic ichnoassemblages from ephemeral fluvial red beds confirming that the terrestrial invertebrate fauna had already fully colonized fluvial environments by mississippian time furthermore the development of the scoyenia ichnoguild in the mauch chunk formation in the form of abundant traces of deposit feeders of a shallow to intermediate depth infauna esp taenidium is unusually early when compared to the previously known palaeozoic record

paleosol and ichnofossil evidence for significant neotropical habitat variation during the late middle miocene serravallian we use paleopedology and ichnology to elucidate the habitat of the late middle miocene fossil site of quebrada honda southern bolivia the paleosols represent three pedotypes type 1 and type 2 paleosols are interpreted as inceptisols eutrudepts and entisols udifluvents respectively which formed on proximal and distal floodplains in a seasonal sub humid to humid wooded grassland like vegetative community type 3 paleosols are interpreted as inceptisols calciustepts that formed in more densely vegetated wooded grassland like vegetative communities on distal floodplains in a strongly seasonal sub humid to semi arid environment the ichnofossil assemblage of quebrada honda includes celliforma coprinisphaera taenidium fictovichnus planolites skolithos katarrhedrites and root traces and represents heterogeneous communities dominated by soil arthropods and plants the physical and geochemical properties of the paleosols including low maturity poor development of horizons and the overall moderate estimates of mean annual precipitation indicate changes in soil moisture due to seasonal precipitation and flooding and low but varying degrees of temporal stability the diverse ichnofossil assemblage of quebrada honda reflects environments with greater primary productivity and temporal stability than those of nearby cerdas bolivia which are several million years older quebrada honda s inferred paleoenvironments differ markedly from those of la venta colombia indicating that dissimilar habitats may partly or principally account for the vastly different faunas of these two well sampled and contemporaneous fossil localities

amphibian burrows and ephemeral ponds of the lower permian speiser shale kansas evidence for seasonality in the midcontinent abstract burrows attributed to the lysorophid brachydectes elongatus occur within a green mudstone lens in the lower permian wolfcampian speiser shale council grove group of eastern kansas the burrow bearing unit consists of a 100 m long lens of massive calcareous silty mudstone with a maximum thickness of 35 cm the lens also contains the fossils of fish amphibians reptiles charophytes stomachara and ostracodes carbonita the mudstone lens pinches out laterally into red pedogenically modified mudstone the burrows occur in three layers at the top of each layer is a subaerial exposure surface indicated by rhizoliths mudcracks and coarse grained lags the mudstone lens is interpreted as the deposit of a shallow ephemeral pond the burrows occur in three vertically and temporally separated clusters with concentrations up to 20 m2 the burrows show two types of architecture type i burrows are elongate elliptical tubes 4 32 cm long and 2 7 cm in width type ii burrows are short elliptical tubes 1 5 3 5 cm in length and 2 5 5 cm in width the burrow fill consists of a mudstone capped by sandy siltstone each burrow layer contains a varying number of articulated and disarticulated lysorophid skeletons within the burrows and surrounding matrix while similar to permian lungfish burrows the architecture and surficial morphology of the lysorophid burrows permits their distinction even in the absence of body fossils the occurrence of burrow layers capped by subaerial exposure surfaces and separated by layers of non burrowed massive mudstone indicates that burrowing occurred in response to episodic perhaps seasonal droughts on the permian coastal plain the lysorophid burrowing behavior is analogous to that of the extant amphibians amphiuma sp and siren intermedia which inhabit rivers and ponds in the southeastern usa

