Koji Kawashita

Universidade de São Paulo

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Umberto G. Cordani

Magna Graecia University

Farid Chemale

Universidade do Vale do Rio dos Sinos

Colombo Celso Gaeta Tassinari

Universidade de São Paulo

Guilherme Mallmann

Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina

Wilson Teixeira

Universidade de São Paulo

Edinei Koester

Universidade Federal do Rio Grande do Sul

Ana Maria Pimentel Mizusaki

Universidade Federal do Rio Grande do Sul

Paul N. Taylor

Norsk Teknisk Museum

Rômmulo Vieira Conceição

Universidade Federal do Rio Grande do Sul

Reinhardt A. Fuck

Universidade de Brasília

Cooperative Institutions

Instituto de Geociencias

Universidade de São Paulo

Universidade Federal do Rio Grande do Sul

National Council for Scientific and Technological Development

Universidade Brasil

Universidade Estadual de Campinas (UNICAMP)

Hospital Universitário da Universidade de São Paulo

Universidade Estadual Paulista (Unesp)

Universidade Federal do Rio Grande

Petrobras (Brazil)

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Identification of local sources of lead in atmospheric deposits in an urban area in Southern Brazil using stable lead isotope ratios

Atmospheric Environment (2005)

Nicolai Mirlean D. Ashley Robinson Koji Kawashita M LIDIAVIGNOL Rômmulo Vieira Conceição

Lead (geology)

10.1016/j.atmosenv.2005.07.002

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Citations (33)

New isotopic ages and the timing of orogenic events in the Cordillera Darwin, southernmost Chilean Andes

Earth and Planetary Science Letters (1981)

Francisco Hervé Eric P. Nelson Koji Kawashita M. Suárez

Basement

Geochronology

Radiometric dating

10.1016/0012-821x(81)90105-9

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Citations (71)

PbPb, RbSr, and KAr systematics of the Lagoa Real uranium province (south-central Bahia, Brazil) and the Espinhaço cycle (ca. 1.5-1.0 Ga)

Journal of South American Earth Sciences (1992)

Umberto G. Cordani Brijesh Iyer Paul N. Taylor Koji Kawashita Kei Sato

Isochron dating

Geochronology

Radiometric dating

Basement

10.1016/0895-9811(92)90058-7

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Citations (74)

Combined stratigraphic and isotopic studies of Triassic strata, Cuyo Basin, Argentine Precordillera

Geological Society of America Bulletin (2006)

J Avila Farid Chemale Guilherme Mallmann Koji Kawashita Richard A. Armstrong

Research Article| September 01, 2006 Combined stratigraphic and isotopic studies of Triassic strata, Cuyo Basin, Argentine Precordillera J. N. Ávila; J. N. Ávila 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil Search for other works by this author on: GSW Google Scholar F. Chemale, Jr.; F. Chemale, Jr. 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil Search for other works by this author on: GSW Google Scholar G. Mallmann; G. Mallmann 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil Search for other works by this author on: GSW Google Scholar K. Kawashita; K. Kawashita 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil Search for other works by this author on: GSW Google Scholar R. A. Armstrong R. A. Armstrong 2Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information J. N. Ávila 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil F. Chemale, Jr. 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil G. Mallmann 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil K. Kawashita 1Laboratório de Geologia Isotópica, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501–970, Brazil R. A. Armstrong 2Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Publisher: Geological Society of America Received: 30 Aug 2005 Revision Received: 13 Feb 2006 Accepted: 03 Mar 2006 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2006) 118 (9-10): 1088–1098. https://doi.org/10.1130/B25893.1 Article history Received: 30 Aug 2005 Revision Received: 13 Feb 2006 Accepted: 03 Mar 2006 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation J. N. Ávila, F. Chemale, G. Mallmann, K. Kawashita, R. A. Armstrong; Combined stratigraphic and isotopic studies of Triassic strata, Cuyo Basin, Argentine Precordillera. GSA Bulletin 2006;; 118 (9-10): 1088–1098. doi: https://doi.org/10.1130/B25893.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The evolution of the Triassic–Cretaceous Cuyo Basin, located in the Andean Precordillera (NW Argentina), was mainly controlled by extensional–transtensional tectonics along NW-trending structures inherited from Paleozoic sutures. Stratigraphic and isotopic studies are herein presented in order to constrain the sedimentary infilling and source areas, as well as the age of Triassic strata related to the active faulted margin of the Cacheuta sub-basin. The whole stratigraphic package of the Cuyo Basin is interpreted as a second-order depositional sequence, comprising lowstand (alluvial fan deposits), transgressive (fluvial-deltaic and lacustrine deposits), and high-stand (oxidized lacustrine and high-sinuosity fluvial deposits) systems tracts. This stacking pattern was mainly controlled by the interplay between sedimentary influx and accommodation space, with important volcaniclastic contribution, especially during the early stages of basin development. Sm-Nd depleted-mantle model ages (TDM) for both basement and volcano-sedimentary samples range from 867 to 1345 Ma. All samples have negative ϵNd (t) values (−0.33 to −5.02). Basal deposits present older TDM model ages compared to intermediate-positioned deposits, and upper deposits present a wider range of model ages. This time-integrated factor correlates with paleo-current data, which indicate changes in the source areas through time. The Nd isotopic signature also suggests that sources of sediments for the Cacheuta sub-basin during the Triassic were restricted to units of Mesoproterozoic (Grenvillian) age, probably related to the Cuyania terrane. The U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon age of 243 ± 5 Ma, obtained in juvenile magmatic zircons from a lithoclast-free ignimbrite interlayered within the basal alluvial fan facies of the Cacheuta sub-basin, places the lowstand deposits in the Olenekian and establishes a potential chronostratigraphic horizon for future correlations. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Pica (typography)

