Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to pressure, causing profound physical or chemical change; the protolith may be igneous, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface, they are classified by chemical and mineral assemblage. They may be formed by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it, they can form from tectonic processes such as continental collisions, which cause horizontal pressure and distortion. They are formed when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior; the study of metamorphic rocks provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss, marble and quartzite.
Metamorphic minerals are those that form only at the high temperatures and pressures associated with the process of metamorphism. These minerals, known as index minerals, include sillimanite, staurolite and some garnet. Other minerals, such as olivines, amphiboles, micas and quartz, may be found in metamorphic rocks, but are not the result of the process of metamorphism; these minerals formed during the crystallization of igneous rocks. They are stable at high temperatures and pressures and may remain chemically unchanged during the metamorphic process. However, all minerals are stable only within certain limits, the presence of some minerals in metamorphic rocks indicates the approximate temperatures and pressures at which they formed; the change in the particle size of the rock during the process of metamorphism is called recrystallization. For instance, the small calcite crystals in the sedimentary rock limestone and chalk change into larger crystals in the metamorphic rock marble. Both high temperatures and pressures contribute to recrystallization.
High temperatures allow the atoms and ions in solid crystals to migrate, thus reorganizing the crystals, while high pressures cause solution of the crystals within the rock at their point of contact. The layering within metamorphic rocks is called foliation, it occurs when a rock is being shortened along one axis during recrystallization; this causes the platy or elongated crystals of minerals, such as mica and chlorite, to become rotated such that their long axes are perpendicular to the orientation of shortening. This results in a banded, or foliated rock, with the bands showing the colors of the minerals that formed them. Textures are separated into non-foliated categories. Foliated rock is a product of differential stress that deforms the rock in one plane, sometimes creating a plane of cleavage. For example, slate is a foliated metamorphic rock. Non-foliated rock does not have planar patterns of strain. Rocks that were subjected to uniform pressure from all sides, or those that lack minerals with distinctive growth habits, will not be foliated.
Where a rock has been subject to differential stress, the type of foliation that develops depends on the metamorphic grade. For instance, starting with a mudstone, the following sequence develops with increasing temperature: slate is a fine-grained, foliated metamorphic rock, characteristic of low grade metamorphism, while phyllite is fine-grained and found in areas of low grade metamorphism, schist is medium to coarse-grained and found in areas of medium grade metamorphism, gneiss coarse to coarse-grained, found in areas of high-grade metamorphism. Marble is not foliated, which allows its use as a material for sculpture and architecture. Another important mechanism of metamorphism is that of chemical reactions that occur between minerals without them melting. In the process atoms are exchanged between the minerals, thus new minerals are formed. Many complex high-temperature reactions may take place, each mineral assemblage produced provides us with a clue as to the temperatures and pressures at the time of metamorphism.
Metasomatism is the drastic change in the bulk chemical composition of a rock that occurs during the processes of metamorphism. It is due to the introduction of chemicals from other surrounding rocks. Water may transport these chemicals over great distances; because of the role played by water, metamorphic rocks contain many elements absent from the original rock, lack some that were present. Still, the introduction of new chemicals is not necessary for recrystallization to occur. Contact metamorphism is the name given to the changes that take place when magma is injected into the surrounding solid rock; the changes that occur are greatest wherever the magma comes into contact with the rock because the temperatures are highest at this boundary and decrease with distance from it. Around the igneous rock that forms from the cooling magma is a metamorphosed zone called a contact metamorphism aureole. Aureoles may show all degrees of metamorphism from the contact area to unmetamorphosed country rock some distance away.
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North America is a continent within the Northern Hemisphere and all within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, to the southeast by South America and the Caribbean Sea. North America covers an area of about 24,709,000 square kilometers, about 16.5% of the earth's land area and about 4.8% of its total surface. North America is the third largest continent by area, following Asia and Africa, the fourth by population after Asia and Europe. In 2013, its population was estimated at nearly 579 million people in 23 independent states, or about 7.5% of the world's population, if nearby islands are included. North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge 40,000 to 17,000 years ago; the so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago. The Classic stage spans the 6th to 13th centuries.
The Pre-Columbian era ended in 1492, the transatlantic migrations—the arrival of European settlers during the Age of Discovery and the Early Modern period. Present-day cultural and ethnic patterns reflect interactions between European colonists, indigenous peoples, African slaves and their descendants. Owing to the European colonization of the Americas, most North Americans speak English, Spanish or French, their culture reflects Western traditions; the Americas are accepted as having been named after the Italian explorer Amerigo Vespucci by the German cartographers Martin Waldseemüller and Matthias Ringmann. Vespucci, who explored South America between 1497 and 1502, was the first European to suggest that the Americas were not the East Indies, but a different landmass unknown by Europeans. In 1507, Waldseemüller produced a world map, in which he placed the word "America" on the continent of South America, in the middle of what is today Brazil, he explained the rationale for the name in the accompanying book Cosmographiae Introductio:... ab Americo inventore... quasi Americi terram sive Americam.
For Waldseemüller, no one should object to the naming of the land after its discoverer. He used the Latinized version of Vespucci's name, but in its feminine form "America", following the examples of "Europa", "Asia" and "Africa". Other mapmakers extended the name America to the northern continent, In 1538, Gerard Mercator used America on his map of the world for all the Western Hemisphere; some argue that because the convention is to use the surname for naming discoveries, the derivation from "Amerigo Vespucci" could be put in question. In 1874, Thomas Belt proposed a derivation from the Amerrique mountains of Central America. Marcou corresponded with Augustus Le Plongeon, who wrote: "The name AMERICA or AMERRIQUE in the Mayan language means, a country of perpetually strong wind, or the Land of the Wind, and... the can mean... a spirit that breathes, life itself." The United Nations formally recognizes "North America" as comprising three areas: Northern America, Central America, The Caribbean.
This has been formally defined by the UN Statistics Division. The term North America maintains various definitions in accordance with context. In Canadian English, North America refers to the land mass as a whole consisting of Mexico, the United States, Canada, although it is ambiguous which other countries are included, is defined by context. In the United States of America, usage of the term may refer only to Canada and the US, sometimes includes Greenland and Mexico, as well as offshore islands. In France, Portugal, Romania and the countries of Latin America, the cognates of North America designate a subcontinent of the Americas comprising Canada, the United States, Mexico, Greenland, Saint Pierre et Miquelon, Bermuda. North America has been referred to by other names. Spanish North America was referred to as Northern America, this was the first official name given to Mexico. Geographically the North American continent has many subregions; these include cultural and geographic regions. Economic regions included those formed by trade blocs, such as the North American Trade Agreement bloc and Central American Trade Agreement.
Linguistically and culturally, the continent could be divided into Latin America. Anglo-America includes most of Northern America and Caribbean islands with English-speaking populations; the southern North American continent is composed of two regions. These are the Caribbean; the north of the continent maintains recognized regions as well. In contrast to the common definition of "North America", which encompasses the whole continent, the term "North America" is sometimes used to refer only to Mexico, the United States, Greenland; the term Northern America refers to the northern-most countries and territories of North America: the United States, Bermuda, St. Pierre and Miquelon and Greenland. Although the term does not refer to a unifie
The Allegheny Plateau, in the United States, is a large dissected plateau area in western and central New York and western Pennsylvania and western West Virginia, eastern Ohio. It is divided into the glaciated Allegheny Plateau; the plateau extends southward into western West Virginia, eastern Kentucky and Tennessee where it is instead called the Cumberland Plateau. The plateau terminates in the east at the Allegheny Mountains, which are the highest ridges just west of the Allegheny Front; the Front extends from central Pennsylvania into eastern West Virginia. The plateau is bordered on the west by glacial till plains in the north north of the Ohio River, the Bluegrass region in the south south of the Ohio River. Elevations vary greatly. In the glaciated Allegheny Plateau, relief may only reach one hundred feet or less. In the unglaciated Allegheny Plateau in southeastern Ohio and westernmost West Virginia, relief is in the range of two hundred to four hundred feet. Absolute highest elevations in this area are in the range of 900 to 1,500 feet.
