Serpukhovian

The Serpukhovian is a very important time period in Earth's history. It is the uppermost or youngest stage 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 up with 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 help understand how Earth changed and developed millions of years ago.

Name and definition

The Serpukhovian Stage was proposed in 1890 by Russian scientist Sergei Nikitin and was named after the city of Serpukhov, close to Moscow. It became part of the official geologic time scale in 1974.

Scientists define the beginning of the Serpukhovian by looking for a special type of tiny fossil called a conodont. The end of this stage is marked by another conodont fossil. Two possible locations have been suggested to mark this stage officially, one in the Urals in Russia and another in Guizhou, China.

Subdivision

The Serpukhovian is divided into different parts based on fossils found in rock layers. In Europe, it includes 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 largest extinction event of the Carboniferous Period happened in the early Serpukhovian. This event caused many different kinds of sea creatures, like crinoids and rugose corals, to disappear. After this, new sea creatures appeared, but there were fewer types of them.

Scientists have different ideas about how many sea creatures disappeared during this time. Some think it was around 23-24%, while others believe it was as high as 39%. This extinction mainly affected creatures that needed warm water, as the ocean cooled and their homes changed.