trace fossil analysis of lacustrine facies and basins abstract two ichnofacies are typical of lacustrine depositional systems the scoyenia ichnofacies characterizes transitional terrestrial nonmarine aquatic substrates periodically inundated or desiccated and therefore is commonly present in lake margin facies the mermia ichnofacies is associated with well oxygenated permanent subaqueous fine grained substrates of hydrologically open perennial lakes bathymetric zonations within the mermia ichnofacies are complicated by the wide variability of lacustrine systems detected proximal distal trends are useful within particular lake basins but commonly difficult to extrapolate to other lakes other potential ichnofacies include the typically marine skolithos ichnofacies for high energy zones of lakes and substrate controlled still unnamed ichnofacies associated to lake margin deposits trace fossils are useful for sedimentologic analysis of event beds lacustrine turbidites are characterized by low diversity suites reflecting colonization by opportunistic organisms after the turbidite event underflow current beds record animal activity contemporaneous with nearly continuous sedimentation ichnologic studies may also help to distinguish between marine and lacustrine turbidites deep marine turbidites host the nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea deep lacustrine environments contain the mermia ichnofacies which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems the lower diversity of lacustrine ichnofaunas in comparison with deep sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of lacustrine facies paleozoic lacustrine ichnofaunas are typically dominated by surface trails with little associated bioturbation during the mesozoic bioturbation depth was higher in lake margin facies than in fully lacustrine deposits while significant degrees of bioturbation were attained in lake margin facies during the triassic major biogenic disruption of primary bedding in subaqueous lacustrine deposits did not occur until the cretaceous

deformation of the 125 ka marine terrace in italy tectonic implications in peninsular italy marine terraces and shorelines created during oxygenisotope substage 5e known historically as the tyrrhenian highstand provide a reliable and homogeneous datum of vertical motions during the past 125 000 years published accounts of 121 locations on the tyrrhenian inner edge were reinterpreted and used to calculate both local and regional uplift rates the data show arching of southern italy between the tyrrhenian and the adriatic coasts and of the calabrian arc between the sangineto and the longi taormina tectonic lineaments at rates of up to 1 2 mm yr for the past 125 ka they also suggest that the present configuration of the southern apennines is the product of post early pleistocene regional uplift superimposed on tortonian to early pleistocene thrusting uplift patterns are characterised by different wavelength in different geodynamic settings suggesting a close link with the depth of the causative tectonic sources

an ichnofossil assemblage from the lower carboniferous snowy plains formation mansfield basin australia abstract continental strata of the home station sandstone member of the snowy plains formation of the mansfield group avon supergroup mansfield basin in victoria australia contains diverse and abundant trace fossils including domichnia fodinichnia pascichnia and repichnia the ichna are found in numerous beds in an approximately 28 m thick unit referred to as fish hill within the 250 to 500 m thick home station sandstone member the beds consist of alternating laminated mudstone and siltstone thick bedded ripple laminated sandstone and thick bedded massive sandstone with occasional discontinuous wavy lamination trough cross bedding and small scale planar cross bedding interpreted as meandering river deposits the trace fossil assemblage includes rusophycus cruziana palaeophycus and sagittichnus a new ichnospecies of fuersichnus and of margaritichnus and a new ichnotaxon platicytes lioparadus the geological and geographical distributions of many of these ichnotaxa are extended excellent examples of the compound nature of cruziana and rusophycus are illustrated ichnotaxa are herein grouped into a rusophycus margaritichnus and cruziana ichnocoenoses each identified according to their paleoenvironmental occurrence this is the first detailed description on ichnofossils reported from fish hill adding important palaeoenvironmental and palaeoecological information to what is previously known from these rocks based on vertebrate fossils

fossilized worm burrows influence the resource quality of porous media burrow associated selective dolomitization in the yeoman formation limestone ordovician williston basin is characterized by distinct textural heterogeneity physical parameters such as permeability porosity tortuosity and dispersivity are therefore difficult to assess this study compares the relative dispersivities of three geologic media homogeneous sandstone fractured limestone and burrowed dolomitic limestone results show that the flow paths present in burrow associated dolomite are tortuous and that the interaction between the flow paths and the matrix is extensive such rocks act as dual permeability systems in the subsurface hydrocarbon production from such deposits will be strongly influenced by burrow related heterogeneity and its influence should be carefully considered before secondary recovery schemes are implemented

