Physical modelling of North Sea salt diapirism

Abstract

Scaled analogue models provide a powerful tool for investigating progressive deformation. By varying experimental parameters it is possible to produce a wide variety of diapir morphologies and overburden responses.This paper describes the results of one of a series of experiments which investigates the geometry of overburden sediments around diapirs. The roles of basement faulting and differential sediment loading in the growth of diapirs are assessed. The template for this experiment is provided by analysis of a regional seismic line across the Central Graben of the North Sea.The model produced two diapir types which formed in different ways. Type 1 diapirs are initiated by a large fault smearing the salt along the fault plane which creates a path for later upward migration of salt to produce small diapiric walls. Type 2 diapirs can be triggered by either tectonic or sedimentary differential loading. They are predicted to be longer lived and more voluminous than Type 1 diapirs and will tend to form isolated circular structures.