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114-544: The Omingonde Formation is correlated with a series of formations in northwestern Argentina and the Paraná Basin in southeastern Brazil, deposited in a larger basinal area, 120 million years before the break-up of Pangea . The formation has provided fossils of several therapsids , amphibians and ichnofossils and belongs to the Cynognathus Assemblage Zone . The Omingonde Formation preserves

228-793: A middle power in international affairs. A major non-NATO ally of the United States, Argentina is a developing country with the second-highest HDI (human development index) in Latin America after Chile . It maintains the second-largest economy in South America, and is a member of G-15 and G20 . Argentina is also a founding member of the United Nations , World Bank , World Trade Organization , Mercosur , Community of Latin American and Caribbean States and

342-669: A clandestine organization. José López Rega organized the Argentine Anticommunist Alliance (AAA) to fight against them and the People's Revolutionary Army (ERP). Perón died in July 1974 and was succeeded by his wife, who signed a secret decree empowering the military and the police to "annihilate" the left-wing subversion, stopping ERP's attempt to start a rural insurgence in Tucumán province. Isabel Perón

456-490: A climbing-ripple lamination. Furthermore, the mudstones contain thin interlayers of blocky calcrete and carbonate nodules with some rhizoliths . Massive pebbly mudstones are restricted to positions very proximal to the Waterberg-Omaruru Fault. They are characterised by a massive matrix-supported texture and a low structural and compositional maturity of both, matrix and clasts. The Upper Omingonde Formation

570-684: A critical role in the party, died of cancer in 1952. As the economy continued to tank, Perón started losing popular support, and came to be seen as a threat to the national process. The Navy took advantage of Perón's withering political power, and bombed the Plaza de Mayo in 1955. Perón survived the attack, but a few months later, during the Liberating Revolution coup, he was deposed and went into exile in Spain. The new head of State, Pedro Eugenio Aramburu , proscribed Peronism and banned

684-463: A final heart attack on Monday, 1 July 1974, and died at 13:15. He was 78 years old. After his death, Isabel Perón , his wife and vice president, succeeded him in office. During her presidency, a military junta, along with the Peronists' far-right fascist faction, once again became the de facto head of state . Isabel Perón served as President of Argentina from 1974 until 1976, when she was ousted by

798-551: A left-wing Peronist, who took office on 25 May 1973. A month later, in June, Perón returned from Spain. One of Cámpora's first presidential actions was to grant amnesty to members of organizations that had carried out political assassinations and terrorist attacks, and to those who had been tried and sentenced to prison by judges. Cámpora's months-long tenure in government was beset by political and social unrest. Over 600 social conflicts, strikes , and factory occupations took place within

912-402: A lower subzone characterized by Kestrosaurus , a middle subzone characterized by the "classic" zone fauna which was already well-established, and an upper zone with reduced diversity. This informal three-part subdivision scheme was later labelled with letters (as subzones A, B, and C from oldest to youngest) until it was formalized with robust index taxa and type sections in 2020. Subzone A

1026-684: A military coup d'état led by General Arturo Rawson toppled the democratically elected government of Ramón Castillo . Under pressure from the United States, later Argentina declared war on the Axis Powers (on 27 March 1945, roughly a month before the end of World War II in Europe ). During the Rawson dictatorship a relatively unknown military colonel named Juan Perón was named head of the Labour Department. Perón quickly managed to climb

1140-656: A mobile braided stream system due to the well developed trough cross-bedding and upward-fining character of poorly confined channel bodies, together with their sheet-like appearance and ubiquitous vertical and lateral amalgamation. In addition, significant vertical accretion is indicated by the preservation of overbank fines, that abundantly show pedogenic modification. The proximal deposits of the Erongo area show textural and grain size characteristics of debris flows that amalgamated to form fault-bounded alluvial fan aprons. These fans give evidence for persistent syn-sedimentary activity of

1254-778: A part of Antarctica . The earliest recorded human presence in modern-day Argentina dates back to the Paleolithic period. The Inca Empire expanded to the northwest of the country in Pre-Columbian times. The country has its roots in Spanish colonization of the region during the 16th century. Argentina rose as the successor state of the Viceroyalty of the Río de la Plata , a Spanish overseas viceroyalty founded in 1776. The declaration and fight for independence (1810–1818)

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1368-569: A proposal known as the Inca plan of 1816, which proposed that the United Provinces of the Río de la Plata (Present Argentina) should be a monarchy, led by a descendant of the Inca . Juan Bautista Túpac Amaru (half-brother of Túpac Amaru II ) was proposed as monarch. Some examples of those who supported this proposal were Manuel Belgrano , José de San Martín and Martín Miguel de Güemes . The Congress of Tucumán finally decided to reject

1482-613: A second term . With the economy beginning to decline in 1995, and with increasing unemployment and recession, the UCR, led by Fernando de la Rúa , returned to the presidency in the 1999 elections . De la Rúa left Menem's economic plan in effect despite the worsening crisis, which led to growing social discontent. Massive capital flight from the country was responded to with a freezing of bank accounts , generating further turmoil. The December 2001 riots forced him to resign. Congress appointed Eduardo Duhalde as acting president, who revoked

1596-467: A single month. Even though far-left terrorist organisations had suspended their armed struggle, their joining with the participatory democracy process was interpreted as a direct threat by the Peronist right-wing faction. Amid a state of political, social, and economic upheaval, Cámpora and Vice President Vicente Solano Lima resigned in July 1973, calling for new elections, but this time with Perón as

