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Powell, Robert E. , and Pamela M. Cossette (digital cartography), 2001, Geologic map and digital database of the Porcupine Wash 7.5 minute quadrangle, Riverside County, California: U.S. Geological Survey Open-File Report USGS OF 01-30, U.S. Geological Survey, Menlo Park, California.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
The map projection used is Polyconic.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.000001
Ordinates (y-coordinates) are specified to the nearest 0.000001
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.
Value | Definition |
---|---|
Qa | Very young alluvial deposits (late Holocene) |
Qa2 | Very young alluvial deposits, Unit 2 (late Holocene) |
Qa1 | Very young alluvial deposits, Unit 1 (late Holocene) |
Qyai3 | Young alluvial deposits, insensitive source, Unit 3 (late and (or) middle Holocene) |
Qyai2 | Young alluvial deposits, insensitive source, Unit 2 (middle Holocene) |
Qyai1 | Young alluvial deposits, insensitive source, Unit 1 (middle and (or) early Holocene and (or) latest Pleistocene?) |
Qyas2,3 | Young alluvial deposits, sensitive source, Units 2 and 3 (late and (or) middle Holocene) |
Qyas3 | Young alluvial deposits, sensitive source, Unit 3 (late and (or) middle Holocene) |
Qyas2 | Young alluvial deposits, sensitive source, Unit 2 (late and (or) middle Holocene) |
Qyas2? | Young alluvial deposits, sensitive source, Unit 2? (late and (or) middle Holocene) |
Qyaos | Young alluvial deposits, oxidized, sensitive source (Holocene and latest Pleistocene?) |
Qoai3 | Old alluvial deposits, insensitive source, Unit 3 (late Pleistocene) |
Qoai2 | Old alluvial deposits, insensitive source, Unit 2 (middle? Pleistocene) |
Qoaps | Old alluvial deposits, pavemented, sensitive source (late Pleistocene) |
Qoaos | Old alluvial deposits, oxidized, sensitive source (middle? Pleistocene) |
Qoaos? | Old alluvial deposits, oxidized, sensitive source? (middle? Pleistocene) |
Qoars | Old alluvial and (or) regolithic deposits, sensitive source (middle? Pleistocene) |
Qoc | Old colluvial deposits (Pleistocene) |
Qoc1,2 | Old colluvial deposits, Units 1 and 2 (Pleistocene) |
Qovork | Old and (or) very old regolithic deposits, cemented (middle? and (or) early? Pleistocene) |
Qvoa | Very old alluvial deposits (middle and early Pleistocene) |
QTs? | Sedimentary deposits? (Quaternary and (or) Tertiary) |
QTrcp | Regolith, monzogranite of Cottonwood Pass (Quaternary and Tertiary) |
QTrcp? | Regolith, monzogranite of Cottonwood Pass? (Quaternary and Tertiary) |
QTrpb | Regolith, granodiorite of Pinto Basin (Quaternary and Tertiary) |
QTrpb? | Regolith, granodiorite of Pinto Basin? (Quaternary and Tertiary) |
QTrp | Regolith, Pinto Gneiss (Quaternary and Tertiary) |
Trscp | Saprolite, monzogranite of Cottonwood Pass (Tertiary) |
Trscp? | Saprolite, monzogranite of Cottonwood Pass? (Tertiary) |
KJmgccp | Monzogranite of Cottonwood Pass (Cretaceous or Jurassic) |
KJmgccp? | Monzogranite of Cottonwood Pass? (Cretaceous or Jurassic) |
Kgdpb | Granodiorite of Pinto Basin (Cretaceous) |
Kgdpb? | Granodiorite of Pinto Basin? (Cretaceous) |
TrPmc | Monzodiorite of Munsen Canyon (Triassic or Permian) |
Prmag | Augen gneiss of Monument Mountain (Middle Proterozoic) |
Prpg | Pinto Gneiss of Miller, 1938 (Proterozoic) |
Prpgd | Pinto Gneiss, dark (Proterozoic) |
Prpgd? | Pinto Gneiss, dark? (Proterozoic) |
Prpgl | Pinto Gneiss, leucocratic granitic orthogneiss (Middle Proterozoic) |
Prpgl? | Pinto Gneiss, leucocratic granitic orthogneiss? (Middle Proterozoic) |
Prppw | Siliceous granofels of Wilson Canyon (Proterozoic) |
TKq? | Quartz? (Tertiary or Cretaceous) |
TJh? | Hypabyssal intrusive rocks? (Tertiary or Jurassic) |
Value | Definition |
---|---|
Prhgc | Gneiss complex of Hexie Mountains (Proterozoic) |
Prmag | Augen gneiss of Monument Mountain (Middle Proterozoic) |
Prmg | Porphyritic granodiorite, monzogranite, and augen gneiss of Monument Mountain (Middle Proterozoic) |
Prpg | Pinto Gneiss of Miller, 1938 (Proterozoic) |
Prpgd | Pinto Gneiss, dark (Proterozoic) |
Prpgl | Pinto Gneiss, leucocratic granitic orthogneiss (Middle Proterozoic) |
Prpp | Metsedimentary and (or) metamorphosed hydrothermally altered rocks of Pinkham Canyon (Proterozoic) |
Prppw | Siliceous granofels of Wilson Canyon (Proterozoic) |
Value | Definition |
