Paleocén

Article

May 28, 2022

The Paleocene (66.0-55.8 Ma before the present) is the oldest period (professionally separated) of the Cenozoic era and the beginning of the "age of mammals". It dates to 66 to 56 million years ago and, together with the Eocene, Oligocene and Miocene, is part of the Paleogene period, which together with the younger Neogene forms the informal Tertiary time unit, ie the Tertiary in Czech. It is characterized by a tropical climate with temperatures averaging 24-25 ° C, ie 10 degrees Celsius more than today. The name Paleocene was defined by the French paleobotanist and geologist Wilhelm Philippe Schimper in 1874, when he described sediments around Paris. Etymologically, it is a compound of the Latin "paleo", ie old, and the Greek adjective "καινός" (kainos) - Latinized to "caenus", meaning "new". So in this context it can be translated as "old new age". The Paleocene division is divided into three further stages: dan, seeland and thanet.

Geology and climate

At the very beginning of the Paleocene as the initial epoch of the Cenozoic is a global catastrophe, which seems to have been caused by the impact of the asteroid Chicxulub in the area of ​​today's Gulf of Mexico. He probably caused a series of subsequent events that completed the work of destruction. It is here that the main flowing phase of the volcanic structure known as the Deccan Traps in India falls. Massive layers of basalt were formed here 67 million years ago, but it is no coincidence that the strongest phase of the outflows took place at a time when the impact of the asteroid shook the entire planet. Other consequences of the impact were giant tsunamis in all oceans, shading of sunlight by dust, seismic waves, fires and more. In the Paleocene, the distance of the Americas from Europe and Africa continues, thus expanding the Atlantic Ocean. The Alpine fold caused by the approach of the Eurasian and African tectonic plates continues from the Mesozoic. This leads to the gradual narrowing of the Tethys Ocean. Antarctica remains associated with Australia, and India is separated from the rest of the mainland as a large island and travels relatively quickly, with the end of the Paleocene dating back to the beginning of its collision with Asia, which later led to the uplift of the Himalayas in the Miocene. moist and tropical as in the late Mozozoic and gradually warmed further. The northern oceans did not freeze, and lush vegetation, including forests, could grow on the mainland beyond the Arctic Circle. Precipitation activity was more or less uniform over the entire surface of the Earth during the year. The Paleocene ends with a period of about 200,000 years, which is called the Paleocene-Eocene temperature maximum. During this period, there is an extreme increase in temperature, probably through the massive release of carbon and methane hydrates into the Earth's atmosphere. There is a significant extinction, but not as large as the one at the end of the Cretaceous.

Biosphere

Ecosystems recover in the Paleocene period from the extinction of the K-Pg, which ended the Mesolithic era, and in the first millions of years there were essentially no large creatures weighing more than 100 kilograms. Only about 700,000 years after the catastrophe at the end of the Cretaceous, mammals weighing about 50 kg (eg the genus Ectoconus) appear, as shown by discoveries from the Corall Bluffs site in Colorado, USA. Some scientists have reported several times that small populations of dinosaurs may have survived from the Late Mesozoic to the oldest Paleocene (Grade Dan) as so-called Paleocene dinosaurs, but none of the evidence presented has been sufficiently demonstrable for a long time. But new North American findings suggest such a possibility. But whether the survival time of these d