Digital geologic map of the Thirsty Canyon NW quadrangle, Nye County, Nevada

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

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