Small Volcanic Vents and Vent Fields on Venus
Shield fields have been considered to be a distinct type of volcanic center on Venus, arising from melt areas of limited extent, possibly deep magma sources, and low magma rates delivered to the surface; this is essentially the current interpretation of terrestrial volcanic fields with clustered monogenetic vents. Globally, shield fields occur that are stratigraphically older, stratigraphically younger, and apparently contemporaneous with, the surrounding plains. It is probable that the formation of shield fields has occurred locally throughout Venus' geologic history.
Shield plains may be analogous to terrestrial oceanic seamounts; volcanism associated with a widespread melt source and relatively shallow magma sources. The unit is interpreted as formed by the eruption of multiple small shields and associated flows over some finite geologic time interval; an interval that may have been geologically short or long. In its type locality in Akkruva Colles and in many other locations where it has been mapped, the unit occurs in a distinct and consistent stratigraphic position. Shield plains are evidence for a unique interval and mechanism of plains formation over many areas of the surface of Venus.