accelerated ice mass depletion revealed by low degree gravity field from satellite laser ranging greenland 1991 2011 1 we detect the acceleration of ice mass depletion in greenland for the period 1991 2011 from the low degree gravity field up to degree and order 4 derived from the satellite laser ranging slr data between 2003 and 2011 during the era when the grace gravity recovery and climate experiment satellite data are available our slr results of gravity changes agree well with grace showing significant negative patterns in greenland prior to that the slr linear trend maps show a near balance in greenland ice mass during 1991 2002 after the glacial isostatic adjustment is accounted for using model values we further confirm the consistency of our slr results with the vertical crustal uplift of the region observed by the global positining system gps which manifests ice mass loading unloading thus the slr data series constitute a continuous benchmark for the time history of the greenland ice mass changes for over two decades

depositional history and sequence stratigraphy of the precambrian cambrian boundary stratotype section chapel island formation southeast newfoundland abstract facies relationshps in the vendian to lower cambrian chapel island formation of southeast newfoundland are used to establish a sequence stratigraphic framework for this important boundary stratotype section the formation consists of five members of sandstone mudstone and minor limestone deposited in a variety of shoreline to shelf environments peritidal sandstone and shale units in member 1 are overlain by sandstone and silstone deltaic and shelf deposits of member 2 these make up a transgressive system tract in which small scale changes in relative sea level are superimposed on autocyclic deltaic processes the thickness 400 m of nearshore and inner shelf sediments resulted from high sediment accumulation rates which for member 2 nearly kept pace with subsidence upper member 3 and member 4 consist of inner shelf mudstone and peritidal limestone that were deposited in a low energy oxygen stratified basin these deposits are arranged in three large scale shoaling cycles representing three foresteping parasequences of one highstand systems tract an extensive limestone bed at the tope of member 4 contains a sequence boundary associated with or shortly postdating development of this surface is a significant epeirogenic event that resulted in basin reorganization increased subsidence and progradation of a thick clastic sequence represented by member 5 the deposits of this upper member consist of an upward coarsening storm dominated shelf to shoreface succession of sandstone and silstone deposits of nearly identical character are also found in new brunswick and suggest that these sediments and the underlying sequence boundary could be significant for interregional correlation global correlation of the paleobathymetric curve developed for the chapel island formation is considered unfeasible given the long history of epeirogenic movements during the vendian and early cambrian in this region

fine grained versus coarse grained wave ripples generated experimentally under large scale oscillatory flow abstract wave ripples were generated in a wave tunnel under large scale oscillatory flow orbital diameter 1 4 5 m using two different grain sizes very fine sand and coarse sand the geometry of bed configurations that were produced varied strongly as a function of grain size small anorbital ripples wavelengths 10 cm heights 5 cm these results support the hypothesis advanced by leckie 1988 that large waves generate markedly different stratigraphic signatures in fine grained and coarse grained sediment

sequence stratigraphy of the upper oligocene lower miocene of eastern jylland denmark role of structural relief and variable sediment supply in controlling sequence development the upper oligocene lower miocene succession in eastern jylland can be subdivided into three sequences a c from older to younger deposited on and around the ringkobing fyn high the development of the sequences reflects a complex interaction between eustatic sea level changes physiography and variable sediment supply superimposed on this frequent storms promoted longshore sediment transport and the development of spit systems adjacent to structural highs as a consequence sequence boundaries and flooding surfaces are not always expressed as portrayed in conventional sequence models sequence boundaries or flooding surfaces may only be marked by subtle changes in depositional environment that can only be revealed by careful integration of sedimentological observations with palynological data the influence of the topography resulted in the development of brackish water basins that were sufficiently large to permit the deposition of hummocky cross stratified sands with muds these deposits are overlain by clean hummocky and swaley cross stratified sands that were deposited in a fully marine high energy environment this evolution from mud rich storm influenced sediments to sand dominated shoreface sediments resulted from a rise in sea level and was not the result of shoreface progradation and downstepping during a sea level fall in addition to the topographic control on sequence development sediment supply to the study area changed significantly during the deposition of the three sequences initially the basin was sediment starved favouring the formation of glaucony rich sediments the sediment input gradually increased and the influence of structural highs and lows became less significant with time consequently both sequence boundaries and flooding surfaces are characterized by more conventional features in the younger part of the succession where a basinward displacement of the shoreline resulted in thick lowstand delta deposits

test of the predictability of the pi method for recent large earthquakes in and near tibetan plateau five large earthquakes of m 7 0 based on the magnitude scale of the china earthquake networks center occurred in and near the tibetan plateau during 2008 2014 including the wenchuan m8 0 earthquake on may 12 2008 bjt in this paper the tibetan plateau was chosen to be the study region and calculating parameters of pattern informatics pi method with grid of 1 1 and forecasting time interval of 8 years were employed for the retrospective study according to the previous studies for m7 earthquake forecasting the sliding step of forecasting interval was 1 year and the hotspot diagrams of each forecasting interval since 2008 were obtained year by year the relationships among the hotspots and the m 7 0 earthquakes that occurred during the forecast intervals were studied the predictability of pi method was tested by verification of receiveroperating characteristic curve roc and r score the results show that the successive obvious hotspots occurred during the sliding forecasting intervals before four of the five earthquakes while hotspots only occurred in one forecasted interval without successive evolution process before one of the five earthquakes which indicates that four of the five large earthquakes could be forecasted well by pi method test results of the predictability of pi method by roc and r score show that positive prospect of pi method could be expected for long term earthquake forecast

grace measurements of mass variability in the earth system monthly gravity field estimates made by the twin gravity recovery and climate experiment grace satellites have a geoid height accuracy of 2 to 3 millimeters at a spatial resolution as small as 400 kilometers the annual cycle in the geoid variations up to 10 millimeters in some regions peaked predominantly in the spring and fall seasons geoid variations observed over south america that can be largely attributed to surface water and groundwater changes show a clear separation between the large amazon watershed and the smaller watersheds to the north such observations will help hydrologists to connect processes at traditional length scales tens of kilometers or less to those at regional and global scales

the offshore quaternary sediment bodies of the english channel and its western approaches after a short review of present day surficial sediments on the sea floor of the english channel and its western approaches this paper summarises recent results on the present quaternary sandy accumulations tidal bank systems based on sea floor imaging very high resolution seismic surveys and a few piston cores the english channel a typical funnel shaped tidal shelf is presently starved of terrigenous sediments most of mobile sediments at the sea floor are autochthonous either skeletal carbonates or siliciclastic sands reworked from old littoral deposits or incised valley fills three zones are considered 1 the central and western central channel which is a bedload parting zone characterised by a pebbly lag making up the sole of the quaternary sediments throughout the shelf area 2 the eastern channel a flood dominated area characterised by medium to fine siliciclastic sands mainly of aeolian periglacial origin 3 the western approaches an ebb dominated area with a polygenic sediment cover characterised by coarse carbonate rich gravelly to muddy sands of marine to glaciomarine origin with a diachronous faunal content these sediments are sourced by reworking of a former littoral barrier or incised valley fills the seismic stratigraphy of quaternary sediment accumulations 10 50 m points to the predominant control of tidal dynamics together with the general interplay between the channel morphology and the sea level story the thickest deposits in the eastern channel and western approaches are built up into bank systems whereas the interpretation of the active eastern channel banks finds a general agreement the moribund banks in the western approaches i e the southern celtic banks remains under debate owing to the lack of long cores in our hypothesis both systems were built up during the last post glacial sea level rise the celtic banks would represent the tidal transgressive systems tract whereas the eastern channel banks correspond to the highstand systems tract the architecture of both bank systems is studied from two examples the bassure de baas bank in the eastern channel and the kaiser bank in the western approaches both examples show transgressive features the bassure de baas exhibits from base to top an estuarine mouth barrier a wave erosion surface a shoreface bank and finally a classic tidal bank by contrast the kaiser bank consists of the offshore reworking of fully marine deposits its base would correspond to the amalgamation of the last glacial sea level fall with a strong tidal ravinement surface from base to top the bank underwent tidal bar accretion very large dune field aggradation perched channels incision storm erosion and deposition

