Question: what was the most complex rock you've ever studied and what made it so complicated?

Vincent Monchal answered on 25 Nov 2022:

I studied a rock that was 3.2 billion years old. It was a metamorphic rock called granulite and composed of various minerals. The facts that it was really old and composed of various minerals make it really complicated to study because you need to understand what that rock have experienced, and in 3.2 billion years it could have experience a lot of things ! You also need to understand what mineral have crystalize first so you can retrace the history of that rock, more there is different mineral, more complex is the history.