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Geologic Map of the Scotts Mills, Silverton, and Stayton Northeast 7.5 Minute Quadrangles, Northwest Oregon: A Digital Database: Silverton Quadrangle

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

   Tolan, Terry, Beeson, Marvin, and Wheeler, Karen L. , 1999, Geologic Map of the Scotts Mills, Silverton, and Stayton Northeast 7.5 Minute Quadrangles, Northwest Oregon: A Digital Database: Silverton Quadrangle: U.S. Geological Survey Open-File Report 99-0141.

   Online Links:

   • <http://geopubs.wr.usgs.gov/open-file/of99-141/>

   Other_Citation_Details:

   ARC/INFO export format. All files 29MB. All data and plot files can also be downloaded.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -122.88

   East_Bounding_Coordinate: -122.75

   North_Bounding_Coordinate: 45.13

   South_Bounding_Coordinate: 45.00

3. What does it look like?

   <http://geopubs.wr.usgs.gov/open-file/of99-141/svsc.pdf> (PDF)

   A PDF representation of both Scotts Mills and Silverton quadrangles (sheet 1).

4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 1999

   Currentness_Reference: Publication of digital geologic map database

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: map

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a vector data set. It contains the following vector data types (SDTS terminology):

      • entity point
      • complete chain
      • GT-polygon composed of chains

   2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator

      Universal_Transverse_Mercator:

      UTM_Zone_Number: 10

      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996

      Longitude_of_Central_Meridian: -123

      Latitude_of_Projection_Origin: 0.0

      False_Easting: 500000

      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest unknown
      Ordinates (y-coordinates) are specified to the nearest unknown
      Planar coordinates are specified in meters

7. How does the data set describe geographic features?

   SLV_GEO.PAT

   Silverton Geologic map units (Source: OFR-99-0141)

   PTYPE

   Polygon type (Source: OFR-99-0141)

   Value	Definition
   Qal	Alluvial deposits (Holocene)
   Qoal	Qoal
   Tfsh	Basalt of Sand Hollow (middle Miocene) - Frenchman Springs Member, Wanapum Basalt
   Tfsf	Basalt of Silver Falls (middle Miocene) - Frenchman Springs Member, Wanapum Basalt
   Tgsb	Sentinel Bluffs member (middle Miocene) - Grande Ronde Basalt
   Tgww	Winter Water member (middle Miocene) - Grande Ronde Basalt
   Tgou	Ortley and Umtanum members (middle Miocene) - Grande Ronde Basalt
   Tsm	Scotts Mills Formation-undifferentiated (Oligocene to lower Miocene?) - Grande Ronde Basalt

   SLV_GEO.AAT

   Linear geologic map features (Source: OFR-99-0141)

   LTYPE

   Line type (Source: OFR-99-0141)

   Value	Definition
   contact, inferred	contact whose position is not known and inferred
   fault, concealed	Concealed and inferred fault
   map boundary	Outside boundary of mapped area
   normal fault, concealed	A normal fault whose position is concealed and inferred
   normal fault, concealedm	Mainly concealed normal fault
   normal fault, inferred	A normal fault whose position was not observed and inferred
   normal fault, inferredm	A normal fault whose position is mainly(?) inferred.

   SLV_GEO.PAT

   Geologic unit at specific points (Source: OFR-99-0141)

   PTYPE

   Point Type (Source: OFR-99-0141)

   Value	Definition
   Qal	Alluvial deposits (Holocene)
   Qoal	Qoal
   Tfsh	Basalt of Sand Hollow (middle Miocene) - Frenchman Springs Member, Wanapum Basalt
   Tfsf	Basalt of Silver Falls (middle Miocene) - Frenchman Springs Member, Wanapum Basalt
   Tgsb	Sentinel Bluffs member (middle Miocene) - Grande Ronde Basalt
   Tgww	Winter Water member (middle Miocene) - Grande Ronde Basalt
   Tgou	Ortley and Umtanum members (middle Miocene) - Grande Ronde Basalt
   Tsm	Scotts Mills Formation-undifferentiated (Oligocene to lower Miocene?) - Grande Ronde Basalt

   SLV_STX.AAT

   Linear structural features (Source: OFR-99-0141)

   LTYPE

   Line type (Source: OFR-99-0141)

   Value	Definition
   cross-section	cross-section line
   f.a., monocline, concealed	Monocline fold-axis that is concealed and inferred
   f.a., monocline, concealedm	Monocline fold-axis that is mainly(?) concealed
   f.a., monocline, inferred	Monocline fold-axis whose position is inferred.
   f.a., monocline, inferredm	Monocline fold-axis whose position is mainly(?) inferred.
   f.a., monocline, plunge	Plunging monocline fold-axis

   SCM_STX.PAT

   Information on a singular bedding type and position (Source: OFR-99-0141)

   PTTYPE

   Point type (Source: OFR-99-0141)

   Value	Definition
   bedding	bedding plane

   DIP

   Bedding Dip (Source: OFR-99-0141)

   Value	Definition
   30	Bedding plane has a dip of 30 degrees.

   STRIKE

   Bedding strike (Source: OFR-99-0141)

   Value	Definition
   323	Bedding plane has a strike of 323 degrees.

   SLV_NEAT.AAT

   Neatline for Silverton and Scotts Mills (Source: OFR-99-0141)

   LTYPE

   Line Type (Source: OFR-99-0141)

   Value	Definition
   map boundary	outline of mapped area around both Silverton and Scotts Mills quadrangles

   SLV_WELL.PAT

   well sample data (Source: OFR-99-0141)

   PTTYPE

   Point Type (Source: OFR-99-0141)

   Value	Definition
   well location	Location of sample well

   SAMPNO

   Sample number to identify well (Source: OFR-99-0141)

   Value	Definition
   ?	unknown sample number
   (blank)	no well information

   Range of values
   Minimum:	18259
   Maximum:	50652

   TOB

   elevation relative to sea level to top of basalt in feet (Source: OFR-99-0141)

   Range of values
   Minimum:	-529
   Maximum:	+215
   Units:	feet
   Resolution:	1

   Entity_and_Attribute_Overview:

   LINE TYPES
   
   GEOLOGY - SLV_GEO:
   contact, inferred
   fault, concealed
   map boundary
   normal fault, concealed
   normal fault, concealedm
   normal fault, inferred
   normal fault, inferredm
   
   STRUCTURE - SLV_STX:
   cross-section
   f.a., monocline, concealed
   f.a., monocline, concealedm
   f.a., monocline, inferred
   f.a., monocline, inferredm
   f.a., monocline, plunge
   
   NEAT - SLV_NEAT:
   map boundary
   

   Entity_and_Attribute_Detail_Citation: More information can be found in the included readme file.

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Terry Tolan
   • Marvin Beeson
   • Karen L. Wheeler

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Terry Tolan
   Portland State University
   Department of Geology, Portland State University
   Portland, Oregon 97207-0751
   USA
   

Why was the data set created?

This Open-File report is a digital geologic map database. This pamphlet serves to introduce and describe the digital data. There is no paper map included in the Open-File report. The report does include, however, PostScript plot files containing images of two geologic map sheets with explanation, as well as the accompanying text describing the geology of the area.

How was the data set created?

1. From what previous works were the data drawn?

   (source 1 of 1)

2. How were the data generated, processed, and modified?

   (process 1 of 1)

   Digital compilation
   Several different coverages were generated during the construction of each of the three geologic quadrangle maps. Negatives of USGS topographic bases and geologic mylar tracings were scanned at 400 dpi, 1-bit TIFF bi-level compression type 1 (uncompressed) with rows per strip = 12000 on an ANATEK rasterizing scanner, then images were converted to ESRI ARC/INFO grids. The raster grids were converted to vector coverages with ARC/INFO's gridline routine. Alacarte and some custom menus and amls were used to project, transform, edit, tag and build, lines, polygons, and points in each map. A digital layout or map collar was made with Adobe Illustrator. The plot amls run in ARC/INFO and call the coverages, grids, and EPS to make uncompressed PostScript files. All maps are in UTM projection, zone 10, units meters, 1:24,000 scale. The pamphlet that describes the geology is saved to EPS from Microsoft Word.
   Base maps
   The source of the base maps used is the U.S. Geological Survey, 1:24,000 scale topographic maps, which have a 10-foot contour intervals (provisional edition, 1987). One base map layer for each of the three 7.5 minute quadrangles was prepared from negatives. Topographic bases for Scotts Mills, Silverton, and Stayton NE quadrangles were scanned on an Ideal rasterizing scanner at 400 dpi as 1-bit TIFF images. Scanned TIFF images of the bases were registered and rectified in ARC/INFO and then made into grids. The images were clipped using ARC/INFO grid to conform to the area of the geologic coverages and merged with the geology grid to give an apparent transparent color image of both combined. These base map-geology layers are digital images but no information other than location is attached to the lines. The base-geology maps are provided for reference only.
   

