Abstract

A standard scheme of stages for the Tertiary is presented, and their ages discussed. Sequence stratigraphy was becoming established as an approach to the analysis of the Spanish Tertiary before it became widely used internationally. Geomagnetic polarity reversal stratigraphy has been shown to be an important approach to the dating of some non-marine successions.

Introduction

Basin stratigraphy generally provides the best key to the geometry and timing of development of the basin. Because much of this book reports recent work on the stratigraphic analysis of the various local Tertiary successions, this chapter has been written to introduce Tertiary stratigraphic terminology for those unfamiliar with it, and to draw attention to some of the special techniques used on the Spanish material.

The Tertiary stages

A geologic time scale 1989 or GTS89 (Harland et al, 1990) is the starting point of this introduction. It has been widely used because of its broad and balanced coverage.

Fig. 1 presents the scheme of eras, sub-eras, periods and stages proposed for standard use in GTS 89. The stages are, to a great extent, the basic units for indicating the ages of rocks in the Tertiary successions, and are now based on global correlations using planktonic oceanic faunas and floras. Fig. 1 also shows correlations between the various standard stages and certain stages and divisions used more locally in Spain. These local schemes have been developed where correlations with the standard stages are particularly uncertain.