Carnian

The Carnian is the earliest time period of the Late Triassic Epoch, which happened a very long time ago, between 237 and 227.3 million years ago. It came after the Ladinian period and was followed by the Norian period. Even though there weren’t any big extinctions that marked the start or end of the Carnian, important changes happened during this time.

One big change during the Carnian was a climate event called the Carnian pluvial episode. This was a time when there was a lot of heavy rain over many years. Scientists think this wet climate may have caused some animals and plants to die out or to change a lot.

Another change happened right at the end of the Carnian, when the Norian period began. This time also saw some extinctions, meaning some species that lived during the Carnian did not survive into the next period. The Carnian helps scientists understand how Earth’s climate and life changed long ago.

Stratigraphic definitions

The Carnian was named in 1869 by Edmund von Mojsisovics. It might be named after the Carnic Alps, the Austrian region of Carinthia, or the Carnia historical region in northeastern Italy. The base of the Carnian Stage is defined by the first appearance of the ammonite species Daxatina canadensis.

The Carnian can be divided in different ways. Some areas split it into two parts, while others use three parts. In the Tethys domain, the Carnian includes several zones defined by different ammonite species.

Paleogeography and climate

The Carnian period had a similar geography to the rest of the Triassic. Most land was joined into one huge continent called Pangaea, and there was one big ocean named Panthalassa. This ocean had a western part called Paleo-Tethys, whose rocks can now be seen in southeastern Europe, the Middle East, the Himalayas, and even on the island of Timor.

There were no ice caps during this time, and the climate was usually dry near the equator. However, there was a time when the tropics became very wet, known as the "Carnian Pluvial Event". This rainy period happened between the latest early Carnian and the start of the late Carnian.

Carnian life

Main page: Category:Carnian life

The Carnian period, which happened around 237 to 227.3 million years ago, saw many important changes in life undersea and on land. In the oceans, tiny creatures called calcareous nanoplankton began to appear for the first time. These included early forms of coccolithophores, which are important for understanding ancient seas.

On land and in the water, many new animal groups appeared during the Carnian. In the seas, special types of shellfish like the ammonoid Trachyceras and the bivalve Halobia lived. Coral reefs made by modern kinds of corals also became more common. On land, the first clear evidence of dinosaurs appeared, such as Herrerasaurus and Eoraptor. Other important animals included archosaurs like phytosaurs and rhynchosaurs. Though dinosaurs were small at first, they would later become the dominant land animals for millions of years.

Classic localities and Lagerstätten

The lower Carnian fauna from the San Cassiano Formation in the Dolomites of northern Italy has been studied since the 1800s. Many fossil sites are found near Cortina d'Ampezzo and the village of San Cassiano. These fossils include many types of sea creatures like ammonoids, snails, clams, and corals.

The Ischigualasto Formation in northwestern Argentina contains important ancient vertebrates, including some of the earliest known dinosaurs. The Madygen Formation in Kyrgyzstan has produced thousands of fossils of insects, plants, and animals.

Notable Formations

• Chañares Formation (Argentina)
• Denmark Hill Insect Bed (Queensland, Australia)
• Ischigualasto Formation (Argentina)
• Los Rastros Formation (Argentina)
• Molteno Formation (South Africa)
• Potrerillos Formation (Argentina)
• Santa Maria Formation (Rio Grande do Sul, Brazil)
• Stuttgart Formation (Germany)
• Xiaowa Formation / Wayao Member of the Falang Formation (Guizhou and Yunnan, China)
• Zhuganpo Formation / Zhuganpo Member of the Falang Formation (late Ladinian - early Carnian) (Guizhou and Yunnan, China)