Quaternary extinction event
The Quaternary period saw the extinctions of numerous predominantly megafaunal species, which resulted in a collapse in faunal density and diversity and the extinction of key ecological strata across the globe. The most prominent event in the Late Pleistocene is differentiated from previous Quaternary pulse extinctions by the widespread absence of ecological succession to replace these extinct species, the regime shift of established faunal relationships and habitats as a consequence; the earliest casualties were incurred at 130,000 BCE. However, the great majority of extinctions in Afro-Eurasia and the Americas occurred during the transition from the Pleistocene to the Holocene epoch; this extinction wave did not stop at the end of the Pleistocene, continuing on isolated islands, in human-caused extinctions, although there is debate as to whether these should be considered separate events or part of the same event. Among the main causes hypothesized by paleontologists are overkill by the widespread appearance of humans and natural climate change.
A notable modern human presence first appeared during the Middle Pleistocene in Africa, started to establish continuous, permanent populations in Eurasia and Australasia from 120,000 BCE and 63,000 BCE and the Americas from 22,000 BCE. A variant of the former possibility is the second-order predation hypothesis, which focuses more on the indirect damage caused by overcompetition with nonhuman predators. Recent studies have tended to favor the human-overkill theory; the Late Pleistocene extinction event saw the extinction of many mammals weighing more than 40 kg. The proportional rate of megafauna extinctions is progressively larger the greater the human migratory distance from Africa. In Subsaharan Africa, 8 of 50 genera of mammalian megafauna were driven to extinction. In Asia, 24 of 46 In Europe, 23 of 39 In Australasia, 19 of 27 In North America, 45 of 61 In South America, 58 of 71 The extinctions in the Americas entailed the elimination of all the larger mammalian species of South American origin, including those that had migrated north in the Great American Interchange.
Only in the continents of Australia, North America, South America did the extinction occur at family taxonomic levels or higher. The proportional rate of megafauna extinctions being incrementally bigger the larger the migratory distance from Africa might be related to non-African megafauna and Homo sapiens having not evolved as species alongside each other. For their part, North America and South America, which had the highest incremental extinction rates, had no known native species of Hominoidea at all, no species of Hominidae or Homo; the increased rate of extinction mirrors the sequential pattern of the migration of anatomically modern humans. The further away from Africa, the more the area has been inhabited by humans, the less time the environments had had to become accustomed to humans and vice versa. There is no evidence of megafaunal extinctions at the height of the Last Glacial Maximum, indicating that increasing cold and glaciation were not factors. There are three main hypotheses concerning the Pleistocene extinction: climate change associated with the advance and retreat of major ice caps or ice sheets.
"prehistoric overkill hypothesis" the extinction of the woolly mammoth changed the extensive grasslands to birch forests, subsequent forest fires changed the climate. We now know that after the extinction of the mammoth, birch forests replaced the grasslands and that an era of significant fire began. There are some inconsistencies between the current available data and the prehistoric overkill hypothesis. For instance, there are ambiguities around the timing of sudden extinctions of Australian megafauna. Biologists note that comparable extinctions have not occurred in Africa and South or Southeast Asia, where the fauna evolved with hominids. Post-glacial megafaunal extinctions in Africa have been spaced over a longer interval. Evidence supporting the prehistoric overkill hypothesis includes the persistence of certain island megafauna for several millennia past the disappearance of their continental cousins. Ground sloths survived on the Antilles long after North and South American ground sloths were extinct.
The disappearance of the island species correlates with the colonization of these islands by humans. Woolly mammoths died out on remote Wrangel Island 1,000 years after their extinction on the mainland. Steller's sea cows persisted in seas off the isolated and uninhabited Commander Islands for thousands of years after they had vanished from the continental shores of the north Pacific. Alternative hypotheses to the theory of human responsibility include climate change associated with the last glacial period and the Younger Dryas event, as well as Tollmann's hypothetical bolide, which claim that the extinctions resulted from bolide impact; such a scenario has been proposed as a contributing cause of the 1,300-year cold period known as the Younger Dryas stadial. This impact extinction hypothesis is still in debate due to the exacting field techniques required to extract minuscule particles of extraterrestrial impact markers such as iridium at a high resolution from thin strata in a repeatable fashion, as is necessary to conclusively distinguish the event peak from the local background level of the marker.
