USGS Geoscience Data Catalog
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Shroba, Ralph R. , and Scott, Robert B. , 2001, Geologic Map of the Silt Quadrangle, Garfield County, Colorado: U.S. Geological Survey Miscellaneous Field Studies Map MF-2331, U.S. Geological Survey, Denver, Colorado.Online Links:
This is a Vector data set.
The map projection used is Polyconic.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 10
Ordinates (y-coordinates) are specified to the nearest 10
Planar coordinates are specified in METERS
The horizontal datum used is North American Datum of 1927.
The ellipsoid used is Clarke 1866.
The semi-major axis of the ellipsoid used is 6378206.4.
The flattening of the ellipsoid used is 1/294.98.
SILTPOLY.AAT COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 FNODE# 4 5 B - 5 TNODE# 4 5 B - 9 LPOLY# 4 5 B - 13 RPOLY# 4 5 B - 17 LENGTH 8 18 F 5 25 SILTPOLY# 4 5 B - 29 SILTPOLY-ID 4 5 B - 33 LINECODE 3 3 I - 36 NAME 30 30 C - 66 SOURCE 4 4 I - 70 SYMBOL 3 3 I - SILTPOLY.PAT COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 AREA 8 18 F 5 9 PERIMETER 8 18 F 5 17 SILTPOLY# 4 5 B - 21 SILTPOLY-ID 4 5 B - 25 SOURCE 4 4 I - 29 LABEL 10 10 C - 39 DESC 100 100 C - 139 SYMBOL 3 3 I - SILTPOLY.CON COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 LINECODE 3 3 I - 4 SYMBOL 3 3 I - 7 TYPE 10 10 C - 17 MODIFIER 20 20 C - 37 CERTAINTY 15 15 C - 52 DESC 100 100 C - SILTPOLY.REF COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 SOURCE 4 4 I - 5 SCALE 8 8 I - 13 AUTHORS 200 200 C - 213 YEAR 4 4 I - 217 REFERENCE 250 250 C -siltline coverage: contains cross-section lines and a synclinal fold axis line. In the siltline.aat INFO file the NAME item indicates the name given to the structural feature. The SOURCE item contains the numeric code used to identify the data source for the structural feature. The DESC item contains the written description or explanation of the contact, boundary, or structural feature. The SYMBOL item contains the lineset symbol number used by ArcInfo to plot a line. The symbol numbers in this coverage refer to the geol_sfo.lin lineset.
SILTLINE.AAT COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 FNODE# 4 5 B - 5 TNODE# 4 5 B - 9 LPOLY# 4 5 B - 13 RPOLY# 4 5 B - 17 LENGTH 8 18 F 5 25 SILTLINE# 4 5 B - 29 SILTLINE-ID 4 5 B - 33 LINECODE 3 3 I - 36 NAME 30 30 C - 66 SOURCE 4 4 I - 70 DESC 100 100 C - 170 SYMBOL 3 3 I - SILTLINE.CON COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 LINECODE 3 3 I - 4 SYMBOL 3 3 I - 7 TYPE 10 10 C - 17 MODIFIER 20 20 C - 37 CERTAINTY 15 15 C - 52 DESC 100 100 C - SILTLINE.STR COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 LINECODE 3 3 I - 4 SYMBOL 3 3 I - 7 TYPE 10 10 C - 17 HORIZONTAL 20 20 C - 37 VERTICAL 20 20 C - 57 FOLD 15 15 C - 72 PLUNGE 15 15 C - 87 ACCURACY 15 15 C - 102 CERTAINTY 15 15 C - 117 DESC 100 100 C - SILTLINE.REF COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 SOURCE 4 4 I - 5 SCALE 8 8 I - 13 AUTHORS 200 200 C - 213 YEAR 4 4 I - 217 REFERENCE 250 250 C -siltpnt coverage: Contains points recording site-specific observations and measurements, such as strike and dip of bedding. In the siltpnt.pat INFO file the PTTYPE item lists the type of point symbol, e.g., strike and of inclined bedding. The MARKER item lists the markerset used for a particular PTTYPE. MARKER value 1 = GEOSCAMP2.MRK, 2 = OILGAS.MRK, 3 = USGS.MRK. OILGAS.MRK and USGS.MRK are standard ArcInfo markersets. The SYMBOLCD item lists the marker symbol used by ArcInfo to identify the type of structural map symbol. Symbol numbers refer to symbols in the 3 markersets listed above. The STRIKE item contains the strike of bedding. Strike is an azimuthal angle (measured in degrees from 0 to 360 in a clockwise direction from North). The DIP item contains the dip of bedding. This value is an angle measured (in degrees 0 to 90) down from the horizontal; thus a horizontal dip is 0 degrees and a vertical dip is 90 degrees. The CALCANG item contains an interim value used to calculate SYM$ANGLE. The SYM$ANGLE item is the angle used to mathematically rotate the map point symbol to its proper orientation on the map. This item was set equal to the pseudoitem '$ANGLE' (calc SYM$ANGLE = $ANGLE). The SOURCE item lists the numeric code used to identify the data source.
