Cycles with Episodicities of Tens to Hundreds of Millions of Years

Abstract

It is becoming increasingly clear that global climate, oceanic circulation, sedimentation patterns, biotic diversity, and evolutionary trends are all linked to variations in sea level (Fischer 1984; Worsley and Nance 1989; Worsley et al. 1984, 1986, 1991; Veevers 1990). These linkages can be traced through the long-term cycle of supercontinent assembly and dispersal (Fig. 6.1), and many of the same changes can also be observed on shorter time scales. For example, certain trends in sedimentation patterns are related to the position and direction of change in sea level relative to continental margins, and there is some evidence (touched on below) for such variations occurring with episodicities of millions to tens of millions of years.