The debate seems to be exacerbated by infighting between the Uniformitarianism camp and the Catastrophism camp. Recent research indicates that each single species responded differently to environm
South America is a continent in the Western Hemisphere in the Southern Hemisphere, with a small portion in the Northern Hemisphere. It may be considered a subcontinent of the Americas, how it is viewed in the Spanish and Portuguese-speaking regions of the Americas; the reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west on the north and east by the Atlantic Ocean, it includes twelve sovereign states, a part of France, a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands and Tobago, Panama may be considered part of South America. South America has an area of 17,840,000 square kilometers, its population as of 2016 has been estimated at more than 420 million. South America ranks fourth in fifth in population. Brazil is by far the most populous South American country, with more than half of the continent's population, followed by Colombia, Argentina and Peru. In recent decades Brazil has concentrated half of the region's GDP and has become a first regional power.
Most of the population lives near the continent's western or eastern coasts while the interior and the far south are sparsely populated. The geography of western South America is dominated by the Andes mountains. Most of the continent lies in the tropics; the continent's cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the overwhelming majority of South Americans speak Portuguese or Spanish, societies and states reflect Western traditions. South America occupies the southern portion of the Americas; the continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border, although some may consider the border instead to be the Panama Canal. Geopolitically and geographically all of Panama – including the segment east of the Panama Canal in the isthmus – is included in North America alone and among the countries of Central America.
All of mainland South America sits on the South American Plate. South America is home to Angel Falls in Venezuela. South America's major mineral resources are gold, copper, iron ore and petroleum; these resources found in South America have brought high income to its countries in times of war or of rapid economic growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity has hindered the development of diversified economies; the fluctuation in the price of commodities in the international markets has led to major highs and lows in the economies of South American states causing extreme political instability. This is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth. South America is home to many interesting and unique species of animals including the llama, piranha, vicuña, tapir; the Amazon rainforests possess high biodiversity, containing a major proportion of the Earth's species.
Brazil is the largest country in South America, encompassing around half of the continent's land area and population. The remaining countries and territories are divided among three regions: The Andean States, the Guianas and the Southern Cone. Traditionally, South America includes some of the nearby islands. Aruba, Curaçao, Trinidad and the federal dependencies of Venezuela sit on the northerly South American continental shelf and are considered part of the continent. Geo-politically, the island states and overseas territories of the Caribbean are grouped as a part or subregion of North America, since they are more distant on the Caribbean Plate though San Andres and Providencia are politically part of Colombia and Aves Island is controlled by Venezuela. Other islands that are included with South America are the Galápagos Islands that belong to Ecuador and Easter Island, Robinson Crusoe Island, Chiloé and Tierra del Fuego. In the Atlantic, Brazil owns Fernando de Noronha and Martim Vaz, the Saint Peter and Saint Paul Archipelago, while the Falkland Islands are governed by the United Kingdom, whose sovereignty over the islands is disputed by Argentina.
South Georgia and the South Sandwich Islands may be associate
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 419.2 million years ago, to the beginning of the Carboniferous, 358.9 Mya. It is named after Devon, where rocks from this period were first studied; the first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods became well-established. Fish reached substantial diversity during this time, leading the Devonian to be dubbed the "Age of Fishes." The first ray-finned and lobe-finned bony fish appeared, while the placoderms began dominating every known aquatic environment. The ancestors of all four-limbed vertebrates began adapting to walking on land, as their strong pectoral and pelvic fins evolved into legs.
In the oceans, primitive sharks became more numerous than in the Late Ordovician. The first ammonites, species of molluscs, appeared. Trilobites, the mollusc-like brachiopods and the great coral reefs, were still common; the Late Devonian extinction which started about 375 million years ago affected marine life, killing off all placodermi, all trilobites, save for a few species of the order Proetida. The palaeogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, the early formation of the small continent of Euramerica in between; the period is named after Devon, a county in southwestern England, where a controversial argument in the 1830s over the age and structure of the rocks found distributed throughout the county was resolved by the definition of the Devonian period in the geological timescale. The Great Devonian Controversy was a long period of vigorous argument and counter-argument between the main protagonists of Roderick Murchison with Adam Sedgwick against Henry De la Beche supported by George Bellas Greenough.
