How impact craters create mountains

Asteroid created a habitat for microbes

The impact of an asteroid in the north of Mexico's Yucatán peninsula 66 million years ago ushered in the extinction of the great dinosaurs - but at the same time created a habitat for microbes. This is shown by the analysis of a submarine drill core by an international team of researchers. Accordingly, the impact formed an extensive hydrothermal system in the earth's crust. Such zones, in which hot water and gases circulate, are considered possible places for the origin of earthly life. Thus, asteroid impacts on the young earth could have promoted the origin and development of life, according to the scientists in the journal "Science Advances".

The 180-kilometer Chicxulub crater still bears witness to the massive asteroid impact that triggered the transition from the Cretaceous to the Paleogene. In recent years, researchers have found the first indications of the formation of a hydrothermal system after the impact. How long this area existed in the Chicxulub crater and to what depth it extended, however, has so far remained open. To solve the riddle, David Kring from the Lunar and Planetary Institute in Houston, USA, and his colleagues examined rock samples reaching a depth of 1,335 meters below the sea floor. "This is a unique opportunity to study the thermal and chemical changes in the earth's crust caused by an impact," said Kring.

The evaluation of the drill core shows that after the impact to a depth of 700 meters, an extensive hydrothermal system formed, in which temperatures of 300 to 400 degrees Celsius initially prevailed. Only after about two million years did the temperatures drop below 100 degrees Celsius. The scientists working with Kring estimate the total volume of the system to be around 140,000 cubic kilometers. It exceeds the hydrothermal system under the Yellowstone volcano by nine times. In addition, the drill core revealed numerous porous areas in the rock layers - ideal habitats for microbes.

Asteroid impacts can therefore give rise to long-lasting hydrothermal systems and thus create ideal zones for the evolution of life, Kring and his team conclude. In addition, such impacts were considerably more frequent on early Earth than in recent history. The systems created by impacts thus complement the long-known hydrothermal systems in the area of ​​volcanoes as a possible place of origin of earthly life.