Entry_ID: (required) Entry_Title: Geologic map and digital database of the Porcupine Wash 7.5 minute quadrangle, Riverside County, California Group: Data_Set_Citation Originator(s): Robert E. Powell; Pamela M. Cossette (digital cartography) Title: Geologic map and digital database of the Porcupine Wash 7.5 minute 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/of01-030/ End_Group Keyword: geologic map Keyword: geology Keyword: surficial geology Keyword: bedrock geology Keyword: fault Keyword: erosion surface Keyword: pediment Keyword: soil Keyword: alluvial deposits Keyword: dike Keyword: batholith Keyword: metamorphic rocks Keyword: plutonic rocks Keyword: hypabyssal rocks Keyword: Pinto Gneiss Keyword: Augen gneiss of Monument Mountain Keyword: Granodiorite of Pinto Basin Keyword: Monzogranite of Cottonwood Pass Keyword: Monzodiorite of Munsen Canyon Keyword: Quartzite of Pinto Mountain Keyword: Dolomite of Iron Chief mine Keyword: Alluvium Group: Temporal_Coverage Start_date: 1973 Stop_date: 2000 End_Group Data_Set_Progress: Complete Group: Spatial_Coverage Southernmost_Latitude: 33.7499842 Northernmost_Latitude: 33.87499995 Westernmost_Longitude: -115.87509096 Easternmost_Longitude: -115.74990904 End_Group Location: southern California Location: Riverside County Location: Joshua Tree National Park Location: eastern Transverse Ranges Location: Eagle Mountains Location: Hexie Mountains Location: Cottonwood Mountains Location: Pinto Basin Location: Porcupine Wash 7.5' quadrangle Location: Hexie Mountains 15' quadrangle Location: Eagle Mountains 30 x 60' quadrangle Group: Data_Resolution Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 End_Group Access_Constraints: None Use_Constraints: Spatial Resolution. Use of this digital geologic map should not violate the spatial resolution of the data. The Porcupine Wash geologic map and database was developed using digital orthophotograph quarter quadrangles (DOQQs) as a base. DOQQs have a pixel resolution of 1 m and are accurate to a scale of 1:12,000 (1 in = 1,000 ft). Any enlargement beyond 1:12,000 exceeds the spatial resolution of the geologic data and should not be used in lieu of a more detailed site-specific geologic evaluation. Similarly, the digital topographic base map is derived from the U.S. Geological Survey, 1:24,000-scale Porcupoine Wash 7.5 minute quadrangle (provisional edition, 1986); any enlargement beyond 1:24,000 exceeds the spatial resolution of the topographic data. Plotting or viewing of the data at scales larger than 1:12,000 on the DOQQ base, or larger than 1:24,000 on the topographic base, will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Where the geologic data is used in combination with the topographic data, the resolution of the combined output is limited by the lower resolution of the topographic data. Where this database is used in combination with other data of higher resolution, the resolution of the combined output will be limited by the lower resolution of these data. Content. This database, identified as "Geologic map and digital database of the Porcupine Wash 7.5 minute quadrangle, Riverside County, California" has been approved for release and publication by the Director of the U.S. Geological Survey. 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 the condition that neither the USGS nor the United States Government may be held responsible for any damages resulting from its authorized or unauthorized use. This database 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. Faults. The Porcupine Wash database is sufficiently detailed to identify and characterize many actual and potential geologic hazards represented by faults, but 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, for example, Hart, 1988; Hart and Bryant, 1997). Hart, E. W., 1988, Fault-rupture zones in California; Alquist-Priolo Special Studies Zones Act of 1972 with index to special studies zones maps (revised, 1988): California Division of Mines and Geology Special Publication 42. Hart, E. W., and Bryant, W.A., 1997, Fault-rupture zones in California; Alquist-Priolo Special Studies Zones Act of 1972 with index to special studies zones maps (revised, 1997): California Division of Mines and Geology Special Publication 42. Originating_Center: (required) Group: Data_Center Data_Center_Name: U.S. Geological Survey Information Services Dataset_ID: USGS Open-File Report 01-30 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, CO 80225 USA End_Group End_Group End_Group Storage_Medium: SunOS, 5.6, sun4u UNIX ARC/INFO version 7.2.1 Group: Distribution Distribution_Media: online Distribution_Format : Arc/Info export Distribution_Size: 5.5 megabytes Fees: none End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-030/images/pwash_map.gif Format: GIF Group: Description Non-navigable .gif image of the geologic map, topographic base, Correlation of Map and Database Units, Description of Map and Database Units and key to point and line symbols. 64 kilobytes. End_Group End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-030/pwash_map.pdf Format: PDF Group: Description Navigable portable document file (.pdf) image of the geologic map, topographic base, Correlation of Map and Database Units, Description of Map and Database Units and key to point and line symbols. 