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

2. How accurate are the geographic locations?

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   This digital database represents the general distribution of bedrock and surficial deposits of the Scotts Mills, Silverton, and Stayton NE 7.5 minute quadrangles along the eastern margin of the Willamette Valley and adjacent lower foothills (Waldo and Silverton Hills) of the Cascade Range. The major emphasis of this investigation was to identify and map Columbia River Basalt Group (CRBG) units within the Scotts Mills, Silverton, and Stayton NE quadrangles and to utilize this detailed CRBG stratigraphy to identify and characterize structural features.

5. How consistent are the relationships among the observations, including topology?

   This digital map database was compiled from previously published and unpublished data and new mapping by the authors.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none

Use_Constraints: none

1. Who distributes the data set? (Distributor 1 of 1)
   U.S. Geological Survey Information Services
   Box 25248, Denver Federal Center
   Denver, CO 80255-0286
   USA
   

   1-888-ASK-USGS (voice)
   1-303-202-4693 (FAX)
   infoservices@usgs.gov
   

2. What's the catalog number I need to order this data set?

   USGS Open-File Report 99-0141

3. What legal disclaimers am I supposed to read?

   This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
   This database, identified as "Geologic Map of the Scotts Mills, Silverton, and Stayton Northeast 7.5 Minute Quadrangles: A Digital Database" has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Scotts Mills quadrangle: scm_geo.e00 - Geology polys, contacts, faults, polygon labels ptype = geology formation scm_stx.e00 - Geologic attitudes as points include pttype, strike, dip fields, dip values as annotation, fold axis as arcs, cross-sections as arcs in format Gzipped TAR files containing ARC/INFO export files. (version ARC/INFO version 7.2.1 for NT) Size: 10 megabytes
     Network links:	<http://geopubs.wr.usgs.gov/open-file/of99-141/sssofr.tar.gz>

   • Cost to order the data: none

   • Availability in non-digital form:

     These maps can be downloaded as a 81 megabyte PostScript file from: <http://geopubs.wr.usgs.gov/open-file/of99-141/sssofrps.tar.gz>
     These maps can also be downloaded as a 33 megabyte PDF file from: <http://geopubs.wr.usgs.gov/open-file/of99-141/sssofrpdf.tar.gz>

   • Cost to order the data: none

5. Is there some other way to get the data?

   Database files, PostScript plotfiles, and related files can be obtained by sending a tape with request and return address to:
   

   NW Oregon, Scotts Mills, Silverton, Stayton NE Geologic Map Plot files
   c/o Database Coordinator
   U.S. Geological Survey
   345 Middlefield Road, M/S 975
   Menlo Park, CA 94025
   

   Do not omit any part of this address!
   NOTE: Be sure to include with your request the exact names, as listed above, of the tar files you require. An Open-File Report number is not sufficient, unless you are requesting both the database package and plot file package for the report. The compressed tar file will be returned on the tape. The acceptable tape types are: 2.3 or 5.0 GB, 8 mm Exabyte tape.

Who wrote the metadata?

Dates:

Last modified: 24-Jul-2000

Metadata author:

Jennifer Lenz
US Geological Survey
12201 Surise Valley Drive, Mail Stop 918
Reston, VA 20192
USA

703-648-6974 (voice)
703-648-6560 (FAX)
pschweitzer@usgs.gov

Metadata standard:

Content for Digital Geospatial Metadata (FGDC-STD-001-1998)