The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: A Paleoproterozoic through Cretaceous saga of a reworked continental margin

The Cabo Frio Tectonic Domain is composed of a Paleoproterozoic basement tectonically interleaved with Neoproterozoic supracrustal rocks (Buzios-Palmital successions). It is in contact with the Neoproterozoic-Cambrian Ribeira Orogen along the SE Brazilian coast. The basement was part of at least three continental margins: (a) 1.97 Ga; (b) 0.59 - 0.53 Ga; (c) 0.14 Ga to today. It consists of continental magmatic arc rocks of 1.99 to 1.94 Ga. Zircon cores show a 2.5 - 2.6 Ga inheritance from the ancient margin of the Congo Craton. During the Ediacaran, this domain was thinned and intruded by tholeiitic mafic dykes during the development of an oceanic basin at ca. 0.59 Ma. After the tectonic inversion, these basin deposits reached high P-T metamorphic conditions, by subduction of the oceanic lithosphere, and were later exhumed as nappes over the basement. The Cabo Frio Tectonic Domain collided with the arc domain of the Ribeira Orogen at ca. 0.54 Ga. It is not an exotic block, but the eastern transition between this orogen and the Congo Craton. Almost 400 m.y. later, the South Atlantic rift zone followed roughly this suture, not coincidently. It shows how the Cabo Frio Tectonic Domain was reactivated as a continental margin in successive extensional and convergent events through geological time

Evidence For 2.35 To 2.30 Ga Juvenile Crustal Growth In The Northwest Borborema Province, Ne Brazil

The c. 600 Ma Brasiliano Borborema Province of NE Brazil comprises a complex collage of Precambrian crustal blocks cut by a series of continental-scale shear zones. The predominant basement rocks in the province are 2.1-2.0 Ga Transamazonian gneisses of both juvenile and reworked nature. U-Pb zircon and Sm-Nd whole-rock studies of tonalite-trondhjemite-granodiorite basement gneisses in the NW Ceará or Médio Coreaú domain in the northwestern part of the Borborema Province indicate that this represents a continental fragment formed by 2.35-2.30 Ga juvenile crust. This block has no apparent genetic affinity with any other basement gneisses in the Borborema Province, and it does not represent the tectonized margin of the c. 2.1-2.0 Ga São Luis Craton to the NW. The petrological and geochemical characteristics, as well as the Nd-isotopic signatures of these gneisses, are consistent with their genesis in an island arc setting. This finding documents a period of crustal growth during a period of the Earth's history which is known for its tectonic quiescence and paucity of crust formation. © Geological Society of London 2009.323271281Abreu, F.A.M., Lafon, J.M., Granulitos Transamazônicos no Cinturão de Cisalhamento Noroeste do Ceará (1991) Atas do XIV Simpósio de Geologia do Nordeste, 29, pp. 229-231Abreu, F.A.M., Hasui, Y., Gorayeb, P.S.S., Grábens eopaleozóicos do oeste cearense - considerações sobre as seqüências lito-estratigráficas (1993) Simpósio Geologia do Nordeste. 15. Atas, Boletim Núcleo Nordeste da SBG, 13, pp. 29-31Abouchami, W., Boher, M., Michard, A., Albar-Ede, F., A major 2.1 Ga old event of mafic magmatism in West Africa: an early stage of crustal accretion (1990) Journal of Geophysical Research, 95, pp. 17 605-17 629Almeida, F.F.M., Melcheer, G.C., Cordani, U.G., Kawashita, K., Vandoros, P., Radiometric age determinations from northern Brazil (1968) Boletim da Sociedade Brasileira de Geologia, 17, pp. 3-14Almeida, F.F.M., Hasui, Y., Brito Neves, B.B., Fuck, R.A., Brazilian structural provinces: an introduction (1981) Earth Science Reviews, 17, pp. 1-29Boher, M., Abouchami, W., Michard, A., Albarpde, F., Arndt, N.T., Crustal growth in West Africa at 2.1 Ga (1992) Journal of Geophysical Research, 97, pp. 345-369Brito Neves, B.B., (1975) Regionalização tectônica do precambriano nordestino, , Thesis, Universidade de São Paulo (unpublished)Brito Neves, B.B., Vandoros, P., Pessoa, D.A.R., Cordani, U., (1974) Reavaliação dos dados geocronológicos do Pré-Cambriano do Nordeste brasileiro, 6, pp. 261-271. , XXVIII Congresso Brasileiro de Geologia. Porto AlegreCaby, R., Precambrian terranes of Benin-Nigeria and northeast Brazil and the Late Proterozoic south Atlantic fit (1989) Terranes in the Circum-Atlantic Palaeozoic Orogens, 230, pp. 145-158. , Dallmeyer, R.D. (ed.) Geological Society of America, Special PaperCaby, R., Arthaud, M., Major Precambrian nappes of the Brazilian belt, Ceará, northeast Brazil (1986) Geology, 14, pp. 871-874Castro, N.A., Basei, M.A.S., Campos Neto, M.C., Geocronologia e evolução tectônica Proterozóica do Domínio Ceará Central (Região entre Madalena e Taperuaba, Província Borborema, NE do Brasil) (2004) Simp. 40 Anos de Geocronologia no Brasil, , USP-São Paulo, 