Murchison and Sedgwick named the period they proposed as the Devonian System. While the rock beds that define the start and end of the Devonian period are well identified, the exact dates are uncertain. According to the International Commission on Stratigraphy, the Devonian extends from the end of the Silurian 419.2 Mya, to the beginning of the Carboniferous 358.9 Mya. In nineteenth-century texts the Devonian has been called the "Old Red Age", after the red and brown terrestrial deposits known in the United Kingdom as the Old Red Sandstone in which early fossil discoveries were found. Another common term is "Age of the Fishes", referring to the evolution of several major groups of fish that took place during the period. Older literature on the Anglo-Welsh basin divides it into the Downtonian, Dittonian and Farlovian stages, the latter three of which are placed in the Devonian; the Devonian has erroneously been characterised as a "greenhouse age", due to sampling bias: most of the early Devonian-age discoveries came from the strata of western Europe and eastern North America, which at the time straddled the Equator as part of the supercontinent of Euramerica where fossil signatures of widespread reefs indicate tropical climates that were warm and moderately humid but in fact the climate in the Devonian differed during its epochs and between geographic regions.
For example, during the Early Devonian, arid conditions were prevalent through much of the world including Siberia, North America, China, but Africa and South America had a warm temperate climate. In the Late Devonian, by contrast, arid conditions were less prevalent across the world and temperate climates were more common; the Devonian Period is formally broken into Early and Late subdivisions. The rocks corresponding to those epochs are referred to as belonging to the Lower and Upper parts of the Devonian System. Early DevonianThe Early Devonian lasted from 419.2 ± 2.8 to 393.3 ± 2.5 and began with the Lochkovian stage, which lasted until the Pragian. It spanned from 410.8 ± 2.8 to 407.6 ± 2.5, was followed by the Emsian, which lasted until the Middle Devonian began, 393.3± 2.7 million years ago. During this time, the first ammonoids appeared. Ammonoids during this time period differed little from their nautiloid counterparts; these ammonoids belong to the order Agoniatitida, which in epochs evolved to new ammonoid orders, for example Goniatitida and Clymeniida.
This class of cephalopod molluscs would dominate the marine fauna until the beginning of the Mesozoic era. Middle DevonianThe Middle Devonian comprised two subdivisions: first the Eifelian, which gave way to the Givetian 387.7± 2.7 million years ago. During this time the jawless agnathan fishes began to decline in diversity in freshwater and marine environments due to drastic environmental changes and due to the increasing competition and diversity of jawed fishes; the shallow, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop such essential characteristics as well developed lungs, the ability to crawl out of the water and onto the land for short periods of time. Late DevonianFinally, the Late Devonian started with the Frasnian, 382.7 ± 2.8 to 372.2 ± 2.5, during which the first forests took shape on land. The first tetrapods appeared in the fossil record in the ensuing Famennian subdivisi
Uruguay the Oriental Republic of Uruguay, is a country in the southeastern region of South America. It borders Argentina to its west and Brazil to its north and east, with the Río de la Plata to the south and the Atlantic Ocean to the southeast. Uruguay is home to an estimated 3.44 million people, of whom 1.8 million live in the metropolitan area of its capital and largest city, Montevideo. With an area of 176,000 square kilometres, Uruguay is geographically the second-smallest nation in South America, after Suriname. Uruguay was inhabited by the Charrúa people for 4,000 years before the Portuguese established Colonia del Sacramento in 1680. Montevideo was founded as a military stronghold by the Spanish in the early 18th century, signifying the competing claims over the region. Uruguay won its independence between 1811 and 1828, following a four-way struggle between Spain and Argentina and Brazil, it remained subject to foreign influence and intervention throughout the 19th century, with the military playing a recurring role in domestic politics.
