Bangui magnetic anomaly

The Bangui magnetic anomaly is a local variation in the Earth's magnetic field centered at Bangui, Central African Republic. The magnetic anomaly is roughly elliptical, about 700 km × 1,000 km (430 mi × 620 mi), and covers most of the country, making it one of the "largest and most intense crustal magnetic anomalies on the African continent". The anomaly was discovered in the late 1950s, explored in the 1970s, and named in 1982. Its origin remains unclear.

History

In 1962, Raymond Godivier and Lucien Le Donche reported on a magnetic anomaly in the Central African Republic, which they identified by analyzing their surface magnetic activity data of 1956. These results were confirmed and built upon by the high-altitude aeromagnetic surveys carried out by the United States Naval Oceanographic Office, as well as by the satellite measurements conducted in 1964 with Cosmos 49 and in the 1970s with the Orbiting Geophysical Observatory at 350–500 kilometres (220–310 mi) altitudes. This data was combined in 1973 and yielded a spatial map of Earth's magnetic field, which was then updated after the launch of the Magsat satellite with an accuracy of 15 nT at an altitude of 400 kilometres (250 mi). In 1982, Robert D. Regan and Bruce D. Marsh named the anomaly after the city located at its center. The anomaly is sometimes called the Bangui negative anomaly, owing to its negative peak-to-trough difference, and is compared with the positive anomalies observed at the Benue Trough and Congo Basin where Lower Cambrian geological formations are exposed.

Salient features

The Bangui anomaly is bounded to the south by the Walvis Ridge, the north by the Cameroon–St.