1_README.TXT

Thermal Maturity of Sedimentary Rocks in Alaska:  
Digital Resources

by Mark J. Johnsson(1), Kevin R. Evans(2), and 
Heather A. Marshall(3)

U.S. Geological Survey Digital Data Series DD-54
Version 1.0

1999

Manuscript approved March 4, 1999

U.S. DEPARTMENT OF THE INTERIOR
U.S. GEOLOGICAL SURVEY

(1) Bryn Mawr College, Bryn Mawr, PA 19010
(2) Christmas Valley, OR 97641
(3) Newark, CA 94560

ISBN:  0-607-92298

PREFACE

This CD-ROM is an updated re-release of three USGS 
publications on the thermal maturity of sedimentary rocks in 
Alaska:

   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 (1992) version 1.1 (revised 1999)

   Generalized thermal maturity map of Alaska: U.S. 
   Geological Survey Miscellaneous Geologic Investigations 
   Map I-2494, scale 1:2,500,000 (1996). 

   Thermal evolution of sedimentary basins in Alaska: U.S. 
   Geological Survey Bulletin 2142, 131 p. (1996).

This release allows access to digital versions of these 
reports and to the data underlying them. An interface built 
around Adobe(r) Portable Document Format (PDF) allows easy 
navigation around these products, whereby they may be easily 
viewed and printed. In addition to the PDF files, data are 
provided in Microsoft(r) Excel format to allow manipulations 
in a spreadsheet program, and in ASCII format for export to 
more sophisticated database-management or other software. The 
"Generalized Thermal Maturity Map of Alaska" was produced 
using Environmental Systems Research Institute's ARC/INFO(r) 
Geographic Information System (GIS), and this CD-ROM includes 
the entire workspace needed to export these databases for use 
with ARC/INFO or other GIS software supporting the ARC/INFO 
format. In addition, industry-standard shapefiles are 
included to allow export to other GIS software.



SYSTEM REQUIREMENTS

This CD-ROM was produced in accordance with the ISO 9660
standard and Apple Computer's hierarchical file system (HFS)
standard. The minimum system requirements to use the data
with the software provided on this disc are as follows:

Macintosh
* Macintosh or compatible computer with a 68020 or higher 
   processor (PowerPC recommended)
* 8 megabytes RAM (16 MB recommended)
* Apple System Software version 7.0 or later (7.1.2 or later 
   recommended)
* 13-inch color monitor that can display 256 colors (16.7 
   million colors recommended)
* CD-ROM drive

Windows
* IBM or compatible personal computer with a 386 or higher 
   processor (486 required for ArcExplorer software, Pentium 
   recommended)
* Microsoft Windows 3.1 or higher (Windows 95 or Windows NT 
   recommended)
* 8 megabytes RAM (16 MB recommended)
* VGA color monitor that can display 256 colors (PCI card 
   that can display 16.7 million colors recommended,)
* CD-ROM drive

UNIX
* Almost any UNIX workstation should be capable of 
   manipulating these files, but please take note of the 
   following hardware and software requirements:
* CD-ROM drive

All platforms:
* Adobe Acrobat Reader 3.0 (included on this disc) or higher
   or other software that can translate PDF files.  If you 
   are using Acrobat Reader 2.1 or lower, you will need to 
   upgrade. Because of the many different variations of the
   UNIX operating system, we do not include UNIX versions of
   Adobe Acrobat Reader on this disk. The correct version may
   be obtained free of charge at http://www.adobe.com/.
* Microsoft EXCEL (version 5.0 or higher) or a database 
   manager is useful for manipulating data files
* A graphical PostScript editor, such as Adobe Illustrator 
   (version 7.0 or higher) is needed to edit the Encapsulated
   PostScript versions of the "Generalized Thermal Maturity 
   Map of Alaska." The map can be viewed and printed, but not 
   edited, with Adobe Acrobat Reader (included on this disk).
* GIS software capable of reading ARC/INFO coverages or 
   shapefiles, such as ArcExplorer (Windows NT and Windows 95
   only, included on this disk), is needed to take full 
   advantage of the GIS-capabilities of the "Generalized 
   Thermal-Maturity Map of Alaska."