facies model for fluvial systems in the seasonal tropics and subtropics facies models that summarize the deposits of fluvial systems are well established for humid climate settings and for desert environments but the deposits of rivers in the sub humid and semiarid seasonal tropics have been largely ignored our observations and data from modern streams and recent deposits in northeastern australia show how such rivers with extremely variable discharge have distinctive deposit characteristics that are substantially different from conventional fluvial facies models these properties include 1 erosionally based channel fill lithosomes that exhibit complex lateral facies changes with 2 abundant pedogenically modified mud partings 3 complex internal architecture that may lack the macroform elements typical of other fluvial sediment bodies 4 an abundance of sedimentary structures formed under high flow stage and 5 an abundance of in situ trees that colonize channel floors and are adapted to inundation by fast flowing water we illustrate examples of this fluvial style from the rock record and set out a new facies model the recognition of such a distinctive fluvial character and of changes in character through vertical successions will aid paleoclimate and reservoir analysis

archaeological and geomorphological indicators of the historical sea level changes and the related palaeogeographical reconstruction of the ancient foreharbour of lechaion east corinth gulf greece abstract study of the architectural morphological and constructional features of the coastal harbour installations of the ancient foreharbour of lechaion indicates that they were built or rebuilt during the period of the roman domination of corinth and has facilitated the reconstruction of the vertical movements and the palaeogeography of the coast on the basis of the current position of the sea level indicators including beachrocks fossilized uplifted and submerged marine notches and ancient coastal harbour installations and the relationship between them the sea level during the roman operation of the harbour was determined to be 0 90 m lower than at present furthermore the subsequent abandonment of the harbour and the siltation of its constructions were determined during two successive tectonic subsidence co seismic events the sea level rose by 2 0 m in total 1 60 m during the first event and 0 40 m during the second one a strong uplift tectonic event followed and the sea level dropped by 1 10 m this regression of the sea was responsible for the present shoreline morphology determination of the sea level fluctuation at the shore of the ancient harbour of lechaion allowed the palaeogeographical reconstruction of the coast in different stages related to these changes

impact of marine incursions on lacustrine source rocks organic matter quantity quality and kinetics in the paleocene south yellow sea basin offshore eastern china abstract the impact of marine incursions during transgression on the quantity and quality of organic matter in lacustrine source rocks is critical to understanding their source rock properties and therefore on their hydrocarbon generation potential but is also challenging and controversial here we examine this issue based on a case study in the south yellow sea basin sysb offshore eastern china addressing organic matter om quantity quality and petroleum generation kinetics a total of 139 lacustrine source rock samples was collected from the fourth member of the paleocene funing formation e1f4 in the sysb and investigated for organic petrographic and geochemical characteristics the samples are immature to early oil window mature and the om in all samples is dominated by terrigenous material as shown by the organic petrography relatively low hydrogen indices and biomarker distributions the sediments are classified as inert to gas prone however the presence of marine fossils red and brown algae coccolithophores and probably neomonoceratinabullata and the biomarker results suggest that marine incursions occurred during the deposition of the lower unit of the e1f4 e1f4l the samples from this unit display higher hi values and more depleted 13corg ratios but lower toc and s1 s2 contents than the upper unit of the e1f4 e1f4u source rocks without marine influence this suggests that marine incursions primarily improved the quality rather than quantity of organic matter bulk kinetics indicated that marine incursions also led to a more homogenous om and compositional kinetics and phase properties suggest that black oil is generated throughout the process of kerogen conversion thus our data suggest that marine incursions had a positive effect on the om quality and oil generation potential of these lacustrine source rocks therefore the impact of marine incursions should be fully considered during source rock evaluation of coastal lacustrine basins especially during high sea level stages in addition the greatest hydrocarbon exploration potential is observed in the south 4th sag of the southern depression and thus this study provides valuable data for shaping regional exploration strategy in the sysb

