The White Sea assemblage, also called the Ediacaran assemblage, is the second group of fossils from the Late Ediacaran period. It comes after the Avalon assemblage and before the Nama assemblage.

Overview

This group is named after Russia's White Sea or Australia's Ediacara Hills. It has more variety of life forms than the Avalon or Nama groups. It lasted from about 560 million to 550 million years ago. It showed an increase in the number of different genera compared to the Avalon group. It ended with a major change in animal life, often called the first major event of the end-Ediacaran extinction. Only 20% of the species found in the White Sea group were present in the later Nama group, even though the ways fossils were preserved were similar. Most fossils are found as impressions in layers of microbes, but some are found in sand layers.

Australia

In Australia, these fossils are found in red soil types. These soils formed from loess and flood deposits in a dry, cool climate long ago. Many fossil beds from this time exist in the Ediacara Hills of South Australia, located west of the Flinders Ranges.

In the mid-1980s, scientists discovered rich fossil beds on a cattle station named Nilpena Station. This site became important for research and was later protected by being nominated for World Heritage status. The entire property is now owned by the state government and is part of the Nilpena Ediacara National Park.

Since the early 2000s, about 40 fossil surfaces have been uncovered in the Ediacara Member of the Rawnsley Quartzite in the Ediacara Hills. These surfaces preserve organisms from the White Sea Assemblage. The fossil bed called 1T-F has the greatest variety of Ediacaran fossils found so far. This bed contains more than 400 fossils from 16 different genera.