The Miralga impact structure is an impact structure in the Pilbara Craton of Western Australia. With an initially estimated age of around 3.47 billion years dating to the Paleoarchean, it has been suggested to be the oldest known impact structure on Earth by over a billion years and the only one known from the Archean.
The structure is found in the East Pilbara Terrane, one of the oldest parts of the Pilbara Craton. The structure lies on a geological dome called the North Pole Dome which was initially suggested to represent the central uplift of the structure. Evidence of the impact is shatter cones found in the Antarctic Creek Member, a 20 metres (66 ft) thick layer of sedimentary rock including "felsic to mafic volcaniclastic rocks, chert, argillite, arenite and jaspilite intruded by dolerite", sandwiched between overlying and underlying volcanic rocks of the Mount Ada Basalt Basalt, which is 2–3 kilometres (1.2–1.9 mi) thick.
