Lunar initial 143Nd/144Nd: Differential evolution of the lunar crust and mantle

Lugmair, G. W.; Marti, K.

doi:10.1016/0012-821x(78)90021-3

Cited by 990 publications

(263 citation statements)

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“…Nd-isotopic ratios were corrected for mass fractionation by normalizing to 146 Nd/ 144 Nd = 0.7219. The decay constant used was 6.54 x 10 -12 year -1 (Lugmair & Marti 1978). Model ages were calculated according to the depleted mantle curve through time by De Paolo (1981).…”

Section: Methodsmentioning

confidence: 99%

Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

et al. 2015

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ABSTRACT:The Taquaral Granite is located on southern Amazon Craton in the region of Corumbá, westernmost part of the Brazilian state of Mato Grosso do Sul (MS), near Brazil-Bolivia frontier. This intrusion of batholitic dimensions is partially covered by sedimentary rocks of the Urucum, Tamengo Bocaina and Pantanal formations and Alluvial Deposits. The rock types are classified as quartz-monzodiorites, granodiorites, quartz-monzonites, monzo and syenogranites. There are two groups of enclaves genetically and compositionally different: one corresponds to mafic xenoliths and the second is identified as felsic microgranular enclave. Two deformation phases are observed: one ductile (F 1 ) and the other brittle (F 2 ). Geochemical data indicate intermediate to acidic composition for these rocks and a medium to high-K, metaluminous to peraluminous calk-alkaline magmatism, suggesting also their emplacement into magmatic arc settings. SHRIMP zircon U-Pb geochronological data of these granites reveals a crystallization age of 1861 ± 5.3 Ma. Whole rock Sm-Nd analyses provided ε Nd(1,86 Ga) values of -1.48 and -1.28 and T DM model ages of 2.32 and 2.25 Ga, likely indicating a Ryacian crustal source. Here we conclude that Taquaral Granite represents a magmatic episode generated at the end of the Orosirian, as a part of the Amoguija Magmatic Arc.

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Section: Methodsmentioning

confidence: 99%

Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

et al. 2015

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“…The NBS 987 reference material yielded a long-time average Hanžl et al (2007). 87 Sr Steiger and Jäger (1977) (Sr) and Lugmair and Marti (1978) …”

Section: Methodsmentioning

confidence: 99%

The Early Cretaceous volcanic activity in the western part of the Gobi-Altay rift (Shiliin Nuruu, SW Mongolia)

Buriánek¹,

Hanžl²,

Erban³

et al. 2012

J. Geosci.

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The Cretaceous continental sedimentation in SW Mongolia was commonly accompanied by volcanic activity. Bimodal association of the Cretaceous Khulsan Gol Formation is represented mostly by calc-alkaline and rare alkaline volcanic rocks (basaltic andesite, trachybasalt to trachyandesite lavas or tuffs with lahars). The lavas were extruded mainly subaerially, although locally there is a subaqueous component present corresponding to final phases of Mesozoic sedimentation in the Gobi-Altay rift zone. Variations in chemical and isotopic composition reflect crustal assimilation coupled with fractional crystallization of parental magma generated by melting of lower lithosphere and/or uppermost asthenospheric mantle. These within-plate volcanic rocks can be explained as initial stages of Cenozoic magmatic activity in the Mongolia.

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“…The accuracy and reproducibility of results were controlled by standards using BCR-1 [( 143 Nd/ 144 Nd ranged from 0.512573 ± 12 (2σ) to 0.512669 ± 10 (2σ)], with the average value of 0.512622 ± 28 (2σ)) and La Jolla ( 143 Nd/ 144 Nd isotopic ratios ranged from 0.511793 ± 9 to 0.511883 ± 5, with most values being above 0.5118) (Oliveira et al 2008). The decay constant used was 6.54 × 10 -12 a -1 (Lugmair & Marti 1978), and the Nd model ages (TDM) were calculated according to the model of depleted mantle evolution of DePaolo (1981). During the period of Sm and Nd procedures, total chemical blanks were lower than 0.1% of the elements concentration and were considered negligible.…”

Section: Sm-nd Isotopic Analysesmentioning

confidence: 98%

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

et al. 2017

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ABSTRACT:The São Luís Cráton comprises an area between northeast Pará state and northwest Maranhão that exposes Paleoproterozoic granitic suites and meta-volcanosedimentary sequences. In the east of this geotectonic unit, about 70 km south of São Luís, there is a portion of the São Luís Craton, represented by the intrusive Rosario Suite (RS). This work is focused on rocks of this suite, including petrographic, lithochemical and geochronological studies to understand the crustal evolution of these granitoid rocks. The rock spectrum varies from tonalitic to granodioritic, quartz dioritic and granitic compositions, and there are partial structural and mineralogical changes related to deformation along transcurrent shear zones. The geochemical studies show granitic metaluminous compositions of the calc-alkaline series with I-type affinity typical of magmatic arc. Rare earth elements show marked fractionation and slight Eu positive or negative anomalies (Eu/Eu* = 0.82 to 1.1). Zircon U-Pb data provided consistent ages of 2165 ± 7 Ma, 2170 ± 7 Ma, 2170 ± 7 Ma, 2161 ± 4 Ma and 2175 ± 8 Ma, dating emplacement of these granitoids as Paleoproterozoic (Rhyacian). Sm-Nd isotopic data provided model ages (T DM ) of 2.21 to 2.31 Ga with positive values of εNd +1.9 to +3.2 (t = 2.17 Ga), indicating predominantly Rhyacian crustal sources for the parental magmas, similar to those ones found in other areas of the São Luís Craton. The data, integrated with published geological and geochronological information, indicate the occurrence of an important continental crust formation event in this area. The Paleoproterozoic evolution between 2.17 and 2.15 Ga is related to the Transamazonian orogeny. The granitoids of the Rosario Suite represent the main phase of continental arc magmatism that has continuity in other parts of the São Luís Craton and can be correlated with Rhyacian accretionary magmatism in the northwestern portion of the Amazonian Craton that amalgamated Archean terrains during the Transamazonian orogeny.KEYWORDS: Rosário Suite; São Luís Craton; Petrology; U-Pb geochronology; Sm-Nd T DM . RESUMO: O Cráton INTRODUCTIONIn models of global supercontinent reconstruction, the São Luís Craton and the northeastern portion of the Amazonian Craton (to the east of the Guayana Shield) have been considered remnants of the West African Craton preserved in the northern South American Platform after the breakup of the Pangea Supercontinent (Hurley et al. 1967, Torquato & Cordani 1981, Lesquer et al. 1984, Brito Neves et al. 2000.On the African side, several studies based on structural, geochemical, geophysical and geochronological data demonstrate the existence of Archean and dominantly juvenile Paleoproterozoic crust (Abouchami et al. 1990, Boher et al. 1992, Gasquet et al. 2003. On the Brazilian side, the northern part of the Amazonian Craton and São Luís Craton have demonstrated geochronological and evolutionary similarities. In this part of the Amazonian Craton, the ancient continental crust stabilized in the Archean is bordered by...

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Lunar initial 143Nd/144Nd: Differential evolution of the lunar crust and mantle

Cited by 990 publications

References 10 publications

Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

The Early Cretaceous volcanic activity in the western part of the Gobi-Altay rift (Shiliin Nuruu, SW Mongolia)

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

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