Citation:
Citation_Information:
Originator: Robert E. Powell
Originator: Pamela M. Cossette (digital cartography)
Publication_Date: 2001
Title:
Geologic map and digital database of the Conejo Well 7.5
minute quadrangle, Riverside County, California
Edition: Version 1.0
Geospatial_Data_Presentation_Form: Vector digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 01-31
Publication_Information:
Publication_Place: Menlo Park, California
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/of/2001/of01-031/
Description:
Abstract:
This data set maps and describes the geology of the Conejo
Well 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 part of
the northern Eagle Mountains and part of the 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 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 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 in
the Eagle Mountains and an east-west trending system of
high-angle dip- and left-slip faults. In and adjacent to
the Conejo Well quadrangle, faults of the
northwest-trending set displace Miocene sedimentary rocks
and basalt deposited on the Tertiary erosion surface and
Pliocene and (or) Pleistocene deposits that accumulated on
the oldest pediment. Faults of this system appear to be
overlain by Pleistocene deposits that accumulated on
younger pediments. East-west trending faults are younger
than and perhaps in part coeval with faults of the
northwest-trending set.
The Conejo Well 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 point coverage containing line ornamentation, and (5) a
scanned topographic base at a scale of 1:24,000. The coverages
include 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.
Purpose:
The data set for the Conejo Well 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
Conejo Well 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 Conejo Well 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 Conejo Well
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
Conejo Well 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.
Supplemental_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?, Jmi?)
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. In
some polygons, multiple units crop out in individual domains
that are too small or too intricately intermingled to
distinguish at 1:24,000, or for which relations are not well
documented. For these polygons, unit symbols are combined
using plus (+) signs (e.g., Qyaos + Qyas2) in the LABL and
PLABL items.
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.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 1973
Ending_Date: 2000
Currentness_Reference: New data
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As Needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -115.75009096
East_Bounding_Coordinate: -115.62490904
North_Bounding_Coordinate: 33.87499995
South_Bounding_Coordinate: 33.7499842
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: geology
Theme_Keyword: geologic maps
Theme_Keyword: surficial geologic units
Theme_Keyword: bedrock geologic units
Theme_Keyword: geologic structure
Theme_Keyword: geospatial datasets
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: fault
Theme_Keyword: erosion surface
Theme_Keyword: pediment
Theme_Keyword: soil
Theme_Keyword: alluvial deposits
Theme_Keyword: dike
Theme_Keyword: batholith
Theme_Keyword: metamorphic rocks
Theme_Keyword: plutonic rocks
Theme_Keyword: hypabyssal rocks
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Categories
Theme_Keyword: geoscientificInformation
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: southern California
Place_Keyword: Riverside County
Place_Keyword: Joshua Tree National Park
Place_Keyword: eastern Transverse Ranges
Place_Keyword: Eagle Mountains
Place_Keyword: Pinto Basin
Place_Keyword: Conejo Well 7.5 minute quadrangle
Place_Keyword: Pinto Basin 15 minute quadrangle
Place_Keyword: Eagle Mountains 30 x 60 minute quadrangle
Stratum:
Stratum_Keyword_Thesaurus: None
Stratum_Keyword: Granite gneiss of Joshua Tree
Stratum_Keyword: Pinto Gneiss
Stratum_Keyword: Augen gneiss of Monument Mountain
Stratum_Keyword: Granodiorite of Pinto Basin
Stratum_Keyword: Monzogranite of Cottonwood Pass
Stratum_Keyword: Monzogranite of Red Butte Wash
Stratum_Keyword: Monzodiorite of Munsen Canyon
Stratum_Keyword: Quartzite of Pinto Mountain
Stratum_Keyword: Dolomite of Iron Chief mine
Stratum_Keyword: Basalt
Stratum_Keyword: Alluvium
Place:
Place_Keyword_Thesaurus: Augmented FIPS 10-4 and FIPS 6-4
Place_Keyword: f06065 = Riverside
Access_Constraints: None
Use_Constraints:
Spatial Resolution. Use of this digital geologic map should
not violate the spatial resolution of the data. The Conejo
Well 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 Conejo Well 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 Conejo Well 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 Conejo Well 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.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Robert E. Powell
Contact_Organization:
U.S.Geological Survey, Western Region, Earth Surface Processes Team
Contact_Position: Project geologist
Contact_Address:
Address_Type: mailing address
Address:
U.S. Geological Survey
Room 202
West 904 Riverside Avenue
City: Spokane
State_or_Province: Washington
Postal_Code: 99201-1087
Country: USA
Contact_Voice_Telephone: (509) 368-3120
Contact_Facsimile_Telephone: (509) 368-3199
Contact_Electronic_Mail_Address: rpowell@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-031/images/cwell.gif
Browse_Graphic_File_Description:
Non-navigable 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. 375x593 pixels, 64kb.
Browse_Graphic_File_Type: GIF
Browse_Graphic:
Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-031/cwell_map.pdf
Browse_Graphic_File_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. (4.9 MB)
Browse_Graphic_File_Type: PDF
Data_Set_Credit:
Geologic mapping, topical studies, and digital preparation
for this report were sponsored jointly by the following: (1)
the National Cooperative Geologic Mapping Program of the
U.S. Geological Survey, (2) California Division of Mines
and Geology, and (3) the National Park Service (Joshua Tree
National Park).
This database was prepared in the GIS laboratory at the
Spokane Field Office of the USGS in Spokane, Washington. The
facility is maintained primarily by the Mineral Resource
Surveys Program and supported in part by the National
Geologic Mapping Program. We thank Paul C. Hyndman and
Steven R. Munts in Spokane and Rachel Hauser Alvarez of the
SCAMP GIS laboratory at the University of California,
Riverside for their assistance in solving problems
encountered during digital preparation of the data set.
Technical review by Fred K. Miller has led to significant
improvements in the database and in the map plot file.
David R. Bedford has examined the digital database file for
internal logical consistency, has reviewed the metadata
file, and has tested the viability of digital products.
Native_Data_Set_Environment:
SunOS, 5.6, sun4u UNIX
ARC/INFO version 7.2.1
Cross_Reference:
Citation_Information:
Originator: Robert E. Powell
Publication_Date: 2001
Title:
Geologic map and digital database of the Porcupine Wash 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: 01-30
Publication_Information:
Publication_Place: Menlo park, California
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/of/2001/0030/
