Mapping the Geology of South America
Abstract
The third edition of the Geological Map of South America (GMSA) at a scale of 1:5 million was developed by the Subcommission for South America of the Commission for the Geological Map of the World (CGMW). This third version has been prepared with the cooperation of the Ibero-American Association of Geology and Mining Surveys; the geological surveys of Argentina, Brazil, Chile, Colombia, Ecuador, Peru, and Uruguay; with help from several universities and research institutes.
The map was compiled by the Colombian Geological Survey and Geological Survey of Brazil following a methodology for integrating the geological information from each country. This was undertaken as follows: first, a new code was generated for each chronostratigraphic unit according to the proposed legend, by using digital layers provided by the geological survey of each country; second, symbols and colors were generated with patterns representative of the rock type and the colors depicting the geological ages; and third, a map with coded units was prepared at a scale of 1:5 million. With the objective of generalization and linking geological units by hand, the GMSA was printed at a scale of 1:3 million with the new codification. Next, the GMSA was scanned and georeferenced in order to generalize the geological units, faults and folds at a scale of 1:5 million. Once this was done, and despite the small-scale of the GMSA, the chronostratigraphic units, faults and folds were adjusted with the aid of shaded relief images (STRM from NASA) in order to improve the match between relief and the mapped geological units. Finally, the geology between countries was harmonized. Updating of the data for the GMSA was done through extensive consultation of internationally indexed, published papers. The map is based on a Polyconic Projection (Latitude × Longitude), centered on Meridian-59°, WGS-1984 datum. Data for offshore areas were taken from the Tectonic Map of South America at scale 1:5.9 million. Sea Floor Topography was taken from GEBCO 08 Grid, version 20100927, and the Crustal Age Grid: NCEI/NOAA. The geological map also includes the layers of Quaternary volcanoes, magnetic lineaments, kimberlites, carbonatites, high pressure metamorphic rocks (retro-eclogites) and extraterrestrial impact craters.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T21E0346G
- Keywords:
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- 1099 General or miscellaneous;
- GEOCHEMISTRY;
- 1199 General or miscellaneous;
- GEOCHRONOLOGY;
- 8199 General or miscellaneous;
- TECTONOPHYSICS;
- 8499 General or miscellaneous;
- VOLCANOLOGY