Identification_Information: Citation: Citation_Information: Originator: Burns, L.E. Originator: SIAL Geosciences, Inc. Originator: On-line Exploration Services, Inc. Publication_Date: 2008 Title: Linedata and gridded data for the aeromagnetic survey of the Holitna basin area, western Alaska; Parts of the Lime Hills and Sleetmute quadrangles Geospatial_Data_Presentation_Form: raster digital data, tabular digital data, vector digital data Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2008-4 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 1 CD Online_Linkage: http://dggs.alaska.gov/pubs/gpdata/75 Description: Abstract: This DVD-ROM publication, GPR 2008-4, contains linedata, gridded data, vector data, and browse graphics produced from a fixed-wing aeromagnetic survey conducted in 1997 of the Holitna Basin area, western Alaska. Aeromagnetic data were acquired for about 3234 sq miles for the Alaska Division of Geological & Geophysical Surveys (DGGS) during this fixed-wing survey. Purpose: The survey was part of a Capital Improvement Project funded by the Alaska State Legislature at the request of Calista Native Corporation. The purpose of the Capital Improvement Project was to provide data to assist in evaluation of the hydrocarbon potential of the Holitna basin area. The survey was managed by State of Alaska, Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS). Supplemental_Information: The data were acquired, processed, and interpreted under contract between the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), and On-line Exploration Services, Inc. Aeromagnetic data for the area were acquired and processed by SIAL Geosciences, Inc. in 1997-1998. Some of the other publications for the CIP project are listed in the cross-references. More Holitna publications can be found by searching the DGGS publications for 'Holitna' at the DGGS Web site http://www.dggs.alaska.gov/pubs/advanced-search. Data provided in GPR 2008-4 include (1) processed and raw linedata ASCII files, (2) gridded files described below, (3) vector files of magnetic contours, flight path, and locational aids, and (4) a browse graphic file in PDF format. Gridded magnetic data include IGRF-removed total magnetic field, horizontal and vertical gradients (first derivatives), Euler deconvolution depth-to-basement models, and analytic signals. The Euler grids herein were produced by Sial Geosciences, Inc. and were included as page-sized color figures in the contractor's project report 'DGGS Public Data File 98-29', listed both as a source (SIAL and On-line, 1998) and as a cross reference in this metadata. Data are described in more detail in 'GPR2008-4Readme.pdf' and the browse-graphic file of this publication, and in the contractor's project report, referred to hereafter as 'SIAL and On-Line (1998)'. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 199707 Ending_Date: 200807 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -157.47 East_Bounding_Coordinate: -155.16 North_Bounding_Coordinate: 62.06 South_Bounding_Coordinate: 60.95 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: Aeromagnetic Data Theme_Keyword: Aeromagnetic Map Theme_Keyword: Aeromagnetic Survey Theme_Keyword: Airborne Geophysical Survey Theme_Keyword: Analytic Signal Theme_Keyword: Depth Interpretation Theme_Keyword: Euler Deconvolution Theme_Keyword: First Vertical Derivative Theme_Keyword: Fixed Wing Survey Theme_Keyword: Geophysics Theme_Keyword: Gridded Data Theme_Keyword: Horizontal Gradient Theme_Keyword: Linedata Theme_Keyword: Shaded Relief Place: Place_Keyword_Thesaurus: none Place_Keyword: Alaska, State of Place_Keyword: Farewell Fault Place_Keyword: Holitna Basin Place_Keyword: Lime Hills Quadrangle Place_Keyword: McGrath Mining District Place_Keyword: Sleetmute Quadrangle Place_Keyword: Yentna Mining District Access_Constraints: This report, map and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below). Use_Constraints: Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS). Browse_Graphic: Browse_Graphic_File_Name: GPR2008-4BrowseGraphic.pdf Browse_Graphic_File_Description: The browse graphic file, 'GPR2008-4BrowseGraphic.pdf' contains images of all the geophysical grids contained in this publication and a shaded-relief image of the total magnetic field. Included figures are Figure 1a: Total field magnetic map of the Holitna survey map area; Figure 1b: Total field magnetic map of all the Holitna survey data; Figure 2a: Horizontal gradient (dx) of the Holitna magnetic grid; Figure 2b: Horizontal gradient (dy) of the Holitna magnetic grid; Figure 2c: First vertical derivative (dz) of the Holitna magnetic grid; Figure 3: Color shadow map of the total field magnetic data; Figure 4a: Depth interpretation using Euler deconvolution with dike model, log-linear color method; Figure 4b: Depth interpretation using Euler deconvolution with step model, log-linear color method; Figure 4c: Depth to basement model using Euler deconvolution with dike model, log-linear color method; Figure 4d: Depth to basement model using Euler deconvolution with dike model, normal distribution color method; Figure 4e: Depth to basement model using Euler deconvolution with dike model, histogram equalization color method; Figure 5a: Analytic signal of the total magnetic field computed using Fast Fourier Transforms (FFT) for the z-derivative; log-linear color method; Figure 5b: Analytic signal of the total magnetic field computed