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Río de la Plata Craton

April 11, 2024

The Rio de la Plata Craton (RPC) is a medium-sized continental block found in Uruguay, eastern Argentina and southern Brazil. During its complex and protracted history it interacted with a series other blocks and is therefore considered important for the understanding of the amalgamation of West Gondwana. Two orogenic cycles have been identified in the RPC: a 2000 Ma-old western domain representing the old craton and a 700–500 Ma-old eastern domain assigned to the Brasiliano Cycle.[1] It is one of the five cratons (ancient nuclei) of the South American continent. The other four cratons are: Amazonia, São Francisco, Río Apa and Arequipa–Antofalla.

Atlantica at about 2.0 Ga. Archaean cratons in grey. Modern continents added for orientation.
Approximate location of Mesoproterozoic (older than 1.3 Ga) cratons in South America and Africa.

Geology edit

See also: Dyke swarms of Tandil and Azul
 
Shear zones and terranes in Uruguay after Gaucher et al. 2008, Fig. 1

Three shear zones divides the Precambrian basement of Uruguay and southern Brazil into four terranes.

Along the Uruguayan east coast (reaching into Brazil) is the Cuchilla Dionisio Terrane, an allochthonous African block juxtaposed to the RPC along the Sierra Ballena Shear Zone (SBSZ).[1]

West of Cuchilla Dionisio, the Nico Pérez Terrane is delimited by two longitudinal shear zones: the SBSZ and the Late Mesoporterozoic Sarandí del Yí Shear Zone (SYSZ). In the Nico Pérez Terrane Archean-Paleoproterozoic-aged metamorphic and granitoid rocks as well as Neoproterzoic sedimentary successions crop out.[1][2] The Neoproterzoic sedimentary successions probably deposited on an Atlantic-style continental shelf.[1] The terrane hosts a swarm of NEE-SSW oriented dykes that date to the Neoproterozoic.[3] It has however not been established to which degree Nico Pérez Terrane belongs to –or has affinity with– the Río de la Plata Craton.[2]

East of the SYSZ, the latitudinal Colonia Shear Zone (CSZ) separates the Palaeoproterozoic (2000±100 Ma) Piedra Alta Terrane to the north from the Tandilia Terrane to the south.[1] A period of extensional tectonics in the Late Paleoproterozoic coincided with the formation and intrusion of the Piedra Alta mafic dike swarm and the rapakivi granites of Illescas Batholith.[4] The 1790±5 Ma-old Late Palaeoproterozoic Piedra Alta mafic dike swarm was subsequently affected by the 8 km (5.0 mi)-wide Mesoproterozoic SYSZ and its eastern end bends along the dextral megashear zone.[1][5]

Tectonic evolution edit

Today, the Río de la Plata Craton crops out in southern Uruguay and parts of Buenos Aires Province, Argentina. Crystalline rocks of the Río de la Plata Craton are dated between 2200 and 1700 million years ago, such as rocks in Uruguay which are dated at 1790 ±5 Ma.[6] Dikes trending east-northeast in the same area are dated by argon-argon dating at 1727 ±10 Ma.[7] The craton has a size of about 20,000 square kilometres (7,700 sq mi).

West Gondwana was assembled along the Transbrasiliano lineament in the Mid-Cambrian as, on one side, Amazonia, Río Apa, and some minor blocks collided with, on the other side, São Francisco/Congo, Río de la Plata, and some minor blocks. South of this lineament, along the western margin of the Río de la Plata Craton, the 535-520 Ma-old Pampean orogeny is partly made of an exotic terrane that was accreted to Gondwana's proto-Pacific margin (i.e. before the Andes had formed.)[8]

The Adamastor Ocean, a "proto-Atlantic" ocean that opened with the break-up of the Rodinia supercontinent 780-750 Ma, separated the Río de la Plata Craton from the Congo Craton. The inversion of the Adamastor Ocean began 640 Ma with the development of a large back-arc basin along the western margin of the Kalahari Craton and the ocean closed when Río de la Plata collided with Kalahari about 545 Ma along the sinistral Sierra Ballena Shear Zone.[9] The São Francisco and Río de la Plata cratons amalgamated 630–620 Ma, closing the Adamastor Ocean on the South American side and forming the Mantiqueira Mountains around 600 Ma.[10]