late pleistocene barrier island development reconstructed from genetic classification and timing of erosional surfaces paleo tokyo bay japan abstract formative processes of a retrogradational barrier island system and associated transgressive erosional surfaces are reconstructed from the upper pleistocene kioroshi formation developed in paleo tokyo bay japan the kioroshi formation provides high quality sedimentary records of a preserved barrier island system three volcanic ash beds intercalated in the formation provide a high resolution chronostratigraphic framework the barrier island system of the kioroshi formation developed in a glacio eustatically forced sea level cycle during oxygen isotope stages 6 to 5e in the early stage of the transgression paleo tokyo bay was non barred and was exposed to the pacific ocean affected by open ocean wave processes shoreface erosion in such a non barred environment developed a wave ravinement surface rs1 rs1 overlies incised valley fill deposits formed in the earliest stage of the transgression and is overlain by shoreface deposits that are further overlain by embayment deposits such as lagoonal and flood tidal delta deposits formed during succeeding barrier development during the later stage of the same transgression associated with the formation and landward migration of the barrier chain tidal currents in tidal inlet and flood tidal deltas became active and a tidal ravinement surface trs was formed trs is developed on the base of tidal inlet and flood tidal delta deposits furthermore shoreface erosion on the open ocean side of the barrier chain eroded underlying embayment deposits and formed a secondary wave ravinement surface rs2 a chronostratigraphic surface in embayment deposits defined by a volcanic ash bed intersects trs and is eroded by rs2 this relationship together with associated facies architecture indicates diachroneity of the formation of these marine erosional surfaces associated with the retrogradational barrier island system

the western grand banks of newfoundland transgressive holocene sedimentation under the combined influence of waves and currents abstract the surficial sediments on the western grand banks of newfoundland have been reworked from older deposits primarily late wisconsinan glacial and glaciomarine sediments during the post glacial sea level fall and holocene rise winnowed medium to coarse sands and lag gravels that are generally less than 0 5 m thick chracterize the areas above the lowstand elevation at 110 to 120 m the holocene sediments which have accumulated in the deeper interbank channels isolated basins and on the upper continental slope are thicker and consists of the fine sands and muds that were removed from the banks the deposits below the lowstand elevation coarsen upward because little deposition occured during the sea level rise in general the holocene succession becomes thicker and finer grained to the south active sediment movement occurs at all depths less than about 110 m wave ripples composed of sandy gravel form to depths in excess of 100 m in response to long period 15 s surface waves but the predominant bedforms consist of current generated sand ribbons megaripples and sandwaves which exhibit unidirectional migration azimuths toward the southwest even though the storm current directions are highly variable and the maximum sediment transport rates are directed toward the east or southeast the bedform orientation and resultant transport are instead parallel to the southerly and southwesterly storm currents which occur during the prolonged post storm spin down period and to the weak 1 labrador current and the orbital motion associated with the largestwaaves thus the interaction of the oceanic current and wave orbital motion with the directionally variable strom currents is responsible for the consistent orientation of the current generated bedforms and for the distribution of holocene deposits

storm deposits and storm generated coarse carbonate breccias on a pelagic outer shelf south east basin france uppermost jurassic limestones of the south east basin france are organized into four facies associations that were deposited in four distinct zones 1 peritidal lagoonal limestones 2 bioclastic and reefal limestones 3 pelagic lime mudstones 4 lime mudstones calcarenites coarse breccias calcarenite deposits of zone 4 exhibit sedimentary structures that are diagnostic of deposition under wave induced combined flow in subzone 4a both vertical and lateral transitions from lime mudstone calcarenite to breccia indicate in situ brecciation under wave cyclic loading breccias were produced by heterogeneous liquefaction of material previously deposited on the sea floor deposits in subzone 4a record relatively long periods 400 kyr of sedimentation below wave base alternating with periods of deposition under wave induced currents and periods of in situ deformation in this zone storm waves were attenuated by wave sediment interaction and wave energy was absorbed by the deformation of soft sediment with reference to present day wave attenuation water depths in this zone ranged between 50 and 80 m landwards of the attenuation zone in zone 3 storm waves were reduced to fair weather wave heights storm wave base was not horizontal and became shallower landwards as a consequence water depth and wave energy were not linearly related on a small area of the seaward edge of subzone 4a cobbles were removed by traction currents and redeposited in subzone 4b there they formed a 100 m thick wedge which prograded over 3 km and was built up by the stacking of 5 to 20 m thick cross stratified sets of coarse breccia this wedge records the transport and redeposition of cobbles by a high velocity unidirectional component of a combined flow the increase in flow velocity in a restricted area is proposed to result from flow concentration in a channel like structure of the downwelling in the gulf formed by the basin in more distal subzone 4c the hydrodynamic effect of wave induced currents was quasi permanent and brecciation by wave sediment interaction occurred only episodically this indicates that seawards of the attenuation zone hydrodynamic storm wave base was deeper than mechanical storm wave base uppermost jurassic carbonates were deposited and soft sediment deformed on a hurricane dominated ramp of very gentle slope and characterized by a zone of storm wave degeneration located seawards of a zone of sedimentation below wave base

storms in the deep tempestite and beach like deposits in pelagic sequences jurassic subbetic south of spain abstract fine peloidal to coarse oolitic bioclastic grainstones with hummocky cross stratification hcs occur interbedded in jurassic pelagic lime mudstone successions subbetic betic ranges southern spain these strata were deposited in pelagic troughs and swells away from continental areas in the southern iberian paleomargin of the western tethys selected examples presented in this study include a coarse oolitic grainstones encased in pelagic marls holding characteristics similar to the ridge berm swash zone of modern beaches b peloid grainstones with hcs interbedded with radiolarite marls deposited on the flanks of volcanic guyots the interbedded lime muds and marls contain filaments sponge spicules and radiolarians c peloid bioclastic radiolarians filaments etc grainstone beds with hcs interbedded with pelagic lime muds d crossbedded peloidal skeletal saccocoma grainstones with hcs and wave ripples on top interbedded with pelagic mudstones and wackestones with abundant bioturbation and ammonites ammonitico rosso facies all the examples here presented share 1 grainstone beds are interbedded with pelagic mudstones and marls 2 grainstone components were reworked by oscillatory flows superimposed to unidirectional tractive flows unidirectional ripple lamination and hcs 3 components either derived from shallow water environments e g ooids or produced in pelagic conditions e g radiolarians saccocoma filaments peloids etc were reworked by high energy processes unrelated to surface storm waves 4 internal waves iws propagating along a pycnocline and breaking against a sloping surface are the best candidates to induce the sedimentary structures and sediment organization that characterize these grainstone beds coarser sediments trapped at the breaker zone form sediment accumulations similar to the sediments caught by the littoral fence in the surface beach this scenario evidences the hcs not to be necessarily linked to the surface storms but to the pycnocline bathymetry solving the problem of having hcs in pelagic zones where the storm and hurricanes wave action can be considered out of context

time variability of the earth s gravity field hydrological and oceanic effects and their possible detection using grace the grace satellite mission scheduled for launch in 2001 is designed to map out the earth s gravity field to high accuracy every 2 4 weeks over a nominal lifetime of 5 years changes in the gravity field are caused by the redistribution of mass within the earth and on or above its surface grace will thus be able to constrain processes that involve mass redistribution in this paper we use output from hydrological oceanographic and atmospheric models to estimate the variability in the gravity field i e in the geoid due to those sources we develop a method for constructing surface mass estimates from the grace gravity coefficients we show the results of simulations where we use synthetic grace gravity data constructed by combining estimated geophysical signals and simulated grace measurement errors to attempt to recover hydrological and oceanographic signals we show that grace may be able to recover changes in continental water storage and in seafloor pressure at scales of a few hundred kilometers and larger and at timescales of a few weeks and longer with accuracies approaching 2 mm in water thickness over land and 0 1 mbar or better in seafloor pressure

time variable gravity from grace first results eleven monthly grace gravity field solutions are now available for analyses we show those fields can be used to recover monthly changes in water storage both on land and in the ocean to accuracies of 1 5 cm of water thickness when smoothed over 1000 km the amplitude of the annually varying signal can be determined to 1 0 cm results are 30 better for a 1500 km smoothing radius and 40 worse for a 750 km radius we estimate the annually varying component of water storage for three large drainage basins the mississippi the amazon and a region draining into the bay of bengal to accuracies of 1 0 1 5 cm

