Caracterização Dos Complexos Ortognáissicos Arqueanos De Goiás Por Gamaespectrometria Aérea

Abstract

CHARACTERIZATION OF THE ARCHEAN ORTOGNAISSE COMPLEXES OF GOIÁS BY AIRBORNE GAMMA-RAY SPECTROMETRY The Archean terranes of Goiás, Central Brazil, consist of 5 greenstone belts, and four complexes and one block of orthogneisses. The lithologic similarity among the complexes, inspite of their diferent ages, contribute significantly for their delimitation and interna subdivision during geologic maping. These dificulties may be eliminated by means of quantitatively interpreted aeroradiometric data.

The Paleoproterozoic Campinorte Arc: Tectonic evolution of a Central Brazil pre-Columbia orogeny

“…The drifting microcontinent hypothesis was first suggested by Brito Neves and Cordani (1991) in a South American tectonic review paper that contained a speculative sketch of Central Brazil paleoplates interaction. Following regional studies assumed the Crixás-Goiás Block as a microcontinent (Pimentel et al, 2000;Blum et al, 2003;Pimentel et al, 2004;Queiroz et al, 2008;Valeriano et al, 2008;Ferreira Filho et al, 2010). Marangoni et al (1995) published the first possible evidence supporting the microcontinent hypothesis, a sharp gravimetric contrast between the Campinorte and Cavalcante-Arraias Domains marked on surface by the Rio Maranhão Thrust (Marangoni et al, 1995;Pimentel et al, 2004).…”

Linking Gold Systems to the Crust-Mantle Evolution of Archean Crust in Central Brazil

“…2700 Ma, with crustal extension between 2500-2300 Ma [78], and closure of accretionary orogens between 2300-2050 Ma [11,15]. The TTG terranes of the GAB consist of intensely deformed orthogneisses of variable composition and age that were first delineated by gamma-spectrometry [79]. Compositionally, TTG orthogneisses vary from tonalite to granodiorite, with minor granite, charnockite, monzogranite, and adakite-like [12,23].…”

Airborne geophysical surveys in the north-central region of Goias (Brazil): implications for radiometric characterization of tropical soils

“…It has also been used for mapping area extent of geologic rock formations associated with such radioactive elements. Examples of such studies carried out in Brazil include the works of Blum et al (2003) and Sapucaia et al (2005). Measurements of gamma radiation at ground level provide information on the abundances of radioactive elements in the top soil layers.…”