martedì 21 agosto 2018

Gruithuisen highland domes (Termed Gruithuisen 1-3)

by Paolo Lazzarotti

Gruithuisen domes are known to have large diameters of up to 20 km, heights of more than 1000 m, steep flank slopes between 7° and 10°, and very high edifice volumes of several hundred km
The height of Gruithuisen γ (G1) was determined to 1740 m, the diameter amounts to 19 km, resulting in an average slope of 8.3°. The height of Gruithuisen δ and the Northwest Dome (G2 and G3) was determined to 1900 m and 1020 m respectively, with diameters of 27 km and 7.5 km, resulting in average slopes of 6.9° (G2) and 9.1° (G3). The edifice volumes assuming a parabolic shape of the domes is determined to 247km³, 544km³ and 43km³, respectively. These domes for their steep slope angles display a long shadow if imaged under oblique solar illumination.  The Gruithuisen highland domes form a separate spectral and morphometric group (class G) in the lunar domes classification scheme, due to their steep flank slopes, high volumes, and red spectral signatures, giving rise to the assumption that they have been formed by lava of significantly different composition erupted over a long period of time. Their formation is determined from highly silicic non-mare lavas.