AS17-1819 (M)

Figure 36

 Click here for larger NASA image
 Click here for lunar chart showing location

The Haemus Mountains bound the southwestern edge of Mare Serenitatis and form the rim of the Serenitatis basin. They have a strongly lineated pattern that is most apparent in the lower left part of this stereoscopic view. (The width of the stereogram within this mosaic is shown by the bar across the bottom.) The trend of the linear pattern is radial to the Imbrium basin, the margin of which is about 250 km to the northwest of the edge of the picture. Carr (1966) described the mountains as composed mostly of ejecta from the Imbrium basin. The lineation may be due to shattering of the lunar crust by the Imbrium impact event, depositional fluting of the ejecta, gouges made by impacting debris from the Imbrium basin, or a combination of the three.

The prominent rilles in the upper part of the stereogram are grabens or fault troughs transecting both terra and mare surfaces. They are roughly concentric to the edge of the Serenitatis basin. The rilles become less distinct in the terrae, attesting to the easy destruction of surface features in terra material by mass wasting. Within Mare Serenitatis the rilles are partly flooded by the younger lavas that have filled the basin. A dark mantling material, named Sulpicius Gallus Formation, covers parts of the highland and mare surfaces alike. In the highlands the dark material has been removed from the tops of hills and steep slopes and reveals the underlying bright highland material. The dark mantle is conspicuous in the right center of the stereogram near the small kidney shaped crater (arrow). In this same crater and in small, young, rayed craters nearby, the Apollo 17 astronauts observed orange material. This suggests that the dark material here is similar to that sampled at the Apollo 17 landing site on the other side of the basin where orange material was found on
the rim of a young crater.   -B.K.L.

.