using Fast Fourier Transforms (FFT) for the z-derivative; normal distribution color method; Figure 5c: Analytic signal of the total magnetic field computed using Fast Fourier Transforms (FFT) for the z-derivative; histogram equalization color method; Figure 5c: Analytic signal of the total magnetic field computed using Fast Fourier Transforms (FFT) for the z-derivative; histogram equalization color method; and Figure 5d: Analytic signal of the total magnetic field computed using convolution for the z-derivative; histogram equalization color method. Browse_Graphic_File_Type: PDF Data_Set_Credit: The Alaska State Legislature provided funding for the geophysical data and project management through a Capital Improvement Project requested by Calista Native Corporation. Native_Data_Set_Environment: Microsoft Windows XP Professional Version 2003 Service Pack 3; Geosoft Oasis Montaj Version 6.4.1; Autocad Version 13; and Adobe Distiller 8.1.0; Adobe Acrobat 5.0 Cross_Reference: Citation_Information: Originator: Alaska Division of Geological & Geophysical Surveys Staff Originator: On-line Exploration Services, Inc. Originator: SIAL Geosciences, Inc. Publication_Date: 1998 Title: Total field magnetics of the Holitna Basin area, western Alaska Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 98-14 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: color, 2 sheets, scale 1:125,000, data contours included, no topography Online_Linkage: http://dx.doi.org/10.14509/2589 Cross_Reference: Citation_Information: Originator: Alaska Division of Geological & Geophysical Surveys Originator: On-line Exploration Services, Inc. Originator: SIAL Geosciences, Inc. Publication_Date: 1998 Title: Total field magnetics and field line paths of the Holitna Basin area, western Alaska Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Public Data File Issue_Identification: PDF 98-27 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: black and white, 4 sheets, scale 125,000, topography included Online_Linkage: http://dx.doi.org/10.14509/1853 Cross_Reference: Citation_Information: Originator: SIAL Geosciences, Inc. Originator: On-line Exploration Services, Inc. Publication_Date: 1998 Title: Project report of the aeromagnetic survey for the Holitna Basin area, western Alaska Geospatial_Data_Presentation_Form: document, map Series_Information: Series_Name: Public Data File Issue_Identification: PDF 98-29 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 82 p., 2 interpretative sheets, scale 1:125,000 Online_Linkage: http://dx.doi.org/10.14509/2589 Cross_Reference: Citation_Information: Originator: LePain, D.L. Originator: Blodgett, R.B. Originator: Clough, J.G. Originator: Ryherd, T.J. Publication_Date: 2000 Title: Generalized stratigraphy and petroleum potential of the Holitna region, southwest Alaska Geospatial_Data_Presentation_Form: document, map Series_Information: Series_Name: Preliminary Interpretive Report Issue_Identification: PIR 2000-1 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 34 p., 1 sheet, scale 1:250,000 Online_Linkage: http://dx.doi.org/10.14509/2665 Cross_Reference: Citation_Information: Originator: LePain, D.L. Originator: Blodgett, R.B. Originator: Clough, J.G. Publication_Date: 2003 Title: Sedimentology and hydrocarbon source rock potential of Miocene-Oligocene strata, McGrath Quadrangle: An outcrop analog for the Holitna Basin Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: Preliminary Interpretive Report Issue_Identification: PIR 2002-5 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 75 p. Online_Linkage: http://dx.doi.org/10.14509/2870 Cross_Reference: Citation_Information: Originator: Edcon, Inc. Publication_Date: 2001 Title: Edcon land gravity survey, Holitna Basin, southwest Alaska Geospatial_Data_Presentation_Form: map, document, raster digital data, tabular digital data Series_Information: Series_Name: Geophysical Report Issue_Identification: GPR 2001-1 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 1 disk Online_Linkage: none Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Survey contracts specified the conditions and specifications under which these data were collected. Pre-survey Figure of Merit (FOM), Bourget calibrations, and lag tests were conducted between Sept. 1st and Sept. 7th, 1997. After spikes in the magnetic data were detected on September 22nd, a new magnetic sensor was installed and a new FOM was performed. Field barometric corrections were based on pre- and post-flight measurements made over the airstrip. Further discussion of calibrations and test results are given in the contractor's project report (SIAL and Online, 1998). Logical_Consistency_Report: Data for this survey were collected by a single subcontractor, SIAL Geoscience, Inc. who was responsible for collecting and processing the data. Most vector files are provided in both Autocad DXF and Geosoft PLT format in this publication; while containing the same information, the DXF files are better most of the time for large plots and the PLT files are generally better for smaller figures. No topological relationships are included. Completeness_Report: Data are complete. No dummy values were used in the linedata. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The position of the Piper Navajo 310 airplane position was derived every 1.0 second using post-flight processing to a relative accuracy of better than 5 m. Positional accuracy of the presented data is better than 10 m with respect to the UTM grid. Further inaccuracies may be introduced by the interpolation and gridding process. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The survey was flown draped over topography with a constant terrain clearance specification of 300 feet. A King KRA-10 radar altimeter with a resolution of 4 mV/foot, an accuracy of 1 percent over flat terrain, and better than 10 feet sensitivity was used. A Rosemount 1241 barometric altimeter was used with a resolution of 1 mV/foot, an accuracy of +/- 7 feet, and electronic drift less than 10 feet/hour. Further discussion of altimetry data are given in Sial and On-line (1998). Lineage: Source_Information: Source_Citation: Citation_Information: Originator: SIAL Geosciences, Inc. Publication_Date: Unpublished material Title: Geophysical data for the Holitna basin area, western Alaska Geospatial_Data_Presentation_Form: raster digital data, tabular digital data, vector digital data Type_of_Source_Media: CD-ROM Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: 1998 Source_Citation_Abbreviation: SIAL, 1998 Source_Contribution: The linedata files, the grid files Mag_MapArea.grd, EulDepDk.grd, EulDepSt.grd, and Depth2Basement_MapArea.grd, and the vector files (.PLT and .DXF formats) were renamed and copied onto this publication. Column names for final linedata were taken from this CD-ROM. The final linedata file was used as the basis for the other grids included in this publication. Source_Information: Source_Citation: Citation_Information: Originator: SIAL Geosciences, Inc. Originator: On-line Exploration, Inc. Publication_Date: 1998 Title: Project report of the aeromagnetic survey for the Holitna Basin area, western Alaska Geospatial_Data_Presentation_Form: map, document Series_Information: Series_Name: Public Data File Issue_Identification: PDF 98-29 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Other_Citation_Details: 82 p., 2 interpretative sheets, scale 1:125,000 Online_Linkage: http://dx.doi.org/10.14509/2589 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: 1998 Source_Citation_Abbreviation: SIAL and On-line, 1998 Source_Contribution: Much of the information in this metadata file, particularly the process steps, was taken from this report. Columns names for the raw linedata were taken from this report. Process_Step: Process_Description: The geophysical data were acquired with a RMS GR-33/HDS60 data acquisition system, and a Geometrics G822A cesium magnetometer installed in a stinger configuration in a Piper Navajo 310 airplane. In addition, the survey recorded data from a radar altimeter (King KRA-10), GPS navigation system, and video camera. Flights were performed at a mean terrain clearance of 300 ft along N35W survey flight lines with a spacing of one-half mile. Tie lines were flown perpendicular to the flight lines at intervals of approximately three miles. Two Trimble-4000 SE Differential Post-processing Global Positioning Systems were used for navigation and flight path recovery. The GPS receivers locked on to at least 4 satellites. Post-processing position accuracy was better than 5 meters. The data were acquired during September 8th and October 7th, 1997. The barometric altimeter was calibrated with the radar altimeter pre- and post- each flight. The 'drift' for the barometric altimeter was determined by flying over an airstrip of known elevation at several altitudes. This drift and the GPS altitude were used to correct the barometric altitude of each flight. Source_Used_Citation_Abbreviation: SIAL and On-line, 1998 Process_Date: 1997 Process_Step: Process_Description: The airborne magnetic data were acquired with a sampling interval of 0.1 seconds, and were corrected for measured system lag. Data from airborne and base magnetometers were inspected in order to remove discrete spikes and cultural noise. A 30 second low-pass filter was applied to remove small amplitude noise. Diurnal corrections were applied to the airborne magnetic data and the IGRF was removed. Final leveling was done by intersection analysis. A constant was added back to this residual data. The total field magnetic data were then interpolated onto a 200-m grid using GEOSOFT minimum curvature gridding to produce the grid 'Mag_MapArea.grd' in Geosoft short format, included in this publication. Source_Used_Citation_Abbreviation: SIAL and On-line, 1998 Process_Date: 1998 Process_Step: Process_Description: Euler deconvolution was used to produce the depth-to-basement grids, shown in the browse graphic file as Figures 4a-e and in the SIAL and On-line (1998) as Figures 40, 41, and 42. Dike and step source geometries were used. The dike model gave a maximum basement depth of 6490 meters and the step model give a maximum basement depth of 5350 meters. Blank regions on figures 4a and 4b are areas where no Euler solutions were found. Because the dike model was more compatible with the spectral analysis results discussed in SIAL and On-line (1998), SIAL filled in the indeterminate areas in the dike model grid and considered it as the best depth-to-basement model they produced. In order to fill in the indeterminate areas, the data were regridded with a longer radius by SIAL. The Geosoft short data format grids, EulDepDk, EulDepSt, and Depth2Basement were produced as a 200-m grid. Source_Used_Citation_Abbreviation: SIAL and On-line, 1998 Process_Date: 1998 Process_Step: Process_Description: After much investigation, all