Ocean drilling

Scientific certainties and uncertainties

Living on land as we do, it is easy to forget that oceans cover more than 70% of the Earth's surface. Some say planet Earth should be called planet Ocean.

The oceans hold vital information about our planet's past and present and therefore its future. Over the past 40 years, scientists have drilled over 2,000 holes into sediments and rocks under the oceans to learn what makes up the Earth.

That may seem like a lot of holes, but when you consider that the British Geological Survey's borehole database contains records for over 800,000 drill holes just for the UK, you get an idea of how much of the ocean floor remains unexplored.

Trying to understand the deep ocean floors from those 2,000 holes is a bit like inferring the geology of the British Isles by looking at an area smaller than your back garden.

Drilling into the seafloor to recover rocks and sediments, and to set up seafloor observatories, allows scientists to explore and better understand these uncharted subterranean environments. Buried in seafloor sediments and the underlying crust is a rich history of the waxing and waning of glaciers, the creation and ageing of oceanic lithosphere (the hard rock crust), the evolution and extinction of microorganisms, and the building and erosion of continents.

The study of the deep oceans has revealed much about the Earth's dynamic nature, but we are only just beginning to recognise that plate tectonic processes and the accompanying changes in ocean circulation and climate have influenced the evolution of life and the cycling of many elements and minerals. The deep oceans are an integral yet poorly understood part of the Earth system.

Here we spell out what we see as the key issues in the study of the deep oceans, what we know with a reasonable level of certainty, and what we need to find out.

Ocean drilling leaflet (1.2MB)