Stratigraphical Classification

In Western Europe, the Carboniferous is divided (Table VII) into two sub-systems. At the base is the Dinantian, which contains the limestones of the major Carboniferous transgression, and at the top the Silesian, which contains much mudstone and sandstone (and includes the Coal Measures) and represents the retreat of the Carboniferous seas.

The Dinantian (also used as a Series name) is divided into stages which broadly coincide with the larger marine transgressions and regressions shown by the rocks; each stage is recognizable from the new faunal elements brought in by each transgression.

Although the actual species in each type of community vary throughout the Dinantian, the ecogroups as units survive throughout and even extend into the Upper Carboniferous.

The Silesian is divided into stages which are based for the most part on individual marine transgressive horizons, identified by widely distributed goniatites, but occurring through a very limited stratal thickness. The goniatites were evolving so fast in the Upper Carboniferous that each marine horizon generally contains its own distinctive goniatite species; thus there are many different assemblages but rather few communities.

In Russia and North America the Carboniferous rocks arc classified in a different way, partly because of facies differences, but the broad correlation between Western Europe, Russia and North America is not a great problem.

Western Europe

Was this article helpful?

0 0

Post a comment