Analogue and numerical forward modelling of sedimentary systems; from understanding to prediction

2 ...10 MODELING ALLUVIAL DEPOSITS...11 BRIDGE, J...11 LIMITS TO PREDICTABILITY ARISING FROM NON-LINEAR AND CHAOTIC BEHAVIOUR: RESULTS FROM A NUMERICAL STRATIGRAPHIC FORWARD MODEL OF CAR

Analogue and numerical forward

modelling of sedimentary

systems;

from understanding to prediction

9 – 11 October 2003

POROSITY PREDICTION THROUGH MICRO-SCALE SIMULATION OF GRAIN REARRANGEMENT

7

ALBERTS, L 7

2D AND 3D SUBSIDENCE ANALYSIS IN A COMPLEX FORELAND BASIN: THE VENETIAN BASIN (NE ITALY) 8

BARBIERI C 1 & GARCIA-CASTELLANOS D 2 8

QUANTITATIVE 3D MODELING OF SEDIMENTARY TRANSPORT MECHANISMS IN THE PERI-ALPINE FOREDEEP (UPPER MARINE MOLASSE, LOWER MIOCENE) 10

BIEG, U 1 , SUESS, M.P 1 , KUHLEMANN, A 1 & THOMAS, M 2 10

MODELING ALLUVIAL DEPOSITS 11

BRIDGE, J 11

LIMITS TO PREDICTABILITY ARISING FROM NON-LINEAR AND CHAOTIC BEHAVIOUR: RESULTS FROM A NUMERICAL STRATIGRAPHIC FORWARD MODEL OF CARBONATE SYSTEMS 13

BURGESS, P 1 & EMERY, D 2 13

FROM QUINCUNX TO DELTA: A STOCHASTIC CELLULAR AUTOMATA APPROACH TO THE CREATION OF FANS, VOLCANOES AND DELTAS 14

B URROUGH , P 14

MODELLING OF THE MIDDLE TO LATE PLEISTOCENE RHINE-MEUSE SYSTEM IN THE CENTRAL NETHERLANDS 15

BUSSCHERS, F.S & VAN BALEN, R.T 15

THREE-DIMENSIONAL MODELLING OF THRUST-CONTROLLED FORELAND BASIN STRATIGRAPHY 16

CLEVIS, Q 16

MODELLING THE STRATIGRAPHY AND PRESERVATION POTENTIAL OF MEANDERING STREAM DEPOSITS 17

CLEVIS, Q & TUCKER, G 17

NUMERICAL AND ANALOGUE MODELLING OF SEDIMENTARY BASIN FORMATION 18

CLOETINGH, S., GARCIA-CASTELLANOS, D., TER VOORDE, M & SOKOUTIS, D 18

FORWARD MODELING OF MEANDERING CHANNELIZED RESERVOIRS 19

COJAN, I., LOPEZ, S & RIVOIRARD, J 19

INCORPORATION OF NUMERICAL AND PHYSICAL FORWARD MODELLING INTO

UNCERTAINTY ANALYSIS METHODS 22

FEURER, J., & VAN DER ZWAN, C.J 22

ROLE OF FLUVIAL TRANSPORT DURING OROGENESIS: NEW NUMERICAL AND ANALOGUE MODELLING TECHNIQUES 23

DANIEL GARCÍA-CASTELLANOS, KATARINA PERSSON, DIMITRIOS SOKOUTIS, IVONE JIMENEZ-MUNT 23

A STRATEGY FOR AUTOMATED INVERSION OF PROCESS-BASED MODELS 24

G EEL , C.R.& W ELTJE , G.J 24

3D SIMULATION OF SEDIMENTARY FACIES: APPLICATION TO LANGHIAN REEF BUILDUPS IN VALLÈS-PENEDÈS BASIN (CATALUNYA) 25

GRATACOS, O 25

STRATIGRAPHIC FORWARD MODELLING OF DEEP MARINE SYSTEMS USING SEDSIM 26

GRIFFITHS, C 26

THE TECTONIC EVOLUTION OF THE NORTHERN NORTH SEA FROM THE MID-JURASSIC FORM 2D SUBSIDENCE ANALYSIS 27

HANNE, D 27

FINE-SCALE FORWARD MODELLING - EXAMPLE FROM A DEVONIAN REEF OF THE CANNING BASIN 28

MODELLING TURBIDITY CURRENTS BY CFD SIMULATIONS 29

HEIMSUND, S 1, 2 , HANSEN, E.W.M 3 , BAAS, J.H 4 & NEMEC, W 1 29

FORWARD MODELLING & PREDICTION OF AEOLIAN SYSTEMS USING FUZZY LOGIC, CONSTRAINED BY DATA FROM RECENT AND ANCIENT ANALOGUES 30

HERN, C 1 , NORDLUND, U 2 , ZWAN, C.J VAN DER 1 & LADIPO, K 3 30

USING SUB-REGIONAL SCALE FORWARD MODELS TO CONDITION RESERVOIR-SCALE STOCHASTIC SCENARIOS 31

HERN, C., LAMMERS, H., BURGESS, P & NIJMAN, M 31

INVESTIGATION OF GRAVITATIONAL MASS TRANSPORT PROCESSES - USING THE DISTINCT ELEMENT METHOD AS A MODERN TOOL IN SEDIMENT TRANSPORT MODELLING 32

H UHN , K & K OCK , I 32

MODELLING CYCLES OF FLUVIAL AGGRADATION AND DEGRADATION USING A PROCESS-BASED ALLUVIAL STRATIGRAPHY MODEL 33

KARSSENBERG, D 1 , BRIDGE, J.S 2 , STOUTHAMER, E 1 , KLEINHANS, M.G 1 & BERENDSEN, H.J.A 1 33

CHANNELISED TURBIDITY CURRENTS: NEW INSIGHTS INTO FLOW STRUCTURE AND SECONDARY CIRCULATION 34

KEEVIL, G 34

PREDICTING DISCHARGE AND SEDIMENT FLUX OF THE PO RIVER, ITALY SINCE THE LGM 35 KETTNER, A.J & SYVITSKI, J.P.M 35

MODELLING BEDDING AND PETROPHYSICAL CHARACTERISTICS OF TIDAL HETEROLITHIC RESERVOIRS USING A PROCESS-ORIENTED APPROACH 43

NUMERICAL MODELING OF THE SEDIMENTARY SYSTEMS OF LARGE-SCALE COASTAL

SYSTEM TRACTS 45

NIEDORODA, A.W., REED, C.W 1 , DAS, H 1 , DONOGHUE, J 2 , FERRAGHAZZI, S 2 , WANG, Z.B 3 & STIVE, M 4 45

3-D PHOTOREALISTIC MODELS OF GEOLOGIC OUTCROPS, A TOOL TO COLLECT QUANTITATIVE DATA; METHODOLOGY AND HISTORIES EXAMPLES IN UTAH AND WYOMING 46

