Ocean drilling

Ocean drilling recovers cylindrical samples of seafloor sediment and rock using boreholes drilled from research vessels. These cores preserve evidence of ocean history, climate change, and Earth’s crust.

Scientific drilling vessel: A ship equipped to drill boreholes and recover geological samples from beneath the seafloor. Its dynamic positioning and drilling equipment keep a borehole stable over deep water.
Project Mohole: A 1950s and 1960s American effort to drill through oceanic crust toward the Mohorovičić discontinuity. It established the ambition and technical groundwork for scientific drilling from ships.
Paleoclimatology: The study of past climates using evidence preserved in geological, biological, and chemical records. Marine cores preserve long sequences of climate-sensitive material.
Seafloor dredging: A method that drags a toothed collection device across the seabed to retrieve loose rock and sediment. Unlike drilling, dredging samples exposed material without preserving a depth-ordered core.
Seafloor spreading: The process by which new oceanic crust forms at mid-ocean ridges and moves outward. Drilling recovered progressively older crust away from ridges, supporting this process.
Drill string: A connected length of drill pipe that transmits force and carries drilling fluid between a vessel and a drill bit. It links the ship’s machinery to the bit at the seafloor.
Deep Sea Drilling Project: A United States ocean-drilling program that operated the vessel Glomar Challenger from 1968 to 1983. Its cores provided decisive evidence for seafloor spreading and plate tectonics.
Foraminifera: Single-celled organisms, many of which build calcium carbonate shells preserved in marine sediments. Their fossils reveal past ocean temperatures and chemistry in drilled cores.
Gravity corer: A coring device that penetrates seabed sediment under its own weight, usually recovering shallow samples. It collects surface sediment more simply but cannot reach drilling depths.
Plate tectonics: The theory that Earth’s lithosphere is divided into moving plates whose interactions shape the planet’s surface. Ocean-floor age patterns from drilling became key evidence for the theory.

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