Geologic Map of the Riverside East 7.5' Quadrangle, Riverside County, California

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What does this data set describe?

Geologic Map of the Riverside East 7.5' Quadrangle, Riverside County, California
This data set maps and describes the geology of the Riverside East 7.5' quadrangle, Riverside County, California. Created using Environmental Systems Research Institute's ARC/INFO software, the data base consists of the following items: (1) a map coverage containing geologic contacts and units, (2) a coverage containing structural data, (3) a coverage containing geologic unit annotation and leaders, and (4) attribute tables for geologic units (polygons), contacts (arcs), and site-specific data (points). In addition, the data set includes the following graphic and text products: (1) a postscript graphic plot-file containing the geologic map, topography, cultural data, a Correlation of Map Units (CMU) diagram, a Description of Map Units (DMU), and a key for point and line symbols, and (2) PDF files of the Readme (including the metadata file as an appendix), and the graphic produced by the Postscript plot file.
The Riverside East quadrangle is located in the northern part of the Peninsular Ranges Province within the central part of the Perris block, a relatively stable, rectangular in plan area located between the Elsinore and San Jacinto fault zones.
The quadrangle is underlain predominantly by Cretaceous plutonic rocks which are part of the composite Peninsular Ranges batholith. Within the quadrangle, the batholithic rocks represent a wide variety of mafic to intermediate composition granitic rocks ranging in composition from monzogranite to gabbro, but tonalite predominates. Most of the granitic rocks are faintly to intensely foliated. Many are heterogenous and contain varying amounts of meso-and melanocratic discoidal-shaped inclusions. Some rock is composed almost wholly of inclusion material and some are migmatitic. Included within these granitic rocks are a few septa of Paleozoic(?) biotite schist, marble, and calcsilicate rock of upper amphibolite metamorphic grade.
Metamorphic rocks of Paleozoic(?) age occur primarily in the northwest part of the quadrangle. These rocks include coarse-grained marble bodies that have been quarried in the past. North Hill, at the northwest corner of the quadrangle is the site of the 'Old City' quarry, where tonalite intrudes marble producing pyroxene-hornfels grade garnet-pyroxene skarn. South of Riverside several disconnected bodies of marble, impure quartzite, and calcsilicate rock were quarried at the 'New City' (Victoria Ave) quarry. There, the thicker of the two marble bodies was quarried exposing skarn developed at a contact between the marble and intrusive biotite-hornblende tonalite. The composition of the skarn is highly varied and includes pyroxene-grarnet, idocrase, scapolite-pyroxene, and magnetite-pageite skarns.
Biotite-hornblende tonalite of the relatively large Val Verde pluton dominates the quadrangle west of Interstate 215. In most places this tonalite has a northwest oriented crude to well developed planar fabric produced by oriented biotite and hornblende. In the northern part of the pluton northeast striking planar fabric dominates. Schlieren and massive clots of mafic tonalite occur locally. Discoidal-to pancake-shaped mafic inclusions are widespread and are oriented in the plane of the biotite and hornblende. Typically, the planar fabric dips moderately to the northeast, but is locally horizontal to subhorizontal or grades to an isotropic fabric.
Granitic rocks in the northeastern part of the quadrangle are part of the Box Springs plutonic complex. This composite intrusion is an elliptical, flat-floored granitic complex centered on the Box Springs Mountains. The exposed part of the complex is apparently the lower part of a granitic diapir. In the center of the complex massive to indistinctly primarily layered biotite tonalite grades outward into well foliated biotite tonalite. Further outward the rocks are a heterogeneous assemblage of primarily granodioritic plutonic rocks.
The geologic map data base contains original U.S. Geological Survey data generated by detailed field observation recorded on 1:24,000 scale aerial photographs. The map was created by transferring lines from the aerial photographs to a 1:24,000 scale topographic base. The map was digitized and lines, points, and polygons were subsequently edited using standard ARC/INFO commands. Digitizing and editing artifacts significant enough to display at a scale of 1:24,000 were corrected. Within the database, geologic contacts are represented as lines (arcs), geologic units are polygons, and site-specific data as points. Polygon, arc, and point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic datum.
  1. How might this data set be cited?
    Morton, Douglas M., and Cox, Brett F., 2001, Geologic Map of the Riverside East 7.5' Quadrangle, Riverside County, California: U.S. Geological Survey Open-File Report 01-452, U.S. Geological Survey, Menlo Park, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -117.3750914
    East_Bounding_Coordinate: -117.2499086
    North_Bounding_Coordinate: 33.99999995
    South_Bounding_Coordinate: 33.87498415
  3. What does it look like? (JPEG)
    Reduced-size image of the map, 400x538 pixels, 32-bit RGB true color, 89 kbytes. (PDF)
    Printable map sheet, 1.7 megabytes
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2001
    New data obtained
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  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):
