15 - Palaeoclimatic implications of the energy hypothesis from Neogene corals of the Mediterranean region

Summary

Introduction

Fossil corals have long been used for palaeoenvironmental interpretation, largely because many extant taxa are restricted to warm shallow tropical marine waters, and this is commonly extrapolated to the fossil coral record on simple uniformitarian grounds. For the most part, this approach has been largely qualitative, the presence of corals, or more particularly, the presence of ‘reef corals’, at a particular place being used to infer a warm climate, and their absence to infer a cool climate. By extension from this, the northernmost and southernmost limits of reef coral distributions in the past have also been used to infer times of global warming and cooling (e.g. Adams et al., 1990), since the global reef coral belt has varied in width through time. The present paper is a preliminary attempt to make more use of the potential of corals, by invoking the ‘energy hypothesis’, which provides a quantitative relationship between taxonomic richness and prevailing temperatures. This is used here to derive actual palaeotemperatures from the Miocene coral record of the Mediterranean region.

Palaeontological and taxonomic background

The corals which are the subject of this contribution belong to the order Scleractinia which first appeared in the Middle Triassic (Roniewicz & Morycowa, 1993). Scleractinia are also common in modern seas, where they are a major biotic element of coral reef habitats like the Great Barrier Reef, as well as forming deep and cool water coral banks (Stanley & Cairns, 1988).