UNCONFORMITIES

www.earth-science-activities.co.uk

Unconformities
Making unconformities
A P 15 min
Students lay several different coloured sheets (2cm by 10cm) of plasticine on top of
each other, then fold them, then cut off the top using a knife, after which they lay two
more layers on top. One can also add faults and dykes
Angle of dip
A I 5 min F
Students are given diagrams of unconformities where the strata above the unconformity
are dipping. Students work out the angle of dip of the lower strata at the time the
unconformity formed. Use only the simplest case where the strikes of both sets of
strata are parallel.
Minimum thickness eroded
A I 5 min
Students are given a cross section of an unconformity and must work out the minimum
thickness that has been eroded which is the thickness between the youngest and oldest
bed eroded.

Earth Science Activities and Demonstrations