Bangui magnetic anomaly

These results were confirmed and built upon by the high-altitude aeromagnetic surveys carried out by the US 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[need quotation to verify] at an altitude of 400 kilometres (250 mi).

[2][3] In 1982, Robert D. Regan and Bruce D. Marsh named the anomaly after the city located at its center.

[1] Its features include a Bouguer gravity anomaly of −120 mGal, a topographical surface feature shaped as a ring of 810 km (500 mi) diameter, rock features of Late Archean and Proterozoic periods in the central part of the anomaly, granulites, and charnockites rock formations supplemented by granites at the lower crust level, and greenstone belts, and metamorphosed basalts seen as rock exposures.

One theory points to a large igneous intrusion and the other to a meteorite impact in the Precambrian (before 540 Ma).