Stratigraphy of ENA rift basins. Strata within the Mesozoic rift basins are packaged into four tectonostratigraphic (TS) packages that may be separated by unconformities (periods of non-deposition or erosion). Note that TS4, which contains Early Jurassic lava flows, is not present in any of the southern basins. Most of the tectonostratigraphic sequences begin with a fluvial unit, then a shallow-water to deep-water lacustrine unit, followed by an upward-shoaling lacustrine to fluvial unit. This is known as tripartite stratigraphy. Modified from Olsen (1997) and Schlische (2002).