74Cavalcante, J., de, C., Estratigrafia Precambriana do Estado do Ceará - Uma síntese (1993) Simpósio Geologia do Nordeste, 13, pp. 313-316. , 15. Atas. Natal, Boletim Núcleo Nordeste da SBGDantas, E.L., Van Schmus, W.R., The 3.4-3.5 Ga São José do Campestre Massif, NE Brazil: remnants of the oldest crust in South America (2004) Precambrian Research, 130, pp. 113-137Depaolo, D.J., A neodymium and strontium isotopic study of the Mesozoic calc-alkaline granitic batholiths of the Sierra Nevada and Peninsular Ranges, California (1981) Journal of Geophysical Research, 86, pp. 10 470-10 488Doumbia, S., Pouclet, A., Vidal, M., Kouamelan, A., Peucat, J.J., Vidal, M., Delor, C., Petrogenesis of juvenile-type Birimian (Palaeoproterozoic) granitoids in central Côte d'Ivoire, West Africa: geochemistry and geochronology (1998) Precambrian Research, 87, pp. 33-63Fetter, A.H., (1999) U-Pb and Sm-Nd constraints on the crustal framework and geologic history of Ceará State, NW Borborema Province, NE Brazil: implications for the assembly of Gondwana, , Ph.D. thesis, University of Kansas, USAFetter, A.H., Van Schmus, W.R., Dos Santos, T.J.S., Arthaud, M., Nogueira Neto, J.A., U-Pb and Sm-Nd geochronological constraints on the crustal evolution and basement architecture of Ceará State, NW Borborema Province, NE Brazil: implications for the existence of the Palaeoproterozoic supercontinent 'Atlantica' (2000) Revista Brasileira de Geociências, 30, pp. 102-106Fetter, A.H., Saraiva dos Santos, T.J., Evidence for Neoproterozoic continental arc magmatism in the Santa Quitéria batholith of Ceará State, NW Bornorema Province, NE Brazil: implications for the assembly of West Gondwana (2003) Gondwana Research, 6, pp. 265-273Gama, T., (1992) Geologia do setor nordeste da zona de cisalhamento de Granja - noroeste do Ceará, , Curso de Pós-graduação em Geociências, Universidade Federal do Pará. Ph.D. thesisGasquet, D., Barbey, P., Adou, M., Paquette, J.L., Structure, Sr-Nd isotope geochemistry and zircon U-Pb geochronology of the granitoids of the Dabakala area (Côte d'Ivoire): evidence for a 2.3 Ga crustal growth event in the Palaeoproterozoic of West Africa? (2003) Precambrian Research, 127, pp. 329-354Gaudette, H.E., Abreu, F.A.M., Lafon, J.M., Gorayeb, P.S.S., (1993) Evolução Transamazônica do cinturão de cisalhamento noroeste do Ceará: nova evidências geocronológicas, pp. 316-319. , XV Simpósio de Geologia do Nordeste, Resumos, NatalHackspacher, P.C., Santos, T.J.S., Lafon, J.M., (1991) Evolução geocronológica do complexo gnaissico-migmatítico do NW Ceará, pp. 268-271. , XIV Simpósio de Geologia do Nordeste, RecifeHartlaub, R.P., Heaman, L.M., Chacko, T., Ashton, K.E., Circa 2.3 Ga magmatism of the Arrowsmith Orogeny, Uranium City Region, Western Churchill Craton, Canada (2007) The Journal of Geology, 115, pp. 181-195Klein, E.L., Moura, C.A.V., Age constraints on granitoids and metavolcanic rocks of the São Luis Craton and Gurupi Belt, northern Brazil: implications for lithostratigraphy and geological evolution (2001) International Geology Review, 43, pp. 237-253Klein, E.L., Moura, C.A.V., Pinheiro, L.S., Palaeoproterozoic crustal evolution of the São Luis Craton, Brazil: evidence from zircon geochronology and Sm-Nd isotopes (2005) Gondwana Research, 8, pp. 177-186Krogh, T.E., A low contamination method for hydrothermal decomposition of zircon and extraction of U and Pb for isotopic age determinations (1973) Geochimica et Cosmochimica Acta, 37, pp. 485-494Krogh, T.E., Improved accuracy of U-Pb zircon ages by the creation of more concordant systems using an air abrasion technique (1982) Geochimica et Cosmochimica Acta, 46, pp. 637-649Ludwig, K.R., (2001) Isoplot/Ex (rev. 2.49), a geochronological toolkit for Microsoft Excel, , Berkeley Geochronology Center Special Publication No. 1a, University of California, BerkeleyMartins, G., Oliveira, E.P., Souza Filho, C.R., Lafon, J.M., Geochemistry and geochronology of the Algodões sequence, Ceará, NE Brazil: a Palaeoproterozoic magmatic arc in the Central Ceará domain of the Borborema Province? (1998) XL Congresso Brasileiro de Geologia, , Belo Horizonte, Anais, 28Monié, P., Caby, R., Arthaud, M.H., The Neoproterozoic Brasiliano orogeny in northeast Brazil: 40Ar/ 39Ar ages and petrostructural data from Ceará (1997) Precambrian Research, 81, pp. 241-264Nascimento, D.A., Gava, A., Pires, J.L., Teixeira, W., Geologia da folha sa 24-Fortaleza (1981) Projeto Radam Brasil, 21, pp. 23-212. , DNPM, Rio de JaneiroNogueira Neto, J.A., Evolução Metamórfica das Faixas Granulíticas de Granja e Cariré (NW do Ceará) (1996) Seminário de Pós-Graduação em Geociências, pp. 328-333. , Rio Claro. IGCE/UNESP. Res. ExpNogueira Neto, J.A., (2000) Evolução Geodinâmica das Faixas Granulíticas de Granja e Cariré, Extremo Noroeste da