A stratigraphic summary chart on which geologic time is plotted as the vertical scale, and distance across the area of interest as the horizontal scale, and on which a variety of stratigraphic information is brought together (Mitchum, 1977). These are also called Wheeler diagrams after the geologist who initially formalized this time-stratigraphy concept in 1958 and expanded on this in 1964. His diagrams display both the horizontal distribution of the contemporaneous component sedimentary layers of a sequence but also the significant hiatuses in sedimentation. 
On the cross section the A5 surface
is truncated by an unconformity but on the area-time plot the A5 surface
extends across the entire region, with a large portion of it is within the
lacuna domain
On the cross section above the A5 surface
is truncated by an unconformity but on this area-time plot of Wheeler (1964) the A5 surface
extends across the entire region, with a large portion of it is within the lacuna domain
These diagrams enable the analysis of a stratigraphic cross section so the contemporaneous component sedimentary layers and
systems tracts of
sequences can be considered in terms of their relationship to baselevel,
hiatuses, timing and geographic location.
Diagrams are commonly are built from seismic and/or geologic cross-sections and may used to identify trends in potential hydrocarbon reservoir, seal and/or source rocks facies.
Mitchum Jr., R.M., 1977, Seismic
stratigraphy and global changes of sea level. Part 11: glossary of terms used in seismic
stratigraphy. In: Payton, C.E. (Ed.), Seismic
Stratigraphy––Applications to Hydrocarbon Exploration, vol. 26. A.A.P.G. Memoir, pp. 205–212.
Wheeler, H.E. 1958, Time
Stratigraphy. AAPG Bulletin, Vol. 42, p 1047-1063.
Wheeler, H.E. 1964, Baselevel,
Lithosphere Surface, and Time-
Stratigraphy Geological Society of America
Bulletin, July 1964, v. 75, no. 7, p. 599-610