A subset of Pogo satellite magnetometer data has been formed that is suitable for analysis of crustal magnetic anomalies. Through the use of a thirteenth‐order field model fit to these data, magnetic residuals have been calculated over the world to latitude limits of ±50°. These residuals, averaged over 1° latitude‐longitude blocks, represent a detailed global magnetic anomaly map derived solely from satellite data. The occurrence of these anomalies on all individual satellite passes independent of local time and their decay as altitude increases imply a definite internal origin. Their wavelength structure and their correlation with known tectonic features further suggest that these anomalies are primarily of geologic origin and have their sources in the lithosphere.

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Satellite magnetometer data have revealed a long‐wave length magnetic anomaly in the vicinity of Bangui, Central African Republic. Substantiation of the anomaly has been made through analysis of air and ground magnetic surveys. A correlative gravity anomaly has also been observed in ground gravity data. The anomaly, in an area of highly metamorphosed Precambrian rocks, does not correlate with any surficial features but is definitely crustal in origin. An interpretation consistent with all available geophysical and geological data is that the anomaly could be the result of an early intrusion into the crustal rocks of this region, followed by subsidence and deformation.

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The residual gravity anomaly associated with Meteor Crater, Arizona, which attains a maximum negative amplitude of 0.6 mGal, is attributed to a breccia lens 225 m thick beneath the center of the apparent crater floor. The lens is in general radially symmetric with only minor irregularities, particularly in the southern half of the crater. No definitive evidence was found for a dense meteoritic body in the crater vicinity. The crater is surrounded by a negatibe gravity anomaly due to low-density rim debris, uplifted and fractured bedrock, and possibly an underlying fractured zone extending about one crater radius out from the rim crest and dipping into the crater. A magnetic minimum with a maximum negative amplitude of approximately 20 3' is coincident with Meteor Crater. The most probable source of this anomaly is the alteration, by impact, of the remanent magnetization of the underlying formations, particularly the Supai, within and beneath the breccia lens. Looeik, 1965]. The distinctive geophysical characteristic of these craters is a negative gravity anomaly attributed to a mass deficiency reflecting the brecciation and fracturing of the rocks in the vicinity of the craters. The U.S. Geological Survey (USGS) has conducted a program of geological and geophysical investigations of representative terrestrial craters to supplement the existing body of knowledge on craters. As part of this program, an intensive geophysical study has been made of Meteor Crater, Arizona. This crater is particularly suitable for investigation Copyright (D 1975 by the American Geophysical Union.because it is structurally simple, young, well preserved, and occurs in horizontal sedimentary rocks. Ackermann et al. [1975] have detailed the seismic investigation, and the results of the gravity and magnetic studies are presented here. PREVIOUS INVESTIGATIONS