Zobrazeno 1 - 10
of 77
pro vyhledávání: '"JEAN MICHEL LAFON"'
Autor:
Nayra Michelly das Chagas Souza, Jean Michel Lafon, João Marinho Milhomem Neto, Joelson Lima Soares
Publikováno v:
Brazilian Journal of Geology, Vol 54, Iss 1 (2024)
Abstract On the southern edge of the Amazonian Craton, the Mirassol d’Oeste and Guia formations constitute the cap carbonate of the Araras Group. Petrography, X-ray diffraction, and quantification of terrigenous material allowed the identification
Externí odkaz:
https://doaj.org/article/20d101bf4bf040a394213536f22a7c54
Publikováno v:
Journal of the Geological Survey of Brazil, Vol 3, Iss 2 (2020)
The gold mineralization at the Enche Concha and Tunel prospects, northwestern portion of the Gurupi Belt, is hosted in dacites and phyllites that belong to the ca. 2160 Ma-old metavolcano-sedimentary Chega Tudo Formation. These host rocks are variabl
Externí odkaz:
https://doaj.org/article/e6f189ea661d406087ed043313d8d291
Autor:
Cinthya Deus Souza, Maria Zélia Aguiar Sousa, Amarildo Salina Ruiz, Maria Elisa Fróes Batata, Ana Flávia Nunes Brittes, Jean Michel Lafon
Publikováno v:
Geochimica Brasiliensis, Vol 30, Iss 2, Pp 136-157 (2017)
The Serra da Bocaina Formation comprises Paleoproterozoic effusive and pyroclastic rocks displaying well preserved textures related to a plutonic-volcanic event recorded in the southern of the Amazonian Craton in the Rio Apa Terrane. This record sits
Externí odkaz:
https://doaj.org/article/c9777712903e400585a3f88248a05abf
Autor:
Elma Costa Oliveira, Jean Michel Lafon, José Augusto Martins Corrêa, Jully Hellen dos Santos Carvalho, Fabiana Ferrari Dias, Maria Helena Tirolo Taddei
Publikováno v:
Geochimica Brasiliensis, Vol 29, Iss 2, Pp 139-153 (2016)
Um estudo granulométrico, mineralógico e geoquímico dos sedimentos de fundo da margem oeste da baía do Guajará e do rio Carnapijó foi realizado para contribuir no monitoramento da degradação ambiental gradativa do sistema estuarino da região
Externí odkaz:
https://doaj.org/article/221933ebfc6c45c88a8e6abc956a6f54
Publikováno v:
Boletim do Museu Paraense Emílio Goeldi. Ciências Naturais, Vol 8, Iss 2, Pp 177-203 (2013)
This work presents mineralogical, geochemical and Pb isotope compositions of heavy metals from overbank sediments of the Amapari river and its tributaries, in the region of Serra do Navio, central Amapá. The sediments are mainly composed of quartz,
Externí odkaz:
https://doaj.org/article/cad135ae83d444798c3b9ace35cb4f17
Autor:
Lúcia Travassos da Rosa Costa, Evandro Fernandes de Lima, Jean Michel Lafon, Carla Joana Santos Barreto
Publikováno v:
Geologia USP. Série Científica, Vol 13, Iss 1, Pp 47-72 (2013)
The Iricoumé group consists of very well preserved pyroclastic and effusive volcanic rocks as a part of an extensive volcano-plutonic event, which marked the central part of the Amazonian craton during the Orosirian. Such rocks occur in the southern
Externí odkaz:
https://doaj.org/article/a047e17cf9ab45bab5d34d40c9a545f2
Autor:
Suziane Nascimento Santos, Jean Michel Lafon, José Augusto Martins Corrêa, Marly Babinski, Fabiana Ferrari Dias, Maria Helena Tirolo Taddei
Publikováno v:
Química Nova, Vol 35, Iss 2, Pp 249-256 (2012)
Lead analyses in bottom sediments from the hydrographic system of Belem (Para) indicated low contents of this metal for the sediments from the Guama river, with no significant anthropogenic contribution. A concentration of 18.1 ± 1.5 mg kg-1 and 206
Externí odkaz:
https://doaj.org/article/27fbe8249e6b4a479b2cf812ce9646c2
Autor:
Carla Joana Santos Barreto, Jean Michel Lafon, Lúcia Travassos da Rosa Costa, Evandro Fernandes de Lima
Publikováno v:
Geologia USP. Série Científica, Vol 13, Iss 1 (2013)
O Grupo Iricoumé compreende rochas vulcânicas efusivas e piroclásticas, com texturas e estruturas bastante preservadas, que pertence a um extenso evento vulcano-plutônico que marcou a região central do Cráton Amazônico durante o Orosiriano. Ta
Externí odkaz:
https://doaj.org/article/ab2c4514d4bd469e86acf5eb01d05254
Autor:
Carlos Augusto Sommer, Carla Joana S. Barreto, Jean Michel Lafon, Evandro Fernandes de Lima, Felipe Marcelo Alexandre, Farid Chemale Jr., Edinei Koester
Publikováno v:
Brazilian Journal of Geology, Vol 48, Iss 1, Pp 115-126
ABSTRACT: Sr-Nd-Pb isotopic signatures were determined for silica-undersaturated hypabyssal alkaline basic rocks of the Los Baldecitos Formation in the Cerro Morado area, situated in the Ischigualasto - Vale de la Luna Provincial Park (northernmost S
Externí odkaz:
https://doaj.org/article/fa29790468ff4da09044daf0ebd9bf0f
Autor:
Elma Costa Oliveira, Jean Michel Lafon, José Augusto Martins Corrêa, Jully Hellen dos Santos Carvalho
Publikováno v:
Brazilian Journal of Geology, Vol 46, Iss suppl 1, Pp 197-208
ABSTRACT: This study first aimed to evaluate the effect of human activities on the distribution of lead within the estuarine system of Belém, Pará. This was achieved by studying the concentration and isotopic signature of Pb in bottom sediments fro
Externí odkaz:
https://doaj.org/article/a8f9d27abfcc449e9c089ad7b7a4b4a6