By the Allegheny Front, elevations may reach well over 4,000 feet, with relief of up to 2,000 feet. The Allegheny Plateau is a physiographic section of the larger Appalachian Plateau province, which in turn is part of the larger Appalachian physiographic division. Allegheny Front, the transition escarpment from the Allegheny Plateau to the Ridge-and-Valley Appalachians Ridge-and-Valley Appalachians Faill, Rodger T.. "A Geologic History of the North-Central Appalachians, Part 1: Orogenesis from the Mesoproterozoic through the Taconic Orogeny". American Journal of Science. 297: 551–619. Doi:10.2475/ajs.297.6.551. Faill, Rodger T.. "A Geologic History of the North-Central Appalachians, Part 2: The Appalachian Basin from the Silurian through the Carboniferous". American Journal of Science. 297: 729–761. Doi:10.2475/ajs.297.7.729. Faill, Rodger T.. "A Geologic History of the North-Central Appalachians, Part 3: The Alleghany Orogeny". American Journal of Science. 298: 131–179. Doi:10.2475/ajs.298.2.131. Photographs of the Allegheny Plateau and the Allegheny River watershed region Media related to Allegheny Plateau at Wikimedia Commons
Russia the Russian Federation, is a transcontinental country in Eastern Europe and North Asia. At 17,125,200 square kilometres, Russia is by far or by a considerable margin the largest country in the world by area, covering more than one-eighth of the Earth's inhabited land area, the ninth most populous, with about 146.77 million people as of 2019, including Crimea. About 77 % of the population live in the European part of the country. Russia's capital, Moscow, is one of the largest cities in the world and the second largest city in Europe. Extending across the entirety of Northern Asia and much of Eastern Europe, Russia spans eleven time zones and incorporates a wide range of environments and landforms. From northwest to southeast, Russia shares land borders with Norway, Estonia, Latvia and Poland, Ukraine, Azerbaijan, China and North Korea, it shares maritime borders with Japan by the Sea of Okhotsk and the U. S. state of Alaska across the Bering Strait. However, Russia recognises two more countries that border it, Abkhazia and South Ossetia, both of which are internationally recognized as parts of Georgia.
The East Slavs emerged as a recognizable group in Europe between the 3rd and 8th centuries AD. Founded and ruled by a Varangian warrior elite and their descendants, the medieval state of Rus arose in the 9th century. In 988 it adopted Orthodox Christianity from the Byzantine Empire, beginning the synthesis of Byzantine and Slavic cultures that defined Russian culture for the next millennium. Rus' disintegrated into a number of smaller states; the Grand Duchy of Moscow reunified the surrounding Russian principalities and achieved independence from the Golden Horde. By the 18th century, the nation had expanded through conquest and exploration to become the Russian Empire, the third largest empire in history, stretching from Poland on the west to Alaska on the east. Following the Russian Revolution, the Russian Soviet Federative Socialist Republic became the largest and leading constituent of the Union of Soviet Socialist Republics, the world's first constitutionally socialist state; the Soviet Union played a decisive role in the Allied victory in World War II, emerged as a recognized superpower and rival to the United States during the Cold War.
The Soviet era saw some of the most significant technological achievements of the 20th century, including the world's first human-made satellite and the launching of the first humans in space. By the end of 1990, the Soviet Union had the world's second largest economy, largest standing military in the world and the largest stockpile of weapons of mass destruction. Following the dissolution of the Soviet Union in 1991, twelve independent republics emerged from the USSR: Russia, Belarus, Uzbekistan, Azerbaijan, Kyrgyzstan, Tajikistan and the Baltic states regained independence: Estonia, Lithuania, it is governed as a federal semi-presidential republic. Russia's economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2018. Russia's extensive mineral and energy resources are the largest such reserves in the world, making it one of the leading producers of oil and natural gas globally; the country is one of the five recognized nuclear weapons states and possesses the largest stockpile of weapons of mass destruction.
Russia is a great power as well as a regional power and has been characterised as a potential superpower. It is a permanent member of the United Nations Security Council and an active global partner of ASEAN, as well as a member of the Shanghai Cooperation Organisation, the G20, the Council of Europe, the Asia-Pacific Economic Cooperation, the Organization for Security and Co-operation in Europe, the World Trade Organization, as well as being the leading member of the Commonwealth of Independent States, the Collective Security Treaty Organization and one of the five members of the Eurasian Economic Union, along with Armenia, Belarus and Kyrgyzstan; the name Russia is derived from Rus', a medieval state populated by the East Slavs. However, this proper name became more prominent in the history, the country was called by its inhabitants "Русская Земля", which can be translated as "Russian Land" or "Land of Rus'". In order to distinguish this state from other states derived from it, it is denoted as Kievan Rus' by modern historiography.