1710-414: A system of social assistance for the most vulnerable sectors of society. The economy began to decline in 1950 due in part to government expenditures and the protectionist economic policies. He also engaged in a campaign of political suppression. Anyone who was perceived to be a political dissident or potential rival was subject to threats, physical violence and harassment. The Argentine intelligentsia ,

1824-499: A transitional stage to the facies of the Lower Etjo Formation. The syn-sedimentary tectonic control on Omingonde deposition is recorded by both thickening of strata towards the Waterberg-Omaruru Fault and by the pronounced shift of the adjacent depocenter, the latter suggesting left-lateral oblique slip movement. The formation belongs to the Cynognathus Assemblage Zone as identified by Keyser in 1973; and preserves

1938-637: Is a federal state subdivided into twenty-three provinces , and one autonomous city , which is the federal capital and largest city of the nation, Buenos Aires . The provinces and the capital have their own constitutions, but exist under a federal system . Argentina claims sovereignty over the Falkland Islands , South Georgia and the South Sandwich Islands , the Southern Patagonian Ice Field , and

2052-772: Is a tetrapod biozone utilized in the Karoo Basin of South Africa . It is equivalent to the Burgersdorp Formation , the youngest lithostratigraphic formation in the Beaufort Group , which is part of the fossiliferous and geologically important Karoo Supergroup . The Cynognathus Assemblage Zone is the youngest of the eight biozones found in the Beaufort Group, and is considered to be late Early Triassic ( Olenekian ) to early Middle Triassic ( Anisian ) in age (around 247 Ma). The name of

2166-616: Is best developed in the Mt. Waterberg area, but no occurrences have been found in the Goboboseb-Otjongundu region. The succession begins with a laterally amalgamated channel facies alternating with a sandy mudstone facies. In the lower units, the channel bodies are 80 to 150 metres (260 to 490 ft) wide and the degree of lateral amalgamation is similar to the Middle Omingonde Formation, but vertical stacking

2280-822: Is correlated with a wide variety of geological formations. Similar cynodont and dicynodont species are known from the Lower Omingonde Formation of Namibia , the Lower Ntawere Formation of Zambia , and the lower Lifua Member of the Tanzanian Manda Beds . These correlations can be extended beyond Africa, as far as the Fremouw Formation of Antarctica , Donguz Formation (" Eryosuchus fauna") of Russia, and Lower Ermaying Formation of China. Cynognathus and Diademodon fossils have even been found in

2394-495: Is far more common than trirachodontids. However, by the contact with Subzone C, trirachodontids had become the dominant taxa. Cynognathus is the common denominator, with its fossils found throughout Subzones A – C, confirming its place as the index taxon of the biozone as a whole. The large dicynodont Kannemeyeria simocephalus appears in Subzone B alongside other anomodonts, and therocephalian species can be found throughout

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2508-540: Is less pronounced and decreases systematically upwards. In the upper part of the formation, channels are isolated and only a few meters wide. Up-section, the maturity of channel fills successively increases until well rounded medium to coarse grained sandstones dominate. The architecture remains cyclic with the channel facies alternating with laminated fine grained sandstones and bioturbated mudstones. The Omingonde Formation comprises chiefly braided fluvial deposits, which record semi-arid climatic conditions prevailing until

2622-514: Is the most common temnospondyl in this subzone. The Trirachodon-Kannemeyeria Subzone also has the highest diversity of fish, plants, and archosauromorph reptiles in the entire Assemblage Zone. The erythrosuchid Erythrosuchus africanus is a common component of the fauna, living alongside its smaller relative Euparkeria capensis and several species of early rhynchosaurs ( Howesia browni , Eohyosaurus wolvaardti , Mesosuchus browni ). The Cricodon - Ufudocyclops Subzone (Subzone C)

2736-639: Is the oldest subzone in the Cynognathus Assemblage Zone. Its base is defined by the first appearance of Cynognathus crateronotus , as well as the trirachodontid cynodont Langbergia modisei and the erythrosuchid archosauriform Garjainia madiba . The temnospondyl amphibians Kestrosaurus and Parotosuchus haughtoni are also common and distinctive fossils of the Langbergia-Garjainia Subzone. Dicynodonts are absent, unlike every other zone and subzone in

2850-426: Is the youngest subzone, and has the most restricted exposures and fossil content. Its base is defined by the first appearance of the trirachodontid Cricodon metabolus and the dicynodont Ufudocyclops mukanelai , the only species which are common in this subzone. Cynognathus and Diademodon still persist, though they are far more rare than in the previous subzone. Other species with utility for correlation include

2964-651: Is widespread in the Otjiwarongo, Grootfontein and Omaruru Districts. Main outcrops are south of the Waterberg thrust near Mount Etjo, Omatakos and north of the Waterberg Plateau . The Omingonde Formation splits naturally into four units, each comprising several upward-fining cycles reflecting distinct architectural characteristics. The lower two units coincide with the Lower and Middle Omingonde Formation,

3078-632: The Cordobazo and the Rosariazo . The terrorist guerrilla organization Montoneros kidnapped and executed Aramburu. The newly chosen head of government, Alejandro Agustín Lanusse , seeking to ease the growing political pressure, allowed Héctor José Cámpora to become the Peronist candidate instead of Perón. Cámpora won the March 1973 election , issued pardons for condemned guerrilla members, and then secured Perón's return from his exile in Spain. On

3192-506: The Beaufort Group . The Cynognathus Assemblage Zone contains argillaceous mudstone successions varying from maroon to reddish, blueish-green, and greyish-green in colour. The mudstones are interbedded with lenticular and feldspathic sandstones which appear greenish-grey when fresh and brownish-yellow when eroded out. Clay -rich pebble conglomerates are also observed in some areas. Complete, articulated fossils are frequently found encased in calcareous nodules within

