Families of Salt Domes in the Gulf Coastal Province

Abstract

If two fluids of different densities are superposed one over the other, the plane interface between the two fluids becomes unstable if the heavy fluid overlays the lighter one. This type of hydrodynamic instability is called Rayleigh‐Taylor instability. The theory of Rayleigh‐Taylor instability is a useful tool to study the distribution of salt domes in the coastal region of the Gulf Coastal Province. In spite of a drastic simplification of the geologic situation, the model shows: a) that the spacing of salt domes about an initial disturtbance depends upon the thickness of the mother salt and viscosity ratio of overlying sediment to salt; b) that domes not only grow upward from the initial disturbance, but domes are also triggered in the vicinity of the primary disturbance, forming a family of incipient domes with a regular pattern; c) that the family of incipient domes develops out of the initial disturbance starting at the location of maximal instability and spreading radially. Several numerical examples provide a framework for examining the disturbance of Gulf Coastal salt domes.

Nonlinear evolution of the Rayleigh–Taylor and Richtmyer–Meshkov instabilities

“…The duration determines the degree of nonlinearity and is characterized by l/y in the linear regime and a related scale evolution time in the nonlinear regime, Figure 1 shows fl vs h for various physical systems that exhibit hydrodynamic instability. These include the explosion of supernovae 117-81 and magnetized plasmas [9-141, magnetic confinement [15, 161 and solar layers [17], inertial confinement fusion [18,191 (ICF), the acceleration of metal plates [20-221, underground salt domes [23] and volcanic island arcs [24].…”

Numerical models of petroleum migration via buoyancy‐driven porosity waves in viscously deformable sediments

“…The value of the matrix shear viscosity of typical basinal sediments can vary over several orders of magnitude, and might thus be expected to allow for significant variation in possible model results. Based on studies of salt diapirism, shear viscosities of sediments fall largely within the range 10 17 À10 20 Pa s (Biot & Odé 1965;Mazariegos et al 1996;Poliakov et al 1996;Selig & Wermund 1966). Figure 6 shows the effect of the matrix viscosity on the wave behaviour.…”

“…1996; Poliakov et al . 1996; Selig & Wermund 1966). Figure 6 shows the effect of the matrix viscosity on the wave behaviour.…”

“…For example, in the Gulf of Mexico basin, salt underlies much of the region and has risen as diapirs through the overlying sediments. This widespread diapirism has long been recognized to signify viscous fluid behaviour in both the salt and the surrounding sediments (Arrhenius 1912;Nettleton 1934), implying viscosity values for the sediments most likely in the range of about 10 17 À10 20 Pa s (Biot & Odé 1965;Mazariegos et al 1996;Poliakov et al 1996;Selig & Wermund 1966). The fluid nature of the sediments is clearly seen in flow structures created during the diapirs' ascent, such as anticlinal drape folds overlying the diapirs (Curtis 1991) and synclinal drag folds lying adjacent to the diapirs (Ratcliff et al 1992).…”

“…1996; Poliakov et al . 1996; Selig & Wermund 1966). The fluid nature of the sediments is clearly seen in flow structures created during the diapirs' ascent, such as anticlinal drape folds overlying the diapirs (Curtis 1991) and synclinal drag folds lying adjacent to the diapirs (Ratcliff et al .…”