Carnian

The Carnian is the earliest time period of the Late Triassic Epoch. It 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 change a lot.

Another change happened right at the end of the Carnian, when the Norian period began. This time 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 land and oceans much like the rest of the Triassic. Most land was one huge continent called Pangaea. There was one big ocean named Panthalassa. This ocean had a western part called Paleo-Tethys. Rocks from this part can be seen today in southeastern Europe, the Middle East, the Himalayas, and on the island of Timor.

There were no ice caps at this time. The climate was usually dry near the equator. But there was a time when the tropics became very wet. This rainy time is called the "Carnian Pluvial Event". It happened between the latest early Carnian and the start of the late Carnian.

Carnian life

Main page: Category:Carnian life

The Carnian period happened around 237 to 227.3 million years ago. During this time, many changes occurred in life both undersea and on land.

In the oceans, tiny creatures called calcareous nanoplankton appeared for the first time. These included early forms of coccolithophores, which help us learn about ancient seas.

Many new animal groups appeared during the Carnian, both in the water and on land. In the seas, special shellfish like the ammonoid Trachyceras and the bivalve Halobia lived. Coral reefs built 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 these early dinosaurs were small, they would later become the main land animals for millions of years.

Classic localities and Lagerstätten

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

The Ischigualasto Formation in northwestern Argentina has important ancient vertebrates, including some of the earliest known dinosaurs. The Madygen Formation in Kyrgyzstan has many 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)