the sediment stratigraphy of a flood event an example from the sabie river south africa abstract the geomorphic effects of river floods in various climatic settings worldwide have been extensively described but there is little information on sedimentary processes during and immediately following flood peaks here we reconstruct sedimentary processes and patterns of the 2012 flood on the sabie river in kruger national park south africa from the preserved geomorphic and sedimentary signature of this event based on a combination of geomorphic and sedimentary evidence the maximal and waning flow stages of the flood event are identified shown by cut and fill and fining up sequences within aggradational bars and organic horizons which may be buried that correspond to the period of flood peak recession the presence of organic horizons suggests a strongly seasonal flow regime typical of semi arid south african rivers it also provides an exemplar of a flood event stratigraphy that is usually poorly preserved in the geologic record

evidence of vertical tectonic uplift at briatico calabria italy inferred from roman age maritime archaeological indicators abstract calabria is one of the most complex geological regions of the mediterranean basin which experienced large earthquakes and uplift and is still undergoing active tectonics along its coasts are located archaeological sites that can be used as powerful indicators of the relative vertical movements between land and sea since their construction this paper presents and discusses data on the relative sea level change as estimated from maritime archaeological indicators of the last 2 0 ka bp existing along the tyrrhenian coast of briatico these sites still show the remnants of a roman age fish tank and a submerged breakwater about 320 m long the palaeo sea level has been obtained measuring the functional elevation of the significant archaeological markers their elevation was compared against the latest predicted sea level curve for the holocene along the tyrrhenian coast of calabria as this coastal area is affected by significant and continuous vertical tectonic uplift during pleistocene the data show the counterbalance between coastal uplift and relative sea level change caused by the glacio hydro isostasy acting since the construction of these archaeological sites the sum of these movements determined an about null relative sea level change for this location these data are in contrast with other part of the tectonically stable areas of the mediterranean and provide evidence that crustal uplift continued in the last 1806 50 y at a rate of 0 65 mm y

trace fossils in fluvial deposits of the duchesne river formation eocene uinta basin utah abstract a diverse suite of nonmarine trace fossils is present in a late eocene sandstone siltstone mustone sequence in the duchesne river formation of northeastern utah on the basis of primary sedimentary structures and stratification sequences the beds are interpreted as deposits in meandering and braided stream environments the trace fossils include ancorichnus muensteria m palaeophycus scoyenia skolithos two unidentified ichnotaxa and rhizoliths insects and oligochaetes apparently made most of the animal traces in moistor wet cohesive stream sediment during subaerial exposure or under thin water cover

ichnology and sedimentology of the trace fossil bearing fluvial red beds from the lowermost member of the paleocene funing formation in the jinhu depression subei basin east china abstract the lowermost member of the paleocene funing formation which is composed of bioturbated fluvial red beds is extensively distributed throughout the jinhu depression subei basin east china despite its economic value as one of the most important oil bearing reservoirs in the subei basin the sedimentology ichnology and paleoenvironment of this formation in the jinhu depression remain poorly understood in this work we investigated the ichnofossils and sedimentary facies analyzed the ichnofacies and potential tracemakers and reconstructed the paleoenvironment of the jinhu depression based on cores from the lowermost member of the paleocene funing formation this formation contains a moderately diverse ichnofauna 9 ichnotaxa of the scoyenia ichnofacies that includes meniscate burrows taenidium barretti taenidium satanassi and beaconites coronus simple horizontal cylindrical burrows palaeophycus tubularis palaeophycus heberti and planolites isp simple vertical or subvertical burrows skolithos linearis and skolithos isp and plant root traces the other complex branched and chambered burrows are left in open nomenclature these ichnofossils are widespread throughout the three facies associations identified in this study 1 ephemeral fluvial channel 2 crevasse splay and 3 distal floodplain facies associations multiple lines of sedimentological and ichnological evidence namely the predominance of massive and upper flow regime structures the occurrence of invertebrate burrows e g skolithos and taenidium in the lower and middle parts of the channel deposits and the dramatic changes in the color and mottling in channel and overbank sediments indicate that the river discharge was short lived and that the water table was highly variable the variations in the discharge and water level are attributed to the influence of seasonal rainfall the cyclic nature of intense rainfall events and dry periods suggests that the subei basin was likely located in a semiarid region with a seasonal rainfall pattern during the early paleocene this study also reveals that the ephemeral fluvial channel is the facies association with the highest potential to yield oil bearing reservoirs in the paleocene red beds of the jinhu depression additionally the influence of bioturbation on the reservoir quality in this region should be considered in future research