Província Borborema, , Ph.D. thesis, UNESP-Rio ClaroNogueira Neto, J.A., Marquesm F., Jr., Neri, T.F.O., Pedreira, L.H.S.T., Contribuição à geologia do município de Chaval (CE) (1989) Atas do XIII Simpósio de Geologia do NE, 11, pp. 27-28. , Fortaleza, SBG, BolNovaes, F.R.G., Brito Neves, B.B., Kawashita, K., Reconhecimento cronoestratigráfico da região nordeste do Estado do Ceará (1979) Atas do XI Simpósio de Geologia do NE, pp. 93-110. , NatalParrish, R.R., An improved micro-capsule for zircon dissolution in U-Pb geochronology (1987) Isotope Geoscience, 66, pp. 99-102Patchett, P.J., Ruiz, J., Nd isotopic ages of crust formation and metamorphism in the Precambrian of eastern and southern Mexico (1987) Contributions to Mineralogy and Petrology, 96, pp. 523-528Potrel, A., Peucat, J.J., Fanning, C.M., Archean crustal evolution of the West African Craton: example of the Amsaga Area (Reguibat Rise) U-Pb and Sm-Nd evidence for crustal growth and recycling (1998) Precambrian Research, 90, pp. 107-117Prado, F.S., Mendona, J.C.G., Moraes, J.B.A., Nedeiros, M.F., Andrade, P.R.S., Medeiros, R.P., (1981) ProjetoMartinópole, p. 5. , DNPM/CPRM, Relatório FinalSantos, T.J.S., (1993) Aspectos geológicos de uma área a sudoeste de Granja, região noroeste do Ceará, p. 159. , UNESP - Rio Claro. Dissertação de MestradoSantos, T.J.S., Souza, G.M., Queiroz, H.B., Nogueira Neto, J.A., Parente, C.V., Tafrogênese estateriana no embasamento palaeoproterozóico do NW da Província Borborema: Uma aboradagem petrográfica, geoquímica e geocronológica. In: XLI Congresso Brasileiro de Geologia, João Pessoa. 337 (2002) Actas V Symposium on South American Isotope Geology, pp. 1-4. , Argentina, 1-4Santos, T.J.S., Fetter, A.H., Neto, J.A.N., South American and African Pan-Gondwana correlations: the link between the northwestern part of the Borborema Province (NE Brazil) and southwestern Pharusian (Dahomey) belt (SW central Africa) (2008) West Gondwana: pre-Cenozoic correlations across the South Atlantic region, 294, pp. 101-119. , Pankhurst, R.J., Trouw, R.A.J., Brito Neves, B.B. & De Wit, M.J. (eds) Geological Society, London, Special Publicationsda Silva, L.C., Armstrong, R., Reavaliação da evolucão geológica em terrenos pré-cambrianos brasileiros com base em novos dados U-Pb SHRIMP, Parte III: províncias Borborema, Mantiqueira Meridional e Rio Negro-Juruena (2002) Revista Brasileira de Geociências, 32, pp. 529-544Stacey, J.S., Kramers, J.D., Approximation of terrestrial lead isotope evolution by a two stage model (1975) Earth and Planetary Science Letters, 26, pp. 207-251Steiger, R.H., Jäger, E., Subcommission on Geochronology: convention on the use of decay constants in geo-and cosmochronology (1977) Earth and Planetary Science Letters, 28, pp. 359-362Thiéblemont, D., Delor, C.M., A 3.5 Ga granite-gneiss basement in Guinea: further evidence for early archean accretion within the West African Craton (2001) Precambrian Research, 108, pp. 179-194Toteu, S.F., Van Schmus, W.R., Penaye, J., Nyobé, J.B., U-Pb and Sm-Nd evidence for Eburnian and Pan-African high-grade metamorphism in cratonic rocks of southern Cameroon (1994) Precambrian Research, 67, pp. 321-347Trompette, R., (1994) Geology of Western Gondwana, Pan-African - Brasiliano Aggregation of South America and Afric, p. 350. , A. 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Neoproterozoic Tectonic And Magmatic Episodes In The Nw Sector Of Borborema Province, Ne Brazil, During Assembly Of Western Gondwana

The Médio Coreaú domain of NE Brazil is located along the northwest margin of Borborema Province, the western branch of a Brasiliano/Pan-African collisional belt that formed during the assembly of Western Gondwana. The early Paleoproterozoic basement of the Médio Coreaú domain is composed of migmatitic gneisses and juvenile granulites, overlain by late Paleoproterozoic and Neoproterozoic rocks intruded by syn- to post-tectonic Brasiliano granitoids. According to integrated structural and geochronological data (U-Pb zircon and monazite ages), the Neoproterozoic tectonic evolution of the Médio Coreaú is characterized by low-angle thrusting and transcurrent deformation. U-Pb geochronological data from plutons intruded during this compressional regime indicate the collisional evolution began at approximately 622 Ma and continued until about 591 Ma. The continuation of convergence until approximately 560 Ma resulted in the formation of NE-SW and E-W shear zones within the Borborema Province and adjoining West African provinces. The final stage of the ductile tectonism was characterized by uplift and high-angle fault generation between approximately 560 and 545 Ma. The last tectonic event was an extensional phase, resulting in the formation of the Jaibaras graben and intrusion of post-orogenic granites