Monday, 16 January 2012

Mapwork from models 6: plain with faults in the direction of dip

In this latest ELI mapwork from models activity, pupils are shown a photograph of a plain and then are asked to cut out a 3D paper model of a flat plain-like area. They should use the cut-out to make the first version, then either cut out another
model, or turn the first model inside out, and trace the geology to make the second version.
Plain with faulted rocks, version 1.
With the experience from previous Earthlearningidea models, pupils should realise that when dips are known (as for the fault) they can be drawn using a protractor, and that dipping beds appear horizontal for cross sections drawn at right angles to the dip direction (strike-sections). This makes completing the model fairly
straightforward. Faults like this, which are parallel to the dip of the beds, are called dip faults.
Plain with faulted rocks, version 2.
Completion of this model is even more straightforward, since the fault is vertical and all other lines are drawn in the same places.
However, completion of the second model shows an important geological fact, that the same outcrop pattern can be produced by a normal fault as by a tear fault.
This is one of a series of Mapwork from models exercises on our website. The others can be found in the Investigating the Earth category

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