Airborne geophysical survey: Mt. McKinley 1° x 3° Quadrangle

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator:
U.S. Department of Energy, U.S. Geological Survey, Department of Interior and the National Geophysical Data Center, NOAA
Publication_Date: 2009
Title: Airborne geophysical survey: Mt. McKinley 1° x 3° Quadrangle
Geospatial_Data_Presentation_Form: tabular digital data
Online_Linkage: Larger_Work_Citation:
Citation_Information:
Originator:
U.S. Geological Survey, Department of the Interior, the National Geophysical Data Center, U.S. Department of Energy
Publication_Date: 2009
Title:
Aeromagnetic and aeroradiometric data for the Conterminous United States and Alaska from the National Uranium Resource Evaluation (NURE) Program of U.S. Department of Energy
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: OFR 2009-1129
Publication_Information:
Publication_Place: Denver, CO
Publisher: U.S. Geological Survey
Description:
Abstract:
Aeromagnetic and aeroradiometric data were collected along flight lines by instruments in an aircraft that recorded magnetic-field and radiometric values and locations. The magnetic data set presents latitude, longitude, altitude, and magnetic-field values. Geologic symbols or codes are also included. The geologic symbols were picked from surficial geologic maps. The radiometric data set presents latitude, longitude, altitude, geologic symbols or codes, apparent Uranium (Bismuth 214), Thorium (Thallium 208), and Potassium (K 40), the element ratios, and ancillary information.
Purpose:
Aeromagnetic surveys are used for geophysical prospecting. Some variations in magnetic measurements are caused by rocks that contain significant amounts of magnetic minerals (magnetite being the most common). These anomalies reflect variations in the amount and type of magnetic material and the shape and depth of the body of rock. Aeromagnetic anomaly maps are important tools in mapping surficial and buried igneous rocks. The features and patterns of aeromagnetic anomalies can also be used to delineate details of subsurface geology including the locations of buried faults and the thickness of surficial sedimentary rocks. Aeroradiometric surveys measure the radiation emanating from the earth's surface, which provides general estimates of the geographic distribution of uranium, thorium, and potassium in surficial and some bedrock units. Bismuth 214 and Thallium 208 are decay products of Uranium and Thorium. Along with Potassium 40 they give identifiable peaks in the gamma-ray spectra of naturally occurring radiation. The element data and the ratios of the element data are used to help map surficial geology and to detect concentrations of radioactive minerals.
Supplemental_Information:
The U.S. Department of Energy through Bendix Corp. contracted numerous airborne surveys over a period from 1974 to 1981 covering most of the conterminous United States and much of Alaska. The primary purpose was to obtain airborne radiometric data in order to locate and evaluate uranium resources. Aeromagnetic data were also acquired at the same time. In the mid-1980's, all the NURE Program's data were given to the U.S. Geological Survey. The aeromagnetic data were also archived at the National Geophysical Data Center. With the improvement in digital communication and the ability to store and transmit large data sets, the USGS is now able to release the flight-line data in a common format. The U.S. Geological Survey has contracted or flown numerous airborne surveys over a long period (1950's to present). Much of the digital flight-line data have been released to the public through a companion DVD and a web site. Reference is in the Cross-Reference section of this metadata file. A companion CD-ROM/web site has been released containing magnetic data that were generated by digitizing analog maps. The original analog flight-line profiles used to create the analog maps are unavailable. Reference is in the Cross-Reference section of this metadata file. CD's have been released containing the original radiometric flight-line data in various formats. Reference is in the Cross-Reference section of this metadata file.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 19770730
Ending_Date: 19770812
Currentness_Reference:
Time period indicates dates of airborne survey data collection. Time period is expressed in the format YYYYMM or YYYYMMDD when further accuracy is available.
