A lunar density model consistent with topographic, gravitational, librational, and seismic data
A series of models of the lunar interior are derived from topographic, gravitational, librational, and seismic data. The librational parameters and low-degree gravity harmonics result primarily from surface height variations and only secondarily from lateral density variations. The moon departs from isostasy, even for the low-degree harmonics, with a maximum superisostatic stress of 200 bars under the major mascon basins. The mean crustal thicknesses under different physiographic regions are: mascons, 30–35 km; irregular maria, 50–60 km; and highlands, 90–110 km. A possible composition consistent with our model is an anorthositic crust, underlain by a predominantly forsterite upper mantle which grades into a refractory rich lower mantle surrounding a pyrrhotite core.
Additional Information© 1977 American Geophysical Union. Received May 5, 1976; revised October 1, 1976; accepted October 18, 1976. We would like to express appreciation to R. J. Phillips for support and valuable discussions during this investigation. This report represents one phase of research performed at both the Jet Propulsion Laboratory and the California Institute of Technology under NASA contract NAS 7-100. Division of Geological and Planetary Sciences, California Institute of Technology, contribution 2751.