Navegando por Autor "RUIZ, Amarildo Salina"

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Batólito Guaporeí: uma extensão do Complexo Granitoide Pensamiento em Mato Grosso, SW do Cráton Amazônico
(2013-03) NALON, Patrícia Alves; SOUSA, Maria Zélia Aguiar de; RUIZ, Amarildo Salina; MACAMBIRA, Moacir José Buenano
The Guaporeí Batholith is located in the Vila Bela da Santíssima Trindade region, at Mato Grosso State (Brazil), and crops out over 240 km2 along the NW direction. It is situated in the Paraguá Terrane, included in the Rondonian-San Ignacio Province, in the southwestern portion of the Amazonian Craton. The batholith is made up of monzogranite, with subordinate granodiorite, quartz monzonite and syenogranite, shows coarse porphyritic/porphyroclastic texture, is metamorphosed in the greenschist facies and mylonitized along shear zones. The biotite is the main primary mafic mineral, sometimes associated with amphibole. Geochemical data indicated high-potassium calc-alkaline and metaluminous to peraluminous character, probably generated in continental arc environment, and evolved by fractional crystallization associated to crustal assimilation. Two stages of deformation related to the evolution of San Ignacio compressional orogeny were identified and are characterized by stretching and lineation, and development of S1 and S2 foliations. Dating by single zircon Pb-evaporation method yields a crystallization age of 1,314 ± 3 Ma, whereas Sm-Nd whole rock isotope data indicate a TDM model age of ca. 1.7 Ga and a negative value for εNd (t = 1,3) of -14, suggesting crustal contribution in the magma genesis. The obtained data indicate similarities between these rocks and those of the Pensamiento Granitoid Complex, in the Bolivian counterpart, and put in evidence that the Guaporeí Batholith is an extension of this complex.
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Cerro Porã Batholith: post-orogenic A-type granite from the Amoguijá Magmatic Arc - Rio ApaTerrane - South of the Amazonian Craton
(2013-09) PLENS, Dalila Pexe; RUIZ, Amarildo Salina; SOUSA, Maria Zélia Aguiar de; BATATA, Maria Elisa Fróes; LAFON, Jean Michel; BRITTES, Ana Flávia Nunes
The Cerro Porã Batholith has an approximately area of 30 km by 4 km, situated at the region of Porto Murtinho, Mato Grosso do Sul. It is located in Rio Apa Terrane, at the southern portion of the Amazonian Craton. It consists of Pink Syenogranitic Facies and Gray Monzogranitic Facies. The first facies is characterized by xenomorphic equigranular texture to essentially inequigranular texture with graphic and granophiric intergrowths. Both facies are composed of alkali feldspar, quartz, and plagioclase with biotite as the only primary mafic mineral. The Gray Monzogranitic Facies has porphyritic texture with graphic to granophiric fine-grained groundmass. It consists of quartz, plagioclase, alkali feldspar, and mafic aggregates (biotite and amphibole). Both facies were metamorphosed at greenschist facies and the Pink Syenogranitic Facies, which is milonytic in nature when it is in shear zones. One event of ductile–brittle deformation was identified, originated in a compressive system. It was responsible for the schistosity and mineral-stretching lineation. The development of the Esperança shear zone is related to this deformational phase and reflects the cinematic history of the reverse convergent system with top transport to NWW. Chemically, these rock types are classified as A2-type granitoids of range alkaline potassium saturated on silica. Geochronological data obtained by U-Pb (Sensitive High Resolution Ion Microprobe) method in zircon resulted in an age of 1749 ± 45 Ma, interpreted as crystallization age of the batholith. From the geotectonic point, the Cerro Porã Granite is considered to be the product of a magmatism associated with a magmatic arc developed in Statherian and emplaced in late-orogenic to post-orogenic stage.
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Geology and petrology of the Salto do Céu Suite: tectonic and stratigraphic implications on the SW Amazonian Craton
(Sociedade Brasileira de Geologia, 2018-09) MACAMBIRA, Moacir José Buenano; SOUSA, Maria Zélia Aguiar de; RUIZ, Amarildo Salina; BATATA, Maria Elisa Fróes; PIEROSAN, Ronaldo
The basic rocks of the Salto do Céu Suite outcrop as sills and flows in the southwestern Amazon Craton, Rondonian-San Ignacio Province, with an age of about 1.44 Ga. Sills are 2 to 30 m thick being hosted by pelites of the Aguapei Group. The flows are up to 5 m thick and cover this unit. Typical textures of magma mingling are observed near the contact with granites of Rio Branco Suite. The Rio Branco Intrusive Suite is composed of basic and acid rocks, as well as hybrid rocks that indicate mixing processes between basic and acids magmas. U-Pb (TIMS zircon) results indicate ages around 1.4 Ga for both terms. The Salto do Céu Suite rocks have tholeiites affinity classified as subalkaline and iron-rich tholeiitic basalts, with mg# values between 0.30 and 0.51. They can be separated into two groups, based on La N ; one is richer in ETR with La N greater than 100, while the other one has La N less than 100. Rocks of the Salto do Céu Suite and Rio Branco Suite are interpreted as a bimodal suites showing magma mingling features such as those developed in continental intraplate settings, extensional regime associated to the Columbia/Nuna breakup.
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Geology, Geochemistry, and Geochronology (U-Pb) of the Rio Fortuna Gneiss - Serra do Baú Intrusive Suite - Paraguá Terrane - SW Amazonian Craton
(2014-03) FARIA, Débora Almeida; RUIZ, Amarildo Salina; MATOS, João Batista; SOUSA, Maria Zélia Aguiar de; LIMA, Gabrielle Aparecida de; MACAMBIRA, Moacir José Buenano
The Rio Fortuna Gneiss crops out in the ¬Serra Santa Barbara, near the Fortuna military headquarters, on the Brazil-Bolivia border. These orthogneisses are located in a portion of the Paraguá terrain affected by the Sunsás Orogeny (1.0-0.9 Ga.). They are classified as monzo to granodiorite orthogneisses and underwent at least three episodes of deformation. The U-Pb zircon age of 1,711 ± 13 Ma obtained by laser ablation MC-ICP-MS is interpreted as the crystallization age of this orthogneiss. Geochemically, these rocks form a sequence comprising acidic subalkaline magmatism, calc-alkalic-type high-K, and metaluminous to peraluminous.
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Geology, petrology and geochronology (Pb-Pb) of the Serra da Bocaina Formation: evidence of an Orosirian Amoguijá Magmatic Arc in the Rio Apa Terrane, south of the Amazonian Craton
(2013-03) BRITTES, Ana Flávia Nunes; SOUSA, Maria Zélia Aguiar de; RUIZ, Amarildo Salina; BATATA, Maria Elisa Fróes; LAFON, Jean Michel; PLENS, Dalila Pexe
This work presents the results of the geological mapping and the petrological characterization of the Serra da Bocaina Formation belonging to the Amoguijá Magmatic Arc of the Rio Apa Terrain. In the Bocaina hills, the Serra da Bocaina Formation consists of intermediately to predominately acidic volcanic rocks, classified as andesites and rhyolites and subdivided into five petrographic facies, which include four volcanoclastics and one effusive. In the studied rocks, tectonic structures are generated in two compressive ductile to ductile-brittle deformational phases. The first phase, which is more intense, presents along the entire studied area and is responsible for the Santa Rosa Shear Belt, whereas the second phase is more localized. The geochemical study indicates a calc-alkaline magmatism of medium to high K, peraluminous, and generated in a volcanic arc environment. These volcanic rocks formed in an explosive environment related to the Amoguijá Magmatic Arc, as indicated by their Pb-Pb zircon age of 1877.3 ± 3.9 Ma.
