a physical explanation of the relation between flank uplifts and the breakup unconformity at rifted continental margins rift flank uplifts and the breakup or postrift unconformity are characteristic features of many rifted passive or atlantic type continental margins but are not predicted as primary features of simple lithospheric stretching models the explanations that have been proposed for their origin remain controversial either because they call upon special circumstances or because they are difficult to test plane strain finite element models are used in this paper to explore the dynamics of lithospheric necking during rifting and rupture the results agree with the conceptual interpretation that uplift of the rift boundaries to form flank mountains and uplift of the basin responsible for the breakup unconformity are related consequences of regional isostatic compensation of mass that is redistributed during the necking and rupture phases although the amplitudes of these uplifts depend on the model parameter values the relations between and relative signs of these two effects appear to be fundamental the explanation we propose may have been missed in recent studies because there has been a tendency to concentrate on kinematic stretching models which assume local isostatic equilibrium through out the rifting process such an approach is predicated on the assumption that the lithosphere has an insignificant strength or flexural rigidity during extension which is not true if our explanation is correct

role of crustal stretching on subsidence of the continental crust abstract the principal areas of subsidence of the continental crust are wide intracontinental basins and passive continental margins in many intracontinental basins crustal extension amounts to only a few percent and is unable to explain their subsidence as shown for the timan pechora pre caspian and west texas basins the deep black sea and south caspian basins are underlain by highly attenuated continental crust having velocities in the 7 km s range that shows no evidence for significant extension in passive margins upper crustal extension ranges between 10 and 40 whereas the lower crust is attenuated by 2 3 times e g campos basin north biscay margin large discrepancy between upper crustal stretching and lower crustal attenuation is seen in the crustal configuration of many intracontinental grabens e g baikal and dniepr prypyat basins only in highly extended areas such as the basin and range province and the east china rift system does crustal stretching account for the observed crustal thinning the observed discrepancy between upper extension and crustal thinning across intracontinental rifts and passive margins and particularly in some wide intracontinental basins suggests that crustal stretching alone cannot account for the subsidence of these basins phase transformations in the lower crust probably facilitated by the presence of hydrous fluids can cause rapid 1 ma as well as long term 200 1500 ma upward displacement of the moho discontinuity resulting in high amplitude subsidence of the crust in areas of crustal extension this mechanism can overprint subsidence induced by thermal relaxation of the lithosphere the case of the black sea and south caspian basins shows that density increase of the lithosphere can also occur independently of crustal stretching

intraplate stresses and dynamical aspects of rifted basins abstract intraplate stresses play a important role during the syn and post rift evolution of sedimentary basins deviations from long term thermal patterns of post rift subsidence as well as the development of unconformities within rifted basins reflect to a large extent the temporal fluctuations of the regional stress fields in the lithosphere it appears that incorporation of intraplate stresses in dynamical models for basin development together with a quantification of the role of petrological changes in the crust lithosphere system can explain some of the observed shortcomings of thermal models of post rift basin subsidence late neogene accelerations in tectonic subsidence in the deeper parts of rifted basins in the northern atlantic and mediterranean regions could reflect a change in the level of intraplate stress over large areas of the globe non thermal contributions to the subsidence record affect estimates of crustal extension and consequently influence the depth at which hydrocarbon source rocks enter the maturity window stress induced changes in basement topography have also important consequences for the budget of fluid flow in the deeper parts of the sediment fill of the rifted basins as well as on the dynamics of diapirism

the effect of lithospheric phase transitions on subsidence of extending continental lithosphere abstract a new simple model for sedimentary basin formation which combines both stretching and phase transitions occurring together in the lithosphere is proposed and two important aspects in sedimentary basin formation are addressed 1 the explanation of the domal uplift preceding rifting and 2 the ability of the model to explain the contradiction between a small amount of crustal stretching and the large amount of thermal subsidence without the need to invoke differential stretching between the crust and mantle relationships for synrift initial and thermal post rift subsidence are derived the model predicts that extension of continental lithosphere could produce synrifting uplift up to a threshold amount of extension and then subsidence for greater extension three dimensionless parameters quantify the contribution of the phase transition to the subsidence history 1 the clapeyron slope normalized to the initial geothermal gradient 2 the ratio of depth of phase transition to the thickness of the lithosphere and 3 the ratio of density effect due to phase transition to the change in density due to thermal expansion an evaluation of these parameters has been carried out by using thermodynamical data for the garnet spinel transition for upper mantle rocks our simple model shows that by including the effects of lithospheric phase transition in existing stretching models of sedimentary basin formation we can obtain an extra significant parameter controlling the subsidence and the entire extensional tectonics of such basins

