How Can We Define Stratal Units? We want to subdivide a seismic section into meaningful stratigraphic units How can we do this? Consider for a moment how you would do this with a photo of an outcrop Wouldn’t you look for evidence of a significant breaks in deposition? SLIDE 14 Our next key question is: How can we define stratal units, especially on seismic lines? Consider for a moment how you would do this with a photo of an outcrop, such as this one of the North wall of the Grand Canyon Wouldn’t you look for evidence of significant breaks in deposition? Can you see evidence for a major break in deposition on this photo? Courtesy of ExxonMobil L 11 – Stratigraphic Analysis