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Open-File Report 97–470 A: Preface
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This digitally compiled map includes geology, oil and gas field centerpoints, and geologic provinces of Africa with some of these components extended 
into geographically adjacent areas. This digital compilation is an interim product of  the U.S. Geological Survey's World Energy Project (WEP) and part 
of a series on CD-ROM.  The goal of the WEP is to assess the undiscovered, technically recoverable oil  and gas resources of the world.  Results of this
assessment were reported in 2000 (see USGS DDS-60 ). 

The first version of this CD-ROM (97-470A) was published in 1997 (see Persits and others, 1997).
Changes in version 2.0 include:

1. All spatial data in geographic coordinates projected to the Mercator projection.

2. Data is provided in both  ESRI's new and more powerfull ArcGIS 8.1 as well as in ArcView 3.2 and ArcView 3.0 formats.

3. Certain off-shore provinces have been expanded to include the 4000 meters water depth.

4. Geologic description and estimated values for undiscovered oil and gas resources have been added to the geologic provinces.
    Up-dated histograms showing distribution of oil and gas resources by province have been added to the map.

5. AutoPlay, advanced design feature allows easier use and viewing of the data for Microsoft Windows users.

For the World Energy assessment, the World was divided into eight energy regions which correspond approximately with the economic regions of the world as defined by the U.S. Department of State.  Both Sub-Saharan (Region 7) and the North Africa (Region 2, in part) are represented on this CD-ROM.  The geologic map for Africa was compiled and synthesized from a 1:5,000,000 UNESCO geologic map (see References ). Specific details of the data sources are given in the metadata files on this CD-ROM.  Map units were combined to simplify the map when projected at a smaller scale and to maintain consistency with other regional maps.  Precambrian rocks are undivided.

Each region was divided into geologic provinces.  Province boundaries for Africa were delineated onshore using data from the UNESCO geologic (see References) and tectonic maps, (see References, 1 and 2 ); offshore the provinces were bounded originally by the 2000 meter bathymetric contour, but are now extended to the 4000 m from the UNESCO geologic map (see References).   Each province was assigned a unique number, the first digit of which is the region code.  The three digits of which to the right of the region number are the province code. An attempt was made to number the provinces in geographic order. In Northern Africa, the numbering starts in the northeast corner of Africa, a continuation of the numbering of the Middle Eastern provinces of Region 2. Numbering in Region 7 begins in the northwest part of the region, with the sequentially numbered provinces, north to south, west to east. 

The following people, with their responsibilities, were involved in producing this CD-ROM: 

Geologic legend and general guidance - Thomas S. Ahlbrandt (Project Chief)
Compilation of the digital maps in Arc/Info - Feliks Persits (USGS contractor) 
Geologic attribution - Feliks Persits, Thomas Ahlbrandt, Michele Tuttle, Ronald Charpentier, 
Michael Brownfield. 
Implementation of metadata- Feliks Persits 
ArcView project - Feliks Persits
Map design and verification - Feliks Persits 
Design of original Adobe Acrobat files  - Kenneth Takahashi 
CD-ROM implementation - Feliks Persits 
Coordination - Thomas S. Ahlbrandt (Project Chief) 
Scale 1:12,500,000

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U.S. Geological Survey Open File Report  97- 470A, ver. 2.0