3306-624: The Bombing of Plaza de Mayo in 1955. The Trelew massacre of 1972, the actions of the Argentine Anticommunist Alliance commencing in 1973, and Isabel Perón 's "annihilation decrees" against left-wing guerrillas during Operativo Independencia (Operation Independence) in 1975, are also possible events signaling the beginning of the Dirty War. Onganía shut down Congress, banned all political parties, and dismantled student and worker unions. In 1969, popular discontent led to two massive protests:

3420-738: The Centralists and the Federalists —a move that would define Argentina's first decades of independence. The Assembly of the Year XIII appointed Gervasio Antonio de Posadas as Argentina's first Supreme Director . On 9 July 1816, the Congress of Tucumán formalized the Declaration of Independence , which is now celebrated as Independence Day, a national holiday. One year later General Martín Miguel de Güemes stopped royalists on

3534-709: The Charrúa , Minuane and Guaraní in the northeast, with slash and burn semisedentary existence; the advanced Diaguita sedentary trading culture in the northwest, which was conquered by the Inca Empire around 1480; the Toconoté and Hênîa and Kâmîare in the country's centre, and the Huarpe in the centre-west, a culture that raised llama cattle and was strongly influenced by the Incas. Europeans first arrived in

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3648-571: The Free State that border Lesotho . The Langbergia - Garjainia Subzone (Subzone A) is most well-exposed and fossiliferous in northeast Free State, between Senekal and Bethlehem . At the stratotype near Bethlehem, it reaches around 50 m in thickness. Exposures of this subzone rapidly decrease to the east, disappearing around Bergville . Although the subzone thickens further south (to up to 100 m) towards Aliwal North, fossils diminish in abundance. Sediments of Subzone A are likely present in

3762-655: The Karoo Basin of southern Namibia and the Eastern , Northern and Western Cape , South Africa , the formation is time-equivalent with the Burgersdorp and Elliot Formation . In Antarctica , the formation correlates with the Fremouw Formation . Argentina Argentina , officially the Argentine Republic , is a country in the southern half of South America . Argentina covers an area of 2,780,400 km (1,073,500 sq mi), making it

3876-578: The Laborioust candidate. The Labour Party (later renamed Justicialist Party ), the most powerful and influential party in Argentine history, came into power with the rise of Juan Perón to the presidency in 1946. He nationalized strategic industries and services, improved wages and working conditions, paid the full external debt and claimed he achieved nearly full employment . He pushed Congress to enact women's suffrage in 1947, and developed

3990-626: The Langbergia-Garjainia Subzone is correlated with the Yarenskian Gorizont (" Parotosuchus fauna") of Russia . The " Parotosuchus fauna", exemplified by the Petropavlovskya Svita (a local lithological unit), is assigned to the late Olenekian Stage (latest Early Triassic, about 249-247 Ma) based on correlation with nearby marine fauna. The classic faunal assemblage of the Trirachodon - Kannemeyeria Subzone

4104-508: The Macri Government introduced neoliberal austerity measures intended to tackle inflation and overblown public deficits. Under Macri's administration, economic recovery remained elusive with GDP shrinking 3.4%, inflation totaling 240%, billions of US dollars issued in sovereign debt, and mass poverty increasing by the end of his term. He ran for re-election in 2019 but lost by nearly eight percentage points to Alberto Fernández ,

4218-839: The Nonesian Land Vertebrate Faunachron , part of a heavily-debated global system of Triassic tetrapod biostratigraphy. The Cricodon-Ufudocyclops Subzone may be correlated with the upper parts of the Omingonde, Ntawere, and Manda Formations in Africa. Paracyclotosaurus is also known from the Yerrapalli Formation and Upper Denwa Formation of India , while Shansiodon is found in the Upper Ermaying Formation (" Sinokannemeyeria fauna") of China. Shansiodon defines

4332-590: The Organization of Ibero-American States . The description of the region by the word Argentina has been found on a Venetian map in 1536. In English, the name Argentina comes from the Spanish language ; however, the naming itself is not Spanish, but Italian . Argentina ( masculine argentino ) means in Italian '(made) of silver, silver coloured', derived from the Latin argentum for silver. In Italian,

4446-601: The Río Seco de la Quebrada Formation of Mendoza Province , Argentina . These formations are often considered early Anisian in age (earliest Middle Triassic, about 247 Ma). However, there is some debate over their age; one ash bed below the Rio Seco de la Quebrada Formation was radiometrically dated to around 236 Ma (early Carnian), much younger than previously suggested purely based on tetrapod biostratigraphy. The classic Cynognathus Assemblage Zone has been equated with

4560-581: The Southern Cone . The Dirty War involved state terrorism in Argentina and elsewhere in the Southern Cone against political dissidents, with military and security forces employing urban and rural violence against left-wing guerrillas, political dissidents, and anyone believed to be associated with socialism or somehow contrary to the neoliberal economic policies of the regime. Victims of

4674-582: The Spanish Empire , and " United Provinces of the Río de la Plata " after independence. The 1826 constitution included the first use of the name "Argentine Republic" in legal documents. The name "Argentine Confederation" was also commonly used and was formalized in the Argentine Constitution of 1853 . In 1860 a presidential decree settled the country's name as "Argentine Republic", and that year's constitutional amendment ruled all

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4788-670: The absolutist monarchy that ruled the country. As in the rest of Spanish America, the overthrow of Ferdinand VII during the Peninsular War created great concern. Beginning a process from which Argentina was to emerge as successor state to the Viceroyalty, the 1810 May Revolution replaced the viceroy Baltasar Hidalgo de Cisneros with the First Junta , a new government in Buenos Aires made up from locals. In

4902-464: The mudstone layers while complete skulls are mainly found in the sandstone . The mudstones were likely deposited in low-energy, meandering fluvial environments alongside sand-rich river channels . The environment during time of deposition was semi-arid , but with seasonal rain and flooding due to the presence of crevasse splays in the mudstone layers. A lack of well developed channel sandstones provides evidence for more lacustrine areas in

5016-520: The neo-Keynesian economic policies laid by Duhalde, Kirchner ended the economic crisis attaining significant fiscal and trade surpluses, and rapid GDP growth. Under his administration, Argentina restructured its defaulted debt with an unprecedented discount of about 70% on most bonds, paid off debts with the International Monetary Fund , purged the military of officers with dubious human rights records, nullified and voided

5130-601: The second-largest country in South America after Brazil , the fourth-largest country in the Americas , and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina

5244-463: The 1916 election . He enacted social and economic reforms and extended assistance to small farms and businesses. Argentina stayed neutral during World War I . The second administration of Yrigoyen faced an economic crisis, precipitated by the Great Depression . In 1930, Yrigoyen was ousted from power by the military led by José Félix Uriburu . Although Argentina remained among the fifteen richest countries until mid-century, this coup d'état marks

5358-414: The Beaufort Group. The Trirachodon-Kannemeyeria Subzone (Subzone B) corresponds to traditional conceptions of the Cynognathus Assemblage Zone. Alongside abundant fossils of Cynognathus crateronotus , the base of Subzone B sees the first appearance of fellow cynodonts Diademodon tetragonus and Trirachodon berryi . Dicynodonts reappear with Kannemeyeria simocephalus , while Xenotosuchus africanus

5472-551: The Eastern Cape, though a lack of sufficient fossil material prevents it from being distinguished from younger strata. The Trirachodon - Kannemeyeria Subzone (Subzone B) is the thickest and historically the most well-studied portion of the Assemblage Zone. It is primarily exposed in the Eastern Cape south of Lesotho. Subzone B reaches up to 500 m thick at the stratotype between Queenstown and Lady Frere, thinning northwards until it disappears east of Thaba 'Nchu . The Cricodon - Ufudocyclops Subzone (Subzone C) has limited exposures in

5586-415: The Falkland Islands . The United Kingdom dispatched a task force to regain possession. Argentina surrendered on 14 June and its forces were taken home. Street riots in Buenos Aires followed the humiliating defeat and the military leadership stood down. Reynaldo Bignone replaced Galtieri and began to organize the transition to democratic governance. Raúl Alfonsín won the 1983 elections campaigning for

5700-431: The Full Stop and Due Obedience laws, ruled them as unconstitutional, and resumed legal prosecution of the Junta's crimes. He did not run for reelection, promoting instead the candidacy of his wife, senator Cristina Fernández de Kirchner , who was elected in 2007 and reelected in 2011 . Fernández de Kirchner's administration established positive foreign relations with countries such as Venezuela, Iran, and Cuba, while at

5814-439: The Inca plan, creating instead a republican, centralist state. The 1820 Battle of Cepeda , fought between the Centralists and the Federalists, resulted in the end of the Supreme Director rule . In 1826 Buenos Aires enacted another centralist constitution , with Bernardino Rivadavia being appointed as the first president of the country. However, the interior provinces soon rose against him, forced his resignation and discarded

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5928-508: The Justicialist Party candidate. President Alberto Fernández and Vice President Cristina Fernández de Kirchner took office in December 2019, just months before the COVID-19 pandemic hit Argentina and among accusations of corruption , bribery and misuse of public funds during Nestor and Cristina Fernández de Kirchner's presidencies . On 14 November 2021, the center-left coalition of Argentina's ruling Peronist party, Frente de Todos (Front for Everyone), lost its majority in Congress, for

6042-490: The Justicialist Party nominee. Perón won the election with his wife Isabel Perón as vice president. Perón's third term was marked by escalating conflict between left and right-wing factions within the Peronist party, as well as the return of armed terror guerrilla groups such as the Guevarist ERP , leftist Peronist Montoneros , and the state-backed far-right Triple A . After a series of heart attacks and signs of pneumonia in 1974, Perón's health deteriorated quickly. He suffered

6156-409: The Krantzberg Formation in the western, northern and eastern Erongo area, and interfingers with the Lions Head Formation towards the southeastern Erongo Region. North of the Ameib Line, which is part of the Waterberg-Omaruru Fault zone, no rocks of Karoo age are preserved until the Otjongundu Basin, which hosts a 350 metres (1,150 ft) thick conglomeratic red-bed sequence that probably correlates with

6270-763: The Omingonde Formation. The formation comprises red and white colored clastics including conglomerates , sandstones and siltstones . Many units are channelized and show paleosol development. Three major facies are developed in the lower unit, including channelized, trough cross-bedded conglomerates, followed by sandy mudstones, which are interbedded with more massive, pebbly mudstones. The conglomerates are matrix-supported and grade vertically and laterally into sandstones. Their clasts derived dominantly from metasedimentary and granitic rocks. The channels are usually well confined and amalgamation occurs rarely. The sandy mudstones are reddish in colour, they contain lenticular interbeds of fine grained sandstones. They are characterised by

