Paleoproterozoic potassic–ultrapotassic magmatism: Morro do Afonso Syenite Pluton, Bahia, Brazil

Rios, Débora Correia; Conceição, Herbet; Davis, Donald W.; Cid, Jorge Plá; Rosa, Maria Lourdes Silva; Macambira, Moacir José Buenano; McReath, Ian; Marinho, Moacyr Moura; Davis, W J

doi:10.1016/j.precamres.2006.11.015

Cited by 45 publications

(45 citation statements)

References 77 publications

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“…Three models are commonly invoked to explain the genesis of alkaline igneous rocks: (1) crustal contamination of mantle-derived melt (e.g., Zhao et al, 1995;Wickham et al, 1996;Panter et al, 1997;Aydin et al, 2008;Yang et al, 2008); (2) fractional crystallization of mantle-derived alkali magmas (e.g., Panter et al, 1997;Weis et al, 1998;Battistini et al, 1998;Yang et al, 2005;Holbig and Grove, 2008); and (3) the partial melting of an enriched lithospheric mantle (e.g., Turner et al, 1996;Miller et al, 1999;Williams et al, 2004;Rios et al, 2007;Peng et al, 2008;Zhao et al, 2009aZhao et al, , 2009bHuang et al, 2010 (Fig. 10), and extreme enrichment in LILEs (e.g., Rb, Ba, and Sr) with negative Ta, Nb, and Ti anomalies (Fig.…”

Section: Genesis Of Cenozoic Mg-rich Potassic Rocks In Tibetmentioning

confidence: 99%

Cenozoic Mg-rich potassic rocks in the Tibetan Plateau: Geochemical variations, heterogeneity of subcontinental lithospheric mantle and tectonic implications

Chen

Wang

et al. 2012

Journal of Asian Earth Sciences

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Section: Genesis Of Cenozoic Mg-rich Potassic Rocks In Tibetmentioning

confidence: 99%

Cenozoic Mg-rich potassic rocks in the Tibetan Plateau: Geochemical variations, heterogeneity of subcontinental lithospheric mantle and tectonic implications

Chen

Wang

et al. 2012

Journal of Asian Earth Sciences

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“…The age of the beginning of the sedimentation remains undetermined, but we believe that it is not older than 1.8 Ga because rifts typically record relatively short periods of subsidence (e.g., Sengör, 1995). The Rhyacian source may originate from sin-to post-orogenic granites that are related to the orogenic activities along the belts, which sutured the several crustal blocks that constituted a large paleocontinent, including the Congo and São Francisco domains (for example, Rosa et al, 2000;Conceição et al, 2002Conceição et al, , 2003Conceição et al, , 2007Paim et al, 2002;Rios et al, 2007). The Archean sources are found in the Gavião block (e.g., Nutman and Cordani, 1992;Mougeot, 1996;Pinto et al, 1998;Rosa et al, 2000;Teixeira et al, 2000;Sabaté, 2002, 2004;Lana et al, 2013), which constitutes the main basement of the studied region.…”

Section: Origin and Age Of Riftingmentioning

confidence: 99%

Constraints on the Statherian evolution of the intraplate rifting in a Paleo-Mesoproterozoic paleocontinent: New stratigraphic and geochronology record from the eastern São Francisco craton