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

grace detects coseismic and postseismic deformation from the sumatra andaman earthquake 1 we show that spherical harmonic sh solutions of the gravity recovery and climate experiment grace are now of sufficient quality to observe effects of co seismic and post seismic deformation due to the rupture from the mw 9 3 sumatra andaman earthquake on december 26 2004 and its companion nias earthquake mw 8 7 on march 28 2005 the improved ggm 03 sh level 2 solutions and improved filtering methods provide estimates with spatial resolution comparable to earlier estimates from range rate level 1 grace data the gravityfield disturbance extends over 1800 km along andaman and sunda subduction zones and changes with time following events gravity changes may be due to afterslip viscoelastic relaxation or other processes associated with dilatation satellite gravity measurements from grace provide a unique new measure of deformation and post seismic processes associated with major earthquakes especially in areas which are primarily oceanic citation chen j l c r wilson b d tapley and s grand 2007 grace detects coseismic and postseismic deformation from the sumatraandaman earthquake geophys res lett 34 l13302

plant wax δd values record changing eastern mediterranean atmospheric circulation patterns during the 8 2 kyr b p climatic event abstract throughout the holocene the climate of the mediterranean region has been strongly influenced by variability in the atmospheric circulation of the high and low latitudes a prominent example for such holocene climate perturbations is the 8 2 kyr b p climatic event reorganization of northern hemisphere atmospheric circulation patterns resulted in variations of temperature and precipitation distribution across the mediterranean the effects of changing high and low latitude atmospheric circulation on mediterranean climate in relation to the 8 2 kyr b p climatic event are however not well understood here we present a high resolution record of stable hydrogen isotope composition of plant wax n alkanes dwax across the 8 2 kyr b p climatic event from the tenaghi philippon peat deposit ne greece in order to characterize patterns of precipitation and changes in atmospheric circulation in the eastern mediterranean region our record reveals pronounced changes in dwax that correlate closely with previously published palynological data a long term decline in dwax values characterizes the lower part of the section the 8 2 kyr b p climatic event itself is connected to two distinct positive dwax excursions a minor shift in dwax around 8 2 kyr b p and a major shift in dwax between ca 8 1 and 8 0 kyr b p the upper part of the section shows a progressive trend towards higher dwax values we link shifts in dwax to changes in mediterranean air mass trajectories supplying precipitation to ne greece caused by variations in the relative contributions of northerly derived d depleted moisture and southerly derived d enriched moisture possible control mechanisms for alternating air mass trajectories include changes in the influence of the siberian high and differences in the influence of the african and asian monsoon circulation on anticyclonic conditions in the mediterranean region as well as regional inflow of moist air masses from the aegean sea

geophysical interpretation of observed geocenter variations geocenter variations are caused by mass redistribution within the earth system especially the atmosphere oceans and continental water using surface pressure fields and soil moisture and snow depth fields of the ncep ncar climate data assimilation system i cdas i 1 we estimate contributions from variations in atmospheric surface pressure and continental water storage to the earth s geocenter center of mass variation in addition sea surface anomalies determined by the topex poseidon altimeter are used to investigate geocenter variations resulting from ocean mass redistribution these sea surface height data were corrected using a simplified steric model a comparison with observed geocenter variations derived from lageos 1 and 2 satellite laser ranging data indicates that the atmosphere oceans and continental hydrological cycle all provide significant contributions at different frequencies geocenter variations estimated in this paper are in reasonably good agreement with results given by dong et al 1997 for atmospheric and ocean contributions but not for the estimates of continental hydrological contributions

lithofacies and depositional dynamics of golden oolite bathonian kachchh mainland gujarat india abstract the golden oolite member of the patcham formation consisting of 84 m thick alternate sequence of limestones and mudstone are well exposed in the jhura dome kachchh mainland gujarat petrographic study of limestones reveals four types of microfacies oolitic fossiliferous grainstone a 1 fossiliferous intraclastic grainstone a 2 sandy fossiliferous grainstone a 3 and pebbly fossiliferous grainstone a 4 the microfacies normally form microfacies assemblages with calcareous mudstone b 1 and are stacked vertically in ascending order as a 1 a 3 a 1 b 1 a 4 b 1 and a 2 b 1 the assemblage a 1 a 3 is characterised by interbedding of moderately to thickly bedded hard and compact golden coloured oolitic fossiliferous grainstone and sandy fossiliferous grainstone exhibiting small scale low angle planar cross beddings it contains well preserved bioclast assemlage a 1 b 1 is distinguished by rhythmic alternations of earthy concretionary calcareous mudstone and moderately to very thickly bedded golden coloured oolitic fossiliferous grainstone showing ripple bedding abundant bioclast and reworked intraclasts whereas assemblage a 4 b 1 exhibits rhythmic alternations of bioturbated earthy concretionary calcareous mudstone and moderately to thickly bedded pebbly fossiliferous grainstone assemblage a 2 b 1 is characterised by earthy bioturbated calcareous mudstone containing thin uneven beds of fossiliferous intraclastic grainstone having micritic intraclast and microfossils the study of lithofacies suggests two main depositional processes for the formation of golden oolite 1 the high energy physical sedimentation from current flows during transgression characterized by irregular to sharp nature of basal contact of each cycle abundance of well preserved bioclasts and reworked intraclasts and large scale ripple bedding 2 settling of fines from suspension during fair weather period as distinguished by homogenous fine grained interbeds of mudstone in the sequence the transition of facies from a 1 a 3 to a 2 b 1 marks deepening upward event during bathonian period from shallow inner shelf to calcareous mud dominated outer shelf the energy condition was very high during deposition of the lower and middle part a 1 a 3 and a 1 b 1 assemblage whereas low to very low as revealed by abundance of bioturbated calcareous mudstone b 1 with episodic interruption of moderate to high energy storm event depositing a 4 pebbly fossiliferous grainstone microfacies during the upper part a 4 b 1 and a 2 b 1 assemblage of the sequence

alaskan mountain glacial melting observed by satellite gravimetry abstract we use satellite gravity measurements from the gravity recovery and climate experiment grace as an indication of mass change to study potential long term mountain glacial melting in southern alaska and west canada the first 3 5 yr of grace monthly gravity data spanning april 2002 november 2005 show a prominent glacial melting trend in the mountain regions around the gulf of alaska goa grace observed surface mass changes correlate remarkably well with available mass balance data at gulkana and wolverine two benchmark glaciers of the u s geological survey usgs although the grace signals are smaller in magnitude in addition terrestrial water storage tws changes estimated from an advanced land surface model show significant mass loss in this region during the same period after correcting for the leakage errors and removing tws contributions using model estimates we conclude that grace observed glacial melting in the goa mountain region is equivalent to 101 22 km 3 yr which agrees quite well with the assessment of 96 35 km 3 yr based on airborne laser altimetry data and is consistent with an earlier estimate based on the first 2 yr of grace data this study demonstrates the significant potentials of satellite gravity measurements for monitoring mountain glacial melting and regional climate change