uplift and extension at the gulf of suez indications of induced mantle convection reconstruction of tectonic movements since the initiation of the gulf of suez rift indicates that there has been 25 27 km of extension the uplift bordering rift indicates that lithosphere heating greatly exceeds that producible by uniform lithosphere extension i propose that small scale convection induced by the rifting augments the heating introduced by extensional rifting and produces the broad uplifts flanking the rift

geodynamics of rifting and implications for hydrocarbon habitat abstract rifting activity is probably mainly governed by frictional forces exerted on the base of the lithosphere by the convecting sub lithospheric upper mantle combined with deviatoric tensional stresses developing over upwelling branches of the asthenospheric convection system and by far filed stresses controlling the interaction of lithospheric plates moving relative to each other mantle plumes rising from the deep mantle do not appear to be a major driving force of rifting therefore it is questioned whether a distinction between active and passive rifts is still justified lithospheric extension triggers by decompression partial melting of the lower lithosphere and upper asthenosphere magmatic processes contribute materially to thinning of the subcrustal lithosphere and probably also of the lower crust this could explain the frequently observed discrepancy between upper crustal extension by faulting and lower crustal attenuation as defined by refraction and deep reflection seismic data the duration of the rifting stage of palaeorifts and passive margins is highly variable depending on plate interaction crustal separation can be achieved after as little as 7 ma and as much as 280 ma of rifting activity the availability of crustal discontinuities does not appear to play a significant role in the time required for crustal separation to be achieved the structural style of rifts is controlled by the physical state of the lithosphere the mode and amount of its extension and the lithological composition of pre and syn rift sediments subsidence of rift basins is controlled by the balance between isostatic adjustment of the crust to lithospheric stretching and uplift induced by mechanical and thermal attenuation of the subcrustal lithosphere post rift basin subsidence is mainly governed by the decay of rift induced thermal anomalies densification of the lower crust and intra plate stresses provide overprinting effects in view of this it is unlikely that quantitative analyses of post rift basin subsidence give a direct measure of lithospheric extension tectonically active rifts palaeorifts and passive margin basins contain major hydrocarbon provinces their hydrocarbon charge can rely exclusively on pre rift syn rift or post rift sedimentary sequences or a combination thereof maturation of source rocks can be achieved during the syn and or post rift stage of basin evolution during rifting conductive and convective heat transfer accounts for elevated geothermal gradients these play an important role in the maturation of pre and syn rift source rocks thermal gradients decrease asymptotically during the post rift stage

plate reorganization a cause of rapid late neogene subsidence and sedimentation around the north atlantic subsidence analysis of wells in the central north sea and labrador grand banks and oft the west greenland scotian shelf and united states atlantic margin shows distinct quantitative stratigraphic correlation patterns of circum north atlantic sites a significant departure from the overall decrease in subsidence for the pliocene occurs in many wells when the rate is found to have increased one or more orders of magnitude from oligocence miocene rates wells were selected along transects from shore to basin to find if relative basin position is influenced by differential basin subsidence although stratigraphic resolution is not detailed more basinward sites experienced up to four times larger subsidence rates in the late neogene than in the oligocene miocene with a peak in the pliocene wells at the basin edge experienced much less subsidence or showed uplift the observations are consistent with a rapid change of intraplate stress at the cause for this observed transition in neogene subsidence major reorganizations of spreading direction and rate occurred during the pliocene along the entire atlantic spreading system possibly in conjunction with more global changes in plate motions we propose that the associated changes in intraplate stress caused the excess margin subsidence relative uplift along basin edges is consistent with this mechanism of relative movement and may explain apparent eustatic changes in sea level