OLARIU, C 46

UPSCALING THE TIME PARAMETER IN STRATIGRAPHIC SIMULATION MODELS: EFFICIENT USE OF HIGH-MAGNITUDE LOW-FREQUENCY EVENTS 47

O VEREEM , I 1 & S TORMS , J 2 47

ANALOGUE MODELLING AS A TOOL FOR INVESTIGATING CAUSALITY IN ALLUVIAL STRATIGRAPHY 49

GEORGE POSTMA 49

2D SUBSIDENCE MODELLING OF MIDDLE TRIASSIC CARBONATE PLATFORM DEVELOPMENT IN THE LOMBARDIAN ALPS (ITALY) 51

SEELING, M 51

THE COMMUNITY SURFACE-DYNAMICS MODELING SYSTEM: AN ENVIRONMENT FOR DEVELOPING, SHARING, AND USING SEDIMENT MODELS 52

SLINGERLAND, R 52

AVULSION, AUTOGENIC OR ALLOGENIC CONTROLLED? 54

STOUTHAMER, E & BERENDSEN, H.J.A 54

VARIATION IN DIP OF LATERAL ACCRETION SURFACES IN SUBRECENT FLUVIAL DEPOSITS, PANNONIAN BASIN, HUNGARY: A REFLECTION OF CLIMATIC FLUCTUATIONS OR JUST MEANDERING EXCURSIONS? 55

SZTANÓ, O 1 & MÉSZÁROS F 2 55

THE ROLE OF NUMERICAL SEDIMENTARY PROCESS MODELS IN HYDROCARBON EXPLORATION AND RESERVOIR CHARACTERIZATION 60

TETZLAFF, D 60

MODELS THAT TALK BACK 61

TIPPER, J.C 61

MODELLING THE IMPACTS OF CLIMATE CHANGE ON EROSION, SEDIMENT PRODUCTION, AND LANDSCAPE EVOLUTION 64

TUCKER, G 64

SCALED MODELS OF SYNTECTONIC SEDIMENTATION – REVIEW OF PRINCIPLES AND FIRST RESULTS 65

URAI, J.L & KUKLA, P.A 65

HIGH RESOLUTION 3D FORWARD STRATIGRAPHIC MODELLING OF CRETACEOUS

CARBONATE PLATFORM SYSTEMS 70

VAN DER ZWAN, C.J 1 , MASSE, J.-P 2 , BORGOMANO, J 1, 2 , LAMMERS, H 1 & FENERCI-MASSE, M 2 70

COMBINATION OF STRUCTURAL BALANCING, REVERSE BASIN AND FORWARD STRATIGRAPHIC MODELLING: SOUTHERN CANTABRIAN BASIN (NW-SPAIN) 72

VESOLOVSKY, Z 72

NON-UNIQUE SEQUENCE STRATIGRAPHIC ARCHITECTURES 73

WALTHAM, D., UDOFIA, M & NICHOLS, G 73

INSIGHTS INTO CARBONATE PLATFORM DROWNING MECHANISMS USING STRATIGRAPHIC FORWARD MODELING 74

WARRLICH, G & BURGESS, P.M 74

MODELLING SOURCE ROCK DISTRIBUTION AND QUALITY VARIATIONS: THE NEW OF-MOD 3D TECHNOLOGY 75

ZWEIGEL, J 75

Porosity prediction through micro-scale simulation of grain

rearrangement

Alberts, L.

Delft University of Technology, Department of Applied Earth Sciences, Mijnbouwstraat

120,

2628 RX DELFT, The Netherlands, l.j.h.albert@citg.tudelft.nl

Reservoir quality is commonly quantified in terms of the spatialdistribution of porosity and permeability, where the latter criticallydepends on the former Analytical methods of porosity prediction innatural sediments are not available, on account of the difficulties ofdescribing the geometrical arrangement of multi-sized particles ofirregular shape Available techniques to estimate porosity are empiricalequations that predict an exponential decrease of pore volume as afunction of effective stress, or focus on cementation processes Suchmethods do not incorporate uncertainty or variability of estimates,because they are tailored to data collected in a specific area A moregenerally applicable method of porosity prediction is needed to enhancethe usefulness of process-based stratigraphic simulators for reservoirmodelling

We have developed a numerical model that simulates the compaction ofparticle populations at a micro-scale The model comprises theinterparticulate mechanics that occur after deposition and during shallowburial, i.e prior to the phase in which chemical processes start todominate compaction Spatial continuity of the particle pack is simulatedthrough the use of periodic boundary conditions in X and Y, whereaselastic boundaries ('cushions') are implemented in the Z direction Theparticle pack thus represents an infinite layer of limited thickness, muchlike a single lamina The grain-size distribution of the pack is the keyparameter in the model The model is object based, which allows themechanics of each particle to be calculated, whereas the properties of theentire pack serve as global state variables during the rearrangement Withthis model we can simulate realistic trajectories of porosity decline fornatural particle-size distributions under several burial scenarios.Calibration of the model to physical experiments and sensitivity analyseswill be discussed, to provide a basis for the evaluation of uncertainty inmodel predictions The resulting particle pack can be used for simulations

of permeability, conductivity and wave-propagation studies

2D and 3D subsidence analysis in a complex foreland

basin: The Venetian Basin (NE Italy).

Barbieri C 1 & Garcia-Castellanos D 2

1 Department of Earth Sciences, University of Pavia, via Ferrata 1, 27100 Pavia, Italy,

chiara.barbieri@manhattan.unipv.it

2 Department of Tectonics, Vrije Universiteit, de Boelelaaan 1085, 1081 HV Amsterdam, The Netherlands.

The Venetian basin (NE Italy) is characterized by a complex geometry due

to the partial superposition of three foredeeps, different in both age andpolarity, associated to the development of the surrounding belts, namelythe Dinarides, the Eastern Southern Alps and the Northern Apennines,which underwent their main orogenic phases through Tertiary time.Therefore, it represents an interesting area to observe and betterunderstand the interplay between the evolution of mountain belts and theresponse of the adjacent foreland

The main goal of this work is to recognize and quantify the contribution ofsurface loads (i.e mountain belts, initial water depth, sedimentary infill)

and of possible deeper-sourced (hidden) loads, to the subsidence observed

in the basin This study constitutes the base for the analysis of thesedimentary infill

To this purpose, a former 2D flexural numerical modelling is applied alongtwo key transects trending NE-SW and N-S respectively, and a 3D flexuralanalysis is also performed to solve possible misfits occurring in the sectorswhich have been influenced by the combined effect of mountain belts Geological and geophysical data concerning the surrounding belts havebeen collected from literature In particular, data recently published in thecontext of the TRANSALP project, together with previously availableinformation on both subsurface and surface studies, provide an accuratedata set to study the effect of the Eastern Southern Alps on the Venetianbasin Moreover, interpretation and depth conversion of seismic lines andpaleobathymetric analyses have been performed in this work on someindustrial transects and wells respectively (courtesy of ENI), to integrateand improve the already existing data

Two dimensional forward modelling has been performed according to thenumerical method discussed in Zoetemeijer et al (1990) Gravimetriccurves have been also calculated to provide an independent constraint totest the reliability of the models, which show the present geometriesoccurring in the basin The model calculated on the basis of NE-SWtransect aims to test the flexural effect of the Dinaric belt whichunderwent the main orogenic phases during Paleocene-middle Eocene.The best fit has been obtained for a continuous plate condition and anEffective Elastic Thickness value varying along section Nevertheless, the

