U.S. Geological Survey
2007
SEDTHICK_GRD - ESRI ArcRaster grid representing the isopach of Holocene surficial sediment within the inner shelf of Long Bay, South Carolina
1.0
raster digital data
Open-File Report
2005-1346
Woods Hole Science Center, Woods Hole, MA
U.S. Geological Survey, Coastal and Marine Geology Program
http://pubs.usgs.gov/of/2005/1346/arcgis/seismic_srf/sedthick_grd.zip
Baldwin, W.E.
Denny, J.F
Schwab, W.C.
Gayes, P.T.
Morton, R.A.
Driscoll, N.W.
2007
Geologic Framework Studies of South Carolina's Long Bay from Little River Inlet to Winyah Bay, 1999-2003; geospatial data release
1.0
Open-File Report
2005-1346
Woods Hole Science Center, Woods Hole, MA
U.S. Geological Survey, Coastal and Marine Geology Program
1 DVD-ROM
http://pubs.usgs.gov/of/2005/1346/
In 1999, the USGS, in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.
This data set contains an isopach surface depicting the thickness of Holocene surficial sediment within the inner shelf of Long Bay, offshore of the South Carolina Grand Strand. Chirp seismic data collected with Benthos SIS-1000 and Edgetech SB-512 acquisition systems were processed using SIOSEIS (Scripps Institute of Oceanography) and Seismic Unix (Colorado School of Mines) to produce segy files and jpg images of the profiles. Data were then imported into Landmark SeisWorks, a digital seismic interpretation package, where the sea floor and underlying transgressive surface (trans_grd) were interpreted and digitized. The isopach between these horizons was exported at every 50th shot as xyz points, and imported to ArcGIS for interpolation into a 10-m raster grid. Each Chirp system has a maximum vertical resolution of ~ 50 cm, so only values greater than 50 cm were used to produce the isopach grid. This does not mean that all no-data values within the grid are representative of no surficial sediment along the inner shelf, but does indicate that these areas likely contain accumulations of less than 50 cm.
1999
2003
ground condition
None planned
-79.159554
-78.515142
33.856092
33.188721
General
U.S. Geological Survey
USGS
Coastal and Marine Geology Program
CMGP
Woods Hole Science Center
WHSC
Seafloor
Marine Geology
Seismic Reflection Profile
Benthos SIS-1000
Edgetech SB-512
Chirp
ArcGIS Raster
Holocene
surficial sediment
isopach
ISO 19115 Topic Category
oceans
oceans and coastal
oceans and estuaries
geoscientific Information
General
Grand Strand
North Myrtle Beach
Myrtle Beach
Surfside
Garden City
Pawleys Island
Waites Island
Southeast United States
United States
Atlantic Ocean
None
These data should not be used at resolutions for which it is not intended. Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
http://pubs.usgs.gov/of/2005/1346/images/sedthick_grd.jpg
isopach of Holocene surficial sediment thickness within the Long Bay inner shelf
JPEG
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.780
No additional checks for topological consistency were performed on the data.
All available interpretations of Holocene surficial sediment are included in this data set.
Seismic navigation was by differential GPS; positional accuracy to less than 10 m
Seismic data are not corrected for tides. Thickness of Holocene surficial sediments was calculated as the distance between the seafloor and the underlying transgressive surface from interpretation of seismic reflection profiles.
Seismic profiles were interpreted in Landmark software. Each seismic profile was reviewed and acoustic reflectors representing the seafloor and underlying transgressive surface were digitized. An isopach representing Holocene surficial sediment was calculated.
2003
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
The isopach was exported as x,y,z (thickness values) and then imported to ArcGIS as point shapefiles.
2003
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
XYZ point data were used to generate a Triangulated Irregular Network surface using ARCGIS Create TIN and Edit TIN.
The resulting TIN surface was converted to a floating point grid using ARCGIS TIN to Raster, specifying the natural neighbors method and 100 meter cell size.
2003
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
Raster
Grid Cell
7283
5828
1
Universal Transverse Mercator
17
0.999600
-81.000000
0.00000
500000.000000
0.00000
row and column
100.00
100.00
meters
D_WGS_1984
WGS_1984
6378137.000000
298.257224
Mean lower low water
0.5
meters
Explicit depth coordinate included with horizontal coordinates
Thickness of Holocene sediment ESRI GRID format.
USGS
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
Downloadable Data
Although all data have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
ARCG
ArcGIS 9.0
ESRI ArcRaster GRID format
no compression applied
162.669
http://pubs.usgs.gov/of/2005/1346/arcgis/seismic_srf/sedthick_grd.zip
DVD-ROM
4.75
Gbytes
UDF
none
These data are available in Environmental Systems Research Institute (ESRI) GRID format. The user must have software capable of importing and processing the data file.
20070117
Wayne Baldwin
U.S. Geological Survey
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543
USA
508-548-8700 x2226
508-457-2310
wbaldwin@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
None
None
Online_Linkage: http://www.esri.com/metadata/esriprof80.html