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Keep up to speed with Falkor research cruise with our latest seafloor syntax!

Photograph of Methane-derived authigenic carbonate (MDAC) rocks on the seafloor on the U.S. Atlantic margin

Methane-derived authigenic carbonate (MDAC) rocks on the seafloor on the U.S. Atlantic margin

(Public domain.)

From June 12 to July 3, the U.S. Geological Survey and Schmidt Ocean Institute will be conducting a research cruise off the coast of Oregon and Washington, hunting deep-sea bubbles and the creatures that eat them. While we post stories about our findings, we’ll also be posting little vignettes like these, in which we serve as your terminology tour-guides to the unusual and hard-to-pronounce words that dwell in the depths of deep-ocean science.

The WaterWord: Authigenic


  • Although some people are born with a wanderlust, wanting to travel all over, some seem to be ready made homebodies. And rocks that are authigenic are the homebodies of geology.

  • Authigenic means that rock formed where it is currently located. That’s in contrast to rocks that form from materials that were transported from elsewhere, like sedimentary rocks made up of river sediments carried far from their point of origin.


  • Authigenic comes from the Greek authi-, meaning “there,” and genesis, meaning “to be born,” or “to be created.”

Photograph of Methane-derived authigenic carbonate

Methane-derived authigenic carbonate (MDAC) features from a sample obtained at Baltimore Canyon

(Credit: Nancy Prouty, USGS Pacific Coastal and Marine Science Center. Public domain.)

Use/Significance in the Earth Science Community:

  • Authigenic sediments are the primary parts of deep-sea sedimentary rocks. Carbonates are some of the more common types of authigenic sedimentary rocks on the seafloor.

  • Many of them form when methane or other hydrocarbon seeps fill the nearby ocean water with minerals that eventually precipitate out, building up in deposits that eventually form sedimentary rocks.

U.S. Geological Survey/Schmidt Ocean Institute Use:

  • USGS and SOI are collaborating on a research cruise off the coast of Oregon and Washington that will study methane seeps and what effects they have on the local environment, including the geology surrounding them. This will likely include certain authigenic rocks.

Next WaterWord: Foraminifera

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