Computational analysis of magma-driven dike and sill formation mechanisms

A computational model is described to simulate the magma-driven formation of dike and sill structures. This analysis can provide a number of forensic insights into the stress conditions that may exist in deep level mining operations or in the extraction of oil or gas reserves within a specific geotechnical environment. The paper describes the numerical simulation of a vertically propagating dike sheet and the subsequent intersection and fluid branching of magma into a horizontal plane of weakness (sill). This study represents a preliminary exploration of the intersection problem using a uniform fixed grid mesh which allows some insights to be gained into the field stress conditions that control the dike propagation through the plane of weakness or which can lead to the deflection of the magma flow and subsequent sill structure formation. An approximate method is introduced to represent the crack tip opening shape assuming zero toughness at the dike edges. Some future extensions to an unstructured moving element mesh representation are noted.