Researchers from the Australian National University’s School of Archaeology and Anthropology have reported that an asteroid which broke just seconds before hitting Earth formed a 400 kilometre (248 miles) impact zone in Central Australia. This crater was created millions of years ago. Geophysicists have found the two scars from the impacts, which is the most extensive asteroid impact area ever discovered on Earth. They are located deep beneath the surface. These findings were published in the scientific journal Tectonophysics. Andrew Glikson examines a suevite sample. This is a rock that has partially melted material from an impact. The impact zone was found in an area close to the border of South Australia, Queensland, and the Northern Territory. It was discovered by Dr. Andrew Glikson during drilling for a geothermal project. Two asteroids 10 kilometers wide Dr. Glikson stated: “The two asteroids should each have been more 10 kilometers across – this would have been curtains to many life forms on the planet at that time.” Scientists believe the discovery of ancient, violent impacts may lead them to new ideas about the Earth’s history. Dr. Glikson stated that large impacts such as these could have played a much greater role in Earth’s history than was previously believed. Geophysicists aren’t sure exactly when the impacts occurred. Although the rocks are 300 and 600 millions years old, there is not evidence that other meteorite impacts left any type of mark. The asteroid split in two meteors when it entered Earth’s atmosphere. A large impact that took place 66 millions of years ago caused a plume of ash to rise, which is found in the sediment of rocks all over our planet. According to scientists, the plume may have caused significant extinctions of many species of dinosaurs and other life forms on Earth. Scientists explained that there is no evidence for an ash plume. However, a similar layer was not found in sediments back 300 millions years. Dr. Glikson stated that it was a mystery as to why there isn’t an event comparable to these collisions. The impact may be more than 300 millions years old, I suspect.” Evidence of impacts was discovered by a geothermal research team while drilling two kilometers into Earth’s crust. The drill core contained traces of rock that was turned to glass from the extreme high pressure and temperature caused by an impact. The deep crust of the Earth revealed deep bulges rich in iron and magnesium, which corresponded to Earth’s mantle. Dr. Glikson stated that there are “two huge deep domes” in the crust. These are formed when the Earth’s crust bounces off the impacts and brings up rocks from the earth mantle. These impacts extend into the Earth’s crust which in this region is about 30 km thick. Citation: Geophysical anomalies, quartz deformation and Warburton West structure in central Australia. A.Y. Glikson, .J. Meixner, B. Radke, I.T. Uysal E. Saygin J. Vickers, and T.P. Mernagh. Tectonophysics, Volume 643, Published March 7, 2015.
A giant 400 km-wide asteroid impact area was discovered in Australia
