Morphologic and gravimetric investigations of Bell and Eisila regiones on Venus

Crustal density models are calculated for Bell and Eisila Regiones on Venus, and results are compared with the morphology determined from the Pioneer Venus Orbiter and the Venera 15 and 16 missions. Two groups of density models are calculated under the assumption of Airy isostatic compensation of the topography: (1) a group with global total compensation assumed along the profile, and regional partial compensation assumed for Bell and Eisila Regiones; and (2) a group with total compensation for the whole profile and a regional very large depth of compensation for Bell and Eisila Regiones. The volcanic-tectonic uplift found at Beta, Bell, and Atla Regiones provides support for the important role of hot spot volcanism in Venusian tectonics. (R.R.)