Kei Sato

Universidade de São Paulo

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MÂ

Miguel Ângelo Stipp Basei

Universidade de São Paulo

Oswaldo Siga Júnior

Universidade de São Paulo

Umberto G. Cordani

Magna Graecia University

Colombo Celso Gaeta Tassinari

Universidade de São Paulo

Leonardo Fadel Cury

Universidade Federal do Paraná

Cláudia Regina Passarelli

Universidade de São Paulo

Ian McReath

Universidade de São Paulo

M. Santosh

University of Adelaide

Wilson Teixeira

Universidade de São Paulo

Allen P. Nutman

University of Wollongong

Cooperative Institutions

Instituto de Geociencias

Universidade de São Paulo

Serviço Geológico do Brasil - CPRM

Consejo Nacional de Investigaciones Científicas y Técnicas

National Council for Scientific and Technological Development

Massachusetts Institute of Technology

Universidade Federal do Rio Grande do Sul

Universidade Federal do Paraná

Universidade do Estado do Rio de Janeiro

University of Lisbon

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High P-T phase relation of magnesian (Mg0.7Fe0.3) staurolite compositon in the system FeO-MgO-Al2O3-SiO2-H2O: Implications for prograde high-pressure history of ultrahigh-temperature metamorphic rocks

American Mineralogist (2009)

Kei Sato M. Santosh Toshiaki Tsunogae

High-pressure and high-temperature phase relation on Mg0.74Fe0.26-staurolite composition with excess water in the system FeO-MgO-Al2O3-SiO2-H2O was experimentally determined at 12-19 kbar and 850-1050 °C, with a focus on the lower-pressure stability limit of magnesian staurolite. The experimental results show that the stability field of staurolite in the system shifts to higher temperatures as compared to that of pure-Mg staurolite. At 950 °C, the lower-pressure stability limit is located between 15 and 14 kbar. This study demonstrates that staurolite breaks down with isothermal decompression by a series of reactions at 950 °C: St → Opx + Crn + Melt and St + Opx → Spr + Melt. The Mg' [=Mg/(Fe+Mg)] of staurolite in the former reaction is 0.7. When staurolite coexists with orthopyroxene in run products, the staurolite Mg' is decreased to 0.6-0.5. Moderate-Mg staurolite (Mg' = ~0.5) in natural occurrences has been reported as inclusion minerals in poikiloblastic garnets within ultrahigh-temperature (UHT) metamorphic rocks from major collisional orogenic belts in southern India and southern Africa. The experimental data presented in our study suggest the possibility that the staurolite-bearing UHT metamorphic rocks had experienced high-pressure metamorphism and/or UHT extreme metamorphism during the prograde metamorphic stage.

Staurolite

10.2138/am.2010.3170

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Citations (15)

Idades U-Pb (Zircões) de 1.75 Ga em granitóides alcalinos deformados dos núcleos Betara e Tigre: evidências de regimes extensionais do estateriano na Faixa Apiaí

Geologia USP Série Científica (2002)

Leonardo Fadel Cury Gilberto Alexander Kaulfuss Oswaldo Siga Júnior Miguel Ângelo Stipp Basei Ossama Mohamed Harara

Geochronological study of deformed alkaline rocks belonging to the NE-SW oriented ellipsoidal Betara and Tigre basement nuclei, located in the midst of metavolcanossedimentary rocks of the Apiaí Belt provide new data on superimposed tectonic events of regions complex geological history. Protomylonitic, mylonitic and ultramylonitic syenogranites predominate and exhibit lithogeochemical characters of anorogenic 'A' type granites. U-Pb (zircon) dating indicates Paleoproterozoic ages of 1748 ± 5.4 Ma in the Betara Nuclei and 1772 ± 9.5 Ma in the Tigre Nuclei. These Statherian ages represent an important regional benchmark. Ages between 1600 Ma and 1800 Ma, predominantly associated with extensional processes, are recognized mainly in the eastern-central portion of the South American continent where they are interpreted as representing the age of rupture of the Paleoproterozoic Atlantic Supercontinent.