A series of economic crises put an end to a democratic period that had begun in the early 20th century, culminating in a 1973 coup, which established a civic-military dictatorship. The military government persecuted leftists and political opponents, resulting in several deaths and numerous instances of torture by the military. Uruguay is today a democratic constitutional republic, with a president who serves as both head of state and head of government. Uruguay is ranked first in Latin America in democracy, low perception of corruption, e-government, is first in South America when it comes to press freedom, size of the middle class and prosperity. On a per-capita basis, Uruguay contributes more troops to United Nations peacekeeping missions than any other country, it tops the rank of absence of a unique position within South America. It ranks second in the region on economic freedom, income equality, per-capita income and inflows of FDI. Uruguay is the third-best country on the continent in terms of HDI, GDP growth and infrastructure.
It is regarded as a high-income country by the UN. Uruguay was ranked the third-best in the world in e-Participation in 2014. Uruguay is an important global exporter of combed wool, soybeans, frozen beef and milk. Nearly 95% of Uruguay's electricity comes from renewable energy hydroelectric facilities and wind parks. Uruguay is a founding member of the United Nations, OAS, Mercosur, UNASUR and NAM. Uruguay is regarded as one of the most advanced countries in Latin America, it ranks high on global measures of personal rights and inclusion issues. The Economist named Uruguay "country of the year" in 2013, acknowledging the policy of legalizing the production and consumption of cannabis; the name of the namesake river comes from the Spanish pronunciation of the regional Guarani word for it. There are several interpretations, including "bird-river"; the name could refer to a river snail called uruguá, plentiful in the water. In Spanish colonial times, for some time thereafter and some neighbouring territories were called the Cisplatina and Banda Oriental for a few years the "Eastern Province".
Since its independence, the country has been known as la República Oriental del Uruguay, which means "the eastern republic of the Uruguay ". However, it is translated either as the "Oriental Republic of Uruguay" or the "Eastern Republic of Uruguay"; the documented inhabitants of Uruguay before European colonization of the area were the Charrúa, a small tribe driven south by the Guarani of Paraguay. It is estimated that there were about 9,000 Charrúa and 6,000 Chaná and Guaraní at the time of contact with Europeans in the 1500s. Fructuoso Rivera - Uruguay's first president – organized the Charruas' genocide; the Portuguese were the first Europeans to enter the region of present-day Uruguay in 1512. The Spanish arrived in present-day Uruguay in 1516; the indigenous peoples' fierce resistance to conquest, combined with the absence of gold and silver, limited their settlement in the region during the 16th and 17th centuries. Uruguay became a zone of contention between the Spanish and Portuguese empires.
In 1603, the Spanish began to introduce cattle. The first permanent Spanish settlement was founded in 1624 at Soriano on the Río Negro. In 1669–71, the Portuguese built a fort at Colonia del Sacramento. Montevideo was founded by the Spanish in the early 18th century as a military stronghold in the country, its natural harbor soon developed into a commercial area competing with Río de la Plata's capital, Buenos Aires. Uruguay's early 19th century history was shaped by ongoing fights for dominance in the Platine region, between British, Spanish and other colonial forces. In 1806 and 1807, the British army attempted to seize Buenos Aires and Montevideo as part of the Napoleonic Wars. Montevideo was occupied by a British force from February to September 1807. In 1811, José Gervasio Artigas, who became Uruguay's national hero, launched a successful revolt against the Spanish authorities, defeating them on 18 May at the Battle of Las Piedras. In 1813, the new government in Buenos Aires convened a constituent assembly where Artigas emerged as a champ
The Precambrian is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic eon, named after Cambria, the Latinised name for Wales, where rocks from this age were first studied; the Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons of the geologic time scale, it spans from the formation of Earth about 4.6 billion years ago to the beginning of the Cambrian Period, about 541 million years ago, when hard-shelled creatures first appeared in abundance. Little is known about the Precambrian, despite it making up seven-eighths of the Earth's history, what is known has been discovered from the 1960s onwards; the Precambrian fossil record is poorer than that of the succeeding Phanerozoic, fossils from the Precambrian are of limited biostratigraphic use. This is because many Precambrian rocks have been metamorphosed, obscuring their origins, while others have been destroyed by erosion, or remain buried beneath Phanerozoic strata.
