Deep bedrock mineral veins are microbial graveyards

Research in recent years has revealed that microorganisms inhabit fractured rocks of the continental and oceanic crust to depths of several kilometers, and that they have done so for millions of years. In a new study published in Communications Earth & Environment, an international team of researchers have collected mineral veins from more than 30 deep mines in the Swedish Precambrian basement to search for ancient life, and the signs are indeed plentiful and intriguing.