Petrology of ultramafic xenoliths in Cenozoic alkaline rocks of northern Madagascar (Nosy Be Archipelago)

Rocco, Ivana; Lustrino, Michele; Zanetti, A.; Morra, Vincenzo; Melluso, Leone

doi:10.1016/j.jsames.2012.06.012

Cited by 15 publications

(3 citation statements)

References 59 publications

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“…E: Lee et al (1996), Caldeira and Munhá (2002), Nkouandou andTemdjim (2011), Temdjim (2012), Pintér et al (2015); filled symbols: continental Cameroon Line; empty symbols: oceanic Cameroon Line. F: Rocco et al (2013) mostly spinel peridotites ( Fig. 4C; Furnes et al 1986;Ionov et al 2002).…”

Section: Other European Xenolith Localitiesmentioning

confidence: 96%

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The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths

Embey-Isztin

2016

Central European Geology

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Mantle peridotites are interpreted as either residues after partial melting and melt extraction or products of igneous refertilization of refractory peridotites. The simple distinction between these models is difficult to assess because in chemical variation diagrams, both processes lead essentially to the same results. The only exception is the Ti-in-Cpx versus Ti-in-whole-rock plots, which can successfully discriminate between these models. In this study, a modified version of Ti-in-Cpx versus Mg#-in-olivine plots was applied to ∼1,500 spinel peridotite xenoliths from worldwide localities. The results showed that the vast majority of shallow mantle samples are consistent with the partial melting model; however, a minority of samples may indicate refertilization of formerly refractory mantle domains.

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Section: Other European Xenolith Localitiesmentioning

confidence: 96%

“…The northwestern region of Madagascar is covered by basanitic volcanics of late Cenozoic age and the Nosy Be archipelago is the northwestern most part of this igneous activity, where peridotite xenoliths are common (Rocco et al 2013; Fig. 4F).…”

Section: African Xenolithsmentioning

confidence: 99%

The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths

Embey-Isztin

2016

Central European Geology

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“…Spongy cpx textures have been reported in SCLM xenoliths from many locations around the world (e.g., Ionov et al, 1995Ionov et al, , 2006Wiechert et al, 1997;Bonadiman et al, 2005;Liu et al 2017;Rocco et al, 2013Rocco et al, , 2017. The origin of these textures has been attributed to either metasomatic reactions (Shaw et al, 2006;Rocco et al, 2013) or decompressional partial melting (Su et al, 2011).…”

Section: Origin Of the Spongy Cpx Texturementioning

confidence: 99%

Petrology and geochemistry of the Tasse mantle xenoliths of the Canadian Cordillera: A record of Archean to Quaternary mantle growth, metasomatism, removal, and melting

et al. 2018

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Mantle xenoliths hosted by the Quaternary Tasse alkaline basalts in the Canadian Cordillera, southeastern British Columbia, are mostly spinel lherzolite originating from subcontinental lithospheric mantle. The xenoliths contain abundant feldspar veins, melt pockets and spongy clinopyroxene, recording extensive alkaline metasomatism and partial melting. Feldspar occurs as veins and interstitial crystal in melt pockets. Melt pockets occur mainly at triple junctions, along grain boundaries, and consist mainly of olivine, cpx, opx and spinel surrounded by interstitial feldspar. The Nd, Sr and Pb isotopic compositions of the xenoliths indicate that their sources are characterized by variable mixtures of depleted MORB mantle and EM1 and EM2 mantle components. Large variations in eNd values (-8.2 to +9.6) and Nd depleted mantle model ages (TDM = 66 to 3380 Ma) are consistent with multiple sources and melt extraction events, and long-term (>3300 Ma) isolation of some source regions from the convecting mantle. Samples with Archean and Paleoproterozoic Nd model ages are interpreted as either have been derived from relict Laurentian mantle pieces beneath the Cordillera or have been eroded from the root of the Laurentian craton to the east and transported to the base of the Cordilleran lithosphere by edge-driven convection currents. The oxygen isotope compositions of the xenoliths (average d 18 O = +5.1±0.5‰) are similar to those of depleted mantle. The average d 18 O values of olivine (+5.0±0.2‰), opx (+5.9±0.6‰), cpx (+6.0±0.6‰) and spinel (+4.5±0.2‰) are similar to mantle values. Large fractionations for olivine-opx, olivine-cpx and opx-cpx pairs, however, reflect disequilibrium stemming from metasomatism and partial melting. Whole-rock trace element, Nd, Sr, Pb and O isotope compositions of the xenoliths and host alkaline basalts indicate different mantle sources for these two suites of rocks. The xenoliths were derived from shallow lithospheric sources, whereas the alkaline basalts originated from a deeper asthenospheric mantle source.

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The age and petrogenesis of alkaline magmatism in the Ampasindava Peninsula and Nosy Be archipelago, northern Madagascar

Cucciniello

Tucker²,

Jourdan

et al. 2015

Miner Petrol

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The Ampasindava alkaline province consists of a series of circular and elliptical intrusions, lava flows, dyke swarms and plugs of Cenozoic age emplaced into the Mesozoic-Cenozoic sedimentary rocks of the Antsiranana basin (NW Madagascar) and above the crystalline basement. The magmatism in the Ampasindava region is linked to a NW-SE trending extensional tectonic setting. New 40Ar/39Ar age determinations on feldspar separate of alkali granites and basaltic dykes yielded ages of 18.01 ± 0.36 Ma and 26 ± 7 Ma, respectively. Alkali basalts and basanites, nepheline syenites and phonolites, and silica saturated-to-oversaturated syenites, trachytes, granites and rhyolites are the main outcropping lithologies. These rocks have sodic affinity. The felsic rocks are dominant, and range from peraluminous to peralkaline. The mantle-normalized incompatible element patterns of the mafic lavas match those of Na-alkaline lavas in within-plate rift settings. The patterns are identical in shape and absolute concentrations to those of the Bobaomby (Cap d’Ambre) and Massif d’Ambre primitive volcanic rocks. These geochemical features are broadly compatible with variable degrees of partial melting of incompatible element-enriched mantle sources. The mineralogical and geochemical variations are consistent with fractional crystallization processes involving removal of olivine, feldspar, clinopyroxene, amphibole, Fe-Ti oxides and apatite. Removal of small amount of titanite explains the concave upward lanthanide pattern in the evolved nepheline syenites and phonolites, which are additionally rich in exotic silicates typical of agpaitic magmas (eudialyte, F-disilicates)

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Petrology of ultramafic xenoliths in Cenozoic alkaline rocks of northern Madagascar (Nosy Be Archipelago)

Cited by 15 publications

References 59 publications

The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths

The role of melt depletion versus refertilization in the major element chemistry of four-phase spinel peridotite xenoliths

Petrology and geochemistry of the Tasse mantle xenoliths of the Canadian Cordillera: A record of Archean to Quaternary mantle growth, metasomatism, removal, and melting

The age and petrogenesis of alkaline magmatism in the Ampasindava Peninsula and Nosy Be archipelago, northern Madagascar

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