Enxames de diques máficos do setor sul do Cráton do São Francisco - MG

Abstract

(1990, 1994

Magmatism, rifting and sedimentation related to Late Paleoproterozoic mantle plume events of Central and Southeastern Brazil

“…Dyke/wall rock contact features presented in Fig. 3 (explanation given in the legend), match with AMS results and show magma flow from NW to SE (Chaves, 2001). These facts seem to indicate a magma source centered at the NW end of the Pará de Minas swarm.…”

“…2 due to the aeromagnetic resolution used. On average, they are 5 km apart from each other in southern SFC keeping the same pattern under the cratonic cover in the Pirapora Graben (Chaves, 2001).…”

“…Ernst and Buchan (1997) proposed that mafic-ultramafic complexes can be fed from the system of a plume-related giant radiating dyke swarm and that they may be located either near or far from the plume center. Probably there is a correlation between the Pará de Minas swarm and dioritic/gabbronoritic rocks of the Barro Alto mafic-ultramafic complex, taking into account their ages and trace element chemistry (chemical data of Oliveira, 1993 andChaves, 2001). Rubin (1992) refers to close relationship between graben subsidence and dyke-induced faulting in Hawaiian volcanic rift zones.…”

Stratigraphy, tectonics and detrital zircon U-Pb (LA-ICP-MS) geochronology of the Rio Preto Belt and northern Paramirim corridor, NE, Brazil

“…8). In São Francisco Craton and adjacent orogenic belts, Tonian events are represented by the mafic dyke swarms of Ilhéus-Olivença-Camacã (1.0 Ga, Correa-Gomes & Oliveira 2000, Renne et al 1990), Salvador (924 Ma, U-Pb in badelleyte, Heaman 1991), Espinhaço Range (0.85 Ga, Dandefer et al 2009;Pedro Lessa Suite, 906 Ma, Machado et al 1989) and São Francisco Basin (tolleitic dykes with Sm-Nd age of 984±110 Ma, Chaves 2001, Chaves & Correia-Neves 2005. A-type granitic intrusions also occur in these regions, as exemplified by Salto da Divisa Suite (914-875 Ma, Silva et al 2008), in Minas Gerais State, and Serra da Pintada Suite (~969 Ma), in southern Piauí State.…”

Comportamento dos sistemas Sm-Nd e Rb-Sr da seqüência acamadada máfico-ultramáfica Ribeirão dos Motas (Arqueano), Cráton São Francisco Meridional: evidências de enriquecimento mantélico e fracionamento isotópico

“…Essa região é formada por um substrato siálico arqueano policíclico que hospeda várias seqüências supracrustais, além de rochas intrusivas e extrusivas ultramáficas, máficas e félsicas, geradas do Neoarqueano ao Neoproterozóico, circundado por cinturões móveis do Neoproterozóico (Carneiro et al, 1998a(Carneiro et al, , 1998bChaves, 2001;Teixeira et al, 1996Teixeira et al, , 1998Teixeira et al, , 2000. Trabalhos de detalhe, realizados no âmbito do substrato siálico arqueano (e. g. Machado Filho et al, 1983;Teixeira et al, 1998Teixeira et al, , 2000 têm revelado uma vasta gama de litotipos, aqui agrupados no Complexo Metamórfico Campo Belo (CMCB), cuja história evolutiva remonta ao Mesoarqueano (e. g. Campos et al, 2003;Carneiro et al, 1996aCarneiro et al, , 1996bCarneiro et al, , 1997aCarneiro et al, , 1997bCarneiro et al, , 1997cCarvalho Júnior, 2001;Carvalho Júnior et al, 1997;Corrêa da Costa, 1999;Fernandes, 2001;Oliveira, 1999;Oliveira e Carneiro, 2001;Oliveira, 2004;Teixeira et al, 1996Teixeira et al, , 1998Teixeira et al, , 2000.…”