algorithm for sea surface wind retrieval from terrasar x and tandem x data a geophysical model function gmf which is denoted by xmod2 is developed to retrieve sea surface wind field from x band terrasar x tandem x ts x td x data in contrast to the previously developed xmod1 xmod2 consists of a nonlinear gmf and thus it depicts the difference between upwind and downwind of the sea surface backscatter in x band synthetic aperture radar sar imagery by exploiting 371 collocations with in situ buoy measurements that are used as the tuning data set together with analysis wind model results the retrieved ts x td x sea surface wind speed using xmod2 shows a close agreement with buoy measurements with a bias of 0 32 m s a root mean square error rmse of 1 44 m s and a scatter index si of 16 0 further validation using an independent data set of 52 cases shows a bias of 0 17 m s an rmse of 1 48 m s and an si of 17 0 comparing with buoy measurements to apply xmod2 to ts x td x data acquired at hh polarization we validate three x band sar polarization ratio models that were tuned using ts x dual polarization data by comparing the retrieved sea surface wind speed with buoy measurements

subsidence history crustal structure and thermal evolution of the valencia trough a young extensional basin in the western mediterranean the valencia trough is an extensional basin that began rifting during the late oligoceneearly miocene yet it is located within a region of compression between the european and african plates seismic reflection seismic refraction well gravity and geoid data have been used to determine the relative importance of extensional and compressional processes in controlling the structure and evolution of the trough although the trough appears symmetric on bathymetric maps seismic and gravity and geoid data indicate a fundamental asymmetry in its deep crustal and upper mantle structure two dimensional flexural backstripping techniques have been used to estimate the total amount of crustal stretching along a transect of the trough between the catalan coastal ranges and mallorca there is good agreement between the predicted depth to the mono based on a stretching model and the seismically constrained depth beneath the catalan margin but poor agreement beneath mallorca the seismic moho beneath mallorca can be explained by a model in which the crust was modified by the flexural effects of thrust fold loading geoid data suggest that the differences in the crustal structure between the two margins extend into the upper mantle the catalan margin is characterized by a thermal and mechanical boundary which marks the transition between cold unstretched lithosphere and hot thin lithosphere while mallorca is located above a broad region of lithospheric thinning the subsidence history and amount of crustal thinning in the catalan margin resemble that of typical atlantic type nonvolcanic margin however a narrow transition zone 60 km the lack of any evidence for a conjugate margin and the absence of oceanic crust suggest fundamental differences in the way that extensional processes may occur in convergent plate settings

tectonics and global change inferences from the late cenozoic subsidence and uplift patterns in the atlantic mediterranean region summary quantitative subsidence analysis for a number of rifted basins in the northern atlantic mediterranean region provides evidence for rapid phases of plioquaternary subsidence the observed acceleration in tectonic subsidence occurs after a phase of general quiescence in subsidence in these basins and deviates from predictions of stretching models the latter indicate a decay of subsidence with time after mesozoic tertiary basin formatioh and a slow tectonic subsidence in plio quaternary times a possible explanation for the observed patterns of anomalous subsidence could be an increase in the level of intraplate compression in the northern atlantic region intraplate stress changes in the plio quaternary are related to the dynamics of african eurasian collision processes and a reorganization of spreading directions in the atlantic possibly reflecting a plate reorganization of global nature it seems that the plio quaternary record reflects a period of increased levels of neotectonic activity interplaying with periods of de glaciation stress induced topography in the onshore parts of continental margins coupled with the stress induced subsidence in the offshore deeper parts of the basins could have contributed to recent phases of uplift in fennoscandia augmenting the uplift induced by glacial unloading estimates of ice thicknesses are directly inferred from the observed uplift ignoring other driving mechanisms whereas topography plays a crucial role in the dynamics of glaciation it is therefore important to quantdy the interplay of rapid tectonic uplift and subsidence phases with climatic effects during the plio quaternary

intraplate stresses a new tectonic mechanism for fluctuations of relative sea level stress variations in the lithosphere of a few hundred bars can explain the major part of the seismostratigraphic record at passive margins and intracratonic basins however to induce apparent sea level fluctuations with magnitudes greater than 50 m changes in stress level of more than 1 kbar are required these must be related to major reorganizations at convergent plate boundaries fragmentation of plates or collision processes specific rapid falls in the vail et al curves can be associated quantitatively with particular plate tectonic reorganizations of lithospheric stress fields the seismostratigraphic record may provide a new source of information on paleo stress fields to be correlated with results of independent numerical modeling of intraplate stresses

