CHANGES IN THE TRACE FOSSIL BIOTA ACROSS THE PROTEROZOIC PHANEROZOIC BOUNDARY

Trace fossils became relatively diverse in shallow-water clastic seas in the late Proterozoic (Vendian), with a further significant increase in abundance, diversity and complexity in the Tommotian and Atdabanian. Little change followed in the remainder of the Lower Palaeozoic. Traces typical of deeper-water facies evolved in shallow water during the Vendian and early Cambrian, and may have slowly migrated into the deep ocean during the remainder of the Lower Palaeozoic. There are a limited number of short-ranging ichnogenera which may be useful for correlation but the first appearance of ichnogenera may be a more satisfactory method. Three trace fossil zones covering the ranges Redkino and Kotlin, Rovno and Tommotian-lower Atdabanian are recognized and may be useful for world-wide correlation.