References edit

  1. ^ a b c d e f Gaucher et al. 2008, Introduction, pp. 151–152
  2. ^ a b Sánchez Bettucci, Leda; Cordani, Umberto; Loureiro, Judith; Peel, Elena; Fort, Santiago; Sato, Kei (2021). "The Nico Pérez terrane (Uruguay) and its archean and paleoproterozoic inheritance". Andean Geology. 48 (3): 442–471. doi:10.5027/andgeoV48n3-3345. ISSN 0718-7092. Retrieved November 28, 2021.
  3. ^ Rivalanti, G.; Mazzucchelli, M.; Molesini, M.; Petrini, R.; Girardi, V.A.V.; Bossi, J.; Campal, N. (1995). "Petrology of late proterozoic mafic dikes in the Nico Perez region, central Uruguay". Mineralogy and Petrology. 55 (4): 239–263. Bibcode:1995MinPe..55..239R. doi:10.1007/BF01165120. S2CID 127280699.
  4. ^ Teixeira, Wilson; D'Agrella-Filho, Manoel S.; Hamilton, Mike A.; Ernst, Richard E.; Girardi, Vicente A.V.; Mazzucchelli, Maurizio; Bettencourt, Jorge S. (2013). "U–Pb (ID-TIMS) baddeleyite ages and paleomagnetism of 1.79 and 1.59 Ga tholeiitic dyke swarms, and position of the Rio de la Plata Craton within the Columbia supercontinent". Lithos. 174: 157–174. Bibcode:2013Litho.174..157T. doi:10.1016/j.lithos.2012.09.006.
  5. ^ Mazzucchelli, Maurizio; Rivalenti, Giorgio; Piccirillo, Enzo Michele; Vitorio Girardi, Vicente Antonio; Civetta, Lucia; Petrini, Riccardo (1995). "Petrology of the Proterozoic mafic dyke swarms of Uruguay and constraints on their mantle source composition". Precambrian Research. 74 (3): 177–194. Bibcode:1995PreR...74..177M. doi:10.1016/0301-9268(95)00014-v.
  6. ^ Halls et al. 2001
  7. ^ Teixeira et al. 1999
  8. ^ Rapela et al. 2007, Introduction, pp. 50–52
  9. ^ Rapela et al. 2007, 7.6 Tectonic Model, p. 76
  10. ^ Brito Neves, Campos Neto & Fuck 1999, Mantiqueira branched systems of orogens, pp. 161–162

Bibliography edit

  • Brito Neves, B. B. D.; Campos Neto, M. D. C.; Fuck, R. A. (1999). "From Rodinia to Western Gondwana: an approach to the Brasiliano-Pan African Cycle and orogenic collage". Episodes. 22 (3): 155–166. CiteSeerX 10.1.1.466.4214. doi:10.18814/epiiugs/1999/v22i3/002.
  • Gaucher, C.; Finney, S. C.; Poiré, D. G.; Valencia, V. A.; Grove, M.; Blanco, G.; Pamoukaghlián, K.; Peral, L. G. (2008). "Detrital zircon ages of Neoproterozoic sedimentary successions in Uruguay and Argentina: insights into the geological evolution of the Río de la Plata Craton". Precambrian Research. 167 (1): 150–170. Bibcode:2008PreR..167..150G. doi:10.1016/j.precamres.2008.07.006. hdl:11336/74329. Retrieved 5 January 2016.
  • Halls, H.C.; Campal, N.; Davis, D.W.; Bossi, J. (2001). "Magnetic studies and U-Pb geochronology of the Uruguayan dyke swarm, Río de la Plata craton, Uruguay: Paleomagnetic and economic implications" (pdf). Journal of South American Earth Sciences. 14 (4): 349–361. Bibcode:2001JSAES..14..349H. doi:10.1016/S0895-9811(01)00031-1. Retrieved 5 January 2016.
  • Rapela, C.W.; Pankhurst, R.J.; Casquet, C.; Fanning, C.M.; Baldo, E.G.; González-Casado, J.M.; Galindo, C.; Dahlquist, J. (2007). "The Río de la Plata craton and the assembly of SW Gondwana". Earth-Science Reviews. 83 (1–2): 49–82. Bibcode:2007ESRv...83...49R. doi:10.1016/j.earscirev.2007.03.004. hdl:1885/33417. S2CID 128539355. Retrieved 5 January 2016.
  • Teixeira, W.; Renne, P.R.; Bossi, J.; Campal, N.; D'Agrella Filho, M.S. (1999). "40Ar-39Ar and Rb-Sr geochronology of the Uruguayan dike swarm, Río de la Plata Craton and implications for Proterozoic intraplate activity in Western Gondwana". Precambrian Research. 93 (2–3): 153–180. Bibcode:1999PreR...93..153T. doi:10.1016/S0301-9268(98)00087-4.