high frequency depositional sequences of the upper part of the kazusa group a middle pleistocene forearc basin fill in boso peninsula japan abstract a middle pleistocene forearc basin fill of the upper part of the kazusa group is represented by slope to shelf sediments and is well exposed in the boso peninsula of japan the slope to shelf sediments are a northeasterly prograded clastic wedge as much as 700 m in maximum thickness and include many volcanic ash layers mapping of volcanic ash layers together with the interpretation of depositional facies permits identification of stratal terminations and spatial and temporal variations of depositional environments this allows sequence stratigraphic analysis of the slope to shelf sediments of the upper part of the kazusa group six depositional sequences were identified in the upper part of the kazusa group by correlating each depositional sequence with the stable oxygen isotope sea level index integrated with the age framework for the upper part of the kazusa group ca 0 72 0 45 ma periodicity of the depositional sequences of the upper part of the kazusa group can be estimated at about 20 000 to 90 000 years the high frequency depositional sequences are interpreted to be a result of interaction between high sedimentation rate in the forearc basin and high rate of glacio eustatic sea level changes during the middle pleistocene

depositional setting and early diagenesis of the dinosaur eggshell bearing aren fm at bastus late campanian south central pyrenees the late cretaceous aren fm exposed north of bastus in the tremp basin south central pyrenees preserves an excellent record of dinosaur eggs laid in a marine littoral setting different from other cases reported in literature at the bastus site the preferential nesting ground was original beach sand the coastal deposits of aren fm can be grouped into four facies assemblages representing respectively shoreface beachface beach ridge plain and backbarrier lagoon environments shoreface deposits include fine to coarsegrained hybrid arenites and subordinate quartz dominated conglomerates with ripple structures of wave and wave current origin beachface deposits are mainly storm beach conglomerates but parallel laminated foreshore arenites locally occur backbarrier lagoon deposits comprise of washover sandy conglomerates that grade laterally into sandy lime mudstones biomicrites and marls beach ridge sediment wherein the bulk of dinosaur eggs and eggshell debris occurs predominantly is a reddish hybrid arenite that has undergone a complex early diagenetic evolution including marine and meteoric cementation followed by soil development the reddish arenites overlie wave dominated shoreface deposits and in places pass laterally into lagoonal deposits they originally formed shore ridges that became stabilized during progradational episodes by pedogenesis beach ridge sensu otvos e g 2000 beach ridges definitions and significance geomorphology 32 83 108 which also affected the dinosaur eggs the eggshell bearing beach ridge arenites are typically preserved at the top of parasequences forming the systems tracts of a third order sequence thick packages of this facies resulted from aggradation of barrier beach ridge deposits whose preservation below surfaces of transgressive erosion was favoured by incipient lithification

internal waves vs surface storm waves a review on the origin of hummocky cross stratification hummocky cross stratification hcs is considered a diagnos tic structure of surface storm activity at the shoreface offshore transition however the origin of hcs is still debated laboratory experiments have not yet reproduced it and direct observations on the continental shelves do not exist most hydrodynamic interpretations invoke pure oscilla tory flows unidirectional dominated combined flows and oscillatory dominated flows but they all share the assump tion of hcs to reflect the combined action of surface storm waves and related currents within this context of uncertain ties internal waves gravity waves propagating along the pycnocline provide an alternative mechanism to explain the origin of hcs internal waves breaking on the shelf create episodic high turbulence events and induce upslope and downslope currents as well as oscillatory flows at the depth where the pycnocline intersects the sea floor in this scenario both the oscillatory and the unidirectional components needed for hcs to form are not necessarily linked to surface storm waves but can occur at various depth as far and near there is a pycnocline where internal waves can form

time variable gravity from space and present day mass redistribution in theearth system abstract since 2002 the us german grace gravity recovery and climate experiment mission has been providing a precise survey of earth s time variable gravity field with unprecedented temporal and spatial sampling grace time variable gravity fields provide a means of measuring temporal and spatial variations of mass redistribution within the earth system the grace mission has launched a new era in studying a series of geophysical problems ranging from deep earth structure to tracking mass redistribution on and near the surface of the earth grace has greatly improved understanding of mass redistribution in various compartments of the climate system atmosphere oceans terrestrial water and cryosphere in this review we use examples to show how grace has fundamentally enriched a number of fields including but not limited to the global water cycle and land hydrology mass balance of polar ice sheets and mountain glaciers ocean mass and global sea level change and solid earth geophysics

slope shelf nearshore depositional sequences with transgressive conglomerate in a miocene backarc and arc junction setting central japan abstract several third order slope shelf nearshore depositional sequences are found in the middle to late miocene aoki and ogawa formations in the southern part of the northern fossa magna region central japan each depositional sequence consists of a transgressive systems tract varying in thickness from several tens of centimetres to about 10 m a falling stage systems tract several tens of metres in thickness and a highstand systems tract 20 80 m thick the highstand systems tract and falling stage systems tract are bounded by the regressive surface of marine erosion each depositional sequence mainly consists of coarse grained sediments the materials of the transgressive conglomerate beds were derived from the gravelly foreshore and upper shoreface by transgressive shoreface erosion the thin and conglomeratic transgressive systems tract indicates that these slope shelf nearshore sequences were deposited on the steep slope area under a rapid transgression therefore these sequences were formed in response to excess sediment supply and a rapid rise in relative sea level at an active margin of the backarc side of the arc trench system

the lower permian wasp head formation sydney basin high latitude shallow marine sedimentation following the late asselian to early sakmarian glacial event in eastern australia the lower permian wasp head formation early to middle sakmarian is a 95 m thick unit that was depos ited during the transition to a non glacial period following the late asselian to early sakmarian glacial event in eastern australia this shallow marine sandstone dominated unit can be subdivided into six facies associa tions i the marine sediment gravity flow facies association consists of breccias and conglomerates deposited in upper shoreface water depths ii upper shoreface deposits consist of cross stratified conglomeratic sand stones with an impoverished expression of the skolithos ichnofacies iii middle shoreface deposits consist of hummocky cross stratified sandstones with a trace fossil assemblage that represents the skolithos ichnofacies iv lower shoreface deposits are similar to middle shoreface deposits but contain more pervasive bioturba tion and a distal expression of the skolithos ichnofacies to a proximal expression of the cruziana ichnofacies v delta influenced lower shoreface offshore transition deposits are distinguished by sparsely bioturbated carbo naceous mudstone drapes within a variety of shoreface and offshore deposits trace fossil assemblages repre sent distal expressions of the skolithos ichnofacies to stressed proximal expressions of the cruziana ichnofacies impoverished trace fossil assemblages record variable and episodic environmental stresses possibly caused by fluctuations in sedimentation rates substrate consistencies salinity oxygen levels turbidity and other physio chemical stresses characteristic of deltaic conditions vi the offshore transition offshore facies association con sists of mudstone and admixed sandstone and mudstone with pervasive bioturbation and an archetypal to dis tal expression of the cruziana ichnofacies the lowermost 50 m of the formation consists of a single deepening upward cycle formed as the basin transitioned from glacioisostatic rebound following the asselian to early sak marian glacial to a regime dominated by regional extensional subsidence without significant glacial influence the upper 45 m of the formation can be subdivided into three shallowing upward cycles parasequences that formed in the aftermath of rapid possibly glacioeustatic rises in relative sea level or due to autocyclic progra dation patterns the shift to a parasequence dominated architecture and progressive decrease in ice rafted de bris upwards through the succession records the release from glacioisostatic rebound and amelioration of cli mate that accompanied the transition to broadly non glacial conditions

