3d geological modelling of the state of vaud: first steps...

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3D Geological modelling of theState of Vaud:

first steps with the map of Nyon

Thomas JOLIMET, Laurent TACHER, Aurèle PARRIAUX, Marc WEIDMANN, David GIORGISThomas JOLIMET, Laurent TACHER, Aurèle PARRIAUX, Marc WEIDMANN, David GIORGIS

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Why did we made the choice of modelling Why did we made the choice of modelling NyonNyon’’s s territory?territory?

High complexity of Quaternarydeposits on the Plateau andelaborated structure in Jura

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Model made with geotypes :

1.Geotypes have been defined for their hydrogelogicaland/or geotechnical features

2.Already in use by State of Vaud’s administration

Challenge:

How to get through from limited data (geological maps,logs,…) to continuous data (3D model) ?

Make the information denser

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Model Building : make the information denser in…I. Quaternary deposits :I. Quaternary deposits :

I.1 with geological cross-sectionsI.2 lenses modelling

II. Tertiary and Mesozoic depositsII. Tertiary and Mesozoic depositsII.1 A new picture of the Molasses’ top on the PlateauII.2 Jura’s folds modelling with structural maps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D Model

III.1 Stratigraphic column

III.2 Results

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I. Quaternary deposits :I. Quaternary deposits :

I.1 with geologicalcross-sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

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•15 lenses undergroundwithin Quaternarydeposits

•7 geotypes on surface

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture ofthe Molasses’top on thePlateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

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•Large and deep subglacialvalley (from Gingins toBursinel) featuring, at least,4 glaciation periods

•Glacial erosion issometimes lead by majorstrike-slip faults

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s foldsmodellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

« Official » cross-section from Nyon’s geological map

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Height of Reef ComplexHeight of Reef Complex’’s tops top((KimmeridgianKimmeridgian))

PurbeckianPurbeckian’’ss Top height Top heightbetween two major reversebetween two major reverse

faultsfaults

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault dataextrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

1. De Kemp, E. A. (1998), Three-dimensional projection of curvilinear geologicalfeatures through direction cosine interpolation of structural field observations,Computers and Geosciences, 24(3), 269-284.

2. Groshong, R. H. (2006), Chap12 - Direction Cosines and Vector Geometry, in 3-DStructural Geology: A Practical Guide to Quantitative Surface and Subsurface MapInterpretation, edited, p. 373, Springer

AWK script (De Kemp,1998) on Linux leading toextrapolations using main azimuth and dip

(cossines)

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D Model

III.1 Stratigraphiccolumn

III.2 ResultsStratigraphicStratigraphic column used to established a model of the Jura area covering column used to established a model of the Jura area covering

Mesozoic era (down to Mesozoic era (down to OxfordianOxfordian age) age)

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All surface are obtained by isopach calculations(constant bed thickness – concentric folds) from

reference surface

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I. Quaternary deposits :I. Quaternary deposits :I.1 with geological cross-

sections

I.2 lenses modelling

II. Tertiary & MesozoicII. Tertiary & Mesozoicdepositsdeposits

II.1 A new picture of theMolasses’ top onthe Plateau

II.2 Jura’s folds modellingwith structuralmaps

II.3 Fault data extrapolation

III. 3D ModelIII. 3D ModelIII.1 Stratigraphic column

III.2 Results

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•43 reference surfaces with a 50m mesh

•Including main Quaternary formations (fluvio-glacial, glacio-lacustrine, ground morraines or lateral morraines, etc…) andMesozoic formations (down to Oxfordian age)

•Including major strike-slip and reverse faults

•Developed for geothermal assessment purpose but can beused for other applications

••Overview of the present knowledge that can be deeplyOverview of the present knowledge that can be deeplymodified with any new geological information about this regionmodified with any new geological information about this region

Main features and ConclusionsMain features and Conclusions

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Thanks a lotThanks a lot