A satellite image of Gosses Bluff Crater located near the center of Australia. The crater is ... [+] believed to have been created by an asteroid impact around 142 million years ago.Getty ImagesResearchers from the Curtins School of Earth and Planetary Sciences and the Geological Survey of Western Australia announced the discovery of Earths oldest meteorite impact crater, located in the very heart of the Pilbara region of Western Australia. The crater formed more than 3.5 billion years ago, making it the oldest known by more than a billion years (the previous record holder being the Vredefort structure in South Africa).In an article published on The Conversation, the authors explain how they collected evidence in the field to prove the impact origin.The Pilbara region includes some of the oldest continental crust found on Earth, with rocks of the Pilbara Craton dating around 3,8 to 2,7 billion years.The researchers analyzed an unusual layer of rocks known as the Antarctic Creek Member (this part of Australia one of the hottest of the continent is also jokingly known as the North Pole Dome), which crops out on the flanks of a dome some 20 kilometers in diameter. The Antarctic Creek Member is only 20 meters or so in thickness, and mostly comprises volcaniclastic rocks and chert deposited around 3,47 billion years ago.However, this geological formation also contains older impact spherules droplets formed from molten rock thrown up during an impact. A geological survey identified also shatter cones. Shatter cones are cone-shaped branching structures and, in nature, can only form following a meteorite impact as shock waves shatter the bedrock.Example of shatter cones preserved in limestone.D.BressanBased on the size of the central dome, the authors estimated the outer crater is about 100 kilometers in diameter one of the larger impact craters found on Earth, but by far not the largest.The authors argue that the impact could also explain how some of the oldest continental crust on Earth formed. The rocks forming the outer shell of Earth are chemically very distinct from Earths mantle, and geologists are yet not sure what triggered this change around 4 to 3 billion years ago.As the impacts blasted up enormous volumes of material and melted the rocks around them, the mantle below produced thick "blobs" of hotter and less dense volcanic material rising upwards and evolving into continental crust.The study, "A Paleoarchaean impact crater in the Pilbara Craton, Western Australia," was published in the journal nature communications.