The second model, calculated along the N-S trending section, is focussed

on the flexure related to the main orogenic phases of the Eastern SouthernAlps (late Miocene-early Pliocene)

In this case a good fit has been obtained for a broken plate condition and aconstant Effective Elastic Thickness value of about 20 km The resultingcalculated flexure is strongly influenced by the initial water depth and nohidden load was needed to fit the observed flexure unlike a previouslyproposed model (Royden, 1993)

In spite of the good fit in front of the Eastern Southern Alps, a few metreshigh forebulge is expected to the South from the model but it is notobserved in the present Adriatic Sea In order to better understand themeaning of this mismatch, 3D modelling has been applied by means of the

software tao3D (Garcia-Castellanos, 2002)

To this purpose, flexure of the plate has been analysed in two steps byprogressively adding the loads due to the Eastern Southern Alps and theNorthern Apennines Results show that a forebulge form in the same area

as predicted by the 2D model if the Northern Apennine load is not takeninto account Subsequently this bulge is shifted to the South by theApennine load and it migrates eventually toward the Dalmatian region byincluding hidden loads, which are necessary to fit the flexure presentlyobserved in front of this belt

In conclusion, on the basis of the calculated models, a forebulge wouldexist at the end of Miocene in the area corresponding to the presentVenetian coastline, which subsequently migrated as a response to theApennine-related flexure This suggests also that the Apennines wouldhave affected the area of Venice since at least Pliocene – earlyQuaternary

Garcia-Castellanos D (2002) Interplay between lithospheric flexure and river

transport in foreland basins Basin Research, 14, 89-104.

Royden L (1993) The tectonic expression slab pull at continental convergent

boundaries Tectonics, 12, 2, 303-325.

Zoetemeijer, R., Desegaulx, P., Cloething, S., Roure, F and Moretti, I., 1990.

Lithospheric dynamics and tectonic-stratigraphic evolution of the Ebro Basin Journal of Geophysical Research, 95, B3, 2701-2711.

Quantitative 3D modeling of sedimentary transport mechanisms in the peri-Alpine foredeep (Upper Marine

Molasse, Lower Miocene)

Bieg, U 1 , Suess, M.P 1 , Kuhlemann, A 1 & Thomas, M 2

1 University of Tübingen, Department of Geoscience, Sigwartstr 10, 72076 Tübingen, Germany

Ulrich.bieg@uni-tuebingen.de

2 Technical University of Dresden, Institute for Planetary Geodesy

At the Aquitanian-Burdigalian boundary the Molasse basin was flooded by

a shallow tide- and wave- dominated seaway, linking the Rhône Basinthrough, the peri-Alpine foredeep with the Vienna Basin and thus with theeastern Paratethys Mass balancing of sediments derived from thedeveloping alpine orogen and the foredeep suggests a major export ofsediments towards the West during the Upper Marine Molasse (OMM,Burdigalian) Therefore it is of great interest which paleoceanographicprocesses were involved and potentially controlled the westward-directedtransport The widespread occurence of meso- to macrotidal facies succes-sions in the Molasse Basin adverts that tidal activity was a major forcedriving paleocurrents The aim of our study is therefore to provide anumerical model of sediment particle transport conditions within ashallow-water environment

We use QUODDY to model paleocurrents in this shallow foredeep.QUODDY is a Fortran implementation of a 3-D finite-element shelfcirculation model by the Dartmouth College (Lynch & Werner, 1991; Lynch

& Naimie, 1993; Lynch et al (1996) It is a free-surface, tide-resolvingmodel based on conventional 3-D shallow water equations Atmosphericforcing terms for wind stress and temperature flux can be implemented,

as wells as point source terms for rivers and adjacent alluvial plains

Further boundary conditions of the tides in the Paratethys were obtained

by calculating an initial tidal mode, based on a 1-degree reconstruction ofthe global bathymetry in the Miocene Based on paleogeographic dataderived from Martel, Allen & Singerland (1994) and new publishedpalaeogeographic maps of the alpine foredeep by Kempf & Kuhlemann(2002) we constructed an irregular triangular mesh with a varying gridresolution, to describe the paleobathymetry of the basin

First successful benchmarks were obtained by comparing with the model

of Martel et al (1994)

Kuhlemann, J., Kempf, O (2002): Post-Eocene evolution of the North Alpine Foreland Basin and its response to Alpine tectonics; Sedimentary Geology, Vol 152, pp 45 – 78.

Lynch, D.R., Werner, F.E (1991): Three-dimensional hydrodynamics on finite elements Part II: Non-linear time-stepping model; Int Numer Meth Fluids., 12, pp 507-533 Lynch, D.R and Naimie C.E (1993): The M tide and its residual on the outer banks of the

Martel, A.T., Allen, P.A., Slingerland, R (1994): Use of tidal-circulation modeling in the paleogeographical studies: An example from the Tertiary of the Alpine perimeter; Geology, Vol 22, pp 925-928.

Modeling alluvial deposits

Field studies of modern fluvial environments are difficult to

undertake during floods, over large areas, and for a long time, and it isdifficult to describe deposits below the water table Recently, some ofthese problems have been overcome by: using remote-sensing imagesand DEMs for studying changes in channel and floodplain geometry;measurement of water flow and sediment transport during floods usingnew types of equipment; description of deposits using GPR in combination

with coring, and OSL dating Laboratory flumes have been used to study

fluvial processes and deposits over a wide range of physical scales.However, scaling problems can limit the applicability of these studies tothe real world, and these problems increase as the scale of the physicalmodel decreases relative to the real-world prototype In particular, allsuperimposed scales of bedform and associated strata cannot beproduced in flumes, and rates of sedimentary processes are unrealistically

high Idealized models are ultimately based on studies of modern

sedimentary processes and deposits: therefore, short-term, small-scalemodels are well developed and most easy to test As the spatial andtemporal scale increase, useful models are more difficult to construct andtest Linkages between models of different scales are also lacking.Quantitative models for two scales of fluvial deposit are discussed here:deposits of alluvial valleys (or fans or deltas) with channel belts andfloodplains, and; deposits of channel belts

The most common approach to modeling deposits of alluvial valleys called alluvial architecture) is: determine geometry, proportion and

(so-location of distinct sedimentary bodies (objects) using well logs, cores, seismic or GPR; gain more information from presumed outcrop analogs; use stochastic (structure-imitating) models to simulate the geometry,

orientation and location of objects between wells; simulate rock propertieswithin objects using stochastic models Other types of stochastic modelsare not object-based, and make use of transition probabilities/Markovchains or indicator variograms Problems with the stochastic modelingapproach include: difficulty in defining input parameters for the model;over-reliance on outcrop analog data of dubious quality and usefulness;

forward (process-imitating) models are considered to be under-developed

and very difficult to fit to subsurface data However, forward based) models can give much better understanding of deposits and have

(process-predictive ability beyond the data region Furthermore, it is very likely thatthey can be fitted to subsurface data by trial-and-error with optimization(inversion)

The simple 3-D alluvial architecture model of Mackey and Bridge (1995)has been substantially developed by Karssenberg and others, and can now

be considered to be a quantitative 3-D fluvial sequence stratigraphymodel In addition to the processes simulated by Mackey-Bridge, this newmodel simulates geometric evolution of the channel network, upstreammigration of knickpoints, incised channels and terraces, and the effect ofaggradation-degradation cycles on avulsion and alluvial architecture

