West-Pacific Stratigraphic Correlation

Abstract

THE development of reliable methods of world-wide stratigraphic correlation involves the gradual replacement of empirical and traditional ‘index fossils’ by zonal index species selected on the basis of carefully analysed factors concerning their evolution and distribution. This approach favours abundant fossils to which statistical methods of population study can be applied, such as Foraminifera; rapidly evolving lineages, such as larger Foraminifera; and widespread forms, relatively independent of facies, such as planktonic organisms. It also necessitates a major effort to clarify stratigraphic terminology and classification which is expected to be significantly advanced soon as a result of the work of the Commission on Stratigraphy of the International Geological Congress. The framework of the conventional stratigraphic subdivisions of geological time, dating back to the time when geological knowledge began to accumulate long ago in Europe, is found to lack precision and to suffer from other deficiencies when attempts are made to accommodate in it the results of precise stratigraphic correlation in previously unknown parts of the world. Patient co-operative work of stratigraphers and palaeontologists in different continents is required in order to overcome the difficulties and misunderstandings resulting from an over-extension of weakly founded terms and concepts. As Gignoux¹ has stated, it is essential first to establish local stratigraphic sequences (on a rock stratigraphic and zonal biostratigraphic basis, I might now add) and to generalize them only cautiously.