wave formed coarse grained ripples and their relationship to hummocky cross stratification abstract wave formed coarse grained ripples cgr form in water depths ranging from 3 to 160 m on transgressive surfaces in upper and lower shoreface sediments and in finer grained offshore transition deposits cgr have crest spacings of 0 25 3 0 m with amplitudes of 5 35 cm internal stratification is rarely preserved but where present crossbeds dip en echelon away from the ripple crest and individual laminae feather out away from the crest waves that form cgr commonly have wavelengths on the order of 2 5 m with periods of 8 to 14 sec these are not large storm events especially on a geological scale cgr commonly occur in close association laterally and vertically with hummocky cross stratification it is postulated that if sediment is medium to very coarse grained sand or pebbly sand then two dimensional cgr will be formed from oscillatory or oscillatory dominant flow if however sediment is very fine to fine grained sand then three dimensional hummocky cross stratification will be formed the wave conditions under which cgr form are similar to those which would form hummocky cross stratification it is only the grain size that is different reported and calculated wave conditions for hummocky cross stratification are almost identical to those for cgr modern cgr crests trend parallel to the local shoreline and bathymetry as such ancient ripple crests are a useful tool for basin reconstruction

postseismic signature of the 2004 sumatra earthquake on low degree gravity harmonics 1 we perform an extensive analysis of the low degree gravity field harmonics measured by the grace mission in order to find a signature of the postseismic relaxation following the 2004 sumatra earthquake we find a statistically significant perturbation in the secular trend of low degree zonal coefficients jl in correspondence of the 2004 sumatra earthquake and a similar perturbation but with weak associated statistical significance also in the nonzonal coefficients technical features and results of such analysis are discussed the time dependent postseismic evolution of harmonic coefficients is modeled for various asthenosphere viscosity values using a theoretical model of global postseismic deformation the observed change in secular trend is found to be consistent with our modeling results but it cannot be used to discriminate between viscosities a forward modeling of the perturbations to time dependent zonal variation rates following the sumatra earthquake for various asthenospheric viscosities is provided as a result an evident signature of the sumatra earthquake on l time series is expected for asthenospheric viscosity values below 1018 pa s therefore long term l time histories from satellite laser ranging will be able to put constraints on the asthenosphere viscosity if such a signature is evidenced from data or at least put lower limits if no significant perturbation will be observed

independent patterns of water mass anomalies over australia from satellite data and models the gravity recovery and climate experiment grace products allow the quantification of total water storage tws changes at global to regional scales however the quantity measured by grace represents mass signals integrated over vertical columns requiring their separation into their original sources such a separation is vital for australia for which grace estimates are affected by leakage from the surrounding oceans the independent component analysis ica method that uses higher order statistics is implemented here to separate grace derived water storage signals over the australian continent from its surrounding oceans covering from october 2002 to may 2011 the performance of ica applied to grace is then compared to the ica of watergap global hydrology model wghm and the ica of the australian water resources assessment awra system to study the influence of rainfall variability on the derived independent patterns use is made of tropical rainfall measuring mission trmm data set from january 2000 to may 2011 implementing ica on grace tws showed a remarkable improvement in separating the continental hydrological signals from the surrounding oceanic anomalies which was not achievable using a conventional principle component analysis reconstructing the continental tws changes using only those independent components of grace that were located over the continent showed a high correlation with wghm tws and awra tws mass concentrations over the oceans and particularly s2 semi diurnal aliased pattern were separated as independent modes correlation analysis between the independent components of grace and climate teleconnections showed that the mass anomalies over the northern ocean gulf of carpentaria and north eastern parts of australia were significantly correlated with the el nino southern oscillation while those over south and south eastern parts of australia were mainly linked to the indian ocean dipole

stratigraphy sedimentology and physical volcanology of the henik group central ennadai rankin greenstone belt northwest territories canada late archean paleogeography of the hearne province and tectonic implications abstract extensive areas of the hearne and rae provinces are underlain by archean metavolcanic and metasedimentary rocks in the rae province supracrustal sequences with prominent continental to shallow water quartz arenites have been interpreted by others as rift and passive margin deposits in the hearne province to the southeast the ennadai rankin greenstone belt is exposed in an area ca 700 200 km forming the second largest greenstone belt in canada it comprises mainly greenschist facies grade mafic and felsic volcanic siliciclastic chemogenic and volcaniclastic rocks stratigraphic sedimentologic and physical volcanologic data based on 1 50 000 scale mapping in the central part of the belt indicate deposition in a subaqueous mafic volcanic plateau slope basin system that was well removed from a continental influence water depth was below storm wave base as indicated by preservation of delicate lamination in pelitic and iron formation units absence of features suggestive of subaerial exposure oscillatory flow or tidal currents and lack of interfingering rocks that could represent laterally adjacent shelf coastal or continental environments reconnaissance level regional geologic and geochronologic data indicate an overall pattern of supracrustal deposition in the hearne province consisting of a large mafic volcanic plain isolated felsic volcanic centres with lenses and belts of deep water sedimentary rocks at least two speculative yet testable tectonic models are consistent with the inferred paleogeography for both the rae province is considered to be the western continental hinterland to the ensimatic hearne province the rae and hearne provinces may record late archean continental extension sea floor spreading oceanic volcanic arc growth diachronous back arc spreading and collapse and arc continent collision with thrusting of oceanic rocks on to attenuated rae crust alternatively the hearne province may represent northwestward accretion of multiple volcanic arc trench pairs

low degree spherical harmonic influences on gravity recovery and climate experiment grace water storage estimates we estimate terrestrial water storage variations using time variable gravity changes observed by the gravity recovery and climate experiment grace satellites during the first 2 years of the mission we examine how treatment of low degree gravitational changes and geocenter variations affect grace based estimates of basin scale water storage changes using independently derived low degree harmonics from earth rotation eop and satellite laser ranging slr observations grace based water storage changes are compared with estimates from nasa s global land data assimilation system gldas results from the 22 grace monthly gravity solutions covering the period april 2002 to july 2004 show remarkably good agreement with gldas in the mississippi amazon ganges ob zambezi and victoria basins combining grace observations with eop and slr degree 2 spherical harmonic coefficient changes and slr observed geocenter variations significantly affects and apparently improves the estimates especially in the mississippi ob and victoria basins

distribution and origin of subaqueous dunes on the shelf of japan abstract subaqueous dunes are found on the shelf around the japanese islands mainly in the straits between the islands some of the dunes are formed by ocean currents and others by tidal currents combined flows also produce shoreparallel coarse grained bands and medium dunes on the inner shelf the dynamics of these bedforms was examined using repeated observations of bedforms and by comparing the hydraulic conditions required to form the bedforms with the existing oceanographic conditions the study indicates that most of bedforms are active but the volumes of sediment transported are too small to form the sand bodies which underlay the large dunes seismic records show these sand bodies occur on the erosional surfaces formed after the last glacial maximum it is suggested that most of the sand bodies were formed during the postglacial transgression

estuarine barrier island to strand plain sequence and related ravinement surface developed during the last interglacial in the paleo tokyo bay japan abstract recognition of sequence boundaries and transgressive surfaces i e ravinement surfaces rs is now known to be of great importance in stratigraphy the sedimentary features of deposits immediately above a transgressive surface are well exposed in the upper pleistocene kioroshi formation of the kanto plain in central japan the formation comprises mainly coastal and shallow marine deposits estuarine barrier island and the strand plain systems which accumulated along a wavedominated coast in the late pleistocene i e the last interglacial to last glacial period the kioroshi formation is bounded above and below by sequence boundaries that formed in the lowstand periods correlative to the glacial periods of oxygen isotope stages 4 and 6 respectively a significant transgressive surface that was formed by landward migration of barrier islands during the transgressive interval the ravinement surface rs is found within the deposits of the upper shelf environment this ravinement surface is characterized by the exotic nature of the overlying sediment veneer pebbles shells and scattered mud clasts which is poorly sorted the rs shows a very flattened erosional surface in the shore parallel sense and the gradient of the surface in shore normal sense is calculated as 0 0021 where the syndepositional tectonic movement is revised the rs commonly cuts through the lower sequence boundary however in the places where the river or tidal channel valleys incised the valley filling sediment shows a deepening upward sequence recognized as a transgressive systems tract and the rs can be clearly distinguished from the lower sequence boundary