SILTPNT.PAT COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 AREA 8 18 F 5 9 PERIMETER 8 18 F 5 17 SILTPNT# 4 5 B - 21 SILTPNT-ID 4 5 B - 25 PTTYPE 80 80 C - 105 SYMBOLCD 3 3 I - 108 STRIKE 3 3 I - 111 DIP 3 3 I - 114 CALCANG 4 4 I - 118 SYM$ANGLE 4 4 I - 122 MARKER 3 3 I - 125 SOURCE 4 4 I - SILTPNT.REF COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 SOURCE 4 4 I - 5 SCALE 8 8 I - 13 AUTHORS 200 200 C - 213 YEAR 4 4 I - 217 REFERENCE 250 250 C -Auxiliary files:
Database root name: silt Label Desc af Artificial fill (latest Holocene) Qfp Flood-plain and stream-channel deposits (Holocene and late Pleistocene) Qty Younger terrace alluvium (late Pleistocene) Qtm Intermediate terrace alluvium (late Pleistocene) Qto Older terrace alluvium (late middle Pleistocene) Qba Basaltic alluvium (late middle Pleistocene) Qg Gravelly alluvium (late and middle Pleistocene) Qtt Oldest terrace alluvium (middle Pleistocene) Qfy Younger fan-alluvium and debris-flow deposits (Holocene and latest Pleistocene) Qac Alluvium and colluvium, undivided (Holocene and late Pleistocene) Qp Pediment deposits (middle Pleistocene) Qc Colluvium, undivided (Holocene to middle? Pleistocene) Qsw Sheetwash deposits (Holocene and late Pleistocene) Qsw/Qlo Sheetwash deposits over loess Qls Landslide deposits (Holocene to middle? Pleistocene) Qd Debris-flow deposits (Holocene? to middle? Pleistocene Qdo Older debris-flow deposits (early? Pleistocene) Qlo Loess (late and middle? Pleistocene) Qlo/Qty Loess over younger terrace alluvium Qlo/Qtm Loess over intermediate terrace alluvium Qlo/Qto Loess over older terrace alluvium Qlo/Qd Loess over debris-flow deposits Qlo/Qtt Loess over oldest terrace alluvium Qlo/Qp Loess over pediment deposits Qlo/Qtt/Qp Loess over oldest terrace alluvium over pediment deposits Tw Wasatch Formation (in cross section only) (Eocene to Paleocene) Tws Shire Member of Wasatch Formation (Eocene) Twss Sandstone unit of Shire Member of Wasatch Formation Twm Molina Member of Wasatch Formation (Eocene) Twa Atwell Gulch Member of Wasatch Formation (in cross section only) (Paleocene) Twav Volcaniclastic-rich unit of Atwell Gulch Member of Wasatch Formation Twal Lower unit of Atwell Gulch Member of Wasatch Formation Kmv Mesaverde Group (in cross section only) (Upper Cretaceous) Kwf Williams Fork Formation of Mesaverde Group Kwfu Upper unnamed sandstone unit of Williams Fork Formation of Mesaverde Group Kwfl Lower unnamed sandstone unit of Williams Fork Formation of Mesaverde Group Ki Iles Formation of Mesaverde Group Kir Rollins Sandstone Member of Iles Formation of Mesaverde Group Kicc Cozzette Sandstone and Corcoran Sandstone Members, undivided, of the Iles Formation of Mesaverde Group Kmvb Baked zone in the Mesaverde Group Kmu Mancos Shale, Upper member (Upper Cretaceous) DEFINITION OF LINECODES IN THE COVERAGES (LINECODES AND DESC IN THE .CON AND .STR FEATURES IN THE DATABASE------------------------- LINECODE | DESC 1 | contact; certain 2 | contact; approximately located 41 | water boundary 81 | map boundary (lines of latitude or longitude) 88 | limit of overturned strata 98 | cross-section line 413 | fold axis; syncline; certain
303-236-1292 (voice)
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To update and reinterpret earlier geologic mapping, and to provide sufficient geologic information for land-use decisions.
