Tectonic boundaries, crustal weakness zones and plume-subcontinental lithospheric mantle interactions in the Serra do Mar dyke swarm, SE Brazil

Valente, Sérgio de Castro; Corval, Artur; Duarte, Beatriz Paschoal; Ellam, Robert M.; Fallick, Anthony E.; Meighan, I. G.; Dutra, Thiago

doi:10.25249/0375-7536.2007371194201

Cited by 33 publications

(32 citation statements)

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“…The main strike direction is NE-SW, coincident with that of the magmatic bodies previously mentioned, with a secondary NW-SE system mainly observed at the Buzios region, where it shows cross-cutting relationships with the dykes, indicating both previous activity and reactivation during the rifting phase. Valente et al (2007) showed that two distinct suites of dykes occur: a low-Ti diabase system, that intrudes only the CFTD, and a high-Ti diabase system that intrude the rest of the Ribeira Orogen. The authors propose that it could be either related to the different nature of the lithospheric mantle underneath the CFTD or to differential litho spheric thickness prior to rifting.…”

Section: Tectonic Evolution During the Meso-cenozoicmentioning

confidence: 99%

“…130 Ma in this region and generation of the South Atlantic lithosphere. This age is represented by mafic dykes, basin formation, flood basalts and alkaline intrusions (Valente et al 2007;Geraldes et al 2013). …”

Section: Geochronological Barcode Of the Cabo Frio Tectonic Domainmentioning

confidence: 99%

“…However, it may have potentially facilitated the melting concentration and/or migration towards the region of thinner crust under the CFTD. The existence of regions of crustal weakness acting as conduits for the magmatism has been proposed by Valente et al (2007) to explain the differing geochemical signatures observed for the low Ti mafic dykes along the CFTD. This is coherent with the presence of magmatic bodies sources for the observed magnetic and gravity highs onshore and offshore the CFTD (Stanton et al 2010).…”

Section: The Third Continental Marginmentioning

confidence: 99%

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The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: a Paleoproterozoic through Cretaceous saga of a reworked continental margin

et al. 2016

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ABSTRACT:The Cabo Frio Tectonic Domain is composed of a Paleoproterozoic basement tectonically interleaved with Neoproterozoic supracrustal rocks (Buzios-Palmital successions). It is in contact with the Neoproterozoic-Cambrian Ribeira Orogen along the SE Brazilian coast. The basement was part of at least three continental margins: (a) 1.97 Ga; (b) 0.59 -0.53 Ga; (c) 0.14 Ga to today. It consists of continental magmatic arc rocks of 1.99 to 1.94 Ga. Zircon cores show a 2.5 -2.6 Ga inheritance from the ancient margin of the Congo Craton. During the Ediacaran, this domain was thinned and intruded by tholeiitic mafic dykes during the development of an oceanic basin at ca. 0.59 Ma. After the tectonic inversion, these basin deposits reached high P-T metamorphic conditions, by subduction of the oceanic lithosphere, and were later exhumed as nappes over the basement. The Cabo Frio Tectonic Domain collided with the arc domain of the Ribeira Orogen at ca. 0.54 Ga. It is not an exotic block, but the eastern transition between this orogen and the Congo Craton. Almost 400 m.y. later, the South Atlantic rift zone followed roughly this suture, not coincidently. It shows how the Cabo Frio Tectonic Domain was reactivated as a continental margin in successive extensional and convergent events through geological time.KEYWORDS: Ribeira Orogen; sutures; Orosirian; Cambrian; South Atlantic. RESUMO: O Domínio Tectônico do Cabo Frio é formado essencialmente por um embasamento paleoproterozoico tectonicamente intercalado com rochas supracrustais do Neoproterozoico (Sucessões Buzios e Palmital). Está em contato com o orógeno neoproterozoico-cambriano Ribeira na costa SE do Brazil. O embasamento já fez parte de pelo menos três margens continentais: (a) a 1,97 Ga