at around 532 Ma. © 2007 Elsevier Ltd. All rights reserved.253271284Almeida, F.F.M., Hasui, Y., Brito Neves, B.B., Fuck, R.A., Brazilian structural provinces: an introduction (1981) Earth Science Reviews, 17, pp. 1-29Boher, M., Abouchami, W., Michard, A., Albarede, F., Arndt, N.T., Crustal Growth in West Africa at 2.1 Ga (1992) Journal Geophysics Research, 97, pp. 345-369Brito Neves, B.B., 1975. Regionalização geotectônica do pré-Cambriano nordestino. Thesis, Universidade de São Paulo, p. 198Brito Neves, B.B., 1983. O mapa geológico do nordeste oriental do Brasil, Escala 1;1.000.000. Thesis, Livre docência, Universidade de São Paulo, p. 177Brito Neves, B.B., Cordani, U.G., Tectonic evolution of South America during the Late Proterozoic (1991) Precambrian Research, 53, pp. 23-40Brito Neves, B.B., dos Santos, E.J., Van Schmus, W.R., 2000. Tectonic history of the Borborema Province, northeastern Brazil. In: U. Cordani, E.J. Milani, A. Thomaz Filho, Campos, D.A. (Eds.), Tectonic Evolution of South America. Proceedings of the Thirty-first International Geological Congress, Rio de Janeiro, Brazil, pp. 151-182Brito Neves, B.B., Van Schmus, W.R., Fetter, A.H., North-western Africa-North-eastern Brazil. Major tectonic links and correlation problems (2002) Journal of African Earth Sciences, 34, pp. 275-278Brown, M., Solar, G.S., Granite ascent and emplacement during contractional deformation in convergent orogens (1998) Journal of Structural Geology, 20, pp. 1365-1393Caby, R., 1989. Precambrian terrane of Benin-Nigeria and northeast Brazil and Proterozoic Atlantic fit barks. Geological Soc. of America, Special paper, 230, pp. 145-158Caby, R., Arthaud, M.H., Major Precambrian nappes of the Brazilian Belts, Ceará, Northeast Brazil (1986) Geology, 14, pp. 871-874Caby, R., Arthaud, M.H., Archanjo, C.J., Lithostratigraphy and petrostructural characterization of supracrustal units in Brasiliano Belt of Northeast Brazil: geodynamic implications (1995) Journal of South American Earth Sciences, 8, pp. 235-246Caby, R., Sial, A.N., Arthaud, M.H., Vauchez, A., Crustal evolution and the Brasiliano orogeny northeast Brazil (1991) The West African orogens and circum-Atlantic correlative, pp. 373-397. , Dallmeyer R.D., and Lécorché J.P. (Eds), Springer-VerlagCastaing, C., Feybesse, J.L., Thiéblemont, C., Triboulet, C., Chevremont, P., Paleogeographical reconstructions of the Pan-Africano/Brasiliano Orogen: closure of an oceanic domain or intracontinental convergence between major blocks? (1994) Precambrian Research, 69, pp. 327-344Castro, N.A., Basei, M.A.S., Sato, K., 2003. Nd data from Central Ceará Domain: Archean relics, Paleoproterozoic record and Neoproterozoic crustal reworking. In: Proceedings IV Symposium on South American Isotope Geology, Brazil, pp. 160-163Cavalcanti, J., Ferreira, C.A., 1983. Mapa Geológico do Estado do Ceará. Scale 1:500,000, MME/CPRM - BrasíliaCosta, M.J., França, J.B., Bacchiegga, I.F., Habekost, C.R. Cruz, W.B. da, 1973. Geologia da Bacia JaibarasCeará, Piauí e Maranhão. Projeto Jaibaras. DNPM/CPRM. Relatório final (5 vols.)Dantas, E.L., Van Schmus, W.R., Hackspacher, P.C., Fetter, A.H., Brito Neves, B.B., Cordani, U., Nutman, A.P., Williams, I.S., The 3.4-3.5 Ga São José do Campestre massif, NE Brazil: remnants of the oldest crust in South America (2004) Precambrian Research, 130, pp. 113-137Djouadi, M.T., Gleizes, G., Ferré, E., Bouchez, J.L., Caby, R., Lesquer, A., Oblique magmatic structures of two epizonal granite plutons, Hoggar, Algeria: late-orogenic emplacement in a transcurrent orogen (1997) Tectonophysics, 279, pp. 351-374Duguet, M., Faure, M., Granitoid emplacement during a thrusting event: structural analysis, microstructure and quartz c-axis patterns. An example from Hercynian plutons in the French Massif Central (2004) Journal of Structural Geology, 26 (5), pp. 927-945Ferré, E.C., Caby, R., Peucat, J.J., Capdevila, R., Monié, P., Pan-African, post-collisional, ferro-potassic granite and quartz-monzonite plutons of Eastern Nigeria (1998) Lithos, 45 (1-4), pp. 255-279Ferreira, V.P., Sial, A.N., Jardim de Sá, E.F., Geochemical and isotopic signatures of Proterozoic granitoids in terranes of the Borborema structural province, northeastern Brazil (1998) Journal of South American Earth Sciences, 11 (5), pp. 439-455Fetter, A.H., 1999. U-Pb and Sm-Nd Geochronological constraints on the crustal framework and geological history of Ceará State, NW Borborema Province, NE Brazil: implications for the assembly of Gondwana. University of Kansas, Ph.D. thesis, 164 ppFetter, A.H., dos Santos, T.J.S., Van Schmus, W.R., Hackspacher, P.C., Brito Neves, B.B., Arthaud, M.H., Nogueira Neto, J.A., Wernick, E., Evidence for Neoproterozoic continental arc magmatism in the Santa Quitéria batholith of Ceará State, NW Borborema Province, NE Brazil: implications for assembly of West Gondwana (2003) Gondwana Research, 6, pp. 265-273Fetter, A.H., Van Schmus, W.R., dos Santos, T.J.S., Arthaud, M.H., Nogueira Neto, J.A., 1997. Geologic history and framework of Ceará State: northwest Borborema Province, NE Brazil. South American Symposium on Isotope geology, Brazil, Extended Abstracts, pp. 112-114Fetter, A.H., Van Schmus, W.R., dos Santos, T.J.S., Arthaud, M., Nogueira Neto, J.A., 2000. U-Pb and Sm-Nd geochronological constraints on the crustal evolution and basement architecture of Ceará State, NW Borborema Province, NE Brazil: implications for the existence of the Paleoproterozoic supercontinent "Atlantica". 