ABSTRACT
In terms of geological history, an unconformity represents a period of time during which strata are not laid down. During this period, strata already formed may be uplifted and tilted by earth movements which also terminate sedimentation. The uplifted strata, coming under the effects of sub-aerial weathering and erosion, are ‘worn down’ to a greater or lesser extent before subsidence causes the renewal of sedimentation and the formation of further strata. As a result we find, in the field, one set of strata resting on the eroded surface of an older set of beds.