      • Point (183)
      • String (458)
      • GT-polygon composed of chains (184)
    2. What coordinate system is used to represent geographic features?
      The map projection used is Polyconic.
      Projection parameters:
      Latitude_of_Projection_Origin: 33.875
      Longitude_of_Central_Meridian: -117.3125
      False_Easting: 0.00000
      False_Northing: 0.00000
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 1.0
      Ordinates (y-coordinates) are specified to the nearest 1.0
      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.
  7. How does the data set describe geographic features?
    Version 1.0 of the Riverside East 7.5' quadrangle comprises three ARC/INFO coverages, of which two contain geologic data, and one contains cartographic features: rse_geo (geology), rse_str (structural data), and rse_ano (annotation and leaders).
    Geologic data represented by line entities and the polygons they delineate are contained in the coverage RSE_GEO. For display purposes, the annotation coverage contains one annotation subclass: anno.geo contains unit labels.
    Geological point data includes site-specific information describing the types and the orientation of bedding, foliation, and lineations. Annotation is respective dip and plunge values associated with individual point data.
        1  AREA                   4    12     F      3
        5  PERIMETER              4    12     F      3
        9  RSE_GEO#               4     5     B      -
       13  RSE_GEO-ID             4     5     B      -
       17  PTYPE                 35    35     C      -
       52  LABL                  35    35     C      -
       87  PLABL                 35    35     C      -
      122  SHD                    3     3     I      -
      125  SHDFIL                 3     3     I      -
      128  NAME                 200   200     C      -
        1  FNODE#                 4     5     B      -
        5  TNODE#                 4     5     B      -
        9  LPOLY#                 4     5     B      -
       13  RPOLY#                 4     5     B      -
       17  LENGTH                 4    12     F      3
       21  RSE_GEO#               4     5     B      -
       25  RSE_GEO-ID             4     5     B      -
       29  LTYPE                 35    35     C      -
       64  L-SYMB                 3     3     I      -
    Geologic units (LABL) and their corresponding names (NAME) identified in the Riverside East 7.5' quadrangle
    geologic map unit label, in plain text
    KbaAmphibolitic gabbro of Box Springs plutonic complex
    KbfgBiotite granodiorite and tonalite of Box Springs plutonic complex
    KbfgiBiotite granodiorite and tonalite containing abundant inclusions, Box Springs plutonic complex
    KbftBiotite-hornblende tonalite of Box Springs plutonic complex
    KbgPorphyritic granodiorite of Box Springs plutonic complex
    KbgtHeterogeneous granodiorite and tonalite of Box Springs plutonic complex
    KbhgHeterogeneous porphyritic granodiorite of Box Springs plutonic complex
    Kbhg1Layered heterogeneous porphyritic granodiorite of Box Springs plutonic complex
    KbtBiotite tonalite of Box Springs plutonic complex
    KgGranitic dikes
    KgdGranodiorite, undifferentiated
    KgPzIntermixed schist and gneiss and granitic rocks
    KhgHeterogeneous granitic rocks
    KpGranitic pegmatite dikes
    KrgGranite of the Riverside area
    KtTonalite, undifferentiated
    KvtVal Verde tonalite
    Kvt?Val Verde tonalite
    PzcCalc-silicate rocks
    PzmsMarble and schist, undifferentiated
    PzqImpure quartzite
    PzsBiotite schist
    QTsUnnamed late Cenozoic sedimentary rocks in Riverside and Corona areas
    QafArtificial fill
    QofaOld alluvial fan deposits, arenaceous
    QvofaVery old alluvial fan deposits, arenaceous
    QyaaYoung axial channel deposits, arenaceous
    QyfaYoung alluvial fan deposits, arenaceous
    Geological map unit label used to generate plot labels with relevant stratigraphic symbols. The geologic units with LABL designating Mesozoic (Mz) have keystroke substitute characters, }, that call their corresponding symbols from the Stratagem Font Group. Geologic map unit labels will plot on derivative map plots with appropriate stratigraphic symbols if PLABL is used as the source for unit labels.
    polygon color (as integer value) from shadeset alc1.shd (included in the data package)
    polygon fill pattern (as integer value) from shadeset geology2.shd (included in the data package)
    Geologic name of map unit (see list under LABL attribute)
    Geologic features such as contacts and faults that bound rock-unit polygons
    Description of types of lines on the geologic map (contact, fault).
    contact, certain 
    fault, approx. located 
    fault, concealed 
    map boundary 
    stores appropriate line symbol value from the lineset geoscamp2.lin
    Geological point data includes site-specific information describing the types and the orientation of bedding, foliation, and lineations. One annotation subclass is included in the geologic points coverage, RSE_STR which displays the respective dip and plunge values associated with individual point data.
    describes type of point data (bedding, horizontal bedding, foliation)
    Coded integer value that relates point to cartographic point symbol in markerset geoscamp2.mrk
    Azimuthal strike of planar feature
    Dip of planar feature
    Annotation leaders
    Coded integer value (1) that relates arcs to cartographic line symbol in lineset geoscamp2.lin