The name Rus itself comes from the early medieval Rus' people, Swedish merchants and warriors who relocated from across the Baltic Sea and founded a state centered on Novgorod that became Kievan Rus. An old Latin version of the name Rus' was Ruthenia applied to the western and southern regions of Rus' that were adjacent to Catholic Europe; the current name of the country, Россия, comes from the Byzantine Greek designation of the Rus', Ρωσσία Rossía—spelled Ρωσία in Modern Greek. The standard way to refer to citizens of Russia is rossiyane in Russian. There are two Russian words which are commonly
Valles Caldera is a 13.7-mile wide inactive volcanic caldera in the Jemez Mountains of northern New Mexico. Hot springs, fumaroles, natural gas seeps and volcanic domes dot the caldera floor landscape; the highest point in the caldera is Redondo Peak, an 11,253-foot resurgent lava dome located within the caldera. Within the caldera are several grass valleys the largest of, Valle Grande, the only one accessible by a paved road. Much of the caldera is within the Valles Caldera National Preserve, a unit of the National Park System. In 1975, Valles Caldera was designated as a National Natural Landmark by the National Park Service. Use of Valles Caldera dates back to the prehistoric times: spear points dating to 11,000 years ago have been discovered. Several Native American tribes frequented the caldera seasonally for hunting and for obsidian, used for spear and arrow points. Obsidian from the caldera was traded by tribes across much of the Southwest. Spanish and Mexican settlers as well as the Navajo and other tribes came to the caldera seasonally for grazing with periodic clashes and raids.
As the United States acquired New Mexico as part of the Treaty of Guadalupe Hidalgo in 1848, the caldera became the backdrop for the Indian wars with the U. S. Army. Around the same time, the commercial use of the caldera for ranching, its forest for logging began; the caldera became part of the Baca Ranch in 1876. The Bacas were a wealthy family given the land as compensation for the termination of a grant given to their family near Las Vegas, in northeastern New Mexico; the family was given several other parcels including one in Arizona. This area, 100,000 acres, was called Baca Location number one. Since the land has been through a string of exchanges between private owners and business enterprises. Most notably, it was owned by Frank Bond in the 1930s. Mr. Bond, a businessman based in nearby Española, ran up to 30,000 sheep in the calderas overgrazing the land and causing damage from which the watersheds of the property are still recovering; the land was purchased by the Dunigan family from Abilene, Texas in 1963.
Pat Dunigan did not obtain the timber rights and the New Mexico Lumber Company logged the property heavily, leaving the land scarred with roads and removing significant amounts of old-growth douglas fir and ponderosa pine. Mr. Dunigan slowed the logging, he negotiated unsuccessfully with the National Park Service and the US Forest Service for possible sale of the property in the 1980s. The Valles Caldera Preservation Act of 2000 signed by President Clinton on July 25, 2000, created the Valles Caldera National Preserve; the legislation provided for the federal purchase of this historical ranch nestled inside a volcanic caldera, with funds coming from the Land and Water Conservation Fund derived from royalties the US government receives from offshore petroleum and natural gas drilling. The Dunigan family sold the entire surface estate of 95,000 acres and seven-eighths of the geothermal mineral estate to the federal government for $101 million; as some sites of the Baca Ranch are sacred and of cultural significance to the Native Americans, 5,000 acres of the purchase were obtained by the Santa Clara Pueblo, which borders the property to the northeast.
This include the headwaters of Santa Clara Creek, sacred to the pueblo. On the southwest corner of the land 300 acres were to be ceded to Bandelier National Monument. In July 2011, the Las Conchas Fire started by a power line on nearby private land, burning 30,000 acres of the Valles Caldera National Preserve; the wildfire burned a total of 158,000 acres in the Jemez Mountains, including most of neighboring Bandelier National Monument. The circular topographic rim of the caldera measures 13.7 miles in diameter. The caldera and surrounding volcanic structures are one of the most studied caldera complexes in the United States. Research studies have concerned the fundamental processes of magmatism, hydrothermal systems, ore deposition. Nearly 40 deep cores have been examined. Valles Caldera is the younger of two calderas known at this location, having collapsed over and buried the older Toledo Caldera, which in turn may have collapsed over yet older calderas; the associated Cerros del Rio volcanic field, which forms the eastern Pajarito Plateau and the Caja del Rio, is older than the Toledo Caldera.
