Idades U-Pb (Zircões) de 1.75 Ga em granitóides alcalinos deformados dos núcleos Betara e Tigre: evidências de regimes extensionais do estateriano na Faixa Apiaí

Paleoproterozoic source contributions to the São Roque Group sedimentation: LA-MC-ICPMS U-Pb dating and Sm-Nd systematics of clasts from metaconglomerates of the Boturuna Formation

“…However, correlation with some parts of the São Francisco Craton seems improbable, since the Apiaí-São Roque Domain is thought to belong to a different paleocontinent (Paranapanema). It seems more probable, therefore, that equivalents are present in the basement of the Açungui Supergroup as exposed in the Tigre, Setuva and Betari nuclei, where orthogneisses of similar age are described (Kaulfuss, 2001;Cury et al, 2002;Siga Jr. et al, 2007). Remarkably, the latter are intruded by younger (~1.75 Ga) syenogranitic orthogneisses, which are considered to represent an extensional tectonic event (Kaulfuss, 2001;Siga Jr. et al, 2011) that is possibly equivalent to the one that generated the bimodal metavolcanic sequence of within-plate geochemical signature described in the SRG (Henrique-Pinto and Janasi, 2010).…”

Extensional and colisional magmatic records in the Apiaí Terrane, south-southeastern Brazil: integration of geochronological U-PB Zircon ages

“…The Betara Nucleus is considered by most authors to represent basement, and is composed almost exclusively of deformed granodiorite and syenogranite (Kaulfuss, 2001;Cury et al, 2002) which were affected by ductile to ductile-brittle shearing which produced the protomylonitic, mylonitic and ultramylonitic structures. The deformed granitoids are found in the centre-southern part of the studied area next to the Lancinha shear zone (Figure 1c).…”

“…In recent years, geochronologic studies has intensifi ed, signifi cantly contributing to the understanding of the stratigraphy of these terranes (e.g., Tassinari et al, 1990;Reis Neto, 1994;Daitx, 1996;Maniesi and Oliveira, 1997;Basei et al, 1992Basei et al, , 2003Basei et al, , 2008Siga Jr. et al, 1995, 2011a, 2011bSato and Siga Jr., 2001;Sato et al, 2003;Cury et al, 2002;Prazeres Filho et al, 2003a, 2003b, 2003cSalazar et al, 2004;Prazeres Filho, 2005;Campanha et al, 2004Campanha et al, , 2008aCampanha et al, , 2009Ribeiro, 2006;Weber et al, 2003;Oliveira et al, 2008). The presence of concordant metersized bodies of metabasic rocks in the metasedimentary rocks was fundamental to the geochronologic study of these sequences.…”

“…The rocks include quartzite, phyllite, schist, calc-silicate rocks, marbles and metamarls, as well as basic, intermediate and acid meta-igneous rocks. The basement to these sequences is exposed in the small Betara and Tigre Nuclei which are composed mainly of Archean and Paleoproterozoic metaigneous rocks (Kaulfuss, 2001;Cury et al, 2002;Prazeres Filho, 2005; Figure 1c).…”

“…The 630 -600 Ma Três Córregos and Cunhaporanga granite batholiths are believed to form part of magmatic arcs (Prazeres Filho et al, 2003a, 2003bPrazeres Filho, 2005). 580 -560 Ma late to post-tectonic granites intrude the metavolcanosedimentary sequences (Prazeres Filho, 2000;Cury et al, 2002;Figure 1c). The Lancinha Shear Zone would represent the surface trace of an important suture that separates the Apiaí Terrane from the terranes situated to the south of it (gneiss-migmatite rocks of the Atuba Complex; Siga Jr.…”