FOLD-GENERATED IMBRICATES - EXAMPLES FROM THE CALEDONIDES OF SOUTHERNNORWAY

The Cambro-Silurian sequence of the Oslo Region contains fold trains a nd closely spaced imbricate thrust faults. The imbricates could be int erpreted as having ramped off the sole detachment and generated fault- propagation folds. Several imbricate thrusts, however, appear to die o ut both downwards and upwards into folds. This suggests that the thrus ts were generated within the Cambro-Silurian sequence and propagated d own to the sole thrust rather than propagating upwards from the sole t hrust. The mechanical stratigraphy is apparently responsible for this style where, during folding, relatively brittle limestone members faul ted in the highly strained fold forelimbs prior to through-going fault ing developing in the shales. Understanding the origin of such imbrica tes is important when choosing a method of section restoration.