Status:
Progress: complete
Maintenance_and_Update_Frequency: none planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -153.00
East_Bounding_Coordinate: -150.00
North_Bounding_Coordinate: 64.00
South_Bounding_Coordinate: 63.00
Data_Set_G-Polygon:
Data_Set_G-Polygon_Outer_G-Ring:
G-Ring:
-153.00 63.00, -153.00 64.00, -150.00 64.00, -150.00 63.00, -153.00 63.00
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: geophysical surveys
Theme_Keyword: aeromagnetic data
Theme_Keyword: airborne surveys
Theme_Keyword: magnetic surveys
Theme_Keyword: residual magnetic field
Theme_Keyword: total field
Theme_Keyword: magnetic
Theme_Keyword: aeroradiometric surveys
Theme_Keyword: radiometric surveys
Theme_Keyword: radiometric
Theme_Keyword: radioactivity
Theme_Keyword: uranium
Theme_Keyword: thorium
Theme_Keyword: potassium
Theme_Keyword: total count
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: geophysics
Theme_Keyword: geospatial datasets
Theme_Keyword: magnetic field (earth)
Theme_Keyword: aeromagnetic surveying
Theme_Keyword: field monitoring stations
Theme_Keyword: aeroradiometric surveying
Theme_Keyword: radioactivity
Theme_Keyword: uranium
Theme_Keyword: thorium
Theme_Keyword: potassium
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: United States
Place_Keyword: Alaska
Place_Keyword: AK
Place_Keyword: Mt. McKinley
Place_Keyword: Mount McKinley
Place:
Place_Keyword_Thesaurus: Common Geographic Areas
Place_Keyword: f02068 = Denali
Place_Keyword: f02170 = Matanuska-Susitna
Place_Keyword: f02290 = Yukon-Koyukuk
Access_Constraints: none
Use_Constraints:
none. Acknowledgement of the U.S. Geological Survey, National Geophysical Data Center, and U.S. Department of Energy would be appreciated in products derived from these data.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USGS Gravity and Magnetics Contact
Contact_Address:
Address_Type: mailing address
Address:
U.S. Geological Survey
Box 25046 Mail Stop 964
Denver Federal Center
City: Denver
State_or_Province: CO
Postal_Code: 80225
Contact_Voice_Telephone: 303-236-5652
Browse_Graphic:
Browse_Graphic_File_Name: Browse_Graphic_File_Description:
Reduced-size image depicting the data, 844 x 694 pixels, 175,837 bytes
Browse_Graphic_File_Type: JPEG
Data_Set_Credit:
These USGS employees contributed to reformatting and archiving these data: Pat Hill, Bob Kucks, Rick Saltus, Ron Sweeney, Sarah Shearer Cooperating contributors from the National Geophysical Data Center are: Ronald Buhmann, David Dater, Susan McLean, Stewart Racey
Native_Data_Set_Environment:
These data were originally recorded on 9-track magnetic tapes and were transferred to CD-ROM. Data processing took place on a Dell personal computer running a Windows XP operating system. Data were reformatted using the Geosoft, Inc., program Oasis Montaj version 6.3.
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1999
Title:
Digitized Aeromagnetic Datasets of the Conterminous United States, Hawaii, and Puerto Rico
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: OFR 99-557
Publication_Information:
Publication_Place: Denver CO
Publisher: U.S. Geological Survey
Other_Citation_Details:
CD-ROM or online files Complements this publication with analog data
Online_Linkage: <URL:http://pubs.usgs.gov/of/1999/ofr-99-0557/html/mag_home.htm
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2002
Title:
Digital Aeromagnetic Datasets of the Conterminous United States and Hawaii
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: OFR 02-361
Publication_Information:
Publication_Place: Denver CO
Publisher: U.S. Geological Survey
Other_Citation_Details:
CD-ROM or online files Complements this publication with digital data
Online_Linkage: <URL:http://pubs.usgs.gov/of/2002/ofr-02-361/mag_home.htm
Cross_Reference:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 1999
Title:
Aerial Gamma-Ray Surveys of the Conterminous United States and Alaska
Geospatial_Data_Presentation_Form: raster digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: OFR 99-0562-A through -M
Publication_Information:
Publication_Place: Denver CO
Publisher: U.S. Geological Survey
Other_Citation_Details: Thirteen CD-ROMs
Cross_Reference:
Citation_Information:
Originator: U.S. Department of Energy (DOE) Grand Junction Office
Publication_Date: 1978
Title:
Aerial radiometric and magnetic reconnaissance survey of the Eagle-Dillingham area, Alaska
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Grand Junction Bendix Office Report (GJBX)
Issue_Identification: GJBX-113(78)
Publication_Information:
Publication_Place: Grand Junction, Colorado
Publisher: DOE Grand Junction Office
Other_Citation_Details:
map scale 1:500,000 Author(s): Texas Instruments, Inc.
