We explain what the Quaternary Period was, how it is divided and the climate it presents. Also, what are its characteristics, flora and fauna.

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Human beings appeared in the Quaternary Period.

What was the Quaternary period?

On the geological time scale, the Quaternary period is the last temporal division of the Cenozoic Era (started 66 million years ago and extends to the present). It began 2.59 million years ago, when the Neogene culminated, and extends to the present, or until the beginning of the history of human civilization.

Perhaps because it is relatively recent, it is the most and best studied period of geological history of all, since their footprints, fossils and substrates can be found without difficulty near the Earth’s surface and on the seabed. In this period appeared the Homo sapiens on earth.

The name “Quaternary” was given to it in 19th century France by geologist Jules Desnoyers, when an outdated method of nomenclature was used for geological layers. It is also known as the Anthropozoic Era.since it is the era in which the human being appears.

See also: Geological eras

Previous period

Formerly The first part of the Cenozoic Era was called the Tertiary period.from the extinction of the dinosaurs to the rise of the first hominins in the ice ages.

At present, the study of the first part of the Cenozoic Era is preferred. separated into two periods: Paleogene and Neogene.

In this period the world was geologically reorganized until it reached the configuration we know today.

It was a stage of resurgence and diversification of organisms. Mammals were the predominant new life formfinding the free field to proliferate and multiply.

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Quaternary Division

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The Pleistocene begins about 2.5 million years ago and ends about 126,000 years ago.

The Quaternary period is divided into two distinct eras:

  • Pleistocene. It begins about 2.5 million years ago and culminates about 126,000 years ago, spanning four different ages: the Gelasian, the Calabrian, the Ionian (or Middle Pleistocene) and the Tarantian (or Upper or Late Pleistocene).
  • Holocene. It begins approximately 12,000 years ago, and extends until the emergence of human civilization, without dividing into any age.

Geological features of the Quaternary

The configuration of the continents varied very little throughout the Quaternary, in numbers that are practically negligible by paleontology (barely 100km). However, the marks of these transitions are much better preserved than any past era.

The largest variations have to do with rise and fall of sea level. It was caused by the glacial and interglacial periods, which, by expanding or diminishing the ice cap at the poles, consumed or released quantities of ocean water.

For these variations, various continental platforms emerged or disappeared under the surface of the watersuch as the Bering Strait, the union of the islands of Indonesia, New Guinea, Japan and Taiwan, the union of Australia with New Zealand and Tasmania, or the transformation, due to lowering of the sea level, of the Black Sea and the Baltic Sea in freshwater lakes.

Quaternary climate

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During the ice ages, the ice expanded and the global climate cooled.

The climate during the Quaternary also governed by glacial and interglacial patterns. It alternated between temperatures 4 to 5 °C below today’s in surface ocean waters, and another 1 to 2 °C above modern temperatures.

It is estimated that During the Pleistocene there was an El Niño phenomenon.with trade winds in the South Pacific, warm air in Peru, and warm ocean currents from the western Pacific and Indian Oceans to the eastern Pacific.

Glaciation or “Ice Ages”

Traditionally, the Quaternary was understood as a period of fluctuations in the ice level in the polar regionsin more or less stable cycles ranging from 100,000 years.

According to this theory, around 80 glaciations were estimated throughout the period, generating glacial periods or “ice ages” in which the ice expanded, the seas receded and the global climate cooled. In interglacial periods, the cold decreased, the heat increased, and the ice receded, releasing water into the oceans.

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Although this theory is currently being questioned, it was traditionally accepted that ice age cycles were repeated. In the last million years, 4 main major glaciations occurred, with their respective intermediate periods:

  • Günz glaciation (1.1 million years ago)
  • Mindel glaciation (580,000 years ago)
  • Riss glaciation (200,000 years ago)
  • Würm glaciation (80,000 years).

Flora in the Quaternary

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Mixed environments appeared during the Quaternary period.

The Quaternary flora shows, judging by the fossils found, species similar to those we know today. Climatic stress pushed species into greater ranges of adaptation.

On the other hand, the appearance of mixed environments, half tundra and prairie, for example, created new evolutionary competencies. No equivalent to these mixed environments still exists.

Fauna in the Quaternary

90% of the animal fossils found come from the Quaternary have a high resemblance to their known modern species. In other words, there was minimal variation in the successful evolutionary forms during the transition from the Pleistocene to today.

Most of the large species, almost entirely mammals, They adapted to the climate of the regions in which they lived.especially during ice ages. Large carnivores such as Saber-toothed Tigers or herbivores such as Woolly Mammoths, bison and other long-haired animals predominated.

Just like insects during the Mesozoic, mammals enjoyed enormous size during the Pleistocene. The reasons for this are unknown, but the modern descendants of the creatures of that time are much more modest in size.

There was also an important alternation between the American (and especially South American) species and those of the rest of the world, given the prolonged isolation that they lived, especially in the periods of higher sea level, in which the continent became an island. This led to an increase in biodiversity that holds up to this day.

At the end of the ice ages, many species suffered localized extinctions, in which the intervention of primitive human beings, active group hunters, is not ruled out towards the end of the Pleistocene. Such extinctions continued into the Holocene, indisputably due to human action.

human evolution

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The first hominins arose on the African continent.

One of the most important elements of the quaternary is the appearance of humanity. This was the result of a slow process of biological changes.

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The first hominins arose on the continent African. Species of the genus australopithecus and subsequently Homomigrated from the continent to Eurasia and the Near East, thus giving rise to new human species.

The last three of these species were the homo neanderthalensis (“Neanderthal Man”), Homo denisovensis (“Denisova hominid”) and, of course, the Homo sapiensthe only species not extinct today and what we now understand as “Humanity”.

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Quaternary deposits

The vast majority of contemporary floors They are nourished by deposits from the Quaternary, the result of extinct glacial lakes, deposits of biological sediments, etc. It was these deposits that form the river plains and deltas of the Missouri, Mississippi (USA), Huang He and Yangtze (China) rivers, as well as the Rhine Valley in Europe.

Similarly, these deposits are a source of groundwater and high value mineralssuch as gold and diamond deposits, such as those that sparked the California “gold rush” in the United States in 1849, and are still mined in Alaska and other regions.

human history

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Prehistory is the stage prior to the invention of writing.

The history of our species Starts about 10,000 years ago, unequally depending on the different known “cradles” of civilization. It is usually linked to the appearance of the first human settlements, with the discovery of agriculture, construction and the forging of metals.

Other theories identify certain cultural elements as the minimum to start talking about “humanity”, such as ritual burial, the prohibition of incest and the beginning of narratives (religious-epic at the beginning, commonly).

In any way, This History includes a first part called “prehistory” (before the invention of writing). A second part leads to the present of our civilization (from the systematization of writing).

References:

  • “Quaternary Period” on Wikipedia.
  • “Quaternary Period, Characteristics, Life and Fauna” in History and Biographies.
  • “Hominization Process III – Quaternary Period” (video) in Educatina.
  • “Quaternary period: Climate, Animals & Other Facts” in Live Science.
  • “Quaternary Period” in National Geographic.
  • “Quaternary” in The Encyclopaedia Britannica.

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