It is thought that the Earth coalesced from material in orbit around the Sun at 4,543 Ma, may have been struck by a large planetesimal shortly after it formed, splitting off material that formed the Moon. A stable crust was in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma; the term "Precambrian" is recognized by the International Commission on Stratigraphy as the only "supereon" in geologic time. "Precambrian" is still used by geologists and paleontologists for general discussions not requiring the more specific eon names. As of 2010, the United States Geological Survey considers the term informal, lacking a stratigraphic rank. A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia. Probable fossils 100 million years older have been found in the same area.
However, there is evidence. There is a solid record of bacterial life throughout the remainder of the Precambrian. Excluding a few contested reports of much older forms from North America and India, the first complex multicellular life forms seem to have appeared at 1500 Ma, in the Mesoproterozoic era of the Proterozoic eon. Fossil evidence from the Ediacaran period of such complex life comes from the Lantian formation, at least 580 million years ago. A diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma; these are referred to as Vendian biota. Hard-shelled creatures appeared toward the end of that time span, marking the beginning of the Phanerozoic eon. By the middle of the following Cambrian period, a diverse fauna is recorded in the Burgess Shale, including some which may represent stem groups of modern taxa; the increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals and other microbes formed prokaryotic mats that covered terrestrial areas.
Tracks from an animal with leg like appendages have been found in what was mud 551 million years ago. Evidence of the details of plate motions and other tectonic activity in the Precambrian has been poorly preserved, it is believed that small proto-continents existed prior to 4280 Ma, that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia, broke up around 750 Ma. A number of glacial periods have been identified going as far back as the Huronian epoch 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a "Snowball Earth"; the atmosphere of the early Earth is not well understood. Most geologists believe it was composed of nitrogen, carbon dioxide, other inert gases, was lacking in free oxygen. There is, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism.
This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis, sometimes called the oxygen catastrophe. At first, oxygen would have combined with other elements in Earth's crust iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides. A terminology has evolved covering the early years of the Earth's existence, as radiometric dating has allowed real dates to be assigned to specific formations and features; the Precambrian is divided into
The Holocene is the current geological epoch. It began 11,650 cal years before present, after the last glacial period, which concluded with the Holocene glacial retreat; the Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as MIS 1, it is considered by some to be an interglacial period within the Pleistocene Epoch. The Holocene has seen the growth and impacts of the human species worldwide, including all its written history, development of major civilizations, overall significant transition toward urban living in the present. Human impacts on modern-era Earth and its ecosystems may be considered of global significance for future evolution of living species, including synchronous lithospheric evidence, or more hydrospheric and atmospheric evidence of human impacts. In July 2018, the International Union of Geological Sciences split the Holocene epoch into three distinct subsections, Greenlandian and Meghalayan, as proposed by International Commission on Stratigraphy.
The boundary stratotype of Meghalayan is a speleothem in Mawmluh cave in India, the global auxiliary stratotype is an ice core from Mount Logan in Canada. The name Holocene comes from the Ancient Greek words ὅλος and καινός, meaning "entirely recent", it is accepted by the International Commission on Stratigraphy that the Holocene started 11,650 cal years BP. The Subcommission on Quaternary Stratigraphy quotes Gibbard and van Kolfschoten in Gradstein Ogg and Smith in stating the term'Recent' as an alternative to Holocene is invalid and should not be used and observe that the term Flandrian, derived from marine transgression sediments on the Flanders coast of Belgium has been used as a synonym for Holocene by authors who consider the last 10,000 years should have the same stage-status as previous interglacial events and thus be included in the Pleistocene; the International Commission on Stratigraphy, considers the Holocene an epoch following the Pleistocene and the last glacial period. Local names for the last glacial period include the Wisconsinan in North America, the Weichselian in Europe, the Devensian in Britain, the Llanquihue in Chile and the Otiran in New Zealand.