appropriate files on the CD-ROM provided by SIAL were selected for this publication. The final linedata were imported into Geosoft's Oasis Montaj and were used as the basis for the processes described here. Resulting grids mentioned here were all produced in Geosoft float format. The total field magnetic data were interpolated onto a 200-m grid using minimum curvature gridding to produce the grid 'mag.grd'. The grids dx, dy, and dz were produced using the Source Parameter Imaging (SPI) function, a trademark of Geoterrex. Two analytic signal grids were produced by applying filters to the magnetic grid. One method applied a Fast Fourier transform (FFT) to acquire the vertical derivative, and the other used convolution to acquire the vertical derivative. Both are included. Images of all of the gridded data on this CD-ROM are included in the browse-graphic file, GPR2008-4BrowseGraphic.pdf. A shaded-relief (color shadow) image of the magnetic grid was also produced and included. The figures were produced in Oasis Montaj and printed to Adobe Acrobat files. Source_Used_Citation_Abbreviation: SIAL, 1998 Process_Date: 2008 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 4 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -159 Latitude_of_Projection_Origin: 0 False_Easting: 500000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 200 Ordinate_Resolution: 200 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.978698 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Entities (file names) as well as the attributes of the linedata files are listed in the 'GPR2008-4Readme.pdf' file included on this CD-ROM. Entity_and_Attribute_Detail_Citation: L.E. Burns, Division of Geological & Geophysical Surveys and SIAL Geosciences, Inc. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Contact_Position: Natural Resource Technician Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5020 Contact_TDD/TTY_Telephone: None available Contact_Facsimile_Telephone: 907-451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please view our Web site (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address above whenever possible. Resource_Description: Geophysical Report 2008-4 Distribution_Liability: The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft binary short (GRD) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft binary float (GRD) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft projection file (.gi) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft ASCII linedata (XYZ) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft import template (.i3) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Geosoft plot (PLT) Format_Version_Number: Unknown Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: Autocad Vector (DXF) Format_Version_Number: 13 Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Digital_Form: Digital_Transfer_Information: Format_Name: PDF Format_Version_Number: 1.3 Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO9660 or Joliet Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dggs.alaska.gov/pubs/gpdata/75 Fees: Digital files on CD-ROM are available for $10 plus shipping; currently, only the maps can be downloaded from our web site (http://www.dggs.alaska.gov) and are in PDF format. No fees charged for downloaded files. Ordering_Instructions: Order by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: cash, check, money order, VISA, or MasterCard. The geophysics page of the DGGS web site (http://www.dggs.alaska.gov/pubs/geophysics) has geophysical order forms for this project and others. Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround: Digital downloads: less than 30 minutes for most files. Free FTP access is available upon request for files not available on the web. Offline CD/DVD-ROMs: 1-2 weeks unless special arrangements are made and an express fee is paid. Custom_Order_Process: Custom views or processing may be requested. Please contact Laurel Burns by phone (907-451-5021), e-mail (laurel.burns@alaska.gov), or fax (907-451-5050) to discuss custom processing availability, fees, and turnaround time. Technical_Prerequisites: Software with ability to use, import, or convert Geosoft .grd files, Geosoft .xyz (ASCII) files, Autocad .dxf files, Adobe Acrobat files, and text files. Free downloadable interfaces for accessing the gridded and dxf files are available at the Geosoft Web site (http://www.geosoft.com; Oasis Montaj viewer), and the ER Mapper Web site (http://www.ermapper.com). Maps are accessed digitally using Adobe Acrobat. Maps are printed from the Adobe Acrobat files. Metadata_Reference_Information: Metadata_Date: 20080723 Metadata_Review_Date: 20080723 Metadata_Future_Review_Date: 20110723 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS) Contact_Position: Geophysicist Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5021 Contact_TDD/TTY_Telephone: None available Contact_Facsimile_Telephone: 907-451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays. Contact_Instructions: Please contact us through the e-mail address above whenever possible. Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Access_Constraints: none Metadata_Use_Constraints: If the user has modified the data in any way the user is obligated to describe the types of modifications the user has made in the supporting metadata file. User specifically agrees not to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.