April 11, 2024
río, plata, craton, plata, craton, medium, sized, continental, block, found, uruguay, eastern, argentina, southern, brazil, during, complex, protracted, history, interacted, with, series, other, blocks, therefore, considered, important, understanding, amalgama. The Rio de la Plata Craton RPC is a medium sized continental block found in Uruguay eastern Argentina and southern Brazil During its complex and protracted history it interacted with a series other blocks and is therefore considered important for the understanding of the amalgamation of West Gondwana Two orogenic cycles have been identified in the RPC a 2000 Ma old western domain representing the old craton and a 700 500 Ma old eastern domain assigned to the Brasiliano Cycle 1 It is one of the five cratons ancient nuclei of the South American continent The other four cratons are Amazonia Sao Francisco Rio Apa and Arequipa Antofalla Atlantica at about 2 0 Ga Archaean cratons in grey Modern continents added for orientation Approximate location of Mesoproterozoic older than 1 3 Ga cratons in South America and Africa Contents 1 Geology 2 Tectonic evolution 3 References 3 1 BibliographyGeology editSee also Dyke swarms of Tandil and Azul nbsp Shear zones and terranes in Uruguay after Gaucher et al 2008 Fig 1Three shear zones divides the Precambrian basement of Uruguay and southern Brazil into four terranes Along the Uruguayan east coast reaching into Brazil is the Cuchilla Dionisio Terrane an allochthonous African block juxtaposed to the RPC along the Sierra Ballena Shear Zone SBSZ 1 West of Cuchilla Dionisio the Nico Perez Terrane is delimited by two longitudinal shear zones the SBSZ and the Late Mesoporterozoic Sarandi del Yi Shear Zone SYSZ In the Nico Perez Terrane Archean Paleoproterozoic aged metamorphic and granitoid rocks as well as Neoproterzoic sedimentary successions crop out 1 2 The Neoproterzoic sedimentary successions probably deposited on an Atlantic style continental shelf 1 The terrane hosts a swarm of NEE SSW oriented dykes that date to the Neoproterozoic 3 It has however not been established to which degree Nico Perez Terrane belongs to or has affinity with the Rio de la Plata Craton 2 East of the SYSZ the latitudinal Colonia Shear Zone CSZ separates the Palaeoproterozoic 2000 100 Ma Piedra Alta Terrane to the north from the Tandilia Terrane to the south 1 A period of extensional tectonics in the Late Paleoproterozoic coincided with the formation and intrusion of the Piedra Alta mafic dike swarm and the rapakivi granites of Illescas Batholith 4 The 1790 5 Ma old Late Palaeoproterozoic Piedra Alta mafic dike swarm was subsequently affected by the 8 km 5 0 mi wide Mesoproterozoic SYSZ and its eastern end bends along the dextral megashear zone 1 5 Tectonic evolution editToday the Rio de la Plata Craton crops out in southern Uruguay and parts of Buenos Aires Province Argentina Crystalline rocks of the Rio de la Plata Craton are dated between 2200 and 1700 million years ago such as rocks in Uruguay which are dated at 1790 5 Ma 6 Dikes trending east northeast in the same area are dated by argon argon dating at 1727 10 Ma 7 The craton has a size of about 20 000 square kilometres 7 700 sq mi West Gondwana was assembled along the Transbrasiliano lineament in the Mid Cambrian as on one side Amazonia Rio Apa and some minor blocks collided with on the other side Sao Francisco Congo Rio de la Plata and some minor blocks South of this lineament along the western margin of the Rio de la Plata Craton the 535 520 Ma old Pampean orogeny is partly made of an exotic terrane that was accreted to Gondwana s proto Pacific margin i e before the Andes had formed 8 The Adamastor Ocean a proto Atlantic ocean that opened with the break up of the Rodinia supercontinent 780 750 Ma separated the Rio