Cross_Reference:
Citation_Information:
Originator: U.S. Department of Energy (DOE) Grand Junction Office
Publication_Date: 1981
Title:
Mt. McKinley Quadrangle, residual intensity magnetic anomaly profile and contour maps
Geospatial_Data_Presentation_Form: map
Series_Information:
Series_Name: Grand Junction Map Open-file Report
Issue_Identification: GJM-002
Publication_Information:
Publication_Place: Grand Junction, Colorado
Publisher: DOE Grand Junction Office
Other_Citation_Details:
4 sheets, map scale 1:250,000 Author: Oak Ridge National Laboratory
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
The data in this file have been processed using various formulas and methods that are not usually documented but that represent industry standard practices for airborne data reduction. For example, position is listed as latitude and longitude, but these values were derived from the raw navigation data depending on the system used. (see notes under horizontal accuracy). Line numbers were added to records, and unusable data at flight-line ends were discarded (as aircraft slowed and turned around). Separate recordings were correlated by time and assigned to the correct location. The exact accuracies of these processing steps may not be known. They are discussed in the sections on attribute or positional accuracies.
Logical_Consistency_Report:
The data in this file were collected by a single contractor or group who were responsible for collecting and processing the data. The data from this survey were collected using the same instruments (magnetometers, altimeters, radiometic crystal packages, navigational systems) throughout the survey and were collected in a normal length of time with no long delays between survey beginning and end. Survey contracts specified the conditions and specifications under which these data were collected. Standard industry practices of the time were followed in data collection and processing.
Completeness_Report:
Loss of data due to poor transmission, channel dropout, obvious spiking, missing channels, and other obvious errors were replaced with one of the Following values: -9999.9, -999.9, -99, etc. Sometimes channels were added and filled with dummy values (-9999.9, etc.) to comply with the established format. Records that had no usable data were deleted.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
Flight Path Recovery The horizontal position of the survey aircraft used to collect data was determined by reconciling down-looking photographs (recorded on continuous-strip film) with topographic maps and orthophotoquadrangle maps. Fiducial numbers and marks, impressed on any paper strips that were recording data or added to magnetic tape records, were included as a function of time to further reconcile location with instrumentation.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The aircraft vertical position was determined using the navigational positioning equipment on the aircraft, which were radar altimeter and barometric altimeter. Barometric altimeter data are not available for most of these data sets. Radar altimeters are estimated to have an error of 2-5% of the altitude (Richard Hansen, PRJ, Inc., written communication). The magnetometer was carried in a bird towed on a line about 60 feet below the aircraft. The bird as it is towed is slightly behind the aircraft and therefore the vertical distance between the magnetometer and the aircraft is less than the length of the line but remains constant for the survey.
Lineage:
Process_Step:
Process_Description:
Conversion of measured values to geographic position and magnetic and radiometric values was performed by the contractor using industry standard practices. Details are found under Attribute Accuracy Report, Horizontal_Position_Accuracy_Report, and Vertical_Position_Accuracy_Report Conversion processes, if reported, may be found in the U.S. Department of Energy's published GJO- or GJBX- reports for the quadrangle or group of quadrangles. Unpublished products generated by the contractor included magnetic tapes and perhaps some written documentation.
