Serpukhovian

The Serpukhovian is an important time in Earth's history. It is the last or most recent part of the Mississippian, which is the lower part of the Carboniferous. This time period lasted from about 330.3 million years ago to 323.4 million years ago.

The Serpukhovian comes after the Visean stage and is followed by the Bashkirian stage. It matches the lower part of the Namurian Stage in Europe and the middle and upper parts of the Chesterian Stage in North America. Scientists use the Serpukhovian to learn about how Earth changed and grew millions of years ago.

Name and definition

The Serpukhovian Stage was suggested in 1890 by Russian scientist Sergei Nikitin. It was named after the city of Serpukhov, which is near Moscow. It became an official part of the geologic time scale in 1974.

Scientists start the Serpukhovian by looking for a special tiny fossil called a conodont. They end this stage with another conodont fossil. Two places have been offered to mark this stage officially. One is in the Urals in Russia, and the other is in Guizhou, China.

Subdivision

The Serpukhovian is divided into different parts based on fossils found in rock layers. In Europe, it has three zones based on tiny tooth-like fossils called conodonts and three zones based on single-celled organisms called foraminifera. North America also has four conodont zones.

In Russia and Eastern Europe, the Serpukhovian is split into four parts, named after places near Serpukhov. The United Kingdom matches the Serpukhovian with part of its own regional stage called the Namurian. In North America, it lines up with the upper part of the Chesterian stage, and in China, it is similar to the Dewuan stage.

Serpukhovian extinction

The biggest extinction event of the Carboniferous Period happened in the early Serpukhovian. Many kinds of sea creatures, like crinoids and rugose corals, disappeared. After this, new sea creatures appeared, but there were fewer types of them.

Scientists are not sure exactly how many sea creatures disappeared during this time. The extinction mainly affected creatures that needed warm water, as the ocean cooled and changed.