de la Plata Craton from the Congo Craton The inversion of the Adamastor Ocean began 640 Ma with the development of a large back arc basin along the western margin of the Kalahari Craton and the ocean closed when Rio de la Plata collided with Kalahari about 545 Ma along the sinistral Sierra Ballena Shear Zone 9 The Sao Francisco and Rio de la Plata cratons amalgamated 630 620 Ma closing the Adamastor Ocean on the South American side and forming the Mantiqueira Mountains around 600 Ma 10 References edit a b c d e f Gaucher et al 2008 Introduction pp 151 152 a b Sanchez Bettucci Leda Cordani Umberto Loureiro Judith Peel Elena Fort Santiago Sato Kei 2021 The Nico Perez terrane Uruguay and its archean and paleoproterozoic inheritance Andean Geology 48 3 442 471 doi 10 5027 andgeoV48n3 3345 ISSN 0718 7092 Retrieved November 28 2021 Rivalanti G Mazzucchelli M Molesini M Petrini R Girardi V A V Bossi J Campal N 1995 Petrology of late proterozoic mafic dikes in the Nico Perez region central Uruguay Mineralogy and Petrology 55 4 239 263 Bibcode 1995MinPe 55 239R doi 10 1007 BF01165120 S2CID 127280699 Teixeira Wilson D Agrella Filho Manoel S Hamilton Mike A Ernst Richard E Girardi Vicente A V Mazzucchelli Maurizio Bettencourt Jorge S 2013 U Pb ID TIMS baddeleyite ages and paleomagnetism of 1 79 and 1 59 Ga tholeiitic dyke swarms and position of the Rio de la Plata Craton within the Columbia supercontinent Lithos 174 157 174 Bibcode 2013Litho 174 157T doi 10 1016 j lithos 2012 09 006 Mazzucchelli Maurizio Rivalenti Giorgio Piccirillo Enzo Michele Vitorio Girardi Vicente Antonio Civetta Lucia Petrini Riccardo 1995 Petrology of the Proterozoic mafic dyke swarms of Uruguay and constraints on their mantle source composition Precambrian Research 74 3 177 194 Bibcode 1995PreR 74 177M doi 10 1016 0301 9268 95 00014 v Halls et al 2001 Teixeira et al 1999 Rapela et al 2007 Introduction pp 50 52 Rapela et al 2007 7 6 Tectonic Model p 76 Brito Neves Campos Neto amp Fuck 1999 Mantiqueira branched systems of orogens pp 161 162 Bibliography edit Brito Neves B B D Campos Neto M D C Fuck R A 1999 From Rodinia to Western Gondwana an approach to the Brasiliano Pan African Cycle and orogenic collage Episodes 22 3 155 166 CiteSeerX 10 1 1 466 4214 doi 10 18814 epiiugs 1999 v22i3 002 Gaucher C Finney S C Poire D G Valencia V A Grove M Blanco G Pamoukaghlian K Peral L G 2008 Detrital zircon ages of Neoproterozoic sedimentary successions in Uruguay and Argentina insights into the geological evolution of the Rio de la Plata Craton Precambrian Research 167 1 150 170 Bibcode 2008PreR 167 150G doi 10 1016 j precamres 2008 07 006 hdl 11336 74329 Retrieved 5 January 2016 Halls H C Campal N Davis D W Bossi J 2001 Magnetic studies and U Pb geochronology of the Uruguayan dyke swarm Rio de la Plata craton Uruguay Paleomagnetic and economic implications pdf Journal of South American Earth Sciences 14 4 349 361 Bibcode 2001JSAES 14 349H doi 10 1016 S0895 9811 01 00031 1 Retrieved 5 January 2016 Rapela C W Pankhurst R J Casquet C Fanning C M Baldo E G Gonzalez Casado J M Galindo C Dahlquist J 2007 The Rio de la Plata craton and the assembly of SW Gondwana Earth Science Reviews 83 1 2 49 82 Bibcode 2007ESRv 83 49R doi 10 1016 j earscirev 2007 03 004 hdl 1885 33417 S2CID 128539355 Retrieved 5 January 2016 Teixeira W Renne P R Bossi J Campal N D Agrella Filho M S 1999 40Ar 39Ar and Rb Sr geochronology of the Uruguayan dike swarm Rio de la Plata Craton and implications for Proterozoic intraplate activity in Western Gondwana Precambrian Research 93 2 3 153 180 Bibcode 1999PreR 93 153T doi 10 1016 S0301 9268 98 00087 4 Retrieved from https en wikipedia org w index php title Rio de la Plata Craton amp oldid 1170167118, wikipedia, wiki, book, books, library,

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