The Holocene can be subdivided into five time intervals, or chronozones, based on climatic fluctuations: Preboreal, Atlantic and Subatlantic. Note: "ka" means "kilo-annum" Before Present, i.e. 1,000 years before 1950 The Blytt–Sernander classification of climatic periods defined by plant remains in peat mosses, is being explored. Geologists working in different regions are studying sea levels, peat bogs and ice core samples by a variety of methods, with a view toward further verifying and refining the Blytt–Sernander sequence, they find a general correspondence across Eurasia and North America, though the method was once thought to be of no interest. The scheme was defined for Northern Europe, but the climate changes were claimed to occur more widely; the periods of the scheme include a few of the final pre-Holocene oscillations of the last glacial period and classify climates of more recent prehistory. Paleontologists have not defined any faunal stages for the Holocene. If subdivision is necessary, periods of human technological development, such as the Mesolithic and Bronze Age, are used.
However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world. Climatically, the Holocene may be divided evenly into the Neoglacial periods. According to some scholars, a third division, the Anthropocene, has now begun; the International Commission on Stratigraphy Subcommission on Quaternary Stratigraphy’s working group on the'Anthropocene' note this term is used to denote the present time interval in which many geologically significant conditions and processes have been profoundly altered by human activities. The'Anthropocene' is not a formally defined geological unit. Continental motions due to plate tectonics are less than a kilometre over a span of only 10,000 years. However, ice melt caused world sea levels to rise about 35 m in the early part of the Holocene. In addition, many areas above about 40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as 180 m due to post-glacial rebound over the late Pleistocene and Holocene, are still rising today.
The sea level rise and temporary land depression allowed temporary marine incursions into areas that are now far from the sea. Holocene marine fossils are known, from Vermont and Michigan. Other than higher-latitude temporary marine incursions associated with glacial depression, Holocene fossils are found in lakebed and cave deposits. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during the period exceeds any tectonic uplift of non-glacial origin. Post-glacial rebound in the Scandinavia region resulted in the formation of the Baltic Sea; the region continues to rise, still causing weak earthquakes across Northern Europe. The equivalent event in North America was the rebound of Hudson Bay, as it shrank from its larger, immediate post-glacial Tyrrell Sea phase, to near its present boundaries. Climate has been stable over the Holocene. Ice core
The Brazilian Highlands or Brazilian Plateau are an extensive geographical region, covering most of the eastern and central portions of Brazil, in all half of the country's land area, or some 4,500,000 km2. In addition, the vast majority of Brazil's population lives in the highlands or on the narrow coastal region adjacent to it. Ancient basaltic lava flows gave birth to much of the region. However, the time of dramatic geophysical activity is long past, as there is now no seismic or volcanic activity. Erosion has played a large part in shaping the Highlands, forming extensive sedimentary deposits and wearing down the mountains; the Brazilian Highlands are recognized for the great diversity to be found there: within the region there are several different biomes, vastly different climatic conditions, many types of soil, thousands of animal and plant species. Due to their size and diversity, the Brazilian Highlands are divided into three main areas: Atlantic Plateau, extending all along the eastern coast of Brazil, including several mountain ranges.
It was once completely covered by the Atlantic Rainforest, one of the richest areas of biodiversity in the world, of which only 7.3% remains. Southern Plateau, advancing inland in the southern and southern-central portions of the country. Sedimentary rocks covered by basaltic lava spills that form the fertile ground known as "purple land". Large portions of this region were covered by the Atlantic Rainforest, while araucaria highland forest and cerrado grasslands took up much of the rest. Central Plateau, occupying the central portions of Brazil, with sedimentary and crystalline formations. 85% was once covered by cerrado vegetation, of which only a small portion remains intact. In addition to the plateau regions, several adjoining or enclosed mountain ranges are considered to be part of the Brazilian Highlands; some of the most important are: Serra da Borborema Chapada Diamantina Serra do Espinhaço Serra do Caparaó Serra da Mantiqueira Serra do Mar Serra GeralThe highest point of the Brazilian Highlands is the Pico da Bandeira in the Serra do Caparaó, 2,891 meters.
Plateaus of Brazil Guiana Shield Serras de Sudeste