Volcanic structures within Niger and Dao Valles, Mars, and implications for outflow channel evolution and Hellas Basin rim development

Abstract

<div lang="en" class="abs"><p class="abs_header">Abstract</p><p>Outflow channel formation on the eastern Hellas rim region is traditionally thought to have been triggered by activity phases of the nearby volcanoes Hadriacus and Tyrrhenus Montes: As a result of volcanic heating subsurface volatiles were mobilized. It is, however, under debate, whether eastern Hellas volcanism was in fact more extensive, and if there were volcanic centers separate from the identified central volcanoes. This work describes previously unrecognized structures in the Niger‐Dao Valles outflow channel complex. We interpret them as volcanic edifices: cones, a shield, and a caldera. The structures provide evidence of an additional volcanic center within the valles and indicate volcanic activity both prior to and following the formation of the outflow events. They expand the extent, type, and duration of volcanic activity in the Circum‐Hellas Volcanic Province and provide new information on interaction between volcanism and fluvial activity.</p></div>