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De Geociência, Universidade de Brasília, Ph.D. thesis, 803pKrogh, T.E., A low contamination method for hydrothermal decomposition of zircon and extraction of U and Pb for isotopic age determinations (1973) Geochimica et Cosmochimica Acta, 37, pp. 485-494Krogh, T.E., Improved accuracy of U-Pb zircon ages by the creation of more concordant systems using an air abrasion technique (1982) Geochimica et Cosmochimica Acta, 46, pp. 637-649Ludwig, K.R., 1993. ISOPLOT - A plotting and regression program for radiogenic-isotope data: version 2.70. U.S. Geological Survey Open-File Report 91-445, 42pMacedo, M.H.P., Sá, J.M., Kawashita, K., A idade da faixa Orós: resultados preliminares (1988) Revista Brasileira de Geociências, 18, pp. 1-24Monié, P., Caby, R., Arthaud, M.H., The Neoproterozoic Brasiliano Orogeny in Northeast Brazil: 40Ar/39Ar and petrostructural data from Ceará (1997) Precambrian Research, 81, pp. 241-264Nascimento, D.A., Gava, A., Pires, J.L., Teixeira, W., 1981. Geologia da folha sa 24 - Fortaleza. In: Projeto Radam Brasil. DNPM, Rio de Janeiro. vol. 21, 23-212Neves, S.P., Mariano, G., Assessing the tectonic significance of a large-scale transcurrent shear zone system: the Pernambuco lineament, northeastern Brazil (1999) Journal of Structural Geology, 21 (10), pp. 1369-1383Neves, S.P., Vauchez, A., Feraud, G., Tectono-thermal evolution, magma emplacement, and shear zone development in the Caruaru area (Borborema Province, NE Brazil) (2000) Precambrian Research, 99 (1-2), pp. 1-32NogueiraNeto, J.A., Marques Jr., F., Néri, T.F.O., Pedreira, L.H.S.T., 1989. Contribuição à geologia do município de Chaval (CE). Atas do XIII Simpósio de Geologia do NE. Fortaleza, SBG, 11, 27-28Oliveira, D.C., Stratigraphic interplays between igneous and sedimentary events in the Early Paleozoic Jaibaras trough (Northeast Brazil) (2000) Revista Brasileira de Geociências, 30 (3), pp. 423-427Oliveira, D.C., Mohriak, W.U., Jaibaras trough: an important element in the early tectonic evolution of the Parnaíba interior sag basin, Northern Brazil) (2003) Marine and petroleum geology, 20, pp. 351-383Paquette, J.L., Caby, R., Djouadi, M.T., Bouchez, J.L., U-Pb dating of the end of the Pan-African orogeny in the Tuareg shield: the post-collisional syn-shear Tioueine pluton (Western Hoggar, Algeria) (1998) Lithos, 45 (1-4), pp. 245-253Parrish, R.R., U-Pb of monazite and its application to geological problems (1990) Canada Journal of Earth Science, 27, pp. 1431-1450Parrish, R.R., An improved micro-capsule for zircon dissolution in U-Pb geochronology (1987) Isotope Geoscience, 66, pp. 99-102Passchier, C.W., Trouw, R.A.J., (1996) Microtectonics, , Springer Verlag pp. 325Paterson, S.R., Vernon, R.H., Tobisch, O.T., A review of criteria for the identification of magmatic and tectonic foliations in granitoids (1989) Journal of Structural Geology, 11 (3), pp. 349-363Santos, T.J.S., 1993. Aspectos geológicos de uma área a sudoeste de Granja, NW do Ceará. Dissertação de mestrado, Instituto de Geociências e Ciências Exatas IGCE/UNESP-Rio Claro, São Paulo, p. 159Santos, T.J.S., 1999. Evolução Tectônica e Geocronológica do Extremo Noroeste da Província Borborema. PhD unpublished thesis, Instituto de Geociências e Ciências Exatas IGCE/UNESP-Rio Claro, São Paulo, 186pSantos, T.J.S., Hackspacher, P.C., 1991. Geologia do Grupo Martinópole, NW do Ceará. Anais do XXX Congresso Brasileiro de Geologia, São PauloSantos, T.J.S., Nogueira Neto, J.A., Fetter, A.H., Hackspacher, P.C., 2001. Petrografia e Litogeoquímica das Rochas do Embasamento Cristalino da Região de Granja - CE. Revista de Geologia (UFC) 14, pp. 33-48Santos, T.J.S., Santos, A.A., Dantas, E.L., Fuck, R.A., Parente, C.V., 2003. Nd Isotopes and the provenance of metasediments of the Itataia Group, northwest Borborema Province, NE Brazil. Proceedings of the IV Symposium on South American Isotope Geology, Brazil, pp. 286-289Santos, T.J.S., Souza, G.M., Queiroz, H.B., Nogueira Neto, J.A., Parente, C.V., 2002. Tafrogênese estateriana no embasamento paleoproterozóico do NW