thermal history and extension of the lithosphere in the mannar basin and realization its hydrocarbon potential offshore sri lanka abstract data on the structure of the sedimentary blanket and the composition of its rocks measurements of deep temperatures and vitrinite reflectance published in the open press were used for the numerical 1 d reconstructions of the thermal evolution of the mannar basin and the history of its tectonic subsidence near wells pearl 1 dorado north pseudo mannar deep and barracuda analysis of variations in the basin s tectonic subsidence and published geophysical data on the modern depth of the moho boundary made it possible to numerically estimate the degree of stretching of the basin s lithosphere at different stages of its evolution our analysis shows that a significant part of the lithosphere extension occurred before the start of the formation of the basin s sedimentary cover the moderate lithosphere extension with amplitude 1 15 1 25 accompanied the thermal activation of the basin lithosphere during the second stage of the basin rifting in the late cretaceous our modeling suggests a more moderate history of changes in the thermal regime of the basin s lithosphere and lower degree of maturity and realization of hydrocarbon potential in sedimentary sections of the pearl 1 dorado north pseudo mannar deep and barracuda wells than those reconstructed numerically in recent studies of the mannar basin

the origin of sedimentary basins a status report from the task force of the international lithosphere program abstract better insights into the mechanisms of basin formation have a direct bearing on the predictive power of forward models for basin fill models that link flexure normal faulting and thrusting on a subbasin scale provide important constraints on the tectonic control of the sedimentary record enabling a quantitative comparsion with eustatic contributions to the basin architecture thus of special importance is the need to link processes with different spatial and temporal scales involved in the evolution of extensional and compressional basins by numerical modelling a new generation of basin modelling concepts and techniques is one of the main objectives of the task force origin of sedimentary basins of the international lithosphere program the focus of this work is on the quantification of the effects of the thermomechanical structure of the lithosphere and its interplay with regional and local stress changes other important developments include the step towards three dimensional modelling and the full integration of rapidly expanding fission track and other data sets to constrain vertical motions in basins as natural laboratories for the interactive testing and development of new basin modelling techniques a number of basins with high quality data from industry government and academia have been selected on the basis of specific testable problems

topography and geoid due to lithospheric mass anomalies summary a model of lithospheric thickness and a recent compilation of moho depths are used to compute the earth s isostatic surface topography and associated gravity anomalies the results are strongly influenced by the uncertainties in lithospheric depth and crustal density profiles the preferred models explain most of the observed topography and are highly correlated with observed gravity anomalies for harmonic degrees larger than 10 comparisons of our residual topography with geodynamical calculations of dynamic topography based on mantle circulation are rather poor

subsidence analysis and modelling of the roer valley graben se netherlands abstract the roer valley graben southeastern netherlands forms the most northern branch of the european cenozoic rift system sedimentary backstripping of exploration wells provides control on vertical tectonic motions during the complex post paleozoic geodynamic evolution of the area the roer valley graben evolved by repeated reactivation of permo carboniferous fracture systems at least three episodes of extension related subsidence are recorded these occurred during the late permian early triassic 255 240 ma the middle jurassic 168 165 ma and the late cenozoic 36 0 ma a late jurassic early cretaceous stretching phase is weakly inferred from incomplete data crustal stretching values calculated from the tectonic subsidence curves can account for the reflection seismic controlled crustal configuration of the roer valley graben area results demonstrate a close relationship between the roer valley graben and the basins in the north sea during the mesozoic in contrast the cenozoic evolution of the roer valley graben is independent from that of the north sea and is related to the development of the rhine graben

change in tectonic force inferred from basin subsidence implications for the dynamical aspects of back arc rifting in the western mediterranean abstract a method has been developed that allows temporal changes in tectonic force during rift basin formation to be inferred from observed tectonic subsidence curves and has been applied to the gulf of lions the provencal basin and the valencia trough in order to gain some understanding of the dynamical aspects of back arc basin rifting in the western mediterranean sea two distinct tectonic force regimes active at different times during the evolution of each of these back arc basins are identified the first which can be seen in both basins is characterized by tensional forces that gradually abate with time to vanish some 20 my after the onset of rifting the magnitude of tectonic force required to initiate the rifting process is significantly greater in the valencia trough than in the provencal basin subsequently the dynamic development of these back arc basins differs in the provencal basin there is a renewal of force with extensional deformation concentrated in the central part of the rift whereas in the valencia trough the second tectonic force regime is inferred to be one that causes compression that subsequently relaxes such temporal patterns of tectonic force are interpreted to be related to the causative driving processes allowing constraints to be placed on the transient interaction between the overriding and subducting plates in a back arc setting the models also allow inferences to be made about the rheological structure of the lithosphere a significant variation of initial crustal thickness is inferred for the provencal basin but not for the valencia trough in both basins a wet rheology is required in order to initiate rifting given currently accepted bounds on tectonic force magnitudes adoption of a dry rheology leads to insufficiently high strain rates for significant lithosphere extension in both cases

