Entry_ID: (required) Entry_Title: Geologic Map of the Steele Peak 7.5' Quadrangle, Riverside County, California Group: Data_Set_Citation Originator(s): Douglas M. Morton Title: Geologic Map of the Steele Peak 7.5' Quadrangle, Riverside County, California Publication: U.S. Geological Survey Open-File Report Publication_Date: 2001 Publication_Place: Menlo Park, California Publisher: U.S. Geological Survey Edition: Version 1.0 Data_Presentation_Form: vector digital data URL: http://geopubs.wr.usgs.gov/open-file/of01-449/ End_Group Keyword: geologic map Keyword: geology Keyword: bedrock geology Keyword: Cretaceous tonalite and granodiorite Keyword: Cretaceous volcanics Keyword: Cretaceous Group: Temporal_Coverage Start_date: 2001 Stop_date: 2001 End_Group Data_Set_Progress: Complete Group: Spatial_Coverage Southernmost_Latitude: 33.74998418 Northernmost_Latitude: 33.87499995 Westernmost_Longitude: -117.37509096 Easternmost_Longitude: -117.24990904 End_Group Location: California Location: Riverside County Location: Steele Peak 7.5' quadrangle Group: Data_Resolution Latitude_Resolution: 1.0 Longitude_Resolution: 1.0 End_Group Access_Constraints: None Use_Constraints: The Steele Peak 7.5' geologic-map database should be used to evaluate and understand the geologic character of the Steele Peak 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. Originating_Center: (required) Group: Data_Center Data_Center_Name: U.S. Geological Survey Information Services Dataset_ID: USGS Open-File Report 01-449 Group: Data_Center_Contact Last_name: U.S. Geological Survey Information Services First_name: N/A Phone: (303)202-4700 Group: Address Box 25286 Denver Federal Center Denver, Colorado 80225 USA End_Group End_Group End_Group Storage_Medium: SunOS, 5.8, sun4m UNIX ARC/INFO version 7.2.1 Group: Distribution Distribution_Media: online Distribution_Format : ArcInfo export Distribution_Size: 1.9 megabytes Fees: none End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-449/images/stp.jpg Format: JPEG Group: Description Reduced-size image of the map sheet, 400x586 pixels, 32-bit RGB true color, 85 kbytes. End_Group End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-449/stp_map.pdf Format: PDF Caption: Printable map sheet, 1.6 megabytes. End_Group Group: Reference Citation_Information: Originator: Morton, D.M. Publication_Date: 1999 Title: Preliminary digital geologic map of the Santa Ana 30'x60' quadrangle, southern California, version 1.0. Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 99-172 Publication_Information: Publication_Place: California Publisher: U.S. Geological Survey Online_Linkage: http://geopubs.wr.usgs.gov/open-file/of99-172/ End_Group Group: Summary The data set for the Steele Peak 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. This data set maps and describes the geology of the Steele Peak 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 Steele Peak 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 by Cretaceous and older basement rocks. Cretaceous plutonic rocks are part of the composite Peninsular Ranges batholith. A wide variety of mafic to intermediate composition granitic rocks occur in the quadrangle, and are mainly of tonalitic composition, but range from monzogranite to gabbro. Most rock units are faintly to intensely foliated, compositionally heterogenous, and contain varying amounts of meso-and melanocratic discoidal-shaped inclusions. Some rocks are composed almost wholly of inclusion material and some are migmatitic. Included within these granitic rocks are septa not shown on the geologic map of Paleozoic(?) schist of upper amphibolite metamorphic grade. Metamorphic rocks of primarily Mesozoic age occur in a discontinuous belt extending from the southeast to the northwest corner of the quadrangle. Most of these rocks are well foliated biotite-bearing schist. Near the southern edge of the quadrangle phyllitic rocks dominate. Northwestward, metamorphism increases from greenschist or sub-greenschist grade near the south edge of the quadrangle to sillimanite-bearing schist of upper amphibolite grade in the vicinity of Cajalco Road. Biotite-hornblende tonalite of the relatively large Val Verde pluton dominates the northeastern half of the quadrangle. In most places this tonalite has a northwest oriented crude to well developed planar fabric produced by oriented biotite and hornblende. Schlieren and massive clots of mafic tonalite locally occur. Discoidal- to pancake-shaped mafic inclusions are widespread and are oriented in the plane defined by the biotite and hornblende. This planar fabric typically dips moderately to the northeast, but locally shallows to a horizontal to subhorizontal planar fabric, or fades to an isotropic fabric. West of the Val Verde pluton are a number of plutons having fabrics ranging from massive isotropic to foliated. Compositions of these plutons range from monzogranite to pyroxene gabbro. Most of these granitic rocks fall within the composition range from monzogranite to tonalite, and are part of the composite Gavilan ring complex. Hypersthene is a characteristic mineral of most of the rocks of this complex, which includes black hypersthene-bearing monzogranite that has been quarried as a source of 'black granite' building stone. Several inactive gold mines, e.g., Goodhope, Gavilan, and Santa Rosa mines that constituted the Pinacate mining district, are located in the Gavilan ring complex. In the center of the Gavilan ring complex is the near circular Arroyo del Toro pluton, a massive-textured granodiorite essentially devoid of inclusions. Only the northern half of this pluton is located in the quadrangle. Some rock of this pluton was quarried for building stone. The southwestern corner of the quadrangle is underlain by siliceous volcanic and volcanoclastic rock considered to be coeval with the batholith and be the supra-part of the batholithic magmatism. Most of these volcanic rocks range in composition from rhyolite to andesite with latitic composition rocks predominating. In the northeastern part of the quadrangle is the proximal parts of a Pleistocene alluvial fan complex. 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. End_Group Group: Related_URL URL_Type: URL: http://geopubs.wr.usgs.gov/open-file/of99-172/ Group: Description Originator: Morton, D.M. Publication_Date: 1999 Title: Preliminary digital geologic map of the Santa Ana 30'x60' quadrangle, southern California, version 1.0. Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 99-172 Publication_Information: Publication_Place: California Publisher: U.S. Geological Survey Online_Linkage: http://geopubs.wr.usgs.gov/open-file/of99-172/ End_Group End_Group Group: DIF_Author Last_name: Alvarez First_name: Rachel Middle_name: M.H. Email: rhauser@usgs.gov Phone: (909) 276-6397 Group: Address U.S. Geological Survey Department of Earth Sciences University of California, Riverside Riverside, California 92521 USA End_Group End_Group DIF_Revision_Date: 20010919 Science_Review_Date: