Clay smear processes in mechanically layered sequences -

Results of water-saturated model experiments

 

Joyce Schmatz and Janos L. Urai

 

Project funded by: ExxonMobil Upstream Research Company, supervised by P. Vrolijk

 

 

 

We constructed an “underwater”-sandbox to deform layered sand-clay packages of 20x40x20 cm above a 70° dipping rigid basement fault.

 

 

The experiments are run completely water-saturated to allow the deformation of wet clay and cohesionless sand.

 

 

Movie showing sand-only experiment (experiment sand-only) with a 140 mm high sand package and top plates.

 

 

Movie showing sandbox experiment (1t30ohne) with a 30 mm thick firm clay layer in the centre of the model and a free top surface (from bottom to top: 50 mm sand, 30 mm clay, 60 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 1t30ohne with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing sandbox experiment (1t30hor) with a 30 mm thick firm clay layer in the centre of the model and top plates (from bottom to top: 50 mm sand, 30 mm clay, 60 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 1t30hor with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing experiment (experiment 2s40sand3rd) with two 3 mm thick soft clay layers and top plates (from bottom to top: 40 mm sand, 3 mm clay, 40 mm sand, 3 mm clay, 54 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 2s40sand3rd with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing experiment (025perc2cement) with two 3 mm thick cemented clay layers and top plates (from bottom to top: 50 mm sand, 3 mm clay, 50 mm sand, 3 mm clay, 34 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 025perc2cement with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing experiment (03cement3) with one 3 mm thick cemented clay layer and top plates (from bottom to top: 60 mm sand, 3 mm clay, 77 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 03cement3 with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing sandbox experiment (experiment 15perc2cement) with two cemented (1.5 wt.%) clay layers and top plates. Setup from bottom to top is: 50 mm sand, 3 mm clay, 50 mm sand, 3 mm clay and 34 mm sand.

 

 

Movie showing the corresponding PIV overlay to experiment 15perc2cement with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing experiment clay01 with two soft clay layers separated by a thin sand layer and free top surface. Setup from bottom to top is: 20 mm sand, 50 mm clay, 5 mm sand, 50 mm clay and 40 mm sand.

 

 

Movie showing experiment (experiment 1s30hor) with one 30 mm thick soft clay layer and top plates (from bottom to top: 55 mm sand, 30 mm clay, 55 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment 1s30hor with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Movie showing experiment (multilayer01) with four 8 mm thick soft clay layers and top plates (from bottom to top: 30 mm sand, 8 mm clay, 12 mm sand, 8 mm clay, 12 mm sand, 8 mm clay, 12 mm sand, 8 mm clay, 30 mm sand).

 

 

Movie showing experiment (multilayer02) with four soft clay layers and top plates (from bottom to top: 35 mm sand, 20 mm clay, 10 mm sand, 3 mm clay, 10 mm sand, 20 mm clay, 10 mm sand, 2 mm clay, 40 mm sand).

 

 

Movie showing the corresponding PIV overlay to experiment multilayer02 with the velocity vector field in the foreground and a contour plot of the z-component of the incremental rotation field in the background.

 

 

Literature

 

Schmatz, J. and Urai, J.L. submitted. Clay smear in mechanically layered sequences – the effect of multilayers and clay cementation in water-saturated model experiments. Journal of Structural Geology, Special Issue: Fault Zones.

 

Schmatz, J., Holland, M., Giese, S., van der Zee, W., Urai, J.L. in press. Clay smear processes in mechanically layered sequences – results of water-saturated model experiments with free surface. Journal of the Geological Society of India, Special Issue 03, R1.

 

Adam, J.; Urai, J. L.; Wieneke, B.; Oncken, O.; Pfeiffer, K.; Kukowski, N.; Lohrmann, J.; Hoth, S.; van der Zee, W.; Schmatz, J. 2005. Shear localisation and strain distribution during tectonic faulting - new insights from granular-flow experiments and high-resolution optical image correlation techniques, Journal of Structural Geology, 27, 2, 283-301.