10.1130/b25893.1

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Citations (51)

PENECONTEMPORANEOUS SYENITIC-PHONOLITIC AND BASIC-ULTRABASIC-CARBONATITIC ROCKS AT THE POÇOS DE CALDAS ALKALINE MASSIF, SE BRAZIL: GEOLOGIC AND GEOCHRONOLOGIC EVIDENCE

Brazilian Journal of Geology (2002)

H. Ulbrich Sílvio Roberto Farias Vlach Mabel N. C. Ulbrich Koji Kawashita

The large Pocos de Caldas alkaline massif, southeastern Brazil, is constituted mainly by felsic rocks (nepheline syenites, phonolites and subvolcanic tinguaites), associated with volcaniclastic basic-ultrabasic deposits. Critical appraisal of earlier K/Ar, Rb/Sr and microchemical ages (microprobe Th-U-total Pb determinations), combined with geological and paleomagnetic informations, can limit more adequately the age interval for the massif. A critical appraisal of the existing K/Ar data limit the age interval for the felsic rocks between 64 and 83 Ma, with a median value of 77 Ma. Earlier Rb/Sr data for various nepheline syenites result in isochron ages between 89 ± 8 and 83 ± 21 Ma (whole rock), while more recent determinations show 79 ± 7 Ma (internal isochron), with initial ratio of 0.70511 ± 0.00001. Nepheline syenites strongly affected by hydrothermal alteration were dated at 76 ± 2 Ma (Rb/Sr isochron), i.r. 0.7053 ± 0.0002. A phlogopite lamprophyre in the uranium open pit Osamu Utsumi mine yielded phlogopite Ar-Ar ages of 76 ± 1-2 Ma, close to a microprobe Th-U-total Pb age of thorite, 79 ± 3 Ma, found in carbonatite veins associated with lamprophyric-pyroxenitic dikes emplaced within nearby basement gneisses. These geochronologic data, together with geological-structural information and published magnetization directions, indicate that the felsic rocks were emplaced during a short time interval of perhaps 1-2 Ma, during the reverse 33r Campanian magnetization event (dated between 83 and 79.1 Ma). The vocaniclastic basic-ultrabasic deposits were emplaced, at least in part, during the following 33n magnetization event. All basic-ultrabasic occurrences in the district (the Vale do Quartel rocks, phlogopite lamprophyre dike in the open pit, pyroxenitic-carbonatitic dikes) seem to be related, and are in part somewhat younger than the felsic rocks or penecontemporaneous to them, partly accompanying the hydrothermal and mineralization event in the massif.

Felsic

Nepheline

Ultramafic rock

Massif

Nepheline syenite

10.5327/rbg.v32i1.957

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Citations (9)

Granitóides sinorogênicos Ca. 1,0 Ga na província Borborema, Ne do Brasil: dados geoquímicos e geocronológicos

Anais (1995)

Emanuel Ferraz Jardim de Sá Maria Helena De Freitas Macedo Reinhardt A. Fuck Koji Kawashita Jean Jacques Peucat

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EDADES Rb-Sr ROCA TOTAL DEL BATO LITO COMPUESTO DE LOS RIOS ELQUl-LIMARI A LA LATITUD 30°S.

Andean geology (2010)

Miguel A. Parada Francisco Munizaga Koji Kawashita

RESUMEN:Las edades Rb-Sr en roca total (isocronas de referencias) de 328±21 m.a., para las tonalitas-granodioritas, y de 197±5 m.a., para los leucogranitos del batolito compuesto de los rios Elqui-Limari, son concordantes con las relaciones estratigraficas y similares a aquellas de los ciclos plutonicos del Silurico-Carbonifero Inferior y Permico Superior-Triasico Inferior, definidos en la Cordillera Frontal y Precordillera de Mendoza. Las razones iniciales Sr87/Sr86 para los granitoides del Carbonifero Inferior (0,7058) y Triasico Inferior (0,7073) son compatibles con magmas generados a partir del manto superior, que han sufrido contaminacion cortical. Sin embargo, no se descarta la posibilidad de un origen cortical del magma Ieucogranitico.

10.5027/andgeov8n2-3-a07

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Citations (1)

Foramnifera as record for present-day ocean water Sr composition; procedures and mass spectrometry

Marcos Canto Machado Koji Kawashita Farid Chemale Karen Badaraco Costa Felipe Antonio de Lima Toledo

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Mantle diversity beneath the Colombian Andes, Northern Volcanic Zone: Constraints from Sr and Nd isotopes

Lithos (2005)

Andrés Rodríguez-Vargas Edinei Koester Guilherme Mallmann Rômmulo Vieira Conceição Koji Kawashita

Xenolith