Geologic map of Santa Cruz county, California: A digital database

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Frequently anticipated questions:

What does this data set describe?

Geologic map of Santa Cruz county, California: A digital database
This Open-File report is a digital geologic map database. This digital map database is prepared from a previously published map by Brabb (1989). The geologic map database delineates map units that are identified by general age, lithology and clast size following the stratigraphic nomenclature of the U. S. Geological Survey.
  1. How might this data set be cited?
    Brabb, E. E., Graham, S. E., Wentworth, C., Knifong, D., Graymer, R., and Blissenbach, J., 1997, Geologic map of Santa Cruz county, California: A digital database: U.S. Geological Survey Open-File Report 97-489.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.33
    East_Bounding_Coordinate: -121.58
    North_Bounding_Coordinate: 37.29
    South_Bounding_Coordinate: 36.84
  3. What does it look like? (PDF)
    PDF representation of geologic map of Santa Cruz, California (5.7MB)
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1997
    publication date
  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
      UTM_Zone_Number: 10
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Planar coordinates are specified in meters
  7. How does the data set describe geographic features?
    Geologic map units (Source: OFR-97-489)
    Polygon type (Source: OFR-97-489)
    QtlColluvium (Holocene)
    QalAlluvial deposits, undifferentiated (Holocene)
    QbBasin deposits (Holocene)
    QbsBeach sand (Holocene)
    QtTerrace deposits, undifferentiated (Pleistocene)
    QesEolian deposits of Sunset Beach (Pleistocene)
    QclLowest emergent coastal terrace deposits (Pleistocene)
    QcuCoastal terrace deposits, undifferentiated (Pleistocene)
    QyfYounder flood-plain deposits (Holocene)
    QofOlder flood-plain deposits (Holocene)
    QyfoAlluvial fan deposits (Holocene)
    QdsDune sand (Holocene)
    QcfAbandoned channel fill deposits (Holocene)
    QemEolian deposits of Manresa Beach (Pleistocene)
    QwfFluvial facies (Pleistocene)
    QofAlluvial fan facies (Pleistocene)
    QceEolian facies - Coastal terrace deposits (Pleistocene)
    QclLowest emergent coastal terrace deposits - Coastal terrace deposits (Pleistocene)
    QarAromas Sand, undivided (Pleistocene)
    QaeEolian lithofacies - Aromas sand (Pleistocene)
    QafFluvial lithofacies - Aromas Sand (Pleistocene)
    QTcContinental deposits, undifferentiated (Pleistocene and Pliocene?)
    TpPurisima Formation (Pliocene and upper Miocene)
    TpsPredominantly massive sandstone
    TscSanta Cruz Mudstone (Upper Miocene)
    TsmSanta Margarita Sandstone (upper Miocene)
    TmMonterey Formation (middle Miocene)
    TloLompico Sandstone (middle Miocene)
    TlaLambert Shale (lower Miocene)
    TvqVaqueros Sandstone (lower Miocene and Oligocene)
    TbsBasalt (lower Miocene)
    TzZayanite Sandstone (Oligocene)
    TslSan Lorenzo Formation, undivided (Oligocene and Eocene)
    TsrRices Mudstone Member (Oligocene and Eocene)
    TstTwobar Shale Member (Eocene)
    TbuUpper sandstone member - Butano Sandstone (Eocene)
    TbmMiddle siltstone member - Butano Sandstone (Eocene)
    TblLower sandstone member - Butano Sandstone (Eocene)
    TblcConglomerate - Butano Sandstone (Eocene)
    TlLocatelli Formation (Paleocene)
    TlssSandstone - Locatelli Formation (Paleocene)
    TsSiltstone and sandstone (Pliocene and upper Miocene)
    TmpShale of Mount Pajaro area (Miocene and Oligoene)
    TmmSandstone of Mount Madonna area (Eocene?)
    TmsMudstone of Maymens Flat area (Eocene and Paleocene)
    KgsShale and sandstone of Nibbs Knob area (Upper Cretaceous)
    KcgConglomerate (Upper Cretaceous)
    qdQuartz diorite (Cretaceous)
    gaGranite and adamellite (Cretaceous)
    gdGneissic granodiorite (Cretaceous)
    hcgHornblende-cummingtonite gabbro (Cretaceous)
    schMetasedimentary rocks (Mesozoic or Paleozoic)
    mMarble (Mesozoic or Paleozoic)
    dbDiabase (age unknown)
    Linear features on geologic map (Source: OFR-97-489)
    Line type (Source: OFR-97-489)
    contact, approx. locatedContact whose position is not precisely known
    contact, certainObserved contact
    contact, inferredContact whose position is inferred
    fault, approx. locatedFault whose position is not precisely known
    fault, certainObserved fault
    fault, concealedConcealed fault whose position is inferred
    map boundary, certainBoundary of mapped area
    scratch boundaryLocation of scratch boundary
    scratch boundary, countylineLocation of countyline
    water boundaryBoundary of a body of water
    Geologic map units at specific locations (same attributes as polygon coverage SC-GEOL.PAT) (Source: OFR-97-489)
    Geologic fold axes (Source: OFR-97-489)
    Line type (Source: OFR-97-489)
    f.a., anticline, approx. locatedAnticlinal fold axis whose position is not precisely known
    f.a., anticline, certainObserved anticlinal fold axis
    f.a., anticline, concealedConcealed anticlinal fold axis whose position is inferred
    f.a., syncline, approx. locatedSynclinal fold axis whose position is not precisely known
    f.a., syncline, certainObserved synclinal fold axis
    f.a., syncline, concealedConcealed synclinal fold axis whose position is inferred
    Orientation of bedding and foliation (Source: OFR-97-489)
    Point type (Source: OFR-97-489)
    approx dip of beddingApproximate orientation of bedding plane
    beddingBedding plane orientation
    flat beddingBedding whose dip is practially horizontal
    foliationFoliation orientation
    ot beddingOverturned bedding plane orientation
    vert beddingVertical bedding plane orientation
    Dip of bedding or foliation (Source: OFR-97-489)
    Range of values
    Strike of bedding or foliation (Source: OFR-97-489)
    Range of values