da Província Borborema: uma abordagem petrográfica, geoquímica e geocronológica. XLI Congresso Brasileiro de Geologia, João Pessoa, pp. 337-337Sial, A.N., Long, L.E., Figueiredo, M.H., Rare Earth element geochemistry of the Meruoca and Mucambo plutons, Ceará, Northeast Brazil (1981) Chemical Geology, 31, pp. 271-283Stacey, J.S., Kramers, J.D., Approximation of terrestrial lead isotope evolution by a two-stage model (1975) Earth and Planetary Science Letters, 26, pp. 207-221Steiger, R.H., Jäger, E., Subcommision on Geochronology: convention on the use of decay constants in geo- and cosmochronology (1977) Earth and Planetary Science Letters, 36, pp. 359-362Torquato, J.R., Cordani, V.G., Brazil-Africa geological links (1981) Earth Science Reviews, 17, pp. 155-176Trompette, R., (1994) Geology of western Gondwana Pan-African/Brasiliano aggregation of South America and Africa, , Brookfield: Balkema, Rotterdam 350pVan Schmus, W.R., Brito Neves, B.B., Hackspacher, P., Babinski, M., U/Pb and Sm/Nd geochronolgic studies of eastern Borborema Province, northeastern Brazil: initial conclusions (1995) Journal South America Earth Sciences, 8, pp. 267-288Van Schmus, W.R., Brito Neves, B.B., Hackspacher, P., Fetter, A.H., Dantas, E.L., Babinski, M., The Seridó Group of NE Brazil, a late Neoproterozoic pre- to syn-collisional basin in West Gondwana: insights from SHRIMP U-Pb detrital zircon ages and Sm-Nd crustal residence (TDM) ages (2003) Precambrian Research, 127, pp. 287-32

Structural And Geochronological Studies Of The Médio Coreaú Domain, Ne Brazil: Constraints On Brasiliano/pan-african Tectonic Evolution In The Nw Part Of The Borborema Province

Recent structural investigations and geochronological studies of rocks from the Médio Coreaú domain in the NW part of northeast Brazil's Borborema Province provide important constraints on the tectonic evolution of the region both preceeding and during the assembly of West Gondwana. Field observations of structural features and fabrics have revealed the presence of four distinct deformational phases in the MCD: D1, D2, D3 and D4. Only the early Paleoproterozoic gneisses record the D1 tectonic event and its preservation is cryptic owing to strong overprinting by the subsequent tectonic phases. The D2, D3 and D4 events affected younger supracrustal rocks and Neoproterzoic magmatic units, and U-Pb geochronological constraints show that all of these tectonic phases represent deformational events that occurred during Brasiliano collision between the West African craton and the NW part of the Borborema Province. The D2 phase, lasting between ca. 622 and 591 Ma, represents a frontal collision stage, which generated NW verging thrust-nappe systems, low-angle foliation, high-grade metamorphism and crustal anatexis. Transition to a strike-slip regime (D3) occurred at around 591 Ma when the region entered a phase of escape tectonics. During this time, the motion of crustal blocks towards NE and E was accommodated along numerous anastomosing shear zones. Syntectonic emplacement of granitoid plutons took place in transtensional domains of the shear zone system. The intrusion of late tectonic granitoids and rapid uplift and cooling of the orogen around 560 Ma as a result of D4 transpressional movements marked the end of the D3 transcurrent regime. These findings show that only the early Paleoproterozoic gneisses in the Médio Coreaú domain are polycyclic in nature. Rather than representing distinct orogenic events, the D2, D3 and D4 tectonic phases are a manifestation of progressive deformational events that developed in response to changes in the regional stress field during convergence and collision between the Borborema Province and its surrounding cratons.17Almeida, F.F.M., Hasui, Y., Brito Neves, B.B., Fuck, R.A., Brazilian structural provinces: An introduction (1981) Earth Science Reviews, 17, pp. 1-29Bouchez, J.L., Tubià, J.M., Mainprice, D., Déformation naturelle du quartz: Coexistence des systèmes de glissement de direction et à haute température (migmatites de la nappe d'Ojén, Espagne) (1985) Comptes Rendus De L'Académie Des Sciences De Paris, 301, pp. 841-846Brito Neves, B.B., dos Santos, E.J., Van Schmus, W.R., Tectonic history of the Borborema Province, northeastern Brazil (2000) Tectonic Evolution of South America. Proceedings of the Thirty-first International Geological Congress, pp. 151-182. , In: Cordani, U., Milani, E.J., Thomaz Filho, A., Campos, D.A. (Editors, Rio de Janeiro, BrazilBrito Neves, B.B., Van Schmus, W.R., Santos, E.J., Campos Neto, M.C., Kozuch, M., O evento Cariris Velhos na Província Borborema: Integração de dados, implicações e perspectivas (1995) Revista Brasileira De Geociências, 25, pp. 279-296Brito Neves, B.B., Campos Neto, M.C., Fuck, R.A., From Rodinia to