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Paleocurrent

Geological indicator of water flow

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated July 24, 2023
Image credit is listed at the end of this article.

A paleocurrent or paleocurrent indicator is a geological feature (typically a sedimentary structure) that helps one determine the direction of flowing water in the geologic past. This is an invaluable tool in the reconstruction of ancient depositional environments.

There are two main types of paleocurrent indicators:

  • Unidirectional, which give a clear, single direction of flow
  • Bidirectional, which give a good linear direction, but it is unclear which direction along the linear trend the water flowed.

Paleocurrents are usually measured with an azimuth, or as a rake on a bedding plane, and displayed with a Rose Diagram to show the dominant direction(s) of flow. This is needed because in some depositional environments, like meandering rivers, the paleocurrent resulting from natural sinuosity has a natural variation of 180 degrees or more.

Below are a partial list of common paleocurrent indicators:

01Unidirectional

  • Cross-bedding, the axis of a trough cross bed or the down-dip direction of a tabular cross bed point the direction of paleo flow.
  • Current ripple marks, will have the short side of the ripple pointing down stream.
  • Sole markings/flute casts, the short, steep side will point up stream, and the long, tapered side points down stream.
  • Imbrication, clasts line up in the direction of flow.
Flute cast, showing paleocurrent to the upper right of pic
Flute cast, showing paleocurrent to the upper right of pic

02Bidirectional

Parting lineation, from lower right to upper left; Kayenta Formation, Canyonlands National Park.
Parting lineation, from lower right to upper left; Kayenta Formation, Canyonlands National Park.
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Sources and credits

This article is adapted from the Wikipedia article “Paleocurrent”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

Images, from Wikimedia Commons:

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