Migrating Cretaceous-Eocene Magmatismin the Serra do Mar Alkaline Province,SE Brazil: Melts from the Deflected Trindade Mantle Plume?

Thompson, Rhiannon

doi:10.1093/petrology/39.8.1493

Cited by 46 publications

(36 citation statements)

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“…1B), is, to some extent, similar to that of the Late Cretaceous kamafugites-glimmerites and carbonatites from APIP described by [6,7,40] for the following reasons: 1) an abundance of phlogopite, primary carbonates (aillikites, glimmerites, sÃÿvites and beforsites, after [41]) and olivine; and 2) compositions of diopside, phogopite (tetraferriphlogopite), carbonates, opaques (titanomagnetite and chromium-spinel) and accessory apatite, (Table 6). E and L, early and late crystallization, respectively.…”

Section: Significance Of the Mineralogysupporting

confidence: 62%

“…The following is a summary of the main points: 40 Ar/ 39 Ar (phlogopite and tetraferriphlogopite) yielded an age of approximately 600 Ma (averaging 602±16 Ma); and Rb/Sr systematics, relative to the MT-19 beforsite (whole rock, carbonate fraction and insoluble residue), define an isochron Rb/Sr of 598±10 Ma, similar to the Sm/Nd age (errorchron for all Figure 10. A) Incompatible elements normalized to primitive mantle concentrations (after [48]).…”

Section: Isotopic Systematicsmentioning

confidence: 86%

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Petrology of potassic alkaline ultramafic and carbonatitic rocks from Planalto da Serra (Mato Grosso State), Brazil

Comin-Chiaramontí¹,

Gomes²,

Min³

et al. 2014

Open Geosciences

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Abstract:The Planalto da Serra igneous rocks form plugs, necks and dykes of carbonate-rich ultramafic lamprophyres (aillikites and glimmerites with kamafugitic affinity) and carbonatites (alvikites and beforsites). Phlogopite and/or tetraphlogopite, diopside and melanitic garnet are restricted to aillikitic rock-types, whereas pyroclore occurs only in carbonatites. Aillikites and carbonatites are altered to hydrotermalites, having chlorite and serpentine as dominant minerals. Planalto da Serra igneous rock association has kamafugitic affinity (i.e. effusive, ultrapotassic. High LREE/HREE fractionation, incompatible elements data and Sr-Nd isotopes, suggest that the K-ultramafic alkaline and carbonatite rocks originated from a variably metasomatized mantle source enriched in radiogenic Sr. Crustal contamination is negligible or absent. Age values of 600 Ma rule out the geochronological relationship between the investigated intrusions and the Mesozoic alkaline bodies from the Azimuth 125 • lineament. The TDM model ages allow to conclude that Planalto da Serra magma is derived from the partial melting of a mantle source metasomatised by K-rich carbonatated melt during the Early to Late Neoproterozoic. On the basis of alkaline magmatism repetitions at 600 Ma and 90-80 Ma we question the subsistence of a stationary mantle plume for so long time. Keywords

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Section: Significance Of the Mineralogysupporting

confidence: 62%

Section: Isotopic Systematicsmentioning

confidence: 86%

Petrology of potassic alkaline ultramafic and carbonatitic rocks from Planalto da Serra (Mato Grosso State), Brazil

Comin-Chiaramontí¹,

Gomes²,

Min³

et al. 2014

Open Geosciences

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“…These enrichments, as indicated by isotopic data, could not be assigned to crustal contamination processes, but might be relate to the source region, in the mantle . A similar interpretation would seem to apply to all potassic mafic magmas of the Serra do Mar alkaline province (Thompson et al 1998, Brotzu et al 2005, Enrich et al 2005.…”

Section: Origin Of the Zr-and Ba-rich Minerals In The Ponte Nova Massifmentioning

confidence: 77%

Zr- AND Ba-RICH MINERALS FROM THE PONTE NOVA ALKALINE MAFIC-ULTRAMAFIC MASSIF, SOUTHEASTERN BRAZIL: INDICATION OF AN ENRICHED MANTLE SOURCE

Azzone

Ruberti

Enrich

et al. 2009

The Canadian Mineralogist

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Zirconium-and Ba-rich minerals are found in gabbroic rocks from the Ponte Nova alkaline mafic-ultramafic massif in southeastern Brazil. The unusual mineralogical assemblage includes zirconolite, baddeleyite, Ba-rich alkali feldspar, and Baand Ti-rich biotite. Zirconolite of the Ponte Nova massif has higher levels of Zr (up to 1.172 apfu) than those registered in other terrestrial rocks and a prominent enrichment in the light rare-earth elements. Baddeleyite contains small quantities of Hf, Ti, and Fe. The Ba-rich alkali feldspar and Ba-and Ti-rich biotite contain up to 9.25 and 7.35 wt% BaO, respectively, and the biotite contains up to 12.01 wt% TiO 2 . In the different intrusions of the Ponte Nova massif, such an unusual assemblage typifies the residual magma after the crystallization of clinopyroxene and olivine from previously enriched basanitic parental magma. The different trends of enrichments in REE and Th + U found for zirconolite of the intrusions of the Ponte Nova massif provide a better understanding of the variable degrees of enrichment of incompatible elements of the distinct gabbroic bodies. A lithospheric mantle source enriched in incompatible elements by the metasomatic action of volatile-rich fluids and with the presence of phlogopite or amphibole (or both) and other minor accessory phases could explain the presence of the Zr-and Ba-rich minerals in this gabbroic massif.

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“…Na margem atlântica brasileira sudeste, as idades AFT mais velhas foram obtidas no interior, com as idades mais jovens sendo progressivamente caracterizadas até a costa do continente com o Oceano Atlântico (GALLAGHER et al, 1994(GALLAGHER et al, , 1995HACKSPACHER et al, 2004;COGNÉ et al, 2011). O mais signifi cante evento de resfriamento/denudação ocorreu, após a abertura dos continentes e o magmatismo alcalino, entre 90 e 60 Ma (GALLAGHER et al, 1995;THOMPSON et al, 1998;RICCOMINI et al, 2005;COGNÉ et al, 2011), com os sedimentos continentais siliciclásticos depositados na Bacia Sedimentar de Santos Ar e (U-Th)/ He, respectivamente. Essa idade implica numa taxa de denudação de ~9 m Ma -1 desde então, com períodos de intenso intemperismo químico entre 17 e 9 Ma.…”

Section: Intemperismo Químicounclassified

Geoquímica Fluvial Aplicada À Avaliação Das Taxas De Intemperismo Químico E Remoção De Solo Da Formação Rio Claro

Couto¹,

Conceição

Fernandes³

et al. 2016

Rev. Bras. Geomorfol.

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Resumo:O objetivo deste trabalho foi determinar, pela geoquímica fl uvial, as taxas de intemperismo químico e remoção do solo na Formação Rio Claro, usando como área de estudo a bacia do Ribeirão Cachoeirinha, Rio Claro (SP). No exutório desta bacia hidrográfi ca foram analisados os seguintes parâmetros: vazão, sólidos totais dissolvidos (STD), sólidos totais em suspensão (STS), temperatura, pH, condutividade elétrica e oxigênio dissolvido. Os resultados revelaram um fl uxo anual de cátions e ânions de 114.3 t a -1 e uma taxa de intemperismo dos minerais silicáticos da Formação Rio Claro de 0.7 m Ma -1 , indicando uma baixa taxa Informações sobre o ArtigoRecebido (Received):

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Migrating Cretaceous-Eocene Magmatismin the Serra do Mar Alkaline Province,SE Brazil: Melts from the Deflected Trindade Mantle Plume?

Cited by 46 publications

References 0 publications

Petrology of potassic alkaline ultramafic and carbonatitic rocks from Planalto da Serra (Mato Grosso State), Brazil

Petrology of potassic alkaline ultramafic and carbonatitic rocks from Planalto da Serra (Mato Grosso State), Brazil

Zr- AND Ba-RICH MINERALS FROM THE PONTE NOVA ALKALINE MAFIC-ULTRAMAFIC MASSIF, SOUTHEASTERN BRAZIL: INDICATION OF AN ENRICHED MANTLE SOURCE

Geoquímica Fluvial Aplicada À Avaliação Das Taxas De Intemperismo Químico E Remoção De Solo Da Formação Rio Claro

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