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Douglas M. Morton
    • Brett F. Cox
  2. Who also contributed to the data set?
    Geologic mapping and digital preparation of this report were sponsored jointly by (1) the National Cooperative Geologic Mapping Program of the U.S. Geological Survey, (2) the California Division of Mines and Geology, (3) the Southern California Areal Mapping Project (SCAMP), and (4) the U.S. Air Force.
  3. To whom should users address questions about the data?
    Douglas M Morton
    U.S. Geological Survey, GEO-WRG-NGM
    UC - Riverside
    Riverside, CA

    909-276-6397 (voice)
    909-276-6295 (FAX)

Why was the data set created?

The data set for the Riverside East 7.5' quadrangle was prepared under the U.S. Geological Survey Southern California Areal Mapping Project (SCAMP) as part of an ongoing effort to develop a regional geologic framework of southern California, and to utilize a Geographic Information System (GIS) format to create regional digital geologic databases. These regional databases are being developed as contributions to the National Geologic Map Database of the National Cooperative Geologic Mapping Program of the USGS.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 1978 (process 1 of 6)
    Field mapping and aerial photograph interpretation; iterative process (D.M. Morton).
    Date: 1980 (process 2 of 6)
    Field mapping and aerial photograph interpretation; iterative process (B.F. Cox).
    Date: 1999 (process 3 of 6)
    Digitization of geologic linework and point data from a scale-stable cartographic base of quadrangle. ARC/INFO database established; cleanup of artifacts; polygon, arc, and point attribute tables established. Digitizing and editing artifacts significant enough to display at a scale of 1:24,000 were corrected (R.M. Alvarez and V.M. Diep).
    Date: 2001 (process 4 of 6)
    Description of map units and correlation of map units (F.K. Miller).
    Date: 03-Oct-2001 (process 5 of 6)
    First draft of metadata created by Michael J. Watson using FGDCMETA.AML ver. 1.2 05/14/98 on ARC/INFO data set /scamp26/mwatson/rse_ofr/rse_geo
    Date: 03-Oct-2001 (process 6 of 6)
    Creation of original metadata record Person who carried out this activity:
    U.S. Geological Survey
    Attn: Rachel M. H. Alvarez
    U.S. Geological Survey
    Riverside, California

    (909) 276-6397 (voice)
    (909) 276-6295 (FAX)
  3. What similar or related data should the user be aware of?
    Morton, D.M., 1999, Preliminary digital geologic map of the Santa Ana 30'x60' quadrangle, southern California, version 1.0.: U.S. Geological Survey Open-File Report 99-172, U.S. Geological Survey, California.

