The Salt Dome problem: A multilayered approach

Abstract

The dynamical evolution of buoyancy‐driven geological systems is mainly influenced by two physical parameters: density and equivalent viscosity. Salt structures are an appropriate geological representation of these systems. Important variations of these parameters are directly related to changes in mass, and thus the internal structures themselves and their changes in time become significant parameters. In order to decipher these structures in nature by means of experiments it is therefore necessary to extend model calculations on intrusion processes to multilayer systems. A two‐dimensional finite element program has been developed to simulate the rise of individual diapirs through multi‐layered overburdens exhibiting Newtonian‐viscous rheologies. This program includes the following features: arbitrarily shaped interfaces between different fluid boundaries, layers of finite thickness and subsidence of the model within the model‐frame as well as time‐ and depth‐dependent material properties. This paper is concerned with single diapirs intruding upbuilt multilayered overburdens, the effect of a subsiding salt base due to pure downbuilding, and differential loading of gravitationally unstable distributions of mass. Variable density and viscosity of the overburden with depth control the shape and ascent rates of diapiric bodies. The subsidence history of “salt structures” dominates the development of maximum horizontal pressure gradients with time and thus the ascend histories of diapirs.

Positive fault inversion triggering ‘intrusive diapirism’: an analogue modelling perspective

“…Sokoutis et al. , 2000): The natural viscosity resulting from is of the order of 8 × 10 17 Pa s, which is well within the range of natural salt viscosities (10 16 to 10 20 Pa s; LeCompte, 1965; Jackson and Talbot, 1986; Koyi, 1988, 1991; Römer and Neugebauer, 1991; Nalpas and Brun, 1993; Podladchikov et al. , 1993).…”

Numerical modelling of rise and fall of a dense layer in salt diapirs

“…Many investigators numerically modelled different aspects of salt diapirism (e.g. Woidt 1978; Schmeling 1987; Romer & Neugebauer 1991). However, few studies have addressed the problem of down‐building and multicompositional salt structures.…”

Moment of inertia for rock blocks subject to bookshelf faulting with geologically plausible density distributions

“…Density usually increases linearly vertically downward, especially for most oceanic crust (Reid 1987), sediments in basins (Motavalli-Anbaran et al 2013), or even for the entire lithosphere (e.g., Xu et al 2016) including the deep crust (Zhang and Chen 1992). However, the reverse can also happen (Ebbing et al 2007 and its review) with depth, especially if evaporitic rocks are involved (Romer and Neugebauer 1991). An average density gradient can be 0.32 Mg m −3 km −1 (Carlson and Herrick 1990), or 13 ± 2 kg m −3 km −1 (Tenzer et al 2012).…”