Science, Vol. 284, Iss. 5415, p. 790-793, Apr 1999.
Figure 3. Map showing the distribution of crustal magnetic field sources superimposed on a map showing the distribution of craters greater than 15 km in diameter (8) and the dichotomy boundary (solid line). The spacecraft tracks below 200 km altitude have been projected onto the surface as light green thick lines to illustrate the orbital coverage. The thickness of the subsatellite tracks has been chosen to approximate the equivalent "pixel" size for observations as discussed in the text. The measured radial (vertical) component of the magnetic field associated with the crustal sources is illustrated using a color scale that reveals the location of significant magnetic sources detected regardless of intensity. Note the high correlation between the region where magnetic crustal sources appear and high crater densities (ancient terrain) and the absence of magnetic imprints within the Hellas, Argyre, and Isidis impact basins. No magnetic signatures have been found over Elysium, Olympus Mons, or Tharsis Montes.