The Avalon assemblage was the first of three Late Ediacaran biotic assemblages, lasting from about 575 million to 560 million years ago. It was followed by the White Sea assemblage, but some time periods overlap between these groups. Earlier large fossils, mostly from algae, are found in the Lantian Formation. However, Avalon-type locations provide some of the earliest evidence of possible ancestors of animals, which are part of the Ediacaran biota.

Research history

In 2003, Ben Waggoner first suggested that the Ediacaran biota was divided into three separate groups.

Geography

Most Avalonian fossil sites are found in the central United Kingdom and eastern Newfoundland, which were once connected as part of the Avalonia microcontinent. Outside of Avalonia itself, other sites are part of the Avalon assemblage, such as the Olenek Uplift in Siberia and Sekwi Brooke in the Northwest Territories of Canada.

Biota

Deep-water rangeomorphs and some arboreomorphs were the main types of life in the Avalonian biota, although other large fossil groups have also been found. Some groups, like dipleurozoans, which are common in the Ediacaran biota, are not found in Avalon sites but appear later in the White Sea assemblage. However, the Avalon biota includes all the different body shapes that later appeared in other assemblages.