influence of normal fault growth and linkage on the evolution of a rift basin a case from the gaoyou depression of the subei basin eastern china abstract it is widely acknowledged that the growth and linkage of a boundary fault affects the evolution of the accompanying sedimentary basin and exerts a strong influence on its sedimentary characteristics in this study we attempt to discuss the evolution of a boundary fault and rift basin by using seismic interpretation incremental fault throw and growth rate distance g d profile which are more suitable parameters than the expansion index in rift basins where footwall strata are missing because of erosion or a depositional hiatus therefore the gaoyou depression is taken as an example the gaoyou depression is the largest hydrocarbon bearing depression in the subei basin which is a representative rift basin in eastern china the depression is bounded to the south by the jiangdu wubao fault zone which includes the zhen 1 wu 1 zhen 2 and wu 2 faults using high resolution three dimensional seismic data the zhen 1 wu 1 fault can be subdivided into four segments based on its g d profile the shaobo fanchuan liuwushe and liulu segments growth rates indicate that the zhen 1 wu 1 fault and the zhen 2 and wu 2 faults developed successively from the late cretaceous to the miocene during rifting of the gaoyou depression and that development of the zhen 2 and wu 2 faults was controlled by the zhen 1 wu 1 fault the four segments of the zhen 1 wu 1 fault were linked with each other by the time the zhen 2 and wu 2 faults formed in the late paleocene an evolution model of the gaoyou depression is set up in this study integrating the fault activity with previous sedimentological studies we suggest that the evolution of the gaoyou depression was controlled by the jiangdu wubao fault zone rather than by a single fault successive slip of the zhen 1 wu 1 fault and the zhen 2 and wu 2 faults caused subsidence and migration of the depocenters this study presents a case investigation of the effects of boundary faults on rift basins in eastern china

present day kinematics of the plate boundary zone between africa and europe from the azores to the aegean anticlockwise rotation of africa relative to europe around an euler pole in the eastern atlantic causes plate convergence in the central mediterranean towards n20 w at rate considered a priori to be 5 10 mm yr 1 however previous summaries of the present day deformation sense in the central mediterranean are inconsistent with observations in southern italy recent investigations of italy and adjacent parts of north africa enable local deformation sense observed to be reconciled with sense predicted from relative plate motions suggested angular velocity of the african plate relative to europe is 0 07 myr 1 around a pole near 21 n 21 w this predicts 2 6 mm yr 1 maximum extension rate towards n64 e near the azores consistent with the minimum local accretion of new oceanic crust in the past few millions of years and 4 3 mm yr 1 plate convergence towards n20 w in the central mediterranean at 13 e further east the northern margin of the african plate can be regarded as the gargano seismic zone in the central adriatic sea the northern adriatic sea is a microplate rotating anticlockwise relative to europe at 0 3 myr 1 around a pole in northwestern italy causing northeastward shortening in yugoslavia and up to 4 mm yr 1 extension in central and northern italy the african plate is deforming internally in tunisia and northern libya extending obliquely in direction e10 s at rate up to 5 5 mm yr 1 the resultant velocity relative to europe in the ionian and southern adriatic seas 5 mm yr 1 towards n50 e explains the observed relative velocity across southern italy kinematic consistency requires present day shortening rate east of calabria associated with subduction on the tyrrhenian sea benioff zone and tyrrhenian sea extension rate to be both zero or equal to within 1 mm yr 1