Channel-belt deposits have also been simulated using object-basedstochastic models: however, existing models are very unrealistic, mainlybecause of poor definition of object shapes and the methods forpositioning objects Deterministic quantitative models that consider flowand sedimentary processes in channel belts are not very well developed,and it is only possible to predict sedimentary details for individual channelbar deposits Further progress will be made as more information frommodern channel belts becomes available Recent work of relevance tomodeling suggests that there are general relationships between thegeometry of the different scales of bedforms (e.g., ripples, dunes, bars) inrivers and the geometry of their associated stratasets

Limits to predictability arising from non-linear and chaotic behaviour: results from a numerical stratigraphic forward model

of carbonate systems

Burgess, P 1 & Emery, D 2

1 Shell International Exploration and Production B.V., Postbus 60, 2280 AB Rijswijk, The Netherlands, Peter.Burgess@shell.com

2 Dept of Computing, University of Staffordshire

Most conceptual and indeed numerical models of sedimentary systemsassume simple linear behaviour, allowing straight forward predictionbased on a relatively simple relationship between cause and effect.However, another possibility for sedimentary systems is non-linearbehaviour leading to sensitive dependence and perhaps to chaoticbehaviour For even tiny differences in some starting condition, a systemexhibiting sensitive dependence may produce quite different strata, aphenomenon known as divergence Such systems are not easilypredictable; it is not possible to predict the in detail the behaviour of suchsystem over any time scale near or beyond the divergence timescale Toinvestigate this possiblity, a numerical stratigraphic forward model of acarbonate system with various non-linear components has been used togenerate autocyclic meter-scale shallowing-upward parasequences and toinvestigate the consequences of sensitive dependence on initial conditionsfor parasequence development Two model Cases with only a very smalldifference in initial starting topography have been run Stratal patternsfrom the two runs are similar in that both cases produce stackedparasequences with a similar range of thicknesses and showing generalshallowing upward trends However, thickness and facies distributionsdiffer significantly in detail as a consequence of divergence Attempts todetermine the Lyapunov exponent confirms that the model exhibitsdivergence but suggests that it is not truly chaotic These results suggestthat we may be well advised to look for sensitive dependence anddivergence in modern and ancient systems, and to take account ofpossibility of such behaviour in interpreting ancient strata; if realcarbonate systems show similar divergence to these model results,predictions from conceptual and numerical forward models should belimited to general patterns unaffected by sensitive dependence

From QUINCUNX to Delta: A stochastic cellular automata approach to the

creation of fans, volcanoes and deltas Burrough, P.

University of Utrecht, Faculty Geosciences, Utrecht Centre for Environment

& Landscape Dynamics, Heidelberglaan 2, Utrecht, The Netherlands,

p.burrough@geog.uu.nl

This presentation examines some useful stochastic models, includingFrancis Galton's Quincunx (or regression) board, for explaining thestatistical properties of "sedimentary" structures like fans, deltas andvolcanoes.  This will be illustrated with a critical examination of a set ofdynamic models created in a dynamic GIS environment The paper willillustrate how well-known geological structures might develop from purelystochastic processes driven by gravity.  It will show how minor variationsand modifications of initial conditions can affect the detailed outcome ofthe model but at the same time the generation of large numbers ofstochastic realisations demonstrates how easily variations on a generictheme can be arrived at, thereby enhancing our understanding ofgeological variation in the field

Modelling of the Middle to Late Pleistocene Rhine-Meuse

system in the central Netherlands

Busschers, F.S & Van Balen, R.T.

Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands,

freek.busscher@falw.vu.nl

The Saalian to Weichselian (OIS 6 to 2) Rhine-Meuse system in the centralNetherlands is a low-gradient fluvial system, located downstream of thehinge line of the southern part of the North Sea basin As a result, thedeposits of the Rhine-Meuse system (Kreftenheye Formation) consist ofstacked coarse-grained packages of sand and gravel Results ofmultidisciplinary analyses of new high resolution cores allow to construct adetailed model of the alluvial architecture of the Rhine-Meuse system Inaddition, over 80 OSL dates place the deposits in a well constrainedchronological framework The cores are located along three largetransects perpendicular to the main paleoflow direction The easternmosttransect is situated close to the hinge line, whereas the westernmost isclose to the present-day coastline A link to the offshore sediments is in

Our study shows that the Rhine-Meuse deposits consist of 6 to 7, 10-25kmwide stacked sediment bodies, formed during the last two glacial cycles.First results indicate that the formation of bounding surfaces is related toclimate (sediment availability  and discharge), glacio-eustacy and tectonicmovements (glacio-isostacy) These parameters also seem to control thegrainsize distributions of the separate sediment bodies Modelling thealluvial architecture will allows us to infer the relative importance of thesecontrolling factors This in turn will enhance predictions of 3D grainsizedistribution in this part of the Rhine-Meuse system, reducing the costs forthe exploration for sand and gravel in central Netherlands.Modelling will first be done on a deltaic scale (100 km), focussing on thelarger scale trends in architecture and grainsizes Subsequently, a smallerstudy area (5 km) will be selected for high-resolution modelling

Three-dimensional modelling of thrust-controlled foreland

 tonic parasequences and are formed only during phases of tectonicquiescence when eustatic falls are not longer compensated by thesubsidence component in the rise of relative sea level Suites ofamalgamating axial channels corresponding to multiple eustatic fallsdelineate the resulting Type-1 unconformities Coarse-grained, incisedchannel fills are found in the zone between the alluvial fan fringes and theconical body of the axial delta, as the axial streams tend to migratetowards this zone of maximum accommodation

Similar suites of amalgamating axial channel belts are created when theforeland basin is detached from its substratum by a hinterland-dippingsole thrust and transformed into a thrust-sheet top basin This is shown inthe second set of experiments Here, the competition between rates ofregional flexural subsidence, and local detachment-induced uplift controlsthe accommodation space evolution and the stratigraphic patterns in themarine-influenced thrust-sheet top basin Model experiments show thatdisplacement over low-angle faults (2~6 degr.) with moderate rates (~5.0m/kyr) results in a vertical uplift component sufficient to counteract thebackground flexural subsidence rate Consequently, the basin-wideaccommodation space is reduced, fluvio-deltaic systems carried by the

Modelling the stratigraphy and preservation potential of

meandering stream deposits

Clevis, Q & Tucker, G

Oxford University, Mansfield Road, OX1 3TB, Oxford, United Kingdom,

1)visualize the 3D spatial distribution of  these meandering streamdeposits and

2)quantify their preservation potential

as a function of the natural process of meandering, climatic change andhuman influence, using the CHILD landscape evolution model Thelandscape in the CHILD model is represented by an adaptable triangularmesh of nodes, especially designed for simulating the gradual shifting ofmeander bends.  A new layer track routine is currently added in order toimprove the resolution of the stratigraphic record accumulated by themodel

Numerical and analogue modelling of sedimentary basin

Case studies from different basinal settings, including the Pannonian –Carpathen system, the western Mediterranean and the Norwegiancontinental margin demonstrate the importance of lithosphere memory inbasin fill

Forward modeling of Meandering Channelized Reservoirs

Cojan, I., Lopez, S & Rivoirard, J.