Acesso aberto (Open Access)
Geology, petrology, U-Pb (shrimp) geochronology of the Morrinhos granite -Paraguá terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignácio orogeny
(2014-09) FRANÇA, Ohana; RUIZ, Amarildo Salina; SOUSA, Maria Zélia Aguiar de; BATATA, Maria Elisa Fróes; LAFON, Jean Michel
Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km2 long; it is located in the municipality of Vila Bela da Santíssima Trindade of the state of Mato Grosso, Brazil, in the Paraguá Terrane, Rondonian-San Ignácio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the greenschist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S1) and open folds (D2), and both phases were most likely related to the San Ignácio Orogeny. The geochronological (U-Pb SHRIMP) and isotopic (Sm-Nd) investigations of these rocks indicated a crystallization age of 1350 ± 12 Ma, TDM of approximately 1.77 Ga and εNd(1.35) with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian) continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignácio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite.
Acesso aberto (Open Access)
Gnaisse Turvo: registro de magmatismo paleoproterozoico no Terreno Paraguá - sudoeste do Cráton Amazônico, Vila Bela da Santíssima Trindade, Mato Grosso
(2013-06) FIGUEIREDO, Fernando Lisboa Pinto de; RUIZ, Amarildo Salina; SOUSA, Maria Zélia Aguiar de; MACAMBIRA, Moacir José Buenano
The Turvo Gneiss, object of this work, corresponds to a polideformed orthogneiss exposed in the region of Vila Bela da Santíssima Trindade, southwestern of state of Mato Grosso. From the tectonic point of view, is inserted into the Amazon Craton and represents the Paleoproterozoic basement of the Paraguá Terrain, one of the crustal blocks that form the Province Rondonian-San Ignacio (1.55 - 1.3 Ga). Two facies were identified from petrographic study: garnet-amphibole-biotite gneiss composed of granodiorite and biotite-amphibole gneiss, more abundant, with granodioritic to syenogranitic composition. The metamorphic paragenesis identified characterizes as responsible for these gneisses of amphibolite facies. The structural analysis features two stages of deformation in ductil crustal level. The oldest (F1) is responsible for developing the gneissic banding, while the structures of phase (F2), the second oriented N30-60W indicate compressive stress with tectonic transport from SW to NE. The minimum age of crystallization of the Turvo Gneiss defined by Pb-Pb method on zircon evaporation corresponds to 1651 ± 4 Ma and is interpreted as emplacement age of igneous protolith. The data indicate that significant lithogeochemical calcium-alkaline magmatism of high K, metaluminous to peraluminous, associated with magmatic evolution in a subduction environment (Lomas Manechis Orogeny - 1.7 to 1.6 Ga), dominated the period Estaterian in the Paraguá Terrain. The orthogneissic unit studied was later reworked, metamorphic and tectonic (F2), during the San Ignacio Orogeny (1.4 to 1.3 Ga).
Acesso aberto (Open Access)
Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS
(Universidade Federal do Pará, 2015-09) REDES, Letícia Alexandre; SOUSA, Maria Zélia Aguiar de; RUIZ, Amarildo Salina; LAFON, Jean Michel
The Taquaral Granite is located on southern Amazon Craton in the region of Corumbá, westernmost part of the Brazilian state of Mato Grosso do Sul (MS), near Brazil-Bolivia frontier. This intrusion of batholitic dimensions is partially covered by sedimentary rocks of the Urucum, Tamengo Bocaina and Pantanal formations and Alluvial Deposits. The rock types are classified as quartz-monzodiorites, granodiorites, quartz-monzonites, monzo and syenogranites. There are two groups of enclaves genetically and compositionally different: one corresponds to mafic xenoliths and the second is identified as felsic microgranular enclave. Two deformation phases are observed: one ductile (F1) and the other brittle (F2). Geochemical data indicate intermediate to acidic composition for these rocks and a medium to high-K, metaluminous to peraluminous calk-alkaline magmatism, suggesting also their emplacement into magmatic arc settings. SHRIMP zircon U-Pb geochronological data of these granites reveals a crystallization age of 1861 ± 5.3 Ma. Whole rock Sm-Nd analyses provided εNd(1,86 Ga) values of -1.48 and -1.28 and TDM model ages of 2.32 and 2.25 Ga, likely indicating a Ryacian crustal source. Here we conclude that Taquaral Granite represents a magmatic episode generated at the end of the Orosirian, as a part of the Amoguija Magmatic Arc.
