An alternative mechanism for recent volcanism on Mars

Abstract

Images of the Martian surface indicate that volcanism is a recent process on Mars with ages of the youngest lava flows of about 2 Ma. Interestingly, these young lava flows are confined to the large, old volcanic centers of Tharsis and Elysium, which exhibit a thickened crust compared to surrounding areas. The origin of the volcanic centers but also their longstanding volcanic activity is often explained by strong mantle plumes arising from the core-mantle boundary. However, their existence and sustainment during the last few billion years is uncertain under Martian conditions. Alternatively, the thermal insulation by the crust could cause the longstanding volcanic activity. We show that a locally thickened crust, which has a lower thermal conductivity and is enriched in radioactive heat sources in comparison to the mantle, leads to significant lateral temperature variations in the upper mantle sufficient to generate partial melt even in the present Martian mantle.