World's Oldest Rocks Found, with Signs of Life

Earth's most ancient rocks, with an age of 4.28 billion years, have been found on the shore of Hudson Bay, Canada. The sample of Nuvvuagittuq greenstone is 250 million years older than any rocks known.

It may even hold evidence of activity by ancient life forms. If so, it would be the earliest evidence of life on Earth.

The rocks contain geological structures which might only have been formed if early life forms were present on the planet. The material displays a banded iron formation - fine ribbon-like bands of alternating magnetite and quartz. This feature is typical of rock precipitated in deep sea hydrothermal vents - which have been touted as potential habitats for early life on Earth. These ribbons could imply that that 4.3 billion years ago Earth had an ocean with hydrothermal circulation. Some scientists believe that to make precipitation work, you also need bacteria. If true, then this would be the oldest evidence of life.

Original article here.