QUICK START

For those already familiar with Adobe Acrobat Reader and who 
have version 3.0 or higher installed on their computer, go 
directly to the file "QuickStart.pdf".  This file consists of 
the opening pages of the PDF interface to this CD-ROM. The 
directories "Data" and "Map" also contain data files and 
ARC/INFO files not accessible through the PDF interface, for 
use by database and GIS software, respectively. More 
information is contained within the readme files for those 
directories, and in the rest of this file.



INSTALLING ADOBE ACROBAT READER SOFTWARE

The "Acrobat" directory (inside the "Utilities" directory) on 
this CD-ROM contains installers for Adobe Acrobat Reader 3.01 
for Windows ("PC" directory) and Macintosh ("Mac" directory).  
For Windows, a 16-bit version ("Windows" directory) is 
provided for Windows 3.1 and a 32-bit version ("Windows95-NT" 
directory) is provided for Windows 95 and Windows NT. Each 
installer is a self-extracting archive that opens in the 
directory you specify.  For Windows versions, once opened, 
run the Setup program to proceed.  You can use the installers 
provided on this disc or download the latest version of Adobe 
Acrobat Reader free via the Internet from the Adobe homepage 
on the World-Wide Web at http://www.adobe.com/.



INSTALLING ARCEXPLORER SOFTWARE (WINDOWS 95 and NT ONLY)

The "ArcExplorer" directory (inside the "Utilities" 
directory) on this CD-ROM contains an installer for ESRI 
ArcExplorer for Windows. To use ArcExplorer, you must have 
Microsoft Windows 95 or Microsoft Windows NT 4.0 or later 
installed on your system. The installer is a self-extracting 
archive that opens in the directory you specify. Once opened, 
run the Setup Wizard program to proceed. You can use the 
installer provided on this disc or download the latest 
version of ArcExplorer free via the Internet from the ESRI 
homepage on the World Wide Web at http://www.esri.com/



THE PDF INTERFACE TO THIS REPORT

To make best use of this CD-ROM, you will need to 
develop some familiarity with Acrobat Reader. An online 
guide is available within Acrobat Reader under "Help."

Install Adobe Acrobat Reader 3.0 if needed (see above for 
details).  Open the Adobe Acrobat Reader application, change 
to the CD-ROM device, and open the file QuickStart.pdf to 
view the CD-ROM title and opening pages. All of the products 
on this CD-ROM can be viewed and printed from this interface.
You can jump to the CD-ROM main menu by clicking a labeled 
button that is provided at the bottom of each page of the 
navigation menus, and on the first and last pages of the 
interpretive report (Bulletin 2142).  

If your copy of Acrobat Reader has "Open Cross-Document Links
In Same Window" selected (see the "General" section of the
"Preferences" dialog, accessible from the "File" menu), you
should deselect it.  This will keep the main document open
while you open and close other PDF files.

For oversize printouts, the user should choose "Page Setup"
from the "File" menu and match the page size to the paper
size in the printer.

This CD-ROM contains a full-text index (INDEX.PDX) and 
associated directory that is for use in searching the PDF 
files for words or sets of words using the Search feature 
under Tools in Acrobat Reader.



DATA STRUCTURES

All of the products on this CD-ROM can be viewed, searched, 
and printed using Adobe Acrobat Reader and the PDF interface 
described above. This interface is best entered from the main 
menu reached from the file "QuickStart.pdf," found in the 
root directory.

Some of these products may be used with more versatility in 
other applications. Accordingly, separate directories are 
provided for "data," "map," and "report," containing other 
versions of some of the files accessible through the PDF 
interface.