Ecole des Mines de Paris, 35, rue Saint Honoré, Fontainebleau, France, cojan@ensmp.fr

Ecole des Mines de Paris has developed a strong experience in thecharacterization of heterogeneous reservoirs: Heresim pixel-basedtruncated and pluri-gaussian models, Boolean object-based models, andstudies of field analogs in various settings This expertise in geostatisticsand in sedimentology is used to combine both stochastic and process-based approaches in the modeling of fluvial meandering channels at theoil reservoir scale

The model is built from the spatial evolution of the channel in time, andthe deposition of the associated sedimentary bodies The differentelements have been implemented taking into account physical results andcase study reports The 3D evolution of the channel stems from equationsdeveloped in hydraulic studies and proved to generate realistic 2D shapes.Developments have been added to account for the longitudinal profile Astochastic algorithm linked with physical parameters allows to simulatechute cutoff, levee breaching and avulsions Where appropriate, the modelmakes it possible to generate the different deposits: point-bars, crevassesplays, overbank alluvium, mudplugs and lowland deposits

To be operational, the model is voluntarily controlled by a limited number

of key parameters These allow to build and to test different architectures,e.g making the sinuosity and connectivity of sand bodies varying withavulsions frequency, or reproducing external forcing (aggradation orincision) These key parameters can be inferred from seismic or well datathrough the use of statistics, such as Vertical Proportion Curves giving theproportions of facies along the vertical

Finally, the resulting model is simple but robust and computationally fast.Depending on a limited number of key parameters, yet capable torepresent various architectures, it can be used to produce one or multiplerealizations of a reservoir, to build detailed 3D blocks in order to testhypotheses on architecture, or to extract training images, virtual wells.Conditioning lithofacies or granulometry, either regionally or at well data,

is to be obtained by favouring migration or avulsion of the channel inpreferential areas

Paleozoic Basin Study: Structure, Stratigraphy and Quantitative Modelling in the Southern Cantabrian Mountains,

NW-Spain

Dietrich, B.

University of Heidelberg, Im Neuenheimer Feld 234, D-69120, Heidelberg, Germany,

birgit.dietrich@urz.uni-heidelberg.de

A genetic model for a multi-phase structurally deformed basin is created

by the authors The investigation area is located in the SouthernCantabrian Mountains of northwestern Spain which belongs to the externalpart of the Variscan fold-and-thrust belt Intense thin-skinned thrusting hastaken place during the Variscan Orogeny During the Alpine Orogeny, asecond deformation event occurred which locally overprinted the Variscandeformation by fault reactivation and development of out-of-sequence

Two transects positioned in the direction of thrusting are being studied.The stratigraphy to be modelled ranges from Cambrian to Carboniferous,focussing on the Carboniferous The Lower Paleozoic succession consistsmainly of shallow marine, siliciclastic sediments Devonian mixed clastic-carbonate sedimentation displays rapid lateral and vertical facies changesdue to the development of ramps, platforms and local basins

The Carboniferous strata start with condensed successions, followed bycarbonates deposited in a progressively shallowing marine environment infront of the rising Variscan Orogen Distal turbidites of the BarcalienteFormation are succeeded by the shallow carbonate ramp setting of theValdeteja Formation The upper part of the ramp deposits interfingers withrapidly lateral changing flysch deposits of the San Emiliano Formation.Allo- and biostratigraphy provide data to define time lines for quantitativemodelling

Due to thrusting, the complete thickness of the Carboniferous succession

is unknown Hence temperature data derived from vitrinite reflectionmeasurements aid in the interpretation

Backward modelling is used as a dynamic, deterministic analysis of thedevelopment of accommodation space Subsequent to the backwardmodelling, dynamic, stochastic forward modelling simulates sedimentationand transportation processes

Quantified Carbonate Platform Development: the Rosengarten Transect (Middle Triassic, Dolomites)

We identified two major stages of platform evolution – the first one withhigh subsidence rates and aggradational sedimentary characteristics andthe second one with low subsidence rates and strong progradationalcharacteristics The maximum of the total subsidence was reached afterthe first biozone of platform growth - 1100m/Ma in proximal and1000m/Ma in distal parts Then the subsidence slowed down to values ofabout 50m/Ma to 150m/Ma An explanation for the sudden stop insubsidence is the coeval development of a huge magmatic chamber in thearea of Monzoni/Predazzo neighbouring the Rosengarten Constantcarbonate production rates between 750m/Ma (platform slope) and850m/Ma (platform top) were determined by sequence stratigraphicforward modelling These rates proved to be sufficient to keep platformgrowth up with sealevel rise during times of high subsidence and toproduce fast progradation in the second stage of platform evolution

The mentioned modelling results are corroborated by the porosityevolution of the sediment package below the slope mimicing the N-S trend

of slope progradation Values of the regional vitrinite reflectance pattern inthe underlying Permian lie around 0.55%VRr The temperatures duringmaximum burial (presumably during Late Cretaceous times) mostprobably did not exceed 100°C However, samples from the Rosengartenarea neighbouring the Monzoni volcanic centre reveal values between 0.7and 0.8%VRr indicating that the thermal influence of the Monzoni eventwas restricted to its nearest vicinity The next step of our investigationswill be pinpointing the timing of subsidence with the help of fission trackanalyses in apatites

Incorporation of numerical and physical forward modelling

into uncertainty analysis methods

Feurer, J., & Van der Zwan, C.J.

SIEP-SEPTAR, EPT-AEP, P.O.Box 60, 2280 AB Rijswijk, NL Kees.VanderZwan@SHELL.com ,

Jeurg.Feurer@SHELL.com

Hydrocarbon occurrences rely on the concurrent presence of a validstructure, hydrocarbon charge, a reservoir and a seal The Oil Industryinvests millions in the predicting of these, in technology developments toimprove prediction, and many more millions in dry holes Shell has a longtradition in Monte Carlo simulation to manage subsurface uncertainty (e.g.uncertainty of porosity, closed rock volume, etc), and is increasinglybetting on the horse of forward modelling

Although lithological predictions integrate various well-establisheddisciples (e.g conventional and sequence stratigraphy, seismicstratigraphy, etc), the qualitative and quantitative forecasts remainvariably accurate and, at times, simply fall short on consistency Forward

modelling is an effective means of improving both: the consistency by

encouraging geoscientists to synthesize the (limited) data into one or

more subsurface models, and the accuracy by simulating actual physical

processes

To date forward-modelling tools have remained largely deterministic Thisbears the inevitable consequence of undersampling the uncertainty spaceand deriving sub-optimal statistics The power of today’s computers is nowsufficient to warrant the development of probabilistic forward-modellingtools capable of processing multiple alternative subsurface models

In this presentation an overview will be given of current probabilistic oilindustry methodologies and how these models can be linked to best-fitand scenario-based forward reservoir models

