MAPPING THE NESTED CALDERA COMPLEX ON THE SUMMIT OF IDUNN MONS, VENUS, AND ITS IMPLICATION FOR THE VOLCANIC HISTORY OF THE EDIFICE

Idunn Mons (46.5°S, 215°E) is a ~200 km diameter large shield volcano that rises ~3 km above the surrounding terrain on the eastern edge of Imdr Regio on Venus. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express detected relatively high values of nightside thermal emissivity near 1 μm wavelength on flows on Idunn’s eastern flank (Smrekar et al., 2010), suggesting this volcano may have been recently active [Smrekar et al., 2010; D’Incecco et al., 2017)]. This makes Idunn Mons an intriguing landform to examine in any future mission to Venus. To that end, we have focused on mapping the nested caldera complex at the summit of this volcano. Specifically, the summit hosts about 7 overlapping calderas ranging in diameter from about 3km to 6km. The calderas show an overall younging to SW portion of the summit suggesting possible lateral migration of a magma body in that direction. Around the rim are radar-dark areas, possibly indicating a smooth lava flow, which may have originated at one of the small pit crater chains that trend NW/SE. That would make it very comparable to terrestrial and Martian analogues. Understanding the processes involved here will help with future investigations and missions to Venus.