Process_Date: 1977
Process_Step:
Process_Description:
USGS reformatting of contractor data to standard format. USGS personnel used the software package Oasis Montaj version 6.3 by Geosoft, Inc., to read in the original contractor's data. Positioning and magnetic values were checked for obvious errors or spikes. Values of -9999.9,-999.9, -99.9, etc., were given where the value could not be reasonably corrected or, in some cases, the whole record was removed. Information that was missing from the data file but recorded elsewhere, such as year flown, was added th the file. The radiometric data were not checked for errors except for dummy values which were replaced with -99.9, -999.9, etc. The reformatted data files were written in the format described in the section on Entity_and_Attribute_Overview.
Process_Date: 2008
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: point
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 0.0001
Longitude_Resolution: 0.0001
Geographic_Coordinate_Units: decimal degrees
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1927
Ellipsoid_Name: Clarke 1866
Semi-major_Axis: 6,378,206.4
Denominator_of_Flattening_Ratio: 294.98
Vertical_Coordinate_System_Definition:
Altitude_System_Definition:
Altitude_Datum_Name: National Geodetic Vertical Datum of 1929
Altitude_Resolution: 0.1
Altitude_Distance_Units: meters
Altitude_Encoding_Method:
Explicit elevation coordinate included with horizontal coordinates
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
Airborne survey specifications These items are constant for the entire survey Project number: 6035I Project name: Mt. McKinley Quadrangle Survey flown by: Texas Instruments, Inc. Survey flown for: DOE Grand Junction Office Approx. no. of line miles: 1315 Survey height: 400 ft Altitude method: Draped over terrain Flight-line spacing: 6 miles Flight-line direction: East-West Aircraft used: Bell 212 helicopter Airport - arrival: unknown Airport - departure: unknown Magnetometer used: proton precession Sensor tow distance: 60 feet Radiometric crystal package volume: 3324 (down) & 415 (up) cu. in.
Entity_and_Attribute_Detail_Citation:
Nettleton, L.L., 1971, Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series No. 1, p. 83-87. Dobrin, M.B., 1976, Introduction to Geophysical Prospecting: New York, McGraw-Hill Book Company, p. 505-517. Grasty, R.L., and Holman, P.B., 1974, Optimum Detector Sizes for Airborne Gamma-ray Surveys: Geological Survey of Canada Paper 74-1, Part B, p. 72-74.
Entity_and_Attribute_Overview:
Aeromagnetics Each record contains the following 12 attributes: No name contents 1 line flight line number 2 fid fiducial number (integer) 3 time time (hhmmss) 4 day Julian day flown (integer) 5 year year flown (integer) 6 latitude latitude (decimal degrees) 7 longitude longitude (decimal degrees) 8 radalt radar altimeter reading above ground (meters) 9 totmag corrected magnetic value (nT) 10 resmag residual magnetic value (nT) 11 diurnal ground magnetometer value (nT) 12 geology surficial geology beneath flight line (coded)
Entity_and_Attribute_Overview:
Radiometrics Each record contains the following 21 attributes: No name contents 1 line flight line number 2 fid fiducial number (integer) 3 time time (hhmmss) 4 day Julian day flown (integer) 5 year year flown (integer) 6 latitude latitude (decimal degrees) 7 longitude longitude (decimal degrees) 8 radalt radar altimeter reading above ground (meters) 9 resmag residual magnetic value (nT) 10 geology surficial geology beneath flight line (coded) 11 qual quality flags of the radiometrics (integer) 12 app_K apparent Potassium as Potassium 40 (percent potassium) 13 app_U apparent Uranium as Bismuth 214 (parts per million equivalent uranium) 14 app_Th apparent Thorium as Thallium 208 (parts per million equivalent thorium) 15 U_Th_ratio ratio of Uranium and Thorium 16 U_K_ratio ratio of Uranium and Potassium 17 Th_K_ratio ratio of Thorium and Potassium 18 total_count total count of radioactivity (counts/second) 19 atmos_BI214 atmospheric Uranium as Bi214 (counts/second) 20 air_temp air temperature (degrees Celsius) 21 air_press air pressure (mmHg)
Entity_and_Attribute_Detail_Citation:
Nettleton, L.L., 1971, Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series No. 1, p. 83-87. Dobrin, M.B., 1976, Introduction to Geophysical Prospecting: New York, McGraw-Hill Book Company, p. 505-517. Parasnis, D.S., 1975, Mining Geophysics: Elsevier Scientific Publishing Company, Methods in Geochemistry and Geophysics vol. 3, p. 298-307.
