EarthWord–Alluvial Fan

Release Date:

On the 1st day of summer, we’ve got an #EarthWord that’s a fan-just not the cooling kind...

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 an alluvial fan in Iran.
Image shows an alluvial fan in Iran. By NASA image created by Jesse Allen, using data from NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team. Caption by Rebecca Lindsey, based on interpretation provided on the ASTER Project Science Imagery Gallery Website. - http://earthobservatory.nasa.gov/IOTD/view.php?id=36041, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9496676

The EarthWord: Alluvial Fan

Definition:

  • Remember earlier when we covered fluvial? This word’s closely related to it. An alluvial fan happens when a fast-moving mountain stream empties out onto a relatively flat plain. All of the sediment it was carrying falls out as the water slows down.

Etymology:

  • Alluvial comes from the Latin alluvius, which meant “washed against.”

Use/Significance in the Earth Science Community:

  • Alluvial fans are part of the natural process of how mountains are eroded into plains. They also play an important role in spreading nutrients around.

USGS Use:

Next EarthWord: See a flock of birds fall from the sky? There’s an EarthWord for that, and it isn’t “apocalypse”…

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