MINERAL EXPLORATION IN COVERED AREAS

Forty five percent of the world's land areas are covered by shallow overburden including glacial moraines in North America and Europe, jungle vegetation in South America, Africa and Asia, desert sand in many countries, glaciers and lakes. Undiscovered mineral deposits are likely to be present in target areas created by the impact of large meteorites similar to the Sudnury, Canada, nickel district where the energy of impact caused intrusion, metamophism, brecciation, hydrothermal activity and mineral deposition. At Sudbury a 10 km. diameter meteorite created a basin 62km. long, 30km. wide,and 15 km. wide and many nickel deposits along the crater rim. Some other mineral districts where proven impacts contributed to mineral deposition are:South African gold, lead-zinc in Sweden and industrial diamonds in Russia. Evidence for basins includes:negative gravity anomalies, Landsat and side-looking aerial radar images.

Published geophysical data indicates the possible presence of impact basins under cover. We have identified twelve areas in Canada and five areas in Australia where large negative gravity anomalies are known. In Brazil there are thirteen areas where the side-looking aerial radar images from the RADAM project indicate possible basins including one that is similar to the Sudbury district and one where geochemical base metal anomalies are present. In the Congo, Africa, a proven impact with associated copper deposits has a potential for new discoveries. In all these areas the outer rim of the basin may contain undiscovered mineral deposits.

Exploration for the deposits would initially require airborne or ground gravity surveys to confirm the existence of the basin. Detection of specific target areas could be accomplished by airborne magnetic and electromagnetic surveys followed by geophysical and geochemical investigations on the ground. Other areas where basins under cover are present could be located by airborne gravity or side-looking aerial radar surveys.