Drilling deep to discover the secrets of the mantle

Project Mohole, in 1961, aimed to drill down into the floor of the Pacific ocean to collect the first-ever sample from the boundary between the Earth’s crust and mantle. This region is called the Mohorovičić discontinuity, or Moho for short. Although failing in its ultimate goal, the expedition was a major triumph for the scientific community, showing that drilling in deep waters in the ocean crust was possible. The project – and the technology it developed – led to an international programme of scientific ocean drilling that has lasted over 50 years.

Now scientists are trying to get ever closer to the Earth’s mantle, to finally answer questions about its composition, how earthquakes happen and whether we can learn from past climate change events.