UGA Stratigraphy Lab

The data is in the strata

Progradational Stacking

Shown below is a set of progradationally stacked parasequences developed along a wave-dominated siliciclastic coastline. Here, offshore facies are muddy and characterized by the development of covered slopes, such as near the bottom of the photography. Transition zone facies consist of interbedded mudstone and sandstone, whereas shoreface and foreshore facies consist only of sandstone. In this example, foreshore facies are commonly overlain by a coal, which bleaches the underlying foreshore to white, in contrast to the buff colors of the shoreface. In this photo, note the overall coarsening upward from offshore facies near the bottom to shoreface and foreshore facies near the top. Although individual flooding surfaces can be recognized by reverals in this trend, they are not as well developed as in a retrogradational set of parasequences. This photograph is from a classic exposure of the Cretaceous Blackhawk Formation in Gentile Wash near Helper, Utah.

Return to parasequence sets