Sandbox Analogue Modelling Experiments: A Significant Tool to Interpret Tectonic Evolution of Basin Systems and Hydrocarbon Exploration
K. K. Agarwal
Centre of Advanced Study in Geology, University of Lucknow, Lucknow-226 007, India
Scaled sandbox analogue models have been used to simulate the growth of Coulomb thrust wedges in an overall contractional regime; development of orthogonal and oblique rift systems in extensional settings; development of pull-a-part basins in strike-slip setting and the inverted basins in extensional-compressional settings. These experiments are mainly carried out using isotropic cohesionless and anisotropic cohesionless materials, usually sand, to understand the development and evolution of thrust systems, hydrocarbon accumulation, tectonic and neotectonic activities in orogenic areas and other accretionary prisms.
Scaled sandbox analogue modelling experiments are done using a deforming material enclosed in a box, where deformation is either achieved by pushing the sandpack against the backstop or by pushing the backstop forward. A fan of dominantly foreland ward migrating thrust system develops within this box. These experiments demonstrate that in the natural systems the development of an orogen has significant relationship with the thrust activities. Both external and internal processes within naturally grown thrust systems can be compared with the results of these analogue models. These experiments have also been used to test the applicability of the critical wedge hypothesis. According to this, the thrust system develops in the form of a wedge (tapering at one end).
The internal and surface geometry of such wedges are controlled mainly by parameters like the coefficient of basal friction and the physical properties of the deforming materials.
A series of experiments have been carried out in the present study mainly in an overall contractional regime by using (i) three different basal detachment materials having different co-efficient of frictions (ii) combination of different detachment materials in one single experiment,(iii) change in the angle of the base plate, (iv) change in the back stop, and (v) the effects of erosion on a stable wedge.
Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery