30 million years of Permian volcanism recorded in the Choiyoi igneous province (W Argentina) and their source for younger ash fall deposits in the Paraná Basin: SHRIMP U–Pb zircon geochronology evidence

Rocha-Campos, A. C.; Basei, Miguel Ângelo Stipp; Nutman, Allen P.; Kleiman, Laura Elena; Varela, Ricardo; Llambías, Eduardo Jorge; Canile, Fernanda Maciel; Rosa, O. de C.R. da

doi:10.1016/j.gr.2010.07.003

Cited by 192 publications

(108 citation statements)

References 36 publications

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“…The Beaufort Group records the transition to terrestrial deposystems and evolution of terrestrial vertebrates and macroflora (Groenewald and Kitching 1995;Smith 1995;Gastaldo et al 2005). Interbedded throughout the Ecca and Beaufort strata are numerous air-fall volcanic tuffs thought to have been produced by a late Palaeozoic Gondwanan magmatic arc, the remnants of which are locally preserved as the Choiyoi and Puesto Viejo magmatic suites in South America (Veevers et al 1994a;López-Gamundí 2006;Kleiman and Japas 2009;Rocha-Campos et al 2011;López-Gamundí et al 2013). Choiyoi and Puesto Viejo magmatism dates from~276 to~234 Ma and is responsible for air-fall ash deposits in the Paraná (Rocha-Campos et al (Spalletti et al 2008) in South America, in addition to the Karoo Basin in South Africa ( Figure 1B), based on palaeogeography and geochemistry (López-Gamundi et al 2006).…”

Section: Geologic Backgroundmentioning

confidence: 99%

U-PB zircon tuff geochronology from the Karoo Basin, South Africa: implications of zircon recycling on stratigraphic age controls

McKay

Weislogel

Fildani³

et al. 2015

International Geology Review

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Along the >650 km long southern margin of the Karoo Basin in South Africa, we traversed four evenly spaced stratigraphic transects and collected 22 samples of volcanic, air-fall tuffs thought to be distal deposits derived from the Permian-Triassic Southern Gondwanan volcanic arc. We present 469 new U-Pb zircon ages determined by sensitive high-resolution ion microprobe reverse geometry (SHRIMP-RG) at the Stanford-USGS Microanalytical Center in order to constrain the maximum depositional ages for the southern Karoo Basin strata. Weighted means of these youngest coherent zircon populations were selected to maximize the number of analyses while minimizing the mean square weighted deviation (MSWD) to increase the robustness and decrease the influence of Pb-loss and inheritance in determining the maximum depositional age. Maximum depositional ages for the marine Ecca Group range from 250 to 274 Ma, whereas in the conformably overlying terrestrial Beaufort Group maximum depositional ages ranged from 257 to 452 Ma. Across the southern Karoo Basin, the Ecca Group tuffs produce maximum depositional ages that young upward; however, the Beaufort Group tuffs yield maximum depositional ages that are geochronologically out of sequence. Furthermore, maximum depositional ages of the Beaufort Group tuffs are consistently older than ash ages within the underlying marine strata. Our results are supported by previously published U-Pb tuff zircon geochronology in the Karoo Basin and demonstrate that the presence of out-of-sequence, older tuff ages are repeatable in Beaufort Group tuffs along the southern margin of the basin. We propose that tuffs in the Karoo Basin are correlative with tuffs in southern South America, and that the age spectra of these tuffs were influenced by magmatic crustal recycling. We use these data to highlight the complexity of U-Pb zircon datasets from tuffs, address the use of U-Pb zircon ages to provide absolute age controls, and discuss the implications of these new age controls on the Permian-Triassic Karoo strata.

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Section: Geologic Backgroundmentioning

confidence: 99%

U-PB zircon tuff geochronology from the Karoo Basin, South Africa: implications of zircon recycling on stratigraphic age controls

McKay

Weislogel

Fildani³

et al. 2015

International Geology Review

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“…2; 268,8 a 259,9 Ma; Daemon & Quadros 1970;Barberena et al 1985;Lages 2004;López-Gamundí 2006;Santos et al 2006;Rocha-Campos et al 2011).…”

