Albertz, M., and C. Beaumont (2010), An Investigation of Salt
Tectonic Structural Styles in the Scotian Basin, offshore Atlantic
Canada: Paper 2, Comparison of Observations with Geometrically Complex
Numerical Models, Tectonics (in press)
- Markus Albertz
Department of Oceanography,
Dalhousie University,
Halifax, Canada
Now at: ExxonMobil Upstream Research Company, Houston, USA
- Chris Beaumont
Department of Oceanography,
Dalhousie University,
Halifax, Canada
The auxiliary material contains 22 animated gif files showing
the evolution of the numerical models presented in our second (Paper
2) of two articles on the structural styles associated with salt
tectonics in the Scotian Basin, offshore Eastern Canada.
- Animation_B-4.gif Animation
of Model B-4 (aggradation). The results illustrate the behavior of
salt when the basin boundaries have tapers of ca. 3{degree
sign}. Salt flows and thickens seaward. Overburden rotates during
uplift.
- Animation_B-5.gif Animation
of Model B-5 (progradation). Seaward motion of salt is primarily
accommodated by an expulsion roller against the rear of the
advancing salt and eventually a salt sheet breaks out.
- Animation_B-6.gif
Animation of Model B-6 (aggradation). The results illustrate how
salt can flow over a seaward basement step up without hindrance.
- Animation_B-7.gif
Animation of Model B-7 (progradation). Salt flows over the basement
step and thickens seaward. A salt sheet breaks out in the landward
direction. Salt expulsion creates type E minibasins and expulsion
trails.
- Animation_B-8.gif
Animation of Model B-8 (aggradation). The results show how a salt
diapir can emerge above a seaward basement step down. Salt flows
seaward and inflates both the landward and seaward half of the salt
basin. A salt diapir localizes above the basement step.
- Animation_B-9a.gif
Animation of Model B-9a (progradation). During progradation, the
salt diapirs are trapped under overburden.
- Animation_B-9b.gif
Animation of Model B-9b (progradation). Weaker overburden sediments
allow a salt sheet to emerge.
- Animation_B-10.gif
Animation of Model B-10 (aggradation). The results show how salt
flows in a basin which combine a step down and a step up. As in
Model B-8, a salt diapir localizes above the step down.
- Animation_B-11a.gif
Animation of Model B-11a (progradation). A salt sheet breaks out
toward the end of the model time.
- Animation_B-11b.gif
Animation of Model B-11b (progradation). Faster progradation causes
the sheet to break out ca. 38 Ma earlier.
- Animation_B-12.gif
Animation of Model B-12 (aggradation). The results illustrate the
effects of deep salt basins. As in previous models with seaward
basement step downs, a salt diapir forms above the step. Expulsion
of the deep salt creates a large listric normal fault.
- Animation_B-13a.gif
Animation of Model B-13a (progradation). Continued expulsion of the
deep salt creates type E minibasins and a salt sheet.
- Animation_B-13b.gif
Animation of Model B-13b(progradation). A seaward sedimentation
hiatus enhances the advance of the salt sheet.
- Animation_B-14.gif
Animation of Model B-14 (aggradation). The results illustrate how a
basement obstacle with a height that equals the salt thickness
divides the basin into two separate subbasins. Salt diapirs grow at
the seaward end of either subbasin.
- Animation_B-15a.gif
Animation of Model B-15a (progradation). The diapirs are
overwhelmed by the overburden and buried.
- Animation_B-15b.gif
Animation of Model B-15b (progradation). Weaker overburden allows a
salt sheet to form.
- Animation_B-16.gif
Animation of Model B-16 (aggradation). The results show the
influence of a wide basement obstacle with a height that equals half
the salt thickness. Salt flows efficiently seaward and above the
basement high. Salt in the landward portions is nearly completely
evacuated and it accumulates in the seaward deep portion of the
basin.
- Animation_B-17.gif
Animation of Model B-17 (progradation). Continued progradation may
expel a salt sheet.
- Animation_B-18.gif
Animation of Model B-18 (aggradation). The results show the effects
of a central basement step in tapered salt basins. Given the reduced
flow velocity of salt in the seaward half of the basin (here, the
salt thins seaward), a diapir emerges only in at the seaward end of
the landward subbasin.
- Animation_B-19.gif
Animation of Model B-19 (progradation). Although a pillow forms in
the seaward subbasin, both salt structures are buried.
- Animation_B-20.gif
Animation of Model B-20 (aggradation). Weaker sediments during the
aggradation phase cause salt to climb strata in the landward
subbasin.
- Animation_B-21.gif
Animation of Model B-21 (progradation). Once salt has advanced over
the basement step, it becomes part of the differential load which
expels salt from the seaward subbasin. Differential loading and
expulsion in the seaward subbasin results in highly complex salt
structures, including stacked welds.