A team of researchers was able to use crime scene investigation methods to determine asteroid impact locations on Earth. It is quite challenging to estimate the number asteroids that have struck Earth. The majority of craters have been eroded and eliminated as our planet evolved. Over the course of the last billion years, Earth has been struck by asteroids on multiple occasions. Some of them altered the path that history would take.
Sikhote-Alin is the youngest crater-strewn landscape on our planet. It was formed by an asteroid impact in far-eastern Russia in 1947. There are numerous examples of such asteroid strikes. In the past 11,650 years, just 30 percent of Holocene asteroid impact craters have been found. Preparing for this natural hazard requires analyzing the frequency of these tiny impacts in the past and how they affected the environment.
Researchers at the University of Exeter have excavated trenches in the rims of four craters – Kaali Main and Kaali 2/8 in Estonia, Morasko in Poland, and Whitecourt in Canada. These asteroid craters developed thousands of years apart on two different continents. By analyzing the charcoal surrounding the craters and comparing it to charcoal produced by wildfires, researchers were able to determine the origin of these small craters. Dr. Jüri Plado and Dr. Argo Jeleht from the Institute of Ecology and Earth Sciences at the University of Tartu observed,“Surprisingly, in all of these locations we discovered the same thing: mm to cm sized pieces of charcoal intermixed with material ejected during the formation of the crater and located in the same location.”
Determining Future Asteroid Impact Zones
Dr. Ania Losiak, the lead author of this study from the Institute of Geological Sciences, Polish Academy of Sciences, and the University of Exeter, stated,“The properties of organisms turned into charcoal reflect the conditions in which they were killed.” The impact charcoal appears to have been formed at much lower temperatures than wildfire charcoal, since they lack sections that were created while in direct contact with the flame. Moreover, they are all very similar to one another, whereas in a fire it is common to find heavily charred wood next to branches with minimal damage. “This is definitely not what we expected when we started this study: we think that impact charcoals were formed when fragments of trees shattered by the impact were intermixed with local material ejected from the crater,” Dr Losiak said in a press release.
The scientists treated the charcoal from the asteroid craters as evidence from a crime scene. They discovered that the charcoal was not at all similar to that produced by wildfires. The incoming space debris shattered and burnt tree branches. Later on, it was combined with the dirt and other materials dug from the craters’ rims. This study also examines the environmental effects of minor impact craters. In the future, the hope is that scientists will be able to determine the size and type of evacuation zone needed for large asteroids headed for Earth just a few weeks before impact.
Source: University of Exeter, Eureka Alert