Unusual prehistoric world discovered in southern desert

A detailed look at what life at the beginning of the earthcan be seen at an altitude of 12,000 meters above sea level on the border of Chile and Argentina in the so-called Puna de Atacama, in the Ojos del Salado volcano.

University of Colorado Boulder geologist Brian Hynek has helped document what may be a unique type of ecosystem on Earth and a possible window into the early stages of life on this planet 3.5 billion years ago and even life on ancient Mars, even calling it part of the world – “foreign territory”

These are Andean lagoons surrounded by vast salt flats and containing stromatolites, or complex microbial communities, that form giant rock mounds as they grow, a bit like corals building a reef, millimeter by millimeter.

The most incredible thing about the formation of these lagoons is that they existed during a period of Earth’s history called the Early Archean, when there was almost no oxygen in the atmosphere.

“This lagoon may be one of the best modern examples of the first signs of life on Earth,” said Hynek, a professor in the Laboratory of Atmospheric and Space Physics (LASP) and the Department of Geological Sciences. “It’s unlike anything I’ve ever seen, or anything any scientist has ever seen.”

Stromatolites in the Atacama lagoons closely resembled the formation of these layers in prehistoric times.

Its rock layers were built primarily from gypsum, a mineral commonly found in many stromatolite fossils but absent from almost all modern stromatolite specimens. Biologically, they consisted of an outer layer of photosynthetic microbes called cyanobacteria and a pink core rich in archaea, single-celled organisms often found in Earth’s extreme environments.

“We think these mounds are actually growing from microbes, which is what happened with the older ones,” Hynek said.

Communities could also provide scientists with unprecedented information about how life may have originated in Marswhich looked like the Earth billions of years ago.

“If life ever evolved to the level of fossils on Mars, this would be the case,” Hynek said. “Understanding these modern communities on Earth could tell us what to look for when we look for similar features in Martian rocks.”