Early Habitability and Crustal Decarbonation of a Stagnant?Lid Venus

Little is known about the early evolution of Venus and a potential habitable period during first one billion years. In particular, it remains unclear whether or not plate tectonics an active carbonate-silicate cycle were present. presence liquid water but without tectonics, weathering would have been limited to freshly produced basaltic crust, with carbon restricted crust atmosphere. With evaporation surface water, cease. ongoing volcanism, carbonate sediments be buried sink downwards. Thereby, carbonates heat up until they become unstable depleted in carbonates. CO$_2$ supply atmosphere temperature rises further, depth below which decarbonation occurs decreases, causing release even more CO$_2$. We assess stagnant-lid by employing coupled interior-atmosphere model accounting for degassing, weathering, burial, crustal decarbonation. find that if initial conditions allow can keep planet 900 Myr, followed rapid depletion. For atmospheric exoplanets, we predict bimodal distribution, depending on these planets experienced runaway greenhouse their history. Planets high could associated depletion as consequence greenhouse, whereas low indicate silicate thereby climate.