www.geopubs.co.uk

updated: 18 October 1999

The International Metallogenic Map of Africa is published under the auspices of the Commission for the Geological Map of the World (CGMW), with financial support from UNESCO. Compilation of the background geology involves up-dating and simplification of the CGMW's third edition of the 1:5 000 000 scale Geological Map of Africa, in accordance with the legend devised by CGMW for the Mineral Map of Africa.

P.A. Routhier initiated the project in 1975, A. Blanchot compiled an experimental first draft (1978), and A. Emberger drafted the final legend (1984) and compiled Sheet 1 (West Africa) of the International Mineral Map of Africa (1991). E.C.I. Hammerbeck succeeded Emberger in 1992 as General Coordinator and in 1994 Ms. Milica Veselinovic-Williams was assigned to the project as main author and commenced with the systematical compilation of a mineral deposits data base and background geology, giving priority to Sheets 5 and 6 (Subequatorial Africa).The present production is the culmination of this work.

Once the remaining Sheets 2 and 3 of the map are completed, and Sheet 1 is revised in GIS format, conventional printed maps will be produced. In the mean time, the data are released in digital format to promote mineral exploration in Africa. While the depth of data on individual deposits is limited, owing to the scale of the map, the strength of the digital data provided lies in the GIS data model, designed to facilitate comprehensive metallogenic analysis.

The ARC/INFO Geographic Information System (GIS) database consists of several data layers, namely:

A data layer for chronostratigraphy (GMS), documenting the lithology and the age of the rock formations.

A data layer for the geotectonic environment (GME), characterising the following domains:

a platform environment, within which continental, marine and paralic environments can be distinguished,

an orogenic environment, allowing for a distinction between pre-, syn-, or late/post-tectonic intrusions, and an anorogenic environment, with data on plutonic and hypabyssal intrusions.

A data layer for orogenic domains (GMO), documenting information about various orogenic events, and their time span, as well as for stable, cratonic terranes.

A layer for structural data (GSR), showing faults and thrusts.

A layer for mineral deposits (MINPOINT), recording the following information: position (Lat/Long), name of deposit, commodities, size, shape and orientation of deposits.

The data is stored in a DIGITMAP directory and organized in three subdirectories, namely: Arc/Explorer, Arc/View and Arc/Info.

The software Arc/Explorer of the Environmental Systems Research Institute Inc. (ESRI) is provided for viewing, querying and printing data. The file subafr.AEP is stored on the Arc/Explorer subdirectory and includes various data layers (themes) created initially on Arc/View software as a shape file (.shp). The look-up tables are provided in DBFformat.

The file subafr.APR, stored on the Arc/View subdirectory, consists of various shape file themes, created from Arc/Info.e00 files. Data are often explained under Theme Properties and Table Properties. Towns and political boundaries are obtained from ESRI’s digital world map data, updated in places.

AFRMTM001D - £650-00

Link to Geopubs Home Page

e-mail: info@geopubs.co.uk