Western Gondwana: An approach to the Brasiliano-Pan African Cycle and orogenic collage (1999) Episodes, 22, pp. 155-166Brito Neves, B.B., Cordani, U.G., Tectonic evolution of South America during the Late Proterozoic (1991) Crustal Evolution In the Late Proterozoic. Precambrian Research, 53, pp. 23-40. , In: R.J. Stern and W.R. Van Schmus (editors)Caby, R., Precambrian terrenes of Benin-Nigeria and northeast Brazil and the Late Proterozoic south Atlantic fit. Geological Society of America (1989) Special Paper, 230, pp. 145-158Caby, R., Arthaud, M.H., Archanjo, C.J., Lithostratigraphy and petrostructural characterization of supracrustal units in Brasiliano Belt of Northeast Brazil: Geodynamic implications (1995) Journal of South American Earth Sciences, 8, pp. 235-246Cavalcante, J., Ferreira, C.A., (1983) Mapa Geológico Do Estado Do Ceará. Scale 1:500.000, , MME/CPRM - BrasíliaCondie, K., (1989) Plate Tectonics and Crustal Evolution, p. 476. , Pergamon Press. Third edition, New YorkDantas, E.L., Hackspacher, P.C., Van Schmus, W.R., Brito Neves, B.B., Archean accretion in the São José do Campestre Massif, Borborema Province, Northeast Brazil (1998) Revista Brasileira De Geociências, 28, pp. 221-228Fetter, A.H., (1999) U-Pb and Sm-Nd Geochronological Constraints On the Crustal Framework and Geologic History of Ceará State, NW Borborema Province, NE Brazil: Implications For the Assembly of Gondwana, p. 164. , PhD thesis, Department of Geology, Kansas University, Lawrence, KS - USAFetter, A.H., Van Schmus, W.R., Santos, T.J.S., Arthaud, M., Nogueira Neto, J.A., U-Pb and Sm-Nd geochronological constraints on the crustal evolution and basement architecture of Ceará State, NW Borborema Province, NE Brazil: Implications for the existence of the Paleoproterozoic supercontinent "Atlantica" (2000) Revista Brasileira De Geociências, 30, pp. 102-106Fetter, A.H., Van Schmus, W.R., Santos, T.J.S., Arthaud, M., Nogueira Neto, J.A., (1997) Geologic History and Framework of Ceará State: Northwest Borborema Province, NE Brazil. South American Symposium On Isotope Geology, pp. 112-114. , Brazil, Extended AbstractsFetter, A.H., Santos, T.J.S., Nogueira Neto, J.A., Van Schmus, W.R., Geochronology U/Pb in zircon and Sm/Nd in total rock of the State of Ceará-results initials (1995) 16th Symposium of Geology of the Northeast, Recife. Sociedade Brasileira De Geociências, 14, pp. 418-422Fetter, A.H., Santos, T.J.S., Van Schmus, W.R., Hackspacher, P.C., Brito Neves, B.B., Arthaud, M.H., Nogueira, J.A., Wernick, E., Evidence for Neoproterozoic continental arc magmatism in the Santa Quitéria Batholith of Ceará State, NW Borborema Province, NE Brazil: Implications for the assembly of West Gondwana (2003) Gondwana Research, 6, pp. 265-273Guimarães, I.P., Almeida, C.N., Silva Filho, A.F., Araújo, J.M.M., Granitoids marking the end of the Brasiliano (Pan-African) orogeny within the central tectonic domain of the Borborema Province (2000) Revista Brasileira De Geociências, 30, pp. 177-181Hackspacher, P.C., Van Schmus, W.R., Dantas, E.L., Um embasamento Transamazônico na Provincia Borborema. XXXVI Congresso Brasileiro de Geologia (1990) Natal, 6, pp. 2683-2696Jardim de Sá, E.F., Fuck, R.A., Macedo, M.H.F., Peucat, J.J., Kawashita, K., Souza, Z.S., Bertrand, J.M., Pre-Brasiliano orogenic evolution in the Seridó belt, NE Brazil: Conflicting geochronological and structural data (1995) Revista Brasileira De Geociencias, 25, pp. 307-314Jardim de Sá, E.F., (1994) A Faixa Seridó (Província Borborema, NE Do Brasil) E O Seu Significado Geodinâmico Na Cadeia Brasiliana/Pan-Africana, , PhD Thesis, Universidade de Brasilia, Brasilia, DF, BrazilLister, G.S., Hobbs, B.E., The simulation of fabric development during plastic deformation and its application to quartzite: The in-uence of deformation history (1980) Journal of Structural Geology, 2, pp. 355-370Law, R.D., Crystallographic fabrics: A selective review of their application to research in structural geology (1990) Deformation Mechanisms, Rheology and Tectonics. Geological Society of London, Special Publication, 54, pp. 335-352Mainprice, D., Bouchez, J.L., Blumenfeld, P., Tubià, J.M., Dominant slip in naturally deformed quartz: Implications for dramatic plastic softening at high temperature (1986) Geology, 14, pp. 819-822Monié, P., Caby, R., Arthaud, M.H., Timing of the Neoproterozoic Brasiliano orogeny in northeast Brazil: 40Ar/39Ar ages and petrostructural data from Ceará (1997) Precambrian Research, 81, pp. 241-264Passchier, C.W., Trouw, R.A.J., (1996) Micro-tectonics, , Springer, BerlinSantos, T.J.S., (1999) Evolução Tectônica E Geocronológica Do Extremo Noroeste Da Província Borborema, p. 186. , PhD Thesis, Instituto de Geociências e Ciências Exatas IGCE/UNESP-Rio Claro, SP, BrazilSantos, T.J.S., Nogueira