The Petrology and Geochemistry of St. Helena Alkali Basalts: Evaluation of the Oceanic Crust-recycling Model for HIMU OIB

Kawabata, Hiroshi; Hanyu, Takeshi; Chang, Qing; Kimura, Jun–Ichi; Nichols, A. R.; Tatsumi, Yoshiyuki

doi:10.1093/petrology/egr003

Cited by 129 publications

(85 citation statements)

References 121 publications

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“…4 . The composition of these titanomagnetites overlaps data from most andesites, dacites and rhyolites 24 , as well as some basalts 25 . Most samples additionally contain a variable fraction of oxyexsolved titanomagnetites.…”

mentioning

confidence: 57%

Inferred time- and temperature-dependent cation ordering in natural titanomagnetites

et al. 2013

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Despite years of efforts to quantify cation distribution as a function of composition in the magnetite-ulvöspinel solid solution, important uncertainties remain about the dependence of cation ordering on temperature and cooling rate. Here we demonstrate that Curie temperature in a set of natural titanomagnetites (with some Mg and Al substitution) is strongly influenced by prior thermal history at temperatures just above or below Curie temperature. Annealing for 10 À 1 to 10 3 h at 350-400°C produces large and reversible changes in Curie temperature (up to 150°C). By ruling out oxidation/reduction and compositional unmixing, we infer that the variation in Curie temperature arises from cation reordering, and Mössbauer spectroscopy supports this interpretation. Curie temperature is therefore an inaccurate proxy for composition in many natural titanomagnetites, but the cation reordering process may provide a means of constraining thermal histories of titanomagnetite-bearing rocks. Further, our theoretical understanding of thermoremanence requires fundamental revision when Curie temperature is itself a function of thermal history.

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confidence: 57%

Inferred time- and temperature-dependent cation ordering in natural titanomagnetites

et al. 2013

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“…Sun and McDonough 1989;Kawabata et al 2011). It has been suggested (e.g., Melluso and Morra 2000;Cucciniello et al 2011b;Estrade et al 2014) that the mantle sources of the northern Madagascar magmatism bear hydrous phases, such as amphibole, in a way similar to the petrogenesis of mafic rocks in the nearby Comores archipelago (e.g., Class et al 1998).…”

Section: Discussionmentioning

confidence: 99%

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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“…Például a geokémiai vizsgá latok kimu tatták, hogy a Szent Ilona-sziget bazaltja 18-8%-ban, felszín -ről betolódott, óceáni kéreg eredetű olvadékot is tartalmaz. A jelenlegi Pb, Sr, Nd és Hf izotóparányok alap ján és a radioaktív bomlást figyelembe véve a szubdukált óceáni kéreg tartozódási ideje a köpenyben minimálisan 1,2 milliárd év lehetett (KAWABATA et al 2011).…”

Section: úJratermékenyülés (Refertilization)unclassified

Köpenyeredetű kőzetek felismerésének története és szerepe a geológiai gondolkodás fejlődésében

Embey-Isztin

2017

Földt. Közl.

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Since the beginning of the 1960 th two new events have revolutionized the evolution of geological thought. One of them, the plate tectonics, which is well known to the public, the other one is the recognition of mantle-derived rocks and the new results related to the investigation of the latter samples. Even if these results have also revolutionized the earth sciences, the real significance of this issue is known to a narrower group of specialists only. The present paper discusses the history of recognition of mantle samples and tries to demonstrate the immense progress of our knowledge due to the detailed investigations of these rock samples. Keywords: history of science, mantle, peridotite ÖsszefoglalásAz 1960-as évek elejétől két új momentum forradalmasította a geológiai gondolkodás fejlődését. Az egyik, a lemeztektonika, mely széles körben vált ismerté, a másik a köpenyszármazású kőzetek azonosítása és az ebből fakadó új eredmények. Bár ez utóbbi is gyökerestül változtatta meg a geológia tudományát, ennek igazi jelentőségét inkább csak a szakemberek ismerik. Ez a dolgozat a köpenykőzetek felismerésének történetét követi nyomon, valamint néhány kira gadott példán keresztül igyekszik bemutatni azt az óriási fejlődést, melyet e kőzetek részletes vizsgálatainak köszön hetünk.

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The Petrology and Geochemistry of St. Helena Alkali Basalts: Evaluation of the Oceanic Crust-recycling Model for HIMU OIB

Cited by 129 publications

References 121 publications

Inferred time- and temperature-dependent cation ordering in natural titanomagnetites

Inferred time- and temperature-dependent cation ordering in natural titanomagnetites

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

Köpenyeredetű kőzetek felismerésének története és szerepe a geológiai gondolkodás fejlődésében

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