Role of fluvial transport during orogenesis: New numerical and

analogue modelling techniques

Daniel García-Castellanos, Katarina Persson, Dimitrios

Sokoutis, Ivone Jimenez-Munt

Free University Amsterdam

Erosion is a main process controlling the tectonic evolution of orogens,effecting on their internal structure Studies of the interplay betweenlarge-scale tectonics and surface transport usually assume 2D (crosssection) settings, whereas river networks drive surface transport typically

in the axial direction (parallel to the orogens) Do the spatial asymmetriesintroduced by fluvial transport influence on the tectonic deformationpattern during continental collision? The purpose of this work is toevaluate the 3D interaction between lithospheric deformation and fluvialtransport during continental collision For this purpose, we present results

of two new modeling techniques coupling a fluvial transport numericalmodel (stream power approach) with a (left) numerical model oflithospheric viscous deformation (thermally coupled thin-sheet approach)and a (right) analogue sandbox model of upper-crustal deformation

The Numerical Model fully couples a thermo-mechanical model oflithospheric viscous deformation and fluvial erosion/deposition The mutualfeeback’s effects between these processes are accounted for

The hybrid Numerical-Analogue Model fully couples the dynamics of ananalogue deformation model (sand-box) and the fluvial transportnumerical model Both components are linked via a scanner

The results show that surface erosion, transport and sedimentation have asignificant effect on the distribution of lithospheric and crustal deformationduring orogenesis The axial transport along the river network can inducelateral changes on the tectonic evolution of orogen-basin systems, such asdiachroneity These effects are probably less important than those induced

by inherited heterogeneities and lateral changes in the tectonic forcing

A strategy for automated inversion of process-based models

Geel, C.R.& Weltje, G.J.

Department of Applied Earth Sciences, Delft University of Technology, Mijnbouwstraat

120, 2628 RX Delft, The Netherlands, c.r.geel@ta.tudelft.nl

Application of process-based models in production geology has beenhampered by the difficulty of conditioning such models to well data.Several causes can be indicated, of which irreversibility is the mostimportant The occurrence of erosion surfaces prevents the application of

a direct, simple inversion Instead, a trial-and-error method or anautomated goal-seeking algorithm must be employed The fact that mostprocess-based models are CPU-intensive prohibits extensive trial-and-error

or automated goal-seeking approaches Another fundamental problem isthe choice of an appropriate objective function, i.e a criterion forquantifying the discrepancy between a certain realisation and the welldata The ideal objective function should be insensitive to local minima,while its value should be interpretable in probabilistic terms As these twoaspects are difficult to reconcile, we have focused on the first requirement

In this paper we present a method that circumvents many of theabove problems We use a very fast forward model, which can producehundreds of realisations in just a few minutes At the same time, themodel shows a sufficiently rich behaviour to mimic the first-orderdynamics of a shallow-marine environment The data to be matched arederived from permeability logs, as this quantity captures most features of

a given grain-size distribution in a single number Permeability logs arealso readily available for oil wells, while quantities like grain-sizedistribution or (litho) facies are usually not available We use a modifiedKarman-Cozeny equation to analytically determine permeability fromgrain-size distribution and porosity The latter is derived empirically frommeasurements on a series of lognormally distributed coastal sands.Characteristic permeability-log shapes are converted into characterstrings, from which the objective function value can be calculated Theobjective function itself is the Levenshtein distance widely used in spellchecking, speech recognition, DNA analysis, and plagiarism detection Arelatively straightforward genetic algorithm is used to minimise thisobjective function

The method was tested on a several (synthetic) cases withcomplicated, non-trivial geometries Up to seven parameters related tooscillations of sea level and sediment input could be inverted with a

3D simulation of sedimentary facies: application to Langhian reef buildups in Vallès-Penedès basin (Catalunya).

To date, various sedimentary modelling programs have been developed,most of them considering either clastic material or carbonate sediments,but very few models have attempted to consider interplaying, mixedcarbonate-clastic sedimentation Moreover, most programs are designed

in two dimensions in space, which is a major restriction as geologicprocesses work in three dimensions creating a great variety ofsedimentary facies types distributed in a complex 3D architecture ofsedimentary bodies

In this contribution, we present a 3D forward mathematical simulation(SIMSAFADIM) that simulates clastic transport and sedimentation as well

as processes of carbonate production, transport and sedimentation inthree dimensions

We test the predictive capability of the model by simulating a marinetransgression during Langhian time in the Vallés-Penedés basin(Catalunya, NE Spain) with a significant interplay between carbonate andterrigenous deposition

Stratigraphic Forward Modelling of deep marine systems

using Sedsim

Griffiths, C.

CSIRO, Australia, cedric.griffiths@csiro.au

Sedsim has evolved to be able to model many of the features ofsubmarine and lacustrine gravity-flow deposits including sandy basin-floorfans, channel-levee systems, ponded turbidites and debris flows. Examples are shown from modern and ancient systems, together withexplanations of the modelling assumptions

The tectonic evolution of the northern North Sea from the

Mid-Jurassic form 2D subsidence analysis

Fine-scale forward modelling - example from a Devonian

reef of the Canning Basin

Hasler, C.-A.¹ , Adams, E.W 2 , Wood, R.A 3 , Dickson, J.A.D.

1 University of Cambridge, Downing Street, CB2 3 EQ, Cambridge, United Kingdom,

chas02@esc.cam.ac.uk

2 MIT

3 Schlumberger Cambridge Research, Cambridge, United Kingdom

The spatial prediction of carbonate reef bodies within reservoirs - as well

as that of carbonate geometries in general - has proved difficult despitemany years of research by oil companies.  Forward modelling at a finescale may be a tool to better understand and predict the internaldiscontinuities within the reef bodies.  The modelling is based on the datacollected using a very accurate 3D differential GPS tools on severaloutcrops from the Devonian reef of the Canning Basin (Western Australia)

The modelling processes reconstitute the environmental conditions such

as the water-depth, the currents, the turbidity and the luminosity on thesea-floor in order to predict the lateral distribution of the majorprotagonists of the Devonian Reef Complex (stromatopororoids,stromatolites, tabulate corals, microbialites, coarse/fine sediments,micrite?)  The vertical evolution is constrained by the eustatic evolutionand by the ability of all the protagonists to grow and/or producesediments

Modelling turbidity currents by CFD simulations

Heimsund, S 1, 2 , Hansen, E.W.M 3 , Baas, J.H 4 & Nemec, W 1

1 Department of Earth Sciences, University of Bergen, 5007 Bergen, Norway

2 E-mail: snorre.heimsund@student.uib.no

3 Complex Flow Design AS, P.O Box 1273, 7462 Trondheim, Norway

4 Department of Earth Sciences, University of Leeds, Leeds LS2 9JT, U.K.

In this study, laboratory-scale turbidity currents have been simulated by anumerical approach known as computational fluid dynamics (CFD).Although relatively new in the field of sedimentological research, thismethod is widely applied in hydraulic engineering CFD refers to thesimplified numerical solution of the governing equations describing fluidflow, namely the continuity, momentum and energy equations These arethe mathematical formulations of the fundamental physical principles offluid dynamics: the mass and energy are conserved, and the Newtonsecond law is obeyed For a viscous flow, they are known as the Navier-Stokes equations The commercial CFD software package called FLOW-3Dhas been used in this study to perform numerical simulations of turbiditycurrents and to assess the validity of this deterministic method FLOW-3Dsubdivides the flow region into a grid of variable-sized rectangular cells,with finite-difference (or finite-volume) approximations used to compute(explicitly or implicitly) and monitor the spatial and temporal changes ofthe basic flow values for each cell The turbidity current is simulated using

a drift-flux technique, a two-phase model that describes the relative flow

of two miscible fluids with different densities For viscosity evaluation(turbulence closure) a renormalized group theory (RNG) model is used;employed are also auxiliary models for gravity, pressure, density, shearstress, particle-fluid interaction and the advection, erosion, settling anddeposition of sediment A 3-D model has been constructed to imitate thelaboratory ‘delta’ flume facility at the Utrecht University A number ofnumerical experiments have been performed, focusing on the mean flowproperties and flow structure of the whole current, including also theeffects of topography, erosion and deposition The relative sensitivity andimportance of the individual flow parameters have been assessed withrespect to variation in the initial conditions and seafloor configuration Acomparison of the numerical results with the Utrecht laboratory datashows their good correspondence, which indicates that the CFD modelsgive realistic results and may be quite suitable for the simulation ofturbidity currents

