A major component of the USGS-NC cooperative is to map the Quaternary
section within the Albemarle - Pamlico estuarine system and associated
barrier islands to develop the geologic framework and define the process
dynamics. The Albemarle - Pamlico Embayment is a large Quaternary
basin with a Holocene stratigraphic record. Previous investigations
show a record of non-steady state conditions through the Holocene
within the shallow, micro- to nanno-tidal estuarine system and the
intimately coupled, wave-dominated barrier-island system.
established that the post-glacial transgression was frequently interrupted
by millennial to centennial small-scale sea-level fluctuations driven
by some combination of changes in climatic and oceanographic processes.
These fluctuations resulted in multiple erosional and depositional
events. Episodes of lowered sea-level caused channel incisement
and erosional truncation within the estuarine system and regression
of the barrier-island system. Subsequent coastal flooding led to
deposition of estuarine sediments within the space and remobilization
of the barrier islands. The interrelationship between the underlying
paleodrainage framework and availability of sand on the shoreface
and inner shelf determines the character of the resultant barrier
island. Coastal segments form complex, wide, accretionary barriers
dominated by progradational beach ridges and back-barrier dune fields.
In comparison, sediment-starved (sand-poor) coastal segments develop
simple, narrow overwash barriers. There is a complex relationship
between sediment-rich barrier segments, related to trunk stream
valleys or interfluvial headlands, and sediment-starved, overwash
barrier segments, which are mostly related to tributary stream valley-fills
along the flanks of drainage basins. The principal goal of this
task is to define the Quaternary geologic framework and evolutionary
development of the back-barrier system.
1. Project area segments of back-barrier geologic
mapping program: Northeastern North Carolina.
Segment 1 to be completed in 2001;
Segment 2 - 2002; Segment 3 - 2003; Segment 4 - 2004.