low degree gravitational changes from grace validation and interpretation 1 we examine low degree gravitational variations c21 s21 and c20 observed by the gravity recovery and climate experiment grace satellites during the first 2 years of this gravity mission the grace observations are compared with independent estimates from accurately measured earth rotational changes and predictions from atmospheric oceanic and hydrological models the 18 grace monthly gravity solutions covering the period april 2002 to march 2004 show strong seasonal variability in the c21 s21 and c20 time series and generally agree with earth rotation derived changes and geophysical model estimates in particular for s21 and c20 the reason for the poorer agreement between the grace results and the earth rotation derived estimates for c21 is unclear we demonstrate that the omission of the ocean pole tide in the grace data processing does have significant effects on the estimated c21 and s21

the gravity recovery and climate experiment mission overview and early results 1 the grace mission is designed to track changes in the earth s gravity field for a period of five years launched in march 2002 the two grace satellites have collected nearly two years of data a span of data available during the commissioning phase was used to obtain initial gravity models the gravity models developed with this data are more than an order of magnitude better at the long and mid wavelengths than previous models the error estimates indicate a 2 cm accuracy uniformly over the land and ocean regions a consequence of the highly accurate global and homogenous nature of the grace data these early results are a strong affirmation of the grace mission concept

a highstand oolitic sequence and associated facies from a late triassic lake basin south west england high energy lake shoreline carbonate sequences are rarely documented in the geological record however one example occurs in the upper triassic mercia mudstone group mmg of southern britain the mmg is one of a number of thick non fossiliferous mudstone deposits associated with north atlantic mesozoic rift basins the origin of the mmg mudstones is the subject of current debate with marine playa lacustrine and alluvial aeolian models having been proposed shoreline features have been documented from the northern margin of the basin but the rarity of such features elsewhere in the mmg has led many workers to doubt a lacustrine origin for the mudstones wave dominated lake shoreline deposits have been recognized in several sections from the southern basin margin in the clevedon area of the bristol channel in south west england these deposits provide evidence for the development of a sizeable perennial to semi perennial hypersaline lake in which the mmg mudstones accumulated shoreline sediments overlie alluvial stream and sheet flood deposits and pass from transgressive gravel conglomerate beach units with bioclasts influenced by shore normal waves deposited under semi humid conditions to lower gradient highstand oolitic sands affected by more varied wave approach deposited under progressively more arid conditions which culminated in lowstand oolitic strand plain deposits overlain by a playa mudflat unit shoreline deposits record a simple shallowing upward transgressive highstand lowstand sequence however a change from a reflective transgressive to dissipative highstand shoreline is believed to represent a climatically induced change in prevailing wind direction shoreline features recognized in the mmg are similar to those of recent playa lacustrine basins of the western united states ooids display a variety of size fracture and dissolution features in addition to beachrock fabrics suggesting that they were originally composed of radial aragonite similar to modern ooids from the great salt lake utah

iceberg rafting and scouring in the early permian shoalhaven group of new south wales australia evidence of heinrich like events abstract this paper describes multiple layers of ice rafted debris and an ice scour structure in early permian marine strata within the shoalhaven group of the sydney basin new south wales australia strata were deposited on a high latitude glacially influenced continental margin during the final stages of late palaeozoic glaciation between 277 and 260 ma poorly sorted ice rafted debris forming layers up to 1 25 m thick is common within inner to outer shelf and continental slope facies of the shoalhaven group more than 120 layers can be identified these are argued to record the enhanced delivery of debris by icebergs drifting north from marine based antarctic ice margins deformation structures in associated sediments are interpreted as iceberg scours and ice keel turbates associated glendonites record early diagenesis of organic rich sediment and bottom water temperatures close to freezing a speculative hypothesis relates layers of ice rafted debris within the shoalhaven group to multiple episodes of accelerated calving at the margins of a marine based early permian ice sheet in east antarctica these events may be analogous to late pleistocene heinrich events when huge armadas of icebergs were released from the marine based laurentide ice sheet and triggered abrupt changes in ocean circulation and climate similar forcing may have characterized the early permian ice ocean system regardless of the climatic significance of ice rafted layers this is the first time such facies have been documented in the pre pleistocene literature to date few ice scour structures and no ice keel turbates have been reported

paralic parasequences associated with eocene sea level oscillations in an active margin setting trihueco formation of the arauco basin chile abstract the eocene trihueco formation is one of the best exposed successions of the arauco basin in chile it represents a period of marine regression and transgression of second order duration during which barrier island complexes developed on a muddy shelf the strata are arranged in classical shoaling upward parasequences of shoreface and beach facies capped by coal bearing back barrier lagoon deposits these fourth order cycles are superimposed upon third order cycles which caused landward and seaward shifts of the coastal facies belts the final punctuated rise in sea level is represented by shelf mudrocks with transgressive incised shoreface sandstones relative sea level oscillations as revealed in the stratigraphy of the trihueco formation show a reasonable correlation with published eocene eustatic curves

estimating geocenter variations from a combination of grace and ocean model output 1 in this study we estimate a time series of geocenter anomalies from a combination of data from the gravityrecoveryandclimateexperiment grace satellitemissionandthe outputfromoceanmodels amatrixequationisderivedrelating totalgeocentervariations to the grace coefficients of degrees two and higher and to the oceanic component of the degree one coefficients we estimate the oceanic component from two state of the art ocean models results are compared to independent estimates of geocenter derived from other satellite data such as satellite laser ranging and gps finally we compute degree one coefficients that are consistent with the processing applied to the grace level 2 gravity field coefficients the estimated degree one coefficients can be used to improve estimates of mass variability from grace which alone cannot provide them directly

sedimentology of rocky shorelines 4 coarse gravel lithofacies molluscan biofacies and the stratigraphic and eustatic records in the type area of the pleistocene hulopoe gravel lanai hawaii abstract during the pleistocene the south flank of lanai was the site of repeated erosion and deposition as a consequence of glacio eustasy superimposed on tectono isostasy throughout this time terrigenous and bioclastic gravel was generated along mainly rocky shorelines gravelly sediment was deposited in topographically low areas of the shoreface and inner shelf that later were uplifted isostatically the sedimentary lithofacies and biofacies in these deposits are distinctive but they represent a deposystem and suite of environments that hitherto have not been studied systematically these unrecognised circumstances have fuelled controversies about the nature and significance of the hulopoe gravel most notably the claim that it represents a mega tsunami deposit the hulopoe gravel in its type area displays a lithofacies succession that encompasses a complete disconformity bounded transgressive regressive cycle on a sand poor rocky shoreline this succession incorporates not only a distinctive vertical assemblage of rocky shoreline litho and biofacies but also internal disconformities that record episodes of erosion and non deposition during shoreline migration repetition of the lithofacies succession imparts overall stratigraphic order to the hulopoe gravel four unconformity bounded transgressive regressive cycles correspond to eustatic highstands of oxygen isotope stages 5 and 7 superimposed on continuing tectono isostatic uplift driven by growth of the island of hawaii this study of the hulopoe gravel demonstrates that the sedimentary record of mixed volcaniclastic carbonate depositional systems developed on rocky shorelines of tropical and subtropical oceanic island coasts can be preserved this record may include depositional products of both transgressive and regressive shorelines although tsunami and giant submarine landslides are known to occur in the hawaiian islands deposits and features that result from tsunami inundation above the shoreline such as might be expected from landslide related mega tsunami have not been recognised in the type area of the hulopoe gravel rocky palaeoshoreline records on oceanic volcanic islands may yield oceanographic and climatic clues that complement data obtained from other palaeoshoreline types