Acesso aberto (Open Access)
Petrogenesis, U-Pb and Sm-Nd geochronology of the Furna Azul Migmatite: partial melting evidence during the San Ignácio Orogeny, Paraguá Terrane, SW Amazon Craton
(Universidade Federal do Pará, 2016-06) NASCIMENTO, Newton Diego Couto do; RUIZ, Amarildo Salina; PIEROSAN, Ronaldo; LIMA, Gabrielle Aparecida de; MATOS, João Batista; LAFON, Jean Michel; MOURA, Candido Augusto Veloso
The Furna Azul Migmatite is a ~10 km2 complex located in Pontes e Lacerda city, Mato Grosso, Brazil. It belongs to Paraguá Terrane, limit with Rio Alegre Terrane, southeast of San Ignacio Province, in Amazon Craton. It consists of transitional metatexites with amphibolite enclaves and dioritic injections. The rocks were divided in residuum rich and leucosome rich; both have three deformation phases marked by folded stromatic layers affected by spaced foliation and metamorphosed in amphibolite facies, represented by garnet, biotite, sillimanite, and by the clinopyroxene in the enclaves. The metamorphic retrograde to greenschist is marked by formation of chlorite, muscovite and prehnite. Residuum-rich metatexites show higher CaO and Na2O contents, separating them from K2O, Ba and Rb enriched transitional metatexites. U-Pb on zircon and Sm-Nd whole-rocks dating indicates that the residuum-rich metatexite crystallized at 1436 ± 11 Ma, with a TDM age of 1.90 Ga and εNd(1.43) of -0.54, whereas the dioritic injection crystallized at 1341,7 ± 17 Ma with a TDM age of 1.47 Ga and εNd(1.34) of 3.39. These results indicate that the Furna Azul Migmatite protolith was formed during the San Ignácio Orogeny and was reworked during the same orogeny, as basement for collisional to post-magmatic granites from Pensamiento Intrusive Suite.
Acesso aberto (Open Access)
Polyphase deformation and metamorphism of the Cuiabá group in the Poconé region (MT), Paraguay Fold and Thrust Belt: kinematic and tectonic implications
(Universidade Federal do Pará, 2015-03) VASCONCELOS, Bruno Rodrigo; RUIZ, Amarildo Salina; MATOS, João Batista
Several deformation models have been proposed for the Paraguay Belt, which primarily differ in the number of phases of deformation, direction of vergence and tectonic style. Structural features presented in this work indicate that the tectonics was dominated by low dip thrust sheets in an initial phase, followed by two progressive deformation phases. The first phase of deformation is characterized by a slate cleavage and axial plane of isoclinal recumbent folds with a NE axial direction, with a recrystallization of the minerals in the greenschist facies associated with horizontal shear zones with a top-to-the-SE sense of movement. The second stage shows vergence towards the NW, characterized by crenulation cleavage axial plane to F2 open folds over S0 and S1, locally associated with reverse faults. The third phase of deformation is characterized by subvertical faults and fractures with a NW direction showing sinistral movement, which are commonly filled by quartz veins. The collection of tectonic structures and metamorphic paragenesis described indicate that the most intense deformation at the deeper crustal level, greenschistfacies, occurred during F1, which accommodated significant crustal shortening through isoclinal recumbent folds and shear zones with low dip angles and hangwall movement to the SE, in a thin-skinned tectonic regime. The F2 deformation phase was less intense and had a brittle to ductile behavior that accommodated a slight shortening through normal open subvertical folds, and reverse faults developed in shallower crustal level, with vergence towards the Amazonian Craton. The third phase was less pervasive, and the shortening was accommodated by relief subvertical sinistral faults.