The "data" directory contains vitrinite reflectance (VR) and 
conodont color-alteration-index (CAI) data in three formats: 
a Microsoft Excel (version 5.0) workbook, a set of four ASCII 
files; and a set of four files in Adobe's PDF format, also 
accessible through the PDF interface described above. The 
Excel workbook contains four spreadsheets: one each for VR 
data from outcrops, VR data from wells, conodont CAI data 
from outcrops, and conodont color alteration index data from 
wells. These spreadsheets are neatly formatted and will 
generally be easier to work with than the ASCII or PDF files, 
but they do require that the user own a copy of the Microsoft 
Excel application. The ASCII files are tab-delineated, with 
the first two records consisting of a title and field labels, 
respectively. Manipulation of the ASCII files requires a 
database-management, spreadsheet, or word-processing program 
capable of reading ASCII files.

The "map" directory contains six subdirectories. The 
"outputfiles" directory contains the complete "Generalized 
Thermal Maturity Map of Alaska" in several file formats. The 
"coverages" directory contains the ARC/INFO coverages from 
which the map can be generated; these are described more 
fully in the file "readme.txt" within the "map" directory. 
The coverages also are provided in ESRI's "export" format 
(directory "exportfiles") and as GIS industry-standard 
shapefiles (directory "shapefiles"). The directory 
"insetfigures" contains the inset figures for the map, both 
as a Encapsulated PostScript file with font outlines and as 
an Encapsulated PostScript file with embedded fonts. Finally, 
the directory "miscfiles" contains the various linesets, 
shadesets, markersets, textsets, and the projection file used 
in creating the map. It also contains the file "plot.aml" 
used to create the Encapsulated PostScript file found in the 
"outputfiles" directory. These files are described more fully 
in the file "readme.txt" within the "map" directory.

The "report" directory contains a PDF version of the 
Bulletin, also accessible from the PDF interface described 
above.



CONTENTS

Files and directories found on this CD-ROM are as follows; 
directories end in a forward slash ("/"):

1_README.TXT (this file)

QuickStart.pdf (main menu for PDF interface)

Index.pdx (index file for doing searches in Adobe Acrobat 
   Reader)

Index/ (index files for use with Adobe Acrobat Reader)

Utilities/
   SimpleText (text reader for the Macintosh)
   ArcExplorer/
      aeclient.exe (ArcExplorer installer for Windows 95 and 
         NT)
   ACROBAT/  (Adobe Acrobat Reader and Search installers)
      MAC/
         OLE/
         QuickTime Installer/
         Reader/
         Search/
      PC/
         16BIT/
         32BIT/
         QUICKTIM/
Data/
   Readme.txt (data structures, sources, and methods)
   Readme.pdf (usually reached through PDF interface)
   Data.exl (VR & CAI data in Microsoft Excel Workbook 
      format)
   ASCIIfiles/ (VR & CAI data in ASCII format)
      CAIOutcrp.txt (CAI data from outcrops)
      CAIWells.txt (CAI data from oil wells)
      VROutcrp.txt (VR data from outcrops)
      VRWells.txt (VR data from oil wells)
   Explanation
      DataStructures.pdf (usually reached through PDF 
                interface)
      Methods.pdf (usually reached through PDF interface)
      Sources.pdf (usually reached through PDF interface)
   PDFFiles/ (VR & CAI data in PDF format, usually reached
                through PDF interface)
      CAIOutcrp.pdf (CAI data from outcrops)
      CAIWells.pdf (CAI data from oil wells)
      VROutcrp.pdf (VR data from outcrops)
      VRWells.pdf (VR data from oil wells)
Map/
   Readme.txt (data structures, explanations of files)
   Readme.pdf (usually reached through PDF interface)
   outputfiles/
      MapI2494.eps (Encapsulated PostScript version of
                 complete map)
      MapI2494.ai (Adobe Illustrator version of complete map)
      MapI2494.pdf (PDF version of complete map, usually
                reached through PDF interface)
      MAPI2494.tif (TIFF version of complete map)
   coverages/ (ARC/INFO coverages of map; each coverage, 
                contains many subdirectories and files 
                usually accessed only through the ARC/INFO 
                programming environment)
      base/ (base map that includes coastline, bathymetry, 
                and streams)
      akcanborder/ (special coverage for international 
                border)
      graticule/ (latitude-longitude lines)
      main/ (contacts, faults, and map units)
      outcrops/ (locations of outcrop data points)
      wells1/ (locations of selected oil wells with callouts
                describing thermal-maturity profile)
      wells2/ (locations of other oil wells used to constrain
                contours)
      contours/ (contoured depth to the U/M1 map unit 
                boundary in Colville and Cook Inlet Basins)
      towns/ (locations of major towns and cities)
      text/ (map annotation)
      info/ (INFO databases needed by ARC/INFO application)
   exportfiles/ (all of above ARC/INFO coverages in export
                format, needed to set up these files on your
                own hard disk)
   shapefiles/ (all of above ARC/INFO coverages in shapefile
                format for use with GIS software other than
                ESRI products)
   insetfigures/
      insets.ai (Adobe Illustrator version of
                inset figures)
      insets.eps (Encapsulated PostScript version of inset
                figures, needed by plot.aml to produce
                complete map)
   miscfiles/
      aktherm.lin (line set for use by ARC/INFO)
      aktherm.mrk (marker set for use by ARC/INFO)
      aktherm.shd (shade set for use by ARC/INFO)
      aktherm.txt (text set for use by ARC/INFO))
      fnt035 (font needed for line set aktherm.lin)
      dnag.prj (projection file to rotate latitude-longitude
                coordinates into map projection used by the 
                Geological Society of America in all of its 
                "Decade of North American Geology" products, 
                used in this map)
      plot.aml (Arc Macro Language program for producing
                complete map as ARC graphics and Encapsulated
                PostScript files)
      res2400.prm (parameter file for printing map)
      rot90.prm (parameter file for printing map)
      info/ (Directory containing files needed by INFO)
Report/ (interpretive report based on these data)
   Readme.txt
   Readme.pdf (usually reached through PDF interface)
   Bull2142.pdf (PDF version of USGS Bulletin 2142, usually
                reached through PDF interface)
version_history.txt (history of releases)


