Entry_ID: (required) Entry_Title: Geologic Map of the Telegraph Peak 7.5' quadrangle, San Bernardino County, California Group: Data_Set_Citation Originator(s): Douglas M. Morton; M.O. Woodburne; J.H. Foster Title: Geologic Map of the Telegraph Peak 7.5' quadrangle, San Bernardino 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/of01-293 End_Group Keyword: geologic map Keyword: geology Keyword: bedrock geology Keyword: surficial geology Keyword: San Andreas Fault Keyword: San Jacinto Fault Keyword: San Gabriel Mountains Keyword: Pelona Schist Group: Temporal_Coverage Start_date: 19740401 Stop_date: 19810801 End_Group Data_Set_Progress: Complete Group: Spatial_Coverage Southernmost_Latitude: 34.24998407 Northernmost_Latitude: 34.37499995 Westernmost_Longitude: -117.6250927 Easternmost_Longitude: -117.4999073 End_Group Location: California Location: San Bernardino County Location: Telegraph 7.5' quadrangle Group: Data_Resolution Latitude_Resolution: 0.0027669065166 Longitude_Resolution: 0.0027669065166 End_Group Access_Constraints: None Use_Constraints: The Telegraph 7.5' geologic-map database should be used to evaluate and understand the geologic character of the Telegraph 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 geologic materials and structures. However, it is not sufficiently detailed for site-specific determinations. 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 parts 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 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, 5.7, sun4u UNIX ARC/INFO version 7.2.1 Group: Distribution Distribution_Media: online Distribution_Format : ArcInfo export (e00) Distribution_Size: 2.9 megabytes Fees: none End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-293/images/tel_map.jpg Format: JPEG Group: Description Non-navigable image of the geologic map, topographic base, Correlation of Map Units, Description of Map Units and key to point and line symbols. 400x406 pixels, 32-bit RGB true color, 54k bytes. End_Group End_Group Group: Multimedia_Sample URL: http://geopubs.wr.usgs.gov/open-file/of01-293/tel_map.pdf Format: PDF Group: Description Navigable portable document file image of the geologic map, topographic base, Correlation of Map Units, Description of Map Units and key to point and line symbols. End_Group End_Group Group: Reference Citation_Information: Originator: D.M. Morton Publication_Date: 1976 Title: Geologic map of the Cucamonga fault zone between San Antonio Canyon and Cajon Creek, southern California Edition: Version 1.0 Geospatial_Data_Presentation_Form: paper map Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 76-726 Publication_Information: Publication_Place: Menlo Park, California Publisher: U.S. Geological Survey End_Group Group: Summary The data set for the Telegraph 7.5' quadrangle was prepared under the U.S. Geological Survey Southern California Areal Mapping Project (SCAMP) and the California Division of Mines as part of an ongoing effort to develop a regional geologic framework of southern California, and to utilize a Geographical 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. The digital geologic map database for the Telegraph 7.5' quadrangle has been created as a general-purpose data set that is applicable to other land-related investigations in the earth and biological sciences. For example, the U.S. Forest Service, San Bernardino National Forest, may use the map and database as a basic geologic data source for soil studies, mineral resource evaluations, road building, biological surveys, and general forest management. The database is not suitable for site-specific geologic evaluations at scales greater than 1:24,000 (1 in = 2,000 ft). This data set maps and describes the geology of the Telegraph 7.5' quadrangle, San Bernardino County, California. Created using Environmental Systems Research Institute's ARC/INFO software, the data base consists of the following items: (1) a double precision map coverage containing geologic contacts and units, (2) a coverage containing site-specific structural data, (3) a coverage containing geologic-unit label leaders and their associated 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), an index map, a regional geologic and structure map, and a key for point and line symbols; (2) PDF files of this Readme (including the metadata file as an appendix), Description of Map Units (DMU), and the graphic produced by the PostScript plot file. The Telegraph Peak quadrangle is located in the eastern San Gabriel Mountains part of the Transverse Ranges Province of southern California. The generally east-striking structural grain characteristic of the