---|---|
Qovork | Old and (or) very old regolithic deposits, cemented (middle? and (or) early? Pleistocene) |
QTr | Regolith (Quaternary and Tertiary) |
QTrmgc | Regolith, coarse-grained monzogranite (Quaternary and Tertiary) |
QTrcp | Regolith, monzogranite of Cottonwood Pass (Quaternary and Tertiary) |
QTrgd | Regolith, granodiorite (Quaternary and Tertiary) |
QTrpb | Regolith, granodiorite of Pinto Basin (Quaternary and Tertiary) |
QTrp | Regolith, Pinto Gneiss (Quaternary and Tertiary) |
Tr | Regolith (Tertiary) |
Trs | Saprolite (Tertiary) |
Trscp | Saprolite, monzogranite of Cottonwood Pass (Tertiary) |
Value | Definition |
---|---|
KJmgc | Monzogranite, coarse-grained (Cretaceous and (or) Jurassic) |
KJmgccp | Monzogranite of Cottonwood Pass (Cretaceous or Jurassic) |
Kgd | Granodiorite (Cretaceous) |
Kgdpb | Granodiorite of Pinto Basin (Cretaceous) |
TrPmc | Monzodiorite of Munsen Canyon (Triassic or Permian) |
Mzbc | Batholith of Transverse Ranges and Mojave Desert, central belt (Mesozoic) |
Mzb | Batholith of Transverse Ranges and Mojave Desert (Mesozoic) |
Prmag | Augen gneiss of Monument Mountain (Middle Proterozoic) |
Prmg | Porphyritic granodiorite, monzogranite, and augen gneiss of Monument Mountain (Middle Proterozoic) |
Prpgg | Porphyritic granitoids and augen gneiss (Middle Proterozoic) |
Prpgl | Pinto Gneiss, leucocratic granitic orthogneiss (Middle Proterozoic) |
Value | Definition |
---|---|
Qa | Very young alluvial deposits (late Holocene) |
Qa2 | Very young alluvial deposits, Unit 2 (late Holocene) |
Qa1 | Very young alluvial deposits, Unit 1 (late Holocene) |
Qya | Young alluvial deposits (Holocene and latest Pleistocene?) |
Qyai | Young alluvial deposits, insensitive source (Holocene and latest Pleistocene?) |
Qyai3 | Young alluvial deposits, insensitive source, Unit 3 (late and (or) middle Holocene) |
Qyai2 | Young alluvial deposits, insensitive source, Unit 2 (middle Holocene) |
Qyai1 | Young alluvial deposits, insensitive source, Unit 1 (middle and (or) early Holocene and (or) latest Pleistocene?) |
Qyas | Young alluvial deposits, sensitive source (Holocene and latest Pleistocene?) |
Qyas2,3 | Young alluvial deposits, sensitive source, Units 2 and 3 (late and (or) middle Holocene) |
Qyas3 | Young alluvial deposits, sensitive source, Unit 3 (late and (or) middle Holocene) |
Qyas2 | Young alluvial deposits, sensitive source, Unit 2 (late and (or) middle Holocene) |
Qyas2? | Young alluvial deposits, sensitive source, Unit 2? (late and (or) middle Holocene) |
Qyaos | Young alluvial deposits, oxidized, sensitive source (Holocene and latest Pleistocene?) |
Qyua | Very young and young alluvial deposits (Holocene) |
Qoaos? | Old alluvial deposits, oxidized, sensitive source? (middle? Pleistocene) |
Qoa | Old alluvial deposits (Pleistocene) |
Qoai | Old alluvial deposits, insensitive source (Pleistocene) |
Qoai3 | Old alluvial deposits, insensitive source, Unit 3 (late Pleistocene) |
Qoai2 | Old alluvial deposits, insensitive source, Unit 2 (middle? Pleistocene) |
Qoas | Old alluvial deposits, sensitive source (Pleistocene) |
Qoaps | Old alluvial deposits, pavemented, sensitive source (late Pleistocene) |
Qoaos | Old alluvial deposits, oxidized, sensitive source (middle? Pleistocene) |
Qoars | Old alluvial and (or) regolithic deposits, sensitive source (middle? Pleistocene) |
Qoua | Old and very old alluvial deposits, undivided (Pleistocene) |
Qoc | Old colluvial deposits (Pleistocene) |
Qoc1,2 | Old colluvial deposits, Units 1 and 2 (Pleistocene) |
Qovork | Old and (or) very old regolithic deposits, cemented (middle? and (or) early? Pleistocene) |
Qvoa | Very old alluvial deposits (middle and early Pleistocene) |
QTs? | Sedimentary deposits? (Quaternary and (or) Tertiary) |
Value | Definition |
---|---|
TKq? | Quartz? (Tertiary or Cretaceous) |
Value | Definition |
---|---|
TJh? | Hypabyssal intrusive rocks? (Tertiary or Jurassic) |
Value | Definition |
---|---|
Qopb | Old pedogenic B-horizon (middle? Pleistocene) |
Value | Definition |
---|---|
TKdp | Dacite porphyry dike (Tertiary or Cretaceous) |
TJd | Dike (Tertiary, Cretaceous, or Jurassic) |
Kap | Aplite dike (Cretaceous) |
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 Jonathan C. Matti has led to significant improvements in the database and in the map plot file. Todd T. Fitzgibbon has examined the digital database file for internal logical consistency, has reviewed the metadata file, and has tested the viability of digital products.