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Section: Tectonic Evolution During the Meso-cenozoicmentioning

confidence: 99%

Section: Geochronological Barcode Of the Cabo Frio Tectonic Domainmentioning

confidence: 99%

Section: The Third Continental Marginmentioning

confidence: 99%

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The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: a Paleoproterozoic through Cretaceous saga of a reworked continental margin

et al. 2016

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“…According to some interpretations, PCFB tholeiites would reflect the participation of the Tristan da Cunha plume (Gibson et al1999;Milner & le Roex 1996;Ewart et al 2004;Valente et al 2007), which may have contributed as a source of heat and material to the magmatism. In contrast, an origin from partial melting of heterogeneous SCLM has been proposed, taking into account the elemental and Sr-Nd-Pb isotope characteristics of PCFB tholeiites (Peate 1997;Peate et al 1999;Marques et al 1999 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Lead isotope constraints on the mantle sources involved in the genesis of Mesozoic high-Ti tholeiite dykes (Urubici type) from the São Francisco Craton (Southern Espinhaço, Brazil)

et al. 2016

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ABSTRACT:The first results of Pb isotope compositions of the high-Ti Mesozoic dykes of the Southern Espinhaço are presented. The results do not show large variations and are significantly more radiogenic than the Pb isotope compositions of the high-Ti tholeiites from the Paraná Continental Flood Basalts. The data combined with published geochemical and Sr-Nd isotope results rule out crustal contamination processes in the genesis of the dykes, requiring magma generation in metasomatized subcontinental lithospheric mantle with the involvement of HIMU-type and carbonatite components. The magmas may have been also derived from a mantle source containing ~4 -5% of pyroxenite and ~1% of carbonatite melts, agreeing with published Os isotope compositions of high-Ti rocks from the Paraná Continental Flood Basalts. These metasomatizing agents could be responsible for mantle source refertilization, as was also proposed in the literature to explain the characteristics of xenoliths of the Goiás Alkaline Province, which also occurs in the border of the São Francisco Craton. Additionally, to evaluate the risks of Pb contamination during sample preparation for analysis, several experimental tests were accomplished, which indicate the need of sawed surface removal and a careful washing of small-sized rock fragments before powdering, especially for rocks with [Pb] < 7 μg/g.

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“…Subvertical diabase dikes oriented N45-60E with thicknesses varying from <1 to ∼10 m appear in several localities of Ilha Anchieta, and are related to the Serra do Mar Dike Swarm of the Cretaceous (∼140-134 Ma) Paraná-Etendeka Large Igneous Province (Valente et al 2007). An interesting feature associated with one of these tholeiitic dikes crops out at the western portion of Ilha Anchieta: a magmatic breccia produced by the interaction between the basaltic magma and the enclosing foliated charnockites/granites.…”

Section: Local Geologymentioning

confidence: 99%

The Ilha Anchieta Quartz Monzonite: the southernmost expression of ca. 500 Ma post-collisional magmatism in the Ribeira Belt

Sobrinho

Janasi

Simonetti

et al. 2011

An. Acad. Bras. Ciênc.

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The Ilha Anchieta Quartz Monzonite (IAQM) occupies most of the homonymous island in the coast of the state of São Paulo, and is intrusive into foliated rocks of the ∼565 Ma Ubatuba Charnockite. The main petrographic variety is a porphyritic biotite-hornblende quartz monzonite with 2-4 cm tabular microcline megacrysts set in a medium-grained groundmass and magmatic foliation. Outcrop-scale structures indicate cumulative processes (modal and grain-size magmatic banding) and interaction with basic magmas (mafic microgranular enclaves). Lithogeochemical data indicates that the main variety is intermediate to acid (SiO 2 = 63-67%), alkali-calcic, metaluminous and magnesian (mg# ∼30), showing moderate Sr (300-400 ppm) and Ba (∼1500 ppm) contents and relatively high HFSE (Nb = 40 ppm; Zr = 550-700 ppm). The older charnockites are more silicic (SiO 2 = 71-78%), ferroan (mg# = 12-16), and have very low Sr (13-80 ppm) contents, resulting in Ba/Sr ratios remarkably higher than the IAQM (10 versus 4). LA-MC-ICPMS U-Pb zircon dating of the IAQM yielded 499.7 ± 5.9 Ma. This is the youngest magmatic age identified so far in the crystalline basement of the state of São Paulo, and indicates that the pluton is the southernmost expression of the post-collisional "G5" magmatism in the Ribeira Belt.

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Tectonic boundaries, crustal weakness zones and plume-subcontinental lithospheric mantle interactions in the Serra do Mar dyke swarm, SE Brazil

Cited by 33 publications

References 0 publications

The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: a Paleoproterozoic through Cretaceous saga of a reworked continental margin

The tectonic significance of the Cabo Frio Tectonic Domain in the SE Brazilian margin: a Paleoproterozoic through Cretaceous saga of a reworked continental margin

Lead isotope constraints on the mantle sources involved in the genesis of Mesozoic high-Ti tholeiite dykes (Urubici type) from the São Francisco Craton (Southern Espinhaço, Brazil)

The Ilha Anchieta Quartz Monzonite: the southernmost expression of ca. 500 Ma post-collisional magmatism in the Ribeira Belt

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