Rômulo Machado

Universidade de São Paulo

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Aléxis Rosa Nummer

Universidade Federal Rural do Rio de Janeiro

Nolan Maia Dehler

Petrobras (Brazil)

Ruy Paulo Philipp

Universidade Federal do Rio Grande do Sul

Tiago da Rocha Karniol

Instituto de Geociencias

Gélson Luís Fambrini

Universidade Federal de Pernambuco

Patrícia Duringer Jacques

Serviço Geológico do Brasil - CPRM

Essaïd Bilal

Mines Saint-Étienne

Cláudio Riccomini

Universidade de São Paulo

Renato Paes de Almeida

Universidade de São Paulo

Ian McReath

Universidade de São Paulo

Cooperative Institutions

Instituto de Geociencias

Universidade de São Paulo

Hospital Universitário da Universidade de São Paulo

National Council for Scientific and Technological Development

Universidade Brasil

Universidade Federal de Mato Grosso do Sul

Universidad San Pedro

Instituto Geológico

Secretaria do Meio Ambiente

Universidade Federal do Rio Grande do Sul

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Ocorrência e Significado dos Septos do Embasamento Encontrados nas Suítes Graníticas do Batólito Pelotas, RS, Brasil

Pesquisas em Geociências (2002)

Ruy Paulo Philipp Rômulo Machado

The Pelotas Batholith situated in the eastern part of Sul-rio-grandense Shield is NE oriented and has dimensions of about 400 x 120 km. It is a granitic belt with six main suites: Pinheiro Machado Suite, Erval Suite, Viamão Suite, Encruzilhada do Sul Suite, Cordilheira Suite and Dom Feliciano Suite. The development of a continental collision whose evolution started by the end of Neoproterozoic, 635-610Ma, and reached 550Ma, is registered in the granitic suites. Most granitoids are syn to late-collisional, which have their emplacement controlled initially by low- to mid-angle shear zones and lately by sub-vertical transcurrent shear zones. The last magmatic events produced alkaline and peralkaline granites and composite (acid and basic) dike swarms represent a postcollisional magmatism.During their ascension and emplacement these granitic units captured basement xenoliths sometimes with dimensions of several kilometers. Based upon petrographic, geochemical and structural data these xenoliths were compared with the metamorphic units that occur outside the batholith. Their similarity suggest that the batholith, in spite of being limited by shear zones, is very close to its original setting. The interaction of xenoliths with the granitic magma produced primary structures that reflect the conditions during the ascent and emplacement of granitic bodies and contribute to the understanding of the geotectonic evolution in the eastern part of Sul-rio-grandense Shield.

Batholith

Peralkaline rock

Xenolith

10.22456/1807-9806.19597

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Citations (20)

The Camaquã extensional basin: Neoproterozoic to early Cambrian sequences in southernmost Brazil

Brazilian Journal of Geology (2000)

Antônio Romalino Santos Fragoso-Cesar Gélson Luís Fambrini Renato Paes de Almeida Ana Paula Meireles Reis Pelosi Liliane Janikian

The Camaqua Basin is an extensional post-orogenic and pre-cratonic rift system of Neoproterozoic-Early Cambrian age located in the Gaucho Shield, Rio Grande do Sul, southernmost Brazil. The basin is divided into a series of small sub-basins which were filled with the Camaqua Group, a thick (>9,000 m) unit composed of three formations: (i) the siliciclastic Marica Formation, (ii) the volcano-sedimentary Crespos Formation and (iii) the siliciclastic Santa Barbara Formation. These units correspond to three major stratigraphic sequences, and are divided into higher order sequences. Provenance and paleocurrent analysis of the siliciclastic deposits show a close relationship of the sourcearea with the lithologies that occur today in the neighborhood of these deposits, suggesting that no important lateral transport took place along the border faults. Paleocurrent measurements indicate a northern position for the marine body that cyclically invaded the basin.

Paleocurrent

Siliciclastic

10.5327/rbg.v30i3.847

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Citations (23)

Processamento digital e interpretação geológica de imagens TM-LANDSAT na região das minas de Camaquã, estado do Rio Grande do Sul

Anais da Academia Brasileira de Ciências (1996)

de Almeida Teodoro Isnard Ribeiro Fambrini Gelson Luis Branco Fabio Cardinale da Silva Filho Wellington Ferreira Sayeg Heitor Siqueira

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Magnetic Llineaments at the eastern edge of the Paraná basin in Santa Catarina and its correlation with phanerozoic Tectonics

Brazilian Journal of Geology (2014)

Patrícia Duringer Jacques Rômulo Machado Roberto Gusmão de Oliveira Francisco José Fonseca Ferreira Luís Gustavo de Castro

The magnetic lineaments at the Eastern Edge of the Parana Basin, in the central-southern region of the Santa Catarina State, show a main orientation pattern NE-SW and secondarily NNE-SSW. The NE-SW pattern reflects a framework of the ductile structures of the Santa Catarina Shield that continues in the substratum of the basin. The structural NNE pattern appears in the south of the Major Gercino Shear Zone and the NE pattern appears in the north of this structure. The data obtained shows that the structural NE-SW pattern of the basin, present in the shear zones Major Gercino and Itajai-Perimbo as well as in the Tijucas Terrain (Brusque Metamorphic Complex) in Santa Catarina, clearly extends underneath the Gondwanic sequence of the Parana Basin in the region. Amongst the obtained products by geophysical data processing in this work, what propitiated the best definition and distinction of the magnetic structures was the tilt angle of the total horizontal gradient method (TAHG). However the great flight lines spacing of the one of geophysical projects (7km) makes hard the identification of small magnetic structures, particularly in N-S and E-W directions. Such structural directions are referred to in previous works and were confirmed through the interpretation of SRTM images and studies of brittle structures in the field.

