Outback Deep Impact is Largest Asteroid Crater Ever Discovered on Earth

""The largest asteroid impact zone in the world has been discovered in Australia. A pair of markings are each measured to be at least 125 miles in diameter.

Analysis reveals the geological feature was formed by a massive asteroid more than 300 million years in the past, which likely split into two pieces from atmospheric friction before striking the ground.

The impact was responsible for a widespread extinction that vastly altered the biological makeup of the planet. However, no extinction event can be definitively tied to this collision, and there is no distinct geological layer in the strata of the Earth that provides a means of definitively dating the event. When a separate asteroid impact 66 million years ago ended the age of the dinosaurs, the blast sent a layer of iridium around the planet that was easily detected by geologists.

"The two asteroids must each have been over 10 kilometers (about 6 miles) across - it would have been curtains for many life species on the planet at the time. Large impacts like these may have had a far more significant role in the Earth's evolution than previously thought," said Andrew Glikson from the Australian National University's School of Archaeology and Anthropology.

The first of these markings was discovered in 2010, and researchers at the time declared it to be the third-largest meteor basin in the world. It is possible that the impact occurred more than 300 million years ago, researchers theorize. Dating of the basin is uncertain due to the nature of the rocks in the area, which are between 300 and 600 million years old.

A geothermal research project drilled over 1.25 miles under the surface of Warburton Basin in Central Australia, revealing a region where rock melted due to tremendous heat and pressure, forming glass. This material may have been created by a tremendous impact with an asteroid, investigators determined.

The crust of the Earth in this area, also known as the Alice Springs region, is nearly 19 miles thick. Magnetic modeling revealed the presence of two large domes in the crust, consistent with features that would be formed if the upper layer of the planet rebounded following a major impact.""

http://www.techtimes.com/articles/41660/20150323/largest-meteorite-crater-discovered-australian-outback-what-really-happened.htm

New Empirical Evidence Suggests Fire Storm Not Solely Responsible for Mass Earth Extinctions of Plant and Animal Species 65 Millions Years Ago

The asteroid that wiped out the dinosaurs set off an intense heat wave that briefly boiled the Earth’s atmosphere – but it didn’t burn off all the plants.

Humanity has not been unlucky enough to observe at first hand the effects of a large impact, so to investigate whether a massive asteroid would spark off a global wildfire we had to turn to the laboratory. We have modelled, for the first time, the heat generated by the impact and what it meant for the planet’s plants. Our research is published in the Journal of the Geological Society.

This all happened 65m years ago at the end of the Cretaceous period, when dinosaurs still roamed the earth. Suddenly, between 60 and 80% of all living species became extinct. Until the 1980s, this catastrophic loss of life was a mystery, but then scientists found a clue – traces of the element iridium in rocks of this age. Iridium generally falls to Earth with extraterrestrial objects. This suggested a massive asteroid collided with the planet and that this could be responsible for the mass extinction.

Ten years later, scientists found the 65m year-old, 180km wide, Chicxulub crater on the Yucatan Peninsula in Mexico, which finally provided the smoking gun that could explain the apparent chaos at the end of the Cretaceous era. A crater that wide suggests that an asteroid or comet approximately 10km wide hit the Earth.

The impact would have released a huge amount of energy – equivalent to more than a billion Hiroshima bombs. The asteroid itself was vaporised as it smashed into the Earth and in doing so vaporised and blasted out particles of the rock that it hit.

A huge glowing ball of hot rock and vapour rushed up from the impact site at huge speeds, ejecting it way above the atmosphere up into space. As it hit the cold of space it decelerated, cooled and rained back through the atmosphere, re-solidifying and forming tiny droplets of rock known as “spherules”.

Find Out More:

http://www.rawstory.com/rs/2015/01/revealed-asteroid-that-killed-the-dinosaurs-boiled-the-earths-atmosphere/