An investigation of the depth of excavation and thickness of basalt fill for the lunar mascon basins

Abstract

In a previous paper (Mullis 1991), a model for the formation of the Imbrium gravity anomaly was described, which yielded estimates of both the maximum depth of excavation of the basin and depth of basalt fill in the resulting topographic depression. This model has now been extended to the Serenitatis, Humorum, Crisium, Nectaris and Orientale basins. In each case, depth/diameter ratios for the original excavation close to 0.08 have been determined. This is much shallower than would be expected from extrapolation of depth/diameter ratios for small fresh lunar craters, and would suggest that none of the impact structures considered excavated below the level of the crust/mantle boundary. Mare basalt thicknesses for the structures considered range from 1.8km for Orientale to 4.9km for Serenitatis. Copyright © 1992, Wiley Blackwell. All rights reserved