Shroba, Ralph R. , Fairer, George M. , and Green, Morris W. , 1994, Preliminary Geologic Map of the SILT Quadrangle, Garfield County, Colorado: U.S. Geological Survey Open-File Report 94-696, U.S. Geological Survey, Denver, CO.Online Links:
Data were entered and checked by the geologist that made the
field observations. The attributes of this geospatial data set
consist of text identifiers and numeric codes that indicate the
identity of the geologic unit or type of geologic feature, and
determine how each feature is colored or symbolized. To check
attribute accuracy, a color check plot was visually compared to
the geologist's original compilation. Discrepancies between the
digital geospatial dataset and the original analog compilation
were corrected as needed. Machine-created listings of unique
attribute values were used to identify spelling errors or other
inconsistencies, and corrections were made as needed. This map
has been thoroughly reviewed for conformity with U.S. Geological
Survey editorial standards and stratigraphic nomenclature.
Lines were primarily positioned by photointerpretation of
aerial photographs by using a PG-2 photogrammetric plotter that
rectified the position and transferred it to a basemap. Lines
were digitized from the basemap by using a digitizer tablet
having a resolution of 0.001 inch. Additional lines and point
observations were added in the field by means of positions
determined by a PLGR-95 GPS unit having accuracy of about 10
meters. Most positions on the map are estimated to be accurate
closer than 30 m horizontally.
Data are complete: no features that could be accurately represented
at the compilation scale of 1:24,000 were eliminated or
generalized. The smallest area represented is approximately 102
square meters. All geospatial database elements are attributed.
Map elements were visually checked for overshoots, undershoots,
duplicate features, polygon closure, and other errors by the author
and by the GIS technician(s) that created the digital database.
Automated (ArcInfo) routines were also used to check the databases
for polygon label errors, line or point attribution errors, sliver
polygons, dangling arcs, intersection errors, and projection
information. Check plots of the map were reviewed by at least two
other geologists for consistency with basic geologic principles and
general conformity to USGS mapping standards.
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints:
- none. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
303-236-5486 (voice)
webmaster@greenwood.cr.usgs.gov
USGS Miscellaneous Field Studies Map MF-2331
Although this digital spatial data has been subjected to rigorous review and is substantially complete, it is released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Data format: | Geologic units as polygons and structural features as lines in format Arc/Info export files and ArcView shapefiles (version ArcInfo version 8.0.2) Size: 3 megabytes |
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Network links: |
<http://greenwood.cr.usgs.gov/pub/mf-maps/mf-2331/mf-2331.tar.gz> |
1-888-ASK-USGS (voice)
MF-2331 (Map-on-Demand)
none
Available as one printed sheet plus one pamphlet. Order from USGS at the address listed above or see <http://rmmcweb.cr.usgs.gov/public/mod/order.html> for more ordering information.
for current prices please see <http://rmmcweb.cr.usgs.gov/public/mod/order.html>
303-236-1292 (voice)
rshroba@usgs.gov