5.4 megabytes. End_Group End_Group Group: Reference Citation_Information: Originator: Robert E. Powell Publication_Date: 2001 Title: Geologic map and digital database of the Conejo Well 7.5 minute quadrangle, Riverside County, California Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: USGS OF 01-31 Publication_Information: Publication_Place: Menlo park, California Publisher: U.S. Geological Survey Online_Linkage: End_Group Group: Summary The data set for the Porcupine Wash quadrangle has been prepared by the Southern California Areal Mapping Project (SCAMP), a cooperative project sponsored jointly by the U.S. Geological Survey and the California Division of Mines and Geology. The Porcupine Wash data set represents part of an ongoing effort to create a regional GIS geologic database for southern California. This regional digital database, in turn, is being developed as a contribution to the National Geologic Map Database of the National Cooperative Geologic Mapping Program of the USGS. The Porcupine Wash database has been prepared in cooperation with the National Park Service as part of an ongoing project to provide Joshua Tree National Park with a geologic map base for use in managing Park resources and developing interpretive materials. The digital geologic map database for the Porcupine Wash quadrangle has been created as a general-purpose data set that is applicable to land-related investigations in the earth and biological sciences. Along with geologic map databases in preparation for adjoining quadrangles, the Porcupine Wash database has been generated to further our understanding of bedrock and surficial processes at work in the region and to document evidence for seismotectonic activity in the eastern Transverse Ranges. The database is designed to serve as a base layer suitable for ecosystem and mineral resource assessment and for building a hydrogeologic framework for Pinto Basin. This data set maps and describes the geology of the Porcupine Wash 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province, encompasses parts of the Hexie Mountains, Cottonwood Mountains, northern Eagle Mountains, and south flank of Pinto Basin. It is underlain by a basement terrane comprising Proterozoic metamorphic rocks, Mesozoic plutonic rocks, and Mesozoic and Mesozoic or Cenozoic hypabyssal dikes. The basement terrane is capped by a widespread Tertiary erosion surface preserved in remnants in the Eagle and Cottonwood Mountains and buried beneath Cenozoic deposits in Pinto Basin. Locally, Miocene basalt overlies the erosion surface. A sequence of at least three Quaternary pediments is planed into the north piedmont of the Eagle and Hexie Mountains, each in turn overlain by successively younger residual and alluvial deposits. The Tertiary erosion surface is deformed and broken by north-northwest-trending, high-angle, dip-slip faults and an east-west trending system of high-angle dip- and left-slip faults. East-west trending faults are younger than and perhaps in part coeval with faults of the northwest-trending set. The Porcupine Wash database was created using ARCVIEW and ARC/INFO, which are geographical information system (GIS) software products of Envronmental Systems Research Institute (ESRI). The database consists of the following items: (1) a map coverage showing faults and geologic contacts and units, (2) a separate coverage showing dikes, (3) a coverage showing structural data, (4) a scanned topographic base at a scale of 1:24,000, and (5) attribute tables for geologic units (polygons and regions), contacts (arcs), and site-specific data (points). The database, accompanied by a pamphlet file and this metadata file, also includes the following graphic and text products: (1) A portable document file (.pdf) containing a navigable graphic of the geologic map on a 1:24,000 topographic base. The map is accompanied by a marginal explanation consisting of a Description of Map and Database Units (DMU), a Correlation of Map and Database Units (CMU), and a key to point-and line-symbols. (2) Separate .pdf files of the DMU and CMU, individually. (3) A PostScript graphic-file containing the geologic map on a 1:24,000 topographic base accompanied by the marginal explanation. (4) A pamphlet that describes the database and how to access it. Within the database, geologic contacts , faults, and dikes are represented as lines (arcs), geologic units as polygons and regions, and site-specific data as points. Polygon, arc, and point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic datum and link it to other tables (.rel) that provide more detailed geologic information. Map nomenclature and symbols Within the geologic map database, map units are identified by standard geologic map criteria such as formation-name, age, and lithology. The authors have attempted to adhere to the stratigraphic nomenclature of the U.S. Geological Survey and the North American Stratigraphic Code, but the database has not received a formal editorial review of geologic names. Special symbols are associated with some map units. Question marks have been added to the unit symbol (e.g., QTs?, Prpgd?) and unit name where unit assignment based on interpretation of aerial photographs is uncertain. Question marks are plotted as part of the map unit symbol for those polygons to which they apply, but they are not shown in the CMU or DMU unless all polygons of a given unit are queried. To locate queried map-unit polygons in a search of database, the question mark must be included as part of the unit symbol. Geologic map unit labels entered in database items LABL and PLABL contain substitute characters for conventional stratigraphic age symbols: Proterozoic appears as 'Pr' in LABL and as '<' in PLABL, Triassic appears as 'Tr' in LABL and as '^' in PLABL. The substitute characters in PLABL invoke their corresponding symbols from the GeoAge font group to generate map unit labels with conventional stratigraphic symbols. End_Group Group: Related_URL URL_Type: URL: Group: Description Originator: Robert E. Powell Publication_Date: 2001 Title: Geologic map and digital database of the Conejo Well 7.5 minute quadrangle, Riverside County, California Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: USGS OF 01-31 Publication_Information: Publication_Place: Menlo park, California Publisher: U.S. Geological Survey Online_Linkage: End_Group End_Group Group: DIF_Author Last_name: Cossette First_name: Pamela Middle_name: M. Email: pcossette@usgs.gov Phone: 509-368-3123 Group: Address U.S. Geological Survey West 904 Riverside Avenue Spokane, Washington 99201-1087 USA End_Group End_Group DIF_Revision_Date: 20010223 Science_Review_Date: