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71-463: Manacapuru River is a river of Amazonas state in north-western Brazil . It flows into the Amazon River ( Solimões section) at the city of Manacapuru , about 80 km (50 mi) upstream (west) from Manaus . Parts of the river are very broad, appearing as elongated lakes, with the uppermost known as Lago Grande de Manacapuru ("Large Manacapuru Lake") and the lowermost, near where it merges into

142-470: A thin section using a method like the Gazzi-Dickinson Method . This yields the relative percentages of quartz, feldspar, and lithic grains and the amount of clay matrix. The composition of a sandstone can provide important information on the genesis of the sediments when used with a triangular Q uartz, F eldspar, L ithic fragment ( QFL diagrams ). However, geologist have not been able to agree on

213-562: A fishing and hunter-gatherer lifestyle. Because of Christopher Columbus' misunderstanding of the continent at which he had arrived, the native population were and are denominated "índios" by the Portuguese. Approximately two thousand Indian tribes lived in the region in the sixteenth century, perhaps amounting to some millions of people, but phenomena such as disease and assimilation to Brazilian culture caused their numbers to fall to approximately three hundred thousand, and two hundred tribes, by

284-564: A possession marker at the upper Japurá River in 1639. Soon after that the Portuguese bandeirante António Raposo Tavares , whose bandeira , leaving the captaincy of São Vicente travelling overland, reached the Andes, and following the Amazon River, returned to Belém, visiting a total of about 12,000 kilometres (7,500 mi), between 1648 and 1651. Tropical jungle is hostile and impenetrable as well as European settlements were exclusively along

355-478: A sandstone goes through as the degree of kinetic processing of the sediments increases. Dott's (1964) sandstone classification scheme is one of many such schemes used by geologists for classifying sandstones. Dott's scheme is a modification of Gilbert's classification of silicate sandstones, and it incorporates R.L. Folk's dual textural and compositional maturity concepts into one classification system. The philosophy behind combining Gilbert's and R. L. Folk's schemes

426-459: A set of boundaries separating regions of the QFL triangle. Visual aids are diagrams that allow geologists to interpret different characteristics of a sandstone. For example, a QFL chart can be marked with a provenance model that shows the likely tectonic origin of sandstones with various compositions of framework grains. Likewise, the stage of textural maturity chart illustrates the different stages that

497-445: A twofold classification: Cement is what binds the siliciclastic framework grains together. Cement is a secondary mineral that forms after deposition and during burial of the sandstone. These cementing materials may be either silicate minerals or non-silicate minerals, such as calcite. Sandstone that becomes depleted of its cement binder through weathering gradually becomes friable and unstable. This process can be somewhat reversed by

568-487: Is Manaus , a modern city of 2.1 million inhabitants in the middle of the jungle on the Amazon River, 1,500 km upstream from the Atlantic Ocean . Nearly half the state's population lives in the city; the other large cities, Parintins , Manacapuru , Itacoatiara , Tefé , and Coari are also along the Amazon River in the eastern half of the state. The name was originally given to the Amazon River that runs through

639-498: Is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks . Most sandstone is composed of quartz or feldspar , because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand , sandstone may be imparted any color by impurities within

710-837: Is a distinction that can be recognized in the field . In turn, the distinction between an orthoquartzite and a metaquartzite is the onset of recrystallization of existing grains. The dividing line may be placed at the point where strained quartz grains begin to be replaced by new, unstrained, small quartz grains, producing a mortar texture that can be identified in thin sections under a polarizing microscope. With increasing grade of metamorphism, further recrystallization produces foam texture , characterized by polygonal grains meeting at triple junctions, and then porphyroblastic texture , characterized by coarse, irregular grains, including some larger grains ( porphyroblasts .) Sandstone has been used since prehistoric times for construction, decorative art works and tools. It has been widely employed around

781-579: Is a populated place today, San Pablo, now the municipality of São Paulo de Olivença . Starting about 1580, without effective occupation, English, Dutch, French (and even some Irish) searching for so-called Drogas do Sertão (spices of the backlands ) had established some outposts upstream of the mouth of the Amazon. From at least the time of the Tordesillas Treaty in 1494 until the Treaty of Madrid in 1750,

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852-523: Is likely formed during eogenesis. Deeper burial is accompanied by mesogenesis , during which most of the compaction and lithification takes place. Compaction takes place as the sand comes under increasing pressure from overlying sediments. Sediment grains move into more compact arrangements, ductile grains (such as mica grains) are deformed, and pore space is reduced. In addition to this physical compaction, chemical compaction may take place via pressure solution . Points of contact between grains are under

923-410: Is one of the oldest in the Amazon, originating in a Mercedarian Indian mission founded in 1663. By the early 18th century, they were destroyed by the Portuguese, depopulated by smallpox, or their indigenous residents taken away as slaves by Portuguese Bandeirantes. A few were taken over by Portuguese Carmelites. The destruction of the missions was the end of Spanish claims in western Amazonia. Only one

994-431: Is redeposited in the unstrained pore spaces. Mechanical compaction takes place primarily at depths less than 1,000 meters (3,300 ft). Chemical compaction continues to depths of 2,000 meters (6,600 ft), and most cementation takes place at depths of 2,000–5,000 meters (6,600–16,400 ft). Unroofing of buried sandstone is accompanied by telogenesis , the third and final stage of diagenesis. As erosion reduces

1065-443: Is that it is better able to "portray the continuous nature of textural variation from mudstone to arenite and from stable to unstable grain composition". Dott's classification scheme is based on the mineralogy of framework grains, and on the type of matrix present in between the framework grains. In this specific classification scheme, Dott has set the boundary between arenite and wackes at 15% matrix. In addition, Dott also breaks up

1136-612: The Andes Mountains and explored the course of the river to the Atlantic Ocean. The indigenous people called this river the Conoris . The myth of women warriors on the river has spread in the accounts and books, without any popular scope, still making those regions to receive names of warriors of Greek mythology, the Amazons — among them the largest river in the region that became known as

1207-569: The Javari and the Carmelite aldeia of São Pedro; the other at the western mouth of the great river Japurá. This was the beginning of what came to be called the Jesuit–Carmelite War . Antidote to settlement was disease: fierce smallpox epidemics in 1661, 1695, 1724, and 1743/49 left the region nearly depopulated. A Carmelite Friar had notable success with the method of variolation in 1729, but

1278-623: The Portuguese Empire by the First Treaty of San Ildefonso . The State also includes territory from failed attempts at colonization by the European powers, such as England and the Dutch empire. The first Spanish expedition was by Francisco de Orellana in conjunction with Catholic priest Gaspar de Carvajal , who documented the expedition. He reported a conflict against indigenous women which led to

1349-459: The Province of Amazonas was officially created by Emperor Pedro II in 1850. From the mid-19th century, the territory began to receive migrants from the northeast seeking a better life. Attracted by the rubber boom, they settled in important Amazonian cities such as Manaus, Tabatinga, Parintins, Itacoatiara and Barcelos, the first capital of Amazonas. The state had an era of splendor in the 1890s, at

1420-701: The Spanish Empire 's Viceroyalty of Peru , a region called Spanish Guyana . It was settled by the Portuguese moving northwest from Brazil in the early 18th century and incorporated into the Portuguese empire after the Treaty of Madrid in 1750. It became a state under the First Brazilian Republic in 1889. Most of the state is tropical jungle ; cities are clustered along navigable waterways and are accessible only by boat or plane. The capital and largest city

1491-498: The percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs . Quartz-bearing sandstone can be changed into quartzite through metamorphism , usually related to tectonic compression within orogenic belts . Sandstones are clastic in origin (as opposed to either organic , like chalk and coal , or chemical , like gypsum and jasper ). The silicate sand grains from which they form are

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1562-600: The Amazon River flowed westward, perhaps as part of a proto-Congo (Zaïre) river system from the interior of present-day Africa when the continents were joined as part of western Gondwana . Fifteen million years ago, the Andes were formed by the collision of the South American Plate with the Nazca Plate (eastern Pacific oceanic) plate. The rise of the Andes and the linkage of the Brazilian and Guyana bedrock shields, blocked

1633-702: The Amazon River. Early publications, as was the style of the day, called the river after its European explorer, the Orellana . Also in the 16th century, there were the expeditions of conquistadores Pedro de Ursúa and Lope de Aguirre in search of the legendary El Dorado , the Lost City of Gold (1559–1561) Spanish Jesuit missions were the first settlements upstream on the Amazon. As many as 30 missions were founded in Amazon territory, seven in Brazil, between 1638 and 1727. The municipality of Silves on an island of Lake Saracá

1704-457: The Amazon, as Lago Manacapuru ("Lake Manacapuru"). 3°15′00″S 60°41′30″W  /  3.25000°S 60.69167°W  / -3.25000; -60.69167 This article related to a river in the Brazilian state of Amazonas is a stub . You can help Misplaced Pages by expanding it . Amazonas (Brazilian state) Amazonas is named after the Amazon River , and was formerly part of

1775-526: The Amazonas State, being the center of important artistic and cultural events. Bloomed so trade in luxury products and superfluous, with men and women from all over the world parading its streets and avenues, at purchase of the so-called "black gold" , as was dubbed the natural rubber, to resell big profits in the main capitals of Europe and in the United States from 1910, difficult times began, due to

1846-523: The Brazilian Amazon) was an economic development project implemented by Act number 3 173 of 3 June 1957, that reframed, enlarged and established tax incentives for deployment of an industrial, commercial and agricultural pole in a physical area of 10 000 km , with headquarters in the city of Manaus. Despite the adoption in 1957, that project has only been in fact deployed, by Decree-Law number 288 of 28 February 1967. Sandstone Sandstone

1917-959: The Jesuits, Carmelites, Capuchines and Franciscans: the Jesuits restricted their activities to the south bank of the Amazon upstream to the mouth of the Madeira; the north shore of the Amazon as far as the Trombetas fell to the Franciscans, to the mouth of the Rio Negro to the Mercedarians, and the Negro itself and the Solimoes to the Carmelites. The Portuguese Carmelites got a later start than the Spanish Jesuits, but their impact

1988-455: The Negro was that known as Santo Elias dos Tarumas (originally aldeia of Nossa Senhora da Conceição, and later called Airão), dating from 1692. the capital Manaus, was founded in 1669 as the Fort of São José do Rio Negro (later called Lugar da Barra do Rio Negro or "place on the shore of Rio Negro") on the confluence of the Rio Negro and Solimões Rivers. The Royal Charter of 1693 divided Amazonia among

2059-603: The Spanish and Portuguese possessions, the Viceroyalty of Peru (and successor states) and Grão-Pará region of Brazil, was set between 1781 and 1791 by negotiation. In 1821, Grão-Pará and Rio Negro provinces became the unified Grão-Pará . The following year, Brazil proclaimed its independence and Grão-Pará became the Province of Pará of state of Brazil. When Emperor Pedro I declared independence from Portugal, in 1822, he had to fight also

2130-511: The Upper Amazonas, under Pará. 1850 Province of Amazonas split from Pará 1889 State of Amazonas Capital 1755 village of São José do Javari; it became the vila Maryua 1758, Maryua is elevated to a town and called Barcelos 1788–1799, capital moved to Barra do Rio Negro; 1799–1808 The capital was again in Barcelos 1808 Barra do Rio Negro the capital, renamed Manaus in 1832 At one time

2201-491: The application of tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ) which will deposit amorphous silicon dioxide between the sand grains. The reaction is as follows. Pore space includes the open spaces within a rock or a soil. The pore space in a rock has a direct relationship to the porosity and permeability of the rock. The porosity and permeability are directly influenced by the way the sand grains are packed together. Sandstones are typically classified by point-counting

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2272-430: The area of the confluence of the Rio Negro and Amazon Rivers, in upper Amazonia. While the Treaty of Madrid in 1750 implicitly recognized the principle of uti possiditis , it did not actually specify the northern borders of the country. At that time, the border of contention between Spanish and Portuguese domains was in the upper Solimões, at the junction of the Rio Negro. In the upper Salomoes, Spanish missionary influence

2343-627: The autonomy of the Amazonas region as a separate province of Pará. The rebellion was suppressed, but the Amazons were able to send a representative to the Imperial Court, Friar José dos Santos Inocentes , who got up the creation of the District of the Upper Amazon. During Cabanagem in 1835–40, the Amazon remained loyal to the imperial government and not joined the revolt. As a sort of reward for loyalty,

2414-468: The common minerals most resistant to weathering processes at the Earth's surface, as seen in the Goldich dissolution series . Framework grains can be classified into several different categories based on their mineral composition: Matrix is very fine material, which is present within interstitial pore space between the framework grains. The nature of the matrix within the interstitial pore space results in

2485-613: The current name of the river, and then to the current name of the region and the state (Amazonas in English: Amazons ). The second Spanish expedition was by Pedro de Ursúa , intending to prove the previous expedition, but resulted in the Spanish Kingdom dropping the attempt to colonize the region. After the unification of the Iberian kingdoms, Portugal launched an expedition on the river [but in reverse from Francisco de Orellana, at

2556-456: The depositional environment, older sand is buried by younger sediments, and it undergoes diagenesis . This mostly consists of compaction and lithification of the sand. Early stages of diagenesis, described as eogenesis , take place at shallow depths (a few tens of meters) and are characterized by bioturbation and mineralogical changes in the sands, with only slight compaction. The red hematite that gives red bed sandstones their color

2627-407: The depth of burial, renewed exposure to meteoric water produces additional changes to the sandstone, such as dissolution of some of the cement to produce secondary porosity . Framework grains are sand-sized (0.0625-to-2-millimeter (0.00246 to 0.07874 in) diameter) detrital fragments that make up the bulk of a sandstone. Most framework grains are composed of quartz or feldspar , which are

2698-446: The different types of framework grains that can be present in a sandstone into three major categories: quartz, feldspar, and lithic grains. When sandstone is subjected to the great heat and pressure associated with regional metamorphism , the individual quartz grains recrystallize, along with the former cementing material, to form the metamorphic rock called quartzite . Most or all of the original texture and sedimentary structures of

2769-532: The emergence of Colombia , Ecuador , Venezuela and Panama . Brazil signed the Treaty Vásquez Cobo–Martins (1908) (with those countries) finally entitling those possessions in the north to Brazil. One region is marked by the geodesic line Apóporis-Tabatinga; and the other is the municipal area of São Gabriel da Cachoeira , on the Brazil-Colombia border . By the Treaty of Tordesillas (1494),

2840-460: The end of the twentieth century. Certain uncontacted tribes still exist in the region. In the colonial time, the territory which today belongs to the State of Amazonas, was a combination of treaties, expeditions, evangelism and military occupations. Scarce but recorded claims and indigenous uprisings in the region, were initially made by the Spanish Empire through the Treaty of Tordesillas and after

2911-557: The frontier of the northernmost captaincy of Maranhão with the expulsion of the French from São Luis in 1615, and the founding of Belém at the mouth of the Amazon in 1616. Exploration and colonization thence followed the waterway upstream. There are accounts of Portuguese Carmelite missionaries active in the Solimões area, upstream of the Rio Negro, as early as the 1620s, but permanent settlements weren't established for another 80 years, so

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2982-433: The greatest strain, and the strained mineral is more soluble than the rest of the grain. As a result, the contact points are dissolved away, allowing the grains to come into closer contact. Lithification follows closely on compaction, as increased temperatures at depth hasten deposition of cement that binds the grains together. Pressure solution contributes to cementing, as the mineral dissolved from strained contact points

3053-442: The hardness of individual grains, uniformity of grain size and friability of their structure, some types of sandstone are excellent materials from which to make grindstones , for sharpening blades and other implements. Non-friable sandstone can be used to make grindstones for grinding grain, e.g., gritstone . A type of pure quartz sandstone, orthoquartzite, with more of 90–95 percent of quartz, has been proposed for nomination to

3124-463: The ice ages ended, the forest was again joined, and the species that were once one, had diverged significantly enough to be designated as separate species, adding to the tremendous diversity of the region. About 6,000 years ago, sea levels rose about 130 meters, once again causing the river to be inundated like a long, giant freshwater lake. The pre-Columbian Amazonas was inhabited by seminomadic peoples whose livelihood mixed occasional agriculture with

3195-498: The island of Aibi near the mouth of Lake Arauató , followed by São Gabriel , founded in 1668 as by Franciscan Friar Teodózio [or Teodósio] da Veiga and Captain Pedro da Costa Favela on the Rio Negro, near the mouth of the Rio Aruím . In 1761, a fort was built on the location, and the settlement became the town of São Gabriel da Cachoeira . The first missionary aldea of the Portuguese in

3266-483: The minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the American Southwest . Rock formations composed of sandstone usually allow

3337-635: The mouth of the river to the site of the present-day city of Quito , capital of Ecuador ], with the intention of attaching Spanish lands (comprising the current territory of the Brazilian Amazon ) to the Portuguese Kingdom . After the dissolution of the Iberian Union , Portuguese and Spanish possessions in the region were undefined, resulting in internal conflicts in the region between Portugal and Spain . The Portuguese Crown later asserted

3408-493: The much lower temperatures and pressures associated with diagenesis of sedimentary rock, but diagenesis has cemented the rock so thoroughly that microscopic examination is necessary to distinguish it from metamorphic quartzite. The term orthoquartzite is used to distinguish such sedimentary rock from metaquartzite produced by metamorphism. By extension, the term orthoquartzite has occasionally been more generally applied to any quartz-cemented quartz arenite . Orthoquartzite (in

3479-464: The narrow sense) is often 99% SiO 2 with only very minor amounts of iron oxide and trace resistant minerals such as zircon , rutile and magnetite . Although few fossils are normally present, the original texture and sedimentary structures are preserved. The typical distinction between a true orthoquartzite and an ordinary quartz sandstone is that an orthoquartzite is so highly cemented that it will fracture across grains, not around them. This

3550-450: The peak of the rubber boom. However, the economic gains were largely the result of great human suffering: untold thousands of enslaved Amerindian seringueiros (rubber tappers) died through disease and overwork. Manaus, which already boasted as the capital administrative of the State, experienced a great population growth and the economic advancement, resulting mainly from exports of raw materials until then exclusively from Amazon Region. With

3621-437: The principle of uti possidetis , with respect to the region. This was the first assertion of the principle from Roman law of uti possidetis, ita possideatis , (Latin, "who has possession, has dominion"), analogous to English common law "Squatters rights" . Due account may have been taken of John Locke's labour theory of property. Conflicting issues arose between what was granted by law in the Treaty of Tordesillas (1494), and

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3692-638: The product of physical and chemical weathering of bedrock. Weathering and erosion are most rapid in areas of high relief, such as volcanic arcs , areas of continental rifting , and orogenic belts . Eroded sand is transported by rivers or by the wind from its source areas to depositional environments where tectonics has created accommodation space for sediments to accumulate. Forearc basins tend to accumulate sand rich in lithic grains and plagioclase . Intracontinental basins and grabens along continental margins are also common environments for deposition of sand. As sediments continue to accumulate in

3763-564: The provinces of Grão-Pará and Maranhão. In 1823, a ship commanded by British officer John Pascoe Grenfell arrived at the port of Belém , to combat rebels. Only in August 1824 did the new governor swear loyalty to the Brazilian Emperor. The Province of Pará , including the comarca of Rio Negro, the upper Amazon region, was incorporated into the Empire of Brazil in 1824. A revolt in 1832 demanded

3834-473: The records are nebulous. The first documented Portuguese foray into upper Amazonia was the expedition of Portuguese explorer and military officer Pedro Teixeira , who followed the great river from the Atlantic Ocean to Quito, Ecuador with 70 soldiers and 1,200 Indians in forty-seven great canoes (1637–1639). He returned by the same route, arriving back in Belem in 1639. According to the Portuguese, Pedro Teixeira placed

3905-643: The region of the upper Amazon was part of the Spanish Viceroyalty of Peru ( Viceroyalty of New Granada after 1717). Everything north of the Amazon (Solimões) and west of the Nhamundá River (Yamundá, in Spanish), an affluent of the left bank of the Amazon that forms the boundary of Amazonas with Pará, was known as Spanish Guyana. Portuguese expansion westward and northward of the Torsedillas Line began from

3976-467: The river and caused the Amazon to become a vast inland sea. Gradually this inland sea became a massive swampy, freshwater lake and the marine inhabitants adapted to life in freshwater. For example, over 20 species of stingray, most closely related to those found in the Pacific Ocean, can be found today in the fresh waters of the Amazon. About ten million years ago, waters worked through the sandstone to

4047-417: The sandstone are erased by the metamorphism. The grains are so tightly interlocked that when the rock is broken, it fractures through the grains to form an irregular or conchoidal fracture. Geologists had recognized by 1941 that some rocks show the macroscopic characteristics of quartzite, even though they have not undergone metamorphism at high pressure and temperature. These rocks have been subject only to

4118-720: The state by the Spaniard Francisco de Orellana in 1541. Claiming to have come across a warlike tribe of Natives, with whom he fought, he likened them to the Amazons of Greek mythology , giving them the same name of Río de las Amazonas . 1616 Captaincy of Maranhão begins westward expansion 1751 Maranhão reconstituted as state of Grão-Pará e Maranhão 1755 Captaincy of Rio Negro split off 1757 Captaincy of Rio Negro rejoined 1772 Grão-Pará e Rio Negro split from Grão-Pará e Maranhão. 1775 Captaincy of Grão-Pará of state of Brazil. 1821 Province of Pará 1822 Pará province of independent Brazil. 1832 Creation of Judicial District of

4189-648: The strong competition of natural rubber planted in rubber plantations the Asian continent, to European and American markets with superior advantages, which ultimately enact bankruptcy of Amazonian economy. By the late 19th century, the Brazilian rubber monopoly was slowly dying, as British and Dutch plantations in South-East Asia were producing cheaper, superior quality rubber, and by 1900 the Amazonas state had fallen into serious economic decline. Free trade zone of Manaus (also called Manaus Industrial Pole or Industrial Pole of

4260-512: The subsequent reality of colonial expansion: the Spanish, eastward from the Pacific coastal plains (though restrained by the Andes ), and the Portuguese, westward (aided by the waterways and lowlands of the mighty Amazon). The Treaty of Madrid (13 January 1750) – that determined the border between the Spanish possessions and southern Portuguese Brazil – had first enunciated the principle that new states, at

4331-475: The technique was not propagated. The Jenner cowpox vaccine was not introduced in Brazil until 1808. Variolation was prohibited in 1840, and vaccination was mandated in 1854. But epidemics got worse until finally petering out around the turn of the century. Within the project of occupying the Amazon hinterland, was formed the royal captaincy of São José do Rio Negro subordinate to Para, in Mar. 1755, with headquarters in

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4402-401: The time of their creation shall have dominion over the lands that were settled as colonies. It implicitly opened the door to claims by prior possession in the vast lands of the north. After the independence of Brazil in 1822, the current borders of the Amazonas State were still undefined – at that time being with Gran Colombia . The internal conflicts within that neighbour country resulted in

4473-476: The village of Mariuá, (now Barcelos). The boundary between the Portuguese and Spanish domination of the Amazon was eventually fixed at the Rio Javari (river that rises on the border between Amazonas state, Brazil, and Loreto department, Peru) by the Treaty of Madrid in 1750. By the mid-18th century, the effective boundary between the two empires, the Spanish Viceroyalty of Peru and Portuguese Brazil, had shifted to

4544-472: The waterways. Portuguese expansion generally was east to west, and from the main channel, the Solimões, north and south along the tributaries. The character of the settlements was of three kinds: defense and occupation ( fortes ), economic ( feitorias ), and evangelical ( missões ). The first permanent Portuguese settlements in the region were Itacoatiara 176 km east of Manaus, founded in 1655 by Portuguese Jesuit Padre António Vieira as Mission of Aroaquis on

4615-463: The wealth generated by the production and export of natural rubber ( Hevea brasiliensis ), the amazonian capital received large works such as the port of Manaus, the Amazonas Opera House , Palace of Justice, Reservoir of Mocó , the first network of electric energy and public transport services as trams. Vista as a reference, your headquarters became a symbol of prosperity and civilization for

4686-566: The west and the Amazon began to flow eastward. At this time the Amazon rainforest was born. During the Ice Age, sea levels dropped and the great Amazon lake rapidly drained and became a river. Three million years later, the ocean level receded enough to expose the Central American isthmus and allow mass migration of mammal species between the Americas. The Ice Ages caused tropical rainforest around

4757-710: The whole Amazon basin was in the area of the Spanish Crown. The mouth of a great river was explored by Spanish conquistador Vicente Yáñez Pinzón , who reached it in February 1500, with his cousin Diego de Lepe . He called the river Río Santa María de la Mar Dulce (River of Saint Mary of the Sweet Sea) on account of the large freshwater estuary extending into the sea at its mouth. In 1541, Spanish conquistadores Gonzalo Pizarro and Francisco de Orellana , from Quito , Ecuador, crossed

4828-612: The world in constructing temples, churches, homes and other buildings, and in civil engineering . Although its resistance to weathering varies, sandstone is easy to work. That makes it a common building and paving material, including in asphalt concrete . However, some types that have been used in the past, such as the Collyhurst sandstone used in North West England , have had poor long-term weather resistance, necessitating repair and replacement in older buildings. Because of

4899-476: The world to retreat. Although debated, it is believed that much of the Amazon reverted to savanna and montane forest . Savanna divided patches of rainforest into "islands" and separated existing species for periods long enough to allow genetic differentiation. A similar rainforest retreat took place in Africa, where Delta core samples suggest that even the mighty Congo watershed was void of rainforest at this time. When

4970-529: Was being displaced, and the Viceroy was indifferent to colonization, but Portuguese settlements were not yet established. Part of the northern boundary between Brazil and what was then British Guyana, was set by the Spanish Boundary-line Commission of Yturriaga and Solano (1757–1763). After two indecisive wars between Portuguese and Spanish colonial forces 1761–1763 and 1776–1777, the border between

5041-419: Was more durable. Between 1697 and 1757, they established eight missions on the Solimões and nine on the Rio Negro. In addition, there were a few Portuguese Jesuit missions in the Solimões. In 1731, Portuguese Jesuits received orders from the Governor Luiz de Vasconcellos Lobo to establish two aldeias above the mouth of the Rio Negro, one on the right bank of the Orellana Solimões , between the eastern mouth of

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