Primary Current Lineation or Parting Lineation
The terms “primary current lineation” and “parting lineation” have both been applied to the same depositional feature of sedimentary rocks. It is agreed that the origin is a streamlining effect on loose sand grains parallel with current direction. A superficially similar effect is seen on parting planes of certain metamorphic rocks and is due to the intersection of s-surfaces. This lineation is at right angles to the tectonic movement. It is suggested that the term “primary current lineation” be retained for the sedimentary depositional feature to avoid confusion with the lineation imposed by movement within metamorphic rocks.