CORONA FORMATION AND HEAT-LOSS ON VENUS BY COUPLED UPWELLING AND DELAMINATION

Coronae are volcanotectonic features that are unique to Venus and are interpreted to be small-scale upwellings. A model in which upwelling c auses delamination at the edge of the plume head, along with deformati on of a preexisting depleted mantle layer, produced the full range of topographic forms of coronae. If half of the coronae are active, delam ination of the lower lithosphere could account for about IO percent of Venus' heat loss, with another 15 percent due to upwelling. Delaminat ion may occur in other geologic environments and could account for som e of Venus' heal loss ''deficit.''.