Publication Date:
2019
Description:
〈span〉As a primary driving force, margin tilting is crucial for gravity-driven thin-skinned salt
tectonics. We investigated how instant versus progressive margin tilting mechanisms influence
salt tectonics using an analogue modeling setup where tilting rate could be controlled.
Instant tilting resulted in initially high deformation rates, triggering widely distributed upslope
extension and downslope contraction. Later, both the extensional and contractional domains
migrated upslope as early extensional structures were successively deactivated, while deformation
rates decreased exponentially. In contrast, progressive tilting led to downslope migration
of the extensional domain by sequentially formed, long-lived normal faults. Contraction
localized on a few, long-lived thrusts before migrating upslope. We attribute the distinct
structural evolution of thin-skinned deformation, especially in the extensional domain, in
the two tilting scenarios mainly to mechanical coupling between the brittle overburden and
underlying viscous material. The coupling effect in turn is largely controlled by the deformation
rate. By demonstrating the spatiotemporal variations of structural style and kinematic
evolution associated with instant versus progressive tilting, we suggest that such variation is
identifiable in nature and therefore can provide a new way to analyze margin tilting histories.〈/span〉
Print ISSN:
0091-7613
Electronic ISSN:
1943-2682
Topics:
Geosciences