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • E. E. Brabb
    • S. E. Graham
    • C. Wentworth
    • D. Knifong
    • R. Graymer
    • J. Blissenbach
  2. Who also contributed to the data set?
    I am most grateful to Joseph Clark, Indiana University, Pennsylvania, whose work forms the core of the County geology, and whose continual interest provides a rich resource to address unsolved problems. I am also grateful to William Dupre, University of Houston, for his help with the Quaternary geology, and to Thomas Dibblee, Jr., retired, and Robert McLaughlin for their work on the bedrock geology. Robert Smith kindly provided new information on a strand of the San Gregorio fault. David Burky, Kristin McDougall, William Sliter (deceased) and John Barron provided many identifications and ages for microfossils in an area characterized by poor outcrops, several formations with similar lithology, and complex structure.
  3. To whom should users address questions about the data?
    Brabb, Earl E
    Mail Stop 975, USGS
    345 Middlefield Road
    Menlo Park, CA

    650-329-5140 (voice)

Why was the data set created?

To provide a digital database of the Santa Cruz county, California to the public

How was the data set created?

  1. From what previous works were the data drawn?
    Brabb (1989) (source 1 of 1)
    Brabb, E.E., 1989, Geologic map of Santa Cruz County, California: U.S. Geological Survey Miscellaneous Investigations Series Map I-1905.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: 62500
    This database was digitized from this map of Santa Cruz, California.
  2. How were the data generated, processed, and modified?
    Date: 1991 (process 1 of 2)
    The geologic map information was digitized from a stable original of the geologic map at 1:62,500 scale. The author manuscript (ink on a greenline) was scanned using a monochrome scanner with a resolution of 800 dots per inch. The scanned image was vectorized and transformed from scanner coordinates to projection coordinates with digital tics placed by hand at latitude/longitude intersections. The scanned lines were edited interactively by hand using graphical user interface ALACARTE (Fitzgibbon, 1991, Fitzgibbon and Wentworth, 1991, Wentworth and Fitzgibbon, 1991). Scanning artifacts significant for display at a scale of 1:62,500 were corrected. The base map layer (sc-topo) was prepared by scanning a scale-stable clear film of the U.S Geological Survey, San Francisco Bay Region, sheet 3, 1:125,000 (1970) topographic map. The clear film was scanned using a monochrome scanner with a resolution of 400 dots per inch. The raster scan was converted to a GRID in ARC/INFO. The GRID was then vectorized and reprojected into UTM Projection using the latitude/longitude intersections as reference points. The arcs in the base layer have not been attributed.
    Date: 02-Aug-2000 (process 2 of 2)
    Creation of original metadata record Person who carried out this activity:
    Jennifer Lenz
    US Geological Survey
    12201 Surise Valley Drive, Mail Stop 918
    Reston, VA

    703-648-6974 (voice)
    703-648-6560 (FAX)
  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 observations, including topology?
    This digital map database is prepared from a previously published map by Brabb (1989).

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)
    USGS Information Services
    Box 25286, Denver Federal Center
    Denver, Colorado

    1-888-ASK-USGS (voice)
    1-303-202-4695 (FAX)
  2. What's the catalog number I need to order this data set? US Geological Survey Open-File Report 97-489
  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. 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 Santa Cruz County, California: A Digital Database," has been approved for release and publication by the Director of the USGS. Although this database has been reviewed and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. This database is released on condition that neither the USGS nor the U. S. Government may be held liable for any damages resulting from its use.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Depositional contacts and unit labels, Fold axes, strike and dip information, Topographic base map in format ARCE (version 7.x) Size: 9.8
      Network links:
    • Cost to order the data: none

Who wrote the metadata?

Last modified: 05-Feb-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse,
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA

703-648-6533 (voice)
703-648-6252 (FAX)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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