Apennine region

Huxley domes (termed Hexley 1-3)

By Mike Wirths

by Carmelo Zannelli

Dome	Longitude	Latitude	Diameter [km]	Heigth [m]	Slope[°]
Huxley 1 Huxley 2 Huxley 3	-3.68° -4.42° -3.68°	21.26° 20.28° 21.26°	14 ± 0.5 7.5x9.6± 0.5  31.5x23 ± 1	200 ± 20 50 ± 5 85 ± 10	1.64 ± 0.2     0.64 ± 0.06     0.37± 0.04

The oldest lavas in this region are probably those of the lighter albedo plains units inside the main Imbrium ring, called the Apennine Bench Formation. The dome Huxley 1 (Hux1) has a diameter of 14 km. The height amounts to 200 ± 20 m resulting in flank slopes of 1.64° ± 0.2°. Based on rheologic modelling Hux1 formed from lava of viscosities of 1.8 x 10⁶ over a period of time of 4.1 years. It is a C₂ dome in the classification scheme of effusive lunar domes.

The heights of the domes Hux2 and Hux3 were determined to 50 ± 5 m and 85 ± 10 m, resulting in flank slopes of 0.64° and 0.37°, respectively. Hux 2, of elongated shape (circularity < 0.8), has two small prominences, likely floor ridges which were embayed by the dome, as indicated by their alignment with ridges to the north. Moreover, its surface is inclined from the northwest toward the southeast direction. The dome Hux3, of elongated shape, is associated with some short linear and curvilinear rilles and has a sinuous rille on its surface, the latter clearly indicating an effusion of lava. Under the assumption of an intrusive origin, and according with the results of the laccolith modelling, the candidate intrusive dome Hux3 belongs to class In₁, while Hux2 is a typical representative of class In₂.