latest quaternary paleoseismology and evidence of distributed dextral shear along the mohawk valley fault zone northern walker lane california the dextral slip mohawk valley fault zone mvfz strikes northwestward along the eastern margin of the sierra nevada in the northern walker lane geodetic block modeling indicates that the mvfz may accommodate 3 mm yr of regional dextral strain implying that it is the highest slip rate strike slip fault in the region however only limited geologic data are available to constrain the system s slip rate and earthquake history we mapped the mvfz using airborne lidar data and field observations and identified a site near sulphur creek for paleoseismic investigation at this site oblique dextral normal faulting on the steep valley margin has created a closed depression that floods annually during spring snowmelt to form an ephemeral pond we excavated three fault perpendicular trenches at the site and exposed pond sediment that interfingers with multiple colluvial packages eroded from the scarp that bounds the eastern side of the pond we documented evidence for four surface rupturing earthquakes on this strand of the mvfz oxcal modeling of radiocarbon and luminescence ages indicates that these earthquakes occurred at 14 0 ka 12 8 ka 5 7 ka and 1 9 ka the mean 4 kyr recurrence interval is inconsistent with slip rates of 3 mm yr these rates imply surface ruptures of more than 10 m per event which is geologically implausible for the subdued geomorphic expression and 60 km length of the mvfz we propose that unidentified structures not yet incorporated into geodetic models may accommodate significant dextral shear across the northern walker lane highlighting the role of distributed deformation in this region

storm features of siliciclastic shelf sedimentation in the mid cretaceous epeiric seaway of northern australia abstract late aptian to early cenomanian strata were deposited in a large epeiric seaway which covered much of the northern australian landmass during mid cretaceous time the seaway stretched from the carpentaria basin in the north to the eromanga basin in the south during this period siliciclastic sediments accumulated on a gently sloping epeiric shelf which formed the western margin of the carpentaria basin the shelf maintained a relatively similar configuration throughout the mid cretaceous with water depths rarely exceeding 50 m and the seafloor was apparently within the influence of storm waves over much of the area the shelf was storm and wave dominated and most early formed or fair weather sedimentary structures were destroyed or extensively modified during episodic storms storm features include hummocky cross stratification shelly lags erosional conglomeratic lags gutter casts lenticular micro hummocky sand beds megaripples characteristic low diversity and opportunistic ichnofacies various styles of wave ripple lamination and poorly preserved event beds most storm influenced units are preserved as coarsening and shallowing upwards facies successions which aggraded during high relative sea level and prograded during falling relative sea level some of these successions were subsequently eroded during further cyclic fluctuations of relative sea level

sedimentary structures sorby and the last decade henry clifton sorby pioneered in the last century the description and especially the hydrodynamic interpretation of sedimentary structures together with their use as palaeocurrent indicators research completed since the last syntheses were published a decade ago shows that work along these lines continues to be necessary and relevant particularly as regards the physical explanation of structures and to present significant challenges and opportunities perhaps the most pressing needs are for a better understanding of 1 bedforms in gravels silts and carbonate sediments 2 tidal and especially sand wave bedding 3 hummocky and swaley cross stratification and 4 soft sediment and dewatering structures in turbidites many sedimentary structures present a little exploited opportunity to quantify process rates and define short time periods from the rock record

ensemble prediction and intercomparison analysis of grace time variable gravity field models precise measurements of the earth s time varying gravitational field from the nasa deutsches zentrum fur luft und raumfahrt gravity recovery and climate experiment grace mission allow unprecedented tracking of the transport of mass across and underneath the surface of the earth and give insight into secular seasonal and subseasonal variations in the global water supply several groups produce these estimates and while the various gravity fields are similar differences in processing strategies and tuning parameters result in solutions with regionally specific variations and error patterns this study examined the spatial temporal and spectral variations between the different gravity field products and developed an ensemble gravity field solution from the products of four such analysis centers the solutions were found to lie within a certain analysis scatter regardless of the local relative water height variation and the ensemble model is clearly seen to reduce the noise in the gravity field solutions within the available scatter of the solutions

holocene sediment lithofacies and dispersal systems on a storm dominated back arc shelf margin the east coromandel coast new zealand abstract holocene sediment lithofacies and dispersal systems on the east coromandel shelf new zealand are mainly characterised by an accommodation dominated regime in which autochthonous siliciclastic sediments were reworked through erosional shoreface retreat during the post glacial marine transgression 12 0 6 5 ka stabilisation of sea level at its present position ca 6 5 ka initiated onshore reworking of the autochthonous deposits into fine grained regressive barrier and shoreface sands while coarser sands remained offshore to form an erosional lag inner shelf deposit modern episodes of shoreface erosion rework fine and coarse autochthonous sands offshore and northwards into very large 0 5 2 5 m 250 1500 m submarine dunes the submarine dunes are similar in form to sand ridges on the north american atlantic shelf but with crests striking perpendicular to both the shoreline and generating flows allochthonous siliciclastic lithofacies are also important aspects of east coromandel shelf sedimentation and are transported offshore from infilled estuary systems to form very fine grained upper shoreface and muddy mid shelf sands the regional geology has a strong influence on shelf lithofacies and dispersal systems off the east coromandel coast southern shelf regions are associated with deep back arc basins which have formed major late cenozoic depocentres for sediments sourced from the taupo volcanic zone further north a shallow volcanic platform extends out across the shelf and forms a barrier to any large scale along shelf dispersal of sediments consequently lithofacies in northern shelf regions tend to be highly variable and reflect local catchment lithologies

influence of the ancestral sweetgrass arch on sedimentation of the lower cretaceous bootlegger member north central montana abstract in north central montana the bootlegger member of the upper lower cretaceous blackleaf formation is well exposed near great falls and at one locality in the sweetgrass hills in both areas bootlegger strata comprise four stratigraphic successions in the great falls study area each succession consists of an upward coarsening shoaling package of interbedded very fine sandstone and shale grading upward into fine to medium sandstone abruptly overlain by a transgressive erosion surface and capped in many places by a conglomeratic transgressive lag deposit the stacking of these successions is attributed to episodic changes of relative sea level probably related to episodic reactivation of the ancestral sweetgrass arch during episodes of arch uplift accommodation space was reduced a d caused the bootlegger shoreline to prograde eastward subsequently because of arch subsidence and or the ongoing basinwide eustatic rise the shoreline migrated westward erosion associated with transgressive shoreface retreat was most intense near the crest of the arch as a result in the western study area which lies above the arch crest successions are thin and typically consist only of inner shelf strata lithofacies 1 strata deposited in shallower environments were removed mainly by later transgressive erosion by contrast in the eastern area farther from the arch crest the upward shoaling part of each succession is more completely preserved at the end of bootlegger time however movement of the arch either ceased or simply could no longer keep pace with the eustatic ri e consequently the shoreline continued to transgress westward and only fossiliferous silt and mud accumulated in a distal shelf environment this marked a eustatic drowning and termination of rhythmic bootlegger sedimentation

neoarchaean c 2 58 ga halite casts implications for palaeoceanic chemistry possibly the most extensive and best preserved archaean halite casts yet discovered occur in the c 2 58 ga upper black reef and basal oaktree formations transvaal supergroup in mpumalanga province south africa halite casts are isolated on bedding planes range in size from c 1 mm to 20 mm and have cubic dumbbell and triangular shapes as well as hopper like pyramidal hollows on cube faces some of the casts display distinct hopper shapes characteristic of halite crystals the halite cast bearing pavements are developed within silicified mudstone interbedded with siltstone or stromatolitic dolomite associated sedimentary structures pointing to subaerial exposure include adhesion ripples and warts desiccation and prism cracks rill marks and tepee structures halite cast bearing beds are interpreted as supratidal flat or sabkha deposits the presence of isolated casts and hopper shaped crystals suggests that halite resulted from displacive growth within the sediment from supersaturated residual brines after mudstone deposition absence of any indication of the former presence of gypsum or anhydrite supports previous contentions that the neoarchaean ocean was deficient in sulphate or contained a high bicarbonate to calcium ratio such that with progressive evaporation most calcium was consumed before the gypsum stability field was reached the association of halite and carbonate in the upper black reef and basal oaktree formations constrains the palaeolatitude of the transvaal basin at 2 58 ga to subequatorial 10 30

