The rocks that make up the upper part of the oceanic crust, which occupies 70% of the area of ​​the earth, are basalt, which is a cold solidified lava that erupts from the mid-ocean ridge.Viable microbial species of rock may form the largest microbial ecosystem on Earth.In addition, the upper part of the crust of Mars and the upper part of the seafloor of the earth are similar, and it is expected that the analysis will provide a clue to the existence of extraterrestrial life.However, the basalt in the upper part of the oceanic crust was covered with sediment, and it was unclear whether it could survive due to the difficulty of sampling.

　This time, in a multilateral international cooperation project called the International Oceanic Drilling Program (IODP) led by Japan and the United States, the drillship Joydes Resolution provided by the United States will be used to 5697 million from the seabed at a depth of 1 m in the South Pacific Circumferential Region. A basalt core was obtained by excavating 121.8 m of the oceanic crust a year ago.

　As a result of investigating microminerals in the basalt core using the most advanced solid analysis method, seawater infiltrated and reacted along the cracks in the basalt to form layered silicate minerals.From the characteristics of this layered silicate mineral, it was also found that the reaction between iron and oxygen necessary for life activities is proceeding inside the rock.This revealed for the first time in the world that deep basalt in the crust is viable for 1 million years.

　Since the minerals whose formation was clarified in this survey are the same as the minerals that are universal under the Mars where the existence of water was found, it can be inferred from the upper part of the Earth's oceanic crust that Mars may survive. Indicated.

Paper information:[Scientific Reports] Iron-rich Smectite Formation in Subseafloor Basaltic Lava in Aged Oceanic Crust