We know that, due to the presences of granite on the Venusian surface that there were oceans on Venus. Now, how deep were they? It it possible, from the mass of the atmosphere, to determine how much water was on Venus before it evaporated away two billion years ago?

eh? granite does not require an ocean to form. it's igneous rock. it requires lava. venus has plenty.

 

also, i'd like to see your source that weve seen granite on venus. i can't find any reference even though it is likely to be present as there is lot of geological activity that leads to granite formation.

http://www.cbc.ca/technology/story/2009/07/14/venus-ocean-water-express.html

Thanks for the link VP. Interesting stuff, oceans on Venus long ago. Wow.