Detailed_Description:
Entity_Type:
Entity_Type_Label: record for one magnetic or radiometric data point
Entity_Type_Definition:
The set of all measurements reported for a magnetic or radiometric data point having the same spatial location.
Entity_Type_Definition_Source:
Standard aeromagnetic and aeroradiometric data collection procedures as written in the contract for survey collection.
Attribute:
Attribute_Label: line
Attribute_Definition: flight line number
Attribute_Definition_Source: often assigned by airborne survey crew
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 23
Range_Domain_Maximum: 117
Attribute_Units_of_Measure: alphanumeric value
Attribute:
Attribute_Label: fid
Attribute_Definition:
A fiducial number is a mark which indicates points of simultaneity. It is a user-defined integer used during airborne operations to correlate recording devices (magnetometers) with navigational records (altimeters, camera film, strip charts) that were recorded at the same time.
Attribute_Definition_Source:
Sheriff, R.E., 1984, Encyclopedic dictionary of exploration geophysics: Tulsa, OK, Society of Exploration Geophysicists, p. 89.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1
Range_Domain_Maximum: 3595
Attribute:
Attribute_Label: time
Attribute_Definition:
time of data point collection. Time is given in either local time or Greenwich Meridian Time. Values of 999999 indicate missing data.
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Unrepresentable_Domain:
a range of time of day values has no meaning because the timeframe can span several days or weeks.
Attribute:
Attribute_Label: day
Attribute_Definition:
Julian day, where Jan. 1 = 1 and Dec. 31 = 365 or 366 (leap year)
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 211
Range_Domain_Maximum: 224
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation: Both beginning and end Julian dates were taken from dataset.
Attribute:
Attribute_Label: year
Attribute_Definition: year of data point collection
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 1977
Range_Domain_Maximum: 1977
Attribute:
Attribute_Label: latitude
Attribute_Definition: latitude - geographic coordinate
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 63.0003
Range_Domain_Maximum: 64.0002
Attribute_Units_of_Measure: decimal degrees
Attribute:
Attribute_Label: longitude
Attribute_Definition: longitude - geographic coordinate
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -152.9994
Range_Domain_Maximum: -150.0000
Attribute_Units_of_Measure: decimal degrees
Attribute:
Attribute_Label: radaralt
Attribute_Definition:
radar altimetry reading, in meters An aircraft navigational system in which short electromagnetic waves are transmitted, and the energy scattered back by reflection is detected. From this measurement, the distance between the aircraft and the ground is calculated and recorded as radar altimetry. Values of -999.9 indicate missing data.
Attribute_Definition_Source:
Sheriff, R.E., 1984, Encyclopedic dictionary of exploration geophysics: Tulsa, OK, Society of Exploration Geophysicists, p. 89.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 30.8
Range_Domain_Maximum: 821.4
Attribute_Units_of_Measure: meters
Attribute:
Attribute_Label: totmag
Attribute_Definition:
Raw magnetic value with base magnetometer corrections applied. Because the magnetic field of the earth varies diurnally, a stationary base magnetometer is maintained on the ground during airborne surveying. The base magnetometer records changes in the magnetic field (in nanoTeslas) as a function of time. The magnetic changes may have an amplitude of 20 to 50 nanoTeslas. If changes are more severe, as would occur from a magnetic storm, surveying is discontinued or the data recorded are not used. Diurnal variations are then removed from the airborne magnetic data based on the common time. Records containing missing data were usually deleted.