6384-472: The Peronist Carlos Menem won the 1989 election . Soon after, riots forced Alfonsín to an early resignation . Menem embraced and enacted neoliberal policies: a fixed exchange rate , business deregulation , privatizations , and the dismantling of protectionist barriers normalized the economy in the short term. He pardoned the officers who had been sentenced during Alfonsín's government. The 1994 Constitutional Amendment allowed Menem to be elected for

6498-439: The United States government during the Johnson , Nixon , Ford , Carter , and Reagan administrations. The exact chronology of the repression is still debated, yet the roots of the long political war may have started in 1969 when trade unionists were targeted for assassination by Peronist and Marxist paramilitaries. Individual cases of state-sponsored terrorism against Peronism and the left can be traced back even further to

6612-562: The United States'—led to a near-reinvention of Argentine society and economy that by 1908 had placed the country as the seventh wealthiest developed nation in the world. Driven by this immigration wave and decreasing mortality, the Argentine population grew fivefold and the economy 15-fold: from 1870 to 1910, Argentina's wheat exports went from 100,000 to 2,500,000 t (110,000 to 2,760,000 short tons) per year, while frozen beef exports increased from 25,000 to 365,000 t (28,000 to 402,000 short tons) per year, placing Argentina as one of

6726-458: The Upper Omingonde Formation. The latter marks a temporary shift to a wetter climate until semi-arid conditions re-established with the succeeding Etjo Formation. The degree of channel amalgamation and palaeosol development corresponds with sediment discharge rates: More confined meandering channels and extensive palaeosol developments are associated with lower discharge rates rather than amalgamated braided channel systems. The channel geometries and

6840-399: The Waterberg Fault system. The Upper Omingonde Formation reflects a progressive change from a braided river system to a more meandering river system with decreasing discharge rates. Temporarily wetter climates are indicated by bioturbated mudstones, that formed in seasonal lakes. Although a hiatus to the overlying Etjo Formation is proposed, the facies of the Upper Omingonde Formation represents

6954-488: The adjective or the proper noun is often used in an autonomous way as a substantive and replaces it and it is said l'Argentina . The name Argentina was probably first given by the Venetian and Genoese navigators, such as Giovanni Caboto . In Spanish and Portuguese, the words for 'silver' are respectively plata and prata and '(made) of silver' is plateado and prateado , although argento for 'silver' and argentado for 'covered in silver' exist in Spanish. Argentina

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7068-398: The allegiance of escaped Filipinos in San Blas who defected from the Spanish to join the Argentine navy, due to common Argentine and Philippine grievances against Spanish colonization. Jose de San Martin's brother, Juan Fermín de San Martín , was already in the Philippines and drumming up revolutionary fervor prior to this. At a later date, the Argentine sign of Inca origin, the Sun of May

7182-401: The area now known as Argentina are dated from the Paleolithic period, with further traces in the Mesolithic and Neolithic . Until the period of European colonization, Argentina was relatively sparsely populated by a wide number of diverse cultures with different social organizations, which can be divided into three main groups. The first group are basic hunters and food gatherers without

7296-484: The biozone refers to Cynognathus crateronotus , a large and carnivorous cynodont therapsid which occurs throughout the entire biozone. The first fossils to be found in the Beaufort Group rocks that encompass the current eight biozones were discovered by Andrew Geddes Bain in 1856. However, it was not until 1892 that it was observed that the geological strata of the Beaufort Group could be differentiated based on their fossil taxa . The initial undertaking

7410-566: The biozone. Apart from synapsids , the biozone is rich in other fossil fauna , including procolophonid parareptiles and archosauromorph reptiles. Plant fossils such as Dicroidium , Dadoxylon , and Schizoneura have been uncovered from limited areas corresponding to Subzones B - C. Aquatic life is well represented: numerous species of temnospondyl amphibian , fishes, rare occurrences of molluscs , and ichnofossils of arthropod trackways and vertebrate burrows have been discovered. The Langbergia - Garjainia Subzone (Subzone A)

7524-400: The border, and the appropriation of the indigenous territories. The first conquest consisted of a series of military incursions into the Pampa and Patagonian territories dominated by the indigenous peoples, distributing them among the members of the Sociedad Rural Argentina , financiers of the expeditions. The conquest of Chaco lasted up to the end of the century, since its full ownership of

7638-444: The constitution. Centralists and Federalists resumed the civil war; the latter prevailed and formed the Argentine Confederation in 1831, led by Juan Manuel de Rosas . During his regime he faced a French blockade (1838–1840), the War of the Confederation (1836–1839), and an Anglo-French blockade (1845–1850), but remained undefeated and prevented further loss of national territory. His trade restriction policies, however, angered

7752-437: The country was slow to meet its original goals of industrialization: after the steep development of capital-intensive local industries in the 1920s, a significant part of the manufacturing sector remained labour-intensive in the 1930s. Between 1878 and 1884, the so-called Conquest of the Desert occurred, with the purpose of tripling the Argentine territory by means of the constant confrontations between natives and Criollos in

7866-407: The day Perón returned to Argentina, the clash between Peronist internal factions— right-wing union leaders and left-wing youth from the Montoneros—resulted in the Ezeiza Massacre . Overwhelmed by political violence, Cámpora resigned and Perón won the following September 1973 election with his third wife Isabel as vice-president. He expelled Montoneros from the party and they became once again

7980-402: The development of pottery , such as the Selk'nam and Yaghan in the extreme south. The second group are advanced hunters and food gatherers which include the Puelche , Querandí and Serranos in the centre-east; and the Tehuelche in the south—all of them conquered by the Mapuche spreading from Chile —and the Kom and Wichi in the north. The last group are farmers with pottery, such as

8094-404: The first ballotage in Argentina's history, beating Front for Victory candidate Daniel Scioli and becoming president-elect. Macri was the first democratically elected non- peronist president since 1916 that managed to complete his term in office without being overthrown. He took office on 10 December 2015 and inherited an economy with a high inflation rate and in a poor shape. In April 2016,

8208-652: The first clashes of the Independence War the Junta crushed a royalist counter-revolution in Córdoba , but failed to overcome those of the Banda Oriental , Upper Peru and Paraguay , which later became independent states. The French-Argentine Hippolyte Bouchard then brought his fleet to wage war against Spain overseas and attacked Spanish California , Spanish Peru and Spanish Philippines . He secured

8322-492: The first time in almost 40 years, in midterm legislative elections . The election victory of the center-right coalition, Juntos por el Cambio (Together for Change) limited President Alberto Fernandez's power during his final two years in office. Losing control of the Senate made it difficult for him to make key appointments, including to the judiciary. It also forced him to negotiate with the opposition every initiative he sends to

8436-424: The fixed exchange rate established by Menem, causing many working- and middle-class Argentines to lose a significant portion of their savings. By late 2002, the economic crisis began to recede, but the assassination of two piqueteros by the police caused political unrest, prompting Duhalde to move elections forward. Néstor Kirchner was elected as the new president . On 26 May 2003, he was sworn in. Boosting

8550-724: The formation: The formation is correlated with the lower part of the Santa Maria Formation of the Paraná Basin in Rio Grande do Sul , Brazil . The Chañares Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina is also time-equivalent with the Omingonde Formation, and similar fauna assemblages as the Omingonde Formation have been reported from the Río Seco de la Quebrada Formation of Argentina. In

8664-498: The government after elected labour movement officials were forcefully replaced by Peronist puppets from the Peronist Party . Reyes was soon arrested on charges of terrorism, though the allegations were never substantiated. Reyes, who was never formally charged, was tortured in prison for five years and only released after the regime's downfall in 1955. Perón managed to get re-elected in 1951 . His wife Eva Perón , who played

8778-511: The interior provinces and in 1852 Justo José de Urquiza , another powerful caudillo , beat him out of power . As the new president of the Confederation, Urquiza enacted the liberal and federal 1853 Constitution. Buenos Aires seceded but was forced back into the Confederation after being defeated in the 1859 Battle of Cepeda . Overpowering Urquiza in the 1861 Battle of Pavón , Bartolomé Mitre secured Buenos Aires' predominance and

8892-610: The left-wing. By the end of 1976, the Montoneros had lost nearly 2,000 members and by 1977, the ERP was completely subdued. Nevertheless, the severely weakened Montoneros launched a counterattack in 1979, which was quickly put down, effectively ending the guerrilla threat and securing the junta's position in power. In March 1982, an Argentine force took control of the British territory of South Georgia and, on 2 April, Argentina invaded

9006-496: The legislature. In April 2023, President Alberto Fernandez announced that he will not seek re-election in the next presidential election . The 19 November 2023 election run-off vote ended in a win for libertarian outsider Javier Milei with close to 56% of the vote against 44% of the ruling coalition candidate Sergio Massa . On 10 December 2023, Javier Milei was sworn in as the new president of Argentina. Cynognathus Assemblage Zone The Cynognathus Assemblage Zone

9120-604: The low degree of amalgamation in the Lower Omingonde Formation indicate an overall meandering river system. Sandy mudstones were generated during crevasse splays and associated flood stages. Intervals of non-deposition are indicated by immature paleosols, which are represented by scarce rhizoliths and blocky calcretes. In proximal positions to the Waterberg-Omaruru Fault pebbly mudstone units reveal mud flow deposits related to an enhanced fault generated relief. The Middle Omingonde Formation has been interpreted as

9234-418: The middle-class, university students, and professors were seen as particularly troublesome. Perón fired over 2,000 university professors and faculty members from all major public education institutions. Perón tried to bring most trade and labour unions under his thumb, regularly resorting to violence when needed. For instance, the meat-packers union leader, Cipriano Reyes , organized strikes in protest against

9348-408: The military. Her short presidency was marked by the collapse of Argentine political and social systems, leading to a constitutional crisis that paved the way for a decade of instability, left-wing terrorist guerrilla attacks, and state-sponsored terrorism. The "Dirty War" (Spanish: Guerra Sucia ) was part of Operation Condor , which included the participation of other right-wing dictatorships in

9462-481: The more northerly occurring outcrops of the biozone. The thickest outcrops of the Cynognathus Assemblage Zone, reaching approximately 600 metres (2,000 ft), occur between Queenstown and Lady Frere in the Eastern Cape . Outcrops then thin out to between 200 and 100 metres (660 and 330 ft) around Aliwal North , Burgersdorp , Steynsburg , and Rouxville . Thin outcrops are also found in areas in

9576-672: The most diverse fauna of Middle Triassic cynodonts in the world. The Omingonde Formation is named after a water well in Mount Etjo , Namibia. The formation is a lithological unit with an approximate maximum thickness of 600 metres (2,000 ft), deposited in the Waterberg Basin where it overlies the Damara basement , and is unconformably overlain by the Early Jurassic Etjo Sandstone . The formation

9690-585: The most diverse fauna of Middle Triassic cynodonts in the world; the formation is a biostratigraphic link among Middle Triassic faunas from South Africa, Tanzania ( Manda Formation ), Zambia, Argentina, Brazil, and Antarctica. The cynodonts of the Triassic era are important markers to correlate terrestrial formations. Trirachodon fossils have also been found in the Driekoppen Formation of South Africa. The following fossils have been reported from