SUMMARY OF DATA AND INTERPRETATIONS

Alaska is a complex amalgamation of tectonic blocks with 
diverse histories. Sedimentary basins that are formed on 
these blocks both before amalgamation and as a result of 
collisions between them record the tectonic history of this 
complex region. Thermal-maturity data indicators of maximum 
burial temperatures provide important constraints both on 
basin evolution and on terrane amalgamation. To help 
elucidate these relations, and to provide constraints for 
hydrocarbon assessments, the U.S. Geological Survey (USGS) 
has compiled thermal-maturity data from Alaska for many 
decades. This report is a digital release of our current 
understanding of the thermal-maturity patterns in Alaska.

Sedimentary rocks in Alaska can be classified into at least 
four categories based on basin type and thermal-maturity 
pattern. The Tertiary interior basins are at very low thermal 
maturity, indicating that these basins are at or near maximum 
burial, have seen little uplift and exhumation, and probably 
are thermally immature at depth with respect to hydrocarbon 
generation. A second class of sedimentary rocks is found in 
the Aleutian forearc and backarc basins. These rocks are 
similarly at very low thermal maturity at the surface, except 
where near igneous heat sources (the Aleutian volcanoes). One 
of these basins, the Cook Inlet Basin (in the Aleutian 
forearc), shows greater thermal maturity at the basin 
margins, probably indicative of relatively greater uplift at 
the basin margins than at the basin center, which appears to 
be presently at its maximum burial depth. Uplift in the Cook 
Inlet Basin may reflect compression along the faults bounding 
the basin. A third class of sedimentary rocks is found in the 
Colville Basin on the North Slope. Thermal-maturity patterns 
in the Colville Basin are broadly asymmetric, indicating 
systematic differential uplift ranging from a minimum of no 
uplift in the north (Point Thomson area) to 9-13 km of uplift 
and exhumation in the central Brooks Range. This pattern may 
reflect deflexing of the lithosphere subsequent to the 
principal episode(s) of crustal convergence and thickening. 
Thermal-maturity isograds within the Brooks Range cut major 
thrust faults, indicating that maximum burial postdated the 
principal phases of thrusting. In contrast, isograds in the 
foothills belt to the north are warped broadly by local 
structure, indicating continued north-south shortening 
subsequent to maximum burial. A broad southward extension of 
thermally immature rocks in the central part of the foothills 
belt suggests relatively young east-west shortening (parallel 
to the strike of the orogen), a feature that to date has not 
been included in regional tectonic syntheses. The fourth 
major environment of sedimentary rocks in Alaska is in 
tectonically disturbed or dissected basin fragments. Many of 
these basins show elevated levels of thermal maturity at the 
surface, with higher values at basin margins. This geometry, 
particularly well documented in the Yukon-Koyukuk Basin, 
suggests a pattern of greater uplift along basin margins, 
possibly reflecting isostatic readjustments as crustal loads 
are removed by erosion. In the Kandik Basin of east-central 
Alaska, a thermal-maturity anomaly--thermally mature younger 
rocks in fault contact with thermally immature older rocks--
provides clues to the nature and timing of east-west 
thrusting. Mesozoic foreland basin deposits associated with 
thrusting buried Paleozoic rocks of the easternmost part of 
this fold-and-thrust belt to relatively shallow depths. The 
western foreland-basin deposits were overridden by advancing 
thrusts and tectonically buried as deep as 10 km.