Attribute_Definition_Source:
see: Nettleton, L.L., 1971, Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series No. 1, p. 83-87. A description of magnetometers and how they measure the total magnetic field can be found in: Dobrin, M.B., 1976, Introduction to Geophysical Prospecting: New York, McGraw-Hill Book Company, p. 505-517.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 55900.0
Range_Domain_Maximum: 56709.0
Attribute_Units_of_Measure: nanoTeslas
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 2
Attribute_Value_Accuracy_Explanation:
The airborne magnetometer is accurate to about 1 nanoTesla, and the base magnetometer has the same accuracy. The accuracy of the base-corrected airborne value therefore is near 2 nanoTeslas or better.
Attribute_Measurement_Frequency:
The magnetometer has a recharging interval of 0.5 seconds. The data were recorded at 1 second intervals.
Attribute:
Attribute_Label: resmag
Attribute_Definition:
residual magnetic value The total magnetic value minus a geomagnetic reference field (GRF), which is a long-wavelength regional magnetic field. The most commonly used reference field is determined from a model developed by the International Association of Geomagnetism and Aeronomy (IAGA). The International Geomagnetic Reference Field (IGRF), is a predictive model adopted at the beginning of a model period (e.g. in 1989 for 1990-1995). After the model period, a revised definitive model is adopted, the DGRF. This is the preferred model to use for removing regional magnetic fields. For this survey, the field removed is probably IGRF 1965. Some contractors add a constant to the residual value in order to avoid negative values. This constant can vary from one data set to another. Values of -9999.9 indicate missing data.
Attribute_Definition_Source:
Nettleton, L.L., 1971, Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series No. 1, p. 83-87.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -112.0
Range_Domain_Maximum: 530.0
Attribute_Units_of_Measure: nanoTeslas
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 2
Attribute_Value_Accuracy_Explanation:
The Geomagnetic Reference Field that was subtracted from the total magnetic value is based on a model, which was updated to the date of the survey. New models are available at five year intervals. These models have varying degrees of accuracy in determining the local reference field.
Attribute:
Attribute_Label: diurnal
Attribute_Definition:
Base magnetometer values used to correct the total magnetic value. Because the magnetic field of the earth varies diurnally, a stationary base magnetometer is maintained on the ground during airborne surveying. The base magnetometer records changes in the magnetic field (in nanoTeslas) as a function of time called the diurnal. The magnetic changes may have an amplitude of 20 to 50 nanoTeslas. The diurnal is monitored during the survey and if changes are severe, as would occur from a magnetic storm, surveying is discontinued or the data recorded are not used. Diurnal variations are then removed from the airborne magnetic data based on the common time. Values of -9999.9 indicate missing data.
Attribute_Definition_Source:
see: Nettleton, L.L., 1971, Elementary Gravity and Magnetics for Geologists and Seismologists: Society of Exploration Geophysicists Monograph Series No. 1, p. 83-87. A description of magnetometers and how they measure the total magnetic field can be found in: Dobrin, M.B., 1976, Introduction to Geophysical Prospecting: New York, McGraw-Hill Book Company, p. 505-517.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 55674.7
Range_Domain_Maximum: 56599.5
Attribute_Units_of_Measure: nanoTeslas
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 2
Attribute_Value_Accuracy_Explanation:
The airborne magnetometer is accurate to about 1 nanoTesla, and the base magnetometer has the same accuracy. The accuracy of the base-corrected airborne value therefore is near 2 nanoTeslas or better.
Attribute_Measurement_Frequency:
The base magnetometer has a recharging interval of 0.5 seconds. The data were recorded at 2-4 second intervals.