Forward Modelling & Prediction of Aeolian Systems Using Fuzzy Logic, Constrained by Data from Recent and Ancient

Analogues

Hern, C 1, Nordlund, U 2 , Zwan, C.J van der 1 & Ladipo, K 3

1 Shell SEPTAR, P.O.Box 60, 2280AB Rijswijk, The Netherlands, caroline.hern@shell.com

2 Herrboda, se-74020 Vänge, Sweden

3 PDC, Port Harcourt Nigeria

Aeolian reservoirs yield some of Shell‘s largest gas fields, such as NAM’sGroningen field Although, aeolian reservoirs have been studied for manyyears,

there is still room for improvement in the prediction of such reservoirs.With this

intention, a project was initiated to evaluate the factors influencing aeoliansystems, and deveolp a forward model using ‘fuzzy logic’

The key aims were to:

 predict the type, amount and distribution of major facies types inaeolian systems and,

 to compare resultant models with the regional-scale architecture Fuzzy rules and sets, which define the behaviour of aeolian systems, wereconstructed and used to modify the pre-existing fuzzy modelling software.The modelling procedure was validated by using input data appropriate tothe Rotliegend climate and comparing the resulting models, in terms ofthicknesses and spatial distribution of facies types, to well data from theUpper Rotliegend interval of the Lauwerzee Trough area, NE Netherlands

Using sub-regional scale forward models to condition

reservoir-scale stochastic scenarios

Hern, C., Lammers, H., Burgess, P & Nijman, M.

Shell SEPTAR, P.O.Box 60, 2280AB Rijswijk, The Netherlands, caroline.hern@shell.com

Reservoir scale 3D static models are constructed based on available welland seismic data, yet in many cases well data is sparse and seismicresolution is poor This lack of well or seismic control in the area of interestmay result in an unconstrained and unrealistic population of the 3Dvolume In order to honour more truthfully the geology, one approach may

be to condition the reservoir scale model to a regional scale numericalforward model

Advances in predictive numerical forward modelling have enabledconstruction of models constrained by available well data that reproduceand predict realistic geological architectures at a number of scales Weshow how a sub-regional scale (37km long) forward model of the GrassyMember of the Blackhawk Formation (Utah), constructed in Dionisos, wasused to condition a reservoir scale hybrid stochastic model The forwardmodel was clipped to extract a volume representative of a small reservoir(3 x 2km) The gross distribution of facies associations indicated in theforward model was used as a background in the stochastic model, intowhich shale objects were distributed

We compare the resultant hybrid model with detailed 3D models built andconditioned to synthetic wells derived from the outcrop panels

The methodology illustrates how the forward predictive capability ofDionisos models at a sub regional scale, can be harnessed and utilised inconjunction with reservoir modelling packages to fully describe faciesscale variation at the reservoir scale

Investigation of gravitational mass transport processes using the Distinct Element Method as a modern tool in sediment

-transport modelling

Huhn, K & Kock, I.

Research Center Ocean Margins, University Bremen, Am Fallturm 1, D-28334, Bremen, Germany, khuhn@uni-bremen.de

High-production regions, i.e the NW African continental slope offshoreMauritanian, are characterized by high sedimentation rates at the upperslope These materials are episodically transported down-slope in form ofslides of intact layered packages or by mixed and disordered debris flowsand turbidites The main purpose of our studies is to investigate theinfluence of different key parameters for (a) slope failure as well as (b)deformation and kinematic behaviour of gravitational mass flowprocesses

For our studies we use a numerical particle-based method - the DistinctElement Method (DEM) This technique enables a wide range of materialparameters and model configurations DEM simulations have been proved

as an efficient tool to quantify the influence of material parameters, i.e.basal as well as internal friction, and geometrical settings forgeodynamical processes like gravitational mass flows This methodenables detailed information about mechanics and kinematics of down-slope processes, mass transfer patterns, as well as internal andmorphological structures

Nevertheless, we have to investigate the influence of model configurationsand assumptions in the face of transferability of model results into anatural system Thus, we develop a 2d DEM model which is built up ofspherical, elastic frictional particles These spheres interact according tononlinear-elastic Hertzian contact laws The total number of particles ineach experiment is constant to simulate identical sedimentation rates.First, we investigate the influence of deposition of sediments Therefore, inexperiment (a) all spheres settle down under gravity in a triangularshaped box on top of the upper slope Removing the box boundariesreleases a gravitational mass flow In experiment (b), all particles aresettled under gravity on top of a shelf surface and they are transportedprogressively by a bulldozer to the upper slope In both experiments, wechange iteratively the basal friction on top of the slope as well as internalfriction of sediments A decrease of basal friction as well as of internalfriction of sediments causes always an increase of run out length of theflow while decreasing the thickness In addition, an increase of internal

Modelling cycles of fluvial aggradation and degradation using a process-based alluvial stratigraphy model

Karssenberg, D 1 , Bridge, J.S 2 , Stouthamer, E 1 , Kleinhans, M.G 1 & Berendsen, H.J.A 1

1 The Netherlands Centre for Geo-ecological Research (ICG), Faculty of Geographical Sciences, Utrecht University, PO Box 80115, 3508 TC Utrecht, the Netherlands,

10 km2, defined by grid cells with a constant size, and a vertical resolution

of less than 10-2 m Sediment is transported by diffusional transportthrough a network of channels with a sediment flux boundary condition atthe upstream point of entry and a base level boundary condition at thedownstream edge of the model Both boundary conditions can be varied intime Each channel has a channel belt with a width that increases in time

at an exponentially decreasing rate The network of channels evolves as aresult of channel bifurcation and channel abandonment The timing andlocation of channel bifurcation is controlled stochastically as a function ofthe cross-valley slope of the floodplain adjacent to the channel beltrelative the down valley slope Channel abandonment, resulting in abifurcation developing into an avulsion, occurs when the discharge of one

of the distributaries falls below a threshold value

Floodplain aggradation occurs adjacent to actively aggradingchannel-belts on floodplain surfaces that do not exceed the elevation ofthe active channel belt Floodplain aggradation rate decreasesexponentially with distance from the active channel belt Channel-beltdegradation results in floodplain incision and transport of eroded sedimentfrom valley walls towards the incising channel belts The erosion of valleywalls is calculated as a function of stream power for each location on thevalley wall Compaction of channel-belt and floodplain deposits is modelled

as a function of depth of burial Tectonic movement can also be simulated

by faulting and/or tilting of the floodplain in any direction

The model is programmed in a standard spatio-temporal modellinglanguage that uses built-in functions and that allows easy addition of newmodel components The model can be run in Monte Carlo simulationmode, such that many model runs are made to evaluate the effects ofuncertainty in model input parameters The model is still being developedand tested against real-world data However, examples are given of the

Channelised turbidity currents: new insights into flow

structure and secondary circulation

Keevil, G.

