Mesozoic era is considered as a transitional stage in the development of the planet.Some geologists call it "biological and geological Middle Ages."
Mesozoic era began at the end of Variscan (Variscan) of mountain-building processes, and ended - with the start of the Alpine orogeny (the last major tectonic revolution).
In the Southern Hemisphere, ended a split of the ancient continent of Gondwana.In general, life in the Mesozoic era characterized by relative calm.The processes of mountain building were rare and short-lived.
Mesozoic Era lasted approximately 160 million. Years.
From a biological point of view, this era is a time of transition from the primitive to the old forms more progressive new.The world at that time was much more varied than in the Paleozoic, and the flora and fauna have been significantly upgraded.
Mesozoic Era.Periods
There are three stages in this era.
first - Triassic - so named because of the fact that his deposits ranked among three different set of rocks.These include neyper - upper limestone - the average continental sandstone - lower.The most typical are the sand-clay continental rocks (often with coal lenses), shale, marine limestone, gypsum, salt, lagoons anhydride.
In the Triassic period there was a connection southern continent (Gondwana) from the northern continent (Laurasia).Along with these changes in the distribution of land and sea, mountain building, the formation of new volcanic areas, took place quite rapidly and updating of flora and fauna.However, only a few species have moved from the Paleozoic to Mesozoic.According to the researchers, all of these factors are the result of large-scale disasters occurred on the border of eras.
next stage, which includes the Mesozoic era - the Jurassic.It began about 200, and ended about 145.5 million. Years ago.Jurassic became one of the most famous periods in the development of the planet.
At this time, the most widely used among the plants received the gymnosperms and ferns.It is assumed that environmental conditions were similar to the terms of the Carboniferous period, as noted extensive char formation.Exist in the Permian, Triassic began to crack in the system of a huge continent continued to decay.This process has a significant impact on ocean currents, rainfall, climate and living conditions of the whole organism.
Jurassic considered "reptiles of time."The land was inhabited by dinosaurs.In the seas lived plesiosaurs and ichthyosaurs, in the air - the pterosaurs.Among the dinosaurs began to form a giant species.At the same time there were small insectivorous pterodactyls.At the end of the Jurassic period, it began the accumulation of powerful layered layers limestone - chalk.Thus, a new stage.
Home Cretaceous period characterized by some major event in the formation of the organic world.At this time began to appear the first flowering plants, fossils of which are presented in wood and rocks leaves, growing and today (for example, elm, oak, willow, maple).The fauna in the Cretaceous period is generally similar to that developed in the Jurassic period.
end of this phase was characterized by intense orogeny (mountain building) in East Asia, North and South America.Sedimentary rocks collected in the Andean geosyncline during several periods, sealed and crumpled into folds.Thus, the Andes were formed.
In many areas of the planet has increased volcanic activity.The entire southern part of the Indian subcontinent was covered with lava (so large plateau formed "Dean").At the end of the Mesozoic era on all continents were significant uplift.
