The Stanford geologists at Generation Anthropocene are my new favorite people. They recently assembled a presentation that extrapolates from clues in the books how the continent of Westeros in A Song of Ice and Fire / Game of Thrones came to be formed, from the salt flats of Dorne to the granite of Winterfell, and it is an exceptionally clever work that breathes new color into George R. R. Martin’s world.
They also nail down precisely how big the planet is—an attempt I made myself last year with less precise methods—figure out where the tectonic plates are, find missing volcanoes, and discover a period in the planet’s history where winter thoroughly won the fight.
Check out the full thing here. Don't fret over not knowing anything about geology. The writing in the presentation presents everything very clearly and concisely, allowing anyone to follow the progression of Westeros from southern hemispheric lump to its jagged current-day self. Here’s hoping they publish an update that folds Essos and the Known World into the mix!