The Petrogenesis of the Niquelandia Layered Basic-Ultrabasic Complex, Central Goias, Brazil

Girardi, Vicente Antônio Vitório; Rivalenti, Giorgio; Sinigoi, S.

doi:10.1093/petrology/27.3.715

Cited by 41 publications

(68 citation statements)

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“…Based on SHRIMP U-Pb zircon ages and a SmNd internal isochrons, these authors attributed to LC and UC crystallization ages of 797±10 Ma and to 1248±23 Ma respectively. However, according to Girardi et al [6], Correia et al [9], Rivalenti et al [5] the two units belong to a single complex, with a gradational contact represented by the Hydrous Zone (HZ) and the differences between the two units are related to the different conditions of the same intrusion. This hypothesis was initially supported by SHRIMP U-Pb zircon ages obtained by Correia et al [9] from an anorthosite at the top of UC (sample Niq1552) which provided a crystallization age of 833±21 Ma.…”

Section: Discussionmentioning

confidence: 99%

“…According to Pimentel at al. [3], Ferreira Filho et al [17] and Moraes et al [18] the tholeiitic-MORB geochemical affinity [1][2][3][4][5][6] of the three complexes is consistent with a rift environment during the early stages of continental rifting up to the formation of an ocean basin.…”

Section: Geological Settingmentioning

confidence: 97%

“…the Goiás Massif). The Niquelândia mafic-ultramafic complex is relatively well-known [4][5][6][7][8][9][10], whereas the others two complexes of the Brasilia Belt (i.e. Cana Brava and Barro Alto) are still poorly studied.…”

Section: Introductionmentioning

confidence: 99%

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U-Pb zircon SHRIMP data from the Cana Bravalayered complex: new constraints for themafic-ultramafic intrusions of Northern Goiás,Brazil

et al. 2015

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Abstract:The Cana Brava Complex is the northernmost and least well known layered intrusion of a discontinuous belt of mafic-ultramafic massifs within the Brasilia Belt, which also comprises the Niquelândia and Barro Alto complexes. Available geochronological data from a range of techniques (K/Ar, Ar/Ar, Rb/Sr, Sm/Nd and U/Pb) provide a range of possible ages (time span from 3.9 Ga to 450 Ma), hence a precise and reliable age for the Cana Brava Complex is still lacking. Also, preliminary isotopic and geochemical data of the Cana Brava Complex suggest a significant crustal contamination, which could have affected bulk-rock Sr and Nd systematics resulting in meaningless age determinations. In this paper, we present new U-Pb SHRIMP zircon analyses from four samples of different units of the Cana Brava Complex which suggest that the intrusion occurred during the Neoproterozoic, between 800 and 780 Ma, i.e. at the same age of Niquelândia. Discordant older 206 Pb/ 238 U ages are provided by inherited zircons, and match the age of the metamorphism of the embedding Palmeirópolis Sequence.

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Section: Discussionmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 97%

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U-Pb zircon SHRIMP data from the Cana Bravalayered complex: new constraints for themafic-ultramafic intrusions of Northern Goiás,Brazil

et al. 2015

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“…Em alguns locais estas roc has apresenlam texturas porfiroclasticas onde restos de plagioclasio com granular;ao media entre 1,5 a 2,5 mm, encontram-se preservados na matriz fina, recristalizada, composta por plagioclasio e piroxenio, com granula(jOes variando entre 20 e 100 J.I.. Mesmo nos epidoto anfibolitos, ainda e possivel reconhecer antigos piroxenios igneos ago ra substituidos por anfib6lios de composi(jio tremolitica-actnolitica, e entre as concent ra ( Outros trabalhos como os de Bcswick (1982), Rollinson & Roberts (1986) e Pearce (1987), contribuíram para melhorar o conhecimento sobre os significados da existência ou não de correlações nestes diagramas e também para descriminar processos de alteração.…”

Section: Pelrografia O Complexo De Cana Bravaunclassified

Geoquímica e Petrologia das rochas máficas e ultramáficas do complexo estratiforme de Cana Brava-GO, e das suas encaixantes

Correia

Girardi

1998

Bol. IG-USP, Sér. cient.

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The Cana Brava body is a 2.0 Ga, anorogcnic, stratiform complex whose layers dip from 30" to ~"NW. The massif is made up of five units, composed of layers containing several associations of cumulus ph:oses :rnd variable amounts of inter-<::umulus minerals. Transitiorul betw~n units ;ore characteriud by changes in the composition and/or in the rebtive abundo.nce of tbese phases. Stratigraphically, the lowen sequence is ~omposed of amphibolites (PICBI), overlain by serpentinite. (PICB2), metawebsterites (PICB3) and metagabbroic rocks (PICB4 and PleB5) at tbe top. This sequence was originally formed by microgabbros, peridotites, websterites and gabbroic rocks.The rock sequence of the complex can be attributed to a ,ingle magmatic fractionation. Tbere is no evidence of multiple injections. Met amorphic events affe"ed tbe different units heterogeneously. The gabbroic rocks (pICB4 and PICBS) were the least tranuormed; hence their chemical compositions are close to tb e original ones. Units PICBI lU PICB) were tbe most affected by post-magmatic proces..,s.Geochemical evidences suggest tbat PICBt may be the chilled border of the massif.However, due to pon_magmatic phenomena, tbe compositioo of the parent magm a was calculated u.sing the chemiul compositions and inferred volumes of unils PICBl to PICBS. For PIeB2 and PICE3 the compositions of mineral phases were utiliud. Tbe possible Cana Brava parent magma is olivine-tholeiite, similar to tb e majority of tbe complexes utilized for compar;ron. In amount of normative olivine is within the range for liquids derived from 25 to 35% of mantle melting. Pbase equilibria can dictions point to pressures under 6-7 Kbar duringcrystallizo.tion.The possible parental magma of the Cana Brava complex is compared with tbe a1cali-olivine basaltic magma of the Palmeiropolis metavolcano.sedimentary sequence, and witb the possible parental magma of th e Serra da Bota satellite body. RESUMO

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“…Interlayers of high-degree metamorphic metasediments can be found as well as xenoliths in the mafic rocks. The available data suggest an anorogenic extensional environment for these intrusions (Girardi, et al, 1986, Feneira Filho et al, 1992) that was rifted apart from an uncertain continental plate. Wetl constrained U-Pb (SHRIMP) from Niquelândia (Correia et al, 1996) and a Sm-Nd isochron from Cana-Brava (Fugi, 1989) pointed the emplacement of these complexes at the Rhyacian/Orosirian boundary (2.0 Ga).…”

Section: -21 Statherian Taphrogeny: Attempts To Break-up Of the Sãmentioning

confidence: 96%

Extensão sul do sistema orogênico Tocantins no contexto geodinâmico da aglutinação do Gondwana: exercício de tectônica

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The Petrogenesis of the Niquelandia Layered Basic-Ultrabasic Complex, Central Goias, Brazil

Cited by 41 publications

References 0 publications

U-Pb zircon SHRIMP data from the Cana Bravalayered complex: new constraints for themafic-ultramafic intrusions of Northern Goiás,Brazil

U-Pb zircon SHRIMP data from the Cana Bravalayered complex: new constraints for themafic-ultramafic intrusions of Northern Goiás,Brazil

Geoquímica e Petrologia das rochas máficas e ultramáficas do complexo estratiforme de Cana Brava-GO, e das suas encaixantes

Extensão sul do sistema orogênico Tocantins no contexto geodinâmico da aglutinação do Gondwana: exercício de tectônica

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