    Online Links:

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

  1. How well have the observations been checked?
    Geologic-map units in the Riverside East quadrangle database were described using standard field methods. Consistent with these methods, the database author has assigned standard geologic attributes to geologic lines, points, and polygons identified in the database.
    Nationwide geologic-map accuracy standards have not been developed and adopted by the U.S. Geological Survey and other earth-science entities. Until such standards are adopted, the SCAMP project has developed internal map-accuracy standards for 1:24,000-scale geologic maps produced by the project.
    Geologic lines and points on 1:24,000 scale geologic maps are judged to meet SCAMP's internal map-accuracy standards if they are located to within +/-15 meters, relative to topographic or cultural features on the base map.
    On any derivative geologic-map plot, line data that are judged to meet the SCAMP internal map-accuracy standard are denoted by solid lines; line data that may not meet the SCAMP internal map-accuracy standard are denoted by dashed or dotted lines. There is no cartographic device for denoting the map-accuracy for geologic-point data (e.g., symbols representing bedding, foliation, lineations, etc.).
  2. How accurate are the geographic locations?
    The maximum transformation RMS error acceptable for a 7.5' quadrangle transformation and data input is 0.003 (1.8 meters). Horizontal positional accuracy was checked by visual comparison of hard-copy plots with base-stable source data.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    The geologic map database of the Riverside East 7.5' quadrangle contains new data that have been subjected to rigorous review and are a substantially complete representation of the current state of knowledge concerning the geology of the quadrangle.
  5. How consistent are the relationships among the observations, including topology?
    Polygon and chain-node topology present.
    The areal extent of the map is represented digitally by an appropriately projected (polyconic projection), mathematically generated box. Consequently, polygons intersecting the lines that comprise the map boundary are closed by that boundary. Polygons internal to the map boundary are completely enclosed by line segments which are themselves a set of sequentially numbered coordinate pairs. Point data are represented by coordinate pairs.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None
The Riverside East 7.5' geologic-map database should be used to evaluate and understand the geologic character of the Riverside East 7.5' quadrangle as a whole. The data should not be used for purposes of site-specific land-use planning or site-specific geologic evaluations. The database is sufficiently detailed to identify and characterize many actual and potential geologic hazards represented by faults and landslides and posed by ground subsidence and earthquake-generated ground shaking. However, it is not sufficiently detailed for site-specific determinations or evaluations of these features. Faults shown do not take the place of fault-rupture hazard zones designated by the California State Geologist (see Hart, 1988).
Use of this digital geologic-map database should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. The fact that this database was compiled and edited at a scale of 1:24,000 means that higher resolution information may not have been uniformly retained in the dataset. Plotting at scales larger than 1:24,000 will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Similarly, although higher resolution data is incorporated in most of the map, the resolution of the combined output will be limited by the lower resolution data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey Information Services
    Box 25286 Denver Federal Center
    Denver, Colorado

    (303)202-4700 (voice)
    (303)202-4693 (FAX)
  2. What's the catalog number I need to order this data set? USGS Open-File Report 01-452
  3. What legal disclaimers am I supposed to read?
    The U.S. Geological Survey (USGS) provides these geographic data "as is." The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty.
    In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by USGS.
    This digital geologic map database of the Riverside East 7.5' quadrangle, 1:24,000 map-scale, and any derivative maps thereof, is not meant to be used or displayed at any scale larger than 1:24,000 (e.g., 1:12,000).
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Geologic units and structural features, with TIFF image of base map in format ARCE (version 7.2.1) Size: 2.1
      Network links:
    • Cost to order the data: none

Who wrote the metadata?

Last modified: 10-Jun-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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