Can Layers Pinch Out in Stratigraphy Plots?

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EQuIS 7  >>  EnviroInsite > Frequently Asked Questions > Stratigraphic Modeling >

Can Layers Pinch Out in Stratigraphy Plots?

Representing pinched-out layers starts with the loading of the Stratigraphy table in the EnviroInsite database. If a unit is absent at a particular borehole, you have the option of entering a record with a zero thickness (the same top and bottom depth) for the unit or simply leaving the record out. If you leave the record out, make sure that the overlying and underlying units meet vertically at these locations.  

 

Once you've created your cross-section and plotted the stratigraphy, you may find that the program's interpretation of the lateral extent over which that unit is absent differs from your judgment. You may be able to modify this by altering the interpolation parameters to change the persistence of impacts from measured thicknesses with distance or you can modify the units by hand. To modify "by-hand", simply click in the unit with contact elevations you want to change. This will cause the grip boxes to appear. Click in the grip box you want to move (upward or downward) and then click again at its new elevation. Edit the stratigraphy plot and make sure that the Detach from Data option is selected so that your interpretations are not overruled by the automated data calculations the next time the plot is redrawn.