Distant off-fault damage and gold mineralization: The impact of rock heterogeneity

Field observations have established that fault-related damage can occur at locations, far from the principal slip surface, which are well outside the fractured region currently predicted by models of fault damage. We use a finite element model to simulate fracture initiation due to fault linkage and...

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Bibliographic Details
Published in:Tectonophysics 2013-11, Vol.608, p.461-467
Main Authors: Moir, H., Lunn, R.J., Micklethwaite, S., Shipton, Z.K.
Format: Article
Language:English
Subjects:
Computer simulation
Damage
Fault zone
Faults
Gold
Heterogeneity
Mineralization
Numerical modeling
Rock
Stepover
Western Australia
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Summary:Field observations have established that fault-related damage can occur at locations, far from the principal slip surface, which are well outside the fractured region currently predicted by models of fault damage. We use a finite element model to simulate fracture initiation due to fault linkage and show how variations in rock properties allow off-fault damage to develop at surprisingly large distances away from the main fault. Off-fault damage continues to grow even after two adjacent, closely spaced fault segments have interacted and linked. We demonstrate that this process was important for the formation of fracture-hosted gold deposits in the Mount Pleasant goldfield, Western Australia. The strength of lithological contacts also has a significant impact on off-fault damage location and intensity. Our approach may go some way to explaining the non-intuitive distribution of mineralization in certain mineral systems, as well as being applicable to predict subsurface fracturing and fluid flow in hydrothermal/geothermal reservoirs. •Mechanical heterogeneity exerts first-order control on fracture/fault evolution.•Off-fault damage can develop at large distances from principal slip surfaces.•Damage continues to evolve even after linkage on adjacent stepovers.
ISSN:0040-1951
1879-3266
DOI:10.1016/j.tecto.2013.08.043