Attribute:
Attribute_Label: geology
Attribute_Definition:
Geologic identification codes or numeric codes indicating the rock types immediately beneath the flight line. These codes were determined by plotting the flight lines on a surficial geologic map. A description of the codes can be found in the GJBX- or GJO- report for this quadrangle listed in the Cross Reference section above. Values of -99 indicate missing data.
Attribute_Definition_Source: original publication
Attribute_Domain_Values:
Unrepresentable_Domain: values are not quantified
Attribute:
Attribute_Label: apparent potassium
Attribute_Definition:
the apparent content of potassium in the surface rock and soil Values of -99.9 indicate missing data.
Attribute_Definition_Source:
Duval, J. S., 1990, Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States: Journal of Geochemical Exploration, vol. 39, no. 1-2, p. 249-253.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -998.3
Range_Domain_Maximum: 8294.2
Attribute_Units_of_Measure: percent potassium
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation:
Additional information can be found in the original GJBX- or GJO- report listed in the Cross_Reference section above.
Attribute_Measurement_Frequency: The data were recorded at 1-2 second intervals.
Attribute:
Attribute_Label: apparent uranium
Attribute_Definition:
the apparent content of uranium in the surface rock and soil Values of -99.9 indicate missing data.
Attribute_Definition_Source:
Duval, J. S., 1990, Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States: Journal of Geochemical Exploration, vol. 39, no. 1-2, p. 249-253.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -881.7
Range_Domain_Maximum: 8336.0
Attribute_Units_of_Measure: parts per million equivalent uranium (ppm eU)
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation:
Additional information can be found in the original GJBX- or GJO- report listed in the Cross_Reference section above.
Attribute_Measurement_Frequency: The data were recorded at 1-2 second intervals.
Attribute:
Attribute_Label: apparent thorium
Attribute_Definition:
the apparent content of thorium in the surface rock and soil Values of -99.9 indicate missing data.
Attribute_Definition_Source:
Duval, J. S., 1990, Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States: Journal of Geochemical Exploration, vol. 39, no. 1-2, p. 249-253.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -609.1
Range_Domain_Maximum: 4575.3
Attribute_Units_of_Measure: parts per million equivalent thorium (ppm eTh)
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation:
Additional information can be found in the original GJBX- or GJO- report listed in the Cross_Reference section above.
Attribute_Measurement_Frequency: The data were recorded at 1-2 second intervals.
Attribute:
Attribute_Label: total count
Attribute_Definition:
the gross effect of the content of uranium, thorium, and potassium in the surface rock and soil Values of -9999.9 indicate missing data.
Attribute_Definition_Source:
Pitkin, James A., 1968, Airborne measurements of terrestrial radioactivity as an aid to geologic mapping: U.S. Geological Survey Professional Paper 516-F, 29 p.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -39,121.3
Range_Domain_Maximum: 316,519.4
Attribute_Units_of_Measure: counts per second
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation:
Additional information can be found in the original GJBX- or GJO- report listed in the Cross_Reference section above.
Attribute_Measurement_Frequency: The data were recorded at 1-2 second intervals.
Attribute:
Attribute_Label: atmospheric bismuth 214
Attribute_Definition:
the atmospheric content of equivalent uranium determined by measuring the amount of its decay product bismuth 214. Values of -99.9 indicate missing data.
Attribute_Definition_Source:
Duval, J. S., 1990, Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States: Journal of Geochemical Exploration, vol. 39, no. 1-2, p. 249-253.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 37.2
Attribute_Units_of_Measure: parts per million
Attribute_Value_Accuracy_Information:
Attribute_Value_Accuracy: 1
Attribute_Value_Accuracy_Explanation:
Additional information can be found in the original GJBX- or GJO- report listed in the Cross_Reference section above.
Attribute_Measurement_Frequency: The data were recorded at 1-2 second intervals.