optimized smoothing of gravity recovery and climate experiment grace time variable gravity observations 1 high degree and high order spherical harmonics of time variable gravity fields observed by the gravity recovery and climate experiment grace gravity mission are dominated by noise we develop two smoothing methods that suppress these high degree and high order errors with results superior to more commonly used gaussian smoothing these optimized smoothing methods considerably improve signal to noise levels of grace terrestrial water storage estimates relative to residual signal and noise over the oceans and show significantly better spatial resolution and lower leakage error on the basis of analysis using an advanced land surface model the equivalent spatial resolution from these optimized smoothing estimates is about 500 km compared to the roughly 800 1000 km gaussian smoothing that is required to suppress high degree noise in the grace fields

the magnitude of late paleozoic glacioeustatic fluctuations a synthesis a comprehensive literature review shows that the magnitude of eustatic fluctuations varied throughout the carboniferous and permian and that at least eight distinct phases can be recognized facies juxtapositions in carbonate successions and erosional relief in clastic successions indicate that glacioeustatic fluctuations of 20 25 m and occasionally as much as 60 m took place throughout the early mississippian tournaisian a widely recognized glacial period middle mississippian mid chadian through holkerian shallow marine carbonate and clastic successions indicate that eustatic fluctuations were 10 25 m a decrease that matches well with the paucity of coeval glacial deposits late visean asbian through mid brigantian glacioeustatic fluctuations of 10 50 m record the initial phases of ice accumulation in advance of the widespread mid carboniferous glacial event the latest mississippian earliest pennsylvanian mid brigantian through langsettian was a time of widespread glaciation and strata of this age commonly exhibit evidence of glacioeustatic fluctuations of as much as 40 100 m although middle pennsylvanian duckmantian through asturian glacial deposits are present in eastern australia paleovalley depths suggest that coeval glacioeustatic fluctuations were less than 40 m glacioeustatic fluctuations of as much as 100 120 m have been widely reported from late pennsylvanian earliest permian stephanian through mid sakmarian successions in north america an increase that corresponds to the growth of large ice sheets across much of gondwana and the accumulation of ice in the northern hemisphere incision and facies juxtaposition in early middle permian mid sakmarian through kungurian successions in eastern australia indicate that glacioeustatic fluctuations of 30 70 m occurred during the waning stages of major glaciation erosional relief in paleoequatorial carbonates and the presence of coeval glacial deposits in australia suggests that eustatic fluctuations of 10 60 m occurred during the final stages of glaciation in the middle to late permian roadian through capitanian but the modest size of most of these fluctuations makes it difficult to isolate the glacioeustatic signature this review demonstrates that far field cyclic successions record changing glacial conditions in gondwana that the magnitude of glacioeustatic fluctuations was directly related to the volume of glacial ice that carboniferous permian glacioeustasy was more variable than previously recognized and that generalizations from short temporal intervals are probably not representative of the late paleozoic ice age as a whole although any attempt to quantify the magnitude of ancient eustatic changes is based on caveats and assumptions this review incorporates the results of over 100 published papers on the topic in an attempt to minimize the errors inherent in any one study

sequence stratigraphy and carbonate siliciclastic mixing in a terminal proterozoic foreland basin urusis formation nama group namibia abstract superb three dimensional exposures of mixed carbonate and siliciclastic strata of the terminal proterozoic urusis formation in namibia make it possible to reconstruct cross basin facies relations and high resolution sequence stratigraphic architecture in a tectonically active foreland basin six siliciclastic facies associations are represented coastal plain upper shoreface middle shoreface lower shoreface storm influenced shelf and pebble conglomerate siliciclastic shoreface facies pass seaward into and interfinger with facies of an open carbonate shelf four carbonate facies associations are present mid shelf shelf crest outer shelf and slope facies are arranged hierarchically into three scales of unconformity bounded sequences small scale sequences are one to tens of meters thick and span a few thousand years they consist of shelf carbonate with or without shoreface siliciclastic facies near the bottom medium scale sequences are tens of meters thick and span a few hundred thousand years they consist of shoreface siliciclastic facies in their lower parts which grade upward and pass seaward into shelf carbonate large scale sequences are tens to hundreds of meters thick and span 1 to 2 million years they are identified by widespread surfaces of exposure abrupt seaward shifts in shoreface sandstone patterns of facies progradation and retrogradation and shoreline onlap by medium scale sequences patterns of carbonate siliciclastic mixing distinguish tectonic from eustatic controls on the evolution of large scale sequences characteristics of eustatically controlled large scale sequences include 1 basal unconformities and shoreface sandstone that extend across the shelf to the seaward margin 2 retrograde carbonate and siliciclastic facies belts that onlap the shoreline together symmetrically during transgression and 3 upper shoreface sandstone that progrades seaward during highstand in contrast tectonically controlled sequences feature 1 basal erosion surfaces and upper shoreface sandstone that are restricted to near the landward margin and pass seaward into zones of maximum flooding and 2 asymmetric stratigraphic development characterized by landward progradation of carbonate from the seaward margin coincident with backstepping and onlap of the shoreline by siliciclastic facies a two phase tectonic model is proposed to account for the stratigraphic asymmetry of tectonically controlled sequences increased flexural bending during periods of active thrust loading caused submergence of the seaward margin and uplift of the landward margin rebound between thrusting episodes flattened the basin gradient and submerged the landward margin causing expansion of carbonate facies from the seaward margin and simultaneous transgression of the landward margin although the two phase model should apply to single lithology successions deposited in active foreland basins the mixing of carbonate and siliciclastic facies provides a particularly sensitive record of tectonic forcing the sensitivity may be sufficient for medium and small scale sequences to record higher frequency variations in flexural warping

sedimentology of an early silurian carbonate ramp the manitoulin formation southern ontario the manitoulin formation is a pervasively dolomitized lower silurian carbonate unit that was deposited in the michigan basin and locally in the appalachian basin the formation reaches a maximum thickness of 11 1 m in southern ontario and can be subdivided into eight facies and four regionally correlatable facies assemblages owing to the relatively continuous transition of shallow to deeper water facies from the northern to southern portions of the study area the manitoulin formation is interpreted as having formed on a carbonate ramp with a southerly component of dip our study suggests that the algonquin arch which is transected by the outcrop belt did not significantly influence deposition or separate the michigan and appalachian basins depending on its location on the ramp the manitoulin formation shows evidence of varying degrees of episodic storm events alternating with fair weather processes such as wave shoaling sediment reworking and bioturbation apart from bioturbation these fair weathe

environmental changes and shallow marine fossil bivalve assemblages of the lower cretaceous miyako group ne japan abstract we reconstructed the environmental changes recorded in the lower cretaceous miyako group via facies analysis and delineated the relationship between depositional facies and the occurrence of diverse marine invertebrate macrofossils the miyako group consists of deposits from alluvial bay head delta bay head delta front central bay and lower shoreface to inner shelf depositional settings fossil bivalve assemblages responded to shifts in these sedimentary environments we defined three fossil bivalve assemblages from the central bay and lower shoreface to inner shelf deposits the assemblages in the inner shelf and central bay deposits are clearly different even though they occur within similar depositional facies this contrast in assemblages results from environmental differences between closed and open settings this interpretation is supported by the occurrence of stenohaline crinoids we defined a fourth bivalve assemblage in a tsunami deposit intercalated within the bay head delta front deposits it consists of polygenic allochthonous shells some that were derived from an estuarine environment or the shallow seafloor and others that were torn from small reefs