a thermodynamic model for subsolidus equilibria in the system caomgoal2o3sio2 this study integrates phase equilibrium and calorimetric data for the following phases in the cao mgo al2o3 sio2 system clinopyroxene orthopyroxene garnet fomente anorthite spinel kyanite sillimanite corundum and quartz the internally consistent data set includes mixing properties for clinopyroxene orthopyroxene and garnet solid solutions and enables calculation of any equilibrium involving the components of the above 10 phases under any desired p t conditions major conclusions of the study apart from the data set are 1 1 spinel appears to have an enthalpy of mg al exchange on the order of 20 kcal or more substantially above the calorimetrically measured value 2 2 caal2sio6 pyroxene has virtually complete al si disorder 3 3 enstatite has an enthalpy of formation from oxides at 1000 k of about 16840 cal mole substantially greater than the calorimetric value of 17620 340 cal 4 4 anorthite has about 0 6 cal k entropy of al si disorder 5 5 cmas garnets of between pyrope100 and pyrope80grossular20 composition have almost zero excess entropy 6 6 nonstoichiometry in clinopyroxene has a moderate but predictable influence on reaction boundaries in sio2 saturated compositions

lithospheric dynamics and the rapid pliocene quaternary subsidence phase in the southern north sea basin abstract we present stratigraphic modeling and quantitative analysis of the pliocene and quaternary subsidence of the southern north sea basin during the late pliocene well before the onset of quaternary glaciation the subsidence rate in the southern part of the north sea basin showed a ten fold increase relative to previous tertiary rates the high pliocene quaternary subsidence rate is consistent with the direction and state of the present intraplate stress field in northwest europe one possible consequence of the modern compressional stress field in northwest europe is reactivation of faulting in the central graben resulting in localized stretching and the development of pull apart basins alternatively the acceleration in late pliocene subsidence rates could be due to localized flexural downwarping of the lithosphere in the central graben caused by an increase in the level of intraplate compression both mechanisms succesfully predict the major characteristics of the overall quaternary subsidence history and stratigraphy gravity modeling suggests that the mechanism of localized stretching dominates the recent tectonostratigraphic evolution of the southern north sea

on a tectonic mechanism for regional sealevel variations abstract no satisfactory tectonic explanations have yet been offered for the apparent sealevel fluctuations of about 1 cm 1000 years and a magnitude of up to a few hundred meters that have been proposed by vail et al 1 we propose a mechanism that does appear to be able to explain these changes if horizontal stresses of the order of a few kilobars occur in the lithosphere and if changes in these stress fields occur on geological time scales the proposed model is one of an interaction between these stresses and the deflections of the lithosphere caused by sedimentary loading apparent sealevel changes of up to 100 m can be produced at the flanks of the sedimentary basins by this interaction the mechanism is most effective for young margins that are subject to rapid sediment loading by its nature the tectonic model can explain contemporaneous fluctuations in apparent sealevel in neighbouring depositional environments in principle it implies the possibility of regional correlations in different basinal settings

the role of lithospheric phase transitions on seafloor flattening at old ages abstract uplift of old ocean seafloor relative to the familiar t 1 2 curve is generally presumed to be a consequence of an additional heat source at the base of the oceanic lithosphere several geodynamical mechanisms have been invoked to explain this behavior we have taken a petrological rather than geodynamical approach and considered whether the causes of the flattening can be found within the conductive portion of the lithosphere where viscous creep is insignificant accordingly self consistent calculations of the phase assemblages of several candidate mantle compositions have been performed subject to the constraint of experimentally determined calorimetric measurements we have found that in general for temperatures below around 800 c and pressures greater than 10 kbar the phase change from spinel peridotite to garnet peridotite has a significantly negative clapeyron slope which could cause some amount of uplift of old seafloor the transition for representative thermal profiles should be depressed from about 35 km at 40 ma to 45 km at 160 ma since spinel peridotite is of lower density the net effect is to raise the seafloor topography the extent of the uplift which depends primarily on the al 2 o 3 content of the peridotite and on the effective thermal diffusivity of the lithosphere should be on the order of 140 220 m

