Positive fault inversion triggering 'intrusive diapirism': An analogue modelling perspective

Understanding the formation and the development of salt structures is very important especially because they are of significant economical interest for hydrocarbon trapping and for long-term storage of radioactive waste and energy reserves. Generally, the activity of normal faults developed in extensional regimes is considered the most efficient mechanism for salt diapirs. The results of analogue models reported in this paper suggest a new triggering mechanism for the rise of salt structures during basin inversion. This mechanism relates the localization of ductile diapirs to early normal faults only after their inversion during later shortening. In this case, diapiric growth is related to the strong dip-slip reactivation component along the fault extruding the silicone-simulating salt upward. Some natural cases, in which the timing and the mechanism of diapiric growth is not clear, can be re-interpreted in the light of these analogue model results. © 2005 Blackwell Publishing Ltd.