(509) 368-3120 (voice)
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rpowell@usgs.gov
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.
Powell, Robert E. , 2001, Geologic map and digital database of the Conejo Well 7.5 minute quadrangle, Riverside County, California: U.S. Geological Survey Open-File Report USGS OF 01-31, U.S. Geological Survey, Menlo park, California.Online Links:
This initial version of the Porcupine Wash geologic map database relies extensively on interpretation of aerial photographs; field study of bedrock units was conducted in the context of smaller-scale regional mapping and field study of surficial deposits has been minimal. The map represents the state of knowledge for the quadrangle and provides a basis for gathering additional field data to resolve questions raised in making the map. Attributes assigned to regions, polygons, lines, and points in the Porcupine Wash database are reasonably accurate as determined by the normal range of checks and balances applied in making a geologic map by a combination of hands-on and remote field observation, sampling, and interpretation of aerial photographs. Additional field investigation, however, is required to verify the accuracy of polygon (map unit) attributes and to establish relations among units. Where anomalous descriptive characteristics lead to particular uncertainty of unit assignment of a polygon, a question mark (?) is appended to the unit label. In the Porcupine Wash quadrangle, this device has been used chiefly for unit assignments of unvisited polygons that appear anomalous on aerial photographs.
Geologic lines and points on 1:24,000 scale geologic maps
are judged to meet map-accuracy standards if they are
located to within +/-15 meters, relative to topographic or
cultural features on the base map. Lines and points that
meet (or may not meet) this map-accuracy standard are
identified both in the digital database and on derivative
geologic-map plots. On geologic-map plots, line data that
are judged to meet the map-accuracy standard are denoted
by solid lines; line data that may not meet the
map-accuracy standard are denoted by dashed or dotted
lines.
Contacts between lithologic domains that make up
surficial deposits as mapped on the digital
orthophotograph quarter quadrangles typically are readily
located to within 15 meters, but to make domains that can
be resolved at 1:24,000 contacts are often drawn by
approximating the dominant unit on a percentage basis.
Interspersal of well- and approximately located contacts
is common among the many hundreds of contact segments
present in the Porcupine Wash quadrangle. Given that many
quadrangles are being mapped in a relatively short time
interval, it was deemed too time-consuming to distinguish
well-located and approximately located contacts between
surficial deposits; therefore, all surficial contacts are
represented as approximately located and shown with a
dashed line symbol.
The geologic map and digital database of the Porcupine Wash 7.5 minute quadrangle contain 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.
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.
Are there legal restrictions on access or use of the data?
- 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.
303-202-4700 (voice)
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USGS Open-File Report 01-30
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 any particular purpose. The burden for determining 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 delivery, installation, operation, or support by USGS.
This digital, geologic map database of the Porcupine Wash 7.5'quadrangle, and any derivative maps thereof, is not meant to be used or displayed at any map scale larger than 1:12,000 on the DOQQ base or 1:24,000 on the topograhic base.
Data format: | Geologic polygons, lines, and symbols, and dictionary coverages, with additional text. in format Arc/Info export (version 7.2.1) Size: 5.5 megabytes |
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Network links: |
<http://geopubs.wr.usgs.gov/open-file/of01-030/pwash.tar.gz> |
509-368-3123 (voice)
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pcossette@usgs.gov