zoned chondrules in semarkona evidence for high and low temperature processing at least 15 of the 10w feo chondrules in semarkona ll3 0 have mesostases that are concentrically zoned in na with enrichments near the outer margins we have studied zoned chondrules using electron microprobe methods x ray mapping plus quantitative analysis ion microprobe analysis for trace elements and hydrogen isotopes cathodoluminescence imaging and transmission electron microscopy in order to determine what these objects can tell us about the environment in which chondrules formed and evolved mesostases in these chondrules are strongly zoned in all moderately volatile elements and h interpreted as water calcium is depleted in areas ofvolatile enrichment titanium and cr generally decrease toward the chondrule surfaces whereas al and si may either increase or decrease generally in opposite directions to one another mn follows na in some chondru1es but not in others fe and mg are unzoned d h ratios increase in the water rich areas of zoned chondrules mesostasis shows cathodoluminescence zoning in most zoned chondrules with the brightest yellow color near the outside mesostasis in zoned chondrules appears to be glassy with no evidence for devitrification systematic variations in zoning patterns among pyroxene and olivine rich chondrules may indicate that fractionation oflow and high ca pyroxene played some role in ti cr mn si ai and some ca zoning but direct condensation ofelements into hot chondrules secondary melting oflate condensates into the outer portions of chondrules and subsolidus diffusion of elements into warm chondrules cannot account for the sub parallel zoning profiles ofmany elements the presence ofh20 or elemental abundance patterns zoning ofmoderately volatile elements and ca may have been produced by hydration ofchondrule glass without devitrification during aqueous alteration on the parent asteroid this could have induced structural changes in the glass allowing rapid diffusion and exchange of elements between altered glass and surrounding matrix and rim material calcium was mainly lost during this process and other nonvolatile elements may have been mobile as well some unzoned 10w feo chondrules appear to have fully altered mesostasis

the effects of the spinel garnet phase transition on the formation of rifted sedimentary basins summary we have examined the effects of the spinel garnet phase transition on subsidence of extensional sedimentary basins for a constant positive clapeyron slope dp dt the phase boundary moves downwards in the syn rift and upwards in the post rift phase for a non linear clapeyron curve dp dt 0 above 900 c and dp dt 0 below 900 c theory predicts for the reaction of the spinel garnet phase transition the direction of phase boundary movement is dependent on the stretching factor the position of the clapeyron curve and the lithospheric thickness a smaller syn rift and larger post rift subsidence are predicted for a deeper phase boundary and a thicker lithosphere the model with a non linear clapeyron curve is applied to the subsidence histories of a young extensional basin gulf of lion and an old continental margin eastern canada the observed syn rift uplift and the larger post rift subsidence can be reasonably explained by this model where the optimum depth of the phase boundary for eastern canada 90 km is consistent with the estimate from seismic observations and is larger than that for the gulf of lion 50 km the depth of the spinel garnet phase boundary is sensitive to the composition of mantle rocks and increases with the extraction of basaltic components from the lithosphere compatible with our result that the phase boundary is deeper for an older and thicker lithosphere thus the surface movement associated with the rifting for these areas may reflect the chemical evolution of the continental lithosphere

phase changes and thermal subsidence in intracontinental sedimentary basins summary a model of tectonic subsidence is developed to explain the late acceleration of subsidence observed in some intracratonic sedimentary basins the proposed mechanism combines the effect of thermal contraction of an initially hot lithosphere with the effect of a subcrustal phase transformation that moves under changing pressure and temperature conditions the subsidence following a sudden change in temperature at the base of the lithosphere is calculated the calculations show that 1 phase changes if present and activated contribute substantially to the subsidence of sedimentary basins 2 because the effect of phase change is delayed subsidence accelerates after a time on the order of 20 myr and 3 the duration of the subsidence is on the order of 100 to 150 myr during the late stages of subsidence the phase change is the dominating mechanism an application to the michigan basin is presented the calculated sediment accumulation history fits the record well when the effect of sea level changes is included in the model