Tectonic modelling laboratory (TecLab)

In our tectonic modelling laboratory (TecLab) we use "scaled analogue models" to better understand large scale tectonic deformation processes, such as the breakup of the Earth's crust or the formation of mountain ranges.

Scaled analogue model of Afar region in Ethiopia. Erosion of the surface is simulated by removing material using a vacuumcleaner.

An analogue model is often prepared inside a plexiglass box with dimensions typically 50x50x20cm (Fig. 2, top-left). A model consists of stack of several layers of different types of sand and/or silicone putty, each layer a few centimeters thick, floating on top of a heavy fluid layer. The sand and silicone layers represent the different multi-km thick rock layers that form the Earth's mechanically strong upper parth (the lithosphere), while the fluid represents the hot and viscous upper mantle layer called the asthenosphere.

(top left) example of a scaled analogue model; (bottom left) vertical section through a model subjected to horizontal shortening; (right panel) top view image of a model, showing the development of elongated areas of uplift.

Tectonic deformation occurs when the lithosphere is subjected to mechanical and/or thermal loading, either horizontally ("extension" or "compression") or vertically ("erosion", "sediment loading", "hot mantle plume"). Such loads are simulated in the TecLab by, for instance, very slowly pushing or pulling one of the walls of the box. In response the layers of the model will start to deform, with the mode and intensity of deformation depending mainly on the (changes in) material properties of the layers and on the rate and magnitude of the applied external loading. When the layers in the analogue model are squeezed together, they will start to break and partly glide on top of each other along faults. This deformation is revealed when we cut the analogue model along vertical sections, as shown in the bottom left panel of Figure 2.

Due to the tectonic deformation inside a model, also the top surface of the model starts to deform: some parts will be uplifted, other parts will subside. This is illustrated nicely in Figure 2 (right panel), which is a digital picture of the top surface that shows the development of elongated uplifted areas (in red), which is interpreted geologically as the formation of a new mountain range (e.g. the Alps).

During an experiment we repeatedly make pictures and laser scans of the top surface of ananalogue model, so that we can track the surface development not only in space but also in time.

Contact email for TecLab specific information: teclab.geo@uu.nl