vertical land movements and sea level changes along the coast of crete greece since late holocene abstract geomorphological survey along the coasts of crete revealed widespread evidence of uplifted and submerged tidal notches different phases of beachrock formation and many relics of ancient coastal constructions about 1 6 ka bp when the sea level was at 1 25 0 05 m the western tectonic block of the island uplifted by 9 15 0 20 m in its westernmost extremity and by 2 00 m approximately in its eastern boundary and tilted southeastward repeated preceding episodes of subsidence submerged the western part of the island by 1 60 m in a period of 2300 years along the western coast the younger phase of the submerged beachrocks was identified and measured at nineteen locations together with the submerged tidal notches and archaeological remains land subsidence by 1 25 0 05 m subsequent to the uplift of the western part occurred after the late venetian occupation period ad 1600 coincident with the submersion of the eastern part of the island in central and eastern crete the relative sea level change evidence from tidal notches and beachrocks revealed five distinct sea level stands at 6 55 0 55 m 3 95 0 35 m 2 70 0 15 m 1 25 0 05 m and 0 55 0 05 m the lowest sea level stand can be identified with the oldest dated tidal notch of western crete between 4200 90 b p and 3930 90 b p two subsequent sea levels can be linked with the protopalatial 1900 1700 b c or 1600 b c and neopalatial period 1600 1450 b c of the minoan civilization according to submerged prehistoric morphologies and inundated minoan constructions the change of sea level from 2 70 0 15 m to 1 25 0 05 m is placed between 1450 b c and the fourth century bc the dating of 1 25 0 05 m sea level stand was based on the measurement and interpretation of ancient coastal installations built along the coast of central and eastern crete during classical hellenistic roman byzantine and venetian periods historical sources report a relative sea level rise by 0 70 m during the ad 1604 paroxysmal event over the last 400 years the relative sea level rose by 0 55 m the uplift of the coast of western crete and the submersion in its central and eastern coast indicate that during the ad 365 paroxysmal event the island was split along a tectonic boundary identified with the neotectonic graben of spili and its northern and southern prolongation

recognizing products of palaeoclimate fluctuation in the fluvial stratigraphic record an example from the pennsylvanian to lower permian of cape breton island nova scotia tectonics and climate are the major extrinsic upstream controls on both the external and internal architectures of fluvial channels while the role of tectonics has been well documented the role of climate has received less attention because both tectonics and climate can produce similar stratigraphic architectures the ability to recognize and differentiate these has major ramifications for the interpretation of fluvial stratigraphy the pennsylvanian to permian succession of the maritimes basin complex on cape breton island is ca 5 km thick and is composed of predominantly non marine strata deposited within a series of depocentres characterized by different subsidence regimes basins in the west are transtensional depocentres characterized by episodic fault movement in contrast basins in the east were formed during prolonged periods of passive thermal subsidence the stratigraphy is composed of four second order sequences a to d each 5 to 10 myr in duration these sequences are composed of amalgamated fluvial channel deposits that fine upwards into extensive mud dominated floodplain deposits with isolated fluvial channel bodies a spectrum of fluvial styles is recorded within the study area including perennial perennial intermittent and ephemeral four stratigraphic intervals e1 to e4 are recognized in which the deposits of strongly seasonal perennial intermittent fluvial deposits are predominant these intervals 2 to 6 myr in duration are correlated across the study area between basins with differing tectonic regimes and do not correlate with a particular position in second order sequences this suggests that climate exerted the dominant influence on the formation of these intervals and can be differentiated from tectonic imprints while the tectonic regime of a particular basin exerted a fundamental control on the external architecture a coherent record of climate change is recognized in the internal architecture of fluvial units this study demonstrates that tectonic and climatic controls can be recognized and differentiated in vertical successions by evaluating the changes in fluvial architecture