Information resources at the LGS

A major programme, funded by the US Agency for International Development (USAID) and the Liberian Ministry of Lands, Mines and Energy, was carried out by the United States Geological Survey (USGS) and the Liberian Geological Survey (LGS) between 1965 and 1972.

Aeromagnetic and total-count gamma radiation surveys were carried out in 1967–1968 over the entire country. A total of 140 000 km was flown, mostly along north–south lines, 0.8 km apart on land and 4 km apart over the continental shelf. The flight altitude was 150 m above terrain.

Geological maps for each of the ten quadrangles covering Liberia were compiled at a scale of 1:250 000 from interpretation of the airborne geophysical data and aerial photos, supplemented by field traverses along the major river courses. Each map is accompanied by a short descriptive report. The maps and reports are available from the Liberian Geological Documentation Centre (LGDC) of the LGS.

In 2007, the geological, geophysical and mineral-occurrence data were compiled into digital form and released as a series of four national maps at a scale of 1:340 000. Now stored within the Liberian Minerals Information System (LMIS) this digital compilation provides a comprehensive and readily accessible overview of Liberia's solid geology and known mineral occurrences, and is an excellent basis for the identification of targets prospective for a wide range of metallic and non-metallic mineral commodities.

Further processing of the legacy aeromagnetic data using modern software also has great potential for providing considerable additional geological detail and thus highlight new exploration targets. Additionally, in early 2016, the People's Republic of China began a combined geophysical and geochemical data-collection program throughout the country. Regional geophysical (1:100 000-scale aeromagnetic, 1 km line spacing) and low-density geochemical (1:1 000 000-scale, one sample point/100 km2) data will be collected for the whole country. Higher-resolution geophysical (1:25 000-scale aeromagnetic, 0.25 km line spacing) and geochemical (1:100 000-scale, one geochemical sample point/km2) data will also be collected for the Lofa district. The data and interpreted results from this, the first systematic data collection program in Liberia for 45 years, are scheduled for delivery in the summer of 2018.