Tertiary

The Tertiary is a geological period of the Cenozoic before the beginning of the Quaternary. The Tertiary began 65 million years ago ( late Cretaceous period ) and lasted until the beginning of climate change around 2.6 million years ago, which resulted in the Ice Age of the Quaternary an alternation of cold and warm periods brought. The climate on Earth was much warmer than today during the Tertiary. After the mass extinction of large dinosaurs and many other species of animals at the end of the Cretaceous period, developed mainly in the Tertiary the animal and plant world as we know it today.

The term tertiary should be no longer needed within the official geologic time scale. In practice ( in teaching ) but it is still often used. The current convention divides the Tertiary in age two and uses the terms Paleogene for the elderly ( 65.5 to 23.0 mya ) and Neogene for the younger ( 23.0 to 5.3 mya ).

Earlier classification of tertiary

• Above: the last stage of the Upper Cretaceous: Maastrichtian (up to 65 mya )
• Tertiary: Paleocene, 65-58 mya
• Eocene, 58-36 mya
• Oligocene, 36-24 mya
• Miocene, 24-5 mya
• Pliocene, 5 to 2.6 mya

Climate

At the beginning of the Eocene ruled the highest temperatures (30 ° C ) throughout the Cenozoic. The world was free of ice. Due to the plate tectonic shift in the global heat transport has been changed. This resulted in the end of the Eocene to a cooling. In the Oligocene Antarctic glaciation began. In the Miocene, until about 20 million years, Antarctica was completely covered with ice. The northern continents cooled down quickly.

In the Pliocene large parts of the northern continents of ice were covered. The low temperatures ensured an increased body size in animals and a change to savannah vegetation with little forest. In the cold phase, the Earth is today.

Orogeny

Before about 50 million years ago, the Indian continent collided with Asia, causing the Himalayas and the Tibetan Plateau was formed. In addition, tertiary education or the main stages in the formation of the Alps, the Apennines, the Carpathians, the Pyrenees and the Caucasus in Europe and the Andes in South and the Rocky Mountains in North America took place. The formation of mountains in Eurasia have been accompanied by the widespread closure of the Tethys ocean. The central regions of the eastern Mediterranean and the Black Sea are small remnants of this former ocean basin.

Continental drift

Continental drift slowed down significantly in the Tertiary. The former Gondwana broke apart. Australia, which was then bound to the Antarctic, migrated northward. In between, formed a deep oceanic trench. Between North America and Europe or North America and Asia were land bridges. Towards the end of the Tertiary to South America and North America combined its present form.

Fauna and Flora

The Tertiary is the time between the mass extinction at the end of the Cretaceous period, from which also the large dinosaurs were affected, and the beginning of the most recent Ice Age. The extinction could be due to a meteor impact, the so-called KT impact event ( Cretaceous-Tertiary impact ). At the beginning of the period broke mammals from the reptiles as the dominant group of animals. Each epoch of the Tertiary period is marked by characteristic leaps among mammals. The earliest identifiable ancestors of the people who hominoids Proconsul and Australopithecus evolved. The modern forms of birds, reptiles, amphibians, fish and invertebrates were already emerged partly at the beginning of the Tertiary or developed in its course. The plant evolution produced the first angiosperms. The marine animals, however, were subject to - apart from the mammals - only minor evolutionary changes. In the final phase of the Tertiary, the Pliocene, already existed the characteristic of the present forest vegetation in Europe book.

Terminology and Nomenclature

The name comes from the tertiary Historical Geology, ie the description of the earth's history, and was introduced in 1760 by Giovanni Arduino. He distinguished a primary ( basalts, granites, slates ), secondary (fossil calcareous deposits) and tertiary (younger sediments ) due to its epoch observations of geological strata in northern Italy. Although Arduino originally used this tripartite division only to identify different rock formations, the system was soon used as a time grid. 1828, Charles Lyell that name to his own, significantly more accurate system. He divided the Tertiary on the basis of percentages of fossil clam shell finds in the respective layers in the Eocene, Miocene, older and younger Pliocene. However, since this method was suitable only for the investigated region of the Alps and the northern Italian plain, numerous other stratigraphic categories were introduced in the following years until today.

The Tertiary, however, was canceled in 2000 from the internationally accepted and published by the International Commission on Stratigraphy geological time scale. In place of the Tertiary Paleogene occurred (formerly Lower Tertiary ) and the Neogene (formerly Neogene ) as periods in the Cenozoic ( Cenozoic ).

• Cenozoic
• Age of the Cenozoic