Neto, J.A., Fetter, A.H., Hackspacher, P.C., Petrografia e Litogeoquímica das Rochas do Embasamento Cristalino da Região de Granja-CE (2001) Revista De Geologia (UFC), 14, pp. 33-48Sá, J.M., McReath, I., Leterrier, J., Petrology, geochemistry and geodynamic setting of Proterozoic Igneous Suites of the Orós fold belt, Borborema Province, Northeast Brazil (1995) Journal of South American Earth Science, 8, pp. 299-314Sial, A.N., Ferreira, V.P., Almeida, A.R., Romano, A.W., Parente, C.V., Costa, M.L., Carbon isotope fluctuations in Precambrian carbonate sequences of several localities in Brazil (2000) Anais Da Academia Brasileira De Ciências, 72, pp. 539-558Silva Filho, A.F., Guimarães, I.P., Van Schmus, W.R., Crustal evolution of the Pernambuco-Alagoas Complex, Borborema Province, NE Brazil: Nd isotopic data from Neoproterozoic granitoids (2002) Gondwana Research, 5, pp. 409-422Torquato, J.R., Cordani, V.G., Brazil-Africa geological links (1981) Earth Science Reviews, 17, pp. 155-176Toteu, S.F., Van Schmus, W.R., Penaye, J., Nyobe, J.B., U-Pb and Sm-Nd evidence for Eburnian and Pan-African high-grade metamorphism in cratonic rocks in southern Cameroon (1994) Precambrian Research, 67, pp. 321-347Trompette, R., (1994) Geology of Western Gondwana, Pan-African-Brasiliano Aggregation of South America and Africa, p. 350. , A.A. Balkema, Rotterdam, BrookfieldVan Schmus, W.R., Brito Neves, B.B., Hackspacher, P.C., Babinski, M., U/Pb and Sm-Nd geochronologic studies of the eastern Borborema Province, Northeastern Brazil: Initial conclusions (1995) Journal of South American Earth Science, 8, pp. 267-288Van Schmus, W.R.V., Brito Neves, B.B., Williams, I.S., Hackspacher, P.C., Fetter, A.H., Dantas, E.L., Babinski, M., The Seridó Group of NE Brazil, a late Neoproterozoic pre-to syn collisional basin in Western Gondwana: Insights from SHRIMP U-Pb detrital zircon ages and Sm-Nd residence (TDM) ages (2003) Precambrian Research, 127, pp. 287-327Weinberg, R.F., Sial, A.N., Mariano, G., Plutons and shear zones in the Borborema Province, Brazil (2004) Geology, 32, pp. 377-38

Correlation of Byrd and Selborne Groups, with implications for the Byrd Glacier discontinuity, central Transantarctic Mountains, Antarctica

South of Byrd Glacier, central Transantarctic Mountains, Antarctica, Lower Cambrian Shackleton Limestone (Byrd Group) is divided into four informal members. The transition from Shackleton carbonates to clastics of Starshot Formation is conformable, with alternating units of limestone and argillite, and a thick succession of pillow basalt. Douglas Conglomerate is interbedded with and overlies Starshot Formation, and overlies folded Shackleton Limestone unconformably. Lower amphibolite-grade Selborne Group is composed of Madison Marble and Contortion Schist. The contact between the two formations is interbedded marble and schist, and includes metabasalt. We correlate Byrd Group with Selborne Group, Shackleton Limestone with Madison Marble, and Starshot Formation and Douglas Conglomerate with Contortion Schist. These correlations and the lack of equivalent lithologies to the north of Byrd Glacier imply that Byrd Glacier is the northern boundary of the Byrd depositional basin, and reinforces the notion that it marks a major tectonic discontinuity crossing the Ross Orogen

First evidence of a “Barrovian”-type metamorphic regime in the Ross orogen of the Byrd Glacier area, central Transantarctic Mountains

The Selborne Group comprises two metamorphic rock units, the muscovitedolomite bearing Madison Marble and the biotite-muscovitequartz-calcite Contortion Schist, which contains thick lenses of variably deformed metabasalts and metaconglomerates. Petrological and structural data indicate a polyphase metamorphic evolution including: i) an early stage of upper greenschist regional metamorphism (P = 0.15–0.3 GPa; T = 380–450°C), ii) prograde metamorphism during D1 up to amphibolite facies peak conditions (P = 0.58–0.8 GPa, T = 560–645°C), iii) syn-D2 unloading-cooling retrograde metamorphism, iv) a post-D2 contact metamorphic overprint at variable T between 450 and 550°C and 0.2 GPa connected to the emplacement of granitic plutons and felsic dyke swarms. Geochronological data constrain the polyphase syn-D1/D2 evolution between 510 and 492 Ma. A similar metamorphic path, including a medium P stage but at lower T conditions, is documented in greenschist facies metabasalts within the Byrd Group in the Mount Dick area. The metamorphic pattern and close lithostratigraphic matching between Selborne Group and Byrd Group sharply contrast with the high-grade Horney Formation that is exposed north of the Byrd Glacier and corroborate the hypothesis that the Byrd Glacier discontinuity marks a first-order crustal tectonic boundary crossing the Ross orogen