Drumian

The Drumian is an important time in Earth's history. It is part of the Miaolingian Series of the Cambrian period, known for its many fossils and changes in life on our planet. The Drumian comes after the Wuliuan stage and before the Guzhangian stage.

Scientists mark the start of the Drumian by looking for a special kind of ancient sea creature called a trilobite. They look for the first appearance of a trilobite named Ptychagnostus atavus, which lived about 504.5 million years ago. The end of the Drumian is marked by the first appearance of another trilobite, Lejopyge laevigata, around 500.5 million years ago.

Studying the Drumian helps us learn about how life changed during this time. Fossils from this period show many new and different kinds of ancient sea life, giving clues about how ecosystems developed long before humans existed.

GSSP

The GSSP is found in the Drumian section in the Drum Mountains, Millard County, Utah, United States. This place is named after the Drum Mountains. It has layers of rock called the Wheeler Formation. The start of the Drumian stage is shown by a special layer of limestone in these rocks.

Major events

The Drumian stage had an important change called the Cambrian Drumian carbon isotope excursion (DICE). This change happened when deep waters with low oxygen moved closer to the surface. This made it hard for reef ecosystems to recover after earlier extinctions during the Cambrian period. Later in the Drumian stage, many sea creatures began to appear more often before another extinction event.

Paleontology

The Drumian stage is known for many fossils of ancient sea creatures. Scientists found remains of sponges, palaeoscolecids, and euarthropods. These include large, unusual animals called radiodonts. The fossils help us learn about ocean life from millions of years ago.