EVOLUÇÃO TECTÔNICA DO CINTURÃO DOM FELICIANO NO ESCUDO SUL-RIO-GRANDENSE: PARTE l - UMA CONTRIBUIÇÃO A PARTIR DO REGISTRO GEOLÓGICO

Abstract

A reappraisal of the geological basis of a Plate Tectonics model proposed for the tectonic evolution of the Dom Feliciano Belt in the Sul-rio-grandense Shield is presented under the light of a research programme in geology. Folio wing the presentation of a synthesis about the nature and structural characteristics of each geotectonic unit recognised, the main geotectonic models presented for this belt are discussed under the conceptual and substantive point of view. A discussion about the nature and advantages of an atualistic model for this belt is presented, being followed by a criticai evaluation of the geochronological and geophysical data recently obtained, the latter in the second part of this article.

Integrated evaluation of the geology, aerogammaspectrometry and aeromagnetometry of the Sul-Riograndense Shield, southernmost Brazil

“…The geology of the Sul-Riograndense Shield has been studied for one hundred years, most intensely in the last three decades, both by the Geological LÉO A. HARTMANN, WILLIAM R. LOPES and JAIRO F. SAVIAN Survey of Brazil (e.g., Bizzi et al 2003) and by university researchers, resulting in overviews by Jost and Hartmann (1984), Fragoso-César et al (1986), Fernandes et al (1992Fernandes et al ( , 1995a, Chemale et al (1995a, b), Hartmann et al (2000Hartmann et al ( , 2007, Chemale (2000), Basei et al (2000), Heilbron et al (2004), Philipp and Machado (2005), Saalmann et al (2011) and Philipp et al (2008Philipp et al ( , 2013. Field mapping was integrated in recent years with voluminous zircon dating, mostly with the sensitive high resolution ion microprobe (SHRIMP), so this portion of the Brazilian Shield is known to contain limited exposures of Archean rocks.…”

Alojamento do granito Lavras e a mineralização aurífera durante evolução de centro vulcano-plutônico pós-colisional, oeste do Escudo Sul-riograndense: dados geofísicos e estruturais

“…1B e 2A). No setor sul, as unidades mais antigas exibem trama desenvolvida segundo zonas de cisalhamento dúctil E-W a ENE-WSW de médio ângulo (Fernandes et al 1995), que evoluem a dúctil-rúpteis subverticais (Figs. 2A, 2C e 2D).…”

Lithogeochemistry of the meta-igneous units from Arroio Grande Ophiolitic Complex, southernmost Brazil

“…2). These granitoids are gray, have equigranular to porphyric textures, predominantly granodioritic composition, calc-alkaline affinity, U-Pb ages between 610 ± 5 and 612 ± 2 Ma and are interpreted as subduction-related active continental margin granitoids (Fernandes et al 1995;Babinski et al 1997;Philipp et al 2002;Ramos & Koester 2014). Within the Pinheiro Machado Complex, the Piratini Gneisses (metric to decametric xenoliths with tonalitic to granodioritic composition, U-Pb ages of 781 Ma) and the Basement Septa unit (mega-xenoliths of calc-silicate gneiss, biotite-rich gneiss, amphibolite, quartzite, and schist, U-Pb ages of 781 ± 5 Ma) are found and interpreted as Early Brasiliano crust remnants and Paleo to Mesoproterozoic basement septa (Fragoso César et al 1986;Figueiredo et al 1990;da Silva et al 1999;Wildner et al 2005).…”