Stratigraphical classification and all that

Abstract

Quantitative treatment of the geological sciences must remain limited; there continues to be need for a language of words. This is keenly felt in stratigraphy, where the practising geologist is dismayed by the effusions of the stratigraphical philosophers. The situation, in so far as it appears to remain in some ways obscure or troublesome, is briefly reviewed in terms of lithostratigraphy. biostratigraphy. and chronostratigraphy. A revised version of a controversial diagram is presented, in which the role of the boundary stratotype as anchor point is believed to be clarified. Finally a synthesis is attempted of relationships between the various stratigraphical procedures and the provision of dates in years through the parallel discipline of geochronometry.

Devonian–Carboniferous brachiopod zonation in the Tarim Basin, northwest China: implications for biostratigraphy and biogeography

“…In terms of the latest International Stratigraphic Guide (Salvador 1994) and that of Holland (1978), these brachiopod zones may be mostly termed acme biozones. An acme zone relies for definition on the recognition of a maximum occurrence of a species that might otherwise range both higher and lower in the succession.…”

“…Brachiopod zones in the Upper Devonian and Carboniferous rocks of the Tarim Basin are based on a nominate species and an accompanying assemblage of species, following Opel's original concept (Berry 1968). In terms of the latest International Stratigraphic Guide (Salvador 1994) and that of Holland (1978), these brachiopod zones may be mostly termed acme biozones. An acme zone relies for definition on the recognition of a maximum occurrence of a species that might otherwise range both higher and lower in the succession.…”

Utility and precision of Silurian graptolite biozones

“…My recommendations are that we use that term wherever possible and that we aspire to use the assemblage-biozone principle (with as many species as possible) to define them, whilst allowing special cases, such as acme biozones, if they prove useful. Thus biozone I use in a slightly different sense to Harland et al (1972) and Holland (1978), in that the word biozone, used by itself (as it so often is), implies assemblage biozone; and only if it is used in a different, more restricted sense should that restriction be spelt out, e.g., acme biozone.…”

The end of the Pleistocene: a general critique of chronostratigraphic classification

“…the SilurianlDevonian boundary' (p. 69). Holland (1978) cautions that the golden spike recently driven onomatopoetically at Klonk, Czechoslovakia, to represent the SilurianlDevonian boundary may prove to be misplaced when fossils are found in intervening beds.…”