Parga and Hecate Chasmata, Venus: Structure, volcanism and models of formation

Linear zones of deformation in the equatorial zone of Venus characterized by extension and volcanism have previously been identified in Pioneer Venus and Arecibo data. Two of these zones, Parga and Hecate Chasmata, are seen in Magellan data to be characterized by systems of fractures along which lie numerous coronae and corona-like features. The relationship between tectonic deformation, corona formation, and volcanism in Parga and Hecate Chasmata is examined using Magellan image and altimetry data. We examine several hypotheses for the origin of these zones, including extension and upwelling and delamination or subduction. In a companion abstract, we examine a section of Hecate Chasma in detail.