Cleopatra (crater)

A steep-walled, winding channel a few kilometers wide (Anuket Vallis) breaks through the rough terrain surrounding the crater rim.

[5][7] A volcanic origin initially was supported due to non-impact geologic aspects, such as having a low rim, a surrounding plains-forming unit, and a non-concentric nature of its inner basin, as well as its proximity to Maxwell Montes.

[12] Using photogeologic analysis, the floor of the crater has a shallow central depression resulting from subsidence of uplifted mantle material from below due to "viscous relaxation".

[14] This was found in Venusian craters larger than 70 km in diameter by using altimetry data which shows surfaces with different elevations from the Magellan mission.

[6] This results in the melting of the lower levels of the thickened crust and potential magmatic activity, volcanism, and caldera formation at the surface.

[6] The following evidence from Schaber et al.[11] was the leading explanation for a volcanic origin for twelve years until Magellan imagery was returned in the early 1990s.

Zoomed in view extrapolated from Magellan spacecraft imagery of Cleopatra patera, eastern flank of Maxwell Montes on Ishtar Terra , Venus, Feb 5, 1994.
patera is a complex impact crater with a central peak . Cleopatra patera has an asymmetrical central peak, as opposed to the image. Complex craters have terraces, multiple rings , and a central peak. Cleopatra patera is a double ring impact crater. This image is modified from David Kring, NASA University of Arizona Space Imagery Center, 2006.
Impact craters differ from a complex impact crater because they lack a central peak, have a small-bowl shape and smooth walled. Before the Magellan mission to Venus in 1994, controversies about the origin of Cleopatra patera existed due to the asymmetric shape of the floor of the crater, which appeared smooth. This image is modified from David Kring, NASA University of Arizona Space Imagery Center, 2006.
Volcanotectonic interpretation of ring structures of Cleopatra Patera as interpreted from Peterfreund et al.