Gallery
A selection of seismic profiles
illustrating brittle and ductile
deformation structures
Normal Fault
The curved shape
makes this a listric
fault.
A listric shape is
very common.
Click to show
interpretation
Reverse fault
Click to show interpretation
Faults occur in complex patterns, this is block faulting
Click to show interpretation
Step faulting
Click to show interpretation
Stepped faults or monoclines?
Click to show interpretation
Unconformity
Click to show interpretation
Complex folding can be caused by the migration of salt.
Salt deformation offshore France
The salt body is coloured black
Image from the Virtual seismic Atlas www.seismicatlas.org
Author: TGS-Nopec
Salt dome Gulf of Mexico
Extreme deformation caused by very large quantities of low density salt migrating
towards the surface.
Image from the Virtual seismic Atlas www.seismicatlas.org
Author: Bruce Trudgill
Seismic data
poor here due
to the salt
(seismic
waves do not
get reflected
back to the
surface)
Salt diapir
has low
density
and moves
towards
the
surface
Salt dome Gulf of Mexico
Image from the Virtual seismic Atlas www.seismicatlas.org
Author: Bruce Trudgill
65 km
5000 msec
TWT
This is a thrust zone from offshore Namibia
It is a very large structure
The next slide shows a zoomed view
Image from the Virtual seismic Atlas www.seismicatlas.org
Author: Rob Butler
Thrust offshore Namibia
Image from the Virtual seismic Atlas www.seismicatlas.org
Author: Rob Butler
This map shows the location of Namibia.
Thrusts are low angle reverse faults commonly
associated with mountain building (orogenies).
Mountain building is associated with plate collisions.
This map shows the position of
the major plates.
Namibia is not near any colliding
plates.
BUT - it is near a place where
the continental crust meets
oceanic crust (passive margin).
What could be the mechanism
for this thrust zone?
It is driven by gravity