Article: Belemnites in biostratigraphy
Belemnites are common fossils in Mesozoic sequences. They have been used as biostratigraphical tools since the nineteenth century, but the only belemnite biozonation in general use is that of the Upper Cretaceous of northern Europe. The potential for broader application of belemnites in biostratigraphy is discussed with reference to first principles. In essence, belemnites are widespread, were relatively fast evolving and largely facies independent, in addition to being relatively simple to identify, abundant and robust. Current belemnite biozonal schemes are discussed in relation to belemnite palaeobiogeographical distribution. It is clear that the greatest potential for intercontinental correlation exists at times of global expansion (e.g. the Toarcian). The scope for development of local or regional belemnite biozonations of stratigraphical value is considerable in uppermost Lower Jurassic through to Upper Cretaceous successions. These are worthy of development, if only for comparison with those based on the undoubtedly excellent, but sometimes uncommon, ammonites.