The Tournaisian and Visean platform carbonate successions of the UK and Ireland
initially relied upon development of coral and brachiopod zonations to aid correlation.
However, such zones are strongly facies-controlled and are only of local to regional
significance. Over recent years, emphasis has been placed upon the use of foraminifers,
and notably conodonts, to define international stages. They have been studied
increasingly within the Tournaisian and Visean successions of the UK and Ireland, but
are of limited stratigraphical value in younger Carboniferous strata. Ammonoids
(goniatites) provide the greatest biostratigraphical resolution for the late Visean,
Namurian and early Westphalian Stages. Some ammonoid biozones can be recognised
across Western Europe and some biozones are applicable globally. However, the
marine bands that contain these ammonoids may be absent towards basin margins and
marine influence is lost entirely throughout late Westphalian and Stephanian times.
Within strata lacking ammonoids, biostratigraphical correlation initially relied upon
recognition of non-marine bivalve zonation, but over recent decades palynomorphs
(miospores) and plant macrofloras have assumed greater importance
