Gravimetric, radiometric, and magnetic susceptibility study of the Paleoproterozoic Redenção and Bannach plutons, eastern Amazonian Craton, Brazil: Implications for architecture and zoning of A-type granites

Geology, Geochemistry and Magmatic Evolution of the Paleoproterozoic, Anorogenic Oxidized a-Type Redencao Granite of the Jamon Suite, Eastern Amazonian Craton, Brazil

“…The occurrence of dike swarms that are coeval with the granites of the Jamon suite indicates that the granite plutons were emplaced in an extensional tectonic regime. This is consistent with the laccolithic shape of the Redenção pluton, suggested by gravity data (Oliveira et al 2008), which is dominant in rapakivi batholiths (Vigneresse 2005).…”

“…detailed discussion in Dall'Agnol & Oliveira 2007). They are anorogenic granites emplaced in an extensional setting (Oliveira et al 2008). Their origin is associated with anatexis of the lower crust due to underplating of mafic magma (Dall'Agnol et al 1999a.…”

Integrating airborne SAR, Landsat TM and airborne geophysics data for improving geological mapping in the Amazon region: the Cigano Granite, Carajás Province, Brazil

“…(6) The absence of outcrops in the contact zone of the pluton/country rocks makes it difficult to clarify the mechanism of the intrusion. Oliveira et al (2007), studying the Redençã o and Bannach Paleoproterozoic A-type plutons, exposed in the Rio Maria Granite-Greenstone Terrane and coeval of the Cigano pluton, presented geophysical evidence that those plutons have a sheet-like geometry and assumed that their emplacement was controlled by feeder dykes. A similar model can be proposed for the Cigano pluton.…”

IGCP Project 510 “A-type Granites and Related Rocks through Time”: Project vita, results, and contribution to granite research

“…2). In the Carajás province, in the southeastern Amazonian region, three distinct suites of 1.88 to 1.86 Ga A-type granites crosscut the Archean basement (Dall'Agnol and Oliveira, 2007;Dall'Agnol et al, 2005;Oliveira et al, 2008Oliveira et al, , 2009). In the Tapajós province, in the southern-central domain of the Amazonian craton (Lamarão et al, 2002), and in the southern part of the Guiana shield, near the border between Amazonas and Roraima states of Brazil Ferron et al, 2010;Valério et al, 2009), ca.…”

“…Proponents of regional extension relate the examined A-type granites to concurrent rupture events of the Karelian craton in Fennoscandia (also marked by emplacement of~2.4 Ga layered mafic intrusions; Lauri et al, 2006), rifting of the Paleoproterozoic Bhilwara aulacogen in northeastern India (Kaur et al, 2006), aborted rifting in the late-Paleoproterozoic in the Carajás province (Oliveira et al, 2008(Oliveira et al, , 2010 and in the Mesoproterozoic, in the Guyana shield (Fraga et al, 2009), Neoproterozoic rifting in the eastern part of the São Francisco craton (Rosa et al, 2007), lower Permian breakup of Gondwana in the Arabian-Nubian shield (Alirezaei and Hassanzadeh, 2012-this issue), lower Cretaceous extension in the North China craton (Yang et al, 2006), and deep mantle plume-related rupturing and rifting (in the advent of the opening of the South Atlantic) in southeastern Africa . These examples show that bimodal A-type granite associations are a typical phenomenon at the outset of the Wilson cycle and record continental rifting events (successful or failed) from the early Paleoproterozoic to the Phanerozoic.…”