The Toledo and Valles Calderas formed during eruptions 1.61 million and 1.2 million years ago, respectively. The caldera forming Toledo eruption formed the Otowi member of the Bandelier Tuff at 1.61 million years ago, which can be seen along canyon walls west of Valles Caldera, including San Diego Canyon. The younger Tshirege member of the Bandelier Tuff was formed during the Valles Caldera forming eruption at 1.2 million years ago. The now eroded and exposed orange-tan, light-colored Bandelier tuff from these events creates the stunning mesas of the Pajarito Plateau. Valles Caldera is the type locality for a resurgent dome caldera, the formation of, first developed by C. S. Ross, R. L. Smith, R. A. Bailey during field work at Valles in the 1960's. After the initial caldera forming eruption at Valles, the Redondo Peak resurgent dome was uplifted beginning around 1 million years ago. Eruption of moat rhyolitic lava domes occurred from 1.04 million years ago to 0.13 million years ago along a structural ring fracture zone.
The El Cajete Pumice, Battleship Rock Ignimbrite, the Banco Bonito obsidian flow were emplaced during the youn
Tectonic uplift is the portion of the total geologic uplift of the mean Earth surface, not attributable to an isostatic response to unloading. While isostatic response is important, an increase in the mean elevation of a region can only occur in response to tectonic processes of crustal thickening, changes in the density distribution of the crust and underlying mantle, flexural support due to the bending of rigid lithosphere. One should take into consideration the effects of denudation. Within the scope of this topic, uplift relates to denudation in that denudation brings buried rocks closer to the surface; this process can redistribute large loads from an elevated region to a topographically lower area as well – thus promoting an isostatic response in the region of denudation. The timing and rate of denudation can be estimated by geologists using pressure-temperature studies. Crustal thickening has an upward component of motion and occurs when continental crust is thrust onto continental crust.
Nappes from each plate collide and begin to stack one on top of the other. The preserved inverted metamorphic gradient indicates that nappes were stacked on top of each other so that hot rocks did not have time to equilibrate before being thrust on top of cool rocks; the process of nappe stacking can only continue for so long, as gravity will disallow further vertical growth. Although the raised surfaces of mountain ranges result from crustal thickening, there are other forces at play that are responsible for the tectonic activity. All tectonic processes are driven by gravitational force. A good example of this would be the large-scale circulation of the Earth's mantle. Lateral density variations near the surface drive plate motion; the dynamics of mountain ranges are governed by differences in the gravitational potential energy of entire columns of the lithosphere. If a change in surface height represents an isostatically compensated change in crustal thickness, the rate of change of potential energy per unit surface area is proportional to the rate of increase of average surface height.
The highest rates of working against gravity are required. Lithosphere on the oceanward side of an oceanic trench at a subduction zone will curve upwards due to the elastic properties of the Earth's crust. Orogenic uplift is the result of tectonic-plate collisions and results in mountain ranges or a more modest uplift over a large region; the most extreme form of orogenic uplift is a continental-continental crustal collision. In this process, two continents are sutured together and large mountain ranges are produced; the collision of the Indian and Eurasian plates is a good example of the extent to which orogenic uplift can reach. Heavy thrust faulting and folding are responsible for the suturing together of the two plates; the collision of the Indian and Eurasian plates not only produced the Himalaya but is responsible for crustal thickening north into Siberia. The Pamir Mountains, Tian Shan, Hindu Kush, other mountain belts are all examples of mountain ranges formed in response to the collision of the Indian with the Eurasian plate.
Deformation of continental lithosphere can take place in several possible modes. The Ozark Plateau is a broad uplifted area which resulted from the Permian Ouachita Orogeny to the south in the states of Arkansas and Texas. Another related uplift is the Llano Uplift in Texas, a geographical location named after its uplift features; the Colorado Plateau which includes the Grand Canyon is the result of broad tectonic uplift followed by river erosion. The removal of mass from a region will be isostatically compensated by crustal rebound. If we take into consideration typical crustal and mantle densities, erosion of an average 100 meters of rock across a broad, uniform surface will cause the crust to isostatically rebound about 85 meters and will cause only a 15-meter loss of mean surface elevation. An example of isostatic uplift would be post-glacial rebound following the melting of continental glaciers and ice sheets; the Hudson Bay region of Canada, the Great Lakes of Canada and the United States, Fennoscandia are undergoing gradual rebound as a result of the melting of ice sheets 10,000 years ago.