et al. 2015

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An integrated approach of stratigraphic analysis and U-Pb age dating reveals some information on the tectonosedimentary evolution of the Statherian cover of the São Francisco craton in the so-called Espinhaço basin (Atlantic shield in eastern Brazil). Here, continental sedimentation patterns, such as alluvial fan, braided-plain and lacustrine facies associations, with associated volcanic rocks are documented in two superposed basin fill-successions, which are defined as the Algodão and Sapiranga Synthems and grouped in the Botuporã Supersynthem. Both studied units consist mainly of conglomerates and cross-bedded sandstones and minor amounts of mudstones, sedimentary breccias, volcanic lava beds and volcaniclastic rocks, which were deposited in a rift basin -the Botuporã rift -during two syn-rifting phases. The Algodão Synthem represents the first rifting phase. The basal synsedimentary conglomerates of this unit were deposited mainly by subaerial debris flows, most likely along and near a rift border fault. The framework of this rock consists of only crystalline rock clasts from the basement and no fragments of volcanic rocks. Detrital zircon grains that were extracted from this facies show ages older than 2.05 Ga. The remainder of the section is dominated by fluvial sandy lithofacies with minor conglomerate lenses and sandstone-mudstone heterolithic lithofacies, which represent distal, waning-flood deposits in a lacustrine environment. The upper section also contains hummocky cross-stratified sandstone lithofacies, which are related to a storm-influenced deposition. On top of the Algodão succession, the volcanic rocks were dated at 1775 ± 7 Ma, which was interpreted as the near final age of the first rift-phase. Representing the second rift-phase, the Sapiranga Synthem shows similar sedimentation patterns to the Algodão Synthem. The Sapiranga Synthem rests directly on the volcanic rocks of the Algodão Synthem, and its basal conglomerates (which are most likely also related to a master fault) contain voluminous clasts of volcanic rocks, sandstones and crystalline rocks. The detrital zircon grains that were extracted from this facies show ages of 1741 ± 14 and 1766 Ma as well older than 2.05 Ga. The volcanic rocks on the upper succession of the Sapiranga Synthem record ages of 1740 ± 10 Ma, which finalized the Botuporã rift evolution. A preliminary geochemical study of volcanic rocks from the Botuporã Supersynthem showed that these rocks are alkaline rocks with high K 2 O/Na 2 O ratios, which belong to an ultrapotassic suite. The low concentrations of MgO wt.% suggest a felsic ultrapotassic character. The Botuporã Supersynthem is unconformably covered by a volcanosedimentary rift-succession of EoCalymmian age -the Pajeú Synthem, which represents the second rifting stage of the Espinhaço basin. Several Statherian-related volcano-sedimentary sequences and anorogenic granitoids occur dispersed in the São Francisco block, which requires a regional geologic model to explain the extensional and magmatism process during ...

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“…The later alkaline plutons, emplaced over the time span 2111e2070 Ma, are represented by syenites, monzonites, tonalites, granites and granodiorites, ranging from high-K calc-alkaline to shoshonite and ultrapotassic (Rios et al, 2007).…”

Section: Geological Settingmentioning

confidence: 99%

“…The plutonic activity at this time, in contrast to the early TTG and calcalkaline plutons, consists of relatively low silica granitoids with high-K 2 O contents and negative eNd(t) values emplaced along the greenstone belt-Archaean basement boundary. This K-rich magmatism is represented by ultrapotassic syenites (Conceição et al, 2002;Rios et al, 2007), lamprophyres (Plá Cid. et al, 2006), and shoshonitic to high-K calc-alkaline granitoids (Nascimento, 1996;Carvalho and Oliveira, 2003;Costa, 2008).…”

Section: Introductionmentioning

confidence: 99%

The Fazenda Gavião granodiorite and associated potassic plutons as evidence for Palaeoproterozoic arc-continent collision in the Rio Itapicuru greenstone belt, Brazil

Costa

Oliveira

McNaughton

2011

Journal of South American Earth Sciences

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Paleoproterozoic potassic–ultrapotassic magmatism: Morro do Afonso Syenite Pluton, Bahia, Brazil

Cited by 45 publications

References 77 publications

Cenozoic Mg-rich potassic rocks in the Tibetan Plateau: Geochemical variations, heterogeneity of subcontinental lithospheric mantle and tectonic implications

Cenozoic Mg-rich potassic rocks in the Tibetan Plateau: Geochemical variations, heterogeneity of subcontinental lithospheric mantle and tectonic implications

Constraints on the Statherian evolution of the intraplate rifting in a Paleo-Mesoproterozoic paleocontinent: New stratigraphic and geochronology record from the eastern São Francisco craton

The Fazenda Gavião granodiorite and associated potassic plutons as evidence for Palaeoproterozoic arc-continent collision in the Rio Itapicuru greenstone belt, Brazil

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