Parting lineation (also known as current lineation or primary current lineation) is a subtle sedimentary structure in which sand grains are aligned in parallel lines or grooves on the surface of a body of sand (or lithified as a sandstone).[1] The orientation of the lineation is used as a paleocurrent indicator, although the precise flow direction (i.e. upstream vs. downstream) is often indeterminable. They are also the primary indicator of the lower part of the upper flow regime bedform.
- ^ Boggs, S., Principles of Sedimentology and Stratigraphy, 3rd Ed., pgs. 125-126