Evidence for Present Day Volcanism on Venus: A Case Study of Idunn Mons

Idunn Mons in Imdr Regio on Venus is perhaps one of the best studied volcanoes on Venus in part due to having both radar and night-time emissivity data of the region [1-3]. Smrekar et al. [1] first presented night-time emissivity data of Idunn Mons from the VIRTIS instrument on Venus Express, which showed that some lava flows have high emissivity consistent with unweathered basalt. Smrekar et al. [1], based on known weathering rates at that time, suggested that the lava flows were less than 2.5 million years old and possible as young as 250,000 years old. However, recent experimental work has shown that basaltic rocks and associated minerals in contact with the Venusian caustic atmosphere would react quickly to produce rinds of alteration materials coating the surface and obscure emissivity signatures of igneous minerals within a few to ~10,000 years [4-9]. These new experimentally derived weathering and oxidation rates were used to suggest that lava flows at Idunn Mons with unweathered signatures are quite young and Idunn Mons may be volcanically active today [4, 8]. Independent geologic mapping and related stratigraphic reconstruction over the study area is consistent with the experimental results [2, 10]. Considering all the available evidence, we have taken a comprehensive approach combining these recent experimental results with previous orbital night-time emissivity, as well as atmospheric measurements, to constrain the evolution of Idunn Mons [3,10]. Our results suggest that Idunn Mons is both volcanically and tectonically active today, and that volcanism and tectonic activity are likely related [11]. Venus being volcanically active has been suggested at other volcanic centers, as well [e.g. 12-17]. Therefore, we use Idunn Mons specifically as a case study of a potentially active volcano that may be detectable by the upcoming fleet of missions that will be arriving at Venus in the next decade.