School of Earth Sciences, Leeds University, LS2 9JT, Leeds, United Kingdom,

g.keevil@earth.leeds.ac.uk

Sinuous submarine channels are major morphological features which act

as conduits for the transport of clastic sediment into the deep ocean. Such channels have long been considered to be analogous to meanderingfluvial channels.  These comparisons are commonly driven by similaritiesbetween the planform geometries of submarine and fluvial channels

Recent laboratory studies have revealed much about the velocity anddensity structure of unconfined turbidity currents.  The velocity structureand pattern of secondary circulation (helical vortices with the long axisaligned parallel to flow) within meandering fluvial channels is also wellunderstood.  However, prior to this work, very little was known about thevelocity and turbulence structure of channelised turbidity currents

Results from a series of new experiments will be presented where densesaline flows were pumped into submerged meandering channel sections. Ultrasonic velocity probes (UVP) provided high-resolution two dimensionalflow fields.  This has for the first time allowed the quantification of thevelocity profile of a channelised turbidity current within a sinuouschannel.  Additionally these experiments have enabled the visualisationand quantification of secondary cells within these channels.  The resultsclearly demonstrate a strong secondary flow cell which is strongest at thebend apex.  The basal component of the flow cell moves from the inside tothe outside of the bend, the reverse of what is expected within a fluvialchannel.  Such a finding has great significance when assessing the validity

of the comparison between meandering fluvial channels, where thesecondary flow cells influence the migration and evolution of bends, andsinuous submarine channels.  It implies that different processes controlthe morphological evolution of sinuous submarine channels

Predicting discharge and sediment flux of the Po River,

Italy since the LGM

Kettner, A.J & Syvitski, J.P.M.

Environmental Computation and Imaging Group, Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder CO, 80309-0450, United States,

Kettner@colorado.edu

INTRODUCTION

The EuroSTRATAFORM project aims at evaluating the influences ofphysical characteristics of sediment sources and their temporal variabilitydue to climatic evolution and human impacts on continental-marginsediment flux In the framework of the project a number of rivers werechosen to simulate; among others, the Po

A numerical climate-driven hydrological model, HydroTrend, is applied

to the heavily anthropogenic influenced Po basin (drainage area 77,000

km2) in Northern Italy to predict sediment fluxes and water discharge tothe Adriatic Sea since the Last Glacial Maximum (LGM)

MODEL CONCEPTS OF HYDROTREND

To simulate discharge and sediment discharge fluxes, HydroTrendincorporates drainage basin properties (river networks, hypsometry, relief,reservoirs) based on high-resolution digital elevation models (for exampleHYDRO1k DEM), along with other biophysical parameters (basin-widetemperature, precipitation, evapo-transpiration, canopy, soil depth,hydraulic conductivity, glacier characteristics) A stochastic model(Morehead et al., 2003) is used to calculate the daily suspended sedimentload fluxes:

(1)

Wherein Qs is the daily suspended sediment discharge (kg/s), Q the daily

discharge (m3/s), the long-term average of Qs, the long-term average

of Q,  a log-normal random variable and c a normal random variable The long-term average of Qs is defined as:

(2)

Wherein A is the drainage basin area (km2), R the maximum relief (m),

the basin-average temperature (C), 3, 4, 5 and k dimensionless

coefficients which depend on climatic zone based on the geographicallocation of the drainage basins (Syvitski et al., in press b) studying the

or k The Long-term average suspended sediment will only be affected by changes in A, R and

The daily bedload Q b (kg/s) is simulated using a modified Bagnold(1966) equation:

Where s is sand density (kg/m3),  is fluid density (kg/m3), Q is the daily

discharge (m3/s), s is the slope of the riverbed (), e b is the bedloadefficiency,  is a dimensionless bedload rating term, f is the limiting angle

of repose of sediment grains lying on the river bed (), u is stream velocity (m/s), and u cr is the critical velocity (m/s) needed to initiate bedloadtransport

The model with documentation, example files and references is

CALIBRATION TEST, PRESENT DATA VERSUS MODELED

Present-day climate statistics including monthly mean temperature andprecipitation and their standard deviations of the Po drainage basin areretrieved from daily data records (1977 - 1991) of 20 climate stationsweighted in terms of influence by elevation The yearly mean temperature,precipitation and their standard deviations also weighted in terms ofinfluence by elevation are obtained from monthly data records (1760 –1995) of 13 climate stations from the Global Historical ClimatologyNetwork of National Oceanic and Atmospheric Administration, (NOAA)(Vose et al., 1997)

HydroTrend verifies as an appropriate simulation model for the gaugingstation closest to the river mouth before being split into distributarychannels At this delta apex there is a high correlation between modeleddischarges and time series of daily discharge data (1990-2001) andmonthly discharge (1918-present) HydroTrend also generates similardischarge variability as compared to the 12-year daily measureddischarges (fig 1) Modeled data correlates significantly with the observeddata (r2 of 0.72), as calculated from 100m3/s intervals

Figure 2 indicates that the monthly mean discharges are underpredictedduring the winter months (November till March) and overpredicted duringthe summer (April till September) This deviation relates to the well known

20 00 -3 00 0

30 00 -4 00 0

40 00 -5 00 0

50 00 -6 00 0

60 00 -7 00 0

70 00 -8 00 0

80 00

- 90 00

Fig 1 Discharge distribution of12yr daily mean measured versus modeled

ch

April May June July

August

Dece

mber

Fig 2 Monthly mean discharge distribution based on 100yr monthly

measured versus modeled data The dashed lines indicate mean discharge values plus or minus their standard deviation The arrows show the huge impact the reservoirs have on the monthly mean

The Po’s discharge is strongly affected by its 5 large reservoirs,sediment fluxes will likely be influenced even more HydroTrend to someextent can be adjusted to incorporate reservoir effects on sedimentation

The model simulates trapping efficiency TE depending on the reservoir

volume either by the Brown equation, for reservoirs smaller or equal than0.5 km3, or the modified Brune equation by Vörösmarty (1997), forreservoirs larger than 0.5km3 (formula 4 and 5)

suspended sediment load for the entire Po drainage basin

At the delta apex, HydroTrend predicts an average discharge of 1,542

m3 s-1 and peak discharges comparable to the measured floods of 1951and October 2000 Based on the formulas 1, 2 and 3, average suspendedsediment load of 16 x 106 t yr-1 with peak years of 39 x 106 t yr-1 arepredicted Bedload contributes only ~2.5% of the total sediment output ofthe Po river system (table 1) There is a good correlation between bedloadtransport and high suspended sediment concentrations, figure 4

100yr simulation.

Measured

at apex (Pontela- goscuro)

10,28110,1109,779Average suspended sediment load