Abstract
We use a Landscape Evolution Model (FastScape S2S) to explore the impact
of inherited topography in the foreland domain of a rising mountain
range on its stratigraphic architecture and sediment accumulation
history, inspired by the northern Pyrenean foreland. We simulate an
uplifting half mountain range, its foreland basin and forebulge, and
beyond, an open marine domain. We ran models with 4 different initial
reliefs in the foreland domain: an initially flat foreland domain at
sea-level, an elevated flat continental foreland (+300 m), a
pre-existing 1 km-deep and 100 km-wide bathymetry at the location of the
future foreland basin associated with a forebulge domain either at
sea-level or elevated at +300m. All models show a prograding
mega-sequence associated with building of mountain topography and
development of the flexural foreland basin and forebulge, coalescence of
alluvial fans at the foot of the range, progressive continentalization
of the foreland domain, and burial of the forebulge. An initially
elevated foreland domain ultimately produces a thinner foreland basin
while an initially deep foreland basin produces a thicker one. After
10-13 Myr, the initial relief of foreland domain is smoothed out and the
landscape does not exhibit a record of pre-existing relief. In contrast,
the stratigraphic architecture of the foreland basin allows to trace
inherited relief with deep marine sediments in the initially deep
foreland basin, marine sediments onlapping and then burying the
forebulge initially at sea-level, and continental sediments onlapping
and burying the initially elevated foreland domain. We compare these
interpretations to the Pyrenean retro-foreland.