Seminar on Deltas by Postdoctoral Scholar at Woods Hole Science Center
Deltas, sedimentary landforms that occur along continental margins where rivers discharge
sediment to the oceans, have been studied for many decades to understand their origins
and evolutionary history and as models for better understanding ancient buried delta
deposits that are important for energy exploration. Research has shown that such factors
as the volume of river-sediment discharge to the coast, the volume and direction of
long-shore transport, tidal range, sea-level history, and wave energy and direction
control the three-dimensional form and architecture of deltas.
Deltas are receiving renewed attention because they are low-relief regions, commonly
densely populated and important for agriculture and extremely vulnerable to accelerated
rise in relative sea level forecasted for the near future as a result of climate warming.
The USGS has conducted geologic framework and process studies of the 300-km-wide
Mississippi River delta plain for more than a decade to understand coastal erosion,
wetland loss due to complex natural and manmade processes, habitat change, and,
more recently, subsidence as a major factor in relative sea-level rise. Results from
these USGS studies are being used as baseline science information for the Louisiana
ecosystem-restoration program currently underway.
In a talk on February 20, 2002, entitled "Wave-Dominated Deltas," Liviu Giosan, a
postdoctoral fellow at the Woods Hole Oceanographic Institution (WHOI), presented
new ideas on the evolution and sedimentary records of wave-influenced deltas around
the world. In addition to reviewing past delta studies, Liviu presented results of his own,
ongoing research on the deltas of the Danube River (which flows into the Black Sea
off Romania) and the Brazos River (which flows into the Gulf of Mexico off Texas).
Liviu will continue his coastal research for the rest of his postdoctoral appointment
and will collaborate with USGS scientists and others to organize a delta session for
this fall's annual Geological Society of America meeting (Oct. 27-30, 2002,
non-profit research facility
in this issue:
African Sahel Dust
Radio Interview Explores African Dust
Florida Coastal Storm Defenses
Oceans Day 2002
Black History Month
Environmental Academy Web Site
Regional Science Fair
Congressional BriefingSea Otter Research
Law of the Sea
Bill Dillon Retires
John Hughes Clarke"Imaging Water Mass Variability"
March Publications List