Fault Patterns Associated with Domes--An Experimental and Analytical Study

Abstract

Experimental (clay) and analytical models suggest that regional strain, either extension or compression, significantly affects the fault patterns produced by doming. Our models specifically simulate the shallow deformation produced by gentle doming of a homogeneous material with and without a simultaneously applied, regional horizontal strain. The models of circular domes show that without regional strain, normal faults develop on the crests and flanks. On the flanks, the normal faults have radial trends. With regional extension, normal faults on the crests of circular domes trend perpendicularly to the regional extension direction, whereas many normal faults on the flanks trend obliquely to it. Strike-slip faults trending 60° from the regional extension direction fo m near the peripheries. With regional compression, many normal faults on the crests and flanks of circular domes strike parallel with the regional compression direction. Strike-slip faults trending 30° from the regional compression direction also form on the flanks, and reverse faults striking perpendicularly to the regional compression direction develop on the peripheries. Our models show that regional strain affects the fault patterns produced by elliptical doming similarly. The fault patterns of our models resemble fault patterns of domed strata above salt diapirs and above uplifted blocks of basement.