Attribute:
Attribute_Label: air temperature
Attribute_Definition:
temperature of the air in degrees Celsius Values of -999.9 indicate missing data.
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -999.9
Range_Domain_Maximum: -999.9
Attribute:
Attribute_Label: air pressure
Attribute_Definition:
pressure of the air measured in millimeters of mercury (mmHg) Values of -999.9 indicate missing data.
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -999.9
Range_Domain_Maximum: -999.9
Attribute:
Attribute_Label: qual
Attribute_Definition:
quality flags indicating the relative quality of the radiometric data. A description of the codes can be found in the GJBX- or GJO- report for this quadrangle listed in the Cross Reference section above. Values of -9999 indicate missing data.
Attribute_Definition_Source: original publication
Attribute_Domain_Values:
Unrepresentable_Domain: values are not quantified
Attribute:
Attribute_Label: U-Th ratio, U_K ratio, and Th_K ratio
Attribute_Definition:
The calculated ratios of uranium, thorium, and potassium. Values of -99.9 indicate missing data.
Attribute_Definition_Source: self evident
Attribute_Domain_Values:
Unrepresentable_Domain: ranges of values were not determined
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization:
Web site administration: U.S Geological Survey Central Publications Group
Contact_Address:
Address_Type: mailing address
Address:
Central Publications Group
USGS MS 902, Box 25046 DFC
City: Denver
State_or_Province: CO
Postal_Code: 80225-0046
Contact_Voice_Telephone: 303-236-5486
Resource_Description: USGS Open-File Report OFR 2009-1129
Distribution_Liability:
Although all data published on this web site have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ASCII
Format_Specification:
Magnetic data file Each line contains data in the following format, beginning with line 1 (no header included): line I6 fid I8 time I8 day I5 year I6 latitude F10.4 longitude F11.4 radalt F7.1 totmag F9.1 resmag F9.1 diurnal F9.1 geology A10 Radiometric data file Each line contains data in the following format, beginning with line 1 (no header included): line I6 fid I8 time I8 day I5 year I6 latitude F10.4 longitude F11.4 radalt F7.1 resmag F9.1 geology A10 qual A8 app_K40 F9.1 app_U_BI214 F9.1 app_Th_TL208 F9.1 U_Th_ratio F7.1 U_K_ratio F7.1 Th_K_ratio F7.1 total_count F10.1 atmos_BI214 F7.1 air_temp F8.1 air_press F8.1
File_Decompression_Technique: gunzip
Format_Version_Number: 2.1
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: http://pubs.usgs.gov/of/2009/1129
Fees: none
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Peter N Schweitzer
Contact_Organization: USGS Eastern Mineral and Environmental Resources Science Center
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing address
Address: 12201 Sunrise Valley Drive
City: Reston
State_or_Province: VA
Postal_Code: 20192-0002
Country: USA
Contact_Voice_Telephone: 703-648-6533
Contact_Facsimile_Telephone: 703-648-6252
Contact_Electronic_Mail_Address: pschweitzer@usgs.gov
Resource_Description: mount_mckinley_meta.txt
Distribution_Liability:
This dataset was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: CSV
Format_Information_Content: Flight-line airborne magnetic anomaly measurements
File_Decompression_Technique: gzip -d
Transfer_Size: 0.67986011505127
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Digital_Form:
Digital_Transfer_Information:
Format_Name: CSV
Format_Information_Content: Flight-line airborne radiometric measurements
File_Decompression_Technique: gzip -d
Transfer_Size: 1.3383722305298
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Fees: none
Metadata_Reference_Information:
Metadata_Date: 20141204
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: USGS Gravity and Magnetics contact
Contact_Address:
Address_Type: mailing address
Address:
U.S. Geological Survey
Box 25046 Mail Stop 964
Denver Federal Center
City: Denver
State_or_Province: CO
Postal_Code: 80225-0046
Contact_Voice_Telephone: 303-236-5652
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998

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