Metadata: Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2016 Title: Aerorad data Geospatial_Data_Presentation_Form: raster digital data Larger_Work_Citation: Citation_Information: Originator: Susan M. Karl (ed.) Originator: James V. Jones, III (ed.) Originator: Timothy S. Hayes (ed.) Publication_Date: 2016 Title: GIS-based identification of areas that have resource potential for critical minerals in six selected groups of deposit types in Alaska Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 2016-1191 Other_Citation_Details: The larger work includes data sets for mineral resource data, geochemistry (stream sediment, rock, soil, mineral, and heavy mineral concentrate), igneous rock geochemical indices, lithology, and aeroradiometric data. Online_Linkage: http://dx.doi.org/10.3133/ofr20161191 Description: Abstract: Includes three raster files with data for thorium, uranium, and thorium/potassium ratios from aerial gamma-ray surveys in Alaska. Data was originally collected by contractors for the U.S. Department of Energy as part of the National Uranium Resource (NURE) program during the summer months of 1975, 1976, 1977, 1979, and 1980. For most of the surveys, the flight line spacings are 10km and the lines are oriented east-west. The nominal altitude of the aircraft above the ground was 122 meters. The U.S. Geological Survey processed these data to correct scaling differences between surveys and to convert count rate data to concentration values for potassium, uranium, and thorium. The processed data were used to calculated grids with 5km grid cells. Purpose: Aerial gamma-ray surveys capture the radioactive signatures of bedrock and surficial materials. The surveys measured the flux of gamma rays emitted as a result of the radioactive decay of the naturally occurring radioactive elements 40K, 238U, and 232Th. In this study, the processed data is used in the analyses for REE-Th-Y-Nb, sandstone uranium, and Sn-W-Mo in specialized granite deposit models. Supplemental_Information: The aerial gammy-ray surveys were originally published in Duval, Joseph S., 2001, Aerial gamma-ray surveys in Alaska: U.S. Geological Survey Open-File Report 01-128. http://pubs.usgs.gov/of/2001/of01-128/ Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1976 Ending_Date: 1980 Currentness_Reference: The aerial surveys were flown in 1976, 1977, 1979, and 1980. Status: Progress: Complete Maintenance_and_Update_Frequency: Unknown Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -168.3 East_Bounding_Coordinate: -129.9 North_Bounding_Coordinate: 71.4 South_Bounding_Coordinate: 54.6 Keywords: Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: NURE Theme_Keyword: National Uranium Resource Evaluation Theme_Keyword: gamma-ray Theme_Keyword: potassium Theme_Keyword: uranium Theme_Keyword: thorium Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation, 008 Place: Place_Keyword_Thesaurus: Geographic Names Information System Place_Keyword: Alaska Access_Constraints: None Use_Constraints: None. Users are advised to read the publication text and metadata to understand the appropriate use and data limitations. Data_Set_Credit: Joseph S. Duval and Keith Labay Native_Data_Set_Environment: The previously published raster data sets were converted to tif files using ESRI ArcGIS, version 10.2. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The concentration values are estimated to be no better than about +/- 30 percent except for areas of very low concentrations. Those areas are suspected to have water at or very near the surface and the measured concentrations do not represent the rocks or soils. Logical_Consistency_Report: Unknown Completeness_Report: Approximately 80 percent of Alaska is covered by aerial survey with line spacings of 10km. Less than one percent of the land surface was measured by these surveys. Lineage: Process_Step: Process_Description: The original survey data were processed to correct scaling differences between surveys and to convert count rate data to concentration values. Source_Used_Citation_Abbreviation: Duval, Joseph S., 1999, Aerial gamma-ray surveys of the conterminous United States and Alaska: U.S. Geological Survey Open-File Report 99-562. Process_Date: 2000 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Joseph S. Duval Contact_Position: Geophysicist Contact_Address: Address_Type: mailing address Address: 12201 Sunrise Valley Drive Mail Stop 954 City: Reston State_or_Province: VA Postal_Code: 20192 Country: USA Contact_Voice_Telephone: 703-648-6106 Contact_Electronic_Mail_Address: jduval@usgs.gov Process_Step: Process_Description: Raster file thorium_potassium_ratio.tif was created by dividing the thorium raster by the potassium raster as produced by Duval, 2001. Process_Date: 2014 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Keith Labay Contact_Address: Address_Type: mailing and physical Address: 4210 University Drive City: Anchorage State_or_Province: AK Postal_Code: 99508-4626 Country: USA Contact_Voice_Telephone: 907-786-7410 Contact_Electronic_Mail_Address: klabay@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 16501 Column_Count: 22401 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: NAD_1983_Alaska_Albers Albers_Conical_Equal_Area: Standard_Parallel: 55.0 Standard_Parallel: 65.0 Longitude_of_Central_Meridian: -154.0 Latitude_of_Projection_Origin: 50.0 False_Easting: 0.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 5 Ordinate_Resolution: 5 Planar_Distance_Units: kilometer Geodetic_Model: Horizontal_Datum_Name: NAD83 Ellipsoid_Name: GRS_1980 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257222101 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Rasters thorium_grs.tif and uranium_grs.tif were converted from the grd files as published in Duval, 2001. The cell value is concentration of thorium or uranium in parts per million. Raster thorium_potassium_ratio.tif is the result of dividing the thorium raster by the potassium raster as published by Duval, 2001. Entity_and_Attribute_Detail_Citation: Duval, 2001 and this data set Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing Address: MS902 Box 25286 Denver Federal Center City: Lakewood State_or_Province: CO Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 1-888-ASK-USGS Resource_Description: USGS Open-File-Report 2016-1191 Distribution_Liability: This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied or assumes any legal liability or responsibility for the accuracy, 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 trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: geotiff Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.3133/ofr20161191 Fees: none Metadata_Reference_Information: Metadata_Date: 20151215 Metadata_Review_Date: 20160906 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Nora Shew Contact_Address: Address_Type: mailing and physical Address: 4210 University Drive City: Anchorage State_or_Province: AK Postal_Code: 99508-4626 Country: USA Contact_Voice_Telephone: 907-786-7445 Contact_Electronic_Mail_Address: nshew@usgs.gov Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998