M. J. S. Belton G. Edward Danielson M. E. Davies D. E. Gault B. Hapke B. O'Leary R.G. Strom V. Suomi N. Trask B. C. Murray 1974 <p>The surface morphology and optical properties of Mercury resemble those of the moon in remarkable detail and record a very similar sequence of events. Chemical and mineralogical similarity of the outer layers of Mercury and the moon is implied; Mercury is probably a differentiated planet with a large iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of landforms has been found. Large-scale scarps and ridges unlike lunar or Martian features may reflect a unique period of planetary compression near the end of heavy bombardment by small planetesimals.</p> application/pdf 10.1126/science.185.4146.169 en American Association for the Advancement of Science Mercury's surface: Preliminary description and interpretation from Mariner 10 pictures article