Originator: U.S. Geological Survey
Title: Generalized thermal maturity map of Alaska
Publication_Place: Anchorage, AK
Publisher: U.S. Geological Survey
Originator: Johnsson, M.J. (ed.)
Originator: Howell, D.G. (ed.)
Title: Thermal evolution of sedimentary basins in Alaska
Series_Name: U.S. Geological Survey Bulletin
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.
Currentness_Reference: Publication date = 1996
Maintenance_and_Update_Frequency: None planned
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
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.
Data_Set_Credit: D. C. Pray, J. M. Schmidt
Native_Data_Set_Environment: SunOS, 5.5.1, sun4u UNIX, ARC/INFO version 7.1.2
Contact_Position: GIS Support Staff
U.S. Geological Survey
Alaska Section, Mineral Resource Surveys Program, Geologic Division
Address_Type: mailing and physical address
Address: 4200 University Dr.