crystalline rocks of much of the San Gabriel Mountains is apparent, but not well developed in the Telegraph Peak quadrangle. Here, the east-striking structural grain is somewhat masked by the northwest-striking grain associated with the San Andreas Fault zone. Faults within the quadrangle include northwest-striking, right-lateral strike-slip faults of the San Andreas system. The active San Andreas Fault, located in the northern part of the quadrangle, dominates the younger structural elements. North of the San Andreas Fault is the inactive Cajon Valley Fault that was probably an early strand of the San Andreas system. It was active during deposition of the middle Miocene Cajon Valley Formation. South of the San Andreas, the Punchbowl Fault, which is probably a long-abandoned segment of the San Andreas Fault (Matti and Morton, 1993), has a sinuous trace apparently due to compression in the eastern San Gabriel Mountains that post-dates displacement on the fault. The Punchbowl Fault separates two major subdivisions of the Mesozoic Pelona Schist and is left-laterally offset by a northeast-striking fault in the northwestern part of the quadrangle. Within the Punchbowl Fault zone is a thin layer of highly deformed basement rock, which is clearly not part of the Pelona Schist. To the southeast, in the Devore quadrangle, this included basement rock attains a thickness of several hundred feet. Along strike to the northwest, Tertiary sedimentary rocks are included within the fault zone. South of the Punchbowl Fault are several arcuate (in plan) faults that are part of an antiformal schuppen-like fault complex of the eastern San Gabriel Mountains. Most of these arcuate faults are reactivated and deformed older faults, and probably include the eastern part of the San Gabriel Fault. The Vincent Thrust of late Cretaceous or early Tertiary age separates the Pelona Schist in the lower plate from a heterogeneous basement complex in the upper plate. Immediately above the Vincent Thrust is a variable thickness of mylonitic rock generally interpreted as a product of displacement on the thrust. The upper plate includes two Paleozoic units, a schist and gneiss sequence and a schist, quartzite, and marble metasedimentary sequence. Both sequences are thrust over the Mesozoic Pelona Schist along the Vincent Thrust, and intruded by Tertiary (late Oligocene) granitic rocks, granodiorite of Telegraph Peak, that also intrude the Vincent Thrust. The Pelona Schist consists mostly of greenschist to amphibolite metamorphic grade meta-basalt (greenschist and amphibolite) and meta-graywacke (siliceous and white mica schist), with minor impure quartzite and marble, in which all primary structures have been destroyed and all layering transposed. Cretaceous granitic rocks, chiefly tonalite, intrude the schist and gneiss sequence, but not the Pelona Schist or the Vincent Thrust. North of the San Andreas Fault, bedrock units consist of undifferentiated Cretaceous tonalite, here informally named tonalite of Circle Mountain, with some included small boldies of gneiss and marble. These basement rocks are the westward continuation of rocks of the San Bernardino Mountains and not rocks of the San Gabriel Mountains south of the San Andreas Fault. Also north of the San Andreas Fault are the Oligocene Vaqueros Formation, middle Miocene Cajon Valley Formation, and Pliocene rocks of Phelan Peak. The latter two formations are divided into several conglomerate and arkosic sandstone subunits. In the northeastern corner of the quadrangle, the rocks of Phelan Peak are unconformably overlain by the Quaternary Harold Formation and Shoemaker Gravel. Quaternary units ranging from early Pleistocene to recent are mapped, and represent alluvial fan, landslide, talus, and wash environments. The geologic map database contains original U.S. Geological Survey data generated by detailed field observation and by interpretation of aerial photographs. This digital Open-File map supercedes an older analog Open-File map of the quadrangle, and includes extensive new data on the Quaternary deposits, and revises some fault and bedrock distribution within the San Gabriel Mountains. The digital map was compiled on a base-stable cronoflex copy of the Telegraph 7.5' topographic base and then scribed. This scribe guide was used to make a 0.007 mil blackline clear-film, from which lines and point were hand digitized. Lines, points, and polygons were subsequently edited at the USGS 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 as 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: 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: 20010917 Science_Review_Date: