Geology Reference
In-Depth Information
Fig. 7.4
MODIS satellite images of two major tide-dominated
delta systems, (
a
) the Changjiang river delta taken near the end
of the fl ood season on 25 October 2000 and (
b
) the Ganges-
Brahmaputra river delta taken late in the dry season on 19 March
2002. Major geographic and physiographic features of the delta
and surrounding areas are labeled. Both images show high
suspended sediment concentrations that extend 50-100 km off-
shore and hundreds of kilometers alongshore, largely due to
suspension by tidal currents (Images from NASA MODIS,
http://modis.gsfc.nasa.gov/
)
sediment fl uxes and persistent tidal energy sustain
high suspended-sediment concentrations offshore,
where these particulates are subject to widespread dis-
persal by coastal and ocean currents that are normally
too slow for entraining sediments without the addition
of a tidal-velocity component (Fig.
7.4
). Overall,
though, tide-dominated deltas bear the mark of not
only strong tidal infl uence, but also fl uvial and marine
processes that play critical roles in defi ning the charac-
ter and behavior of these complex margin systems.
