By Erin Wayman
Meteorites smacking into the early Earth could have created warm, watery environments favorable to primordial life. A new study of an impact crater in Finland suggests that such hydrothermal activity could have lasted up to 1.6 million years — at least 10 times longer than theory suggested, providing plenty of time for life to emerge and spread.
Ancient impact craters on Mars were probably also home to hydrothermal activity, making them good places to search for signs of life, the team reports online February 19 in Geochimica et Cosmochimica Acta.
The work is “quite exciting,” says Gordon Osinski, a planetary geologist at the University of Western Ontario in Canada. “One of the big unknowns has been how long do these hydrothermal systems last.”
Because hydrothermal systems house life’s most ancient lineages, many biologists think that the first organisms arose there. Volcanoes drive most hydrothermal activity today, such as the hot springs and geysers of Yellowstone. But when life evolved about 3.8 billion years ago, frequent impacts pummeling the planet were the largest source of hydrothermal activity. Energy from such events melted rock and heated water circulating through the Earth’s crust. These hydrothermal environments would have been cozy, protective habitats where life could have emerged, or at least thrived and evolved, Osinski says.