Orcus Patera

So I came across the following quote, about a mysterious crater on Mars. No one knows exactly how it was formed:“Orcus Patera is an enigmatic elliptical depression near Mars’s equator, in the eastern hemisphere of the planet. Located between the volcanoes of Elysium Mons and Olympus Mons, its formation remains a mystery. Often overlooked, this well-defined depression extends approximately 380 km