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October 11, 2017

Eureka often accompanies this EarthWord.

EarthWords is an on-going series in which we shed some light on the complicated, often difficult-to-pronounce language of science. Think of us as your terminology tour-guides, and meet us back here every week for a new word!

Image shows two scientists in hard hats collecting a research core aboard a drill rig
Scientists aboard the D/S Chikyu prepare to collect a research core drilled from marine sediments in the Indian Ocean. This research is part of the 2015 Indian National Gas Hydrate Program Expedition 02 (NGHP-02), which is a follow-up to the 2006 NGHP-01. NGHP-02 identified several large deposits of potentially producible gas hydrates in the Indian Ocean. This project was led by the Government of India, with scientists from Japan and the United States, including the U.S. Geological Survey. Read more here. (Credit: Tim Collett, USGS. Public domain.)

The EarthWord: Discovery


  • This one sounds pretty self-explanatory, but it actually has a very specific meaning, at least in the field of energy and mineral resources.

  • A “discovery” typically is an official announcement by a private company that shows an energy or mineral resource is present. For instance, in the oil and gas world, a discovery well is the first well that reveals the presence of a petroleum-bearing reservoir.  Information on new oil field discoveries is compiled and reported by the EIA.


  • Discovery comes from the Latin prefix dis, meaning "opposite of” and the Latin word cooperire, meaning "to cover up.”

Use/Significance in the Earth Science Community:

  • Discoveries are the primary way that companies identify that an energy or mineral resource actually exists. A discovery is not always economic (commercially favorable) to produce, and a discovery may require additional testing and study, but it is a necessary precursor to production (before it contributes to our energy and mineral supplies).


  • USGS energy and mineral resources assessments are not discoveries. USGS does not explore for new energy or mineral resources, but does collect rock, core, and other samples to help better understand how these resources form and the geological occurrence of these resources on a regional scale.

  • Examples include studies of the Eagle Ford shale and our collaborative research on gas hydrates.

  • Instead, USGS assesses undiscovered resources, providing estimates of energy and mineral resources that we estimate to exist based on our understanding of the geology and our statistical models, and current industry practices, such as the types of technology used to develop and produce discovered resources. These estimates would have to be proven through discovery.  When USGS releases a new resource assessment, this takes into account available information from previous discoveries and and production made by industry.

    Image shows a McKelvey box, a diagram that shows the difference between resources and reserves.
    A McKelvey box, a diagram that shows the difference between resources and reserves. As one travels from resources to reserves, both geologic certainty and economic feasibility increase.(Public domain.)
  • Read more about our energy resource assessments here and about our mineral resource assessments here.

Next EarthWord: Our Energy Week is heating up with this next EarthWord...

Hungry for some science, but you don’t have time for a full-course research plate? Then check out USGS Science Snippets, our snack-sized science series that focuses on the fun, weird, and fascinating stories of USGS science.

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