Crustal thickening, which for example is occurring in the Himalaya due to the continental collision between the Indian and the Eurasian plates, can lead to surface uplift. Therefore, in most convergent settings isostatic uplift plays a small role and high peak formation can be more attributed to tectonic processes. Direct measures of the elevation change of the land surface can only be used to estimate erosion or bedrock uplift rates when other controls are known. In a few cases, tectonic uplift can be seen in the cases of coral islands; this is evidenced by the presence of various oceanic islands composed of coral, which otherwise appear to be high islands (i.e. islands
Brazil the Federative Republic of Brazil, is the largest country in both South America and Latin America. At 8.5 million square kilometers and with over 208 million people, Brazil is the world's fifth-largest country by area and the fifth most populous. Its capital is Brasília, its most populated city is São Paulo; the federation is composed of the union of the 26 states, the Federal District, the 5,570 municipalities. It is the largest country to have Portuguese as an official language and the only one in the Americas. Bounded by the Atlantic Ocean on the east, Brazil has a coastline of 7,491 kilometers, it borders all other South American countries except Ecuador and Chile and covers 47.3% of the continent's land area. Its Amazon River basin includes a vast tropical forest, home to diverse wildlife, a variety of ecological systems, extensive natural resources spanning numerous protected habitats; this unique environmental heritage makes Brazil one of 17 megadiverse countries, is the subject of significant global interest and debate regarding deforestation and environmental protection.
Brazil was inhabited by numerous tribal nations prior to the landing in 1500 of explorer Pedro Álvares Cabral, who claimed the area for the Portuguese Empire. Brazil remained a Portuguese colony until 1808, when the capital of the empire was transferred from Lisbon to Rio de Janeiro. In 1815, the colony was elevated to the rank of kingdom upon the formation of the United Kingdom of Portugal and the Algarves. Independence was achieved in 1822 with the creation of the Empire of Brazil, a unitary state governed under a constitutional monarchy and a parliamentary system; the ratification of the first constitution in 1824 led to the formation of a bicameral legislature, now called the National Congress. The country became a presidential republic in 1889 following a military coup d'état. An authoritarian military junta came to power in 1964 and ruled until 1985, after which civilian governance resumed. Brazil's current constitution, formulated in 1988, defines it as a democratic federal republic. Due to its rich culture and history, the country ranks thirteenth in the world by number of UNESCO World Heritage Sites.
Brazil is considered an advanced emerging economy. It has the ninth largest GDP in the world by nominal, eight and PPP measures, it is one of the world's major breadbaskets, being the largest producer of coffee for the last 150 years. It is classified as an upper-middle income economy by the World Bank and a newly industrialized country, with the largest share of global wealth in Latin America. Brazil is a regional power and sometimes considered a great or a middle power in international affairs. On account of its international recognition and influence, the country is subsequently classified as an emerging power and a potential superpower by several analysts. Brazil is a founding member of the United Nations, the G20, BRICS, Union of South American Nations, Organization of American States, Organization of Ibero-American States and the Community of Portuguese Language Countries, it is that the word "Brazil" comes from the Portuguese word for brazilwood, a tree that once grew plentifully along the Brazilian coast.
In Portuguese, brazilwood is called pau-brasil, with the word brasil given the etymology "red like an ember", formed from brasa and the suffix -il. As brazilwood produces a deep red dye, it was valued by the European textile industry and was the earliest commercially exploited product from Brazil. Throughout the 16th century, massive amounts of brazilwood were harvested by indigenous peoples along the Brazilian coast, who sold the timber to European traders in return for assorted European consumer goods; the official Portuguese name of the land, in original Portuguese records, was the "Land of the Holy Cross", but European sailors and merchants called it the "Land of Brazil" because of the brazilwood trade. The popular appellation eclipsed and supplanted the official Portuguese name; some early sailors called it the "Land of Parrots". In the Guarani language, an official language of Paraguay, Brazil is called "Pindorama"; this was the name the indigenous population gave to the region, meaning "land of the palm trees".
Some of the earliest human remains found in the Americas, Luzia Woman, were found in the area of Pedro Leopoldo, Minas Gerais and provide evidence of human habitation going back at least 11,000 years. The earliest pottery found in the Western Hemisphere was excavated in the Amazon basin of Brazil and radiocarbon dated to 8,000 years ago; the pottery was found near Santarém and provides evidence that the tropical forest region supported a complex prehistoric culture. The Marajoara culture flourished on Marajó in the Amazon delta from 800 CE to 1400 CE, developing sophisticated pottery, social stratification, large populations, mound building, complex social formations such as chiefdoms. Around the time of the Portuguese arrival, the territory of current day Brazil had an estimated indigenous population of 7 million people semi-nomadic who subsisted on hunting, fishing and migrant agriculture; the indigenous population of Brazil comprised several large indigenous ethnic groups. The Tupí people were subdivided into the Tupiniquins and Tupinambás, there were many subdivisions of the other gro