The last geological and now reachingThe Quaternary period was singled out in 1829 by the scientist Jules Denoyer. In Russia, it is also called anthropogenic. The geologist Alexey Pavlov became the author of this name in 1922. With his initiative, he wanted to emphasize that it is this period that is associated with the appearance of man.
По сравнению с другими геологическими периодами the Quaternary period has a very short duration (only 1.65 million years). Continuing today, it remains unfinished. Another feature is the presence of remnants of human culture in Quaternary sediments. This period is characterized by repeated and abrupt climatic changes, which radically influenced natural conditions.
Periodically repeated cooling ledglaciation of northern latitudes and low latitude moistening. Warming caused exactly the opposite effect. The sedimentary formations of the last millennia are distinguished by the complex structure of the section, the relative short duration of formation, and the diversity of layers. The Quaternary period is divided into two epochs (or divisions): the Pleistocene and the Holocene. The border between them lies at the mark of 12 thousand years ago.
From its very beginning, the Quaternary periodcharacterized by close to the modern plant and animal world. Changes in this fund are entirely dependent on a series of cooling and warming. With the onset of glaciation, cold-loving species migrated to the south and mixed with strangers. During periods of increasing average temperatures, the reverse process occurred. At this time, the area of settling of moderately warm, subtropical and tropical flora and fauna expanded greatly. For some time, entire tundra associations of the organic world disappeared.
Флоре пришлось несколько раз приспосабливаться к radically changing conditions of existence. Many of the cataclysms during this time marked the Quaternary period. Climate swings led to the impoverishment of broadleaf and evergreen forms, as well as the expansion of the range of grassy species.
The most notable changes in the animal worldaffected mammals (especially the ungulates and proboscis of the Northern Hemisphere). In the Pleistocene, due to sharp climatic leaps, many heat-loving species became extinct. At the same time, for the same reason, new animals appeared, better adapted to life in harsh natural conditions. The extinction of fauna reached its peak during the Dnieper glaciation (300 - 250 thousand years ago). At the same time, the cooling determined the formation of a platform cover in the Quaternary.
At the end of the Pliocene, the south of Eastern Europe was homefor mastodons, southern elephants, hipparions, saber-toothed tigers, Etruscan rhinos, etc. Ostriches and hippos lived in the West of the Old World. However, in the early Pleistocene, the animal world began to change radically. With the onset of the Dnieper glaciation, many heat-loving species moved to the south. In the same direction the area of flora distribution shifted. The Cenozoic era (the Quaternary period in particular) tested all forms of life for strength.
On the southern borders of the glacier, suchSpecies like the mammoth, woolly rhinoceros, reindeer, musk ox, lemmings, white partridges. All of them lived exclusively in cold areas. Cave lions, bears, hyenas, giant rhinos and other heat-loving before living in these regions have become extinct.
The cold climate was established in the Caucasus, in the Alps,Carpathians and Pyrenees, which forced many species to leave the highlands and settle in the valleys. Woolly rhinos and mammoths occupied even Southern Europe (not to mention the whole of Siberia, from where they came to North America). The relict fauna of Australia, South America, South and Central Africa has been preserved thanks to its own isolation from the rest of the world. Mammoths and other animals, well adapted to the conditions of the harsh climate, died out at the beginning of the Holocene. It is worth noting that despite the numerous glaciations, about 2/3 of the Earth's surface has never been affected by the ice cap.
As mentioned above, a variety ofdefinitions of the Quaternary period can not do without the "man-made". The rapid development of man is the most important event of this entire historical segment. The place of appearance of the most ancient people today is East Africa.
Ancestral form of modern man -Australopithecus, belonging to the hominid family. According to various estimates, they first appeared in Africa 5 million years ago. Gradually, Australopithecus became erect and omnivorous. About 2 million years ago they learned how to make primitive tools. So there was a skillful man. A million years ago, Pithecanthropes were formed, the remains of which are found in Germany, Hungary and China.
350 тысяч лет назад появились палеоантропы (или Neanderthals), extinct 35 thousand years ago. Traces of their activity were found in the southern and temperate latitudes of Europe. Paleoanthropines have been replaced by modern humans (neoanthropes or homo sapines). They first penetrated into America and Australia, and also colonized the numerous islands of several oceans.
Already the earliest neoanthropes are almost nothingdifferent from today's people. They adapted well and quickly to climate change and skillfully learned how to process a stone. These hominids acquired bone products, primitive musical instruments, objects of fine art, and ornaments.
Quaternary period in the south of Russia leftnumerous archaeological sites related to neoanthropes. However, they traveled to the most northern regions. Cooling people learned to worry with the help of fur clothing and fires. Therefore, for example, the Quaternary period of Western Siberia was also marked by the expansion of people trying to develop new territories. 5 thousand years ago, the Bronze Age began, 3 thousand years ago - the Iron Age. At the same time in Mesopotamia, Egypt and the Mediterranean, the centers of ancient civilization were born.
Scientists have divided into several groups of usefulfossils, which left us a Quaternary period. The sediments of the last millennia belong to various placers, non-metallic and combustible materials, ores of sedimentary origin. Coastal-sea and alluvial deposits are known. The most important minerals of the Quaternary period: gold, diamonds, platinum, cassiterite, ilmenite, rutile, zircon.
In addition, ironores of lake and bog origin. Manganese and copper-vanadium deposits can be attributed to this group. Such clusters are common in the oceans.
Даже сегодня продолжают выветриваться equatorial and tropical rocks of the Quaternary. As a result of this process, laterite is formed. A similar formation is covered with aluminum and iron and is an important African mineral. Metalliferous bark of the same latitude is rich in deposits of nickel, cobalt, copper, manganese, and refractory clays.
In the Quaternary, importantnon-metallic minerals. These are gravels (commonly used in construction) for molding and glass sands, potash and rock salts, sulfur, borates, peat, and lignite. Quaternary sediments contain groundwater, which is the main source of clean drinking water. Do not forget about the permafrost and ice. In general, the last geological period remains the crown of the geological evolution of the Earth, which began more than 4.5 billion years ago.