9804-417: The names since 1810 as legally valid. In English , the country was traditionally called "the Argentine", mimicking the typical Spanish usage la Argentina and perhaps resulting from a mistaken shortening of the fuller name 'Argentine Republic'. 'The Argentine' fell out of fashion during the mid-to-late 20th century, and now the country is referred to as "Argentina". The earliest traces of human life in

9918-507: The national economic system only took place when the mere extraction of wood and tannin was replaced by the production of cotton . The Argentine government considered indigenous people as inferior beings, without the same rights as Criollos and Europeans. In 1912, President Roque Sáenz Peña enacted universal and secret male suffrage , which allowed Hipólito Yrigoyen , leader of the Radical Civic Union (or UCR), to win

10032-555: The north, and General José de San Martín . He joined Bernardo O'Higgins and they led a combined army across the Andes and secured the independence of Chile; then it was sent by O'Higgins orders to the Spanish stronghold of Lima and proclaimed the independence of Peru . In 1819 Buenos Aires enacted a centralist constitution that was soon abrogated by federalists. Some of the most important figures of Argentine independence made

10146-448: The party from any future elections. Arturo Frondizi from the UCR won the 1958 general election . He encouraged investment to achieve energetic and industrial self-sufficiency, reversed a chronic trade deficit and lifted the ban on Peronism; yet his efforts to stay on good terms with both the Peronists and the military earned him the rejection of both and a new coup forced him out. Amidst

10260-417: The political ladder, being named Minister of Defence by 1944. Being perceived as a political threat by rivals in the military and the conservative camp, he was forced to resign in 1945, and was arrested days later. He was finally released under mounting pressure from both his base and several allied unions. He would later become president after a landslide victory over the UCR in the 1946 general election as

10374-414: The political turmoil, Senate leader José María Guido reacted swiftly and applied anti- power vacuum legislation, ascending to the presidency himself; elections were repealed and Peronism was prohibited once again. Arturo Illia was elected in 1963 and led an increase in prosperity across the board; however he was overthrown in 1966 by another military coup d'état led by General Juan Carlos Onganía in

10488-535: The presidency, before being overthrown in 1976 . The following military junta , which was supported by the United States , persecuted and murdered thousands of political critics, activists, and leftists in the Dirty War , a period of state terrorism and civil unrest that lasted until the election of Raúl Alfonsín as president in 1983 . Argentina is a regional power , and retains its historic status as

10602-622: The prosecution of those responsible for human rights violations during the Proceso : the Trial of the Juntas and other martial courts sentenced all the coup's leaders but, under military pressure, he also enacted the Full Stop and Due Obedience laws, which halted prosecutions further down the chain of command . The worsening economic crisis and hyperinflation reduced his popular support and

10716-557: The region with the 1502 voyage of Amerigo Vespucci . The Spanish navigators Juan Díaz de Solís and Sebastian Cabot visited the territory that is now Argentina in 1516 and 1526, respectively. In 1536 Pedro de Mendoza founded the small settlement of Buenos Aires , which was abandoned in 1541. Further colonization efforts came from Paraguay —establishing the Governorate of the Río de la Plata — Peru and Chile. Francisco de Aguirre founded Santiago del Estero in 1553. Londres

10830-620: The same time relations with the United States and the United Kingdom became increasingly strained. By 2015, the Argentine GDP grew by 2.7% and real incomes had risen over 50% since the post-Menem era. Despite these economic gains and increased renewable energy production and subsidies, the overall economy had been sluggish since 2011. On 22 November 2015, after a tie in the first round of presidential elections on 25 October , center-right coalition candidate Mauricio Macri won

10944-512: The self-proclaimed Argentine Revolution , creating a new military government that sought to rule indefinitely. Following several years of military rule, Alejandro Agustín Lanusse was appointed president by the military junta in 1971. Under increasing political pressure for the return of democracy, Lanusse called for elections in 1973. Perón was banned from running but the Peronist party was allowed to participate. The presidential elections were won by Perón's surrogate candidate, Hector Cámpora ,

11058-504: The silver and gold mines in Bolivia and Peru, and as such it became part of the Viceroyalty of Peru until the creation of the Viceroyalty of the Río de la Plata in 1776 with Buenos Aires as its capital. Buenos Aires repelled two ill-fated British invasions in 1806 and 1807. The ideas of the Age of Enlightenment and the example of the first Atlantic Revolutions generated criticism of

11172-434: The start of the steady economic and social decline that pushed the country back into underdevelopment. Uriburu ruled for two years; then Agustín Pedro Justo was elected in a fraudulent election , and signed a controversial treaty with the United Kingdom . Argentina stayed neutral during World War II , a decision that had full British support but was rejected by the United States after the attack on Pearl Harbor . In 1943

11286-559: The temnospondyl Paracyclotosaurus morganorum and the dicynodont Shansiodon sp., which co-occur in the lower part of the subzone. Based on tentative biostratigraphic correlations, the Cynognathus Assemblage Zone is considered to have been emplaced from approximately 249 to 244 Ma, in the later part of the Early Triassic and early part of the Middle Triassic. Based on the presence of Garjainia and Parotosuchus ,

11400-601: The time and were left largely unchanged for several decades. James Kitching retained the name of the Cynognathus z one in his revision of the biozones in the 1970s and 1980s. In 1995, he formalized the biozone under the name " Cynognathus Assemblage Zone". In the mid-1990s, new discoveries of additional outcrops presented the possibility that the Cynognathus Assemblage Zone could be subdivided further. A 1995 paper split it into three subzones:

11514-632: The upper two units make up the Upper Omingonde Formation. Thicknesses and architectural style of the units vary laterally and are influenced by syn-sedimentary tectonic activity of the Waterberg-Omaruru Lineament. The full range of facies is best developed in the Mt. Waterberg area, whereas farther west in the Erongo Region more proximal facies are favored. This proximal facies association has been termed

11628-594: The vicinity of Molteno and Sterkstroom in the Eastern Cape. It reaches up to 150 m at its stratotype in Sterkstroom. The Cynognathus Assemblage Zone holds a rich diversity of fossil species , of which it is most renowned for its cynodont fossils. Cynognathids , diademodontids , and trirachodontids are found throughout the Assemblage Zone. In Subzone B, the diademodontid Diademodon

11742-450: The violence in Argentina alone included an estimated 15,000 to 30,000 left-wing activists and militants, including trade unionists, students, journalists, Marxists , Peronist guerrillas , and alleged sympathizers. Most of the victims were casualties of state terrorism . The opposing guerrillas' victims numbered nearly 500–540 military and police officials and up to 230 civilians. Argentina received technical support and military aid from

11856-510: The world's top five exporters. Its railway mileage rose from 503 to 31,104 km (313 to 19,327 mi). Fostered by a new public, compulsory, free and secular education system, literacy quickly increased from 22% to 65%, a level higher than most Latin American nations would reach even fifty years later. Furthermore, real GDP grew so fast that despite the huge immigration influx, per capita income between 1862 and 1920 went from 67% of developed country levels to 100%: In 1865, Argentina

11970-591: Was adopted as a symbol by the Filipinos in the Philippine Revolution against Spain. He also secured the diplomatic recognition of Argentina from King Kamehameha I of the Kingdom of Hawaii . Historian Pacho O'Donnell affirms that Hawaii was the first state that recognized Argentina's independence. He was finally arrested in 1819 by Chilean patriots. Revolutionaries split into two antagonist groups:

12084-473: Was already one of the top 25 nations by per capita income. By 1908, it had surpassed Denmark, Canada and the Netherlands to reach 7th place—behind Switzerland, New Zealand, Australia, the United States, the United Kingdom and Belgium. Argentina's per capita income was 70% higher than Italy's, 90% higher than Spain's, 180% higher than Japan's and 400% higher than Brazil 's. Despite these unique achievements,

12198-486: Was done by Harry Govier Seeley who subdivided the Beaufort Group into three biozones , which he named (from oldest to youngest): Under Seeley's system, the "highly specialized theriodonts" zone corresponds to the modern Cynognathus Assemblage Zone. Seeley's proposed biozones were subdivided further by Robert Broom between 1906 and 1909. Broom proposed the following biozones (from oldest to youngest): These biozone divisions were approved by paleontologists of

12312-404: Was elected as the first president of the reunified country. He was followed by Domingo Faustino Sarmiento and Nicolás Avellaneda ; these three presidencies set up the basis of the modern Argentine State. Starting with Julio Argentino Roca in 1880, ten consecutive federal governments emphasized liberal economic policies . The massive wave of European immigration they promoted—second only to

12426-485: Was first associated with the silver mountains legend , widespread among the first European explorers of the La Plata Basin . The first written use of the name in Spanish can be traced to La Argentina , a 1602 poem by Martín del Barco Centenera describing the region. Although "Argentina" was already in common usage by the 18th century, the country was formally named " Viceroyalty of the Río de la Plata " by

12540-431: Was followed by an extended civil war that lasted until 1861, culminating in the country's reorganization as a federation . The country thereafter enjoyed relative peace and stability, with several waves of European immigration , mainly Italians and Spaniards , influencing its culture and demography . Following the death of President Juan Perón in 1974, his widow and vice president, Isabel Perón , ascended to

12654-772: Was formalized as the Langbergia - Garjainia Subzone, subzone B as the Trirachodon - Kannemeyeria Subzone, and subzone C as the Cricodon - Ufudocyclops Subzone. From the late 1970s onwards, some authors argued that Cynognathus was less common than previously considered, so they instead renamed the biozone to the Kannemeyeria Assemblage Zone or Kannemeyeria- Diademodon Assemblage Zone. However, later work found that Kannemeyeria fossils were absent from Subzone A, and while Diademodon

12768-483: Was found throughout the biozone it had been usurped as a dominant taxon by larger trirachodontids by Subzone C. This meant that these species were not ideal index taxa for the biozone. As Cynognathus fossils are found consistently throughout, the current name for the biozone was retained. The Cynognathus Assemblage Zone correlates with the Burgersdorp Formation in the upper Tarkastad Subgroup of

12882-413: Was founded in 1558; Mendoza , in 1561; San Juan , in 1562; San Miguel de Tucumán , in 1565. Juan de Garay founded Santa Fe in 1573 and the same year Jerónimo Luis de Cabrera set up Córdoba . Garay went further south to re-found Buenos Aires in 1580. San Luis was established in 1596. The Spanish Empire subordinated the economic potential of the Argentine territory to the immediate wealth of

12996-599: Was ousted one year later by a junta of the combined armed forces, led by army general Jorge Rafael Videla . They initiated the National Reorganization Process , often shortened to Proceso . The Proceso shut down Congress, removed the judges on the Supreme Court, banned political parties and unions, and resorted to employing the forced disappearance of suspected guerrilla members including individuals suspected of being associated with

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