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Identification Information
Title: USGS Alaska Petroleum Systems Project: Northern Alaska Province, Nanushuk and Torok Formations Assessment Units and Assessment Input Forms
Originator: Houseknecht, David W. and Schenk, C.J.
Publication Place: Denver, Colorado
Publisher: U.S. Geological Survey, Central Energy Resources Science Center
Publication Date: 2018
Landing Page or Download(.zip):
Landing Page or Download(.zip):
Abstract: The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates a set of known or postulated oil and (or) gas accumulations sharing similar geologic, geographic, and temporal properties within the Total Petroleum System, such as source rock, timing, migration pathways, trapping mechanism, and hydrocarbon type. The Assessment Unit boundary is defined geologically as the limits of the geologic elements that define the Assessment Unit, such as limits of reservoir rock, geologic structures, source rock, and seal lithologies. The only exceptions to this are Assessment Units that border the Federal-State water boundary. In these cases, the Federal-State water boundary forms part of the Assessment Unit boundary.
Supplemenatal Information: Assessment Input Forms used during the assessment process have also been included in this data release. These forms can be found in the folder titled "AssessmentInputForms." Documentation describing these forms is also included.
Purpose: The purpose of these files is to define and illustrate the geographic limit and geologic boundaries of the Assessment Units within the defined Total Petroleum Systems, as required for the USGS National Assessment of Oil and Gas Project. The Assessment Units were used as the fundamental units for the assessment of undiscovered oil and gas. The assessment unit boundaries define the combined geologic limits of each Assessment Unit and are described and defined in the text portions of this assessment publication.
Progress: Completed
Frequency: As needed
Time Period of Content
Single Date
Date: 2017
Currentness: publication date
West Bounding Longitude: -166.2
East Bounding Longitude: -147.6
North Bounding Latitude: 71.5
South Bounding Latitude: 68.4
Zoom to the resource envelope
Point of Contact
Contact Position: Geologist
Address Type: mailing and physical address
Address: U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
City: Denver
State: Colorado
Postal Code: 80225
Telephone: 7036486466
Browse Graphic
Browse Graphic URL:
Browse Graphic Caption: USGS Nanushuk and Torok AUs (2018)
Browse Graphic Type: JPEG
Access: none
Use: Users of this geospatial database and geologic information derived there from should acknowledge the U.S. Geological Survey as the source of the data.
Theme Keywords
Theme Reference: USGS Thesaurus
Theme Topics: energy resources, natural gas resources, oil resources, petroleum
Theme Reference: USGS Energy Resources Thesaurus
Theme Keywords: National Assessment of Oil and Gas, Energy Resources, Oil, Natural Gas, Resource Assessment, Geology, Assessment Unit, Unconventional Assessment Unit, Continuous Assessment Unit
Place Keyword Thesaurus: Geographic Names Information System (GNIS)
Place Keyword: United States of America, State of Alaska, Northern Alaska, Nanushuk Northeast, Nanushuk Northwest, Nanushuk South, Torok Northeast, Torok Northwest, Torok South
Data Quality Information
Logical Consistency Report: The Assessment Unit boundary was defined on the basis of the surface and subsurface geology of the petroleum system elements, and oil and gas production, shows, and seeps related to the Assessment Unit. The province geologist was required to defend the geologic boundaries of each Assessment Unit in a formal geologic and petroleum system review meeting.
Completeness Report: The Assessment Unit was mapped in part on the data contained in the IHS Energy Group, WHCS data base for wells, and the Nehring Significant Oil and Gas Field File.
Positional Accuracy
Horizontal Positional Accuracy Report: The Assessment Unit boundary represents the gross boundary of the combined geologic elements that comprise the Total Petroleum System. The Assessment Unit boundary was mapped by the province geologist and the boundary line digitally transferred using ArcGIS.
Processing Steps
Step 1 Process Description: The province geologist mapped the Assessment Unit boundary on a hard copy or digital base map that contained data from IHS Energy Group, WHCS data base for wells, and the Nehring Significant Oil and Gas Field File. The province geologist then plotted all other available geologic, geophysical and geochemical data and information on the base map to assist in mapping the Assessment Unit boundary. Following review, the Assessment Unit boundary was digitally captured from the hard copy or digital base map using ArcGIS.
Step 1 Process Date: 2017
Step 2 Process Description: The attributes were added from the assessment output data file. These assessment results' attributes are published on the National Assessment of Oil and Gas Fact Sheet for each Province.
Step 2 Process Date: 2017
Spatial Reference Information
Geographic Latitude Resolution: 0.000001
Geographic Longitude Resolution: 0.000001
Geographic Coordinate Units: Decimal degrees
Geodetic Model
Horizontal Datum Name: North American Datum Of 1983
Ellipsoid Name: Geodetic Reference System 80
Semi-major Axis: 6378137.0
Denominator of Flattening Ratio: 298.257223
Distribution Information
Resource Description: Downloadable Data
Distribution Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. These data have been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Organization: USGS Information Services
Address Type: mailing address
Address: Box 25286 Denver Federal Center
City: Denver
State: Colorado
Postal Code: 80225
Telephone: 1-888-ASK-USGS
Fax: 303-202-4693
Metadata Reference Information
Metadata Creation Date: 20171115
Organization: U.S. Geological Survey, Central Energy Resources Science Center
Person: Christopher P. Anderson
Contact Position: GIS Analyst (contractor)
Address Type: mailing and physical address
Address: U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
City: Denver
State: Colorado
Postal Code: 80225
Telephone: 303-236-7773
Contact Instruction: For inquiries regarding this document, please include the metadata contact person's name, dataset name, and publication series and number.
Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata Standard Version: FGDC-STD-001-1998
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