primary stratigraphic trap

primary stratigraphic trap

[′prī‚mer·ē ¦strad·ə¦graf·ik ′trap]
(geology)
A stratigraphic trap formed by the deposition of clastic materials (such as shoestring sands, lenses, sand patches, bars, or cocinas) or through chemical deposition (such as organic reefs or biostromes).