Application of continuous-seismic reflection techniques to delineate paleochannels beneath the
Neuse River at U.S. Marine Corps Air Station, Cherry Point, North Carolina
Water-Resources Investigations Report 99-4099
By Alex P. Cardinell
Full Report (PDF, 36 pages, 11.2 Mb)
Abstract
A continuous seismic-reflection profiling survey was conducted by the
U.S. Geological Survey on the Neuse River near the Cherry Point Marine
Corps Air Station during July 7-24, 1998. Approximately 52 miles of
profiling data were collected during the survey from areas northwest of
the Air Station to Flanner Beach and southeast to Cherry Point.
Positioning of the seismic lines was done by using an integrated
navigational system.
Data from the survey were used to define and delineate paleochannel
alignments under the Neuse River near the Air Station. These data also
were correlated with existing surface and borehole geophysical data,
including vertical seismic-profiling velocity data collected in 1995.
Sediments believed to be Quaternary in age were identified at varying
depths on the seismic sections as undifferentiated reflectors and lack
the lateral continuity of underlying reflectors believed to represent
older sediments of Tertiary age. The sediments of possible Quaternary
age thicken to the southeast.
Paleochannels of Quaternary age and varying depths were identified
beneath the Neuse River estuary. These paleochannels range in width
from 870 feet to about 6,900 feet. Two zones of buried paleochannels
were identified in the continuous seismic-reflection profiling data.
The eastern paleochannel zone includes two large superimposed channel
features identified during this study and in re-interpreted 1995 land
seismic-reflection data. The second paleochannel zone, located west of
the first paleochannel zone, contains several small paleochannels near
the central and south shore of the Neuse River estuary between Slocum
Creek and Flanner Beach. This second zone of channel features may be
continuous with those mapped by the U.S. Geological Survey in 1995
using land seismic-reflection data on the southern end of the Air
Station.
Most of the channels were mapped at the Quaternary-Tertiary sediment
boundary. These channels appear to have been cut into the older
sediments and deepen in a southerly or downgradient direction. If
these paleochannels continue beneath the Marine Corps Air Station and
are filled with permeable sediment, they may act as conduits for
ground-water flow or movement of contaminants between the surficial
and underlying freshwater aquifers where confining units are breached.
Citation:
Cardinell, A.P., 1999, Application of continuous seismic-reflection techniques to delineate paleochannels beneath the Neuse River at U.S. Marine Corps Air Station, Cherry Point, North Carolina: U.S. Geological Survey Water-Resources Investigations Report 99-4099, 29 p.
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North Carolina Water Science Center
U.S. Geological Survey
3916 Sunset Ridge Road
Raleigh, North Carolina 27607
(919) 571-4000
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