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Previous issue date: 2014-02-26 / A ?rea estudada situa-se, geograficamente, no extremo NE do Estado do Rio Grande do Norte situados nos munic?pios de Taipu e Po?o Branco e geologicamente inseridos no Terreno Cristalino S?o Jos? do Campestre pertencente ? Prov?ncia Borborema, onde observando rela??es de campo, dados petrogr?ficos e geoqu?micos, permitiram individualizar tr?s pl?tons denominados: Gameleira, Taipu e Pitombeira.
O Pl?ton Gameleira ? composto por rochas granodior?ticas caracterizadas por fenocristais zonados de plagiocl?sios e tendo anfib?lio e biotita como m?ficos principais. Quimicamente, s?o rochas metaluminosas, de natureza c?lcio-alcalina e apresentam car?ter magnesiana. O Pl?ton Pitombeira ? composto por duas f?cies: (a) uma monzogran?tico ? sienogran?tica de textura grossa a porfir?tica caracterizada por fenocristais de K-feldspato e (b) uma de composi??o quartzo dior?tica a tonal?tica distinta por suas ripas de plagiocl?sio parcialmente zonadas e com borda de resfriamento. Quimicamente s?o rochas transicionais entre metaluminosas a peraluminosas, de natureza subalcalina (c?lcio-alcalina de alto K) e car?ter ferroso. Por fim, o Pl?ton Taipu ? formado por rochas monzogran?ticas a sienogran?ticas, contendo biotita como m?fico principal. S?o rochas peraluminosas, de natureza subalcalinas (c?lcio-alcalina de alto K) e car?ter ferroso.
No que se refere ?s an?lises de elementos terras raras (ETR), pode-se inferir que os tr?s pl?tons estudados apresentam anomalias negativas de Eu e enriquecimento em ETR leves, com raz?es de LaN/YbN entre 9,38 a 16,20 ppm (Pl?ton Gameleira), 17,99 a 31,39 ppm (f?cies gran?tica do Pl?ton Pitombeira), 14,15 a 21,81 ppm (f?cies dior?tica do Pl?ton Pitombeira) e 15,17 a 175,41 ppm (Pl?ton Taipu). Analisando os dados qu?micos e os diagramas em conjunto ? poss?vel sugerir que os pl?tons estudados pertencem a um ambiente tect?nico tardi a p?s-colisional.
Abstract
The studied area is geographically situated in the extreme northeastern of Rio Grande do Norte State located in the municipalities of Taipu and Po?o Branco and geologically entered in the Crystalline Land S?o Jos? do Campestre which belongs to Borborema Province, where by observing the field relations, petrographic and geochemical datas, has allowed to individualize three plutons named: Gameleira, Taipu and Pitombeira.
The Gameleira Pluton consists in granodioritic rocks characterized by phenocrysts zoned plagioclase having amphibole and biotite as the main mafic. Which are Chemically, metaluminous rocks, naturally from calc-alkaline and present magnesian character. The Pitombeira Pluton consists in two facies: (a) one monzogranite-syenogranite to coarse texture and to the porphyritic characterized by K-feldspar phenocrysts and (b) quartz dioric-tonalitic composition to a distinct for its laths of plagioclase partially zoned and also with cooling edges. Chemically are transitional rocks between metaluminous to peraluminous, naturally from subalkaline (high-K calc-alkaline) and ferrous character. Thus, the Taipu pluton is formed by monzagranitic-sienogranitic rocks, containing biotite as its main mafic. They are peraluminous rocks, naturally subalkaline (high-K calc-alkaline) and ferrous character.
As regards to the rare earth elements analysis (REE), which can be inferred that the three studied plutons exhibit negative anomalies of Eu and REE slight enrichment, with ratios of LaN / YbN between 9.38 to 16.20 ppm (Gameleira Pluton) 17.99 to 31.39 ppm (Pluton Pitombeira granitic facies), from 14.15 to 21.81 ppm (Pluton Pitombeira dioritic facies) and from 15.17 to 175.41 ppm (Pluton Taipu). Analyzing the chemical and diagrams datas to one another, it?s allowed to suggest that the studied plutons belong to a late tectonic environment to a post-collisional. / The studied area is situated in the northeastern extremity of the Rio Grande do
Norte State, between the municipalities of Taipu and Po?o Branco, and is geologically
inserted into the S?o Jos? do Campestre Crystalline Terrain within the Borborema
Province, where the analysis of field relationships, petrographic and geochemical data
allowed the distinction of three plutons named: Gameleira, Taipu and Pitombeira.
The Gamaleira Pluton is composed of granodioritic rocks characterized by zoned
plagioclase phenocrysts, with amphibole and biotite as the main mafic phases.
Geochemically, these are metaluminous rocks of calc-alkaline nature and magnesian
character. The Pitombeira Pluton encompasses two facies: (a) a coarse-grained to
porphyritic monzo- to syenogranitic facies marked by K-feldspar phenocrysts; and (b) a
quartz dioritic to tonalitic facies with partially zoned plagioclase laths showing chilled
rims. Geochemically, rocks of the monzo- to syenogranitic facies are transitional between
metaluminous and peraluminous, display a subalkaline nature (high K calc-alkaline) and a
ferroan character, whereas rocks of the quartz dioritic to tonalitic facies are metaluminous,
with shoshonitic affinity and ferroan character. Lastly, the Taipu Pluton is made of monzoto
syenogranitic rocks with biotite as the chief mafic mineral. They are peraluminous rocks
of subalkaline nature (high-K calc-alkaline) and ferroan character.
Regarding the rare-earth elements (REE), it is possible to conclude that the three
studied plutons display negative Eu anomalies and a relative enrichment of LREE over
HREE, with LaN/YbN ratios between 9.39 to 16.20 (Gameleira Pluton), 17.99 to 31.39
(granitic facies of the Pitombeira Pluton), 14.15 to 21.81 (dioritic facies of the Pitombeira
Pluton) and 15.17 to 175.41 (Taipu Pluton).
Based on the combined investigation of geochemical data and discrimination
tectonic diagrams, a late- to post-collisional tectonic environment is suggested for the
plutons here studied
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19459 |
| Date | 26 February 2014 |
| Creators | Oliveira, Maria Tatiany Duarte de |
| Contributors | 90459261487, http://lattes.cnpq.br/5356037408083015, Mariano, Gorki, 07019785387, http://lattes.cnpq.br/9480872229631779, S? , Jaziel Martins, 04595769415, http://lattes.cnpq.br/2772507532078148, Galindo, Antonio Carlos, Nascimento, Marcos Antonio Leite do |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM GEODIN?MICA E GEOF?SICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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