Strong evidence of plate tectonics also supports the existence of early Mars ocean.
See for example here:
Plate Tectonics: The Mechanism.
http://www.ucmp.berkeley.edu/geology/tecmech.html
Bob Clark
Space/Science » in reply to New Map Provides More Evidence Mars Once Like Earth
See for example here:
Plate Tectonics: The Mechanism.
http://www.ucmp.berkeley.edu/geology/tecmech.html
Bob Clark