Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Originator: Scott A. Minor Publication_Date: 19981105 Title: Digital geologic map of the Thirsty Canyon NW quadrangle, Nye County, Nevada Edition: Version 1.0 Geospatial_Data_Presentation_Form: map vector digital data Series_Information: Series_Name: Open-File Report Issue_Identification: 98-623 Publication_Information: Publication_Place: Denver, Colorado Publisher: U.S. Geological Survey Online_Linkage: http://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-98-0623/ Description: Abstract: This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern Nevada. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic and tectonic interest. The Thirsty Canyon NW quadrangle is located in southern Nye County about 20 km west of the Nevada Test Site (NTS) and 30 km north of the town of Beatty. The map area is underlain by extensive layers of Neogene (about 14 to 4.5 million years old [Ma]) mafic and silicic volcanic rocks that are temporally and spatially associated with transtensional tectonic deformation. Mapped volcanic features include part of a late Miocene (about 9.2 Ma) collapse caldera, a Pliocene (about 4.5 Ma) shield volcano, and two Pleistocene (about 0.3 Ma) cinder cones. Also documented are numerous normal, oblique-slip, and strike-slip faults that reflect regional transtensional deformation along the southern part of the Walker Lane belt. The Thirsty Canyon NW map provides new geologic information for modeling groundwater flow paths that may enter the map area from underground nuclear testing areas located in the NTS about 25 km to the east. The geologic map database comprises six component ArcINFO map coverages that can be accessed after decompressing and unbundling the data archive file (tcnw.tar.gz). These six coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt) are formatted here in ArcINFO EXPORT format. Bundled with this database are two PDF files for readily viewing and printing the map, accessory graphics, and a description of map units and compilation methods. Purpose: To provide a digital geologic map database of the quadrangle that improves understanding of the regional geologic framework and its influence on the regional groundwater flow system. Supplemental_Information: The current map database incorporates geologic data from: (1) early geologic mapping (1965-1969) by P.P. Orkild and K.A. Sargent of chiefly flat-lying volcanic rocks in the eastern part of the mapped area; (2) more recent field mapping (1991-1995) by S.A. Minor of older, more deformed bedrock terrane (i.e., pre-~12-Ma rocks) in the western part of the mapped area; (3) recent (1994) mapping by S.A. Minor and D.A. Sawyer of part of the Thirsty Mountain shield volcano in the southern part of the mapped area; (4) recent mapping (at 1:100,000-scale detail) of surficial deposits mainly in the southwestern part of the mapped area (Wahl and others, 1997); and (5) new detailed petrographic and geochemical data of Tertiary volcanic units of the southwest Nevada volcanic field obtained by R.G. Warren and D.A. Sawyer (written commun., 1998). Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 19981105 Currentness_Reference: Publication date Status: Progress: Complete Maintenance_and_Update_Frequency: As Needed. Mapping is continuing in adjacent quadrangles and a more complete final map of this area may eventually be produced. Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -116.75 East_Bounding_Coordinate: -116.625 North_Bounding_Coordinate: 37.25 South_Bounding_Coordinate: 37.125 Keywords: Theme: Theme_Keyword_Thesaurus: AGI Glossary of Geology, 1977 Theme_Keyword: digital-geologic-map Theme_Keyword: Quaternary-surficial-deposits Theme_Keyword: Tertiary-volcanic-rocks Theme_Keyword: Quaternary-basaltic-cinder-cones Theme_Keyword: transtensional-faults Theme_Keyword: Black-Mountain-caldera Place: Place_Keyword_Thesaurus: none Place_Keyword: USA Place_Keyword: Nevada Place_Keyword: Nye County Place_Keyword: Nellis Air Force Range Place_Keyword: Thirsty Mountain Access_Constraints: none Use_Constraints: none--Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. These data are not to be used at scales larger than 1:24,000. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Scott A. Minor Contact_Organization: U.S. Geological Survey, Geologic Division, National Cooperative Geologic Mapping Team Contact_Position: research geologist Contact_Address: Address_Type: mailing and physical address Address: Box 25046, MS 913 City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 303-236-0303 Contact_Facsimile_Telephone: 303-236-0214 Contact_Electronic_Mail_Address: sminor@usgs.gov Data_Set_Credit: Funding for map project was provided by the U.S. Department of Energy. Permission for field access was granted by, and a field escort was provided by, the Nellis Air Force Range. T.R. Brandt and J.B. Workman assisted in compiling the digital database and in preparing the digital cartographic output. Native_Data_Set_Environment: SunOS, 5.6, sun4m UNIX ARC/INFO version 7.1.2 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Original data was entered and checked by the principal geologist/author, who also made a majority of the field observations. Map compilation was subjected to technical review by coauthors and by other USGS geologist. Logical_Consistency_Report: Polygon and chain-node topology present. Map elements were visually checked by the author for overshoots, undershoots, duplicate features, and other errors. Completeness_Report: This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Data is complete: no features were eliminated or generalized. Unit properties are described in the text explanation. A digital base map coverage is not included but is available separately. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Original, scale-stable, geologic map data were scanned at a resolution of 300 dpi (dots per inch). New geologic data mapped on ~1:24,000-scale aerial photos were digitized photogrammetrically with a horizontal positional accuracy of ~10 m (ground meters). Most digitized positions on the final map compilation are estimated to have an horizontal accuracy of 10-20 m. Lineage: Process_Step: Process_Description: Original geologic mapping by P.P. Orkild and K.A. Sargent of chiefly flat-lying volcanic rocks in the eastern part of the mapped area. Process_Date: 19691231 Process_Step: Process_Description: Hand-drafted stable-base layers of the early, original mapping were scanned and vectorized and then edited using AutoCAD software. Process_Date: 19911003 Process_Step: Process_Description: Recent mapping by S.A. Minor and D.A. Sawyer of part of the Thirsty Mountain shield volcano in the southern part of the mapped area. Process_Date: 19941231 Process_Step: Process_Description: Recent field mapping by S.A. Minor of older, more deformed bedrock terrane (i.e., pre-~12-Ma rocks) in the western part of the mapped area. Process_Date: 19951231 Process_Step: Process_Description: Recent mapping (at 1:100,000-scale detail) of surficial deposits mainly in the southwestern part of the mapped area. Process_Date: 19961231 Process_Step: Process_Description: New geologic field data, which were mapped on aerial photographs of about 1:24,000 scale, were mainly digitized directly from the photographs using a Kern PG-2 stereographic plotter interfaced with CADMAP digital capturing software. The new map data were also imported into AutoCAD for editing. Process_Date: 19961231 Process_Step: Process_Description: Geographic Resource Analysis Support System (GRASS), a public-domain GIS, was used to transform the component map files to Universal Transverse Mercator (UTM) projection and coordinate system. The various map data layers were then converted to ArcINFO coverages. Process_Date: 19970819 Process_Step: Process_Description: ArcINFO was used to conduct final editing and modification of map elements, build and tag polygons, assign attributes to map elements, and generate a plot file of the final geologic compilation. Process_Date: 19980710 Process_Step: Process_Description: First draft of metadata created by sminor using FGDCMETA.AML ver. 1.2 05/14/98 on ARC/INFO data set /data_2/data/sminor/tcnw/tcnwpoly Process_Date: 19990901 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 614 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 2008 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 613 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 576 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 15 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 34 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 11 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 187 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 11 Transverse_Mercator: Scale_Factor_at_Central_Meridian: .9996 Longitude_of_Central_Meridian: -117 Latitude_of_Projection_Origin: 0 False_Easting: 500000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 1.390341 Ordinate_Resolution: 1.390341 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: NAS_B Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The geologic map database comprises six component ArcINFO map coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt). The tcnwpoly coverage contains all contact lines and labelpoints for each of the map polygons. The database includes four line coverages that depict faults (tcnwflt), fold axes (tcnwfold), dikes (tcnwdike), and caldera-wall segments (tcnwcald). Faults that are contacts also appear in the tcnwpo Entity_and_Attribute_Detail_Citation: Listed below are definitions of alpha and numeric attribute codes that are embedded in the various INFO files (i.e., TCNW*.PAT and TCNW*.AAT files) associated with the geologic Arc coverages. The name of the INFO file containing the listed attribute codes is present above each list, and those column headings in each list with capitalized letters correspond to custom ITEMS in the INFO files that contain the listed codes. >TCNWPOLY.PAT: >(Numeric codes associated with the item COLOR in the TCNWPOLY.PAT file refer to map-unit polygon colors defined in the Arc shadeset file