Coronae of Mnemosyne Regio: Morphology and origin

摘要: Abstract Coronae are circular to elliptical structures 150–600 km across, characterized in Venera 15/16 and Arecibo radar images by an annulus of concentric ridges. The interiors the geologically complex, displaying volcanic flows, domes, radial, concentric, and/or obliquely trending ridges generally distinct from exterior. Mnemosyne Regio area, west Ishtar Terra, contains seven coronae, largest cluster coronae identified on Venus. On basis morphologic topographic characteristics region, we assess several possible models corona origin. Using cross-cutting stratigraphic relationships, have been able identify a sequence features events for this group determined that variety processes contribute origin evolution coronae. We find associated with diapirism or hotspots gravitational relaxation high topography most consistent observed morphology thus likely significant formation these observations following is outlined region: (1) regional tectonic activity; (2) localized uplift volcanism caused hotspots; (3) trough related relaxation, accompanied further (4) continued local flooding corona, annulus, trough. Differences between reflect variations amount significance geologic processes. other regions exhibit same overall as support similar majority