U.S. Geological Survey 1997 map Anchorage, AK U.S. Geological Survey http://agdc.usgs.gov/data/usgs/geology/ Johnsson, M.J. (ed.) Howell, D.G. (ed.) 1996 U.S. Geological Survey Bulletin B-2142 This dataset consists of a polygon coverage and associated attribute data derived from the onshore portion of the 1996 "Generalized Thermal Maturity Map of Alaska" compiled by M.J. Johnsson and D.G. Howell, which was published as Plate 1 in US Geological Survey Bulletin 2142: "Thermal Evolution of Sedimentary Basins in Alaska". The published map summarizes vitrinite reflectance and conodont alteration index data (both measure the thermal maturity of rocks) into generalized units that can be shown cartographically at 1:2,500,000. This digital dataset includes the 8 map units indicated on the original map. (5 thermal maturity levels; 2 rock or sediment type; 1 "no data"). The data quality of the generalized information is retained, with an attribute value for "certainty" whose value choices are "questioned" or "certain". Additional data retained in a look-up table are the maximum and minimum vitrinite reflectance and conodont alteration index values assigned to each thermal maturity level. This coverage is not intended to be a complete representation of the printed map. It does NOT include the following features: locations of individual vitrinite or conodont sample data points (these data are available in: Johnsson and others, 1992, USGS Open File Report 409, 3 diskettes); faults; offshore maturity data (from dredge and well samples); cities, glaciers, wells; inset maps and subsurface contours for the Colville basin and Cook Inlet; the correlation chart, text or references printed on the map. This coverage is intended to provide digital features (polygons) representing generalized thermal maturity units in Alaska for use in small-scale spatial analysis (statewide) with similar coverages such as geologic units,vegetation types, soils, etc. Johnsson, M.J., Pawlewica, M.J., Harris, A.G., and Valin, Z.C., 1992, Vitrinite reflectance and conodont color alteration index data from Alaska: Data to accompany the Thermal Maturity Map of Alaska: U.S. Geological Survey Open File Report 92-409, 3 Macintosh-formatted 3 1/2" high density (1.44 Mb) diskettes. 1997 Publication date = 1996 Complete None planned -176.0 -130.0 72.0 51.0 None Geology Thermal Maturity Temperature Vitrinite Conodont None Alaska None None None None none This coverage should not be copied or distributed without its associated metadata file. Intended use is at small scales (e.g. statewide, 1:2,500,000 etc.) only; enlargements of this data to scales greater than that at which they were originally compiled can lead to misinterpretation of data. The U.S. Geological Survey (Dept. of Interior) should be acknowledged as the data source in products derived from these data. Use of these data is not restricted; however, organizations, agencies, units of government or other users are responsible for its appropriate application. U.S. Geological Survey Alaska Section, Mineral Resource Surveys Program, Geologic Division GIS Support Staff mailing and physical address

4200 University Dr.

Anchorage AK 99508-4667 (907)-786-7495 http://agdc.usgs.gov/data/usgs/geology/images/maturity.gif Reduced-size image of the entire map extent, 712x563 pixels, 18k bytes. GIF D. C. Pray, J. M. Schmidt SunOS, 5.5.1, sun4u UNIX, ARC/INFO version 7.1.2 The completeness and quality of the generalized maturity data in the digital coverage is that of the published 1996 map, which itself summarized data released in 1992 and collected prior to that date (mainly since 1980). No recent data have been added. The geographic accuracy of the published map has been slightly degraded by the rubber-sheet operation. The following map features are not included in the digital representation: Offshore data, faults, glaciers,subsurface contours, cities, wells, inset maps, correlation chart, text and references. U.S. Geological Survey 1996 U.S. Geological Survey Miscellaneous Investigations Series Map I-2494 Washington, D.C. U.S. Government Printing Office 2500000 Paper map 1996 publication date Johnsson, M.J. Pawlewica, M.J. Harris, A.G. Valin, Z.C. 1992 U.S. Geological Survey Open File Report 92-409 2500000 floppy disk 1992 publication date The linework was digitized in 1997 from a paper copy of the 1996 map at the U.S. Geological Survey's Alaska Section (Geologic Division) facilities in Anchorge, AK. The original Transverse Mercator projection of the map (Central Meridian: 100*W; Scale factor: 0.926; Reference ellipsoid:(6371204m, 63712004m)) was converted to an Albersequal-area coverage in ARC/INFO (version 7.1.2). The resulting coverage did not align exactly with an Albers equal-area coverage of the Alaskan coastline, so a rubber-sheeting operation was performed using points along the coastline and major rivers to match an Albers equal area projection. Map unit (polygon) locations and attributes were checked by the person responsible for the digitizing, and spot-checked by one reviewer reviewer, by comparing a printed copy of the coverage to the published map. 1997 Vector Point 1575 String 3453 GT-polygon composed of chains 1576 Albers Conical Equal Area 55 65 -154 50 0.00000 0.00000 coordinate pair 1.0 1.0 meters North American Datum of 1927 Clarke 1866 6378206.4 294.98 MATURITY.PAT Attribute table of Maturity MATURITY Thermal-maturity units Generalized Thermal Maturity Map of Alaska, 1996. U Undermature M1 Mature I M2 Mature II O Overmature S Supermature Ig-M Igneous-Metamorphic Qs Quaternary sediments (unconsolidated) ND No data CERTAINTY Confidence of thermal-maturity unit Generalized Thermal Maturity Map of Alaska, 1996. C Certain Q Questioned MATURITY.DAT Explanation of thermal-maturity units in terms of vitrinite reflectance and conodont alteration index values used to define them. U.S. Geological Survey Bulletin 2142 MATURITY Thermal-maturity units Generalized Thermal Maturity Map of Alaska, 1996. U Undermature M1 Mature I M2 Mature II O Overmature S Supermature Ig-M Igneous-Metamorphic Qs Quaternary sediments (unconsolidated) ND No data RO-MIN Minimum vitrinite reflectance value occurring in a thermal maturity unit. U.S. Geological Survey Bulletin 2142 0 5.01 0.01 RO-MAX Maximum vitrinite reflectance value occurring in a thermal maturity unit. U.S. Geological Survey Bulletin 2142 0.01 8 0.01 CAI-MIN Minimum conodont alteration index value occurring in a thermal maturity unit. U.S. Geological Survey Bulletin 2142 0 5 0.01 CAI-MAX Maximum conodont alteration index value occurring in a thermal maturity unit. U.S. Geological Survey Bulletin 2142 0.1 8 0.01 Alaska Geographic Data Committee mailing and physical

4230 University Drive

Anchorage AK 99508-4664 agdcweb@usgs.gov Although these data have been processed successfully on a computer system at the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. The U.S. Dept. of Interior, nor any of its agencies are liable for misuse of the data, nor for any damage, transmission of viruses or computer contamination caused through transmission of these data sets. ArcInfo export 7.x Polygon data with attributes gzip -d and tar ftp://agdc.usgs.gov/pub/usgs/geology/maturity.tar.gz none 20030214 Peter N Schweitzer U.S. Geological Survey, ER Geologist mailing address

Mail Stop 954 12201 Sunrise Valley Drive

Reston VA 20192 USA 703-648-6533 703-648-6252 pschweitzer@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998