These preliminary interpretations, based in part on USGS 
thermal-maturity data, are presented in graphical form as the 
"Generalized Thermal Maturity Map of Alaska" (Map I-2494) and 
as a series of papers in the book "Thermal Evolution of 
Sedimentary Basins in Alaska" (Bulletin 2142), both included 
on this disk. We hope that these materials will stimulate 
further interpretations based on these and additional data.



ACKNOWLEDGMENTS

The effort to compile all existing public thermal-maturity 
data from Alaska and to draw from those data a large-scale 
overview of the thermal-maturity patterns in Alaska was 
suggested by David G. Howell and Kenneth J. Bird, who have 
provided unstinting support throughout the many years of this 
project. We would like to express our sincere thanks to all 
those individuals who have contributed unpublished data or 
samples to this project; their names are listed in the 
acknowledgments of the individual products on this CD-ROM. 
Special thanks are extended to A.G. Harris, who made 
available her complete Alaskan inventory of conodont color-
alteration-index data, and M.J. Pawlewicz, who produced 
hundreds of vitrinite-reflectance determinations. Z.C. Valin 
extracted hundreds of vitrinite-reflectance determinations 
from industry reports and the literature; he and C.F. 
Hamilton also assisted with data input. Leslie B. Magoon was 
instrumental in organizing data collected over the past two 
decades by USGS scientists.  Assistance in the field was 
provided by David G. Howell, Michael B. Underwood, Donald L. 
Gautier, Christopher J. Schenk, Thomas Brocculeri, Lu Huafu, 
Paul B. O'Sullivan, William Arendt, Patrick McClung, Nomane 
Fehri, Francois Roure, and Pascal Desegaulx. T.T. Fitzgibbon 
and P.K. Showalter provided a tremendous amount of early 
assistance with ARC/INFO, and Karen Wheeler and Taryn 
Lindquist helped get the final map produced. Similarly, James 
W. Hendley II worked mightily to produce the final version of 
the Bulletin. Finally, we extend many thanks to Michael F. 
Diggles for his help and advice in producing this CD-ROM.



DISCLAIMER

This Compact Disc Read-Only-Memory (CD-ROM) publication was 
prepared by an agency of the United States Government.  
Neither the United States Government nor the agency thereof, 
nor any of their employees, makes any warranty, expressed or 
implied, or assumes any legal liability or responsibility 
for the accuracy, completeness, or usefulness of any 
information, apparatus, 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 trade name, 
trademark, manufacturer, or otherwise does not necessarily 
constitute or imply its endorsement, recommendation, or 
favoring by the United States Government or any agency 
thereof.

Although all data and software published on this CD-ROM have 
been used by the USGS, no warranty, expressed or implied, is 
made by the USGS as to the accuracy of the data and related 
materials and/or the functioning of the software.  The act 
of distribution shall not constitute any such warranty, and 
no responsibility is assumed by the USGS in the use of these 
data, software, or related materials.