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

Abstract

An integrated evaluation of geology, aerogammaspectrometry and aeromagnetometry of the Sul-Riograndense Shield is permitted by the advanced stage of understanding of the geology and geochronology of the southern Brazilian Shield and a 2010 airborne geophysical survey. Gamma rays are registered from the rocks near the surface and thus describe the distribution of major units in the shield, such as the Pelotas batholith, the juvenile São Gabriel terrane, the granulite-amphibolite facies Taquarembó terrane and the numerous granite intrusions in the foreland. Major structures are also observed, e.g., the Dorsal de Canguçu shear. Magnetic signals register near surface crustal compositions (analytic signal) and total crust composition (total magnetic signal), so their variation as measured indicates either shallow or whole crustal structures. The Caçapava shear is outstanding on the images as is the magnetic low along the N-S central portion of the shield. These integrated observations lead to the deepening of the understanding of the largest and even detailed structures of the Sul-Riograndense Shield, some to be correlated to fi eld geology in future studies. Most signifi cant is the presence of different provinces and their limits depending on the method used for data acquisition -geology, aerogammaspectrometry or aeromagnetometry.

Isotopic study of the Pb-Zn (Cu-Ag) Santa Maria Deposit, Caçapava do Sul Region, Rio Grande do Sul, Brazil

“…Although rocks of such an age are unknown in the Camaquã Basin and its basement, they possibly occur at greater depths. Similar ages were obtained in inherited detrital zircon crystals (1.2 to 1.0 Ga) in the Sul-Riograndense Shield, whose source has not yet been identified (Remus et al 1999, Hartmann et al 2016). An igneous/metamorphic old rock with galena was probably the lead source for the Camaquã and Santa Maria deposits.…”

Crono-correlação entre as Bacias do Camaquã (RS) e do Itajaí (SC): implicações Paleoambientais e Paleogeográfica

“…O CDF é resultado de sucessivos processos de colagem durante o Ciclo Brasiliano/Pan-Africano, os quais contribuıŕam para a amalgamação da porção sudoeste do paleocontinente Gondwana Ramos et al, 2018;e refs.). No ESRG, o CDF é composto pelos terrenos São Gabriel, Tijucas, Pelotas e Punta del Este, os quais são delimitados por descontinuidades geofıśicas de grande escala (Fernandes et al, 1995;Hartmann et al, 2016;e refs. ).…”

“…No estado do Rio Grande do Sul, o Escudo Sul-Rio-Grandense está posicionado no setor central-sul, contıńuo ao Escudo Uruguaio, sendo recoberto pela Bacia do Paraná, no norte, no oeste e em parte da porção sul, e pela seção emersa da Bacia de Pelotas, ao longo do litoral (Hartmann et al, 2016). O escudo está contido na Provıńcia Mantiqueira e integra o Escudo Brasileiro (Jost & Hartmann, 1984).…”

Capão do Leão Granite: Highly differentiated garnet‐bearing magmatism in the southeastern Dom Feliciano Belt, Brazil

“…To the east, the Dom Feliciano Belt is the main unit, divided into three major domains: western, central, and eastern (Figure 1a). These units are delimited by large‐scale geophysical discontinuities (Basei et al, 2018; Costa, 1997; Fernandes et al, 1995a,b; Girelli et al, 2018; Hartmann, Lopes, & Savian, 2016; Hueck, Oyhantçabal, Philipp, Basei, & Siegesmund, 2018; Philipp, Pimentel, & Chemale, 2016; Saalmann et al, 2011).…”