That looks like it took a lot of work an complicated geology stuff to get right, but the results seem completely worth it! Your map looks really believable (to me with my untrained eyes). I'm quite inexperienced with cartography as a whole though so I'll leave the actual feedback to smarter people!

May I ask how you've been calculating the land area? I was doing rough estimates on my map with grids and counting the filled squares, so if you have a more accurate or easy way of doing it, I'm all ears!