color524.shd.) > >UNIT# LABEL Definition >1 Qay Young alluvium (Holocene and late Pleistocene) >2 QTc Colluvium (Quaternary and Pliocene) >3 Qam Middle alluvium (middle Pleistocene) > Basalt of Little Black Peak (middle Pleistocene) >4 Qbbc Cinder cone >5 Qbbl Lava flow > Basalt of Hidden Cone (middle Pleistocene) >6 Qbhc Cinder cone >7 Qbhl3 Upper lava flow >8 Qbhl2 Middle lava flow >9 Qbhl1 Lower lava flow >10 QTa Old alluvium (early Pleistocene and Pliocene?) >11 Typ Basalt of Thirsty Mountain (Pliocene) >12 Typv Vent-facies scoria deposits >13 Tgo Gravel of Oasis Valley (Pliocene and Miocene) >14 Ttb Thirsty Canyon and younger basalts (Miocene) > Thirsty Canyon Group (Miocene) >15 Ttg Gold Flat Tuff >16 Tts Trachytic lavas of Pillar Spring >17 Ttf Black Mountain caldera moat-filling sediments >18 Ttt Trail Ridge Tuff >19 Ttp Pahute Mesa Tuff >20 Ttr Rocket Wash Tuff >21 Ttc Comendite of Ribbon Cliff >22 Tte Pre-Thirsty Canyon basaltic rocks (Miocene) >23 Tbd Basalt dikes (Miocene) >24 Tfu Tuff and tuffaceous sedimentary rocks, undivided (Miocene) >25 Txmr Gravity-slide breccia of Rainier Mesa Tuff (Miocene) > Timber Mountain Group (Miocene) >26 Tma Ammonia Tanks Tuff >27 Tmt Basalts in Timber Mountain Group >28 Tmr Rainier Mesa Tuff > Paintbrush Group (Miocene) >29 Tpc Tiva Canyon Tuff >30 Txbg Gravity-slide breccia of Grouse Canyon Tuff (Miocene) > Belted Range Group (Miocene) >31 Tbg Grouse Canyon Tuff >32 Tbgb Bedded Grouse Canyon Tuff >33 Tob Older basalt (Miocene) > Volcanic rocks of Quartz Mountain (Miocene) >34 Tqg Crystal-poor rhyolite lava >36 Txqs Gravity-slide breccia of tuff of Sleeping Butte >37 Txqh Gravity-slide breccia of hornblende rhyolite lava > Tuff of Sleeping Butte >38 Tqsu Upper nonwelded tuff > Lower welded tuff >39 Tqsp Upper partly welded facies >40 Tqsm Middle welded facies >41 Tqsl Lower crystal-poor welded facies >42 Tqp Pyroxene rhyolite lava >43 Tqpb Pyroxene rhyolite pyroclastic rocks >44 Tqh Hornblende rhyolite lava >45 Tqhb Hornblende rhyolite pyroclastic rocks >46 Tqht Partly welded tuff >47 Tqt? Tuff of Tolicha Peak? >48 Tqhs Sedimentary rocks >49 Typd Feeder dikes (Basalt of Thirsty Mountain) (Pliocene) > > >TCNWFLT.AAT: > >FAULT_SLIP Definition >und fault slip not determined >Lbb normal fault; down-to-left (with respect to origin of digital fault line) apparent offset >Rbb normal fault; down-to-right apparent offset >Rss strike-slip fault; right-lateral sense of movement >Lss strike-slip fault; left-lateral sense of movement >Lro oblique-slip fault; down-to-left / right-lateral sense of movement >Llo oblique-slip fault; down-to-left / left-lateral sense of movement >Rro oblique-slip fault; down-to-right / right-lateral sense of movement >Rlo oblique-slip fault; down-to-right / left-lateral sense of movement >vent concealed linear vent of basalt of Thristy Mountain inferred from geophysical data > >FAULT_TRACE Definition >well well located fault >inf approximately located/inferred fault >con concealed fault >geophys concealed structure; location constrained by geophysical expression > > >TCNWATTS.PAT: >(Each record in TCNW.PAT includes a strike AZIMUTH and a DIP value, where the strike azimuth is measured clockwise with respect to north and the dip direction is 90o clockwise relative to the azimuth (i.e., "right hand rule"). In the case of fault plane measurements, TREND and PLUNGE indicate the orientation of slickenside striations or lineations.) > >TYPE Definition >BED inclined bedding >FOL compaction or flow foliation >FLT fault plane >MES mesoscale fault plane Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, National Cooperative Geologic Mapping Team Contact_Position: research geologist Contact_Address: Address_Type: mailing address Address: Scott A. Minor Address: U.S. Geological Survey Address: MS 913, Box 25046 DFC City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 303-236-0303 Contact_Voice_Telephone: 303-236-7880 Contact_Instructions: Contact via email Contact_Electronic_Mail_Address: sminor@usgs.gov Distribution_Liability: Although this digital spatial data has been subjected to rigorous review and is substantially complete, it is released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ARCE Format_Version_Number: 7.12 Format_Version_Date: 1997 File_Decompression_Technique: GZIP self-extracting archive, Unix or Windows versions Transfer_Size: Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://greenwood.cr.usgs.gov/pub/open-file-reports/ofr-98-0623/ Fees: none Metadata_Reference_Information: Metadata_Date: 19990901 Metadata_Review_Date: 19990915 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, National Cooperative Geologic Mapping Team Contact_Person: Scott A. Minor Contact_Position: research geologist Contact_Address: Address_Type: mailing address Address: MS 913, Box 25046 DFC City: Denver State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 303-236-0303 Contact_Facsimile_Telephone: 303-236-0214 Contact_Electronic_Mail_Address: sminor@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Access_Constraints: none Metadata_Use_Constraints: none