Geologia e g??nese das ocorr??ncias de Ti, Nb e ETR???s Na Serra Repartimento, Roraima

Autor: Camaro, Carlos Andr??s Ballesteros
Přispěvatelé: David, Marta Edith Vel??squez, Salazar, Carlos Alejandro
Jazyk: portugalština
Rok vydání: 2017
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFAM
Universidade Federal do Amazonas (UFAM)
instacron:UFAM
Popis: Submitted by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-09-15T13:30:04Z No. of bitstreams: 2 Disserta????o - Carlos A. B. Camaro.pdf: 15636262 bytes, checksum: fc6232d3ff2ffe8291191325dbe08554 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Approved for entry into archive by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-09-15T13:30:16Z (GMT) No. of bitstreams: 2 Disserta????o - Carlos A. B. Camaro.pdf: 15636262 bytes, checksum: fc6232d3ff2ffe8291191325dbe08554 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Made available in DSpace on 2017-09-15T13:30:16Z (GMT). No. of bitstreams: 2 Disserta????o - Carlos A. B. Camaro.pdf: 15636262 bytes, checksum: fc6232d3ff2ffe8291191325dbe08554 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-05-17 CAPES - Coordena????o de Aperfei??oamento de Pessoal de N??vel Superior In the gneissic rocks of the Rio Urubu Metamorphic Suite that emerge in Serra Repartimento, with a metamorphic Sn foliation, and locally with meso to ultramilonitic textures, and milonitic Sn+1 foliation, would have been generated under conditions of amphibolite-granulite facies, at a metamorphic peak temperature of ~ 773 ??C and pressure of ~ 6,5 Kbar. Syn-kinematics plutons of gabbros settled during a tectonometamorphic event in the Orosiriano during the activation of shear zones, with crystallization conditions close to 1219 ??C and metamorphism in amphibolite facies with temperature of ~ 784 ??C and pressure of ~ 6,0 Kbar. The Mesozoic gneiss rocks were affected by tafrogenic processes, intruded by alkaline magmatism associated with the opening of the Tacutu graben, and hydrothermal alteration derived from the fluxo of hydrothermal fluids. These hydrothermal post-magmatic fluids related to alkaline plutonism, rich in Na, Ca, K, incompatible elements and light rare earth elements (LREE), migrated and percolated the metamorphic rocks, generating enrichment in Ti and Nb. Rutile in veins, accompanied with fluorapatitas and zircon, are minerals that enclose anomalous contents of these latter elements formed by processes of hydrothermal alteration. The chemical and physical characteristics of the fluids showed the existence of the interaction of at least two different compositional systems, an aqueous one characterized by the H2O-NaCl system and an aquocarbonic characterized by the H2O-CO2-NaCl system. This hydrothermal fluid presents salinity up to 22% by weight of NaCl, with a higher concentration in the range of 15-20%, with minimum entrapment conditions at 457 ??C and 3.3Kbars. The information obtained allows us to infer that the formation of the ore in the Serra Repartimento area is a result of a magmatic-hydrothermal system, with an alkaline magmatic source, with the transport of complex bonds of F-, Cl-, HCO3-, CO32-, HS- e S2??? and metals (Ti, Nb and REE's), probably associated with the Apia?? Alkaline Complex, and mobilized in fracture zones associated with reactivations of the NE-SW and E-W shear zones during Tacut?? graben formation. Nas rochas gn??issicas da Su??te Metam??rfica Rio Urubu que afloram na Serra Repartimento, com folia????o metam??rfica Sn, e localmente com texturas meso a ultramilon??tica, com folia????o milon??tica Sn+1, teriam sido geradas em condi????es de f??cies anfibolito-granulito, em temperatura de pico metam??rfico de ~773??C e press??o de ~6,5 Kbares. Pl??tons de gabro sin-cinem??ticos se acomodaram durante um evento tectonometam??rfico no Orosiriano durante a ativa????o de zonas de cisalhamento, sendo que as condi????es de cristaliza????o estiveram pr??ximas de 1219 ??C e as do metamorfismo em f??cies anfibolito com temperatura de ~784??C e press??o de ~6,0 Kbares. As rochas gn??issicas no Mesozoico foram afetadas por processos tafrog??nicos, intrudidas por magmatismo alcalino associado ?? abertura do graben de Tacutu, e altera????o hidrotermal derivadas da passagem de fluidos hidrotermais. Tais fluidos hidrotermais tardi-magm??ticos relacionados ao plutonismo alcalino, ricos em Na, Ca, K, elementos incompat??veis e elementos em terras raras leves (ETRL), migraram e percolaram as rochas metam??rficas, gerando enriquecimento em Ti a partir do metassomatismo alcalino nos gn??isses, e Nb e ETR???s associados a fluidos alc??linos. Rutilo em veios, al??m de fluorapatitas e zirc??o, s??o minerais que contem teores an??malos de desses elementos formados pelos processos de altera????o hidrotermal. As caracter??sticas f??sico-qu??micas dos fluidos mostraram a exist??ncia da intera????o de pelo menos dois sistemas composicionais diferentes, um aquoso caracterizado pelo sistema H2O-NaCl e um aquocarb??nico caracterizado pelo sistema H2O-CO2-NaCl. Esse fluido hidrotermal apresenta salinidade de at?? 22% em peso de NaCl, com maior concentra????o na faixa de 15 ??? 20%, com condi????es minimas de atrapamento a 457??C e 3,3 Kbares. As informa????es obtidas permitem inferir que a forma????o do min??rio na ??rea da Serra Repartimento ?? resultado de um sistema magmatico-hidrotermal, sendo a fonte magm??tica de caracter alcalino com transporte de complexos ligantes de F-, Cl-, HCO3-, CO32-, HS- e S2??? e metais (Ti, Nb e ETR???s), provavelmente associado ao Complexo Alcalino Apia??, e mobilizado em zonas de fratura associados a reativa??oes das zonas de cisalhamento NE-SW e E-W durante a forma????o do graben de Tacutu.
Databáze: OpenAIRE
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