Section: Estratigrafia Da Formação Serra Altaunclassified

A Formação Serra Alta, Permiano, no centro-leste do Estado de São Paulo, Bacia do Paraná, Brasil

et al. 2015

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RESUMO:A individualização e o mapeamento da Formação Serra Alta no Estado de São Paulo sempre foi motivo de controvérsia na comunidade geológica. Apesar de apresentar extensão comparável à Formação Irati em subsuperfície, a unidade ainda carece de estudos mais acurados acerca de seu posicionamento estratigráfico, conteúdo fossilífero, sistema deposicional e idade. Na região centro-leste do Estado de São Paulo, a Formação Serra Alta sucede estratigraficamente a Formação Irati, sendo constituída por depósitos pelíticos cinza escuros. A unidade é mapeada desde o limite sul do estado até o Domo de Gibóia, no Município de Rio das Pedras. Neste local, as formações Serra Alta e Teresina são substituídas pelos depósitos pelíticos da Formação Corumbataí, que se estende para norte, além do limite do Estado de São Paulo, e pode ser considerada unidade correlata a estas. Neste estudo, são apresentadas seções colunares e caracterizados os contatos da Formação Serra Alta com as formações permianas verticalmente contíguas. É apresentada também detalhada análise de fácies, com a finalidade de caracterizar o sistema deposicional. A análise de perfis de sondagem possibilitou também melhor compreensão dos padrões arquiteturais da Formação Serra Alta, auxiliando na determinação de sua real distribuição e posição estratigráfica na porção centro-sul do estado. A integração das informações obtidas permitiu identificar tendências de empilhamento transgressivo particulares, contribuindo para o detalhamento da sucessão predominantemente regressiva em que se depositaram as unidades permianas da Bacia do Paraná. PALAVRAS-CHAVE:Formação Serra Alta; sedimentologia; estratigrafia; paleontologia; Permiano; Bacia do Paraná. ABSTRACT: The delimitation and mapping of the Serra Alta Formation in the São

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“…Japas (2009) andRocha Campos et al (2011) subdivided the Choiyoi magmatism in a lower section (with ages between 280 and 265 Ma) and an upper section (with ages between 265 and 250 Ma). Triassic volcanic sequences are separately grouped in a synrift phase.…”

Section: Discussionmentioning

confidence: 99%

“…Although, other authors have pointed out that an early stage the magmatism was related to subduction, followed by non orogenic magmatism related to active rifting (Kay et al, 1989;Mpodozis and Ramos, 1990;Llambías and Sato, 1990). Japas (2009) andRocha Campos et al (2011) consider that the 31°S to 36°S segment could be regarded as a transitional zone between different subduction segments after 270 Ma. The northern segment would be normal in dip angle and the southern shallower of that.…”

Section: Geological Settingmentioning

confidence: 99%

Geoquímica, dataciones U-Pb SHRIMP sobre circón e isótopos de Hf del magmatismo gondwánico en el NW de Argentina: petrogénesis e implicancias geodinámicas.

Poma

Zappettini

Quenardelle

et al. 2014

Andgeo

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ABSTRACT.We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations as well as geochemical analyses on three plutonic units of Gondwanan magmatism that crop out in NW Argentina. Two episodes of different age and genesis have been identified. The older one includes gabbros and diorites (Río Grande Unit) of 267±3 Ma and granitoids (belonging to the Llullaillaco Unit) of 263±1 Ma (late Permian, Guadalupian); the parent magmas were generated in an intraplate environment and derived from an enriched mantle but were subsequently contaminated by crustal components. The younger rocks are granodiorites with arc signature (Chuculaqui Unit) and an age of 247±2 Ma (middle Triassic-Anisian). Hf isotope signature of the units indicates mantle sources as well as crustal components. Hf model ages obtained are consistent with the presence of crustal Mesoproterozoic (mainly Ectasian to Calymnian (T DM(c) =1.24 to 1.44 Ga-negative Hf (T) ) and juvenile Cryogenian sources (T DM =0.65 to 0.79 Ga-positive ɛ Hf (T) ), supporting the idea of a continuous, mostly Mesoproterozoic, basement under the Central Andes, as an extension of the ArequipaAntofalla massif. The tectonic setting and age of the Gondwanan magmatism in NW Argentina allow to differentiate: a. Permian intra-plate magmatism developed under similar conditions to the upper section of the Choiyoi magmatism exposed in the Frontal Cordillera and San Rafael Block, Argentina; b. Triassic magmatism belonging to a poorly known subduction-related magmatic arc segment of mostly NS trend with evidence of porphyry type mineralization in Chile, allowing to extend this metallotect into Argentina.

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30 million years of Permian volcanism recorded in the Choiyoi igneous province (W Argentina) and their source for younger ash fall deposits in the Paraná Basin: SHRIMP U–Pb zircon geochronology evidence

Cited by 192 publications

References 36 publications

U-PB zircon tuff geochronology from the Karoo Basin, South Africa: implications of zircon recycling on stratigraphic age controls

U-PB zircon tuff geochronology from the Karoo Basin, South Africa: implications of zircon recycling on stratigraphic age controls

A Formação Serra Alta, Permiano, no centro-leste do Estado de São Paulo, Bacia do Paraná, Brasil

Geoquímica, dataciones U-Pb SHRIMP sobre circón e isótopos de Hf del magmatismo gondwánico en el NW de Argentina: petrogénesis e implicancias geodinámicas.

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