Lineament

10.5327/bjg.v44i1.29984

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Arcabouço estrutural e colocação sin-tectônica da suíte granítica Urucum durante o evento brasiliano: região do médio Rio Doce, Minas Gerais, Brasil

Anais (1997)

H A Nalini I Endo Rômulo Machado E Bilal

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Transpressive dextral shear in the Italva-Itaperuna section, Northern State of Rio de Janeiro, Brazil

Anais da Academia Brasileira de Ciências (2008)

Tiago R. Karniol Rômulo Machado Nolan Maia Dehler

Structural analysis carried out on a segment of the Neoproterozoic Ribeira Belt, southeastern Brazil, show that it represents part of the transpressive dextral orogen related to the Central Mantiqueira Province. NNE-trending and steeply dipping regional mylonitic belts form anastomosed geometry, and describe a map-scale, S-C-like structure that is characterized by their deflection towards NE near the Além Paraíba Lineament. Lithological and structural control related to deformation partition were responsible for the formation of felsic mylonitic granulites with S-type granites lenses developed in ductile shear zones, alternated with less deformed intermediate to basic granulites associated with charnockites. The dextral shear sense indicators are consistent with transpressive deformation in the region and are common especially at the border of the main shear zones. The presence of S-type leucogranite may lead to variations of linear and planar relationships, which result in local extension zones. These elements are consistent with oblique continental collision considering the São Francisco Craton as a stable block.

Mylonite

Felsic

Charnockite

Massif

10.1590/s0001-37652008000300016

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Citations (6)

Cinturão de cisalhamento Atlântico: um exemplo de tectônica transpressional neoproterozóica

Anais (1993)

Rômulo Machado I Endo

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PETROGRAFIA E GEOQUÍMICA DOS DIQUERS FÉLSICOS E MÁFICOS ASSOCIADOS AO BATÓLITO PELOTAS NA REGIÃO DE PIRATINI, RS

Revista Brasileira de Geociências (2006)

Celí Zanon Rômulo Machado Ruy Paulo Philipp

Petrographic studies on the mafic and felsic dykes from the Piratini region, RS, reveal a porphyritic texture with an aphanitic to fine-grained matriz, with glomeroporphyritic and spherulitic textures in the case of felsic, and ophitic to sub-ophitic with myrmekitic intergrowths in the case of mafic dykes. These dykes are intrusive in granitic rocks of the Pelotas Batholith along NW-SE and N-S trends associated with high angle shear zones. They are strongly metaluminous (mafic) and slighty metaluminous to peraluminous (felsic), with an alumina saturation index between 0.60 and 0,65 and 0,75 and 1,2, respectively. The Si02 content in the mafic dykes varies from 44 to 48 wt % and in the felsic varies from 67 to 75 wt %. The mafic dykes present higher Ti, Mg, Ca, Fe, Mn and P contents in comparison with the felsic dykes. The behavior of several major and trace elements (Fe, Mn, Mg, Ti, P, Ca and Sr, and, in minor degree, Ca and Mg show the importance of crystallization of iron-magnesium and feldspars in both dykes. The Nb/Ta e U/Th ratios of trace elements of these rocks show evidence of crustal contamination. The HREE display sub horizontallized patterns, showing Tb/Lu ratios from 1,5 to 2,7 in the samples of mafic dykes and from 1,6 to 2,5 in the felsic dykes. The samples have shown Lu concentration from 0,3 ppm to 0,6 ppm in mafic, and from 18 ppm to 41 ppm in the felsic dykes, respectively. The felsic dykes are more enriched in LREE, with La values from 73 ppm to 155 ppm, whereas mafic dykes present 18 ppm to 41 ppm of La and La/Sm ratios in the range of 3,0 to 5,0.

Felsic

Batholith

Porphyritic

10.25249/0375-7536.20063612334

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Citations (4)

Crustal zoning of Neoproterozoic pre-collisional granitoids in the Paraiba do Sul belt, Rio de Janeiro, Brazil

Brazilian Journal of Geology (2000)

Rômulo Machado Michel Démange Ian McReath Jacques Moutte

In the Rio de Janeiro State granites with associated charnockites or charnockitic suites are present in the Litorâneo domain in the internal part of the Paraiba do Sul belt, while plutons without charnockitic rocks occur in the Serra dos Orgaos and Paraiba domains in the external part. In both groups the linear and foliated batholiths are structurally concordant with the regional trends. The two associations usually have slightly expanded compositions with erogenic geochemical features, which are comparable with those for Cordilheran I-type batholiths, but are more evolved. Chemical differences found in the less-differentiated rocks of the two associations disappear in the most evolved terms. The lateral compositional zoning of the less-evolved terms across the belt could have been produced either by magma genesis above a NWdipping subduction zone, or by lateral migration of magmatism during tectonic evolution. The plutons were either emplaced at different, deep crustal levels under amphibolite or granulite facies conditions, or evolved in the presence of different fluids. The pre-collisional magmatism occurred between 560 and 634 Ma ago.

Batholith

10.5327/rbg.v30i1.762

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Citations (3)

Terrenos suspeitos a sul da placa sanfranciscana (SE da plataforma sul-americana)

Actas eBooks (1998)

Antonio Romalino Santos Fragoso Cesar Rômulo Machado R. P. Phillip F. M. Mello Issamu Endo

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Citations (1)