re: Hematite
I originally thought this crater on Mars was an eroded dome, but I have a new theory that I think is what happened.
In my new theory, this is actually an impact crater. Over time, sedimentary layer after layer filled the inside of the crater, making it smaller in depth and diameter over time. Eventually, the crater filled in. Today, the top portion of the crater has been eroded off, exposing the layering.