Coronae are volcanotectonic features that are unique to Venus and are interpreted to be small-scale upwellings. A model in which upwelling causes delamination at the edge of the plume head, along with deformation of a preexisting depleted mantle layer, produced the full range of topographic forms of coronae. If half of the coronae are active, delamination of the lower lithosphere could account for about IO percent of Venus’ heat loss, with another 15 percent due to upwelling. Delamination may occur in other geologic environments and could account for some of Venus’ heal loss "deficit.".