MARTINS, Douglas Teixeira. Geologia do terreno arqueano Granjeiro (3.4 a 2.6 Ga), Província Borborema. 2017. 52 f. Dissertação (Dissertação em Geologia)-Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by JOÃO CAVALCANTI JUNIOR (jbeniciojunior@yahoo.com.br) on 2017-10-09T17:18:01Z
No. of bitstreams: 1
2017_Dis_dtmartins.pdf: 126250655 bytes, checksum: 523fb6ce51df78ddef87d8c0679375a3 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-10-10T23:39:35Z (GMT) No. of bitstreams: 1
2017_Dis_dtmartins.pdf: 126250655 bytes, checksum: 523fb6ce51df78ddef87d8c0679375a3 (MD5) / Made available in DSpace on 2017-10-10T23:39:35Z (GMT). No. of bitstreams: 1
2017_Dis_dtmartins.pdf: 126250655 bytes, checksum: 523fb6ce51df78ddef87d8c0679375a3 (MD5)
Previous issue date: 2017 / The Archean Granjeiro terrain is located in the states Cear a, Piau and Pernambuco, being
partly covered by the Mesozoic sedimentary rocks of the Araripe Basin. It is subdivided
into two sections: the rst with direction E-W to the north, of the Patos Lineament, in
the south of the state of Cear a , consisting mainly of gneiss para- and ortoderived; end the
second with direction NE-SW south of the Patos Lineament, in the states of Piau and
Pernambuco, with a metaplutonic association of tonalitic to sienogranitic composition.
In both sections present an exhalative metavulcanosedimentary association interpreted as
remnant of oceanic crust. The chemical sedimentation of the crust originated the Banded
Iron Formations, being its greatest concentration and volume present in the region of the
of Curral Novo do Piau , more speci cally in the locality of Manga Velha. In this work, we
present new geochronological and deformational data of the host rocks of the Banded Ferriferous
Formations, to understand its lithostructural compartmentalization and tectonic
evolution. Two orthogneisses were dated by LA-SF-ICP-MS U-Pb in zircon: an of tonalitic
composition with age of 3.42 Ga and the other of sienogranitic composition with age
2.661 Ga. Geometric and kinematic structural analyzes, reveal at least four deformational
events (D1, D2, D3 e D4): D1, is related to the amalgamation phase of paleo-mesoarchean
blocks during the neoarchean; D2, event after 2.6 Ga possibly related to the closure of
a back arc basin, where the Banded Iron Formation were deposited; D3, deformational
phase related to the generation of Brasiliano-age shear zones of dextral transcurrence; D4,
the brittle deformation responsible for the generation of synthetic faults, which control
structurally the Banded Iron Formations and antithetic faults, which possibly served as
a conduit of hydrothermal
uids, hydrothermally enriching the ore. Based on the age of
the host rock and its stratigraphic relationships, it is proposed an age of approximately
2.5 Ga, for the sedimentation of the Banded Iron Formations. / O terreno arqueano Granjeiro localiza-se nos estados do Cear a, Piau e Pernambuco,
em parte encoberto pelas rochas sedimentares mesoz oicas da Bacia do Araripe.
E
subdividido em dois dom nios: o primeiro com dire c~ao E-W ao norte, do Lineamento
Patos, no sul do estado do Cear a, constitu do principalmente de gnaisse para- e ortoderivados;
e o segundo de dire c~ao NE-SW ao sul do Lineamento Patos, nos estados do
Piau e Pernambuco, com uma associa c~ao metaplut^onica de composi c~ao tonal tica a sienogran
tica. Em ambos os dom nios apresentam uma associa c~ao metavulcanossedimentar
exalativa interpretada como remanescente de crosta oce^anica. A sedimenta c~ao qu mica
desta crosta originou forma c~oes ferr feras bandadas, sendo a sua maior concentra c~ao e
volume presentes na regi~ao do munic pio de Curral Novo do Piau , mais especi camente
na localidade de Manga Velha. Neste trabalho apresentamos novos dados geocronol ogicos
e deformacionais das rochas encaixantes das forma c~oes ferr feras bandadas, a m de compreender
sua compartimenta c~ao lito-estrtural e evolu c~ao tect^onica do Terreno Granjeiro.
Foram datados dois ortognaisses por U-Pb LA-SF-ICP-MS em zirc~ao: um de composi c~ao
tonal tica com idade de 3,42 Ga e a outra de composi c~ao sienogran tica de idade 2,66
Ga. An alises estruturais geom etricas e cinem aticas revelam pelo menos quatro eventos
deformacionais (D1, D2, D3 e D4): D1, relaciona-se a fase de amalgama c~ao de blocos
paleo-mesoarqueanos durante o neoarqueano; D2, evento posterior a 2,6 Ga possivelmente
relacionado ao fechamento de uma bacia de back arc onde as Forma c~oes Ferr feras Bandadas
se depositaram; D3, fase deformacional relacionada a gera c~ao de zonas de cisalhamento
brasilianas de transcorr^encia destral; D4, deforma c~ao r uptil respons avel pela gera c~ao de
falhas sint eticas, que controlam estruturalmente as forma c~oes ferr feras bandadas e antit
eticas, que possivelmente serviram de conduto de
uidos hidrotermais, enriquecendo
hidrotermalmente o min erio. Com base na idade da rocha encaixante e suas rela c~oes estratigr
a cas prop~oe-se uma idade de aproximadamente de 2.5 Ga, para a sedimenta c~ao
das Forma c~oes Ferr feras Bandadas.
| Identifer | oai:union.ndltd.org:IBICT/oai:www.repositorio.ufc.br:riufc/26573 |
| Date | January 2017 |
| Creators | Martins, Douglas Teixeira |
| Contributors | Amaral, Wagner da Silva |
| 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 UFC, instname:Universidade Federal do Ceará, instacron:UFC |
| Rights | info:eu-repo/semantics/openAccess |
Page generated in 0.0031 seconds