Supercontinent

Basement

10.5327/s1519-874x2002000100009

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Citations (40)

Mesoproterozoic mantle heterogeneity in the SW Amazonian Craton

Taylor & Francis eBooks (2006)

Gilmar José Rizzotto Jorge Silva Bettencourt Wilson Teixeira Kei Sato Artur Takashi Onoe

10.1201/noe0415398992.ch8

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Citations (10)

Geology and Rb-Sr geochronology of granitoids of Sierra Grande, province of Río Negro

Revista de la Asociación Geológica Argentina (2009)

Ricardo Varela Kei Sato Pablo Diego González Ana María Sato Miguel Ângelo Stipp Basei

Geochronology

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In situ isotopic analyses of U and Pb in zircon by remotely operated SHRIMP II, and Hf by LA-ICP-MS: an example of dating and genetic evolution of zircon by 176Hf/177Hf from the Ita quarry in the Atuba Complex, SE Brazil

Geologia USP Série Científica (2009)

Kei Sato Oswaldo Siga Júnior Josiane Aline da Silva Ian McReath Dunyi Liu

Operar o espectrômetro de massa SHRIMP à distância, remotamente via Internet, é sem dúvida uma técnica alternativa de grande interesse para a datação de cristais de zircão. Embora não represente avanço no método geocronológico U-Pb em zircão, a técnica de operação remota traz, além de facilidade, grande economia nesse tipo de análise. Foi executada pela primeira vez em análises espectrométicas envolvendo dois laboratoratórios internacionais (São Paulo, Brasil - Beijing, China) possibilitando a obtenção de resultados em tempo real. O procedimento foi aplicado em três amostras de rochas gnáissico-migmatíticas da pedreira Ita (próxima à cidade de Curitiba - Paraná - Brasil) pertencentes ao Complexo Atuba. Tais rochas, quando analisadas através do método U-Pb (TIMS) demonstraram uma evolução complexa, com idades bastante imprecisas. A presença de importantes heranças arqueanas e paleoproterozoicas, neste complexo, foram confirmadas nas zonas internas de cristais de zircão obtidas em leucossomas neoproterozoicos. Análises adicionais realizadas em rochas dioríticas indicaram ser intrusivas, e não encaixantes, e apresentaram idades relacionadas às colisões continentais (0.6 Ga) envolvidas durante a assembléia de Gondwana, no Neoproterozoico. A determinação das razões de isótopos de Hf em cristais de zircão, por meio de LA-ICP-MS, representa uma nova opção para checar a importância relativa da contribuição de material do manto (εHf >; 0) e crosta (εHf < 0). No Complexo Atuba, o componente arqueano sugere derivação de material oriundo do manto (εHf +1,5 a +8,7), enquanto o componente paleoproterozoico indica contribuição crustal (εHf -9,1 a -10,1).

10.5327/z1519-874x2009000300004

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Citations (46)

Constraining timing and P-T conditions of continental collision and late overprinting in the Southern Brasília Orogen (SE-Brazil): U-Pb zircon ages and geothermobarometry of the Andrelândia Nappe System

Precambrian Research (2017)

Mariana Barroso Coelho Rudolph Allard Johannes Trouw Carlos E. Ganade Rodrigo Vinagre Júlio Cézar Mendes

Orogeny

continental collision

Geothermobarometry

Basement

10.1016/j.precamres.2017.02.001

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Citations (64)

Carbonic metamorphism at ultrahigh-temperatures: Evidence from North China Craton

Earth and Planetary Science Letters (2007)

M. Santosh Toshiaki Tsunogae Hiroharu OHYAMA Kei Sato Jiahao Li

10.1016/j.epsl.2007.10.058

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Citations (139)

Trace element geochemistry and Sr-Nd characteristics of Mesoproterozoic mafic intrusive rocks from Rondônia, Brazil, SW Amazonian Craton: Petrogenetic and tectonic inferences

Episodes (2008)

Vicente Antônio Vitório Girardi Wilson Teixeira Jorge Silva Bettencourt Selma Maffei de Andrade Margareth Sugano Navarro

sequence intruded by 1.10-1.02Ga metadiabases, gabbros, meta-gabbros, and amphibolites associated with granitic plutons (bimodal magmatism).The original tholeiitic magmas, derived from a depleted source (! Nd(T) = +3.1 to +5.0), in a proto-oceanic setting, underwent subsequent contamination by the host rocks, as indicated by the isotopic and trace element data.

Felsic

Underplating

10.18814/epiiugs/2008/v31i4/004

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Citations (8)

Metabasic rocks from the Itaiacoca group: U-Pb zircon ages and tectonic implications, southern Brazil

Abstracts (2004)

Oswaldo Siga Júnior Miguel Ângelo Stipp Basei Cláudia Regina Passarelli Kei Sato Hélcio Prazeres Filho

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High-pressure and ultrahigh-temperature metamorphism at Komateri, northern Madurai Block, southern India

Journal of Asian Earth Sciences (2008)

Toshiaki Tsunogae M. Santosh Hiroyuki Ohyama Kei Sato

10.1016/j.jseaes.2008.02.004

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Citations (69)