Early Water on Mars Hindered Subduction-Driven Plate Tectonics

Mars and Earth share many similarities in their early geological evolution, but only Earth developed active plate tectonics. One of the main unresolved phenomena in planetary science is understanding why plate tectonics, particularly subduction-driven plate tectonics, failed to develop on Mars. Here, I investigate the possibility of subduction initiation in early Mars with both dry and hydrated scenarios to see if crustal hydration could have prevented the initiation of subduction by affecting crustal density and mineral stability. This study investigates the buoyancy contrast between crust and mantle in Martian crusts of variable water content, using a combination of thermodynamic phase-equilibrium modeling and numerical calculations. Modeling was carried out across a range of pressure–temperature conditions relevant to crustal and upper mantle conditions in Martian environments, using bulk compositions including Yamato 980459, Gusev basalt, Zagami, and the average Martian crust. The models indicate that even small amounts of water, approximately 0.45–0.9 wt% H₂O, are sufficient to stabilize low-density water bearing mineral assemblages. The stabilization of these minerals greatly reduces the required density contrast for initiating subduction, implying that moderate crustal hydration would have prevented slab sinking. These findings indicate that water, usually thought to be a driver of subduction activity on Earth, may have been responsible for tectonic stagnation on Mars simply because its crust was too buoyant to subduct. The amount of hydration estimated in this work is in the range of altered oceanic crust from Earth tectonic systems. Also available geochemical and spectral evidence regarding ancient aqueous alteration and fluid-rock interactions on Mars supports my hypothesis. This implies that the hydrologically active history of earlier Mars might have paradoxically contributed to the long-term quiescence of its tectonics.

Author dc:creator

• Subhendu Pramanik (6883382)

• Planetary Science
• Geology

Statement dc:rights

• In Copyright
• Open Access after 2028-01-01

DOI dc:identifier

https://doi.org/10.25417/uic.31451815.v1

OAI identifier oai:identifier

oai:figshare.com:article/31451815